Near-eye display device

Abstract

The application provides a near-eye display device. The near-eye display device comprises a first frame and a second frame corresponding to different human eyes; a waveguide assembly arranged in the first frame, the waveguide assembly comprising a waveguide substrate, an in-coupling grating and an out-coupling grating, the in-coupling grating and the out-coupling grating being arranged on the waveguide substrate; and a light-transmitting assembly arranged in the second frame, the light-transmitting assembly comprising a light-transmitting layer, the light-transmitting layer having a first structure region; the relative position, area size and shape of the first structure region on the light-transmitting layer are consistent with the relative position, area size and shape of the out-coupling grating on the waveguide substrate, and the light-transmitting rate and / or reflectivity of the first structure region are consistent with the light-transmitting rate and / or reflectivity of the out-coupling grating. The near-eye display device can improve the visual symmetry and comfort during monocular display.

Description

Technical Field

[0001] This invention relates to the field of display technology, and more particularly to a near-eye display device. Background Technology

[0002] In near-eye display devices, image light enters the human eye through three stages—coupled in, conducted, and coupled out—within the waveguide component, thus realizing the display of virtual images. Simultaneously, real light enters the human eye through the waveguide component, thereby ultimately achieving the superposition display of virtual images and real scenes.

[0003] In the design of the display solution, if the above-mentioned display optical path is only set in front of one of the user's eyes, that eye can see the superimposed image of virtual and real fusion, while the other eye is usually in front of ordinary lenses or optical components without display function, which can only perceive the real environment scene and does not include virtual images.

[0004] While this monocular configuration is relatively simple in structure and helps reduce power consumption and cost, the optical components on both sides of the monocular configuration have waveguide components and do not have waveguide components respectively. The difference in the transmission characteristics of real light between the two will lead to asymmetry of visual information received by the user's eyes, which can easily cause visual fatigue and may even have an adverse effect on the user's depth perception and color judgment ability. Summary of the Invention

[0005] This application provides a near-eye display device that can improve visual symmetry and comfort during monocular display.

[0006] This application provides a near-eye display device, including: The first and second frames correspond to different human eyes; The waveguide assembly disposed in the first mirror frame includes a waveguide substrate, a coupling grating, and a coupling grating, wherein the coupling grating and the coupling grating are respectively disposed on the waveguide substrate; A light-transmitting component disposed in the second frame, the light-transmitting component including a light-transmitting layer, the light-transmitting layer having a first structural region; The relative position, area, and shape of the first structural region on the light-transmitting layer are consistent with the relative position, area, and shape of the coupling grating on the waveguide substrate, and the transmittance and / or reflectance of the first structural region are consistent with the transmittance and / or reflectance of the coupling grating.

[0007] In some embodiments, a composite membrane is disposed on the first structural region.

[0008] In some embodiments, the composite film includes one or more first film layers and one or more second film layers, wherein the refractive index of the first film layer is greater than the refractive index of the second film layer, and the first film layer and the second film layer are alternately arranged.

[0009] In some embodiments, the material of the first film layer is one or a combination of titanium oxide, silicon and / or tantalum oxide.

[0010] In some embodiments, the thickness of the first film layer is 30 to 100 nm.

[0011] In some embodiments, the material of the second film layer is one or a combination of several of magnesium fluoride, silicon dioxide, silicon nitride, aluminum oxide and / or hafnium oxide.

[0012] In some embodiments, the thickness of the second film layer is 50 to 200 nm.

[0013] In some embodiments, a first microstructure is disposed on the first structural region, the first microstructure being a nanopillar arranged in a two-dimensional array, the cross-section of the nanopillar being circular or polygonal.

[0014] In some embodiments, the period of the nanopillars is 200 nm to 600 nm.

[0015] In some embodiments, the height of the nanopillars is 200 nm to 600 nm.

[0016] In some embodiments, the aspect ratio of the plurality of nanopillars is less than or equal to 10:1.

[0017] In some embodiments, a second microstructure is provided on the first structural region, the second microstructure being a diffractive optical element or a moth-eye structure.

[0018] In some embodiments, a third microstructure is provided on the first structural region, and the third microstructure is the same as the microstructure of the coupling grating.

[0019] In some embodiments, the transmittance and / or reflectance of the light-transmitting layer are consistent with the transmittance and / or reflectance of the waveguide substrate.

[0020] In some embodiments, the area and shape of the light-transmitting layer are consistent with the area and shape of the waveguide substrate.

[0021] In some embodiments, the waveguide assembly further includes a folding grating disposed on the waveguide substrate and located on the optical propagation path between the input grating and the output grating.

[0022] In some embodiments, the light-transmitting layer further has a second structural region, the relative position, area size and shape of the second structural region on the light-transmitting layer being consistent with the relative position, area size and shape of the transition grating on the waveguide substrate, and the light transmittance and / or reflectance of the second structural region being consistent with the light transmittance and / or reflectance of the transition grating.

