Narrow-band interference filter

Abstract

The invention discloses a narrowband interference filter which comprises substrate which is made of quartz glass materials. The upper surface and the lower surface of the substrate are respectively plated with a main peak film system and a section secondary peak film system, wherein the main peak film system is a four half-wave film system and the section secondary peak film system is a section secondary peak film pack. The narrowband interference filter is good in optical performance, high in transmittance of a passing band, deep in stopping band ending, small in oblique incidence drifting, high in stability, high in reliability, in addition, the passing band approaches to a rectangle, disturbance to identification of an active marker caused by sunlight and other stray light can be eliminated effectively when the narrowband interference filter is matched with the active marker to used, and identification accuracy is high.

Description

technical field [0001] The invention relates to an optical filter, in particular to a narrow-band interference optical filter. Background technique [0002] The design and development of interference filters (thin film interference filters) generally select substrate materials and film materials according to performance requirements, and use vacuum coating method to alternately form high or low refractive index with a certain thickness on the side of the substrate. The metal film-dielectric-metal film, or all-dielectric film, to form a multi-level series solid Fabry-Perot interferometer. [0003] At present, when designing narrow-band interference filters, the main considerations are usually the pass-band center wavelength, pass-band width and pass-band transmittance, and increasing the pass-band transmittance will generally reduce the stop-band cut-off depth, and vice versa. In general, if the transmittance of the passband is higher than 90%, the cutoff depth of the stopba...

AI Technical Summary

Problems solved by technology

It can be seen that it is difficult to obtain a narrow-band interference filter with both high pass-band transmittance and excellent stop-band cut-off depth at present.

[0004] In addition, the narrow-band interference filter has an oblique incidence effect. When the beam is obliquely incident, the pass-band will be short-shifted, the pass-band transmittance will be reduced, and the waveform will be deteriorated. However, when designing and developing narrow-band interference filters, most of them are rarely Consider the problem of reducing the influence of oblique incidence drift, and it does not involve the design of drift compensation

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