Optical device, head mounted display device and adjustment method of head mounted display device

Abstract

The embodiment of the present application provides an optical device, a head-mounted display device and an adjustment method for the head-mounted display device. The optical device includes an optical substrate and a first transparent substrate, the optical substrate and the first transparent substrate are stacked; the optical substrate has a coupling-in area and a coupling-out area, the first transparent substrate has a first area and a second area; the first transparent substrate is provided with a first light modulation component in the first area, the first light modulation component is configured to convert the image light projected by the display screen into circularly polarized light; the first transparent substrate is provided with a zoom group in the second area, the zoom group includes at least one sub-zoom group, the sub-zoom group includes a first liquid crystal layer and a second liquid crystal layer, the first liquid crystal layer is configured to switch between a first orientation and a second orientation to transmit circularly polarized light of different rotation directions to the second liquid crystal layer; the second liquid crystal layer forms virtual image planes of at least two focal lengths according to the received circularly polarized light of different rotation directions.

Description

Technical Field

[0001] The embodiments of the present application relate to the field of augmented reality technology. More specifically, the embodiments of the present application relate to an optical device, a head-mounted display device, and an adjustment method for the head-mounted display device. Background Art

[0002] In AR (Augmented Reality) products, such as AR head-mounted display devices, optical waveguides are usually used as core components. The incident light can be transmitted in the optical waveguide based on the principle of total reflection. A diffraction grating is set on the surface of the optical waveguide, which is used to couple the light into the optical waveguide or couple the light out of the optical waveguide for display imaging.

[0003] The essence of AR technology is to achieve interaction between people and the augmented real world through the integration of the virtual world and the real world. When the human eye views an object, the parallax between the left and right eyes can form a three-dimensional image in the human brain, and when viewing images in different positions, the left and right eyeballs can automatically adjust so that the two images of the left and right eyes can be integrated in the human brain.

[0004] In the related art, a single-focus optical design is usually adopted. The image distance of the image presented by the single-focus optical design is constant for the human eye, so that the human eye does not need to adjust the diopter when viewing the image. However, due to the conflict between the convergence rotation of the human eye and the constant diopter adjustment (i.e., convergence conflict), the human eye is prone to eye fatigue and dizziness when continuously viewing dynamic 3D images. Summary of the invention

[0005] The purpose of this application is to provide a new technical solution for an optical device, a head-mounted display device, and an adjustment method for the head-mounted display device.

[0006] In a first aspect, the present application provides an optical device. The optical device comprises

[0007] The optical device comprises an optical base and a first transparent substrate, wherein the optical base and the first transparent substrate are stacked;

[0008] The optical base has an incoupling region and an outcoupling region, and the first transparent substrate has a first region corresponding to the incoupling region and a second region corresponding to the outcoupling region;

[0009] A first light modulating component is disposed on a side of the first transparent substrate facing away from the optical base and in the first region, wherein the first light modulating component is configured to convert image light projected by a target display screen into circularly polarized light;

[0010] A zoom group is disposed on a side of the first transparent substrate away from the optical base and in the second region, the zoom group includes at least one sub-zoom group, the sub-zoom group includes a first liquid crystal layer and a second liquid crystal layer, and the second liquid crystal layer is disposed away from the first transparent substrate relative to the first liquid crystal layer;

[0011] The first liquid crystal layer is configured to switch between a first orientation and a second orientation to transmit circularly polarized light of different rotation directions to the second liquid crystal layer; the second liquid crystal layer forms virtual image planes of at least two focal lengths according to the received circularly polarized light of different rotation directions.

[0012] Optionally, the first light modulation component includes a third liquid crystal layer, and the third liquid crystal layer is configured to convert the linearly polarized light into circularly polarized light.

[0013] Optionally, the first light modulation component further includes a fourth liquid crystal layer, the third liquid crystal layer and the fourth liquid crystal layer are stacked, and the fourth liquid crystal layer is arranged away from the first transparent substrate relative to the third liquid crystal layer;

[0014] The fourth liquid crystal layer is configured to convert image light projected by the display screen into linearly polarized light.

[0015] Optionally, the first liquid crystal layer is connected to an electronic control component, so that the first liquid crystal layer switches between a first orientation and a second orientation;

[0016] In the first orientation, the first liquid crystal layer can reflect circularly polarized light of a first rotation direction and can transmit circularly polarized light of a second rotation direction;

[0017] In the second orientation, the first liquid crystal layer can reflect circularly polarized light of the second rotation direction and transmit circularly polarized light of the first rotation direction.

[0018] Optionally, the first liquid crystal layer is a cholesteric liquid crystal layer.

[0019] Optionally, the second liquid crystal layer is a nematic liquid crystal layer.

[0020] Optionally, the zoom group includes three sub-zoom groups, and the first liquid crystal layer in each sub-zoom group is individually connected to an electric control component to form virtual image planes with six focal lengths.

[0021] Optionally, the optical device further comprises a second transparent substrate, the second transparent substrate is stacked with the optical base, and the first transparent substrate and the second transparent substrate are respectively located on two opposite sides of the optical base;

[0022] The second transparent substrate has a third area corresponding to the outcoupling area;

[0023] A second light modulation component and a zoom compensation group are arranged on a side of the third area away from the optical base, and the zoom compensation group is arranged close to the second transparent substrate relative to the second light modulation component;

[0024] The second light modulation component is configured to convert ambient light into circularly polarized light;

[0025] The zoom compensation group is configured to compensate for a zoom parameter of the zoom group.

[0026] Optionally, the zoom compensation group includes at least one sub-zoom compensation group, the sub-zoom compensation group includes a fifth liquid crystal layer and a sixth liquid crystal layer, and the sixth liquid crystal layer is arranged relative to the fifth liquid crystal layer and close to the second transparent substrate;

[0027] The fifth liquid crystal layer is configured to switch between a first orientation and a second orientation to project circularly polarized light of different rotation directions to the sixth liquid crystal layer; the sixth liquid crystal layer receives the circularly polarized light and transmits the circularly polarized light to the zoom group, wherein the optical focal length of the sixth liquid crystal layer is opposite to the optical focal length of the second liquid crystal layer to compensate for the zoom parameter of the zoom group.

[0028] Optionally, the second light modulation component comprises a seventh liquid crystal layer and an eighth liquid crystal layer, the seventh liquid crystal layer and the eighth liquid crystal layer are stacked, and the seventh liquid crystal layer is arranged away from the second transparent substrate relative to the eighth liquid crystal layer;

[0029] The seventh liquid crystal layer is configured to convert ambient light into linearly polarized light;

[0030] The eighth liquid crystal layer is configured to convert the linearly polarized light into circularly polarized light.

