Composite liquid crystal lens, preparation method, display device and display method

Abstract

This application discloses a composite liquid crystal lens, a fabrication method, a display device, and a display method. The composite liquid crystal lens includes a first liquid crystal lens and a second liquid crystal lens stacked together. The first liquid crystal lens is configured to deflect incident light of different wavelengths in a specific direction by changing the refractive index of the liquid crystal within it. The second liquid crystal lens is configured to deflect incident light of different wavelengths in a specific direction by changing the phase of the liquid crystal within it. The second liquid crystal lens compensates for the light transmitted through the first liquid crystal lens, or vice versa, so that light of different wavelengths transmitted through the composite liquid crystal lens is focused or nearly focused at the same position. The composite liquid crystal lens provided in this application effectively solves the wavelength dependence of different lenses, reduces dispersion, and achieves better display effects.

Description

Technical Field

[0001] This application generally relates to the field of display technology, and specifically to a composite liquid crystal lens, a preparation method, a display device, and a display method. Background Technology

[0002] Traditional 2D displays can only provide psycho-visual information related to affine projection, occlusion, lighting and shadow, texture, and prior knowledge. Light field displays, in addition to providing all the information of traditional 2D displays, can also provide physiological visual information related to binocular parallax, motion parallax, and focus blur. Light field displays can also produce different colors depending on the viewing angle. This is the most fundamental aspect of holographic imaging technology.

[0003] Currently, AR / VR light field display technology and naked-eye 3D technology are the most cutting-edge technologies in the display field and are also hot topics of interest for various companies. Both AR / VR light field display and naked-eye 3D display technologies require light guide technology and lens technology to modulate the image onto the human eye, achieving a wider viewing angle, increased brightness, and better image data superposition and processing to achieve better display effects. Summary of the Invention

[0004] In view of the above-mentioned defects or deficiencies in the prior art, it is desirable to provide a composite liquid crystal lens, a preparation method, a display device, and a display method that can reduce dispersion and achieve better display effects.

[0005] In a first aspect, this application provides a composite liquid crystal lens, comprising a first liquid crystal lens and a second liquid crystal lens stacked together, wherein...

[0006] The first liquid crystal lens is configured to deflect incident light of different wavelengths in a specific direction by means of the change in the refractive index of the liquid crystal in the first liquid crystal lens.

[0007] The second liquid crystal lens is configured to deflect incident light of different wavelengths in a specific direction by changing the phase of the liquid crystal in the second liquid crystal lens;

[0008] The light transmitted through the first liquid crystal lens is compensated by the second liquid crystal lens, or the light transmitted through the second liquid crystal lens is compensated by the first liquid crystal lens, so that light of different wavelengths transmitted through the composite liquid crystal lens is focused or nearly focused at the same position.

[0009] Optionally, the first liquid crystal lens is configured to have a larger focal length as the wavelength of the incident light increases.

[0010] Optionally, the second liquid crystal lens is configured such that its focal length decreases as the wavelength of the incident light increases.

[0011] Furthermore, the liquid crystal molecules of the second liquid crystal lens are arranged in their initial state when there is no bias voltage, and the orientation of the liquid crystal molecules is modulated under the same bias voltage. The orientation angle of the liquid crystal molecules compensates for the phase of the light transmitted through the first liquid crystal lens.

[0012] Furthermore, the orientation vector of the liquid crystal molecules in the second liquid crystal lens in the initial state is 0 degrees to 180 degrees.

[0013] Specifically, the first liquid crystal lens includes a first liquid crystal layer, and a first electrode and a second electrode disposed on both sides of the first liquid crystal layer, wherein at least one of the first electrode and the second electrode is a block electrode.

[0014] Optionally, the liquid crystal material of the first liquid crystal layer is a nematic liquid crystal, ferroelectric liquid crystal, antiferroelectric liquid crystal, subferroelectric liquid crystal, or cholesteric liquid crystal.

[0015] Specifically, the second liquid crystal lens includes a second liquid crystal layer and a third electrode and a fourth electrode disposed on both sides of the second liquid crystal layer, wherein at least one of the third electrode and the fourth electrode is a planar electrode.

[0016] Furthermore, the second liquid crystal lens also includes an alignment layer disposed between the third electrode and the second liquid crystal layer or between the fourth electrode and the second liquid crystal layer, the alignment layer being configured to arrange the liquid crystal molecules in an initial state when there is no bias voltage.

