Optical modules, display control methods, and head-mounted display devices

Abstract

This application provides an optical module, a display control method, and a head-mounted display device. The optical module includes an optical engine and a light guide device. The optical engine emits light rays at different virtual image distances so that the virtual image of the optical module can be displayed at multiple virtual image distances, with each type of light ray corresponding to a virtual image distance position. The light guide device includes a transparent substrate and a coupling-in region and a coupling-out region disposed on the transparent substrate. The coupling-in region couples in light rays at different virtual image distance positions and causes the coupled light rays to propagate to the coupling-out region via total internal reflection within the transparent substrate. The coupling-out region couples out light rays propagating to the coupling-out region. The coupling-out region includes multiple coupling-out gratings arranged in an array. The multiple coupling-out gratings include at least two different grating structures. Each grating structure coupler couples couple out light rays at a virtual image distance position corresponding to that coupler coupler. Coupler couplers with the same grating structure couple out light rays at the same virtual image distance position.

Description

Technical Field

[0001] This application relates to the field of optical imaging technology, and more specifically, to an optical module, a display control method, and a head-mounted display device. Background Technology

[0002] The virtual image distance adjustment function of AR products has always been a problem that has plagued AR manufacturers. AR products that cannot adjust the virtual image distance will have their use cases greatly limited, and the wearing experience for users will also be greatly reduced due to convergence adjustment conflicts.

[0003] Currently, AR products mainly include optical solutions such as freeform surfaces, Birdbath, arrayed waveguides, and diffractive waveguides. Among these, only the Birdbath optical solution can adjust the virtual image distance by adjusting the distance between the screen and the Birdbath mirror. The other optical solutions do not have a mature virtual image distance adjustment solution like Birdbath, and the AR market urgently needs to fill this gap. Summary of the Invention

[0004] The purpose of this application is to provide a new technical solution for an optical module, a display control method, and a head-mounted display device.

[0005] In a first aspect, this application provides an optical module. The optical module includes:

[0006] An optical engine is used to emit light rays at different virtual image distance positions so that the virtual image of the optical module can be presented at multiple virtual image distance positions, and each type of light ray corresponds to a virtual image distance position.

[0007] A light guiding device includes a transparent substrate and a coupling-in region and a coupling-out region disposed on the transparent substrate;

[0008] The coupling region is configured to couple in light rays at the different virtual image distance positions, and to allow the coupled light rays to propagate through total internal reflection within the transparent substrate to the coupling region.

[0009] The coupling region is used to couple out light rays propagating to the coupling region. The coupling region includes a plurality of coupling gratings arranged in an array. The plurality of coupling gratings include at least two different grating structures, and each grating structure is used to couple out light rays at a virtual image distance position corresponding to that grating. Within the coupling region, coupling gratings with the same grating structure are used to couple out light rays at the same virtual image distance position.

[0010] Optionally, the coupling region includes multiple coupling gratings with different grating structures, and all the coupling gratings are located on the same surface of the transparent substrate and form partitions within the coupling region, with each coupling grating being opposite to the optomechanical system;

[0011] The number of coupling gratings n1 in the coupling region and the number of adjustable virtual image distance positions n2 of the optical module satisfy n1 = n2, and both n1 and n2 are greater than or equal to 2, so that the optical module can achieve adjustment of at least two virtual image distance positions.

[0012] Optionally, each of the coupling gratings is configured to couple in light rays at a virtual image distance position corresponding to its own grating structure, and each of the coupling gratings has at least one corresponding coupling grating in the coupling region.

[0013] Optionally, when the optical module has three adjustable virtual image distance positions, the coupling region includes a first coupling grating, a second coupling grating, and a third coupling grating, and the first coupling grating, the second coupling grating, and the third coupling grating are respectively used to couple out light rays at three different virtual image distance positions;

[0014] The first coupling grating, the second coupling grating, and the third coupling grating are each configured as at least one.

[0015] Optionally, the coupling region includes a first coupling grating, a second coupling grating, and a third coupling grating;

[0016] The first coupling grating is used to couple in light rays corresponding to the first target virtual image distance position and make the coupled light rays propagate through total internal reflection within the transparent substrate to the coupling out region, and then couple out through the first coupling out grating corresponding to the first coupling grating;

[0017] The second coupling grating is used to couple in light rays corresponding to the second target virtual image distance position and cause the coupled light rays to propagate through total internal reflection within the transparent substrate to the coupling out region, and then couple out through the second coupling out grating corresponding to the second coupling grating;

[0018] The third coupling grating is used to couple in light rays corresponding to the third target virtual image distance position and make the coupled light rays propagate through total internal reflection within the transparent substrate to the coupling region, and then couple out through the third coupling grating corresponding to the third coupling grating.

[0019] Optionally, the optical engine includes a light source and an optical engine lens, and the distance between the light source and the optical engine lens is set to be adjustable to emit light at different virtual image distance positions; wherein, the distance between the light source and the optical engine lens is set in a one-to-one correspondence with the virtual image distance positions.