[0031] Optionally, the zoom compensation group includes three groups of sub-zoom compensation groups, the fifth liquid crystal layer in each sub-zoom compensation group is individually connected to an electric control component, and the optical focal length of the sixth liquid crystal layer in each sub-zoom compensation group is opposite to the optical focal length of the corresponding second liquid crystal layer.

[0032] In a second aspect, a head mounted display device is provided, wherein the head mounted display device is the optical device as described in the first aspect.

[0033] In a third aspect, a method for adjusting a head mounted display device is provided. The method comprises:

[0034] Obtain human eye information data;

[0035] Determine the human eye focusing position information according to the human eye information data;

[0036] The orientation of the first liquid crystal layer is adjusted according to the human eye focus position information, and the second liquid crystal layer forms virtual image planes of at least two focal lengths according to the received circularly polarized light of different rotation directions, so that the optical device can achieve zooming.

[0037] According to an embodiment of the present application, an optical device is provided. The optical device includes an optical base and a first transparent substrate, wherein a zoom group is arranged in a second area of ​​the first transparent substrate corresponding to the outcoupling area, wherein a first liquid crystal layer in the zoom group can switch between a first orientation and a second orientation, and the circularly polarized light of different rotation directions generated by the first liquid crystal layer is formed into different focuses at the human eye through the second liquid crystal layer, so that it is not easy for the viewer to have a convergence conflict when viewing a three-dimensional image, thereby ensuring the imaging quality. On the other hand, the zoom group includes a first liquid crystal layer and a second liquid crystal layer, which reduces the weight of the optical device, and the optical device is applied to a head-mounted display device to realize a lightweight head-mounted display device.

[0038] Other features and advantages of the present specification will become apparent from the following detailed description of exemplary embodiments of the present specification with reference to the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0039] The accompanying drawings, which are incorporated in and constitute a part of the specification, illustrate embodiments of the specification and, together with the description, serve to explain the principles of the specification.

[0040] Figure 1 Shown is a schematic diagram of the structure of an optical device provided in an embodiment of the present application.

[0041] Figure 2 Shown is a schematic structural diagram of the zoom group.

[0042] Figure 3 Shown is a schematic diagram of the electrical control principle of the zoom group.

[0043] Figure 4 Shown is a schematic diagram of the structure of a head mounted display device provided in an embodiment of the present application.

[0044] Description of reference numerals:

[0045] 1. Optical substrate; 10. Optical machine module; 100. Optical device;

[0046] 2. first transparent substrate; 21. first light modulating component; 211. third liquid crystal layer; 212. fourth liquid crystal layer; 22. zoom group; 221. sub-zoom group; 222. first liquid crystal layer; 223. second liquid crystal layer;

[0047] 3. second transparent substrate; 31. second light modulating component; 311. seventh liquid crystal layer; 312. eighth liquid crystal layer; 32. zoom compensation group; 321. sub-zoom compensation group; 322. fifth liquid crystal layer; 323. sixth liquid crystal layer;

[0048] 4. Head-mounted display device; 41. Spectacle frame; 42. Eye tracker. DETAILED DESCRIPTION

[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 of components and steps, numerical expressions and numerical values ​​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 in nature and is in no way intended to limit the present application, its application, or uses.

[0051] Techniques and equipment known to ordinary technicians in the relevant art may not be discussed in detail, but where appropriate, the techniques and equipment should be considered part of the specification.

[0052] In all examples shown and discussed herein, any specific values ​​should be interpreted as merely exemplary and not limiting. Therefore, other examples of the exemplary embodiments may have different values.

[0053] It should be noted that like reference numerals and letters refer to similar items in the following figures, and therefore, once an item is defined in one figure, it need not be further discussed in subsequent figures.

[0054] The present application provides an optical device 100. Figure 1-Figure 3 The optical device 100 includes: an optical substrate 1 and a first transparent substrate 2, and the optical substrate 1 and the first transparent substrate 2 are stacked.

[0055] The optical base 1 has a coupling-in region and a coupling-out region, and the first transparent substrate 2 has a first region corresponding to the coupling-in region and a second region corresponding to the coupling-out region.

[0056] A first light modulating component 21 is disposed on a side of the first transparent substrate 2 facing away from the optical base 1 and in the first region. The first light modulating component 21 is configured to convert image light projected from a target display screen into circularly polarized light.

[0057] The first transparent substrate 2 is located away from the optical base 1, and a zoom group 22 is arranged in the second area. The zoom group 22 includes at least one sub-zoom group 221. The sub-zoom group 221 includes a first liquid crystal layer 222 and a second liquid crystal layer 223. The second liquid crystal layer 223 is arranged away from the first transparent substrate 2 relative to the first liquid crystal layer 222.

[0058] The first liquid crystal layer 222 is configured to switch between a first orientation and a second orientation to transmit circularly polarized light of different rotation directions to the second liquid crystal layer 223; the second liquid crystal layer 223 forms virtual image planes of at least two focal lengths according to the received circularly polarized light of different rotation directions.

[0059] In the above embodiment, the optical device 100 includes an optical substrate 1 and a first transparent substrate 2, wherein the first transparent substrate 2 and the optical substrate 1 are stacked, and the first transparent substrate 2 plays a role in protecting the optical substrate 1, for example, playing a role in dustproofing and waterproofing the optical substrate 1. In a specific embodiment, the optical substrate 1 and the first transparent substrate 2 can be fixed by bonding, for example, they can be fixed by optical glue.

[0060] In the above embodiment, the first transparent substrate 2 is arranged close to the human eye side and the light source side, wherein the human eye side and the light source side are located on the same side. For example, an optical machine module 10 is arranged on the light source side, and the image light emitted by the optical machine module 10 passes through the first transparent substrate 2 and is then coupled into the optical base 1 through the coupling region of the optical base 1.

[0061] The optical substrate 1 has a coupling-in region and a coupling-out region, wherein a coupling-in grating is arranged in the coupling-in region, and a coupling-out grating is arranged in the coupling-out region, wherein the coupling-in grating couples the light passing through the first region of the first transparent substrate 2 into the optical substrate 1, and the light coupled into the optical substrate 1 is totally reflected in the optical substrate 1, and can finally be coupled out from the coupling-out grating of the optical substrate 1, and finally emitted through the second region of the first lens substrate, and finally enters the human eye.

[0062] In this embodiment, the provided optical device performs zooming based on circularly polarized light, so the light coupled into the optical substrate 1 needs to be circularly polarized light.

