Display devices, electronic apparatus using the same, and polarized light separator

• US 6,141,068 A
• Filed: 02/11/1999
• Issued: 10/31/2000
• Est. Priority Date: 06/13/1997
• Status: Expired due to Term

• Current Assignee: BOE Technology Group Co., Ltd.
• Original Assignee: Seiko Epson Corporation (Seiko Group)
• Inventors: Iijima, Chiyoaki
• Primary Examiner(s): Sikes, William L.
• Assistant Examiner(s): CHOWDHURY, TARIFUR RASHID
• Application Number:
  US09/242,346
• Time in Patent Office: 628 Days
• Field of Search: 349/96, 349/98, 349/117, 349/113
• US Class Current: 349/96
• CPC Class Codes: G02F 1/133504 Diffusing, scattering, diffracting elements associated to illuminating devices G02F1/133606
• CPC Class Codes: G02F 1/133536 Reflective polarizers G02F1/13362 takes precedence
• CPC Class Codes: G02F 1/133545 Dielectric stack polarisers
• CPC Class Codes: G02F 1/133553 Reflecting elements associated to illuminating devices G02F1/133605
• CPC Class Codes: G02F 1/133621 providing coloured light G02F1/133617, G02F1/133533 take precedence
• CPC Class Codes: G02F 1/1397 the twist being substantially higher than 90°, e.g. STN-, SBE-, OMI-LC cells

Abstract

A light-scattering layer 1150, a polarized light separator 1160, and a polarized light separator 1180 are provided in this order below a TN liquid crystal 1140. The polarized light separators 1160 and 1180 are polarized light separators for reflecting light of a linearly polarized light of a wavelength region (Δλ) in the X direction, and transmitting light of an other wavelength region (-Δλ). Since the wavelength region (Δλ) of the polarized light separator 1160 and 1180 are different from each other, as viewed from the light incident side, in a voltage non-application section 1120, light that is reflected by the polarized light separator 1160 becomes emitted light 1122 of a color of the wavelength region (Δλ1), and in a voltage application section 1110, light that is transmitted through the polarized light separator 1160 is reflected by the polarized light separator 1180 to become emitted light 1112 of a color of the wavelength region (Δλ2). Therefore, as viewed from the light incident side, two-color display of the color of the wavelength region (Δλ2) can be obtained on a color background of the wavelength region (Δλ1).

Claims

1. A display device, comprising:

a variable transmission polarization axis means capable of varying a transmission polarization axis;

a first polarized light separating means which is arranged on one side of said variable transmission polarization axis means, which transmits light of a linearly polarized light component in a first direction, and which reflects or absorbs light of a linearly polarized light component in a direction different from said first direction;

a second polarized light separating means which is arranged on another side of said variable transmission polarization axis means, which transmits light of a linearly polarized light component in a second direction, and which reflects, of light of a linearly polarized light component in a predetermined direction different from said second direction, a component of a first wavelength region Δ

λ

1 and transmits a component of a wavelength region -Δ

λ

1 different from said first wavelength component; and

a third polarized light separating means which is placed on a side opposite to said variable transmission polarization axis means with respect to said second polarized light separating means, which transmits light of a linearly polarized light component in a third direction, and which reflects, of light of a linearly polarized light component in a predetermined direction different from said third direction, a component of a second wavelength region Δ

λ

2 and transmits a component of a wavelength region -Δ

λ

2 different from said second wavelength component.

2. The display device as claimed in claim 1, wherein said variable transmission polarization axis means further comprises a liquid crystal device.

3. The display device as claimed in claim 2, wherein said liquid crystal further comprises a TN liquid crystal, an STN liquid crystal, or an ECB liquid crystal.

4. The display device as claimed in claim 1, wherein said first polarized light separating means further comprises a polarizer which transmits light of a linearly polarized light component in said first direction and which absorbs light of a linearly polarized light component in a direction perpendicular to said first direction.

5. The display device as claimed in claim 1, wherein said second polarized light separating means further comprises a reflective polarizer which transmits light of a linearly polarized light component in said second direction and which reflects light of a component of said first wavelength region Δ

λ

1 in a linearly polarized light component in the direction perpendicular to said second direction.

