Light source device, illumination device liquid crystal device and electronic apparatus

• US 6,883,934 B2
• Filed: 07/12/2001
• Issued: 04/26/2005
• Est. Priority Date: 07/13/2000
• Status: Expired due to Term

• Current Assignee: BOE Technology Group Co., Ltd.
• Original Assignee: Seiko Epson Corporation (Seiko Group)
• Inventors: Kawakami, Hisanori, Endo, Kogo
• Primary Examiner(s): Husar, Stephen
• Assistant Examiner(s): Zeade, Bertrand
• Application Number:
  US09/904,177
• Publication Number:
  US 20020048163A1
• Time in Patent Office: 1,384 Days
• Field of Search: 362/261, 362/27, 362/555, 362/31, 362/561, 362/335, 362/339, 362/326, 362/340, 349/65, 385/33
• US Class Current: 362/261
• CPC Class Codes: G02B 6/0016 Grooves, prisms, gratings, scattering particles or rough surfaces
• CPC Class Codes: G02B 6/003 Lens or lenticular sheet or layer
• CPC Class Codes: G02B 6/0051 Diffusing sheet or layer
• CPC Class Codes: G02F 1/133615 Edge-illuminating devices, i.e. illuminating from the side

Abstract

A light source device 41A, 41B or 41C comprising a lens 44A, 44B or 44C which receives light from a light emitting device 43 such as LED. The lens 44A is a lens having the property that the directivity of exiting light in the Y direction is higher than the directivity in the X direction perpendicular to the Y direction. Namely, the light emitted from the light emitting device 43 is condensed in a narrow angular range in the Y direction, and is scattered in a wide angular range in the X direction. When the light source device 41A is used as a light source of an illumination device of a liquid crystal device, the height direction of a light guide in which the dimension is small coincides with the Y direction, and the width direction of the light guide in which the dimension is large coincides with the X direction.

Claims

1. An illumination device comprising:

a light source device which emits light; and

a light guide having a light receiving plane which receives light from the light source device and a light exiting plane which exits the light;

wherein the light source device comprises a light emitting device and a lens which is provided on a light emitting portion of the light emitting device and facing the light guide so as to condense the light emitted from the light emitting device on the light guide;

wherein the lens has a property that provides directivity of exiting light in one direction that is higher than directivity of exiting light in a direction perpendicular to the one direction, the one direction being set to a height direction of the light guide, and the perpendicular direction being set to a width direction of the light guide, the lens having a constant cross-section along a first axis thereof and a varying cross-section along a second axis thereof, the second axis being perpendicular to the first axis.

2. The illumination device according to claim 1, wherein the lens has a planar light incidence plane and a non-planar light exiting plane having a shape in which a height from the light incidence plane changes in one direction, while a height from the light incident plane is constant in a direction perpendicular to the one direction, the one direction being set to a height direction of the light guide, and the perpendicular direction being set to a width direction of the light guide, the lens having a constant cross-section along a first axis thereof and a varying cross-section along a second axis thereof, the second axis being perpendicular to the first axis.

3. The illumination source devices according to claim 1, wherein the lens has any one of a semicircular pillar shape, a prismatic shape, or a partial circular pillar shape having a Fresnel lens surface.

4. The illumination device according to claim 1, wherein the lens is provided adjacent the light receiving plane of the light guide, for condensing light.

10. The illumination source devices according to claim 2, wherein the lens has any one of a semicircular pillar shape, a prismatic shape, or a partial circular pillar shape having a Fresnel lens surface.

11. The illumination device according to claim 2, wherein the lens is provided adjacent the light receiving plane of the light guide, for condensing light.

17. The illumination device according to claim 1 wherein the illumination device comprises a lens which is provided on the light receiving plane of the light guide.

5. A liquid crystal device comprising:

a liquid crystal panel comprising a liquid crystal held between a pair of substrates; and

an illumination device for supplying light to the liquid crystal panel;

wherein the illumination device comprises a light source device which emits light, and a light guide having a light receiving plane which receives light from the light source device and a light exiting plane which exits the light; and

the light source device comprises a light emitting device and a lens which is provided on a light emitting portion of the light emitting device and facing the light guide so as to condense the light emitted from the light emitting device on the light guide;

wherein the lens has a property that provides directivity of exiting light in one direction that is higher than directivity of exiting light in a direction perpendicular to the one direction, the one direction in which the exiting light has higher directivity being set to a height direction of the light guide, and the perpendicular direction in which the exiting light has lower directivity being set to a width direction of the light guide, the lens having a constant cross-section along a first axis thereof and a varying cross-section along a second axis thereof, the second axis being perpendicular to the first axis.

