Head mounted display device and method of manufacturing the same

Abstract

The invention relates to a head-mounted display device and a manufacturing method thereof. The head-mounted display device includes an optical machine, a frame, an optical waveguide assembly, a reflective element, and an adhesion structure. The optical machine and the optical waveguide assembly are arranged in the mirror frame. The reflecting element is stacked on the optical waveguide assembly, the reflecting element comprises a transparent substrate, a first reflecting film and a second reflecting film, and the first reflecting film and the second reflecting film are arranged on the two opposite surfaces of the transparent substrate respectively. The adhesion structure is arranged on one side, back to the optical waveguide assembly, of the reflection element, and the adhesion structure is used for adhering the reflection element and the optical machine or adhering the reflection element and the optical frame. The head-mounted display device can give consideration to miniaturization and good optical performance.

Description

Technical Field

[0001] The present application relates to the technical field of head-mounted display devices, and in particular to a head-mounted display device and a manufacturing method thereof. Background Art

[0002] Head-mounted display devices such as virtual reality (VR) devices, augmented reality (AR) devices, and mixed reality (MR) devices usually include a diffractive optical waveguide module to conduct the light emitted by the light engine to the user's eyes. Compared with other methods such as geometric optical waveguides and free-form surface modules, the use of diffractive optical waveguides can effectively reduce the size and weight of the head-mounted display device. However, with the improvement of user requirements, the requirements for the miniaturization and optical performance of head-mounted display devices are also getting higher and higher. Currently, it is difficult for head-mounted display devices to balance miniaturization and good optical performance. Summary of the Invention

[0003] Embodiments of the present application provide a head-mounted display device and a manufacturing method thereof to solve the problem that currently it is difficult for head-mounted display devices to balance miniaturization and good optical performance.

[0004] A head-mounted display device includes:

[0005] A spectacle frame, a light engine, and an optical waveguide assembly, where the light engine and the optical waveguide assembly are disposed in the spectacle frame;

[0006] A reflection element stacked on the optical waveguide assembly, the reflection element including a transparent substrate, a first reflection film, and a second reflection film, where the first reflection film and the second reflection film are respectively disposed on two opposite surfaces of the transparent substrate; and,

[0007] An adhesion structure disposed on a side of the reflection element facing away from the optical waveguide assembly, the adhesion structure being used to adhere the reflection element to the light engine or to adhere the reflection element to the spectacle frame.

[0008] The above-mentioned head-mounted display device arranges the adhesion structure on the optical waveguide component for the optical waveguide component to adhere to other components such as the optical engine or the spectacle frame, rather than adhering to other components through a cover plate arranged on one side of the optical waveguide component, which is beneficial to saving the setting of the cover plate, thereby being beneficial to compressing the size of the head-mounted display device. Moreover, a reflective element is arranged between the adhesion structure and the optical waveguide component, and the reflective element can reflect the light incident on the reflective element in the optical waveguide component back to the optical waveguide component, avoiding the light from emitting from the adhesion structure or being absorbed by the adhesion structure. Thus, while reducing the size of the head-mounted display device, the light utilization efficiency of the optical waveguide component can be improved, and the optical performance such as the brightness uniformity and color uniformity of the head-mounted display device can be enhanced, so that the head-mounted display device can take into account miniaturization and good optical performance. In addition, a transparent substrate is arranged in the reflective element. The first reflective film and the second reflective film can be arranged on the transparent substrate first, and then the reflective element is arranged on the optical waveguide component, which can avoid directly preparing the reflective film on the optical waveguide component with a lower heat distortion temperature through a high-temperature process, thereby avoiding the deformation of the optical waveguide component due to too high temperature during the coating process, which is beneficial to further improving the optical performance of the head-mounted display device. And because there is a transparent substrate, reflective films can be arranged on both opposite sides of the transparent substrate to improve the reflectivity of the reflective element to light, so that more light incident on the reflective element from the optical waveguide component can be reflected back to the optical waveguide component, which is also beneficial to further improving the optical performance of the head-mounted display device.

[0009] A manufacturing method of a head-mounted display device includes:

[0010] Respectively arrange a first reflective film and a second reflective film on two opposite surfaces of the transparent substrate to form a reflective element;

[0011] Attach the reflective element to the waveguide sheet;

[0012] Apply glue on the side of the reflective element facing away from the waveguide sheet to form an adhesion structure;

[0013] Attach the optical engine or the lens frame to the adhesion structure. By using the manufacturing method of the above-mentioned head-mounted display device, the adhesion structure is arranged on the waveguide for the waveguide to adhere to other components such as the optical engine or the lens frame, which is beneficial to reducing the size of the head-mounted display device. Moreover, a reflective element is arranged between the adhesion structure and the waveguide. The reflective element can reflect the light incident on the reflective element in the waveguide back to the waveguide, avoiding the light from emitting from the adhesion structure or being absorbed by the adhesion structure. Thus, while reducing the size of the head-mounted display device, the light utilization efficiency of the waveguide can be improved, and the optical performance such as the brightness uniformity and color uniformity of the head-mounted display device can be enhanced. Furthermore, the head-mounted display device can achieve both miniaturization and good optical performance. In addition, a transparent substrate is arranged in the reflective element. The first reflective film and the second reflective film can be arranged on the transparent substrate first, and then the reflective element is arranged on the waveguide, which can avoid directly preparing the reflective film on the waveguide with a relatively low heat distortion temperature through a high-temperature process, thereby avoiding the deformation of the waveguide due to excessive temperature during the coating process, which is beneficial to further improving the optical performance of the head-mounted display device. And, due to the presence of the transparent substrate, reflective films can be arranged on both opposite sides of the transparent substrate to improve the reflectivity of the reflective element to light, so that more light incident on the reflective element from the waveguide can be reflected back to the waveguide, which is also beneficial to further improving the optical performance of the head-mounted display device. Description of the Drawings

[0014] To more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, the following will briefly introduce the drawings required for the description of the embodiments or the prior art. Obviously, the drawings in the following description are only some embodiments of the present application. For those of ordinary skill in the art, other drawings can be obtained based on these drawings without creative efforts.

