CN115598901A

CN115598901A - Optical window, optical lens and image acquisition equipment

Info

Publication number: CN115598901A
Application number: CN202111072806.8A
Authority: CN
Inventors: 胡雪松; 曹雨; 陈文华
Original assignee: Huawei Technologies Co Ltd
Current assignee: Huawei Technologies Co Ltd
Priority date: 2021-07-12
Filing date: 2021-09-14
Publication date: 2023-01-13

Abstract

The application discloses optics window, optical lens and image acquisition equipment belongs to optics window defogging defrosting technical field. The optical window comprises a window substrate and a heating antireflection film; the heating antireflection film is positioned on the surface of the window substrate; the heating antireflection film comprises a heating film layer, m first antireflection film layers and n second antireflection film layers; the m first antireflection film layers, the heating film layers and the n second antireflection film layers are sequentially stacked and arranged. Adopt this application, through the heating of heating antireflection coating, make the temperature of optics window higher, can evaporate the ice or frost or the fog of surface, make the surface of optics window keep dry state for during light in the environment fully enters into optical lens, and then improves image acquisition equipment's shooting quality.

Description

Optical window, optical lens and image acquisition equipment

The present application claims priority from chinese patent application No. 202110786379.3 entitled "a heatable optical window glass and camera system" filed on 12.07/2021, the entire contents of which are incorporated herein by reference.

Technical Field

The application relates to the technical field of defogging and defrosting of optical windows, in particular to an optical window, an optical lens and image acquisition equipment.

Background

The optical lens is an essential component of the image acquisition equipment, is a key factor influencing the imaging quality, and mainly comprises a photosensitive device, a lens component and an optical window which are coaxially arranged in sequence, wherein the optical window is positioned at the outermost layer and plays a role in protecting the internal lens component and the photosensitive device.

Because the optical window is located outermost for when external ambient temperature is lower, the surface of optical window freezes easily or frosts, perhaps, humidity in the environment is great, and when the ambient temperature difference is great, the surface of optical window hazes easily. Icing or frosting or fogging of the outer surface of the optical window can reduce the shooting quality of the image acquisition device.

Disclosure of Invention

The application provides an optical window, optical lens and image acquisition equipment, can solve the problem that frosting and hazing are iced easily to the surface of optical window among the correlation technique, technical scheme is as follows:

in one aspect, an optical window is provided, the optical window comprising a window substrate and a heating antireflection film; the heating antireflection film is positioned on the surface of the window substrate, which is vertical to the light inlet direction; the heating antireflection film comprises a heating film layer, m first antireflection film layers and n second antireflection film layers, wherein m and n are positive integers; the m first antireflection film layers, the heating film layers and the n second antireflection film layers are sequentially stacked and arranged.

The surface perpendicular to the light entering direction is also the surface perpendicular to the thickness direction of the window substrate.

In the scheme shown in the application, the heating film layers are sandwiched between the m first antireflection film layers and the n second antireflection film layers, and the two electrodes are positioned on the surfaces of the heating film layers to form the heating antireflection film. After the two electrodes are connected to the circuit and powered on, the heating film layer is a conductive layer, and current flows in the conductive layer to generate heat, so that the heating antireflection film has a heating function. The heating antireflection film is positioned on the surface of the window substrate and can heat the window substrate. The optical window with the heating antireflection film laid on the surface of the window substrate has the advantages that even if the outer surface of the optical window is frozen or frosted or fogged, the temperature of the optical window can be higher through the heating function of the heating antireflection film, so that the ice, frost or fog on the outer surface can be evaporated, the outer surface of the optical window can be kept in a dry state, light in the environment can fully enter an optical lens, the shooting quality of image acquisition equipment is improved, and the definition of shot images is higher.

The heating antireflection film comprises a heating film layer, a first antireflection film layer and a second antireflection film layer, and the heating film layer is located between the first antireflection film layer and the second antireflection film layer. The heating antireflection film with the structure can have higher light transmittance by determining the number, thickness and arrangement mode of the first antireflection film layer and the number, thickness and arrangement mode of the second antireflection film layer through simulation tests. Therefore, the optical window with the heating antireflection film can realize a heating function and ensure higher light transmittance.

In a possible implementation manner, m is greater than or equal to 2, and the materials of the two adjacent first antireflection film layers are different.

In the scheme shown in the application, in order to improve the light transmittance of the heating antireflection film, the number of the first antireflection film layers may be designed to be multiple, the materials of two adjacent first antireflection film layers in the multiple first antireflection film layers are different, and the materials are different in order to make the refractive indexes of the two adjacent first antireflection film layers different. The effect of reducing the reflectivity and improving the light transmittance can be achieved by designing the arrangement mode of the film layers with different refractive indexes.

In a possible implementation manner, n is greater than or equal to 2, and the materials of the two adjacent second antireflection film layers are different.

In the scheme shown in the application, in order to improve the light transmittance of the heating antireflection film, the number of the second antireflection film layers may be designed to be multiple, and the materials of two adjacent second antireflection film layers in the multiple second antireflection film layers are different, where the materials are different so as to make the refractive indexes of the two adjacent second antireflection film layers different. The effect of reducing the reflectivity and improving the light transmittance can be achieved by designing the arrangement mode of the film layers with different refractive indexes.

In one possible implementation manner, the material of each first antireflection film layer and the material of each second antireflection film layer are any one of silicon dioxide, titanium dioxide, magnesium fluoride, tantalum pentoxide, niobium pentoxide, and aluminum oxide.

In a possible implementation manner, the material of the heating film layer is indium tin oxide ITO.

According to the scheme, the indium tin oxide is a transparent conductive material with excellent performance, and can improve the heating efficiency, reduce the reflection and increase the transmission when being used as a heating film layer.

In one possible implementation, the thicknesses of the heating film layer, each first antireflection film layer, and each second antireflection film layer are all between 5nm and 250 nm.

In one possible implementation, the heating antireflection film further comprises two electrodes; each electrode is positioned on the surface of the heating film layer, which is opposite to the window substrate, and on the side of an optical view field region of the optical window, wherein the optical view field region is a region of the optical window for light to penetrate through.

The electrode may be a conductive tape, or a structure with a conductive tape on the surface, or a structure with conductive glue coated on the surface, etc.

The surface of the heating film layer facing away from the window substrate may also be referred to as a surface of the heating film layer away from the window substrate.

In one example, a surface of the heating film layer facing away from the window substrate is positioned opposite a surface of the heating film layer facing the window substrate. For example, the heating antireflection film is located on a surface of the window substrate, and then one surface (e.g., the lower surface) of the heating film layer in the heating antireflection film faces the window substrate, and the other surface (e.g., the upper surface) faces away from the window substrate, which is the surface of the heating film layer facing away from the window substrate.

