Near-eye display device and control method

Abstract

Provided in the present disclosure are a near-eye display device and a control method. The near-eye display device comprises: a display assembly for emitting a linearly polarized light; and a zoom assembly located on an exit light path of the display assembly and comprising a first liquid crystal polarization rotator and a liquid crystal lens, wherein the first liquid crystal polarization rotator is configured to switch and emit the incident linearly polarized light between a first linearly polarized light and a second linearly polarized light, the first linearly polarized light having a phase difference of 0 with respect to the incident linearly polarized light, and the second linearly polarized light having a phase difference of π with respect to the incident linearly polarized light; and the liquid crystal lens is located on an exit light path of the first liquid crystal polarization rotator, and is configured to focus the first linearly polarized light or the second linearly polarized light emitted from the first liquid crystal polarization rotator at different focal lengths.

Description

Near-eye display device and control method Technical Field

[0001] This disclosure relates to the field of near-eye display technology, and more particularly to a near-eye display device and control method. Background Technology

[0002] Near-eye display technology is a technology that creates virtual scenes in front of a person's eyes using display devices located at a distance from the human eye that is not within the visible range of human vision. It includes types such as Augmented Reality (AR), Virtual Reality (VR), and Mixed Reality (MR).

[0003] Normally, when the human eye views an object in a display environment, its convergence and focusing functions coordinate with each other. Convergence focuses the eyes' gaze on the same object, while focusing focuses on that object at the same distance. However, in near-eye display devices, to provide an immersive experience, the displayed image on the display element presents a certain depth, but the actual distance between the display element and the human eye remains constant. Therefore, when the human eye attempts to focus on a virtual object at different depths, the eye's line of sight differs from the focal point. This creates a conflict between the convergence and focusing functions, known as convergence-accommodation conflict. The existence of convergence-accommodation conflict forces the brain to synthesize information that the line of sight and the focal point are not in the same position. Over time, this can lead to adverse reactions such as visual fatigue, dizziness, and headaches, affecting the user experience.

[0004] Summary of the Invention

[0005] This disclosure provides a near-eye display device and control method for eliminating convergence-accommodation conflict.

[0006] In a first aspect, this disclosure provides a near-eye display device, comprising: a display component for emitting X-ray polarized light;

[0007] A zoom component is located in the light-emitting path of the display component; the zoom component includes:

[0008] A first liquid crystal polarization rotator is used to switch incident linearly polarized light between a first linearly polarized light and a second linearly polarized light for output, wherein the phase difference between the first linearly polarized light and the incident linearly polarized light is 0, and the phase difference between the second linearly polarized light and the incident linearly polarized light is π.

[0009] A liquid crystal lens is located in the light output path of the first liquid crystal polarization rotator; the liquid crystal lens is used to focus the first linearly polarized light or the second linearly polarized light emitted from the first liquid crystal polarization rotator onto different focal lengths.

[0010] In some embodiments of this disclosure, there are multiple zoom components, which are arranged sequentially along the light emission path of the display component.

[0011] In some embodiments of this disclosure, the near-eye display device further includes an imaging lens group located between the display component and the zoom component, or the imaging lens group is located on the light-emitting side of the zoom component.

[0012] In some embodiments of this disclosure, the near-eye display device further includes an imaging lens group located between the display component and the plurality of zoom components, or the imaging lens group is located in the light output path of the plurality of zoom components, or the imaging lens group is located between any two of the plurality of zoom components.

[0013] In some embodiments of this disclosure, the imaging lens group includes at least one imaging lens.

[0014] In some embodiments of this disclosure, the near-eye display device further includes a first phase retardation layer and an optical path refracting assembly, wherein the first phase retardation layer is located between the display assembly and the optical path refracting assembly; the first phase retardation layer is used to delay the phase of incident linearly polarized light by π / 2 to convert it into circularly polarized light for emission; the optical path refracting assembly is used to reflect the circularly polarized light multiple times and convert it into linearly polarized light for emission.

[0015] In some embodiments of this disclosure, the zoom component is located on the light output path of the optical path refraction component.

[0016] In some embodiments of this disclosure, the zoom component is located between the display component and the first phase retardation layer; the near-eye display device further includes a second liquid crystal polarization rotator, which is located between the zoom component and the first phase retardation layer.

[0017] In some embodiments of this disclosure, the optical path reversal assembly includes a partially reflective and partially transmissive layer, a second phase retardation layer, and a reflective polarizer arranged sequentially away from the first phase retardation layer. The second phase retardation layer is used to delay the phase of the incident light by π / 2, and the reflective polarizer is used to reflect the first linearly polarized light and transmit the second linearly polarized light.

[0018] In some embodiments of this disclosure, the first liquid crystal polarization rotator includes at least one first liquid crystal layer, and in the first liquid crystal polarization rotator, electrode layers are disposed on both sides of each first liquid crystal layer.

[0019] In some embodiments of this disclosure, at least two adjacent first liquid crystal layers share the same electrode layer.

[0020] In some embodiments of this disclosure, the first liquid crystal layer is one of an electrically controlled birefringent liquid crystal, a vertically aligned liquid crystal, or an optically compensated bending liquid crystal.

[0021] In some embodiments of this disclosure, the liquid crystal lens includes a second liquid crystal layer, the second liquid crystal layer including a light-incident surface and a light-exiting surface, wherein the light-incident surface and / or the light-exiting surface is a curved surface.

[0022] In some embodiments of this disclosure, the liquid crystal lens further includes: a first substrate, a second substrate, a first alignment layer, and a second alignment layer. The first substrate and the second substrate are disposed opposite to each other. The first alignment layer is located on the surface of the first substrate facing the second substrate, and the second alignment layer is located on the surface of the second substrate facing the first substrate. The surface where the first alignment layer and / or the second alignment layer are located is curved. The second liquid crystal layer is located between the first alignment layer and the second alignment layer.

[0023] In some embodiments of this disclosure, the surface is aspherical.

