Optical fingerprint recognition device and forming method thereof

Abstract

The invention provides an optical fingerprint recognition device and a forming method thereof. A lens array is formed through a gradually-changing luminous flux photoetching method so that requirements for manufacturing of a more exquisite and complex lens can be met, optical characters needed by the optical fingerprint recognition device are accurately guaranteed, and the optical fingerprint recognition device and the forming method thereof are suitable for a portable electronic device and are compatible with an existing chip manufacturing and packaging technology so that cost can be reduced.

Description

technical field [0001] The invention relates to the field of image processing, in particular to an optical fingerprint recognition device and a forming method thereof. Background technique [0002] The current fingerprint identification schemes include optical technology, silicon technology (capacitive / radio frequency type), ultrasonic technology, etc. [0003] Optical technology The use of optical imaging equipment is based on the principle of total reflection of light (FTIR). The light hits the surface of the glass with fingerprints, and the reflected light is obtained by the image sensor. The amount of reflected light depends on the depth of the fingerprint ridges and valleys pressed on the surface of the glass, as well as the oil and moisture between the skin and the glass. After the light is shot to the center of the valley through the glass, it is totally reflected at the interface between the glass and the air, and the light is reflected to the image sensor, while th...

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Problems solved by technology

[0004] However, the current optical fingerprint identification devices are large in size and have a long optical path, so they cannot be applied to portable electronic devices such as mobile phones

Under the premise of limited volume, the fingerprint recognition device suitable for portable electronic devices such as mobile phones needs to use a lens with a finer and more complex three-dimensional surface to ensure the required optical properties, such as resolution. However, using traditional micro-processing technology, For example, anisotropic or isotropic dry etching and wet etching can only process surfaces with limited topography, and newly developed three-dimensional micromachining technologies such as multi-layer mask technology, laser three-dimensional lithography, and electron beam direct writing technology , there are problems such as poor accuracy, high cost, and low output, which cannot meet the production requirements of such high-precision devices.

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