The scheme that this application shows, two electrodes are one as anodal, and another is as the negative pole, adds voltage to two electrodes like this, heating rete in alright have the electric current to pass through, and the production of heat, heat transfer to whole optics window, and then for the heating of optics window.

In one possible implementation, one of the two electrodes is located on a first side of the optical field region and the other is located on a second side of the optical field region, the first and second sides of the optical field region being oppositely located.

The scheme that this application shows, because light is the optics visual field area entering optical lens through the optics window, then, for the heating of optics window, mainly the optics visual field area heating of optics window.

After the two electrodes are connected into the circuit, the current for heating the film layer flows between the two electrodes, so that in order to improve the heating effect, the two electrodes can be located on two sides of the optical view field region of the optical window, that is, one of the two electrodes is located on a first side of the optical view field region, the other electrode is located on a second side of the optical view field region, and the first side and the second side of the optical view field region are opposite. In this way, the current flowing in the heating film layer crosses the optical field region, and the efficiency of heating the optical field region can be improved.

In a possible implementation, the surface of the heating film layer facing away from the window substrate has an exposed area on a side of the optical view field region, and the electrode is electrically connected to the heating film layer through the exposed area.

In the scheme shown in the application, the exposed area of the surface of the heating film layer, which is opposite to the window substrate, is the area of the surface of the heating film layer, which is opposite to the window substrate, which is not covered by the second antireflection film layer. Through the exposed area, the electrode can be electrically connected with the heating film layer.

In one possible implementation manner, the n second antireflection film layers are far away from the window substrate relative to the m first antireflection film layers; the second antireflection film layer is provided with notches on the side portions of the optical visual field region to form the exposed region. Optionally, in an embodiment, the positions of the notches of the n second antireflection film layers may be aligned.

According to the scheme, each second antireflection film layer is provided with a notch at the side of the optical viewing field area, after the second antireflection film layers are superposed on the surface of the heating film layer, the notches of the second antireflection film layers are opposite, the notches penetrate through the heating film layer and expose the surface of the heating film layer, and the electrodes are located in the penetrating notches and are in contact with the surface of the heating film layer, so that voltage is applied to two ends of the heating film layer, and the heating function is realized.

The exposed area is formed by forming the notch on the second anti-reflection film layer, so that the areas of the first anti-reflection film layer and the heating film layer are not required to be too large, the space can be saved, and the miniaturization development of the optical window is facilitated.

In one possible implementation manner, the n second antireflection film layers are far away from the window substrate relative to the m first antireflection film layers; the area of the second antireflection film layer is smaller than that of the heating film layer, so that the exposed area is formed. Optionally, in this embodiment, the positions of the n second antireflection film layers may be aligned.

In the embodiments shown herein, the area of the second antireflective film layer is smaller than the area of the heating film layer, for example, the width of the second antireflective film layer is smaller than the width of the heating film layer, or the length of the second antireflective film layer is smaller than the length of the heating film layer, or both the width and the length of the second antireflective film layer are smaller than the width and the length of the heating film layer. Thus, after the plurality of second antireflection film layers are superposed on the surface of the heating film layer, which is back to the window substrate, a part of the surface of the heating film layer, which is back to the window substrate, is exposed, so that the electrodes and the heating film layer can be formed.

The exposed area is formed through the size, a gap does not need to be processed on the second antireflection film layer, and the processing efficiency can be improved in the aspect of processing.

In one possible implementation manner, the optical window further comprises an optical antireflection film; the optical antireflection film is positioned on the surface of the window substrate, which is opposite to the heating antireflection film; the optical antireflection film comprises at least one third antireflection film layer, and the at least one third antireflection film layer is arranged in a stacked mode.

In the scheme shown in the application, the optical window comprises a window substrate, a heating antireflection film and an optical antireflection film, wherein the heating antireflection film is positioned on the inner surface of the window substrate, and the optical antireflection film is positioned on the outer surface of the window substrate. The heating antireflection film is used for heating and antireflection of the optical window, and the optical antireflection film is used for antireflection of the optical window. Thus, the optical window has a heating function and high light transmittance.

In a possible implementation manner, the material of each third antireflection film layer is any one of silicon dioxide, titanium dioxide, magnesium fluoride, tantalum pentoxide, niobium pentoxide, and aluminum oxide.

In one possible implementation, the material of the window substrate is any one of glass, optical resin and polycarbonate.

In another aspect, an optical lens is provided, where the optical lens includes a lens assembly and the optical window described above, the optical window is located at an outermost layer of the optical lens, and the heating antireflection film is close to the lens assembly relative to the window substrate.

According to the scheme, the optical window of the optical lens comprises the heating antireflection film, the heating antireflection film is laid on the inner surface of the window substrate, the heating antireflection film has a heating function, even if the outer surface of the optical window is frozen or frosted or fogged, the temperature of the optical window is high by heating the heating antireflection film, the ice or frost or fog on the outer surface can be evaporated, the outer surface of the optical window is kept in a dry state, light in the environment fully enters the optical lens, the shooting quality of image acquisition equipment is improved, and the definition of shot images is high.

The heating antireflection film comprises a heating film layer, a first antireflection film layer and a second antireflection film layer, and the heating film layer is located between the first antireflection film layer and the second antireflection film layer. The heating antireflection film with the structure can be enabled to have higher light transmittance by determining the number, the thickness and the arrangement mode of the first antireflection film layer and the number, the thickness and the arrangement mode of the second antireflection film layer through simulation tests. Therefore, the optical window with the heating antireflection film can realize a heating function and ensure higher light transmittance.

In another aspect, an image capturing apparatus is provided, where the image capturing apparatus includes a light sensing device, an image signal processor ISP, and the optical lens described above; the photosensitive device is used for performing photoelectric conversion on an optical signal passing through the optical lens to generate an original image; and the ISP is used for carrying out image processing on the original image.

The scheme shown in the application, this image acquisition equipment's optical lens include the aforesaid optical window, as described above, this optical window is including heating the antireflection coating, the internal surface at the window basement is laid to the heating antireflection coating, the heating antireflection coating has the heating function, even then the surface of optical window freezes or frosts or hazes, through the heating of heating the antireflection coating, make the temperature of optical window higher, can evaporate the ice or the frost or the fog of surface, make the surface of optical window keep dry state, make the light in the environment fully enter into optical lens, and then improve image acquisition equipment's shooting quality, make the definition of the image of shooing higher.

Furthermore, the heating antireflection film includes a heating film layer, a first antireflection film layer, and a second antireflection film layer, and the heating film layer is located between the first antireflection film layer and the second antireflection film layer. The heating antireflection film with the structure can have higher light transmittance by determining the number, thickness and arrangement mode of the first antireflection film layer and the number, thickness and arrangement mode of the second antireflection film layer through simulation tests. Therefore, the optical window with the heating antireflection film can realize a heating function and ensure higher light transmittance.

