[DNP double-layer rear-projection screen technology and optical principle talks] Engineering projection screen technology introduction

1. Definition of optical screen

A screen containing one or more optical lens systems is called an optical screen. In the lens, the light is refracted and the direction is changed. Only the rear projection screen can control the direction of the light, so only the rear projection screen is an optical screen ; The direction of the light depends on: the refractive index of the screen material and the cross-sectional shape of the lens. 2. Optical Fresnel lens

　 The difference between a traditional lens and a Fresnel lens is shown in the figure below:

In the Fresnel lens, only the curved surface is the effective part of the lens. If you remove the other parts and flatten the effective lens part (as shown in the picture on the right), you will get a Fresnel lens. The lens is cut by a CAD/CAM processing center with diamonds. There are as many as 10,000 different lens profiles on one screen. The investment in rear projection screen molds is huge. DNP is the only rear projection screen manufacturer with its own mold factory. Therefore, each series of DNP products has a different focal length; the size of each section u003d the dot pitch (resolution) of the screen. 3. Schematic diagram of the working principle of Fresnel lens and cylindrical lens and the working principle after combination

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The combination of Fresnel and cylindrical lenses can achieve a horizontal viewing angle of 180 degrees, and the wide-angle series of DNP screens thus gain a huge market share in the world. It has become the most popular screen on the market for many years, suitable for various applications.

The combination of Fresnel and fog lens is also one of DNP's nine screen series. It is specially developed for some special applications and has been put on the market a few years ago. However, because the viewing angle is not as good as the wide-angle screen series, the applicable area is narrow, DNP company only uses it as a supplementary product.

4. The difference between a double-layer screen and a single-layer screen

Double-layer screen has the following characteristics: it has better brightness uniformity than single-layer screen; it is very suitable for short-distance projection; it is very suitable for multi-screen splicing.

5. The working principle diagram of the two filter systems of DNP's double-layer screen to increase the contrast

The first type: high-contrast cylindrical lens optical principle: (UCS/RUCS screen)

The surface of the optical lens between the two lenses is covered with a layer of melanin, which can absorb ambient light. The cylindrical lens can pick up the light from the projector and transmit it to the viewer, while the ambient light in front will be absorb.

The second type: high contrast glass beads optical principle: (BB screen)

This technique uses fine black glass beads and sprays a layer of melanin on one side. The black glass beads can pick up the light from the projector and transmit it to the viewer. The ambient light shining on the screen is directly absorbed.