Display device and electronic equipment having the same

• US 20040125430A1
• Filed: 07/03/2003
• Published: 07/01/2004
• Est. Priority Date: 07/04/2002
• Status: Active Grant

• Current Assignee: BOE Technology Group Co., Ltd.
• Original Assignee: Seiko Epson Corporation (Seiko Group)
• Inventors: Kasajima, Yasushi, Eisaki, Saori, Tsuchihashi, Toshihiko, Ushiki, Takeyoshi, Maeda, Tsuyoshi, Wada, Hiroshi
• Granted Patent: US 7,268,841 B2
• Time in Patent Office: Days
• US Class Current: 359/247
• CPC Class Codes: G02F 1/133536 Reflective polarizers G02F1/13362 takes precedence
• 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

A display device 100 has a display unit 110 and a display switching unit 120. The display switching unit 120 is provided with a reflective polarizing plate 121, a liquid crystal panel 122, and a polarizing plate 123 arranged in this order from the side of the display unit 110 to the observation side. By controlling the liquid crystal panel 122, the display switching unit can be switched between a light transmissive state and a light reflective state. The display unit 110 and the display switching unit 120 are optically adhered to each other by an adhesive layer 131. Thus, deterioration of the contrast by boundary reflection can be restrained, and the flatness and the rigidity of the device can be improved.

Claims

1. A display device comprising:

a display unit for forming a predetermined display mode; and

a display switching unit overlapping the display unit at least in one portion,

wherein the display switching unit includes first polarization component selecting means, polarized-light transmitting axis changing means, and second polarization component selecting means sequentially disposed from the display unit toward an observation side,

the first polarization component selecting means transmits a first polarization component and reflects a second polarization component having a polarization axis intersecting with a polarization axis of the first polarization component,

the polarized-light transmitting axis changing means is switchable between a state of transmitting light after changing the first polarization component into the second polarization component and a state of transmitting light without substantially changing the polarization axis of the incident light,

the second polarization component selecting means transmits one of the first polarization component and the second polarization component and absorbs or reflects the other polarization component,

the display unit emits the first polarization component for forming the display mode, and

the display unit and the display switching unit are optically adhered to each other.

2. The display device according to claim 1, wherein

the display unit and the display switching unit are optically adhered to each other by adhesive.

3. The display device according to claim 2, wherein

refraction index of the adhesive layer is within a range of 1.30 to 1.50.

4. The display device according to claim 2, wherein the adhesive layer is a gel material.

14. The display device according to claim 1, wherein

the second polarization component selecting means is absorptive polarization selecting means for transmitting the one of the polarization components and absorbing the other polarization component.

34. An electronic apparatus comprising:

the display device according to claim 1;

a display driving means for controlling the display unit; and

a switch driving means for controlling the display switching means.

5. A display device comprising:

a display unit for forming a predetermined display mode; and

a display switching unit overlapping with the display unit at least in one portion,

wherein the display switching unit includes first polarization component selecting means, polarized-light transmitting axis changing means, and second polarization component selecting means sequentially disposed from the display unit toward an observation side,

the first polarization component selecting means transmits a first polarization component and reflects a second polarization component having a polarization axis intersecting with a polarization axis of the first polarization component,

the polarized-light transmitting axis changing means is switchable between a state of transmitting light after changing the first polarization component into the second polarization component and a state of transmitting light without substantially changing the polarization axis of the incident light,

the second polarization component selecting means transmits one of the first polarization component and the second polarization component and absorbs or reflects the other polarization component,

the display unit emits the first polarization component for forming the display mode, and

an anti-reflection coating is formed on both sides of the display switching unit.

6. The display device according to claim 5, wherein

the anti-reflection coating is formed on a surface of the display unit on a side of the display switching unit.

7. A display device comprising:

a display unit for forming a predetermined display mode; and

a display switching unit overlapping with the display unit at least in one portion,

wherein the display switching unit includes first polarization component selecting means, polarized-light transmitting axis changing means, and second polarization component selecting means sequentially disposed from the display unit toward an observation side,

the first polarization component selecting means transmits a first polarization component and reflects a second polarization component having a polarization axis intersecting with a polarization axis of the first polarization component,

the polarized-light transmitting axis changing means is switchable between a state of transmitting light after changing the first polarization component into the second polarization component and a state of transmitting light without substantially changing the polarization axis of the incident light,

the second polarization component selecting means transmits one of the first polarization component and the second polarization component and absorbs or reflects the other polarization component,

the display unit emits the first polarization component for forming the display mode, and

the display switching unit is provided with a whole pixel region, which includes a single pixel arranged on an entire face, and a pixel-arranged region, which includes a plurality of pixels, each pixel having a predetermined shape smaller than the whole pixel region.

