SURFACE ILLUMINATOR AND LIQUID CRYSTAL DISPLAY USING SAME

• US 20090303417A1
• Filed: 11/15/2006
• Published: 12/10/2009
• Est. Priority Date: 11/15/2005
• Status: Active Grant

• Current Assignee: Panasonic Corporation (Panasonic Holdings Corporation)
• Original Assignee: Panasonic Corporation (Panasonic Holdings Corporation)
• Inventors: Itoh, Tatsuo, Kadowaki, Shin-ichi, Mizuuchi, Kiminori, Kasazumi, Ken'ichi, Mizushima, Tetsuro, Yamamoto, Kazuhisa
• Granted Patent: US 7,969,532 B2
• Time in Patent Office: Days
• US Class Current: 349/65
• CPC Class Codes: G02B 19/0028 refractive and reflective surfaces, e.g. non-imaging catadioptric systems
• CPC Class Codes: G02B 19/0057 in the form of a laser diode array, e.g. laser diode bar semiconductor laser arrays with beam combining arrangement H01S5/4012
• CPC Class Codes: G02B 26/105 with one or more pivoting mirrors or galvano-mirrors G02B26/101 takes precedence
• CPC Class Codes: G02B 27/1053 having a single light modulator for all colour channels
• CPC Class Codes: G02B 27/1086 operating by diffraction only
• CPC Class Codes: G02B 27/144 using partially transparent surfaces without spectral selectivity G02B27/147 takes precedence
• CPC Class Codes: G02B 27/145 having sequential partially reflecting surfaces
• CPC Class Codes: G02B 27/48 Laser speckle optics
• CPC Class Codes: G02B 3/0056 arranged along two different directions in a plane, e.g. honeycomb arrangement of lenses G02B3/0043 takes precedence; miniaturised objectives for electronic devices employing wafer level optics G02B13/0085
• CPC Class Codes: G02B 5/02 Diffusing elements; Afocal elements
• CPC Class Codes: G02B 6/0028 Light guide, e.g. taper
• CPC Class Codes: G02B 6/0066 characterised by the light source being coupled to the light guide
• CPC Class Codes: G02F 1/133621 providing coloured light G02F1/133617, G02F1/133533 take precedence

Abstract

The present invention provides a surface illuminator having a uniform luminance over a large area by using a laser light source, having a wide color reproduction range, and capable of suppressing a speckle noise, as well as a liquid crystal display using the same. The surface illuminator of the present invention includes the laser light source that emits a laser beam; a beam scan section that deflects and scans the laser beam; and a first plate-shaped light guide that makes the laser beam deflected and scanned by the beam scan section to be incident from an end face portion and making the incident laser beam to emit from a first major surface. Further, the liquid crystal display of the present invention includes a liquid crystal display panel and the surface illuminator, wherein the surface illuminator is used as a backlight illuminator that lights the liquid crystal display panel from backside in this liquid crystal display.

Claims

1. A surface illuminator comprising:

a laser light source that emits a laser beam;

a beam scan section that deflects and scans the laser beam; and

a first plate-shaped light guide that makes the laser beam which is deflected and scanned by said beam scan section to be incident from an end face portion and makes the incident laser beam to emit from a first major surface.

2. The surface illuminator according to claim 1, further comprising:

a optical path conversion section that receives the laser beam emitted from said beam scan section without leakage, then converts an optical path of the laser beam, and emits the received laser beam to said first light guide without leakage, wherein

the laser beam emitted from the optical path conversion section is incident to said first light guide from its end face portion and is emitted from the first major surface.

3. The surface illuminator according to claim 2, further comprising:

a second plate-shaped light guide that receives the laser beam emitted from said beam scan section without leakage and guides the received laser beam to said optical path conversion section without leakage, wherein

the second light guide is provided to laminate on a second major surface of said first light guide which is different from the first major surface of said first light guide;

said beam scan section and said optical path conversion section are disposed in the vicinity of an end face portion of said second light guide;

said beam scan section makes the deflected and scanned laser beam to be incident onto the end face portion of said second light guide; and

said optical path conversion section receives the laser beam emitted from the end face portion of said second light guide without leakage.

