阅读说明：本技术 滤光片与电子设备 (Optical filter and electronic equipment ) 是由 于甄 李守军 严振兴 孔德兴 于 2019-10-21 设计创作，主要内容包括：本申请提供了一种滤光片与电子设备。该滤光片包括：基底,具有第一表面和与第一表面相对的第二表面,基底的吸收波长在650～700nm之间；第一折射率匹配单元,设置在第一表面上,第一折射率匹配单元包括交替设置的第一折射率层和第二折射率层,第一折射率层的折射率与第二折射率层的折射率不同。该滤光片的基底可以吸收波长在650～700nm之间的光波,即对发生偏移的部分进行吸收截止,消除了光谱漂移,避免了光谱漂移导致的RGB颜色比例变化造成的成像失真。(The application provides an optical filter and an electronic device. The optical filter includes: the substrate is provided with a first surface and a second surface opposite to the first surface, and the absorption wavelength of the substrate is 650-700 nm; and a first index matching unit disposed on the first surface, the first index matching unit including a first index layer and a second index layer alternately disposed, a refractive index of the first index layer being different from a refractive index of the second index layer. The substrate of the optical filter can absorb light waves with the wavelength of 650-700 nm, namely, the offset part is absorbed and cut off, so that the spectrum drift is eliminated, and the imaging distortion caused by the change of the RGB color proportion caused by the spectrum drift is avoided.)

1. An optical filter, comprising:

a substrate (10) having a first surface and a second surface opposite to the first surface, the substrate (10) having an absorption wavelength between 650 and 700 nm;

a first index matching unit (20) disposed on the first surface, the first index matching unit (20) including a first index layer and a second index layer alternately disposed, a refractive index of the first index layer being different from a refractive index of the second index layer.

2. The filter according to claim 1, wherein the substrate (10) comprises a transparent matrix material and an absorbing material, the absorbing material has an absorption wavelength between 650 and 700nm, the lens matrix material has a light transmittance greater than or equal to 90%, and preferably the transparent matrix material comprises a cyclic olefin polymer.

3. The filter of claim 2, wherein the absorbing material is dispersed in the transparent matrix material.

4. A filter according to claim 2, wherein the substrate (10) comprises a base layer (11) and an absorbing layer (12) disposed on at least one surface of the base layer (11), the base layer (11) comprising the transparent base material, the absorbing layer (12) comprising the absorbing material.

5. A filter as claimed in claim 1, wherein one of the first and second refractive index layers is a first low refractive index layer (21) and the other is a first high refractive index layer (22), and the refractive index of the first low refractive index layer (21) is smaller than that of the first high refractive index layer (22); preferably, the material of the first low refractive index layer (21) is selected from SiO₂、MgF₂Cryolite and Al₂O₃Of the first high refractive index layer (22) is selected from TiO₂、Ta₂O₅、Nb₂O₅OS50, ZnS, SiN and HfO₂At least one of (1).

6. A filter according to claim 1, further comprising:

a second index matching unit (30) disposed on the second surface, the second index matching unit (30) including a third index layer and a fourth index layer alternately disposed, a refractive index of the third index layer being different from a refractive index of the fourth index layer.

7. A filter as claimed in claim 6, characterised in that one of the third and fourth refractive index layers is a second low refractive index layer (31) and the other is a second high refractive index layer (32), the refractive index of the first low refractive index layer (21) being less than that of the first high refractive index layer (22); preferably, the material of the second low refractive index layer (31) is selected from SiO₂、MgF₂Cryolite and Al₂O₃Of the second high refractive index layer (32) is selected from TiO₂、Ta₂O₅、Nb₂O₅OS50, ZnS, SiN and HfO₂At least one of (1).

8. The optical filter according to claim 1, wherein the thickness of the first refractive index layer and/or the thickness of the second refractive index layer is between 8 and 300 nm.

9. The filter of claim 6, wherein the thickness of the third refractive index layer and/or the thickness of the fourth refractive index layer is between 8 and 300 nm.

10. An electronic device comprising an optical filter, wherein the optical filter is the optical filter according to any one of claims 1 to 9.

Technical Field

The application relates to the field of materials, in particular to an optical filter and electronic equipment.

Background

Along with the wide popularization of electronic products with camera shooting functions, such as smart phones, people have increasingly improved requirements on the functionality of the electronic products, especially camera shooting performance, and the trend of light and thin electronic products is developed, so that the design requirements on the camera shooting module are increasingly improved, that is, the camera shooting module can bear a larger incident light angle (more than 30 degrees), and the camera shooting definition and high reduction degree are ensured.

