One-dimensional super grating structure, light guide device and optical module

Abstract

The embodiment of the invention provides a one-dimensional super grating structure, a light guide device and an optical module. Wherein the one-dimensional super grating structure comprises at least one one-dimensional grating, and a grating period of a single one-dimensional grating comprises at least two units which are used for regulating and controlling the diffraction efficiency of a target diffraction order or increasing the adjustable and controllable range of the diffraction efficiency. According to the optical scheme provided by the embodiment of the invention, the single-time diffraction efficiency or the overall diffraction efficiency under multiple times of diffraction can be regulated and controlled.

Description

Technical Field

[0001] The embodiments of the present application relate to the field of optical technology, and more specifically, relate to a one-dimensional supergrating structure, a light-guiding device, and an optical module. Background Art

[0002] Augmented Reality (AR) technology is an optical display composed of a micro display and optical elements. Without affecting the user's observation of the external environment, the image generated by the micro display is projected into the user's eyes, realizing the superposition and fusion of the real world and virtual images. It has great application prospects in education, entertainment, industry and other fields.

[0003] At present, diffraction optical waveguide is one of the mainstream technical solutions for realizing augmented reality. It uses the diffraction effect of micro-nano structures to couple in and out light, and combines the total reflection effect of transparent substrates to conduct light. In existing solutions, one-dimensional gratings are usually used as coupling elements in waveguides. The manufacturing process of one-dimensional gratings is relatively simple, and they can be mass-produced through common photolithography and etching processes, or nanoimprinting processes. However, as a coupling device, one-dimensional gratings have low single diffraction efficiency and multiple diffraction of some light rays, resulting in light loss, and low overall coupling efficiency. Summary of the invention

[0004] The purpose of this application is to provide a new technical solution for a one-dimensional supergrating structure, a light-guiding device and an optical module, which solves the problem of low single diffraction efficiency and light loss caused by multiple diffraction of some light rays in existing one-dimensional gratings.

[0005] In a first aspect, an embodiment of the present application provides a one-dimensional supergrating structure. The one-dimensional supergrating structure includes at least one one-dimensional grating, and a grating period of a single one-dimensional grating includes at least two units, which are used to adjust the diffraction efficiency of a target diffraction order or increase the adjustable range of the diffraction efficiency.

[0006] Optionally, the one-dimensional grating is in the shape of a long strip, and the at least two units are arranged at intervals along the length direction of the one-dimensional grating;

[0007] By regulating at least one of the number, shape, size and position of the units, the diffraction efficiency of the corresponding one-dimensional grating can be improved or suppressed.

[0008] Optionally, a single one-dimensional grating contains at least two units in a grating period, and can also be used to form an asymmetric diffraction structure.

[0009] Optionally, a grating period of a single one-dimensional grating includes a first unit and a second unit, and the first unit and the second unit are arranged at intervals in the length direction of the single one-dimensional grating; wherein the first unit and the second unit are in at least one of a triangle, a trapezoid and a polygon.

[0010] Optionally, the grating period of a single one-dimensional grating includes a first unit, a second unit and a third unit, and the first unit, the second unit and the third unit are arranged at intervals in the length direction of the single one-dimensional grating; wherein the first unit, the second unit and the third unit are in at least one of the shapes of a triangle, a trapezoid and a polygon.

[0011] Optionally, the shape of the unit includes a triangle, a trapezoid or a polygon.

[0012] In a second aspect, an embodiment of the present application provides a light guide device. The light guide device includes a substrate and an incoupling region and an outcoupling region disposed on the substrate;

[0013] The coupling-in region is used to couple light and can make the light propagate to the coupling-out region by total reflection in the substrate; wherein the light is coupled into the coupling-in region at different incident angles;

[0014] The outcoupling region is used to outcouple the light propagating to the outcoupling region;

[0015] The coupling-in region and / or the coupling-out region has a one-dimensional supergrating structure as described in the first aspect.

[0016] Optionally, the one-dimensional supergrating structure includes a plurality of one-dimensional gratings, and a grating period of any one-dimensional grating includes at least two units, and each of the units is arranged obliquely or vertically relative to the substrate.