6. The display device as claimed in claim 5, wherein said reflective polarizer further comprises a laminated product in which a first layer having birefringence and a second layer having a refractive index that is substantially equal to any one of a plurality of refractive indexes of said first layer and having no birefringence are alternately laminated.

7. The display device as claimed in claim 1, wherein said third polarized light separating means further comprises a reflective polarizer which transmits light of a linearly polarized light component in said third direction and which reflects light of a component of said second wavelength region Δ

λ

2 in a linearly polarized light component in a direction perpendicular to said third direction.

8. The display device as claimed in claim 7, wherein said reflective polarizer further comprises a laminated product in which a first layer having birefringence and a second layer having a refractive index that is substantially equal to any one of a plurality of refractive indexes of said first layer and having no birefringence are alternately laminated.

9. The display device as claimed in claim 1, wherein an angle formed by said second direction and said third direction is 45°

to 90°

.

10. The display device as claimed in claim 1, wherein an angle formed by said second direction and said third direction is 60°

to 90°

.

11. The display device as claimed in claim 1, wherein an angle formed by said second direction and said third direction is 75°

to 90°

.

12. The display device as claimed in claim 1, further comprising a transmissive light-diffusing layer between said variable transmission polarization axis means and said second polarized light separating means.

13. The display device as claimed in claim 1, further comprising a transmissive light-diffusing layer between said second polarized light separating means and said third polarized light separating means.

14. The display device as claimed in claim 1, further comprising a light-absorbing means on a side opposite to said second polarized light separating means with respect to said third polarized light separating means.

15. The display device as claimed in claim 1, further comprising a light source for illuminating said variable transmission polarization axis means.

16. The display device as claimed in claim 1, further comprising a reflecting means on a side opposite to said variable transmission polarization axis means of said first polarized light separating means.

17. An electronic apparatus comprising a display device as claimed in claim 1.

18. A polarized light separator, comprising:

one polarized light separating means which transmits light of a linearly polarized light component in one direction, and which reflects, of light of a linearly polarized light component in a predetermined direction different from said one direction, a component of a first wavelength region Δ

λ

1 and which transmits a component of a wavelength region -Δ

λ

1 different from said first wavelength component; and

another polarized light separating means which is located opposite to said one polarized light separating means, which transmits light of a linearly polarized light component in another direction, which reflects, of light of a linearly polarized light component in a predetermined direction different from another direction, a component of a second wavelength region Δ

λ

2 and which transmits a component of a wavelength region -Δ

λ

2 different from said second wavelength component.

19. A display device, comprising:

a variable transmission polarization axis optical element;

a first polarized light separator which is arranged on one side of said variable transmission polarization axis optical element, and which is of a type for effecting polarization separation by reflection or absorption;

a second polarized light separator which is placed on another side of said variable transmission polarization axis optical element, and which is of a type for effecting polarization separation by reflection for every wavelength of light; and

a third polarized light separator which is arranged on a side opposite to said variable transmission polarization axis optical element with respect to said second polarized light separator, and which is of a type for effecting polarization separation by reflection for every wavelength of light.

20. A display device comprising:

a variable transmission polarization axis device;

a first polarized light separator disposed on a first side of said variable transmission polarization axis device;

a second polarized light separator disposed on a second side of said variable transmission polarization axis device; and

a third polarized light separator disposed on a side of said second polarized light separator opposite said variable transmission polarization axis device;

wherein said first polarized light separator transmits a first linearly polarized light component and reflects or absorbs a second linearly polarized light component, said second polarized light separator transmits a third linearly polarized light component, reflects a fourth linearly polarized light component within a first wavelength region, and transmits said fourth lienarly polarized light component within a second wavelength region, and said third polarized light separator transmits a fifth linearly polarized light component, reflects a sixth linearly polarized light component within a third wavelength region, and transmits said sixth linearly polarized light component within a fourth wavelength region.

21. The display device of claim 20 further comprising a transmissive light diffuser disposed between said second polarized light separator and one of said variable transmissive polarization axis device and said third polarized light separator.

22. The display device of claim 20 further comprising a light absorber disposed on a side of said third polarized light separator opposite said second polarized light separator.

23. The display device of claim 20 further comprising a light source disposed proximate said variable transmission polarization axis device.

24. The display device of claim 20 further comprising a reflector disposed on a side of said first polarized light separator opposite said variable transmission polarization axis device.