Optical waveguide device and AR glasses

Abstract

The invention provides an optical waveguide device and AR glasses, and relates to the technical field of augmented reality, the optical waveguide device comprises an optical machine, a first optical waveguide and a second optical waveguide, the first optical waveguide is provided with a first input area and a first output area, and the second optical waveguide is provided with a second input area and a second output area; the ray machine is arranged corresponding to the first input area, and the second input area is arranged corresponding to the first output area; the first input area and the first output area are respectively provided with gratings, and the second output area is provided with a spectroscope array; light emitted by the ray machine is coupled into the first optical waveguide through the first input area, is coupled into the second input area of the second optical waveguide through the first output area after being propagated in the first optical waveguide, and is coupled out through the second output area after being propagated through the second optical waveguide to form an image. The phenomenon of outward light leakage is effectively reduced or even eliminated, and user privacy leakage is avoided.

Description

Technical Field

[0001] The present application relates to the field of augmented reality technology, and in particular to an optical waveguide device and AR glasses. Background Art

[0002] In augmented reality (AR) display technology, diffraction waveguides have become the mainstream optical solution due to their lightness, thinness and high efficiency. The working principle of diffraction waveguides is to use grating diffraction to achieve the transmission and regulation of optical signals. The grating couples the light from the display source into the waveguide through the design of periodic structure, and transmits it in the waveguide through mechanisms such as total internal reflection, and finally couples out the image information and transmits it to the user's eyes, thereby realizing the display of virtual images.

[0003] However, due to the characteristics of grating diffraction, the diffraction process includes both reflective diffraction (light is reflected back to the incident side) and transmissive diffraction (light is transmitted to the other side). In practical applications, this characteristic causes some light to leak out of the optical waveguide from the other side when it is coupled out of the optical waveguide, resulting in light leakage. These light leaks not only affect the display effect, but may also expose the content that the user is watching, bringing the risk of privacy leakage. Therefore, effectively reducing or eliminating the light leakage problem in the diffraction optical waveguide has become an important technical problem that needs to be solved in AR display technology. Summary of the invention

[0004] The purpose of the embodiments of the present application is to provide an optical waveguide device and AR glasses that can effectively reduce or even eliminate the phenomenon of outward light leakage and avoid user privacy leakage.

[0005] In one aspect of an embodiment of the present application, an optical waveguide device is provided, including an optical machine, a first optical waveguide, and a second optical waveguide, wherein a first input region and a first output region are provided on the first optical waveguide, and a second input region and a second output region are provided on the second optical waveguide; the optical machine is provided corresponding to the first input region, and the second input region is provided corresponding to the first output region; gratings are provided in the first input region and the first output region, respectively, and a spectroscope array is provided in the second output region;

[0006] The light emitted by the optical machine is coupled into the first optical waveguide through the first input area, coupled into the second input area of ​​the second optical waveguide through the first output area after propagating in the first optical waveguide, and coupled out through the second output area after propagating through the second optical waveguide to form an image.

[0007] Optionally, the beam splitter array includes a plurality of beam splitters, and each beam splitter has a different reflection and transmission ratio.

[0008] Optionally, along the propagation direction of the light, the reflection energy ratios of the plurality of beam splitters are arranged in an array with gradually increasing ratios.

[0009] Optionally, the second input area is a reflective surface.

[0010] Optionally, a high-reflection film is disposed on the second input area.

[0011] Optionally, the grating is a one-dimensional grating, and a propagation direction of the light in the first optical waveguide is perpendicular or parallel to a propagation direction of the light in the second optical waveguide.

[0012] Optionally, the grating on the first output region of the first optical waveguide is a two-dimensional grating or a one-dimensional grating in two different directions printed on both sides.

[0013] Optionally, a turning area is further provided on the first optical waveguide, and the turning area is located between the first input area and the first output area.

[0014] Optionally, a shielding structure is correspondingly arranged in the first output region of the first optical waveguide to prevent light leakage.

[0015] Another aspect of an embodiment of the present application provides an AR pair of glasses, including: the above-mentioned optical waveguide device.

