Projection-type liquid crystal display apparatus

• US 5,172,254 A
• Filed: 12/05/1989
• Issued: 12/15/1992
• Est. Priority Date: 12/05/1988
• 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: Atarashi, Hisashi, Takafuji, Yutaka
• Primary Examiner(s): Hille, Rolf
• Assistant Examiner(s): Ho, Tan
• Application Number:
  US07/446,304
• Time in Patent Office: 1,106 Days
• Field of Search: 353/20, 353/31, 353/33, 353/122, 359/40, 359/41, 359/48, 359/66, 359/68, 359/70, 359/106, 358/60, 358/61, 358/231, 358/232
• US Class Current: 349/9
• CPC Class Codes: H04N 9/3167 for polarizing the light beam polarizing optical systems per se G02B27/28

Abstract

A projection-type liquid crystal display apparatus uses liquid crystal cells as light polarizing devices. This apparatus makes a polarization control of one of the two linearly polarized light components perpendicular to each other separated by the polarizing light separating device through the first liquid crystal cell and of the other of the two through the second liquid crystal cell. The liquid crystal cells directly transmit through, a linearly polarized light component incident upon pixel portions corresponding to bright pixels of an image to be projected on the screen. Further they transmit through the one incident upon pixel portions corresponding to dark pixels of the image by converting it into the other linearly polarized light component. This apparatus composes the first linearly polarized light transmitted through pixel portions of the first liquid crystal cell corresponding to bright pixels of the image and the second linearly polarized light transmitted through pixel portions of the second liquid crystal cell corresponding to the same bright pixels as the above-mentioned bright pixels through a polarized light composing device, and projects the composed light onto a screen through an optical device.

Claims

1. A projection-type liquid crystal display apparatus comprising:

means for separating a light emitted from a light source into first and second linearly polarized light components perpendicular to each other;

a first liquid crystal cell, including a plurality of pixels, for transmitting light of the first linearly polarized light component incident upon a pixel containing a first type of display data from a first and second type of display data indicating light to be transmitted and nontransmitted, respectively, and for converting light of the first linearly polarized light component incident upon pixels containing a pixel corresponding to said second type of display data into light of the second linearly polarized light component;

a second liquid crystal cell, including a plurality of pixels each containing a pixel corresponding to the first or second type of display data, for transmitting light of the second linearly polarized light component incident upon a pixel containing the first type of display data and for converting light of the second linearly polarized light component incident upon a pixel containing said second type of display data into light of the first linearly polarized light component;

means for composing the first and second linearly polarized light components transmitted through each pixel to produce an image superposed from image data generated by said first and second liquid crystal cells; and

optical means for projecting the composed light onto a screen.

2. The projection-type liquid crystal display apparatus according to claim 1, wherein said first and second liquid crystal cells are twisted-nematic liquid crystal cells.

3. The projection-type liquid crystal display apparatus according to claim 1, wherein said first and second liquid crystal cells include color filters.

4. The projection-type liquid crystal display apparatus according to claim 3, wherein said first and second liquid crystal cells respectively include three liquid crystals cells, each of which corresponds to one incident primary color light of the respective first and second linearly polarized light components, separated into three primary colors.

5. The projection-type liquid crystal display apparatus according to claim 4, wherein the first and second linearly polarized light components are separated into the three primary colors through dichroic mirrors.

6. The projection-type liquid crystal display apparatus according to claim 1, wherein said first and second liquid crystal cells are connected to means to give the transmitted light a variable tone.

7. The projection-type liquid crystal display apparatus according to claim 1, wherein said polarized light composing means is a polarizing light beam splitter which composes the first linearly polarized light component transmitted through said first liquid crystal cell and said second linearly polarized light component transmitted through the second liquid crystal cell.

8. The projection-type liquid crystal display apparatus according to claim 1, wherein said polarized light composing means is a polarizing light beam splitter which composes the second linearly polarized light component transmitted through said first liquid crystal cell and the first linearly polarized light component transmitted through said second liquid crystal cell.

9. The projection-type liquid crystal display apparatus according to claim 7 or 8, wherein said polarizing light beam splitter is of plate type.

