CN217543435U - Optical filter - Google Patents

Abstract

The utility model relates to an optical filter, which comprises a substrate (1), and a band-pass film (2) and an antireflection film (3) which are arranged on two sides of the substrate (1), wherein the band-pass film (2) and the antireflection film (3) are formed by alternately arranging high-refractive-index film layers and low-refractive-index film layers; the transmittance of the optical filter in a wavelength band of 1000nm to 2000nm is more than 95% under an incident angle of 0 to 50 degrees. The optical filter of the utility model can realize high transmittance at an incident angle of 0-50 degrees within a wave band of 1000-2000 nm.

Description

Optical filter

Technical Field

The utility model relates to a light filter.

Background

With the development of science and technology, laser detection technology is widely applied to distance detection, biological identification and various industrial productions. Therefore, the requirement for the laser interference rejection capability is also increasing. According to the laser detection principle, the anti-interference capability of the laser can be effectively improved along with the red shift of the laser detection wavelength. However, in the prior art, the infrared laser product near the 940nm wave band cannot meet the requirement of high anti-interference capability. In addition, the long shift of the laser wave band will inevitably result in the increase of the film thickness, and further cause the film layer to have larger stress, so that the surface of the lens is easy to generate distortion. The light rays can generate reflection loss after passing through the distorted surface, and the energy value of the reflection loss is closely related to the surface distortion, namely the larger the distortion is, the more the energy loss is, so that the transmittance of the product can be seriously reduced. It can be seen that the above-mentioned drawbacks of the prior art put higher demands on the infrared laser products with longer wavelength.

SUMMERY OF THE UTILITY MODEL

An object of the utility model is to provide an optical filter.

In order to realize the above object, the utility model provides an optical filter, be in including base plate and setting the band pass membrane and the antireflection coating of base plate both sides, the band pass membrane with the antireflection coating forms by high, low refracting index rete alternate arrangement.

According to an aspect of the present invention, the material refractive index of the high refractive index film layer is above 2.0, and the material refractive index of the low refractive index film layer is below 2.0.

According to an aspect of the present invention, the material of the high refractive index film layer in the band pass film includes germanium oxide, titanium oxide, niobium oxide, tantalum oxide, silicon hydride, titanium hydride, germanium hydride, niobium hydride, tantalum hydride, lanthanum hydride, silicon nitride, germanium nitride, titanium nitride, niobium nitride, tantalum nitride, lanthanum nitride, silicon hydrogen nitride, germanium hydrogen nitride, titanium hydrogen nitride, niobium hydrogen nitride, tantalum hydrogen nitride, lanthanum hydrogen nitride;

the low-refractive-index film layer in the band-pass film is made of silicon oxide, magnesium fluoride and cryolite.

According to one aspect of the present invention, the material of the high refractive index film layer in the antireflection film includes titanium oxide, niobium oxide, tantalum oxide, lanthanum oxide, hafnium oxide, zirconium oxide, and germanium oxide;

the low-refractive-index film layer in the antireflection film is made of aluminum oxide, magnesium oxide, silicon oxide, magnesium fluoride, lanthanum fluoride and aluminum fluoride.

According to an aspect of the utility model, the thickness of band pass membrane is between 10000nm-20000nm, the thickness of antireflection coating is between 10000nm-20000 nm.

According to an aspect of the present invention, a ratio of the thickness of the bandpass film to the thickness of the antireflection film is between 1 to 1.8.

According to one aspect of the present invention, the band pass film has 15-30 pairs of high and low refractive index film layers;

the antireflection film has 20-50 pairs of high and low refractive index film layers.

According to one aspect of the present invention, the transmittance of the optical filter is above 95% in the wavelength range of 1000nm to 2000nm at an incident angle of 0 ° to 50 °.

According to an aspect of the invention, the surface PV value of the optical filter is less than 20 microns within a diameter of 17 mm.

According to the design of the utility model, the reasonable selection of the coating material and the thickness of the film layer enables the optical filter to realize high transmittance in the wave band of 1000nm-2000nm under the incidence of a large angle within the range of 0-50 degrees. And the PV value of the lens surface profile within the diameter of 17mm can be ensured to be less than 20 microns.