[0017] Optionally, when the one-dimensional supergrating structure is present in the coupling-in region, the light coupled into the coupling-in region may undergo at least one diffraction behavior after encountering the one-dimensional supergrating structure, and the diffraction light formed by each diffraction propagates to the decoupling region in a total reflection state in the substrate, and the diffraction efficiency of the diffraction light formed by each diffraction can be regulated by the one-dimensional supergrating structure.

[0018] Optionally, when the outcoupling region has the one-dimensional supergrating structure, the one-dimensional supergrating structure is located in a target region in the outcoupling region, and the one-dimensional supergrating structure is configured to suppress the diffraction efficiency of the target region.

[0019] Optionally, the light guiding device is a diffraction light waveguide device.

[0020] In a third aspect, an embodiment of the present application provides an optical module. The optical module includes:

[0021] The light guiding device according to the second aspect; and

[0022] An optical machine is used to project light or an image into the light guiding device.

[0023] The beneficial effects of this application are:

[0024] According to an embodiment of the present application, a one-dimensional supergrating structure is provided. Compared with a conventional one-dimensional grating, each grating period of the one-dimensional supergrating structure in the present application is designed to include at least two units. By increasing the number of units in each grating period, the single diffraction efficiency and the overall diffraction efficiency under multiple diffraction can be regulated, which can solve the problems of low single diffraction efficiency and light loss caused by multiple diffraction of part of the light in the conventional one-dimensional grating.

[0025] Other features and advantages of the present specification will become apparent from the following detailed description of exemplary embodiments of the present specification with reference to the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] The accompanying drawings, which are incorporated in and constitute a part of the specification, illustrate embodiments of the specification and, together with the description, serve to explain the principles of the specification.

[0027] Figure 1 One of the cross-sectional views of the one-dimensional supergrating structure provided in the embodiment of the present application;

[0028] Figure 2 A second cross-sectional view of a one-dimensional supergrating structure provided in an embodiment of the present application;

[0029] Figure 3 A third cross-sectional view of a one-dimensional supergrating structure provided in an embodiment of the present application;

[0030] Figure 4 A fourth cross-sectional view of a one-dimensional supergrating structure provided in an embodiment of the present application;

[0031] Figure 5 A fifth cross-sectional view of a one-dimensional supergrating structure provided in an embodiment of the present application;

[0032] Figure 6 The sixth cross-sectional view of the one-dimensional supergrating structure provided in the embodiment of the present application;

[0033] Figure 7 The seventh cross-sectional view of the one-dimensional supergrating structure provided in the embodiment of the present application;

[0034] Figure 8 An eighth cross-sectional view of a one-dimensional supergrating structure provided in an embodiment of the present application;

[0035] Fig. 9 A ninth cross-sectional view of a one-dimensional supergrating structure provided in an embodiment of the present application;

[0036] Fig.10 A light propagation path diagram of light coupled into the light guide device provided in an embodiment of the present application;

[0037] Fig.11 This is the diffraction efficiency diagram of a conventional one-dimensional straight grating when used as a transmission-type coupling grating;

[0038] Fig.12 One of the diffraction efficiency diagrams of the one-dimensional supergrating structure provided in the embodiment of the present application when used as a transmission-type coupling grating;

[0039] Fig.13 A second diffraction efficiency diagram of the one-dimensional supergrating structure provided in an embodiment of the present application when used as a transmission-type coupling-in grating;

[0040] Fig.14 A graph of coupling efficiency of single and multiple diffractions when the one-dimensional supergrating structure provided in the embodiment of the present application is applied in the coupling region;

[0041] Fig.15 This is the diffraction efficiency diagram of a conventional one-dimensional straight grating when used as a reflective outcoupling grating;

[0042] Fig.16 This is the diffraction efficiency diagram when the one-dimensional tilted grating is used as a reflective outcoupling grating;

[0043] Fig.17 A diffraction efficiency diagram of the one-dimensional supergrating structure provided in an embodiment of the present application when used as a reflective outcoupling grating.

