First, What is OCA?
OCA (Optically Clear Adhesive) optical adhesive is one of the raw materials of touch screen. It is made of double-sided adhesive tape by making optical acrylic pressure-sensitive adhesive into a substrate-free adhesive layer and then applying an optical release film on the upper and lower bottom layers. Double-sided adhesive tape without base material, has the advantages of high cleanliness, high light transmittance, low haze, high adhesion, no crystal point, no bubble, water resistance, high temperature resistance, ultraviolet resistance, etc., and its thickness It has high uniformity and is close to the refractive index of glass, PC and PMMA. It will not cause yellowing, aging, fogging, detachment from the surface to be adhered and bubbles.
Second, the difference between good and poor quality OCA :
A good quality OCA can achieve the following effects:
1. It can reduce glare, reduce the loss of light from LCD or AMOLED display, increase the brightness of display and provide high transmittance and reduce energy consumption;
2. Increase the contrast, especially the contrast under strong light; the surface connection has higher strength;
3. Avoid Newton's rings;
4. The surface of the product is smoother and free of wrinkles, bubbles and impurities, and the displayed image has almost no effect through the OCA optical glue.
5. No boundary, expand the visible area; good defoaming effect, high TP yield, no yellowing, good rework advantages.
The poor quality OCA mainly has the following problems:
1. The process of sticking glue is prone to dead bubbles and cannot be defoamed.
2. After sticking the glue and removing the bubble, it will easily cause the bubble to rebound. Rework is required, which costs labor and costs.
3. It is easy to produce yellowing after using the glue for a period of time.
4. The protective film on the uncovering glue will produce an impression. There will be residual greasy rubber and asymmetry around.
Pay attention to the following points when purchasing OCA dry glue:
Focus on checking for indentations (materials are not allowed to have joints), creases, white spots, foreign objects, pinholes, depressions, bubbles, and wrinkles.
Third, OCA use in Phone LCDs full lamination technology