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] The present disclosure relates to the field of near-eye display technology, and in particular to a near-eye display device and a control method. Background Art

[0002] Near-eye display technology is a technology that creates a virtual scene in front of the human eyes through a display device located within the non-clear vision distance of the human eye. It includes augmented reality (AR), virtual reality (VR), mixed reality (MR), and other types.

[0003] Normally, when the human eye views an object in a display environment, the convergence function and the focusing function of the human eye are coordinated with each other. The convergence function converges the sights of both eyes on the same object, while the focusing function focuses on the object at the same distance. However, in near-eye display devices, in order to provide an immersive experience, the displayed image on the display element will show a certain depth, but in fact the distance between the display element and the human eye is unchanged. Therefore, when the human eye tries to focus on different depths to obtain virtual objects, the sight position of the human eye is different from the focus position. In this way, the convergence function and the focusing function conflict, which is called convergence accommodation conflict. The existence of convergence accommodation conflict forces the brain to synthesize information that the sight and focus are not in the same position. Over time, it will cause adverse reactions such as visual fatigue, dizziness and headaches, affecting the experience.

[0004] Summary of the Invention

[0005] The present disclosure provides a near-eye display device and a control method for eliminating convergence accommodation conflicts.

[0006] In a first aspect, the present disclosure provides a near-eye display device, comprising: a display assembly for emitting linearly polarized light;

[0007] A zoom component is located on the light output path of the display component; the zoom component includes:

[0008] a first liquid crystal polarization rotator, configured to switch the incident linearly polarized light between a first linearly polarized light and a second linearly polarized light, 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] The liquid crystal lens is located on 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 by the first liquid crystal polarization rotator onto different focal lengths.

[0010] In some embodiments of the present disclosure, there are multiple zoom assemblies, and the multiple zoom assemblies are arranged in sequence along the light output path of the display assembly.

[0011] In some embodiments of the present disclosure, 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.

[0012] In some embodiments of the present disclosure, the near-eye display device further includes an imaging lens group, which is located between the display component and the multiple zoom components, or the imaging lens group is located on the light-emitting path of the multiple zoom components, or the imaging lens group is located between any two zoom components among the multiple zoom components.

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

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

[0015] In some embodiments of the present disclosure, the zoom component is located on the light output path of the light path folding component.

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

[0017] In some embodiments of the present disclosure, the optical path folding component includes a partially reflective and partially transmissive layer, a second phase delay layer, and a reflective polarizer arranged in sequence away from the first phase delay layer, the second phase delay layer is used to delay the phase of the incident light by π / 2, and the reflective polarizer is used to reflect the first linear polarized light and transmit the second linear polarized light.

[0018] In some embodiments of the present disclosure, the first liquid crystal polarization rotator includes at least one first liquid crystal layer. 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 the present disclosure, at least two adjacent first liquid crystal layers share the same electrode layer.

[0020] In some embodiments of the present disclosure, the first liquid crystal layer is one of electrically controlled birefringence liquid crystal, vertically aligned liquid crystal, or optically compensated bend liquid crystal.

[0021] In some embodiments of the present disclosure, the liquid crystal lens includes a second liquid crystal layer, the second liquid crystal layer includes a light incident surface and a light emitting surface, and the light incident surface and / or the light emitting surface are curved surfaces.

[0022] In some embodiments of the present 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 being arranged opposite to each other, the first alignment layer being located on a surface of the first substrate facing the second substrate, the second alignment layer being located on a surface of the second substrate facing the first substrate, the surface on which 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.

[0023] In some embodiments of the present disclosure, the curved surface is an aspherical surface.

[0024] In a second aspect, the present disclosure also provides a control method for a near-eye display device, including: controlling the outgoing light of a first liquid crystal polarization rotator to switch between a first linear polarized light and a second linear polarized light according to depth information of an image required to be displayed by a display component; the phase difference between the first linear polarized light and the linear polarized light incident to the first liquid crystal polarization rotator is 0, and the phase difference between the second linear polarized light and the linear polarized light incident to the first liquid crystal polarization rotator is π.