[0044] Description of reference numerals:

[0045] 1. One-dimensional grating; 2. Unit; 3. Substrate; 4. Coupling region. DETAILED DESCRIPTION

[0046] Various exemplary embodiments of the present application will now be described in detail with reference to the accompanying drawings. It should be noted that unless otherwise specifically stated, the relative arrangement of components and steps, numerical expressions and numerical values ​​set forth in these embodiments do not limit the scope of the present application.

[0047] The following description of at least one exemplary embodiment is merely illustrative in nature and is in no way intended to limit the present application, its application, or uses.

[0048] Techniques and equipment known to ordinary technicians in the relevant art may not be discussed in detail, but where appropriate, the techniques and equipment should be considered part of the specification.

[0049] In all examples shown and discussed herein, any specific values ​​should be interpreted as merely exemplary and not limiting. Therefore, other examples of the exemplary embodiments may have different values.

[0050] It should be noted that like reference numerals and letters refer to similar items in the following figures, and therefore, once an item is defined in one figure, it need not be further discussed in subsequent figures.

[0051] The one-dimensional supergrating structure, light-guiding device and optical module provided in the embodiments of the present application are described in detail below in conjunction with the accompanying drawings.

[0052] According to an embodiment of the present application, a one-dimensional supergrating structure is provided. Figures 1 to 9 The one-dimensional supergrating structure includes at least one one-dimensional grating 1, and a single one-dimensional grating 1 contains at least two units 2 in a grating period, so as to adjust the diffraction efficiency of the target diffraction order or increase the adjustable range of the diffraction efficiency.

[0053] According to the one-dimensional supergrating structure provided by the above embodiment, compared with the conventional one-dimensional grating, an additional unit 2 is introduced into each grating period of the one-dimensional supergrating structure, so that the grating period of a single one-dimensional grating 1 can contain two or more of the units 2 in total. By increasing the number of units 2, the design can have more degrees of freedom in regulating the diffraction efficiency of a specific diffraction order, or can achieve a larger diffraction efficiency regulation range.

[0054] For example, the diffraction efficiency of a certain level (such as +1 level) of a conventional one-dimensional grating can only be adjusted within the range of 20% to 80%. However, the one-dimensional supergrating structure provided in the embodiment of the present application can achieve a wider range of diffraction efficiency adjustment than 20% to 80%. The one-dimensional supergrating structure can be used to achieve a diffraction efficiency adjustment between 1% and 99%, which achieves a wider range of diffraction efficiency adjustment.

[0055] The one-dimensional supergrating structure provided by the above embodiment can be applied to a diffractive optical waveguide or other types of diffractive optical elements.

[0056] For example, the one-dimensional supergrating structure can be applied to a diffraction optical waveguide lens.

[0057] It should be noted that the one-dimensional supergrating structure can be used in the coupling-in area, and of course can also be used in certain functional areas, and has a wide range of applications.

[0058] Specifically, when the one-dimensional supergrating structure is applied to a diffraction optical waveguide lens and used as a coupling grating, a higher coupling efficiency can be achieved, thereby further improving the performance.

[0059] Specifically, when the one-dimensional supergrating structure is applied to a diffraction optical waveguide lens and used as certain functional areas, such as in a decoupling area, it can be arranged between the two-dimensional grating and the one-dimensional grating in the decoupling area, and the diffraction efficiency can be appropriately reduced by regulation, so that the overall performance can be optimized by reducing the local diffraction efficiency.

[0060] Optionally, the one-dimensional supergrating structure can be mass-produced using general lithography and etching, or nanoimprinting technology.

[0061] According to an embodiment of the present application, a one-dimensional metagrating structure (1D metagrating) is provided. Compared with a conventional one-dimensional grating, each grating period of the one-dimensional metagrating structure includes at least two units. By increasing the number of units in each grating period, the single diffraction efficiency and the overall diffraction efficiency under multiple diffraction can be regulated. This can solve the problems of low single diffraction efficiency and light loss caused by multiple diffraction of part of the light in the conventional one-dimensional grating.