[0063] Specifically, a first light modulator 21 is arranged in the first area on the side of the first transparent substrate 2 facing away from the optical base 1, wherein the first light modulator 21 can convert the image light projected by the display screen into circularly polarized light. Specifically, the light emitted by the display screen and the external ambient light can be converted into circularly polarized light. However, since the external ambient light enters the optical base 1, and since the transmission condition of the external ambient light does not meet the total reflection condition, the external ambient light will not be transmitted in the optical base 1. The light transmitted from the first area of ​​the first transparent substrate 2 to the optical base 1, ultimately only the image light projected by the optical machine module 10 can be transmitted to the outcoupling area of ​​the optical base 1, and emitted through the zoom group 22 of the first transparent substrate 2.

[0064] The circularly polarized light converted by the first light modulation component 21 is coupled into the optical base 1 from the coupling-in region of the optical base 1. The converted circularly polarized light is totally reflected in the optical base 1, and then coupled out from the coupling-out region of the optical base 1. Finally, it is emitted through the second region of the first lens substrate and finally enters the human eye.

[0065] In the above embodiment, a zoom group 22 is arranged on the side of the first transparent substrate 2 away from the optical base 1 and in the second area. The zoom group 22 is used to zoom the circularly polarized light, so that the image projected by the display screen can be presented in a virtual image plane of various focal lengths, so as to avoid convergence conflicts when the human eye views through the optical device, and avoid the phenomenon of eye fatigue and dizziness when the human eye needs to readjust the focus and convergence during the switching process between reality and virtuality.

[0066] Specifically, a zoom group 22 is arranged on the side of the first transparent substrate 2 away from the optical base 1 and in the second area, wherein the zoom group 22 includes at least one sub-zoom group 221. According to the type of circularly polarized light transmitted to the second liquid crystal layer 223, the focal length of each sub-zoom group 221 can be adjusted, so that the zoom group 22 has different focal lengths, and then the image projected by the display screen is zoomed, so that the optical device can present the picture in the image in a virtual image plane corresponding to a variety of focal lengths as needed, that is, a multi-focal plane display is formed. In this embodiment, at least two focal planes can be realized to avoid convergence conflicts when the human eye views through the optical device, and to avoid eye fatigue and dizziness when the human eye needs to readjust the focus and adjust the convergence during the switching process between reality and virtuality.

[0067] Specifically, the sub-zoom group 221 includes a first liquid crystal layer 222 and a second liquid crystal layer 223, wherein the first liquid crystal layer 222 is attached to the surface of the second region of the first transparent substrate 2, and the second liquid crystal layer 223 is attached to the first liquid crystal layer 222. Alternatively, the first liquid crystal layer 222 and the second liquid crystal layer 223 constitute a composite film layer, and the composite film layer is attached to the surface of the second region of the first transparent substrate 2. In this embodiment, the structure of the sub-zoom group 221 is limited, and the weight of the optical device can be reduced. The optical device is applied to the head-mounted display device 4, and a lightweight design of the head-mounted display device 4 is achieved.

[0068] The first liquid crystal layer 222 can switch between a first orientation and a second orientation, and the second liquid crystal layer 223 generates different wavefront modulations for the circularly polarized light of the first rotation direction and the circularly polarized light of the second rotation direction, which is specifically manifested in different focal lengths for the circularly polarized light of the first rotation direction and the circularly polarized light of the second rotation direction.

[0069] For example, when the first liquid crystal layer 222 allows the transmission of circularly polarized light of the second rotation direction, the second liquid crystal layer 223 has a first focal length correspondingly; when the second liquid crystal layer 223 allows the transmission of circularly polarized light of the first rotation direction, the second liquid crystal layer 223 has a second focal length correspondingly. In this embodiment, the first liquid crystal layer 222 is actively controlled so that the first liquid crystal layer 222 can selectively allow the transmission of circularly polarized light of the first rotation direction, or allow the transmission of circularly polarized light of the second rotation direction.

[0070] That is, when the first liquid crystal layer 222 allows the circularly polarized light of the second rotation direction to be transmitted, after the circularly polarized light of the second rotation direction passes through the second liquid crystal layer 223, the second liquid crystal layer 223 has a focal length for the circularly polarized light of the second rotation direction, namely, the first focal length;

[0071] When the first liquid crystal layer 222 allows the circularly polarized light of the first rotation direction to pass through, after the circularly polarized light of the first rotation direction passes through the second liquid crystal layer 223 , the second liquid crystal layer 223 has another focal length, ie, the second focal length, for the circularly polarized light of the first rotation direction.

[0072] In the process of continuously switching the state of the first liquid crystal layer 222, the focal length of the second liquid crystal layer 223 for circularly polarized light of different rotation directions is continuously switched between the first focal length and the second focal length, so that the focal length of the sub-zoom layer is continuously changed, so that the picture in the image is presented in the virtual image plane corresponding to the two focal lengths (for example, the circular polarized light of the first rotation direction corresponds to the virtual image plane of the second focal length, and the circular polarized light of the second rotation direction corresponds to the virtual image plane of the first focal length); optionally, when the zoom group 22 includes multiple sub-zoom layers, the focal length of the zoom group 22 is switched between multiple focal lengths, and the picture in the image is presented in the virtual image plane corresponding to the multiple focal lengths, that is, a multi-focal plane display is formed.

[0073] For example, it can also be understood that: the second liquid crystal layer 223 is a liquid crystal layer with different focusing effects on circularly polarized light of the first rotation direction and circularly polarized light of the second rotation direction, and the second liquid crystal layer 223 forms virtual image planes with different focal lengths according to the received circularly polarized light of different rotation directions, for example, the first liquid crystal layer 222 allows the circularly polarized light of the second rotation direction to pass through, wherein the second liquid crystal layer 223 receives left-handed polarized light to focus the circularly polarized light of the second rotation direction at the first position to form a virtual image plane. At this time, the state of the first liquid crystal layer 222 is actively switched, so that the first liquid crystal layer 222 allows the circularly polarized light of the first rotation direction to pass through, wherein the second liquid crystal layer 223 receives the circularly polarized light of the first rotation direction to focus the circularly polarized light of the first rotation direction at the second position to form a virtual image plane, wherein the virtual image plane at the first position and the virtual image plane at the second position have different focal lengths, forming virtual image planes with different focal lengths. For example, the arrangement of liquid crystal molecules in the second liquid crystal layer 223 is passively controlled to prepare the second liquid crystal layer 223. For example, the second liquid crystal layer 223 itself can have different focal lengths through the photo-alignment method and the interference exposure method, so that the second liquid crystal layer 223 has different focusing effects on the circularly polarized light of the first rotation direction and the circularly polarized light of the second rotation direction.