[0024] Secondly, this disclosure also provides a control method for a near-eye display device, comprising: controlling the emitted light from a first liquid crystal polarization rotator to switch between a first linearly polarized light and a second linearly polarized light according to depth information of an image to be displayed by the display component; wherein the phase difference between the first linearly polarized light and the linearly polarized light incident on the first liquid crystal polarization rotator is 0, and the phase difference between the second linearly polarized light and the linearly polarized light incident on the first liquid crystal polarization rotator is π.

[0025] In some embodiments of this disclosure, controlling the switching of the emitted light from the first liquid crystal polarization rotator between first linearly polarized light and second linearly polarized light based on the depth information of the image to be displayed by the display component includes:

[0026] When the depth information of the displayed image is less than or equal to a preset threshold, the first liquid crystal polarization rotator is controlled to emit the first linearly polarized light.

[0027] When the depth information of the displayed image is greater than the preset threshold, the first liquid crystal polarization rotator is controlled to emit the second linearly polarized light.

[0028] In some embodiments of this disclosure, the control method further includes:

[0029] The display component is controlled to display images with the same image but different brightness in two consecutive frames, while the first liquid crystal polarization rotator is controlled to emit the first linearly polarized light and the second linearly polarized light in the two consecutive frames respectively. Attached Figure Description

[0030] Figure 1 is a schematic diagram of a near-eye display device provided in an embodiment of this disclosure;

[0031] Figure 2 is a schematic diagram of the zoom component provided in the embodiment of this disclosure;

[0032] Figure 3 is a schematic diagram of one of the control methods provided in the embodiments of this disclosure;

[0033] Figure 4 is a schematic diagram of the control method provided in the embodiment of this disclosure;

[0034] Figure 5 is a structural schematic diagram of another near-eye display device provided in an embodiment of this disclosure;

[0035] Figure 6 is a structural schematic diagram of another near-eye display device provided in an embodiment of this disclosure;

[0036] Figure 7 is a schematic diagram of another near-eye display device provided in an embodiment of this disclosure;

[0037] Figure 8 is a structural schematic diagram of another near-eye display device provided in an embodiment of this disclosure;

[0038] Figure 9 is a structural schematic diagram of another near-eye display device provided in an embodiment of this disclosure;

[0039] Figure 10 is a structural schematic diagram of another near-eye display device provided in an embodiment of this disclosure;

[0040] Figure 11 is a schematic diagram of another near-eye display device provided in an embodiment of this disclosure;

[0041] Figure 12 is a schematic diagram of another near-eye display device provided in an embodiment of this disclosure;

[0042] Figure 13 is a schematic diagram of a first liquid crystal polarization rotator provided in an embodiment of this disclosure;

[0043] Figure 14 is a graph showing the dispersion characteristics of the first liquid crystal polarization rotator corresponding to Figure 13.

[0044] Figure 15 is a structural schematic diagram of another first liquid crystal polarization rotator provided in an embodiment of the present disclosure;

[0045] Figure 16 is a graph showing the dispersion characteristics of the first liquid crystal polarization rotator corresponding to Figure 15.

[0046] Figure 17 is a schematic diagram of the structure of a liquid crystal lens provided in an embodiment of this disclosure;

[0047] Figure 18 is a schematic diagram of another liquid crystal lens provided in an embodiment of this disclosure;

[0048] Figure 19 is a schematic diagram of the manufacturing process of a liquid crystal lens provided in an embodiment of this disclosure;

[0049] Figure 20 is a schematic diagram of the manufacturing process of another liquid crystal lens provided in the embodiments of this disclosure.

[0050] Reference numerals: Display component 1, display panel 11, first linear polarizer 12, zoom component 2, first liquid crystal polarization rotator 21, liquid crystal lens 22, first linearly polarized light L1, second linearly polarized light L2, first focal length f1, second focal length f2, first focal plane F1, second focal plane F2, first depth-of-field plane P1, second depth-of-field plane P2, third depth-of-field plane P, first zoom component 201, second zoom component 202, imaging lens group 3, first phase retardation layer 4, optical path refraction component 5, etc. The structure includes a transmissive layer 51 for the reflective portion, a second phase retardation layer 52, a reflective polarizer 53, a second linear polarizer 54, a first circularly polarized light C1, a second circularly polarized light C2, a second liquid crystal polarization rotator 6, a first liquid crystal layer 211, an alignment layer 212, an electrode layer 213, a substrate 214, an incident light surface 2201, an exit light surface 2202, a second liquid crystal layer 221, a first substrate 222, a second substrate 223, a first alignment layer 224, a second alignment layer 225, and a pad / shim T. Detailed Implementation

[0051] To make the objectives, technical solutions, and advantages of the embodiments of this disclosure clearer, the technical solutions of the embodiments of this disclosure will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of this disclosure. Furthermore, the embodiments and features in the embodiments of this disclosure can be combined with each other without conflict. All other embodiments obtained by those skilled in the art based on the described embodiments of this disclosure without creative effort are within the scope of protection of this disclosure.

[0052] Unless otherwise defined, the technical or scientific terms used in this disclosure shall have the ordinary meaning understood by one of ordinary skill in the art to which this disclosure pertains. The terms "first," "second," and similar terms used in this disclosure do not indicate any order, quantity, or importance, but are merely used to distinguish different components.

[0053] It should be noted that the dimensions and shapes of the figures in the accompanying drawings do not reflect actual proportions and are intended only to illustrate the content of this application. Furthermore, the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout.

[0054] Figure 1 is a schematic diagram of the structure of a near-eye display device provided in an embodiment of this disclosure.

[0055] As shown in Figure 1, the near-eye display device provided in this embodiment includes a display component 1 and a zoom component 2, with the zoom component 2 located in the light output path of the display component 1.

[0056] The display component 1 is used to emit linearly polarized light. Specifically, the display component 1 may include a display panel 11 and a first linear polarizer 12. The first linear polarizer 12 is disposed between the display panel 11 and the zoom component 2. For example, the first linear polarizer 12 can be attached to the light-emitting surface of the display. The type of the display panel 11 includes, but is not limited to, one of the following: a Mini-LED display panel, a Mini LED display panel, a Micro LED display panel, an Organic Light Emitting Diode (OLED) display panel, and a Micro OLED display panel.