[0062] In some examples of the present application, the one-dimensional grating 1 is in the shape of a long strip, and the at least two units 2 are arranged at intervals along the length direction of the one-dimensional grating 1, see Figures 1 to 9 ; wherein, by regulating at least one of the number, shape, size and position of the units 2, the diffraction efficiency of the corresponding one-dimensional grating 1 can be improved or suppressed.

[0063] The one-dimensional supergrating structure provided in the embodiment of the present application may include a plurality of one-dimensional gratings 1 arranged in sequence and spaced apart from each other. The one-dimensional grating 1 is a strip grating. In the one-dimensional supergrating structure, the number of units 2 is increased in a grating period of a single one-dimensional grating 1, so that the number of units 2 contained in each period is two or more, rather than a single unit 2.

[0064] The diffraction efficiency of the entire grating structure can be regulated by designing the units 2 included in the grating period of a single one-dimensional grating 1. Specifically, the factors to be considered when adding the units 2 in the grating period of a single one-dimensional grating 1 include the number of units 2, their own size and shape, and the position in a single grating period (the relative positions of multiple units 2 can be adjusted as needed) mentioned in the above example. This allows the formed one-dimensional supergrating structure to have a higher degree of freedom in design and a wider range of regulating diffraction efficiency. Compared to conventional one-dimensional gratings, the one-dimensional supergrating structure can provide more flexible diffraction efficiency.

[0065] In some examples of the present application, a single one-dimensional grating 1 includes at least two units 2 in a grating period, and can also be used to form an asymmetric diffraction structure.

[0066] According to the above example, a single one-dimensional grating 1 contains at least two units 2 in its grating period. Different diffraction structures can be formed by designing each unit 2 differently. In this way, when light encounters a one-dimensional supergrating structure, it can form different diffraction behaviors in different dimensions, thereby forming an asymmetric diffraction response, which can be applicable to some functional areas on a diffraction optical element.

[0067] Optionally, see Figures 1 to 4 , the one-dimensional supergrating structure includes multiple one-dimensional gratings 1; wherein, the grating period of a single one-dimensional grating 1 includes two units 2, namely a first unit and a second unit, and the first unit and the second unit are arranged at intervals in the length direction of the single one-dimensional grating 1; wherein, the first unit and the second unit are in at least one of the shapes of a triangle, a trapezoid and a polygon.

[0068] See also Figures 1 to 4 , a single one-dimensional grating 1 may include two units 2 within a grating period, namely, the first unit and the second unit in the above example; wherein the first unit and the second unit may be completely the same or different. In addition, the first unit and the second unit may be arranged vertically or tilted, and this application does not limit this.

[0069] For example, see Figure 1 The one-dimensional supergrating includes a plurality of one-dimensional gratings 1, wherein the grating period of any one-dimensional grating 1 includes two units 2 of the same height and width. At this time, the two units 2 can both be the same rectangle, which is a kind of quadrilateral.

[0070] For example, see Figure 2 The one-dimensional supergrating includes a plurality of one-dimensional gratings 1, wherein the grating period of any one-dimensional grating 1 includes two units 2 of the same width and different heights. At this time, the two units 2 can both be rectangular, but the height dimensions of the two units are designed differently.

[0071] For example, see Figure 3 The one-dimensional supergrating includes a plurality of one-dimensional gratings 1, wherein the grating period of any one-dimensional grating 1 includes two units 2 of the same height and different widths. At this time, the two units 2 can both be rectangular, but the width dimensions of the two units are designed differently.

[0072] For example, see Figure 4The one-dimensional supergrating includes a plurality of one-dimensional gratings 1, wherein the grating period of any one-dimensional grating 1 includes two units 2 of different heights and widths. In this case, the two units 2 may both be rectangular, but their heights and widths are designed to be different.

[0073] That is to say, the two units 2 included in each grating period of the one-dimensional grating 1 may be completely identical, or different, or partially identical, and the specific adjustment may be made according to the situation.

[0074] In addition, the distance between the two units 2 in each grating period can be adjusted, that is, the relative position of the two units 2 can be adjusted, which can also be used to control the diffraction efficiency of the target diffraction order or increase the adjustable range of the diffraction efficiency.