[0074] The second liquid crystal layer 223 is located on the light-emitting side of the first liquid crystal layer 222 . The second liquid crystal layer 223 can produce different focusing effects for circularly polarized light of different rotation directions, so as to perform focusing imaging at the human eye, improve convergence conflict, and eliminate the discomfort of the viewer.

[0075] Therefore, in the above embodiment, an optical device 100 is provided. The optical device 100 includes an optical base 1 and a first transparent substrate 2, wherein a zoom group 22 is arranged in a second region of the first transparent substrate 2 corresponding to the outcoupling region, wherein a first liquid crystal layer 222 in the zoom group 22 can switch between a first orientation and a second orientation, and the second liquid crystal layer 223 produces different focusing effects at the human eye on circularly polarized light of different rotation directions generated by the first liquid crystal layer 222, so that it is not easy for a viewer to have a convergence conflict when viewing a three-dimensional image, thereby ensuring the imaging quality. On the other hand, the zoom group 22 includes a first liquid crystal layer 222 and a second liquid crystal layer 223, which reduces the weight of the optical device, and the optical device is applied to a head-mounted display device 4, realizing a lightweight head-mounted display device 4.

[0076] In an optional embodiment, the optical machine module 10 includes a display screen and a collimated light path, which can parallelize the light projected by the display screen into the optical device.

[0077] It should be noted that the technical solution provided in the embodiments of the present application is not only applicable to optical waveguide devices, but also to various optical solutions such as free-form surfaces.

[0078] In one embodiment, the first light modulation component 21 includes a third liquid crystal layer 211 , and the third liquid crystal layer 211 is configured to convert the linearly polarized light into circularly polarized light.

[0079] In one embodiment, referring to Figure 1 The first light modulation component 21 includes a third liquid crystal layer 211 and a fourth liquid crystal layer 212, the third liquid crystal layer 211 and the fourth liquid crystal layer 212 are stacked, and the fourth liquid crystal layer 212 is arranged away from the first transparent substrate 2 relative to the third liquid crystal layer 211; the fourth liquid crystal layer 212 is configured to convert the image light projected by the display screen into linear polarized light; the third liquid crystal layer 211 is configured to convert the linear polarized light into circular polarized light.

[0080] It should be emphasized that when the image light emitted by the target display screen is linearly polarized light, the first light modulation component 21 may only include the third liquid crystal layer 211. In the above embodiment, the first light modulation component 21 includes the third liquid crystal layer 211 and the fourth liquid crystal layer 212. The first light modulation component 21 is composed of a liquid crystal layer, and the light emitted by the display screen is modulated by the liquid crystal layer. Compared with the prior art, in which the light is modulated by a wafer, the present embodiment can attach the liquid crystal layer to the first transparent substrate 2 to reduce the weight of the optical device.

[0081] Specifically, the third liquid crystal layer 211 and the fourth liquid crystal layer 212 are stacked in the first area of ​​the first transparent substrate 2. For example, the third liquid crystal layer 211 is attached to the surface of the first area of ​​the first transparent substrate 2 facing away from the optical base 1, and the fourth liquid crystal layer 212 is attached on the third liquid crystal layer 211. That is, the fourth liquid crystal layer 212 is arranged closer to the optical machine module 10 relative to the third liquid crystal layer 211.

[0082] The fourth liquid crystal layer 212 can convert the image light projected by the display screen into linear polarized light, that is, the fourth liquid crystal layer 212 can achieve the effect of a polarizer, and the third liquid crystal layer 211 can convert the linear polarized light into circular polarized light, and the third liquid crystal layer 211 can achieve the effect of a quarter wave plate. The fourth liquid crystal layer 212 converts the light emitted from the display screen into linear polarized light after passing through the fourth liquid crystal layer 212, and then into circular polarized light after passing through the third liquid crystal layer 211, and is coupled into the optical substrate 1 through the coupling region of the optical substrate 1, and is transmitted in the optical substrate 1.

[0083] It should be noted that the third liquid crystal layer 211 and the fourth liquid crystal layer 212 have different internal structures, and the liquid crystal layer can have different modulation effects on light by adjusting the pitch of the liquid crystal molecules in the liquid crystal layer. It is well known to those skilled in the art that the liquid crystal layer can have different modulation effects on light (for example, adjusting the polarization state of light) by adjusting the pitch of the liquid crystal molecules in the liquid crystal layer, and the internal structures of the third liquid crystal layer 211 and the fourth liquid crystal layer 212 are not described in detail here.

[0084] In the above embodiment, the structure of the first light modulation component 21 is limited, so that the overall weight of the optical device is reduced. The optical device is applied to the head-mounted display device 4, thereby realizing a lightweight design of the head-mounted display device 4.

[0085] In one embodiment, the first liquid crystal layer 222 is connected to an electronic control component so that the first liquid crystal layer 222 switches between the first orientation and the second orientation;

[0086] In the first orientation, the first liquid crystal layer 222 can reflect circularly polarized light of a first rotation direction and can transmit circularly polarized light of a second rotation direction;

[0087] In the second orientation, the second liquid crystal layer 223 can reflect circularly polarized light of the second rotation direction and transmit circularly polarized light of the first rotation direction.

[0088] In the above embodiment, the first liquid crystal layer 222 is connected to the electric control component, and the first liquid crystal layer 222 can be switched between the first orientation and the second orientation by, for example, controlling the voltage of the first liquid crystal layer 222, so as to allow the transmission of circularly polarized light of different rotation directions. For example, when a voltage is applied to the first liquid crystal layer 222, the first liquid crystal layer 222 is in the first orientation; when no voltage is applied to the first liquid crystal layer 222, the first liquid crystal layer 222 is in the second orientation.

[0089] For example, when the first liquid crystal layer 222 is in the first orientation, the first liquid crystal layer 222 reflects circularly polarized light of the first rotation direction and transmits circularly polarized light of the second rotation direction. For example, when the first liquid crystal layer 222 is in the right-handed state, the first liquid crystal layer 222 can reflect right-handed circularly polarized light and transmit left-handed circularly polarized light.

[0090] When the first liquid crystal layer 222 is in the second orientation, the first liquid crystal layer 222 reflects the second circularly polarized light and transmits the first circularly polarized light. For example, when the second liquid crystal layer 223 is in the left-handed state, the first liquid crystal layer 222 can reflect the left-handed circularly polarized light and transmit the right-handed circularly polarized light.

