Light guide device and head-mounted display equipment

Abstract

The embodiment of the invention provides a light guide device and head-mounted display equipment. Wherein the light guide device comprises a substrate, a coupling-in area, a coupling-out area and a pupil expanding area, the coupling-in area, the coupling-out area and the pupil expanding area are arranged on the substrate, the coupling-in area comprises two coupling-in gratings, the coupling-out area comprises two coupling-out gratings, and the pupil expanding area comprises two pupil expanding gratings; wherein the pupil expanding area is located between light paths of the coupling-in area and the coupling-out area, light coupled in from any coupling-in grating can be coupled out from the two coupling-out gratings after being modulated through the two pupil expanding gratings, and the two coupling-out gratings correspond to the left eye and the right eye respectively. The embodiment of the invention provides a scheme of a binocular-to-single light guide device, so that the optical efficiency and the image uniformity can be improved, and the imaging effect of waveguides and the like is improved.

Description

Technical Field

[0001] The embodiments of the present application relate to the field of optical imaging technology, and more specifically, to a light guide device and a head-mounted display device. Background Art

[0002] Optical waveguide elements are a form of light-guiding devices, and they are the core components of augmented reality (AR) devices. Optical waveguide elements mainly use the principle of total reflection to achieve light transmission. By combining with diffractive optical elements, they achieve directional conduction of light, and then guide the imaging light to the human eye, so that users can see the projected image. The grating is the most critical component in the diffractive optical waveguide element, which is responsible for coupling light in, out, and expanding the pupil. As far as the prior art is concerned, the current design of optical waveguide elements is based on monocular waveguides. During binocular imaging, the light in the two optical waveguide elements has no interaction, and the imaging quality is poor, which affects the user's visual experience. Summary of the invention

[0003] The purpose of this application is to provide a new technical solution for a light-guiding device and a head-mounted display device.

[0004] In a first aspect, the present application provides a light guide device. The light guide device includes a substrate and an incoupling region, an outcoupling region and a pupil expansion region arranged on the substrate, wherein the incoupling region includes two incoupling gratings, the outcoupling region includes two outcoupling gratings, and the pupil expansion region includes two pupil expansion gratings;

[0005] The pupil expansion area is located between the optical paths of the coupling-in area and the coupling-out area, and the light coupled in from any of the coupling-in gratings can be coupled out from the two coupling-out gratings after being modulated by the two pupil expansion gratings, and the two coupling-out gratings correspond to the left eye and the right eye respectively.

[0006] Optionally, the light-guiding device further includes an energy recovery zone, and the energy recovery zone is disposed on the substrate and adjacent to the pupil expansion zone, and the energy recovery zone is configured to receive part of the light modulated by the pupil expansion zone and reflect the part of the light to the outcoupling zone for outcoupling.

[0007] Optionally, the coupling-in grating and the coupling-out grating are one-dimensional gratings;

[0008] The pupil expansion grating is a two-dimensional grating, or a combination of at least two one-dimensional gratings.

[0009] Optionally, the energy recovery zone includes at least one seventh grating, and the seventh grating is a one-dimensional grating.

[0010] Optionally, the coupling-in area, the coupling-out area, the pupil expansion area and the energy recovery area are located on the same surface of the substrate;

[0011] The two coupling-in gratings are arranged on opposite sides of the pupil expansion area along a first direction R1, the two coupling-out gratings and the seventh grating are arranged on opposite sides of the pupil expansion area along a second direction R2, and the two coupling-out gratings are located on the same side of the pupil expansion area, and the first direction R1 and the second direction R2 form a preset angle.

[0012] Optionally, the two coupling-in gratings include a first grating and a second grating disposed at intervals, the two pupil expansion gratings include a third grating and a fourth grating disposed adjacently, the two coupling-out gratings include a fifth grating and a sixth grating disposed at intervals, and the seventh grating is disposed on a side of the two pupil expansion gratings away from the two coupling-out regions;

[0013] After the first light is coupled in by the first grating, a portion of the first light is propagated to the fifth grating for out-coupling after being expanded and turned by the third grating; another portion of the first light is propagated to the fourth grating, and is propagated to the sixth grating for out-coupling after being expanded and turned by the fourth grating; and another portion of the first light is modulated by the third grating and turned to propagate to the seventh grating, and is reflected by the seventh grating to be coupled out by the sixth grating.