[0075] Optionally, see Figures 5 to 9 , a single one-dimensional grating 1 includes three units 2 in a grating period, namely a first unit, a second unit and a third unit, and the first unit, the second unit and the third unit are arranged at intervals in the length direction of the single one-dimensional grating 1; wherein the first unit, the second unit and the third unit are in at least one of a triangle, a trapezoid and a polygon.

[0076] See also Figures 5 to 9 The grating period of a single one-dimensional grating 1 may also include three units 2, namely the first unit, the second unit and the third unit in the above example. Under this design, the number of units 2 is also increased in the grating period of a single one-dimensional grating 1, thereby forming a one-dimensional supergrating structure.

[0077] The first unit, the second unit and the third unit may be identical or different. In addition, the first unit, the second unit and the third unit may be arranged vertically or tilted, and this application does not limit this.

[0078] For example, see Figure 5 The one-dimensional supergrating includes a plurality of one-dimensional gratings 1, wherein the grating period of any one-dimensional grating 1 includes three units 2 of different heights and widths. At this time, the three units 2 can all be rectangular, but the height and width dimensions of the three units are designed to be different.

[0079] For example, see Figure 6 The one-dimensional supergrating includes a plurality of one-dimensional gratings 1, wherein the grating period of any one-dimensional grating 1 includes three units 2 of different heights and widths, and each of the units 2 is arranged in an inclined manner. At this time, the three units 2 are designed as parallelograms, and the height and width dimensions are designed to be different.

[0080] For example, see Figure 7 The one-dimensional supergrating includes a plurality of one-dimensional gratings 1, wherein the grating period of any one-dimensional grating 1 includes three units 2 of different heights, different widths, and different shapes. At this time, the first unit and the second unit can be tilted and parallelogram-shaped, but the width, height, and tilt angle of the two can be designed to be different, and the third unit can be designed to be rectangular and different from the first unit and the second unit.

[0081] For example, see Figure 8 The one-dimensional supergrating includes a plurality of one-dimensional gratings 1, wherein the grating period of any one-dimensional grating 1 contains three units 2 of different heights, different widths and the same shape. At this time, the three units can be designed as trapezoids, and the sizes of the three units are designed to be different.

[0082] For example, see Fig. 9 The one-dimensional supergrating includes a plurality of one-dimensional gratings 1, wherein the grating period of any one-dimensional grating 1 contains three units 2 of different heights, different widths, and different shapes. At this time, the third unit is, for example, trapezoidal and tilted, while the first unit and the second unit can be trapezoidal and have different sizes.

[0083] It should be noted that the grating period of a single one-dimensional grating 1 may also include more than three units 2. The shapes, sizes and relative positions of the multiple units 2 may be flexibly designed as required, and this application does not impose any restrictions thereon.

[0084] In some examples of this application, see Figures 1 to 9 The shape of the unit 2 includes a triangle, a trapezoid or a polygon.

[0085] The one-dimensional supergrating provided in the embodiment of the present application can provide higher diffraction efficiency and asymmetric diffraction response for different incident light angles compared to conventional one-dimensional gratings.

[0086] The application of a one-dimensional supergrating in the coupling region as a coupling grating is used as an example for explanation.

[0087] Fig.11 The diffraction efficiency of a conventional one-dimensional grating as a transmissive coupling grating is shown in FIG. Fig.12 It can be seen from the diffraction efficiency curve shown on the right that the +1T and -1T order diffraction efficiency curves are symmetrical about the incident angle = 0, which is not conducive to sufficient coupling of energy.

[0088] In fact, it is usually hoped that the diffraction efficiency in the +1T direction is as high as possible, and the diffraction efficiency in the -1T direction is as low as possible.

[0089] Fig.12FIG. 1 shows a diffraction efficiency diagram of a one-dimensional supergrating structure provided by an embodiment of the present application when used as a transmission coupling grating. Fig.12 As can be seen from the one-dimensional supergrating structure shown on the left, a single grating period of the one-dimensional supergrating structure includes two units 2 with different widths and heights. Fig.12 The diffraction efficiency curve shown on the right shows that when the one-dimensional supergrating is used as a transmission coupling grating, the +1T and -1T diffraction efficiency curves are asymmetric about the incident angle = 0, and the diffraction efficiency in the +1T direction is improved.