[0015] Figure 1 It is a schematic optical path diagram of the light emitted from the interface between the optical waveguide and the glue in a traditional head-mounted display device.

[0016] Figure 2 It is a schematic structural diagram of a head-mounted display device in some embodiments.

[0017] Figure 3 It is a schematic external structural diagram of a head-mounted display device in some embodiments.

[0018] Figure 4 It is a schematic structural diagram of a head-mounted display device with two groups of optical waveguide components in some embodiments.

[0019] Figure 5 For Figure 2 The schematic structural diagram of some components of the head-mounted display device shown.

[0020] Figure 6 Schematic structural diagram of a head-mounted display device in some other embodiments.

[0021] Figure 7 is Figure 6 Schematic structural diagram of some components of the head-mounted display device shown.

[0022] Figure 8 Schematic structural diagram of a reflective element including a transparent substrate in some embodiments.

[0023] Figure 9 Schematic structural diagram of a sleeve provided with a notch in some embodiments.

[0024] Figure 10 Schematic structural diagram of a reflective element including a transparent substrate in some other embodiments.

[0025] Reference numerals:

[0026] 1, optical waveguide; 2, glue;

[0027] 10, head-mounted display device; 11, optical engine; 111, sleeve; 1111, notch; 112, light-emitting part; 12, optical waveguide assembly; 121, waveguide sheet; 122, first surface; 123, second surface; 124, input grating; 125, output grating; 13, frame; 14, reflective element; 141, first reflective film; 142, second reflective film; 143, first protective film; 144, second protective film; 145, transparent substrate; 146, optical glue layer; 15, adhesion structure; 16, cover plate; 17, third optical waveguide assembly; 171, third waveguide sheet; 172, third input grating; 173, third output grating; 18, bracket; 191, glue; 21, spectacle frame. Detailed implementation manners

[0028] For the convenience of understanding the present application, the present application will be described more comprehensively below with reference to the relevant drawings. Preferred embodiments of the present application are shown in the drawings. However, the present application can be implemented in many different forms and is not limited to the embodiments described herein. On the contrary, these embodiments are provided to make the understanding of the disclosure of the present application more thorough and comprehensive.

[0029] In traditional head-mounted display devices, an optical waveguide is usually provided to conduct the light emitted by the optical engine. When the light is conducted in the optical waveguide, if the light hits the interface between the optical waveguide and the air, since the refractive index of the material of the optical waveguide itself is much greater than that of the air, the light is likely to reach the total reflection critical angle at the interface between the optical waveguide and the air and undergo total reflection, thus having a high light transmission efficiency. In traditional head-mounted display devices, protective cover plates are usually required to be provided on both opposite sides of the optical waveguide. The optical engine is glued to the protective cover plates, and both protective cover plates on both sides are spaced apart from the optical waveguide, which can not only provide protection for the optical waveguide but also ensure that both sides of the optical waveguide are air media, thereby increasing the total reflection probability of the light at the interface between the optical waveguide and the air, improving the light transmission efficiency of the optical waveguide, and further improving the optical performance of the head-mounted display device. However, the setting of the protective cover plates on both sides of the optical waveguide will increase the size of the head-mounted display device, which is not conducive to the miniaturization of the head-mounted display device.

[0030] Reference Figure 1 As shown, if one of the protective cover plates of the optical waveguide 1 is omitted in order to compress the size of the head-mounted display device, the optical engine is directly adhered to the optical waveguide 1 through the glue 2. Since the refractive index of the glue 2 is usually greater than that of the air, the total reflection critical angle of the light at the interface between the optical waveguide 1 and the glue 2 is much greater than the total reflection critical angle of the light at the interface between the optical waveguide 1 and the air, which easily leads to a decrease in the total reflection probability of the light at the interface between the optical waveguide 1 and the glue 2, and some light is likely to refract and transmit through the glue 2. When the glue 2 is a black glue 2, the glue 2 may also absorb the light hitting the interface between the glue 2 and the optical waveguide 1, thereby causing a decrease in the light transmission efficiency of the optical waveguide 1, resulting in a decrease in the color uniformity and brightness uniformity of the head-mounted display device and affecting the optical performance of the head-mounted display device. Therefore, it is difficult for traditional head-mounted display devices to balance miniaturization and good optical performance.

[0031] To solve the above problems, the present application provides a head-mounted display device and a manufacturing method thereof.

[0032] Please refer to Figures 2 to 5 , Figure 2 which is a schematic structural diagram of the head-mounted display device 10 in some embodiments, Figure 3 which is an external structural diagram of the head-mounted display device 10 in some embodiments, Figure 4 which is a schematic structural diagram of the head-mounted display device provided with two groups of optical waveguide components 12 in some embodiments. Figure 5Schematic diagram of the structure of some components of the head-mounted display device 10 in some embodiments. The head-mounted display device 10 provided in the present application includes, but is not limited to, VR devices, AR devices, MR devices, etc. The head-mounted display device 10 may include a frame 21, an optical engine 11, an optical waveguide assembly 12, and a spectacle frame 13. The optical engine 11 is capable of emitting light, and the light emitted by the optical engine 11 can be coupled into the optical waveguide assembly 12 and then coupled out and emitted to the user's eyes after being conducted by the optical waveguide assembly 12. The spectacle frame 13 can be used as a support member of the head-mounted display device 10 to provide structural support and protection for the optical waveguide assembly 12 and the optical engine 11. The frame 21 is connected to the spectacle frame 13 and can wear the spectacle frame 13 on the user's head.