8. A display device comprising:

a display unit for forming a predetermined display mode; and

a display switching unit overlapping with the display unit at least in one portion,

wherein the display switching unit includes first polarization component selecting means, polarized-light transmitting axis changing means, and second polarization component selecting means sequentially disposed from the display unit toward an observation side,

the first polarization component selecting means transmits a first polarization component and reflects a second polarization component having a polarization axis intersecting with a polarization axis of the first polarization component,

the polarized-light transmitting axis changing means is switchable between a state of transmitting light after changing the first polarization component into the second polarization component and a state of transmitting light without substantially changing the polarization axis of the incident light,

the second polarization component selecting means transmits one of the first polarization component and the second polarization component and absorbs or reflects the other,

the display unit emits the first polarization component for forming the display mode, and

the display switching unit is provided with a region including the first polarization component selecting means and a region including a third polarization component selecting means for transmitting the first polarization component and for absorbing the second polarization component.

9. A display device comprising:

a display unit for forming a predetermined display mode; and

a display switching unit overlapping with the display unit at least in one portion,

wherein the display switching unit includes first polarization component selecting means, polarized-light transmitting axis changing means, and second polarization component selecting means sequentially disposed from the display unit toward an observation side,

the first polarization component selecting means transmits a first polarization component and reflects a second polarization component having a polarization axis intersecting with a polarization axis of the first polarization component,

the polarized-light transmitting axis changing means is switchable between a state of transmitting light after changing the first polarization component into the second polarization component and a state of transmitting light without substantially changing the polarization axis of the incident light,

the second polarization component selecting means transmits one of the first polarization component and the second polarization component and absorbs or reflects the other polarization component,

the display unit emits the first polarization component for forming the display mode, and

the display unit is provided with a region not overlapping with the display switching unit.

10. A display device comprising:

a display unit for forming a predetermined display mode; and

a display switching unit overlapping with the display unit at least in one portion,

wherein the display switching unit includes first polarization component selecting means, polarized-light transmitting axis changing means, and second polarization component selecting means sequentially disposed from the display unit toward an observation side,

the first polarization component selecting means transmits a first polarization component and reflects a second polarization component having a polarization axis intersecting with a polarization axis of the first polarization component,

the polarized-light transmitting axis changing means is switchable between a state of transmitting light after changing the first polarization component into the second polarization component and a state of transmitting light without substantially changing the polarization axis of the incident light,

the second polarization component selecting means transmits one of the first polarization component and the second polarization component and absorbs or reflects the other,

the display unit emits the first polarization component for forming the display mode, and

the display switching unit is provided with a region not overlapping with the display unit two dimensionally, where a plurality of pixels of a predetermined shape are arranged.

11. A display device comprising:

a display unit for forming a predetermined display mode; and

a display switching unit overlapping with the display unit at least in one portion,

wherein the display switching unit includes first polarization component selecting means, polarized-light transmitting axis changing means, and second polarization component selecting means sequentially disposed from the display unit toward an observation side,

the first polarization component selecting means transmitting a first polarization component and reflects a second polarization component having a polarization axis intersecting with a polarization axis of the first polarization component,

the polarized-light transmitting axis changing means is switchable between a state of transmitting light after changing the first polarization component into the second polarization component and a state of transmitting light without substantially changing the polarization axis of the incident light,

the second polarization component selecting means transmits one of the first polarization component and the second polarization component and absorbs or reflects the other,

the display unit emits the third polarization component for forming the display mode, and

a polarization converting means for converting the third polarization component into the first polarization component is provided between the display unit and the display switching unit.

12. The display device according to claim 11, wherein the polarization converting means is a retardation plate.

13. The display device according to claim 12, wherein the retardation plate is a plate of a half (½

) wavelength.