[0023] The near-eye display device provided in this application embodiment allows the eye corresponding to the first frame to receive virtual images and observe the real scene through the waveguide component when worn by the user; the eye corresponding to the second frame observes the real scene through the light-transmitting component. Because the transmittance and / or reflectance of the first structural region of the light-transmitting layer in the light-transmitting component is consistent with the transmittance and / or reflectance of the coupling grating, the difference in real light received by the user's two eyes is reduced. Therefore, this near-eye display device can effectively improve visual symmetry and comfort during monocular display, reduce the risk of visual fatigue, and minimize adverse effects on the user's depth perception and color judgment. Attached Figure Description

[0024] To more clearly illustrate the technical solutions in the embodiments of this application, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0025] Figure 1 This is a schematic diagram of a first structure of a near-eye display device provided in an embodiment of this application.

[0026] Figure 2 This is a schematic diagram of the structure of the composite membrane provided in an embodiment of this application.

[0027] Figure 3 This is a schematic diagram of the waveguide assembly provided in an embodiment of this application.

[0028] Figure 4 This is a schematic diagram of a second structure of the near-eye display device provided in an embodiment of this application. Detailed Implementation

[0029] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of this application, and not all of them. All other embodiments obtained by those skilled in the art based on the embodiments of this application without creative effort are within the scope of protection of this application.

[0030] This application provides a near-eye display device to improve visual symmetry and comfort during monocular display. The following is a detailed description in conjunction with the accompanying drawings.

[0031] Please see Figure 1 , Figure 1 This is a schematic diagram of a first structure of a near-eye display device provided in an embodiment of this application.

[0032] This application provides a near-eye display device 100, which is a display device capable of directly presenting virtual image information within the user's field of vision. Specifically, the near-eye display device 100 provided in this application can take the form of wearable devices such as augmented reality (AR) glasses, smart glasses, or head-mounted displays.

[0033] Taking augmented reality glasses as an example, their core working principle is to superimpose and blend the virtual image light emitted by the image source with the ambient light, so that users can see the virtual image information superimposed on their field of vision while observing the real world, thus realizing an augmented reality experience that combines virtual and reality.

[0034] Specifically, the near-eye display device 100 provided in this application embodiment includes: a first lens frame 10 and a second lens frame 20 corresponding to different human eyes, a waveguide component 30 disposed in the first lens frame 10, and a light-transmitting component 40 disposed in the second lens frame 20.

[0035] The near-eye display device 100 can achieve monocular display, meaning that the first frame 10 corresponding to one eye (e.g., the left or right eye) is equipped with an image display unit (image source) and a waveguide component 30 for displaying virtual image information, while the second frame 20 corresponding to the other eye only has a light-transmitting component 40 for viewing the external environment and does not have an image display unit, thus lacking the function of displaying virtual image information. Compared to the binocular display mode, this monocular display mode has advantages such as simpler structure, lower power consumption, and lower cost, making it suitable for applications with relatively simple display requirements, such as navigation prompts, message notifications, and translated text.

[0036] In this embodiment, the first frame 10 is the frame corresponding to the eye with the display function (e.g., the left eye), and the second frame 20 is the frame corresponding to the eye without the display function (e.g., the right eye). Of course, in other embodiments, the eye with the display function can also be the right eye, and correspondingly, the second frame 20 is the frame corresponding to the left eye. This application embodiment does not limit this.

[0037] The near-eye display device 100 also includes a waveguide assembly 30 disposed in the first lens frame 10. The waveguide assembly 30 includes a waveguide substrate 31, a coupling grating 32, and a coupling grating 33, with the coupling grating 32 and coupling grating 33 respectively disposed on the waveguide substrate 31. The waveguide substrate 31 is typically made of a high-refractive-index transparent optical material, such as glass or transparent resin, and its function is to provide a medium channel for the total internal reflection propagation of light. The waveguide substrate 31 has opposing first and second surfaces, namely an inner surface facing the human eye and an outer surface facing away from the human eye. Light propagates within the waveguide substrate 31 through total internal reflection between the first and second surfaces.

[0038] The coupling grating 32 is disposed in the coupling region of the waveguide substrate 31, typically located at the edge of the waveguide substrate 31 or near the temple. The coupling grating 32 is used to diffract and couple the image light emitted from the image source into the interior of the waveguide substrate 31, ensuring it meets the total internal reflection condition and propagates within the waveguide substrate 31. The coupling grating 32 can be a one-dimensional or two-dimensional grating, and its parameters such as grating period, duty cycle, and etching depth are designed according to the wavelength of the light source and the required coupling angle.

[0039] The coupling grating 33 is disposed in the coupling region of the waveguide substrate 31, typically located in the central region of the waveguide substrate 31 or at a position corresponding to the user's pupil. The coupling grating 33 is used to diffract and couple the light propagating to the coupling region out of the waveguide substrate 31, allowing it to enter the human eye to form virtual image information. The coupling grating 33 can also be a one-dimensional or two-dimensional grating, and its parameters such as grating period, duty cycle, and etching depth determine the angular distribution and efficiency of the coupled light.

[0040] The near-eye display device 100 also includes a light-transmitting component 40 disposed in the second lens frame 20.

[0041] The light-transmitting component 40 includes a light-transmitting layer 41, which has a first structural region 42. The light-transmitting layer 41 allows ambient light to pass through, enabling the user to observe the external environment through the second frame 20. The light-transmitting layer 41 can be made of a transparent optical material, such as glass or transparent resin.

