What are the structural designs of TV LCD screens?

2022 06/16

Smart products are very popular now. Many manufacturers will enter this industry. Here, the editor will talk about TV LCD screen for you. Its structure mainly includes: liquid crystal display module, power supply module, drive module and key module. Usually, LCD module manufacturers have completed electromagnetic compatibility (EMC) testing before production. EMC is an inevitable and important issue in LCD TV design. If the EMC design is not good, it will lead to weak anti-interference ability, water ripple and stroboscopic problems in the process of TV broadcasting, and it will be impossible to watch in severe cases. The following is a brief description of the design of key EMC components:

1. LCD driver board design

The most important means to overcome electromagnetic interference is grounding. LCD module screen TV main driver board mainly includes: analog signal part, high-speed digital circuit part, noise source DC-DC power supply part. The grounding of the TV power supply part (DC-DC) of the stay LCD screen is mainly separated from the grounding of other parts such as decoding and main chip processing, so as to reduce the interference of the power supply grounding on the image display and TV sound. DC-DC Power and Ground: On a printed circuit board, the power and ground wires are the most important. Let the analog and digital circuits have their own power and ground paths, respectively.

2. Whole machine design

Use of protective cover: Generally, a shielding cover is required for the LCD module, the main control board and the power supply part. The main frequency of the main chip is the main cause of electromagnetic interference. The frequency harmonics of the main frequency are most likely to generate electromagnetic interference. In the electromagnetic compatibility experiment, the frequency of the main frequency and the position of the harmonic have great electromagnetic interference. In the design, some shielding measures should be added to the main chip. The main shielding measure is adding a metal shield to the digital board. Adding a shield is the most effective way to resist EMI.

3. Power Module Design

The LCD TV power supply part adopts switching power supply. The reasons for the electromagnetic interference of switching power supplies are very complex. The two main functions of the power supply section are to drive the backlight of the LCD screen and provide DC power for other modules (including the driver module and key module). The design of the power module directly affects the entire system. If the design is not good, it will cause the TV to generate large water waves, and in severe cases, the TV will fail. At the same time, it will seriously affect the normal use of other nearby devices.