6. The liquid crystal device according to claim 5, wherein the lens has a planar light incidence plane and a non-planar light exiting plane having a shape in which a height from the light incidence plane changes in one direction, while a height from the light incidence plane is constant in a direction perpendicular to the one direction, the one direction being set to a height direction of the light guide, and the perpendicular direction being set to a width direction of the light guide, the lens having a constant cross-section along a first axis thereof and a varying cross-section along a second axis thereof, the second axis being perpendicular to the first axis.

7. The liquid crystal device according to claim 5, wherein the lens has any one of a semicircular pillar shape, a prismatic shape, or a partial circular pillar shape having a Fresnel lens surface.

8. The liquid crystal device according to claim 5, wherein the lens is provided adjacent the light receiving plane of the light guide, for condensing light.

9. An electronic apparatus comprising a liquid crystal device, and a control circuit for controlling operation of the liquid crystal device, wherein the liquid crystal device comprises a liquid crystal device according claim 5.

12. The liquid crystal device according to claim 6, wherein the lens has any one of a semicircular pillar shape, a prismatic shape, or a partial circular pillar shape having a Fresnel lens surface.

13. The liquid crystal device according to claim 6, wherein the lens is provided adjacent the light receiving plane of the light guide, for condensing light.

14. An electronic apparatus comprising a liquid crystal device, and a control circuit for controlling operation of the liquid crystal device, wherein the liquid crystal device comprises a liquid crystal device according claim 6.

18. The illumination device according to claim 5 wherein the illumination device comprises a lens which is provided on the light receiving plane of the light guide.

15. A light source device comprising:

a base;

a light emitting device provided on a surface of the base;

a lens provided on a light emitting plane of the light emitting device and having a property that provides directivity of exiting light in one direction that is higher than directivity of exiting light in a direction perpendicular to the one direction; and

positioning means provided for precisely positioning the light source device relative to an object to which light emitted from the light emitting device is supplied.

16. A light source device comprising:

a base;

a light emitting device provided on a surface of the base;

a lens provided on a light emitting plane of the light emitting device and having a property that provides directivity of exiting light in one direction that is higher than directivity of exiting light in a direction perpendicular to the one direction; and

a plurality of positioning pins provided at predetermined positions of the base so as to precisely position the light source device relative to an object to which light emitted from the light emitting device is supplied.

19. A liquid crystal device comprising:

a liquid crystal panel comprising a liquid crystal held between a pair of substrates; and

an illumination device for supplying light to the liquid crystal panel;

wherein the illumination device comprises a light source device which emits light, and a light guide having a light receiving plane which receives light from the light source device and a light exiting plane which exits the light; and

the light source device comprises a light emitting device and a prismatic shaped lens facing the light guide so as to condense the light emitted from the light emitting device on the light guide;

wherein the lens has a property that provides directivity of exiting light in one direction that is higher than directivity of exiting light in a direction perpendicular to the one direction, the one direction in which the exiting light has higher directivity being set to a height direction of the light guide, and the perpendicular direction in which the exiting light has lower directivity being set to a width direction of the light guide, the tens having a constant cross-section along a first axis thereof and a varying cross-section along a second axis thereof, the second axis being perpendicular to the first axis.

20. A liquid crystal device comprising:

a liquid crystal panel comprising a liquid crystal held between a pair of substrates; and

an illumination device for supplying light to the liquid crystal panel;

wherein the illumination device comprises a light source device which emits light, and a light guide having a light receiving plane which receives light from the light source device and a light exiting plane which exits the light; and

the light source device comprises a light emitting device and a partial circular pillar shaped lens having a Fresnel lens surface which is facing the light guide so as to condense the light emitted from the light emitting device on the light guide;

wherein the lens has a property that provides directivity of exiting light in one direction that is higher than directivity of exiting light in a direction perpendicular to the one direction, the one direction in which the exiting light has higher directivity being set to a height direction of the light guide, and the perpendicular direction in which the exiting light has lower directivity being set to a width direction of the light guide, the lens having a constant cross-section along a first axis thereof and a varying cross-section along a second axis thereof, the second axis being perpendicular to the first axis.