[0017] Secondly, this application provides a method for fabricating a composite liquid crystal lens, used to fabricate a composite liquid crystal lens as described in any of the above claims, comprising:

[0018] Fabrication of the first liquid crystal lens;

[0019] A second liquid crystal lens is fabricated on the first liquid crystal lens;

[0020] The fabrication of the second liquid crystal lens includes:

[0021] Indium tin oxide conductive glass is provided as the surface electrode substrate;

[0022] The alignment layer is prepared by spin-coating polyimide onto a surface electrode substrate and then preparing the alignment layer by laser interference exposure.

[0023] A second liquid crystal layer is prepared on the alignment layer.

[0024] Thirdly, this application provides a display device including a composite liquid crystal lens as described in any of the above claims.

[0025] Optionally, the display device is a glasses-free 3D display device.

[0026] Fourthly, this application provides a display method for a display device, the method comprising:

[0027] Apply and adjust a voltage to the first liquid crystal lens to obtain the focal length of the first liquid crystal lens;

[0028] Based on the focal length of the first liquid crystal lens, a voltage is applied to and adjusted on the second liquid crystal lens;

[0029] By adjusting the voltage of the second liquid crystal lens, the orientation angle of the liquid crystal molecules in the second liquid crystal lens is adjusted to perform phase compensation on the light entering the second liquid crystal lens.

[0030] A 3D display effect is achieved by modulating the light through the second liquid crystal lens.

[0031] The technical solutions provided by the embodiments of this application may include the following beneficial effects:

[0032] The composite liquid crystal lens provided in this application can solve the chromatic dispersion phenomenon caused by the wavelength dispersion problem when the first liquid crystal lens and the second liquid crystal lens are used separately. Furthermore, the focusing ability of the composite lens can be superimposed, enabling the liquid crystal lens to have a greater focal length adjustment capability. It effectively solves the dependence of different lenses on wavelength, reduces chromatic dispersion, and achieves better display effect. Attached Figure Description

[0033] Other features, objects, and advantages of this application will become more apparent from the following detailed description of non-limiting embodiments with reference to the accompanying drawings:

[0034] Figure 1 A schematic diagram of the structure of a composite liquid crystal lens provided for an embodiment of this application;

[0035] Figure 2 A schematic diagram illustrating the display principle of the first liquid crystal lens provided for an embodiment of this application;

[0036] Figure 3 A schematic diagram of the light rays from a first liquid crystal lens provided for an embodiment of this application;

[0037] Figure 4 A schematic diagram illustrating the display principle of the second liquid crystal lens provided for embodiments of this application;

[0038] Figure 5 A schematic diagram of the light rays from a second liquid crystal lens provided for an embodiment of this application;

[0039] Figure 6 A schematic diagram of the distribution of liquid crystal molecules in the second liquid crystal lens in the initial state, provided for an embodiment of this application;

[0040] Figure 7 A schematic diagram of the distribution of liquid crystal molecules in a second liquid crystal lens provided in an embodiment of this application when a voltage is applied;

[0041] Figure 8 A schematic diagram of the light rays of a composite liquid crystal lens provided for an embodiment of this application;

[0042] Figure 9 A flowchart illustrating a display method of a display device provided in an embodiment of this application. Detailed Implementation

[0043] The present application will now be described in further detail with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the invention and not intended to limit it. Furthermore, it should be noted that, for ease of description, only the parts relevant to the invention are shown in the accompanying drawings.

[0044] It should be noted that, unless otherwise specified, the embodiments and features described in this application can be combined with each other. This application will now be described in detail with reference to the accompanying drawings and embodiments.

[0045] Currently, the main lens technologies used are solid-state lenses and liquid crystal lenses. Compared with solid-state lenses, liquid crystal lenses have a series of advantages: variable focus, small size, thinness, light weight, and long lifespan. Furthermore, liquid crystal lens technology, due to its adjustable electric field, adjustable focal length, and high integration with panel technology, has become a hot research topic and is considered the most promising technological direction. Of course, liquid crystal lens technology is also more challenging.

[0046] Liquid crystal lenses (LCDs) can change their focal position within tens of milliseconds. Because LCDs change their focal length without mechanical movement, they have enormous application potential in many fields, including surveillance, beam shaping and steering, illumination, adaptive optics, and medical imaging. Currently, LCDs, as devices that change their focal position through an applied voltage, are widely used in the display field, and are particularly suitable for portable devices such as 3D displays, mobile phone imaging systems, wearable displays, VR devices, and light field displays.

