Display panel and display device using the same

• US 6,218,679 B1
• Filed: 07/09/1999
• Issued: 04/17/2001
• Est. Priority Date: 12/01/1993
• Status: Expired due to Term

• Current Assignee: Godo Kaisha IP Bridge 1 (IP Bridge, Inc.)
• Original Assignee: Matsushita Electric Industrial Company Limited (Panasonic Holdings Corporation)
• Inventors: Takahara, Hiroshi, Sannohe, Shinya
• Primary Examiner(s): Abraham, Fetsum
• Application Number:
  US09/347,863
• Time in Patent Office: 648 Days
• Field of Search: 349/5, 349/88, 349/187, 349/183, 349/110, 349/111, 257/59, 257/72
• US Class Current: 257/59
• CPC Class Codes: G02F 1/133345 Insulating layers G02F1/1335, G02F1/1337, G02F1/135, G02F1/136 take precedence
• CPC Class Codes: G02F 1/1334 based on polymer dispersed liquid crystals, e.g. microencapsulated liquid crystals
• CPC Class Codes: G02F 1/133502 Antiglare, refractive index matching layers
• CPC Class Codes: G02F 1/133512 Light shielding layers, e.g. black matrix G02F1/136209 takes precedence
• CPC Class Codes: G02F 1/133526 Lenses, e.g. microlenses or Fresnel lenses
• CPC Class Codes: G02F 1/13394 spacers regularly patterned on the cell subtrate, e.g. walls, pillars G02F1/133377 takes precedence
• CPC Class Codes: G02F 2203/02 reflective
• CPC Class Codes: G02F 2203/055 wavelength filtering
• CPC Class Codes: G03B 21/006 using LCD's
• CPC Class Codes: G03B 21/10 Projectors with built-in or built-on screen
• CPC Class Codes: G03B 21/14 Details
• CPC Class Codes: H04N 9/3105 for displaying all colours simultaneously, e.g. by using two or more electronic spatial light modulators simultaneous projection in colour photography G03B33/10; beam splitting or combining systems per se G02B27/10

Abstract

A liquid crystal display panel includes a counter substrate having a counter electrode and a multi-layered dielectric film both formed thereon, and an array substrate formed with pixel electrodes and thin-film transistors serving as switching elements. A layer of polymer dispersed liquid crystal material containing a UV-curable resin component and a liquid crystal component is sandwiched and sealed between the counter and array substrates. A light shielding film is formed over each thin-film transistor. The multi-layered dielectric film is a laminated structure of alternating thin-films of SiO₂ and HfO₂. Since the multi-layered dielectric film is of a nature capable of transmitting UV-rays of light therethrough, the UV-curable resin component positioned underneath the multi-layered dielectric film can be cured during the manufacture. Also, since the multi-layered dielectric film is of a nature capable of reflecting light of a visible region, it serves as a black matrix, reflecting the visible light modulated by the display panel. Black beads are used to keep the film thickness of the liquid crystal layer at a predetermined value. Preferably, a dielectric thin-film having a relative dielectric constant smaller than that of the liquid crystal material is formed on signal lines for transmitting signals to the thin-film transistors, to thereby accomplish an electromagnetic shield. Where color filters are to be formed on the pixel electrodes, those color filters may be formed on the signal lines to accomplish the electromagnetic shield.

Claims

1. A display panel of an active matrix type which comprises:

a first substrate including a plurality of light-transmissive pixel electrodes in a matrix pattern forming a plurality of pixels respectively;

a plurality of switching elements, wherein each switching element corresponds to a respective one of the pixels;

a second substrate including a counter electrode;

a layer of liquid crystal material sandwiched between said first and second substrates;

a first light shielding film made of a metallic material and disposed around said pixel electrodes on said first substrate so as to overlay said pixel electrodes; and

a second light shielding film formed on said second substrate and having a light shielding region overlapping at least a portion of a light shielding region of said first light shielding film.

2. The display panel as claimed in claim 1, comprising a dielectric column disposed between neighboring pixel electrodes and having a film thickness substantially equal to the thickness of said layer of liquid crystal material.

