Display device and electronic watch

• US 6,519,209 B1
• Filed: 03/03/2000
• Issued: 02/11/2003
• Est. Priority Date: 05/12/1998
• Status: Active Grant

• Current Assignee: Seiko Epson Corporation (Seiko Group)
• Original Assignee: Seiko Epson Corporation (Seiko Group)
• Inventors: Matsui, Tsuyoshi, Arikawa, Yasuo
• Primary Examiner(s): Miska, Vit
• Assistant Examiner(s): GOODWIN, JEANNE M
• Application Number:
  US09/462,665
• Time in Patent Office: 1,075 Days
• Field of Search: 368/82-84, 368/239-242, 349/96-100, 349/62, 349/97, 349/113-115, 359/487, 359/497, 359/500
• US Class Current: 368/242
• CPC Class Codes: G02F 1/1335 Structural association of cells with optical devices, e.g. polarisers or reflectors
• CPC Class Codes: G02F 1/133528 Polarisers
• CPC Class Codes: G02F 2203/34 Colour display without the use of colour mosaic filters

Abstract

In a display device, a light ray transmitted through an area which varies a polarization axis, and a light ray transmitted through an area which does not vary the polarization axis, respectively, become a linearly polarized light component (a first returning light ray) which is a specularly reflected from a specular reflecting element, and transmitted through a second polarization separator, a polarization changing element, and a first polarization separator, and a linearly polarized light component (a second returning light ray) which is specularly reflected by the second polarization separator, and transmitted through the polarization changing element and the first polarization separator. The first and second returning light rays present a background portion and a segment portion in a bright display. Both the first returning light ray and the second returning light ray are specularly reflected, presenting both the background portion and the segment portion in a mirror-like fashion. Specifically, the display device may present a display mode with both the background portion and the segment portion in a mirror-like image, a display mode with both the background portion and the segment portion in a matte image, or a display mode with one of the background portion and the segment portion in a mirror-like image and the other in a matte image. With a coloring element added, display modes are thus diversified by combining a diversity of tones combined with texture differences. Of the returning light which is reflected from the specular reflecting element, transmitted through the second polarization separator, the polarization changing element, and the first polarization separator, a linearly polarized light component, which is unable to be transmitted through the first polarization separator with the direction of its polarization axis deflected from a first direction, is reflected from a fourth polarization separator. Then, the linearly polarized light component repeats reflections between the reflecting element, the fourth polarization separator, and when the polarization axis of the linearly polarized light component becomes aligned with the first direction, the linearly polarized light component is transmitted through the first polarization element.

Claims

1. A display device comprising:

a first polarization separator which transmits a linearly polarized light component, of an incident light ray, aligned in a first direction, and which does not transmit a linearly polarized light component aligned in a direction perpendicular to the first direction,

a polarization changing element which selects one of a first state which varies a polarization axis of an incident linearly polarized light component when the incident linearly polarized light component is transmitted therethrough and a second state which does not vary the polarization axis when the incident linearly polarized light component is transmitted therethrough,

a second polarization separator which transmits a linearly polarized light component of an incident light ray aligned in a second direction, and which specularly reflects a linearly polarized light component aligned in a third direction perpendicular to the second direction, and

a specular reflecting element which specularly reflects a linearly polarized light component transmitted through the second polarization separator toward the second polarization separator,

the first polarization separator, the polarization changing element, the second polarization separator, and the specular reflecting element being arranged in order, and

the display device displaying predetermined information using a first returning light ray which is specularly reflected from the specular reflecting element and transmitted through the second polarization separator, the polarization changing element, and the first polarization separator, and a second light ray which is specularly reflected from the second polarization separator and transmitted through the polarization changing element and the first polarization separator, out of light rays which come in on the first polarization separator from a side of the first polarization separator diametrically opposite to the polarization changing element.

2. The display device according to claim 1, the specular reflecting element being a total reflection optical element that reflects all of or most of the linearly polarized light component incident thereon.

3. The display device according to claim 2, the total reflection optical element being a total reflection mirror that reflects all of or most of the linearly polarized light component incident thereon.

4. The display device according to claim 2, the total reflection optical element being a third polarization separator which reflects all of or most of the linearly polarized light component aligned in the second direction, and which does not reflect the linearly polarized light component align in a direction perpendicular to the second direction.

5. The display device according to claim 1, the specular reflecting element being a partially reflective optical element which specularly reflects a part of an incident linearly polarized light component, and which transmits a remaining incident linearly polarized light component.