[0025] In some embodiments of the present disclosure, controlling the output light of the first liquid crystal polarization rotator to switch between the first linearly polarized light and the second linearly polarized light according to 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, controlling the first liquid crystal polarization rotator 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 the present disclosure, the control method further includes:

[0029] The display component is controlled to sequentially display images with the same picture but different brightness in two consecutive frames, and the first liquid crystal polarization rotator is controlled to respectively emit the first linearly polarized light and the second linearly polarized light in the two consecutive frames. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] FIG1 is a schematic structural diagram of a near-eye display device provided by an embodiment of the present disclosure;

[0031] FIG2 is a schematic diagram showing the principle of a zoom assembly provided by an embodiment of the present disclosure;

[0032] FIG3 is one of the principle diagrams of the control method provided by an embodiment of the present disclosure;

[0033] FIG4 is a second schematic diagram of the control method provided by an embodiment of the present disclosure;

[0034] FIG5 is a schematic structural diagram of another near-eye display device provided by an embodiment of the present disclosure;

[0035] FIG6 is a schematic structural diagram of another near-eye display device provided by an embodiment of the present disclosure;

[0036] FIG7 is a schematic structural diagram of another near-eye display device provided by an embodiment of the present disclosure;

[0037] FIG8 is a schematic structural diagram of another near-eye display device provided by an embodiment of the present disclosure;

[0038] FIG9 is a schematic structural diagram of another near-eye display device provided by an embodiment of the present disclosure;

[0039] FIG10 is a schematic structural diagram of another near-eye display device provided by an embodiment of the present disclosure;

[0040] FIG11 is a schematic structural diagram of another near-eye display device provided by an embodiment of the present disclosure;

[0041] FIG12 is a schematic structural diagram of another near-eye display device provided by an embodiment of the present disclosure;

[0042] FIG13 is a schematic structural diagram of a first liquid crystal polarization rotator provided by an embodiment of the present disclosure;

[0043] FIG14 is a dispersion characteristic curve diagram of the first liquid crystal polarization rotator corresponding to FIG13;

[0044] FIG15 is a schematic structural diagram of another first liquid crystal polarization rotator provided in an embodiment of the present disclosure;

[0045] FIG16 is a dispersion characteristic curve diagram of the first liquid crystal polarization rotator corresponding to FIG15;

[0046] FIG17 is a schematic structural diagram of a liquid crystal lens provided by an embodiment of the present disclosure;

[0047] FIG18 is a schematic structural diagram of another liquid crystal lens provided by an embodiment of the present disclosure;

[0048] FIG19 is a schematic diagram of a manufacturing process of a liquid crystal lens provided by an embodiment of the present disclosure;

[0049] FIG20 is a schematic diagram of a manufacturing process of another liquid crystal lens provided in an embodiment of the present disclosure.

[0050] Figure 1: Display component 1, display panel 11, first linear polarizer 12, zoom component 2, first liquid crystal polarization rotator 21, liquid crystal lens 22, first linear polarized light L1, second linear 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 delay layer 4, optical path return component 5, part Partially reflective and partially transmissive layer 51, second phase retardation layer 52, reflective polarizer 53, second linear polarizer 54, first circularly polarized light C1, second circularly polarized light C2, second liquid crystal polarization rotator 6, first liquid crystal layer 211, orientation layer 212, electrode layer 213, substrate 214, light incident surface 2201, light exit surface 2202, second liquid crystal layer 221, first substrate 222, second substrate 223, first orientation layer 224, second orientation layer 225, and spacer T. DETAILED DESCRIPTION

[0051] In order to make the purpose, technical solutions and advantages of the embodiments of the present disclosure clearer, the technical solutions of the embodiments of the present disclosure will be clearly and completely described below in conjunction with the drawings of the embodiments of the present disclosure. Obviously, the described embodiments are part of the embodiments of the present disclosure, not all of the embodiments. And in the absence of conflict, the embodiments in the present disclosure and the features in the embodiments can be combined with each other. Based on the described embodiments of the present disclosure, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present disclosure.

