Renticular lens, surface light source, and liquid crystal display apparatus

A surface light source, comprising:

• a light guiding plate made of a light transmitting plate;
• a linear light source arranged adjacent to at least one side edge of said light guiding plate;
• a light isotopic diffusing layer layered on the front surface of said light guiding plate;
• and
• a lenticular lens comprising:
• a light transmitting substrate having a first surface and a second surface opposite to said first surface;
• and a plurality of lens elements elongated on the first surface of said light transmitting substrate, having concave shaped cross sections, and defined in such a way that ridges thereof are aligned in parallel, wherein 30.degree..ltoreq..theta..sub.10% .ltoreq.100.degree. and R.ltoreq.20%, where .theta..sub.10% is a diffusing angle range with respect to normal of the first surface in the case that when light is entered from the second surface or first surface and transmitted from the first surface or second surface, the intensity of the light transmitted is equal to more than 10% of the intensity of the light transmitted in a peak direction of a main lobe;
• and R is the ratio of side lobes to main lobe, and wherein each of said lens elements has a triangular prism shape, the vertical angle of each of said lens elements being in the range from 95.degree. to 110.degree.,
• wherein the front surface of said lenticular lens is defined on a diffused light emitting surface.

A liquid crystal display apparatus having a rear surface, comprising:

• a transmission type liquid crystal display device;
• and
• a surface light source, comprising:
• a light transmitting substrate having a first surface and a second surface opposite to said first surface;
• and
• a plurality of lens elements elongated on the first surface of said light transmitting substrate, having concave shaped cross sections, and defined in such a way that ridges thereof are aligned in parallel,
• wherein
• 30.degree..ltoreq..theta..sub.10% .ltoreq.100.degree. and R.ltoreq.20%,
• where .theta..sub.10% is a diffusing angle range with respect to normal of the first surface in the case that when light is entered from the second surface or first surface and transmitted from the first surface or second surface, the intensity of the light transmitted is equal to or more than 10% of the intensity of the light transmitted in a peak direction of a main lobe;
• and R is the ratio of side lobes to main lobe, and
• wherein each of said lens elements has a triangular prism shape, the vertical angle of each of said lens elements being in the range from 95.degree. to 110.degree., said surface light source being disposed on the rear surface of said liquid crystal display device.

A surface light source, comprising:

• a light guiding member formed of a light transmitting plate;
• a linear light source arranged adjacent to at least one side edge of said light guiding plate;
• a light isotopic diffusing layer layered on the front surface of said light guiding plate;
• and
• a lenticular lens, comprising:
• a light transmitting substrate having a first surface and a second surface opposite to said first surface;
• and
• a plurality of lens elements elongated on the first surface of said light transmitting substrate, having concave shaped cross sections, and defined in such a way that ridges thereof are aligned in parallel,
• wherein
• 30.degree..ltoreq..theta..sub.10% .ltoreq.100.degree. and R.ltoreq.20%,
• where .theta..sub.10% is a diffusing angle range with respect to normal of the first surface in the case that when light is entered from the second surface or first surface and transmitted from the first surface or second surface, the intensity of the light transmitted is equal to or more than 10% of the intensity of the light transmitted in a peak direction of a main lobe;
• and R is the ratio of side lobes to main lobe, wherein aid lens elements have concave shapes and are continuously formed in such a way that the shape of the main cross section which is cut perpendicular to the longer axis accords with a quadratic curve, a Rankine egg shape, or a curve expressed by a linear function,
• wherein the front surface of said lenticular lens is defined on a diffused light emitting surface.

A surface light source, comprising:

• at least one point light source;
• a lamp house adapted to cover said light source and having a surface with an opening;
• and
• a lenticular lens, comprising:
• a light transmitting substrate having a first surface and a second surface opposite to said first surface;
• and
• a plurality of lens elements elongated on the first surface of said light transmitting substrate, having concave shaped cross sections, and defined in such a way that ridges thereof are aligned in parallel,
• wherein
• 30.degree..ltoreq..theta..sub.10% .ltoreq.100.degree. and R.ltoreq.20%,
• where .theta..sub.10% is a diffusing angle range with respect to normal of the first surface in the case that when light is entered from the second surface or first surface and transmitted from the first surface or second surface, the intensity of the light transmitted is equal to or more than 10% of the intensity of the light transmitted in a peak direction of a main lobe;
• and R is the ratio of side lobes to main lobe, wherein aid lens elements have concave shapes and are continuously formed in such a way that the shape of the main cross section which is cut perpendicular to the longer axis accords with a quadratic curve, a Rankine egg shape, or a curve expressed by a linear function, said lenticular lens being adapted to cover said opening,
• wherein the front surface of said lenticular lens is defined on a diffused light emitting surface.

A liquid crystal display apparatus having a rear surface, comprising:

• a transmission type liquid crystal display device;
• and
• a surface light source comprising:
• a light guiding member formed of a light transmitting plate;
• a linear light source arranged adjacent to at least one side edge of said light guiding plate;
• a light isotopic diffusing layer layered on the front surface of said light guiding plate;
• and
• a lenticular lens, comprising:
• a light transmitting substrate having a first surface and a second surface opposite to said first surface;
• and
• a plurality of lens elements elongated on the first surface of said light transmitting substrate, having concave shaped cross sections, and defined in such a way that ridges thereof are aligned in parallel,
• wherein
• 30.degree..ltoreq..theta..sub.10% .ltoreq.100.degree. and R.ltoreq.20%,
• where .theta..sub.10% is a diffusing angle range with respect to normal of the first surface in the case that when light is entered from the second surface or first surface and transmitted from the first surface or second surface, the intensity of the light transmitted is equal to or more than 10% of the intensity of the light transmitted in a peak direction of a main lobe;
• and R is the ratio of side lobes to main lobe, wherein aid lens elements have concave shapes and are continuously formed in such a way that the shape of the main cross section which is cut perpendicular to the longer axis accords with a quadratic curve, a Rankine egg shape, or a curve expressed by a linear function,
• wherein the front surface of said lenticular lens is defined on a diffused light emitting surface.

A lens sheet having a mat surface whose surface roughness is up to 100 .mu.m, and the mat surface is formed on the non-lens surface of a convex lenticular lens comprising:

• a light transmitting substrate having a first surface and a second surface opposite to said first surface;
• and
• a plurality of lens elements elongated on the first surface of said light transmitting substrate, having concave shaped cross sections, and defined in such a way that ridges thereof are aligned in parallel,
• wherein
• 30.degree..ltoreq..theta..sub.10% .ltoreq.100.degree. and R.ltoreq.20%,
• where .theta..sub.10% is a diffusing angle range with respect to normal of the first surface in the case that when light is entered from the second surface or first surface and transmitted from the first surface or second surface, the intensity of the light transmitted is equal to or more than 10% of the intensity of the light transmitted in a peak direction of a main lobe;
• and R is the ratio of side lobes to main lobe,
• wherein said lens elements have an elliptic shape and are defined in such a way that ridges thereof are aligned in parallel with each other, the longer axis direction of said lens elements according with the normal direction of a light emitting surface thereof, the following relation being satisfied:
• 1.1.times.n/(n.sup.2 -1).sup.1/2 .gtoreq.length of longer axis/length of shorter axis
• .gtoreq.0.9.times.n/(n.sup.2 -1).sup.1/2
• where n is the refractive index of said lens element.