[0016] The optical waveguide device and AR glasses provided in the embodiments of the present application are provided with gratings in the first input area and the first output area of ​​the first optical waveguide, respectively, so that the light of the optical machine is diffracted into the first optical waveguide through the first input area, and then diffracted into the second optical waveguide through the first output area, so as to couple the light into the optical system. In the second output area, a spectroscope array is provided, and reflection is used to couple out the light. The direction of the reflected light is single, so it is used as the final coupled output, and very little or even almost no light will be coupled out from the other side, which effectively reduces the intensity of light leakage. Through the combination of the diffraction input optical waveguide and the array output optical waveguide, the phenomenon of light leakage to the outside can be effectively reduced or even eliminated, and the user's privacy can be avoided. In addition, since the final output area is composed of the array output optical waveguide, the array output optical waveguide does not need to be diffracted, which can also eliminate the root cause of the rainbow pattern. Therefore, this architecture has no rainbow glare caused by the external light environment, and improves the display effect. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the drawings required for use in the embodiments of the present application will be briefly introduced below. It should be understood that the following drawings only show certain embodiments of the present application and therefore should not be regarded as limiting the scope. For ordinary technicians in this field, other related drawings can be obtained based on these drawings without paying creative work.

[0018] Figure 1 It is a schematic diagram of the prior art structure;

[0019] Figure 2 is one of the structural schematic diagrams of the optical waveguide device provided in this embodiment;

[0020] Figure 3 yes Figure 2 Side view of

[0021] Figure 4 This is the second structural schematic diagram of the optical waveguide device provided in this embodiment;

[0022] Figure 5 yes Figure 4 Side view of

[0023] Figure 6 This is the third structural schematic diagram of the optical waveguide device provided in this embodiment;

[0024] Figure 7 yes Figure 6 Side view of.

[0025] Icons: 10 - optical machine; 11 - first optical waveguide; 111 - first input region; 112 - first output region; 113 - turning region; 12 - second optical waveguide; 121 - second input region; 122 - second output region; 123 - spectrometer array. DETAILED DESCRIPTION

[0026] The technical solutions in the embodiments of the present application will be clearly and completely described below in conjunction with the drawings in the embodiments of the present application.

[0027] In the description of this application, it should be noted that the terms "inside", "outside", etc. indicate the orientation or positional relationship based on the orientation or positional relationship shown in the drawings, or the orientation or positional relationship in which the product of the application is usually placed when in use, which is only for the convenience of describing this application and simplifying the description, and does not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on this application. In addition, the terms "first", "second", etc. are only used to distinguish the description, and cannot be understood as indicating or implying relative importance.

[0028] It should also be noted that, unless otherwise clearly specified and limited, the terms "disposed" and "connected" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a direct connection, or an indirect connection through an intermediate medium, or it can be the internal communication of two elements. For ordinary technicians in this field, the specific meanings of the above terms in this application can be understood according to specific circumstances.

[0029] In a diffraction waveguide, due to the characteristics of grating diffraction, the diffraction process includes both reflective diffraction (light is reflected back to the incident side) and transmissive diffraction (light is transmitted to the other side). In practical applications, this characteristic causes part of the light to leak out of the waveguide from the other side when it is coupled out of the waveguide, forming a light leakage phenomenon.

[0030] like Figure 1 As shown, in the exit pupil grating area, part of the light is coupled into the human eye, and the other part of the light is coupled out from the opposite side, forming light leakage.

[0031] Moreover, the proportion of this light leakage is not low, and even some grating designs can have a very high light leakage ratio of 1:1, which means that the brightness of the image viewed by the outside world is basically the same as that viewed by the human eye. These light leaks not only affect the display effect, but may also expose the content that the user is watching, bringing the risk of privacy leakage.

[0032] To solve the above problems, refer to Figure 2 As shown, an embodiment of the present application provides an optical waveguide device, including a first optical waveguide 11, a second optical waveguide 12 and an optical engine 10, wherein the optical engine can be one of a DLP optical engine, a MicroLED optical engine, and an LCOS optical engine.