[0014] Optionally, after the second light is coupled in by the second grating: a portion of the second light is propagated to the sixth grating for out-coupling after being expanded and turned by the fourth grating; another portion of the second light is propagated to the third grating, and is propagated to the fifth grating for out-coupling after being expanded and turned by the third grating; and another portion of the second light is modulated by the fourth grating and turned to propagate to the seventh grating, and is reflected by the seventh grating to be coupled out by the fifth grating.

[0015] Optionally, the third grating includes at least a first diffraction direction and a second diffraction direction, the first diffraction direction is used to deflect a first light ray coupled into the first grating and propagating to the third grating to the fifth grating, and the second diffraction direction is used to deflect a second light ray coupled into the second grating and propagating to the third grating to the fifth grating;

[0016] The fourth grating is identical to the third grating.

[0017] Optionally, the sum of the vectors of the first grating, the third grating and the fifth grating is zero, the sum of the vectors of the first grating, the fourth grating and the sixth grating is zero, and the sum of the vectors of the first grating, the third grating, the seventh grating and the sixth grating is zero.

[0018] Optionally, the sum of the vectors of the second grating, the fourth grating and the sixth grating is zero, the sum of the vectors of the second grating, the third grating and the fifth grating is zero, and the sum of the vectors of the second grating, the fourth grating, the seventh grating and the fifth grating is zero.

[0019] Optionally, a nose avoidance area is provided on the substrate, the pupil expansion area is located on one side of the nose avoidance area, the two coupling-in gratings are symmetrically arranged on opposite sides of the pupil expansion area and away from the nose avoidance area, and the two coupling-out gratings are arranged on opposite sides of the nose avoidance area and correspond to the left eye and the right eye respectively, so as to form an optical structure in which a single light guide device corresponds to two eyes.

[0020] Optionally, the light guiding device is a diffraction light waveguide.

[0021] In a second aspect, the present application provides a head mounted display device. The head mounted display device comprises:

[0022] shell;

[0023] two optical machines; and,

[0024] The light guide device as described in the first aspect;

[0025] The two optical machines and the two coupling gratings of the light guide device are arranged in a one-to-one correspondence. The beneficial effects of the present application are:

[0026] According to the light-guiding device provided in the embodiment of the present application, which is a binocular-view waveguide element, the fusion and improvement of two pupil-expanding gratings in the binocular-view waveguide element enable the light coupled in through the coupling grating on either side to not only satisfy the imaging of the waveguide on this side, but also to supplement and enhance the imaging of the waveguide on the other side, thereby improving the optical efficiency of the light-guiding device and the image uniformity of the final imaging as a whole, thereby improving the imaging effect of the light-guiding device, which is beneficial to improving the visual experience of the user.

[0027] 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

[0028] 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.

[0029] Figure 1 One of the structures and light propagation diagrams of a light guide device provided in one embodiment of the present application;

[0030] Figure 2 for Figure 1K-space diagram of the light guide device provided;

[0031] Figure 3 The second diagram of the structure and light propagation of the light guide device provided in one embodiment of the present application;

[0032] Figure 4 for Figure 3 K-space diagram of the provided light guide.

[0033] Reference numerals:

[0034] 1. First grating; 2. Second grating; 3. Third grating; 4. Fourth grating; 5. Fifth grating; 6. Sixth grating; 7. Seventh grating; 8. Base; 9. Nose bridge avoidance area;

[0035] 01. First light; 02. Second light. DETAILED DESCRIPTION

[0036] 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.

[0037] 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.

[0038] 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.

[0039] 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.

[0040] 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.

[0041] The light guide device and the head mounted display device provided in the embodiments of the present application are described in detail below with reference to the accompanying drawings.

[0042] According to one aspect of an embodiment of the present application, a light guide device is provided, and the light guide device is, for example, a diffractive light waveguide element, which can be suitable for use in an augmented reality AR device to transmit light emitted by a projection optical machine. The augmented reality AR device may include AR glasses or an AR helmet, and the embodiment of the present application does not limit the specific form of the head-mounted display device.