[0091] In the above embodiment, a zoom group 22 is arranged on the surface of the second area of ​​the first transparent substrate 2 away from the optical base 1. The zoom group 22 is composed of a liquid crystal layer. On the one hand, the image projected by the optical machine module 10 is zoomed through the zoom group 22 so that the image can be presented in a virtual image plane of various focal lengths, thereby further improving the convergence conflict and eliminating the discomfort of the viewer. On the other hand, the zoom group 22 is composed of a liquid crystal layer. The zoom group 22 can be attached to the first transparent substrate 2, which reduces the weight of the optical device. The optical device is applied to the head-mounted display device 4 to achieve a lightweight setting of the head-mounted display device 4.

[0092] In one embodiment, the first liquid crystal layer 222 is a cholesteric liquid crystal layer.

[0093] In the above specific embodiment, the first liquid crystal layer 222 is a cholesteric liquid crystal layer, that is, the first liquid crystal layer 222 has cholesteric liquid crystal molecules with a helical structure, and the cholesteric liquid crystal molecules with a helical structure are voltage-controlled to allow circularly polarized light of different rotation directions to pass through.

[0094] In one embodiment, the second liquid crystal layer 223 is a nematic liquid crystal layer.

[0095] In the above specific embodiment, the second liquid crystal layer 223 is a nematic liquid crystal layer, that is, the second liquid crystal layer 223 contains nematic liquid crystal molecules, which can produce different focusing effects for circularly polarized light with different rotation directions.

[0096] It should be noted that in this embodiment, the type of liquid crystal molecules in the second liquid crystal layer 223 is selected as nematic phase liquid crystal molecules. In fact, other types of liquid crystal molecules can also be selected as long as the second liquid crystal layer 223 can have different focusing effects on circularly polarized light of different rotation directions.

[0097] In one embodiment, referring to Figure 2 and Figure 3 The zoom group 22 includes three sub-zoom groups 221, and the first liquid crystal layer 222 in each sub-zoom group 221 is individually connected to an electric control component to form virtual image planes with six focal lengths.

[0098] In the above embodiment, the zoom group 22 includes three sub-zoom groups 221. The three sub-zoom groups 221 include a first sub-zoom group 221, a second sub-zoom group 221 and a third sub-zoom group 221. The first sub-zoom group 221, the second sub-zoom group 221 and the third sub-zoom group 221 are stacked and arranged in the second area of ​​the first transparent substrate 2. Therefore, in this embodiment, six focal planes are realized by the three sub-zoom groups 221, so that the zoom group 22 can switch in six different focal length ranges to achieve near eye to infinity.

[0099] For example, the first sub-zoom group 221 includes a first liquid crystal layer 222 and a second liquid crystal layer 223. The second sub-zoom group 221 includes a first liquid crystal layer 222 and a second liquid crystal layer 223. The third sub-zoom group 221 includes a first liquid crystal layer 222 and a second liquid crystal layer 223.

[0100] The second liquid crystal layer 223 in the first sub-zoom group 221, the second liquid crystal layer 223 in the second sub-zoom group 221 and the second liquid crystal layer 223 in the third sub-zoom group 221 must not be of the same design so as to focus on the same focal length position; and they must not focus on the same focal position during and after zooming.

[0101] For example, for the first sub-zoom group 221, the circularly polarized light transmitted in the optical substrate 1 first passes through the first liquid crystal layer 222 of the first sub-zoom group 221. For example, at this time, the first liquid crystal layer 222 is in the first orientation, and the first liquid crystal layer 222 allows the circularly polarized light with the opposite rotation direction to be transmitted. After the circularly polarized light is transmitted, the second liquid crystal layer 223 corresponds to the first focal length for the circularly polarized light according to the type of circularly polarized light it receives, that is, the circularly polarized light is focused to the first focal plane; if at this time, the first liquid crystal layer 222 is in the second orientation, the first liquid crystal layer 222 allows the circularly polarized light with the opposite rotation direction to be transmitted. After the circularly polarized light is transmitted, the second liquid crystal layer 223 corresponds to the second focal length for the circularly polarized light according to the type of circularly polarized light it receives, that is, the circularly polarized light is focused to the second focal plane. Therefore, in this embodiment, the first sub-zoom group 221 has two different focal lengths for circularly polarized light with different rotation directions, forming two focal planes. The focal lengths corresponding to the two focal planes are completely different.

[0102] Similarly, for the second sub-zoom group 221, the circularly polarized light transmitted from the first sub-zoom group 221 passes through the first liquid crystal layer 222 of the second sub-zoom group 221, and the orientation of the first liquid crystal layer 222 in the second sub-zoom group 221 is controlled, so that one of the circularly polarized light rotation directions can be selectively allowed to pass through. After the circularly polarized light passes through, the second liquid crystal layer 223 in the second sub-zoom group 221 corresponds to the third focal length for the circularly polarized light according to the type of circularly polarized light it receives, that is, the circularly polarized light is focused to the third focal plane; if the orientation of the first liquid crystal layer 222 in the second sub-zoom group 221 is changed at this time, the second liquid crystal layer 223 in the second sub-zoom group 221 corresponds to the fourth focal length for the circularly polarized light according to the type of circularly polarized light it receives, that is, the circularly polarized light is focused to the fourth focal plane.

[0103] Similarly, for the third sub-zoom group 221, the circularly polarized light transmitted from the second sub-zoom group 221 passes through the first liquid crystal layer 222 of the third sub-zoom group 221, and the orientation of the first liquid crystal layer 222 in the third sub-zoom group 221 is controlled, so that one of the circular polarized light rotation directions can be selectively allowed to pass through. After the circularly polarized light passes through, the second liquid crystal layer 223 in the third sub-zoom group 221 corresponds to the fifth focal length for the circularly polarized light according to the type of circularly polarized light it receives, that is, the circularly polarized light is focused to the fifth focal plane; if the orientation of the first liquid crystal layer 222 in the third sub-zoom group 221 is changed at this time, the second liquid crystal layer 223 in the third sub-zoom group 221 corresponds to the sixth focal length for the circularly polarized light according to the type of circularly polarized light it receives, that is, the circularly polarized light is focused to the sixth focal plane.

[0104] For example, the arrangement of liquid crystal molecules in the second liquid crystal layer 223 in the first sub-zoom group 221, the second liquid crystal layer 223 in the second sub-zoom group 221, and the second liquid crystal layer 223 in the third sub-zoom group 221 can be changed, the second liquid crystal layer 223 can be passively controlled, and the second liquid crystal layer 223 in the three sub-zoom groups 221 can be prepared differently (for example, by photo-controlled orientation method or interference exposure preparation), so that the second liquid crystal layer 223 in the three sub-zoom groups 221 have different focal lengths.

