Anti-reflection film and optical lens

Abstract

The utility model relates to an anti-reflection film and an optical lens, the anti-reflection film comprises n metal oxide film layers and n'ceramic film layers which are staggered and laminated along the thickness direction, and n and n 'are respectively integers; wherein the metal oxides of the n metal oxide film layers are respectively and independently titanium dioxide or tantalum pentoxide, and the ceramic materials of the n'ceramic film layers are respectively and independently silicon dioxide, silicon nitride, silicon carbide or magnesium fluoride; the optical lens comprises an optical substrate and the antireflection film arranged on the optical substrate. The antireflection film provided by the utility model has the advantage of increasing the light transmittance, and can be matched with the transmittance of a grating structure through stacking at least two types of materials with refractive index differences, thereby achieving the effect that the coupling-in region, the transition region and / or the coupling-out region of the optical lens are approximately transparent.

Description

Technical Field

[0001] The utility model relates to the technical field of optical thin films, in particular to an antireflection film and an optical lens. Background Technique

[0002] When AR glasses adopting diffractive optical waveguide technology enter the consumer market, they face a prominent problem, that is, obvious grating regions can be observed. This phenomenon makes it difficult to coordinate the appearance of AR glasses with that of traditional myopia or hyperopia glasses, damaging the product's appearance design. For users, the existence of the grating effect also interferes with the clear observation of the real environment. The root cause of this problem is that the grating region reduces the light transmittance of the substrate material, and the difference in light transmittance between the grating structure region and the non-structure region further highlights the grating effect.

[0003] Chinese Patent No. CN117055159A discloses a diffractive optical waveguide and a near-eye display device. The diffractive optical waveguide includes a waveguide substrate and an input grating region and an output grating region arranged on the waveguide substrate. The input grating region includes an input grating, and the output grating region includes output gratings periodically arranged in at least two directions; the grating period and grating vector of the output grating satisfy:

[0004] ;

[0005] wherein, D2 is the grating period in one direction of the output grating, D1 is the grating period in the other direction of the output grating, n a is the refractive index of air, n b is the refractive index of the waveguide substrate, λ is the wavelength, α is half of the field of view angle, and β is the included angle between the grating vectors in one direction and the other direction of the output grating, so as to improve the light transmittance of the diffractive optical waveguide.

[0006] The existing technical solutions have several defects: in order to solve the visibility problem of the grating region and affect the wearing experience of users, the above device attempts to improve the light transmittance of the grating region by two-dimensional modulation of the grating period, in order to reduce the difference in light transmittance between the structure region and the non-structure region. However, in the actual processing process, this method exposes significant problems. For example, two-dimensional periodic modulation of the grating will increase the processing difficulty, and will change the light transmission characteristics of the original grating, and the improvement effect of this method on the light transmittance difference is quite limited.

[0007] In view of this, the present utility model proposes a new solution. By designing the unstructured area of the waveguide substrate, the transmittance of the structured area within the entire visible light spectrum is matched. This design does not introduce additional complex process flows and does not impose any additional restrictions on the design of the optical waveguide optical lens. At the same time, it can achieve the transmittance matching between the grating area and the non-grating area within the entire visible light range. In this way, we can truly achieve the effect that the grating area is approximately transparent. Summary of the Utility Model

[0008] Aiming at the deficiencies existing in the prior art, the first object of the present utility model is to provide an anti-reflection film, which has the advantage of increasing the light transmittance.

[0009] The second object of the present utility model is to provide an optical lens. By performing a film system treatment on the unstructured area of the waveguide substrate, the refractive index difference between the grating structure and other structures at each visible light wavelength approaches 0, so that users are not easily able to observe the existence of the grating structure.

[0010] To achieve the above first object, the present invention provides the following technical solution:

[0011] An anti-reflection film includes n metal oxide film layers and n' ceramic film layers that are alternately arranged and stacked along the thickness direction, where n and n' are integers respectively; among them, the metal oxides of the n metal oxide film layers are independently titanium dioxide or tantalum pentoxide, and the ceramic materials of the n' ceramic film layers are independently silicon dioxide, silicon nitride, silicon carbide or magnesium fluoride.

[0012] By adopting the above technical solution, the anti-reflection film has a high transmittance (>85%) within the visible light range. Its metal oxide film layer and ceramic film layer are respectively formed by coating means, and the coating means include but are not limited to thermal evaporation, electron beam evaporation, magnetron sputtering, PECVD, ALD, MOCVD, etc. Each layer of the metal oxide film layer and ceramic film layer can optionally choose a metal oxide and a ceramic material respectively, as long as the refractive indices of adjacent two layers of materials are different. By stacking at least two types of materials with refractive index differences, it can match the transmittance of the grating structure, thereby achieving the effect that the coupling area, turning area and / or coupling-out area of the optical lens are approximately transparent.