Drawings

Fig. 1 is a schematic structural diagram of an optical system of an image capturing device provided in the present application;

FIG. 2 is an exploded view of an optical window according to the present disclosure;

FIG. 3 is a schematic view of an optical window according to the present disclosure;

FIG. 4 is a schematic view of an optical window according to the present disclosure;

FIG. 5 is a schematic view of a heating film layer of an optical window provided in the present application;

FIG. 6 is a schematic view of an optical window according to the present disclosure;

FIG. 7 is a schematic view of an optical window according to the present disclosure;

FIG. 8 is a schematic view of an optical window according to the present disclosure;

FIG. 9 is a schematic view of a heating film layer of an optical window provided in the present application;

FIG. 10 is a schematic view of an optical window according to the present disclosure;

FIG. 11 is a schematic view of an optical window according to the present disclosure;

FIG. 12 is a schematic diagram of a spectrum curve obtained from a simulation test performed on a heating antireflection film provided in the present application.

Description of the figures

1. A window substrate;

2. heating the antireflection film; 21. heating the film layer; 211. an exposed area;

22. a first anti-reflection film layer; 23. a second anti-reflection film layer; 24. an electrode;

3. an optical view field region;

4. an optical antireflection film; 41. a third anti-reflection film layer;

100. a light sensing device; 200. an optical lens; 201. a lens assembly; 202. an optical window.

Detailed Description

The embodiment of the application provides an optical window, which is an important component of an optical lens, and the optical lens is an important component of an image acquisition device, as shown in fig. 1, which is a structural schematic diagram of an optical system of the image acquisition device, the optical system mainly includes a photosensitive device 100 and an optical lens 200, wherein the optical lens 200 mainly includes a lens assembly 201 and an optical window 202, as shown in fig. 1, the photosensitive device 100, the lens assembly 201, and the optical window 202 are sequentially coaxially arranged from inside to outside, and the optical window 202 is located at the outermost layer, thereby playing a role in protecting the photosensitive device 100 and the lens assembly 201.

The coaxial arrangement means that central axes of the photosensitive device 100, the lens assembly 201 and the optical window 202 are in a straight line, so that light rays passing through the optical window 202 can better pass through the lens assembly 201, be transmitted to the photosensitive device 100, and be received by the photosensitive device 100.

The light sensing device 100 serves as a core element of the optical lens, and is configured to perform photoelectric conversion on an optical signal passing through the optical lens 200 to generate an original image. The photosensitive device 100 may be a Charge Coupled Device (CCD) image sensor or a complementary metal-oxide semiconductor (CMOS) image sensor. The present application does not limit the specific structure of the photosensitive device 100.

The optical system of the image capturing apparatus further includes an Image Signal Processing (ISP), where the ISP is electrically connected to the photosensitive device 100, and the ISP is used to perform image processing on the original image generated by the photosensitive device 100.

As shown in fig. 1, the lens assembly 201 is an assembly that combines optical mirrors (e.g., mirrors, transmission mirrors, prisms, etc.) of various shapes and different media (e.g., plastic, glass, crystal, etc.) in a certain manner. The lens assembly 201 is used to make the light passing through these optical mirrors change the transmission direction of the light according to the needs of people and then be received by the light sensing device 100, so as to complete the optical imaging of the object.

Since the optical window 202 is used as an optical lens protection member and located at the outermost layer of the optical lens, light needs to be incident on the lens assembly 201 through the optical window 202, and therefore the optical window 202 needs to have a high light transmittance to improve the imaging quality of the optical lens.

As shown in fig. 1, the optical window 202 may include a window substrate 1 having light transmittance, the material of the window substrate 1 may be glass, optical resin, or polycarbonate, and the material of the window substrate 1 is not limited in this embodiment, and can satisfy a high light transmittance.

In general, in order to further improve the light transmittance of the optical window 202, the surface of the window substrate 1 is plated with an anti-reflection film layer, for example, the inner surface of the window substrate 1 is plated with an anti-reflection film layer, or the outer surface of the window substrate 1 is plated with an anti-reflection film layer, or both the inner surface and the outer surface of the window substrate 1 are plated with an anti-reflection film layer, so as to improve the light transmittance of the optical window. The inner surface of the window substrate 1 is a surface close to the lens assembly 201, and the outer surface and the inner surface of the window substrate 1 are opposite to each other. The antireflection film layer may also be referred to as an anti-reflection (AR) film layer, and mainly reduces reflected light to increase transmitted light. The first antireflection film layer, the second antireflection film layer and the third antireflection film layer, which are introduced below, all belong to the above antireflection film layers.

Because the optical window is located at the outermost layer of the optical lens, the optical window is exposed to the environment and is easily affected by the environment when the image acquisition device is in operation. For example, if the ambient temperature is low and the humidity is low, the outer surface of the optical window is prone to frost or ice formation, and for example, if the ambient temperature changes abruptly, the outer surface of the optical window may also be fogged. Icing or frosting or fogging of the outer surface of the optical window can reduce the light entering amount of the optical lens, thereby reducing the imaging quality of the optical lens.

In order to solve the problem of icing or fogging on the outer surface of the optical window, a heating wire may be disposed on the optical window to heat the optical window. In order not to affect the amount of light entering the optical window, the heating wire is usually located near the edge of the optical window. However, the heating wire is located at the edge of the optical window, the central area of the optical window needs to be gradually heated by heat transfer, and the thermal conductivity of the optical window is poor, which results in low efficiency of heating the optical window.

In order to improve the heating efficiency, a heating film layer with light transmittance may be laid on the surface of the optical window. For example, the surface of the window substrate 1 is plated with a heating film layer, or the surface of the window substrate 1 is plated with an antireflection film layer first, and then the surface of the antireflection film layer is plated with a heating film layer, but in any way, the heating film layer is the outermost film layer of the optical window. Although the optical window can improve the heating efficiency, the refractive index of the heating film layer is usually relatively high (the refractive index of the heating film layer made of indium tin oxide is about 2.0), and the heating film layer is arranged on the outermost layer of the optical window, so that the light transmittance of the optical window is relatively low. Through simulation tests on the optical window, the light transmittance of the optical window is only about 80%, and the light transmittance of the optical window without the heating film layer is about 97%. Therefore, the heating film layer is positioned on the outermost optical window, so that the heating efficiency is improved, but the light transmittance is sacrificed, the imaging quality of the image acquisition equipment is still poor, and the definition of the acquired image is low.

Moreover, the heating film layer is positioned at the outermost layer of the optical window, the heating film layer is in direct contact with the environment, the time is long, and the heating film layer is easy to oxidize and deliquesce, so that the heating of the optical window is influenced.

The optical window disclosed by the application can improve the heating efficiency of the optical window under the condition of not sacrificing or slightly sacrificing the light transmittance of the optical window.

As shown in fig. 2, which is a schematic view of an explosion structure of an optical window in the present application, the optical window includes a window substrate 1 and a heating antireflection film 2, and the heating antireflection film 2 is located on a surface of the window substrate 1 perpendicular to a light entering direction.

