Diffusion optical guide plate, and backlight source and liquid crystal display apparatus using the same

• US 5,956,107 A
• Filed: 09/12/1997
• Issued: 09/21/1999
• Est. Priority Date: 09/20/1996
• Status: Expired due to Term

• Current Assignee: Sharp Kabushiki Kaisha (Hon Hai Precision Industry Co., Ltd.)
• Original Assignee: Sharp Kabushiki Kaisha (Hon Hai Precision Industry Co., Ltd.)
• Inventors: Hashimoto, Yoshito, Mizushima, Shigeaki
• Primary Examiner(s): Sikes, William L.
• Assistant Examiner(s): NGUYEN, DUNG T
• Application Number:
  US08/928,856
• Time in Patent Office: 739 Days
• Field of Search: 349/62, 349/64, 349/65, 349/112, 349/68, 362/26, 362/31
• US Class Current: 349/64
• CPC Class Codes: G01D 11/28 Structurally-combined illuminating devices
• CPC Class Codes: G02B 6/0036 2-D arrangement of prisms, protrusions, indentations or roughened surfaces
• CPC Class Codes: G02B 6/0043 provided on the surface of the light guide
• CPC Class Codes: G02B 6/0046 Tapered light guide, e.g. wedge-shaped light guide
• CPC Class Codes: G02B 6/0051 Diffusing sheet or layer
• CPC Class Codes: G02B 6/0053 Prismatic sheet or layer; Brightness enhancement element, sheet or layer
• CPC Class Codes: G02F 1/1323 Arrangements for providing a switchable viewing angle
• CPC Class Codes: G02F 1/133504 Diffusing, scattering, diffracting elements associated to illuminating devices G02F1/133606
• CPC Class Codes: G02F 1/133615 Edge-illuminating devices, i.e. illuminating from the side

Abstract

The diffusion optical guide plate of this invention includes a transparent plate having the first plane, the second plane and side faces; and a light scattering controlling means for scattering incident light from said side face so as to allow the light to go out through the second plane, and transmitting incident light from said first plane so as to allow the light to go out through said second plane.

Claims

1. A diffusion optical guide plate, comprising:

a transparent plate having a first plane, a second plane and side faces; and

a light scattering controlling means for scattering incident light from said side face so as to allow the light to go out through the second plane, and transmitting incident light from said first plane so as to allow the light to go out through said second plane,

wherein said light scattering means comprises

a light scattering portion in a dot matrix shape disposed on or inside said transparent plate, and

a light absorbing portion or a light reflecting portion formed on the first plane corresponding to said light scattering portion.

2. A backlight source, comprising:

a diffusion optical guide plate having a transparent plate having a first plane, a second plane and side faces, and a light scattering controlling means for scattering incident light from said side face so as to allow the light to go out through the second plane and transmitting incident light from said first plane so as to allow the light to go out through said second plane;

a light-condensing shading slit film disposed at the first plane side of said diffusion optical guide plate;

an optical guide plate disposed on the surface of said shading slit film opposite to said diffusion optical guide plate; and

at least one light source for emitting light, the light selectively allowed to pass through either at least one side face of said diffusion optical guide plate or at least one side face of said optical guide plate, thereby varying an angle of the light passing through the second plane of the diffusion optical guide plate.

3. A backlight source according to claim 2, wherein said light scattering controlling means is a number of micro unevenness formed on said first plane.

4. A backlight source according to claim 2,

wherein the at least one light source comprises

a first light source and

a second light source,

the first light source provided on the side of said diffusion optical guide plate and

the second light source provided on the side of said optical guide plate,

said light sources selectively irradiating with light either the side face of said diffusion optical guide plate or the side face of said optical guide plate by an on-off operation of said light sources.

5. A backlight source, comprising:

a diffusion optical guide plate having a transparent plate having a first plane, a second plane and side faces, and a light scattering controlling means for scattering incident light from said side face so as to allow the light to go out through the second plane and transmitting incident light from said first plane so as to allow the light to go out through said second plane;

a light-condensing shading slit film disposed at the first plane side of said diffusion optical guide plate;

an optical guide plate disposed on the surface of said shading slit film opposite to said diffusion optical guide plate; and

light sources irradiating with light at least one side face of each of said diffusion optical guide plate and said optical guide plate,

wherein said light scattering controlling means comprises a light scattering portion disposed on or inside said transparent plate in a dot matrix shape, and a light absorbing portion or a light reflective portion formed on the first plane corresponding to said light scattering portion.