[0047] With the development of high PPI technology, light field display technology and naked-eye 3D technology have become research hotspots, and light field and naked-eye 3D technologies with practical application value are getting closer and closer to mass production.

[0048] Currently, the light field and naked-eye 3D technology closest to mass production is the cylindrical lens multi-viewpoint technology. Cylindrical lens technology generally uses solid lens technology, but solid lens technology cannot achieve zoom function; while liquid crystal lens technology has better technical effect and has strong application prospects. At present, refractive index liquid crystal lens technology is an important technical direction of liquid crystal lens technology because it has good compatibility with LCD process and the voltage is adjustable.

[0049] However, different wavelengths of light in liquid crystal devices have different refractive indices. In flat panel displays, the effect of wavelength refractive index variation does not significantly affect display quality, but it has a significant impact on liquid crystal lens technology. Therefore, an important issue with refractive index liquid crystal lenses is wavelength dependence, that is, different wavelengths of light have different focal lengths in the liquid crystal lens.

[0050] Please see details. Figure 1 This application provides a composite liquid crystal lens, including a first liquid crystal lens 1 and a second liquid crystal lens 2 stacked together, wherein...

[0051] The first liquid crystal lens 1 is configured to deflect incident light of different wavelengths in a specific direction by means of the change in the refractive index of the liquid crystal in the first liquid crystal lens 1.

[0052] The second liquid crystal lens 2 is configured to deflect incident light of different wavelengths in a specific direction by changing the phase of the liquid crystal in the second liquid crystal lens 2.

[0053] The light transmitted through the first liquid crystal lens 1 is compensated by the second liquid crystal lens 2, or the light transmitted through the second liquid crystal lens 2 is compensated by the first liquid crystal lens 1, so that light of different wavelengths transmitted through the composite liquid crystal lens is focused or nearly focused at the same position.

[0054] It should be noted that, in the embodiments of this application, the arrangement of the first and second liquid crystal lenses can include either the first liquid crystal lens being located on the light-emitting side of the composite liquid crystal lens along the optical path, or the second liquid crystal lens being located on the light-emitting side of the composite liquid crystal lens along the optical path. Regardless of the arrangement, the phase relationship or focal length relationship between the first and second liquid crystal lenses allows the latter to compensate for the light transmitted through the former, thus achieving focusing or near-focusing of light of different wavelengths transmitted through the composite liquid crystal lens at the same position.

[0055] In this embodiment of the application, the first liquid crystal lens 1 includes a first liquid crystal layer 10, and a first electrode 11 and a second electrode 12 disposed on both sides of the first liquid crystal layer 10, wherein at least one of the first electrode 11 and the second electrode 12 is a block electrode.

[0056] The specific shape of the block electrode is not limited; for example, it can be a square block electrode, a circular block electrode, or a triangular block electrode, etc. The position of the liquid crystal layer on the liquid crystal lens plate is not adjustable; the focal length of the equivalent unit of the lens can be adjusted by adjusting the voltage of the block electrode in the electrode unit.

[0057] The liquid crystal material of the first liquid crystal layer 10 is a nematic liquid crystal, ferroelectric liquid crystal, antiferroelectric liquid crystal, subferroelectric liquid crystal, or cholesteric liquid crystal. The first liquid crystal lens 1 is configured such that its focal length increases with the increase of the incident light wavelength.

[0058] like Figure 2 As shown in Figure a, the display principle of the first liquid crystal lens 1 is as follows: When no power is applied, polarized light propagates along the light path shown in the figure, and no phase difference is generated within the lens aperture (Pitch), thus no lens effect is produced. When power is applied, as... Figure 2 As shown in Figure b, polarized light propagates along the light ray indicated in the figure. Different effective refractive indices are achieved at different positions of the lens aperture (Pitch) through the electrodes. Therefore, parallel light has different phase differences at different positions of the lens aperture (Pitch), producing a lens focusing effect. That is, the parabolic distribution of the liquid crystal refractive index is achieved through the distribution of the electric field, thus realizing the lens effect.