[0042] The relative position, size, and shape of the first structural region 42 on the light-transmitting layer 41 are consistent with the relative position, size, and shape of the coupling grating 33 on the waveguide substrate 31. Specifically, the position of the first structural region 42 on the light-transmitting layer 41 is the same as the position of the coupling grating 33 on the waveguide substrate 31 relative to their respective frames. For example, if the coupling grating 33 is located in the lower central region of the waveguide substrate 31, then the first structural region 42 is also located in the lower central region of the light-transmitting layer 41. The size of the first structural region 42 is the same as the size of the coupling grating 33, and the shape of the first structural region 42 is the same as the shape of the coupling grating 33, such as a rectangle, a circle, or other geometric shapes.

[0043] The transmittance and / or reflectance of the first structural region 42 are consistent with those of the coupling grating 33. It should be noted that "consistent transmittance and / or reflectance" here refers to similar optical performance at least in the wavelength and angular dimensions: firstly, the curves of transmittance or reflectance changing with wavelength are essentially identical; secondly, the response trends of transmittance or reflectance changing with the incident angle are essentially the same. This consistency ensures that the modulation effects of the first structural region and the coupling grating 33 on ambient light are highly symmetrical and interchangeable under different usage conditions and ambient light, thereby avoiding visual inhomogeneity or diffraction efficiency fluctuations.

[0044] For ambient light, in the visible light band, such as the wavelength range of 380nm to 780nm, the absolute value of the difference between the average transmittance of the first structural region 42 and the coupling grating 33 does not exceed 5%, preferably not more than 3%; or, the absolute value of the difference between the average reflectance of the first structural region 42 and the coupling grating 33 does not exceed 5%, preferably not more than 3%.

[0045] Meanwhile, at any single wavelength within the visible light band, the absolute value of the difference in transmittance between the first structural region 42 and the coupling grating 33 does not exceed 10%, preferably not more than 5%; or, the absolute value of the difference in reflectance between the first structural region 42 and the coupling grating 33 at any single wavelength does not exceed 10%, preferably not more than 5%.

[0046] For ambient light, at each incident angle within the incident angle range, the absolute value of the difference in transmittance or reflectance between the two at each wavelength in the visible light band does not exceed 10%, preferably not exceeding 5%.

[0047] In this embodiment, by setting a light-transmitting component 40 in the corresponding second frame 20 without display function, and setting a first structural region 42 on the light-transmitting component 40 that is identical in position, area, and shape to the coupling grating 33 and has the same light transmittance and / or reflectance, the transmission spectral characteristics received by the user's two eyes when observing the external environment are basically the same. Due to the consistent visual information received by both eyes, the brain does not need to continuously fuse and coordinate the two different visual signals, thereby effectively reducing the extra burden on the visual system, significantly reducing eye fatigue and dizziness caused by prolonged use, and greatly improving the wearing comfort of monocular waveguide glasses.

[0048] Meanwhile, due to the consistency in position, area and shape between the first structural region 42 and the coupling grating 33, the position and range of the optical non-uniform area perceived by the user in the field of vision are symmetrical, avoiding visual discomfort caused by the asymmetry of the optical characteristics of the two eyes, and further improving the naturalness and comfort of the visual experience.

[0049] In this embodiment, the transmittance and / or reflectance of the light-transmitting layer 41 are preferably consistent with the transmittance and / or reflectance of the waveguide substrate 31. Specifically, the difference between the average transmittance and / or reflectance of the light-transmitting layer 41 in the visible light band and the average transmittance and / or reflectance of the waveguide substrate 31 in the visible light band is preferably no more than 3%. Thus, in the region outside the first structural region 42, the transmittance and / or reflectance of the light-transmitting layer 41 are also preferably substantially consistent with the transmittance and / or reflectance of the waveguide substrate 31, further ensuring the consistency of binocular vision.

[0050] In this embodiment, the area and shape of the light-transmitting layer 41 are preferably the same as those of the waveguide substrate 31. In this way, the light-transmitting layer 41 and the waveguide substrate 31 are completely identical in appearance, which not only improves the aesthetics of the near-eye display device 100, but also makes the optical performance of the light-transmitting layer 41 and the waveguide substrate 31 more symmetrical in the edge field of view.

[0051] In some embodiments, please refer to Figure 2 , Figure 2 This is a schematic diagram of the composite film structure provided in an embodiment of this application. A composite film 43 is disposed on the first structural region 42. The composite film 43 is a film structure formed by sequentially depositing multiple thin films on the surface of the first structural region 42 of the light-transmitting layer 41. The function of the composite film 43 is to utilize the interference effect of the optical thin film to modulate the transmission spectrum characteristics of the first structural region 42, so that it matches the transmission spectrum characteristics of the coupling grating 33.

[0052] The composite film 43 includes one or more first film layers 431 and one or more second film layers 432. The refractive index of the first film layer 431 is greater than that of the second film layer 432, and the first film layers 431 and the second film layers 432 are alternately arranged. That is, the composite film 43 is a multilayer film structure formed by alternating stacks of high-refractive-index film layers and low-refractive-index film layers. For example, the composite film 43 can be an alternating structure of high-refractive-index layer / low-refractive-index layer / high-refractive-index layer / low-refractive-index layer...

[0053] When light passes through this multilayer film structure with alternating high and low refractive indices, it undergoes multiple reflections and transmissions at the interfaces of each layer, resulting in interference between the reflected light from different interfaces. By rationally designing the thickness and refractive index of each layer, the transmission of light within a specific wavelength range can be enhanced or weakened due to constructive or destructive interference, thereby achieving precise control of the transmission spectrum.

