A wide-angle lens with aspherical cemented lenses

Abstract

The invention provides a wide-angle camera lens with an aspherical cemented lens. The wide-angle camera lens comprises a first lens, a second lens, a third lens, a fourth lens and a fifth lens in sequence from an object space to an image space, wherein the first lens, the second lens and the fourth lens have negative focal power, the third lens and the fifth lens have positive focal power, the fourth lens and the fifth lens are adhered together to form a cemented lens with the positive focal power, an adjoining plane of the cemented lens is at least a quadratic or above aspherical surface, the condition that BFL (Back Focal Length) / EFL (Effective Focal Length) is not smaller than 3.0 is also satisfied, BFL is a distance from an outermost point at the image space of a fifth lens element ofthe wide angle camera lens to an imaging plane, and EFL is a focal length value of the wide angle camera lens. The wide-angle camera lens can be used for realizing characteristics of a wide angle, small distortion, a large relative aperture, an ultra-long TTL (Total Length of Lens) and BFL under the condition of lower cost, and ensuring a comparatively perfect imaging definition within a wider temperature range, and is particularly suitable for outdoor monitoring under a relatively hostile environment and a vehicle-mounted camera system.

Description

technical field [0001] The invention relates to a wide-angle lens with an aspheric cemented lens, which is especially suitable for monitoring cameras and vehicle-mounted image systems that require longer total lens length TTL and working distance BFL and wider operating temperature conditions. Background technique [0002] At present, the wide-angle lens is generally composed of 5 to 8 lenses. For example, the wide-angle lens with the Chinese patent number 200910099703 is composed of 4 glass and 2 plastic lenses. However, the price of this wide-angle lens is relatively high, and it cannot meet customer requirements for low price and high performance. requirements. For this reason, there are also wide-angle lenses developed by Japanese companies that use aspheric technology to reduce costs. For example, the wide-angle lens with Chinese Patent No. 200880106079 is composed of 1 glass lens and 4 plastic lenses, but its light transmission performance is weak. The total length TT...

AI Technical Summary

Problems solved by technology

[0002] At present, the wide-angle lens is generally composed of 5 to 8 lenses. For example, the wide-angle lens with the Chinese patent number 200910099703 is composed of 4 glass and 2 plastic lenses. However, the price of this wide-angle lens is relatively high, which cannot meet customer requirements for low price and high performance. requirements

For this reason, there are also wide-angle lenses developed by Japanese companies that use aspheric technology to reduce costs. For example, the wide-angle lens with Chinese Patent No. 200880106079 is composed of 1 glass lens and 4 plastic lenses, but its light transmission performance is weak. The total length TTL and working distance BFL are also short, which cannot meet the special requirements of customers

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