[0059] The formula for the focal length / focal power of the first liquid crystal lens 1 is as follows:

[0060]

[0061] Where f1 is the focal length of the first liquid crystal lens 1, r0 is the aperture (pitch) of the first liquid crystal lens 1, and n c n is the refractive index at the center of the first liquid crystal lens 1. b d is the refractive index at the edge of the first liquid crystal lens 1, and d is the thickness of the first liquid crystal lens 1.

[0062] As can be seen from the formula, the focal power / focal length of the first liquid crystal lens 1 is related to the refractive index; and different wavelengths of light in a liquid crystal device have different refractive indices:

[0063] n=sinθ / sinθ′=n′ / n=c / v

[0064] That is, the refractive index is equal to the ratio of the speed of light c in a vacuum to the phase velocity v in a medium.

[0065] However, the refractive index of light decreases as the wavelength increases; n1 / n2 = λ2 / λ1.

[0066] Therefore, an important issue is wavelength dependence, such as Figure 3 As shown, different wavelengths of light have different focal lengths in the liquid crystal lens, and the first liquid crystal lens 1 is configured to increase the focal length as the wavelength of the incident light increases.

[0067] For example, the retardation difference Δnd corresponding to the visible light range is 500 to 1200 nm; the focal length difference generated in the visible light range can be calculated to be 0.1 to 0.2 mm, that is, the focal length deviation is greater than 10%.

[0068] In this embodiment, the second liquid crystal lens 2 is a phase difference type liquid crystal lens, employing the PB (Pancharatnam-Berry) phase modulation principle. The Pancharatnam-Berry phase is a geometric phase related to the polarization of light. As early as 2002, Israeli scientists Bomzon et al. proved that PB-phase optical devices based on subwavelength gratings could achieve any desired phase. Subsequently, Erez Hasman's team used the PB phase to realize a focusing lens for circularly polarized light. L. Marrucci et al. fabricated PB-phase-based optical devices for wavefront shaping. Lin et al. at Stanford University used the PB phase principle to fabricate a dielectric metasurface suitable for circularly polarized light incidence, realizing the functions of optical devices such as half-wave plates, prisms, and lenses. The PB phase allows for very simple realization of the desired phase, thus making it easier to achieve light manipulation.

[0069] Specifically, the second liquid crystal lens 2 includes a second liquid crystal layer 20 and a third electrode 21 and a fourth electrode 22 disposed on both sides of the second liquid crystal layer 20, wherein at least one of the third electrode 21 and the fourth electrode 22 is a planar electrode.

[0070] The liquid crystal molecules of the second liquid crystal lens 2 are arranged in their initial state when there is no bias voltage, and the orientation of the liquid crystal molecules is modulated under the same bias voltage. The orientation angle of the liquid crystal molecules compensates for the phase of the light transmitted through the first liquid crystal lens 1.

[0071] The principle behind this technique is to modulate incident light using a liquid crystal metasurface structure, creating a phase difference and thus forming a lens focusing effect. The second liquid crystal lens 2 is configured such that its focal length decreases as the wavelength of the incident light increases.

[0072] The principle behind this technique is to modulate incident light using a liquid crystal metasurface structure, creating a phase difference and thus forming a lens focusing effect. The second liquid crystal lens 2 is configured such that its focal length decreases as the wavelength of the incident light increases.

[0073] like Figure 4 As shown, according to the generalized Snell's law:

[0074]

[0075] Where, θ i Let θ be the angle of incidence. tΦ is the emission angle, n is the refractive index of the liquid crystal lens, Φ is the phase of the emitted light, and x is the optical path length of the critical surface.

[0076] like Figure 5 As shown, assuming the incident angle θ i If the value is 0, then the focal length as a function of wavelength can be obtained as follows:

[0077]

[0078] At this point, the orientation angle of the liquid crystal molecules and the phase of the emitted light can be expressed as:

[0079]

[0080] Where Φ is the phase of the emitted light, θ is the orientation angle of the liquid crystal molecules, λ0 is the wavelength of the incident light, r is the aperture (Pitch) of the second liquid crystal lens 2, and f is the focal length of the second liquid crystal lens 2.

[0081] Therefore, the focal length of the second liquid crystal lens 2 can be approximated as:

[0082]

[0083] Where f0 is the focal length of the lens corresponding to the wavelength λ0 of the incident light, and Δλ is the change in wavelength of the incident light.

[0084] As shown in the above formula, the focal length of the second liquid crystal lens 2 decreases as the wavelength increases. That is, the second liquid crystal lens 2 also exhibits wavelength-focal-length dependence, resulting in wavelength dispersion; moreover, the focal length decreases as the wavelength increases. For example, for a visible light wavelength change of approximately 0.1 mm, the focal length is approximately 0.8–0.9 mm.