[0020] Optionally, the optical engine is a display optical engine, and the emitted light carries image information;

[0021] The light emitted by the optical engine can cover the coupling region; or,

[0022] The optomechanism is configured to move relative to the coupling region;

[0023] The relative position between the light source and the optomechanical lens can be varied to project corresponding light rays onto the target coupling grating within the coupling region.

[0024] Optionally, the coupling-in region and the coupling-out region are disposed on the same surface of the transparent substrate at intervals, or are disposed on two opposite surfaces of the transparent substrate.

[0025] Optionally, the light guiding device is a diffractive waveguide device.

[0026] Optionally, by adjusting the grating parameters of the coupling grating and the coupling grating, at least two different coupling gratings can be formed in the coupling region, at least two different coupling gratings can be formed in the coupling region, and each coupling grating has at least one corresponding coupling grating in the coupling region; wherein, the grating parameters include at least one of grating period, duty cycle, slot depth and sidewall tilt angle.

[0027] Secondly, this application provides a display control method for an optical module, the display control method comprising:

[0028] Obtain the target virtual image distance position;

[0029] Based on the target virtual image distance position, the optomechanic is controlled to emit corresponding light rays, which are then projected onto the coupling area on the transparent substrate.

[0030] The light rays are coupled into the transparent substrate through the coupling region, and then propagate through total internal reflection in the transparent substrate to the coupling region. The light rays are then emitted through at least one target coupling grating in the coupling region, and the resulting virtual image is presented at the target virtual image position.

[0031] Thirdly, this application provides an electronic device. The electronic device includes:

[0032] Casing; and

[0033] The optical module as described in the first aspect.

[0034] Optionally, the head-mounted display device is smart glasses or a smart helmet, which includes:

[0035] A front frame assembly, wherein a left lens mounting portion and a right lens mounting portion are provided on the front frame assembly, and a bridge portion is provided between the left lens mounting portion and the right lens mounting portion;

[0036] The optical module is configured as two:

[0037] One of the optical modules has a transparent substrate disposed within the left lens mounting portion, and the optical mechanism of the optical module is disposed at the end of the left lens mounting portion away from the bridge of the nose and opposite to the coupling area on the transparent substrate, and the coupling area on the transparent substrate is opposite to the user's left eye.

[0038] Another optical module has a transparent substrate disposed within the right lens mounting portion, and the optical engine of the optical module is disposed at the end of the right lens mounting portion away from the bridge of the nose and opposite to the coupling area on the transparent substrate, and the coupling area on the transparent substrate is opposite to the user's right eye.

[0039] Optionally, the head-mounted display device further includes a head-mounted wearing component and a frame-type wearing component, wherein the head-mounted wearing component and the frame-type wearing component are detachably connected to the front frame component.

[0040] The beneficial effects of this application are as follows:

[0041] According to the optical module provided in the embodiments of this application, it is an optical solution with adjustable virtual image distance. The coupling area on the transparent substrate is designed to include multiple independent coupling gratings, which can be used to couple out light rays at different virtual image distance positions. Thus, according to the target virtual image distance position, the corresponding light rays can be coupled into the coupling area, and the coupled light rays can be propagated to the coupling area by total internal reflection within the transparent substrate. The coupling area has a corresponding coupling grating that can change the deflection angle of the light rays before they are emitted. The entire solution realizes the virtual image distance adjustment function of the optical module. The optical module provided in the embodiments of this application enables the optical module to have the virtual image distance adjustment function.

[0042] Other features and advantages of this specification will become clear from the following detailed description of exemplary embodiments with reference to the accompanying drawings. Attached Figure Description

[0043] The accompanying drawings, which are incorporated in and form part of this specification, illustrate embodiments of this specification and, together with their description, serve to explain the principles of this specification.

[0044] Figure 1 This is a schematic diagram of the structure of the optical module provided in the embodiments of this application;

[0045] Figure 2 This is a schematic diagram of the optical module in the coupling region provided in the embodiments of this application;

[0046] Figure 3 A schematic diagram of the coupling region of the light guide device provided in an embodiment of this application;

[0047] Figure 4 A flowchart of the display control method for the optical module provided in the embodiments of this application.

[0048] Explanation of reference numerals in the attached figures:

[0049] 1. Optical engine; 2. Transparent substrate; 3. Coupled-in region; 31. First coupling-in grating; 32. Second coupling-in grating; 33. Third coupling-in grating; 4. Coupled-out region; 41. First coupled-out grating; 42. Second coupled-out grating; 43. Third coupled-out grating. Detailed Implementation

[0050] 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, numerical expressions, and values ​​of the components and steps set forth in these embodiments do not limit the scope of the present application.

[0051] The following description of at least one exemplary embodiment is merely illustrative and is in no way intended to limit the scope of this application and its application or use.

[0052] Technologies and equipment known to those skilled in the art may not be discussed in detail, but where appropriate, such technologies and equipment should be considered part of the specification.

