Image display device

• US 9,905,997 B2
• Filed: 12/16/2016
• Issued: 02/27/2018
• Est. Priority Date: 01/12/2016
• Status: Active Grant

• Current Assignee: Panasonic Automotive Systems Company of America (Panasonic Holdings Corporation)
• Original Assignee: Panasonic Intellectual Property Management Co., Ltd. (Panasonic Holdings Corporation)
• Inventors: Furuya, Hiroyuki, Shiramizu, Takahisa
• Primary Examiner(s): Tan, Vibol
• Application Number:
  US15/381,941
• Publication Number:
  US 20170201068A1
• Time in Patent Office: 438 Days
• CPC Class Codes: G02B 2027/0112 comprising device for genereting colour display
• CPC Class Codes: G02B 26/0833 the reflecting element being a micromechanical device, e.g. a MEMS mirror, DMD G02B26/0825 takes precedence; micromechanical devices in general B81B
• CPC Class Codes: G02B 27/01 Head-up displays
• CPC Class Codes: G02B 27/0101 characterised by optical features G02B27/0172 takes precedence
• CPC Class Codes: H01S 5/06804 by monitoring an external parameter, e.g. temperature
• CPC Class Codes: H01S 5/4093 Red, green and blue [RGB] generated directly by laser action or by a combination of laser action with nonlinear frequency conversion

Abstract

An image display device includes a laser light source, a controller, a temperature acquisition unit, and an image forming unit. The laser light source emits a plurality of laser beams including a red laser beam, a green laser beam, and a blue laser beam. The controller controls lighting of the laser light source. The temperature acquisition unit obtains temperature information with respect to the laser light source. The image forming unit creates an image from the plurality of laser beams emitted from the laser light source. The controller varies a light output ratio between the plurality of laser beams, based on the temperature information obtained by the temperature acquisition unit.

Claims

1. An image display device comprising:

a laser light source that emits a plurality of laser beams including a red laser beam, a green laser beam, and a blue laser beam;

a controller that controls lighting of the laser light source;

a luminance switch that switches luminance of the laser light source;

a temperature acquisition unit that obtains temperature information with respect to the laser light source; and

an image forming unit that creates an image from the plurality of laser beams emitted from the laser light source, wherein;

the controller varies a light output ratio between the plurality of laser beams, based on the temperature information obtained by the temperature acquisition unit,

the luminance switch can select from two or more modes including a low-luminance mode and a high-luminance mode,

when selecting the high-luminance mode, the luminance switch causes the laser light source to emit the red laser light and the green laser light together, and

when selecting the low-luminance mode, the luminance switch causes the laser light source to emit the red laser light alone.

4. The image display device according to claim 1, further comprising a luminance acquisition unit that obtains external light intensity information with respect to light external to the image display device,

wherein the luminance switch selects from the two or more modes including the low-luminance mode and the high-luminance mode, based on the external light intensity information from the luminance acquisition unit.

5. The image display device according to claim 1, wherein in the low-luminance mode, the controller controls luminance by controlling an emission pulse width for the laser light source.

6. The image display device according to claim 1, wherein the red laser beam emitted from the laser light source has a central oscillation wavelength ranging from 650 nm to 655 nm inclusive at 25°

C.

7. The image display device according to claim 1, wherein the image forming unit is a two-dimensional micro electro mechanical systems (MEMS) mirror.

8. The image display device according to claim 1, wherein:

the image forming unit is a two-dimensional modulation element, and

the two-dimensional modulation element is driven in accordance with a field sequential system that sequentially emits red light, blue light, and green light to create a full-color display.

2. An image display device comprising:

a laser light source that emits a plurality of laser beams including a red laser beam, a green laser beam, and a blue laser beam;

a controller that controls lighting of the laser light source;

a luminance switch that switches luminance of the laser light source;

a temperature acquisition unit that obtains temperature information with respect to the laser light source; and

an image forming unit that creates an image from the plurality of laser beams emitted from the laser light source, wherein;

when a red color is displayed, the controller varies a light output ratio between the red laser beam and the green laser beam, based on the temperature information obtained by the temperature acquisition unit,

the luminance switch can select from two or more modes including a low-luminance mode and a high-luminance mode,

when selecting the high-luminance mode, the luminance switch causes the laser light source to emit the red laser light and the green laser light together, and

when selecting the low-luminance mode, the luminance switch causes the laser light source to emit the red laser light alone.

9. The image display device according to claim 2, further comprising a luminance acquisition unit that obtains external light intensity information with respect to light external to the image display device,

wherein the luminance switch selects from the two or more modes including the low-luminance mode and the high-luminance mode, based on the external light intensity information from the luminance acquisition unit.

10. The image display device according to claim 2, wherein in the low-luminance mode, the controller controls luminance by controlling an emission pulse width for the laser light source.

11. The image display device according to claim 2, wherein the red laser beam emitted from the laser light source has a central oscillation wavelength ranging from 650 nm to 655 nm inclusive at 25°

C.

12. The image display device according to claim 2, wherein the image forming unit is a two-dimensional micro electro mechanical systems (MEMS) mirror.

13. The image display device according to claim 2, wherein:

the image forming unit is a two-dimensional modulation element, and

the two-dimensional modulation element is driven in accordance with a field sequential system that sequentially emits red light, blue light, and green light to create a full-color display.

3. An image display device comprising:

a laser light source that emits a plurality of laser beams including a red laser beam, a green laser beam, and a blue laser beam;

a controller that controls lighting of the laser light source;

a luminance switch that switches luminance of the laser light source;

a temperature acquisition unit that obtains temperature information with respect to the laser light source; and

an image forming unit that creates an image from the plurality of laser beams emitted from the laser light source, wherein;

when a blue color is displayed, the controller varies a light output ratio between the blue laser light and the green laser light, based on the temperature information obtained by the temperature acquisition unit,

the luminance switch can select from two or more modes including a low-luminance mode and a high-luminance mode,

when selecting the high-luminance mode, the luminance switch causes the laser light source to emit the blue laser light and the green laser light together, and

when selecting the low-luminance mode, the luminance switch causes the laser light source to emit the blue laser light alone.

14. The image display device according to claim 3, wherein the red laser light emitted from the laser light source has a central oscillation wavelength ranging from 650 nm to 655 nm inclusive at 25°

C.

15. The image display device according to claim 3, wherein the image forming unit is a two-dimensional micro electro mechanical systems (MEMS) mirror.

16. The image display device according to claim 3, wherein:

the image forming unit is a two-dimensional modulation element, and

the two-dimensional modulation element is driven in accordance with a field sequential system that sequentially emits red light, blue light, and green light to create a full-color display.