[0054] The first film layer 431 is made of a high refractive index material, such as one or a combination of titanium oxide (TiO2), silicon (Si), and / or tantalum oxide (Ta2O5). These materials have a high refractive index in the visible light band; for example, TiO2 has a refractive index of approximately 2.4 to 2.6, making it suitable as a high refractive index film layer. The thickness of the first film layer 431 is 30 to 100 nm, preferably 40 to 80 nm, and more preferably 50 to 70 nm. The thickness of the first film layer 431 can be optimized according to the requirements of the target transmission spectrum curve.

[0055] The second film layer 432 is made of one or more of magnesium fluoride (MgF2), silicon dioxide (SiO2), silicon nitride (Si3N4), aluminum oxide (Al2O3), and / or hafnium oxide (HfO2). These materials have low refractive indices in the visible light band (e.g., the refractive index of SiO2 is about 1.45~1.46, and the refractive index of MgF2 is about 1.38), making them suitable as low refractive index films. The thickness of the second film layer 432 is 50 to 200 nm, preferably 80 to 160 nm, and more preferably 100 to 140 nm. The thickness of the second film layer 432 can also be optimized according to the requirements of the target transmission spectrum curve.

[0056] The total number of film layers in the composite membrane 43, i.e., the sum of the number of the first film layer 431 and the second film layer 432, can be determined according to actual needs. Generally speaking, the more film layers there are, the stronger the ability to control the transmission spectrum, but the more complex the manufacturing process and the higher the cost. In some preferred embodiments of this application, the total number of film layers in the composite membrane 43 is 4 to 20, more preferably 6 to 12.

[0057] The composite film 43 can be prepared using vacuum deposition processes, such as electron beam evaporation, sputtering, or ion-assisted deposition. These processes can precisely control the thickness and uniformity of each film layer, ensuring the optical performance of the composite film 43.

[0058] In this embodiment, by setting a composite film 43 on the first structural region 42, the optical interference effect generated by the alternating stacking of high and low refractive index films can be used to precisely control the transmission spectrum curve of the first structural region 42, making it match the transmission spectrum curve of the coupling grating 33. The composite film 43 has high design flexibility; by adjusting the material, thickness, and number of layers, the transmittance and / or reflectance in different wavelength ranges can be precisely adjusted, thereby adapting to the transmittance and / or reflectance characteristics of different types of coupling gratings 33. For example, for a coupling grating 33 with low transmittance and / or reflectance in the blue light band and high transmittance and / or reflectance in the red light band, the composite film 43 can be designed to correspondingly reduce the transmittance and / or reflectance in the blue light band and correspondingly increase the transmittance and / or reflectance in the red light band, thereby achieving matching of the two transmission spectrum curves.

[0059] In some embodiments, a first microstructure is disposed on the first structural region 42, which is a nanopillar arranged in a two-dimensional array. The nanopillar is a nanoscale columnar protrusion structure formed on the surface of the first structural region 42 of the light-transmitting layer 41. Multiple nanopillars are regularly arranged in a two-dimensional plane according to a certain period, forming a nanopillar array. The cross-section of the nanopillar is circular or polygonal, such as square or regular hexagonal. The cross-sectional shape of the nanopillar affects its modulation effect on the external light field, and can be specifically selected according to the requirements of the target transmission spectrum curve.

[0060] The period of the nanopillars, i.e. the distance between the centers of two adjacent nanopillars, is 200 nm to 600 nm, preferably 250 nm to 500 nm, and more preferably 300 nm to 450 nm. The period of the nanopillars determines the duty cycle and equivalent refractive index of the nanopillar array, thereby affecting the transmission spectral characteristics of the first structural region 42.

[0061] The height of the nanopillars is 200 nm to 600 nm, preferably 250 nm to 500 nm, and more preferably 300 nm to 450 nm. The height of the nanopillars affects their phase modulation depth to the optical field, and also affects the transmission spectral characteristics of the first structural region 42.

[0062] The aspect ratio of multiple nanopillars, i.e., the ratio of the height of the nanopillar to its cross-sectional feature dimension, is less than or equal to 10:1, preferably less than or equal to 8:1, and more preferably less than or equal to 5:1. An appropriate aspect ratio helps ensure the mechanical strength and manufacturing yield of the nanopillars, and avoids collapse or breakage during manufacturing or use.

[0063] The first microstructure (nanopillar array) operates based on the equivalent medium effect of subwavelength structures. When the period of the nanopillars is smaller than the wavelength of the incident light (i.e., a subwavelength structure), the nanopillar array no longer behaves as a discrete scatterer for the incident light, but rather as a homogeneous dielectric layer with an equivalent refractive index. This equivalent refractive index lies between the refractive index of the nanopillar material and the refractive index of the surrounding medium (usually air), and can be precisely controlled by adjusting the period, height, and cross-sectional dimensions of the nanopillars.

[0064] By rationally designing the period, height, cross-sectional shape, and size of the nanopillars, the way in which the equivalent refractive index of the first structural region 42 changes with wavelength can be matched with the way in which the equivalent refractive index of the coupling grating 33 changes with wavelength, thereby achieving consistency in their transmission spectrum curves. For example, the optical properties of the nanopillar array can be optimized using the finite-difference time-domain (FDTD) method or the strictly coupled-wave analysis (RCWA) method to determine the combination of geometric parameters of the first microstructure.