The blue glass infrared Cut Filter (IRCF for short) or blue film IRCF used in the market at present can only Cut off a band within an angular drift range of 0-30 degrees without moving, that is, basically ensures that the wavelength of three primary colors does not drift under an angle of 0-30 degrees, but eliminates spectral drift caused by incidence of a larger angle, thereby avoiding imaging distortion caused by RGB color ratio change caused by the spectral drift.

The above information disclosed in this background section is only for enhancement of understanding of the background of the technology described herein and, therefore, certain information may be included in the background that does not form the prior art that is already known in this country to a person of ordinary skill in the art.

Disclosure of Invention

The present disclosure provides an optical filter and an electronic device to solve the problem of imaging distortion caused by the optical filter at a large incident angle in the prior art.

In order to achieve the above object, according to one aspect of the present application, there is provided an optical filter including: a substrate having a first surface and a second surface opposite to the first surface, the substrate having an absorption wavelength of 650 to 700 nm; and a first refractive index matching unit disposed on the first surface, the first refractive index matching unit including a first refractive index layer and a second refractive index layer alternately disposed, the first refractive index layer having a refractive index different from a refractive index of the second refractive index layer.

Further, the substrate comprises a transparent base material and an absorption material, the absorption wavelength of the absorption material is 650-700 nm, the light transmittance of the lens base material is greater than or equal to 90%, and preferably, the transparent base material comprises a cycloolefin polymer.

Further, the absorbing material is dispersed in the transparent base material.

Further, the substrate includes a base layer including the transparent base material and an absorption layer provided on at least one surface of the base layer, the absorption layer including the absorption material.

Further, the first refractive index layer andone of the second refractive index layers is a first low refractive index layer, and the other is a first high refractive index layer, and the refractive index of the first low refractive index layer is smaller than that of the first high refractive index layer; preferably, the material of the first low refractive index layer is selected from SiO₂、MgF₂Cryolite and Al₂O₃Wherein the material of the first high refractive index layer is selected from TiO₂、Ta₂O₅、Nb₂O₅OS50, ZnS, SiN and HfO₂At least one of (1).

Further, the optical filter further includes: and a second refractive index matching unit provided on the second surface, the second refractive index matching unit including a third refractive index layer and a fourth refractive index layer alternately provided, the third refractive index layer having a refractive index different from a refractive index of the fourth refractive index layer.

One of the third refractive index layer and the fourth refractive index layer is a second low refractive index layer, and the other is a second high refractive index layer, and the refractive index of the first low refractive index layer is smaller than the refractive index of the first high refractive index layer; preferably, the material of the second low refractive index layer is selected from SiO₂、MgF₂Cryolite and Al₂O₃Wherein the material of the second high refractive index layer is TiO₂、Ta₂O₅、Nb₂O₅OS50, ZnS, SiN and HfO₂At least one of (1).

Further, the thickness of the first refractive index layer and/or the thickness of the second refractive index layer is 8 to 300 nm.

Further, the thickness of the third refractive index layer and/or the thickness of the fourth refractive index layer is 8 to 300 nm.

According to another aspect of the present application, there is provided an electronic device including the optical filter, the optical filter being any one of the optical filters described above.

By applying the technical scheme of the application, the spectrum is subjected to short-shift along with the increase of the incident angle of light, the substrate of the optical filter can absorb light waves with the wavelength between 650-700 nm, namely, the shifted part is absorbed and cut off, the spectrum drift is eliminated, and the imaging distortion caused by the change of the RGB color proportion caused by the spectrum drift is avoided. The filter can keep good optical characteristics under the condition of large-angle incidence, and breaks through the limitation that the existing infrared cut-off filter is difficult to meet the color cast generated by larger-angle incidence. In addition, the optical filter further comprises a first refractive index matching unit, wherein the first refractive index matching unit comprises a first refractive index layer and a second refractive index layer which are alternately arranged, the first refractive index layer and the second refractive index layer with different refractive indexes form an interference film, when light waves with different wavelengths pass through the optical filter film, the transmissivity is different, so that the visible light has high transmittance, and the infrared region has a cut-off optical light splitting effect.

