Glue thickness inspection (GTI)

Patent metadata

Field	Value
Publication number	US-9593939-B1
Application number	US-201414584951-A
Country	US
Kind code	B1
Filing date	Dec 29, 2014
Priority date	Dec 30, 2013
Publication date	Mar 14, 2017
Grant date	Mar 14, 2017

Abstract

A glue thickness inspection system automates a thickness measurement functionality for determining the thickness of both non-transparent and transparent materials including, but not limited to, glue, gel, solder and epoxy. The glue thickness inspection system includes a laser detector, a movable platform for positioning a unit under test, and a controller for controlling movement of the platform, angle of the laser detector, and calculation of the transparent material thickness. The laser detector includes a laser for emitting a laser light onto the unit under test and a sensor for receiving corresponding reflected light. The sensed data is used by the controller to determine the transparent material thickness.

First claim

What is claimed is:

1. A material inspection system comprising:
a. a unit under inspection comprising a substrate and a transparent material, wherein the substrate comprises a surface, the transparent material is coupled to a first portion of the surface and a second portion of the surface is exposed;
b. a laser detector comprising a laser light source and a sensor, wherein the laser detector is positioned relative to the unit under inspection such that a laser light output from the laser light source impinges a sample point on the unit under inspection and the laser light has a non-vertical incident angle relative to the surface of the substrate, further wherein the sensor is configured to receive a mirror reflected light corresponding to the laser light;
c. a controller configured to receive data from the sensor corresponding to the received mirror reflected light and to determine a distance measurement corresponding to the sample point; and
d. a movement and alignment apparatus coupled to the unit under inspection and the laser detector, wherein the movement and alignment apparatus is configured to provide relative movement of the laser detector and the movement and alignment apparatus so as to determine the distance measurement at multiple sample points, at least one sample point on the second portion of the substrate and at least one sample point on the transparent material,
wherein the controller is further configured to determine a thickness of the transparent material according to the determined distance measurements.

2. The material inspection system of claim 1 wherein the movement and alignment apparatus is further coupled to the controller, wherein the controller is further configured to automatically control the movement and alignment apparatus to properly align the unit under inspection and the laser detector at the multiple sample points.

3. The material inspection system of claim 1 wherein the distance measurement corresponds to the distance traveled by the laser light from the laser light source to the sample point on the unit under inspection and to the sensor.

4. The material inspection system of claim 1 wherein the movement and alignment apparatus comprises an X-Y gantry.

5. The material inspection system of claim 1 wherein the unit under inspection comprises a printed circuit board assembly.

6. The material inspection system of claim 1 wherein the transparent material comprises one of a glue, an epoxy, a gel or a solder.

7. The material inspection system of claim 1 wherein the controller is configured to determine the thickness of the transparent material by subtracting the distance measurement determined at the sample point on the second portion of the substrate from the distance measurement determined at the sample point on the transparent material.

8. A material inspection system comprising:
a. a unit under inspection comprising a substrate, a transparent material and a non-transparent material, wherein the substrate comprises a surface, the transparent material is coupled to a first portion of the surface and the non-transparent material is coupled to a second portion of the surface;
b. a laser detector comprising a laser light source and a sensor, wherein the laser detector is positioned relative to the unit under inspection such that a laser light output from the laser light source impinges a sample point on the unit under inspection;
c. a controller configured to receive data from the sensor corresponding to the received mirror reflected light and to determine a distance measurement corresponding to the sample point; and
d. a movement and alignment apparatus coupled to the unit under inspection and the laser detector, wherein the movement and alignment apparatus is configured to provide relative movement of the laser detector and the movement and alignment apparatus so as to determine the distance measurement at multiple sample points, at least one sample point on the transparent material and at least one sample point on the non-transparent material, further wherein the movement and alignment apparatus is configured to rotate the laser detector between a first position when the sample point is on the transparent material such that the laser light has a non-vertical incident angle relative to the surface of the substrate and the sensor is configured to receive a mirror reflected light corresponding to the laser light, and a second position when the sample point is on the non-transparent material such that the laser light vertically impinges the sample point and the sensor is configured to receive a diffuse reflected light corresponding to the laser light, wherein the controller is further configured to determine a thickness of the transparent material and the non-transparent material according to the determined distance measurements.

9. The material inspection system of claim 8 wherein the movement and alignment apparatus is further coupled to the controller, wherein the controller is further configured to automatically control the movement and alignment apparatus to properly align the unit under inspection and the laser detector at the multiple sample points and to properly rotate the laser detector to the first position or the second position.

10. The material inspection system of claim 8 wherein the distance measurement corresponds to the distance traveled by the laser light from the laser light source to the sample point on the unit under inspection and to the sensor.

11. The material inspection system of claim 8 wherein the movement and alignment apparatus comprises an X-Y gantry.

12. The material inspection system of claim 8 wherein the unit under inspection comprises a printed circuit board assembly.

13. The material inspection system of claim 8 wherein the transparent material comprises one of a transparent glue, epoxy, gel or solder.

14. The material inspection system of claim 8 wherein the non-transparent material comprises one of a non-transparent glue, epoxy, gel or solder.

Assignees

• Flextronics Ap Llc

Inventors

• Xie Hongqiang
• Zhao An Qi
• Zhang Jiyang
• Feng Zhen
• Geiger David

Classifications

• G01B11/06

  for measuring thickness {; e.g. of sheet material (thickness measurement by thermal means G01B21/085)} · CPC title

• G01B17/025

  for measuring thickness of coating · CPC title

• H05K1/0266

  Marks, test patterns or identification means · CPC title

• H05K1/00

  Printed circuits · CPC title

• G01B11/0625 Primary

  with measurement of absorption or reflection · CPC title