Transparent projection screen with Fresnel structure and projection system using the same
AssigneeTD Electrooptic Films (TDEF) Inc.
InventorsJun Ma, Jiuzhi Xue
Life of this patent
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Abstract
The present invention relates to a transparent projection screen having a Fresnel structure. The projection screen is provided with Fresnel structure units having a specific structure, such that incident light irradiated to each Fresnel structure unit can be corrected by a Fresnel microstructure at this position and is reflected in the direction of an observer within a certain visible range, thereby improving the display uniformity of the transparent projection screen, and also reducing the interference of external ambient light on the transparent projection screen, such that a projection system using the transparent projection screen has a good viewing effect.
Claims18
A projection system, comprising a projector and a transparent projection screen, the transparent projection screen comprising:
- a substrate layer having a first surface and a second surface opposite to each other in parallel;
- a Fresnel structural layer comprising a plurality of Fresnel structural units formed on the first surface of the substrate layer, wherein the plurality of Fresnel structural units is arranged to form a plurality of concentric arcs having a common circle center, each of the Fresnel structural units comprises a first side surface close to the common circle center, a second side surface away from the common circle center, and a bottom surface parallel to the first surface of the substrate layer, a plurality of the first side surfaces and a plurality of the second side surfaces form a first surface of the Fresnel structural layer, a plurality of the bottom surfaces form a second surface of the Fresnel structural layer, a cross-section of each of the Fresnel structural units comprises a line a, a line b, and a line c that mutually intersect, a tangent line at any point on the line b makes an angle β1>60° with the line c, and the Fresnel structural layer has a first refractive index n1;
- a display layer having a first surface and a second surface opposite to each other, wherein the second surface of the display layer is disposed on and substantially conformal to the first surface of the Fresnel structural layer, such that the display layer forms a structure substantially identical to the first surface of the Fresnel structural layer, and the display layer has a second refractive index n2;
- and
- a refractive index matching layer having a first surface and a second surface opposite to each other, wherein the second surface of the refractive index matching layer is disposed on and conformal to the first surface of the display layer, the first surface of the refractive index matching layer is a surface parallel to the second surface of the substrate layer, and the refractive index matching layer has a third refractive index n3,
- wherein the first refractive index n1 is substantially the same as the third refractive index n3, and
- wherein the projector is disposed perpendicular to a plane where the transparent projection screen is located and in the same straight line as the common circle center.
Dependencies are inferred from the claim text.