[0085] In this embodiment, the focal lengths of the first liquid crystal lens 1 and the second liquid crystal lens 2 are matched. The focal length of the first liquid crystal lens 1 increases with the increase of the incident light wavelength, while the focal length of the second liquid crystal lens 2 decreases with the increase of the incident light wavelength. By matching the opposite transformation methods of the focal lengths of the first liquid crystal lens 1 and the second liquid crystal lens 2 for different incident light wavelengths, the second liquid crystal lens 2 exhibits a small phase change for incident light with longer wavelengths and a large phase change for incident light with shorter wavelengths, allowing outgoing light of different wavelengths to be focused or nearly focused at the same focal length position.

[0086] Additionally, the second liquid crystal lens 2 further includes an alignment layer 23 disposed between the third electrode 21 and the second liquid crystal layer 20 or between the fourth electrode 22 and the second liquid crystal layer 20. The alignment layer 23 is configured to arrange the liquid crystal molecules in their initial state when there is no bias voltage. For example... Figure 6As shown, the orientation vector of the liquid crystal molecules in the second liquid crystal lens 2 in the initial state is 0 degrees to 180 degrees.

[0087] It should be noted that, Figure 6 and Figure 7 The illustration shows the arrangement of liquid crystal molecules in the second liquid crystal lens. In other applicable scenarios, the liquid crystal molecules can also be arranged in other ways. Different arrangements will affect the refractive index and focal length of the second liquid crystal lens. Similarly, when a voltage is applied, the liquid crystal molecules will rotate, forming different orientation angles. This embodiment does not limit this. The phase compensation and focal length of the second liquid crystal lens need to be adjusted accordingly based on the focal length of the first liquid crystal lens.

[0088] In this application, the orientation of the liquid crystal molecules in their initial state is set to 0 to 180 degrees. When a voltage is applied to the second liquid crystal lens 2, the liquid crystal molecules can deflect their optical axis angle. Without an applied voltage, the liquid crystal molecules are distributed according to their initial state; as the voltage between the transparent electrodes gradually increases, the liquid crystal molecules deflect, and their alignment changes accordingly. Figure 7 As shown. It should be noted that, in this embodiment, the second liquid crystal lens 2 also functions as a lens to focus incident light when no electric field is applied. When an electric field is applied, the liquid crystal rotates to change the refractive index, thereby performing phase compensation for the incident light.

[0089] In this embodiment, the sign of the phase of the second liquid crystal lens 2 depends on the polarization chirality of the incident field. By controlling the angle of the local optical axis of the liquid crystal structure in the second liquid crystal lens 2, the desired phase can be obtained. Therefore, as long as the metasurface structure can be dynamically rotated, flexible phase control can be achieved.

[0090] It should be noted that, in the embodiments of this application, the focusing capability of the composite liquid crystal lens is achieved by superimposing the focal lengths of the first liquid crystal lens 1 and the second liquid crystal lens 2, which can be expressed as:

[0091]

[0092] Where f1 is the focal length of the first liquid crystal lens 1 and f2 is the focal length of the second liquid crystal lens 2.

[0093] The first liquid crystal lens 1 has a focal length of 1.0 mm, the second liquid crystal lens 2 has a focal length of 0.8 mm, and the composite lens has a focal length of 0.45 mm.

[0094] The focal length of the first liquid crystal lens 1 is 0.5 to 1.0 mm, and the focal length of the second liquid crystal lens 2 is 0.8 mm or infinite. Therefore, the focal length of the composite lens is 0.24 to 1.0 mm, and the power is 1 to 4.25. Thus, the composite lens has a larger focal length adjustment range and power, and stronger lens capability.

[0095] However, during zooming, the focal length dispersion matching capability decreases, and the compensation of the second liquid crystal lens 2 for the different wavelength focal length differences of the first liquid crystal lens 1 becomes smaller. In specific applications, the first liquid crystal lens 1 and the second liquid crystal lens 2 can be adapted according to different focal length requirements. While meeting the focal length requirements of the composite lens, better dispersion compensation can be achieved, such as... Figure 8 As shown.