[0052] Unless otherwise defined, technical or scientific terms used in this disclosure should have the same general meaning as those generally understood by persons skilled in the art in the art to which this disclosure pertains. The terms "first," "second," and similar terms used in this disclosure do not denote any order, quantity, or importance, but are merely used to distinguish different components.

[0053] It should be noted that the sizes and shapes of the figures in the accompanying drawings do not reflect the actual scale and are only for the purpose of illustrating the contents of this application. The same or similar reference numerals throughout represent the same or similar elements or elements with the same or similar functions.

[0054] FIG1 is a schematic structural diagram of a near-eye display device provided in an embodiment of the present disclosure.

[0055] As shown in FIG1 , the near-eye display device provided by the embodiment of the present disclosure includes a display component 1 and a zoom component 2 , and the zoom component 2 is located on the light-emitting path of the display component 1 .

[0056] The display assembly 1 is used to emit linearly polarized light. The display assembly 1 may specifically 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 assembly 2. For example, the first linear polarizer 12 may be attached to the light-emitting surface of the display. The type of the display panel 11 includes, but is not limited to, a light-emitting diode (Mini-LED) display panel, a Mini-LED display panel, a Micro-LED display panel, an Organic Light-Emitting Diode (OLED) display panel, or 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 the first linearly polarized light and the second linearly polarized light. The phase difference between the first linearly polarized light and the incident linear polarized light is 0, and the phase difference between the second linear polarized light and the incident linear polarized light is π. Exemplarily, 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 on 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 by the first liquid crystal polarization rotator 21 to different focal lengths, that is, to form images on different focal planes.

[0059] FIG2 is a schematic diagram showing the principle of a zoom assembly provided in an embodiment of the present disclosure.

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

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

[0062] Based on the aforementioned 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 be switched 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 directions of the first linearly polarized light L1 and the second linearly polarized light L2 are determined by the polarization direction of the linearly polarized light emitted by 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 can be transmitted by it, the polarization direction of the linearly polarized light incident on the first liquid crystal polarization rotator 21 can be changed. The polarization directions of the first linearly polarized light L1 and the second linearly polarized light L2 are exchanged without affecting the zoom principle.

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

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

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

[0067] FIG3 is one of the principle diagrams of the control method provided in an embodiment of the present disclosure.

[0068] For ease of description, two consecutive display frames are referred to as the first and second frames. The light composing the first and second frames enters the first liquid crystal polarization rotator 21. As shown in FIG3 , when the light composing the first frame is controlled to exit the first liquid crystal polarization rotator 21 as first polarized light, the first frame is imaged on a first depth plane P1, with the resulting virtual image at a distance Z1 from the human eye. When the light composing the second frame is controlled to exit the first liquid crystal polarization rotator 21 as second polarized light, the second frame is imaged on a second depth plane P2, with the resulting virtual image at a distance Z2 from the human eye. By adjusting the brightness ratio between the first and second frames, the human eye perceives a composite image composed of the first and second frames, based on the persistence of vision effect. The image perceived by the human eye is located on a third depth plane P between the first depth plane P1 and the second depth plane P2.

[0069] Exemplarily, 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 screen observed by the human eye is located on the first depth of field 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 screen observed by the human eye is located on the first depth of field 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 screen observed by the human eye is located on the third depth of field plane P.

[0070] FIG4 is a second schematic diagram of the control method provided in an embodiment of the present disclosure.

[0071] FIG4 shows a relationship curve between the position of the third depth plane P and the first and second display images when the brightness ratios are different. The horizontal axis represents the brightness ratio (Intensity Ratio), and the vertical axis represents the adjustment distance (Accommodation Distance) which can reflect the position of the third depth plane P. The unit is the reciprocal of the distance. The four broken lines represent the display images of single-frequency signal images of 4 cpd, 9 cpd, and 21 cpd, and composite frequency signal images of 0-30 cpd. As can be seen from FIG4, when the display images are of different frequency signals, even if the first and second display images have the same brightness ratio, the position of the third depth plane P is different. Therefore, for display images mainly of different frequencies, the brightness ratio of the first and second display images needs to be adjusted according to the actual situation.

