Projection lens and projection apparatus

Abstract

A projection lens for projecting an image beam is provided. The image beam is converted by a light valve from an illumination beam irradiating the light valve. The projection lens includes a first lens group, a second lens group, and a third lens group. The first lens group is disposed on a transmission path of the image beam, and has a first optical axis. The second lens group is disposed on both a transmission path of the illumination beam and the transmission path of the image beam, and between the light valve and the first lens group. The second lens group has a second optical axis. The second optical axis is inclined with respect to the first optical axis. The third lens group is disposed on the transmission path of the image beam, and between the first lens group and the second lens group. A projection apparatus is also provided.

Description

technical field [0001] The invention relates to an optical element and a display device, and in particular to a projection lens and a projection device. Background technique [0002] Among various types of display devices, the projection device has the characteristic of being able to project a large-sized image frame several times larger than the surface area of ​​the device with a smaller device volume, so it has an irreplaceable advantage in the display field. Since the projection device images the image of the light valve on the screen through the projection lens, the image quality is greatly affected by the imaging quality of the projection lens. Therefore, the projection lens is a very important optical element in the projection device. [0003] Since the projection device is usually set on the desktop or hung upside down on the ceiling, the light valve of the projection device usually has an offset greater than 100% relative to the optical axis of the projection lens,...

AI Technical Summary

Problems solved by technology

When the offset of the light valve is above 100%, it means that the offset of the light valve relative to the projection lens is relatively large, so it is easy to cause the volume of the entire optical system to be difficult to reduce

If in order to reduce the volume of the optical system so that the projection system can be applied in portable electronic devices, the part on the other side of the offset of the projection lens relative to the light valve can be trimmed, but this is easy to cause The effective area (clear aperture) of the image beam is greatly cut off, resulting in a significant decrease in the brightness of the image screen

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