solder lcd display manufacturer

Our new line of 10.1” TFT displays with IPS technology are now available! These 10.1” IPS displays offer three interface options to choose from including RGB, LVDS, and HDMI interface, each with two touchscreen options as capacitive or without a touchscreen.

The new line of 3.5” TFT displays with IPS technology is now available! Three touchscreen options are available: capacitive, resistive, or without a touchscreen.

PIN connection is the most widely used connection because it is very steady. Unfortunately, not everyone is an expert at soldering. Every now and then, we can hear customers complaining about the high failure rate after the PINs were soldered on PCB. And I was always wondering if they did the soldering properly. More often than not, it’s the soldering problem. It’s not the quality problem of LCD screen itself. We feel it is our obligation to do some tests to help those who lack experience.

In order to test the impact of the soldering temperature, we deliberately made it 350 degrees Celsius far higher than the normal. The soldering iron head was placed at the distance of 4.0 mm from bottom of LCD screen.

It only took about 4.0 seconds to melt the glue before it bubbled. It would cool down in a few seconds after the soldering iron head was removed and then it solidified slowly and shrank when it was completely cooled.

One interesting idea was that we located the PIN which was responsible for the missing segments of LCD screen and re-soldered it with overheated temperature. Pulled the PIN down a little, which would make it temperately connect in normal again. We could see it displaying the whole diagram for a while. When we were glad that we fixed the LCD screen, the old problem repeated again. It was easy to understand because the overheated temperature damaged the glue and turned the chemical composition into something else. Now the LCD screen was completely damaged and was unrepairable.

Let us try another experiment. We soldered the perfectly normal LCD screen with overheated temperature. It was as sure as the sun comes from the east that the old missing segment problem recurred. I am going to remind everyone here don’t ever solder the PINs with overheated temperature because it will definitely cause the missing segment problem.

Let us hit the PINs with overheated temperature while we don’t use the UV glue to fasten the positions of the PINs. Wait. Is it possible not to use UV glue? Of course, it isn’t. It is never able to fasten the PINs without UV glue. This was just an experiment to explain what would happen in a hypothetical situation. Now we continued the experiment. We put a 350 degree Celsius soldering iron head directly on PIN for 10 seconds and more until the polarizer turned yellow. To our surprise, the LCD screen was working perfectly fine. Now we could conclude that it was UV glue which was overheated that caused the missing segments and other problems. But we can’t make a LCD screen without it.

1. The distance from the soldering iron head to the bottom of LCD screen should be at least 4.0 mm and the temperature should be below 260 degrees Celsius. The time should be less than 4 seconds for the soldering iron head on PINs to avoid making the glue bubble.

2. The soldering iron head should contact two adjacent PINs at the same time and make the heat transfer more evenly. It should form 30 degree angle with PINs because this will make contacting area larger and heat transfer faster. It will be a perfect heating condition if we can make the two adjacent PINs reach the same temperature at the same time.

3. It is forbidden to let the PINs bear any pressure while we are welding the PINs. In order to prevent the displacing of the PINs because of the pressure from outside, it is best if we lay the front surface of LCD screen flat on a table.

The benefit of this kind of construction is low cost — there is no connector involved at all, just the flex soldered directly down to the PCB. The drawback is that the machine used in the LCD manufacturing process to connect them is expensive, and they are near impossible to re-work.

It is possible to hand solder the tail to the PCB. Great care must be taken since the conductors of the tail are completely exposed in the area where they are soldered.

Another approach uses ACF (Anisotropic Conductive Film) combined with heat and pressure to make the electrical connection between the flexible tail and the PCB. This two-step process still uses heat, but the temperature involved is much less than soldering.

For development work, we have found that the SchmartBoards company makes a number of breakout boards in a number of pitches that work with our displays.

For any questions about TAB, COB, COF, COG, hot bar soldering, or what LCD module is best for your product, please contact our knowledgeable and friendly support staff via email, phone, or chat.

Assuming the LCD is not going face down into the wave, wave soldering should not be a problem for this type of component. Make sure the wave system provides the correct preheat to the assembly prior to soldering and that you profile the assembly so that it meets the thermal characteristics of the component without exceeding them.

Ed Zamborsky is a Regional Sales & Technical Support Manager for Thermaltronics, located in New York. His position requires frequent customer visits throughout North America and the Caribbean and his position encompasses not only sales but the role of trainer and master applications engineer for all of Thermaltronics products. His expertise includes such specialties as hand soldering, convection and conduction reflow techniques, array rework, fluid dispensing equipment, and fume extraction. Ed has authored many articles and has presented many papers on topics such as; Low Volume SMT Assembly, Solder Fume Extraction, SMT Rework, BGA Rework, Lead-Free Hand Soldering, High Thermal Demand Hand Soldering, Lead Free Visual Inspection and Lead Free Array Rework.

Many of our customers wave solder LCD displays on their circuit boards without any problems of thermal damage. All of the devices I have seen are rated for wave soldering but the biggest concern I would have is over preheating. Typical topside board temperature as the board leaves the preheat is 210-220 F and I would avoid using topside preheat.

Depending on flux type, lead layout, orientation and lead length bridging could be a issue. If the leads are all inline keep them parallel to the conveyor. If you keep the preheat temperature in spec and dwell time in the wave to the minimum needed for good hole fill you should not have any issues with thermal damage to the LCD display.

Greg joined Electrovert in February 1984. Based out of the Electrovert applications laboratory in Camdenton Missouri, Greg has been in the process applications support role since 2000. His primary responsibilities include providing process and machine applications support for the wave soldering lines as well as process, machine and operations training. He also provides applications support for the reflow and cleaner lines. Greg is a PBET certified trainer and holds two patents on wave solder nozzle design.

There is another option other than wave solder. EFD developed a system that dispenses solder then uses a laser to heat the solder at the joint for reflow. This is much slower than wave solder, but should improve your quality and have even less thermal impact than hand soldering.

I would think selective wave soldering systems or selective soldering stations would be able to handle this application quite well. Spacers could be used to keep the LCD off the board and the board could be process through the equipment. Since this is a double sided board, I would not believe you would need too much top side preheat to get the solder to flow to the top side of the board, so this would be helpful in preventing the component from overheating during the soldering operation.

If you are currently manually soldering these components, you are applying more heat to each lead than they will see going over any wave solder system. Hence the heat from the wave or mass soldering system will be less than the heat from the solder iron, which should also help in improving the quality of the product. I say this because soldering irons are typically set at 650 to 750 F while soldering systems are typically set at 500F, quite a different.

Manufacturer of optical coatings, flat panel/LCD glass, instrument glass, & CRT filter glass. Products include anti-reflective/anti-glare coatings, transparent conductive coatings, fiber optic coatings, beam splitters, cover glass, etched glass, heater glass, glass sandwiches, lighting wedges, & circular polarizers. Applications include EMI/RFI protection, contrast adjustment, & optical instruments. Capabilities include precision glass cutting to tolerances of plus/minus .005 in. & precision glass edging to tolerances of plus/minus .002 in. Additional capabilities include custom manufacturing of laminated products. Services & products meet Military Spec.