[0072] FIG5 is a schematic structural diagram of another near-eye display device provided in an embodiment of the present disclosure.

[0073] As shown in FIG5 , the near-eye display device may include two zoom assemblies, which are arranged in sequence along the light path of the display assembly 1. For ease of description, the two zoom assemblies 2 are referred to as the first zoom assembly 201 and the second zoom assembly 202, respectively. The light emitted by the display assembly 1 is focused by the first zoom assembly 201 and then focused by the second zoom assembly 202. The final imaging position can be as follows:

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

[0075] It can be seen that in the above four cases, the focal planes of the final image of the display screen are all different. By setting two zoom components 2, the embodiment of the present disclosure can realize the switching of the imaging screen between 2 to 4 focal planes, thereby expanding the focusing range of the human eye.

[0076] In the embodiment of the present disclosure, there can be multiple zoom components 2, and the multiple zoom components 2 are arranged in sequence along the light path of the display component 1. The zoom principle of the near-eye display device shown in Figures 2 and 5 can be inferred by analogy. Each zoom component 2 can realize the switching of the imaging picture between two focal planes, so the multiple zoom components 2 can realize the switching of the imaging picture between 2 and 2 n Switching between focal planes, where n is the number of zoom assemblies 2. Multiple zoom assemblies 2 are provided in the near-eye display device. Through the mutual cooperation of the multiple zoom assemblies 2, the imaging image can be switched between more focal planes, providing greater freedom of focus for the human eye and further alleviating problems such as visual fatigue caused by convergence and accommodation conflicts.

[0077] FIG6 is a schematic structural diagram of another near-eye display device provided in an embodiment of the present disclosure; FIG7 is a schematic structural diagram of another near-eye display device provided in an embodiment of the present disclosure.

[0078] As shown in Figures 6 and 7, in the embodiment of the present application, the near-eye display device also includes an imaging lens group 3, which is used to converge or diverge the outgoing light from the display component 1, so that it forms a clear image at a specific position for human viewing. The imaging lens group 3 can specifically include at least one imaging lens. By designing the parameters such as the surface shape, thickness, and spacing of the imaging lens, it is possible to achieve the effect of clear imaging and reduced aberration. The number of imaging lenses, the relative position relationship of each imaging lens, the surface shape, thickness, and spacing of each imaging lens, and other parameters need to be designed according to the specific product requirements and are not limited in the embodiment of the present disclosure.

[0079] The position of the imaging lens group 3 in the near-eye display device can also be set according to needs. 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 assemblies 2, referring to Figure 8, the imaging lens group 3 can be located between the display assembly 1 and the multiple zoom assemblies 2, or, referring to Figure 9, the imaging lens group 3 can be located on the light output path of the multiple zoom assemblies 2, or, referring to Figure 10, the imaging lens group 3 can be located between any two zoom assemblies 2 among the multiple zoom assemblies 2.

[0082] FIG11 is a schematic structural diagram of another near-eye display device provided in an embodiment of the present disclosure.

[0083] As shown in FIG11 , in the embodiment of the present disclosure, the near-eye display device further includes a first phase delay layer 4 and an optical path folding component 5 , and the first phase delay layer 4 is located between the display component 1 and the optical path folding component 5 .

[0084] Among them, 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 output, that is, the first phase delay layer 4 is a quarter-wave plate. The first phase delay layer 4 is set to meet the requirements of the optical path folding component 5 for the polarization state of the incident light.

[0085] The optical path returning component 5 is used to reflect circularly polarized light multiple times and convert it into linearly polarized light for output. The multiple reflections of light in the optical path returning component 5 can effectively reduce the thickness of the device, achieve a lightweight design, and reduce the weight and volume of the near-eye display device, thereby improving wearing comfort. At the same time, it also has the effect of improving edge imaging quality and reducing image distortion.

