Diffraction optical waveguide and near-to-eye display device

Abstract

The embodiment of the utility model discloses a diffraction optical waveguide and a near-to-eye display device. The diffractive optical waveguide comprises at least one waveguide substrate, and the refractive index of the waveguide substrate is 1.4-2.2; the at least one coupling-in grating area is located on the waveguide substrate, the coupling-in grating area comprises a coupling-in grating, and the period of the coupling-in grating ranges from 150 nm to 700 nm; image light enters the coupling-in grating area of the waveguide substrate, and part of image light corresponding to the field angle is diffracted into the waveguide substrate through the coupling-in grating and is coupled out to human eyes after being totally reflected and transmitted in the waveguide substrate. According to the diffraction optical waveguide provided by the embodiment of the utility model, through setting a proper coupling grating period, the diffraction optical waveguide realizes propagation of partial field angle light, and at least two partial field angles are superposed to form a complete field angle.

Description

Technical Field

[0001] The utility model relates to the technical field of near-eye display, and in particular to a diffraction light waveguide and a near-eye display device. Background Art

[0002] In the field of near-eye displays, such as virtual reality (VR) or augmented reality (AR) devices, optical waveguides are often used as core components. Incident light can be transmitted within the waveguide based on the principle of total internal reflection. A diffraction grating is provided on the waveguide to couple light into the waveguide or couple light out of the waveguide for display and imaging.

[0003] However, the existing technology has the problem of small field of view, which affects the display effect. Utility Model Content

[0004] The utility model provides a diffraction light waveguide and a near-eye display device. The diffraction light waveguide realizes the propagation of light with partial viewing angles by setting a suitable coupling grating period, and the superposition of at least two partial viewing angles forms a complete viewing angle.

[0005] According to one aspect of the present invention, there is provided a diffractive optical waveguide, comprising:

[0006] At least one waveguide substrate, wherein the refractive index of the waveguide substrate is in the range of 1.4 to 2.2;

[0007] At least one coupling-in grating region located on the waveguide substrate, the coupling-in grating region comprising a coupling-in grating, and a period of the coupling-in grating is between 150 nm and 700 nm;

[0008] The image light is incident on the coupling grating area of ​​the waveguide substrate, and the image light corresponding to a part of the field angle is diffracted into the waveguide substrate through the coupling grating, and is coupled out to the human eye after total reflection transmission in the waveguide substrate.

[0009] Optionally, the diffraction optical waveguide includes a waveguide substrate, and the period of the coupling-in grating satisfies the following formula:

[0010]

[0011] Where D represents the period of the coupling grating, FOV represents the field of view, λ represents the wavelength of the incident light, and n a represents the refractive index of air, n g represents the refractive index of the waveguide substrate.

[0012] Optionally, the diffraction optical waveguide includes a waveguide substrate, and the period of the coupling-in grating satisfies the following formula:

[0013]

[0014] Where D represents the period of the coupling grating, FOV represents the field of view, λ represents the wavelength of the incident light, and n a represents the refractive index of air, n g represents the refractive index of the waveguide substrate.

[0015] Optionally, the diffraction optical waveguide comprises at least two stacked waveguide substrates, and the periods of the coupling-in gratings in at least two of the waveguide substrates are different;

[0016] At least two of the waveguide substrates include a first waveguide substrate and a second waveguide substrate, the first waveguide substrate transmits light of a first field of view angle, the second waveguide substrate transmits light of a second field of view angle, the light of the first field of view angle and the light of the second field of view angle are superimposed to form light of a superimposed field of view angle, which is coupled out to the human eye.

[0017] Optionally, the field angle of each waveguide substrate transmission satisfies the following formula:

[0018]

[0019] Where FOV represents the field of view, λ represents the wavelength of light transmitted by the diffraction waveguide, and n a represents the refractive index of air, n g represents the refractive index of the waveguide substrate, Fh represents the decomposition height of the field angle in the vector domain, Fw represents the maximum decomposition width of the field angle in the vector domain, and n F Indicates the number of decompositions of the full field of view, n F is an integer and is obtained by rounding up the result of the formula, n F / 2 Indicates the number of decompositions of the half-field angle, n F / 2 It is an integer obtained by rounding up the result of the formula.

[0020] Optionally, the coupling-in grating includes a one-dimensional grating or a two-dimensional grating.

