LIQUID CRYSTAL DISPLAY DEVICE

• US 20090303419A1
• Filed: 05/18/2009
• Published: 12/10/2009
• Est. Priority Date: 06/05/2008
• Status: Abandoned Application

• Current Assignee: Epson Imaging Devices Corporation (Seiko Group)
• Original Assignee: Epson Imaging Devices Corporation (Seiko Group)
• Inventors: KOMA, Norio
• Application Number:
  US12/467,569
• Publication Number:
  US 20090303419A1
• Time in Patent Office: Days
• US Class Current: 349/74
• CPC Class Codes: G02F 1/133528 Polarisers
• CPC Class Codes: G02F 1/133601 for spatial active dimming
• CPC Class Codes: G02F 1/13363 Birefringent elements, e.g. for optical compensation
• 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 1/1347 Arrangement of liquid crystal layers or cells in which the final condition of one light beam is achieved by the addition of the effects of two or more layers or cells

Abstract

Provided is a liquid crystal display device including: a first liquid crystal panel including a first liquid crystal layer; a second liquid crystal panel arranged to overlap the first liquid crystal panel and including a second liquid crystal layer; and color filters provided on the first liquid crystal panel, wherein color filters are not provided on the second liquid crystal panel, the first liquid crystal panel includes a plurality of first pixels, the second liquid crystal panel includes a plurality of second pixels, each of the first pixels of the first liquid crystal panel includes a plurality of sub pixels, and the second pixels are provided such that one second pixel corresponds to the plurality of sub pixels.

Claims

1. A liquid crystal display device comprising:

a first liquid crystal panel including a first liquid crystal layer;

a second liquid crystal panel arranged to overlap the first liquid crystal panel and including a second liquid crystal layer; and

color filters provided on the first liquid crystal panel,

wherein color filters are not provided on the second liquid crystal panel,

the first liquid crystal panel includes a plurality of first pixels,

the second liquid crystal panel includes a plurality of second pixels,

each of the first pixels of the first liquid crystal panel includes a plurality of sub pixels, and

the second pixels are provided such that one second pixel corresponds to the plurality of sub pixels.

2. The liquid crystal display device according to claim 1, wherein one second pixel is arranged in correspondence with each first pixel including the plurality of sub pixels.

3. The liquid crystal display device according to claim 2, wherein, among signal voltages applied to the plurality of sub pixels configuring each of the first pixels of the first liquid crystal panel, a signal voltage having maximum transmissivity is applied to the second pixel of the second liquid crystal panel corresponding to each of the first pixels of the first liquid crystal panel.

4. The liquid crystal display device according to claim 3, wherein, if the transmissivity of the sub pixel having maximum transmissivity of the plurality of sub pixels configuring each of the first pixels is more than a predetermined threshold value, a signal voltage having maximum transmissivity is applied to the second pixel corresponding to each of the first pixels, and

if the transmissivity of the sub pixel having maximum transmissivity of the plurality of sub pixels configuring each of the first pixels is equal to or less than the predetermined threshold value, a signal voltage having transmissivity corresponding to a sub pixel having maximum transmissivity of the sub pixels configuring each of the first pixels is applied to the second pixel corresponding to each of the first pixels.

5. The liquid crystal display device according to claim 1, further comprising:

a first polarization plate interposed between the first liquid crystal layer and the second liquid crystal layer;

a second polarization plate provided on the surface of the first liquid crystal layer at side opposite to the first polarization plate side; and

a third polarization plate provided on the surface of the second liquid crystal layer at side opposite to the first polarization plate side,

wherein a polarization degree of at least one of the first polarization plate, the second polarization plate and the third polarization plate is 99% or less.

6. The liquid crystal display device according to claim 5, wherein a first retardation film is disposed in at least one of spaces between the first liquid crystal layer and the second polarization plate and between the second liquid crystal layer and the third polarization plate.

7. The liquid crystal display device according to claim 5, further comprising:

a first substrate interposed between the first liquid crystal layer and the first polarization plate; and

a second substrate interposed between the second liquid crystal layer and the first polarization plate,

wherein the first substrate and the second substrate protrude from the first liquid crystal layer and the second liquid crystal layer in plan view, and

the first polarization plate is formed on the substantially whole surfaces of the first substrate and the second substrate.

8. The liquid crystal display device according to claim 5, wherein the first polarization plate includes a pair of polarization plates and a second retardation film interposed between the pair of polarization plates.

9. The liquid crystal display device according to claim 8, wherein the second retardation film is a ½

wavelength plate.

10. The liquid crystal display device according to claim 9, wherein the polarization axes of the pair of polarization plates form an angle of 45°

with each other, and the second retardation film rotates the polarization of light incident from one of the pair of polarization plates by 45° and

emits the light to the other polarization plate.

11. The liquid crystal display device according to claim 1, further comprising:

a first polarization plate provided between the first liquid crystal layer and the second liquid crystal layer;

a first substrate provided between the first liquid crystal layer and the first polarization plate; and

a second substrate provided between the second liquid crystal layer and the first polarization plate,

wherein a first pixel electrode and a common electrode are provided on the surface of the first substrate at the first liquid crystal layer side, and

a second pixel electrode and a second common electrode are provided on the surface of the second substrate at the second liquid crystal layer side.

12. The liquid crystal display device according to claim 1, further comprising:

a first polarization plate provided between the first liquid crystal layer and the second liquid crystal layer;

a first substrate provided between the first liquid crystal layer and the first polarization plate;

a first counter substrate disposed to face the first substrate;

a second substrate provided between the second liquid crystal layer and the first polarization plate; and

a second counter substrate disposed to face the second substrate,

wherein a first pixel electrode is provided on the surface of the first substrate at the first liquid crystal layer side, and a first common electrode is provided on the surface of the first counter substrate to face the first pixel electrode with the first liquid crystal layer interposed therebetween, and

a second pixel electrode and a second common electrode are provided on the surface of the second substrate at the second liquid crystal layer side.

13. The liquid crystal display device according to claim 1, wherein a distance d between the first liquid crystal layer and the second liquid crystal layer is configured to satisfy a relationship of d≦

p/0.33 when a pixel pitch of the second pixels is p.

14. The liquid crystal display device according to claim 13, wherein the distance d between the first liquid crystal layer and the second liquid crystal layer is configured to satisfy a relationship of d≦

p/0.44.

15. A liquid crystal display device comprising:

a first liquid crystal panel including a first liquid crystal layer;

a second liquid crystal panel arranged to overlap the first liquid crystal panel and including a second liquid crystal layer; and

color filters provided on the first liquid crystal panel,

wherein color filters are not provided on the second liquid crystal panel,

the first liquid crystal panel includes a plurality of first pixels,

the second liquid crystal panel includes a plurality of second pixels,

the second pixels are provided in correspondence with the first pixels, and

a distance d between the first liquid crystal layer and the second liquid crystal layer is configured to satisfy a relationship of d≦

p/0.33 when a pixel pitch of the second pixels is p.

16. The liquid crystal display device according to claim 15, wherein the distance d between the first liquid crystal layer and the second liquid crystal layer is configured to satisfy a relationship of d≦

p/0.44.