[0057] The zoom assembly 2 includes a first liquid crystal polarization rotator 21 and a liquid crystal lens 22. The first liquid crystal polarization rotator 21 is used to switch the incident linearly polarized light between a first linearly polarized light and a second linearly polarized light for emission. The phase difference between the first linearly polarized light and the incident linearly polarized light is 0, and the phase difference between the second linearly polarized light and the incident linearly polarized light is π. For example, the first linearly polarized light is P-light and the second linearly polarized light is S-light, or the first linearly polarized light is S-light and the second linearly polarized light is P-light.

[0058] The liquid crystal lens 22 is located in the light output path of the first liquid crystal polarization rotator 21 and can be used to focus the first linearly polarized light or the second linearly polarized light emitted from the first liquid crystal polarization rotator 21 onto different focal lengths, that is, to form images on different focal planes.

[0059] Figure 2 is a schematic diagram of the zoom component provided in an embodiment of this disclosure.

[0060] As shown in Figure 2(a), when no voltage is applied to the first liquid crystal polarization rotator 21, the linearly polarized light incident on the first liquid crystal polarization rotator 21 still exits as the first linearly polarized light L1. The polarization direction of the first linearly polarized light L1 is the same as the polarization direction of the linearly polarized light incident on the first liquid crystal polarization rotator 21. After passing through the liquid crystal lens 22, the first linearly polarized light L1 can be focused on the first focal plane F1 at the first focal length f1.

[0061] As shown in Figure 2(b), when a voltage is applied to the first liquid crystal polarization rotator 21, the liquid crystal molecules in the first liquid crystal polarization rotator 21 are deflected. By applying a suitable voltage, the first liquid crystal polarization rotator 21 can function as a half-wave plate, delaying the phase of the linearly polarized light incident therein by π, thereby converting it into second linearly polarized light L2 for emission. Since the liquid crystal material is anisotropic, the refractive index is different for linearly polarized light with different polarization directions. Therefore, the second linearly polarized light L2 can be focused by the liquid crystal onto the second focal plane F2 at the second focal length f2. The second focal length f2 is different from the first focal length f1 mentioned above. For example, the second focal length f2 can be greater than the first focal length f1.

[0062] Based on the above zoom principle, by applying a voltage signal to control the first liquid crystal polarization rotator 21, the linearly polarized light incident on the first liquid crystal polarization rotator 21 can switch between the first linearly polarized light L1 and the second linearly polarized light L2. In conjunction with the liquid crystal lens 22, the zoom assembly 2 can focus the incident linearly polarized light onto two different focal planes.

[0063] It is understandable that the polarization direction of the first linearly polarized light L1 and the second linearly polarized light L2 is determined by the polarization direction of the linearly polarized light emitted from the display component 1. By changing the type of the first linear polarizer 12 in the display component 1, that is, changing the polarization direction of the linearly polarized light that it can transmit, the polarization direction of the linearly polarized light incident on the first liquid crystal polarization rotator 21 can be changed. Swapping the polarization directions of the first linearly polarized light L1 and the second linearly polarized light L2 has no effect on its zoom principle.

[0064] Based on the same concept, this disclosure also provides a control method for a near-eye display device. The control method includes: controlling the outgoing light of the first liquid crystal polarization rotator 21 to switch between a first linearly polarized light L1 and a second linearly polarized light L2 according to the depth information of the image to be displayed by the display component 1, thereby realizing the image to be imaged on different focal planes.

[0065] Specifically, this control method controls the first liquid crystal polarization rotator 21 to emit first linearly polarized light L1 when the depth information of the displayed image is less than or equal to a preset threshold. This allows the displayed image to be imaged on a relatively close focal plane when the image is close. Conversely, when the depth information of the displayed image is greater than the preset threshold, the first liquid crystal polarization rotator 21 is controlled to emit second linearly polarized light L2. This allows the displayed image to be imaged on a relatively distant focal plane when the image is far away. Based on this, when using a near-eye display device, the position of the displayed image observed by the human eye—that is, the focal position of the human eye—can match the line of sight, thereby alleviating adverse reactions such as visual fatigue, dizziness, and headaches caused by convergence-accommodation conflict and improving the user experience.

[0066] In some embodiments of this disclosure, the control method further includes: controlling the display component 1 to display images with the same image but different brightness in two consecutive frames, while controlling the first liquid crystal polarization rotator 21 to emit first linearly polarized light L1 and second linearly polarized light L2 in two consecutive frames, thereby enabling the displayed image to be imaged on a set depth plane.

[0067] Figure 3 is one of the schematic diagrams of the control method provided in the embodiments of this disclosure.

[0068] For ease of description, the two consecutive display frames are referred to as the first display frame and the second display frame. The light rays constituting the first and second display frames are incident on the first liquid crystal polarization rotator 21, as shown in Figure 3. When the light rays constituting the first display frame are controlled to exit in the form of first polarized light after passing through the first liquid crystal polarization rotator 21, the first display frame should be imaged on the first depth plane P1, and the distance between the formed virtual image and the human eye is Z1. When the light rays constituting the second display frame are controlled to exit in the form of second polarized light after passing through the first liquid crystal polarization rotator 21, the second display frame should be imaged on the second depth plane P2, and the distance between the formed virtual image and the human eye is Z2. By adjusting the brightness ratio of the first and second display frames, based on the persistence of vision effect of the human eye, the image observed by the human eye is a composite image of the first and second display frames, and the image observed by the human eye is located on the third depth plane P between the first depth plane P1 and the second depth plane P2.

[0069] For example, when the brightness of the first display screen is 100% and the brightness of the second display screen is 0, the brightness ratio of the first display screen and the second display screen is 1, and the image observed by the human eye is located on the first depth plane P1; when the brightness of the first display screen is 0 and the brightness of the second display screen is 100%, the brightness ratio of the first display screen and the second display screen is 0, and the image observed by the human eye is located on the first depth plane P1; when the brightness of the first display screen is 50% and the brightness of the second display screen is 50%, the brightness ratio of the first display screen and the second display screen is 0.5, and the image observed by the human eye is located on the third depth plane P.

