DISPLAY DEVICE

• US 20070200978A1
• Filed: 02/21/2007
• Published: 08/30/2007
• Est. Priority Date: 02/24/2006
• Status: Active Grant

• Current Assignee: Semiconductor Energy Laboratory Co., Ltd.
• Original Assignee: Semiconductor Energy Laboratory Co., Ltd.
• Inventors: NISHI, Takeshi, ISHITANI, Tetsuji, EGI, Yuji
• Granted Patent: US 7,956,957 B2
• Time in Patent Office: Days
• US Class Current: 349/96
• 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 2203/64 Normally black display, i.e. the off state being black

Abstract

An object is to provide a display device with high contrast ratio. Another object is to manufacture such a high-performance display device at low cost. In a display device having a display element interposed between a pair of light-transmitting substrates, a stack of polarizer-including layers in a parallel nicol state is provided outside each of the light-transmitting substrates. Here, transmission axes of polarizers that are stacked in the stack on one side of the display element and transmission axes of polarizers that are stacked in the stack on another side of the display element are arranged to be displaced from a cross nicol state. Also, a retardation film may be provided between the polarizers that are stacked and the substrate.

Claims

1. A display device comprising:

a first light-transmitting substrate and a second light-transmitting substrate arranged to face each other;

a display element disposed between the first light-transmitting substrate and the second light-transmitting substrate;

a first layer including first stacked polarizers adjacent to the first light-transmitting substrate; and

a second layer including second stacked polarizers adjacent to the second light-transmitting substrate,

wherein the first light-transmitting substrate and the second light-transmitting substrate are disposed between the first layer and the second layer,

wherein transmission axes of the first stacked polarizers are arranged in a parallel nicol state,

wherein transmission axes of the second stacked polarizers are arranged in a parallel nicol state, and

wherein the transmission axes of the first stacked polarizers and the transmission axes of the second stacked polarizers are arranged in a cross nicol state with a deviation.

2. The display device according to claim 1, further comprising at least a pair of protective layers,

wherein the first layer is disposed between the pair of protective layers.

3. The display device according to claim 1, further comprising a protective layer,

wherein the first layer comprises at least a first polarizer and a second polarizer, and

wherein the protective layer is disposed between the first polarizer and the second polarizer.

4. The display device according to claim 1,

wherein the first layer comprises a first polarizer and a second polarizer, and

wherein the first polarizer is in contact with the second polarizer.

5. The display device according to claim 1, further comprising a light source,

wherein the second layer is disposed between the display element and the light source.

6. The display device according to claim 1, wherein the transmission axes of the first stacked polarizers and the transmission axes of the second stacked polarizers are arranged in cross nicol state with the deviation in the range of −

3 degrees to +3 degrees.

7. The display device according to claim 1, wherein the display element is a liquid crystal element.

8. A display device comprising:

a first light-transmitting substrate and a second light-transmitting substrate arranged to face each other;

a display element disposed between the first light-transmitting substrate and the second light-transmitting substrate;

a first layer including first stacked polarizers adjacent to the first light-transmitting substrate;

a second layer including second stacked polarizers adjacent to the second light-transmitting substrate;

a first retardation film disposed between the first light-transmitting substrate and the first layer; and

a second retardation film disposed between the second light-transmitting substrate and the second layer,

wherein the first light-transmitting substrate and the second light-transmitting substrate are disposed between the first layer and the second layer,

wherein transmission axes of the first stacked polarizers are arranged in a parallel nicol state,

wherein transmission axes of the second stacked polarizers are arranged in a parallel nicol state, and

wherein the transmission axes of the first polarizers and the transmission axes of the second polarizers are arranged in a cross nicol state with a deviation.

9. The display device according to claim 8, further comprising at least a pair of protective layers,

wherein the first layer is disposed between the pair of protective layers.

10. The display device according to claim 8, further comprising a protective layer,

wherein the first layer comprises at least a first polarizer and a second polarizer, and

wherein the protective layer is disposed between the first polarizer and the second polarizer.