[0053] In all the examples shown and discussed herein, any specific values ​​should be interpreted as merely exemplary and not as limitations. Therefore, other examples of exemplary embodiments may have different values.

[0054] It should be noted that similar labels and letters in the following figures indicate similar items; therefore, once an item is defined in one figure, it does not need to be discussed further in subsequent figures.

[0055] The following is in conjunction with the appendix Figures 1 to 4 The present application provides a detailed description of the optical module, display control method, and head-mounted display device for electronic devices.

[0056] According to one aspect of the embodiments of this application, an optical module is provided, which is suitable for application in wearable devices. The wearable device is, for example, a head-mounted display (HMD), such as an AR head-mounted display. Furthermore, the specific form of the head-mounted display device may be, for example, smart glasses or a smart helmet, etc., and the embodiments of this application do not limit the specific form of the head-mounted display device.

[0057] According to one embodiment of this application, an optical module is provided, see [link to relevant documentation]. Figure 1 and Figure 2 The optical module includes an optomechanical system 1 and a light guide device. The optomechanical system 1 emits light rays at different virtual image distances (VAPs) to allow the virtual image of the optical module to be displayed at multiple VAPs, with each type of light ray corresponding to a specific VAP. The light guide device includes a transparent substrate 2 and coupling-in and coupling-out regions 4 disposed on the transparent substrate 2. The coupling-in region 3 is configured to couple in light rays at the different VAPs and allow the coupled light rays to propagate through total internal reflection within the transparent substrate 2 to the coupling-out region 4. The coupling-out region 4 is used to couple out the light rays propagating to it. The coupling-out region 4 includes multiple coupling-out gratings arranged in an array. These multiple coupling-out gratings include at least two different grating structures, and each grating structure is used to couple out light rays at a specific VAP corresponding to that grating. Within the coupling-out region 4, coupling-out gratings with the same grating structure are used to couple out light rays at the same VAP.

[0058] In this context, the distance between the user's eye and the virtual image formed by the optical module when using the optical module is called the virtual image distance. The optical module provided in this application embodiment can achieve adjustment of the virtual image position.

[0059] According to the embodiments described above in this application, the optical module mainly consists of an optical engine 1 and a light guide device. The optical engine 1, for example, is a display optical engine, which can emit light carrying image information. The light guide device, as a light transmission device, can transmit the light emitted by the optical engine 1 and couple the light out to form an image in, for example, the human eye. The image is a virtual image formed after the imaging light passes through the optical module.

[0060] The entire optical module has a simple structural design, requiring no major modifications to its structure. This optical module can be applied to applications such as AR products. The light guide device, for example, is a diffractive waveguide, which enables virtual image distance adjustment. Of course, the light guide device can also be other forms of diffractive optical elements, not limited to diffractive waveguides.

[0061] It should be emphasized that the optical solution provided in this application embodiment realizes an optical adjustment method for the virtual image distance position, and does not involve software adjustment of the virtual image distance. Compared with software adjustment of the virtual image distance, it is simpler and lower in cost.

[0062] According to the above embodiments of this application, the optical module includes a light guide device, the light guide device includes a transparent substrate 2, and a coupling-in region 3 and a coupling-out region 4 are respectively provided on the transparent substrate 2; wherein, the coupling-out region 4 has multiple sub-regions, and a coupling-out grating is provided in each sub-region, thus forming a grating partition design in the coupling-out region 4.

[0063] Among the multiple coupling gratings in the coupling region 4, there can be coupling gratings with the same grating structure or coupling gratings with different grating structures. Coupling gratings with different grating structures can couple light rays from different virtual image distance positions, while coupling gratings with the same grating structure can control the coupling of light rays from the same virtual image distance position.

[0064] In this application, at least two different grating structures are provided in the coupling region 4, which can be used to couple out light rays at at least two different virtual image distance positions. Each type of grating structure can couple out light rays corresponding to one virtual image distance position, and they do not interfere with each other.

[0065] According to the optical module provided in this application embodiment, a light guide device is used to transmit the light emitted by the optomechanical system 1. The optomechanical system 1 can emit light at different virtual image distance positions, and the coupling region 3 can couple in light at different virtual image distance positions, causing the coupled light to propagate through total internal reflection within the transparent substrate 2 to the coupling region 4. Then, through different coupling gratings within the coupling region 4, light at different virtual image distance positions can be coupled out and imaged, thereby allowing the virtual image to be presented at different virtual image distance positions. The entire optical module has an adjustable virtual image distance function.

[0066] According to the optical module provided in the above embodiments of this application, light rays coupled to different virtual image distance positions within the coupling region 3 can be designed to be emitted from the same optical engine 1. See [link to relevant documentation]. Figure 1 In other words, the optical engine 1 can emit light rays that form different virtual image distances. In this way, there is no need to increase the number of optical engines, and there is no increase in cost or the size and weight of the entire optical module.

[0067] Traditional diffractive waveguide devices cannot adjust the distance of the virtual image they form. However, the optical module provided in this application embodiment has a virtual image distance adjustment function.