[0033] Combined with Figure 2 、 Figure 4 and Figure 5 As shown, in some embodiments, the head-mounted display device 10 further includes a reflection element 14 and an adhesion structure 15. The reflection element 14 is disposed on the surface of the optical waveguide assembly 12, and the adhesion structure 15 is disposed on the side of the reflection element 14 facing away from the optical waveguide assembly 12 for adhering the optical waveguide assembly 12 to other components. For example, the optical engine 11 or the spectacle frame 13 of the head-mounted display device 10 can be adhered to the optical waveguide assembly 12 through the adhesion structure 15.

[0034] Combined with Figure 2 and Figure 4 As shown, in some embodiments, the head-mounted display device 10 may be provided with two sets of optical waveguide assemblies 12. Reflection elements 14 can be provided on both sets of optical waveguide assemblies 12, and adhesion structures 15 can be provided on both sets of optical waveguide assemblies 12 to adhere to other components such as the optical engine 11. Both sets of optical waveguide assemblies 12 and two optical engines 11 are accommodated in the spectacle frame 13. The two sets of optical waveguide assemblies 12 can be in a symmetric structure to project light to the two eyeballs of the user respectively. It can be understood that Figure 2 only shows one set of the optical waveguide assemblies 12 of the head-mounted display device 10 and a partial structure of the spectacle frame 13.

[0035] The above-mentioned head-mounted display device 10 arranges the adhesion structure 15 on the optical waveguide component 12 for the optical waveguide component 12 to adhere to other components such as the optical engine 11 or the spectacle frame 13, rather than adhering to other components through the cover plate 16 arranged on one side of the optical waveguide component 12. This can save the setting of the cover plate 16 on one side of the optical waveguide component 12, thus facilitating the compression of the size of the head-mounted display device 10. Moreover, a reflection element 14 is arranged between the adhesion structure 15 and the optical waveguide component 12. The reflection element 14 can reflect the light incident on the reflection element 14 in the optical waveguide component 12 back to the optical waveguide component 12, avoiding the light from emitting from the adhesion structure 15 or being absorbed by the adhesion structure 15. Therefore, while reducing the size of the head-mounted display device 10, the light utilization efficiency of the optical waveguide component 12 can be improved, and the optical performance such as the brightness uniformity and color uniformity of the head-mounted display device 10 can be enhanced. Furthermore, the head-mounted display device 10 can achieve both miniaturization and good optical performance.

[0036] In some embodiments, the optical waveguide component 12 is a first optical waveguide component. The first optical waveguide component includes a waveguide sheet 121, an input grating 124, and an output grating 125. The waveguide sheet 121 has a first surface 122 and a second surface 123 arranged opposite to each other. The input grating 124 and the output grating 125 are arranged at intervals on the first surface 122, and the reflection element 14 is arranged on the second surface 123. The light emitted by the optical engine 11 can enter the waveguide sheet 121 from the input grating 124 and be conducted in the waveguide sheet 121 to the output grating 125, so as to emit from the output grating 125 of the optical waveguide component 12 for the user to view. It can be understood that the adhesion structure 15 can adhere to the optical engine 11 or the spectacle frame 13 on the side of the reflection element 14 facing away from the waveguide sheet 121, so that the head-mounted display device 10 does not need to arrange a cover plate 16 on the second surface 123 side of the waveguide sheet 121 to adhere to the optical engine 11 or the spectacle frame 13. Thus, the cover plate 16 on the side where the second surface 123 of the waveguide sheet 121 is located can be omitted, which is conducive to reducing the size of the head-mounted display device 10.

[0037] In some embodiments, the head-mounted display device 10 may further include a cover plate 16 disposed on the side where the first surface 122 of the waveguide plate 121 is located. The cover plate 16 is spaced apart from the optical waveguide assembly 12, and the air medium is between the cover plate 16 and the optical waveguide assembly 12. Thus, while the head-mounted display device 10 saves the cover plate 16 on the side where the second surface 123 of the waveguide plate 121 is located to compress the size of the head-mounted display device 10, the cover plate 16 on the side of the first surface 122 of the waveguide plate 121 can encapsulate the side of the waveguide plate 121 where the coupling grating 124 and the decoupling grating 125 are provided, so as to provide protection for the coupling grating 124 and the decoupling grating 125. Moreover, the setting of the air medium between the cover plate 16 and the optical waveguide assembly 12 can also increase the total reflection probability of the light in the waveguide plate 121 on the first surface 122, thereby improving the light utilization efficiency and optical performance of the head-mounted display device 10. Thus, the above-mentioned head-mounted display device 10 can effectively balance miniaturization, good imaging quality, and good structural reliability.

[0038] Combined Figure 2 and Figure 5 As shown, in some embodiments, the optical waveguide assembly 12 is a reflective diffraction optical waveguide, both the coupling grating 124 and the decoupling grating 125 are reflective diffraction gratings, the optical engine 11 is disposed on the side where the second surface 123 of the waveguide plate 121 is located, the optical engine 11 includes a sleeve 111 and a light-emitting part 112 disposed in the sleeve 111, and the sleeve 111 of the optical engine 11 is adhered to the adhesion structure 15. In this embodiment, the light emitted by the light-emitting part 112 of the optical engine 11 passes through the waveguide plate 121 and reaches the coupling grating 124, and is coupled into the waveguide plate 121 by the coupling grating 124, and is conducted in the waveguide plate 121 in a reflective form to the decoupling grating 125, and then is coupled out of the waveguide plate 121 by the decoupling grating 125.