[0021] According to another aspect of the present invention, a near-eye display device is provided, comprising a binocular glasses module, the binocular glasses module comprising a frame, an optical engine, and the diffraction light waveguide as described above, the diffraction light waveguide comprising a central coupling-in grating region and a first coupling-out grating region and a second coupling-out grating region located on both sides of the coupling-in grating region, the image light emitted by the optical engine is incident on the coupling-in grating region, the light of a first part of the field of view angle is transmitted through the diffraction light waveguide to the first coupling-out grating region and coupled out to the user's left eye, and the light of a second part of the field of view angle is transmitted through the diffraction light waveguide to the second coupling-out grating region and coupled out to the user's right eye.

[0022] According to another aspect of the present invention, a near-eye display device is provided, comprising a binocular glasses module, wherein the binocular glasses module comprises a frame, an optical machine, and two diffraction light waveguides as described above, wherein the two diffraction light waveguides respectively form a left eye lens and a right eye lens of the binocular glasses module.

[0023] Optionally, the period of the coupling grating in the diffraction optical waveguide satisfies

[0024] The left eye lens transmits the image of the left half field of view angle to the user's left eye, and the right eye lens transmits the image of the right half field of view angle to the user's right eye.

[0025] Optionally, the period of the coupling grating in the diffraction optical waveguide satisfies

[0026]

[0027] The left-eye lens transmits the image of the right half field of view angle to the user's left eye, and the right-eye lens transmits the image of the left half field of view angle to the user's right eye.

[0028] Optionally, the coupling grating periods of the left-eye lens and the right-eye lens are the same and are centered within the range of the calculation results.

[0029] According to another aspect of the present invention, a near-eye display device is provided, comprising a monocular glasses module, wherein the monocular glasses module comprises a frame, an optical machine, and the diffraction light waveguide as described above, wherein the waveguide substrates of different layers in the diffraction light waveguide transmit light of a partial field of view angle to synthesize a complete field of view angle.

[0030] According to another aspect of the present invention, a near-eye display device is provided, including a binocular glasses module, a binocular glasses module frame, an optical machine and two diffraction light waveguides as described above, the two diffraction light waveguides respectively forming a left eye lens and a right eye lens of the binocular glasses module, the waveguide substrates of different layers in the left eye lens transmit light of a part of the field of view angle, and the left eye lens is synthesized to achieve a field of view angle of half side, the waveguide substrates of different layers in the right eye lens transmit light of a part of the field of view angle, and the right eye lens is synthesized to achieve a field of view angle of the other half side, and the left eye lens and the right eye lens achieve a complete field of view angle after the image is combined.

[0031] The diffraction optical waveguide provided by the embodiment of the present invention includes at least one waveguide substrate and at least one coupling-in grating region located in the waveguide substrate. The refractive index of the waveguide substrate is in the range of 1.4 to 2.2. The coupling-in grating region includes a coupling-in grating. The period of the coupling-in grating is between 150 nm and 700 nm. Image light is incident on the coupling-in grating region of the waveguide substrate. Image light corresponding to a partial field of view angle is diffracted into the waveguide substrate through the coupling-in grating. After being totally reflected and transmitted in the waveguide substrate, it is coupled out to the human eye. The technical solution of the embodiment of the present utility model enables the diffraction optical waveguide to realize the propagation of light with a partial field of view angle by setting a suitable coupling-in grating period. The superposition of at least two partial field of view angles forms a complete field of view angle, thereby realizing the propagation of a large field of view angle under low refractive index. Since the refractive index of the waveguide substrate is positively correlated with the density, and the refractive index is negatively correlated with the transmittance, this solution can reduce the weight and improve the transmittance of the lens in the eyeglass module with the same field of view angle; at the same time, it can reduce the size of the lens. A larger coupling-out grating area is required for a single-sided lens to propagate the full field of view angle. The coupling-out grating area can be greatly reduced for only propagating a partial (for example, half-side) field of view angle, thereby reducing the lens profile and volume, and further reducing the weight.

