Optical module, display control method, and head-mounted display device

Abstract

Embodiments of the present application provide an optical module, a display control method and a head-mounted display device. The optical module comprises an optical engine and a light guide device. The optical engine is configured to emit a plurality of different light rays, so that a virtual image of the optical module can be presented at a plurality of different virtual image distances, and each type of light ray corresponds to a virtual image distance. The light guide device comprises a transparent substrate, and a coupling-in region and a coupling-out region arranged on the transparent substrate. The coupling-in region comprises a plurality of coupling-in devices, and each coupling-in device is configured to couple in a light ray corresponding to a virtual image distance of the coupling-in device, and enable the coupled-in light ray to propagate by total reflection in the transparent substrate. The coupling-out region is configured to couple out the light ray propagating to the coupling-out region, so that the formed virtual image is presented at a target virtual image distance. The optical module has the function of adjustable virtual image distance.

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 ability to adjust the virtual image distance in AR products has long been a challenge for AR manufacturers. AR products without adjustable virtual image distance significantly limit their application scenarios, and the user experience is greatly diminished due to convergence conflict. Currently, AR products mainly utilize optical solutions such as freeform surfaces, Birdbath, arrayed waveguides, and diffractive waveguides. Among these, only the Birdbath optical solution allows for virtual image distance adjustment by varying the distance between the screen and the Birdbath mirror. The other optical solutions lack a mature virtual image distance adjustment mechanism like Birdbath, leaving a gap in the AR market that urgently needs to be filled. Summary of the Invention

[0003] 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, which solves the problem that diffractive waveguides do not have virtual image distance adjustment function when used in AR products.

[0004] In a first aspect, this application provides an optical module. The optical module includes:

[0005] An optical engine is used to emit a variety of different rays of light so that the virtual image of the optical module can be presented at multiple different virtual image distance positions, and each ray of light corresponds to a virtual image distance position;

[0006] A light guiding device includes a transparent substrate and a coupling-in region and a coupling-out region disposed on the transparent substrate;

[0007] The coupling region includes multiple coupling devices, and each coupling device is used to couple light rays at the virtual image distance position corresponding to the coupling device, so that the coupled light rays can propagate by total internal reflection within the transparent substrate.

[0008] The coupling region is used to couple out the light rays that have propagated to the coupling region so that the formed virtual image appears at the target virtual image distance position.

[0009] 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; 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.

[0010] Optionally, the optical engine is a display optical engine, and the emitted light carries image information;

[0011] The light emitted by the optical engine can cover the coupling region; or,

[0012] The optomechanism is configured to move relative to the coupling region;

[0013] 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.

[0014] Optionally, the coupling region includes a plurality of coupling devices, and the plurality of coupling devices are arranged in blocks within the coupling region; wherein, the coupling device is a coupling grating.

[0015] Optionally, the coupling region includes a plurality of coupling gratings stacked in a target order;

[0016] Light rays coupled in by any of the coupling gratings can be coupled out by at least one of the corresponding coupling gratings in the coupling-out region.

[0017] Optionally, when the optical module is configured to have three adjustable virtual image distance positions, the optomechanic is configured to emit at least a first ray, a second ray, and a third ray, the first ray, the second ray, and the third ray being used to present the virtual image of the optical module at three different virtual image distance positions;

[0018] The plurality of coupling devices include a first coupling grating, a second coupling grating, and a third coupling grating;

[0019] The first coupling grating is used to couple in the first light beam and cause the first light beam to propagate through total internal reflection within the transparent substrate to the coupling out region;

[0020] The second coupling grating is used to couple in the second light beam and cause the second light beam to propagate through total internal reflection within the transparent substrate to the coupling out region;

[0021] The third coupling grating is used to couple in the third light ray and cause the third light ray to propagate through total internal reflection within the transparent substrate to the coupling area.