[0090] Fig.13 FIG. 2 shows a diffraction efficiency diagram of another one-dimensional supergrating structure provided in an embodiment of the present application when used as a transmission coupling grating. Fig.13 As can be seen from the one-dimensional supergrating structure shown on the left, a single grating period of the one-dimensional supergrating structure includes two units 2 of different widths but the same height. Fig.13 It can be seen from the diffraction efficiency curve shown on the right that when the one-dimensional supergrating is used as a transmission coupling grating, the +1T and -1T diffraction efficiency curves are asymmetric about the incident angle = 0, and the diffraction efficiency in the +1T direction is improved.

[0091] Of course, the one-dimensional supergrating structure provided in the embodiment of the present application is not limited to being applied in the coupling-in region, but can also be applied in the coupling-out region.

[0092] See also Fig.14 , Fig.14 The coupling efficiency spectra of single and multiple diffraction when the one-dimensional supergrating structure provided in the embodiment of the present application is applied in the coupling zone are shown. It can be seen that when the one-dimensional supergrating structure is used as a coupling device, the overall coupling efficiency of single and multiple diffraction is improved.

[0093] According to another embodiment of the present application, a light guide device is provided. Fig.10 , the light-guiding device comprises a substrate 3 and an in-coupling region 4 and an out-coupling region arranged on the substrate 3. The in-coupling region 4 is used to couple light and can make the light fully reflected in the substrate 3 and propagate to the out-coupling region, wherein the light is coupled into the in-coupling region 4 at different incident angles. The out-coupling region is used to couple out the light propagated to the out-coupling region. The in-coupling region 4 and / or the out-coupling region have the one-dimensional super grating structure as described above.

[0094] See also Fig.10 , Fig.10The figure shows the light propagation path of the light coupled into the substrate 3 through the coupling-in region 4, which undergoes a diffraction at the position of the coupling-in region 4. After being modulated at position A, the light is reflected at position B until it encounters the coupling-in region 4 again and undergoes diffraction, and then is totally reflected at position C and propagates to the coupling-out region. It should be noted that the coupling-out region is Fig.11 Not shown in FIG.

[0095] According to the light-guiding device provided in the embodiment of the present application, it can be, for example, a diffraction light waveguide, which can be suitable for application in wearable devices, wherein the wearable devices include head mounted display devices (Head mounted display, HMD), such as AR head mounted display devices.

[0096] In some examples of the present application, the light guiding device is a diffractive light waveguide.

[0097] Wherein, the substrate 3 is a waveguide substrate.

[0098] Of course, the light guiding device may also be a diffractive optical element in other forms.

[0099] In some examples of the present application, the one-dimensional supergrating structure includes a plurality of one-dimensional gratings 1, wherein the grating period of any one-dimensional grating 1 includes at least two units 2, and each of the units 2 is arranged obliquely or vertically relative to the substrate 3, which can be respectively referred to as Figures 1 to 9 .

[0100] In some examples of this application, see Fig.10 When the coupling-in region 4 has the one-dimensional supergrating structure, the light coupled into the coupling-in region 4 may undergo at least one diffraction behavior after encountering the one-dimensional supergrating structure, and the diffraction light formed by each diffraction is propagated to the coupling-out region in a total reflection state in the substrate 3, and the diffraction efficiency of the diffraction light formed by each diffraction can be regulated by the one-dimensional supergrating structure.

[0101] According to the above example, the one-dimensional super grating structure itself is used as a coupling device and is arranged in the coupling region 4, which can improve the single diffraction efficiency, and even if some light rays are diffracted multiple times, there will be no significant light loss. The one-dimensional super grating structure can improve the overall coupling efficiency, overcome the defects of conventional one-dimensional gratings, and further improve the diffraction optical performance.

[0102] Fig.11 The diffraction efficiency of a conventional one-dimensional grating as a transmissive coupling grating is shown in FIG. Fig.11 It can be seen from the diffraction efficiency curve shown on the right that the +1T and -1T order diffraction efficiency curves are symmetrical about the incident angle = 0, which is not conducive to sufficient coupling of energy.

