Light source device, optical device, and liquid-crystal display device

• US 6,547,400 B1
• Filed: 02/04/2000
• Issued: 04/15/2003
• Est. Priority Date: 06/04/1998
• Status: Expired due to Term

• Current Assignee: Seiko Epson Corporation (Seiko Group)
• Original Assignee: Seiko Epson Corporation (Seiko Group)
• Inventors: Yokoyama, Osamu
• Primary Examiner(s): Mathews, Alan A.
• Assistant Examiner(s): KOVAL, MELISSA J
• Application Number:
  US09/485,155
• Time in Patent Office: 1,166 Days
• Field of Search: 353/31, 353/37, 353/38, 353/94, 353/98, 349/5, 349/7, 345/39, 345/46, 345/82, 345/83
• US Class Current: 353/98
• CPC Class Codes: G02B 6/0018 Redirecting means on the surface of the light guide
• CPC Class Codes: G02B 6/005 provided by one optical element, or plurality thereof, placed on the light output side of the light guide
• CPC Class Codes: G02B 6/0068 Arrangements of plural sources, e.g. multi-colour light sources
• CPC Class Codes: G02B 6/0073 Light emitting diode [LED]
• CPC Class Codes: G02B 6/0096 the lights guides being of the hollow type
• CPC Class Codes: G02F 1/133524 Light-guides, e.g. fibre-optic bundles, louvered or jalousie light-guides
• CPC Class Codes: G02F 1/133603 with LEDs
• CPC Class Codes: G02F 1/133605 including specially adapted reflectors
• CPC Class Codes: G02F 1/133614 using photoluminescence, e.g. phosphors illuminated by UV or blue light
• CPC Class Codes: G02F 1/133622 Colour sequential illumination
• CPC Class Codes: G03B 21/2033 LED or laser light sources
• CPC Class Codes: G03B 21/204 using secondary light emission, e.g. luminescence or fluorescence using different colours G03B33/00; if related to video signals H04N9/3197
• CPC Class Codes: G03B 21/208 Homogenising, shaping of the illumination light
• CPC Class Codes: G03B 33/10 Simultaneous recording or projection G03B33/02, G03B33/04 G03B33/06 take precedence
• CPC Class Codes: H04N 5/7441 the modulator being an array of liquid crystal cells
• CPC Class Codes: H04N 9/3105 for displaying all colours simultaneously, e.g. by using two or more electronic spatial light modulators simultaneous projection in colour photography G03B33/10; beam splitting or combining systems per se G02B27/10
• CPC Class Codes: H04N 9/3155 for controlling the light source light source control per se H05B35/00 – H05B47/00; control of an illumination source for displays in general G09G3/3406
• CPC Class Codes: H04N 9/3164 using multiple light sources

Abstract

A light source device, comprising a light guide block that is provided with an inner wall capable of reflecting light and is shaped as a hollow component to form a light guide, and a point light source array that is located opposite one end face of the light guide block and is capable of emitting light into the light guide.

Claims

1. A light source device, comprising:

light guide means that is provided with mutually opposite end faces and that has a light guide function whereby light entering through one end face is guided to and emitted from the other end face; and

a point light source array that is a separate entity from said light guide means and that is obtained by arranging a plurality of point light sources arranged along two directions in a planar configuration along one of the end faces of the light guide means,

wherein an air layer is interposed between said point light source array and the light-entering end face of said light guide means.

2. A light source device as defined in claim 1, wherein the external shape of the end face for receiving light from said point light source array in said light guide means is substantially the same as the external shape of the end face for emitting the light.

3. A light source device as defined in claim 1, wherein said point light sources are light-emitting elements for emitting monochromatic light.

4. A light source device as defined in claim 1, wherein said point light source array is a combination of light-emitting elements of various colors.

5. A light source device as defined in claim 1, wherein substantially the same shapes are used for the external shape of the end face for emitting light in said light guide means, and the external shape of the illuminated surface of the illumination object illuminated with said emitted light.

6. A light source device as defined in claim 1, wherein said point light sources are light-emitting diodes.

7. An optical device, comprising:

a light source device as defined in claim 1; and

a member located opposite the end face for emitting the light of said light guide means and designed to modulate the light from said light guide means.