[0013] The present utility model is further set as: n and n' are respectively 2 to 4.

[0014] By adopting the above technical solution,

[0015] The present utility model is further set as: the total thickness of the anti-reflection film is 0.25 to 2.50 μm.

[0016] By adopting the above technical solution, it has a good high transmittance within the visible light range.

[0017] The present utility model is further configured such that the single-layer thickness of the n metal oxide films is 5.00 - 160.00 nm, and the laminated thickness is 100.00 - 165.00 nm.

[0018] By adopting the above technical solution, it has good high transmittance in the visible light range.

[0019] The present utility model is further configured such that the single-layer thickness of the n' ceramic films is 5.00 - 2210.00 nm, and the laminated thickness is 100.00 - 2325.00 nm.

[0020] By adopting the above technical solution, it has good high transmittance in the visible light range.

[0021] The present utility model is further configured to include n metal oxide films and n' ceramic films that are alternately arranged and laminated along the thickness direction. The n metal oxide films are successively titanium dioxide films with single-layer thicknesses of 76.86 nm, 20.12 nm, and 5.04 nm, and the n' ceramic films are successively silicon dioxide films with single-layer thicknesses of 2210.00, 105.88 nm, and 5.69 nm.

[0022] By adopting the above technical solution, the antireflection film has a high transmittance of >85% in the visible light range.

[0023] The present utility model is further configured to include n metal oxide films and n' ceramic films that are alternately arranged and laminated along the thickness direction. The n metal oxide films are successively tantalum pentoxide films with single-layer thicknesses of 87.69 nm and 45.27 nm, and the n' ceramic films are successively silicon dioxide films with single-layer thicknesses of 11.43 nm and 124.47 nm.

[0024] By adopting the above technical solution, the antireflection film has a high transmittance of >85% in the visible light range.

[0025] The present utility model is further configured to include n metal oxide films and n' ceramic films that are alternately arranged and laminated along the thickness direction. The n metal oxide films are successively tantalum pentoxide films with single-layer thicknesses of 156.72 nm and 7.38 nm, and the n' ceramic films are successively magnesium fluoride films with single-layer thicknesses of 60.42 nm and 42.74 nm.

[0026] By adopting the above technical solution, the antireflection film has a high transmittance of >85% in the visible light range.

[0027] To achieve the above second object, the present invention provides the following technical solution:

[0028] An optical lens includes an optical substrate and the above-mentioned antireflection film disposed on the optical substrate.

[0029] By adopting the above technical solution, the optical lens has a high transmittance of > 85% in the visible light range.

[0030] The present utility model is further configured such that: the optical substrate is a waveguide substrate with a grating structure, the grating structure is disposed in the structural region of the waveguide substrate, and the antireflection film is disposed in the non-structural region of the waveguide substrate.

[0031] By adopting the above technical solution, the refractive index of the waveguide substrate can be above 2.0. By performing a film system treatment on the non-structural region of the waveguide substrate, the refractive index difference between the grating structure and other structures at each visible light wavelength approaches 0, so that it is difficult for users to observe the existence of the grating structure.

[0032] In summary, the beneficial technical effects of the present utility model are as follows:

[0033] 1. The antireflection film of the present utility model has the advantage of increasing the light transmittance. By stacking at least two types of materials with refractive index differences, it can match the transmittance of the grating structure, thereby achieving an approximately transparent effect in the coupling region, turning region, and / or coupling-out region of the optical lens;

[0034] 2. The optical lens of the present utility model performs a film system treatment on the non-structural region of the waveguide substrate, so that the refractive index difference between the grating structure and other structures at each visible light wavelength approaches 0, making it difficult for users to observe the existence of the grating structure. Description of the Drawings

[0035] Figure 1 It is a schematic structural diagram of the optical lens of Embodiment 1 of the present utility model.

[0036] Figure 2 It is a schematic structural diagram of the antireflection film of Embodiment 1 of the present utility model.

[0037] Figure 3 It is a transmittance test chart of the optical substrate of Embodiment 1 of the present utility model.

[0038] Figure 4 It is a transmittance test chart of the optical lens of Embodiment 1 of the present utility model.

[0039] Figure 5 It is a transmittance test chart of the optical lens of Embodiment 2 of the present utility model.

[0040] Figure 6 It is a transmittance test chart of the optical lens of Embodiment 3 of the present utility model.