[0105] In this embodiment, the zoom group 22 includes three sub-zoom groups 221, each sub-zoom group 221 includes a first liquid crystal layer 222 and a second liquid crystal layer 223, and voltages are applied to the three first liquid crystal layers 222 respectively, so that the zoom group 22 can achieve zooming of six focal planes (for example, a zoom range of 0-2.5D can be achieved), thereby expanding the zoom range.

[0106] It should be noted that the present embodiment does not limit the number of sub-zoom groups 221 included in the zoom group 22 , as long as the real-time zooming of the zoom group 22 can be achieved by processing the sub-zoom groups 221 .

[0107] In one embodiment, referring to Figure 1 , the optical device further comprises a second transparent substrate 3, the second transparent substrate 3 is stacked with the optical base 1, and the first transparent substrate 2 and the second transparent substrate 3 are respectively located on two opposite sides of the optical base 1;

[0108] The second transparent substrate 3 has a third area corresponding to the outcoupling area;

[0109] A second light modulation component 31 and a zoom compensation group 32 are arranged on a side of the third region away from the optical base 1, and the zoom compensation group 32 is arranged close to the second transparent substrate 3 relative to the second light modulation component 31;

[0110] The second light modulation component 31 is configured to convert ambient light into circularly polarized light;

[0111] The zoom compensation group 32 is configured to compensate for the zoom parameters of the zoom group 22 .

[0112] In the above embodiment, the optical device further includes a second transparent substrate 3, wherein the second transparent substrate 3 and the first transparent substrate 2 are arranged on two opposite sides of the optical base 1. For example, the second transparent substrate 3 is arranged on the side away from the human eye, and the second transparent substrate 3 and the optical base 1 can be fixed by bonding, for example, by optical glue.

[0113] Generally, the ambient light on the side of the optical base 1 away from the human eye will enter the human eye through the second transparent substrate 3, the optical base 1 and the zoom group 22, that is, while the zoom group 22 zooms the circularly polarized light transmitted by the optical base 1, the ambient light on the side away from the human eye will also be zoomed accordingly, so that the light transmitted in the optical base 1 cannot be clearly presented to the human eye. For example, the composition of the ambient light is relatively complex, and more than half of the light in the ambient light is circularly polarized light. After the circularly polarized light in the ambient light passes through the optical base 1 and the zoom group 22, the circularly polarized light in the ambient light will have focal length compensation. This situation is not ideal and will cause the human eye to see the picture unclearly. That is, in this embodiment, it is only desired to zoom the projected image light in the optical machine module 10, and it is not desired to zoom the ambient light.

[0114] Therefore, in the above embodiment, the second transparent substrate 3 has a third area corresponding to the outcoupling area, and a second light modulation component 31 and a zoom compensation group 32 are arranged on a side of the third area away from the optical base 1 .

[0115] Specifically, the ambient light is converted into circularly polarized light by the second light modulating component 31. The zoom compensation group 32 compensates the zoom parameter of the zoom group 22. For example, if the zoom group 22 realizes 1D diopter adjustment, the zoom compensation group 32 needs to realize -D diopter adjustment to offset the influence of the zoom group 22 on the ambient light.

[0116] For example, the ambient light is modulated by the second light modulator 31 to become circularly polarized light, and the circularly polarized light passes through the zoom compensation group 32, the optical base 1 and the zoom group 22 to offset the influence of the optical device on the ambient light, thereby improving the clarity of the picture viewed by the human eye.

[0117] In one embodiment, the zoom compensation group 32 includes at least one sub-zoom compensation group 321, and the sub-zoom compensation group 321 includes a fifth liquid crystal layer 322 and a sixth liquid crystal layer 323, and the sixth liquid crystal layer 323 is arranged relative to the fifth liquid crystal layer 322 and close to the second transparent substrate 3;

[0118] The fifth liquid crystal layer 322 is configured to switch between a first orientation and a second orientation to project circularly polarized light of different rotation directions to the sixth liquid crystal layer 323; the sixth liquid crystal layer 323 receives the circularly polarized light and transmits the circularly polarized light to the zoom group 22, wherein the optical focal length of the sixth liquid crystal layer 323 is opposite to the optical focal length of the second liquid crystal layer 223 to compensate for the zoom parameter of the zoom group 22.

[0119] In the above embodiment, the zoom compensation group 32 includes the fifth liquid crystal layer 322 and the sixth liquid crystal layer 323, wherein the sixth liquid crystal layer 323 can be attached to the surface of the second transparent substrate 3, and the fifth liquid crystal layer 322 can be attached to the sixth liquid crystal layer 323. Alternatively, the fifth liquid crystal layer 322 and the sixth liquid crystal layer 323 are compounded into a compound film, and the compound film is attached to the second transparent substrate 3.

[0120] In the above embodiment, the fifth liquid crystal layer 322 can switch between the first orientation and the second orientation. The function of the fifth liquid crystal layer 322 is the same as that of the first liquid crystal layer 222 discussed above, which is to selectively allow circularly polarized light of one rotation direction to pass through. Therefore, in this embodiment, the fifth liquid crystal layer 322 is not described in detail.

[0121] In the above embodiment, after the sixth liquid crystal layer 323 receives circularly polarized light of different rotation directions, it transmits the corresponding circularly polarized light through the optical substrate 1, the first liquid crystal layer 222 and the second liquid crystal layer 223. Since the optical focal lengths of the sixth liquid crystal layer 323 and the second liquid crystal layer 223 are opposite, the circularly polarized light of different rotation directions passes through the sixth liquid crystal layer 323 and the second liquid crystal layer 223 in sequence, which is equivalent to passing through flat glass. The human eye, at its focused position, can view the virtual image magnified and projected by the zoom group 22 and the scene in the environment, thereby realizing AR display.

[0122] In one embodiment, the second optical adjustment component includes a seventh liquid crystal layer 311 and an eighth liquid crystal layer 312, the seventh liquid crystal layer 311 and the eighth liquid crystal layer 312 are stacked, and the seventh liquid crystal layer 311 is arranged away from the second transparent substrate 3 relative to the eighth liquid crystal layer 312;

[0123] The seventh liquid crystal layer 311 is configured to convert ambient light into linearly polarized light;

[0124] The eighth liquid crystal layer 312 is configured to convert the linearly polarized light into circularly polarized light.

[0125] In the above embodiment, the second light modulating component 31 is composed of a liquid crystal layer, and the ambient light is modulated by the liquid crystal layer. Compared with the prior art, in which light is modulated by a wafer, the liquid crystal layer can be attached to the second transparent substrate 3 in this embodiment to reduce the weight of the optical device.