[0022] Optionally, the coupling region includes a first coupling grating, a second coupling grating, and a third coupling grating stacked from top to bottom on the transparent substrate;

[0023] The first light ray is coupled out through the third coupling grating; the second light ray is coupled out through the third coupling grating and the second coupling grating; the third light ray is coupled out through the third coupling grating, the second coupling grating, and the first coupling grating; or...

[0024] The first light ray is coupled out through the third coupling grating, the second light ray is coupled out through the second coupling grating, and the third light ray is coupled out through the first coupling grating.

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

[0026] Optionally, the number of coupled devices in the coupled region matches the number of adjustable virtual image distance positions of the optical module.

[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 and project the light rays onto the target coupling device within the coupling region;

[0030] The light rays are coupled into the transparent substrate through the target coupling area, and after total internal reflection within the transparent substrate, they propagate to the coupling area and are emitted, ultimately forming a virtual image that appears at the target virtual image location.

[0031] Thirdly, this application provides a head-mounted display device. The head-mounted display 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] The beneficial effects of this application are as follows:

[0040] According to the optical module provided in this application embodiment, the coupling area on the transparent substrate is divided into multiple modules to form multiple coupling gratings. Each coupling grating can couple in a corresponding type of light to form a virtual image distance position. Thus, according to the required virtual image distance position, light at the corresponding virtual image distance position can be coupled in through a coupling grating. The coupled light can then propagate through total internal reflection within the transparent substrate to the coupling out region. At the coupling out region, the deflection angle of the light can be changed before it exits. The entire scheme realizes the virtual image distance adjustment function of the optical module. The optical module provided in this application embodiment enables the optical module to have a virtual image distance adjustment function, further enhancing and enriching the application scenarios of the optical module, and enabling more realistic optical display effects.

[0041] 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

[0042] 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.

[0043] Figure 1 This is a schematic diagram of the structure of the optical module provided in the embodiments of this application;

[0044] Figure 2 A schematic diagram of the coupling region of the light guide device provided in an embodiment of this application;

[0045] Figure 3 A schematic diagram of an image formed in the coupling region by the optical module provided in an embodiment of this application;

[0046] Figure 4 A flowchart of the display control method for the optical module provided in the embodiments of this application.

[0047] Explanation of reference numerals in the attached figures:

[0048] 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

[0049] 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.

[0050] 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.

[0051] 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.

[0052] 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.

[0053] 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.

[0054] The following is in conjunction with the appendix Figures 1 to 4 The optical module, display control method, and head-mounted display device provided in the embodiments of this application will be described in detail.

[0055] 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.

[0056] 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 various types of light rays, enabling the virtual image of the optical module to be displayed at multiple different virtual image distance positions, with each type of light ray corresponding to a specific virtual image distance position. The light guide device includes a transparent substrate 2 and a coupling-in region 3 and a coupling-out region 4 disposed on the transparent substrate 2. The coupling-in region 3 includes multiple coupling devices, each of which couples in light rays at its corresponding virtual image distance position, allowing the coupled light rays to propagate via total internal reflection within the transparent substrate 2. The coupling-out region 4 couples out light rays propagating to it, so that the formed virtual image is displayed at the target virtual image distance position.

[0057] The distance between the human eye and the virtual image formed by the optical module is called the virtual image distance.

[0058] The target virtual image distance position is the position where the virtual image of the desired optical module is presented, and the coupling grating into which the corresponding light rays are coupled is defined as the target coupling grating.

[0059] According to the above embodiments of this application, the optical module mainly consists of an optomechanical unit 1 and a light guide device. The overall structure of the optical module is simple, requiring no major modifications to its structure. The entire optical module can be applied to, for example, AR products.

[0060] 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 disposed on the transparent substrate 2. The coupling-in region 3 is pre-divided into multiple sub-regions, and at least one coupling grating is disposed in each sub-region, thus forming multiple coupling gratings arranged in partitions within the entire coupling-in region 3.

