Sinocrystal has already shared with you the material of FPC.
Here we would like to share the construction process of FPC with you. .
At first glance, typical flexible or rigid-flexible boards look pretty bland and uninspiring. However, getting them manufactured requires a few extra steps.
*Manufacture of any flex-rigid combination board starts with the manufacture of a single-sided or double-sided flexible board
*Manufacturing can start with a pre-pressed flex board, or it may start with a PI film
*Then laminate the original bare board with copper, or plated with copper skin
*The lamination process requires a thin layer of adhesive to be brushed on the film
*The adhesive-free process involves planting the "seeds" of copper plating on the film. This is usually done using a vapor deposition technique (e.g. sputtering) to seed the nodules for the subsequent chemical precipitation process
*The subsequent drilling, plating through and etching of single- or double-sided flexible boards is generally similar to the process for double-sided rigid boards.
The use of epoxy or acrylic adhesives, or sputter coating is the key to creating a thin copper coating.
Pressing the RA/ED copper foil layer onto the adhesive (this is the mainstream method) or using chemical plating methods.
The holes for vias and pads are usually mechanically drilled.
Multiple flexible boards can be drilled simultaneously by working turntables.
Using the same approach as rigid boards, pre-cutting of flexible boards can be implemented in conjunction with drilling, which requires more careful documentation, but alignment accuracy can be reduced.
Laser punching is typically used to handle ultra-small drill holes, which can add significantly to the cost, as each film needs to be drilled separately. Excimer (UV) or YAG (infrared) are used for high precision drilling (microvias), and CO2 lasers are used for medium sized holes (4 mils and up).
The use of stamping can handle large through holes and plate shears, but that is a separate processing step.
Once perforation is complete, copper is added to the holes using the same deposition and chemical plating method as for rigid boards.
The film surface is coated with a photo-sensitive resist, then exposed using the desired pattern, and the unwanted resist is removed before chemically etching the copper.
After the exposed copper skin is etched off, the resist is peeled off by chemical method.
The top and bottom of the flexible board are protected by a cut and shaped covering film. Sometimes there is a need to solder in some components on the flexible board, then the covering film plays the role of solder resist layer.
The most common cover film material is polyimide, which is bonded with adhesive, but here it is also possible to use a glue-free process.
In the adhesive-free process, the photo-sensitive solder resist is brushed onto the flexible board, which is the same process as for the rigid board. To reduce costs, screen printing can be used, followed by curing by UV irradiation.
One thing to note about the protective film is that it is usually placed on only a portion of the exposed flex circuit.
For rigid and flexible boards, the protective film is not placed on the rigid board unless there is a small overlap - usually about half a millimeter.
Of course the protective film can include the entire rigid section, but doing so would be detrimental to the rigid board's adhesion and z-axis stability.
This optional protective film is called a "bikini film" because it covers only the exposed portion.
In addition, the cover film in the components or connector pads to leave a cutout to retain at least two sides of the pad.
The final step in the manufacturing of flexible circuits is to cut. This is often referred to as "undercutting".
A high-volume, low-cost shearing method is to use a hydraulic press and a steel die. Although high-cost steel dies are required here, this method can cut out many flexible circuit boards at the same time.
For prototypes and small production runs generally use knife tooling. A very long blade is shaped to the contour of the flexible circuit board and then affixed to the base of the die (MDF, plywood or a thick plastic such as PTFE). By pressing the knife die, the flexible circuit is cut into shape.
For smaller output prototype manufacturing, you can use to X/Y cutter, somewhat similar to that used for vinyl signage.
If the flexible circuit board also has to be pressed with a rigid board to form a flexible and rigid board, which means that the flexible board and rigid board need to be pressed together. The same as the ordinary flexible board, it needs to be independently drilled, plated and etched. The difference is that it is thinner and more flexible due to the lack of glass fibers.
Less flexible boards can be manufactured with PI and glass fibers as required. Finally it has to be also pressed together with rigid board as a sandwich and made into a patchwork board.
Flexible circuit board is with rigid circuit board and other flexible board, hot pressed together by adhesive.
Each flexible board is not adjacent to each other.
In order to maintain flexibility, each flexible board has a maximum of 2 copper skin layer.
The flexible boards are separated from each other by rigid semi-cured sheets, substrates or PI core bonding sheets made of epoxy resin or and acrylate adhesives.
Essentially, each rigid sheet is cut separately in the part of the flexible sheet that is filled.
The flexible printed circuits have been embedded in the final assembly board, with the rigid board retained underneath the flexible circuits to support the flexible circuits. This helps keep the flex circuit flat during the soldering and assembly process.
If the flex circuit is not supported there are some potential hazards, such as flex circuit bending or large cracks during the soldering process, especially in reflow ovens.
Solder resist can be applied with a covering film similar to a pressure sticker or with the light sensitive solder resist coating mentioned earlier.
Finally, once the 6-layer board consisting of flexible and rigid board is pressed, the outermost (top and bottom) layers of copper foil are joined together. This is usually done by drilling holes from the top layer to the bottom layer and then coating. It is also possible to use a laser to drill blind holes (from the top layer to the flex or from the bottom layer to the flex), but this will increase the cost.
The final step is to print the top and bottom layers with solder resist, silkscreen and anti-corrosion plating (e.g., nickel dip) or solder homogeneous coating (HASL).
Finally, if you want to know more, please feel free to contact sinocrystal.
2021年1月9日下午,继台湾半导体制造有限公司之后的第二大合同晶圆制造商联电公司报告说,其在台湾的工厂发生爆炸。该工厂目前有一些8英寸晶圆生产线也可能受到影响。TFT-LCD,OLED,黑白屏,段码屏,触摸屏,工业级液晶屏
华之晶是一家源头显示器制造商,我们专注于定制液晶显示器。TFT-LCD,OLED,黑白屏,段码屏,触摸屏,工业级液晶屏
日本NEG的一家高槻液晶显示器(LCD)玻璃厂停电,可能会加剧已经很紧张的玻璃供应状况,导致玻璃全面短缺。TFT-LCD,OLED,黑白屏,段码屏,触摸屏,工业级液晶屏
在数字时代,LCD屏幕无处不在,从手机和平板电脑到电视和显示器。尽管LCD技术已经相当成熟,提供了成本效益高且性能稳定的显示解决方案,但在其生命周期中,用户可能会遇到各种显示问题。本文深入探讨LCD显示屏的常见不良现象,分析其原因,并提供针对性的解决方案,帮助用户和技术人员更好地理解和维护他们的设备。
在选择显示器时,面板类型是一个关键的考虑因素,因为它直接影响到显示效果和用户体验。目前市场上常见的三种面板类型是TN(Twisted Nematic)、IPS(In-Plane Switching)和VA(Vertical Alignment)。这些技术各有特点,适用于不同的使用场景和用户需求。
段码屏和点阵屏各有优势和不足,适用于不同的应用领域。了解这两种技术的基本工作原理和特点,对于在特定应用中选择合适的显示技术至关重要。随着科技的发展,我们可以期待这两种显示技术会继续演进,以更好地适应未来的需求。
COG (Chip-on-Glass) 是一种在玻璃基板上直接安装半导体芯片的技术,主要用于液晶显示器(LCD)和其他类型的显示屏。这种技术以其节省空间、提高效率和降低成本的优点而广泛应用。