6. The display device according to claim 5, the partially reflective optical element being a half mirror in which a metal thin film is formed on a surface of a light transmissive substrate.

7. The display device according to claim 5, the partially reflective optical element being a third polarization separator which transmits a linearly polarized light component aligned in a fourth direction and which specularly reflects a linearly polarized light component aligned in a fifth direction perpendicular to the fourth direction, and, because of a deflection between the fourth direction and the second direction, the third polarization separator specularly reflecting a part of a linearly polarized light component incident thereon and transmitting a part of the incident linearly polarized light component.

8. The display device according to claim 5, further comprising a light source for backlighting disposed diametrically opposite to the second polarization separator with respect to specular reflecting element which emits light toward the specular reflecting element,

the display device displaying predetermined information using a linearly polarized light component which is emitted from the backlighting light source, and which is transmitted through the specular reflecting element, the second polarization separator, the polarization changing element, and the first polarization separator.

9. The display device according to claim 1, further comprising a fourth polarization separator arranged between the first polarization separator and the polarization changing element which transmits a linearly polarized light component aligned in a sixth direction and which reflects a linearly polarized light component aligned in a seventh direction perpendicular to the sixth direction, the sixth direction being in a same direction as the first direction or is slightly deflected from the first direction.

10. The display device according to claim 1, further comprising a first light diffusing element disposed between the specular reflecting element and the second polarization separator which transmits an incident light ray and which diffuses the incident light ray.

11. The display device according to claim 10, further comprising a second light diffusing element disposed between the second polarization separator and the polarization changing element which transmits an incident light ray and which diffuses the incident light ray in a pattern different from a pattern of the first light diffusing element.

12. The display device according to claim 10, the first light diffusing element diffusing the light ray through fine surface roughness.

13. The display device according to claim 1, further comprising a first coloring element disposed between the specular reflecting element and the second polarization separator which colors an incident light ray to output a colored light ray.

14. The display device according to claim 13, the first coloring element being a color filter.

15. The display device according to claim 13, the first coloring element being a coloring layer attached on at least one polarization separator.

16. The display device according to claim 1, further comprising a second coloring element disposed between the first polarization separator and the second polarization separator which colors an incident light ray to output a colored light ray.

17. The display device according to claim 1, further comprising a first coloring element disposed between the specular reflecting element and the second polarization separator which colors an incident light ray to output a colored light ray, and a second coloring element disposed between the first polarization separator and the second polarization separator which colors an incident light ray to output a colored light ray with a hue different from a hue imparted by the first coloring element.

18. The display device according to claim 1, the polarization changing element comprising a liquid-crystal display element.

19. An electronic watch comprising the display device according to claim 1, the electronic watch displaying time and time measurement results in areas of the polarization changing element which are selected to be in a transmissive state which transmits the linearly polarized light component transmitted through the first polarization separator therethrough with a polarization axis of the linearly polarized light component varied, or in a transmissive state which transmits the linearly polarized light component therethrough with the polarization axis not varied.

20. The electronic watch according to according to claim 19, the electronic watch displaying time and time measurement results in a digital display in areas of the polarization changing element which are selected to be in a transmissive state which transmits the linearly polarized light component transmitted through the first polarization separator therethrough with the polarization axis of the linearly polarized light component varied, or in a transmissive state which transmits the linearly polarized light component therethrough with the polarization axis not varied.

21. The electronic watch according to according to claim 19, the electronic watch displaying time and time measurement results in an analog display pattern corresponding to a watch hand, in areas of the polarization changing element which are selected to be in a transmissive state which transmits the linearly polarized light component transmitted through the first polarization separator therethrough with the polarization axis of the linearly polarized light component varied, or in a transmissive state which transmits the linearly polarized light component therethrough with the polarization axis not varied.

22. The display device according to claim 1, further comprising:

a fourth polarization separator which is disposed between the first polarization separator and the polarization changing element, which transmits a linearly polarized light component of an incident light ray aligned in a same direction as the first direction, or aligned in a direction slightly deflected from the first direction, and which reflects a linearly polarized light component aligned in a direction perpendicular the first direction.

23. The display device according to claim 22, direction of the polarization axis of the linearly polarized light component transmitted through the third polarization separator forming angle of 20°

or smaller with the first direction.

24. The display device according to claim 22, a direction of the polarization axis of the linearly polarized light component transmitted through the third polarization separator forming an angle of 5°

or smaller with the first direction.