[0043] The light guide device proposed in the embodiment of the present application, see Figure 1 and Figure 3 The light-guiding device includes a substrate 8 and a coupling-in area, a coupling-out area and a pupil expansion area arranged on the substrate 8, and the coupling-in area includes two coupling-in gratings, the coupling-out area includes two coupling-out gratings, and the pupil expansion area includes two pupil expansion gratings; wherein the pupil expansion area is located between the optical paths of the coupling-in area and the coupling-out area, and the light coupled in from any of the coupling-in gratings can be coupled out from the two coupling-out gratings after being modulated by the two pupil expansion gratings, and the two coupling-out gratings correspond to the left eye and the right eye, respectively.

[0044] According to the light guide device provided in the above embodiment, see Figure 1 and Figure 3 , a coupling-in region, a coupling-out region and a pupil expansion region are arranged on a substrate 8, and the coupling-in region is designed to include two coupling-in gratings, for example Figure 1 and Figure 3 The first grating 1 and the second grating 2 shown in FIG. 1 are shown in FIG. 1 ; the outcoupling region is designed to include two outcoupling gratings, for example Figure 1 and Figure 3 The fifth grating 5 and the sixth grating 6 shown in FIG. 1 ; the pupil expansion area is designed to include two adjacent pupil expansion gratings, for example Figure 1 and Figure 3 The third grating 3 and the fourth grating 4 are shown in FIG. From the above-mentioned entire grating layout, the pupil expansion area can be located at the center of the substrate 8, for example, and the coupling-in area and the coupling-out area can be arranged around the pupil expansion area.

[0045] The two coupling gratings in the coupling region are provided with corresponding optical machines, for example, and the two coupling gratings on the substrate 8 can be bilaterally symmetrical, so that light for imaging display can be coupled into the left eye side and the right eye side of the user respectively. The embodiment of the present application provides an optical solution for a single light guide device corresponding to binoculars, that is, binocular imaging can be achieved through a single light guide device.

[0046] Specifically, the light guide device of the embodiment of the present application is shown in FIG. Figure 1 and Figure 3, the two coupling gratings in the coupling-in area can couple light into the left and right sides of the substrate 8, respectively, and the propagation paths of the light coupled in on the two sides are the same. The light coupled in by one of the coupling-in gratings on either side can be modulated together by the pupil expansion grating close to it and the pupil expansion grating far away from it, so that the light coupled in from the same side can be modulated to be coupled out by the two coupling-out gratings in the coupling-out area at the same time, so that the light energy of the light coupled out by any coupling-out grating can be compensated. Since each coupling-out grating corresponds to one eye of the user (left eye or right eye), the two coupling-out gratings correspond to the binoculars of the user. Based on this, when the coupling-in gratings on both sides couple in light at the same time, the imaging light of both eyes can be compensated at the same time.

[0047] For the traditional optical waveguide component design, when the light passes through the pupil expansion grating, some of the light will not be modulated by the pupil expansion grating (or the 0th order diffraction of the pupil expansion grating). At this time, the light will continue to propagate in the original direction until it is wasted at the edge of the optical waveguide component. This results in low optical efficiency of the existing optical waveguide solution.

[0048] In the light guide device provided in the embodiment of the present application, see Figure 1 and Figure 3 For a coupling-in grating on either side, it is equivalent to equipping it with two auxiliary pupil expansion gratings, one is a pupil expansion grating close to it, and the other is a pupil expansion grating far away from it. At this time, for example, the pupil expansion grating close to it can perform pupil expansion and deflection on the light transmitted through the coupling-in grating, and then inject it into a nearby coupling-out grating for coupling out, and the light that was originally wasted can be modulated by the distant pupil expansion grating and then coupled out by another coupling-out grating. In this way, the light that was originally wasted can be utilized to perform appropriate light energy compensation for the imaging light of the human eye corresponding to the above-mentioned other coupling-out grating, which realizes the reuse of light energy, thereby improving the overall optical efficiency of the light-guiding device.

[0049] With respect to the technical solution of the present application, the imaging light of both the left eye and the right eye of the user can be compensated. Since the propagation path of the light path is the same, it will not be described again here.

[0050] It should be noted that when light is coupled out from the substrate 8 of the light-guiding device through the coupling-out region, usually, the energy of the light coupled out first is higher than that coupled out later. Therefore, at the position of the coupling-out region, the closer to the coupling-in region, the higher the energy is usually.

[0051] In the technical solution provided in the above-mentioned embodiment of the present application, two coupling gratings are designed to couple the imaging light of the left eye and the right eye respectively, wherein a part of the imaging light of the left eye can be used to compensate the imaging light of the right eye, and similarly, a part of the imaging light of the right eye can be used to compensate the imaging light of the left eye. In this way, when the same light guide device is used for binocular imaging, the imaging light of both eyes can be compensated, which can improve the optical uniformity of the light guide device.

