Prime lens

Abstract

The embodiment of the invention discloses a prime lens. The prime lens includes a first lens with negative light focal power, a second lens with negative light focal power, a third lens with positivelight focal power, a diaphragm, a fourth lens with negative light focal power, a fifth lens with positive light focal power, a sixth lens with positive light focal power, a seventh lens with negativelight focal power, and an eighth lens with positive light focal power, which are arranged successively along an optical axis from an object side to an image side, wherein the fourth lens and the fifthlens form an adhesive lens; the first lens, the fourth lens, the fifth lens, and the sixth lens are spherical lens; and the second lens, the third lens, the seventh lens, and the eighth lens are non-spherical lens. The technical scheme of the embodiment of the invention can be applicable to the field of security and defense. The lens has the characteristics of day and night confocal function, excessive large amount of light and an ultra-wide angle, especially suitable for use under a low illumination condition.

Description

Technical field [0001] The embodiment of the present invention relates to optical device technology, in particular to a fixed focus lens. Background technique [0002] With the improvement of people's safety awareness, there are also higher levels of requirements for security, and surveillance cameras were born. Compared with the zoom lens, the fixed focus lens is simple in design and manufacturing, the image of the moving object is clear and stable, and the picture is delicate, which makes it occupy an important position in the security monitoring industry. [0003] The current solution for night shooting of security cameras is dual-band confocal technology, that is, when there is sufficient light during the day, the camera adopts a visible light receiving mode; when in a low-light environment at night, the camera adopts a combined visible light and infrared (850nm) mode for monitoring , In order to ensure a greater amount of light; in order to achieve this function, the lens is ...

AI Technical Summary

Problems solved by technology

At night and dusk, greater light means better shooting results. The current mainstream lens aperture is F1.6, and there will still be problems such as lower frame rate and image lag in low-brightness environments.

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