Optical fingerprint acquisition instrument without keystone distortions

Abstract

The invention provides an optical fingerprint acquisition instrument without keystone distortions. The optical fingerprint acquisition instrument comprises a shell, an acquisition board, an imaging device and a circuit board. The acquisition board at least comprises a transparent contact layer and a transparent luminescent layer which is positioned below the transparent contact layer; and the imaging device is positioned right blow the acquisition board. The acquisition board is characterized in that the transparent luminescent layer also includes a brightening reflection layer which is arranged under an acquisition luminescent zone. The optical fingerprint acquisition instrument uses the acquisition board as an acquisition component of fingerprint images, and the imaging device is positioned right below the acquisition board to ensure that the distances (optical distance) from an acquisition surface to imaging surfaces are accordant, and the keystone distortions of the fingerprint images are eliminated. The brightening reflection layer included in the transparent luminescent layer interior of the acquisition board reflects the light down emitted from the acquisition luminescent zone to the transparent contact layer, so that the light intensity irradiated on finger surfaces are increased, meanwhile the light without fingerprint information transmitted from the bottom of the acquisition board is reduced, thereby improving the contrast radio of the fingerprint acquisition images.

Description

Optical fingerprint collector without trapezoidal distortion technical field The invention relates to an optical fingerprint collector, in particular to an optical fingerprint collector without trapezoidal distortion. Background technique The optical fingerprint collection device is a fingerprint collection device widely used in the existing fingerprint identification system, which uses the optical difference caused by the difference of the ridge line and the valley line of the light on the interface to form an image and collect it. The optical fingerprint collector collects the surface texture image of the fingerprint. Specific light is irradiated on the surface of the finger to form reflected light. Since the ridges and valleys of the fingerprint are different, the amount of reflected light is also different. The reflected light passes through the imaging device Capture imaging. Since the collection device of the traditional optical fingerprint collection device usual...

AI Technical Summary

Problems solved by technology

However, the above method does not solve the root cause of image distortion. Since the condenser lens and image correction prism are installed separately, the size of the product and the complexity of the optical path will be increased, which will eventually lead to an increase in manufacturing costs and a decrease in production efficiency. reduce

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