A surface light source comprising:

• a light guiding member made of a light transmitting plate;
• at least one linear light source arranged on at least one side edge of the light guiding member;
• at least one light reflecting layer disposed on the rear surface of the light guiding member;
• and
• a concave lenticular lens comprising:
• a light transmitting substrate having a first surface and a second surface opposite to said first surface;
• and
• a plurality of lens elements elongated on the first surface of said light transmitting substrate, having concave shaped cross sections, and defined in such a way that ridges thereof are aligned in parallel,
• wherein
• 30.degree..ltoreq..theta..sub.10% .ltoreq.100.degree. and R.ltoreq.20%,
• where .theta..sub.10% is a diffusing angle range with respect to normal of the first surface in the case that when light is entered from the second surface or first surface and transmitted from the first surface or second surface, the intensity of the light transmitted is equal to or more than 10% of the intensity of the light transmitted in a peak direction of a main lobe;
• and R is the ratio of side lobes to main lobe,
• wherein said lens elements have an elliptic shape and are defined in such a way that ridges thereof are aligned in parallel with each other, the longer axis direction of said lens elements according with the normal direction of a light emitting surface thereof, the following relation being satisfied:
• 1.1.times.n/(n.sup.2 -1).sup.1/2 .gtoreq.length of longer axis/length of shorter axis
• 0.9.times.n/(n.sup.2 -1).sup.1/2
• where n is the refractive index of said lens elements layered on a light emitting surface of the light guiding member.

A display apparatus, comprising:

• a the surface light source comprising:
• a light guiding member made of a light transmitting plate;
• at least one linear light source arranged on at least one side edge of the light guiding member;
• at least one light reflecting layer disposed on the rear surface of the light guiding member;
• and
• a concave lenticular lens comprising:
• a light transmitting substrate having a first surface and a second surface opposite to said first surface;
• and
• a plurality of lens elements elongated on the first surface of said light transmitting substrate, having concave shaped cross sections, and defined in such a way that ridges thereof are aligned in parallel,
• wherein
• 30.degree..ltoreq..theta..sub.10% .ltoreq.100.degree. and R.ltoreq.20%,
• where .theta..sub.10% is a diffusing angle range with respect to normal of the first surface in the case that when light is entered from the second surface or first surface and transmitted from the first surface or second surface, the intensity of the light transmitted is equal to or more than 10% of the intensity of the light transmitted in a peak direction of a main lobe;
• and R is the ratio of side lobes to main lobe,
• wherein said lens elements have an elliptic shape and are defined in such a way that ridges thereof are aligned in parallel with each other, the longer axis direction of said lens elements according with the normal direction of a light emitting surface thereof, the following relation being satisfied:
• 1.1.times.n/(n.sup.2 -1).sup.1/2 .gtoreq.length of longer axis/length of shorter axis
• .gtoreq.0.9.times.n/(n.sup.2 -1).sup.1/2
• where n is the refractive index of said lens elements layered on a light emitting surface of the light guiding member;
• and
• a transmission type display device which is layered over the light emitting urface of the surface light source.

A surface light source, comprising:

• at least one linear light source having a lower surface;
• a lamp house that covers the lower surface and side surface of the light source and has an opening on the upper surface of the light source and an inner reflecting surface;
• and
• a lenticular lens comprising:
• a light transmitting substrate having a first surface and a second surface opposite to said first surface;
• and
• a plurality of lens elements elongated on the first surface of said light transmitting substrate, having concave shaped cross sections, and defined in such a way that ridges thereof are aligned in parallel,
• wherein
• 30.degree..ltoreq..theta..sub.10% .ltoreq.100.degree. and R.ltoreq.20%,
• where .theta..sub.10% is a diffusing angle range with respect to normal of the first surface in the case that when light is entered from the second surface or first surface and transmitted from the first surface or second surface, the intensity of the light transmitted is equal to or more than 10% of the intensity of the light transmitted in a peak direction of a main lobe;
• and R is the ratio of side lobes to main lobe,
• wherein said lens elements have an elliptic shape and are defined in such a way that ridges thereof are aligned in parallel with each other, the longer axis direction of said lens elements according with the normal direction of a light emitting surface thereof, the following relation being satisfied:
• 1.1.times.n/(n.sup.2 -1).sup.1/2 a length of longer axis/length of shorter axis
• .gtoreq.0.9.times.n/(n.sup.2 -1).sup.1/2
• where n is the refractive index of said lens elements covering the opening of said lamp house.

A display apparatus, comprising:

• a surface light source comprising:
• at least one linear light source having a lower surface;
• a lamp house that covers the lower surface and side surface of the light source and has an opening on the upper surface of the light source and an inner reflecting surface;
• and
• a lenticular lens comprising:
• a light transmitting substrate having a first surface and a second surface opposite to said first surface;
• and
• a plurality of lens elements elongated on the first surface of said light transmitting substrate, having concave shaped cross sections, and defined in such a way that ridges thereof are aligned in parallel,
• wherein
• 30.degree..ltoreq..theta..sub.10% .ltoreq.100.degree. and R.ltoreq.20%,
• where .theta..sub.10% is a diffusing angle range with respect to normal of the first surface in the case that when light is entered from the second surface or first surface and transmitted from the first surface or second surface, the intensity of the light transmitted is equal to or more than 10% of the intensity of the light transmitted in a peak direction of a main lobe;
• and R is the ratio of side lobes to main lobe,
• wherein said lens elements have an elliptic shape and are defined in such a way that ridges thereof are aligned in parallel with each other, the longer axis direction of said lens elements according with the normal direction of a light emitting surface thereof, the following relation being satisfied:
• 1.1.times.n/(n.sup.2 -1).sup.1/2 .gtoreq.length of longer axis/length of shorter axis
• .gtoreq.0.9.times.n/(n.sup.2 -1).sup.1/2
• where n is the refractive index of said lens elements covering the opening of said lamp house;
• and
• a transmission type display device that is layered over the light emitting surface of the surface light source.

A lens sheet, having a mat surface whose surface roughness is up to 100 .mu.m, and the mat surface is formed on the non-lens surface of a convex lenticular lens comprising:

• a light transmitting substrate having a first surface and a second surface opposite to said first surface;
• and
• a plurality of lens elements elongated on the first surface of said light transmitting substrate, having concave shaped cross sections, and defined in such a way that ridges thereof are aligned in parallel,
• wherein
• 30.degree..ltoreq..theta..sub.10% 100.degree. and R.ltoreq.20%,
• where .theta..sub.10% is a diffusing angle range with respect to normal of the first surface in the case that when light is entered from the second surface or first surface and transmitted from the first surface or second surface, the intensity of the light transmitted is equal to or more than 10% of the intensity of the light transmitted in a peak direction of a main lobe;
• and R is the ratio of side lobes to main lobe,
• wherein said lens elements have a hyperbolic shape and are defined in such a way that ridges thereof are aligned in parallel with each other, the longer axis direction of said lens elements according with the normal direction of a light emitting surface thereof, the following relation being satisfied:
• 1.1.times.n/(n.sup.2 -1).sup.1/2 .gtoreq.slope of asymptotic line
• .gtoreq.0.9.times.n/(n.sup.2 -1).sup.1/2
• where n is the refractive index of said lens elements.

A surface light source comprising:

• a light guiding member made of a light transmitting plate;
• at least one linear light source arranged on at least one side edge of the light guiding member;
• at least one light reflecting layer disposed on the rear surface of the light guiding member;
• and
• a concave lenticular lens comprising:
• a light transmitting substrate having a first surface and a second surface opposite to said first surface;
• and
• a plurality of lens elements elongated on the first surface of said light transmitting substrate, having concave shaped cross sections, and defined in such a way that ridges thereof are aligned in parallel,
• wherein
• 30.degree..ltoreq..theta..sub.10% 100.degree. and R.ltoreq.20%,
• where .theta..sub.10% is a diffusing angle range with respect to normal of the first surface in the case that when light is entered from the second surface or first surface and transmitted from the first surface or second surface, the intensity of the light transmitted is equal to or more than 10% of the intensity of the light transmitted in a peak direction of a main lobe;
• and R is the ratio of side lobes to main lobe,
• wherein said lens elements have a hyperbolic shape and are defined in such a way that ridges thereof are aligned in parallel with each other, the longer axis direction of said lens elements according with the normal direction of a light emitting surface thereof, the following relation being satisfied:
• 1.1.times.n/(n.sup.2 -1).sup.1/2 a slope of asymptotic line
• .gtoreq.0.9.times.n/(n.sup.2 -1).sup.1/2
• where n is the refractive index of said lens elements layered on a light emitting surface of the light guiding member.