10. The projection-type liquid crystal display apparatus according to claim 7 or 8, wherein said polarizing light beam splitter is of cube type.

11. The projection-type liquid crystal display apparatus according to claim 1, wherein said optical means is a projection lens.

12. The projection-type liquid crystal display apparatus according to claim 1, wherein said screen is of non-transparent type.

13. The projection-type liquid crystal display apparatus according to claim 1, wherein said screen is of transparent type.

14. A projection display apparatus, comprising:

a light source for producing light;

light separating means for separating said produced light into light of a first linearly polarized light component and light of a second linearly polarized light component, perpendicular to said first linearly polarized light component;

first image forming means, formed of plural pixels, for receiving said separated light of said first linearly polarized light component and for transmitting an input image on said separated light of said first linearly polarized light component by applying a voltage to each pixel to produce a converted second linearly polarized light component;

second image forming means, formed of a plurality of pixels, for receiving said separated light of said second linearly polarized light component and for transmitting an input image on said separated light of said second linearly polarized light component by applying the voltage to each pixel to produce a converted first linearly polarized light component; and

combining means for combining said transmitted light of said converted first and second linearly polarized light components for projection of the input image to a display medium.

15. The projection display apparatus of claim 14, further comprising:

optical projection means for projecting said combined transmitted light of said converted first and second linearly polarized light components, to said display medium.

16. The projection display apparatus of claim 14, wherein said first and second image forming means are liquid crystal display cells, each including the plurality of pixels formed in a matrix.

17. The projection display apparatus of claim 16 wherein voltage is applied to pixels of said first and second liquid crystal display cells to form the input image on said first and second liquid crystal display cells, to be transmitted on said separated light of said first and second linearly polarized light components, respectively.

18. The projection display apparatus of claim 17, wherein said light of said first and second linearly polarized light components is transmitted through pixels corresponding to said input image, of said first and second liquid crystal display cells, respectively, and light of said first and second linearly polarized light components is converted to light of said second and first linearly polarized light components, respectively, through pixels not corresponding to said input image.

19. The projection display apparatus of claim 14, further comprising:

a plurality of light color separating means for separating said light of said first and second linearly polarized light components into light of red (r), green (g) and blue (b) color components,

wherein said first and second image forming means includes a plurality of subimage forming means, one corresponding to each of said r, g, b light color components, each for receiving one of said r, g, b light color components of said first and second linearly polarized light components, respectively, and for transmitting a color component of said input image on respective ones of said first and second linearly polarized light components, and

wherein said combining means includes a plurality of subcombining means, each for combining said r, g, b light color components into transmitted light of one of said first and second linearly polarized light components, to be combined for projection of said input image to a display medium.

20. A method of display, comprising the steps of:

a) producing light from a light source;

b) separating the produced light into light of a first linearly polarized light component and light of a second linearly polarized light component, perpendicular to the first linearly polarized light component;

c) forming an input image on a first image forming device;

d) transmitting the separated light of the first linearly polarized light component through the first image forming device and forming the input image on the separated light of the first linearly polarized light component;

e) forming the input image on a second image forming device;

f) transmitting the separated light of the second linearly polarized light component through the second image forming device and forming the input image on the separated light of the second linearly polarized light component; and

g) combining the transmitted light of the first and second linearly polarized light components for projection of the input image to a display medium.

21. The method of display as claimed in claim 20, further comprising the step of:

h) projecting the combined, transmitted light of the first and second light components, to the display medium.

22. The method of display as claimed in claim 20, wherein step (b) comprises the substeps of:

(1) separating the light of the first linearly polarized light component into each of a red (r), blue (b), and green (g) color component, and

(2) separating the light of the second linearly polarized light component into each of a red (r), blue (b), and green (g) color component,

step (c) comprises the substeps of,

(1) forming a red input subimage on a first subimage forming device,

(2) forming a blue input subimage on a second subimage forming device, and

(3) forming a green input subimage on a third subimage forming device,

step (e) comprises the substeps of,

(1) forming a red input subimage on a fourth subimage forming device,

(2) forming a blue input subimage on a fifth subimage forming device, and

(3) forming a green input subimage on a sixth subimage forming device,

step (d) comprises the substeps of,

(1) transmitting the separated red light of the first linearly polarized light component through the first subimage forming device and forming the red input subimage on the separated red light of the first linearly polarized light component,

