Our Laboratories of Innovation in Adhesive Materials are in charge of developing adhesive-related products for the Oji Group.
Diagram of the Composition of a Smartphone/Tablet and Main Developed Products
The labs’ research themes are broad in scope, extending from general seals and labels to special adhesive products for industrial use and even highly functional products for optical and medical purposes. Specific examples include paper products such as thermal paper labels, film products like protective films for use in construction and decorative films for product forming, and optical double-sided adhesive film and hard coat films for use with smartphones and tablet computers.
Composition of a Smartphone/Tablet
1) For Cover Glass—High Retardation Anti-Scattering Film
Eliminates “Mura” (rainbow), Improves Visibility
Frequently used in car touch panel displays such as navigation systems and instrument panels. Driving with polarized sunglasses can cause an iridescent pattern (= “mura”) to appear on displays due to the difference in phase with the display, reducing visibility. Controlling the phase difference of the anti-scattering film makes it possible to inhibit such mura.
Oji is also developing other cover glass anti-scattering films with a variety of capabilities. Some examples of anti-scattering films being developed to meet customer needs include those which control the refractive index of light to reduce screen reflections, prevent scratches, reduce finger friction, and inhibit smudges.
2) For Affixing on the Back—Anti-Watermark Film
Prevents Adhesion to LC Module, Protects Image Quality
As touch panel modules have become lighter, thinner, and larger, they have become more prone to warping through simple finger operation. When the touch panel is pushed into and adheres to the LC module, it creates a visual defect known as a watermark, and the problem of watermark occurrence has grown more severe in recent years.
Oji’s Laboratories of Innovation in Adhesive Materials have developed an anti-watermark film which prevents such adhesion through the use of a special surface asperity (unevenness) design formed on the film, protecting the image quality of the LC module and resolving this problem.
3) For Affixing Components—Optical Double-Sided Adhesive Film
Combines the Conflicting Characteristics of High Pliability (ability to fill gaps) and High Durability
Our optical double-sided adhesive film is a highly transparent adhesive sheet used for affixing touch panel components, primarily for smartphones and tablets. With these sheets, we have sought to provide a variety of highly functional characteristics, including ITO anti-corrosion, a low dielectric constant, reworkability, gap filling, and durability. Seeing how well we could get a thin adhesive film to flexibly conform to the uneven surfaces of frame printing and circuits was particularly challenging.
In order to combine the conflicting characteristics of gap filling (pliability) and high durability (high cohesion), our Laboratories of Innovation in Adhesive Materials developed a dual cure adhesive film that is pliant when being applied but which hardens when later exposed to UV light.
In addition to the current thermosetting line, Oji has established a new dedicated UV curing line.
The new line will make it possible to eliminate the drying processes required on the thermosetting line, in turn enabling us to provide organic solvent-free products that pose a low environmental load. We are also working on developing other new products which incorporate the unique characteristics of UV curing.