A display apparatus, comprising:

• a surface light source comprising:
• a light guiding member made of a light transmitting plate;
• at least one linear light source arranged on at least one side edge of the light guiding member;
• at least one light reflecting layer disposed on the rear surface of the light guiding member;
• and
• a concave lenticular lens comprising:
• a light transmitting substrate having a first surface and a second surface opposite to said first surface;
• and
• a plurality of lens elements elongated on the first surface of said light transmitting substrate, having concave shaped cross sections, and defined in such a way that ridges thereof are aligned in parallel,
• wherein
• 30.degree..ltoreq..theta..sub.10% 100.degree. and R.ltoreq.20%,
• where .theta..sub.10% is a diffusing angle range with respect to normal of the first surface in the case that when light is entered from the second surface or first surface and transmitted from the first surface or second surface, the intensity of the light transmitted is equal to or more than 10% of the intensity of the light transmitted in a peak direction of a main lobe;
• and R is the ratio of side lobes to main lobe,
• wherein said lens elements have a hyperbolic shape and are defined in such a way that ridges thereof are aligned in parallel with each other, the longer axis direction of said lens elements according with the normal direction of a light emitting surface thereof, the following relation being satisfied:
• 1.1.times.n/(n.sup.2 -1).sup.1/2 .gtoreq.slope of asymptotic line
• .gtoreq.0.9.times.n/(n.sup.2 -1).sup.1/2
• where n is the refractive index of said lens elements layered on a light emitting surface of the light guiding member;
• and
• a transmission type display device that is layered over the light emitting surface of the surface light source.

A surface light source, comprising:

• at least one linear or point light source;
• a lamp house that covers the lower surface and side surface of the light source and has an opening on the upper surface of the light source and an inner reflecting surface;
• and
• a lenticular lens comprising:
• a light transmitting substrate having a first surface and a second surface opposite to said first surface;
• and
• a plurality of lens elements elongated on the first surface of said light transmitting substrate, having concave shaped cross sections, and defined in such a way that ridges thereof are aligned in parallel,
• wherein
• 30.degree..ltoreq..theta..sub.10% 100.degree. and R.ltoreq.20%,
• where .theta..sub.10% is a diffusing angle range with respect to normal of the first surface in the case that when light is entered from the second surface or first surface and transmitted from the first surface or second surface, the intensity of the light transmitted is equal to or more than 10% of the intensity of the light transmitted in a peak direction of a main lobe;
• and R is the ratio of side lobes to main lobe,
• wherein said lens elements have a hyperbolic shape and are defined in such a way that ridges thereof are aligned in parallel with each other, the longer axis direction of said lens elements according with the normal direction of a light emitting surface thereof, the following relation being satisfied:
• 1.1.times.n/(n.sup.2 -1).sup.1/2 .gtoreq.slope of asymptotic line
• .gtoreq.0.9.times.n/(n.sup.2 -1).sup.1/2
• where n is the refractive index of said lens elements covering the opening of said lamp house.

A display apparatus, comprising:

• a surface light source comprising:
• at least one linear or point light source;
• a lamp house that covers the lower surface and side surface of the light source and has an opening on the upper surface of the light source and an inner reflecting surface;
• and
• a lenticular lens comprising:
• a light transmitting substrate having a first surface and a second surface opposite to said first surface;
• and
• a plurality of lens elements elongated on the first surface of said light transmitting substrate, having concave shaped cross sections, and defined in such a way that ridges thereof are aligned in parallel,
• wherein
• 30.degree..ltoreq..theta..sub.10% 100.degree. and R.ltoreq.20%,
• where .theta..sub.10% is a diffusing angle range with respect to normal of the first surface in the case that when light is entered from the second surface or first surface and transmitted from the first surface or second surface, the intensity of the light transmitted is equal to or more than 10% of the intensity of the light transmitted in a peak direction of a main lobe;
• and R is the ratio of side lobes to main lobe,
• wherein said lens elements have a hyperbolic shape and are defined in such a way that ridges thereof are aligned in parallel with each other, the longer axis direction of said lens elements according with the normal direction of a light emitting surface thereof, the following relation being satisfied:
• 1.1.times.n/(n.sup.2 -1).sup.1/2 .gtoreq.slope of asymptotic line
• .gtoreq.0.9.times.n/(n.sup.2 -1).sup.1/2
• where n is the refractive index of said lens elements covering the opening of said lamp house;
• and
• a transmission type display device that is layered over the light emitting surface of the surface light source.

A surface light source comprising:

• a light guiding member made of a light transmitting plate;
• at least one linear light source arranged on at least one side edge of the light guiding member;
• at least one light reflecting layer disposed on the rear surface of the light guiding member;
• and
• a concave lenticular lens comprising:
• a light transmitting substrate having a first surface and a second surface opposite to said first surface;
• and
• a plurality of lens elements elongated on the first surface of said light transmitting substrate, having concave shaped cross sections, and defined in such a way that ridges thereof are aligned in parallel,
• wherein
• 30.degree..ltoreq..theta..sub.10% 100.degree. and R.ltoreq.20%,
• where .theta..sub.10% is a diffusing angle range with respect to normal of the first surface in the case that when light is entered from the second surface or first surface and transmitted from the first surface or second surface, the intensity of the light transmitted is equal to or more than 10% of the intensity of the light transmitted in a peak direction of a main lobe;
• and R is the ratio of side lobes to main lobe,
• wherein said lens elements have an elliptic shape and are defined in such a way that ridges thereof are aligned in parallel with each other, the longer axis direction of said lens elements according with the normal direction of a light emitting surface thereof, the cutting depth and the refractive index of said lens elements being given by:
• 1.40.ltoreq.refractive index.ltoreq.1.6,
• 1.20.ltoreq.length of longer axis/length of shorter axis.ltoreq.2.00, and
• 0.1.ltoreq.cutting depth/length of longer axis.ltoreq.0.50 layered on a light emitting surface of the light guiding member.

A display apparatus, comprising:

• a surface light source comprising:
• a light guiding member made of a light transmitting plate;
• at least one linear light source arranged on at least one side edge of the light guiding member;
• at least one light reflecting layer disposed on the rear surface of the light guiding member;
• and
• a concave lenticular lens comprising:
• a light transmitting substrate having a first surface and a second surface opposite to said first surface;
• and
• a plurality of lens elements elongated on the first surface of said light transmitting substrate, having concave shaped cross sections, and defined in such a way that ridges thereof are aligned in parallel,
• wherein
• 30.degree..theta..sub.10% 100.degree. and R.ltoreq.20%,
• where .theta..sub.10% is a diffusing angle range with respect to normal of the first surface in the case that when light is entered from the second surface or first surface and transmitted from the first surface or second surface, the intensity of the light transmitted is equal to or more than 10% of the intensity of the light transmitted in a peak direction of a main lobe;
• and R is the ratio of side lobes to main lobe,
• wherein said lens elements have an elliptic shape and are defined in such a way that ridges thereof are aligned in parallel with each other, the longer axis direction of said lens elements according with the normal direction of a light emitting surface thereof, the cutting depth and the refractive index of said lens elements being given by:
• 1.40.ltoreq.refractive index.ltoreq.1.6,
• 1.20.ltoreq.length of longer axis/length of shorter axis.ltoreq.2.00, and
• 0.1.ltoreq.cutting depth/length of longer axis.ltoreq.0.50 layered on a light emitting surface of the light guiding member;
• and
• a transmission type display device that is layered over the light emitting surface of the surface light source.

