Laser Diode control method, laser Diode control device, and camcorder

• US 20080310468A1
• Filed: 05/28/2008
• Published: 12/18/2008
• Est. Priority Date: 06/12/2007
• Status: Abandoned Application

• Current Assignee: Hitachi, Ltd.
• Original Assignee: Hitachi, Ltd.
• Inventors: Nagashima, Kenichi
• Application Number:
  US12/156,011
• Publication Number:
  US 20080310468A1
• Time in Patent Office: Days
• US Class Current: 372/33
• CPC Class Codes: G11B 7/126 Circuits, methods or arrangements for laser control or stabilisation
• CPC Class Codes: H01S 5/0617 using memorised or pre-programmed laser characteristics
• CPC Class Codes: H01S 5/06804 by monitoring an external parameter, e.g. temperature

Abstract

A laser diode is controlled such that a writing operation can be performed readily even at a low temperature and equal to or below the operation guarantee temperature range of the laser diode. A laser diode control device includes a temperature sensor for detecting temperature of a laser diode. If a detected temperature by the temperature sensor is equal to or below the operation guarantee temperature range, a current equivalent to a threshold current value is supplied to the laser diode. After a predetermined time lapses, laser light is outputted to increase temperature of the laser diode to the operation guarantee temperature thereof. Finally, a writing operation is then carried out.

Claims

1. A laser diode control method used for a laser diode control device including a laser diode;

a drive device for driving the laser diode by supplying current for laser light output, and a temperature sensor, the method comprising the steps of;

detecting temperature around the laser diode;

supplying current equivalent to a threshold current value of the laser diode to the laser diode if temperature detected by the temperature sensor is equal to or below a predetermined value of the laser diode; and

outputting laser light after a predetermined amount of time lapses.

2. A laser diode control device, comprising:

a laser diode;

a drive device for driving the laser diode by supplying current for laser light output, the laser diode control device;

a temperature sensor for detecting temperature around the laser diode;

a memory for recording a threshold current value of the laser diode; and

control means for supplying a threshold current corresponding to temperature by the driving device to the laser diode on the basis of a temperature detected by the temperature sensor, and supplying a current for laser beam output to the laser diode after verifying that the temperature detected by the temperature sensor reached an operation guarantee temperature of the laser diode.

3. The laser diode control device according to claim 2, wherein the control means updates a current to be supplied to the laser diode at a predetermined interval, depending on temperature provided by the temperature sensor.

4. A camcorder, comprising:

a laser diode control device having a laser diode and a drive device for driving the laser diode by supplying current for laser light output, so as to record acquired video data onto a recording medium through the laser diode control device, the camcorder further including;

a temperature sensor for detecting temperature around the laser diode;

a memory for recording a threshold current value of the laser diode; and

control means for supplying a threshold current corresponding to temperature by the driving device to the laser diode on the basis of a temperature detected by the temperature sensor, and supplying a current for laser beam output to the laser diode after verifying that the temperature detected by the temperature sensor reached an operation guarantee temperature of the laser diode.

5. The camcorder according to claim 4, wherein the control means updates a current to be supplied to the laser diode at a predetermined interval, depending on temperature provided by the temperature sensor.