The surface perpendicular to the light entering direction is a surface perpendicular to the thickness direction of the window substrate 1.

In one example, as shown in fig. 1, the surface of the window substrate 1 perpendicular to the light entering direction includes two surfaces, which are located opposite to each other, and when the optical lens is assembled in the later period, one of the two surfaces constitutes an inner surface of the window substrate 1 (i.e., a surface located inside the optical lens and also a surface facing the lens assembly 201), and the other constitutes an outer surface of the window substrate 1 (i.e., a surface located outside the optical lens).

As shown in fig. 1, the heating antireflection film 2 may be located on the inner surface of the window substrate 1, because the heating antireflection film 2 needs to be energized to heat, and if the heating antireflection film 2 is located on the outer surface of the window substrate 1, since the heating antireflection film 2 is exposed to the outside and a conductive failure easily occurs, the heating antireflection film 2 may be located on the inner surface of the window substrate 1 in order to ensure the energization stability of the heating antireflection film 2. Of course, the heating antireflection film 2 may be disposed on the outer surface of the window substrate 1, for example, the heating antireflection film 2 may be disposed on both the inner surface and the outer surface of the window substrate 1. In this embodiment, whether the heating antireflection film 2 is on the inner surface or the outer surface of the window substrate 1 is not particularly limited, and the heating antireflection film 2 may be located on the inner surface of the window substrate 1.

Wherein, the heating antireflection film 2 is a film layer with heating function and antireflection function.

As shown in fig. 2, heating antireflection film 2 includes heating film layer 21, m first antireflection film layers 22, and n second antireflection film layers 23, and as shown in fig. 3, m first antireflection film layers 22, heating film layers 21, and n second antireflection film layers 23 are stacked in this order, so that heating film layer 21 may be located between m first antireflection film layers 22 and n second antireflection film layers 23. Wherein m and n are both positive integers.

The heating film layer 21 may be any film layer that has optical transparency and generates heat when energized, and for example, the material of the heating film layer 21 may be indium-tin oxide (ITO). The heating film layer 21 is heated by energization, and thus may be referred to as a conductive film layer.

The first antireflection film layer 22 and the second antireflection film layer 23 may be any film layers having antireflection and transmittance increasing properties, and the sum of the reflectance and the transmittance of the film layers is 1 when the absorptivity of the film layers is neglected, so that the transmittance can be increased by reducing the reflection.

The materials of first antireflection film layer 22 and second antireflection film layer 23 are described below. The first anti-reflection film layer 22 and the second anti-reflection film layer 23 may be the same or different in material, and are different from each other in that they are located on different sides of the heating film layer 21.

In one example, the material of first antireflection film layer 22 may be any one of silicon dioxide, titanium dioxide, magnesium fluoride, tantalum pentoxide, niobium pentoxide, and aluminum oxide. The material of second antireflection film layer 23 may also be any one of silicon dioxide, titanium dioxide, magnesium fluoride, tantalum pentoxide, niobium pentoxide, and aluminum oxide.

As described above, the number of first antireflection film layers 22 is m, the number of second antireflection film layers 23 is n, and m and n are positive integers. Then, the number of first antireflection film layers 22 may be one or more, and the number of second antireflection film layers 23 may be one or more.

As shown in FIG. 2 with reference to FIG. 3, each of first antireflection film layer 22 and second antireflection film layer 23 may be one, and heating film layer 21 may be sandwiched between first antireflection film layer 22 and second antireflection film layer 23.

As shown in fig. 4, the number of the first antireflection film layers 22 is multiple, and the number of the second antireflection film layers 23 is also multiple, where the number of the first antireflection film layers 22 and the number of the second antireflection film layers 23 may be equal or not. Heating film layer 21 is sandwiched between all first antireflection film layers 22 and all second antireflection film layers 23.

In other examples, the number of first antireflection film layers 22 is one, the number of second antireflection film layers 23 is plural, and the heating film layer 21 is sandwiched between one first antireflection film layer 22 and plural second antireflection film layers 23. Alternatively, the number of first antireflection film layers 22 may be plural, the number of second antireflection film layers 23 may be one, and heating film layer 21 may be sandwiched between plural first antireflection film layers 22 and one second antireflection film layer 23.

In one example, if the number of first antireflection film layers 22 is multiple, the materials of two adjacent first antireflection film layers 22 in the multiple first antireflection film layers 22 are different. The material difference is to make the refractive indexes of two adjacent first antireflection film layers 22 different. The effect of reducing the reflectivity of the heating antireflection film 2 and improving the light transmittance can be achieved by designing the arrangement mode of the film layers with different refractive indexes.

For example, the material of the first antireflection film layers 22 includes two materials, and the first antireflection film layers 22 of the two materials are alternately stacked. For another example, the material of the first antireflection film layers 22 includes two or more materials, and the first antireflection film layers 22 of the multiple materials are alternately stacked. In this embodiment, the arrangement manner of the first antireflection film layers 22 is not limited, and it is sufficient that the materials of two adjacent first antireflection film layers 22 are different.

Similarly, if there are a plurality of second antireflection film layers 23, the materials of two adjacent second antireflection film layers 23 in the plurality of second antireflection film layers 23 are different. The material is different so that the refractive indexes of two adjacent second antireflection film layers 23 are different. The effect of reducing the reflectivity of the heating antireflection film 2 and improving the light transmittance can be achieved by designing the arrangement mode of the film layers with different refractive indexes.

For example, the second antireflection film layers 23 include two materials, and the second antireflection film layers 23 made of the two materials are alternately stacked. For another example, the materials of the second antireflection film layers 23 include two or more materials, and the second antireflection film layers 23 of the multiple materials are alternately stacked. In this embodiment, the arrangement manner of the second antireflection film layers 23 is not limited, and it is sufficient that the materials of two adjacent second antireflection film layers 23 are different.

Regarding the positional relationship between the m first antireflection film layers 22 and the n second antireflection film layers 23, respectively, and the window substrate 1, as described above, the heating antireflection film 2 is located on the surface of the window substrate 1, and then the first antireflection film layer 22 may be located next to the window substrate 1. Thus, m first antireflection film layers 22 are stacked on the surface of the window substrate 1, the heating film layers 21 are disposed on the surfaces of the m first antireflection film layers 22, and the n second antireflection film layers 23 are stacked on the surfaces of the heating film layers 21.

Of course, the second antireflection film layer 23 may be located on the surface of the window substrate 1, such that n second antireflection film layers 23 are stacked on the surface of the window substrate 1, the heating film layer 21 is located on the surfaces of the n second antireflection film layers 23, and the m first antireflection film layers 22 are stacked on the surfaces of the heating film layers 21.