According to the utility model discloses a scheme makes the thickness of band pass membrane and the proportion of the thickness of antireflection coating satisfy certain relation to realization stress balance that can be better.

According to the utility model discloses a scheme, when making the light filter, plate earlier and make the great band pass membrane of stress, plate the system anti-reflection coating again to carry out the system of plating of anti-reflection coating under high temperature environment, thereby can the effectual stress that eliminates the rete.

Drawings

Fig. 1 is a schematic diagram showing a structure of an optical filter according to an embodiment of the present invention;

fig. 2 schematically shows a spectral diagram of an optical filter according to an embodiment of the present invention at 1300 nm;

fig. 3 schematically shows a spectrum diagram of an optical filter of an embodiment of the present invention at 1550 nm;

fig. 4 schematically shows a spectrum diagram of an optical filter according to an embodiment of the present invention at a wavelength of 1800 nm.

Detailed Description

In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings used in the embodiments will be briefly described below. It is obvious that the drawings in the following description are only some embodiments of the invention, and that for a person skilled in the art, other drawings can be derived from them without inventive effort.

In describing embodiments of the present invention, the terms "longitudinal," "lateral," "up," "down," "front," "back," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," and other terms are used in an orientation or positional relationship shown in the associated drawings for convenience in describing the invention and for simplicity in description, and are not intended to indicate or imply that the referenced device or element must have a particular orientation, be constructed and operated in a particular orientation, and are not to be construed as limiting the invention.

The present invention will be described in detail with reference to the accompanying drawings and specific embodiments, which are not repeated herein, but the present invention is not limited to the following embodiments.

Referring to fig. 1, the (bandpass) filter of the present invention includes a substrate 1, and a bandpass film 2 and an antireflection film 3 disposed on two sides of the substrate 1, wherein the bandpass film 2 and the antireflection film 3 are formed by alternately arranging high refractive index film layers and low refractive index film layers. Wherein, the material refractive index of the high refractive index film layer is more than 2.0, and the material refractive index of the low refractive index film layer is less than 2.0. In the utility model, the band-pass film 2 has 15-30 pairs of high and low refractive index film layers, and the antireflection film 3 has 20-50 pairs of high and low refractive index film layers.

In the present invention, the material of the high refractive index film layer in the band pass film 2 may be metal, semiconductor, and all or part of oxide, nitride, hydride, hydroxide, and oxynitride thereof. For example, one or more mixtures (e.g., a mixture of titanium oxide and lanthanum oxide, a mixture of lanthanum oxide and aluminum oxide) of germanium oxide, titanium oxide, niobium oxide, tantalum hydride, titanium hydride, germanium hydride, niobium hydride, silicon nitride, germanium nitride, titanium nitride, niobium nitride, tantalum nitride, lanthanum nitride, silicon nitride hydride, germanium nitride hydride, titanium nitride hydride, niobium nitride hydride, tantalum nitride hydride, and lanthanum nitride hydride. The material of the low refractive index film layer in the band-pass film 2 comprises one or a mixture of silicon oxide, magnesium fluoride and cryolite. Thus, the selection of these materials can enable the filter to achieve high transmission at high angle incidence within a certain wavelength band.

The material of the high refractive index film layer in the antireflection film 3 is a metal oxide, for example, one or a mixture of titanium oxide, niobium oxide, tantalum oxide, lanthanum oxide, hafnium oxide, zirconium oxide, and germanium oxide. The material of the low refractive index film layer in the antireflection film 3 includes one or a mixture of more of aluminum oxide, magnesium oxide, silicon oxide, magnesium fluoride, lanthanum fluoride and aluminum fluoride. Meanwhile, the materials of the low refractive index film layer and the materials of the high refractive index film layer can be mixed into other mixtures.

Of course, in the bandpass film 2 and the antireflection film 3, the material of the high refractive index film layer and the low refractive index film layer is not limited to one of the above, and various film layers may be selected to form various film systems.

