Long-focal-length iris identification object lens

Abstract

The invention relates to a long-focal-length iris identification object lens. The long-focal-length iris identification object lens comprises a front group, a rear group and an imaging group which are successively coaxially arranged at intervals. The front group comprises a first convex lens, a first doublet lens and a first concave lens which are successively arranged at intervals from an object side to an image side, and the first doublet lens is composed of a first sub concave lens and a first sub convex lens; the rear group comprises a second convex lens, a second concave lens and a second doublet lens, and the second doublet lens is composed of a second sub convex lens and a second sub concave lens; and the imaging group comprises a CMOS chip. The long-focal-length iris identification object lens provided by the invention makes up for the disadvantages of insufficient work distance of a conventional iris identification object lens, prolongs the work distance of an iris identification optical system, is of good imaging quality which is far beyond the demand of a large-view-field CMOS, and is high in resolution, simple in structure, easy to process and not high in overall cost, thereby being suitable for large-area popularization and application.

Description

technical field [0001] The invention relates to the field of optical technology, in particular to an iris recognition objective lens with a long focal length. Background technique [0002] The iris recognition objective lens used in general iris recognition products has a working distance of only 15-30cm, which can only realize close-range iris recognition. The particularity of the iris is that it absorbs ordinary visible light and reflects the infrared beam around 850nm. Therefore, according to this particularity, the camera for iris recognition needs special aberration correction for the near-infrared spectrum in order to collect to high-definition iris images. However, the resolution of general infrared objective lenses on the market is relatively low, and infrared objective lenses are mostly used for thermal imaging. The thermal imaging system corresponds to high spectral requirements and the size of the photosensitive Pixel corresponding to the Sensor is about 20um. Th...

AI Technical Summary

Problems solved by technology

However, the resolution of general infrared objective lenses on the market is relatively low, and infrared objective lenses are mostly used for thermal imaging. The thermal imaging system corresponds to high spectral requirements and the size of the photosensitive Pixel corresponding to the Sensor is about 20um. This type of infrared objective lens is suitable for our application. is impractical

The ordinary imaging objective lens has a spectrum of 400-700nm, and there is no special correction in the infrared band

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