[0068] According to the optical module provided in the embodiments of this application, it is an optical solution with adjustable virtual image distance. The coupling region 3 on the transparent substrate 2 is designed to include multiple independent coupling gratings, which can be used to couple out light rays at different virtual image distance positions. Thus, according to the target virtual image distance position, the corresponding light rays can be coupled into the coupling region, and the coupled light rays can be propagated to the coupling region 4 by total internal reflection within the transparent substrate 2. The coupling region 4 has a corresponding coupling grating that can change the deflection angle of the light rays before they are emitted. The entire solution realizes the virtual image distance adjustment function of the optical module.

[0069] The optical module provided in this application embodiment enables the optical module to have a virtual image distance adjustment function without affecting the overall optical scheme, thereby further improving and enriching the application scenarios of the optical module and making the optical display effect more realistic.

[0070] See some examples in this application. Figure 3 The coupling region 3 includes multiple coupling gratings with different grating structures, and all the coupling gratings are located on the same surface of the transparent substrate 2 and form partitions within the coupling region 3. Each coupling grating is opposite to the optomechanical system 1. The number of coupling gratings n1 within the coupling region 3 and the number of adjustable virtual image distance positions n2 of the optical module satisfy n1 = n2, and both n1 and n2 are greater than or equal to 2, so that the optical module can achieve adjustment of at least two virtual image distance positions.

[0071] For example, see Figure 3 The coupling region 3 includes three coupling gratings with different grating parameters, namely... Figure 3 The first coupling grating 31, the second coupling grating 32, and the third coupling grating 33 shown in the figure have different grating parameters, corresponding to D1, D2, and D3 respectively. The three coupling gratings are arranged to form the coupling region 3 and are located on the same surface of the transparent substrate 2 and are spaced apart from each other to form a partitioned design. In this way, they will not interfere with each other when different light rays are coupled in.

[0072] It should be noted that the coupling region 3 includes, but is not limited to, setting three different coupling gratings, and the number of coupling gratings can be designed according to actual needs.

[0073] For example, the number of coupling gratings in the coupling region 3 can be set to 2 to 20.

[0074] Preferably, the number of coupling gratings in the coupling region 3 is less than 15.

[0075] If too many coupling gratings are set in a coupling region, such as more than 20, the size of each coupling grating will be too small due to the limited size of the coupling region itself, which will affect the imaging.

[0076] The coupling region 3 can be designed to be opposite to the optical engine 1 so that the light emitted from the optical engine 1 can be smoothly projected into the coupling region 3, thereby improving the coupling efficiency.

[0077] In order for the user's eyes to see the virtual image formed by the optical module, the coupling region 4 on the light guide device should be opposite to the user's eyes. For example, the center of the coupling region 4 should be able to fall on the visual axis of the user's eyes.

[0078] According to the example above in this application, within the coupling region 3, the number of coupling gratings should match the number of adjustable virtual image distance positions of the optical module, that is, satisfy the relationship n1 = n2 in the example above; and the design that the values ​​of n1 and n2 are both ≥ 2 is to take into account that if the virtual image distance is adjusted, there should be at least two different virtual image distance positions.

[0079] According to the light guide device provided in the embodiments of this application, the division of different blocks of the coupling-in region 3 and / or the coupling-out region 4 depends on the number of virtual image distance positions that the optical module needs to adjust and the ability of the optical engine 1 to display virtual image distance images at different positions at the initial design.

[0080] In some examples of this application, any of the coupled-in gratings is configured to couple in light rays at a virtual image distance position corresponding to its own grating structure, and any of the coupled-in gratings has at least one coupled-out grating corresponding to it in the coupled-out region 4.

[0081] For light rays corresponding to different virtual image distances emitted from the optomechanical 1 to enter the human eye via the incident grating and exit grating, a specific correspondence between the incident grating and the exit grating must be satisfied. This specific correspondence means that there is a unique correspondence between the grating parameters such as the grating period, duty cycle, slot depth, and sidewall tilt angle of the incident grating and the exit grating. The grating can only function normally if this correspondence is satisfied, but it does not mean that the grating parameters such as the grating period, duty cycle, slot depth, and sidewall tilt angle of the incident grating and the exit grating are exactly the same everywhere.

[0082] See some examples in this application. Figure 1 and Figure 2 When the optical module has three adjustable virtual image distance positions, the coupling region 4 includes a first coupling grating 41, a second coupling grating 42, and a third coupling grating 43, and the first coupling grating 41, the second coupling grating 42, and the third coupling grating 43 are respectively used to couple out light rays at three different virtual image distance positions; wherein, the first coupling grating 41, the second coupling grating 42, and the third coupling grating 43 are respectively set to at least one.

[0083] According to the above example, within the coupling region 4, the coupling gratings with the same grating parameters are not limited to only one. That is, the first coupling grating 41, the second coupling grating 42, and the third coupling grating 43 can each be configured as multiple. Rays at the same virtual image distance position are coupled out through multiple identical coupling gratings.