[0039] Refer to Figure 5As shown, it can be understood that in this embodiment, when light is coupled into the grating 124 and then coupled into the waveguide sheet 121, if the light hits the part of the second surface 123 outside the reflecting element 14, that is, when it hits the interface between the waveguide sheet 121 and the air medium, since the refractive index of the waveguide sheet 121 is much higher than that of the air medium. For example, the refractive index of air can be 1, and the refractive index of the waveguide sheet 121 can be 1.6 - 2.0, such as a resin wafer material with a refractive index of 1.7. Light is likely to undergo total internal reflection at the interface between the waveguide sheet 121 and the air medium, and the light transmission efficiency is high. When the light hits the interface between the waveguide sheet 121 and the reflecting element 14, although the refractive index of the adhesion structure 15 is higher than that of air, for example, the refractive index of the adhesion structure 15 can be 1.5, light is not likely to undergo total internal reflection at the interface between the adhesion structure 15 and the waveguide sheet 121. However, due to the arrangement that the reflecting element 14 separates the waveguide sheet 121 from the adhesion structure 15, the reflecting element 14 can reflect the light back into the waveguide sheet 121, preventing the light from refracting out of the adhesion structure 15 or being absorbed by the adhesion structure 15. Thus, when the optical waveguide assembly 12 is adhered to the optical engine 11 through the adhesion structure 15 to save the cover plate 16 on the side where the second surface 123 of the waveguide sheet 121 is located, the light transmission efficiency can be effectively improved, enabling the head-mounted display device 10 to maintain good optical performance.

[0040] In some embodiments, the projection of the part of the sleeve 111 of the optical engine 11 adhered to the optical waveguide assembly 12 on the first surface 122 surrounds the coupling grating 124, and the projection of the reflecting element 14 on the first surface 122 surrounds at least part of the contour of the coupling grating 124. In some embodiments, the projection of the reflecting element 14 on the first surface 122 is offset from the coupling grating 124. For example, the projection of the reflecting element 14 on the first surface 122 extends around at least part of the contour of the coupling grating 124 and has no overlapping part with the coupling grating 124. Thus, while setting the reflecting element 14 to improve the light transmission efficiency, it can also prevent the reflecting element 14 from blocking the light emitted by the optical engine 11 from hitting the coupling grating 124, which is also beneficial to improving the light utilization efficiency of the head-mounted display device 10.

[0041] It can be understood that although the reflection effect of the reflection surface of the reflection element 14 on light is higher than that of the interface between the waveguide sheet 121 and the adhesion structure 15 when the waveguide sheet 121 is in direct contact with the adhesion structure 15, the reflection effect of the reflection element 14 on light is still lower than total reflection. Therefore, while ensuring that the reflection element 14 can effectively separate the waveguide sheet 121 and the adhesion structure 15, the coverage area of the reflection element 14 on the second surface 123 should be as small as possible, so that more light incident on the second surface 123 is incident on the interface between the waveguide sheet 121 and the air medium and is transmitted in the form of total reflection, thereby maximizing the light transmission efficiency. Based on this, in some embodiments, the width of the reflection element 14 is greater than or equal to 1 mm and less than or equal to 3 mm. The reflection element 14 is disposed around at least part of the contour of the coupling grating 124, and the projection of the reflection element 14 on the first surface 122 may be generally annular or a part of an annulus. The width of the reflection element 14 can be understood as the dimension of the reflection element 14 in the radial direction of the annulus. Thus, on the one hand, the reflection element 14 can have a sufficient coverage area for the adhesion structure 15 to be disposed, so as to improve the bonding strength between the optical engine 11 or other components and the optical waveguide assembly 12 and enhance the structural stability of the head-mounted display device 10. On the other hand, the coverage area of the reflection element 14 will not be too large, which is beneficial to improving the light transmission efficiency of the optical waveguide assembly 12.

[0042] In this embodiment, the reflection element 14 can be disposed around the coupling grating 124 to be generally annular, and the projection of the part where the sleeve 111 is adhered to the optical waveguide assembly 12 on the second surface 123 can be completely located within the reflection element 14. Of course, after the light emitted by the optical engine 11 is coupled into the waveguide sheet 121 by the coupling grating 124, the light generally conducts from the position where the coupling grating 124 is located to the side where the coupling-out grating 125 is located, and less light is incident on the part of the second surface 123 that is away from the coupling-out grating 125 and near the coupling grating 124. Therefore, referring to Figure 2 As shown, in some embodiments, the reflection element 14 can also be only disposed on the part of the second surface 123 that is near the coupling-out grating 125 and near the coupling grating 124. At this time, the part of the glue for adhering the sleeve 111 to the optical waveguide assembly 12 that is located on the reflection element 14 can be regarded as the adhesion structure 15 of the present application, and the part of the glue that is located outside the reflection element 14 is used to improve the adhesion strength between the sleeve 111 and the optical waveguide assembly 12.

[0043] Referring to Figure 2As shown, in this embodiment, the lens frame 13 of the head mounted display device 10 can be adhered to the cover plate 16 by glue 191 on the side of the cover plate 16 facing away from the optical waveguide assembly 12, so as to provide support and protection for components such as the optical waveguide assembly 12, the cover plate 16 and the optical machine 11. Of course, a larger number of optical waveguide assemblies can be provided in the head mounted display device 10, and the refractive indexes of different optical waveguide assemblies can be the same or different, and different optical waveguide assemblies can be used to transmit light of different wavelengths to meet different light transmission requirements.

