A super wide-angle lens

Abstract

The invention discloses an ultra wide angle camera lens. The ultra wide angle 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, the condition that BFL (Back Focal Length) / EFL (Effective Focal Length) is not smaller than 2.4 is also satisfied, BFL is a distance from an outermost point at the image space of a fifth lens element of the ultra wide angle camera lens to an imaging plane, and EFL is a focal length value of the ultra wide angle camera lens. In the invention, the ultra wide angle camera lens remains a longer BFL under the condition that a TTL (Total Length of Lens) is kept so as to meet requirements for larger sizes of electronic elements and devices at the periphery of an image sensor during the design of a camera; and the lens elements and optical filters are further from the image sensor due to longer BFL, so that the requirement for the surface cleanliness of the respective lens elements and optical filters can be effectively reduced, and the camera is easier to assemble and produce.

Description

technical field [0001] The invention relates to a novel ultra-wide-angle lens, which is especially suitable for monitoring cameras and vehicle-mounted image systems that have higher requirements on the working distance of the lens and wider operating temperature conditions. Background technique [0002] At present, the ultra-wide-angle lens is generally composed of 5 to 8 lenses. For example, the ultra-wide-angle lens with the Chinese patent number 200910099703 is composed of 4 glass and 2 plastic lenses. However, this ultra-wide-angle lens is large in size and high in price, which cannot satisfy Customers demand small size, low price and high performance. For this reason, there are also ultra-wide-angle lenses developed by Japanese companies that use aspheric technology to reduce weight, cost, and deformation. For example, the ultra-wide-angle lens with Chinese Patent No. 200880106079 is composed of one glass lens and four plastic lenses. Its light transmission performance...

AI Technical Summary

Problems solved by technology

[0002] At present, the ultra-wide-angle lens is generally composed of 5 to 8 lenses. For example, the ultra-wide-angle lens with the Chinese patent number 200910099703 is composed of 4 glass and 2 plastic lenses. However, this ultra-wide-angle lens is large in size and high in price, which cannot satisfy Customers request small size, low price and high performance

For this reason, there are also ultra-wide-angle lenses developed by Japanese companies that use aspheric technology to reduce weight, cost, and deformation. For example, the ultra-wide-angle lens with Chinese Patent No. 200880106079 uses 1 glass lens and 4 plastic lenses. Its light transmission performance is weak, the working distance BFL is also short, and the temperature compensation characteristics are not good, which cannot meet the requirements of maintaining perfect imaging clarity in the temperature range of -40°C to +85°C

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