[0070] Figure 4 is a schematic diagram of the control method provided in the embodiments of this disclosure.

[0071] Figure 4 shows the relationship between the position of the third depth-of-field plane P and the first and second display images when they have different brightness ratios. The horizontal axis represents the intensity ratio, and the vertical axis represents the accommodation distance, which reflects the position of the third depth-of-field plane P in reciprocal units. The four broken lines represent single-frequency signal images with display values ​​of 4 cpd, 9 cpd, and 21 cpd, and composite frequency signal images with display values ​​of 0-30 cpd, respectively. As shown in Figure 4, even if the first and second display images have the same brightness ratio, the position of the third depth-of-field plane P will differ when the display images are of different frequencies. Therefore, for display images dominated by different frequencies, the brightness ratio of the first and second display images needs to be adjusted according to the actual situation.

[0072] Figure 5 is a schematic diagram of another near-eye display device provided in an embodiment of this disclosure.

[0073] As shown in Figure 5, the near-eye display device may include two zoom components, which are arranged sequentially along the light output path of the display component 1. For ease of description, the two zoom components 2 are referred to as the first zoom component 201 and the second zoom component 202, respectively. The light emitted from the display component 1 is focused by the first zoom component 201 and then focused by the second zoom component 202 before being emitted. The final image position can be one of the following:

[0074] (1) When the first liquid crystal polarization rotator 21a in the first zoom assembly 201 emits first linearly polarized light and the first liquid crystal polarization rotator 21b in the second zoom assembly 202 emits first linearly polarized light, the liquid crystal lens 22a in the first zoom assembly 201 first images the linearly polarized light emitted from the display assembly 1 at a first focal length f1, and the image at the first focal length f1 is then used as the object image and is imaged by the liquid crystal lens 22b in the second zoom assembly 202 at a first focal length f1; (2) When the first liquid crystal polarization rotator 21a in the first zoom assembly 201 emits first linearly polarized light and the first liquid crystal polarization rotator 21b in the second zoom assembly 202 emits second linearly polarized light, the liquid crystal lens 22a in the first zoom assembly 201 first images the linearly polarized light emitted from the display assembly 1 at a first focal length f1, and the image at the first focal length f1 is then used as the object image and is imaged by the liquid crystal lens 22b in the second zoom assembly 202 at a second focal length f2; (3) When the first liquid crystal polarization rotator 21a in the first zoom assembly 201 emits second linearly polarized light and the first liquid crystal polarization rotator 21b in the second zoom assembly 202 emits first linearly polarized light, the liquid crystal lens 22a in the first zoom assembly 201 first images the linearly polarized light emitted from the display assembly 1 at a second focal length f2, and the image at the second focal length f2 is then used as the object image and is imaged by the liquid crystal lens 22b in the second zoom assembly 202 at a first focal length f1; (4) When the first liquid crystal polarization rotator 21a in the first zoom assembly 201 emits second linearly polarized light and the first liquid crystal polarization rotator 21b in the second zoom assembly 202 emits second linearly polarized light, the liquid crystal lens 22a in the first zoom assembly 201 first images the linearly polarized light emitted from the display assembly 1 at a second focal length f2, and the image at the second focal length f2 is then used as the object image and is imaged by the liquid crystal lens 22b in the second zoom assembly 202 at a second focal length f2.

[0075] As can be seen, the focal plane of the final image is different in the above four situations. In this embodiment of the present disclosure, by setting two zoom components 2, the image can be switched between 2 to 4 focal planes, thereby expanding the focusing range of the human eye.

[0076] In this embodiment, there may be multiple zoom components 2, arranged sequentially along the light-emitting path of the display component 1. The zoom principle of the near-eye display device shown in Figures 2 and 5 can be deduced by analogy. Each zoom component 2 can switch the image between two focal planes, thus multiple zoom components 2 can achieve image switching between two focal planes. n The switching between multiple focal planes, where n is the number of zoom components 2. By setting multiple zoom components 2 in the near-eye display device, the image can be switched between more focal planes through the cooperation of multiple zoom components 2, providing greater freedom for the human eye's focusing range and further alleviating problems such as visual fatigue caused by convergence-accommodation conflict.

[0077] Figure 6 is a structural schematic diagram of another near-eye display device provided in an embodiment of the present disclosure; Figure 7 is a structural schematic diagram of another near-eye display device provided in an embodiment of the present disclosure.

[0078] As shown in Figures 6 and 7, in this embodiment of the application, the near-eye display device further includes an imaging lens group 3. The imaging lens group 3 is used to converge or diverge the light emitted from the display component 1, so that it forms a clear image at a specific position for human viewing. Specifically, the imaging lens group 3 may include at least one imaging lens. The surface shape, thickness, and spacing of the imaging lens can be designed to achieve clear imaging and reduce aberrations. The number of imaging lenses, the relative positional relationship of each imaging lens, and the surface shape, thickness, and spacing of each imaging lens all need to be designed according to the specific product requirements, and this embodiment does not limit these aspects.

[0079] The position of the imaging lens group 3 in the near-eye display device can also be set according to the requirements. For example, as shown in Figure 6, the imaging lens group 3 can be located between the display component 1 and the zoom component 2, or, as shown in Figure 7, the imaging lens group 3 can be located on the light-emitting side of the zoom component 2.

[0080] Figure 8 is a structural schematic diagram of another near-eye display device provided in an embodiment of the present disclosure; Figure 9 is a structural schematic diagram of another near-eye display device provided in an embodiment of the present disclosure; Figure 10 is a structural schematic diagram of another near-eye display device provided in an embodiment of the present disclosure.

