Large-screen projection type display
AssigneeHitachi, Ltd.
InventorMasanori Ogino
Life of this patent
Estimating the term…
Abstract
It is an object of the invention to provide a large-screen projection type display capable of reducing the moire interference due to the periodical structure of the linear Fresnel lenses and lenticular lenses. Since the moire interference is attributed to the shades S generated from the Fresnel sheet 1, these shades are diverged at a divergence angle .epsilon. by the action of the small-pitch lenticular lenses 4, so that the shades can be eliminated on the light-incident side surface of the lenticular sheet 3 which is located at a distance D from behind the Fresnel sheet.
Claims30
A large-screen projection-type display using a transmission type screen, said transmission type screen comprising at least:
- a first sheet transparent to light from a projection source;
- a second sheet which is provided on the viewer's side of said first sheet and which is transparent to light from said first sheet;
- and a third sheet which is located on the viewer's side of said second sheet and which is transparent to light from said second sheet, said first sheet having first divergence means for diverging light at least in the horizontal direction and Fresnel lenses for converging light at least in the horizontal direction, said third sheet having first lenticular lenses of a relatively large pitch, an effective divergence angle .epsilon. of said first divergence means, an arrangement period T.sub.F of said Fresnel lens, and a thickness D of said second sheet have a relation given by
- .epsilon.D/T.sub.F .gtoreq.0.7
A large-screen projection-type display using a transmission type screen, said transmission type screen comprising at least:
- a first sheet transparent to light from a projection source;
- a second sheet which is provided on the viewer's side of said first sheet and which is transparent to light from said first sheet;
- and a third sheet which is located on the viewer's side of said second sheet and which is transparent to light from said second sheet, said first sheet having first lenticular Fresnel lenses for diverging light at least in the horizontal direction and converging light at least in the horizontal direction, said third sheet having third lenticular lenses of a relatively large pitch, an effective divergence angle .epsilon. of a lenticular component of said first lenticular Fresnel lenses, an arrangement period T.sub.F of Fresnel components of said first lenticular Fresnel lenses, and a thickness D of said second sheet have a relation given by
- .epsilon.D/T.sub.F.gtoreq. 0.7
A large-screen projection-type display comprising:
- divergence means for diverging light at least in the horizontal direction;
- Fresnel lens means for converging light at least in the horizontal direction;
- means for forming a thickness;
- and
- horizontal lenticular lens means for diverging light in the horizontal direction,
- wherein said divergence means and said Fresnel lens means are located on the light-incident side of said thickness-forming means, said thickness-forming means is located on the light-incident side of said horizontal lenticular lens means, and an effective divergence angle .epsilon. of said divergence means, an arrangement period T.sub.F of a Fresnel lenses of said Fresnel lens means, and a thickness D of said thickness-forming means have the following relation:
- .epsilon.D/T.sub.F .gtoreq.0.7
Dependencies are inferred from the claim text.