Display device and electronic apparatus using the same having a reflective polarizer between LCD and optical element which emits light responsive to light from polarizer

• US 6,233,029 B1
• Filed: 08/19/1997
• Issued: 05/15/2001
• Est. Priority Date: 08/23/1996
• Status: Expired due to Term

• Current Assignee: Seiko Epson Corporation (Seiko Group)
• Original Assignee: Seiko Epson Corporation (Seiko Group)
• Inventors: Iijima, Chiyoaki, Tsuchihashi, Toshihiko
• Primary Examiner(s): MALINOWSKI, WALTER J
• Application Number:
  US08/914,139
• Time in Patent Office: 1,365 Days
• Field of Search: 349/115, 349/96, 349/98, 349/101, 349/99, 349/71, 349/74, 349/80, 349/117
• US Class Current: 349/96
• CPC Class Codes: G02F 1/133374 for displaying permanent signs or marks
• CPC Class Codes: G02F 1/133514 Colour filters
• CPC Class Codes: G02F 1/133536 Reflective polarizers G02F1/13362 takes precedence
• CPC Class Codes: G02F 1/133543 Cholesteric polarisers
• CPC Class Codes: G02F 1/133545 Dielectric stack polarisers
• CPC Class Codes: G02F 2203/02 reflective

Abstract

A display device capable of obtaining a bright display is provided. A polarizer is arranged above an TN liquid crystal, a light-scattering layer, a polarized light separator, a coloring layer, and a reflecting plate are arranged under the TN liquid crystal. The polarized light separator transmits a linearly polarized light component of a second direction of light being incident from the upper side, reflects a linearly polarized light component of a third direction perpendicular to the second direction, and can upwardly emit linearly polarized light of the second direction in response to light being incident from the lower side. In a voltage non-applied portion, light reflected by the polarized light separator becomes white emission light. In a voltage applied portion, light transmitted through the polarized light separator is colored by the coloring layer to be color emission light.

Claims

1. A display device comprising:

transmission polarized light axis changing means for changing a transmission polarized light axis;

first and second polarized light separation means arranged on both sides of said transmission polarized light changing means holding said transmission polarized light changing means therebetween; and

an optical element arranged on an opposite side of said second polarized light separation means with respect to said transmission polarized light axis changing means, said optical element emitting light of a predetermined wavelength region toward said second polarized light separation means in response to light from said second polarized light separation means,

wherein said first polarized light separation means has first and second sides and emits light incident on the first side as linearly polarized light in a predetermined first direction from the second side, and emits light incident on the second side as linearly polarized light in the predetermined first direction from the first side, and

said second polarized light separation means has first and second sides, the first side facing the optical element, the second side facing the transmission polarized light axis changing means, the second polarized light separation means transmitting a linearly polarized light component in a predetermined second direction of light incident on the second side to said optical element, and reflecting a linearly polarized light component in a predetermined third direction perpendicular to the predetermined second direction of light incident on the second side to said transmission polarized light axis changing means, and emitting a linearly polarized light component in the second predetermined direction of light incident on the first side to said transmission polarized light axis changing means.

2. A display device according to claim 1, wherein said second polarized light separation means transmits a linearly polarized light component of the predetermined second direction of light incident on the second side over a substantially whole wavelength range of a visible light region to said optical element, reflects a linearly polarized light component in the predetermined third direction, and emits a linearly polarized light component in the second predetermined direction of light incident on the first side over the substantially whole wavelength range in the visible light region to said transmission polarized light axis changing means.

3. A display device according to claim 1, wherein said second polarized light separation means transmits a linearly polarized light component in the predetermined second direction of light incident on the second side to said optical element as linearly polarized light in the predetermined second direction.

4. A display device according to claim 1, wherein said second polarized light separation means is a laminate having a plurality of layers, adjacent ones of the layers having a same refractive index in the predetermined second direction and different refractive indexes in the predetermined third direction.

5. A display device according to claim 1, wherein said transmission polarized light axis changing means is a liquid-crystal element.

6. A display device according to claim 5, wherein said transmission polarized light axis changing means is a twisted nematic liquid-crystal element, a super-twisted nematic liquid-crystal element, or an electrically-controlled birefringence liquid-crystal element.

