Patent ID: 7630421

Claim:
A laser beam irradiation apparatus, comprising: laser beam oscillation means for generating a laser beam; first acousto-optic deflection means for deflecting the laser beam generated by said laser beam oscillation means, said first acousto-optic deflection means including a first acousto-optic device for deflecting the laser beam generated by said laser beam oscillation means, a first RF signal oscillator for applying a RF signal to said first acousto-optic device, first deflection angle adjustment means for adjusting the frequency of the RF signal to be outputted from said first RF oscillator, and first output adjustment means for adjusting the amplitude of the RF signal to be produced by said first RF oscillator; second acousto-optic deflection means for deflecting the laser beam generated by said laser beam oscillation means, said second acousto-optic deflection means including a second acousto-optic device for deflecting the laser beam generated by said laser beam oscillation means, a second RF signal oscillator for applying a RF signal to said second acousto-optic device, second deflection angle adjustment means for adjusting the frequency of the RF signal to be outputted from said second RF oscillator, and second output adjustment means for adjusting the amplitude of the RF signal to be produced by said second RF oscillator; control means for controlling said first and second deflection angle adjusting means and said first and second output adjusting means; a condenser for condensing the laser beam deflected by said first and second acousto-optic deflection means; and laser beam output detection means including a beam splitter disposed between said first and second acousto-optic devices and said condenser for splitting part of the laser beam deflected by said first and second acousto-optic devices and a light reception device for receiving the laser beam split by said beam splitter, said laser beam output detection means sending a light reception signal received by said light reception device to said control means; said control means determining an actual output power of the laser beam based on the light reception signal sent thereto from said laser beam output detection means in response to a control signal for controlling said first and second deflection angle adjustment means, arithmetically calculating a ratio of an actual output power when a first voltage is applied to said first reflection angle adjusting means of said first acousto-optic deflection means and a second voltage is applied to said second reflection angle adjusting means of said second acousto-optic deflection means, as compared to a maximum output power, determining a minimum ratio of the actual output power, arithmetically calculating a correction value based on the calculated ratio of the actual output power and the minimum ratio of the actual output power to produce a control map and controlling said first and second output adjusting means based on the control map.