[0065] The first microstructure can be fabricated using micro-nano fabrication processes such as nanoimprint lithography, electron beam lithography, or laser interference lithography. Among these, nanoimprint lithography has the advantages of low cost and high efficiency, making it suitable for mass production.

[0066] In some embodiments, a second microstructure is provided on the first structural region 42, the second microstructure being a diffractive optical element (DOE) or a moth-eye structure.

[0067] A diffractive optical element is an optical element that uses surface microstructures to modulate the phase of incident light, thereby achieving specific optical functions such as beam splitting, shaping, and focusing. In this embodiment, the diffractive optical element on the first structural region 42 is designed to have specific transmission spectral characteristics, so that its transmission spectral curve matches the transmission spectral curve of the coupling grating 33. The surface microstructure of the diffractive optical element can be a periodic grating structure or a more complex aperiodic structure. Its design method is based on diffractive optics theory, and the target transmission spectrum is achieved by optimizing the morphology of the surface microstructure.

[0068] The moth-eye structure is a biomimetic antireflective micro / nanostructure. This array of nanoscale protrusions, smaller than the wavelength of visible light, forms a gradient refractive index transition layer, gradually transitioning from the refractive index of air (approximately 1) to the refractive index of the substrate material. This gradient refractive index transition layer effectively suppresses light reflection at the interface, thereby significantly improving transmittance and / or modulating reflectance. Compared to traditional single-layer or double-layer antireflective films, the moth-eye structure offers advantages such as broad spectral adaptability and high thermal stability.

[0069] In this embodiment, the moth-eye structure on the first structural region 42 is designed to have a specific equivalent refractive index distribution, so that its transmission spectrum curve matches the transmission spectrum curve of the coupling grating 33. By adjusting the height, period, and shape of the nanoprotrusions in the moth-eye structure, such as cylindrical or conical, precise control of transmittance and / or reflectance in different wavelength ranges can be achieved.

[0070] The second microstructure can also be fabricated using micro-nano fabrication processes such as nanoimprint lithography, electron beam lithography, or laser interference lithography.

[0071] In some embodiments, a third microstructure is provided on the first structural region 42, and the third microstructure is the same as the microstructure of the coupling grating 33.

[0072] Specifically, the third microstructure is a microstructure formed on the surface of the first structural region 42 of the light-transmitting layer 41, and its parameters such as grating period, duty cycle, etching depth, and grating direction are the same as the corresponding parameters of the coupled grating 33.

[0073] The advantage of this embodiment is that, since the microstructure of the first structural region 42 is geometrically identical to that of the coupling grating 33, according to optical diffraction theory, their transmission spectrum responses to incident light are also essentially the same. Therefore, without complex optical design and simulation optimization, the transmittance and / or reflectance of the first structural region 42 can be directly guaranteed to be consistent with the transmittance and / or reflectance of the coupling grating 33.

[0074] Furthermore, this approach also offers significant advantages in manufacturing processes. Since the third microstructure is identical to the microstructure of the coupling grating 33, both can be fabricated using the same grating master stamp via nanoimprinting or replication. In other words, while manufacturing the coupling grating 33, the same microstructure can be simultaneously replicated on the first structural region 42 of the light-transmitting layer 41, eliminating the need for additional design and fabrication of a new master stamp, thereby significantly reducing manufacturing costs and process complexity.

[0075] It should be noted that although the third microstructure and the coupling grating 33 are geometrically identical, their functions are different. The function of the coupling grating 33 is to diffract and couple the light propagating within the waveguide substrate 31 to the human eye, therefore it needs to meet specific diffraction efficiency and diffraction angle requirements; while the function of the third microstructure is to regulate the transmission spectrum characteristics of the light-transmitting layer 41 to make it consistent with the transmittance and / or reflectance of the coupling grating 33, and it does not need to perform the function of coupling light itself.

[0076] In some embodiments, the transmittance and / or reflectance of the light-transmitting layer 41 are consistent with the transmittance and / or reflectance of the waveguide substrate 31. Specifically, both the light-transmitting layer 41 and the waveguide substrate 31 are made of the same high-refractive-index optical glass or transparent resin material, and both have the same thickness.

[0077] In some embodiments, the area and shape of the light-transmitting layer 41 are the same as those of the waveguide substrate 31. That is, the light-transmitting layer 41 is identical in appearance to the waveguide substrate 31.

[0078] In this embodiment, the first structural region 42 is provided only at the corresponding position on the light-transmitting layer 41. The first structural region 42 can be implemented in any of the above embodiments, that is, the first structural region 42 can be provided with a composite film 43, a first microstructure, a second microstructure or a third microstructure, or the transmittance and / or reflectance consistent with the coupling grating 33 can be achieved directly by treating the material or surface of the light-transmitting layer 41.

[0079] More preferably, the light-transmitting layer 41 can even directly adopt the same waveguide structure substrate as the waveguide substrate 31, that is, the light-transmitting layer 41 itself is also an optical waveguide substrate, and the grating structure at the corresponding position on the waveguide substrate 31 corresponding to the coupling grating 33 is directly utilized in the first structural region 42. In other words, the light-transmitting layer 41 retains a grating region with the same structure as the coupling grating 33 at the corresponding position, and this grating region constitutes the first structural region 42.