7. A display device according to claim 1, wherein said first polarized light separation means is a polarizer.

8. A display device according to claim 1, wherein said optical element absorbs light in wavelength regions other than the predetermined wavelength region of the light from said second polarized light separation means, reflects the light in the predetermined wavelength region toward said second polarized light separation means, and transmits the light in the predetermined wavelength region.

9. A display device according to claim 8, further comprising reflecting means arranged on an opposite side of said optical element with respect to said second polarized light separation means,

wherein said reflection means reflects at least the light in the predetermined wavelength region toward said optical element.

10. A display device according to claim 8, wherein said optical element is a color filter.

11. A display device according to according to claim 1, wherein said optical element emits light in the predetermined wavelength region in response to the light from said second polarized light separation means.

12. A display device according to claim 11, wherein said optical element is a fluorescent element.

13. A display device according to claim 1, wherein said optical element is a hologram which colors the light from said second polarized light separation means in the predetermined wavelength region.

14. A display device according to claim 1, further comprising a second optical element arranged on an opposite side of said second polarized light separation means with respect to said transmission polarized light axis changing means;

said second optical element emitting light in a predetermined second wavelength region different from the predetermined wavelength region toward said second polarized light separation means in response to light from said second polarized light separation means;

said display device including first and second display areas on a screen; and

said optical element being arranged corresponding to said first display area, and said second optical element being arranged corresponding to said second display area.

15. A display device according to claim 14, wherein said second optical element absorbs light in a wavelength region other than the predetermined second wavelength region of light from said second polarized light separation means, reflects light in the predetermined second wavelength region toward said second polarized light separation means, and transmits light in the predetermined second wavelength region.

16. A display device according to claim 14, wherein said second optical element emits light from said second polarized light separation means in the predetermined second wavelength region.

17. A display device according to claim 14, wherein said second optical element is a hologram which colors light from said second polarized light separation means in the predetermined second wavelength region.

18. A display device according to claim 1, further comprising first and second transparent substrates arranged on both sides of said transmission polarized light axis changing means to sandwich said transmission polarized light axis changing means therebetween,

wherein said first polarized light separation means is arranged on an opposite side of said first transparent substrate with respect to said transmission polarized light axis changing means, and

said second polarized light separation means is arranged on an opposite side of said second transparent substrate with respect to said transmission polarized light axis changing means.

19. A display device according to claim 18, wherein said first and second transparent substrates are glass substrates.

20. A display device according to claim 19, wherein a polychromatic display is performed in units of rows or characters in an icon portion or dots.

21. A display device according to claim 18, wherein said second transparent substrate is a plastic film substrate.

22. A display device according to claim 1, further comprising light-scattering means.

23. An electronic apparatus having a display device mounted thereon, comprising:

transmission polarized light axis changing means for changing a transmission polarized light axis;

first and second polarized light separation means arranged on both sides of said transmission polarized light changing means holding said transmission polarized light changing means therebetween; and

an optical element arranged on an opposite side of said second polarized light separation means with respect to said transmission polarized light axis changing means, said optical element emitting light of a predetermined wavelength region tow and said second polarized light separation means in response to light from said second polarized light separation means,

wherein said first polarized light separation means has first and second sides and emits light incident on the first side as linearly polarized light in a predetermined first direction from the second side, and emits light incident on the second side as linearly polarized light in the predetermined first direction from the first side, and

said second polarized light separation means has first and second sides, the first side facing the optical element, the second side facing the transmission polarized light axis changing means, the second polarized light separation means transmitting a linearly polarized light component in a predetermined second direction of light incident on the second side toward said optical element, and reflecting a linearly polarized light component in a predetermined third direction perpendicular to the predetermined second direction of light incident on the second side to said transmission polarized light axis changing means, and emitting a linearly polarized light component in the predetermined second direction of light incident on the first side to said transmission polarized light axis changing means.

24. A display device including liquid crystal positioned between first and second substrates comprising:

a polarizer disposed on an opposite side of said liquid crystal with respect to said first substrate, the polarizer transmitting light incident thereon in a predetermined direction;

a polarized light separator disposed on an opposite side of said liquid crystal with respect to said second substrate, said polarized light separator reflecting light or transmitting light, depending on a polarized direction of said light incident on said polarized light separator from said second substrate side; and

an optical element arranged on an opposite side of said a polarized light separator with respect to said second substrate, said optical element emitting colored light toward said polarized light separator in response to light from said polarized light separator.