Drawings

The accompanying drawings, which are incorporated in and constitute a part of this application, illustrate embodiments of the application and, together with the description, serve to explain the application and are not intended to limit the application. In the drawings:

FIG. 1 shows a graph of the transmittance of a prior art blue glass IRCF as a function of wavelength;

FIG. 2 is a graph showing the transmittance of a prior art blue film IRCF as a function of wavelength;

fig. 3 is a schematic structural diagram of an optical filter provided in an embodiment of the present application;

fig. 4 is a schematic structural diagram of an optical filter provided in another embodiment of the present application;

FIG. 5 is a schematic diagram illustrating the principle of the angle elimination effect of the filter of FIG. 3;

FIG. 6 is a graph showing the transmittance of the filter of FIG. 3 as a function of wavelength;

fig. 7 is a schematic view illustrating a structure of a substrate in an optical filter according to another embodiment of the present application;

fig. 8 is a schematic structural diagram of a substrate in an optical filter according to still another embodiment of the present application.

Wherein the figures include the following reference numerals:

10. a substrate; 11. a substrate layer; 12. an absorbing layer; 20. a first index matching unit; 21. a first low refractive index layer; 22. a first high refractive index layer; 30. a second index matching unit; 31. a second low refractive index layer; 32. a second high refractive index layer.

Detailed Description

It should be noted that the following detailed description is exemplary and is intended to provide further explanation of the disclosure. Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs.

It is noted that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of example embodiments according to the present application. As used herein, the singular forms "a", "an" and "the" are intended to include the plural forms as well, and it should be understood that when the terms "comprises" and/or "comprising" are used in this specification, they specify the presence of stated features, steps, operations, devices, components, and/or combinations thereof, unless the context clearly indicates otherwise.

It will be understood that when an element such as a layer, film, region, or substrate is referred to as being "on" another element, it can be directly on the other element or intervening elements may also be present. Also, in the specification and claims, when an element is described as being "connected" to another element, the element may be "directly connected" to the other element or "connected" to the other element through a third element.

As described in the background, the present application provides an optical filter and an electronic device to solve the above technical problem of distortion of an image caused by a filter with a large incident angle.

In an exemplary embodiment of the present application, as shown in fig. 3 and 4, an optical filter is provided, which includes a substrate 10 and a first index matching unit 20, wherein the substrate 10 has a first surface and a second surface opposite to the first surface, and an absorption wavelength of the substrate 10 is between 650 nm and 700 nm; the first refractive index matching unit 20 is disposed on the first surface, and the first refractive index matching unit 20 includes a first refractive index layer and a second refractive index layer alternately disposed, and a refractive index of the first refractive index layer is different from a refractive index of the second refractive index layer.

The substrate in the optical filter can absorb light waves with the wavelength of 650-700 nm, the emergent spectrum generates a short shift phenomenon along with the increase of the incident angle of light, the substrate of the optical filter absorbs the light waves with the wavelength of 650-700 nm, as shown in fig. 5, namely, the shifted part is absorbed and cut off, the spectrum shift is eliminated, and as shown in fig. 6, the imaging distortion caused by the change of the RGB color proportion caused by the spectrum shift is avoided. The filter can keep good optical characteristics under the condition of large-angle incidence, and breaks through the limitation that the existing infrared cut-off filter is difficult to meet the color cast generated by larger-angle incidence. In addition, the optical filter further comprises a first refractive index matching unit, wherein the first refractive index matching unit comprises a first refractive index layer and a second refractive index layer which are alternately arranged, the first refractive index layer and the second refractive index layer with different refractive indexes form an interference film, when light waves with different wavelengths pass through the optical filter film, the transmissivity is different, so that the visible light has high transmittance, and the infrared region has a cut-off optical light splitting effect.

The substrate can be any substrate as long as the substrate absorbs light with the wavelength of 650-700 nm. Specifically, in an embodiment of the present application, the substrate includes a transparent base material and an absorption material, the light transmittance of the lens base material is greater than or equal to 90%, and the absorption wavelength of the absorption material is between 650 nm and 700 nm.

In the embodiment of the upper section, the absorbing material can be dispersed in the transparent matrix material, and the absorbing material and the transparent matrix material are blended and extruded to form the substrate, so that the manufacturing is simple; it is also possible that the material comprising the transparent base material and the material comprising the absorbing material form separate material layers, respectively, which are stacked to form the substrate, as is particularly the case in fig. 7, in which the transparent base material forms the base layer 11, the absorbing material forms the absorbing layer 12, and the absorbing layer 12 is provided on the surface of the base layer 11. Of course, the manner of forming the material layer is not limited to the specific case of fig. 7, and may be as shown in fig. 8, that is, the absorbing material forms two absorbing layers 12, the base material forms one base layer 11, and the two absorbing layers 12 are respectively disposed on two opposite surfaces of the base layer 11.