[0103] Fig.12 FIG. 1 shows a diffraction efficiency diagram of a one-dimensional supergrating structure provided by an embodiment of the present application when used as a transmission coupling grating. Fig.12 As can be seen from the one-dimensional supergrating structure shown on the left, a single grating period of the one-dimensional supergrating structure includes two units 2 with different widths and heights. Fig.12 The diffraction efficiency curve shown on the right shows that when the one-dimensional supergrating is used as a transmission coupling grating, the +1T and -1T diffraction efficiency curves are asymmetric about the incident angle = 0, and the diffraction efficiency in the +1T direction is improved.

[0104] Fig.13 FIG. 2 shows a diffraction efficiency diagram of another one-dimensional supergrating structure provided in an embodiment of the present application when used as a transmission coupling grating. Fig.13 As can be seen from the one-dimensional supergrating structure shown on the left, a single grating period of the one-dimensional supergrating structure includes two units 2 of different widths but the same height. Fig.13 It can be seen from the diffraction efficiency curve shown on the right that when the one-dimensional supergrating is used as a transmission coupling grating, the +1T and -1T diffraction efficiency curves are asymmetric about the incident angle = 0, and the diffraction efficiency in the +1T direction is improved.

[0105] In some examples of the present application, when the one-dimensional supergrating structure is present in the outcoupling region, the one-dimensional supergrating structure is located in a target region in the outcoupling region, and the one-dimensional supergrating structure is configured to suppress the diffraction efficiency of the target region.

[0106] Fig.15 The figure shows the diffraction efficiency of a conventional one-dimensional straight grating as a reflective outcoupling grating. Fig.15 It can be seen from the diffraction efficiency curve shown on the right that when a conventional one-dimensional straight grating is used as a reflective outcoupling grating, the -1T order diffraction corresponds to leakage light, and it is hoped that the efficiency is as low as possible.

[0107] Fig.16 The diffraction efficiency of a one-dimensional tilted grating as a reflective outcoupling grating is shown. Fig.16 From the diffraction efficiency curve shown on the right, it can be seen that the -1T order diffraction efficiency (light leakage) is reduced.

[0108] Fig.17 The diffraction efficiency of a one-dimensional tilted grating as a reflective outcoupling grating is shown. Fig.17 It can be seen from the diffraction efficiency curve shown on the right that for the one-dimensional tilted supergrating, its -1T-order diffraction efficiency (light leakage) is further reduced.

[0109] It should be noted that the decoupling zone can be designed as a partition, the middle area of ​​the decoupling zone can adopt a two-dimensional grating, and the edge area can adopt a one-dimensional grating. A transition grating area with a diffraction efficiency between the two can be introduced between the two-dimensional grating area and the one-dimensional grating area, which can introduce the one-dimensional super grating structure provided in the embodiment of the present application, which has a lower diffraction efficiency than the two-dimensional grating, so that the local diffraction efficiency can be further reduced to achieve the optimization of the overall performance. In other words, by introducing the one-dimensional super grating structure provided in the embodiment of the present application into the decoupling zone, the light energy in the entire decoupling zone can be more flexibly and reasonably distributed from the middle to the edge, and a gradual transition of light energy is formed in the decoupling zone, which can improve the diffraction efficiency of the decoupling zone, thereby improving the imaging quality.

[0110] According to another aspect of an embodiment of the present application, an optical module is provided.

[0111] The optical module includes the light guide device and an optical engine as described above; wherein the optical engine is used to project light or an image into the light guide device.

[0112] The imaging light emitted by the optical machine can cover the entire coupling-in area 4 .

[0113] The imaging light emitted by the optical machine may be monochromatic light or polychromatic light.

[0114] The optical module provided in the embodiments of the present application can be used in, for example, a head-mounted display device, specifically in AR glasses or an AR helmet.

[0115] The specific implementation of the light guide device and the optical module of the embodiment of the present application can refer to the above-mentioned light guide device embodiments, so it at least has all the beneficial effects brought by the technical solutions of the above-mentioned embodiments, which will not be repeated here one by one.