[0061] Within the coupling region 3, multiple coupling gratings can couple different light rays to form virtual images at different virtual image distance positions. Different light rays are coupled into the transparent substrate 2 via different coupling gratings, and all can propagate through total internal reflection within the transparent substrate 2 to the coupling region 4. The light rays coupled out of the coupling region 4 can form virtual images at different virtual image distance positions, thus enabling the entire optical module to have an adjustable virtual image distance.

[0062] In a specific example, see Figure 2 The coupling zone 3 is divided into three coupling gratings, defined as: a first coupling grating 31, a second coupling grating 32, and a third coupling grating 33. The grating parameter of the first coupling grating 31 is designed as D1, the grating parameter of the second coupling grating 32 is designed as D2, and the grating parameter of the third coupling grating 33 is designed as D3. This allows the coupling zone 3 to couple light rays at three different virtual image distance positions. Thus, the entire optical module can have three adjustable virtual image distance positions. In this example, the entire optical module has three adjustable virtual image distance positions, such as 2m, 5m, and 15m virtual image distances. The image displayed in the output zone 4 via the light guide device is shown below. Figure 3 It can include images with a virtual image distance of 2m, 5m, and 15m.

[0063] It should be emphasized that, for the light guide device of this application, 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.

[0064] As a preferred embodiment of this application, the number of coupling gratings in the coupling region 3 can be set to 2 to 20.

[0065] It should be noted that if too many coupling gratings are set in the same 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 final imaging.

[0066] In the embodiments described above in this application, light rays coupled to different coupling gratings can be designed to be emitted from the same optomechanism 1. See also Figure 1 The optical engine 1 is capable of emitting light rays that form different virtual image distances.

[0067] The optical engine 1, for example, is a display optical engine, which can be used to emit light carrying image information. The light guide device, as a light transmission device, can be used to transmit the light emitted by the optical engine 1 and can 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.

[0068] Figure 1 A schematic diagram of a light guide device is shown. Figure 2 The coupling region 3 shown is disposed on the transparent substrate 2 of the light guide device; and the coupling region 4 is also disposed on the transparent substrate 2.

[0069] It should be noted that the coupling-in region 3 and the coupling-out region 4 can be disposed on the same surface of the transparent substrate 2. Of course, the coupling-in region 3 and the coupling-out region 4 can also be disposed on two opposite surfaces of the transparent substrate 2. This application does not impose specific restrictions on the placement of the coupling-in region 3 and the coupling-out region 4 on the transparent substrate 2.

[0070] The optical module provided in this application embodiment can be applied to, for example, AR products. It has the function of adjustable virtual image distance position, which can make the optical display effect more realistic.

[0071] In the above embodiments of this application, the coupling region 3 is provided with multiple coupling gratings of different grating structures, which can couple light rays at different virtual image distance positions, ultimately allowing the virtual image of the optical module to be presented at different virtual image distance positions. Specifically, in the coupling region 3, the grating structures of the multiple coupling gratings are different, and each type of grating structure can correspond to coupling light rays at a specific virtual image distance position, and the light rays at different virtual image positions will not interfere with each other.

[0072] It should be noted that for the 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.

[0073] According to the optical module provided in this application embodiment, the coupling area on the transparent substrate 2 is divided into multiple modules to form multiple coupling gratings in the coupling area 3. Each coupling grating can couple in a corresponding type of light, forming a virtual image distance position. Thus, according to the target virtual image distance position, the light at the corresponding virtual image distance position can be coupled in through a coupling grating in the coupling area 3, and the coupled light can be propagated through total internal reflection within the transparent substrate 2 to the coupling out region. At the position of the coupling out region 4, the deflection angle of the light can be changed for exit. The entire scheme realizes the virtual image distance adjustment function of the optical module. See [link to relevant documentation]. Figure 3 .

[0074] 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.

[0075] 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 set to be adjustable; 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.