[0096] Secondly, this application provides a method for fabricating a composite liquid crystal lens, used to fabricate a composite liquid crystal lens as described in any of the above claims, comprising:

[0097] S01. Fabrication of the first liquid crystal lens 1: In the specific fabrication process, a substrate with ITO electrodes is fabricated, and the parameters of the ITO electrodes are designed according to the requirements for forming a parabolic liquid crystal delay. Liquid crystal processing is used to fabricate liquid crystal cells with high refractive index droplets. The first liquid crystal lens 1 forms a delay difference in the liquid crystal by applying different voltages to the electrodes, thus forming a lens-shaped liquid crystal distribution.

[0098] S02. Fabricate a second liquid crystal lens 2 on the first liquid crystal lens 1. In this embodiment, the second liquid crystal lens 2 can be fabricated separately and then bonded to the surface of the first liquid crystal lens 1 by a bonding process, or it can be fabricated directly on the surface of the second liquid crystal lens 2. This application does not impose any restrictions on this.

[0099] The fabrication of the second liquid crystal lens 2 includes:

[0100] S201. Provide indium tin oxide conductive glass as a surface electrode substrate; in this application, a substrate with ITO electrodes is selected, and surface electrodes are generally used.

[0101] S202. Preparation of alignment layer 23 includes spin-coating polyimide onto a surface electrode substrate and preparing the alignment layer 23 by laser interference exposure.

[0102] S203. A second liquid crystal layer 20 is prepared on the alignment layer 23, for example, by using an ODF process.

[0103] The second liquid crystal lens 2 is very similar to the LCD process, the difference being that the alignment technology uses laser interference exposure technology instead of the traditional rubbing alignment or photoalignment technology; because laser interference exposure technology is more likely to form metasurface alignment morphology.

[0104] Thirdly, this application provides a display device including a composite liquid crystal lens as described in any of the above claims.

[0105] The specific type of display device is not limited; it can be a 2D display device, a privacy display device, a glasses-free 3D display device, a holographic display device, or a display device requiring localized light energy enhancement, etc. For example, when the display device is a glasses-free 3D display device, the collimated light is modulated after passing through the equivalent units of each lens to be directed towards the viewer's left and right visual areas, thereby achieving glasses-free 3D display. As another example, when the display device is a privacy display device, the collimated light is modulated to a very small viewing angle after passing through the equivalent units of each lens, so that only the viewer directly in front of the screen can see the display, while those in other positions cannot see the display.

[0106] Fourthly, such as Figure 8-9 As shown, this application provides a display method for a display device, the method comprising:

[0107] ST01. Apply and adjust voltage to the first liquid crystal lens 1 to obtain the focal length of the first liquid crystal lens 1;

[0108] ST02. Based on the focal length of the first liquid crystal lens 1, apply and adjust the voltage to the second liquid crystal lens 2;

[0109] ST03. By adjusting the voltage of the second liquid crystal lens 2, the orientation angle of the liquid crystal molecules in the second liquid crystal lens 2 is adjusted to perform phase compensation on the light entering the second liquid crystal lens 2.

[0110] ST04. A 3D display effect is achieved by modulating the light through the second liquid crystal lens 2.

[0111] In the electromagnetic field simulation design, the liquid crystal material properties and dimensional parameters (e.g., aperture and thickness) of the first liquid crystal lens 1 are first determined. Then, the voltage-to-transmission focal length relationship is obtained by applying a voltage. For the simulation of the liquid crystal lens, the liquid crystal pointing direction is set as the initial direction (unpowered state) to obtain the initial transmission phase matrix. The liquid crystal pointing direction is changed, and the voltage and transmission phase matrix are scanned successively. Based on the focal length of the first liquid crystal lens 1, suitable parameters for the second liquid crystal lens 2 are selected to satisfy the corresponding lens phase.

[0112] It should be understood that the terms "length", "width", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on the present invention.

[0113] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of this invention, "a plurality of" means two or more, unless otherwise explicitly specified.

[0114] Unless otherwise defined, the technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art. The terminology used herein is for descriptive purposes only and is not intended to limit the invention. Terms such as “set” appearing herein can refer to either a component being directly attached to another component or a component being attached to another component via an intermediary. A feature described in one embodiment herein may be applied, alone or in combination with other features, to another embodiment, unless that feature is not applicable in that other embodiment or is otherwise stated.

