5.4 Properties and applications of cellulose triacetate film

Abstract

The CTA film can be characterized by e.g. its relatively high moisture regain, significantly low birefringence, and moderate mechanical strength. Having been commercialized more than fifty years ago, it has been widely used as photographic film, protective film for polarizing plate, and optical compensation film for liquid crystal display (LCD). The photographic film application exploits the optical isotropy and unique physical properties of the CTA film. In the application of the CTA film to protective film for polarizing plate, its low in‐plane birefringence is of particular importance. In the optical compensation to enhance the viewing angle of LCD, the CTA film, because of its moderate retardation in thickness direction (Rth), serves as an element of compensator as well as a base film. Considering the growth of the LCD market, the demand for CTA film is believed to be further expanding.

Competitive Solvation and Chemisorption in Silver Colloidal Suspensions

“…This film is stretched and doped with iodine or organic dyes to provide the polarizing function. The polyvinylalcohol polarizing layer is usually protected against mechanical and other environmental effects by two cellulose triacetate films with highest optical properties and very low birefringence, see Figure 15 [5]. Each LC display needs two polarizers by virtue of the physical principles governing the electro-optical effect of the liquid crystals.…”

56-3:Distinguished Paper: A Novel Moth-Eye-like Surface Film that is Anti-Reflective and Highly Scratch Resistant

“…A polarizer in an LCD consists of a stretched, iodide-doped polyvinyl alcohol (PVA) film and two protection films which sandwich the PVA film. Cellulose triacetate (TAC) film is most commonly used as protection film because of its superior characteristics such as high transparency, smoothness, optical isotropy (low birefringence), flexibility, and ease of handling [1] [2]. The protection film on the front side usually has an anti-glare (AG) layer on the TAC film for better visibility and scratch resistance.…”

Compensation and control of the birefringence of polymers for photonics

“…[1][2][3] Recently, a great deal of research has been conducted on the reduction of birefringence in optical polymer films for LCDs. 4 The research can be classified roughly into two categories. The first is based on approaches involving polymer processing, [5][6] and the second is based on approaches involving the chemical design of polymers that exhibit a low birefringence.…”

“…The aim of the former approach is to inhibit the orientation of polymer chains by adjusting the processing conditions, for example, by increasing the molding temperature and extending the annealing time for injection molding or by adopting processing methods such as a solvent casting. 4 In the solvent-casting method, the polymer is dissolved in an organic solvent and the resulting solution is spread onto a flat and smooth substrate. Low-birefringence polymer films can be obtained by removing the organic solvent in a drying process.…”