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EVT develops the graphical programming Machine Vision Software for 1D, 2D, 3D, Themal Imaging and Hyperspectral solutions.

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Laser Inspection Laser Inspection

GWI System

POSTED 07/02/2013

rong>Glass Wafer Inspection System

The GWI System was build, to detect defects in glass wafers early in the production cycle. The system is based on a high resolution smart camera, which captures the image from the glass wafer. To meet the required accuracy in defect detection, a 5 MPixel sensor was selected. For higher requirements, sensors with higher resolutions are available.

Glass Wafer Inspection SystemThe complete System is build from a black aluminum structure, where the smart camera contains all the electronic. A high power LED light illuminates the wafer from the bottom side. Depending on the size of the inspected wafer, the diameter of the hole above the light is different.

The complete communication to the inspection unit can either be operated by Ethernet or RS232 interface. Optional communication via USB Interface.

The complete evaluation of the wafer is done in the smart camera. The cameras ARM Cortex A8 CPU with 1 GHz and an additional a 800 MHz DSP does the image processing. The picture of the glass wafer is taken and is processed immediately in the camera. The resulting data and images are transferred to the PLC. There is also an option to connect a display to the camera to see the results on the screen.

To run the evaluation process the Ethernet, RS232 and Power I/O connection is required. The power I/O contains also the RS232 interface. All other connections are for optional use.

After the programming the system is disconnected from the programming PC and the complete communication to the system is based on a communication protocol. For data communication the Ethernet or RS232 can be used. For the image transfer, the Ethernet connection is used.

The glass wafer inspection and defect detection is based on the remote protocol. These are simple strings, which are sent to the GWI (glass wafer inspection) camera and the answer about the result is also a string. So that the process can be controlled with a simple PLC if necessary.

The GWIP is for the analysis of glass wafer, which finds the defects on the surface from the glass wafer.

The program right now is optimized for the above described errors, but can easily adapted to other errors as long as they can be detected in the images. The actual system is based on a CMOS 5 Mpixel sensor, in the same housing you can get also a CCD sensor. With the CCD sensor are some other options available, which might be interesting to detect different errors to those we defined in this documentation.

The GWI System contains the Smart Camera, the Software and the cable set to connect the system with a main frame or a PLC. There are also some programs to visualize the results of the evaluation on a Windows based system.

And additionally there is an option, which makes it possible to connect the GWI directly to a VGA Monitor to display the actual status and the evaluation result.

The current software is based on the EyeVision 2.6R036LTS (Long Term Support). This version will be replaced with the next generation software EyeVision 3.0 with support for Asian language and many more features. With the next generation software the teach in is also possible on Linux systems.

Contact person:   
Klara Steinschneider
+49721 626905-82