[0076] 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.

[0077] 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.

[0078] 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.

[0079] 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.

[0080] 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.

[0081] 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. Alternatively, 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.

[0082] According to one of the above examples, after the light emitted by the optical engine 1 corresponding to the target virtual image distance position is projected onto the coupling region 3, the light can cover the entire coupling region 3. However, only the coupling grating corresponding to the wavelength of the light can couple the light into the transparent substrate 2 and propagate through total internal reflection, and then couple it out through the coupling region 4.

[0083] According to another approach in the above example, the optomechanism 1 can also be designed to be movable to adjust the exit angle of the light emitted by the optomechanism 1. In this case, the light emitted by the optomechanism 1 does not need to cover the entire coupling region 3, but can be directly aligned with the corresponding coupling grating by adjusting the exit angle of the light emitted by the optomechanism 1.

[0084] Furthermore, the optical engine 1 can be driven by external driving devices such as motors, and this application embodiment does not limit this.

[0085] See some examples in this application. Figure 2 The coupling region 3 includes a plurality of coupling devices, and the plurality of coupling devices are arranged in blocks within the coupling region 3; wherein, the coupling device is a coupling grating.

[0086] See Figure 2 The coupling region 3 includes, for example, three coupling gratings, namely... Figure 2 The first coupling grating 31, the second coupling grating 32 and the third coupling grating 33 shown in the figure have different grating structures and different grating parameters, corresponding to D1, D2 and D3 respectively. The three coupling gratings are set in blocks and located in the same plane.

[0087] It should be noted that the coupling region 3 includes, but is not limited to, setting three coupling gratings; the number of coupling gratings can be designed according to actual needs. For example, the number of coupling gratings in the coupling region 3 can be set to 2 to 20.

[0088] Preferably, the number of coupling gratings in the coupling region 3 is less than 15.

[0089] 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.

[0090] See some examples in this application. Figure 1 The coupling region 4 includes a plurality of coupling gratings stacked in a target order; light rays coupled in through any of the coupling gratings can be coupled out through at least one of the corresponding coupling gratings in the coupling region 4.

[0091] For the light rays corresponding to different virtual image distances emitted from the optomechanical 1 to be incident on the input grating and exited by the output grating, the correspondence between the input and output gratings must be satisfied. This 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 input and output gratings. 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 are exactly the same for both the input and output gratings.

[0092] The coupling region 4 contains multiple coupling gratings, and each coupling grating, based on its specific grating structure, only deflects light rays incident at a specific angle.

[0093] In this application, multiple coupling gratings within the coupling region 4 are stacked. Through pre-calculation, light transmitted via total internal reflection through the transparent substrate 2 can be acted upon by only one layer of coupling gratings. Of course, multiple layers of coupling gratings can also be used. Specifically, the deflection angle of the light after being acted upon by the upper layer of coupling gratings exactly satisfies the incident angle of the lower layer of coupling gratings, thus allowing the light to be acted upon by two or even more layers of gratings.

[0094] See some examples in this application. Figures 1 to 3When the optical module is configured to have three adjustable virtual image distance positions, the optomechanical system 1 is configured to emit at least a first ray, a second ray, and a third ray, the first ray, the second ray, and the third ray being used to present the virtual image of the optical module at three different virtual image distance positions; the plurality of coupling devices include 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 first ray and cause the first ray to propagate through total internal reflection within the transparent substrate 2 to the coupling out region 4; the second coupling grating 32 is used to couple in the second ray and cause the second ray to propagate through total internal reflection within the transparent substrate 2 to the coupling out region 4; the third coupling grating 33 is used to couple in the third ray and cause the third ray to propagate through total internal reflection within the transparent substrate 2 to the coupling out region 4.

