Wavelength converter and two-dimensional image display device

• US 7,626,755 B2
• Filed: 01/30/2008
• Issued: 12/01/2009
• Est. Priority Date: 01/31/2007
• Status: Expired due to Fees

• Current Assignee: Panasonic Corporation (Panasonic Holdings Corporation)
• Original Assignee: Panasonic Corporation (Panasonic Holdings Corporation)
• Inventors: Furuya, Hiroyuki, Mizuuchi, Kiminori, Yamamoto, Kazuhisa
• Primary Examiner(s): Petkovsek; Daniel
• Application Number:
  US12/022,616
• Publication Number:
  US 20080212621A1
• Time in Patent Office: 671 Days
• Field of Search: 359326-332, 372/6
• US Class Current: 359/326
• CPC Class Codes: G02F 1/37 for second-harmonic generation G02F1/3532 takes precedence
• CPC Class Codes: H01S 3/0405 Conductive cooling, e.g. by heat sinks or thermo-electric elements
• CPC Class Codes: H01S 3/042 for solid state lasers H01S3/0401 takes precedence
• CPC Class Codes: H01S 3/06704 Housings; Packages
• CPC Class Codes: H01S 3/0675 Resonators including a grating structure, e.g. distributed Bragg reflectors [DBR] or distributed feedback [DFB] fibre lasers
• CPC Class Codes: H01S 3/094015 with pump light recycling, i.e. with reinjection of the unused pump light back into the fiber, e.g. by reflectors or circulators
• CPC Class Codes: H01S 3/09415 the pumping beam being parallel to the lasing mode of the pumped medium, e.g. end-pumping
• CPC Class Codes: H01S 3/1305 Feedback control systems
• CPC Class Codes: H01S 3/1306 Stabilisation of the amplitude

Abstract

A wavelength converter of the present invention is provided with a laser resonator including a fiber containing an laser-active material and a fiber grating formed in the fiber, a laser light source for emitting an excitation light to the fiber, and a wavelength conversion element for converting a fundamental wave of a laser beam emitted from the laser resonator into a harmonic, wherein the fiber is coiled and has the outer side thereof coated with a heat radiating member having a reflection surface for reflecting light having a wavelength of an excitation light. The wavelength converter is designed to prevent an efficiency reduction caused by the heat generation of a rare-earth doped fiber in a wavelength converter.

Claims

1. A wavelength converter, comprising:

a fiber laser resonator including a fiber containing a laser-active material and a fiber grating formed in the fiber;

a laser light source for emitting an excitation light to the fiber; and

a wavelength conversion element for converting a fundamental wave of a laser beam emitted from the fiber laser resonator into a harmonic,

wherein;

the fiber containing the laser-active material is coiled; and

at least a part of the outer surface of the fiber includes a reflection surface for reflecting light having the wavelength of the excitation light and is covered by a heat radiating member that radiates heat generated by the fiber.

2. A wavelength converter according to claim 1, wherein the heat radiating member is made of a sheet of metal.

3. A wavelength converter according to claim 1, wherein the heat radiating member is made of metal and is coated on the outer surface of the fiber.

4. A wavelength converter according to claim 3, further comprising:

a pair of resin films bonded to each other by compression; and

a heat transfer sheet;

wherein the heat radiating member coated on the fiber is accommodated between the pair of resin films and is held on the heat transfer sheet.

5. A wavelength converter according to claim 4, wherein a part of the heat transfer sheet is arranged outside the pair of resin films.

6. A wavelength converter according to claim 5, further comprising a heat sink provided in a part of the heat transfer sheet arranged outside the pair of resin films.

7. A wavelength converter according to claim 1, further comprising:

a pair of resin films bonded to each other by compression; and

a heat transfer sheet;

wherein the fiber is accommodated between the pair of resin films and is held on the heat transfer sheet.

8. A wavelength converter according to claim 7, wherein a part of the heat transfer sheet is arranged outside the pair of resin films.

9. A wavelength converter according to claim 8, further comprising a heat sink provided in a part of the heat transfer sheet arranged outside the pair of resin films.

10. A wavelength converter according to claim 7, wherein the heat transfer sheet is made of layered graphite.

11. A wavelength converter according to claim 7, wherein the heat transfer sheet has a groove, and the fiber includes a coiled part which is accommodated between the resin films and which is arranged in the groove.

12. A wavelength converter according to claim 1, wherein:

the fiber has a cladding diameter from 120 μ

m (inclusive) to 130 μ

m (inclusive) and a core diameter of 12 μ

m or shorter.

13. A wavelength converter according to claim 1, wherein:

the fiber has a cladding diameter from 120 μ

m (inclusive) to 130 μ

m (inclusive) and a core diameter of 10 μ

m or shorter; and

the fiber is coiled to have a diameter of 10 cm or shorter.

14. A wavelength converter according to claim 1, wherein the fiber contains Yb ions or Nd ions as the laser-active material.

15. A wavelength converter according to claim 1, wherein:

an oscillation wavelength of the laser light source is 900 nm (inclusive) to 980 nm (inclusive); and

the heat radiating member is made of metal containing aluminum or gold.

16. A wavelength converter according to claim 1, wherein:

an oscillation wavelength of the laser light source is 450 nm (inclusive) to 980 nm (inclusive); and

the heat radiating member is made of metal containing aluminum.

17. A wavelength converter according to claim 1, wherein:

the fiber includes a core, a cladding provided on the outer side of the core and a coating film provided on the outer side of the cladding; and

the heat radiating member is provided on the outer side of the coating film.

18. A wavelength converter according to claim 1, further comprising a temperature compensating mechanism for suppressing a dimensional change of the fiber in longitudinal, direction result from a temperature change, wherein the temperature compensating mechanism is located at a position corresponding to the fiber grating.

19. A 2D image display device, comprising:

the wavelength converter according to claim 1;

a mechanism for controlling a light quantity in accordance with luminance information of an inputted video signal, and controlling an average light quantity by applying a Pulse Width Modulation (PWM) control to a light source.