[0032] It should be understood that the content described in this section is not intended to identify the key or important features of the embodiments of the present invention, nor is it intended to limit the scope of the present invention. Other features of the present invention will become easily understood through the following description. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the following briefly introduces the drawings required for use in the description of the embodiments. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0034] Figure 1 A schematic structural diagram of a diffraction optical waveguide provided for the implementation of the utility model;

[0035] Figure 2A schematic structural diagram of a diffraction optical waveguide provided in an embodiment of the present utility model;

[0036] Figure 3 A schematic diagram of a field of view transmission method of a near-eye display device provided in an embodiment of the present utility model;

[0037] Figure 4 A schematic diagram of a field of view transmission method of a near-eye display device provided in an embodiment of the present utility model;

[0038] Figure 5 A schematic structural diagram of another diffraction optical waveguide provided in an embodiment of the present utility model;

[0039] Figure 6 Schematic diagram of the wave vector space corresponding to the waveguide substrate;

[0040] Figure 7 Schematic diagram of the decomposition of the FOV of the entire image by the three-layer waveguide substrate;

[0041] Figure 8 A schematic structural diagram of a diffraction light waveguide corresponding to a near-eye display device provided by an embodiment of the present utility model;

[0042] Figure 9 To correspond Figure 8 Schematic diagram of FOV decomposition. DETAILED DESCRIPTION

[0043] In order to help those skilled in the art better understand the present invention, the following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the embodiments described are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts should fall within the scope of protection of the present invention.

[0044] It should be noted that the terms "first", "second", etc. in the specification and claims of the present invention and the above-mentioned drawings are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that the numbers used in this way can be interchanged where appropriate, so that the embodiments of the present invention described herein can be implemented in an order other than those illustrated or described herein. In addition, the terms "including" and "having" and any variations thereof are intended to cover non-exclusive inclusions. For example, a process, method, system, product or device that includes a series of steps or units is not necessarily limited to those steps or units clearly listed, but may include other steps or units that are not clearly listed or inherent to these processes, methods, products or devices.

[0045] In existing technologies, achieving wide-angle propagation of diffraction waveguides often requires a substrate material with a high refractive index. Since the refractive index of the material is positively correlated with the density, the diffraction waveguide is heavy, which is very unfavorable for the development of wearable devices such as VR or AR. In addition, to achieve wide-angle propagation, the area of ​​the coupling grating needs to be large, which is not conducive to the miniaturization of the device.

[0046] To address the aforementioned issues, an embodiment of the present invention provides a diffraction optical waveguide, comprising: at least one waveguide substrate having a refractive index within a range of 1.4 to 2.2; at least one coupling-in grating region within the waveguide substrate, the coupling-in grating region comprising a coupling-in grating having a period within a range of 150 nm to 700 nm; image light is incident upon the coupling-in grating region of the waveguide substrate, and image light corresponding to a portion of the field of view angle is diffracted into the waveguide substrate through the coupling-in grating, and is then coupled out to the human eye after being totally reflected within the waveguide substrate.

[0047] The incoupling grating region is used to receive externally incident image light. In a specific implementation, the diffraction waveguide further includes an outcoupling grating region, which includes an outcoupling grating for outcoupling light. In other embodiments, the diffraction waveguide may further include a turning grating region, which includes a turning grating for turning the transmission direction of the light beam.

[0048] For example, in the first embodiment, Figure 1 A structural diagram of a diffraction optical waveguide provided for the implementation of the present utility model, referring to Figure 1 The diffraction light waveguide includes a waveguide substrate 10 and a coupling grating 101. The coupling grating 101 includes a one-dimensional grating or a two-dimensional grating, which can be designed according to actual conditions during implementation. In this embodiment, by designing the period of the coupling grating 101, the image light a corresponding to a part of the field angle is diffracted by the coupling grating 101 and satisfies the total reflection condition in the waveguide substrate 10. After being totally reflected and transmitted in the waveguide substrate 10, it is coupled out to the human eye 20. The image light b corresponding to another part of the field angle is diffracted by the coupling grating 101 and does not satisfy the total reflection condition in the waveguide substrate 10 ( Figure 1 The figure schematically shows that this part of the light is directly emitted. In other embodiments, part of the light may be reflected multiple times and not emitted, or may not be diffracted into the waveguide substrate, so that it cannot be fully reflected and transmitted in the diffraction light waveguide, thereby achieving propagation of a partial field of view angle.