[0081] When the near-eye display device includes two or more zoom components 2, referring to Figure 8, the imaging lens group 3 can be located between the display component 1 and the multiple zoom components 2, or referring to Figure 9, the imaging lens group 3 can be located in the light output path of the multiple zoom components 2, or referring to Figure 10, the imaging lens group 3 can be located between any two zoom components 2 among the multiple zoom components 2.

[0082] Figure 11 is a schematic diagram of another near-eye display device provided in an embodiment of this disclosure.

[0083] As shown in Figure 11, in this embodiment of the present disclosure, the near-eye display device further includes a first phase delay layer 4 and an optical path refracting component 5, wherein the first phase delay layer 4 is located between the display component 1 and the optical path refracting component 5.

[0084] The first phase delay layer 4 is used to delay the phase of the incident linearly polarized light by π / 2 to convert it into circularly polarized light for emission. That is, the first phase delay layer 4 is a quarter-wave plate. The first phase delay layer 4 is set to meet the polarization state requirements of the optical path folding component 5 for the incident light.

[0085] The optical path folding component 5 is used to reflect circularly polarized light multiple times and convert it into linearly polarized light for emission. The light is reflected multiple times in the optical path folding component 5, which can effectively reduce the thickness of the device, realize a thin and light design, reduce the weight and volume of the near-eye display device, improve wearing comfort, and also improve edge imaging quality and reduce image distortion.

[0086] Specifically, the optical path reversal assembly 5 may include a partially reflective and partially transmissive layer 51, a second phase retardation layer 52, and a reflective polarizer 53 arranged sequentially away from the first phase retardation layer 4. The second phase retardation layer 52 is used to delay the phase of the incident light by π / 2, i.e., the second phase retardation layer 52 is a quarter-wave plate. The reflective polarizer 53 is used to reflect the first linearly polarized light L1 and transmit the second linearly polarized light L2.

[0087] The optical path in the optical path folding assembly 5 is as follows: The first circularly polarized light C1 emitted from the first phase retardation layer 4 is incident on the partially reflective and partially transmissive layer 51 and partially transmissive to the second phase retardation layer 52. The second phase retardation layer 52 converts the first linearly polarized light L1 and emits it to the reflective polarizer 53. The reflective polarizer 53 reflects the first linearly polarized light L1 to the second phase retardation layer 52. The second phase retardation layer 52 converts the first linearly polarized light L1 into the first circularly polarized light C1 and emits it to the partially reflective and partially transmissive layer 51. The partially reflective and partially transmissive layer 51 reflects part of the circularly polarized light to the second phase retardation layer 52 and converts the part of the circularly polarized light into the second circularly polarized light C2. The rotation direction of the second circularly polarized light C2 is opposite to the rotation direction of the first circularly polarized light C1. The second phase retardation layer 52 converts the second circularly polarized light C2 into the second linearly polarized light L2 and emits it to the reflective polarizer 53. The reflective polarizer 53 transmits the second linearly polarized light L2 out.

[0088] In some embodiments, the optical path reversing assembly 5 may further include a second linear polarizer 54, which is located in the light output path of the reflective polarizer 53 and is used to transmit the second linearly polarized light L2. The reflective polarizer 53 is emitted to the second linear polarizer 54 to ensure that the light emitted from the optical path reversing assembly 5 is the second linearly polarized light L2.

[0089] The positions of the first phase delay layer 4 and the optical path refraction component 5 in the near-eye display device can also be set according to specific requirements. For example, as shown in Figure 11, the zoom component 2 can be located on the light output path of the optical path refraction component 5, and the second linearly polarized light L2 emitted from the optical path refraction component 5 is incident on the zoom component 2. As shown in Figure 11(a), when no voltage is applied to the first liquid crystal polarization rotator 21, the first liquid crystal polarization rotator 21 emits the second linearly polarized light L2, which is focused at the second focal length f2 after passing through the liquid crystal lens 22; as shown in Figure 11(b), when a voltage is applied to the first liquid crystal polarization rotator 21, the first liquid crystal polarization rotator 21 converts the incident second linearly polarized light L2 into the first linearly polarized light L1 for emission, which is focused at the first focal length f1 after passing through the liquid crystal lens 22.

[0090] Figure 12 is a schematic diagram of another near-eye display device provided in an embodiment of this disclosure.

[0091] As shown in Figure 12, in this embodiment of the present disclosure, the zoom component 2 can be located between the display component 1 and the first phase delay layer 4. As can be seen from the principle of the optical path refraction component 5, the light incident on the optical path refraction component 5 needs to be the first linearly polarized light L1. Therefore, the near-eye display device also includes a second liquid crystal polarization rotator 6, which is located between the zoom component 2 and the first phase delay layer 4 to ensure that the polarization direction of the light incident on the optical path refraction component 5 meets the requirements.

[0092] As shown in Figure 12(a), when no voltage is applied to the first liquid crystal polarization rotator 21, the first liquid crystal polarization rotator 21 emits first linearly polarized light L1, which is focused at the first focal length f1 after passing through the liquid crystal lens 22. At the same time, no voltage is applied to the second liquid crystal polarization rotator 6, and the second liquid crystal polarization rotator 6 emits the first linearly polarized light L1. The first linearly polarized light L1 is converted into second linearly polarized light L2 after passing through the first phase retardation layer 4 and the optical path folding component 5. As shown in Figure 12(b), when a voltage is applied to the first liquid crystal polarization rotator 21, the first liquid crystal polarization rotator 21 emits second linearly polarized light L2, which is focused at the second focal length f2 after passing through the liquid crystal lens 22. At the same time, a voltage is applied to the second liquid crystal polarization rotator 6, causing the second liquid crystal polarization rotator 6 to convert the second linearly polarized light L2 into the first linearly polarized light L1 for emission. The first linearly polarized light L1 is converted into the second linearly polarized light L2 after passing through the first phase retardation layer 4 and the optical path folding component 5.

[0093] To further aid in understanding the zoom principle of the zoom assembly 2 provided in this embodiment, the specific structures of the first liquid crystal polarization rotator 21 and the liquid crystal lens 22 in the zoom assembly 2 will be described below.

