Optical Clear Film, OCF
OCF(Optical Clear Film) is a new type of optically transparent adhesive, which is specially used to supplement or replace the current optical adhesive films of OCA and LOCA, and is suitable for TP/LCM optical bonding.
It has excellent adhesion to glass materials, and the bonding process is similar to that of OCA. However, after bonding, it required light or heat treatment to obtain better compensation for segment differences and adhesion ability.
OCF Bonding Structure and Process
As shown in Figure 1, OCF is generally used for bonding of cover glass and ITO glass or bonding touch panel and LCD. The light transmittance of OCF is above 96%, and it is non-corrosive to ITO film.
First, make sure that there is no dust, fingerprints, or other impurities on the surface of the touch screen and LCD. Use a dedicated rolling device to bond the OCF to the display or touch panel, ensuring there are no bubbles or wrinkles. Then place the pre-bonded components in a vacuum degassing device, and finally heat at 60-80 degrees and UV cure.
Advantages and application of OCF
Advantages
1. The light transmittance of OCF is above 96%, and it is non-corrosive to ITO film.
2. OCF has the function of the explosion-proof film, and its tensile strength is far better than OCA. It is not necessary to apply explosion-proof film to the screen.
3. It has strong compensation ability and is easy to adjust. The film thickness is 100um~200μm, easy to handle and cut.
4. Using OCF film to bond the touch screen is simple, the process is short compared to OCA, the operation is simple, and can be achieved in large-scale continuous production.
5. The yield rate of using OCF is greater than 95%, and defective products can be reworked on-site before curing. The main material has no loss, which can greatly reduce the production cost.
6. OCF combines the advantages of OCA and OCR: no overflow and strong ability to compensate for the segment differences, and can accurately control the thickness between layers, but its adhesion ability is slightly insufficient.
7. OCF is a thermoplastic elastomer, which has flow properties when heated and can fill the ink layer. When it returns to room temperature, it forms a stable filling shape and will not rebound due to stress, as shown in Figure 3.
Application
For uneven surfaces, the excellent thermoelectricity of OCF can fill the depressions, so OCF can be used for transparent optical components and touch modules of various types and sizes.
Using OCF can effectively solve the problem of optical bonding of larger-sized TPLCM, and the color presentation and clarity of the product far exceed that of traditional double-sided tape (air bonding).
It applies to a wide range of product specifications and sizes and is not subject to size limits. It is suitable for large and small screens of various products from watches to color TVs.
OCA vs. OCR vs. OCF
Many indicators of OCF are better than OCA. The products produced by OCF have reached and exceeded the indicators of products using OCA adhesive, which solves the major problem of high defective rate of finished products for customers and increases the strength of the panel several times. Many factors have led to a significant reduction in production costs. The following compares the three lamination processes of OCA, OCR, and OCF.
| Compare item | OCA | OCR (LOCA) | OCF |
| Interval control | Depends on OCA thickness and accuracy | hard to control | Can be precisely controlled |
| Glue overflow | No | Yes | No |
| Adhesion | Weaker | Stronger | Generally |
| Repair step difference | There are bubbles | Diffcult to produce bubbles for point touch | Ability better than OCA |
| Segmental Absorption | Generally | Good | Better |
| Efficiency | Generally | Generally | The same equipment can be used for batch and continuous production |
| Bonded product yield | The one-time yield is over than 90% and can be repaired | The first-time yield is less than 90%, making it difficult to repair | The one-time yield is over than 95% and can be repaired |
| Equipment investment | Generally | Higher | Generally |
| Material requirements | No special requirements | Hard to hard material fit | No special requirements |
| Application | Small size product | Small and medium size products | Various sizes of product; currently common used in large size product |
Tailorpixels has years of experience in display structure and production and can evaluate the best solution according to your project.
More to learn about related topics:
What is OCA Bonding Technology?