In this embodiment, it is not limited that the first antireflection film layer 22 is adjacent to the window substrate 1, and the second antireflection film layer 23 is adjacent to the window substrate 1, and the first antireflection film layer 22 is adjacent to the window substrate 1 as shown in fig. 3. In this embodiment, the antireflection film layer between the window substrate 1 and the heating film layer 21 is referred to as a first antireflection film layer 22, and the antireflection film layer on the side of the heating film layer 21 opposite to the window substrate 1 is referred to as a second antireflection film layer 23.

Thus, at least one first antireflection film layer 22, heating film layers 21, and at least one second antireflection film layer 23 are stacked in this order, and heating film layers 21 are located between all first antireflection film layers 22 and all second antireflection film layers 23. It can be seen that the heating film layer 21 with the higher refractive index is located inside the heating antireflection film 2, but not on the outermost layer, and then simulation tests are performed to design the first antireflection film layer and the second antireflection film layer on the two sides of the heating film layer 21 (including the number of the film layers, the film layer arrangement, the film layer thickness, and the like), so that the light transmittance of the heating antireflection film 2 can meet the requirement, for example, the light transmittance of the heating antireflection film 2 can reach more than 96%.

The number of the first antireflection film layers 22, the number of the second antireflection film layers 23, and the arrangement manner among the heating film layer 21, the first antireflection film layer 22, and the second antireflection film layer 23 may be determined through simulation tests. For example, in a simulation test, the number of the first antireflection film layers 22, the number of the second antireflection film layers 23, and the arrangement manner among the heating film layers 21, the first antireflection film layers 22, and the second antireflection film layers 23 may be adjusted according to the reflectivity or the light transmittance of the heating antireflection film 2. Wherein, under the condition of neglecting the absorptivity of the heating antireflection film 2, the sum of the reflectivity and the light transmittance of the heating antireflection film 2 is 1.

The thicknesses of the heating film layer 21, the first antireflection film layer 22, and the second antireflection film layer 23 may also be determined through simulation tests, for example, the thicknesses of the three layers may be 5nm to 250nm, and regarding the specific thickness of the heating film layer 21, the specific thickness is also related to the heating power of the heating film layer 21, the size of the heating film layer 21, and the resistivity of the heating film layer 21, for example, the thickness of the heating film layer 21 may be calculated as follows.

Wherein, the heating power of the heating film 21 can be about 3W, the supplied voltage can be 12V, and then, according to the formula

In the formula, P represents power, U represents voltage, and R represents resistance, and it is understood that the resistance R of the heating film layer 21 is about 48 Ω.

According to the formula

Where ρ is the resistivity of the heating film layer 21, and if the material of the heating film layer 21 is ITO, it may be 5 × 10 ^-4 Omega/cm to 5X 10 ^-5 Taking values between omega/cm; l is ₁ To heat the length of the conductive region of the film layer 21, see fig. 5; l is a radical of an alcohol ₂ For the width of the conductive region, see FIG. 5, where L ₁ And L ₂ May be taken to be equal; d is the thickness of the heating film layer 21, as can be seen in fig. 5. Then, if ρ is 5 × 10 ^-4 Omega/cm, R is 48 omega, and the thickness d of the heating film layer 21 can be calculated to be 104.1nm. The thickness of the heating film 21 can be calculated according to the above-mentioned method, and in practical applications, the actual thickness of the heating film 21 is slightly different from the calculated thickness due to the influence of the processing process.

In order to allow current to pass through the heating film layer 21, two electrodes are required to be added to the heating film layer 21, and accordingly, as shown in fig. 6, the heating antireflection film 2 further includes two electrodes 24, where one of the two electrodes 24 serves as a positive electrode and the other serves as a negative electrode.

The electrode 24 may be a conductive tape, or a structure having a conductive tape on the surface, or a structure having a conductive glue on the surface, etc.

Since the electrodes 24 are used to apply voltage to the heating film 21, the electrodes 24 need to be in contact with the heating film 21, or the electrodes 24 need to be in contact with the heating film 21 through conductive glue, as shown in fig. 7, each electrode 24 is located on the surface of the heating film 21.

For example, the electrode 24 is located on the surface of the heating film layer 21 facing away from the window substrate 1. The surface of the heating film layer 21 facing away from the window substrate 1 is opposite to the surface of the heating film layer 21 facing the window substrate 1. The surface of the heating film layer 21 facing the window substrate 1 may be referred to as a surface of the heating film layer 21 close to the window substrate 1, and the surface of the heating film layer 21 facing away from the window substrate 1 may be referred to as a surface of the heating film layer 21 away from the window substrate 1.

For example, referring to fig. 1 and 2, the heating antireflection film 2 is located on the surface of the window substrate 1, and the first antireflection film layer 22, the heating film layer 21, and the second antireflection film layer 23 of the heating antireflection film 2 are sequentially stacked from bottom to top, so that one surface (e.g., the lower surface) of the heating film layer 21 faces the window substrate 1, and the other surface (e.g., the upper surface) of the heating film layer 21 faces away from the window substrate 1. Then, the surface of the heating film layer 21 facing away from the window substrate 1 is the upper surface of the heating film layer 21 shown in fig. 1.

The electrode 24 is located on the surface of the heating film 21 opposite to the window substrate 1 because: the thickness of the electrode 24 is usually much greater than the thickness of the first antireflection film layer 22 and the second antireflection film layer 23, and if the electrode 24 is located on the surface of the heating film layer 21 close to the window substrate 1 and the total thickness of the first antireflection film layers 22 located between the heating film layer 21 and the window substrate 1 is smaller than the thickness of the electrode 24, an air layer will exist between the window substrate 1 and the first antireflection film layers 22, and the heating film layer 21 cannot heat the window substrate 1. Therefore, the electrode 24 is located on the surface of the heating film layer 21 facing away from the window substrate 1.

Since the electrodes 24 do not have light transmittance, in order to avoid the electrodes 24 blocking light, correspondingly, as shown in fig. 7, the two electrodes 24 are both on the side of the optical view field region 3 of the optical window, wherein the optical view field region 3 is also the region of the optical window for light to pass through, for example, as shown in fig. 7, it may be a region centered at the center of the optical window.

Thus, as shown in fig. 7, each of the two electrodes 24 is located on the surface of the heating film layer 21 facing away from the window substrate 1 and on the side of the optical view field region 3 of the optical window.

In order to realize that the electrode 24 is located on the surface of the heating film layer 21 facing away from the window substrate 1, accordingly, as shown in fig. 6, the surface of the heating film layer 21 facing away from the window substrate 1 has an exposed region 211 at the side of the optical view field region 3, and the electrode 24 can be electrically connected to the heating film layer 21 through the exposed region 211.

The exposed region 211 is a region of the surface of the heating film layer 21 facing away from the window substrate 1 and not covered by the n second antireflection film layers 23.

The exposed region 211 includes a plurality of formations, two of which are described below.

