DLP long back work distance zooming projection lens

Abstract

This invention relates to a kind of varifocal projection lens of DLP long-back operating distance. The main character is that: the optical system is made up of the focusing group U1 with the negative power and the varifocal group U2 with the positive power and the compensating group U3 with the positive power. The U1, U2 and U3 are arrayed along the light axis from the screen side to the plane. The focusing is reached by moving the U1 group from ahead and back; the varifocal function is reached by moving the U2 and U3 from wide-angle end to telephoto end. In the varifocal progress, the distance from the first side of lens to the image side does not change, which can get the good imaging quality in the image side of long-back operating distance. The lens is the sphere lens. The process is good and proper for batch production.

Description

technical field [0001] The invention belongs to the technical field of optical appliances, and is a zoom projection lens with a long rear working distance suitable for use with a non-telecentric illumination light path on a DLP projector. Background technique [0002] DLP projection display technology has developed rapidly in recent years, and its development trend is to realize large-screen, high-definition, high-brightness image display on a short projection distance, and it can realize product features such as small size and light weight. The core component of DLP technology mainly adopts DMD digital image chip; DMD is a digital image chip exclusively mastered and developed by Texas Instruments. There are not many patented technologies in the system, and the existing LCD, LCOS and other projection lenses use a telecentric optical system, which cannot fully meet the supporting requirements of the DMD digital image chip. The image digital signal will be flipped by 10 or 12...

AI Technical Summary

Problems solved by technology

The core component of DLP technology mainly adopts DMD digital image chip; DMD is a digital image chip exclusively mastered and developed by Texas Instruments. There are not many patented technologies in the system, and the existing LCD, LCOS and other projection lenses use a telecentric optical system, which cannot fully meet the supporting requirements of the DMD digital image chip. The image digital signal will be flipped by 10 or 12 degrees, and the light beam from the lighting source will be reflected by the flip of the micro-mirror into the entrance pupil of the projection lens and focused on the screen. Based on this feature, projection lenses such as LCD and LCOS often cannot Fully meet the supporting requirements of DMD digital image chips

[0003] In addition, in the existing disclosed zoom projection lens technology, part of the application of aspheric technology, that is, by adding an aspheric lens to the optical system of the zoom projection lens to improve the imaging quality of the system or simplify the system structure, but the aspheric lens The application requires strict processing and assembly, which is not conducive to the improvement of production efficiency and the reduction of cost. In the technology that does not use aspheric lenses, in order to achieve better optical performance, the technical measure is generally to increase the number of lenses. More than 12 pieces, or high-grade optical materials with high refractive index imported from abroad, such as FCD1, which can significantly improve the aberration, are expensive, poor in workmanship, and low in processing efficiency and yield.

In a zoom projection lens disclosed in Japanese Patent No. 02120574, the materials used include FCD1, LAF and other high-grade materials, and the number of lenses is more than 12, so there are also problems such as high cost and low work efficiency.

In addition, when the optical system has a long back working distance, its aberration correction becomes very difficult, and the DLP projection system sometimes needs a long back working distance to meet the lighting requirements of the system

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