[0049] The technical solution of the embodiment of the present utility model enables the diffraction optical waveguide to realize the propagation of light with a partial field of view angle by setting a suitable coupling-in grating period. The superposition of at least two partial field of view angles forms a complete field of view angle, thereby realizing the propagation of a large field of view angle under low refractive index. Since the refractive index of the waveguide substrate is positively correlated with the density, and the refractive index is negatively correlated with the transmittance, this solution can reduce the weight and improve the transmittance of the lens in the eyeglass module with the same field of view angle; at the same time, it can reduce the size of the lens. A larger coupling-out grating area is required for a single-sided lens to propagate the full field of view angle. The coupling-out grating area can be greatly reduced for only propagating a partial (for example, half-side) field of view angle, thereby reducing the lens profile and volume, and further reducing the weight.

[0050] In one embodiment, optionally, continue to refer to Figure 1 The diffraction optical waveguide includes a waveguide substrate 10, and the period of the coupling grating 101 satisfies the following formula:

[0051]

[0052] Where D represents the period of the coupling grating 101, FOV represents the field of view, λ represents the wavelength of the incident light, and n a represents the refractive index of air, n g represents the refractive index of the waveguide substrate 10 .

[0053] It is understood that the diffraction waveguide provided in the embodiments of the present invention can form one lens in a binocular glasses module, with two diffraction waveguides forming the left and right lenses, respectively. By setting the coupling grating 101 to satisfy the above formula, the effect of transmitting the same-side field of view angle can be achieved by a single lens. For half of the image, the resulting period is larger, so that the diffracted light generated by half of the field of view passing through the coupling grating 101 does not meet the conditions for total internal reflection and cannot enter the waveguide for total internal reflection transmission. That is, only the left half of the image can be transmitted in the waveguide of the left lens, and only the right half of the image can be transmitted in the waveguide of the right lens. In other embodiments, a diffraction waveguide can also form the entire lens of a binocular glasses module, with two coupling gratings corresponding to the left and right eyes respectively set in the central region of the diffraction waveguide, so that only the left half of the image can be transmitted in the waveguide of the left half lens, and only the right half of the image can be transmitted in the waveguide of the right half lens.

[0054] In another embodiment, optionally, the diffractive optical waveguide includes a waveguide substrate 10, and the period of the coupling-in grating 101 satisfies the following formula:

[0055]

[0056] Where D represents the period of the coupling grating 101, FOV represents the field of view, λ represents the wavelength of the incident light, and n a represents the refractive index of air, n grepresents the refractive index of the waveguide substrate 10 .

[0057] A diffractive optical waveguide provided in an embodiment of the present invention can form a lens in a binocular glasses module. By setting an incoupling grating 101 to satisfy the above formula, the effect of transmitting the field of view of the opposite side through a single lens can be achieved. The resulting period of half the image is small, so that the diffracted light that does not pass through the grating at half the field of view cannot enter the waveguide and is transmitted by total reflection. In other embodiments, a diffractive optical waveguide can also form the entire lens of a binocular glasses module. Two incoupling gratings corresponding to the left and right eyes are set in the central region of the diffractive optical waveguide, respectively, so that the waveguide of the left half lens can only transmit the right half of the image, and the waveguide of the right half lens can only transmit the left half of the image.

[0058] Based on the diffractive optical waveguide provided in the first embodiment described above, the present invention provides a near-eye display device, wherein the near-eye display device provided in the present invention can be a VR or AR device. The near-eye display device includes a binocular glasses module, which includes a frame, an optical mechanism, and the diffractive optical waveguide provided in the above embodiment. For example, Figure 2 A structural diagram of a diffraction optical waveguide provided by an embodiment of the present utility model, referring to Figure 2 The diffraction optical waveguide includes a coupling-in grating area 100 located in the center and a first coupling-out grating area 200 and a second coupling-out grating area 300 located on both sides of the coupling-in grating area 100. The coupling-in grating area 100 can be provided with a first coupling-in grating 101a and a second coupling-in grating 101b. The image light emitted by the optical machine is incident on the coupling-in grating area 100. The light of the first part of the field of view angle is transmitted through the diffraction optical waveguide to the first coupling-out grating area 200 and coupled out to the user's left eye. The light of the second part of the field of view angle is transmitted through the diffraction optical waveguide to the second coupling-out grating area 300 and coupled out to the user's right eye.