[0052] According to the light-guiding device provided in the embodiment of the present application, which is a binocular-view waveguide element, the fusion and improvement of two pupil-expanding gratings in the binocular-view waveguide element enable the light coupled in through the coupling grating on either side to not only satisfy the imaging of the waveguide on this side, but also to supplement and enhance the imaging of the waveguide on the other side, thereby improving the optical efficiency of the light-guiding device and the image uniformity of the final imaging as a whole, thereby improving the imaging effect of the light-guiding device, which is beneficial to improving the visual experience of the user.

[0053] The two coupling gratings constitute the coupling part of the entire light-guiding device, and any one of the coupling gratings is responsible for coupling the light emitted by the corresponding optical machine into the substrate 8 and enabling the light to propagate by total internal reflection in the substrate 8.

[0054] The two outcoupling gratings constitute the outcoupling part of the entire light guide device, one of which is responsible for coupling the imaging display light into the left eye, and the other is responsible for coupling the imaging display light into the right eye. This forms a single waveguide device corresponding to the binocular design.

[0055] The pupil expansion area includes a third grating 3 and a fourth grating 4 that are adjacently arranged, and any coupling-in grating on both sides of the substrate 8 can form at least two optical propagation paths through the third grating 3 and the fourth grating 4, so that the light coupled into the same side can be simultaneously modulated to be coupled out through the coupling-out gratings on both sides, so as to realize the complementary function of binocular imaging light.

[0056] According to the optical architecture of the light-guiding device provided in the embodiment of the present application, the shapes of the two coupling gratings in the coupling region are not restricted and can be designed into any shape as needed to match optical machines of various shapes, so that the design of the coupling part can be very flexible.

[0057] Optionally, the coupling-in region and the coupling-out region may be located on the same surface of the light-guiding device, or may be separately arranged on two opposite surfaces of the light-guiding device, which is not limited in the present application.

[0058] In some examples of this application, see Figure 1 and Figure 3The light-guiding device further includes an energy recovery zone, and the energy recovery zone is disposed on the substrate 8 and adjacent to the pupil expansion zone. The energy recovery zone is configured to receive part of the light modulated by the pupil expansion zone and reflect the part of the light to the outcoupling zone for outcoupling.

[0059] According to the above example, an energy recovery zone is introduced on the substrate 8 of the light-guiding device, which can add a new optical propagation path for the light coupled into the grating on either side, and can eventually be coupled out from the outcoupling zone to increase the light energy coupled out of the outcoupling zone.

[0060] According to the above example, the energy recovery zone is set close to the pupil expansion zone, and the light passing through the pupil expansion zone can be modulated to propagate toward the energy recovery zone. The energy recovery zone can reflect the light from the pupil expansion zone to make the light propagate to the outcoupling zone.

[0061] It should be noted that, by setting an energy recovery zone on the substrate 8, the light energy that was originally wasted can be further coupled out through another newly added optical propagation path to the coupling grating on the other side of the substrate 8, thereby realizing energy recycling, thereby improving the optical efficiency and optical uniformity of the light-guiding device.

[0062] In some examples of the present application, the coupling-in grating and the coupling-out grating are one-dimensional gratings. The pupil expansion grating is a two-dimensional grating, or a combination of at least two one-dimensional gratings.

[0063] The light-guiding device provided in the embodiment of the present application has one-dimensional gratings as both the coupling-in grating and the coupling-out grating, which can avoid the defect of low efficiency of the two gratings themselves. In addition, the one-dimensional gratings are easy to produce and more flexible in design.

[0064] The pupil expansion grating on the light-guiding device provided in the embodiment of the present application can use a two-dimensional grating to achieve pupil expansion and deflection of light, and can also use the cooperation between one-dimensional gratings to achieve the pupil expansion effect.

[0065] In the present application, for the one-dimensional grating, one or more of a surface relief grating and a holographic volume grating can be used. The surface relief grating includes a rectangular grating, a blazed grating, a tilted grating, a step grating, a sinusoidal grating, etc. The holographic volume grating includes a photopolymer volume grating, a polymer dispersed liquid crystal volume grating, a liquid crystal volume grating, etc.