6. A backlight source, comprising:

a diffusion optical guide plate having a transparent plate having a first plane, a second plane and side faces, and a light scattering controlling means for scattering incident light from said side face so as to allow the light to go out through the second plane and transmitting incident light from said first plane so as to allow the light to go out through said second plane;

a light-condensing shading slit film disposed at the first plane side of said diffusion optical guide plate;

an optical guide plate disposed on the surface of said shading slit film opposite to said diffusion optical guide plate; and

light sources irradiating with light at least one side face of each of said diffusion optical guide plate and said optical guide plate,

wherein said diffusion optical guide plate and said optical guide plate have a sectional shape having a decreasing thickness from one side towards the other side, and are disposed so that the thinner side of said diffusion optical guide plate and the thicker side of said optical guide plate are located on the same side and the thicker side of said diffusion optical guide plate and the thinner side of said optical guide plate are located on the same side.

7. A backlight source, comprising:

a diffusion optical guide plate having a transparent plate having a first plane, a second plane and side faces, and a light scattering controlling means for scattering incident light from said side face so as to allow the light to go out through the second plane and transmitting incident light from said first plane so as to allow the light to go out through said second plane;

a light-condensing shading slit film disposed at the first plane side of said diffusion optical guide plate;

an optical guide plate disposed on the surface of said shading slit film opposite to said diffusion optical guide plate; and

light sources irradiating with light at least one side face of each of said diffusion optical guide plate and said optical guide plate,

further comprising an irradiation direction switching means for selectively irradiating with light either the side face of said diffusion optical guide plate or the side face of said optical guide plate.

8. A backlight source, comprising:

a diffusion optical guide plate having a transparent plate having a first plane, a second plane and side faces, and a light scattering controlling means for scattering incident light from said side face so as to allow the light to go out through the second plane and transmitting incident light from said first plane so as to allow the light to go out through said second plane;

a light-condensing shading slit film disposed at the first plane side of said diffusion optical guide plate;

an optical guide plate disposed on the surface of said shading slit film opposite to said diffusion optical guide plate; and

light sources irradiating with light at least one side face of each of said diffusion optical guide plate and said optical guide plate,

further comprising a light source transferring means for selectively irradiating with light either the side face of said diffusion optical guide plate or the side face of said optical guide plate.

9. A liquid crystal display apparatus having a backlight source, said backlight source comprising:

a diffusion optical guide plate comprising

a transparent plate having a first plane, a second plane and side faces, and

a light scattering controlling means for scattering incident light from said side face so as to allow the light to go out through the second plane and transmitting incident light from said first plane so as to allow the light to go out through said second plane;

a light-condensing shading slit film disposed at the first plane side of said diffusion optical guide plate;

an optical guide plate disposed on the surface of said shading slit film opposite to said diffusion optical guide plate; and

at least one light source for emitting light, the light selectively allowed to pass through either at least one side face of said diffusion optical guide plate or at least one side face of said optical guide plate, thereby varying an angle of the light passing through the second plane of the diffusion optical guide plate.

10. A liquid crystal display apparatus according to claim 9, wherein said light scattering controlling means is a micro unevenness formed on said first plane.

11. A liquid crystal display apparatus according to claim 9, further comprising the first light source provided on the side face of said diffusion optical guide plate and the second light source provided on the side of said optical guide plate, said light sources selectively irradiating with light either the side face of said diffusion optical guide plate or the side face of said optical guide plate by an on-off operation of said light sources.

12. A liquid crystal display apparatus having a backlight source, said backlight source comprising:

a diffusion optical guide plate comprising

a transparent plate having a first plane, a second plane and side faces, and

a light scattering controlling means for scattering incident light from said side face so as to allow the light to go out through the second plane and transmitting incident light from said first plane so as to allow the light to go out through said second plane;

a light-condensing shading slit film disposed at the first plane side of said diffusion optical guide plate;

an optical guide plate disposed on the surface of said shading slit film opposite to said diffusion optical guide plate; and

light sources irradiating with light at least one side face of each of said diffusion optical guide plate and said optical guide plate,

wherein said light scattering controlling means comprises a light scattering portion in a dot matrix shape disposed on or inside said transparent plate, and a light absorbing or light reflecting portion on the first plane corresponding to said light scattering portion in said first plane.

