Circuit location sensor for component placement apparatus

A method for use in a component placement apparatus for determining the location of at least one circuit element with first and second edge portions on a circuit board, the component placement apparatus including processing means as a robot arm for placing components on the circuit board, said method comprising the steps of:

• illuminating the circuit board with light produced by a light source in sensing means attached to the robot arm;
• sensing the light reflected from the circuit board with an optical reflective light sensor in the sensing means, the optical reflective light sensor producing an output signal having a magnitude proportional to the light reflected form the illuminated circuit board;
• stepping the optical reflective light sensor across said at least one circuit element;
• processing the output signal of the optical reflective light sensor for each step for detecting the location of said at least one circuit element.

A method of operating component placement apparatus including processing means and a robot arm for placing components on a circuit board having at least one circuit element thereon with first and second edge portions, said method comprising the steps of:

• (a) loading a component placement program into said processing means;
• (b) determining the location of said at least one circuit element by the steps of:
• (i) illuminating the circuit board with light produced by a light source in sensing means attached to the robot arm;
• (ii) sensing the light reflected from the circuit board with an optical reflective light sensor in the sensing means, the optical reflective light sensor producing an output signal having a magnitude proportional to the light reflected from the illuminated circuit board;
• (iii) stepping the optical reflective light sensor across said at least one circuit element;
• (iv) processing the output signal of the optical reflective light sensor for each step for detecting the location of said at least one circuit element;
• (c) modifying the component placement program using the location determined for said at least one circuit element;
• and
• (d) executing the modified component placement program.

Component placement apparatus including processing means and a robot arm for placing components on a circuit board having at least one circuit element thereon with first and second edge portions, the processing means producing a control signal for positioning the robot arm and producing a strobe signal when the robot arm is positioned, said component placement apparatus further comprising:

• sensing means attached to the robot arm and including a light source producing light for illuminating the circuit board and an optical reflective light sensor for producing an output signal having a magnitude proportional to the light reflected from the illuminated circuit board;
• and
• converting means coupled to said sensing means for converting said output signal to a digitized signal in response to the strobe signal;
• and
• said processing means coupled to the robot arm for producing the control signal to step said sensing means across said at least one circuit element at least two times along the same path and coupled to the converting means for processing the digitized signal produced at each step for detecting the location of said at least one circuit element on the circuit board.

Component placement apparatus including processing means and a robot arm for placing components on a circuit board having at least one circuit element thereon with first and second edge portions, the processing means producing a control signal for positioning the robot arm and producing a strobe signal when the robot arm is positioned, said component placement apparatus further comprising:

• sensing means attached to the robot arm and including a light source producing light for illuminating the circuit board and an optical reflective light sensor for producing an output signal having a magnitude proportional to the light reflected from the illuminated circuit board;
• and
• converting means coupled to said sensing means for converting said output signal to a digitized signal in response to the strobe signal;
• and
• said processing means coupled to the robot arm for producing the control signal to step said sensing means across said at least one circuit element and coupled to the converting means for processing the digitized signal produced at each step for detecting the location of the first and second edge portions of said at least one circuit element on the circuit board.