Liquid crystal display

• US 7,489,374 B2
• Filed: 12/23/2004
• Issued: 02/10/2009
• Est. Priority Date: 12/26/2003
• Status: Active Grant

• Current Assignee: Panasonic Intellectual Property Corporation of America (Panasonic Holdings Corporation)
• Original Assignee: Hitachi Displays Limited (Japan Display Incorporated)
• Inventors: Maehara, Mutsumi, Kondo, Katsumi, Utsumi, Yuka, Sugibayashi, Makiko, Hiyama, Ikuo
• Primary Examiner(s): Nelms; David
• Assistant Examiner(s): NGUYEN, THANH NHAN P
• Application Number:
  US11/020,083
• Publication Number:
  US 20050140855A1
• Time in Patent Office: 1,510 Days
• Field of Search: 349104-106, 349/141, 349/65, 349/96
• US Class Current: 349/106
• CPC Class Codes: G02F 1/133514 Colour filters
• CPC Class Codes: G02F 1/133707 Structures for producing distorted electric fields, e.g. bumps, protrusions, recesses, slits in pixel electrodes
• CPC Class Codes: G02F 1/134363 for applying an electric field parallel to the substrate, i.e. in-plane switching [IPS]
• CPC Class Codes: G02F 1/1393 the birefringence of the liquid crystal being electrically controlled, e.g. ECB-, DAP-, HAN-, PI-LC cells G02F1/1396, G02F1/141 take precedence
• CPC Class Codes: G02F 2203/04 wavelength independent

Abstract

A normally-closed liquid crystal display includes a component to selectively absorb characteristic leakage light occurring at black representation. Therefore, when black is displayed, occurrence of unnecessary leakage light due to partial depolarization of polarized light caused by a component of an LCD panel can be suppressed. It is therefore possible to provide a liquid crystal display in which display performance of black is improved to clearly display black.

Claims

1. A liquid crystal display of in-plane-switching type, comprising:

a normally-closed liquid crystal display panel including a pair of substrates including a polarizer and a liquid crystal layer sandwiched between the pair of substrates;

a light source unit arranged with respect to a rear surface of the liquid crystal display panel; and

a spectrum absorbing unit arranged between the normally-closed liquid crystal display panel and the light source unit, including a component for absorbing light spectrum within a predetermined range of wavelength propagated from the light source unit to the liquid crystal display panel, by partial depolarization of polarization of a light emitted by the light source unit;

wherein the absorbing component includes a polyvinyl alcohol macromolecular layer including a pigment having an absorption peak at a wavelength of 490 nm.

2. A liquid crystal display, comprising:

a pair of polarizers arranged opposing to each other;

a pair of substrates arranged opposing to each other, the substrates being in contact with inner sides of the respective polarizers;

a color filter arranged to be in contact with an inner side of one of the pair of substrates;

liquid crystal sandwiched between an inner side of the other one of the pair of substrates and the color filter;

a light emitting component arranged on an outer side of the other one of the pair of substrates for supplying light to the liquid crystal; and

a spectrum absorbing unit including an absorbing component disposed between the other one of the pair of substrates and the light emitting component for absorbing a light spectrum within a predetermined range of wavelength of the light spectrum propagated from the light emitting component to the liquid crystal, the absorbing component including a pigment having dichroism in a wavelength range from 400 nm to 500 nm including a wavelength range greater than 440 nm of light from the light emitting component.

3. A liquid crystal display according to claim 2, wherein absorption and transmission of the absorbing component vary on a plane of polarization.

4. A liquid crystal display according to claim 2, wherein absorbing component comprises a glass plate on which a polymer layer is formed.

5. A liquid crystal display of in-plane-switching type, comprising:

a normally-closed liquid crystal display panel including a pair of substrates including a polarizer and a liquid crystal layer sandwiched between the pair of substrates;

a light source unit arranged with respect to a rear surface of the liquid crystal display panel; and

a spectrum absorbing unit arranged between the normally-closed liquid crystal display panel and the light source unit, including a component for aborbing light spectrum within a predetermined range or wavelength propagated from the light source unit to the liquid crystal display panel, by partial depolarization of polarization of a light emitted by the light source unit;

wherein the predetermined wavelength range is a wavelength range from 400 nm to 500 nm including a wavelength range greater than 440 nm.

6. A liquid crystal display according to claim 5 wherein the component for absorbing the light spectrum is a component for absorbing the light spectrum propagated, when incident light incident from the light source to the liquid crystal display panel passes through the display panel, through scattering of the light by particles including in a constituent component of the display panel, the particles each having a diameter less than a wavelength of visible light.

7. A liquid crystal display according to claim 5, wherein absorption and transmission of the absorbing component vary on a plane of polarization.

8. A liquid crystal display according to claim 5, wherein the absorbing component comprises a glass plate on which a polymer layer is formed.