The polarizer film is an element which transforms the natural light into linear polarizer. Circular polarizer is a film consists of a polarizer film and an 1/4 retardation film through an adhesive layer, and Circular polarizer type touch panel applies this circular polarizer technology.

When the phase waves of polarizer film and 1/4 retandation film are combined, the optical oscillator forms a shape of spiral. The spiral looks as concentric circle from the light traveling direction, and this state is called "circlular polarization".

When reflection occurs to incident polarizer light (anti-clockwise or clockwise), it will be reflected as inverse polarizer light. This reflection light will be absorbed by the polarizer film and will not pass through. By placing circular polarizer film on the top surface of a touch panel will eliminate the reflection light from inside the touch panel.

For circular polarizer type touch panel, an 1/4 retardation film is placed at the bottom side of touch panel to fulfill the condition of transparency of circular polarizer film in order to convert the outgoing light from LCD which is linear polarizer into circular polarizer.

At first, Film-Glass structure was common for low reflective touch panel. For Film-Glass structure, double-sided adhesive is used to bond LCD with touch panel. By fixing the outer frames using adhesive lead to the loss of transparency because of unavoidable air layer produced between the bottom side of touch panel and the top surface of LCD.

Film-Film structured touch panel which directly bond a low reflective touch panel onto LCD in order to eliminate the air layer appeared following Film-Glass structure.

Although the countermeasures for contamination of foreign substances and removal of air-bubble are neccessary, using Film-Film type structure makes it possible to reduce outside reflection up to about 4% and obtain display of high contrast.