[0084] Based on the example above, see Figure 3 The coupling region 3 includes a first coupling grating 31, a second coupling grating 32, and a third coupling grating 33. The first coupling grating 31 is used to couple in light rays corresponding to a first target virtual image distance position and cause the coupled light rays to propagate through total internal reflection within the transparent substrate 2 to the coupling region 4, and then couple out through the first coupling grating 41 corresponding to the first coupling grating 31. The second coupling grating 32 is used to couple in light rays corresponding to a second target virtual image distance position and cause the coupled light rays to propagate through total internal reflection within the transparent substrate 2 to the coupling region 4, and then couple out through the second coupling grating 42 corresponding to the second coupling grating 32. The third coupling grating 33 is used to couple in light rays corresponding to a third target virtual image distance position and cause the coupled light rays to propagate through total internal reflection within the transparent substrate 2 to the coupling region 4, and then couple out through the third coupling grating 43 corresponding to the third coupling grating 33.

[0085] Specifically, the coupling region 3 is composed of, for example, three coupling gratings with different grating structures: a first coupling grating 31, a second coupling grating 32, and a third coupling grating 33. (See [reference]). Figure 3 The three coupling gratings with different grating structures have different grating parameters, which can be defined as D1, D2, and D3, respectively. Each grating structure can be coupled into a ray at a virtual image distance position.

[0086] The light coupled into the coupling region 3 undergoes total internal reflection in the transparent substrate 2, and the position of the coupling region 4 is changed by the corresponding coupling grating to change the deflection angle of the light before it enters the human eye.

[0087] Specifically, see Figure 2 The coupling region 4 includes multiple coupling gratings, and these coupling gratings include three different grating structures, namely... Figure 2 The first coupling grating 41, the second coupling grating 42, and the third coupling grating 44 shown are illustrated. The grating parameters corresponding to these three coupling gratings with different structures can be represented by A1, A2, and A3, respectively. Due to the characteristics of diffraction gratings, each coupling grating with a specific structure only deflects light rays incident on the grating at a specific angle, while not altering the propagation path of other light rays that cannot be affected by the grating. Thus, when totally internally reflected light rays in the light guide device 2 illuminate the coupling region 4, the light rays may be coupled out only after being acted upon by the corresponding coupling grating.

[0088] For example, the correspondence between grating parameters such as grating period, duty cycle, slot depth, and sidewall tilt angle for input and output gratings: See [link to relevant documentation]. Figure 2 and Figure 3 The grating parameters of the first coupling grating 31 are designed as D1, and the grating parameters of the first coupling grating 41 are designed as A1. When D1 = A1, it indicates that the first coupling grating 31 and the first coupling grating 41 have a corresponding relationship. Thus, light coupled into the transparent substrate 2 through the first coupling grating 31 can be totally internally reflected to the coupling region 4 and coupled out through the first coupling grating 41. Similarly, the grating parameters of the second coupling grating 32 are designed as D2, and the grating parameters of the second coupling grating 42 are designed as A2. When D2 = A2, it indicates that the second coupling grating 32 and the second coupling grating 42 have a corresponding relationship. The grating parameters of the third coupling grating 33 are designed as D3, and the grating parameters of the third coupling grating 43 are designed as A3. When D3 = A3, it indicates that the third coupling grating 33 and the third coupling grating 43 have a corresponding relationship. It is important to emphasize that the equal sign here means that there is a unique correspondence between the grating parameters such as the grating period, duty cycle, slot depth, and sidewall tilt angle of the coupled-in grating and the corresponding coupled-out grating. The grating can only work normally if this correspondence is met. It does not mean that the grating parameters such as the grating period, duty cycle, slot depth, and sidewall tilt angle of the coupled-in grating and the coupled-out grating are equal everywhere.

[0089] Specifically, see Figure 1 and Figure 2 When the optical module is working, the optical engine 1 selects and projects light rays at a certain virtual image distance position onto a coupling grating within the coupling region 3. The light rays then enter the transparent substrate 2 through this coupling grating. For example, if the optical engine 1 projects light rays with a virtual image distance of 2m onto the first coupling grating 31, the light rays will be propagated multiple times within the transparent substrate 2 and will eventually exit at all the positions of the first coupling gratings 41 within the coupling region 4. The arrangement of the multiple coupling gratings within the coupling region 4 is roughly as follows: Figure 2As shown, multiple coupling gratings are arranged on the transparent substrate 2 in a certain pattern, and each region is independent and does not interfere with the others. The area of ​​each minimum region can be freely divided. Any side length in the range of hundreds of nanometers to hundreds of micrometers can be defined and divided through grating design. The smaller the side length of each region, i.e., the area it occupies, the more uniform its distribution on the entire transparent substrate 2, and the better the display effect. When it is necessary to adjust the virtual image distance position, the optomechanical system 1 switches the light rays corresponding to the virtual image distance position to the position of another coupling grating for emission. For example, if the virtual image distance is adjusted from 2m to 5m, the corresponding light rays coupled in through the second coupling grating 32, after propagation through the transparent substrate 2, are emitted at all the positions of the second coupling gratings 42 in the coupling region 4 and enter the human eye for imaging, thus realizing the change and adjustment of the virtual image distance.