[0080] The advantages of this approach are as follows: First, the light-transmitting layer 41 and the waveguide substrate 31 are completely identical in material, thickness, and appearance, exhibiting symmetry and consistency, further enhancing the comfort of binocular vision. Second, the grating in the first structural region 42 can be fabricated using the same grating master template as the coupling grating 33, eliminating the need for additional mold making. Third, the light-transmitting layer 41 can utilize the same supply chain and manufacturing process as the waveguide component 30, which helps reduce the variety of materials and manufacturing costs.

[0081] In some embodiments, the method for matching the transmittance and / or reflectance of the coupling grating 33 and the first structural region 42 in the above embodiments is also involved.

[0082] As mentioned earlier, the transmittance and / or reflectance of the first structural region 42 need to be consistent with the transmittance and / or reflectance of the coupling grating 33. This can be achieved in the following ways.

[0083] First, the target spectral reference for the coupling grating 33 is obtained. This target spectral reference can be obtained in any of the following ways.

[0084] Method 1: Theoretical calculation. Based on the structural parameters of the coupled grating 33, including but not limited to grating period, duty cycle, etching depth, sidewall tilt angle and material refractive index dispersion characteristics, the theoretical transmission / reflection spectrum curve in the visible light band is calculated using numerical simulation methods such as coupled-wave analysis (RCWA) or finite-difference time-domain method (FDTD).

[0085] Method 2: Experimental Measurement. Using a spectrophotometer or angle-resolved spectrometer, the actual transmission / reflection spectrum curves of the prepared coupling grating 33 sample are obtained through spectral measurements.

[0086] If both methods are used simultaneously, and the deviation between the theoretical value and the measured value is within an acceptable range, the measured value shall be given priority as the reference for subsequent design.

[0087] Secondly, after obtaining the spectral curve of the coupling grating 33, it is used as the design target to formulate the first structural region 42. If the first structural region 42 adopts a composite film 43, the material, thickness and number of layers of each film layer are designed according to the target curve; if the first structural region 42 adopts a first microstructure, the period, height and cross-sectional shape and size of the nanopillars are designed according to the target curve.

[0088] Then, the transmission / reflection spectrum of the first structural region 42 is simulated and calculated using simulation software. The obtained simulation curve is compared with the target curve of the coupling grating 33, and the design parameters are repeatedly adjusted until the simulation level meets the matching standard. This standard is as described above: the difference in average transmittance and / or reflectance between the two in the visible light band does not exceed 5%, preferably 3%; the difference at each wavelength does not exceed 10%, preferably 5%; and within the incident angle range of 0° to 50°, the difference at each wavelength at each angle also does not exceed 10%, preferably 5%.

[0089] Finally, after successful simulation optimization, the coupling grating 33 and the light-transmitting component 40 were fabricated according to the design parameters. In the final verification stage, the same spectrophotometer was used under identical environmental conditions and incident angles to measure the actual fabricated coupling grating 33 and the first structural region 42, obtaining their measured spectral curves. The measured curve of the first structural region 42 was then directly compared with the measured curve of the coupling grating 33. Only when both measured curves simultaneously meet the aforementioned matching criteria can it be considered that optical matching has been achieved in the actual product.

[0090] If the cross-comparison fails, the process parameters or simulation model of the first structural region 42 are corrected according to the deviation trend of the two measured curves, and iterative optimization and preparation verification are carried out again until the final cross-comparison is passed.

[0091] In some embodiments, a method for assembling a near-eye display device 100 is also provided. Specifically, it includes the following steps.

[0092] First, a first frame 10 and a second frame 20 are provided. The first frame 10 and the second frame 20 can be manufactured by injection molding or metal processing, and the two can be connected by hinges or an integral bridge.

[0093] Then, the waveguide assembly 30 is installed in the first lens frame 10. The waveguide assembly 30 includes a waveguide substrate 31, a coupling grating 32, and an output grating 33. The waveguide assembly 30 can be fixed in the first lens frame 10 by adhesive bonding, snap-fitting, or mechanical fastening. The image source can be located in the temple area or edge of the first lens frame 10, and the image light formed therein is emitted towards the coupling grating 32.

[0094] Next, the light-transmitting component 40 is installed in the second mirror frame 20. The light-transmitting component 40 includes a light-transmitting layer 41 and a first structural region 42. The light-transmitting component 40 can also be fixed in the second mirror frame 20 by adhesive, snap-fit, or mechanical fastening. During installation, it must be ensured that the position of the first structural region 42 on the light-transmitting layer 41 corresponds to the position of the coupling grating 33 on the waveguide substrate 31.

[0095] Finally, optical testing is performed on the assembled near-eye display device 100 to verify whether the transmission spectral characteristics of the light-transmitting layer 41 and the waveguide substrate 31 are consistent, and whether the display function is normal.

[0096] It should be noted that the technical features in the above embodiments can be combined with each other without contradiction. For example, a composite film 43 and a first microstructure (nanopillar array) can be simultaneously disposed on the first structural region 42 to further improve the flexibility and precision of transmission spectrum modulation. As another example, the light-transmitting layer 41 can adopt the same material and structure as the waveguide substrate 31, while a third microstructure identical to the coupling grating 33 is disposed on the first structural region 42.