8. An optical device as defined in claim 7, wherein the external surface area of the end face for emitting light in said light guide means is substantially the same as the external surface area of the illuminated surface of the member for modulating the light from said light guide means.

9. A light source device, comprising the following separate entities:

a point light source array arranging a plurality of point light sources arranged along two directions in a planar configuration; and

light guide means in which light from the point light source array is admitted through at least one end, mixed, guided to the other end face, and emitted,

wherein an air layer is interposed between said point light source array and the light-receiving end face of said light guide means.

10. A light source device, comprising:

light guide means that is provided with mutually opposite end faces and that has a light guide function whereby light entering through one end face is guided to and emitted from the other end face; and

a point light source array that is a separate entity from said light guide means and that is obtained by arranging a plurality of point light sources in a planar configuration along one of the end faces of the light guide means,

wherein said light guide means comprises a hollow light guide body made of a transparent material,

wherein a reflecting metal surface is used as the surface of at least one end face inside the light guide means other than the end face for receiving light from said point light source array or the end face for emitting light in said hollow light guide body.

11. A light source device as defined in claim 10, wherein said reflecting surface comprises a curved surface.

12. A light source device, comprising:

light guide means that is provided with mutually opposite end faces and that has a light guide function whereby light entering through one end face is guided to and emitted from the other end face; and

a point light source array that is a separate entity from said light guide means and that is obtained by arranging a plurality of point light sources in a planar configuration along one of the end faces of the light guide means,

wherein said light guide means comprises a solid light guide body made of a transparent material,

wherein the surface of at least one side face of the light guide means other than the end face for receiving light from said point light source array or the end face for emitting light in said solid light guide body is a reflecting metal surface or a total reflection surface with respect to the light guided into the light guide means.

13. A light source device as defined in claim 12, wherein said reflecting surface comprises a curved surface.

14. A light source device, comprising:

light guide means that is provided with mutually opposite end faces and that has a light guide function whereby light entering through one end face is guided to and emitted from the other end face; and

a point light source array that is a separate entity from said light guide means and that is obtained by arranging a plurality of point light sources in a planar configuration along one of the end faces of the light guide means,

wherein said light guide means comprises a hollow light guide body or solid light guide body made of a transparent material,

wherein said reflecting surface comprises a plurality of flat reflecting surfaces, and said light guide body has a polygonal prismatic shape.

15. A light source device, comprising:

light guide means that is provided with mutually opposite end faces and that has a light guide function whereby light entering through one end face is guided to and emitted form the other end face; and

a point light source array that is a separate entity from said light guide means and that is obtained by arranging a plurality of point light sources in a planar configuration along one of the end faces of the light guide means,

wherein said light source device is so configured as to satisfy the relation L≧

P/(tan θ

), where L is the distance from the light-receiving side to the light-emitting side in the light guide means, P is the interval between adjacent point light sources in the point light source array, and θ

is the angle with the optical axis at a position in which the intensity of light radiated by a point light source is ½

the intensity of said light along the optical axis.

16. A liquid-crystal display device, comprising:

a light source device including;

(a) light guide means that is provided with mutually opposite end faces and that has a light guide function whereby light entering through one end face is guided to and emitted from the other end face; and

(b) a point light source array that is a separate entity from said light guide means and that is obtained by arranging a plurality of point light sources in a planar configuration along one of the end faces of the light guide means; and

a liquid-crystal display element located opposite the end face for emitting the light of said light guide means and designed to modulate the light emitted by said light guide means.

17. A liquid-crystal display device as defined in claim 16, further comprising a magnifying lens disposed in the optical path of the emitted light optically modulated by said liquid-crystal display element.

18. A liquid-crystal display device as defined in claim 17, further comprising a screen configured such that the image of said liquid-crystal display element can be projected by said magnifying lens.

19. A liquid-crystal display device as defined in claim 16, wherein the external surface area of the end face for emitting light in said light guide means is substantially the same as the external surface area of the display surface of said liquid-crystal display element.

20. A light source device, comprising:

a light guide block as a light guide means provided with an inner wall capable of reflecting light, and shaped as a hollow component to form a light guide; and

a point light source array composed of a plurality of point light sources that are capable of emitting light into said light guide and that are arranged along two directions in a planar configuration opposite one end face of the light guide block,

wherein an air layer is interposed between said point light source array and the light-entering end face of said light guide means.

