More and more electronic products on the market come with LCD screen display. When the product is detected, it is necessary to detect the display content of the LCD screen and the screen itself. The current solution generally uses the camera to capture the screen display image for analysis and comparison. Performing image analysis and comparison is a more complicated scheme. There are high requirements for the camera, light source, and the erection position and movement of the camera. The analysis requirements for the software are also very high.
Detection equipment embedded camera module has the following problems can not be solved:
1, the camera's requirements are high, and the other focal length, exposure, etc. need to be adjusted and fixed. If you want to adjust the focal length and exposure when you change the test of different products, you need to readjust the last product measurement, and you cannot change back to the original status. The corresponding test program or image template needs to be re-produced, this situation is not allowed in the production line, and such equipment is not versatile and may only test certain products.
2, high light source requirements, different screens may require different light sources, but also need to be uniform light, no reflection and so on. Another product should be in a dark box to avoid interference from outside light. Once the measured ambient light changes, the measurement will become unstable.
3. When the product screen is large or multiple products are to be tested at the same time, the camera must be able to move and adjust the shooting position. This requires an XY (Z) axis motion system, which is very costly.
4. The software analyzes the image is more complicated. To establish a template, each time the image is compared with the template. More content. If some of the comparisons require high accuracy, false positives will be higher. For example: the number of LCD screens on the lack of planning problems, missing places may have a blot display, and the larger the shooting angle is more obvious, to check out this problem, you need to shrink the specification range is very narrow, as wrongly measured Very high, production is not allowed.
Any one of the above problems is not handled well, and the equipment system is not acceptable.
Product testing is divided into two processes: semi-finished product testing and finished product testing. If the product is equipped with an LCD, the finished product inspection must be to detect the quality of the screen, and the finished product does not have too many interfaces. It must be the camera system. There are many semi-finished products that do not have an LCD but are assembled at the back. For this kind of semi-finished product detection, there are two solutions to detect the on-screen display content: one is to connect the LCD interface lead out to the LCD screen, and use the above-mentioned camera system to detect the on-screen display content. Another solution is to use the LCD screen driver signal decoding module developed by Kanebo to connect the LCD interface to the LCD screen driver signal decoding module to automatically decode the content to be displayed, thus avoiding the inconvenience of using the camera system. Stable and reliable.
Jin Kaibo automated test successfully used the segment code type LCD screen driving signal decoding module in the remote control test system provided by Qingdao Haier. This test system mainly detects semi-finished remote control products (as long as the IC and the SMD components are on the PCB, and the plugs required for other tests must be connected under the probes of the tool). The test contents include: key control, on-screen display content, infrared code generation and static Current detection and so on. The main hardware of this system is: relay matrix, segment code type LCD screen drive signal decoding module, infrared decoding module, current and voltage detection module and acquisition card. Among them, the segment code type LCD screen driving signal decoding module is independently developed by Jin Kaibo, and there is no similar product on the market at present.
The segment code type LCD screen driving signal decoding module has the following characteristics:
1, automatic learning function. Can learn the number of LCD COM lines, refresh order, frequency and operating voltage.
2. It can be manually set: working voltage, COM cycle, etc., SEG segments that need to be detected.
3. The number of COM currently supported is 4, and the number of SEG is 32. Can be expanded according to user needs.
4. If the product signal is abnormal, an abnormal code may be classified and reported, for example, the code of the missing segment will report the segment data error.
5. The LCD cable connected to the decoding module of the product reaches more than 1 metre. The decoding module is still stable, accurate, and reliable.
6, use the serial port to communicate with the computer, use 38400 baud rate, stable and fast.
7. The upper and lower sides of the PCB are brushed with insulating paint. Most of the lines are in the middle layer. The interference of dust and external noise is well shielded.
8. Any clutter or abnormality on any signal line can be detected, which covers the error type of the product.
In addition, if the LCD screen used by the customer is a dot matrix, the corresponding decoding module can also be developed according to the user's needs.
The use of electrical signals to decode the on-screen contents of the LCD is obviously superior to the use of the camera system: different products can be used on one device. Equipment movement and other factors do not affect the use of the device. Universality and stability are excellent. Different products need only to be replaced. Different tooling and program scripts greatly facilitate production.
If you have similar testing needs, give it away!