[0041] In the figure, 1 is an optical substrate; 11 is a waveguide substrate; 12 is a grating structure; 2 is an antireflection film; 21 is a metal oxide film layer; 22 is a ceramic film layer. Specific Embodiment

[0042] In order to make the technical means, creative features, achieved purposes and functions realized by the present utility model clearer and easier to understand, the present utility model will be further described below with reference to the accompanying drawings and specific embodiments.

[0043] Example 1: Refer to Figure 1 , an optical lens disclosed by the present utility model, comprising an optical substrate 1 and an antireflection film 2. Among them, the optical substrate 1 is set as a waveguide substrate 11 (n = 2.0, optical glass) with a grating structure 12, the grating structure 12 is arranged in the structure area of the waveguide substrate 11, and the antireflection film 2 is arranged in the non-structure area of the waveguide substrate 11. The setting of the antireflection film 2 makes the refractive index difference between the grating structure 12 and other structures approach 0 at each visible light wavelength, so that users are not likely to observe the existence of the grating structure 12.

[0044] Refer to Figure 2 , specifically, the antireflection film 2 includes 3 metal oxide film layers 21 and 3 ceramic film layers 22 arranged and laminated alternately along the thickness direction. The total thickness of the antireflection film 2 is 2423.59 nm. The single-layer thickness of these metal oxide film layers 21 is 5.01 - 76.86 nm, and the laminated thickness is 102.02 nm. The single-layer thickness of these ceramic film layers 22 is 5.69 - 2210 nm, and the laminated thickness is 2321.57 nm.

[0045] In addition, the materials and thicknesses of each layer of the optical lens are shown in Table 1.

[0046] Table 1

[0047] Number of layers Film layer material Physical thickness / nm 0 Optical substrate / 1 <![CDATA[TiO2]]> 76.86 2 <![CDATA[SiO2]]> 2210 3 <![CDATA[TiO2]]> 20.12 4 <![CDATA[SiO2]]> 105.88 5 <![CDATA[TiO2]]> 5.04 6 <![CDATA[SiO2]]> 5.69

[0048] The specific implementation principle of this embodiment is that by performing film system matching of the antireflection film 2 on the non-structure area of the diffractive optical waveguide, the transmittance of the grating structure 12 area and the non-structure area remains the same within the visible light range, so as to achieve the effect that the structure area is not easily noticed by users. For example, a common optical waveguide structure includes at least 1 coupling-in area, 0 - 2 turning areas, at least 1 coupling-out area and other structure areas. Since the coupling-out area is directly in front of the human eye, the visual effect of this area is more sensitive to the user's perception. Therefore, first take the transmittance of the coupling-out area as an example to consider the film system matching problem. Correspondingly, the turning area also exists on the surface of the optical substrate 1. By the same means, film system matching of the antireflection film 2 is performed on the non-structure area near the turning area, and the turning area can also be made not easily noticed by users.

[0049] For the grating structure 12 in the coupling-out region for determining the structural parameters, the transmittance curve of this region in the visible light range can be obtained through a spectrometer, as Figure 3 shown. The specific values of this transmittance curve are affected by structural parameters such as the refractive index of the grating and the grating period. Generally speaking, due to the low diffraction efficiency in the coupling-out region, its light transmittance performance is relatively good (>85%). According to this transmittance curve, a film system design is carried out on the non-structural region outside the coupling-out region using simulation software, so that the optical transmittance of the non-structural region is as consistent as possible with that of the coupling-out region, and the transmittance error <3%.

[0050] The film system can select the stacking of SiO2 and TiO2. Of course, it can also be other materials with refractive index differences, such as SiN, TiO2, etc. The material selection matches the performance, and the types of materials can be the stacking of two materials, or the stacking of three or more materials according to certain rules. As shown in Table 1 above, the antireflection film 2 design is carried out on the waveguide substrate 11 made of optical glass with n = 2.0, and its transmittance curve in the visible light range is calculated, as Figure 4 shown. From Figure 4 it can be seen that the transmittance matches very well with that of the grating structure 12 in the coupling-out region of the waveguide, thus achieving an approximately transparent visual effect in the coupling-out region.

[0051] Example 2: An optical lens disclosed by the present utility model, and the materials and thicknesses of each layer in the optical lens are shown in Table 2.

[0052] Table 2

[0053] Number of layers Film layer material Physical thickness / nm 0 Optical substrate / 1 <![CDATA[Ta2O5]]> 87.69 2 <![CDATA[SiO2]]> 11.43 3 <![CDATA[Ta2O5]]> 45.27 4 <![CDATA[SiO2]]> 124.47

[0054] As shown in Table 2 above, the antireflection film 2 design is carried out on the waveguide substrate 11 made of optical glass with n = 2.0, and its transmittance curve in the visible light range is calculated, as Figure 5 shown. From Figure 5 it can be seen that the transmittance matches very well with that of the grating structure 12 in the coupling-out region of the waveguide, thus achieving an approximately transparent visual effect in the coupling-out region.

