Big relative aperture long-focus image space telecentric zoom lens

Abstract

The invention discloses a big relative aperture long-focus image space telecentric zoom lens, sequentially comprising a front fixed group, a zoom group, a compensation group and a back fixed group from the object plane side to the image plane side; the corresponding combined focus satisfies a conditional equation: 3.5<F1 / FW<6, -1.6<F2 / FW<-0.9, 1.1<F3 / FW<2, 1.3<F4 / FW<1.9, wherein FW is the focus ofthe zoom lens in wide angle end state. The invention adopts the design of big relative aperture which reaches 1:2 and keeps constant big relative aperture in zoom process to ensure high light energyutilization rate of lens; bigger zoom ratio and longer focus ensure good imaging quality in zooming process; the lens adopt the image space telecentric design, so that the size of the image plane doesnot change with the movement of the image plane and the illumination is even; and all of the glass are made in China, with low cost. The big relative aperture long-focus image space telecentric zoomlens shows a wide application prospect in the fields of remote sensing, measurement, photography and the like.

Description

technical field [0001] The present invention relates to a zoom lens system, in particular to a lens system with large relative aperture, long focal length, image space telecentricity and continuous zoom, which is especially suitable for the front objective lens of a spectrum imager, and can also be used for measurement, fields of photography. Background technique [0002] Spectral imaging technology is an organic combination of spectral technology and imaging technology. While detecting the spatial characteristics of ground objects, it can obtain the spectral characteristics of ground objects in dozens or even hundreds of bands, which greatly improves the classification and identification of ground objects. It has shown broad application prospects in many fields such as the global environment and military affairs, and has become one of the most active frontiers in the development of remote sensing technology in the 1990s. [0003] In the 21st century, with the continuous de...

AI Technical Summary

Problems solved by technology

The fixed-focus lens restricts the imaging spectrometer to only image the scene at a specific distance from the ground. If the scene exceeds this specific range, the position of the imaging spectrometer must be adjusted to the ground, causing great inconvenience

[0004] In addition, the zoom lenses currently on the market and in patents generally have the following disadvantages: (1) the relative aperture of the lens is small and changes during the zooming process, and the utilization rate of light energy is not high; (2) the telecentricity of the image cannot be achieved. , so that the size of the image surface changes with the movement of the image surface, and the illumination is not uniform

In the Chinese invention patent with the publication number CN1409149A, a zoom lens system is disclosed with a relative aperture of 1 / 2.8 to 1 / 4.7 and a focal length of 7.4 to 21.3 mm; another example is the Canon EF-S zoom lens with a relative aperture of 1 / 4.7 mm. 3.5 to 1 / 5.6, focal length is 18 to 200mm, none of them can meet the requirements for the use of the front objective lens of the spectral imager

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