[0126] Specifically, the seventh liquid crystal layer 311 and the eighth liquid crystal layer 312 are stacked and disposed in the third region of the second transparent substrate 3 .

[0127] The seventh liquid crystal layer 311 can convert ambient light into linearly polarized light, that is, the seventh liquid crystal layer 311 can achieve the effect of a polarizer, and the eighth liquid crystal layer 312 can convert linearly polarized light into circularly polarized light, that is, the eighth liquid crystal layer 312 can achieve the effect of a quarter wave plate.

[0128] It should be noted that the seventh liquid crystal layer 311 and the eighth liquid crystal layer 312 have different internal structures, and the liquid crystal layer can have different modulation effects on light by adjusting the pitch (Pitch) of the liquid crystal molecules in the liquid crystal layer. It is well known to those skilled in the art that the liquid crystal layer has different modulation effects on light (for example, adjusting the polarization state of light) by adjusting the pitch (Pitch) of the liquid crystal molecules in the liquid crystal layer, and the internal structures of the seventh liquid crystal layer 311 and the eighth liquid crystal layer 312 are not described in detail here.

[0129] In the above embodiment, the structure of the second light modulation component 31 is limited, so that the overall weight of the optical device is reduced. The optical device is applied to the head-mounted display device 4, thereby realizing a lightweight design of the head-mounted display device 4.

[0130] In one embodiment, the zoom compensation group 32 includes three groups of sub-zoom compensation groups 321, the fifth liquid crystal layer 322 in each sub-zoom compensation group 321 is individually connected to an electric control component, and the optical focal length of the sixth liquid crystal layer 323 in each sub-zoom compensation group 321 is opposite to the optical focal length of the corresponding second liquid crystal layer 223.

[0131] In the above embodiment, the zoom compensation group 32 and the zoom group 22 are mirror-symmetrical with respect to the optical base 1 in structure.

[0132] In the above embodiment, the zoom compensation group 32 includes three sub-zoom compensation groups 321. The three sub-zoom compensation groups 321 include a first sub-zoom compensation group 321, a second sub-zoom compensation group 321 and a third sub-zoom compensation group 321. The first sub-zoom compensation group 321, the second sub-zoom compensation group 321 and the third sub-zoom compensation group 321 are stacked on the third area of ​​the second transparent substrate 3. The first sub-zoom compensation group 321 corresponds to the first sub-zoom group 221 in position, the second sub-zoom compensation group 321 corresponds to the second sub-zoom group 221 in position, and the third sub-zoom compensation group 321 corresponds to the third sub-zoom group 221 in position. The zoom compensation group 32 and the zoom group 22 have opposite optical powers.

[0133] For example, the first sub-zoom compensation group 321 includes a fifth liquid crystal layer 322 and a sixth liquid crystal layer 323, wherein the sixth liquid crystal layer 323 corresponds to the second liquid crystal layer 223 in the first sub-zoom group 221, and the two have opposite optical focal lengths. For example, the second liquid crystal layer 223 corresponds to two focal lengths, and the sixth liquid crystal layer 323 corresponds to two focal lengths. The focal lengths of the two liquid crystal layers are related, so that the fifth liquid crystal layer 322 and the sixth liquid crystal layer 323 have opposite optical focal lengths. The second sub-zoom compensation group 321 includes a fifth liquid crystal layer 322 and a sixth liquid crystal layer 323, wherein the sixth liquid crystal layer 323 corresponds to the second liquid crystal layer 223 in the second sub-zoom group 221, and the two have opposite optical focal lengths. The third sub-zoom compensation group 321 includes a fifth liquid crystal layer 322 and a sixth liquid crystal layer 323, wherein the sixth liquid crystal layer 323 corresponds to the second liquid crystal layer 223 in the fourth zoom group 22, and the two have opposite optical focal lengths.

[0134] In the above embodiment, the structures of the zoom compensation group 32 and the zoom group 22 are limited so that the zoom group 22 on the side of the waveguide plate close to the human eye can achieve positive refractive power (for example, 5D optical focal length) adjustment, and the zoom compensation group 32 on the outer side of the waveguide plate can achieve -5D refractive power adjustment to offset the influence of the optical device on ambient light.

[0135] According to the optical device 100 provided in the embodiment of the present application, the optical substrate 1 therein may be a waveguide substrate, or may be other substrates or optical devices, and the present application does not impose any limitation on this.

[0136] In a second aspect, a head mounted display device 4 is provided. The head mounted display device 4 comprises:

[0137] a housing; and

[0138] As described in the first aspect, the optical device is arranged on the housing.

[0139] In some examples of the present application, the head mounted device may be augmented reality smart glasses, etc. The specific implementation of the head mounted device in the embodiment of the present application may refer to the above-mentioned embodiments of the optical device, which will not be described in detail here.

[0140] In a third aspect, a method for adjusting a head mounted display device 4 is provided. The method comprises the following steps S01 to S03:

[0141] S01: Acquire human eye information data;

[0142] S02: Determine the human eye focus position information according to the human eye information data;

[0143] S03: adjusting the orientation of the first liquid crystal layer 222 according to the human eye focus position information, so that the optical device can achieve zooming.

[0144] In this embodiment, for example, the head mounted display device 4 may be an augmented reality smart glasses. The smart glasses include two frames 41, and one of the above-mentioned optical devices is arranged on each frame 41.

[0145] In the above step S01, human eye information data is obtained, for example, two eye trackers 42 are set on the smart glasses. When the human eye looks at different objects, the distance between the two pupils and the size of the pupils will change. By setting two eye trackers 42 on the smart glasses (the eye trackers 42 are set next to the nose pads), the distance between the two pupils, the size of the pupils, and the direction the eyes are looking can be identified. That is, the human eye information data includes the distance between the two pupils, the size of the pupils, and the direction the eyes are looking.

[0146] Of course, there are many ways to obtain human eye information data, including but not limited to the above description.

[0147] In the above step S02, the human eye information data obtained by the eye tracker 42 is sent to the built-in processing unit for calculation to obtain the current eye focus position, and the position information is converted into a control signal, thereby determining the position information of the human eye focus.

[0148] In the above step S03, after obtaining the position information of the human eye focus, the focal length of the zoom group 22 can be adjusted according to the virtual image plane corresponding to the position information of the human eye focus, thereby bringing a more realistic and immersive visual experience to the viewer.

