Coating method of light guide device, light guide device and head-mounted display device

Abstract

Embodiments of the present application provide a coating method of a light guide device, the light guide device and a head-mounted display device. The coating method of the light guide device comprises: providing a substrate, and forming a coupling-in region and a coupling-out region on the substrate; forming a metal layer on the coupling-in region while shielding the coupling-out region, and controlling the thickness of the metal layer to be greater than 15 nm; and forming a non-metal material layer on the substrate without shielding the coupling-in region, and the non-metal material layer covering at least the coupling-out region.

Description

Technical Field

[0001] This application relates to the field of optical imaging technology, and more specifically, to a coating method for a light guide device, a light guide device, and a head-mounted display device. Background Technology

[0002] Augmented Reality (AR) is a technology that combines virtual information with the real world. Diffractive waveguides are considered the best optical display solution currently available for AR. Diffractive waveguides often require separate coating areas; for example, the materials and thicknesses of the coatings deposited in the coupling-in and coupling-out regions may differ. Therefore, the process requires first masking one region to deposit the coating, and then masking the other region to deposit the coating. Summary of the Invention

[0003] The purpose of this application is to provide a coating method for a light guide device, a light guide device, and a new technical solution for a head-mounted display device.

[0004] In a first aspect, this application provides a coating method for a light guide device. The coating method for the light guide device includes:

[0005] A substrate is provided, and a coupling-in region and a coupling-out region are formed on the substrate;

[0006] While shielding the coupling-out region, a metal layer is formed on the coupling-in region, and the thickness of the metal layer is controlled to be greater than 15 nm; and

[0007] Without obscuring the coupling region, a non-metallic material layer is formed on the substrate, and the non-metallic material layer at least covers the coupling region.

[0008] Optionally, the coupling region includes a coupling grating, and the structure of the metal layer corresponds to the structure of the coupling grating.

[0009] Optionally, the thickness of the metal layer is H, and 16nm≤H≤100nm.

[0010] Optionally, the metal layer may be made of aluminum, gold, copper, or silver.

[0011] Optionally, the metal layer is further covered with the non-metallic material layer;

[0012] The coupling region includes a coupling grating and a non-metallic material layer covering the coupling grating, and the coupling grating and the coupling grating form a closed grating vector polygon.

[0013] Optionally, the metal layer is formed in the coupling region by deposition, including atomic layer deposition (ALD), physical vapor deposition (PVD), high-temperature chemical vapor deposition (CVD), or plasma-enhanced chemical vapor deposition (PECVD).

[0014] Optionally, the material of the non-metallic material layer includes silicon dioxide, titanium dioxide, aluminum oxide, or embossing adhesive.

[0015] Secondly, embodiments of this application provide a light guide device, which is manufactured using the coating method for light guide devices as described in the first aspect.

[0016] Thirdly, embodiments of this application provide a light guide device, the light guide device including a substrate, and a coupling-in region and a coupling-out region disposed on the substrate;

[0017] The coupling region is at least covered with a metal layer;

[0018] The coupling region is covered with a non-metallic material layer.

[0019] Fourthly, embodiments of this application provide a head-mounted display device, the head-mounted display device comprising:

[0020] The shell; and,

[0021] The light guide device as described in the second or third aspect.

[0022] The beneficial effects of this application are as follows:

[0023] According to the coating method of the light guide device provided in the embodiments of this application, by first forming a metal layer of a certain thickness in the coupling region and then forming a non-metallic material layer in the coupling region, the coupling region does not need to be blocked. This is because the metal material has a skin effect. After exceeding its skin depth, the excess thickness of the metal layer will no longer affect the diffraction behavior of the coupling region. The design of this metal layer makes it unnecessary to block the coupling region when fabricating the non-metallic material layer on the coupling region, which effectively reduces the number of processes and lowers the production cost.

[0024] Other features and advantages of this specification will become clear from the following detailed description of exemplary embodiments with reference to the accompanying drawings. Attached Figure Description

[0025] The accompanying drawings, which are incorporated in and form part of this specification, illustrate embodiments of this specification and, together with their description, serve to explain the principles of this specification.