Of course, the substrate of the present application may also be made of a material capable of absorbing light with a wavelength between 650 nm and 700nm and serving as a transparent substrate, such as Cyclo Olefin Polymer (COP).

The substrate material of the present application may be any material that can be used as a substrate in the prior art, such as one or more of PET, PE, APET, COP, COC, PMMA, PC, etc., and those skilled in the art can select a suitable substrate material according to the actual situation.

The absorbing material is any material which can absorb light waves between 650 nm and 700nm and does not affect other optical properties of the optical filter as much as possible, such as an inorganic light absorber, and specifically can be metal oxide or metal salt, wherein the metal in the metal oxide or metal salt is copper, chromium, iron or cadmium; the organic light absorber can also be organic light absorber, specifically phthalocyanine, porphyrin or azo; the material can also be an organic-inorganic composite light absorber, specifically phthalocyanine metal chelate, porphyrin metal chelate or azo metal chelate, and the actual absorbing material can comprise one or more of the materials.

In another specific embodiment of the present application, one of the first refractive index layer and the second refractive index layer is a first low refractive index layer 21, and the other is a first high refractive index layer 22, and the refractive index of the first low refractive index layer 21 is smaller than the refractive index of the first high refractive index layer 22, so that the optical filter can simultaneously transmit light of three colors of red, green and blue, and transmit light of other colors except for the three colors of light, such as purple, cyan, yellow and orange, so as to purify white light, thereby improving the color gamut of incident light. Compared with the optical filter in the prior art, the optical filter has higher transmittance of red, green and blue.

The material of the first low refractive index layer and the material of the first high refractive index layer may be any material having a refractive index satisfying the above requirements and having a small influence on transmittance, and those skilled in the art may select suitable materials according to practical situations.

In a specific embodiment, the material of the first low refractive index layer 21 is selected from SiO₂、MgF₂Cryolite and Al₂O₃At least one of (1). The material of the first high refractive index layer 22 is selected from TiO₂、Ta₂O₅、Nb₂O₅OS50 (titanium oxide), ZnS, SiN and HfO₂At least one of (1). The forming process of the material layer formed by the materials is simple, and the compactness of the material layer is good. The filter can further ensure that the filter has higher transmittance to visible light and better cut-off effect to infrared light and the like.

In addition, in order to obtain a better interference effect, the transmittance of the optical filter to other light except red light, blue light and green light is further reduced, meanwhile, the transmittance to the red light, the blue light and the green light is improved, and further, the color gamut effect of the optical filter is improved, wherein the number N of the first low-refractive-index layers is more than or equal to 10; the number M of the first high-refractive-index layers is more than or equal to 10.

In another embodiment of the present application, N is greater than or equal to 20, and M is greater than or equal to 20, so that the color gamut effect of the optical filter is improved by providing more first low refractive index layers and more first high refractive index layers.

In still another embodiment of the present application, the optical filter further includes a second refractive index matching unit 30, as shown in fig. 3 and 4, the second refractive index matching unit 30 is disposed on the second surface, the second refractive index matching unit 30 includes a third refractive index layer and a fourth refractive index layer alternately disposed, and a refractive index of the third refractive index layer is different from a refractive index of the fourth refractive index layer, so that visible light can further have an optical splitting effect with high transmittance and a cut-off infrared region.

In order to further increase the transmittance of the filter for red, green and blue. In one embodiment of the present application, one of the third refractive index layer and the fourth refractive index layer is a second low refractive index layer 31, and the other is a second high refractive index layer 32, and the refractive index of the second low refractive index layer 31 is smaller than the refractive index of the second high refractive index layer 32.

Any one of the above-described first low refractive index layer and first high refractive index layer of the present application may be disposed in contact with the substrate, and a person skilled in the art may select the first low refractive index layer or the first high refractive index layer to be disposed in contact with the substrate according to practical circumstances. Any one of the above-described second low refractive index layer and second high refractive index layer may be disposed in contact with the second surface of the substrate, and a person skilled in the art may select the second low refractive index layer or the second high refractive index layer to be disposed in contact with the second surface of the substrate according to practical circumstances.