[0055] Example 3: An optical lens disclosed by the present utility model, and the materials and thicknesses of each layer in the optical lens are shown in Table 2.

[0056] Table 3

[0057] Number of layers Film layer material Physical thickness / nm 0 Optical substrate / 1 <![CDATA[Ta2O5]]> 156.72 2 <![CDATA[MgF2]]> 60.42 3 <![CDATA[Ta2O5]]> 7.38 4 <![CDATA[MgF2]]> 42.74

[0058] As shown in Table 3 above, the antireflection film 2 design is carried out on the waveguide substrate 11 made of optical glass with n = 2.0, and its transmittance curve in the visible light range is calculated, as Figure 6 shown. FromFigure 6 It can be seen that the transmittance matches very well with the transmittance of the grating structure 12 in the coupling-out region of the waveguide, thereby achieving an approximately transparent visual effect in the coupling-out region.

[0059] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention rather than to limit them. Although the present invention has been described in detail with reference to the preferred embodiments, those of ordinary skill in the art should understand that the technical solutions of the present invention can be modified or equivalently replaced without departing from the spirit and scope of the technical solutions of the present invention, and they should all be covered within the scope of the claims of the present invention.

Claims

1. An antireflection film, characterized in that: It comprises n metal oxide film layers (21) and n' ceramic film layers (22) which are arranged alternately and stacked along the thickness direction, wherein n and n' are integers respectively; wherein the metal oxides of the n metal oxide film layers (21) are each independently titanium dioxide or tantalum pentoxide, and the ceramic materials of the n' ceramic film layers (22) are each independently silicon dioxide, silicon nitride, silicon carbide or magnesium fluoride.

2. An antireflection film (2) according to claim 1, characterized in that: The n and n' are 2 to 4 respectively.

3. An antireflection film (2) according to claim 2, characterized in that: The total thickness of the antireflection film (2) is 0.25-2.50 μm.

4. An antireflection film (2) according to claim 3, characterized in that: The single layer thickness of the n metal oxide film layers (21) is 5.00-160.00 nm, and the stacked thickness is 100.00-165.00 nm.

5. The antireflection film (2) according to claim 3, characterized in that: The single layer thickness of the n' ceramic film layers (22) is 5.00-2210.00 nm, and the stacked thickness is 100.00-2325.00 nm.

6. An antireflection film (2) according to claim 1, characterized in that: The invention comprises n metal oxide film layers (21) and n' ceramic film layers (22) which are arranged alternately and stacked along the thickness direction, wherein the n metal oxide film layers (21) are sequentially arranged as titanium dioxide film layers with single layer thicknesses of 76.86 nm, 20.12 nm and 5.04 nm, and the n' ceramic film layers (22) are sequentially arranged as silicon dioxide film layers with single layer thicknesses of 2210.00 nm, 105.88 nm and 5.69 nm.

7. An antireflection film (2) according to claim 1, characterized in that: The invention comprises n metal oxide film layers (21) and n' ceramic film layers (22) which are arranged alternately and stacked along the thickness direction, wherein the n metal oxide film layers (21) are sequentially arranged as tantalum pentoxide film layers with single layer thicknesses of 87.69 nm and 45.27 nm, and the n' ceramic film layers (22) are sequentially arranged as silicon dioxide film layers with single layer thicknesses of 11.43 nm and 124.47 nm.

8. An antireflection film (2) according to claim 1, characterized in that: The invention comprises n metal oxide film layers (21) and n' ceramic film layers (22) which are arranged alternately and stacked along the thickness direction, wherein the n metal oxide film layers (21) are sequentially arranged as tantalum pentoxide film layers with single layer thicknesses of 156.72nm and 7.38nm, and the n' ceramic film layers (22) are sequentially arranged as magnesium fluoride film layers with single layer thicknesses of 60.42nm and 42.74nm.

9. An optical lens, characterized in that: It comprises an optical substrate (1), and an anti-reflection film (2) according to any one of claims 1 to 8, which is arranged on the optical substrate (1).

10. An optical lens according to claim 9, characterized in that: The optical substrate (1) is configured as a waveguide substrate (11) with a grating structure (12), the grating structure (12) is arranged in a structured area of ​​the waveguide substrate (11), and the anti-reflection film (2) is arranged in a non-structured area of ​​the waveguide substrate (11).

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