A surface light source, comprising:

• at least one linear light source having a lower surface;
• a lamp house that covers the lower surface and side surface of the light source and has an opening on the upper surface of the light source and an inner reflecting surface;
• and
• a lenticular lens comprising:
• a light transmitting substrate having a first surface and a second surface opposite to said first surface;
• and
• a plurality of lens elements elongated on the first surface of said light transmitting substrate, having concave shaped cross sections, and defined in such a way that ridges thereof are aligned in parallel,
• wherein
• 30.degree..ltoreq..theta..sub.10% 100.degree. and R.ltoreq.20%,
• where .theta..sub.10% is a diffusing angle range with respect to normal of the first surface in the case that when light is entered from the second surface or first surface and transmitted from the first surface or second surface, the intensity of the light transmitted is equal to or more than 10% of the intensity of the light transmitted in a peak direction of a main lobe;
• and R is the ratio of side lobes to main lobe,
• wherein said lens elements have an elliptic shape and are defined in such a way that ridges thereof are aligned in parallel with each other, the longer axis direction of said lens elements according with the normal direction of a light emitting surface thereof, the cutting depth and the refractive index of said lens elements being given by:
• 1.40.ltoreq.refractive index.ltoreq.1.6,
• 1.20.ltoreq.length of longer axis/length of shorter axis.ltoreq.2.00, and
• 0.1.ltoreq.cutting depth/length of longer axis.ltoreq.0.50 covering the opening of said lamp house.

A lenticular lens, comprising:

• a light transmitting substrate having a first surface and a second surface opposite to said first surface;
• and
• a plurality of lens elements elongated on the first surface of said light transmitting substrate, having convex shaped cross sections, and defined in such a way that ridges thereof are aligned an parallel,
• wherein
• 30.degree..ltoreq..theta..sub.10% .ltoreq.100.degree. and R.ltoreq.20%,
• where .theta..sub.10% is a diffusing angle range with respect to normal of the first surface in the case that when light is entered from the second surface or first surface and transmitted from the first surface or second surface, the intensity of the light transmitted is equal to or more than 10% of the intensity of the light transmitted in a peak direction of a main lobe;
• and R is the ratio of side lobes to main lobe.

A surface light source comprising:

• a light guiding plate made of a rectangular parallelpiped cavity;
• a linear light source arranged adjacent to at least one side edge of said light guiding plate;
• a light isotopic diffusing layer layered on the front surface of said light guiding plate;
• and
• a lenticular lens comprising:
• a light transmitting substrate having a first surface and a second surface opposite to said first surface;
• and
• a plurality of lens elements elongated on the first surface of said light transmitting substrate, having concave shaped cross sections, and defined in such a way that ridges thereof are aligned in parallel,
• wherein
• 30.degree..theta..sub.10% .ltoreq.100.degree. and R.ltoreq.20%,
• where .theta..sub.10% is a diffusing angle range with respect to normal of the first surface in the case that when light is entered from the second surface or first surface and transmitted from the first surface or second surface, the intensity o the light transmitted is equal to or more than 10% of the intensity of the light transmitted in a peak direction of a main lobe;
• and R is the ratio of side lobes to main lobe wherein each of said lens elements has a triangular prism shape, the vertical angle of each of said lens elements being in the range from 95.degree. to 110.degree.,
• wherein the front surface of said lenticular lens is defined on a diffused light emitting surface.

A surface light source comprising:

• a light guiding member formed of a rectangular parallelpiped cavity;
• a linear light source arranged adjacent to at least one side edge of said light guiding plate;
• a light isotopic diffusing layer layered on the first surface of said light guiding plate;
• and
• a lenticular lens, comprising:
• a light transmitting substrate having a first surface and a second surface opposite to said first surface;
• and
• a plurality of lens elements elongated on the first surface of said light transmitting substrate, having concave shaped cross sections, and defined in such a way that ridges thereof are aligned in parallel,
• wherein
• 30.degree..ltoreq..theta..sub.10% .ltoreq.100.degree. and R.ltoreq.20%,
• where .theta..sub.10% is a diffusing angle range with respect to normal of the first surface in the case that when light is entered from the second surface or first surface and transmitted from the first surface or second surface, the intensity of the light transmitted is equal to or more than 10% of the intensity of the light transmitted in a peak direction of a main lobe;
• and R is the ratio of side lobes to main lobe, wherein aid lens elements have concave shapes and are continuously formed in such a way that the shape of the main cross section which is cut perpendicular to the longer axis accords with a quadratic curve, a Rankine egg shape, or a curve expressed by a linear function,
• wherein the first surface of said lenticular lens is defined on a diffused light emitting surface.

A surface light source, comprising:

• at least one linear light source;
• a lamp house adapted to cover said light source and having a surface with an opening;
• and
• a lenticular lens, comprising:
• a light transmitting substrate having a first surface and a second surface opposite to said first surface;
• and
• a plurality of lens elements elongated on the first surface of said light transmitting substrate, having concave shaped cross sections, and defined in such a way that ridges thereof are aligned in parallel,
• wherein
• 30.degree..ltoreq..theta..sub.10% .ltoreq.100.degree. and R.ltoreq.20%,
• where .theta..sub.10% is a diffusing angle range with respect to normal of the first surface in the case that when light is entered from the second surface or first surface and transmitted from the first surface or second surface, the intensity of the light transmitted is equal to or more than 10% of the intensity of the light transmitted in a peak direction of a main lobe;
• and R is the ratio of side lobes to main lobe, wherein aid lens elements have concave shapes and are continuously formed in such a way that the shape of the main cross section which is cut perpendicular to the longer axis accords with a quadratic curve, a Rankine egg shape, or a curve expressed by a linear function, said lenticular lens being adapted to cover said opening,
• wherein the first surface of said lenticular lens is defined on a diffused light emitting surface.

A lens sheet, having a mat surface whose surface roughness is up to 100 .mu.m, and the mat surface is formed on the non-lens surface of a concave lenticular lens comprising:

• a light transmitting substrate having a first surface and a second surface opposite to said first surface;
• and
• a plurality of lens elements elongated on the first surface of said light transmitting substrate, having concave shaped cross sections, and defined in such a way that ridges thereof are aligned in parallel,
• wherein
• 30.degree..ltoreq..theta..sub.10% .ltoreq.100.degree. and R.ltoreq.20%,
• where .theta..sub.10% is a diffusing angle range with respect to normal of the first surface in the case that when light is entered from the second surface or first surface and transmitted from the first surface or second surface, the intensity of the light transmitted is equal to or more than 10% of the intensity of the light transmitted in a peak direction of a main lobe;
• and R is the ratio of side lobes to main lobe,
• wherein said lens elements have an elliptic shape and are defined in such a way that ridges thereof are aligned in parallel with each other, the longer axis direction of said lens elements according with the normal direction of a light emitting surface thereof, the following relation being satisfied:
• 1.1.times.n/(n.sup.2 -1).sup.1/2 .gtoreq.length of longer axis/length of shorter axis
• .gtoreq.0.9.times.n/(n.sup.2 -1).sup.1/2
• where n is the refractive index of said lens elements.

A lens sheet, having a mat surface whose surface roughness is up to 100 .mu.m, and the mat surface is formed on the non-lens surface of a concave lenticular lens comprising:

• a light transmitting substrate having a first surface and a second surface opposite to said first surface;
• and
• a plurality of lens elements elongated on the first surface of said light transmitting substrate, having concave shaped cross sections, and defined in such a way that ridges thereof are aligned in parallel,
• wherein
• 30.degree..ltoreq..theta..sub.10% 100.degree. and R.ltoreq.20%,
• where .theta..sub.10% is a diffusing angle range with respect to normal of the first surface in the case that when light is entered from the second surface or first surface and transmitted from the first surface or second surface, the intensity of the light transmitted is equal to or more than 10% of the intensity of the light transmitted in a peak direction of a main lobe;
• and R is the ratio of side lobes to main lobe,
• wherein said lens elements have a hyperbolic shape and are defined in such a way that ridges thereof are aligned in parallel with each other, the longer axis direction of said lens elements according with the normal direction of a light emitting surface thereof, the following relation being satisfied:
• 1.1.times.n/(n.sup.2 -1).sup.1/2 .gtoreq.slope of asymptotic line
• .gtoreq.0.9.times.n/(n.sup.2 -1).sup.1/2
• where n is the refractive index of said lens elements.

