Laser machining apparatus that irradiates laser beam for machining surface of workpiece

1. A laser machining apparatus comprising:

a pump light emitting device configured to emit pump light upon receipt of a drive current, the pump light having intensity corresponding to a current value of the drive current;

a laser beam emitting device configured to transit to a pumped state to emit a laser beam for machining a workpiece when the pump light is incident from the pump light emitting device, the laser beam emitting device being configured to emit the laser beam having prescribed beam intensity during machining the workpiece;

a scanner configured to scan the laser beam emitted from the laser beam emitting device at a scanning speed; and

a controller configured to perform:

(a) supplying an initial drive current having an initial drive current value to the pump light emitting device during an initial drive current supply period, the initial drive current supply period being made up with a first period and a second period subsequent to the first period, the first period being shorter than the initial drive current supply period, the pump light emitting device emitting the pump light having initial light intensity upon receipt of the initial drive current;

(b) controlling the scanner to start scanning the laser beam after the first period has elapsed from a start of supplying the initial drive current in (a); and

(c) supplying a prescribed drive current having a prescribed drive current value to the pump light emitting device after the second period has elapsed from a start of scanning the laser beam in (b), the prescribed drive current value being smaller than the initial drive current value, the pump light emitting device emitting the pump light having prescribed light intensity upon receipt of the prescribed drive current, the laser beam emitting device emitting the laser beam having the prescribed beam intensity when the pump light having the prescribed light intensity is incident upon the laser beam emitting device.

2. The laser machining apparatus according to claim 1 , wherein the controller is configured to further perform:

(d) accepting data related to machining conditions; and

(e) determining an amount of electric power to be supplied to the pump light emitting device in accordance with the machining conditions.

3. The laser machining apparatus according to claim 2 , wherein the machining conditions include the scanning speed of the scanner.

4. The laser machining apparatus according to claim 2 , wherein the machining conditions include a material of the workpiece.

5. The laser machining apparatus according to claim 2 , wherein the controller is configured to further perform:

(f) changing the initial drive current supply period in accordance with the determined amount of the electric power by changing the second period while maintaining the first period.

6. The laser machining apparatus according to claim 1 , wherein the controller is configured to further perform:

(g) determining whether machining of the workpiece with the laser beam has been performed;

(h) in response to determining that the machining has been performed, determining whether a predetermined idle period starting from an end of the machining has elapsed;

(i) in response to determining that the predetermined idle period has elapsed, supplying the initial drive current to the pump light emitting device during the initial drive current supply period; and

(j) controlling the scanner to start scanning the laser beam after the first period has elapsed from a start of supplying the initial drive current in (i).

7. The laser machining apparatus according to claim 1 , further comprising a detector configured to detect a property of the laser beam emitted from the laser beam emitting device;

wherein the controller is configured to further perform:

(k) determining the first period in accordance with the property of the laser beam.

8. The laser machining apparatus according to claim 7 , wherein the laser beam emitting device is configured to emit the laser beam in a cycle,

wherein the detector is configured to detect a cycle of the laser beam, and

wherein the first period is determined so that the cycle of the laser beam is smaller than a prescribed cycle.

9. The laser machining apparatus according to claim 8 , wherein the first period is longer than 20 μsec.

10. A non-transitory computer readable storage medium storing a set of program instructions for a laser machining apparatus including: a pump light emitting device configured to emit pump light upon receipt of a drive current, the pump light having intensity corresponding to a current value of the drive current; a laser beam emitting device configured to transit to a pumped state to emit a laser beam for machining a workpiece when the pump light is incident from the pump light emitting device, the laser beam emitting device being configured to emit the laser beam having prescribed beam intensity during machining the workpiece; a scanner configured to scan the laser beam emitted from the laser beam emitting device; and a controller, the set of program instructions, when executed by the controller, causing the laser machining apparatus to perform:

(a) supplying an initial drive current having an initial drive current value to the pump light emitting device during an initial drive current supply period, the initial drive current supply period being made up with a first period and a second period subsequent to the first period, the first period being shorter than the initial drive current supply period, the pump light emitting device emitting the pump light having initial light intensity upon receipt of the initial drive current;

(b) controlling the scanner to start scanning the laser beam after the first period has elapsed from a start of supplying the initial drive current in (a), and

(c) supplying a prescribed drive current having a prescribed drive current value to the pump light emitting device after the second period has elapsed from a start of scanning the laser beam in (b), the prescribed drive current value being smaller than the initial drive current value, the pump light emitting device emitting the pump light having prescribed light intensity upon receipt of the prescribed drive current, the laser beam emitting device emitting the laser beam having the prescribed beam intensity when the pump light having the prescribed light intensity is incident upon the laser beam emitting device.

11. A method for controlling a laser machining apparatus including: a pump light emitting device configured to emit pump light upon receipt of a drive current, the pump light having intensity corresponding to a current value of the drive current; a laser beam emitting device configured to transit to a pumped state to emit a laser beam for machining a workpiece when the pump light is incident from the pump light emitting device, the laser beam emitting device being configured to emit the laser beam having prescribed beam intensity during machining the workpiece; a scanner configured to scan the laser beam emitted from the laser beam emitting device; and a controller, the method comprising:

(a) supplying an initial drive current having an initial drive current value to the pump light emitting device during an initial drive current supply period, the initial drive current supply period being made up with a first period and a second period subsequent to the first period, the first period being shorter than the initial drive current supply period, the pump light emitting device emitting the pump light having initial light intensity upon receipt of the initial drive current;

(b) controlling the scanner to start scanning the laser beam after the first period has elapsed from a start of supplying the initial drive current in (a), and

(c) supplying a prescribed drive current having a prescribed drive current value to the pump light emitting device after the second period has elapsed from a start of scanning the laser beam in (b), the prescribed drive current value being smaller than the initial drive current value, the pump light emitting device emitting the pump light having prescribed light intensity upon receipt of the prescribed drive current, the laser beam emitting device emitting the laser beam having the prescribed beam intensity when the pump light having the prescribed light intensity is incident upon the laser beam emitting device.