(first mode), the exposed region 211 may be formed by, as shown in fig. 6, forming a gap 231 in the antireflection film layer on the first side of the heating film layer 21, where the first side of the heating film layer 21 is the side opposite to the window substrate 1. For example, as shown in fig. 6, n second antireflection film layers 23 are away from the window substrate 1 relative to m first antireflection film layers 22, each second antireflection film layer 23 has a notch 231 on a side of the optical field region 3, and optionally, the notches 231 of the n second antireflection film layers 23 are aligned to form an exposed region 211.

In the manner of forming the exposed region 211 by forming the notch 231 on the side of the second antireflection film layer 23, the manner of electrically connecting the electrode 24 and the heating film layer 21 may at least include the following manner.

For example, as shown in fig. 6 and with reference to fig. 7, the size and shape of both the gap 231 and the electrode 24 are matched such that the electrode 24 can be positioned in the gap 231 to achieve electrical connection of the electrode 24 and the heating film layer 21.

For another example, the size of the electrode 24 is larger than that of the notch 231, for example, the length and the width of the electrode 24 are both larger than those of the notch 231, the electrode 24 is located on the outer surface of the outermost second antireflection film layer 23 and covers the notch 231, and since the thickness of the second antireflection film layer 23 is thinner and is in the nanometer order, the height of the notch 231 is smaller, and conduction between the electrode 24 and the heating film layer 21 can also be achieved. Alternatively, the electrode 24 and the heating film layer 21 are coated with a conductive paste at a position corresponding to the notch 231, and the electrical connection is achieved through the conductive paste.

In this embodiment, the dimensional relationship between the electrode 24 and the gap 231 is not limited, and the electrode 24 and the heating film layer 21 may be electrically connected by exposing the heating film layer 21 through the gap 231.

In this way, each second antireflection film layer 23 has a notch 231 on the side of the optical viewing field region 3, as shown in fig. 6, after the plurality of second antireflection film layers 23 are stacked on the surface of the heating film layer 21, the positions of the notches 231 of the plurality of second antireflection film layers 23 are aligned, that is, the notches 231 penetrate through to expose the surface of the heating film layer 21, and the electrode 24 is electrically connected to the heating film layer 21 through the penetrating notches 231, wherein the exposed part of the heating film layer 21 can be referred to as an exposed region 211.

The exposed region 211 is formed by forming the notch 231 in the second antireflection film layer 23, so that the areas of the first antireflection film layer 22 and the heating film layer 21 do not need to be too large, the space can be saved, and the miniaturization development of the optical window is facilitated.

(manner two), another implementation manner of the exposed region 211 may also be that, as shown in fig. 8, the area of the antireflection film layer on the first side of the heating film layer 21 is smaller than the area of the heating film layer 21, and the first side of the heating film layer 21 is the side facing away from the window substrate 1. For example, as shown in fig. 8, n second antireflection film layers 23 are away from the window substrate 1 with respect to m first antireflection film layers 22, the area of each second antireflection film layer 23 is smaller than that of the heating film layer 21, and the n second antireflection film layers 23 are aligned to form the exposed region 211.

As an example, the width of second antireflection film layer 23 may be less than the width of heating film layer 21, or the length of second antireflection film layer 23 may be less than the length of heating film layer 21, or, as shown in FIG. 8, both the width and the length of second antireflection film layer 23 may be less than the width and the length of heating film layer 21. Thus, as shown in fig. 8, after the plurality of second antireflection film layers 23 are stacked on the surface of the heating film layer 21 opposite to the window substrate 1, a part of the surface of the heating film layer 21 opposite to the surface of the window substrate 1 is exposed, so that the electrodes 24 and the heating film layer 21 can be connected.

In the manner of forming the exposed region 211 by using the second antireflection film layer 23 having an area smaller than that of the heating film layer 21, the manner of electrically connecting the electrode 24 and the heating film layer 21 may at least include the following manner.

For example, as shown in fig. 8 and with reference to fig. 9, the electrode 24 is disposed on the exposed region 211, and the electrode 24 and the heating film layer 21 are electrically connected. For another example, the size of the electrode 24 is larger than that of the exposed region 211, the electrode 24 is located on the outer surface of the outermost second antireflection film layer 23 and covers the exposed region 211, and since the thickness of the second antireflection film layer 23 is thinner and is in the nanometer level, the distance between the exposed region 211 and the outermost second antireflection film layer 23 is smaller, and conduction between the electrode 24 and the heating film layer 21 can also be achieved. Alternatively, the electrode 24 and the heating film layer 21 are coated with a conductive adhesive at a position corresponding to the exposed region 211, and electrical connection is achieved through the conductive adhesive.

The exposed region 211 is formed by the dimension, and the notch 231 does not need to be processed on the second antireflection film layer 23, so that the processing efficiency can be improved in processing.

The present embodiment does not limit how to form the exposed region 211, and how to electrically connect the electrode 24 and the heating film 21, and can be flexibly designed according to actual situations.

Since the light enters the optical lens through the optical view field region 3 of the optical window, the optical window is heated, mainly the optical view field region 3 of the optical window.

And the current for heating the film layer 21 flows between the two electrodes 24 after the two electrodes 24 are connected into the circuit, then, in order to improve the heating effect, as shown in fig. 7, the two electrodes 24 may be located at both sides of the optical view field region 3 of the optical window, that is, one electrode 24 of the two electrodes 24 is located at the first side of the optical view field region 3, the other electrode 24 is located at the second side of the optical view field region 3, and the first side and the second side of the optical view field region 3 are opposite. In this way, the current flowing in the heating film layer 21 crosses the optical view field region 3, and the efficiency of heating the optical view field region 3 can be improved.

Based on the above, this optical window includes the heating antireflection coating, and the heating antireflection coating has the heating function, even the surface of optical window freezes or frosts or hazes, through the heating of heating antireflection coating, makes the temperature of optical window higher, can evaporate the ice or frost or the fog of surface, makes the surface of optical window keep dry state for light in the environment fully enters into optical lens, and then improves image acquisition equipment's shooting quality, makes the definition of the image of shooing higher.

Moreover, because the heating antireflection film 2 is laid on the surface of the window substrate 1, the whole surface of the window substrate 1, especially the surface of the whole optical view field region 3, can be directly heated, so that the heating efficiency is improved, and the optical window can be rapidly deiced, defrosted and demisted.

Since the heating film layer 21 in the heating antireflection film 2 is located inside the heating antireflection film 2, not at the outermost layer, high light transmittance of the heating antireflection film 2 can be achieved. After the heating antireflection film 2 is located on the inner surface of the window substrate 1, the heating film layer 21 is not in contact with the inner surface of the window substrate 1, nor is located on the outermost layer of the optical window. The optical window with the heating antireflection film 2 can realize a heating function and ensure higher light transmittance. In addition, because the heating film layer 21 is located inside and isolated from the ambient air, the oxidation and deliquescence of the heating film layer 21 can be avoided, and the service life of the heating film layer can be prolonged.