[0044] In some embodiments, the head mounted display device 10 further includes a third optical waveguide component 17, which is disposed between the optical waveguide component 12 and the cover plate 16, and includes a third waveguide plate 171, a third coupling-in grating 172, and a third coupling-out grating 173, wherein the third coupling-in grating 172 and the third coupling-out grating 173 are both disposed on the side of the third waveguide plate 171 facing away from the optical waveguide component 12. The third optical waveguide component 17, the optical waveguide component 12, and the cover plate 16 are all spaced apart so that the two opposite surfaces of the third waveguide plate 171 are in contact with the air medium, thereby increasing the probability of total reflection of light in the third waveguide plate 171, thereby increasing the light transmission efficiency of the head mounted display device 10. Figure 2 In the illustrated embodiment, the third optical waveguide component 17 may also be a reflective diffraction optical waveguide, and the third coupling-in grating 172 and the third coupling-out grating 173 are both reflective diffraction gratings. The optical waveguide component 12, the third optical waveguide component 17 and the cover plate 16 may be connected to each other via a bracket 18. Part of the light emitted by the optical engine 11 can sequentially pass through the waveguide plate 121, the coupling-in grating 124 and the third waveguide plate 171 to the third coupling-in grating 172, and is coupled by the third coupling-in grating 172 to be injected into the third waveguide plate 171, and is transmitted to the third coupling-out grating 173 by total reflection in the third waveguide plate 171, and is coupled by the third coupling-out grating 173 to be injected out of the third waveguide plate 171.

[0045] Further, in some embodiments, when the optical engine 11 is adhered to the optical waveguide assembly 12 through the adhesion structure 15 provided on the reflective element 14, the adhesion structure 15 can be black glue 191. In a conventional head-mounted display device, the provision of black glue 191 is likely to absorb the light of the optical waveguide assembly 12 and reduce the light utilization efficiency. In this embodiment, since the provision of the reflective element 14 can separate the adhesion structure 15 from the optical waveguide assembly 12, the light transmission efficiency will not be reduced even if the adhesion structure 15 is provided as black glue 191. The provision of black glue 191 can absorb the light emitted between the sleeve 111 and the optical waveguide assembly 12, and prevent the light emitted by the optical engine 11 from leaking out of the gap between the sleeve 111 and the optical waveguide assembly 12 to generate stray light, which is beneficial to improving the imaging quality of the head-mounted display device 10.

[0046] It should be noted that in the above embodiments, the optical waveguide component 12 can be a reflective diffraction optical waveguide, while in the following embodiments, corresponding Figure 6 , Figure 7 and Figure 10 in the embodiments shown, the optical waveguide component 12 can be a transmissive diffraction optical waveguide. In this application, when the optical waveguide component 12 is a reflective diffraction optical waveguide, the optical waveguide component 12 can be referred to as the first optical waveguide component, and when the optical waveguide component 12 is a transmissive optical waveguide, the optical waveguide component 12 can be referred to as the second optical waveguide component.

[0047] Please refer to Figure 6 and Figure 7 , in some other embodiments, the optical waveguide component 12 is the second optical waveguide component. The second optical waveguide component can be a transmissive diffraction optical waveguide. The second optical waveguide component includes an input grating 124 and an output grating 125. Both the input grating 124 and the output grating 125 are transmissive diffraction gratings. The optical engine 11 is disposed on the side where the first surface 122 of the waveguide sheet 121 is located, and the frame 13 is adhesively connected to the optical waveguide component 12 through an adhesive structure 15 on the side where the second surface 123 of the waveguide sheet 121 is located. The light emitted by the optical engine 11 can be incident on the input grating 124 and be coupled into the waveguide sheet 121 by the input grating 124, and then conducted in the waveguide sheet 121 to the output grating 125, so as to be coupled and emitted from the waveguide sheet 121 by the output grating 125. Referring to Figure 7 shown, it can be understood that after the light is coupled into the waveguide sheet 121 by the input grating 124, if the light is incident on the interface between the waveguide sheet 121 and the reflective element 14, although the refractive index of the adhesive structure 15 is higher than that of air and the light is not likely to undergo total internal reflection at the interface between the waveguide sheet 121 and the adhesive structure 15, due to the setting of the reflective element 14, the reflective surface of the reflective element 14 can reflect the light incident on the reflective element 14 back into the waveguide sheet 121, avoiding the light from refracting and emitting from the adhesive structure 15 or being absorbed by the adhesive structure 15. Thus, while the optical waveguide component 12 is adhesively connected to the frame 13 through the adhesive structure 15 to save the cover plate 16 on the side of the waveguide sheet 121 facing the frame 13, the light transmission efficiency can be effectively improved, enabling the head-mounted display device 10 to maintain good optical performance.

[0048] In Figure 6In the illustrated embodiment, the head-mounted display device 10 may include a cover plate 16 disposed on the side where the first surface 122 of the waveguide plate 121 is located. The cover plate 16 is spaced apart from the optical waveguide assembly 12, and an air medium is formed between the cover plate 16 and the optical waveguide assembly 12. The light engine 11 may be disposed on the side of the cover plate 16 facing away from the optical waveguide assembly 12 and adhered to the cover plate 16. Thus, the cover plate 16 can encapsulate the first surface 122 of the optical waveguide assembly 12, thereby providing protection for the coupling grating 124 and the coupling grating 172, and can also provide structural support for the light engine 11. Moreover, the setting of the air medium between the cover plate 16 and the optical waveguide assembly 12 can also increase the total reflection probability of the light in the waveguide plate 121 on the first surface 122, thereby improving the light utilization efficiency and optical performance of the head-mounted display device 10. Thus, the above-mentioned head-mounted display device 10 can effectively balance miniaturization, good imaging quality, and good structural reliability.