21. A light source device as defined in claim 20, wherein said light guide block has a cylindrical shape in which said inner walls are composed of curved surfaces.

22. A light source device as defined in claim 20, wherein said point light sources are light-emitting diodes.

23. An optical device, comprising:

a light source device as defined in claim 20; and

a member located opposite the end face for emitting the light of said light guide block and designed to modulate the light from said light guide block.

24. An optical device as defined in claim 23, wherein the external surface area of the end face for emitting light in said light guide block is substantially the same as the external surface area of the illuminated surface of the member for modulating the light from said light guide block.

25. A light source device, comprising:

a light guide block as a light guide means provided with an inner wall capable of reflecting light, and shaped as a hollow component to form a light guide; and

a point light source array composed of a plurality of point light sources that are capable of emitting light into said light guide and that are arranged in a planar configuration opposite one end face of the light guide block,

wherein said light guide block has a polygonal prismatic shape in which said inner walls are composed of a plurality of flat reflecting surfaces.

26. A light source device, comprising:

a light guide block as a light guide means provided with an inner wall capable of reflecting light, and shaped as a hollow component to form a light guide; and

a point light source array composed of a plurality of point light sources that are capable of emitting light into said light guide and that are arranged in a planar configuration opposite one end face of the light guide block,

wherein said light guide block has a quadrangular prismatic shape comprising an end face on the side where said point light source array is disposed, an end face for emitting light opposite the end face where said point light source array is disposed, and four lateral surfaces corresponding to light-reflecting inner walls.

27. A liquid-crystal display device, comprising a light source device comprising:

(a) a light guide block as a light guide means provided with an inner wall capable of reflecting light, and shaped as a hollow component to form a light guide; and

(b) a point light source array composed of a plurality of point light sources that are capable of emitting light into said light guide and that are arranged in a planar configuration opposite one end face of the light guide block; and

a liquid-crystal display element located opposite the end face for emitting the light of said light guide block and configured to allow the light emitted by the light guide block to be modulated, wherein images can be viewed directly from the light emission side of the liquid-crystal display element.

28. A liquid-crystal display device, comprising a light source device comprising:

(a) a light guide block as a light guide means provided with an inner wall capable of reflecting light, and shaped as a hollow component to form a light guide; and

(b) a point light source array composed of a plurality of point light sources that are capable of emitting light into said light guide and that are arranged in a planar configuration opposite one end face of the light guide block;

a liquid-crystal display element disposed facing the other end face of said light guide block and configured such that light emitted by the light guide block can be modulated; and

a magnifying lens disposed in the optical path of the emitted light optically modulated by said liquid-crystal display element.

29. A liquid-crystal display device as defined in claim 28, further comprising a screen configured such that the image on said liquid-crystal display element can be projected by said magnifying lens.

30. A liquid-crystal display device, comprising:

a plurality of light source devices comprising;

(a) light guide means that is provided with mutually opposite end faces and that has a light guide function whereby light entering through one end face is guided to and emitted from the other end face; and

(b) a point light source array that is a separate entity from said light guide means and that is obtained by arranging a plurality of point light sources in a planar configuration along one of the end faces of the light guide means,

wherein said light source devices are so configured as to emit light within the wavelength region of each primary color,

color synthesis means which comprise, in accordance with each primary color, prescribed color modulation units comprising said light source devices and liquid-crystal display elements that are disposed facing the end face through which light is emitted by said light guide means and that are configured such that light emitted by said light guide can be modulated, and in which light emitted by the prescribed color modulation units can be synthesized; and

a projection lens disposed in the optical path of the emitted light synthesized by the color synthesis means.

31. A liquid-crystal display device as defined in claim 30, wherein said color synthesis means is a dichroic prism.

32. A liquid-crystal display device, comprising:

a light source device as defined in claim 31; and

a liquid-crystal display element located opposite the end face for emitting the light of said light guide means and designed to modulate light from the light guide body.

33. A liquid-crystal display device as defined in claim 32, comprising a projection lens located on the opposite side from the light guide body with respect to said liquid-crystal display element.