[0066] In the present application, for the two-dimensional grating, a surface relief grating may be used, and specific types include but are not limited to parallelogram gratings, prism gratings, and double prism gratings.

[0067] It should be noted that in order to obtain better optical performance, in the light-guiding device provided in the embodiment of the present application, the grating in each functional area can be zoned and designed based on parameters such as grating thickness, duty cycle, grating tilt angle, coating depth, coating material, volume grating Bragg tilt angle and refractive index of volume grating material.

[0068] In some examples of the present application, the energy recovery zone includes at least one seventh grating 7, and the seventh grating 7 is a one-dimensional grating.

[0069] That is to say, a one-dimensional grating may be used in the energy recovery zone.

[0070] Optionally, the seventh grating 7 is located at one side of the pupil expansion area and can be as follows: Figure 1 and Figure 3 The long strip shown in the figure can fully receive the light transmitted after being modulated by the pupil expansion area, and reflect all the light to the outcoupling area for outcoupling, so as to make full use of the light energy and improve the optical efficiency.

[0071] In some examples of this application, see Figure 1 and Figure 3 , the coupling-in area, the coupling-out area, the pupil expansion area and the energy recovery area are located on the same surface of the substrate 8;

[0072] The two coupling-in gratings are arranged on opposite sides of the pupil expansion area along a first direction R1, the two coupling-out gratings and the seventh grating 7 are arranged on opposite sides of the pupil expansion area along a second direction R2, and the two coupling-out gratings are located on the same side of the pupil expansion area, and the first direction R1 and the second direction R2 form a preset angle.

[0073] Optionally, the preset angle formed by the first direction R1 and the second direction R2 is 90°

[0074] Specifically, the two coupling gratings in the coupling zone are arranged along the length direction of the substrate 8, and the two are located on the left and right sides of the pupil expansion zone; the energy recovery zone and the coupling zone are arranged along the width direction of the substrate 8, and the two are arranged on the upper and lower sides of the pupil expansion zone, see Figure 1 and Figure 3 The two pupil expansion gratings included in the pupil expansion area are arranged close to each other, and other grating areas are arranged around the two pupil expansion grating areas.

[0075] In some examples of this application, see Figure 1The two coupling-in gratings include a first grating 1 and a second grating 2 arranged at intervals. The two pupil expansion gratings include a third grating 3 and a fourth grating 4 arranged adjacent to each other. The two coupling-out gratings include a fifth grating 5 and a sixth grating 6 arranged at intervals. The seventh grating 7 is arranged on the side of the two pupil expansion gratings away from the two coupling-out regions.

[0076] After the first light ray 01 is coupled in by the first grating 1: a part of the first light ray 01 is propagated to the fifth grating 5 for out-coupling after the pupil expansion and turning of the third grating 3; another part of the first light ray 01 is propagated to the fourth grating 4, and is propagated to the sixth grating 6 for out-coupling after the pupil expansion and turning of the fourth grating 4; and another part of the first light ray 01 is modulated by the third grating 3 and then turned to propagate to the seventh grating 7, and is reflected by the seventh grating 7 to the sixth grating 6 for out-coupling.

[0077] To facilitate the explanation of the modulation effect of the gratings in each functional area of ​​the light guide device of the present application on the light, see Figure 2 and Figure 4 , respectively K i，m or K ij，m Indicates the control capability of a certain diffraction order of the grating in each functional area. Figure 1 and Figure 3 The code of the grating shown in the figure; the subscript j represents the serial number of the diffraction direction of the functional area with multiple diffraction directions; the subscript m represents the diffraction order of the grating, and only 1 and -1 are designed in this application. For example, K 42，1 Represents the first-order diffraction vector of the second diffraction direction of the fourth grating.

[0078] On this basis, for the above example, see Figure 1 and Figure 2 , the first light 01 is emitted through the corresponding optical machine (for example, the first optical machine corresponding to the left eye) and projected onto the coupling grating. Taking the first grating 1 on the left side (located on the left eye side) as an example, the first light 01 coupled into the substrate 8 is totally reflected and propagated, and then coupled out through the following three optical propagation paths respectively:

[0079] Optical propagation path 1: K 1，1 +K 31，1 +K 5，1 That is, after the first light 01 is coupled in through the first grating 1 , it is expanded and turned through the third grating 3 , and finally coupled out through the fifth grating 5 .