[0086] Specifically, the optical path return component 5 may include a partially reflective and partially transmissive layer 51, a second phase retarder 52, and a reflective polarizer 53, which are sequentially arranged away from the first phase retarder 4. The second phase retarder 52 is configured to retard the phase of the incident light by π / 2, i.e., the second phase retarder 52 is a quarter-wave plate. The reflective polarizer 53 is configured 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 component 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 is partially transmitted to the second phase retardation layer 52, and is converted by the second phase retardation layer 52 into a first linear polarized light L1 and is emitted to the reflective polarizer 53, the reflective polarizer 53 reflects the first linear polarized light L1 to the second phase retardation layer 52, the second phase retardation layer 52 converts the first linear polarized light L1 into a 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 causes part of the circularly polarized light to be reflected by the partially reflective and partially transmissive layer 51 to the second phase retardation layer 52, and converts the part of the circularly polarized light into a 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 a second linear polarized light L2 and emits it to the reflective polarizer 53, and the reflective polarizer 53 transmits the second linear polarized light L2 and emits it.

[0088] In some embodiments, the light path folding component 5 may further include a second linear polarizer 54, which is located on the light output path of the reflective polarizer 53 and is used to pass the second linear polarized light L2. The reflective polarizer 53 is emitted to the second linear polarizer 54 to ensure that the light emitted by the light path folding component 5 is the second linear polarized light L2.

[0089] The positions of the first phase retarder layer 4 and the optical path bending assembly 5 in the near-eye display device can also be configured according to specific needs. For example, as shown in Figure 11, the zoom assembly 2 can be located on the light output path of the optical path bending assembly 5, so that the second linearly polarized light L2 emitted by the optical path bending assembly 5 is incident on the zoom assembly 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 first linearly polarized light L1, which is then focused at the first focal length f1 after passing through the liquid crystal lens 22.

[0090] FIG12 is a schematic structural diagram of another near-eye display device provided in an embodiment of the present disclosure.

[0091] As shown in Figure 12, in the embodiment of the present disclosure, the zoom component 2 can be located between the display component 1 and the first phase delay layer 4. From the principle of the above-mentioned optical path returning component 5, it can be seen that the light incident on the optical path returning component 5 needs to be the first linear polarized light L1. Therefore, the near-eye display device also includes a second liquid crystal polarization rotator 6. The second liquid crystal polarization rotator 6 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 returning component 5 meets the requirements.

[0092] As shown in FIG12(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 a first focal length f1 after passing through the liquid crystal lens 22. Similarly, when no voltage is applied to the second liquid crystal polarization rotator 6, the second liquid crystal polarization rotator 6 emits first linearly polarized light L1, which is converted to second linearly polarized light L2 after passing through the first phase retarder 4 and the optical path bending component 5. As shown in FIG12(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 a second focal length f2 after passing through the liquid crystal lens 22. Similarly, when a voltage is applied to the second liquid crystal polarization rotator 6, the second liquid crystal polarization rotator 6 converts the second linearly polarized light L2 into first linearly polarized light L1, which is then converted to second linearly polarized light L2 after passing through the first phase retarder 4 and the optical path bending component 5.

[0093] To further help understand the zoom principle of the zoom assembly 2 provided in the embodiment of the present disclosure, the specific structures of the first liquid crystal polarization rotator 21 and the liquid crystal lens 22 in the zoom assembly 2 are described below.

[0094] FIG13 is a schematic structural diagram of a first liquid crystal polarization rotator provided in an embodiment of the present disclosure.

[0095] As shown in FIG13 , the first liquid crystal polarization rotator 21 may include a first liquid crystal layer 211 , with orientation layers 212 disposed on both sides of the first liquid crystal layer 211 , an electrode layer 213 disposed on the side of each orientation layer 212 facing away from the first liquid crystal layer 211 , and a substrate 214 disposed on the side of each electrode layer 213 facing away from the orientation layer 212 . By controlling the electrical signal applied to the electrode layer 213 , the deflection of the liquid crystal molecules in the first liquid crystal layer 211 can be controlled, thereby controlling the light emitted from the first liquid crystal polarization rotator 21 to switch between the first linearly polarized light and the second linearly polarized light.

[0096] FIG. 14 is a dispersion characteristic curve diagram of the first liquid crystal polarization rotator corresponding to FIG. 13 .