As described above, the optical window needs to have a heating function and also needs to satisfy a requirement of high light transmittance, and in order to further improve the light transmittance, as shown in fig. 10, the optical window further includes an optical antireflection film 4. Wherein, the optical anti-reflection film 4 is a film layer with the functions of reducing reflection and increasing transmission. The optical antireflection film 4 is located on a surface of the window substrate 1 opposite to the heating antireflection film 2, that is, the heating antireflection film 2 and the optical antireflection film 4 are respectively located on two opposite surfaces of the window substrate 1, and the two surfaces are perpendicular to the light entering direction. For example, referring to fig. 1, the heating antireflection film 2 is disposed on an inner surface of the window substrate 1, and the optical antireflection film 4 is disposed on an outer surface of the window substrate 1, where the inner surface of the window substrate 1 is a surface facing the lens assembly 201, and the outer surface of the window substrate 1 is a surface facing away from the lens assembly 201 and is a surface exposed outside the optical lens.

As described above, heating antireflection film 2 includes heating film layer 21, first antireflection film layer 22, and second antireflection film layer 23 because it has heating and antireflection functions, and optical antireflection film 4 includes third antireflection film layer 41 because it has antireflection functions. Third antireflection coating layer 41, first antireflection coating layer 22, and second antireflection coating layer 23 function in the same manner, and both functions are to increase light transmittance. Correspondingly, the number of the third antireflection film layers 41 may be one or more, and the material may be any one of silicon dioxide, titanium dioxide, magnesium fluoride, tantalum pentoxide, niobium pentoxide, and aluminum oxide, and the thickness may be 5nm to 250 nm.

In one example, the number of the third antireflection film layer 41 may be one, and then the third antireflection film layer 41 is located on the surface of the window substrate 1 opposite to the heating antireflection film 2.

As shown in fig. 10, the number of the third antireflection film layers 41 may be multiple, multiple third antireflection film layers 41 are stacked on the surface of the window substrate 1 opposite to the heating antireflection film 2, and the materials of two adjacent third antireflection film layers 41 in the multiple third antireflection film layers 41 are different.

For example, the materials of the third antireflection film layers 41 include two materials, and the third antireflection film layers 41 made of the two materials are alternately stacked. For another example, the materials of the third antireflection film layers 41 include two or more materials, and the third antireflection film layers 41 of these multiple materials are alternately stacked. In this embodiment, the arrangement manner of the plurality of third antireflection film layers 41 is not limited, and the materials of two adjacent third antireflection film layers 41 are different.

The number and thickness of the third antireflection film layers 41 may be determined through simulation tests, and if the number of the third antireflection film layers 41 is multiple, the specific arrangement manner of the multiple third antireflection film layers 41 may also be determined through simulation tests.

It should be noted that, the shapes of the heating antireflection film 2 and the optical antireflection film 4 are both matched with the shape of the window substrate 1, for example, as shown in fig. 1 to 10, the shape of the window substrate 1 is a plate, the shapes of the heating antireflection film 2 and the optical antireflection film 4 are a plate or a sheet, and as shown in fig. 11, the shape of the window substrate 1 is a hemisphere, and the shapes of the heating antireflection film 2 and the optical antireflection film 4 may be a hemisphere.

Based on the above, the optical window includes a window substrate 1, a heating antireflection film 2 and an optical antireflection film 4, the heating antireflection film 2 is located on an inner surface of the window substrate 1, the optical antireflection film 4 is located on an outer surface of the window substrate 1, the inner surface of the window substrate 1 is a surface facing the lens assembly 201 and is also a surface located inside the optical lens, and the outer surface of the window substrate 1 is a surface facing away from the lens assembly 201 and is also a surface located outside the optical lens.

The heating antireflection film 2 comprises a heating film layer 21, a first antireflection film layer 22 and a second antireflection film layer 23, the heating film layer 21 is used for heating the optical window, and the first antireflection film layer 22 and the second antireflection film layer 23 are used for improving the light transmittance of the optical window. One or more first antireflection film layers 22 and one or more second antireflection film layers 23 may be provided, and the heating film layer 21 may be sandwiched between all of the first antireflection film layers 22 and all of the second antireflection film layers 23 to ensure that the heating film layer 21 is positioned in an inner layer, not an outermost layer, of the heating antireflection film 2.

The optical antireflection film 4 includes one or more third antireflection film layers 41, and the number of the third antireflection film layers 41 is used to increase the light transmittance of the optical window.

In the film layer design stage, the number and arrangement mode of the first antireflection film layers 21 and the number and arrangement mode of the second antireflection film layers 22 in the heating antireflection film 2 can be determined through a reflection spectrum curve of the heating antireflection film 2 in a simulation test and a specific application scene of the optical window. For example, as shown in fig. 12, a spectrum curve of a simulation test of the heating antireflection film 2 shows that the reflectivity of the heating antireflection film 2 is less than 1% in a wavelength range from 420nm to 1000nm, which can meet the application requirements of an image acquisition device (e.g., a monitoring device). After the heating antireflection film 2 is laid on the inner surface of the window substrate 1 of the optical window, if the optical antireflection film 4 is further laid on the outer surface of the window substrate 1, the light transmittance of the optical window can reach more than 96%, while in the existing scheme, the light transmittance of the optical window with the heating film layer laid on the outermost layer is about 80%, and compared with the optical window with the heating film layer laid on the outermost layer, the light transmittance of the optical window in the scheme can be improved by about 16%.

After the film layer design of the optical window is completed, the optical window can be processed according to the designed optical window, and the processing process can be as follows:

the first antireflective film layer 22 may be first deposited on the interior surface of the window substrate 1 by, for example, but not limited to, vacuum evaporation, vacuum ion, vacuum magnetron sputtering, chemical deposition, and liquid material coating. After the deposition of the first antireflection film layer 22 is completed, a heating film layer 21 is deposited on the upper surface of the first antireflection film layer 22 on the outermost layer away from the window substrate 1, which may be any one of the above manners. After the deposition of the heating film layer 21 is completed, since the second anti-reflection film layer 23 has the notch 231 to expose the surface of the heating film layer 21, a tool fixture may be replaced when the second anti-reflection film layer 23 is deposited, the tool fixture is different from the tool fixtures for depositing the first anti-reflection film layer 22 and the heating film layer 21, the tool fixture used for depositing the second anti-reflection film layer 23 can block the electrode mounting area, and the method for depositing the second anti-reflection film layer 23 may be any one of the above methods. After the deposition of the second anti-reflection film layer 23 is completed, the two electrodes 24 are respectively placed in the gaps 231 and fixed on the surface of the heating film layer 21 by means of conductive adhesive.