[0094] Figure 13 is a schematic diagram of the structure of a first liquid crystal polarization rotator provided in an embodiment of this disclosure.

[0095] As shown in Figure 13, the first liquid crystal polarization rotator 21 may include a first liquid crystal layer 211, with alignment layers 212 respectively disposed on both sides of the first liquid crystal layer 211, an electrode layer 213 disposed on the side of each alignment layer 212 away from the first liquid crystal layer 211, and a substrate 214 disposed on the side of each electrode layer 213 away from the alignment layer 212. By controlling the electrical signal applied to the electrode layer 213, the liquid crystal molecules in the first liquid crystal layer 211 can be deflected, thereby controlling the light emitted from the first liquid crystal polarization rotator 21 to switch between first linearly polarized light and second linearly polarized light.

[0096] Figure 14 is a graph showing the dispersion characteristics of the first liquid crystal polarization rotator corresponding to Figure 13.

[0097] Figure 14 shows the stray light ratios of different wavelengths of light emitted from the first liquid crystal polarization rotator 21 shown in Figure 13, under both powered and unpowered conditions. The horizontal axis represents wavelength in nanometers (nm), and the vertical axis represents the percentage of stray light in the emitted light. As shown in Figure 14, when the first liquid crystal polarization rotator 21 includes a first liquid crystal layer 211, if no voltage is applied to the first liquid crystal layer 211, the emitted light from the first liquid crystal polarization rotator 21 has a relatively large amount of stray light in the red light band (610nm-730nm) and the blue light band (400nm-500nm). This is because the first liquid crystal polarization rotator 21 is relatively thick, and the liquid crystal molecules are not fully aligned during the manufacturing process, with some liquid crystal molecules deflecting at different angles than other liquid crystal molecules. If a voltage is applied to the first liquid crystal layer 211, the liquid crystal molecules in the first liquid crystal layer 211 deflect at the same angle, and the emitted light from the first liquid crystal polarization rotator 21 basically does not contain stray light. It is evident that if the thickness of the first liquid crystal layer 211 is large, it may cause stray light in the light emitted from the first liquid crystal polarization rotator 21, resulting in chromatic dispersion in the image and affecting the image quality to some extent.

[0098] Figure 15 is a schematic diagram of another first liquid crystal polarization rotator provided in an embodiment of this disclosure.

[0099] As shown in Figure 15(a), the first liquid crystal polarization rotator 21 may include two first liquid crystal layers 211. An alignment layer 212 is provided on both sides of each first liquid crystal layer 211. An electrode layer 213 is provided on the side of each alignment layer 212 away from the first liquid crystal layer 211. A substrate 214 is provided on the side of each electrode layer 213 away from the alignment layer 212. By controlling the electrical signal applied to each electrode layer 213, the rotation of liquid crystal molecules in each first liquid crystal layer 211 can be controlled. The two first liquid crystal layers 211 cooperate to realize the function of a half-wave plate and control the switching of the light emitted from the first liquid crystal polarization rotator 21 between first linearly polarized light and second linearly polarized light.

[0100] As shown in Figure 15(b), the two first liquid crystal layers 211 can share the same electrode layer 213, which simplifies the process flow of the first liquid crystal polarization rotator 21 and helps to reduce the thickness of the first liquid crystal polarization rotator 21.

[0101] Figure 16 is a graph showing the dispersion characteristics of the first liquid crystal polarization rotator corresponding to Figure 15.

[0102] Figure 16 shows the proportion of stray light after light of different wavelengths is emitted from the first liquid crystal polarization rotator 21 shown in Figure 15, under both powered and unpowered conditions. The horizontal axis represents wavelength in nanometers (nm), and the vertical axis represents the percentage of stray light in the emitted light. As shown in Figure 16, when the first liquid crystal polarization rotator 21 comprises two first liquid crystal layers 211, the proportion of stray light in the emitted light is relatively small regardless of whether a voltage is applied to the first liquid crystal layers 211 or not.

[0103] In this embodiment, the first liquid crystal polarization rotator 21 is provided with two first liquid crystal layers 211 to cooperate in realizing the function of a half-wave plate. Each first liquid crystal layer 211 can have a small thickness, which can improve the response speed of each first liquid crystal layer 211. On the other hand, during the preparation, the liquid crystal molecules in the first liquid crystal layer 211 can be more fully oriented, which is beneficial to reduce the proportion of stray light in the light emitted from the first liquid crystal polarization rotator 21, improve the dispersion phenomenon of the image, and improve the image quality.

[0104] It is understandable that the first liquid crystal polarization rotator 21 can also have more first liquid crystal layers 211, arranged sequentially along the optical path. The thickness of each first liquid crystal layer 211 can be further reduced, thereby improving the response speed of the first liquid crystal polarization rotator 21. Each first liquid crystal layer 211 has an electrode layer 213 on both sides, or at least two adjacent first liquid crystal layers 211 can share the same electrode layer 213, or every two adjacent first liquid crystal layers 211 can share the same electrode layer 213. The number of first liquid crystal layers 211 and electrode layers 213 in the first liquid crystal polarization rotator 21 can be designed according to specific requirements and is not limited here.

[0105] For example, in the first liquid crystal polarization rotator 21, the material of each substrate 214 can be one of, but not limited to, glass, TAC, PI, etc., and the liquid crystal mode of each first liquid crystal layer 211 can be one of, but not limited to, electrically controlled birefringence (ECB), vertical alignment liquid crystal (VA), or optically compensated birefringence (OCB).

[0106] Figure 17 is a schematic diagram of the structure of a liquid crystal lens provided in an embodiment of this disclosure.

[0107] As shown in Figure 17, in this embodiment of the present disclosure, the liquid crystal lens 22 includes a second liquid crystal layer 221, which includes a light-incident surface 2201 and a light-emitting surface 2202. As shown in Figure 17(a), the light-incident surface 2201 of the second liquid crystal layer 221 can be configured as a curved surface and the light-emitting surface 2202 as a flat surface; or, as shown in Figure 17(b), the light-incident surface 2201 of the second liquid crystal layer 221 can be configured as a flat surface and the light-emitting surface 2202 as a curved surface; or, as shown in Figure 17(c), both the light-incident surface 2201 and the light-emitting surface 2202 of the second liquid crystal layer 221 can be configured as curved surfaces. For example, the curved surface can be an aspherical surface.