(2) transmitting the separated blue light of the first linearly polarized light component through the second subimage forming device and forming the blue input subimage on the separated blue light of the first linearly polarized light component, and

(3) transmitting the separated green light of the first linearly polarized light component through the third subimage forming device and forming the green input subimage on the separated green light of the first linearly polarized light component,

step (f) comprises the substeps of

(1) transmitting the separated red light of the second linearly polarized light component through the fourth subimage forming device and forming the red input subimage on the separated red light of the second linearly polarized light component,

(2) transmitting the separated blue light of the second linearly polarized light component through the fifth subimage forming device and forming the blue input subimage on the separated blue light of the second linearly polarized light component, and

(3) transmitting the separated green light of the second linearly polarized light component through the sixth subimage forming device and forming the green input subimage on the separated green light of the second linearly polarized light component, and

step (g) includes the substeps of

(1) combining the red, green, and blue subimages on the separated red, green and blue light of the first linearly polarized light component,

(2) combining the red, green, and blue subimages on the separated red, green, and blue light of the second linearly polarized light component, and

(3) combining the combined transmitted light of the first and second linearly polarized light components, for projection of the input image to a display medium.

23. The method of display of claim 22, further comprising the step of:

(h) projecting the combined transmitted light of the first and second linearly polarized light components, to the display medium.

24. A projection display apparatus, comprising:

a light source for producing light;

light separating means for separating said produced light into light of a first linearly polarized light component and light of a second linearly polarized light component, perpendicular to said first linearly polarized light component;

first image forming means, including first color filter means formed on an incident face thereof, for receiving said separated light of said first linearly polarized light component and for transmitting a colored input image on said separated light of said first linearly polarized light component;

second image forming means, including second color filter means formed on an incident face thereof, for receiving said separated light of said second linearly polarized light component and for transmitting a colored input image on said separated light of said second linearly polarized light component; and

combining means for combining said transmitted light of said first and second linearly polarized light components for projection of the colored input image to a display medium.

25. The projection display apparatus of claim 24, further comprising:

optical projection means for projecting said combined, transmitted light of the first and second linearly polarized light components, to said display medium.

26. The projection display apparatus of claim 24, wherein said first and second image forming means are liquid crystal display cells, each including a plurality of pixels formed in a matrix.

27. The projection display apparatus of claim 26, wherein voltage is applied to pixels of said first and second liquid crystal display cells to form an input image corresponding to the colored input image, on the first and second liquid crystal display cells, to be transmitted on said separated light of said first and second linearly polarized light components, respectively.

28. The projection display apparatus of claim 24, further comprising first and second convex lenses, disposed between said light separating means and said first and second color filter means, for respectively condensing said first and second linearly polarized light components onto said first and second color filter means.

29. A projection display apparatus, comprising:

a light source for producing light;

light separating means for separating said produced light into light of a first linearly polarized light component and light of a second linearly polarized light component, perpendicular to said first linearly polarized light component;

first image forming means for receiving said separated light of said first linearly polarized light component and for transmitting a colored input image on said separated light of said first linearly polarized light component;

second image forming means for receiving said separated light of said second linearly polarized light component and for transmitting a colored input image on said separated light of said second linearly polarized light component; and

combining means for combining said transmitted light of said first and second linearly polarized light components for projection of the colored input image to a display medium,

said first and second image forming means each including

a plurality of light color separating means for separating said light of said first and second linearly polarized light components into light of red (r), green (g) and blue (b) components,

a plurality of sub-image forming means, one corresponding to each of said r, g, b light color components, each for receiving one of said r, g, b light color components of said first and second linearly polarized light components, respectively, and for transmitting a color component of said input image on respective ones of said first and second linearly polarized light components, and

sub-combining means for combining said r, g, b color components into transmitted light of one of said first and second linearly polarized light components, respectively.