LCD Projector Diagram

Ultra-high pressure mercury lamp

Ultra-high pressure mercury lamps offer superior illumination efficiency and duration. By setting the lamp operating pressure to over 200 atms, the light source radius is reduced, shortening the light arc and facilitating better optical design. Colors are also more easily rendered with the increased luminescence.

Integrator lens

This lens projects the whole screen brightly by converging and transmitting light evenly from the first lens array to the second lens array.

Polarization changer element

Though the lamp emits light waves with variety of orientations, high-temperature polysilicon (HTPS) liquid crystal displays transmit only longitudinal waves. Polarizer technology converts shear waves to longitudinal waves so that the light can penetrate through HTPS as much as possible. This technology improves brightness by about 1.5 times.

Dichroic mirror

Two dichroic mirrors divide the light from the lamp into red, green, and blue components. The base glass of these mirrors is coated with a thin film that reflects only light of a specific wavelength.

Dichroic prism

A dichroic prism divides light into red, green, and blue, to form three pictures from the corresponding colors sent by the LCD (HTPS) panels. Color and image are recomposed by reflecting red and blue light and transmitting green light. The prism itself is made by combining four triangular poles into one rectangular solid. High precision is required in the processing and adhesion of poles to avoid dark lines and double images caused by misaligned surfaces.

LCD panels

Most LCD panels used in projectors today are made of High Temperature Poly-Silicon (HTPS) which has an active matrix and is transmissive. HTPS panels are superior in that they are smaller, have higher resolution and higher contrast, and can embed drivers.

The main function of HTPS is to act as a light valve for projectors. HTPS has a thin-film transistor (TFT) generated by poly-silicon in each pixel. These pixel transistors act as a conduction switch by changing the scan line's voltage. HTPS LCD panels are produced in the same way as semiconductors. They are small and highly reliable because they can easily be miniaturized and drivers can be generated on substrates by processing at a high temperature.

Dust proof glass

Glass is affixed to the LCD panel to prevent damage to the TFT substrate and adhesion of dirt. Dust on the dust-proof glass isn't visible to the naked eye because it is out of the range of focus when projected.

Source: 3LCD.com, September 2007