[0080] Optical propagation path 2: K 1，1 +K 42，1 +K 6，1That is, after the first light 01 is coupled in through the first grating 1 , it is expanded and turned through the fourth grating 4 , and finally coupled out through the sixth grating 6 .

[0081] Optical propagation path 3: K 1，1 +K 32，-1 +K 7，1 +K 6，1 That is, after the first light 01 is coupled into the first grating 1, a part of the first light 01 is affected by K when passing through the third grating 3. 32，-1 The modulation propagates upward, is turned back after encountering the additionally arranged seventh grating 7, and is finally coupled out through the sixth grating 6.

[0082] The optical propagation path 1 is the main propagation path of the light, and the optical propagation path 2 and the optical propagation path 3 are secondary propagation paths. This design has the following advantages:

[0083] First, the wasted light energy can be coupled out through the above-mentioned optical propagation path 2 and optical propagation path 3 at the coupling grating position on the right eye side to compensate for the imaging light of the right eye, thereby realizing the reuse of light energy and improving the overall optical efficiency of the light guide device.

[0084] Second, the light from the above-mentioned optical propagation path 2 and optical propagation path 3 is incident on the out-coupling grating on the right eye side, and at the same time, the optical propagation path 1 on the right eye side is also incident on the out-coupling grating on the right eye side. The fusion of the three light rays at the same out-coupling grating can play a compensation role and improve the optical uniformity of the light-guiding device.

[0085] In some examples of this application, see Figure 3 After the second light 02 is coupled in by the second grating 2: a part of the second light 02 is propagated to the sixth grating 6 for coupling out after the pupil expansion and turning of the fourth grating 4; another part of the second light 02 is propagated to the third grating 3, and is propagated to the fifth grating 5 for coupling out after the pupil expansion and turning of the third grating 3; and another part of the second light 02 is modulated by the fourth grating 4 and then turned to propagate to the seventh grating 7, and is reflected by the seventh grating 7 to the fifth grating 5 for coupling out.

[0086] According to the above example, the propagation path of the second light 02 coupled by the coupling grating located on the right side (ie, the right eye side) of the light guide device is described.

[0087] Specifically, first, the second light 02 is emitted through the corresponding optical machine (for example, the second optical machine corresponding to the right eye) and projected onto the coupling grating on the right side. Figure 3The second grating 2 shown in the figure is coupled into the second light 02 in the substrate 8 for total reflection propagation, and then coupled out through the following three optical propagation paths respectively:

[0088] Optical propagation path 1: K 2，1 +K 41，1 +K 6，1 That is, the second light 02 is coupled in through the second grating 2, then passes through the fourth grating 4 for pupil expansion and turning, and finally is coupled out through the sixth grating 6. This optical propagation path is the main propagation route of the light.

[0089] Optical propagation path 2: K 2，1 +K 32，1 +K 5，1 That is, the second light 02 is coupled in through the second grating 2, then passes through the third grating 3 to expand the pupil and turn, and finally is coupled out through the fifth grating 5. This optical propagation path is a secondary propagation route of the light.

[0090] Optical propagation path 3: K 2，1 +K 42，-1 +K 7，1 +K 5，1 That is, after the second light 02 is coupled into the second grating 2, when passing through the fourth grating 4, part of the second light 02 is affected by K 42，-1 The modulated light propagates upward, is turned back after encountering the additionally provided seventh grating 7, and is finally coupled out through the fifth grating 5. This optical propagation path is also a secondary propagation route of the light.

[0091] According to the above two examples, the optical propagation paths 1 to 3 on both sides of the light guide device are performed simultaneously, so that a single light guide device can correspond to binocular imaging.

[0092] Among them, see Figure 1 , the fifth grating 5 corresponding to the left eye can receive the first light 01 brought by the optical propagation path 1 on the left eye side, and the second light 02 brought by the optical propagation path 2 and the optical propagation path 3 on the right eye side. At this time, the second light 02 can compensate for the first light 01 incident on the left eye. Similarly, see Figure 3 The sixth grating 6 corresponding to the right eye can receive the second light 02 brought by the optical propagation path 1 on the right eye side, as well as the second light 02 brought by the optical propagation path 2 and the optical propagation path 3 on the left eye side. At this time, the first light 01 can compensate for the second light 02 incident on the right eye.

