Wide-angle lens

Abstract

The invention discloses wide-angle lens, and the lens sequentially comprises a first group G1, an aperture diaphragm STP and a second group G2 from the object plane to the image plane. An imaging plane IMG is provided with a light receiving surface of a solid photographing element. The first group G1 consists of a first lens L1 with the negative focal power, a second lens L2 with the negative focal power, and a third lens L3 with the positive focal power, wherein the first, second and third lenses L1, L2 and L3 are arranged coaxially. The front surfaces of the first and second lenses L1 and L2 are convex surfaces, and the rear surfaces of the first and second lenses L1 and L2 are concave surfaces. The second group G2 consists of a fourth lens L4 with the positive focal power, a fifth lens L5 with the positive focal power, a sixth lens L6 with the negative focal power and a seventh lens L7 with the positive focal power, wherein the fourth, fifth, sixth and seventh lenses L4, L5, L6 and L7 are arranged coaxially. The fifth lens L5 and the sixth lens L6 form a glued lens, and the gluing surface of the glued lens is bent towards the object space. The first group G1 and the second group G2 are connected through a thread connection frame, and are respectively located outside and inside a gate. The distance between two groups is changed through the rotation of a thread.

Description

technical field [0001] The invention relates to a wide-angle lens, in particular to a wide-angle lens for cat eyes. Background technique [0002] The technical problem or purpose to be solved: (The technical problem refers to solving the difficulties or existing problems encountered in the current production, and it can also be a new creation that brings convenience to people.) Cat's eye, also known as door mirror, is a decorative A small optical instrument on the door of a residence, which is convenient for residents to observe the outdoor situation. Has become a necessity for home security. Looking out from the door through the door mirror, you can see all the scenes outside the door within a field of view of about 120 degrees, but you can't see anything indoors through the door mirror from outside the door. If this mirror is installed on the gate of a public house or a private apartment, it can play a certain role in preventing theft and safety of the family. [0003] ...

AI Technical Summary

Problems solved by technology

[0005] 1. The length of the lens cannot be changed and cannot adapt to different door thicknesses

[0006] At present, the existing electronic cat-eye lenses on the market all adopt an integrated optical system, and the total optical length cannot be changed.

The integrated design makes the cat-eye lens not adaptable when installed on doors of different thicknesses. In order to eliminate the influence of different door thicknesses, the lens and the mechanism shell can only be installed outside the door, and then connected to the door through wires. The sensor part obtains image information

Such a cat-eye lens design is very low in safety, and criminals can easily destroy the internal circuit of the mechanism from outside the door, making the entire device unusable

[0007] 2. The length of the lens can be changed, but the field of view is reduced and the image quality is deteriorated

At present, the optical system adopted by most electronic cat-eye lenses on the market has a relatively small field of view, which cannot realize a wide range of shooting and monitoring, and has a large dead angle area, which poses certain safety hazards.

Moreover, in order to adapt to different door thicknesses, in the process of changing the length of the lens, the performance of the lens has been sacrificed, and the field of view has been greatly reduced.

[0009] 3. Low resolution

[0010] The resolution of the optical system of the cat-eye lens on the market is generally poor, and the resolution is below 1.3 million pixels, resulting in poor clarity of the entire optical system and poor user experience.

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