[0033] The first optical waveguide 11 is provided with a first input region 111 and a first output region 112 , and the second optical waveguide 12 is provided with a second input region 121 and a second output region 122 ;

[0034] The optical machine 10 is arranged corresponding to the first input area 111, and the second input area 121 is arranged corresponding to the first output area 112;

[0035] Gratings are respectively arranged in the first input region 111 and the first output region 112 , and the gratings can be formed by template imprinting or volume holographic exposure, and a beam splitter array 123 is arranged in the second output region 122 ;

[0036] The light emitted by the optical machine 10 is coupled into the first optical waveguide 11 through the first input area 111, and reaches the first output area 112 after multiple total reflections in the first optical waveguide 11, and is coupled out of the first optical waveguide 11 by the first output area 112, and then propagates into the second optical waveguide 12, and propagates inside the second optical waveguide 12 after being reflected by the second input area 121, and then reaches the second output area 122, and is coupled out of the second optical waveguide 12 through the second output area 122 to form an image.

[0037] Due to the diffraction characteristics of the grating, gratings are respectively set in the first input area 111 and the first output area 112 of the first optical waveguide 11, and light path propagation is performed based on the principle of grating diffraction, so that the light of the optical machine 10 is diffracted into the first optical waveguide 11 through the first input area 111, and then diffracted into the second optical waveguide 12 through the first output area 112, so as to couple the light into the optical system.

[0038] In the second output region 122, a beam splitter array 123 is provided to utilize reflection to couple out light. The direction of the reflected light is single, so it is used as the final coupled output. Very little (multiple film layers are provided on the beam splitter, and multiple reflections may occur between the film layers, causing some light to leak out) or even almost no light is coupled out from the other side, thereby effectively reducing the intensity of the leaked light.

[0039] Tests on some AR products that use arrayed optical waveguides alone show that the proportion of light leakage from the front side is less than 1%, which means that if the image brightness entering the user is 1000nit, the brightness of the light leakage from the front side is less than 10nit. This extremely low brightness is very difficult for the human eye to perceive. It can only be perceived in a dark enough environment and when the human eye is very close to the front side of the product. Therefore, it can be completely considered that the light leakage of the array output optical waveguide can be ignored. Therefore, using the array output optical waveguide as the structure on the output side of the human eye is the only choice to prevent light leakage.

[0040] However, the array output optical waveguide can only expand the light source in one dimension, which will cause the image coupled out by the array output optical waveguide alone to be too small. If the array output optical waveguide is to be used to expand the light source in multiple dimensions, a two-dimensional beam splitter array 123 is required; however, the beam splitter needs to be plated with multiple layers of different films, which makes its process very difficult and the yield is currently very low, and the yield of two-dimensional beam splitters is even lower and more difficult to achieve. However, the advantages and disadvantages of the diffraction input optical waveguide are exactly the opposite of those of the array output optical waveguide. The diffraction input optical waveguide is placed at the input end. Before the light source enters the array output optical waveguide, at least one light source expansion is achieved. The diffraction input optical waveguide propagates and expands the light source based on the grating. At present, the process of making gratings on optical waveguides is relatively mature and relatively easy to achieve.

[0041] Therefore, the present application uses the first optical waveguide 11 as the diffraction input optical waveguide and the second optical waveguide 12 as the array output optical waveguide. Through the combined architecture of the diffraction input optical waveguide and the array output optical waveguide, the phenomenon of light leakage to the outside can be effectively reduced or even eliminated to avoid leakage of user privacy. In addition, since the final output area is composed of the array output optical waveguide, the array output optical waveguide does not need to be diffracted, which can also eliminate the root cause of the rainbow pattern. Therefore, the architecture has no rainbow glare caused by the external light environment, which improves the display effect.

[0042] In addition to the above-mentioned function of light path propagation, the diffraction input optical waveguide can also realize the function of expanding the light source, thereby making the light spot larger when it subsequently enters the array output optical waveguide.