[0093] In some examples of the present application, the third grating 3 includes at least a first diffraction direction and a second diffraction direction, the first diffraction direction is used to deflect the first light 01 coupled into the third grating 3 through the first grating 1 to the fifth grating 5, and the second diffraction direction is used to deflect the second light 02 coupled into the third grating 3 through the second grating 2 to the fifth grating 5. The fourth grating 4 is the same as the third grating 3.

[0094] According to the above example, the third grating 3 and the fourth grating 4 are both pupil expansion gratings, and both may have two grating vector directions, which may form two diffraction directions such as the first diffraction direction and the second diffraction direction mentioned above.

[0095] In the above example, two diffraction directions are described by taking the third grating 3 as an example, and the second diffraction direction of the third grating 3 is the turning direction of the optical propagation path 2 on the other side.

[0096] Based on the above example, see Figure 3 and Figure 4 The fourth grating 4 also includes a first diffraction direction and a second diffraction direction. The first diffraction direction is used to make the second light ray 02 coupled into and propagated to the fourth grating 4 through the second grating 2 bend to the sixth grating 6. The second diffraction direction is used to make the first light ray 01 coupled into and propagated to the fourth grating 4 through the first grating 1 bend to the sixth grating 6.

[0097] In some examples of this application, see Figure 1 and Figure 2 , the sum of the vectors of the first grating 1, the third grating 3 and the fifth grating 5 is zero, the sum of the vectors of the first grating 1, the fourth grating 4 and the sixth grating 6 is zero, and the sum of the vectors of the first grating 1, the third grating 3, the seventh grating 7 and the sixth grating 6 is zero.

[0098] According to the above example, each grating in the above three optical propagation paths satisfies the vector closure condition, that is, the sum of its grating vectors is zero.

[0099] In some examples of this application, see Figure 3 and Figure 4 , the sum of the vectors of the second grating 2, the fourth grating 4 and the sixth grating 6 is zero, the sum of the vectors of the second grating 2, the third grating 3 and the fifth grating 5 is zero, and the sum of the vectors of the second grating 2, the fourth grating 4, the seventh grating 7 and the fifth grating 5 is zero.

[0100] According to the above example, each grating in the above three optical propagation paths satisfies the vector closure condition, that is, the sum of its grating vectors is zero.

[0101] In some examples of the present application, a nose avoidance area 9 is provided on the substrate 8, the pupil expansion area is located on one side of the nose avoidance area 9, the two coupling-in gratings are symmetrically arranged on opposite sides of the pupil expansion area and away from the nose avoidance area 9, and the two coupling-out gratings are arranged on opposite sides of the nose avoidance area 9 and correspond to the left eye and the right eye respectively, so as to form an optical structure in which a single light guide device corresponds to two eyes.

[0102] In some examples of the present application, the light guiding device is a diffractive light waveguide.

[0103] According to another embodiment of the present application, a head mounted display device is provided, which includes a housing, two optical engines, and the light guide device described above, wherein the two optical engines and the two coupling gratings of the light guide device are arranged in a one-to-one correspondence.

[0104] The head mounted display device includes AR smart glasses or AR smart helmets, etc., which is not limited in the embodiments of the present application.

[0105] The specific implementation of the head-mounted display device of the embodiment of the present application can refer to the above-mentioned embodiments of the light guide device, 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.

[0106] 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.

[0107] 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 light guide device, characterized in that: It comprises a substrate (8) and an in-coupling region, an out-coupling region and a pupil expansion region arranged on the substrate (8), wherein the in-coupling region comprises two in-coupling gratings, the out-coupling region comprises two out-coupling gratings, and the pupil expansion region comprises two pupil expansion gratings; The pupil expansion area is located between the optical paths of the coupling-in area and the coupling-out area, and the light coupled in from any of the coupling-in gratings can be coupled out from the two coupling-out gratings after being modulated by the two pupil expansion gratings, and the two coupling-out gratings correspond to the left eye and the right eye respectively.

2. The light guide device according to claim 1, characterized in that: The light-guiding device also includes an energy recovery zone, and the energy recovery zone is arranged on the substrate and adjacent to the pupil expansion zone. The energy recovery zone is configured to receive part of the light modulated by the pupil expansion zone and reflect the part of the light to the outcoupling zone for outcoupling.

3. The light guide device according to claim 2, characterized in that: The coupling-in grating and the coupling-out grating are one-dimensional gratings; The pupil expansion grating is a two-dimensional grating, or a combination of at least two one-dimensional gratings.