A surface light source comprising:

• a light guiding member made of a rectangular parallelpiped cavity;
• at least one linear light source arranged on at least one side edge of the light guiding member;
• at least one light reflecting layer disposed on the rear surface of the light guiding member;
• and
• a concave lenticular lens comprising:
• a light transmitting substrate having a first surface and a second surface opposite to said first surface;
• and
• a plurality of lens elements elongated on the first surface of said light transmitting substrate, having concave shaped cross sections, and defined in such a way that ridges thereof are aligned in parallel,
• wherein
• 30.degree..ltoreq..theta..sub.10% .ltoreq.100.degree. and R.ltoreq.20%,
• where .theta..sub.10% is a diffusing angle range with respect to normal of the first surface in the case that when light is entered from the second surface or first surface and transmitted from the first surface or second surface, the intensity of the light transmitted is equal to or more than 10% of the intensity of the light transmitted in a peak direction of a main lobe;
• and R is the ratio of side lobes to main lobe,
• wherein said lens elements have an elliptic shape and are defined in such a way that ridges thereof are aligned in parallel with each other, the longer axis direction of said lens elements according with the normal direction of a light emitting surface thereof, the following relation being satisfied:
• 1.1.times.n/(n.sup.2 -1).sup.1/2 .gtoreq.length of longer axis/length of shorter axis
• .gtoreq.0.9.times.n/(n.sup.2 -1).sup.1/2
• where n is the refractive index of said lens elements layered on a light emitting surface of the light guiding member.

A surface light source comprising:

• a light guiding member made of a light transmitting plate;
• at least one point light source arranged on at least one side edge of the light guiding member;
• at least one light reflecting layer disposed on the rear surface of the light guiding member;
• and
• a concave lenticular lens comprising:
• a light transmitting substrate having a first surface and a second surface opposite to said first surface;
• and
• a plurality of lens elements elongated on the first surface of said light transmitting substrate, having concave shaped cross sections, and defined in such a way that ridges thereof are aligned in parallel,
• wherein
• 30.degree..ltoreq..theta..sub.10% .ltoreq.100.degree. and R.ltoreq.20%,
• where .theta..sub.10% is a diffusing angle range with respect to normal of the first surface in the case that when light is entered from the second surface or first surface and transmitted from the first surface or second surface, the intensity of the light transmitted is equal to or more than 10% of the intensity of the light transmitted in a peak direction of a main lobe;
• and R is the ratio of side lobes to main lobe,
• wherein said lens elements have an elliptic shape and are defined in such a way that ridges thereof are aligned in parallel with each other, the longer axis direction of said lens elements according with the normal direction of a light emitting surface thereof, the following relation being satisfied:
• 1.1.times.n/(n.sup.2 -1).sup.1/2 .gtoreq.length of longer axis/length of shorter axis
• .gtoreq.0.9.times.n/(n.sup.2 -1).sup.1/2
• where n is the refractive index of said lens elements layered on a light emitting surface of the light guiding member.

A surface light source comprising:

• a light guiding member made of a rectangular parallelpiped cavity;
• at least one point light source arranged on at least one side edge of the light guiding member;
• at least one light reflecting layer disposed on the rear surface of the light guiding member;
• and
• a concave lenticular lens comprising:
• a light transmitting substrate having a first surface and a second surface opposite to said first surface;
• and
• a plurality of lens elements elongated on the first surface of said light transmitting substrate, having concave shaped cross sections, and defined in such a way that ridges thereof are aligned in parallel,
• wherein
• 30.degree..ltoreq..theta..sub.10% .ltoreq.100.degree. and R.ltoreq.20%,
• where .theta..sub.10% is a diffusing angle range with respect to normal of the first surface in the case that when light is entered from the second surface or first surface and transmitted from the first surface or second surface, the intensity of the light transmitted is equal to or more than 10% of the intensity of the light transmitted in a peak direction of a main lobe;
• and R is the ratio of side lobes to main lobe,
• wherein said lens elements have an elliptic shape and are defined in such a way that ridges thereof are aligned in parallel with each other, the longer axis direction of said lens elements according with the normal direction of a light emitting surface thereof, the following relation being satisfied:
• 1.1.times.n/(n.sup.2 -1).sup.1/2 .gtoreq.length of longer axis/length of shorter axis
• .gtoreq.0.9.times.n/(n.sup.2 -1).sup.1/2
• where n is the refractive index of said lens elements layered on a light emitting surface of the light guiding member.

A surface light source comprising:

• a light guiding member made of a light transmitting plate;
• at least one linear light source arranged on at least one side edge of the light guiding member;
• at least one light reflecting layer disposed on the rear surface of the light guiding member;
• and
• a convex lenticular lens comprising:
• a light transmitting substrate having a first surface and a second surface opposite to said first surface;
• and
• a plurality of lens elements elongated on the first surface of said light transmitting substrate, having concave shaped cross sections, and defined in such a way that ridges thereof are aligned in parallel,
• wherein
• 30.degree..ltoreq..theta..sub.10% .ltoreq.100.degree. and R.ltoreq.20%,
• where .theta..sub.10% is a diffusing angle range with respect to normal of the first surface in the case that when light is entered from the second surface or first surface and transmitted from the first surface or second surface, the intensity of the light transmitted is equal to or more than 10% of the intensity of the light transmitted in a peak direction of a main lobe;
• and R is the ratio of side lobes to main lobe,
• wherein said lens elements have an elliptic shape and are defined in such a way that ridges thereof are aligned in parallel with each other, the longer axis direction of said lens elements according with the normal direction of a light emitting surface thereof, the following relation being satisfied:
• 1.1.times.n/(n.sup.2 -1).sup.1/2 .gtoreq.length of longer axis/length of shorter axis
• .gtoreq.0.9.times.n/(n.sup.2 -1).sup.1/2
• where n is the refractive index of said lens elements layered on a light emitting surface of the light guiding member.

A surface light source comprising:

• a light guiding member made of a light transmitting plate;
• at least one point light source arranged on at least one side of the light guiding member;
• at least one light reflecting layer disposed on the rear surface of the light guiding member;
• and
• a convex lenticular lens comprising:
• a light transmitting substrate having a first surface and a second surface opposite to said first surface;
• and
• a plurality of lens elements elongated on the first surface of said light transmitting substrate, having concave shaped cross sections, and defined in such a way that ridges thereof are aligned in parallel,
• wherein
• 30.degree..ltoreq..theta..sub.10% .ltoreq.100.degree. and R.ltoreq.20%,
• where .theta..sub.10% is a diffusing angle range with respect to normal of the first surface in the case that when light is entered from the second surface or first surface and transmitted from the first surface or second surface, the intensity of the light transmitted is equal to or more than 10% of the intensity of the light transmitted in a peak direction of a main lobe;
• and R is the ratio of side lobes to main lobe,
• wherein said lens elements have an elliptic shape and are defined in such a way that ridges thereof are aligned in parallel with each other, the longer axis direction of said lens elements according with the normal direction of a light emitting surface thereof, the following relation being satisfied:
• 1.1.times.n/(n.sup.2 -1).sup.1/2 .gtoreq.length of longer axis/length of shorter axis
• .gtoreq.0.9.times.n/(n.sup.2 -1).sup.1/2
• where n is the refractive index of said lens elements layered on a light emitting surface of the light guiding member.