3. A projection-type liquid crystal display device comprising:

a light generator operable to emit light;

a light modulator, including a first substrate formed with a plurality of pixel electrodes arranged in a matrix pattern forming a plurality of pixels, respectively, and a plurality of switching elements, each corresponding to a respective one of the pixels, for applying a signal to said pixel electrodes, respectively, a second substrate formed with a counter electrode, and a layer of liquid crystal material sandwiched between said first and second substrates, said light modulator being operable to modulate the light emitted by said light generator, said light modulator being an active matrix type;

a projector operable to project the light modulated by said light modulator;

a first light shielding film made of a metallic material and disposed around said pixel electrodes on said first substrate so as to overlay said pixel electrodes; and

a second light shielding film formed on said second substrate and having a light shielding region overlapping at least a portion of a light shielding region of said first light shielding film.

4. The projection-type liquid crystal display device as claimed in claim 3, wherein said light modulator includes a dielectric column disposed between neighboring pixel electrodes and having a film thickness substantially equal to the thickness of said layer of liquid crystal material.

5. The projection-type liquid crystal display device as claimed in claim 3, wherein in said light modulator, a video signal of a reverse polarity is applied to every other row of said pixel electrodes.

6. A projection-type liquid crystal display device comprising:

a light generator;

a light separator operable to separate light from said light generator into a plurality of optical paths of different wavelength ranges;

a light combiner, comprising a dichroic prism, operable to combine the plural optical paths into a single optical path;

a liquid crystal display panel of a transmissive type, having a light incident side, operable to modulate light traveling along each of the optical paths separated by said light separator;

a projector operable to project light modulated by said display panel;

an optical coupling layer optically coupling said display panel with said dichroic prism, said optical coupling layer having an index of refraction within the range of 1.38 to 1.55; and

a transparent plate, having a thickness, bonded to said light incident side of said liquid crystal display panel.

7. The projection-type liquid crystal display device as claimed in claim 6, wherein said liquid crystal display panel includes a layer of liquid crystal material, pixel electrodes, and a dielectric column, disposed between neighboring pixel electrodes, having a film thickness substantially equal to the thickness of said layer of liquid crystal material.

8. The projection-type liquid crystal display device as claimed in claim 6, wherein said liquid crystal display panel includes a plurality of pixel electrodes arranged in a matrix pattern, and a video signal of a reverse polarity is applied to every other row of said pixel electrodes.

9. A projection-type liquid crystal display device comprising:

a light generator;

a liquid crystal display panel having a light incident side, a light emitting side, and a plurality of pixels arranged in a matrix pattern, including first, second, and third pixels;

an array of micro-lenses arranged in a matrix pattern and disposed on said light incident side of said liquid crystal display panel, said micro-lenses corresponding to said first, second, and third pixels, respectively;

a light separator operable to separate light from said light generator into red, green, and blue optical paths and comprising a first mirror capable of reflecting red light, a second mirror capable of reflecting green light, and a third mirror capable of reflecting blue light, said first, second, and third mirrors arranged so as to cause respective light traveling along the red, green, and blue optical paths to impinge upon said pixels of said liquid crystal display panel at different respective incident angles after having been refracted by said micro-lenses, wherein said first, second, and third pixels are operable to modulate light on the red, green, and blue optical paths, respectively;

an optical coupling layer having an index of refraction within the range of 1.38 to 1.55;

a lens optically coupled with said light emitting side of said liquid crystal display panel through said optical coupling layer; and

a projector operable to project light modulated by said display panel.

10. The projection-type liquid crystal display device as claimed in claim 9, wherein said liquid crystal display panel includes a layer of liquid crystal material, and a dielectric column, disposed between neighboring pixel electrodes, having a film thickness substantially equal to the thickness of said layer of liquid crystal material.

11. The projection-type liquid crystal display device as claimed in claim 9, wherein in said liquid crystal display panel, a video signal of a reverse polarity is applied to every other row of said pixel electrodes.

12. A projection-type liquid crystal display device comprising:

a casing;

a light transmissive screen fitted in said casing;

a light generator, including an arc discharge lamp, arranged in said casing;

a liquid crystal display panel having a light incident side, a light emitting side, and a plurality of pixels arranged in a matrix pattern, including first, second, and third pixels;

an array of micro-lenses arranged in a matrix pattern and disposed on said light incident side of said liquid crystal display panel, said micro-lenses corresponding to said first, second, and third pixels, respectively;

a light separator operable to separate light from said arc discharge lamp into red, green, and blue optical paths, and comprising a first mirror capable of reflecting red light, a second mirror capable of reflecting green light, and a third mirror capable of reflecting blue light, said first, second, and third mirrors arranged so as to cause respective light traveling along the red, green, and blue optical paths to impinge upon said pixels of said liquid crystal panel at different respective angles after having been refracted by said micro-lenses, wherein said first, second, and third pixels are operable to modulate light on the red, green, and blue optical paths, respectively;

an optical coupling layer having an index of refraction within the range of 1.38 to 1.55;

a lens optically coupled with said light emitting side of said liquid crystal display panel through said optical coupling layer; and

a projector operable to project light modulated by said liquid crystal display panel.