[0090] Based on the above example, the optical module is designed to have three adjustable virtual image distance positions. That is, the optical module has three adjustable virtual image distance positions, such as the aforementioned 2m, 5m, and 10m virtual image distances. In this case, the image displayed by the optical module on one side of the coupling area 4 through the light guide device can include the 2m virtual image distance image, the 5m virtual image distance image, and the 10m virtual image distance image.

[0091] Of course, the coupling region 4 includes, but is not limited to, setting three different grating structures for the coupling gratings. Two or more different grating structures can also be set to accommodate the needs of virtual image distance adjustment. Furthermore, there is no limit to the number of each type of coupling grating; it can be designed according to specific requirements. Figure 2 The image only shows one arrangement of multiple coupling gratings in the coupling region 4, but in fact, this application does not specifically limit the specific arrangement of the coupling gratings in the coupling region 4.

[0092] In some examples of this application, the optical engine 1 includes a light source and an optical engine lens, and the distance between the light source and the optical engine lens is adjustable to emit light at different virtual image distance positions; wherein, the distance between the light source and the optical engine lens is set in a one-to-one correspondence with the virtual image distance positions.

[0093] According to the above example, the optical engine 1 includes a light source and an optical engine lens. The distance between the light source and the optical engine lens can be changed, thereby changing the position of the formed virtual image. The light source is, for example, an optical engine screen.

[0094] For example, the light source can be moved relative to the optomechanical lens so that the distance between the light source and the optomechanical lens can be changed.

[0095] For example, the optomechanical lens can be moved relative to the light source so that the distance between the light source and the optomechanical lens can be changed.

[0096] The virtual image distance of the entire optical module is related to the distance between the light source and the optical engine lens in the optical engine 1. Thus, adjusting the distance between the light source and the optical engine lens in the optical engine 1 provides the necessary condition for adjusting the virtual image distance of the optical module.

[0097] In the embodiments of this application, the specific value of the change in the virtual image distance position of the optical module is determined by the distance of the light source inside the optical engine 1 relative to the optical engine lens. There is a corresponding relationship between the two, which can be determined by the calibration process. This will not be described in detail here.

[0098] In some examples of this application, the optical engine 1 is a display optical engine, and the emitted light carries image information. The light emitted by the optical engine 1 can cover the coupling region 3; or, the optical engine 1 is configured to be movable relative to the coupling region 3. The relative position between the light source and the optical engine lens can be varied to project corresponding light onto the target coupling grating within the coupling region 3.

[0099] According to one method in the above example, the light ray emitted by the optomechanical 1 corresponding to the target virtual image distance position, after being projected onto the coupling region 3, can cover the entire coupling region 3. However, only the coupling grating corresponding to this light ray can couple the light ray into the transparent substrate 2 and propagate through total internal reflection, and then couple it out through the coupling region 4. Specifically, see [link to relevant documentation]. Figure 2 The optomechanical system 1 selects to project the light rays corresponding to the virtual image distance position onto one of the coupling gratings in the coupling region 3. The light rays enter the transparent substrate 2 through the coupling grating and propagate to the coupling region 4 in a state of total internal reflection.

[0100] According to another method in the above example, the optical engine 1 can be designed to be movable to adjust the emission angle of the light. In this case, the light emitted by the optical engine 1 does not need to cover the entire coupling area 3. By adjusting the emission angle of the light emitted by the optical engine 1, the light can be directly aligned with the corresponding coupling grating.

[0101] In some examples of this application, the coupling-in region 3 and the coupling-out region 4 are disposed at intervals on the same surface of the transparent substrate 2, or are disposed on two opposite surfaces of the transparent substrate 2.

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

[0103] The optical module provided in this application is a diffractive waveguide optical solution, which has the function of adjustable virtual image distance position, and can make the optical display effect more realistic.

[0104] Optionally, the transparent substrate 2 may be made of glass, resin, or ceramic.

[0105] Optionally, the coupling-in grating and the coupling-out grating are thin-film diffraction gratings.

[0106] The coupled-in grating and the coupled-out grating can be designed as extremely thin grating film layers, which makes the formed light guide device thin and light, which is conducive to realizing the thin and light design of the optical module.

[0107] Optionally, the thickness of a single coupled grating can range from 3 micrometers to hundreds of micrometers.

[0108] For example, the thickness of a single coupled grating ranges from 3 micrometers to 150 micrometers.

[0109] Optionally, the coupled-in grating and the coupled-out grating can be thin-film diffraction gratings such as surface relief gratings or volume holographic gratings.

[0110] The optical module provided in this application is a diffractive waveguide augmented reality optical solution, which can be applied to electronic devices, especially head-mounted display products. It solves the problem of difficult adjustment of the virtual image distance in waveguide-based augmented reality products, and essentially resolves the convergence conflict issue that occurs when users wear waveguide-based augmented reality products, providing users with a more realistic augmented reality experience.