[0108] The liquid crystal lens 22 provided in this embodiment is a solid-state liquid lens. It does not require applying a voltage to achieve imaging on different focal planes. Instead, by setting the light-incident surface 2201 and / or the light-exit surface 2202 of the second liquid crystal layer 221 as curved surfaces, at least some of the liquid crystal molecules can have different deflection directions. Based on the anisotropy of the liquid crystal material, linearly polarized light with different polarization directions can be focused by the liquid crystal lens 22 at different focal lengths. The liquid crystal lens 22 has a simple structure and its response speed is not limited by the thickness of the second liquid crystal layer 221, which can achieve fast imaging.

[0109] The radii of curvature of the light-incident surface 2201 and the light-exit surface 2202 of the second liquid crystal layer 221, as well as the thickness of the second liquid crystal layer 221, can be designed according to specific requirements, and are not limited in this embodiment. For example, the maximum thickness of the second liquid crystal layer 221 can be greater than 100 μm, or the maximum thickness of the second liquid crystal layer 221 can be greater than 500 μm, so as to ensure that the liquid crystal lens 22 can have good imaging quality.

[0110] Figure 18 is a schematic diagram of another liquid crystal lens provided in an embodiment of this disclosure.

[0111] As shown in Figure 18, in this embodiment of the present disclosure, the liquid crystal lens 22 may further include: a first substrate 222, a second substrate 223, a first alignment layer 224, and a second alignment layer 225. The first substrate 222 and the second substrate 223 are disposed opposite to each other. The first alignment layer 224 is located on the surface of the first substrate 222 facing the second substrate 223, and the second alignment layer 225 is located on the surface of the second substrate 223 facing the first substrate 222. The second liquid crystal layer 221 is located between the first alignment layer 224 and the second alignment layer 225. The second liquid crystal layer 221 can be any of the three types of second liquid crystal layers 221 shown in Figure 17. The shape of the surface of the first substrate 222 facing the second liquid crystal layer 221 matches the shape of the light-incident surface 2201 of the second liquid crystal layer 221, and the shape of the surface of the second substrate 223 facing the second liquid crystal layer 221 matches the shape of the light-emitting surface 2202 of the second liquid crystal layer 221. The materials of the first substrate 222 and the second substrate 223, as well as the shapes of other surfaces, are not limited here and can be designed according to the requirements of the imaging focal length. In this embodiment of the present disclosure, the first substrate 222 and the second substrate 223 support the second liquid crystal layer 221 and can also assist in imaging.

[0112] Based on the same concept, this disclosure also provides a method for manufacturing a liquid crystal lens 22. The manufacturing process of the liquid crystal lens 22 will be described below using the structure of the liquid crystal lens 22 shown in Figure 17(a) as an example.

[0113] Figure 19 is a schematic diagram of the manufacturing process of a liquid crystal lens provided in an embodiment of the present disclosure; Figure 20 is a schematic diagram of the manufacturing process of another liquid crystal lens provided in an embodiment of the present disclosure.

[0114] As shown in Figures 19 and 20, the method for manufacturing the liquid crystal lens 22 may include the following steps:

[0115] Step S1: Form a first alignment layer 224 on the first substrate 222. For example, referring to Figures 19(a) and 20(a), a curved surface can be formed on one side surface of the substrate by a molding process to form the first substrate 222. The substrate can be a transparent material such as glass. Referring to Figures 19(b) and 20(b), polyimide (PI) is coated on the curved surface, and the first alignment layer 224 is formed on the curved surface of the first substrate 222 by ultraviolet (UV) curing or high temperature curing.

[0116] Step S2: Form a second alignment layer 225 on the second substrate 223. For example, referring to (c) in FIG19 and (c) in FIG20, a flat glass is used as the second substrate 223, PI is coated on one side surface of the second substrate 223, and the second alignment layer 225 is formed by UV curing or high temperature curing.

[0117] Step S3: Assemble the first substrate 222 and the second substrate 223. For example, referring to (d) in FIG19 and (d) in FIG20, the first substrate 222 can be aligned with the second substrate 223 on top and the second substrate 223 on the bottom, and a shim or pad T is provided between the first substrate 222 and the second substrate 223 to control the thickness.

[0118] Step S4: Inject liquid crystal material between the first substrate 222 and the second substrate 223. For example, the alignment device in step S3 can be placed in a temperature-controlled chamber for preheating, for example, preheating to 80°C. Take an appropriate amount of curable liquid crystal and heat it to a clearing point. Then, referring to Figure 19(e), the liquid crystal in the liquid crystal tank can be injected between the first substrate 222 and the second substrate 223 by vacuum suction. Alternatively, referring to Figure 20(e), the liquid crystal can be injected between the first substrate 222 and the second substrate 223 by high-pressure injection.

[0119] Step S5: Curing the liquid crystal material to form the second liquid crystal layer 221. For example, referring to (f) and (g) in Figure 19 and (f) and (g) in Figure 20, the device formed in step S4 can be placed on a heating platform for planarization and orientation. A strong electric field can also be applied to the liquid crystal for auxiliary orientation to obtain a better orientation effect. After orientation is completed, UV curing is performed to form the second liquid crystal layer 221.

[0120] Step S6: Remove the first substrate 222 and the second substrate 223. For example, referring to (h) in FIG19 and (h) in FIG20, removing the first substrate 222 and the first alignment layer 224 on the first substrate 222, and removing the second substrate 223 and the second alignment layer 225 on the second substrate 223, yields the liquid crystal lens 22 shown in FIG17(a). If the liquid crystal lens 22 shown in FIG18 is to be fabricated, step S6 is omitted.