[0097] In some embodiments, please continue reading Figure 1 This application embodiment also provides a specific structure of the waveguide component 30 in a near-eye display device 100.

[0098] In this embodiment, the waveguide substrate 31 of the waveguide assembly 30 is made of a high-refractive-index optical glass material. The waveguide substrate 31 has a first surface and a second surface facing each other, wherein the first surface is the inner surface facing the human eye, and the second surface is the outer surface facing away from the human eye.

[0099] The coupling grating 32 is disposed on the second surface of the waveguide substrate 31, located in the edge region of the waveguide substrate 31. The coupling grating 32 is a one-dimensional grating. The material of the coupling grating 32 can be the same as that of the waveguide substrate 31, and it is formed by etching the surface of the waveguide substrate 31.

[0100] The output grating 33 is disposed on the second surface of the waveguide substrate 31, located in the central region of the waveguide substrate 31, corresponding to the position of the user's pupil. The output grating 33 is also a one-dimensional grating. The grating direction of the output grating 33 and the grating direction of the input grating 32 are determined according to the optical path design.

[0101] When the waveguide assembly 30 is operating, image light emitted from the image source is incident on the coupling grating 32 at a specific angle. After being diffracted by the coupling grating 32, the light enters the waveguide substrate 31, satisfies the total internal reflection condition, and propagates within the waveguide substrate 31. When the light propagates to the region of the coupling grating 33, it is diffracted by the coupling grating 33 and then coupled out from the first surface of the waveguide substrate 31, entering the human eye to form virtual image information.

[0102] In this embodiment, the transmission spectrum curve of the coupling grating 33 is affected by factors such as its grating period, duty cycle, etching depth, and material refractive index. By providing a microstructure or film layer on the first structural region 42 of the light-transmitting component 40 that matches the transmission spectrum of the coupling grating 33, the visual perception when observing the external environment with both eyes can be kept consistent.

[0103] Please see Figure 3 , Figure 3 This is a schematic diagram of the waveguide assembly provided in an embodiment of this application. The waveguide assembly 30 also includes a deflection grating 34, which is disposed on the waveguide substrate 31 and located on the optical propagation path between the coupling-in grating 32 and the coupling-out grating 33. The deflection grating 34 is used to deflect and expand the pupil of light rays diffracted from the coupling-in grating 32 into the waveguide substrate 31 and propagating within the waveguide substrate 31 by total internal reflection, thereby achieving two-dimensional pupil expansion and increasing the range of eye movement.

[0104] The transition grating 34 is also a one-dimensional grating. The grating direction of the transition grating 34 intersects the grating direction of the coupling grating 32 at a preset angle, which is determined according to the optical path design requirements of the two-dimensional pupil expansion. The transition grating 34 is made of the same material as the waveguide substrate 31, and is formed by etching the surface of the waveguide substrate 31. It is also fabricated synchronously in the same processing step as the coupling grating 32 and the coupling grating 33 to ensure the relative positional accuracy and grating consistency among the three.

[0105] Please see Figure 4 , Figure 4This is a schematic diagram of a second structure of the near-eye display device provided in an embodiment of this application. Further, the light-transmitting layer 41 also has a second structural region 44. The relative position, area, and shape of the second structural region 44 on the light-transmitting layer 41 are consistent with the relative position, area, and shape of the transition grating 34 on the waveguide substrate 31. The light transmittance and / or reflectance of the second structural region 44 are consistent with the light transmittance and / or reflectance of the transition grating 34.

[0106] It should be noted that the phrase "consistent transmittance and / or reflectance" here refers to the optical performance being nearly identical at least in the wavelength and angular dimensions: firstly, the curves of transmittance or reflectance changing with wavelength essentially overlap; secondly, the response trends of transmittance or reflectance changing with the incident angle are essentially the same. This consistency ensures that the modulation effects of the second structural region 44 and the deflection grating 34 on ambient light are highly symmetrical and interchangeable under different usage conditions and ambient light, thereby avoiding visual inhomogeneity or diffraction efficiency fluctuations.

[0107] For ambient light, in the visible light band, such as the wavelength range of 380nm to 780nm, the absolute value of the difference between the average transmittance of the second structure region 44 and the transition grating 34 does not exceed 5%, preferably not more than 3%; or, the absolute value of the difference between the average reflectance of the second structure region 44 and the transition grating 34 does not exceed 5%, preferably not more than 3%.

[0108] Meanwhile, at any single wavelength within the visible light band, the absolute value of the difference in transmittance between the second structural region 44 and the transition grating 34 does not exceed 10%, preferably not more than 5%; or, the absolute value of the difference in reflectance between the second structural region 44 and the transition grating 34 at any single wavelength does not exceed 10%, preferably not more than 5%.

[0109] For ambient light, at each incident angle within the incident angle range, the absolute value of the difference in transmittance or reflectance between the two at each wavelength in the visible light band does not exceed 10%, preferably not exceeding 5%.

[0110] This embodiment provides an application scenario for a near-eye display device 100.