A surface light source comprising:

• a light guiding member made of a rectangular parallelpiped cavity;
• at least one linear light source arranged on at least one side edge of the light guiding member;
• at least one light reflecting layer disposed on the rear surface of the light guiding member;
• and
• a convex lenticular lens comprising:
• a light transmitting substrate having a first surface and a second surface opposite to said first surface;
• and
• a plurality of lens elements elongated on the first surface of said light transmitting substrate, having concave shaped cross sections, and defined in such a way that ridges thereof are aligned in parallel,
• wherein
• 30.degree..ltoreq..theta..sub.10% .ltoreq.100.degree. and R.ltoreq.20%,
• where .theta..sub.10% is a diffusing angle range with respect to normal of the first surface in the case that when light is entered from the second surface or first surface and transmitted from the first surface or second surface, the intensity of the light transmitted is equal to or more than 10% of the intensity of the light transmitted in a peak direction of a main lobe;
• and R is the ratio of side lobes to main lobe,
• wherein said lens elements have an elliptic shape and are defined in such a way that ridges thereof are aligned in parallel with each other, the longer axis direction of said lens elements according with the normal direction of a light emitting surface thereof, the following relation being satisfied:
• 1.1.times.n/(n.sup.2 -1).sup.1/2 .gtoreq.length of longer axis/length of shorter axis
• .gtoreq.0.9.times.n/(n.sup.2 -1).sup.1/2
• where n is the refractive index of said lens elements layered on a light emitting surface of the light guiding member.

A surface light source comprising:

• a light guiding member made of a rectangular parallelpiped cavity;
• at least one point light source arranged on at least one side edge of the light guiding member;
• at least one light reflecting layer disposed on the rear surface of the light guiding member;
• and
• a convex lenticular lens comprising:
• a light transmitting substrate having a first surface and a second surface opposite to said first surface;
• and
• a plurality of lens elements elongated on the first surface of said light transmitting substrate, having concave shaped cross sections, and defined in such a way that ridges thereof are aligned in parallel,
• wherein
• 30.degree..ltoreq..theta..sub.10% .ltoreq.100.degree. and R.ltoreq.20%,
• where .theta..sub.10% is a diffusing angle range with respect to normal of the first surface in the case that when light is entered from the second surface or first surface and transmitted from the first surface or second surface, the intensity of the light transmitted is equal to or more than 10% of the intensity of the light transmitted in a peak direction of a main lobe;
• and R is the ratio of side lobes to main lobe,
• wherein said lens elements have an elliptic shape and are defined in such a way that ridges thereof are aligned in parallel with each other, the longer axis direction of said lens elements according with the normal direction of a light emitting surface thereof, the following relation being satisfied:
• 1.1.times.n/(n.sup.2 -1).sup.1/2 .gtoreq.length of longer axis/length of shorter axis
• .gtoreq.0.9.times.n/(n.sup.2 -1).sup.1/2
• where n is the refractive index of said lens elements layered on a light emitting surface of the light guiding member.

A surface light source comprising:

• a light guiding member made of a rectangular parallelpiped cavity;
• at least one linear light source arranged on at least one side edge of the light guiding member;
• at least one light reflecting layer disposed on the rear surface of the light guiding member;
• and
• a concave lenticular lens comprising:
• a light transmitting substrate having a first surface and a second surface opposite to said first surface;
• and
• a plurality of lens elements elongated on the first surface of said light transmitting substrate, having concave shaped cross sections, and defined in such a way that ridges thereof are aligned in parallel,
• wherein
• 30.degree..ltoreq..theta..sub.10% 100.degree. and R.ltoreq.20%,
• where .theta..sub.10% is a diffusing angle range with respect to normal of the first surface in the case that when light is entered from the second surface or first surface and transmitted from the first surface or second surface, the intensity of the light transmitted is equal to or more than 10% of the intensity of the light transmitted in a peak direction of a main lobe;
• and R is the ratio of side lobes to main lobe,
• wherein said lens elements have a hyperbolic shape and are defined in such a way that ridges thereof are aligned in parallel with each other, the longer axis direction of said lens elements according with the normal direction of a light emitting surface thereof, the following relation being satisfied:
• 1.1.times.n/(n.sup.2 -1).sup.1/2 .gtoreq.slope of asymptotic line
• .gtoreq.0.9.times.n/(n.sup.2 -1).sup.1/2
• where n is the refractive index of said lens elements layered on a light emitting surface of the light guiding member.

A surface light source comprising:

• a light guiding member made of a light transmitting plate;
• at least one point light source arranged on at least one side edge of the light guiding member;
• at least one light reflecting layer disposed on the rear surface of the light guiding member;
• and
• a concave lenticular lens comprising:
• a light transmitting substrate having a first surface and a second surface opposite to said first surface;
• and
• a plurality of lens elements elongated on the first surface of said light transmitting substrate, having concave shaped cross sections, and defined in such a way that ridges thereof are aligned in parallel,
• wherein
• 30.degree..ltoreq..theta..sub.10% 100.degree. and R.ltoreq.20%,
• where .theta..sub.10% is a diffusing angle range with respect to normal of the first surface in the case that when light is entered from the second surface or first surface and transmitted from the first surface or second surface, the intensity of the light transmitted is equal to or more than 10% of the intensity of the light transmitted in a peak direction of a main lobe;
• and R is the ratio of side lobes to main lobe,
• wherein said lens elements have a hyperbolic shape and are defined in such a way that ridges thereof are aligned in parallel with each other, the longer axis direction of said lens elements according with the normal direction of a light emitting surface thereof, the following relation being satisfied:
• 1.1.times.n/(n.sup.2 -1).sup.1/2 .gtoreq.slope of asymptotic line
• .gtoreq.0.9.times.n/(n.sup.2 -1).sup.1/2
• where n is the refractive index of said lens elements layered on a light emitting surface of the light guiding member.

A surface light source comprising:

• a light guiding member made of a light transmitting plate;
• at least one point light source arranged on at least one side edge of the light guiding member;
• at least one light reflecting layer disposed on the rear surface of the light guiding member;
• and
• a concave lenticular lens comprising:
• a light transmitting substrate having a first surface and a second surface opposite to said first surface;
• and
• a plurality of lens elements elongated on the first surface of said light transmitting substrate, having concave shaped cross sections, and defined in such a way that ridges thereof are aligned in parallel,
• wherein
• 30.degree..ltoreq..theta..sub.10% 100.degree. and R.ltoreq.20%,
• where .theta..sub.10% is a diffusing angle range with respect to normal of the first surface in the case that when light is entered from the second surface or first surface and transmitted from the first surface or second surface, the intensity of the light transmitted is equal to or more than 10% of the intensity of the light transmitted in a peak direction of a main lobe;
• and R is the ratio of side lobes to main lobe,
• wherein said lens elements have a hyperbolic shape and are defined in such a way that ridges thereof are aligned in parallel with each other, the longer axis direction of said lens elements according with the normal direction of a light emitting surface thereof, the following relation being satisfied:
• 1.1.times.n/(n.sup.2 -1).sup.1/2 .gtoreq.slope of asymptotic line
• .gtoreq.0.9.times.n/(n.sup.2 -1).sup.1/2
• where n is the refractive index of said lens elements layered on a light emitting surface of the light guiding member.

A surface light source comprising:

• a light guiding member made of a rectangular parallelpiped cavity;
• at least one point light source arranged on at least one side edge of the light guiding member;
• at least one light reflecting layer disposed on the rear surface of the light guiding member;
• and
• a concave lenticular lens comprising:
• a light transmitting substrate having a first surface and a second surface opposite to said first surface;
• and
• a plurality of lens elements elongated on the first surface of said light transmitting substrate, having concave shaped cross sections, and defined in such a way that ridges thereof are aligned in parallel,
• wherein
• 30.degree..ltoreq..theta..sub.10% 100.degree. and R.ltoreq.20%,
• where .theta..sub.10% is a diffusing angle range with respect to normal of the first surface in the case that when light is entered from the second surface or first surface and transmitted from the first surface or second surface, the intensity of the light transmitted is equal to or more than 10% of the intensity of the light transmitted in a peak direction of a main lobe;
• and R is the ratio of side lobes to main lobe,
• wherein said lens elements have a hyperbolic shape and are defined in such a way that ridges thereof are aligned in parallel with each other, the longer axis direction of said lens elements according with the normal direction of a light emitting surface thereof, the following relation being satisfied:
• 1.1.times.n/(n.sup.2 -1).sup.1/2 .gtoreq.slope of asymptotic line
• .gtoreq.0.9.times.n/(n.sup.2 -1).sup.1/2
• where n is the refractive index of said lens elements layered on a light emitting surface of the light guiding member.