[0097] FIG14 shows the stray light ratio of light of different wavelengths after exiting the first liquid crystal polarization rotator 21 shown in FIG13 , both in the powered and unpowered states. The abscissa represents the wavelength in nanometers (nm), and the ordinate represents the percentage of stray light in the exiting light. As shown in FIG14 , 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 light exiting the first liquid crystal polarization rotator 21 contains a high amount of stray light in the red wavelength range (610nm-730nm) and the blue wavelength range (400nm-500nm). This is because the first liquid crystal polarization rotator 21 is relatively thick, and during the manufacturing process, the liquid crystal molecules are not fully aligned, resulting in some liquid crystal molecules having different deflection angles than others. When 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 light exiting the first liquid crystal polarization rotator 21 contains substantially no stray light. It can be seen that if the thickness of the first liquid crystal layer 211 is too large, it may cause stray light in the light emitted by the first liquid crystal polarization rotator 21 , causing dispersion in the image and affecting the image quality to a certain extent.

[0098] FIG15 is a schematic structural diagram of another first liquid crystal polarization rotator provided in an embodiment of the present disclosure.

[0099] As shown in (a) of Figure 15, the first liquid crystal polarization rotator 21 may include two first liquid crystal layers 211, with orientation layers 212 disposed on both sides of each first liquid crystal layer 211, an electrode layer 213 disposed on the side of each orientation layer 212 facing away from the first liquid crystal layer 211, and a substrate 214 disposed on the side of each electrode layer 213 facing away from the orientation layer 212. By controlling the electrical signal applied to each electrode layer 213, the rotation of the 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, controlling the switching of light emitted by the first liquid crystal polarization rotator 21 between first linearly polarized light and second linearly polarized light.

[0100] As shown in FIG. 15( b ), the two first liquid crystal layers 211 may share the same electrode layer 213 , so as to simplify the manufacturing process of the first liquid crystal polarization rotator 21 and reduce the thickness of the first liquid crystal polarization rotator 21 .

[0101] FIG. 16 is a dispersion characteristic curve diagram of the first liquid crystal polarization rotator corresponding to FIG. 15 .

[0102] FIG16 shows the stray light ratios of light of different wavelengths after exiting the first liquid crystal polarization rotator 21 shown in FIG15 , both in the powered and unpowered states. The horizontal axis represents the wavelength in nanometers (nm), and the vertical axis represents the percentage of stray light in the exiting light. As shown in FIG16 , when the first liquid crystal polarization rotator 21 includes two first liquid crystal layers 211, the stray light ratio in the exiting light of the first liquid crystal polarization rotator 21 is low, regardless of whether a voltage is applied to the first liquid crystal layers 211 or not.

[0103] In the disclosed embodiment, the first liquid crystal polarization rotator 21 includes two first liquid crystal layers 211 that cooperate to achieve the function of a half-wave plate. Each first liquid crystal layer 211 can have a relatively small thickness. This improves the response speed of each first liquid crystal layer 211 and allows for more complete alignment of the liquid crystal molecules within the first liquid crystal layers 211 during fabrication. This helps reduce the proportion of stray light in the light emitted by the first liquid crystal polarization rotator 21, improves the dispersion of the image, and enhances image quality.

[0104] It is understood that the first liquid crystal polarization rotator 21 may further include more first liquid crystal layers 211, arranged sequentially along the optical path. The thickness of each first liquid crystal layer 211 may be further reduced, thereby facilitating improved response speed of the first liquid crystal polarization rotator 21. Electrode layers 213 are provided on both sides of each first liquid crystal layer 211, or at least two adjacent first liquid crystal layers 211 may share the same electrode layer 213, or every two adjacent first liquid crystal layers 211 may 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 based on specific needs and is not limited herein.

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

[0106] FIG17 is a schematic structural diagram of a liquid crystal lens provided in an embodiment of the present disclosure.