4. The light guide device according to claim 2 or 3, characterized in that: The energy recovery zone comprises at least one seventh grating (7), and the seventh grating (7) is a one-dimensional grating.

5. The light guide device according to claim 4, characterized in that: The coupling-in area, the coupling-out area, the pupil expansion area and the energy recovery area are located on the same surface of the substrate (8); The two coupling-in gratings are arranged on opposite sides of the pupil expansion area along a first direction R1, the two coupling-out gratings and the seventh grating (7) are arranged on opposite sides of the pupil expansion area along a second direction R2, and the two coupling-out gratings are located on the same side of the pupil expansion area, and the first direction R1 and the second direction R2 form a preset angle.

6. The light guide device according to claim 5, characterized in that: The two coupling-in gratings include a first grating (1) and a second grating (2) arranged at intervals, the two pupil expansion gratings include a third grating (3) and a fourth grating (4) arranged adjacent to each other, the two coupling-out gratings include a fifth grating (5) and a sixth grating (6) arranged at intervals, and the seventh grating (7) is arranged on a side of the two pupil expansion gratings away from the two coupling-out regions; After the first light ray (01) is coupled in through the first grating (1), a portion of the first light ray (01) is propagated to the fifth grating (5) after being dilated and turned through the third grating (3) for out-coupling; another portion of the first light ray (01) is propagated to the fourth grating (4), and is propagated to the sixth grating (6) after being dilated and turned through the fourth grating (4) for out-coupling; and another portion of the first light ray (01) is modulated through the third grating (3) and turned to propagate to the seventh grating (7), and is reflected from the seventh grating (7) to the sixth grating (6) for out-coupling.

7. The light guide device according to claim 6, characterized in that: After the second light ray (02) is coupled in through the second grating (2), a portion of the second light ray (02) is propagated to the sixth grating (6) for out-coupling after being dilated and turned through the fourth grating (4); another portion of the second light ray (02) is propagated to the third grating (3), and is propagated to the fifth grating (5) for out-coupling after being dilated and turned through the third grating (3); and another portion of the second light ray (02) is modulated by the fourth grating (4) and turned to propagate to the seventh grating (7), and is reflected by the seventh grating (7) to the fifth grating (5) for out-coupling.

8. The light guide device according to claim 7, characterized in that: The third grating (3) comprises at least a first diffraction direction and a second diffraction direction, the first diffraction direction being used to deflect a first light ray (01) coupled into the third grating (3) through the first grating (1) to the fifth grating (5), and the second diffraction direction being used to deflect a second light ray (01) coupled into the third grating (3) through the second grating (2) to the fifth grating (5); The fourth grating (4) is the same as the third grating (3).

9. The light guide device according to claim 6, characterized in that: The sum of the vectors of the first grating (1), the third grating (3) and the fifth grating (5) is zero, the sum of the vectors of the first grating (1), the fourth grating (4) and the sixth grating (6) is zero, and the sum of the vectors of the first grating (1), the third grating (3), the seventh grating (7) and the sixth grating (6) is zero.

10. The light guide device according to claim 7 or 9, characterized in that: The sum of the vectors of the second grating (2), the fourth grating (4) and the sixth grating (6) is zero, the sum of the vectors of the second grating (2), the third grating (3) and the fifth grating (5) is zero, and the sum of the vectors of the second grating (2), the fourth grating (4), the seventh grating (7) and the fifth grating (5) is zero.

11. The light guide device according to claim 1, characterized in that: A nose bridge avoidance area (9) is arranged on the substrate (8), the pupil expansion area is located on one side of the nose bridge avoidance area (9), the two coupling-in gratings are symmetrically arranged on opposite sides of the pupil expansion area and away from the nose bridge avoidance area (9), and the two coupling-out gratings are arranged on opposite sides of the nose bridge avoidance area (9) and correspond to the left eye and the right eye respectively, so as to form an optical structure in which a single light guide device corresponds to both eyes.

12. The light guide device according to claim 1, characterized in that: The light guiding device is a diffraction light waveguide.

13. A head mounted display device, characterized in that: include: shell; Two optical machines; as well as, The light guide device according to any one of claims 1 to 12; The two optical machines are arranged in a one-to-one correspondence with the two coupling-in gratings of the light-guiding device.

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