Light guide module of optical fingerprint identification system

Abstract

The invention discloses a light guide module of an optical fingerprint identification system. The light guide module guides the reflected light to an image sampling device and comprises a press plate for light transmittance and at least one light diffusion plate. The press plate is provided with a plate surface for a finger to press. The light diffusion plate is arranged between the image sampling device and the press plate and provided with an opening and a plurality of micro structures formed on a surface and guiding the incident lights to disperse on the surface of the press plate, wherein the opening is opposite to the press plate and the image sampling device and allows the reflected light to pass through. Therefore, the micro structure ensures that the incident lights are distributed on the press plate by adopting the micro structures, thereby increasing the light brightness focused on the finger, and further effectively improving the recognition rate.

Description

【Technical field】 [0001] The invention relates to a light guide module, in particular to a light guide module of an optical fingerprint recognition system using optical fingerprint identification. 【Background technique】 [0002] refer to figure 1 , an optical fingerprint identification system 1, including an image-taking device 11, and a pressing plate 12 and a light-diffusing plate 13 arranged above the image-taking device 11 in sequence from top to bottom. The pressing plate 12 has a plate surface 121 for the finger A to press. The light diffusing plate 13 guides the incident light to form a surface light source projecting towards the pressing plate 12 and has a through hole 131 through which the reflected light passes. When the surface light source is projected onto the finger A by the light diffusion plate 13, it will be reflected to the imaging device 11 below. Since the crests of the fingerprint reflect light and the troughs absorb light, the reflected light will for...

AI Technical Summary

Problems solved by technology

[0005] However, since the light guide plate 22 guides the incident light according to the principle of total reflection, during the assembly process, the incident angle between the light source 23 and the light guide plate 22 must be precisely adjusted to effectively guide the incident light to project on the light guide plate 22. The various parts of finger B are not only difficult to assemble, but also costly to assemble, which is quite uneconomical

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