[0095] According to the above example, the coupling region 4 includes a first coupling grating 41, a second coupling grating 42, and a third coupling grating 43 stacked from top to bottom on the transparent substrate 2; the first light ray can be coupled out through the third coupling grating 43, the second light ray can be coupled out through the third coupling grating 43 and the second coupling grating 42, and the third light ray can be coupled out through the third coupling grating 43, the second coupling grating 42, and the first coupling grating 41. Alternatively, the first light ray can be coupled out through the third coupling grating 43, the second light ray can be coupled out through the second coupling grating 42, and the third light ray can be coupled out through the first coupling grating 41.

[0096] According to the above example of this application, the coupling region 3 is composed of three coupling gratings with different grating structures, namely a first coupling grating 31, a second coupling grating 32, and a third coupling grating 33. See [reference needed] Figure 2 These three coupling gratings have different grating parameters and can be defined as D1, D2, and D3, respectively. Each coupling grating corresponds to a ray at a virtual image distance position.

[0097] For example, see Figure 2 D1, D2, and D3 represent the grating parameters of the three coupling gratings corresponding to the light rays at virtual image distances of 2m, 5m, and 10m within the coupling region 3, respectively.

[0098] Light coupled into the coupling region 3 undergoes total internal reflection on the transparent substrate 2, and the position of the output region 4 is altered by a corresponding output grating to change the deflection angle of the light before it enters the human eye. (See also...) Figure 1The coupling region 4 is formed, for example, by stacking three coupling gratings with different grating structures: a first coupling grating 41, a second coupling grating 42, and a third coupling grating 43. The grating parameters corresponding to these three coupling gratings can be represented by A1, A2, and A3, respectively. It should be noted that, due to the characteristics of diffraction gratings, each coupling grating only deflects light rays incident at a specific angle, without altering the propagation path of other light rays that cannot be affected by the grating. Thus, when totally internally reflected light rays within the transparent substrate 2 of the light guide device irradiate the coupling region 4, the light rays may be affected by only one coupling grating or by a combination of multiple coupling gratings, depending on the design, resulting in various non-repeating scenarios.

[0099] For example, in one case, the correspondence between grating parameters such as grating period, duty cycle, slot depth, and sidewall tilt angle of the input and output gratings is as follows: Figure 1 and Figure 2 As shown, D1 = A3, D2 = A3 + A2, D3 = A3 + A2 + A1. Theoretically, the correspondence between the grating parameters of the coupling-in region and the coupling-out region has multiple matching cases due to the stacking of the coupling-out gratings at the beginning of the design. Only one of them is listed here.

[0100] Specifically, see Figure 1 and Figure 2 When the optical module is working normally, the optomechanical system 1 selects to project light at a certain virtual image distance position onto one of the coupling gratings in the coupling region 3. The light then enters the transparent substrate 2 through the coupling grating. For example, the optomechanical system 1 projects light at a virtual image distance position of 2m onto the first coupling grating 31. The light is conducted in the transparent substrate 2 and finally exits through the third coupling grating 43 in the coupling region 4 to form an image in the human eye. When the virtual image distance position needs to be adjusted, for example, from 2m to 5m, the corresponding light is coupled into the second coupling grating 32. After total internal reflection in the transparent substrate 2, the light is emitted through the two diffraction gratings of the third coupling grating 43 and the second coupling grating 42 and enters the human eye to form an image, thus realizing the change and adjustment of the virtual image distance.

[0101] In some examples of this application, the light guiding device is a diffractive waveguide device.

[0102] 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.

[0103] Optionally, the transparent substrate 2 of the light guide device may be made of glass, resin, or ceramic.

[0104] In the embodiments of this application, each coupling grating in the coupling region 4 is designed as an extremely thin grating film layer, and the grating film layers do not affect each other, so the coupling gratings can be stacked in multiple layers. The modulation of the coupling gratings can be adjusted according to the grating parameters of the corresponding input gratings, such as grating period, duty cycle, slot depth, and sidewall tilt angle, so that the stacked layers can meet the requirements of different corresponding relationships of different input gratings.

