Band-pass light-filtering-piece capable of reducing coating-plated layers

Abstract

The invention discloses a band-pass filter able to reduce number of coatings, comprising: a substrate, a main membrane stacked on the substrate and stacked with a (LHxLH)m film structure, a first matching membrane placed in between the main membrane and the substrate and having an average penetration ratio >85% in the first corrected wave band, and a second matching membrane stacked on the main membrane and having an average penetration ratio >95% in the second corrected wave band, where the average penetration ratio of the main membrane is greater than 80% in the first wave band and those of the main membrane are between 40% and 60%in the second and third wave bands, and those of the main membrane are less than 1% in the fourth and fifth wave bands, and x=2n, and n is a positive integer and m<=6; the second wave band is between the first and fourth wave bands, the third wave band is between the first and fifth wave bands and the wavelengths of the second and third wave bands are less than and greater than that of the first wave band, respectively; the first wave band is in the first corrected wave band and the second corrected wave band is in the first wave band.

Description

technical field [0001] The invention relates to a band pass filter, in particular to a band pass filter which can reduce the number of coating layers. Background technique [0002] At present, the film layer structure of the band-pass filter can be divided into two common ways: one is double-sided optical coating, taking the visible light band-pass filter as an example, which is divided into two planes on a glass substrate. Coated with an ultraviolet cut (UV cut) coating and a far infrared cut (IR cut) coating; the other is a single-sided optical coating, taking the green bandpass filter as an example, it is on a glass substrate Dozens of high and low value refractive layers of equal thickness are plated on one of the planes. [0003] Generally, the band-pass filter composed of double-sided optical coating not only affects the final transmittance due to the total film thickness accumulated on both sides is too thick, but also must consider the single-sided optical spectrosc...

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Problems solved by technology

[0011] Referring to Fig. 3, it is shown by the transmittance spectrogram of this bandpass filter 1 that the transmittance curve after the stack 12, 13, 14 is superimposed is serious jitter (ripper), and due to the The total film thickness of the bandpass filter 1 is as high as about 8000nm, which can easily cause the scattering phenomenon and cause the average transmittance to be unable to be maintained above 80%. Therefore, not only the production cost of the coating is increased, but also the The optical splitting properties of the bandpass filter 1

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