[0049] In this embodiment, the optical waveguide assembly 12 may also include a third optical waveguide assembly 17. The third optical waveguide assembly 17 is disposed between the first optical waveguide assembly (or the second optical waveguide assembly) and the cover plate 16. The third optical waveguide assembly 17 includes a third waveguide plate 171, a third coupling grating 172, and a third coupling-out grating 173. The third coupling grating 172 and the third coupling-out grating 173 are disposed on the side of the third waveguide plate 171 facing the light engine 11. The third optical waveguide assembly 17 may be a transmissive diffraction optical waveguide, and both the third coupling grating 172 and the third coupling-out grating 173 are transmissive diffraction gratings. A part of the light emitted by the light engine 11 can be incident on the third coupling grating 172 and be coupled into the third waveguide plate 171 by the third coupling grating 172. Another part of the light emitted by the light engine 11 can sequentially pass through the third coupling grating 172 and the third waveguide plate 171 and be incident on the coupling grating 124, so as to be coupled into the waveguide plate 121 by the coupling grating 124.

[0050] In Figure 7 In the illustrated embodiment, the coverage area of the reflection element 14 on the second surface 123 is not limited as long as the reflection element 14 can provide a sufficient dispensing area for the adhesion structure 15 to improve the adhesion strength between the adhesion structure 15 and the frame 13, and can separate the adhesion structure 15 from the waveguide plate 121 to improve the light transmission efficiency of the optical waveguide assembly 12. In some embodiments, the projection of the reflection element 14 on the first surface 122 at least covers the area where the coupling grating 124 is located.

[0051] In some embodiments, the adhesion structure 15 may be any suitable glue.

[0052] It should be noted that in Figures 1 to 7In the illustrated embodiment, when the reflective element 14 is a coating layer disposed on the waveguide sheet 121, such as a silver coating or an aluminum coating, the reflectivity of the single-layer coating layer of the reflective element 14 for the entire wavelength band is usually between 85% and 90%. Relative to total reflection, there is usually a 10%-15% light loss when light is reflected at the interface between the waveguide sheet 121 and the reflective element 14. Therefore, the optical performance of the head-mounted display device 10 still needs to be improved. At the same time, the material of the waveguide sheet 121 is usually a resin wafer or the like, and the heat distortion temperature of the waveguide sheet 121 is usually only about 80°C. When directly coating the waveguide sheet 121 to form the reflective element 14, the coating process is usually a high-temperature process. For example, the temperature of the coating process is usually higher than 80°C, and local warping and deformation of the waveguide sheet 121 are likely to occur during the coating process due to excessive temperature, resulting in a decrease in the MTF value of the head-mounted display device and affecting the optical performance of the head-mounted display device 10.

[0053] Combined Figure 2 with Figure 8 As shown, to solve the above problems, in some embodiments, the reflective element 14 includes a transparent substrate 145, a first reflective film 141, and a second reflective film 142. The first reflective film 141 and the second reflective film 142 are respectively disposed on the surfaces of the transparent substrate 145 facing the optical waveguide assembly 12 and facing away from the optical waveguide assembly 12, that is, on the two opposite surfaces of the transparent substrate 145. The first reflective film 141 and the second reflective film 142 can both be any applicable reflective film layers such as silver coatings or aluminum coatings plated on the transparent substrate 145.

[0054] In the above-mentioned head-mounted display device 10, by providing a transparent substrate 145 in the reflective element 14, the first reflective film 141 and the second reflective film 142 can be first disposed on the transparent substrate 145, and then the reflective element 14 can be disposed on the optical waveguide assembly 12, which can avoid directly preparing the reflective film on the optical waveguide assembly 12 with a low heat distortion temperature through a high-temperature process, thereby avoiding deformation of the optical waveguide assembly 12 due to excessive temperature during the coating process, which is beneficial to further improving the optical performance of the head-mounted display device 10. Moreover, due to the provision of the transparent substrate 145, reflective films can be provided on both opposite sides of the transparent substrate 145. The first reflective film 141 and the second reflective film 142 cooperate with each other, which can effectively improve the reflectivity of the reflective element 14 to light. For example, the reflectivity of the reflective element 14 can be increased to more than 97%, so that more light incident on the reflective element 14 from the optical waveguide assembly 12 can be reflected back to the optical waveguide assembly 12, which is also beneficial to further improving the optical performance of the head-mounted display device 10.

[0055] When the reflective element 14 is a structure such as a silver coating or an aluminum coating that is easily corroded, referring to Figure 8As shown, in some embodiments, the head-mounted display device 10 further includes a first protective film 143 and a second protective film 144. The first protective film 143 and the second protective film 144 are respectively disposed on the side of the first reflective film 141 and the second reflective film 142 facing away from the transparent substrate 145, that is, between the waveguide plate 121 and the first reflective film 141, and between the second reflective film 142 and the adhesion structure 15. The first protective film 143 covers at least a part of the surface of the first reflective film 141 facing the waveguide plate 121, and the second protective film 144 covers at least a part of the surface of the second reflective film 142 facing away from the transparent substrate 145, so as to provide a protective effect on the reflective element 14, maintain the optical performance stability of the reflective element 14, and prevent the reflective element 14 from being corroded and causing a decrease in reflectivity. The first protective film 143 and the second protective film 144 include, but are not limited to, a screen printing ink layer, or a dense film layer such as a silicon dioxide film layer or an aluminum oxide film layer, as long as they can provide a protective effect on the reflective element 14.