13. A liquid crystal display apparatus having a backlight source, said backlight source comprising:

a diffusion optical guide plate comprising

a transparent plate having a first plane, a second plane and side faces, and

a light scattering controlling means for scattering incident light from said side face so as to allow the light to go out through the second plane and transmitting incident light from said first plane so as to allow the light to go out through said second plane;

a light-condensing shading slit film disposed at the first plane side of said diffusion optical guide plate;

an optical guide plate disposed on the surface of said shading slit film opposite to said diffusion optical guide plate; and

light sources irradiating with light at least one side face of each of said diffusion optical guide plate and said optical guide plate,

wherein said diffusion optical guide plate and said optical guide plate have a sectional shape having a decreasing thickness from one side towards the other side, and are disposed so that the thinner side of said diffusion optical guide plate and the thicker side of said optical guide plate are located on the same side and the thicker side of said diffusion optical guide plate and the thinner side of said optical guide plate are located on the same side.

14. A liquid crystal display apparatus having a backlight source, said backlight source comprising:

a diffusion optical guide plate comprising

a transparent plate having a first plane, a second plane and side faces, and

a light scattering controlling means for scattering incident light from said side face so as to allow the light to go out through the second plane and transmitting incident light from said first plane so as to allow the light to go out through said second plane;

a light-condensing shading slit film disposed at the first plane side of said diffusion optical guide plate;

an optical guide plate disposed on the surface of said shading slit film opposite to said diffusion optical guide plate; and

light sources irradiating with light at least one side face of each of said diffusion optical guide plate and said optical guide plate,

further comprising an irradiation direction switching means for selectively irradiating with light either the side face of said diffusion optical guide plate or the side face of said optical guide plate.

15. A liquid crystal display apparatus having a backlight source, said backlight source comprising:

a diffusion optical guide plate comprising

a transparent plate having a first plane, a second plane and side faces, and

a light scattering controlling means for scattering incident light from said side face so as to allow the light to go out through the second plane and transmitting incident light from said first plane so as to allow the light to go out through said second plane;

a light-condensing shading slit film disposed at the first plane side of said diffusion optical guide plate;

an optical guide plate disposed on the surface of said shading slit film opposite to said diffusion optical guide plate; and

light sources irradiating with light at least one side face of each of said diffusion optical guide plate and said optical guide plate,

further comprising a light source transferring means for selectively irradiating with light either the side face of said diffusion optical guide plate or the side face of said optical guide plate.

16. A backlight source, comprising:

a diffusion optical guide plate having a first plane, a second plane and side faces;

a light-condensing means disposed at a first plane side of the diffusion optical guide plate for transmitting and condensing light toward the diffusion optical guide plate;

an optical guide plate disposed on the surface of said light-condensing means opposite to said diffusion optical guide plate; and

at least one light source for emitting light, the light selectively allowed to pass through either at least one side face of said diffusion optical guide plate or at least one side face of said optical guide plate, thereby varying an angle of the light passing through the second plane of the diffusion optical guide plate.

17. The backlight source according to claim 16,

wherein the diffusion optical guide plate comprises a transparent plate and a light scattering controlling means for scattering incident light from the side face so as to allow the light to pass through the second plane and transmitting incident light from said first plane so as to allow the light to pass through the second plane.

18. The backlight source according to claim 17,

wherein the light scattering controlling means is a shading slit film disposed at a first plane of the diffusion optical guide plate for transmitting and condensing light toward the diffusion optical guide plate.

19. A liquid crystal display apparatus having a liquid crystal display element and a backlight source disposed to incident light through the liquid crystal display element, the backlight source comprising:

a diffusion optical guide plate having a first plane, a second plane and side faces;

a light-condensing means disposed at a first plane side of the diffusion optical guide plate for transmitting and condensing light toward the diffusion optical guide plate;

an optical guide plate disposed on the surface of said light-condensing means opposite to said diffusion optical guide plate; and

at least one light source for emitting light, the light selectively allowed to pass through either at least one side face of said diffusion optical guide plate or at least one side face of said optical guide plate, thereby varying an angle of the light passing through the second plane of the diffusion optical guide plate.

20. The liquid crystal display apparatus according to claim 19,

wherein the diffusion optical guide plate comprises a transparent plate and a light scattering controlling means for scattering incident light from the side face so as to allow the light to go out through the second plane and transmitting incident light from said first plane so as to allow the light to go out through the second plane.

21. The liquid crystal display apparatus according to claim 20,

wherein the light scattering controlling means is a shading slit film disposed at a first plane of the diffusion optical guide plate for transmitting and condensing light toward the diffusion optical guide plate.