Structure design of TFT LCD liquid crystal display module

The role of TFT LCD LCD module structure is to provide display light source, fix the TFT LCD and connect the motherboard interface to avoid direct contact between the circuit substrate and the edge of the LCD and external objects.The basis of TFT LCD LCD module design is structure design. In the following, we briefly introduce the structure design of TFT LCD liquid crystal display module.

The main components of TFT LCD liquid crystal display module are TFT display, flexible circuit board, and backlight. The work of structure design is mainly to evaluate the shape structure and assembly structure of these main components and whether they can achieve the customer’s requirements for product specifications. The LCD structure design is divided into two main steps: basic parameter specification evaluation and form factor evaluation.

TFT LCD liquid crystal display module structure composition

1. Evaluation of basic parameters and specifications
Need to confirm the developed LCD product specifications outline, the main items include display area size, resolution, module form factor (front frame) size, backlight brightness, etc. Display area evaluation, the size of the display area to the CF glass profile is often limited by the metal wiring design on the TFT glass. PCB and COF evaluation, the required area of the PCB substrate is projected based on information such as circuit diagram, number of components, and layout of circuit function modules. Based on the resolution, the specifications of the circuit system, the COF profile is roughly determined by referring to the COF manual. Backlight brightness evaluation, according to the brightness specifications of the developed LCD product, the transmittance of the structured display, the required brightness of the backlight can be calculated. The brightness of the backlight is equal to the module brightness divided by the transmittance of the display. According to the brightness requirement of the backlight source and the shape requirement of the module, it is decided whether to use a high-brightness, high-thickness direct-down backlight source or a low-brightness, thin side-light backlight source. In addition, the basic structure to support and fix the display and backlight, such as the front frame, adhesive frame, back panel, etc., should be evaluated, which is usually provided by the backlight manufacturer.

2. the shape and size structure evaluation
At this stage, it is necessary to integrate the evaluation results of the display, backlight, front frame, adhesive frame, back panel, FCB substrate and COF to clarify the overall shape of the LCD module and further evaluate whether the overall shape scheme meets the specification outline of the developed LCD product. The evaluation of the display shape generally requires the center of the display area and the center of the module to be consistent, allowing deviations of up, down, left and right within 3mm. The evaluation of the backlight requires the center of the backlight’s light-emitting area and the center of the display area to be consistent.The form factor evaluation of the FCB substrate and COF is mainly to evaluate the PCB substrate and COF crimping position and crimping method. Specifically, it is to evaluate the configuration method that the substrate can be actually assembled, such as whether it is an L-shaped bend, or a U-shaped bend. Combined with the configuration of the PCB substrate, determine the length and location of the COF. The final determination is whether the substrate and COF can be completely contained within the module profile after the actual crimping.

The structure design of TFT LCD liquid crystal display module should be designed to achieve reliability of process, material and assembly in functional design as well as safety, beauty and environmental protection in quality design, so as to improve the cost performance of LCD products. In response to the increasing market demand for LCD product quality, we seek the best structural design solutions to provide customers with high quality TFT LCD liquid crystal display products.

Date:2022-8-18 Author:Ewv LCD

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