[0111] The near-eye display device 100 provided in this application embodiment can be applied to wearable devices such as augmented reality glasses, smart glasses, and head-mounted displays. After wearing the device, the user can see virtual image information superimposed on the real scene through the eye with display function (corresponding to the first lens 10), while simultaneously seeing the real scene through the eye without display function (corresponding to the second lens 20). Since the transmission spectral characteristics of the light-transmitting layer 41 and the waveguide substrate 31 are basically the same, the user will not experience fatigue or discomfort due to the difference in binocular vision during prolonged use.

[0112] In particular, the near-eye display device 100 provided in this application embodiment is especially suitable for monocular AR glasses products, such as smart navigation glasses, translation glasses, and industrial auxiliary glasses. These products typically only need to display basic information such as navigation arrows, translated text, and device parameters in one eye, and have high requirements for binocular visual consistency. By adopting the technical solution provided in this application embodiment, the wearing comfort and user experience of such products can be significantly improved.

[0113] Furthermore, the technical solutions provided in this application are not only applicable to monocular waveguide glasses, but can also be extended to other types of monocular near-eye display devices 100, such as monocular head-mounted displays, monocular medical head mirrors, etc. As long as there is a problem of inconsistent light transmittance and / or reflectance between the eye with display function and the eye without display function in these devices, the technical solutions provided in this application can be used to improve the situation.

[0114] In the above embodiments, the descriptions of each embodiment have different focuses. For parts not described in detail in a certain embodiment, please refer to the relevant descriptions in other embodiments.

[0115] In the description of this application, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, features defined with "first" and "second" may explicitly or implicitly include one or more features.

[0116] The near-eye display device provided in the embodiments of this application has been described in detail above. Specific examples have been used to illustrate the principles and implementation methods of this application. The descriptions of the embodiments above are only for the purpose of helping to understand this application. Furthermore, those skilled in the art will recognize that, based on the ideas of this application, there will be changes in the specific implementation methods and application scope. Therefore, the content of this specification should not be construed as a limitation of this application.

Claims

1. A near-eye display device, characterized in that, include: First frame and second frame; The waveguide assembly disposed in the first mirror frame includes a waveguide substrate, a coupling grating, and a coupling grating, wherein the coupling grating and the coupling grating are respectively disposed on the waveguide substrate; A light-transmitting component disposed in the second frame, the light-transmitting component including a light-transmitting layer, the light-transmitting layer having a first structural region; The relative position, area, and shape of the first structural region on the light-transmitting layer are consistent with the relative position, area, and shape of the coupling grating on the waveguide substrate, and the transmittance and / or reflectance of the first structural region are consistent with the transmittance and / or reflectance of the coupling grating.

2. The near-eye display device according to claim 1, characterized in that, A composite membrane is disposed on the first structural region.

3. The near-eye display device according to claim 2, characterized in that, The composite film includes one or more first film layers and one or more second film layers, wherein the refractive index of the first film layer is greater than the refractive index of the second film layer, and the first film layer and the second film layer are alternately arranged.

4. The near-eye display device according to claim 3, characterized in that, The material of the first film layer is one or a combination of titanium oxide, silicon and / or tantalum oxide.

5. The near-eye display device according to claim 3, characterized in that, The thickness of the first film layer is 30 to 100 nm.

6. The near-eye display device according to claim 3, characterized in that, The material of the second film layer is one or a combination of several of magnesium fluoride, silicon dioxide, silicon nitride, aluminum oxide and / or hafnium oxide.

7. The near-eye display device according to claim 3, characterized in that, The thickness of the second film layer is 50 to 200 nm.

8. The near-eye display device according to claim 1, characterized in that, The first structural region is provided with a first microstructure, which is a nanopillar arranged in a two-dimensional array, and the cross-section of the nanopillar is circular or polygonal.

9. The near-eye display device according to claim 8, characterized in that, The period of the nanopillars is 200 nm to 600 nm.

10. The near-eye display device according to claim 8, characterized in that, The height of the nanopillars is between 200 nm and 600 nm.

11. The near-eye display device according to claim 8, characterized in that, The aspect ratio of the plurality of nanopillars is less than or equal to 10:

1.

12. The near-eye display device according to claim 1, characterized in that, A second microstructure is provided on the first structural region, and the second microstructure is a diffractive optical element or a moth-eye structure.

13. The near-eye display device according to claim 1, characterized in that, A third microstructure is provided on the first structural region, and the third microstructure is the same as the microstructure of the coupling grating.

14. The near-eye display device according to any one of claims 1 to 13, characterized in that, The transmittance and / or reflectance of the light-transmitting layer are consistent with the transmittance and / or reflectance of the waveguide substrate.

15. The near-eye display device according to any one of claims 1 to 13, characterized in that, The area and shape of the light-transmitting layer are consistent with the area and shape of the waveguide substrate.

16. The near-eye display device according to any one of claims 1 to 13, characterized in that, The waveguide assembly further includes a bend grating, which is disposed on the waveguide substrate and located on the optical propagation path between the input grating and the output grating.

17. The near-eye display device according to claim 16, characterized in that, The light-transmitting layer also has a second structural region. The relative position, area, and shape of the second structural region on the light-transmitting layer are consistent with the relative position, area, and shape of the folding grating on the waveguide substrate. The light transmittance and / or reflectance of the second structural region are consistent with the light transmittance and / or reflectance of the folding grating.

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