Liquid crystal display with band-pass filter

• US 6,646,699 B2
• Filed: 09/20/2001
• Issued: 11/11/2003
• Est. Priority Date: 02/09/2001
• Status: Expired due to Term

• Current Assignee: Panasonic Liquid Crystal Display Company Limited (Panasonic Holdings Corporation)
• Original Assignee: Hitachi, Ltd.
• Inventors: Komura, Shinichi, Kondo, Katsumi, Utsumi, Yuka, Hiyama, Ikuo
• Primary Examiner(s): Chowdhury, Tarifur R.
• Application Number:
  US09/956,138
• Publication Number:
  US 20020109809A1
• Time in Patent Office: 782 Days
• Field of Search: 349/104, 349/141, 349/62, 349/65, 349/70
• US Class Current: 349/104
• CPC Class Codes: G02F 1/133509 Filters, e.g. light shielding masks
• CPC Class Codes: G02F 1/133514 Colour filters

Abstract

A liquid crystal display for displaying an image to be visible for a viewer, has a liquid crystal, a pair of electrodes for controlling an orientation of at least a part of the liquid crystal in accordance with an electric field between the electrodes, a light source for generating a light to be transmitted through the liquid crystal to the viewer, a pair of first and second polarizer plates, the first polarizer plate being arranged between the liquid crystal and the light source, and the second polarizer plate being arranged between the liquid crystal and the viewer, and a band-pass filter for absorbing a component of the light, a wave-length of which component is not more than 440 nm, and the band-pass filter being arranged between the light source and the viewer.

Claims

1. A liquid crystal display for displaying an image to be visible for a viewer, comprising:

a liquid crystal;

a pair of electrodes for controlling an orientation of at least a part of the liquid crystal in accordance with an electric field between the electrodes;

a light source for generating a light to be transmitted through the liquid crystal to the viewer;

a pair of first and second polarizer plates, the first polarizer plate being arranged between the liquid crystal and the light source, and the second polarizer plate being arranged between the liquid crystal and the viewer; and

a band-pass filter for absorbing a component of the light, a wave-length of which component is not more than 440 nm, and the band-pass filter being arranged between the light source and the viewer;

wherein a permeability of the band-pass filter for the component of wave-length not more than 440 nm is smaller than a permeability of the band-pass filter for another component of the light, a wave-length of which another component is not less than 450 nm.

2. A liquid crystal display according to claim 1, further comprising a light guide for guiding the light from the light source to the liquid crystal, wherein the band-pass filter is arranged between the light source and the light guide.

3. A liquid crystal display according to claim 1, further comprising a light guide for guiding the light from the light source, and a diffusing plate for distributing constantly the light over the liquid crystal, wherein the diffusing plate is arranged between the light guide and the liquid crystal, and the band-pass filter is arranged between the diffusing plate and the light guide.

4. A liquid crystal display according to claim 1, wherein the band-pass filter is arranged on the light source.

5. A liquid crystal display according to claim 1, further comprising a light guide for guiding the light from the light source to the liquid crystal, wherein the band-pass filter is arranged on the light guide.

6. A liquid crystal display according to claim 1, further comprising a pair of a first substrate being transparent and a second substrate being at least partially transparent, wherein the liquid crystal is arranged between the first and second substrates, the band-pass filter is arranged on at least one of the first and second substrates.

7. A liquid crystal display according to claim 1, further comprising a color filter including a portion for transmitting therethrough a blue light, wherein the portion includes an agent for absorbing the component of the light as the band-pass filter.

8. A liquid crystal display according to claim 1, wherein the band-pass filter is arranged on at least one of the first and second polarizer plates.

9. A liquid crystal display according to claim 1, wherein the band-pass filter is a stack of layers.

10. A liquid crystal display according to claim 1, wherein the band-pass filter is a polymer for absorbing the component of the light.

11. A liquid crystal display according to claim 1, wherein the band-pass filter is a resin including an agent for absorbing the component of the light.

12. A liquid crystal display according to claim 1, wherein the light source includes a fluorescent substance for generating the light.

13. A liquid crystal display according to claim 1, wherein the liquid crystal and the pair of first and second polarizer plates forms a normally close type liquid crystal display unit.

14. A liquid crystal display according to claims 1, wherein a direction in which the light is transmitted in the liquid crystal is transverse with respect to a direction in which the electric field is generated.

15. A liquid crystal display according to claim 1, wherein the liquid crystal and the pair of first and second polarizer plates forms a super twisted nematic type liquid crystal display unit.

16. A liquid crystal display according to claim 1, wherein the band-pass filter is arranged between the light source and the liquid crystal.

17. A liquid crystal display for displaying an image to be visible for a viewer, comprising:

a liquid crystal;

a pair of electrodes for controlling an orientation of at least a part of the liquid crystal in accordance with an electric field between the electrodes;

a light source for generating a light to be transmitted through the liquid crystal to the viewer;

a pair of first and second polarizer plates, the first polarizer plate being arranged between the liquid crystal and the light source, and the second polarizer plate being arranged between the liquid crystal and the viewer; and

a band-pass filter for absorbing a component of the light, a wave-length of which component is not more than 440 nm, and the band-pass filter being arranged between the light source and the viewer;

wherein a permeability of the band-pass filter for the component of wave-length 400-440 nm is smaller than a permeability of the band-pass filter for another component of the light, a wave-length of which another component is not less than 450 nm.

18. A liquid crystal display for displaying an image to be visible for a viewer, comprising:

a liquid crystal;

a pair of electrodes for controlling an orientation of at least a part of the liquid crystal in accordance with an electric field between the electrodes;

a light source for generating a light to be transmitted through the liquid crystal to the viewer;

a pair of first and second polarizer plates, the first polarizer plate being arranged between the liquid crystal and the light source, and the second polarizer plate being arranged between the liquid crystal and the viewer; and

a band-pass filter for absorbing a component of the light, a wave-length of which component is not more than 440 nm, and the band-pass filter being arranged between the light source and the viewer;

wherein a permeability of the band-pass filter decreases in accordance with a decrease of a wave-length of a light to be transmitted through the band-pass filter when the wave-length of the light to be transmitted through the band-pass filter is less than 450 nm.

19. A liquid crystal display for displaying an image to be visible for a viewer, comprising:

a liquid crystal;

a pair of electrodes for controlling an orientation of at least a part of the liquid crystal in accordance with an electric field between the electrodes;

a light source for generating a light to be transmitted through the liquid crystal to the viewer;

a pair of first and second polarizer plates, the first polarizer plate being arranged between the liquid crystal and the light source, and the second polarizer plate being arranged between the liquid crystal and the viewer; and

a band-pass filter for absorbing a component of the light, a wave-length of which component is not more than 440 nm, and the band-pass filter being arranged between the light source and the viewer;

wherein a permeability of the band-pass filter decreases in accordance with a decrease of a wave-length of a light to be transmitted through the band-pass filter when the wave-length of the light to be transmitted through the band-pass filter is 400-440 nm.