[0149] Specifically, the focusing position information of the human eye is transmitted to the electronic control component, which applies voltage to the first liquid crystal layer 222, selectively allowing one kind of circularly polarized light to pass through, and then the second liquid crystal layer 223 projects the circularly polarized light onto a virtual image plane according to the type of circularly polarized light, thereby realizing the zoom of the optical device.

[0150] The above embodiments focus on the differences between the various embodiments. As long as the different optimization features between the various embodiments are not contradictory, they can be combined to form a better embodiment. Considering the simplicity of the text, they will not be repeated here.

[0151] Although some specific embodiments of the present invention have been described in detail by way of example, it will be appreciated by those skilled in the art that the above examples are for illustration only and are not intended to limit the scope of the present invention. It will be appreciated by those skilled in the art that the above embodiments may be modified without departing from the scope and spirit of the present invention. The scope of the present invention is defined by the appended claims.

Claims

1. An optical device, characterized in that: The optical device comprises an optical substrate (1) and a first transparent substrate (2), wherein the optical substrate (1) and the first transparent substrate (2) are stacked; The optical base (1) has a coupling-in region and a coupling-out region, and the first transparent substrate (2) has a first region corresponding to the coupling-in region, and a second region corresponding to the coupling-out region; A first light modulation component (21) is arranged on a side of the first transparent substrate (2) facing away from the optical base (1) and in the first region, and the first light modulation component (21) is configured to be able to convert image light projected by a target display screen into circularly polarized light; A zoom group (22) is arranged on a side of the first transparent substrate (2) away from the optical base (1), and in the second region, the zoom group (22) comprises at least one sub-zoom group (221), the sub-zoom group (221) comprises a first liquid crystal layer (222) and a second liquid crystal layer (223), the second liquid crystal layer (223) being arranged away from the first transparent substrate (2) relative to the first liquid crystal layer (222); The first liquid crystal layer (222) is configured to switch between a first orientation and a second orientation so as to transmit circularly polarized light of different rotation directions to the second liquid crystal layer (223); the second liquid crystal layer (223) forms virtual image planes of at least two focal lengths according to the received circularly polarized light of different rotation directions.

2. The optical device according to claim 1, characterized in that The first light modulation component (21) comprises a third liquid crystal layer (211), and the third liquid crystal layer (211) is configured to convert linearly polarized light into circularly polarized light.

3. The optical device according to claim 2, characterized in that: The first light modulation component (21) further comprises a fourth liquid crystal layer (212), the third liquid crystal layer (211) and the fourth liquid crystal layer (212) are stacked, and the fourth liquid crystal layer (212) is arranged away from the first transparent substrate (2) relative to the third liquid crystal layer (211); The fourth liquid crystal layer (212) is configured to convert image light projected by the display screen into linearly polarized light.

4. The optical device according to claim 1, characterized in that The first liquid crystal layer (222) is connected to an electric control component, so that the first liquid crystal layer (222) switches between a first orientation and a second orientation; In the first orientation, the first liquid crystal layer (222) is capable of reflecting circularly polarized light of a first rotation direction and transmitting circularly polarized light of a second rotation direction; In the second orientation, the first liquid crystal layer (222) can reflect circularly polarized light of the second rotation direction and can transmit circularly polarized light of the first rotation direction.

5. The optical device according to claim 1, characterized in that: The first liquid crystal layer (222) is a cholesteric liquid crystal layer.

6. The optical device according to claim 1, characterized in that: The second liquid crystal layer (223) is a nematic liquid crystal layer.

7. The optical device according to claim 1, characterized in that: The zoom group (22) comprises three sub-zoom groups (221), and the first liquid crystal layer (222) in each sub-zoom group (221) is individually connected to an electric control component to form virtual image planes of six focal lengths.

8. The optical device according to claim 1, characterized in that: The optical device further comprises a second transparent substrate (3), wherein the second transparent substrate (3) is stacked with the optical base (1), and the first transparent substrate (2) and the second transparent substrate (3) are respectively located on two opposite sides of the optical base (1); The second transparent substrate (3) has a third area corresponding to the outcoupling area; A second light modulation component (31) and a zoom compensation group (32) are arranged on a side of the third region away from the optical base (1); the zoom compensation group (32) is arranged close to the second transparent substrate (3) relative to the second light modulation component (31); The second light modulation component (31) is configured to convert ambient light into circularly polarized light; The zoom compensation group (32) is configured to compensate for the zoom parameters of the zoom group (22).

9. The optical device according to claim 8, characterized in that: The zoom compensation group (32) comprises at least one sub-zoom compensation group (321), the sub-zoom compensation group (321) comprises a fifth liquid crystal layer (322) and a sixth liquid crystal layer (323), the sixth liquid crystal layer (323) being arranged relative to the fifth liquid crystal layer (322) and close to the second transparent substrate (3); The fifth liquid crystal layer (322) is configured to switch between a first orientation and a second orientation to project circularly polarized light of different rotation directions to the sixth liquid crystal layer (323); the sixth liquid crystal layer (323) receives the circularly polarized light and transmits the circularly polarized light to the zoom group (22), wherein the optical focal length of the sixth liquid crystal layer (323) is opposite to the optical focal length of the second liquid crystal layer (223) to compensate for the zoom parameter of the zoom group (22).

10. The optical device according to claim 8, characterized in that The second light modulation component (31) comprises a seventh liquid crystal layer (311) and an eighth liquid crystal layer (312), the seventh liquid crystal layer (311) and the eighth liquid crystal layer (312) being stacked, and the seventh liquid crystal layer (311) is arranged away from the second transparent substrate (3) relative to the eighth liquid crystal layer (312); The seventh liquid crystal layer (311) is configured to convert ambient light into linearly polarized light; The eighth liquid crystal layer (312) is configured to convert the linearly polarized light into circularly polarized light.

11. The optical device according to claim 9, characterized in that: The zoom compensation group (32) comprises three groups of sub-zoom compensation groups (321), the fifth liquid crystal layer (322) in each group of sub-zoom compensation groups (321) is individually connected to an electric control component, and the optical focal length of the sixth liquid crystal layer (323) in each group of sub-zoom compensation groups (321) is opposite to the optical focal length of the corresponding second liquid crystal layer (223).

12. A head mounted display device, characterized in that: include: An optical device as claimed in any one of claims 1 to 11.

13. A method for adjusting a head mounted display device as claimed in claim 12, characterized in that: The adjustment method comprises: Obtain human eye information data; Determine the human eye focusing position information according to the human eye information data; The orientation of the first liquid crystal layer (222) is adjusted according to the human eye focus position information, and the second liquid crystal layer (223) forms virtual image planes of at least two focal lengths according to the received circularly polarized light of different rotation directions, so that the optical device can achieve zooming.

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