LCD including a diffusing screen in a plane where emerging light from one pixel abuts light from adjacent pixels

• US 5,504,602 A
• Filed: 10/08/1993
• Issued: 04/02/1996
• Est. Priority Date: 10/12/1992
• Status: Expired due to Term

• Current Assignee: Sharp Kabushiki Kaisha (Hon Hai Precision Industry Co., Ltd.)
• Original Assignee: Sharp Kabushiki Kaisha (Hon Hai Precision Industry Co., Ltd.)
• Inventors: Farmer, William J.
• Primary Examiner(s): Gross, Anita Pellman
• Assistant Examiner(s): TON, MINH TOAN T
• Application Number:
  US08/134,103
• Time in Patent Office: 907 Days
• Field of Search: 359/40, 359/41, 359/69, 359/62
• US Class Current: 349/112
• CPC Class Codes: G02F 1/133526 Lenses, e.g. microlenses or Fresnel lenses
• CPC Class Codes: G03H 1/02 Details of features involved during the holographic process; Replication of holograms without interference recording
• CPC Class Codes: G03H 1/268 Holographic stereogram
• CPC Class Codes: G03H 2001/0224 Active addressable light modulator, i.e. Spatial Light Modulator [SLM] corresponding details, see subgroups of G03H2225/00
• CPC Class Codes: G03H 2210/22 2D SLM object wherein the object beam is formed of the light modulated by the SLM SLM per se G03H2001/0224
• CPC Class Codes: G03H 2223/14 Diffuser, e.g. lens array, random phase mask
• CPC Class Codes: G03H 2223/19 Microoptic array, e.g. lens array
• CPC Class Codes: G03H 2225/55 Having optical element registered to each pixel

Abstract

A projection apparatus for holographic stereogram recording has a transmissive liquid crystal device and a diffusion screen. The transmissive liquid crystal device has a microlens array on its incident side and a polarizing sheet on its transmitting side. The microlenses are in one to one correspondence with the pixels of the liquid crystal device. The position of the diffusion screen is chosen such that the image transmitted to it from the liquid crystal device appears continuous.

Claims

1. An apparatus for use in holographic stereogram recording, comprising:

a transmissive liquid crystal device having

a microlens array disposed on an incident side of said transmissive liquid crystal device,

a liquid crystal layer, each pixel of which is provided with an entrance aperture and an exit aperture in such a manner that light from a microlens of said microlens array is made to run through the entrance aperture, focused in the pixel and made to diverge through the exit aperture and

a polarizing sheet disposed on a transmitting side of said liquid crystal device; and

a diffusing screen located in a plane where emerging light having diverged from a pixel through said polarizing sheet abuts light having diverged from adjacent pixels in such a manner that an image on said diffusing screen appears continuous without gridlike artifacts.

2. An apparatus according to claim 1, further comprising a second microlens array being disposed on the transmitting side of said liquid crystal device, wherein the respective focal lengths and separation of said two microlens arrays are carefully controlled such that the output light field of said second microlens array is collimated thereby allowing increased freedom of placement to said diffusing screen.

3. An apparatus according to claim 2, wherein gaps exist between adjacent microlenses of said microlens arrays and a third microlens array is positioned a carefully controlled distance in front of said diffusing screen to produce the continuous image.

4. An apparatus according to claim 1, in which a projection lens system is used to project and magnify the plane of the continuous image onto said diffusing screen.

5. An apparatus according to claim 2, wherein one or more lenses is/are used to magnify the output image is/are between a liquid crystal device section and a diffusing screen section of said apparatus.

6. An apparatus according to claim 3, wherein one or more lenses used to magnify the output image are located between said second microlens array of the liquid crystal device section and said third microlens array of the diffusing screen section of said apparatus.