In the utility model, the thickness of the band-pass film 2 is between 10000nm-20000nm, and the thickness of the anti-reflection film 3 is between 10000nm-20000 nm. Moreover, as the film layer of the antireflection film 3 is thickened, the stress of the film layers on the two sides of the substrate 1 can be gradually kept relatively balanced. Therefore, the utility model discloses set up the proportion of the thickness of band pass film 2 and the thickness of antireflection coating 3 between 1 to 1.8 to realize the balance of stress.

The optical filter of the present invention is described in detail below in three different band embodiments:

first embodiment

Referring to fig. 2, the compositions of the bandpass film 2 and the antireflection film 3 in the optical filter of the present embodiment are shown in table 1 below:

TABLE 1

Second embodiment

Referring to fig. 3, the compositions of the bandpass film 2 and the antireflection film 3 in the optical filter of the present embodiment are shown in table 2 below:

TABLE 2

Third embodiment

Referring to fig. 4, the compositions of the bandpass film 2 and the antireflection film 3 in the optical filter of the present embodiment are shown in table 3 below:

TABLE 3

In the preparation method of the optical filter of the utility model, firstly, one side of the substrate 1 is plated with the band-pass film 2, and then the other side of the substrate 1 is plated with the antireflection film 3. In addition, the plating of the antireflection film 3 should be performed at a high temperature of 150 ℃ or higher, so that the film-formed bandpass film 2 can be baked at a high temperature to release stress during the plating of the antireflection film 3, and the stress of the antireflection film 3 can be used to gradually balance the stress of the bandpass film 2. In addition, the first layer is required to be made of silicon dioxide material during plating, the ion source power of the plating film is about 1.5 times higher than that of the rest layer of silicon dioxide, and the plating rate is about 0.8 times lower than that of the rest layer of silicon dioxide.

The setting is satisfied, and the transmittance of the optical filter in any near infrared band of 1000nm-2000nm is more than 95% under the incident angle of 0-50 degrees. The special structure design of the optical filter can ensure that the surface PV value of the optical filter is less than 20 microns within 17mm of the diameter.

The above description is only an embodiment of the present invention and is not intended to limit the present invention, and various modifications and changes may be made by those skilled in the art. Any modification, equivalent replacement, or improvement made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims (5)

1. The optical filter is characterized by comprising a substrate (1), and band-pass films (2) and antireflection films (3) which are arranged on two sides of the substrate (1), wherein the band-pass films (2) and the antireflection films (3) are formed by alternately arranging high-refractive-index film layers and low-refractive-index film layers;

the transmittance of the optical filter in a wavelength band of 1000nm to 2000nm is more than 95% at an incident angle of 0 to 50 degrees;

the thickness of the band-pass film (2) is 10000nm-20000nm, and the thickness of the antireflection film (3) is 10000nm-20000 nm;

the ratio of the thickness of the band-pass film (2) to the thickness of the antireflection film (3) is 1.

2. The filter according to claim 1, wherein the high refractive index film layer has a material refractive index of 2.0 or more, and the low refractive index film layer has a material refractive index of 2.0 or less.

3. The filter according to claim 2, wherein the material of the high refractive index film layer in the bandpass film (2) is one of germanium oxide, titanium oxide, niobium oxide, tantalum oxide, lanthanum oxide, silicon hydride, titanium hydride, germanium hydride, niobium hydride, tantalum hydride, lanthanum hydride, silicon nitride, germanium nitride, titanium nitride, niobium nitride, tantalum nitride, lanthanum nitride, silicon hydrogen nitride, germanium hydrogen nitride, titanium hydrogen nitride, niobium hydrogen nitride, tantalum hydrogen nitride, lanthanum hydrogen nitride;

the low-refractive-index film layer in the band-pass film (2) is made of one of silicon oxide, magnesium fluoride and cryolite.

4. The filter according to claim 2, wherein the material of the high refractive index film layer in the antireflection film (3) is a metal oxide;

the low-refractive-index film layer in the antireflection film (3) is made of one of aluminum oxide, magnesium oxide, silicon oxide, magnesium fluoride, lanthanum fluoride and aluminum fluoride.

5. The filter of claim 1, wherein the filter has a surface PV value of less than 20 microns within 17mm of diameter.

Images