[0059] In specific implementation, the first coupling grating 101a and the second coupling grating 101b can be set to satisfy formula (1), or the first coupling grating 101a and the second coupling grating 101b can be set to satisfy formula (2), which is not limited in the embodiment of the present invention.

[0060] Based on the diffraction light waveguide provided in the first type of implementation described above, in another embodiment, an embodiment of the present invention further provides a near-eye display device, comprising a binocular glasses module, the binocular glasses module comprising a frame, an optical machine, and two diffraction light waveguides provided in the above embodiments, the two diffraction light waveguides respectively forming a left eye lens and a right eye lens of the binocular glasses module.

[0061] It is understandable that in this embodiment, the near-eye display device may include two Figure 1 The diffraction waveguide shown in FIG. has only one coupling grating, and the two diffraction waveguides form the left and right lenses of the binocular glasses module, respectively. Optionally, the period of the coupling grating in the diffraction waveguide satisfies formula (1), with the left lens transmitting the image with the left half of the field of view to the user's left eye, and the right lens transmitting the image with the right half of the field of view to the user's right eye.

[0062] For example, Figure 3 A schematic diagram of a near-eye display device field of view transmission method provided by an embodiment of the present invention, with reference to Figure 3 The left eye lens transmits the left half of the field of view, and the right eye lens transmits the right half of the field of view, and the complete field of view is achieved after the image is combined.

[0063] In another embodiment, optionally, the period of the coupling grating in the diffraction waveguide satisfies formula (2), the left eye lens transmits the image of the right half field of view angle to the user's left eye, and the right eye lens transmits the image of the left half field of view angle to the user's right eye.

[0064] For example, Figure 4 A schematic diagram of a near-eye display device field of view transmission method provided by an embodiment of the present invention, with reference to Figure 4 The left eye lens transmits the right half of the field of view, and the right eye lens transmits the left half of the field of view, and the complete field of view is achieved after the image is combined.

[0065] Optionally, the coupling grating periods of the left-eye lens and the right-eye lens are the same and centered within the range of the calculation results.

[0066] By setting the coupling grating period of the left eye lens and the right eye lens to be the same and centered within the calculation structure range, it can be ensured that the left eye and the right eye observe exactly half of the field of view angle, and the field of view angle can be 30°-150°. The specific implementation can be designed according to actual conditions.

[0067] In the second type of embodiment, optionally, the diffraction optical waveguide includes at least two stacked waveguide substrates, and the periods of the coupled-in gratings in the at least two waveguide substrates are different; the at least two waveguide substrates include a first waveguide substrate and a second waveguide substrate, the first waveguide substrate transmits light of a first field of view angle, and the second waveguide substrate transmits light of a second field of view angle, and the light of the first field of view angle and the light of the second field of view angle are superimposed to form light of a superimposed field of view angle, which is coupled out to the human eye.

[0068] In this embodiment, the thickness of the waveguide substrate is in the range of 0.3 mm to 1.5 mm. By individually designing the period of the coupled grating on each waveguide substrate so that each one satisfies the propagation of a partial field of view angle, the superposition of these several small field of view angles can achieve a larger field of view angle.

[0069] For example, Figure 5 A structural diagram of another diffraction optical waveguide provided in an embodiment of the present invention is shown in FIG. Figure 5 The waveguide substrate 10 of the diffraction light waveguide includes a first waveguide substrate 11, a second waveguide substrate 12 and a third waveguide substrate 13. Each layer of the waveguide substrate bears part of the field of view, and finally the complete field of view is achieved by combining them.

[0070] Optionally, the field of view angle of each waveguide substrate transmission satisfies the following formula:

[0071]

[0072] Where FOV represents the field of view, λ represents the wavelength of light transmitted by the diffraction waveguide, and n a represents the refractive index of air, n g represents the refractive index of the waveguide substrate, Fh represents the decomposition height of the field angle in the vector domain, Fw represents the maximum decomposition width of the field angle in the vector domain, and n F Indicates the number of decompositions of the full field of view, n F is an integer and is obtained by rounding up the result of the formula, n F / 2 Indicates the number of decompositions of the half-field angle, n F / 2 It is an integer obtained by rounding up the result of the formula.