[0043] As the name implies, light source expansion means making the light source larger. When the optical waveguide has the light source expansion function, the volume of the optical machine 10 can be reduced. In AR devices, especially AR glasses, there are very high requirements for the volume of the device. If the volume of the optical machine 10 is too large, the volume of the device will increase, and the weight will also increase. The volume of the optical machine 10 is positively correlated with the size of the light source. Usually, AR devices have a minimum requirement for the size of the light spot. Therefore, if there is no light source expansion function, the volume of the optical machine 10 has to increase in order to output a large enough light spot. With the light source expansion function, the volume of the optical machine 10 can be reduced, and a smaller light spot can be output. The size of the light spot can then be expanded by the light source to meet the size requirements of the imaging light spot.

[0044] In addition, a turning region 113 may be selectively provided on the first optical waveguide 11 , through which a second dimension of light source expansion may be achieved. The turning region 113 is provided between the first input region 111 and the first output region 112 on the first optical waveguide 11 .

[0045] The light spot after the light source expansion is output from the first output area 112 and reaches the second input area 121 of the second optical waveguide 12. At the position corresponding to the first output area 112 of the first optical waveguide 11, since it does not participate in the final optical imaging output, a structural shielding can be set at the periphery, so that even if light leakage occurs at this position, it cannot be viewed by the outside world, thereby further improving the design of preventing light leakage.

[0046] The second input region 121 of the second optical waveguide 12 can be a reflective surface, for example, it can be coated with a high-reflective film, which reflects the light into the second optical waveguide 12 for propagation, and then reaches the second output region 122. The second output region 122 of the second optical waveguide 12 is provided with a beam splitter array 123, and the beam splitter array 123 includes a plurality of beam splitters, and a plurality of beam splitter arrays are provided. When the light propagating inside the second optical waveguide 12 passes through the beam splitter array 123, part of the light will be reflected out of the second optical waveguide 12 to form an image, and part of the light will pass through a beam splitter in the beam splitter array 123 to reach the next beam splitter, and then repeat the above process. This process is essentially a process of side output and side light source expansion, and the direction of light source expansion can be set to be different from the direction of the first optical waveguide 11, so that multi-dimensional light source expansion can be achieved.

[0047] It should be noted that the beam splitter is just a name, and does not mean that all beam splitters in the present application are half-reflective and half-transmissive. In fact, in order to ensure uniform brightness of the outcoupled image, the reflection and transmission ratios of each beam splitter in the beam splitter array 123 are different.

[0048] Preferably, as the light path propagates, the proportion of energy reflected by the beam splitters in the beam splitter array 123 along the light propagation direction becomes higher and higher, and the reflected energy ratios of the multiple beam splitters are arranged in a gradually increasing array, that is, the first mirror encountered by the light during propagation has the lowest proportion of energy reflected from the second optical waveguide 12, and the proportion of energy reflected from the second optical waveguide 12 by the beam splitters further in the propagation direction becomes higher, so that the uniformity of the coupled image can be ensured as much as possible.

[0049] The following is explained by different embodiments. In the first embodiment, the propagation direction of the light in the first optical waveguide 11 is perpendicular to the propagation direction of the light in the second optical waveguide 12. In this case, the grating is a one-dimensional grating. Alternatively, Figure 3 The configuration is such that the propagation direction of the light in the first optical waveguide 11 is parallel to the propagation direction of the light in the second optical waveguide 12. To facilitate the overall understanding of the structure and the propagation path of the light, as shown in FIG. Figure 4 , Figure 5 As shown, the light propagates in the first optical waveguide 11 along the x direction and propagates in the second optical waveguide 12 along the y direction, wherein the x direction is perpendicular to the y direction.

[0050] The light is coupled into the first input region 111 of the first optical waveguide 11, propagates along the x direction after multiple total reflections, and reaches the first output region 112 of the second optical waveguide 12. The light completes an expansion in the x direction in the first optical waveguide 11. The first output region 112 couples the light out to the second input region 121 of the second optical waveguide 12. The second input region 121 reflects the light along the y direction, and reaches the second output region 122 after multiple reflections. The second output region 122 is a beam splitter array 123. The light is reflected and coupled out of the second optical waveguide 12 to form an image, while continuing to propagate along the y direction, forming a light source expansion in the y direction, thereby completing the light source expansion in the x and y directions to form a virtual image.