[0121] Although preferred embodiments of this application have been described, those skilled in the art, upon learning the basic inventive concept, can make other changes and modifications to these embodiments. Therefore, the appended claims are intended to be interpreted as including the preferred embodiments as well as all changes and modifications falling within the scope of this application.

[0122] Obviously, those skilled in the art can make various modifications and variations to the embodiments of this application without departing from the spirit and scope of the embodiments of this application. Therefore, if these modifications and variations to the embodiments of this application fall within the scope of the claims of this application and their equivalents, this application also intends to include these modifications and variations.

Claims

1. A near-eye display device, wherein, The near-eye display device includes: Display components are used to output polarized light; A zoom component is located in the light-emitting path of the display component; the zoom component includes: A first liquid crystal polarization rotator is used to switch incident linearly polarized light between a first linearly polarized light and a second linearly polarized light for output, wherein the phase difference between the first linearly polarized light and the incident linearly polarized light is 0, and the phase difference between the second linearly polarized light and the incident linearly polarized light is π. A liquid crystal lens is located in the light output path of the first liquid crystal polarization rotator; the liquid crystal lens is used to focus the first linearly polarized light or the second linearly polarized light emitted from the first liquid crystal polarization rotator onto different focal lengths.

2. The near-eye display device as claimed in claim 1, wherein, The zoom components are multiple, and the multiple zoom components are arranged sequentially along the light output path of the display component.

3. The near-eye display device as described in claim 2, wherein, The plurality of zoom components are used to zoom the image from the display component in 2 to 2 n Switching between focal planes, where n is the number of zoom components.

4. The near-eye display device as claimed in claim 1, wherein, The near-eye display device further includes an imaging lens group, which is located between the display component and the zoom component, or the imaging lens group is located on the light-emitting side of the zoom component.

5. The near-eye display device as claimed in claim 2, wherein, The near-eye display device further includes an imaging lens group, which is located between the display component and the plurality of zoom components, or the imaging lens group is located in the light output path of the plurality of zoom components, or the imaging lens group is located between any two of the plurality of zoom components.

6. The near-eye display device as described in claim 4 or 5, wherein, The imaging lens group includes at least one imaging lens.

7. The near-eye display device as claimed in claim 1, wherein, The near-eye display device further includes a first phase retardation layer and an optical path refracting component. The first phase retardation layer is located between the display component and the optical path refracting component. The first phase retardation layer is used to delay the phase of the incident linearly polarized light by π / 2 to convert it into circularly polarized light for emission. The optical path refracting component is used to reflect the circularly polarized light multiple times and convert it into linearly polarized light for emission.

8. The near-eye display device as claimed in claim 7, wherein, The zoom component is located on the light output path of the optical path folding component.

9. The near-eye display device as claimed in claim 7, wherein, The zoom component is located between the display component and the first phase retardation layer; the near-eye display device further includes a second liquid crystal polarization rotator, which is located between the zoom component and the first phase retardation layer.

10. The near-eye display device according to any one of claims 7-9, wherein, The optical path reversal assembly includes a partially reflective and partially transmissive layer, a second phase retardation layer, and a reflective polarizer arranged sequentially away from the first phase retardation layer. The second phase retardation layer is used to delay the phase of the incident light by π / 2, and the reflective polarizer is used to reflect the first linearly polarized light and transmit the second linearly polarized light.

11. The near-eye display device according to any one of claims 1-10, wherein, The first liquid crystal polarization rotator includes at least one first liquid crystal layer, and in the first liquid crystal polarization rotator, electrode layers are disposed on both sides of each first liquid crystal layer.

12. The near-eye display device as claimed in claim 11, wherein, At least two adjacent first liquid crystal layers share the same electrode layer.

13. The near-eye display device as claimed in claim 11, wherein, The first liquid crystal layer is one of an electrically controlled birefringent liquid crystal, a vertically aligned liquid crystal, or an optically compensated bending liquid crystal.

14. The near-eye display device according to any one of claims 1-13, wherein, The liquid crystal lens includes a second liquid crystal layer, which includes an incident light surface and an exit light surface, wherein the incident light surface and / or the exit light surface is a curved surface.

15. The near-eye display device as claimed in claim 14, wherein, The liquid crystal lens further includes: a first substrate, a second substrate, a first alignment layer and a second alignment layer, wherein the first substrate and the second substrate are disposed opposite to each other, the first alignment layer is located on the surface of the first substrate facing the second substrate, the second alignment layer is located on the surface of the second substrate facing the first substrate, the surface where the first alignment layer and / or the second alignment layer are located is a curved surface, and the second liquid crystal layer is located between the first alignment layer and the second alignment layer.

16. The near-eye display device as claimed in claim 15, wherein, The surface in question is aspherical.

17. The near-eye display device as claimed in claim 14, wherein, The maximum thickness of the second liquid crystal layer is greater than 100 μm, or the maximum thickness of the second liquid crystal layer is greater than 500 μm.

18. A control method for a near-eye display device as described in any one of claims 1-17, wherein, The control method includes: The output light from the first liquid crystal polarization rotator is switched between first linearly polarized light and second linearly polarized light according to the depth information of the image to be displayed by the display component; the phase difference between the first linearly polarized light and the linearly polarized light incident on the first liquid crystal polarization rotator is 0, and the phase difference between the second linearly polarized light and the linearly polarized light incident on the first liquid crystal polarization rotator is π.

19. The control method as described in claim 18, wherein, The step of controlling the output light of the first liquid crystal polarization rotator to switch between first linearly polarized light and second linearly polarized light according to the depth information of the image to be displayed by the display component includes: When the depth information of the displayed image is less than or equal to a preset threshold, the first liquid crystal polarization rotator is controlled to emit the first linearly polarized light. When the depth information of the displayed image is greater than the preset threshold, the first liquid crystal polarization rotator is controlled to emit the second linearly polarized light.

20. The control method as described in claim 18, wherein, The control method further includes: The display component is controlled to display images with the same image but different brightness in two consecutive frames, while the first liquid crystal polarization rotator is controlled to emit the first linearly polarized light and the second linearly polarized light in the two consecutive frames respectively.

Images