[0073] In this embodiment, the light field angle and the propagation change information of the light in the diffraction waveguide are converted from the spatial domain to the wave vector space for calculation. For example, Figure 6 Schematic diagram of the wave vector space corresponding to the waveguide substrate, refer to Figure 6 When the corresponding wave vector region of the beam lies within the inner circle, the beam propagates in air. When the corresponding wave vector region of the beam lies in the annular region between the inner and outer circles, the beam is transmitted by total internal reflection within the waveguide. When the corresponding wave vector region of the beam lies outside the outer circle, the beam effectively does not exist. In other words, only when the FOV lies between the outer large circle and the inner small circle can light from that FOV be coupled into the waveguide for transmission. In other words, the FOV within the range of height Fh and width Fw can be coupled into the waveguide base for transmission. Figure 7 This is a schematic diagram showing the decomposition of the entire image's FOV by three layers of waveguide substrates. The second, third, and fourth images represent how different waveguide substrates transmit portions of the FOV, each contributing to the completed FOV in the first image. By designing each layer of the waveguide substrate to satisfy Equation (3) and then adjusting the period of the coupled-in grating accordingly, the different layers of the waveguide substrate can each contribute to a portion of the FOV, ultimately synthesizing the complete FOV.

[0074] Based on the diffraction light waveguide provided by the second type of implementation, an embodiment of the present invention provides a near-eye display device, including a monocular glasses module, the monocular glasses module including a frame, an optical machine and the diffraction light waveguide provided in the above embodiment, the waveguide substrates of different layers in the diffraction light waveguide transmit light of a partial field of view angle to synthesize a complete field of view angle.

[0075] Based on the diffraction optical waveguide provided by the second type of implementation, an embodiment of the present utility model also provides a near-eye display device, including a binocular glasses module, a binocular glasses module frame, an optical machine and the diffraction optical waveguides provided by the two above embodiments, the two diffraction optical waveguides respectively form the left eye lens and the right eye lens of the binocular glasses module, the waveguide substrates of different layers in the left eye lens transmit light of part of the field of view angle, and the left eye lens is synthesized to achieve the field of view angle of half side, the waveguide substrates of different layers in the right eye lens transmit light of part of the field of view angle, and the right eye lens is synthesized to achieve the field of view angle of the other half side, and the left eye lens and the right eye lens achieve a complete field of view angle after the image is combined.

[0076] For example, Figure 8 A schematic diagram of the structure of the diffraction light waveguide corresponding to the near-eye display device provided by the embodiment of the present invention, with reference to Figure 8 , the left-eye lens 300 and the right-eye lens 400 both schematically show two layers of waveguide substrates 10 . Figure 9 To correspond Figure 8 FOV decomposition diagram, refer to Figure 9 Image La represents the situation where the left FOV is decomposed by two layers of waveguide substrates, and images Lb and Lc respectively represent the situation where the two layers of waveguide substrates on the left transmit part of the FOV; Image Ra represents the situation where the right FOV is decomposed by two layers of waveguide substrates, and images Rb and Rc respectively represent the situation where the two waveguide substrates on the right transmit part of the FOV.

[0077] The near-eye display device provided by the embodiment of the present invention has the technical effect corresponding to the diffraction light waveguide, which will not be described in detail here.

[0078] The above specific embodiments do not limit the scope of protection of this utility model. Those skilled in the art will appreciate that various modifications, combinations, sub-combinations, and substitutions may be made based on design requirements and other factors. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of this utility model shall be included within the scope of protection of this utility model.

Claims

1. A diffraction optical waveguide, characterized in that: include: At least one waveguide substrate, wherein the refractive index of the waveguide substrate is in the range of 1.4 to 2.2; At least one coupling-in grating region located on the waveguide substrate, the coupling-in grating region comprising a coupling-in grating, and a period of the coupling-in grating is between 150 nm and 700 nm; The image light is incident on the coupling grating area of ​​the waveguide substrate, and the image light corresponding to a part of the field angle is diffracted into the waveguide substrate through the coupling grating, and is coupled out to the human eye after total reflection transmission in the waveguide substrate.

2. The diffractive optical waveguide according to claim 1, wherein The diffraction optical waveguide includes a waveguide substrate, and the period of the coupling-in grating satisfies the following formula: Where D represents the period of the coupling grating, FOV represents the field of view, λ represents the wavelength of the incident light, and n a represents the refractive index of air, n g represents the refractive index of the waveguide substrate.