A surface light source comprising:

• a light guiding member made of a light transmitting plate;
• at least one linear light source arranged on at least one side edge of the light guiding member;
• at least one light reflecting layer disposed on the rear surface of the light guiding member;
• and
• a convex lenticular lens comprising:
• a light transmitting substrate having a first surface and a second surface opposite to said first surface;
• and
• a plurality of lens elements elongated on the first surface of said light transmitting substrate, having concave shaped cross sections, and defined in such a way that ridges thereof are aligned in parallel,
• wherein
• 30.degree..ltoreq..theta..sub.10% 100.degree. and R.ltoreq.20%,
• where .theta..sub.10% is a diffusing angle range with respect to normal of the first surface in the case that when light is entered from the second surface or first surface and transmitted from the first surface or second surface, the intensity of the light transmitted is equal to or more than 10% of the intensity of the light transmitted in a peak direction of a main lobe;
• and R is the ratio of side lobes to main lobe,
• wherein said lens elements have a hyperbolic shape and are defined in such a way that ridges thereof are aligned in parallel with each other, the longer axis direction of said lens elements according with the normal direction of a light emitting surface thereof, the following relation being satisfied:
• 1.1.times.n/(n.sup.2 -1).sup.1/2 .gtoreq.slope of asymptotic line
• .gtoreq.0.9.times.n/(n.sup.2 -1).sup.1/2
• where n is the refractive index of said lens elements layered on a light emitting surface of the light guiding member.

A surface light source comprising:

• a light guiding member made of a rectangular parallelpiped cavity;
• at least one linear light source arranged on at least one side edge of the light guiding member;
• at least one light reflecting layer disposed on the rear surface of the light guiding member;
• and
• a convex lenticular lens comprising:
• a light transmitting substrate having a first surface and a second surface opposite to said first surface;
• and
• a plurality of lens elements elongated on the first surface of said light transmitting substrate, having concave shaped cross sections, and defined in such a way that ridges thereof are aligned in parallel,
• wherein
• 30.degree..ltoreq..theta..sub.10% 100.degree. and R.ltoreq.20%,
• where .theta..sub.10% is a diffusing angle range with respect to normal of the first surface in the case that when light is entered from the second surface or first surface and transmitted from the first surface or second surface, the intensity of the light transmitted is equal to or more than 10% of the intensity of the light transmitted in a peak direction of a main lobe;
• and R is the ratio of side lobes to main lobe,
• wherein said lens elements have a hyperbolic shape and are defined in such a way that ridges thereof are aligned in parallel with each other, the longer axis direction of said lens elements according with the normal direction of a light emitting surface thereof, the following relation being satisfied:
• 1.1.times.n/(n.sup.2 -1).sup.1/2 .gtoreq.slope of asymptotic line
• .gtoreq.0.9.times.n/(n.sup.2 -1).sup.1/2
• where n is the refractive index of said lens elements layered on a light emitting surface of the light guiding member.

A surface light source comprising:

• a light guiding member made of a light transmitting plate;
• at least one point light source arranged on at least one side edge of the light guiding member;
• at least one light reflecting layer disposed on the rear surface of the light guiding member;
• and
• a convex lenticular lens comprising:
• a light transmitting substrate having a first surface and a second surface opposite to said first surface;
• and
• a plurality of lens elements elongated on the first surface of said light transmitting substrate, having concave shaped cross sections, and defined in such a way that ridges thereof are aligned in parallel,
• wherein
• 30.degree..ltoreq..theta..sub.10% 100.degree. and R.ltoreq.20%,
• where .theta..sub.10% is a diffusing angle range with respect to normal of the first surface in the case that when light is entered from the second surface or first surface and transmitted from the first surface or second surface, the intensity of the light transmitted is equal to or more than 10% of the intensity of the light transmitted in a peak direction of a main lobe;
• and R is the ratio of side lobes to main lobe,
• wherein said lens elements have a have a hyperbolic shape and are defined in such a way that ridges thereof are aligned in parallel with each other, the longer axis direction of said lens elements according with the normal direction of a light emitting surface thereof, the following relation being satisfied:
• 1.1.times.n/(n.sup.2 -1).sup.1/2 .gtoreq.slope of asymptotic line
• .gtoreq.0.9.times.n/(n.sup.2 -1).sup.1/2
• where n is the refractive index of said lens elements layered on a light emitting surface of the light guiding member.

A surface light source comprising:

• a light guiding member made of a light transmitting plate;
• at least one point light source arranged on at least one side edge of the light guiding member;
• at least one light reflecting layer disposed on the rear surface of the light guiding member;
• and
• a concave lenticular lens comprising:
• a light transmitting substrate having a first surface and a second surface opposite to said first surface;
• and
• a plurality of lens elements elongated on the first surface of said light transmitting substrate, having concave shaped cross sections, and defined in such a way that ridges thereof are aligned in parallel,
• wherein
• 30.degree..ltoreq..theta..sub.10% 100.degree. and R.ltoreq.20%,
• where .theta..sub.10% is a diffusing angle range with respect to normal of the first surface in the case that when light is entered from the second surface or first surface and transmitted from the first surface or second surface, the intensity of the light transmitted is equal to or more than 10% of the intensity of the light transmitted in a peak direction of a main lobe;
• and R is the ratio of side lobes to main lobe,
• wherein said lens elements have an elliptic shape and are defined in such a way that ridges thereof are aligned in parallel with each other, the longer axis direction of said lens elements according with the normal direction of a light emitting surface thereof, the cutting depth and the refractive index of said lens elements being given by:
• 1.40.ltoreq.refractive index.ltoreq.1.6,
• 1.20.ltoreq.length of longer axis/length of shorter axis.ltoreq.2.00, and
• 0.1.ltoreq.cutting depth/length of longer axis.ltoreq.0.50 layered on a light emitting surface of the light guiding member.

A surface light source comprising:

• a light guiding member made of a light transmitting plate;
• at least one linear light source arranged on at least one side edge of the light guiding member;
• at least one light reflecting layer disposed on the rear surface of the light guiding member;
• and
• a convex lenticular lens comprising:
• a light transmitting substrate having a first surface and a second surface opposite to said first surface;
• and
• a plurality of lens elements elongated on the first surface of said light transmitting substrate, having concave shaped cross sections, and defined in such a way that ridges thereof are aligned in parallel,
• wherein
• 30.degree..ltoreq..theta..sub.10% 100.degree. and R.ltoreq.20%,
• where .theta..sub.10% is a diffusing angle range with respect to normal of the first surface in the case that when light is entered from the second surface or first surface and transmitted from the first surface or second surface, the intensity of the light transmitted is equal to or more than 10% of the intensity of the light transmitted in a peak direction of a main lobe;
• and R is the ratio of side lobes to main lobe,
• wherein said lens elements have an elliptic shape and are defined in such a way that ridges thereof are aligned in parallel with each other, the longer axis direction of said lens elements according with the normal direction of a light emitting surface thereof, the cutting .depth and the refractive index of said lens elements being given by:
• 1.40.ltoreq.refractive index.ltoreq.1.6,
• 1.20.ltoreq.length of longer axis/length of shorter axis.ltoreq.2.00, and
• 0.1.ltoreq.cutting depth/length of longer axis.ltoreq.0.50 layered on a light emitting surface of the light guiding member.