[0107] As shown in FIG17 , in the 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 FIG17 (a), the light incident surface 2201 of the second liquid crystal layer 221 can be set as a curved surface, and the light emitting surface 2202 can be set as a flat surface. Alternatively, as shown in FIG17 (b), the light incident surface 2201 of the second liquid crystal layer 221 can be set as a flat surface, and the light emitting surface 2202 can be set as a curved surface. Alternatively, as shown in FIG17 (c), both the light incident surface 2201 and the light emitting surface 2202 of the second liquid crystal layer 221 can be set as curved surfaces. For example, the above-mentioned curved surfaces can be aspherical surfaces.

[0108] The liquid crystal lens 22 provided in the embodiment of the present disclosure is a solid-state liquid lens. It does not require the application of voltage to achieve imaging at 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 to a curved surface, at least some of the liquid crystal molecules therein can have different deflection directions. Based on the anisotropy of the liquid crystal material, linearly polarized light with different polarization directions can be focused at different focal lengths by the liquid crystal lens 22. 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, so it can achieve fast imaging.

[0109] The curvature radii of the light incident surface 2201 and the light emitting surface 2202 of the second liquid crystal layer 221, as well as the thickness of the second liquid crystal layer 221, can be designed based on specific needs and are not limited in the present 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, to ensure that the liquid crystal lens 22 can have good imaging quality.

[0110] FIG18 is a schematic structural diagram of another liquid crystal lens provided in an embodiment of the present disclosure.

[0111] As shown in FIG18 , in the disclosed embodiment, 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 each other, with the first alignment layer 224 located on the surface of the first substrate 222 facing the second substrate 223, and the second alignment layer 225 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 may be any of the three types of second liquid crystal layers 221 shown in FIG17 . 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 exit surface 2202 of the second liquid crystal layer 221. The materials and shapes of the first and second substrates 222, 223 are not limited herein and can be designed based on the required imaging focal length. In the 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, the embodiment of the present disclosure further provides a method for manufacturing a liquid crystal lens 22 . The manufacturing process of the liquid crystal lens 22 is described below by taking the structure of the liquid crystal lens 22 shown in FIG. 17 ( a ) as an example.

[0113] FIG19 is a schematic diagram of a manufacturing process of a liquid crystal lens provided in an embodiment of the present disclosure; FIG20 is a schematic diagram of a manufacturing process of another liquid crystal lens provided in an embodiment of the present disclosure.

[0114] As shown in FIG19 and FIG20 , the method for manufacturing the liquid crystal lens 22 may include the following steps:

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

[0116] Step S2: forming a second alignment layer 225 on the second substrate 223. For example, referring to FIG19(c) and FIG20(c), a flat glass is used as the second substrate 223, PI is coated on one 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 FIG19(d) and FIG20(d), the first substrate 222 can be aligned on top and the second substrate 223 on the bottom, and a spacer or a gasket T can be placed between the first substrate 222 and the second substrate 223 to control the thickness.

[0118] Step S4: Injecting 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 box for preheating, for example, to 80°C. An appropriate amount of curable liquid crystal is taken and heated to a clearing point. Then, referring to FIG19(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 FIG20(e), the liquid crystal can be injected between the first substrate 222 and the second substrate 223 by high-pressure injection.

[0119] Step S5: solidify the liquid crystal material to form the second liquid crystal layer 221. For example, referring to (f) and (g) in FIG. 19 and (f) and (g) in FIG. 20 , the device formed in step S4 can be placed on a heating platform for planarization and alignment. A strong electric field can also be applied to the liquid crystal for auxiliary alignment to achieve a better alignment effect. After alignment 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 FIG. 19(h) and FIG. 20(h), the first substrate 222 and the first alignment layer 224 thereon are removed, and the second substrate 223 and the second alignment layer 225 thereon are removed, thereby obtaining the liquid crystal lens 22 shown in FIG. 17(a). If the liquid crystal lens 22 shown in FIG. 18 is produced, step S6 is omitted.

[0121] Although the preferred embodiments of the present application have been described, those skilled in the art may make additional changes and modifications to these embodiments once they have learned the basic creative concept. Therefore, the appended claims are intended to be interpreted as including the preferred embodiments and all changes and modifications that fall within the scope of the present application.