[0051] Through the above settings, light leakage can be effectively prevented and light can be prevented from being emitted from the other side of the user, thereby protecting the user's privacy and improving the privacy of the device.

[0052] In Example 2, referring to Figure 3 As shown, Figure 2 Can be seen as Figure 3side view; the grating on the first output region 112 of the first optical waveguide 11 of implementation II is set to a two-dimensional grating or a one-dimensional grating in two different directions printed on both sides, both of which can achieve the effect of two-dimensional expansion of the light source. At this time, the light source expansion in the x and y directions can be completed simultaneously through the first output region 112.

[0053] It can be seen that the main difference between the second embodiment and the first embodiment is that the first output area 112 of the second embodiment adopts a two-dimensional extended light source mode, so that the light source completes the expansion in the x and y directions at the same time when it is in the first optical waveguide 11, and there is no need to consider the expansion direction on the array output optical waveguide; at the same time, the placement direction of the first optical waveguide 11 is also more free, and can be as follows Figure 3 The vertical placement shown in the figure can also be horizontally placed as in the first embodiment, or tilted at any other angle, as long as the first output area 112 is always arranged corresponding to the second input area 121. This facilitates the subsequent overall structure design. The optical imaging process of the second embodiment is consistent with that of the first embodiment, and will not be repeated here.

[0054] In the second embodiment, while keeping the core structure of the diffraction input optical waveguide + array output optical waveguide unchanged, the internal design of the diffraction input optical waveguide is changed to achieve the effect of a two-dimensional extended light source in the first output area 112, so that the diffraction input optical waveguide can be placed more freely, which is convenient for the subsequent structural design of the whole machine.

[0055] Example 3 Reference Figure 6 , Figure 7 , Figure 6 The light path propagation on the first optical waveguide 11 is shown. A turning area 113 is also provided on the first optical waveguide 11. The turning area 113 is located between the first input area 111 and the first output area 112 for light expansion.

[0056] Therefore, the first optical waveguide 11 can also achieve two-dimensional pupil expansion through the turning area 113, and the turning area 113+the first output area 112 is equivalent to the first output area 112 of the second embodiment. The light source is coupled into the first optical waveguide 11 from the first input area 111, turns through the turning area 113 and reaches the first output area 112, then is coupled out of the first optical waveguide 11 by the first output area 112, reaches the second input area 121 on the second optical waveguide 12, reaches the second output area 122 after reflection and propagation through the second input area 121, and is coupled out of the second optical waveguide 12 after passing through the beam splitter array 123 in the second output area 122, thereby forming an image.

[0057] Compared with the first two embodiments, the third embodiment sets the turning area 113 in the first optical waveguide 11, which has a better effect than the second embodiment that sets the two-dimensional grating in the first output area 112 alone, because the two-dimensional grating involves gratings in two dimensions, the design is complex, and the efficiency is lower than that of the one-dimensional grating; therefore, the light path propagation in three areas on the first optical waveguide 11 can take into account both efficiency and design difficulty.

[0058] In summary, the present application adopts a double-layer hybrid waveguide combination technology of a diffraction input optical waveguide and an array output optical waveguide, wherein a first input area 111 and a first output area 112 are provided on the diffraction input waveguide; a second input area 121 and a second output area 122 are provided on the array output waveguide; the second input area 121 receives the extended light source output from the first output area 112, and then propagates to the second output area 122 to couple the output of the second optical waveguide 12 to form an image that can be viewed by the human eye.

[0059] The optical waveguide device of the present application can be applied to various architectures and scenarios of augmented reality (AR) display systems, aiming to solve the light leakage problem of traditional diffraction optical waveguides.