[0056] It can be understood that when the protective film is a screen printing ink layer, due to the possible overflow of the screen printing ink, in order to prevent the screen printing ink from overflowing outside the first reflective film 141 and the second reflective film 142 and contacting the optical waveguide assembly 12, resulting in the light absorption of the screen printing ink reducing the light transmission efficiency of the optical waveguide assembly 12, when setting the screen printing ink, the screen printing ink can be recessed 0.1 mm - 0.3 mm relative to the contour of the reflective element 14 to reserve an overflow space. When the first protective film 143 and the second protective film 144 are dense film layers such as a silicon dioxide film layer or an aluminum oxide film layer, since the protective film is not easily extended outside the first reflective film 141 and the second reflective film 142 during setting, the first protective film 143 and the second protective film 144 can respectively overlap with the first reflective film 141 and the second reflective film 142 to cover the entire surfaces of the first reflective film 141 and the second reflective film 142, improving the protective effect of the first protective film 143 and the second protective film 144 on the first reflective film 141 and the second reflective film 142, thereby improving the optical performance stability of the reflective element 14.

[0057] In some embodiments, the heat distortion temperature of the transparent substrate 145 is higher than that of the waveguide sheet 121. Using the transparent substrate 145 with a higher heat distortion temperature as the bearing structure for the first reflective film 143 and the second reflective film 144 is conducive to reducing the probability of deformation of the transparent substrate 145 due to high temperature when the first protective film 143 and the second protective film 144 are provided on the transparent substrate 145 through a high-temperature process, and improving the optical performance of the head-mounted display device 10. Of course, the thickness of the transparent substrate 145 should also be small enough to avoid increasing the size of the head-mounted display device 10. In some embodiments, the thickness of the transparent substrate 145 is between 0.1 mm and 0.2 mm, which can not only have sufficient structural strength but also be conducive to the miniaturization of the head-mounted display device 10. The material of the transparent substrate 145 includes but is not limited to any suitable transparent material with a small enough thickness, a large enough heat distortion temperature, and sufficient structural strength. For example, in some embodiments, the transparent substrate 145 can use UTG (Ultra-Thin Glass) ultra-thin glass, which can reduce the thickness of the transparent substrate 145 to 0.1 mm - 0.2 mm while having sufficient structural strength, being conducive to the miniaturization of the head-mounted display device 10 and not being easily deformed during the coating process. Of course, the transparent substrate 145 can also be any other suitable transparent material, which can be specifically set according to the requirements of the heat distortion temperature and miniaturization, and will not be elaborated in this application.

[0058] In some embodiments, the head-mounted display device 10 further includes an optical adhesive layer 146. The optical adhesive layer 146 is disposed between the optical waveguide assembly 12 and the reflective element 14 to bond the optical waveguide assembly 12 and the reflective element 14. In some embodiments, the thickness of the optical adhesive layer 146 is less than 20 μm, which can reduce the position offset amount caused by refraction on the optical adhesive layer 146 when the light in the optical waveguide assembly 12 passes through the optical adhesive layer 146 and hits the reflective element 14, thereby being conducive to improving the optical performance of the head-mounted display device 10.

[0059] Combined with Figure 2 、 Figure 8 and Figure 9As shown, in some embodiments, when the reflective element 14 is disposed along a partial contour of the input grating 124, that is, when the shape of the reflective element 14 is a part of a ring, a notch 1111 may be concavely provided on the end surface of the sleeve 111 facing the optical waveguide assembly 12, and at least a part of the reflective element 14 is received in the notch 1111. With such an arrangement, the occupied space of the reflective element 14 and the entire optical engine 11 can be reduced, which is beneficial to the miniaturization of the head-mounted display device 10. The shape of the notch 1111 and its dimension in the direction perpendicular to the second surface 123 may be adapted to the shape and thickness dimension of the reflective element 14. For example, when the thickness dimension of the reflective element 14 is 0.1 mm - 0.2 mm, the end surface of the sleeve 111 may be concavely recessed by 0.1 mm - 0.2 mm, so that the reflective element 14 can be completely received in the sleeve 111 in the thickness direction, thereby ensuring that the setting of the reflective element 14 does not increase the size of the head-mounted display device 10, which is beneficial to the miniaturization of the head-mounted display device 10.

[0060] Combined Figure 6 and Figure 10 As shown, in some embodiments, when the frame 13 of the head-mounted display device 10 is adhered to the optical waveguide assembly 12 through the adhesion structure 15 provided on the reflective element 14, the reflective element 14 may also include elements such as a transparent substrate 145, a first reflective film 141, a second reflective film 142, a first protective film 143, and a second protective film 144. The reflective element 14 is adhered to the optical waveguide assembly 12 through an optical adhesive, and the second protective film 144 is adhered to the adhesion structure 15. In Figure 10 In the embodiments shown, the specific setting of the reflective element 14 can be obtained with reference to the above description and will not be elaborated here.

[0061] In some embodiments, the present application also provides a manufacturing method for the head-mounted display device 10, which can be used to manufacture the head-mounted display device 10 as described in any of the above embodiments. The manufacturing method includes:

[0062] The first reflective film 141 is provided on one surface of the transparent substrate 145 through a coating process;

[0063] The first protective film 143 is provided on the side of the first reflective film 141 facing away from the transparent substrate 145;

[0064] The second reflective film 142 is provided on the other surface of the transparent substrate 145 opposite to the first surface through a coating process;

[0065] The second protective film 144 is provided on the side of the second reflective film 142 facing away from the transparent substrate 145;

[0066] The structure formed by the transparent substrate 145, the first reflective film 141, the first protective film 143, the second reflective film 142, and the second protective film 144 is integrally cut by a laser cutting process to obtain a reflective element 14 with a suitable shape and size.

[0067] The reflective element 14 is adhered to the waveguide sheet 121 through an optical adhesive layer 146.

[0068] A bonding structure 15 is formed by applying glue on the side of the reflective element 14 facing away from the waveguide sheet 121, so that components such as the optical machine 11 or the frame 13 can be adhered to the optical waveguide assembly 12 through the bonding structure 15.