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

Claims

1. A near-eye display device, wherein: The near-eye display device comprises: A display assembly for emitting linearly polarized light; A zoom component is located on the light output path of the display component; the zoom component includes: a first liquid crystal polarization rotator, configured to switch the incident linearly polarized light between a first linearly polarized light and a second linearly polarized light, 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; The liquid crystal lens is located on 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 by the first liquid crystal polarization rotator onto different focal lengths.

2. The near-eye display device according to claim 1, wherein: There are multiple zoom components, and the multiple zoom components are arranged in sequence along the light output path of the display component.

3. The near-eye display device according to claim 2, wherein: The plurality of zoom components are used to adjust the imaging picture of the display component between 2 and 2 n The zoom lens can switch between focal planes, wherein n is the number of the zoom components.

4. The near-eye display device according to 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 according to claim 2, wherein: The near-eye display device also includes an imaging lens group, which is located between the display component and the multiple zoom components, or the imaging lens group is located on the light output path of the multiple zoom components, or the imaging lens group is located between any two zoom components among the multiple zoom components.

6. The near-eye display device according to claim 4 or 5, wherein: The imaging lens assembly includes at least one imaging lens.

7. The near-eye display device according to claim 1, wherein: The near-eye display device also includes a first phase delay layer and an optical path folding component, wherein the first phase delay layer is located between the display component and the optical path folding component; the first phase delay layer is used to delay the phase of the incident linearly polarized light by π / 2 to convert it into circularly polarized light for output; the optical path folding component is used to reflect the circularly polarized light multiple times and convert it into linearly polarized light for output.

8. The near-eye display device according to claim 7, wherein: The zoom component is located on the light-outgoing path of the light-path folding component.

9. The near-eye display device according to claim 7, wherein: The zoom component is located between the display component and the first phase delay layer; the near-eye display device also includes a second liquid crystal polarization rotator, which is located between the zoom component and the first phase delay layer.

10. The near-eye display device according to any one of claims 7 to 9, wherein: The optical path folding component includes a partially reflective and partially transmissive layer, a second phase delay layer, and a reflective polarizer, which are arranged in sequence away from the first phase delay layer. The second phase delay layer is used to delay the phase of the incident light by π / 2, and the reflective polarizer is used to reflect the first linear polarized light and transmit the second linear polarized light.

11. The near-eye display device according to any one of claims 1 to 10, wherein: The first liquid crystal polarization rotator includes at least one first liquid crystal layer. 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 according to claim 11, wherein: At least two adjacent first liquid crystal layers share the same electrode layer.

13. The near-eye display device according to claim 11, wherein: The first liquid crystal layer is one of electrically controlled birefringence liquid crystal, vertical alignment liquid crystal or optically compensated bend liquid crystal.

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

15. The near-eye display device according to claim 14, wherein: 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 arranged opposite to each other. The first alignment layer is located on a surface of the first substrate facing the second substrate, and the second alignment layer is located on a surface of the second substrate facing the first substrate. The surface on which the first alignment layer and / or the second alignment layer are located is a curved surface. The second liquid crystal layer is located between the first alignment layer and the second alignment layer.

16. The near-eye display device according to claim 15, wherein: The curved surface is an aspherical surface.

17. The near-eye display device according to 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 method for controlling a near-eye display device according to any one of claims 1 to 17, wherein: The control method includes: The output light of the first liquid crystal polarization rotator is controlled to switch between first linearly polarized light and second linearly polarized light according to depth information of an 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 according to claim 18, wherein: The step of controlling the output light of the first liquid crystal polarization rotator to switch between the first linear polarized light and the second linear polarized light according to the depth information of the image to be displayed by the display component comprises: When the depth information of the displayed image is less than or equal to a preset threshold, controlling the first liquid crystal polarization rotator 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 according to claim 18, wherein: The control method further includes: The display component is controlled to sequentially display images with the same picture but different brightness in two consecutive frames, and the first liquid crystal polarization rotator is controlled to respectively emit the first linearly polarized light and the second linearly polarized light in the two consecutive frames.

Images