[0111] In some examples of this application, by adjusting at least one of the grating parameters of the coupled-in grating and the coupled-out grating, such that at least two different coupled-in gratings are formed in the coupled-in region 3, at least two different coupled-out gratings are formed in the coupled-out region 4, and each coupled-in grating has at least one corresponding coupled-out grating in the coupled-out region 4.

[0112] Different gratings have different structures depending on the design of their parameters.

[0113] According to another embodiment of this application, a display control method for an optical module as described above is provided, see [link to relevant documentation]. Figure 4 The display control method includes the following steps:

[0114] Step 401: Obtain the target virtual image distance position;

[0115] Step 402: Based on the target virtual image distance position, control the optomechanic to emit corresponding light rays and project the light rays onto the coupling area 3 on the transparent substrate 2;

[0116] Step 403: The light is coupled into the transparent substrate 2 through the coupling region 3, and propagates through the transparent substrate 2 by total internal reflection to the coupling region 4. The light is then emitted through at least one target coupling grating in the coupling region 4, and the resulting virtual image is presented at the target virtual image position.

[0117] The target virtual image distance position is the virtual image distance position that the optical module wants to present, and the coupling grating into which the corresponding light rays are coupled is defined as the target coupling grating.

[0118] The display control method for the optical module provided in this application embodiment enables the optical module to have a virtual image distance adjustment function. In this way, the application scenarios of the optical module are further improved and enriched, and the optical display effect is made more realistic.

[0119] The display control method for the optical module provided in this application embodiment can be applied to diffractive waveguide augmented reality optical solutions, specifically to electronic devices, especially head-mounted display products. It solves the problem of difficult adjustment of the virtual image distance in waveguide-based augmented reality products, and essentially resolves the convergence conflict issue that occurs when users wear waveguide-based augmented reality products, providing users with a more realistic augmented reality experience.

[0120] According to another aspect of the embodiments of this application, a head-mounted display device is also provided, the head-mounted display device including a housing and an optical module as described above.

[0121] The head-mounted display device is, for example, an AR head-mounted device, including AR glasses or an AR helmet, etc., and this application embodiment does not impose specific limitations on it.

[0122] In some examples of this application, the head-mounted display device is a smart glasses or a smart helmet, which includes: a front frame assembly, on which a left lens mounting portion and a right lens mounting portion are provided, and a bridge portion is provided between the left lens mounting portion and the right lens mounting portion.

[0123] The optical modules are configured in two parts. One optical module has a transparent substrate 2 located within the left lens mounting portion, and its optical engine 1 is located at the end of the left lens mounting portion away from the bridge of the nose, opposite to the coupling area 3 on the transparent substrate 2. The coupling area 4 on the transparent substrate 2 is opposite to the user's left eye. The other optical module has a transparent substrate 2 located within the right lens mounting portion, and its optical engine 1 is located at the end of the right lens mounting portion away from the bridge of the nose, opposite to the coupling area 3 on the transparent substrate 2. The coupling area 4 on the transparent substrate 2 is opposite to the user's right eye.

[0124] According to the above example, the head-mounted display device further includes: a head-mounted wearing component and a frame-type wearing component, wherein the head-mounted wearing component and the frame-type wearing component are detachably connected to the front frame component so that the head-mounted wearing component and the frame-type wearing component can be interchangeably fitted to the front frame component.

[0125] The specific implementation methods of the display control method of the optical module and the head-mounted display device in this application can be referred to the above-described embodiments of the optical module. Therefore, they have at least all the beneficial effects brought about by the technical solutions of the above-described embodiments, and will not be described in detail here.

[0126] The above embodiments mainly describe 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. For the sake of brevity, they will not be elaborated here.

[0127] While specific embodiments of this application have been described in detail by way of examples, those skilled in the art should understand that the above examples are for illustrative purposes only and are not intended to limit the scope of this application. Those skilled in the art should understand that modifications can be made to the above embodiments without departing from the scope and spirit of this application. The scope of this application is defined by the appended claims.

Claims

1. An optical module, characterized in that, include: Optical mechanism (1) is used to emit light rays at different virtual image distance positions so that the virtual image of the optical module can be presented at multiple virtual image distance positions, and each type of light ray corresponds to a virtual image distance position; The light guide device includes a transparent substrate (2) and a coupling region (3) and a coupling region (4) disposed on the transparent substrate (2). The coupling region (3) includes multiple coupling gratings with different grating structures. All the coupling gratings are located on the same surface of the transparent substrate (2) and form partitions within the coupling region (3). Each coupling grating is opposite to the optomechanism (1). The coupling region (3) is configured to couple light rays at different virtual image distance positions and to allow the coupled light rays to be totally internally reflected within the transparent substrate (2) and propagate to the coupling region (4). The coupling region (4) is used to couple out light rays propagating to the coupling region (4). The coupling region (4) includes a plurality of coupling gratings arranged in an array. The plurality of coupling gratings include at least two different grating structures, and each grating structure is used to couple out light rays at a virtual image distance position corresponding to that grating. Within the coupling region (4), coupling gratings with the same grating structure are used to couple out light rays at the same virtual image distance position. The number of coupling gratings n1 in the coupling region (3) and the number of adjustable virtual image distance positions n2 of the optical module satisfy n1=n2, and both n1 and n2 are greater than or equal to 2, so that the optical module can achieve adjustment of at least two virtual image distance positions. Each of the coupled-in gratings is configured to couple in a light ray at a virtual image distance position corresponding to its own grating structure, and each of the coupled-in gratings has at least one coupled-out grating corresponding to it in the coupled-out region (4).