[0069] First, the first reflective film 141 and the second reflective film 142 are provided on the transparent substrate 145, and then the reflective element 14 is adhered to the waveguide sheet 121 under normal temperature process, which can avoid the deformation of the waveguide sheet 121 due to high temperature and improve the optical performance of the head-mounted display device 10. Moreover, the first reflective film 141 and the second reflective film 142 are provided on the two opposite surfaces of the transparent substrate 145, and the two reflective films cooperate to improve the reflectivity of the reflective element 14 to light, thereby improving the light utilization efficiency of the head-mounted display device 10.

[0070] It should be noted that in the step of forming the bonding structure 15 by applying glue on the side of the reflective element 14 facing away from the waveguide sheet 121, when applying glue on the reflective element 14, the glue application area can be retracted 0.5 mm - 1 mm relative to the edge of the second protective film 144 to prevent the glue from overflowing outside the reflective element 14 after glue application and affecting the appearance and optical performance of the head-mounted display device 10.

[0071] The technical features of the above-described embodiments can be combined arbitrarily. For the sake of brevity of description, not all possible combinations of the technical features in the above-described embodiments are described. However, as long as there is no contradiction in the combination of these technical features, it should be considered as the scope described in this specification.

[0072] The above-described embodiments merely represent several implementation manners of the present application, and their descriptions are relatively specific and detailed, but they should not be construed as limiting the scope of the patent application. It should be noted that for those of ordinary skill in the art, without departing from the concept of the present application, several deformations and improvements can still be made, and these all belong to the protection scope of the present application. Therefore, the protection scope of the patent of the present application should be subject to the appended claims.

Claims

1. A head-mounted display device, characterized in that, it includes: a spectacle frame, an optical engine, and an optical waveguide component, wherein the optical engine and the optical waveguide component are arranged in the spectacle frame; a reflection element stacked on the optical waveguide component, the reflection element includes a transparent substrate, a first reflection film, and a second reflection film, and the first reflection film and the second reflection film are respectively arranged on two opposite surfaces of the transparent substrate; and, an adhesion structure arranged on a side of the reflection element facing away from the optical waveguide component, and the adhesion structure is used to adhere the reflection element to the optical engine or to adhere the reflection element to the spectacle frame.

2. The head-mounted display device according to claim 1, characterized in that, both the first reflection film and the second reflection film are silver plating layers or aluminum plating layers.

3. The head-mounted display device according to claim 1, characterized in that, the thickness of the reflection element is greater than or equal to 0.1 mm and less than or equal to 0.2 mm.

4. The head-mounted display device according to claim 1, characterized in that, the head-mounted display device further includes an optical adhesive layer arranged between the optical waveguide component and the reflection element to adhere the optical waveguide component and the reflection element, and the thickness of the optical adhesive layer is less than 20 μm.

5. The head-mounted display device according to claim 1, characterized in that, the reflection element further includes a first protective film and a second protective film, and the first protective film and the second protective film are respectively arranged on sides of the first reflection film and the second reflection film facing away from the transparent substrate.

6. The head-mounted display device according to claim 1, characterized in that, the optical waveguide component includes a first optical waveguide component, the first optical waveguide component includes a waveguide sheet and a coupling grating, and the coupling grating and the reflection element are respectively arranged on two opposite surfaces of the waveguide sheet; the optical engine is arranged on a side of the optical waveguide component facing the reflection element, and a sleeve of the optical engine is adhered to the adhesion structure.

7. The head-mounted display device according to claim 6, characterized in that, a notch is recessed in an end face of the sleeve facing the first optical waveguide component, and at least a part of the reflection element is accommodated in the notch.

8. The head-mounted display device according to claim 6, characterized in that, a projection of the reflection element on a surface of the waveguide sheet where the coupling grating is arranged surrounds at least a part of the contour of the coupling grating.

9. The head-mounted display device according to claim 8, characterized in that, the width of the reflection element is greater than or equal to 1 mm and less than or equal to 3 mm.

10. The head-mounted display device according to claim 6, characterized in that, the head-mounted display device further includes a cover plate, the cover plate is arranged on a side of the waveguide sheet facing the coupling grating and is spaced apart from the first optical waveguide component, and a part of the spectacle frame is adhered to the cover plate on a side of the cover plate facing away from the first optical waveguide component.

11. The head-mounted display device according to claim 6, characterized in that, the adhesion structure includes black glue.

12. The head-mounted display device according to claim 1, wherein, the optical waveguide assembly includes a second optical waveguide assembly, the second optical waveguide assembly includes a waveguide sheet and an input grating, and the input grating and the reflection element are respectively disposed on two opposite surfaces of the waveguide sheet; at least part of the spectacle frame is disposed on one side of the optical waveguide assembly facing the reflection element and adhered to the adhesion structure.

13. The head-mounted display device according to claim 12, wherein, the head-mounted display device further includes a cover plate, the cover plate is disposed on one side of the waveguide sheet facing the input grating and is spaced from the second optical waveguide assembly, and the optical engine is disposed on one side of the cover plate facing away from the second optical waveguide assembly and adhered to the cover plate.

14. The head-mounted display device according to claim 6 or 12, wherein, the optical waveguide assembly further includes a third optical waveguide assembly, the third optical waveguide assembly is disposed on one side of the waveguide sheet of the first optical waveguide assembly or the second optical waveguide assembly facing away from the reflection element and is disposed at an interval from the first optical waveguide assembly or the second optical waveguide assembly.

15. A manufacturing method of a head-mounted display device, wherein, it includes: respectively disposing a first reflective film and a second reflective film on two opposite surfaces of a transparent substrate to form a reflection element; attaching the reflection element to the waveguide sheet; dispensing glue on one side of the reflection element facing away from the waveguide sheet to form an adhesion structure; adhering the optical engine or the spectacle frame to the adhesion structure.

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