Some Tips on FPC of the LCD Module


The design

1. Line: Because the FPC will expand due to temperature and pressure during the ACF crimping, the expansion rate of the crimp finger must be taken into account in the initial design of the line to perform pre-compensation processing;

2. Typesetting: The design products are symmetrically distributed in the entire layout as much as possible. The minimum interval between each two PCS products is maintained at more than 2mm. The non-copper portion and the via-dense portion are staggered as much as possible. Both of the two parts are two important aspects that caused the material to shrink in the subsequent manufacturing process.

3. Selection of materials: The plastic film of the cover film should not be thinner than the thickness of the copper foil so as to avoid deformation of the product due to insufficient filling of the glue during lamination. The thickness and uniformity of the glue are even the greatest culprit in the expansion and shrinkage of the FPC material.

4. Process design: The cover film covers all copper foil parts as much as possible, and it is not recommended to stick the cover film, to avoid uneven force during pressing, and it is not advisable to use a 5 mil or more PI-reinforced laminated glue. If it cannot be avoided, only after the cover film is pressed and baked, can it be pressed with PI to reinforce.

The material storage

It needs to be stored strictly according to the conditions provided by the material supplier. The refrigerated product should be refrigerated without sloppy handling.

 

Manufacturing

1. Drilling: It is advisable to add baking before drilling to reduce the expansion and shrinkage of the substrate during subsequent processing due to the high moisture content in the substrate.

2. Plating: Should be made with short-edge plywood, which can reduce the distortion caused by the water stress caused by the swing. Reduce the swinging degree when electroplating, minimize the number of plywood and asymmetrical plywood can be assisted with  other side materials; When electroplating, the lower groove is charged to avoid sudden high current impact on the plate, so as to avoid adverse effects on plate plating.

3. Compression: The expansion and shrinkage of traditional presses are smaller than quick presses. The traditional presses are thermostatically solidified, but the quick presses are heat-cured, so the traditional press in control glue is more stabilized, and of course the layout of laminate is a very important part.

4. Baking: Baking is a very important part of fast-pressing products. Baking conditions must reach to the extent that the glue is completely cured, otherwise, there will be endless problems in the subsequent production or use. The baking temperature is first gradually warmed up to the temperature at which the glue completely melts, and continues to this temperature until the glue is completely solidified, and then gradually cools down.

5. To maintain the stability of temperature and humidity in all stations during the production process, the transfer between stations, especially for outbound production, and the conditions for product storage must be paid special attention to.

 

Packaging

Of course, the completion of the product does not mean that everything is going well. It is necessary to ensure that customers do not have any problems in the subsequent use. In terms of packaging, it is best to bake first to dry the moisture absorbed by the substrate during the manufacturing process, then use vacuum packaging and guide customers how to save.

 

Therefore, to ensure the stable quality, from the material preservation → all process control → packaging → before the use of customers, it must be strictly in accordance with specific requirements to implement.

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