25. The display device according to claim 22, the second polarization separator reflecting a linearly polarized light component aligned in a third direction perpendicular to the second direction.

26. The display device according to claim 25, further comprising a second coloring element disposed between the first polarization separator and the second polarization separator which colors an incident light ray to output a colored light ray.

27. The display device according to of claim 25, further comprising a first coloring element disposed between the reflecting element and the second polarization separator which colors an incident light ray to output a colored light ray, and second coloring element disposed between the first polarization separator and the second polarization separator which colors an incident light ray to output a colored light ray with a hue different from a hue imparted by the first coloring element.

28. The display device according to claim 22, the reflecting element being a total reflection optical element which reflects all of or most of the linearly polarized light component incident thereon.

29. The display device according to claim 28, the total reflection optical element being a total reflection mirror which reflects all of or most of the linearly polarized light component incident thereon.

30. The display device according to claim 28, the total reflection optical element being a third polarization separator which reflects all of or most of the linearly polarized light component aligned in the second direction and which does not reflect the linearly polarized light component aligned in a direction perpendicular the second direction.

31. The display device according to claim 22, the reflecting element being a partially reflecting optical element which reflects a part of a linearly polarized light component incident thereon and which transmits a remaining incident linearly polarized light component.

32. The display device according to claims 31, the partially reflective optical element being a half mirror in which a metal thin film is formed on a surface of a light transmissive substrate.

33. The display device according to claim 31, the partially reflecting optical element being a third polarization separator which transmits a linearly polarized light component aligned in a fourth direction and which reflects a linearly polarized light component aligned in a fifth direction perpendicular to the fourth direction, and, because of a deflection between the fourth direction and the second direction, the fourth polarization separator reflecting a part of a linearly polarized light component incident thereon, and transmitting a part of the incident linearly polarized light component.

34. The display device according to claim 31, further comprising a light source for backlighting disposed diametrically opposite to the second polarization separator with respect to the reflecting element which emits light toward the reflecting element,

the display device displaying predetermined information using a linearly polarized light component which is emitted from the backlighting light source and transmitted through the reflecting element, the second polarization separator, the polarization changing element, and the first polarization separator.

35. The display device according to claim 22, further comprising a first light diffusing element disposed between the reflecting element and the second polarization separator which transmits an incident light ray and which diffuses the incident light ray.

36. The display device according to claim 35, further comprising a second light diffusing element disposed between the second polarization separator and the polarization changing element which transmits an incident light ray and which diffuses the incident light ray in a pattern different from a pattern imparted by the first light diffusing element.

37. The display device according to claim 35, the second light diffusing element diffusing the light ray through fine surface roughness.

38. The display device according to claim 22, further comprising a first coloring element disposed between the reflecting element and the second polarization separator which colors an incident light ray to output a colored light ray.

39. The display device according to claim 38, the first coloring element being a color filter.

40. The display device according to claim 38, the first coloring element being a coloring layer attached on at least one polarization separator.

41. The display device according to claim 22, the polarization changing element comprising a liquid-crystal display element.

42. An electronic watch comprising a display device according to claim 22, the electronic watch displaying time and time measurement results in areas of the polarization changing element which are selected to be in a transmissive state which transmits the linearly polarized light component transmitted through the first polarization separator therethrough with a polarization axis of the linearly polarized light component varied, or in a transmissive state which transmits the linearly polarized light component therethrough with the polarization axis not varied.

43. The electronic watch according to according to claim 42, the electronic watch displaying time and time measurement results in a digital display in areas of the polarization changing element which are selected to be in a transmissive state which transmits the linearly polarized light component transmitted through the first polarization separator therethrough with a polarization axis of the linearly polarized light component varied, or in a transmissive state which transmits the linearly polarized light component therethrough with the polarization axis not varied.

44. The electronic watch according to according to claim 42, the electronic watch displaying time and time measurement results in an analog display pattern corresponding to a watch hand in areas of the polarization changing element which are selected to be in a transmissive state which transmits the linearly polarized light component transmitted through the first polarization separator therethrough with a polarization axis of the linearly polarized light component varied, or in a transmissive state which transmits the linearly polarized light component therethrough with the polarization axis not varied.

45. The display device according to claim 1, further comprising a fourth polarization separator arranged between the first polarization separator and the polarization changing element which reflects a linearly polarized light component aligned in a sixth direction and which reflects a linearly polarized light component aligned in a seventh direction perpendicular to the sixth direction,

the sixth direction being in a same direction as the first direction or is slightly deflected from the first direction.