Optical sheet, light-emitting device, and method for manufacturing optical sheet

A transparent sheet for use with a light emitting body with one of surfaces of the transparent sheet being adjacent to the light emitting body,

• wherein the other surface of the transparent sheet includes a plurality of minute regions δ, a largest inscribed circle of the minute regions δ having a diameter from 0.2 μm to 8.0 μm, one of the minute regions δ being adjoined by and surrounded by some other ones of the minute regions δ,
• respective ones of the plurality of minute regions δ have random heights within a range of 0 to d/2 relative to a predetermined reference plane parallel to the other surface or have random depths within a range of 0 to d/2 relative to the predetermined reference plane,
• the predetermined reference plane is equidistant from a highest one of the minute regions δ and a lowest one of the minute regions δ in terms of a direction perpendicular to the other surface,
• d is from 0.2 μm to 1.4 μm,
• the plurality of minute regions δ have a shape of a polygon in a plane of the other surface,
• the plurality of minute regions δ are arranged in the plane of the other surface along a first direction that is parallel to one side of the polygon, and
• ones of the plurality of minute regions δ adjoining each other along the first direction are at positions which are coincident with each other in terms of a second direction that is perpendicular to the first direction, and a pair of minute regions adjoining each other along the second direction are at positions which are shifted from each other in terms of the first direction.

A transparent sheet for use with a light emitting body with one of surfaces of the transparent sheet being adjacent to the light emitting body,

• wherein the other surface of the transparent sheet includes a plurality of minute regions δ, a largest inscribed circle of the minute regions δ having a diameter from 0.4 μm to 4.0 μm, one of the minute regions δ being adjoined by and surrounded by some other ones of the minute regions δ,
• the plurality of minute regions δ include a plurality of minute regions δ1 and a plurality of remaining minute regions δ2,
• the minute regions δ1 and the minute regions δ2 are configured to produce a phase difference of 180° between part of light perpendicularly impinging on the one surface which is transmitted through the minute regions δ1 and another part of the light perpendicularly impinging on the one surface which is transmitted through the minute regions δ2,
• the plurality of minute regions δ have a shape of a polygon in a plane of the other surface,
• the plurality of minute regions δ are arranged in the plane of the other surface along a first direction that is parallel to one side of the polygon, and
• ones of the plurality of minute regions δ adjoining each other along the first direction are at positions which are coincident with each other in terms of a second direction that is perpendicular to the first direction, and a pair of minute regions adjoining each other along the second direction are at positions which are shifted from each other in terms of the first direction.

A light emitting device, comprising a light emitting body and a transparent protection layer provided on a light emitting surface of the light emitting body,

• wherein the transparent protection layer has a surface which adjoins the light emitting surface and a surface opposite to the adjoining surface, the opposite surface including a plurality of minute regions δ, a largest inscribed circle of the minute regions δhaving a diameter from 0.2 μm to 8.0 μm, one of the minute regions δ being adjoined by and surrounded by some other ones of the minute regions δ,
• the plurality of minute regions δ include a plurality of minute regions δ1 which are randomly selected from the plurality of minute regions δ so as to constitute 40% to 98% of the minute regions δ and a plurality of minute regions δ2 which constitute the remaining portion of the minute regions δ,
• the minute regions δ1 are protruding above the other surface to a height of d/2 relative to a predetermined reference plane parallel to the other surface,
• the minute regions δ2 are receding below the other surface to a depth of d/2 relative to the predetermined reference plane,
• the predetermined reference plane is equidistant from the minute regions δ1 and the minute regions δ2 in terms of a direction perpendicular to the other surface,
• the light emitting body is configured to emit light whose center wavelength of an emission spectrum is λ,
• λ/6(n1−n0)<d<λ/(n1−n0) holds where n1 is a refractive index of the protection layer and n0 is a refractive index of a medium with which the protection layer is in contact at the opposite surface, n0 being smaller than n1,
• the plurality of minute regions δ have a shape of a polygon in a plane of the other surface,
• the plurality of minute regions δ are arranged in the plane of the other surface along a first direction that is parallel to one side of the polygon, and
• ones of the plurality of minute regions δ adjoining each other along the first direction are at positions which are coincident with each other in terms of a second direction that is perpendicular to the first direction, and a pair of minute regions adjoining each other along the second direction are at positions which are shifted from each other in terms of the first direction.

A light emitting device, comprising a light emitting body and a transparent protection layer provided on a light emitting surface of the light emitting body,

• wherein the transparent protection layer has a surface which adjoins the light emitting surface and a surface opposite to the adjoining surface, the opposite surface including a plurality of minute regions δ, a largest inscribed circle of the minute regions δ having a diameter from 0.2 μm to 8.0 μm, one of the minute regions δ being adjoined by and surrounded by some other ones of the minute regions δ,
• respective ones of the plurality of minute regions δ have random heights within a range of 0 to d/2 relative to a predetermined reference plane parallel to the other surface or have random depths within a range of 0 to d/2 relative to the predetermined reference plane,
• the predetermined reference plane is equidistant from a highest one of the minute regions δ and a lowest one of the minute regions δ in terms of a direction perpendicular to the other surface,
• the light emitting body is configured to emit light whose center wavelength of an emission spectrum is λ,
• λ/6(n1−n0)>d>λ/(n1−n0) holds where n1 is a refractive index of the protection layer and n0 is a refractive index of a medium with which the protection layer is in contact at the opposite surface, n0 being smaller than n1, and
• the plurality of minute regions δ have a shape of a polygon in a plane of the other surface,
• the plurality of minute regions δ are arranged in the plane of the other surface along a first direction that is parallel to one side of the polygon, and
• ones of the plurality of minute regions δ adjoining each other along the first direction are at positions which are coincident with each other in terms of a second direction that is perpendicular to the first direction, and a pair of minute regions adjoining each other along the second direction are at positions which are shifted from each other in terms of the first direction.

A light emitting device, comprising a light emitting body and a transparent protection layer provided on a light emitting surface of the light emitting body,

• wherein the transparent protection layer has a surface which adjoins the light emitting surface and a surface opposite to the adjoining surface, the opposite surface including a plurality of minute regions δ, a largest inscribed circle of the minute regions δ having a diameter from 0.4 μm to 4.0 μm, one of the minute regions δ being adjoined by and surrounded by some other ones of the minute regions δ,
• the plurality of minute regions δ include a plurality of minute regions δ1 and a plurality of remaining minute regions δ2,
• the minute regions δ1 and the minute regions δ2 are configured to produce a phase difference of 180° between part of light perpendicularly impinging on the one surface which is transmitted through the minute regions δ1 and another part of the light perpendicularly impinging on the one surface which is transmitted through the minute regions δ2, and
• the plurality of minute regions δ have a shape of a polygon in a plane of the other surface,
• the plurality of minute regions δ are arranged in the plane of the other surface along a first direction that is parallel to one side of the polygon, and
• ones of the plurality of minute regions δ adjoining each other along the first direction are at positions which are coincident with each other in terms of a second direction that is perpendicular to the first direction, and a pair of minute regions adjoining each other along the second direction are at positions which are shifted from each other in terms of the first direction.