4. The surface illuminator according to claim 1, wherein said first light guide includes a deflection sheet on the first major surface that deflects an advancing direction of the laser beam.

5. The surface illuminator according to claim 4, wherein said deflection sheet includes at least any one of a diffusion plate, a lens sheet, and a prism sheet.

6. The surface illuminator according to claim 1, wherein said beam scan section includes a reflection mirror that reflects the laser beam, and an angle adjusting mechanism that changes an angle of said reflection mirror, and by changing the angle of the reflection mirror by said angle adjusting mechanism, the laser beam is deflected and scanned.

7. The surface illuminator according to claim 1, comprising:

at least one of a cylindrical lens and a lenticular lens; and

a reciprocally moving mechanism that reciprocally moves said at least one of the cylindrical lens and lenticular lens in a direction parallel to the end face portion of said first light guide, wherein

the deflection scanning is executed by the reciprocal movement of said said at least one of the cylindrical lens and lenticular lens,

said at least one of the cylindrical lens and lenticular lens changes a deflection direction of the laser beam in time sequence such that the laser beam has a uniform light intensity distribution.

8. The surface illuminator according to claim 1, wherein said beam scan section includes an optical element that expands the laser beam in a direction parallel to the first major surface of said first light guide.

9. The surface illuminator according to claim 1, further comprising:

a vertical angle oscillation mechanism that oscillates an emission angle of the laser beam in a direction vertical to said first major surface of said first light guide, wherein

the deflection scanning is executed by oscillation of the emission angle by said vertical angle oscillation mechanism.

10. The surface illuminator according to claim 2, wherein said optical path conversion section includes an optical element that almost parallelizes an advancing direction of the incident laser beam.

11. The surface illuminator according to claim 1, wherein said laser light source includes a light source that emits a red laser beam, a green laser beam, and a blue laser beam at least, and said laser light source multiplexes the red laser beam, the green laser beam, and the blue laser beam and emits the multiplexed beams to said beam scan section.

12. The surface illuminator according to claim 1, wherein said light source includes a light source that emits laser beams having wavelengths different from one another and including a red laser beam, a green laser beam, and a blue laser beam at least, and said beam scan section individually deflects and scans the laser beams having the wavelengths different from one another.

13. The surface illuminator according to claim 12, wherein

said beam scan section further includes a controlling section that controls the individual deflection by said beam scan section, said controlling section controls the individual deflection such that the laser beams of the wavelengths different from one another are propagated through mutually different regions of said first light guide at the same time and each of the laser beams of the wavelengths different from one another is propagated through.

14. A liquid crystal display comprising a liquid crystal display panel and a backlight illuminator that lights said liquid crystal display panel from a back surface side, said backlight illuminator including:

a laser light source that emits a laser beam;

a beam scan section that deflects and scans the laser beam; and

a first plate-shaped light guide that makes the laser beam which is deflected and scanned by said beam scan section to be incident from an end face portion and making the incident laser beam to emit from a first major surface, wherein

said first major surface of said first light guide of said backlight illuminator and said liquid crystal display panel are disposed in closely contact with each other, and

the laser beam emitted from said first major surface lights said liquid crystal display panel.

15. The liquid crystal display according to claim 14, wherein said backlight illuminator further comprises an optical path conversion section that receives the laser beam emitted from said beam scan section without leakage, then converts an optical path of the laser beam, and emits the received laser beam to said first light guide without leakage, and said first light guide makes the laser beam which is emitted from said optical path conversion section to be incident from said end face portion and makes the incident laser beam to emit from said first major surface.