25. A display device according to claim 24, said polarized light separator being capable of reflecting or transmitting light incident on said polarized light separator incident from said second substrate side, depending on a polarization direction of the incident light, said light being over substantially a whole wavelength range of a visible light region.

26. A display device according to claim 24, wherein said polarized light separator is a laminate having a plurality of layers, adjacent ones of the layers having a same refractive index in a predetermined direction and a different refractive index in a direction perpendicular to the predetermined direction.

27. A display device according to claim 24, said a polarized light separator being capable of reflecting or transmitting light incident on said polarized light separator depending on a polarization direction of the incident light, said light being over substantially a whole wavelength range of a visible light region.

28. A display device according to claim 24, said optical element being a fluorescent element.

29. A display device according to claim 24, said optical element being a color filter.

30. A display device according to claim 24, wherein said first and second substrates are substantially transparent and said first and second substrates are glass substrates.

31. A display device according to claim 24, said display device being a polychromatic display and displaying in units of rows or characters in an icon portion or dots.

32. A display device according to claim 24, wherein said second substrate is substantially transparent and said second substrate is a plastic film substrate.

33. A display device according to claim 24, further comprising:

a reflector arranged on an opposite side of said optical element with respect to said polarized light separator, said reflector reflecting light toward to said optical element.

34. A display device according to claim 24, further comprising a second optical element arranged on an opposite side of said polarized light separator with respect to said polarizer;

said second optical element emitting light in a second color different from the color emitted from said optical element toward said polarized light separator in response to light from said polarized light separator;

said display device including first and second display areas on a screen;

said optical element being arranged corresponding to said first display area, and said second optical element being arranged corresponding to said second display area.

35. A display device according to claim 24, said optical element being a hologram.

36. An electronic apparatus having a display device mounted thereon, said display device comprising:

liquid crystal positioned between first and second substrates;

a polarizer disposed on an opposite side of said liquid crystal with respect to said first substrate, the polarizer transmitting light incident thereon in a predetermined direction;

a polarized light separator disposed on an opposite side of said liquid crystal with respect to said second substrate, said polarized light separator reflecting light or transmitting light, depending on a polarization direction of said light incident on said polarized light separator from said second substrate side; and

an optical element arranged on an opposite side of said a polarized light separator with respect to said second substrate, said optical element emitting colored light toward to said polarized light separator in response to light from said polarized light separator.

37. A display device comprising:

a liquid crystal;

a polarizer disposed on a first side of said liquid crystal, the polarizer transmitting light incident thereon in a predetermined direction;

a polarized light separator disposed on a second side of said liquid crystal, said polarized light separator reflecting light or transmitting light, depending on a polarized direction of said light incident on said polarized light separator from said second side; and

a color filter arranged on an opposite side of said a polarized light separator with respect to said liquid crystal, said color filter emitting colored light toward said polarized light separator in response to light from said polarized light separator.

38. A display device according to claim 37, further comprising a second color filter arranged on an opposite side of said a polarized light separator with respect to said liquid crystal;

second color filter emitting colored light of a color different than the color of light emitted from said color filter toward said polarized light separator in response to light from said polarized light separator;

said display device including first and second display areas on a screen; and

said color filter being arranged corresponding to said first display area, and said second color filter being arranged corresponding to said second display area.

39. A display device according to claim 37, said polarized light separator being capable of reflecting or transmitting light incident on said polarized light separator incident from said liquid crystal, depending on a polarization direction of the incident light, said light being over substantially a whole wavelength range of a visible light region.

40. A display device according to claim 37, wherein said polarized light separator is a laminate having a plurality of layers, adjacent ones of the layers having a same refractive index in a predetermined direction and a different refractive index in a direction perpendicular to the predetermined direction.

41. A display device according to claim 37, said a polarized light separator being capable of reflecting or transmitting light incident on said polarized light separator depending on a polarization direction of the incident light, said light being over substantially a whole wavelength range of a visible light region.