Method of controlling the total energy amount of a plurality of laser pulses

Claim 1

A method for accurately controlling to a desired dose value D S the accumulated energy of a plurality of successive laser pulses in a laser beam each having an energy amount E, comprising the steps of: (a) measuring the sum of the energy amounts contained in a first succession of said laser pulses until the measured accumulated energy has reached a selected value which is a relatively high percentage of said desired dose value D S , (b) when the measured accumulated value has reached said selected value, attenuating the energy amount of said laser pulses to a fractional value of E, and (c) continuing to measure the sum of the energy amounts contained in said attenuated-energy pulses until the total measured accumulated energy reaches said desired dose value D S .

Claim 2

A method for accurately controlling to a desired dose value D S the accumulated energy of a plurality of successive laser pulses in a laser beam each having an energy amount E, comprising the steps of: (a) measuring the sum of the energy amounts contained in a first succession of said laser pulses until the measured accumulated energy has reached a selected value which is a relatively high percentage of said desired dose value D S , (b) when the measured accumulated value has reached said selected value, attenuating the energy amount of said laser pulses to a fractional value of E, and (c) continuing to measure the sum of the energy amounts contained in said attenuated-energy pulses until the total measured accumulated energy reaches said desired dose value D S .

Claim 3

An apparatus for accurately controlling to a desired dose value D S the accumulated energy of a plurality of successive laser pulses in a laser beam each having an energy amount E, comprising: (a) means for measuring the accumulated energy of a plurality of said successive laser pulses including means for generating a command signal indicating that the measured accumulated energy of a first succession of said laser pulses has reached a selected energy value which is a relatively high percentage of said desired dose value D S ; and (b) attenuator means arranged in aid laser beam and responsive to said command signal for reducing the energy amount of each laser pulse occurring thereafter to a fractional value of E and producing a second succession of laser pulses having an energy amount which is a fractional value of E which are measured until the measured accumulated energy reaches the desired dose value D s .

Claim 4

An apparatus for accurately controlling to a desired dose value D S the accumulated energy of a plurality of successive laser pulses in a laser beam each having an energy amount E, comprising: (a) means for measuring the accumulated energy of a plurality of said successive laser pulses including means for generating a command signal indicating that the measured accumulated energy of a first succession of said laser pulses has reached a selected energy value which is a relatively high percentage of said desired dose value D S ; and (b) attenuator means arranged in aid laser beam and responsive to said command signal for reducing the energy amount of each laser pulse occurring thereafter to a fractional value of E and producing a second succession of laser pulses having an energy amount which is a fractional value of E which are measured until the measured accumulated energy reaches the desired dose value D s .