Distance detector for focus control in laser beam machine
First Claim
1. A distance detector for use in a laser beam machine, said laser beam machine detecting a distance between a focal position of a laser beam and a workpiece by use of a capacitance, then irradiating a condensed laser beam on said workpiece for laser beam machining, while controlling said distance between said focal position and said workpiece, said distance detector comprises:
- a sensing electrode forming a capacitance relative to said workpiece;
an input signal generator generating a first alternating signal defining an input signal, said input signal being input into said sensing electrode;
a signal detector detecting a second alternating signal defining a detection signal, said detection signal being generated at said sensing electrode and having a value varied in accordance with said capacitance between said sensing electrode and said workpiece;
a computing unit receiving said input signal from said input signal generator and said detection signal from said signal detector, said computing unit extracting a component having a same frequency as a frequency of said input signal from said detection signal, thereby computing said extracted component to generate a distance information output representing said distance between said focal position and said workpiece.
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Accused Products
Abstract
A distance detector detects a distance between a focal position and a workpiece by use of a capacitance. A sensing electrode forms the capacitance relative to said workpiece. An input signal generator generates an alternating signal or an input signal that is input into the sensing electrode. A signal detector detects an alternating signal or a detection signal that is generated at the sensing electrode and that has a value varied in accordance with the capacitance. A computing unit receives the input signal from the input signal generator and the detection signal from the signal detector. The computing unit extracts a component having the same frequency as a frequency of the input signal from the detection signal. Thus, it computes the extracted component to generate a distance information output representing the distance between the focal position and the workpiece.
118 Citations
16 Claims
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1. A distance detector for use in a laser beam machine, said laser beam machine detecting a distance between a focal position of a laser beam and a workpiece by use of a capacitance, then irradiating a condensed laser beam on said workpiece for laser beam machining, while controlling said distance between said focal position and said workpiece, said distance detector comprises:
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a sensing electrode forming a capacitance relative to said workpiece; an input signal generator generating a first alternating signal defining an input signal, said input signal being input into said sensing electrode; a signal detector detecting a second alternating signal defining a detection signal, said detection signal being generated at said sensing electrode and having a value varied in accordance with said capacitance between said sensing electrode and said workpiece; a computing unit receiving said input signal from said input signal generator and said detection signal from said signal detector, said computing unit extracting a component having a same frequency as a frequency of said input signal from said detection signal, thereby computing said extracted component to generate a distance information output representing said distance between said focal position and said workpiece. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16)
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Specification