2. The optical module according to claim 1, characterized in that, When the optical module has three adjustable virtual image distance positions, the coupling region (4) includes a first coupling grating (41), a second coupling grating (42) and a third coupling grating (43), and the first coupling grating (41), the second coupling grating (42) and the third coupling grating (43) are respectively used to couple out light rays at three different virtual image distance positions; The first coupling grating (41), the second coupling grating (42) and the third coupling grating (43) are each configured as at least one.

3. The optical module according to claim 2, characterized in that, The coupling region (3) includes a first coupling grating (31), a second coupling grating (32) and a third coupling grating (33); The first coupling grating (31) is used to couple in the light corresponding to the first target virtual image distance position and make the coupled light propagate through total internal reflection in the transparent substrate (2) to the coupling region (4), and then couple out through the first coupling grating (41) corresponding to the first coupling grating (31); The second coupling grating (32) is used to couple in the light corresponding to the virtual image distance position of the second target and make the coupled light propagate through total internal reflection in the transparent substrate (2) to the coupling region (4), and then couple out through the second coupling grating (42) corresponding to the second coupling grating (32); The third coupling grating (33) is used to couple in the light corresponding to the third target virtual image distance position and make the coupled light propagate through total internal reflection in the transparent substrate (2) to the coupling region (4), and then couple out through the third coupling grating (43) corresponding to the third coupling grating (33).

4. The optical module according to claim 1, characterized in that, The optical engine (1) includes a light source and an optical engine lens, and the distance between the light source and the optical engine lens is set to be adjustable so as to emit light at different virtual image distance positions; wherein, the distance between the light source and the optical engine lens is set in a one-to-one correspondence with the virtual image distance position.

5. The optical module according to claim 4, characterized in that, The optical engine (1) is a display optical engine, and the light emitted carries image information; The light emitted by the optical engine (1) can cover the coupling region (3); or, The optomechanism (1) is configured to move relative to the coupling region (3); The relative position between the light source and the optomechanical lens can be varied to project corresponding light rays onto the target coupling grating in the coupling region (3).

6. The optical module according to claim 5, characterized in that, The coupling-in region (3) and the coupling-out region (4) are disposed on the same surface of the transparent substrate (2) at intervals, or on two opposite surfaces of the transparent substrate (2).

7. The optical module according to claim 1, characterized in that, The light guiding device is a diffractive waveguide device.

8. The optical module according to claim 1, characterized in that, By adjusting the grating parameters of the coupled-in grating and the coupled-out grating, at least two different coupled-in gratings can be formed in the coupled-in region (3), at least two different coupled-out gratings can be formed in the coupled-out region (4), and each coupled-in grating has at least one corresponding coupled-out grating in the coupled-out region (4); wherein, the grating parameters include at least one of grating period, duty cycle, slot depth and sidewall tilt angle.

9. A display control method for an optical module as described in any one of claims 1-8, characterized in that, The display control method includes: Obtain the target virtual image distance position; Based on the target virtual image distance position, the optomechanic is controlled to emit corresponding light rays and project the light rays onto the coupling area on the transparent substrate; The light rays are coupled into the transparent substrate through the coupling region, and then propagate through total internal reflection in the transparent substrate to the coupling region. The light rays are then emitted through at least one target coupling grating in the coupling region, and the resulting virtual image is presented at the target virtual image position.

10. A head-mounted display device, characterized in that, include: case; as well as The optical module as described in any one of claims 1-8.

11. The head-mounted display device according to claim 10, characterized in that, The head-mounted display device is smart glasses or a smart helmet, and includes: A front frame assembly, wherein a left lens mounting portion and a right lens mounting portion are provided on the front frame assembly, and a bridge portion is provided between the left lens mounting portion and the right lens mounting portion; The optical module is configured as two: One of the optical modules has a transparent substrate (2) disposed in the left lens mounting portion, and the optical engine (1) of the optical module is disposed at the end of the left lens mounting portion away from the bridge of the nose and is opposite to the coupling area (3) on the transparent substrate (2), and the coupling area (4) on the transparent substrate (2) is opposite to the user's left eye. Another transparent substrate (2) of the optical module is disposed in the right lens mounting part, and the optical engine (1) of the optical module is disposed at one end of the right lens mounting part away from the bridge of the nose and opposite to the coupling area (3) on the transparent substrate (2), and the coupling area (4) on the transparent substrate (2) is opposite to the user's right eye.

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