Liquid crystal display device

• US 20060050216A1
• Filed: 09/07/2005
• Published: 03/09/2006
• Est. Priority Date: 09/07/2004
• Status: Abandoned Application

• Current Assignee: Japan Display Central Incorporated (Japan Display Incorporated)
• Original Assignee: Japan Display Central Incorporated (Japan Display Incorporated)
• Inventors: Joten, Kazuhiro
• Application Number:
  US11/219,761
• Publication Number:
  US 20060050216A1
• Time in Patent Office: Days
• US Class Current: 349/117
• CPC Class Codes: G02F 1/133528 Polarisers
• CPC Class Codes: G02F 1/133531 characterised by the arrangement of polariser or analyser axes
• CPC Class Codes: G02F 1/133541 Circular polarisers
• CPC Class Codes: G02F 1/13363 Birefringent elements, e.g. for optical compensation
• CPC Class Codes: G02F 1/133638 Waveplates, i.e. plates with a retardation value of lambda/n
• CPC Class Codes: G02F 1/1337 Surface-induced orientation of the liquid crystal molecules, e.g. by alignment layers
• CPC Class Codes: G02F 1/133738 for homogeneous alignment
• CPC Class Codes: G02F 2203/66 Normally white display, i.e. the off state being white
• CPC Class Codes: G02F 2413/02 Number of plates being 2
• CPC Class Codes: G02F 2413/08 with a particular optical axis orientation

Abstract

A liquid crystal display device including a plurality of pixels arranged in a matrix includes a liquid crystal display panel in which a liquid crystal layer is held between an array substrate and a counter-substrate that are disposed to face each other, a first polarization control element provided on an outer surface of the array substrate, which is opposed to a surface of the array substrate that holds the liquid crystal layer, and a second polarization control element provided on an outer surface of the counter-substrate, which is opposed to a surface of the counter-substrate that holds the liquid crystal layer. When a vertical direction of a screen is set to be a reference azimuth, the liquid crystal layer includes liquid crystal molecules that are homogeneously aligned in an azimuth different from the reference azimuth.

Claims

1. A liquid crystal display device including a plurality of pixels arranged in a matrix, the device comprising:

a transmissive liquid crystal display panel in which a liquid crystal layer is held between a first substrate and a second substrate that are disposed to face each other;

a first polarization control element provided on an outer surface of the first substrate, which is opposed to a surface of the first substrate that holds the liquid crystal layer, the first polarization control element being configured to pass light in a polarization state of elliptically polarized light; and

a second polarization control element provided on an outer surface of the second substrate, which is opposed to a surface of the second substrate that holds the liquid crystal layer, the second polarization control element being configured to pass light in a polarization state of elliptically polarized light, whose direction of rotation is opposite to a direction of rotation of the elliptically polarized light that is passed through the first polarization control element,

wherein when a vertical direction of a screen is set to be a reference azimuth, the liquid crystal layer includes liquid crystal molecules that are homogeneously aligned in an azimuth that is different from the reference azimuth.

2. The liquid crystal display device according to claim 1, wherein when a clockwise direction relative to the reference azimuth in the screen is indicated with a negative sign and a counterclockwise direction relative to the reference azimuth in the screen is indicated with a positive sign, a director of the liquid crystal molecules is set in a range of −

45°

±

25°

or in a range of +45°

±

10°

, relative to the reference azimuth.

3. The liquid crystal display device according to claim 1, wherein when a clockwise direction relative to the reference azimuth in the screen is indicated with a negative sign and a counterclockwise direction relative to the reference azimuth in the screen is indicated with a positive sign, a director of the liquid crystal molecules is set in a range of +30°

±

15°

, relative to the reference azimuth.

4. The liquid crystal display device according to claim 1, wherein at least one of the first polarization control element and the second polarization control element comprises one polarizer plate and one phase plate.

5. The liquid crystal display device according to claim 4, wherein the phase plate is a ¼

wavelength plate that provides a phase difference of ¼

wavelength between an ordinary ray and an extraordinary ray with respect to light of a predetermined wavelength.

6. The liquid crystal display device according to claim 4, wherein at least one of the first polarization control element and the second polarization control element, an acute angle formed between an absorption axis of the polarizer plate and a slow axis of the phase plate is set in a range of 25°

to 70°

.

7. The liquid crystal display device according to claim 4, wherein at least one of the first polarization control element and the second polarization control element, an acute angle formed between an absorption axis of the polarizer plate and a slow axis of the phase plate is set in a range between 25°

or more and less than 40°

, or in a range between more than 45° and

65°

or less.

8. The liquid crystal display device according to claim 7, wherein an ellipticity of light with a wavelength of 550 nm, which passes through at least one of the first polarization control element and the second polarization control element, is between 0.5 and 0.85.

9. The liquid crystal display device according to claim 7, wherein a difference between a maximum value and a minimum value of ellipticity of light in a range of wavelengths of 450 nm to 650 nm, which passes through at least one of the first polarization control element and the second polarization control element, is less than 0.15.

10. The liquid crystal display device according to claim 1, further comprising a backlight unit that illuminates the liquid crystal display panel from the first polarization control element side.

11. The liquid crystal display device according to claim 1, wherein a display mode is a normally white mode.