34. A liquid-crystal display device, comprising:

a plurality of light source devices comprising;

(a) light guide means that is provided with mutually opposite end faces and that has a light guide function whereby light entering through one end face is guided to and emitted from the other end face; and

(b) a point light source array that is a separate entity from said light guide means and that is obtained by arranging a plurality of point light sources in a planar configuration along one of the end faces of the light guide means,

wherein said light source devices emit white light,

color synthesis means which comprise, in accordance with each primary color, prescribed color modulation units comprising said light source devices, liquid-crystal display elements that are disposed facing the end face through which light is emitted by said light guide means and that are designed to modulate the light emitted by said light guide, and filters so configured as to be able to transmit light within the wavelength region of each primary color, and in which light emitted by the prescribed color modulation units can be synthesized; and

a projection lens disposed in the optical path of the emitted light synthesized by the color synthesis means.

35. A light source device, comprising:

a point light source array obtained by forming a planar configuration from a plurality of light-emitting elements for emitting light of the three primary colors; and

a light guide body which is a separate entity from said point light source array and in which light from said point light source array is admitted through one end face and is guided to the other end face

wherein an air layer is interposed between said point light source array and said light guide means.

36. A light source device as defined in claim 35, comprising a circuit for simultaneously or sequentially lighting up the light-emitting elements for emitting each color.

37. A light source device as defined in claim 35, wherein said light-emitting elements are light-emitting diodes.

38. An optical device, comprising:

a light source device as defined in claim 35; and

a member located opposite the end face for emitting the light of said light guide means and designed to modulate the light from said light guide means.

39. A light source device, comprising:

a point light source array obtained by forming a planar configuration from a plurality of light-emitting elements arranged along two directions for emitting monochromatic light; and

a light guide body in which light from the point light source array is admitted through one end face and is guided to the other end face;

further comprising a luminescent film located opposite the light-receiving surface or light-emitting surface of the light guide body and designed to convert said monochromatic light to white light,

wherein an air layer is interposed between said point light source array and said light guide means.

40. A light source device, comprising:

a point light source array obtained by forming a planar configuration from a plurality of light-emitting elements for emitting light of the three primary colors; and

a light guide body which is a separate entity from said point light source array and in which light from said point light source array is admitted through one end face and is guided to the other end face,

wherein said light guide body is hollow, and a reflecting metal surface is used as the surface of at least one end face inside said light guide body other than the end face for receiving light from said point light source array or the end face for emitting light.

41. A light source device, comprising:

a point light source array obtained by forming a planar configuration from a plurality of light-emitting elements for emitting light of the three primary colors; and

a light guide body which is a separate entity from said point light source array and in which light from said point light source array is admitted through one end face and is guided to the other end face,

wherein said light guide body is solid, and the surface of at least on side face of said light guide body other than the end face for receiving light from said point light source array or the end face for emitting light is a reflecting metal surface or a total reflection surface with respect to the light guided into said light guide body.

42. A light source device, comprising:

a point light source array obtained by forming a planar configuration from a plurality of light-emitting elements for emitting light of the three primary colors; and

a light guide body which is a separate entity from said point light source array and in which light from said point light source array is admitted through one end face and is guided to the other end face,

wherein said light source device is so configured as to satisfy the relation L≧

P/(tan θ

), where L is the distance from the light-receiving side to the light-emitting side in the light guide means, P is the interval between adjacent point light sources in the point light source array, and θ

is the angle with the optical axis at a position in which the intensity of light radiated by each light-emitting element is ½

the intensity of said light along the optical axis.

43. An optical device as defined in claim 42, wherein the external surface area of the end face for emitting light in said light guide means is substantially the same as the external surface area of the illuminated surface of the member for modulating the light from said light guide means.

44. A liquid-crystal display device, comprising:

a light source device comprising a point light source-array obtained by forming a planar configuration from a plurality of light-emitting elements for emitting light of the three primary colors, and a light guide body in which light from the point light source array is admitted through one end face and is guided to the other end face; and

a liquid-crystal display element located opposite the end face for emitting the light of said light guide body, said liquid-crystal display element modulating the light of each color and forming an image on the basis of image signals separated into individual colors in synchronism with the sequential lighting of said light-emitting elements of each color.