3. The diffractive optical waveguide according to claim 1, wherein The diffraction optical waveguide includes a waveguide substrate, and the period of the coupling-in grating satisfies the following formula: Where D represents the period of the coupling grating, FOV represents the field of view, λ represents the wavelength of the incident light, and n a represents the refractive index of air, n g represents the refractive index of the waveguide substrate.

4. The diffractive optical waveguide according to claim 1, wherein The diffraction optical waveguide comprises at least two stacked waveguide substrates, wherein the periods of the coupling-in gratings in the at least two waveguide substrates are different; At least two of the waveguide substrates include a first waveguide substrate and a second waveguide substrate, the first waveguide substrate transmits light of a first field of view angle, the second waveguide substrate transmits light of a second field of view angle, the light of the first field of view angle and the light of the second field of view angle are superimposed to form light of a superimposed field of view angle, which is coupled out to the human eye.

5. The diffractive optical waveguide according to claim 4, characterized in that The field of view angle of each waveguide substrate transmission satisfies the following formula: Where FOV represents the field of view, λ represents the wavelength of light transmitted by the diffraction waveguide, and n a represents the refractive index of air, n g represents the refractive index of the waveguide substrate, Fh represents the decomposition height of the field angle in the vector domain, Fw represents the maximum decomposition width of the field angle in the vector domain, and n F Indicates the number of decompositions of the full field of view, n F is an integer and is obtained by rounding up the result of the formula, n F / 2 Indicates the number of decompositions of the half-field angle, n F / 2 It is an integer obtained by rounding up the result of the formula.

6. The diffractive optical waveguide according to claim 1, wherein: The coupling-in grating includes a one-dimensional grating or a two-dimensional grating.

7. A near-eye display device, characterized in that: The binocular glasses module includes a frame, an optical engine, and a diffraction optical waveguide according to any one of claims 1 to 3 or 6, wherein the diffraction optical waveguide includes a central coupling-in grating region and a first coupling-out grating region and a second coupling-out grating region located on both sides of the coupling-in grating region. The image light emitted by the optical engine is incident on the coupling-in grating region, and the light of the first part of the field of view angle is transmitted through the diffraction optical waveguide to the first coupling-out grating region and coupled out to the user's left eye. The light of the second part of the field of view angle is transmitted through the diffraction optical waveguide to the second coupling-out grating region and coupled out to the user's right eye.

8. A near-eye display device, characterized in that: The invention comprises a binocular glasses module, which comprises a frame, an optical mechanism and two diffraction light waveguides according to any one of claims 1 to 3 or 6, wherein the two diffraction light waveguides respectively form a left eye lens and a right eye lens of the binocular glasses module.

9. The near-eye display device according to claim 8, wherein: The period of the coupling grating in the diffraction waveguide satisfies The left eye lens transmits the image of the left half field of view angle to the user's left eye, and the right eye lens transmits the image of the right half field of view angle to the user's right eye.

10. The near-eye display device according to claim 8, wherein: The period of the coupling grating in the diffraction waveguide satisfies The left-eye lens transmits the image of the right half field of view angle to the user's left eye, and the right-eye lens transmits the image of the left half field of view angle to the user's right eye.

11. The near-eye display device according to claim 9 or 10, characterized in that: The coupling grating periods of the left-eye lens and the right-eye lens are the same and centered within the range of the calculated results.

12. A near-eye display device, characterized in that: The monocular lens module comprises a frame, an optical machine, and a diffraction optical waveguide as claimed in claim 1, 4, 5 or 6, wherein the waveguide substrates of different layers in the diffraction optical waveguide transmit light of partial field angles to synthesize a complete field angle.

13. A near-eye display device, characterized in that: The invention comprises a binocular glasses module, a binocular glasses module frame, an optical machine, and two diffraction optical waveguides as described in claim 1, 4, 5 or 6, wherein the two diffraction optical waveguides respectively form a left eye lens and a right eye lens of the binocular glasses module, the waveguide substrates of different layers in the left eye lens transmit light of a partial field of view angle, and the left eye lens is synthesized to achieve a field of view angle of half side, the waveguide substrates of different layers in the right eye lens transmit light of a partial field of view angle, and the right eye lens is synthesized to achieve a field of view angle of the other half side, and the left eye lens and the right eye lens achieve a complete field of view angle after the image is combined.

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