Double-sided lens sheet and projection screen
AssigneeToppan Printing Co., Ltd.
InventorsKazuyoshi Ebina, Takashi Abe, Masaru Miyashita, Susumu Takahashi
Life of this patent
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Abstract
In order to provide a dual-surface lens sheet in which a color shift is reduced and positions of unit lenses on a front surface and a back surface are easily aligned even if the unit lenses are disposed in fine pitch when used for a rear projection screen which is used for a display device using a plurality of projector as light sources, a half-column-cylindrical-convex-lens is used in a lens sheet having lens sections on front surface and a back surface such that pitch ratio for disposing the unit lenses on the front surface and the back surface is in a range of 1:2 to 1:30 and disposition directions of the lens sections are uniform.
Claims30
A dual-surface lens sheet having periodical gaps contained in a lens sections on a front surface and a back surface in a lens sheet wherein pitch ratio of the unit lens on the front surface and the back surface is in a range of 1:1 to 1:30.
A micro-lens sheet having a micro-lens array section in which unit lenses are disposed in approximate matrix in a second dimensional manner on at least one surface of a base board wherein
- diameter for each of the unit lens and the disposition pitch is 200 μm or shorter;
- light emission angle which is emitted from each unit lens is more than ±30 degrees against a normal of a main surface of the micro-lens sheet;
- chromatic difference of magnification which is caused by each unit lens is designed to be in a range of 0% <chromatic difference of magnification ≦50% of the diameter of the lens.
A projection screen having the micro-lens sheet having the micro-lens array section in which the unit lenses are disposed in an approximate matrix in a second-dimensional manner wherein
- a surface of the unit lens is formed in toric shape as a continuous surface such that curvature of cross sectional shape of the unit lens in one direction is smaller than that in an orthogonal direction to the particular direction;
- the micro-lens array section in which the unit lens is disposed in an approximate matrix in a second-dimension manner is formed on one surface of the transparent sheet;
- and
- the shading layer having the aperture section of which optical axis is aligned with the optical axis of unit lens group on a surface of the sheet which is disposed opposite to the micro-lens array section.
Dependencies are inferred from the claim text.