[0116] The above embodiments focus on the differences between the various embodiments. As long as the different optimization features between the various embodiments are not contradictory, they can be combined to form a better embodiment. Considering the simplicity of the text, they will not be repeated here.

[0117] Although some specific embodiments of the present application have been described in detail by way of example, it should be understood by those skilled in the art that the above examples are only for illustration, not for limiting the scope of the present application. It should be understood by those skilled in the art that the above embodiments may be modified without departing from the scope and spirit of the present application. The scope of the present application is defined by the appended claims.

Claims

1. A one-dimensional supergrating structure, characterized in that: It comprises at least one one-dimensional grating (1), and a grating period of a single one-dimensional grating (1) comprises at least two units (2) for adjusting the diffraction efficiency of a target diffraction order or increasing the adjustable range of the diffraction efficiency.

2. The one-dimensional supergrating structure according to claim 1, characterized in that: The one-dimensional grating (1) is in the shape of a long strip, and the at least two units (2) are arranged at intervals along the length direction of the one-dimensional grating (1); By regulating at least one of the number, shape, size and position of the units (2), the diffraction efficiency of the corresponding one-dimensional grating (1) can be improved or suppressed.

3. The one-dimensional supergrating structure according to claim 1, characterized in that: A single one-dimensional grating (1) contains at least two units (2) within a grating period, and can also be used to form an asymmetric diffraction structure.

4. The one-dimensional supergrating structure according to any one of claims 1 to 3, characterized in that: A grating period of a single one-dimensional grating (1) comprises a first unit and a second unit, wherein the first unit and the second unit are arranged at intervals in the length direction of the single one-dimensional grating (1); wherein the first unit and the second unit are in at least one of a triangular, a trapezoidal and a polygonal shape.

5. The one-dimensional supergrating structure according to any one of claims 1 to 3, characterized in that: The grating period of a single one-dimensional grating (1) comprises a first unit, a second unit and a third unit, wherein the first unit, the second unit and the third unit are arranged at intervals in the length direction of the single one-dimensional grating (1); wherein the first unit, the second unit and the third unit are in at least one of the shapes of a triangle, a trapezoid and a polygon.

6. The one-dimensional supergrating structure according to any one of claims 1 to 3, characterized in that: The shape of the unit (2) includes a triangle, a trapezoid or a polygon.

7. A light guide device, characterized in that: It comprises a substrate (3) and a coupling-in region (4) and a coupling-out region arranged on the substrate (3); The coupling-in region (4) is used to couple light and enable the light to be totally reflected in the substrate (3) and propagate to the coupling-out region; wherein the light is coupled into the coupling-in region (4) at different incident angles; The outcoupling region is used to outcouple the light propagating to the outcoupling region; The coupling-in region (4) and / or the coupling-out region has a one-dimensional supergrating structure as claimed in any one of claims 1 to 6.

8. The light guide device according to claim 7, characterized in that: The one-dimensional supergrating structure comprises a plurality of one-dimensional gratings (1), wherein a grating period of any one-dimensional grating (1) comprises at least two units (2), and each of the units (2) is arranged obliquely or vertically relative to the substrate (3).

9. The light guide device according to claim 7, characterized in that: When the coupling-in region (4) has the one-dimensional supergrating structure, the light coupled into the coupling-in region (4) may undergo at least one diffraction behavior after encountering the one-dimensional supergrating structure, and the diffracted light formed by each diffraction is propagated to the coupling-out region in a state of total reflection in the substrate (3), and the diffraction efficiency of the diffracted light formed by each diffraction can be adjusted by the one-dimensional supergrating structure.

10. The light guide device according to claim 7, characterized in that: When the outcoupling region has the one-dimensional supergrating structure, the one-dimensional supergrating structure is located in a target region in the outcoupling region, and the one-dimensional supergrating structure is configured to suppress the diffraction efficiency of the target region.

11. The light guide device according to claim 10, characterized in that: The light guiding device is a diffractive light wave guiding device.

12. An optical module, characterized in that: include: The light guide device according to any one of claims 7 to 11; as well as An optical machine is used to project light or an image into the light guiding device.

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