Screen, a fresnel lens sheet used for the screen, and an image display apparatus using the screen

A screen having a Fresnel lens sheet, on which light from a picture source is projected, the Fresnel lens sheet comprising:

• a total reflection prism portion formed on a side of the Fresnel lens sheet toward the picture source;
• and
• a refractive prism portion formed on a picture seen side of the Fresnel lens;
• and
• wherein the total reflection prism portion includes a first total reflection prism portion, which is formed in that region on the side of the Fresnel lens sheet toward the picture source, on which the light is incident at a predetermined incident angle or more, and by which at least the light is reflected to a first direction substantially perpendicular to the Fresnel lens sheet to outgo, and
• a second total reflection prism portion, by which the light is reflected to a second direction toward an optic axial center of the Fresnel lens sheet to outgo, and
• the refractive prism portion includes a first refractive prism portion having a first refractive surface, which is formed in a region disposed on the picture seen side of the Fresnel lens sheet and opposed to that region, in which at least the total reflection prism portion is not formed, and by which the light is refracted to outgo toward the picture seen side, and
• a second refractive prism portion having a second refractive surface, by which light outgoing from the second total reflection prism portion to be directed to the second direction is refracted to the first direction to outgo.

A screen having a Fresnel lens sheet, on which light from a picture source is projected, the Fresnel lens sheet comprising:

• a total reflection prism formed on a side of the Fresnel lens sheet toward the picture source;
• and
• a first refractive prism portion formed on a picture seen side of the Fresnel lens sheet;
• and
• wherein the total reflection prism portion is formed in that region on the side of the Fresnel lens sheet toward the picture source, on which the light is incident at a predetermined incident angle or more,
• the first refractive prism portion includes a first refractive surface, which is formed in a region disposed on the picture seen side of the Fresnel lens sheet and opposed to that region, in which the total reflection prism portion is not formed, and by which the light is refracted to outgo toward the picture seen side,
• the total reflection prism portion includes a first total reflection prism portion, by which at least the light is reflected to a first direction substantially perpendicular to the Fresnel lens sheet to outgo, and
• a second total reflection prism portion, by which the light is reflected to a second direction toward an optic axial center of the Fresnel lens sheet to outgo,
• a second refractive prism portion is provided on the picture seen side of the Fresnel lens sheet to include a second refractive surface, by which light outgoing from the second total reflection prism portion to be directed to the second direction is refracted to the first direction to outgo, and
• a third refractive prism portion is provided between the second refractive prism portion and the first refractive prism portion to include at least a surface having substantially the same prism angle as that of the second refractive prism portion and a surface having substantially the same prism angle as that of the first refractive prism portion.

A image display apparatus comprising:

• a picture source;
• an optical part that enlarges and projects an image of the picture source;
• a transmissive screen, on which a projected image projected from the optical part is thrown;
• and
• wherein the transmissive screen comprises a Fresnel lens sheet and a diffusion sheet arranged on a picture seen side of the Fresnel lens sheet to diffuse an image light at least in a horizontal direction on a screen plane,
• a first total reflection prism portion, by which light incident at a first incident angle range is reflected to a first direction substantially perpendicular to the Fresnel lens sheet to outgo, and a second total reflection prism portion, by which light incident at a second incident angle range smaller than the first incident angle range is reflected to a second direction toward an optic axial center of the Fresnel lens sheet to outgo, are provided on a side of the Fresnel lens sheet toward the picture source, and
• a first refractive prism portion, by which at least light of a smaller incident angle than the second incident angle range is refracted to outgo in the first direction, and a second refractive prism portion, by which light outgoing from the second total reflection prism portion to be directed in the second direction is refracted in the first direction to outgo, are provided on a picture seen side of the Fresnel lens sheet.