11. The display device according to claim 8,

wherein the first layer comprises a first polarizer and a second polarizer, and

wherein the first polarizer is in contact with the second polarizer.

12. The display device according to claim 8, further comprising a light source,

wherein the second layer is disposed between the display element and the light source.

13. The display device according to claim 8, wherein the transmission axes of the first stacked polarizers and the transmission axes of the second stacked polarizers are arranged in cross nicol state with the deviation in the range of -3 degrees to +3 degrees.

14. The display device according to claim 8, wherein the display element is a liquid crystal element.

15. A display device comprising:

a first light-transmitting substrate and a second light-transmitting substrate arranged to face each other;

a display element disposed between the first light-transmitting substrate and the second light-transmitting substrate;

a first layer including first stacked polarizers adjacent to the first light-transmitting substrate; and

a second layer including second stacked polarizers adjacent to the second light-transmitting substrate,

wherein the first light-transmitting substrate and the second light-transmitting substrate are disposed between the first layer and the second layer,

wherein the first layer comprises a first polarizer, a second polarizer, and third polarizer,

wherein a transmission axis of the first polarizer, a transmission axis of the second polarizer and a transmission axis of the third polarizer are arranged in a parallel nicol state,

wherein transmission axes of the second stacked polarizers are arranged in a parallel nicol state, and

wherein the transmission axes of the first stacked polarizers and the transmission axes of the second stacked polarizers are arranged in a cross nicol state with a deviation.

16. The display device according to claim 15, further comprising at least a pair of protective layers,

wherein the first layer is disposed between the pair of protective layers.

17. The display device according to claim 15, further comprising a protective layer,

wherein the protective layer is disposed between the first polarizer and the second polarizer.

18. The display device according to claim 15,

wherein the first polarizer is in contact with the second polarizer.

19. The display device according to claim 15, further comprising a light source,

wherein the second layer is disposed between the display element and the light source.

20. The display device according to claim 15, wherein the transmission axes of the first stacked polarizers and the transmission axes of the second stacked polarizers are arranged in cross nicol state with the deviation in the range of -3 degrees to +3 degrees.

21. The display device according to claim 15, wherein the display element is a liquid crystal element.

22. A display device comprising:

a first light-transmitting substrate and a second light-transmitting substrate arranged to face each other;

a display element disposed between the first light-transmitting substrate and the second light-transmitting substrate;

a first layer including first stacked polarizers adjacent to the first light-transmitting substrate;

a second layer including second stacked polarizers adjacent to the second light-transmitting substrate;

a first retardation film disposed between the first light-transmitting substrate and the first layer; and

a second retardation film disposed between the second light-transmitting substrate and the second layer,

wherein the first light-transmitting substrate and the second light-transmitting substrate are disposed between the first layer and the second layer,

wherein the first layer comprises a first polarizer, a second polarizer, and third polarizer,

wherein a transmission axis of the first polarizer, a transmission axis of the second polarizer and a transmission axis of the third polarizer are arranged in a parallel nicol state,

wherein transmission axes of the second stacked polarizers are arranged in a parallel nicol state, and

wherein the transmission axes of the first stacked polarizers and the transmission axes of the second stacked polarizers are arranged in a cross nicol state with a deviation.

23. The display device according to claim 22, further comprising at least a pair of protective layers,

wherein the first layer is disposed between the pair of protective layers.

24. The display device according to claim 22, further comprising a protective layer,

wherein the protective layer is disposed between the first polarizer and the second polarizer.

25. The display device according to claim 22,

wherein the first polarizer is in contact with the second polarizer.

26. The display device according to claim 22, further comprising a light source,

wherein the second layer is disposed between the display element and the light source.

27. The display device according to claim 22, wherein the transmission axes of the first stacked polarizers and the transmission axes of the second stacked polarizers are arranged in cross nicol state with the deviation in the range of -3 degrees t 0 +3 degrees.

28. The display device according to claim 22, wherein the display element is a liquid crystal element.