15. A display device comprising:

a display unit for forming a predetermined display mode; and

a display switching unit overlapping with the display unit at least in one portion,

wherein the display switching unit includes first polarization component selecting means, polarized-light transmitting axis changing means, and second polarization component selecting means sequentially disposed from the display unit toward an observation side,

the first polarization component selecting means transmits a first polarization component and reflects a second polarization component having a polarization axis intersecting with a polarization axis of the first polarization component,

the polarized-light transmitting axis changing means is switchable between a state of transmitting light after changing the first polarization component into the second polarization component and a state of transmitting light without substantially changing the polarization axis of the incident light,

the second polarization component selecting means transmits one of the first polarization component and the second polarization component and absorbs or reflects the other polarization component,

the display unit emits the first polarization component for forming the display mode,

the display unit includes an illuminating device disposed on the side of the display switching unit, and a reflective display device disposed on the opposite side of the illuminating device and away from the display switching unit,

the illuminating device emits light toward the reflective display device and transmits light incident from the reflective display device,

the polarized-light transmitting axis changing means includes a TN-type liquid crystal layer and a voltage application means for applying a predetermined electric field to the TN-type liquid crystal layer in a thickness direction, and

the TN-type liquid crystal layer has Δ

n·

d within a range of 0.7 μ

m to 1.7 μ

m.

16. The display device according to claim 15, wherein

the TN-type liquid crystal layer has the Δ

n·

d within a range of 0.9 μ

m to 1.3 μ

m.

20. The display device according to claim 15, wherein

the second polarization component selecting means is absorptive polarization selecting means for transmitting the one of the polarization components and absorbing the other polarization component.

21. The display device according to claim 15, wherein

the display unit and the display switching unit are optically adhered to each other.

22. The display device according to claim 21, wherein

the display unit and the display switching unit are optically adhered to each other by adhesive.

23. The display device according to claim 22, wherein

refraction index of the adhesive layer is within a range of 1.30 to 1.50.

24. The display device according to claim 22, wherein

the adhesive layer is a gel material.

25. The display device according to claim 15, wherein

an anti-reflection coating is formed on both sides of the display switching unit.

26. The display device according to claim 25, wherein

the anti-reflection coating is formed on a surface of the display unit on the side of the display switching unit.

27. The display device according to claim 15, wherein

the display switching unit is provided with a whole pixel region, which includes a single pixel arranged on an entire face, and a pixel-arranged region, which includes a plurality of pixels, each pixel having a predetermined shape smaller than the whole pixel region.

28. The display device according to claim 15, wherein

the display switching unit is provided with a region including the first polarization component selecting means, and a region including a third polarization component selecting means for transmitting the first polarization component and for absorbing the second polarization component instead of the first polarization component selecting means.

29. The display device according to claim 15, wherein

the display unit is provided with a region not overlapping with the display switching unit.

30. The display device according to claim 15, wherein

the display switching unit is provided with a region not overlapping with the display unit two dimensionally, and a plurality of pixels of a predetermined shape are arranged in the region.

17. A display device comprising:

a display unit for forming a predetermined display mode; and

a display switching unit overlapping with the display unit at least in one portion,

wherein the display switching unit includes first polarization component selecting means, polarized-light transmitting axis changing means, and second polarization component selecting means sequentially disposed from the display unit toward an observation side,

the first polarization component selecting means transmits a first polarization component and reflects a second polarization component having a polarization axis intersecting with a polarization axis of the first polarization component,

the polarized-light transmitting axis changing means is formed to be switchable between a state of transmitting light after changing the first polarization component into the second polarization component and a state of transmitting light without substantially changing the polarization axis of the incident light,

the second polarization component selecting means transmits one of the first polarization component and the second polarization component and absorbs or reflects the other polarization component,

the display unit emits the first polarization component for forming the display mode,

the display unit includes an illuminating device disposed on the side of the display switching unit, and a reflective display device disposed on the opposite side of the illuminating device and away from the display switching unit,

the illuminating device emits light toward the reflective display device and transmits light incident from the reflective display device,

the polarized-light transmitting axis changing means includes a TN-type liquid crystal layer and a voltage application means for applying a predetermined electric field to the TN-type liquid crystal layer in a thickness direction, and

the TN-type liquid crystal layer has Δ

n·

d within a range of 0.50 μ

m to 0.65 μ

m.