[0026] Figure 1 This is a schematic diagram of the structure of the light guide device provided in the embodiments of this application;

[0027] Figure 2 This is a schematic diagram of a metal layer formed on the coupling region provided in an embodiment of this application;

[0028] Figure 3 for Figure 2 The diffraction efficiency curve of the metal layer is shown in the figure;

[0029] Figure 4 In order to be in Figure 2 A schematic diagram of a non-metallic material layer formed on a metallic layer;

[0030] Figure 5 for Figure 4 The diffraction efficiency curves of the non-metallic material layer covering the metal layer are shown in the figure.

[0031] Figure 6 This is a schematic diagram showing a silicon oxide layer covering the coupling region of a light guide device.

[0032] Figure 7 for Figure 6 The diffraction efficiency curve of the coupling region is shown in the figure;

[0033] Figure 8 A schematic diagram showing the stacking of a titanium oxide layer and a silicon oxide layer in the coupling region of a light guide device;

[0034] Figure 9 for Figure 8 The diffraction efficiency curve of the coupling region is shown in the figure.

[0035] Explanation of reference numerals in the attached figures:

[0036] 100, Substrate; 101, Coupling region; 102, Coupling out region; 200, Metal layer; 300, Non-metallic material layer; 400, Titanium oxide layer; 500, Silicon oxide layer. Detailed Implementation

[0037] Various exemplary embodiments of the present application will now be described in detail with reference to the accompanying drawings. It should be noted that, unless otherwise specifically stated, the relative arrangement, numerical expressions, and values ​​of the components and steps set forth in these embodiments do not limit the scope of the present application.

[0038] The following description of at least one exemplary embodiment is merely illustrative and is in no way intended to limit the scope of this application and its application or use.

[0039] Technologies and equipment known to those skilled in the art may not be discussed in detail, but where appropriate, such technologies and equipment should be considered part of the specification.

[0040] In all the examples shown and discussed herein, any specific values ​​should be interpreted as merely exemplary and not as limitations. Therefore, other examples of exemplary embodiments may have different values.

[0041] It should be noted that similar labels and letters in the following figures indicate similar items; therefore, once an item is defined in one figure, it does not need to be discussed further in subsequent figures.

[0042] The coating method for the light guide device, the light guide device, and the head-mounted display device provided in the embodiments of this application will be described in detail below with reference to the accompanying drawings.

[0043] According to one aspect of the embodiments of this application, a coating method for a light guide device is provided. The final manufactured light guide device is, for example, a diffractive waveguide element, which can be applied to AR optical solutions. Both the coupling-in region and the coupling-out region of the light guide device are formed with a predetermined film layer.

[0044] It should be noted that the traditional coating method for diffractive waveguide elements involves fabricating the coupling-in and coupling-out regions of the waveguide element, then shielding the coupling-out region, forming a metal oxide layer on the coupling-in region, and then shielding the coupling-in region again to form a non-metal oxide layer on the coupling-out region. This process involves two shielding steps. The reason for this design is that the coupling-in and coupling-out regions have different requirements for light diffraction behavior, resulting in different coatings.

[0045] The method for manufacturing a light guide device provided in this application includes the following steps:

[0046] Step S1: Provide a substrate 100, and form a coupling-in region 101 and a coupling-out region 102 on the substrate 100, see [link to previous step]. Figure 1 ;

[0047] Step S2: With the coupling-out region 102 shielded, a metal layer 200 is formed on the coupling-in region 101, and the thickness of the metal layer 200 is controlled to be greater than 15 nm. See [link to relevant documentation]. Figure 2 ;as well as

[0048] Step S3: Without obscuring the coupling region 101, a non-metallic material layer 300 is formed on the substrate 100, and the non-metallic material layer 300 at least covers the coupling region 102.

[0049] According to the coating method of the light guide device provided in the above embodiments of this application, by first forming a metal layer 200 of a certain thickness at the location of the coupling region 101, the coupling region 101 can be unobstructed when the non-metallic material layer 300 is formed at the location of the coupling region 102. This is because metallic materials have a skin effect; beyond their skin depth, the excess thickness of the metal layer 200 will no longer affect the diffraction behavior (diffraction efficiency) of the coupling region 101. The design of the metal layer 200 allows the coupling region 101 to be unobstructed when the non-metallic material layer 300 is fabricated on the coupling region 102, effectively reducing the number of steps and lowering production costs.

[0050] In other words, compared with traditional diffractive waveguide coating schemes, the fabrication scheme provided in this application does not require coating operations in separate regions.

