Projection type display apparatus

• US 5,315,330 A
• Filed: 09/22/1993
• Issued: 05/24/1994
• Est. Priority Date: 12/21/1989
• 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: Hamada, Hiroshi
• Primary Examiner(s): Cuchlinski, Jr., William A.
• Assistant Examiner(s): Dowling, William C.
• Application Number:
  US08/124,431
• Time in Patent Office: 244 Days
• Field of Search: 353/30, 353/31, 353/122, 353/102, 353/DIG. 3, 359/36, 359/40, 359/41, 359/48, 359/54, 359/55
• US Class Current: 353/31
• CPC Class Codes: H04N 9/3108 by using a single electronic spatial light modulator

Abstract

A projection type image display apparatus which includes a light source, a first optical means situated along an optical path between the light source and the transmissive display device so as to converge the light rays from the light source and enable the principal light rays to enter the transmissive display device in parallel with each other, a second optical means disposed on an opposite side to the light source with respect to the transmissive display device so as to converge the light rays from the transmissive display device, and a third optical means disposed near a rear focus of the second optical means so as to project a transmitted light image on a screen.

Claims

1. A projection type image display apparatus which displays an image picture on a screen by projecting light rays, the display apparatus comprising a transmissive display device, a light source, a first optical means situated along an optical axis between the light source and the transmissive display device so as to project the light rays from the light source and enable the principle light rays to enter the transmissive display device in parallel along the optical axis, a second optical means disposed on an opposite side to the light source with respect to the transmissive display device so as to project the light rays from the transmissive display device, and a third optical means disposed near a rear focus of the second optical means so as to project a transmitted light image through the display device on a screen, the transmissive display device comprising a pair of simple matrix liquid cells multi-layered in a direction in which light rays are passed, each of the simple matrix liquid cells being provided with scanning lines on its inner surface of the substrate so that the scanning lines of each cell are staggered with respect to each other, the scanning lines being arranged at predetermined pitches such that the width of the pitches is larger than an out-of-focus distance determined by the product of the degree of parallelism of the first optical means and the total optical thickness of the two substrates of the pair of matrix cells.

2. A projection type image display apparatus which displays an image on a screen by projecting light rays, the display apparatus comprising:

a transmissive display device including three display cells multi-layered in a direction in which light rays are passed through the device;

a light source;

a first optical means situated along an optical axis between the light source and the transmissive display device so as to project the light rays from the light source and enable the principle light rays to enter the transmissive display device in parallel along the optical axis;

a second optical means disposed on an opposite side to the light source with respect to the transmissive display device so as to project the light rays from the transmissive display device; and

a third optical means so as to project a transmitted light image through the display device on a screen,

wherein a middle one of the three display cells contains magenta pigment for controlling a green light component, the image display apparatus being focussed in the middle display cell, thereby intensifying a visual resolving power of a human eye for image displayed on the screen.

3. A projection type image display apparatus which displays an image on a screen by projecting light rays, the display apparatus comprising:

a transmissive display device comprising an array of pixels provided by a plurality of display cells multi-layered in a direction in which light rays are passed through the device, each display cell comprising two substrates disposed on respective sides of a display plane of the cell;

a light source;

a first optical means situated along an optical axis between the light source and the transmissive display device so as to project the light rays from the light source and enable the principle light rays to enter the transmissive display device in parallel along the optical axis;

a second optical means disposed on an opposite side to the light source with respect to the transmissive display device so as to project the light rays from the transmissive display device; and

a third optical means so as to project an image transmitted through the display device on a screen,

wherein a degree of out-of-focus (OFD) is equal to or smaller than a pitch of the pixels of the transmissive display device, the degree of out-of-focus being defined by;

space="preserve" listing-type="equation">OFD=(T/n)×

[(D4/2)/f]

where T is a thickness or a total thickness of the substrate or substrates of the transmissive display device between a focal plane by the third optical means in the display device and the display plane of each display cell, n is a refractive index of the substrate or substrates, D4 is a diameter of an illuminating section of the light source, and f is a focal length of the first optical means.

4. A projection type image display apparatus according to claim 3, wherein the display cells are simple matrix liquid crystal cells, each of the simple matrix liquid crystal cells being provided with scanning lines, the scanning lines of each cell being staggered with respect to each other.

5. A projection type image display apparatus according to claim 3, wherein the display cells are active matrix liquid crystal cells, each of the active matrix liquid crystal cells being provided with picture element electrodes as display electrodes.

6. A projection type image display apparatus according to claim 3, wherein the transmissive display device comprises three display cells multi-layered in direction in which light rays are passed.

7. A projection type image display apparatus according to claim 6, wherein the display cells change the transmission of light components corresponding to cyan, magenta and yellow, respectively.

8. A projection type image display apparatus according to claim 7, wherein the display cells are Guest Host Mode liquid crystal cells.