[0115] The present invention has been described through the above embodiments; however, it should be understood that the above embodiments are for illustrative purposes only and are not intended to limit the present invention to the described embodiments. Those skilled in the art will understand that many variations and modifications can be made based on the teachings of the present invention, and all such variations and modifications fall within the scope of protection claimed by the present invention.

Claims

1. A composite liquid crystal lens, characterized in that, It includes a first liquid crystal lens and a second liquid crystal lens stacked together, wherein, The first liquid crystal lens includes a first liquid crystal layer, and a first electrode and a second electrode disposed on both sides of the first liquid crystal layer, wherein at least one of the first electrode and the second electrode is a block electrode; the first liquid crystal lens is configured such that when no power is applied, the incident light does not produce a phase difference within the lens aperture; when power is applied, the change in the refractive index of the liquid crystal in the first liquid crystal lens is controlled by the block electrode to deflect incident light of different wavelengths in a specific direction, so that the focal length increases with the increase of the incident light wavelength; The focal length f1 of the first liquid crystal lens satisfies: r0 is the aperture of the first liquid crystal lens, n c n is the refractive index at the center of the first liquid crystal lens. b d is the refractive index at the edge of the first liquid crystal lens, and d is the thickness of the first liquid crystal lens; The second liquid crystal lens is a phase-difference type liquid crystal lens. The second liquid crystal lens includes a second liquid crystal layer, a third electrode and a fourth electrode disposed on both sides of the second liquid crystal layer, and an alignment layer disposed between the third electrode and the second liquid crystal layer or between the fourth electrode and the second liquid crystal layer. The alignment layer is configured to arrange the liquid crystal molecules in their initial state when there is no bias voltage. At least one of the third electrode and the fourth electrode is a planar electrode. The second liquid crystal lens is configured to deflect incident light of different wavelengths in a specific direction by changing the phase of the liquid crystal in the second liquid crystal lens, thereby achieving a decrease in focal length as the wavelength of the incident light increases. The focal length of the second liquid crystal lens satisfy: wavelength of the incident light The focal length of the lens corresponding to that time. This represents the change in wavelength of the incident light; The light transmitted through the first liquid crystal lens is compensated by the second liquid crystal lens, or the light transmitted through the second liquid crystal lens is compensated by the first liquid crystal lens, so that light of different wavelengths transmitted through the composite liquid crystal lens is focused or nearly focused at the same position.

2. The composite liquid crystal lens according to claim 1, characterized in that, The liquid crystal molecules of the second liquid crystal lens are arranged in their initial state when there is no bias voltage, and the orientation of the liquid crystal molecules is modulated under the same bias voltage. The orientation angle of the liquid crystal molecules compensates for the phase of the light transmitted through the first liquid crystal lens.

3. The composite liquid crystal lens according to claim 2, characterized in that, The orientation vector of the liquid crystal molecules in the second liquid crystal lens in the initial state is 0 degrees to 180 degrees.

4. The composite liquid crystal lens according to claim 1, characterized in that, The liquid crystal material of the first liquid crystal layer is a nematic liquid crystal, ferroelectric liquid crystal, antiferroelectric liquid crystal, subferroelectric liquid crystal, or cholesteric liquid crystal.

5. A method for preparing a composite liquid crystal lens, used to prepare the composite liquid crystal lens as described in any one of claims 1-4, characterized in that, include: Fabrication of the first liquid crystal lens; A second liquid crystal lens is fabricated on the first liquid crystal lens; The fabrication of the second liquid crystal lens includes: Indium tin oxide conductive glass is provided as the surface electrode substrate; The alignment layer is prepared by spin-coating polyimide onto a surface electrode substrate and then preparing the alignment layer by laser interference exposure. A second liquid crystal layer is prepared on the alignment layer.

6. A display device, characterized in that, Includes the composite liquid crystal lens as described in any one of claims 1-4.

7. The display device according to claim 6, characterized in that, The display device is a glasses-free 3D display device.

8. A display method based on the display device of claim 7, characterized in that, The method includes: Apply and adjust a voltage to the first liquid crystal lens to obtain the focal length of the first liquid crystal lens; Based on the focal length of the first liquid crystal lens, a voltage is applied to and adjusted on the second liquid crystal lens; By adjusting the voltage of the second liquid crystal lens, the orientation angle of the liquid crystal molecules in the second liquid crystal lens is adjusted to perform phase compensation on the light entering the second liquid crystal lens. A 3D display effect is achieved by modulating the light through the second liquid crystal lens.

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