[0051] The solution provided in this application embodiment can eliminate the need for a masking step. A metal layer 200 is formed in the coupling region 101. Based on the skin effect of the metal material, even if a non-metallic material layer 300 is formed on the metal layer 200, it will not affect the diffraction efficiency. That is, the diffraction efficiency requirement for the coupling region 101 can be guaranteed, thereby ensuring the optical performance of the light guide device and improving the image quality.

[0052] In step S1, the coupling-in region 101 and the coupling-out region 102 can be arranged in any combination on the same surface of the substrate 100. Of course, the coupling-in region 101 and the coupling-out region 102 can also be located on different surfaces of the substrate 100.

[0053] The coupling region 101 includes a coupling grating.

[0054] The coupling grating can be any type of one-dimensional grating or any type of two-dimensional grating. For example, the coupling grating in the coupling region 101 is a blazed grating.

[0055] The coupling region 102 includes a coupling grating.

[0056] The coupled grating can be any type of one-dimensional grating or any type of two-dimensional grating.

[0057] In step S2, the thickness of the metal layer 200 is designed to be greater than the skin depth of visible light in the metal layer 200. In this way, after exceeding its skin depth, the excess thickness of the metal layer 200 will no longer affect the diffraction behavior of the coupling grating in the coupling region 101 for visible light.

[0058] Specifically, see Figure 2As shown, a metal layer 200 with a thickness greater than 15 nm is first formed on the coupling region 101. At this point, based on the skin effect of the material, the diffraction efficiency curve of the coupling region 101 can be seen in [reference needed]. Figure 3 .

[0059] In step S3, since a metal layer 200 with a thickness greater than 15 nm has already been formed in the coupling region 101 in step S2, a non-metallic material layer 300 covering the coupling region 102 can be directly formed on the substrate 100 without shielding the coupling region 101. In other words, when fabricating the non-metallic material layer on the coupling region 102, the process of shielding the coupling region 101 can be omitted; that is, there is no need to avoid the coupling region 101, and the non-metallic material layer 300 can be directly formed on the substrate 100, which simplifies the process.

[0060] In step S3, since the coupling-in region 101 is not shielded, and the non-metallic material layer 300 is directly formed on the substrate 100, the non-metallic material layer 300 covers not only the designated coupling-out region 102 but also the unshielded coupling-in region 101. (See [link to previous section]). Figure 4 At this time, the non-metallic material layer 300 formed on the coupling region 101 is stacked on the metallic layer 200 of a certain thickness. Based on the skin effect of the metallic material, when the incident light undergoes diffraction in the coupling region 101, the efficiency curve of the coupling region 101 is as follows: Figure 5 As shown, it is similar to Figure 3 A comparison of the diffraction efficiency curves shows that the results remain unchanged. This indicates that the introduction of the metal layer 200, even with the non-metallic material layer 300 superimposed on it, does not affect the diffraction performance of the coupling region 101.

[0061] See Figure 6 , Figure 6 The paper illustrates a conventional light guide device coating scheme. An insertion region 101 is formed on a substrate 100, and a metal oxide layer, such as a titanium oxide layer 400, is formed on this insertion region 101. The trend of the diffraction efficiency curve corresponding to the insertion region 101 can be seen in [reference needed]. Figure 7 Based on this, if the coupling-in region 101 is not shielded, and a non-metallic material layer 300 is formed directly on the coupling-out region 102, for example, the non-metallic material layer 300 is a silicon oxide layer 500, see [link to relevant documentation]. Figure 8 At this time, the diffraction efficiency curve corresponding to the coupling region 101 (and) Figure 7 Compared to the diffraction efficiency curve shown, the overall efficiency was significantly affected, resulting in a decrease in efficiency. (See [reference]). Figure 9 .

[0062] It should be noted that, in the embodiments of this application, the non-metallic material layer 300 can be formed on the substrate 100 by means of film deposition, and the non-metallic material layer 300 can cover the coupling region 102.

[0063] See some examples in this application. Figure 2 The coupling region 101 includes a coupling grating, and the structure of the metal layer 200 corresponds to the structure of the coupling grating.

[0064] For example, the coupling grating used in the coupling region 101 is a blazed grating, see [link to relevant documentation]. Figure 2 The shape of the metal layer 200 needs to correspond to the structural shape of the blazed grating.