[0060] The following is its system architecture and typical application scenarios:

[0061] AR glasses: In the design of augmented reality glasses, the double-layer hybrid waveguide is used as the core component of the display optical module. The system architecture includes one or more optical machines 10, the light of which is first coupled and propagated through the diffraction input optical waveguide, and then the array output optical waveguide completes the final image output. Since the array output optical waveguide can effectively suppress light leakage, AR glasses can achieve high privacy and clear image display when worn by users, preventing the outside world from seeing the display content.

[0062] Head-up display (HUD) system: In automotive or aviation head-up displays, double-layer hybrid waveguides can be used to enhance the performance of the display system. The system projects navigation, speed, and auxiliary driving information into the driver's line of sight. After being processed by the double-layer waveguide, light leakage out of the window is avoided, ensuring the driver's privacy and the clarity of information. This architecture improves the contrast of the display and reduces external interference.

[0063] Medical AR display: During surgery or other medical procedures, doctors can use AR devices containing double-layer hybrid waveguides to view patient data or images in real time. The reflective properties of the double-layer waveguide can prevent light leakage from the operating room, ensure the privacy of the displayed content, and provide high-resolution images to help doctors operate more accurately.

[0064] Industrial AR auxiliary system: In industrial maintenance and repair scenarios, wearing an AR display device containing a double-layer hybrid waveguide can present real-time information such as equipment status and operation steps. The double-layer waveguide can reduce interference from other light sources in the industrial environment, such as eliminating the rainbow pattern phenomenon, making the display content easier to read and improving the operating efficiency and safety of workers.

[0065] Through these application scenarios, the double-layer hybrid waveguide not only improves the image quality and privacy of the display system, but also expands its diverse applications in the AR field, providing users with a better augmented reality experience.

[0066] The present application also discloses an AR glasses, including an optical waveguide device as described above. The AR glasses include the same structure and beneficial effects as the optical waveguide device in the aforementioned embodiment. The structure and beneficial effects of the optical waveguide device have been described in detail in the aforementioned embodiment and will not be repeated here.

[0067] The above description is only an embodiment of the present application and is not intended to limit the protection scope of the present application. For those skilled in the art, the present application may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present application shall be included in the protection scope of the present application.

Claims

1. An optical waveguide device, characterized in that: include: An optical machine, a first optical waveguide and a second optical waveguide, wherein the first optical waveguide is provided with a first input region and a first output region, and the second optical waveguide is provided with a second input region and a second output region; the optical machine is provided corresponding to the first input region, and the second input region is provided corresponding to the first output region; gratings are provided in the first input region and the first output region, respectively, and a spectroscope array is provided in the second output region; The light emitted by the optical machine is coupled into the first optical waveguide through the first input area, coupled into the second input area of ​​the second optical waveguide through the first output area after propagating in the first optical waveguide, and coupled out through the second output area after propagating through the second optical waveguide to form an image.

2. The optical waveguide device according to claim 1, characterized in that The beam splitter array includes a plurality of beam splitters, and each of the beam splitters has a different reflection and transmission ratio.

3. The optical waveguide device according to claim 2, characterized in that Along the propagation direction of the light, the reflection energy ratios of the plurality of beam splitters are arranged in an array with gradually increasing ratios.

4. The optical waveguide device according to claim 1, wherein: The second input area is a reflective surface.

5. The optical waveguide device according to claim 4, characterized in that A high reflection film is arranged on the second input area.

6. The optical waveguide device according to any one of claims 1 to 5, characterized in that: The grating is a one-dimensional grating, and the propagation direction of the light in the first optical waveguide is perpendicular or parallel to the propagation direction of the light in the second optical waveguide.

7. The optical waveguide device according to any one of claims 1 to 5, characterized in that: The grating on the first output region of the first optical waveguide is a two-dimensional grating or a one-dimensional grating in two different directions printed on both sides.

8. The optical waveguide device according to any one of claims 1 to 5, characterized in that: The first optical waveguide is also provided with a turning area, and the turning area is located between the first input area and the first output area.

9. The optical waveguide device according to claim 8, characterized in that A shielding structure is correspondingly arranged in the first output region of the first optical waveguide to prevent light leakage.

10. An AR glasses, characterized in that: An optical waveguide device comprising any one of claims 1 to 9.

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