16. The liquid crystal display according to claim 15, wherein said backlight illuminator further comprises a second plate-shaped light guide that receives the laser beam which is emitted from said beam scan section without leakage and guides the received laser beam to said optical path conversion section without leakage;

said second light guide is disposed to laminate on a second major surface of said first light guide which is different from said first major surface of said first light guide;

said beam scan section and said optical path conversion section are disposed in the vicinity of said end face portion of said second light guide;

said beam scan section makes the deflected and scanned laser beam to be incident onto said end face portion of said second light guide; and

said optical path conversion section receives the laser beam which is emitted from said end face portion of said second light guide without leakage.

17. The liquid crystal display according to claim 14, wherein said first light guide includes a deflection sheet that deflects an advancing direction of the laser beam to said first major surface.

18. The liquid crystal display according to claim 17, wherein said deflection sheet includes at least any one of a diffusion plate, a lens sheet, and a prism sheet.

19. The liquid crystal display according to claim 15, wherein said optical path conversion section further includes an optical element that almost parallelizes an advancing direction of the incident laser beam.

20. The liquid crystal display according to claim 14, wherein a second major surface of said first light guide of said backlight illuminator includes a reflection surface having irregularity that reflects the laser beam and makes the laser beam to emit from said first major surface.

21. The liquid crystal display according to claim 14, wherein said beam scan section includes a reflection mirror that reflects the laser beam and an angle adjusting mechanism that changes an angle of said reflection mirror, and said angle adjusting mechanism changes the angle of said reflection mirror and deflects and scans the laser beam.

22. The liquid crystal display according to claim 14, wherein said beam scan section further includes a vertical angle oscillation mechanism that oscillates an emission angle of the laser beam in a direction vertical to said first major surface, and the deflection scanning is executed by oscillation of the emission angle by said vertical angle oscillation mechanism.

23. The liquid crystal display according to claim 14, wherein said beam scan section includes at least one of a cylindrical lens and a lenticular lens, and a reciprocally moving mechanism that reciprocally moves said at least one of the cylindrical lens and the lenticular lens in a direction parallel to said end face portion of said first light guide, and the deflection scanning is executed by the reciprocal movement of said at least one of the cylindrical lens and lenticular lens,

said at least one of the cylindrical lens and lenticular lens changes a deflection direction of the laser beam in time sequence such that the laser beam has a uniform light intensity distribution.

24. The liquid crystal display according to claim 14,

said liquid crystal display panel includes a pixel, wherein

said pixel include a plurality of sub-pixels that display colors different from one another, and

said first light guide includes a launching element that emits a laser beam from said first major surface to said sub-pixels corresponding to each color to be displayed by said sub-pixels.

25. The liquid crystal display according to claim 14, wherein

said laser bean source includes a light source that emits a red laser beam, a green laser beam, and a blue laser beam at least;

and

said laser light source multiplexes the red laser beam, green laser beam, and blue laser beam, and emits the multiplexed laser beam to said beam scan section.

26. The liquid crystal display according to claim 14, wherein

said laser light source includes a light source that emits laser beams having wavelengths different from one another, including a red laser beam, a green laser beam and a blue laser beam at least, and

said beam scan section deflects and scans each laser beam having the wavelengths different from one another.

27. The liquid crystal display according to claim 26, wherein

said beam scanning section

further includes a controlling section that controls the individual deflection by said beam scan section,

said controlling section controls the individual deflection such that the laser beams of the wavelengths different from one another are propagated through mutually different regions of said first light guide at the same time and each of the laser beams of the wavelengths different from one another is propagated through a common region of said first light guide at different times.

28. The liquid crystal display according to claim 27, wherein

said liquid crystal display panel includes a plurality of pixels,

said pixel makes a laser beam to be incident thereon at a first time, which has a first wavelength and is included in the laser beams having wavelengths different from one another, and makes a laser beam to be incident thereon at a second time, which has a second wavelength and is included in the laser beams having wavelengths different from one another, and

one pixel of said pixels displays a plurality of colors.

29. The liquid crystal display according to claim 14,

said liquid crystal display panel includes a pixel,

wherein at least any one of a diffusion plate, a lens sheet, and a prism sheet is provided on a lower stream side of said pixel along an advancing direction of the laser beam.