In the structure shown in fig. 3, a first high refractive index layer is disposed in contact with the first surface of the substrate, and a second high refractive index layer is disposed in contact with the second surface of the substrate; in the structure of fig. 4, a first low refractive index layer is disposed in contact with the first surface of the substrate, and a second low refractive index layer is disposed in contact with the second surface of the substrate. In an embodiment of the present application, not shown, in contact with the first surface of the substrate is a first low refractive index layer and in contact with the second surface of the substrate is a second high refractive index layer. In another embodiment of the present application, not shown, a first high refractive index layer is provided in contact with the first surface of the substrate, and a second low refractive index layer is provided in contact with the second surface of the substrate.

Similarly, the material of the second low refractive index layer and the material of the second high refractive index layer may be any material having a refractive index satisfying the above requirements and having a small influence on transmittance, and those skilled in the art may select suitable materials according to practical situations.

In a specific embodiment, the material of the second low refractive index layer 21 is selected from SiO₂、MgF₂Cryolite and Al₂O₃At least one of (1). The material of the second high refractive index layer 22 is selected from TiO₂、Ta₂O₅、Nb₂O₅OS50, ZnS, SiN and HfO₂In the above-described embodiments, the material layer is formed by a simple process and has a high density. The filter can further ensure that the filter has higher transmittance to visible light and better cut-off effect to infrared light and the like.

In the present application, each structural layer in the first index matching unit 20 and each structural layer in the second index matching unit 30 may be formed by any suitable method, and a person skilled in the art may select a suitable forming manner according to actual conditions, for example, select a suitable arrangement manner according to specific materials to form corresponding structural layers, for example, a sputtering method, a physical deposition method, a chemical vapor deposition method, a physical vapor deposition method, or an atomic layer deposition method may be used to form corresponding structural layers.

In a specific embodiment of the present application, the arrangement of each structural layer is realized by an ion beam assisted evaporation coating process, which can further improve the compactness of each refractive index layer, improve the uniformity of each refractive index layer, and reduce the refractive index dispersion.

In addition, in order to obtain a better interference effect, the transmittance of the optical filter to other light except red light, blue light and green light is further reduced, meanwhile, the transmittance to the red light, the blue light and the green light is improved, and further, the color gamut effect of the optical filter is improved, wherein the number N of the second low-refractive-index layers is more than or equal to 10; the number M of the second high-refractive-index layers is more than or equal to 10.

In another embodiment of the present application, N is greater than or equal to 20, and M is greater than or equal to 20, so that the color gamut effect of the optical filter is improved by providing more second low refractive index layers and more second high refractive index layers.

In order to ensure that the optical effect of the optical filter is good, and at the same time, ensure that the thickness of the optical filter is small, and meet the requirements of modern electronic equipment for lightness and thinness, in an embodiment of the present application, the thickness of the first refractive index layer and/or the thickness of the second refractive index layer is between 8nm and 300 nm. The thickness further ensures that the manufacturing process of the optical filter is simpler, the manufacturing cost is lower and the optical effect is better.

In still another embodiment of the present application, the thickness of the third refractive index layer and/or the thickness of the fourth refractive index layer is between 8nm and 300 nm. Therefore, the transmittance of the optical filter to red light, blue light and green light can be further improved, and further, the color gamut effect of the optical filter is improved.

Note that the materials and thicknesses of the plurality of first low-refractive-index layers in the first refractive-index matching unit 20 of the present application may be the same or different; the materials and thicknesses of the plurality of first high refractive layers in the first index matching unit 20 may be the same or different; the number and thickness of the materials of the first low refractive layer and the first high refractive index layer may be the same or different. Likewise, the plurality of second low-refractive-index layers in the second index matching unit 20 of the present application may be the same or different, and the plurality of second high-refractive-index layers in the second index matching unit 20 may be the same or different; the number and thickness of the materials of the second low refractive layer and the second high refractive index layer may be the same or different. The total number of material layers in the first refractive index matching unit 20 and the total number of processed layers in the second refractive index layer may be the same or different.

In another exemplary embodiment of the present application, there is provided an electronic device including the optical filter of any one of the above-described optical filters.

The electronic equipment comprises the optical filter, so that the optical effect of the electronic equipment is good, for example, when the electronic equipment is an image pickup equipment, the image pickup equipment has good imaging effect, and image distortion caused by RGB color proportion change can be avoided.

Of course, the electronic apparatus of the present application may be any electronic apparatus including an optical filter, and is not limited to the above-described image pickup apparatus, but may also be a display apparatus or the like.