3D identification optical filter

Abstract

The invention discloses a 3D identification optical filter. The 3D identification optical filter is provided with a passband which is partially overlapped with a wavelength range of 800nm to 1800nm, and a cut-off band which comprises a range of 380nm to 750nm. The 3D identification optical filter comprises a substrate and optical filter film layers plated on two surfaces of the substrate, whereinthe optical filter film layer on one surface is formed by stacking a high refractive index layer, a medium refractive index layer and a low refractive index layer; and the optical filter film layer onthe other surface is formed by stacking at least two material layers. The 3D identification optical filter maintains a high cut-off degree and narrow transition band width while realizing small wavelength offset at a large light incident angle.

Description

technical field [0001] The invention relates to the field of optical filters, in particular to a 3D identification optical filter. Background technique [0002] Three-dimensional (3D) recognition technology has been widely used in fields such as machine vision, virtual reality, identity recognition, and automatic driving. Compared with two-dimensional imaging, 3D recognition can obtain the three-dimensional information of the detected object. The basic principle of 3D recognition is to emit infrared light of a certain band, and use the sensor to receive the light of this band returned by the detected object, and use signal processing to obtain distance information, thereby establishing a three-dimensional model of the detected object. The transmitter of a typical 3D recognition module includes an infrared light source, a modulation device, and a lens, and the receiver includes an infrared detector, lens, and infrared filter. [0003] For 3D recognition, the infrared filter...

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Problems solved by technology

[0009] However, the existing 3D optical filter is based on the multi-cavity bandpass film system with high and low refractive indices as mentioned above, and there are still some problems: a) Si:H material has a strong absorption of light below 600nm wavelength, but There is no complete absorption of light in the 600-800nm ​​wavelength range, which makes it difficult for the filter to have a high cut-off in this range; b) further reducing the angle drift requires increasing the order of the cavity layer. In order to maintain the bandwidth of the passband, improve The number of cavity layers inevitably increases the mismatch between the optical cavities, resulting in poor jitter of the filter and widening of the transition band; c) Due to the influence of b), in order to maintain the jitter of the filter, it is necessary Significantly increase the number of cavities, resulting in a significant increase in the number of filter film layers, increasing the difficulty of preparation

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