Rear projection type display system

• US 5,611,611 A
• Filed: 03/09/1995
• Issued: 03/18/1997
• Est. Priority Date: 10/05/1994
• Status: Expired due to Term

• Current Assignee: Hitachi Maxell Limited (Maxell, Ltd.)
• Original Assignee: Hitachi, Ltd.
• Inventors: Itoh, Takashi, Kamiya, Makoto, Sakamoto, Shuichi, Ogino, Masanori, Kuroda, Shoji, Iwahara, Yoshiaki
• Primary Examiner(s): DOWLING, WILLIAM C
• Application Number:
  US08/401,253
• Time in Patent Office: 740 Days
• Field of Search: 353/38, 353/74, 353/75, 353/76, 359/454-457, 348/744
• US Class Current: 353/74
• CPC Class Codes: G02B 3/0043 Inhomogeneous or irregular arrays, e.g. varying shape, size, height
• CPC Class Codes: G02B 3/005 arranged along a single direction only, e.g. lenticular sheets G02B3/0043 takes precedence
• CPC Class Codes: G02B 3/0062 Stacked lens arrays, i.e. refractive surfaces arranged in at least two planes, without structurally separate optical elements in-between
• CPC Class Codes: G02B 3/0068 arranged in a single integral body or plate, e.g. laminates or hybrid structures with other optical elements G02B5/1885, G02B17/002, G02B30/27 take precedence
• CPC Class Codes: G03B 21/625 Lenticular translucent screens

Abstract

A rear projection type display system with a transmissive screen. A transparent reinforcing plate is coupled to a lenticular sheet of the screen on the light output side by a connective member to broaden the horizontal diverging angle by 60 degrees or more to the right and left sides. The duty factor of a black stripe formed on the lenticular sheet is set to 60% or more so improve the contrast of an image. The diverging angle at each point of a vertically-diffusing lens for diverging light in the vertical direction is modulated in accordance with the height of each point to offer a proper visual angle range in the vertical direction.

Claims

1. A rear projection type display system comprising:

original image forming means;

projection lens means; and

transmissive type screen means,

said transmissive type screen means comprising at least a Fresnel sheet disposed on the light input side and a lenticular sheet disposed on the light output side,

wherein said lenticular sheet is formed with a vertical-stripe lenticular lens surface on the light input side, said lenticular lens surface diverging light in the horizontal direction, a light intercepting convex part of said lenticular sheet is printed with black stripes on the light output side, and the width of each black stripe is set to 60% or more of an array pitch of said lenticular lens surface,

and said transmissive type screen means further comprising transparent reinforcing plate means and transparent connective means,

wherein said connective means integrally connects said reinforcing plate means to a light transmissive concave part of said lenticular sheet on the light output side while removing any air layer, and the total thickness of said lenticular sheet and said reinforcing plate means is set to a width satisfying a self-weight buckling prevention condition.

2. A rear projection type display system according to claim 1, further comprising polarizer means for passing only horizontally polarized light components, said polarizer means being integrally formed with said reinforcing plate means on the light input side.

3. A rear projection type display system according to claim 1, further comprising flare preventing means, said flare preventing means including polarizer means and quarter wavelength plate means disposed between said projection lens means and said original image forming means, and the birefringence fundamental axis direction of said quarter wavelength plate means is tilted by about 45 degrees from the direction of polarized light passing through said polarizer means.

4. A rear projection type display system according to claim 1, wherein a vertically-diffusing lenticular lens means is formed on the light input side of said reinforcing means, said vertically-diffusing lenticular lens means being integrally formed with said transmissive type screen means so as not to expose the lens portion of said vertically-diffusing lenticular lens means to the air.

5. A rear projection type display system according to claim 2, wherein polarizer means for passing only vertically polarized light is disposed between a room illuminating light source and said transmissive type screen means.

6. A rear projection type display system comprising:

original image forming means;

projection lens means; and

transmissive type screen means,

said transmissive type screen means comprising at least a Fresnel sheet disposed on the light input side and a lenticular sheet disposed on the light output side,

wherein said lenticular sheet is formed with a vertical-stripe lenticular lens surface on the light input side, said lenticular lens surface diverging light in the horizontal direction, a light intercepting convex part of said lenticular sheet is printed with black stripes on the light output side,

said transmissive type screen means further comprising transparent reinforcing plate means and transparent connective means,

wherein said connective means integrally connects said reinforcing plate means to a light transmissive concave part of said lenticular sheet on the light output side while removing any air layer, and the total thickness of said lenticular sheet and said reinforcing plate means is set to a width satisfying a self-weight buckling prevention condition, and

said transmissive type screen means further comprising a vertical lenticular lens for diverging light in the vertical direction,

wherein said vertical lenticular lens is formed as pitch-modulated lenticular lens means, and the array pitch of said pitch-modulated lenticular lens means at the area where a broadest vertical diverging angle is required, is set to be 1.2 times or more of the array pitch at the area where a narrowest vertical diverging angle is required.

7. A rear projection type display system comprising:

original image forming means;

projection lens means;

transmissive type screen means; and

light density modulating means,

said transmissive type screen means comprising at least a Fresnel sheet, a horizontal lenticular lens for diverging light in the horizontal direction, and a vertical lenticular lens for diverging light in the vertical direction,

wherein said vertical lenticular lens is formed as pitch-modulated lenticular lens means, the array pitch of said pitch-modulated lenticular lens means at the area where a broadest vertical diverging angle is required, is set to be 1.2 times or more of the array pitch at the area where a narrowest vertical diverging angle is required, and said light density modulating means increases a light density of said image forming means at the area where the broadest vertical diverging angle is required, more than a light density at the area where the narrowest vertical diverging angle is required.

8. A rear projection type display system according to claim 7, wherein said light density modulating means is a gain controller for controlling the amplitude of an image signal.

9. A rear projection type display system according to claim 7, wherein said light density modulating means is one-dimensional meniscus lens means.