Long-life, high-efficiency laser apparatus having plurality of laser diode modules

Patent metadata

Field	Value
Publication number	US-9680289-B2
Application number	US-201615258074-A
Country	US
Kind code	B2
Filing date	Sep 7, 2016
Priority date	Sep 9, 2015
Publication date	Jun 13, 2017
Grant date	Jun 13, 2017

Abstract

A laser apparatus includes laser diode module groups (LDMGs) and power supply units and provides a laser light source by collecting laser beam from the LDMGs, and comprises: a driving current supply circuit network for injecting the driving currents into the respective LDMGs, independently; a control unit which controls the driving currents independently; a first recording unit in which are recorded data representing a relationship between the driving current and optical output power, and data representing a relationship between the driving current and drive voltage; and a first calculating unit which calculates the driving currents to be allocated to the LDMGs so as to achieve maximum electrical to optical conversion efficiency, wherein the control unit allocates the driving currents to the LDMGs in accordance with the results calculated by the first calculating unit so that the LDMGs as a whole can achieve maximum electrical to optical conversion efficiency under conditions.

First claim

The invention claimed is:

1. A laser apparatus which includes a plurality of laser diode module groups each containing at least one laser diode module, and a plurality of power supply units each for supplying a driving current to a corresponding one of the plurality of laser diode module groups, and which provides a laser light source or a pumping light source for laser oscillation by collecting laser beam from the plurality of laser diode module groups, the laser apparatus comprising:
a driving current supply circuit network which is capable of injecting the driving currents from the plurality of power supply units into the plurality of respective laser diode module groups, independently for each of the plurality of laser diode module groups;
a control unit which controls the driving currents to be injected from the plurality of power supply units into the plurality of respective laser diode module groups, independently for each of the plurality of laser diode module groups;
a first recording unit in which are recorded optical output power characteristic data representing a relationship between the driving current and optical output power for each of the plurality of laser diode module groups and current-voltage characteristic data representing a relationship between the driving current and drive voltage for each of the plurality of laser diode module groups; and
a first calculating unit which, in response to a laser beam output power command to the laser apparatus, calculates the driving currents to be allocated to the plurality of respective laser diode module groups so that the plurality of laser diode module groups as a whole can achieve maximum or substantially maximum electrical to optical conversion efficiency, wherein the electrical to optical conversion efficiency represents energy conversion efficiency from injected power to optical output power, under conditions where the commanded optical output power can be obtained, and wherein
in response to the laser beam output power command to the laser apparatus, the control unit allocates the driving currents to the plurality of respective laser diode module groups in accordance with results calculated by the first calculating unit based on the data recorded in the first recording unit so that the plurality of laser diode module groups as a whole can achieve maximum or substantially maximum electrical to optical conversion efficiency under conditions where the commanded optical output power can be obtained.

2. The laser apparatus according to claim 1 , wherein when the laser beam output power command to the laser apparatus is a pulse output command such that the optical output power alternates cyclically between a high output power level and a low output power level, the control unit allocates the driving currents to the plurality of respective laser diode module groups so that the plurality of laser diode module groups as a whole can achieve maximum or substantially maximum electrical to optical conversion efficiency under conditions where the commanded optical output power can be obtained, whether the optical output power is a high output power level or a low output power level.

3. The laser apparatus according to claim 1 , further comprising:
a second recording unit in which is recorded a data table of an acceleration-deceleration coefficient A(I) for driving-current-related life consumption speed, wherein the acceleration-deceleration coefficient A(I) is obtained by dividing the life expected of the plurality of laser diode module groups when the plurality of laser diode module groups are driven with a standard driving current I s by the life expected of the plurality of laser diode module groups when the plurality of laser diode module groups are driven with a driving current I;
a second calculating unit which calculates a time-integrated value=∫ t a t b A(I(t))dt from time t a to time t b for each of the plurality of laser diode module groups; and
a third recording unit which records a first accumulated value=∫ t 0 t p A(I(t))dt representing a result of the time integration performed up to present time t p by the second calculating unit for each of the plurality of laser diode module groups, and wherein:
when the control unit allocates, in response to the laser beam output power command, the driving currents to the plurality of respective laser diode module groups so that the plurality of laser diode module groups as a whole can achieve maximum or substantially maximum electrical to optical conversion efficiency under conditions where the commanded optical output power can be obtained, the plurality of laser diode module groups are compared with each other, and at least one of the plurality of laser diode module groups for which the first accumulated value is relatively small is preferentially selected as one of the plurality of laser diode module groups to which the driving currents are to be allocated.

4. The laser apparatus according to claim 3 , wherein when a difference or ratio between the first accumulated values of the plurality of laser diode module groups has expanded beyond a predetermined value, the first calculating unit and the control unit, in response to the laser beam output power command issued to the laser apparatus, allocate the driving currents to the plurality of respective laser diode module groups so that the plurality of laser diode module groups as a whole can achieve maximum electrical to optical conversion efficiency under conditions where the commanded optical output power can be obtained and under conditions where at least one of the plurality of laser diode module groups for which the first accumulated value is found to be relatively small as a result of comparing the plurality of laser diode module groups is selected as at least one of the plurality of laser diode module groups to which the driving currents are to be allocated.

5. The laser apparatus according to claim 3 , further comprising:
a sixth recording unit in which is recorded a data table providing correlation between remaining life of each of the plurality of laser diode module groups and a first performance characteristic of each of the plurality of laser diode module groups, wherein the first performance characteristic is calculated from the optical output power characteristic data and/or the current-voltage characteristic data recorded in the first recording unit for each of the plurality of laser diode module groups; and
a fourth calculating unit which calculates a correction coefficient C by dividing the remaining life of the plurality of laser diode module groups having standard first performance characteristic by the remaining life estimated from the first performance characteristic measured for each of the plurality of laser diode module groups and the data table recorded in the sixth recording unit, and wherein:
the second calculating unit not only calculates the time-integrated value=∫ t a t b A(I(t))dt for each of the plurality of laser diode module groups, but also calculates a time-integrated value=∫ t a t b C·A(I(t))dt by multiplying with the correction coefficient C, and the third recording unit records the value ∫ t 0 t p C·A(I(t))dt as a third accumulated value, in addition to the first accumulated value, and wherein when the control unit allocates the driving currents to the plurality of respective laser diode module groups, the plurality of laser diode module groups are compared with each other, and at least one of the plurality of laser diode module groups for which the third accumulated value is relatively small is preferentially selected as one of the laser diode module groups to which the driving currents are to be allocated, rather than preferentially selecting at least one of th

Assignees

• Fanuc Corp

Inventors

• Takigawa Hiroshi
• Machida Hisatada

Classifications

• H01S5/4025

  Array arrangements, e.g. constituted by discrete laser diodes or laser bar (H01S5/42 takes precedence) · CPC title

• H01S5/0683 Primary

  by monitoring the optical output parameters · CPC title

• H01S5/042 Primary

  Electrical excitation {; Circuits therefor (monolithically integrated laser drive components H01S5/0261)} · CPC title

• H01S5/06216

  Pulse modulation or generation · CPC title

• H01S3/09415

  the pumping beam being parallel to the lasing mode of the pumped medium, e.g. end-pumping · CPC title