Ultra wide angle camera lens

Abstract

An ultra wide-angle lens, including successively from object space to image space: a first lens (L1) and a second lens (L2) having negative focal power, a third lens (L3) having positive focal power, a fourth lens (L4) having negative focal power and a fifth lens (L5) having positive focal power. A gluing lens having positive focal power is formed by gluing the fourth lens (L4) and the fifth lens (L5) together, which satisfies BFL / EFL = 2.4, where BFL is the distance between the most exterior point on the image space side of the fifth lens and the imaging surface in the ultra wide-angle lens, and EFL is the focal length of the ultra wide-angle lens. In the case of a shorter total length TTL, an ultra wide-angle lens has a comparatively longer lens back focal length BFL, to satisfy the requirement for larger-sized peripheral electronics of an imaging sensor during camera design, and a longer BFL causes lens components and optical filters to be located at a farther position from the imaging sensor, which can effectively lower the requirements of cleanliness of the surface of each lens component and optical filter, and make the assembly and manufacturing of cameras much easier.

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

Images