13. The projection-type liquid crystal display device as claimed in claim 12, wherein said liquid crystal display panel includes a layer of liquid crystal material, and a dielectric column, disposed between neighboring pixel electrodes, having a film thickness substantially equal to the thickness of said layer of liquid crystal material.

14. The projection-type liquid crystal display device as claimed in claim 12, wherein in said liquid crystal display panel, a video signal of a reverse polarity is applied to every other row of said pixel electrodes.

15. A projection-type liquid crystal display device comprising:

a light generator;

a light separator operable to separate light from said light generator into red, green, and blue optical paths;

a first liquid crystal display panel having a light incident side, and a plurality of pixels disposed in a matrix pattern, and operable to modulate light traveling along the red optical path;

a second liquid crystal display panel having a light incident side, and a plurality of pixels disposed in a matrix pattern, and operable to modulate light traveling along the green optical path;

a third liquid crystal display panel having a light incident side, and a plurality of pixels disposed in a matrix pattern, and operable to modulate light traveling along the blue optical path;

a dichroic prism capable of, and arranged so as to, combine respective light modulated by said first, second, and third liquid crystal display panels into a single optical path;

an optical coupling layer having an index of refraction within the range of 1.38 to 1.55;

a projecting lens for projecting light combined by said dichroic prism; and

a transparent substrate having a thickness and disposed on, and optically coupled through said optical coupling layer with, said light incident side of said first, second, and third liquid crystal display panels.

16. The projection-type liquid crystal display device as claimed in claim 15, wherein at least one of said liquid crystal display panels includes a layer of liquid crystal material, and a dielectric column disposed between neighboring pixel electrodes and having a film thickness substantially equal to the thickness of said layer of liquid crystal material.

17. The projection-type liquid crystal display device as claimed in claim 15, wherein in at least one of said liquid crystal display panels, a video signal of a reverse polarity is applied to every other row of said pixel electrodes.

18. A projection-type display device comprising:

a light generator including an arc discharge lamp;

a light separator operable to separate light from said arc discharge lamp into a plurality of optical paths;

a liquid crystal display panel having a light exiting side and a plurality of pixels arranged in a matrix pattern, and operable to modulate respective light traveling along the plural optical paths;

a projector operable to project the light modulated by said liquid crystal display panel;

an optical coupling layer having an index of refraction within the range of 1.38 to 1.55;

a transparent substrate having a thickness and disposed on, and optically coupled through said optical coupling layer with, said light exiting side of said liquid crystal panel; and

a polarizing plate disposed on said light exiting side of said transparent substrate.

19. The projection-type liquid crystal display device as claimed in claim 18, wherein said liquid crystal display panel includes a layer of liquid crystal material, and a dielectric column disposed between neighboring pixel electrodes and having a film thickness substantially equal to the thickness of said layer of liquid crystal material.

20. The projection-type liquid crystal display device as claimed in claim 18, wherein in said liquid crystal display panel, a video signal of a reverse polarity is applied to every other row of said pixel electrodes.

21. A viewfinder for use by a viewer, said viewfinder comprising:

a light emitting diode;

a liquid crystal panel having a plurality of pixels arranged in a matrix pattern, and operable to modulate light emitted from said light emitting diode;

an illuminating lens situated to collect light emitted from said light emitting diode and to illuminate said liquid crystal panel;

an image magnifying lens situated to magnify an optical image of said liquid crystal panel so that the viewer can view the optical image on an enlarged scale;

an eyepiece ring supporting said image magnifying lens;

a first member supporting said light emitting diode; and

a second member retaining said eyepiece ring;

wherein a distance between said light emitting diode and said magnifying lens is adjustable.

22. The viewfinder as claimed in claim 21, wherein said illuminating lens has a surface of a relatively large radius of curvature and is positioned with such surface oriented towards said light emitting diode.

23. A video camera comprising said viewfinder of claim 21.