18. A display device comprising:

a display unit for forming a predetermined display mode; and

a display switching unit overlapping with the display unit at least in one portion,

wherein the display switching unit includes first polarization component selecting means, polarized-light transmitting axis changing means, and second polarization component selecting means sequentially disposed from the display unit toward an observation side,

the first polarization component selecting means transmits a first polarization component and reflects a second polarization component having a polarization axis intersecting with a polarization axis of the first polarization component,

the polarized-light transmitting axis changing means is formed to be switchable between a state of transmitting light after changing the first polarization component into the second polarization component and a state of transmitting light without substantially changing the polarization axis of the incident light,

the second polarization component selecting means transmits one of the first polarization component and the second polarization component and absorbs or reflects the other,

the display unit includes polarized-light transmitting axis changing means for displaying, and emits the first polarization component for forming the display mode,

the display unit includes an illuminating device disposed on the side of the display switching unit, and a reflective display device, having the polarized-light transmitting axis changing means for displaying, disposed on the opposite side of the illuminating device and away from the display switching unit,

the illuminating device emits light toward the reflective display device and transmits light incident from the reflective display device,

a ratio of α

m=Δ

n_m (λ

=450 nm)/Δ

n_m (λ

=590 nm), indicating wavelength distribution of anisotropic refraction index of the polarized-light transmitting axis changing means, when the anisotropic refraction index for a light of wavelength λ

of the polarized-light transmitting axis changing means is defined as the Δ

n_m(λ

), and α

_d=Δ

n_d(λ

=450 nm/Δ

n_d(λ

=590 nm), indicating wavelength distribution of the anisotropic refraction index of the polarized-light transmitting axis changing means for displaying when the anisotropic refraction index for a light of wavelength λ

of the polarized-light transmitting axis changing means for displaying is defined as Δ

n_d(λ

), is within the range of 0.9 to 1.1.

19. A display device comprising:

a display unit for forming a predetermined display mode; and

a display switching unit overlapping with the display unit at least in one portion,

wherein the display switching unit includes first polarization component selecting means, polarized-light transmitting axis changing means, and second polarization component selecting means sequentially disposed from the display unit toward an observation side,

the first polarization component selecting means transmits a first polarization component and reflects a second polarization component having a polarization axis intersecting with a polarization axis of the first polarization component,

the polarized-light transmitting axis changing means is switchable between a state of transmitting light after changing the first polarization component into the second polarization component and a state of transmitting light without substantially changing the polarization axis of the incident light,

the second polarization component selecting means transmits one of the first polarization component and the second polarization component and absorbs or reflects the other,

the display unit emits the first polarization component for forming the display mode,

the display unit includes an illuminating device disposed on the side of the display switching unit, and a reflective display device disposed on the opposite side of the illuminating device and away from the display switching unit,

the illuminating device emits light toward the reflective display device and transmits light incident from the reflective display device, and

a variation amount of the anisotropic refraction index Δ

n_m in a visible light region of the polarized-light transmitting axis changing means is within ±

8% in the range of −

20°

C. to 60°

C. with respect to a temperature of 25°

C.

31. A display device comprising:

a display unit for forming a predetermined display mode; and

a display switching unit overlapping with the display unit at least in one portion,

wherein the display switching unit includes first polarization component selecting means, polarized-light transmitting axis changing means, and second polarization component selecting means sequentially disposed from the display unit toward an observation side,

the first polarization component selecting means transmits a first polarization component and reflects a second polarization component having a polarization axis intersecting with a polarization axis of the first polarization component,

the polarized-light transmitting axis changing means is switchable between a state of transmitting the light after changing the first polarization component into the second polarization component and a state of transmitting the light without substantially changing the polarization axis of the incident light,

the second polarization component selecting means transmits one of the first polarization component and the second polarization component and absorbs or reflects the other polarization component,

the display unit emits the third polarization component for forming the display mode,

the display unit includes an illuminating device disposed on the side of the display switching unit, and a reflective display device disposed on the opposite side of the illuminating device and away from the display switching unit,

the illuminating device emits light toward the reflective display device and transmits light incident from the reflective display device, and

a polarization converting means for converting the third polarization component into the first polarization component is provided between the display unit and the display switching unit.

32. The display device according to claim 31, wherein

the polarization converting means is a retardation plate.

33. The display device according to claim 32, wherein the retardation plate is a plate of a half (½

) wavelength.