A surface light source comprising:

• a light guiding member made of a rectangular parallelpiped cavity;
• at least one linear light source arranged on at least one side edge of the light guiding member;
• at least one light reflecting layer disposed on the rear surface of the light guiding member;
• and
• a convex lenticular lens comprising:
• a light transmitting substrate having a first surface and a second surface opposite to said first surface;
• and
• a plurality of lens elements elongated on the first surface of said light transmitting substrate, having concave shaped cross sections, and defined in such a way that ridges thereof are aligned in parallel,
• wherein
• 30.degree..ltoreq..theta..sub.10% 100.degree. and R.ltoreq.20%,
• where .theta..sub.10% is a diffusing angle range with respect to normal of the first surface in the case that when light is entered from the second surface or first surface and transmitted from the first surface or second surface, the intensity of the light transmitted is equal to or more than 10% of the intensity of the light transmitted in a peak direction of a main lobe;
• and R is the ratio of side lobes to main lobe,
• wherein said lens elements have an elliptic shape and are defined in such a way that ridges thereof are aligned in parallel with each other, the longer axis direction of said lens elements according with the normal direction of a light emitting surface thereof, the cutting depth and the refractive index of said lens elements being given by:
• 1.40.ltoreq.refractive index.ltoreq.1.6, layered on a light emitting surface of the light guiding member.

A surface light source comprising:

• a light guiding member made of a rectangular parallelpiped cavity;
• at least one point light source arranged on at least one side edge of the light guiding member;
• at least one light reflecting layer disposed on the rear surface of the light guiding member;
• and
• a convex lenticular lens comprising:
• a light transmitting substrate having a first surface and a second surface opposite to said first surface;
• and
• a plurality of lens elements elongated on the first surface of said light transmitting substrate, having concave shaped cross sections, and defined in such a way that ridges thereof are aligned in parallel,
• wherein
• 30.degree..ltoreq..theta..sub.10% 100.degree. and R.ltoreq.20%,
• where .theta..sub.10% is a diffusing angle range with respect to normal of the first surface in the case that when light is entered from the second surface or first surface and transmitted from the first surface or second surface, the intensity of the light transmitted is equal to or more than 10% of the intensity of the light transmitted in a peak direction of a main lobe;
• and R is the ratio of side lobes to main lobe,
• wherein said lens elements have an elliptic shape and are defined in such a way that ridges thereof are aligned in parallel with each other, the longer axis direction of said lens elements according with the normal direction of a light emitting surface thereof, the cutting depth and the refractive index of said lens elements being given by:
• 1.40.ltoreq.refractive index.ltoreq.1.6,
• 1.20.ltoreq.length of longer axis/length of shorter axis.ltoreq.2.00, and
• 0.1.ltoreq.cutting depth/length of longer axis.ltoreq.0.50 layered on a light emitting surface of the light guiding member.

A surface light source comprising:

• a light guiding member made of a light transmitting plate;
• at least one point light source arranged on at least one side edge of the light guiding member;
• at least one light reflecting layer disposed on the rear surface of the light guiding member;
• and
• a convex lenticular lens comprising:
• a light transmitting substrate having a first surface and a second surface opposite to said first surface;
• and
• a plurality of lens elements elongated on the first surface of said light transmitting substrate, having concave shaped cross sections, and defined in such a way that ridges thereof are aligned in parallel,
• wherein
• 30.degree..ltoreq..theta..sub.10% 100.degree. and R.ltoreq.20%,
• where .theta..sub.10% is a diffusing angle range with respect to normal of the first surface in the case that when light is entered from the second surface or first surface and transmitted from the first surface or second surface, the intensity of the light transmitted is equal to or more than 10% of the intensity of the light transmitted in a peak direction of a main lobe;
• and R is the ratio of side lobes to main lobe,
• wherein said lens elements have an elliptic shape and are defined in such a way that ridges thereof are aligned in parallel with each other, the longer axis direction of said lens elements according with the normal direction of a light emitting surface thereof, the cutting depth and the refractive index of said lens elements being given by:
• 1.40.ltoreq.refractive index.ltoreq.1.6,
• 1.20.ltoreq.length of longer axis/length of shorter axis.ltoreq.2.00, and
• 0.1.ltoreq.cutting depth/length of longer axis.ltoreq.0.50 layered on a light emitting surface of the light guiding member.

A surface light source comprising:

• a light guiding member made of a rectangular parallelpiped cavity;
• at least one linear light source arranged on at least one side edge of the light guiding member;
• at least one light reflecting layer disposed on the rear surface of the light guiding member;
• and
• a concave lenticular lens comprising:
• a light transmitting substrate having a first surface and a second surface opposite to said first surface;
• and
• a plurality of lens elements elongated on the first surface of said light transmitting substrate, having concave shaped cross sections, and defined in such a way that ridges thereof are aligned in parallel,
• wherein
• 30.degree..ltoreq..theta..sub.10% 100.degree. and R.ltoreq.20%
• where .theta..sub.10% is a diffusing angle range with respect to normal of the first surface in the case that when light is entered from the second surface or first surface and transmitted from the first surface or second surface, the intensity of the light transmitted is equal to or more than 10% of the intensity of the light transmitted in a peak direction of a main lobe;
• and R is the ratio of side lobes to main lobe,
• wherein said lens elements have an elliptic shape and are defined in such a way that ridges thereof are aligned in parallel with each other, the longer axis direction of said lens elements according with the normal direction of a light emitting surface thereof, the cutting depth and the refractive index of said lens elements being given by:
• 1.40.ltoreq.refractive index.ltoreq.1.6,
• 1.20.ltoreq.length of longer axis/length of shorter axis.ltoreq.2.00, and
• 0.1.ltoreq.cutting depth/length of longer axis.ltoreq.0.50 layered on a light emitting surface of the light guiding member.

A surface light source comprising:

• at least one point light source having a lower surface;
• a lamp house that covers the lower surface and side surface of the light source and has an opening on the upper surface of the light source and an inner reflecting surface;
• and
• a lenticular lens comprising:
• a light transmitting substrate having a first surface and a second surface opposite to said first surface;
• and
• a plurality of lens elements elongated on the first surface of said light transmitting substrate, having concave shaped cross sections, and defined in such a way that ridges thereof are aligned in parallel,
• wherein
• 30.degree..ltoreq..theta..sub.10% .ltoreq.100.degree. and R.ltoreq.20%,
• where .theta..sub.10% is a diffusing angle range with respect to normal of the first surface in the case that when light is entered from the second surface or first surface and transmitted from the first surface or second surface, the intensity of the light transmitted is equal to or more than 10% of the intensity of the light transmitted in a peak direction of a main lobe;
• and R is the ratio of side lobes to main lobe,
• wherein said lens elements have an elliptic shape and are defined in such a way that ridges thereof are aligned in parallel with each other, the longer axis direction of said lens elements according with the normal direction of a light emitting surface thereof, the following relation being satisfied:
• 1.1.times.n/(n.sup.2 -1).sup.1/2 .gtoreq.length of longer axis/length of shorter axis
• .gtoreq.0.9.times.n/(n.sup.2 -1).sup.1/2
• where n is the refractive index of said lens elements covering the opening of said lamp house.

A surface light source, comprising:

• at least one point light source having a lower surface;
• a lamp house that covers the lower surface and side surface of the light source and has an opening on the upper surface of the light source and an inner reflecting surface;
• and
• a lenticular lens comprising:
• a light transmitting substrate having a first surface and a second surface opposite to said first surface;
• and
• a plurality of lens elements elongated on the first surface of said light transmitting substrate having concave shaped cross sections, and defined in such a way that ridges thereof are aligned in parallel,
• wherein
• 30.degree..ltoreq..theta..sub.10% 100.degree. and R.ltoreq.20%,
• where .theta..sub.10% is a diffusing angle range with respect to normal of the first surface in the case that when light is entered from the second surface or first surface and transmitted from the first surface or second surface, the intensity of the light transmitted is equal to or more than 10% of the intensity of the light transmitted in a peak direction of a main lobe;
• and R is the ratio of side lobes to main lobe,
• wherein said lens elements have an elliptic shape and are defined in such a way that ridges thereof are aligned in parallel with each other, the longer axis direction of said lens elements according with the normal direction of a light emitting surface thereof, the cutting depth and the refractive index of said lens elements being given by:
• 1.40.ltoreq.refractive index.ltoreq.1.6,
• 1.20.ltoreq.length of longer axis/length of shorter axis.ltoreq.2.00, and
• 0.1.ltoreq.cutting depth/length of longer axis.ltoreq.0.50 covering the opening of said lamp house.