[0065] In order for the metal layer 200 to be better integrated with the coupling grating, the structural shape of the metal layer 200 should be adapted to the structural shape of the coupling grating.

[0066] It should be noted that, Figure 2 The coupling grating is not shown; the structure of the metal layer 200 is illustrated using only the structure of a blazed grating as an example. That is, a blazed grating is used as the coupling region, and the metal layer 200 is deposited on its surface.

[0067] In some examples of this application, the thickness of the metal layer 200 is H, and 16nm≤H≤100nm.

[0068] The coating scheme provided in this application mainly involves first forming a metal layer 200 of a certain thickness at the location of the coupling region 101 to avoid the subsequent formation of a non-metallic oxide coating affecting the diffraction efficiency of the coupling region 101. This utilizes the skin effect of metallic materials, which requires a certain thickness of the metal layer. Only after exceeding the skin depth will the excess thickness of the metal layer no longer affect the diffraction behavior of the coupling region.

[0069] For the metal layer 200 in the coupling region 101, a thickness of 16nm to 100nm is commonly used. The thickness of this metal layer is easy to control, relatively easy to process, and will not result in an excessively thick light guide device.

[0070] For example, the thickness of the metal layer 200 can be designed to be 16nm, 25nm, 40nm, 60nm, 95nm, etc. The thickness of the metal layer 200 can be flexibly controlled as needed, and this application does not impose any restrictions on it.

[0071] In some examples of this application, the metal layer 200 is made of aluminum, gold, copper or silver.

[0072] The material of the metal layer 200 provided in the above example is preferably aluminum.

[0073] All of the aforementioned metallic materials exhibit the skin effect, and can be selected based on needs and cost in practical applications. This application does not impose any restrictions on this selection.

[0074] In some examples of this application, the metal layer 200 is further covered by the non-metallic material layer 300, see [link to relevant documentation]. Figure 3 The coupling region 102 includes a coupling grating and a non-metallic material layer 300 covering the coupling grating, and the coupling grating and the coupling grating form a closed grating vector polygon.

[0075] Based on the example above, see Figure 3 The coupling-in region 101 includes a metal layer 200 and a non-metallic material layer 300 stacked on the coupling-in grating. The coupling-out region 102 includes a non-metallic material layer 300 stacked on the coupling-out grating. The non-metallic material layers 300 on the coupling-in region 101 and the coupling-out region 102 can be formed by coating on the substrate 100.

[0076] See Figure 1 The light guide device provided in this application embodiment has a coupling region 101 and a coupling region 102 on the substrate 100. The coupling region 101 is used to couple external light into the substrate 100. The coupling region 102 can have the function of both pupil expansion and coupling, and can extend the coupled light from the coupling region 101 in both the horizontal and vertical dimensions and couple the light out.

[0077] The coupling grating of the coupling region 101 and the coupling grating of the coupling region 102 need to form a closed grating vector polygon.

[0078] Optionally, the coupling region 101 may be composed of a single one-dimensional or two-dimensional grating or multiple one-dimensional or two-dimensional gratings.

[0079] Optionally, the coupling region 102 may be composed of a single two-dimensional grating or multiple one-dimensional or two-dimensional gratings.

[0080] In some examples of this application, the metal layer 200 may be formed in the coupling region 101 by deposition, including atomic layer deposition (ALD), physical vapor deposition (PVD), high-temperature chemical vapor deposition (CVD), or plasma-enhanced chemical vapor deposition (PECVD).

[0081] According to the formation method of the metal layer 200 provided in the above example, it is advantageous to control the thickness of the metal layer 200 to be greater than 15nm.

[0082] In some examples of this application, the material of the non-metallic material layer 300 includes silicon oxide, titanium oxide, aluminum oxide, or embossing adhesive.

[0083] According to another aspect of this application, a light guide device is provided, which is manufactured using the coating method for light guide devices described above.

[0084] According to another aspect of this application, a light guide device is also provided, see [link to relevant documentation]. Figure 1 The light guide device includes a substrate 100, and a coupling region 101 and a coupling region 102 disposed on the substrate 100; the coupling region 101 is covered with at least a metal layer 200; the coupling region 102 is covered with a non-metallic material layer 300.