The outer surface of the window substrate 1 may also be deposited with an optical antireflection film 4 as described above, and the deposition process may be similar to that described above. Wherein, the process of depositing the optical antireflection film 4 on the outer surface of the window substrate 1 and the process of depositing the heating antireflection film 2 on the inner surface of the window substrate 1 are not in sequence. Furthermore, other film layers, such as a water-proof film, may be deposited on the outer surface of the viewing window substrate 1 depending on the particular application of the optical viewing window.

In this embodiment, the optical window includes a heating antireflection film, the heating antireflection film is laid on the inner surface of the window substrate, and the heating antireflection film has a heating function, so that even if the outer surface of the optical window is frozen, frosted or fogged, the temperature of the optical window is high by heating the heating antireflection film, so that the ice, frost or fog on the outer surface can be evaporated, the outer surface of the optical window is kept in a dry state, light in the environment fully enters the optical lens, the shooting quality of the image acquisition device is further improved, and the definition of a shot image is high.

The heating antireflection film comprises a heating film layer, a first antireflection film layer and a second antireflection film layer, and the heating film layer is located between the first antireflection film layer and the second antireflection film layer. With the heating antireflection film with the structure, the number and the arrangement mode of the first antireflection film layers and the number, the thickness and the arrangement mode of the second antireflection film layers are determined through simulation tests, so that the heating antireflection film has high light transmittance. Therefore, the optical window with the heating antireflection film can realize a heating function and ensure higher light transmittance.

The present application further provides an optical lens, referring to fig. 1, the optical lens 200 includes a lens assembly 201 and the above-mentioned optical window 202, as shown in fig. 1, the lens assembly 201 and the optical window 202 are coaxially arranged with the light sensing device 100, the optical window 202 is located at the outermost layer of the optical lens, and the heating antireflection film 2 is close to the lens assembly 201 relative to the window substrate. For the description of the optical lens, reference may be made to the above description, and details are not repeated here.

The present application further provides an image capturing apparatus, which may be a monitoring apparatus, or a video camera, a video recorder, and the like, and includes a light sensing device 100, an ISP, and the optical lens 200, where the light sensing device 100 is configured to perform photoelectric conversion on an optical signal passing through the optical lens 200 to generate an original image, and the ISP is configured to perform image processing on the original image. For the descriptions of the photosensitive device 100 and the ISP, reference may be made to the above description, and details are not repeated here.

The optical lens of the image acquisition equipment comprises the optical window, and the optical window comprises the heating antireflection film which is laid on the inner surface of the window substrate and has a heating function, so that even if the outer surface of the optical window is frozen, frosted or fogged, the temperature of the optical window is higher by heating the heating antireflection film, the ice, frost or fog on the outer surface can be evaporated, the outer surface of the optical window is kept in a dry state, light in the environment fully enters the optical lens, the shooting quality of the image acquisition equipment is improved, and the definition of a shot image is higher.

The above description is only one embodiment of the present application and should not be taken as limiting the present application, and any modifications, equivalents, improvements, etc. made within the principle of the present application should be included in the protection scope of the present application.

Claims

1. An optical window, characterized in that it comprises a window substrate (1) and a heating antireflection film (2);

the heating antireflection film (2) is positioned on the surface, perpendicular to the light entering direction, of the window substrate (1);

the heating antireflection film (2) comprises a heating film layer (21), m first antireflection film layers (22) and n second antireflection film layers (23), wherein m and n are positive integers;

the m first antireflection film layers (22), the heating film layer (21) and the n second antireflection film layers (23) are sequentially stacked and arranged.

2. The optical window of claim 1, wherein m is greater than or equal to 2, and the materials of two adjacent first antireflection film layers (22) are different.

3. The optical window of claim 1 or 2, wherein n is greater than or equal to 2, and the adjacent two second antireflection film layers (23) are made of different materials.

4. The optical window of any one of claims 1 to 3, wherein the material of each first antireflection film layer (22) and the material of each second antireflection film layer (23) are any one of silicon dioxide, titanium dioxide, magnesium fluoride, tantalum pentoxide, niobium pentoxide, and aluminum oxide.

5. The optical window according to any one of claims 1 to 4, wherein the heating film (21) is made of ITO.

6. Optical window according to one of claims 1 to 5, wherein the thickness of the heating film layer (21), of each first antireflection film layer (22) and of each second antireflection film layer (23) is between 5nm and 250 nm.

7. Optical window according to one of claims 1 to 6, in which the heating antireflection film (2) further comprises two electrodes (24);

each electrode (24) is located heating film layer (21) back to the surface of window substrate (1) and at the lateral part of the optical view field region (3) of optical window, optical view field region (3) are the region of optical window that supplies light to pass through.

8. Optical window according to claim 7, characterized in that one of the two electrodes (24) is located on a first side of the optical field region (3) and the other is located on a second side of the optical field region (3), the first and second sides of the optical field region (3) being located opposite to each other.

9. Optical window according to claim 7, characterized in that the surface of the heating film layer (21) facing away from the window substrate (1) has an exposed area (211) on the side of the optical field region (3), the electrodes (24) being electrically connected to the heating film layer (21) via the exposed area (211).

10. Optical window according to claim 9, characterized in that the n second antireflection film layers (23) are remote from the window substrate (1) with respect to the m first antireflection film layers (22);

the second antireflection film layer (23) has a notch (231) at a side of the optical view field region (3) to form the exposed region (211).

11. Optical window according to claim 9, characterized in that the n second antireflection film layers (23) are remote from the window substrate (1) with respect to the m first antireflection film layers (22);

the area of the second antireflection film layer (23) is smaller than that of the heating film layer (21) to form the exposed region (211).

12. Optical window according to one of claims 1 to 11, further comprising an optical antireflection film (4);

the optical antireflection film (4) is positioned on the surface of the window substrate (1) back to the heating antireflection film (2);

the optical antireflection film (4) comprises at least one third antireflection film layer (41), and the at least one third antireflection film layer (41) is arranged in a stacked manner.

13. The optical window of claim 12, wherein each third antireflection film layer (41) is made of any one of silicon dioxide, titanium dioxide, magnesium fluoride, tantalum pentoxide, niobium pentoxide, and aluminum oxide.

14. Optical window according to one of claims 1 to 13, characterized in that the window substrate (1) is made of any of glass, optical resin and polycarbonate.

15. An optical lens, characterized in that it comprises a lens assembly (201) and an optical window (202) according to any one of claims 1 to 14, and in that the optical window (202) is located at the outermost layer of the optical lens, and in that the heating antireflection film (2) is located close to the lens assembly (201) with respect to the window substrate (1).

16. An image pickup apparatus characterized by comprising a light sensing device (100), an image signal processor ISP, and an optical lens (200) according to claim 15;

the photosensitive device (100) is used for performing photoelectric conversion on an optical signal passing through the optical lens (200) to generate an original image;

and the ISP is used for carrying out image processing on the original image.