[0105] Optionally, the thickness of a single coupled grating can range from 3 micrometers to hundreds of micrometers.

[0106] For example, the thickness of a single coupled grating ranges from 3 micrometers to 150 micrometers.

[0107] 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.

[0108] In some examples of this application, the number of coupling devices in the coupling region 3 matches the number of adjustable virtual image distance positions of the optical module.

[0109] According to the light guide device provided in the embodiments of this application, the division of the different blocks of the coupling-in region 3 and 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.

[0110] 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:

[0111] Step 401: Obtain the target virtual image distance position;

[0112] 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 target coupling device within the coupling area;

[0113] Step 403: The light rays are coupled into the transparent substrate through the target coupling area, and after total internal reflection in the transparent substrate, they propagate to the coupling area and are emitted, and the resulting virtual image is presented at the target virtual image position.

[0114] 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.

[0115] 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 head-mounted display 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.

[0116] 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.

[0117] 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.

[0118] 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.

[0119] 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.

[0120] According to the above example, the head-mounted display device may further include: 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.

[0121] 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.

[0122] 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.

[0123] 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 engine (1) is used to emit a variety of different light rays so that the virtual image of the optical module can be presented at multiple different virtual image distance positions, and each 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 a plurality of coupling gratings arranged in blocks within the coupling region (3), and each coupling grating is used to couple light rays at the virtual image distance position corresponding to the coupling grating, so that the coupled light rays can propagate by total internal reflection within the transparent substrate (2). The coupling region (4) is used to couple out the light rays that have propagated to the coupling region (4) so ​​that the formed virtual image is presented at the target virtual image distance position; The coupling region (4) includes a plurality of coupling gratings stacked in the target order; light rays coupled in through any of the coupling gratings can be coupled out through at least one of the corresponding coupling gratings in the coupling region (4).

2. 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; wherein, the distance between the light source and the optical engine lens is set to correspond one-to-one with the virtual image distance position.

3. The optical module according to claim 2, 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 within the coupling region (3).

4. The optical module according to claim 1, characterized in that, When the optical module is configured to have three adjustable virtual image distance positions, the optical engine (1) is configured to emit at least a first ray, a second ray, and a third ray, the first ray, the second ray, and the third ray being used to present the virtual image of the optical module at three different virtual image distance positions; The coupling grating 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 first light and cause the first light to propagate through total internal reflection within the transparent substrate (2) to the coupling out region (4). The second coupling grating (32) is used to couple in the second light and cause the second light to propagate through total internal reflection within the transparent substrate (2) to the coupling out region (4). The third coupling grating (33) is used to couple in the third light ray and make the third light ray propagate through total internal reflection within the transparent substrate (2) to the coupling out region (4).

5. The optical module according to claim 4, characterized in that, The coupling region (4) includes a first coupling grating (41), a second coupling grating (42) and a third coupling grating (43) stacked from top to bottom on the transparent substrate (2). The first ray is coupled out through the third coupling grating (43), the second ray is coupled out through the third coupling grating (43) and the second coupling grating (42), and the third ray is coupled out through the third coupling grating (43), the second coupling grating (42) and the first coupling grating (41); or, The first light ray is coupled out through the third coupling grating (43), the second light ray is coupled out through the second coupling grating (42), and the third light ray is coupled out through the first coupling grating (41).

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

7. The optical module according to claim 1, characterized in that, The number of coupling gratings in the coupling region (3) matches the number of adjustable virtual image distance positions of the optical module.

8. A display control method for an optical module as described in any one of claims 1-7, 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 target coupling grating within the coupling region; The light rays are coupled into the transparent substrate through the target coupling grating, and after total internal reflection within the transparent substrate, they propagate to the coupling region and are emitted, ultimately forming a virtual image at the target virtual image position.

9. 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.

10. The head-mounted display device according to claim 9, 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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