[0085] The light guiding device is, for example, a diffractive waveguide element, and the substrate 100 is a waveguide substrate.

[0086] The coupling region 101 is used to couple external light into the substrate 100.

[0087] The coupling region 102 is a pupil-expanding and coupling grating that expands the coupled light rays from the coupling region 101 in both the horizontal and vertical dimensions and couples the light rays out.

[0088] The coupling-in region 101 and the coupling-out region 102 can be placed on the same surface of the substrate 100 or distributed on different surfaces in any arrangement or combination.

[0089] For the entire light guide device, the coupling grating in the coupling region 101 and the coupling grating in the coupling region 102 constitute a closed grating vector polygon. The coupling region 101 can be composed of a single one-dimensional or two-dimensional grating or multiple one-dimensional or two-dimensional gratings. The coupling region 102 can be composed of a single two-dimensional grating or multiple one-dimensional or two-dimensional gratings.

[0090] According to another aspect of this application, embodiments of this application also provide a head-mounted display device. The head-mounted display device includes a housing and a light guide device as described above.

[0091] The light guiding device is, for example, a diffractive waveguide element, which is disposed within the housing.

[0092] In the embodiments of this application, the head-mounted display device may be AR glasses or MR glasses, and it also includes an image source that provides incident light to the light guide device. When the incident light is incident on the light guide device from the air medium, it first passes through the diffraction of the coupling region 101, then enters the substrate 100, is transmitted through total internal reflection, and then passes out from the coupling region 102 and enters the human eye.

[0093] The specific implementation of the head-mounted display device in this application can refer to the coating method of the light guide device and the various embodiments of the light guide device described above. Therefore, it has at least all the beneficial effects brought about by the technical solutions of the above embodiments, and will not be described in detail here.

[0094] The above embodiments mainly describe the differences between the various embodiments. As long as the different optimization features between the various embodiments are not contradictory, they can be combined to form a better embodiment. For the sake of brevity, they will not be elaborated here.

[0095] While specific embodiments of this application have been described in detail by way of examples, those skilled in the art should understand that the above examples are for illustrative purposes only and are not intended to limit the scope of this application. Those skilled in the art should understand that modifications can be made to the above embodiments without departing from the scope and spirit of this application. The scope of this application is defined by the appended claims.

Claims

1. A coating method for a light guide device, characterized in that, include: A substrate is provided, and a coupling-in region and a coupling-out region are formed on the substrate; While shielding the coupling-out region, a metal layer is formed on the coupling-in region, and the thickness of the metal layer is controlled to be 16 nm to 95 nm; and Without obscuring the coupling region, a non-metallic material layer is formed on the substrate, and the non-metallic material layer at least covers the coupling region; The coupling region includes a coupling grating, and the structure of the metal layer corresponds to the structure of the coupling grating.

2. The coating method for the light guide device according to claim 1, characterized in that, The metal layer may be made of aluminum, gold, copper or silver.

3. The coating method for the light guide device according to claim 1, characterized in that, The metal layer is further covered with the non-metallic material layer; The coupling region includes a coupling grating and a non-metallic material layer covering the coupling grating, and the coupling grating and the coupling grating form a closed grating vector polygon.

4. The coating method for the light guide device according to any one of claims 1-3, characterized in that, The metal layer is formed in the coupling region by deposition, including atomic layer deposition (ALD), physical vapor deposition (PVD), high-temperature chemical vapor deposition (CVD), or plasma-enhanced chemical vapor deposition (PECVD).

5. The coating method for the light guide device according to claim 1, characterized in that, The material of the non-metallic material layer includes silicon dioxide, titanium dioxide, aluminum oxide, or embossing adhesive.

6. A light guide device, characterized in that, It is manufactured using the coating method of any one of claims 1-5 for the light guide device.

7. A light guide device, characterized in that, It includes a substrate (100), and a coupling region (101) and a coupling region (102) disposed on the substrate (100). The coupling region (101) is at least covered with a metal layer (200). The coupling region (102) is covered with a non-metallic material layer (300). The thickness of the metal layer (200) is controlled to be 16nm~95nm; The coupling region (101) includes a coupling grating, and the structure of the metal layer (200) corresponds to the structure of the coupling grating.

8. A head-mounted display device, characterized in that, include: The shell; and, The light guide device as described in claim 6 or 7.

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