Novel large-aperture liquid crystal cylindrical lens array

Abstract

The embodiment of the invention provides a novel large-aperture liquid crystal cylindrical lens array. The liquid crystal cylindrical lens array comprises an upper glass substrate, an upper transparent strip-shaped electrode, an upper orientation layer, a liquid crystal layer, a lower orientation layer, a central transparent strip-shaped electrode, a dielectric layer, a lower transparent strip-shaped electrode and a lower glass substrate which are sequentially arranged in the first direction. The upper transparent strip-shaped electrode is divided into two parts which are grounded to serve as a common electrode; the upper transparent strip-shaped electrode, the central transparent strip-shaped electrode and the lower transparent strip-shaped electrode jointly control liquid crystal molecules to rotate; when a voltage difference exists between the transparent strip-shaped electrodes, a liquid crystal cylindrical lens is formed in the liquid crystal layer. The invention has the advantages of simple structure, simple and convenient driving mode, low power consumption and the like, and can realize large-range focal length change.

Description

Technical Field

[0001] The present application relates to the display field, and in particular to a novel large-aperture liquid crystal column lens array. Background Art

[0002] As an important optical device, liquid crystal column lens arrays have shown great application potential in the fields of adaptive optics, optical communications, virtual reality (VR), augmented reality (AR), and 2D / 3D switchable display. Its main principle is to dynamically adjust the focal length by controlling the orientation change of liquid crystal molecules through voltage, so as to flexibly control the focusing, scattering or deflection of the incident light beam.

[0003] The main advantages of liquid crystal column lens arrays are its light weight, low power consumption and tunability. By applying different electric fields, its optical properties, such as focal length and phase distribution, can be quickly and accurately controlled without changing the physical structure of the lens. Compared with traditional mechanical or fixed focal length lenses, liquid crystal lenses can achieve real-time dynamic adjustment to adapt to a variety of scenarios and functional requirements, and are particularly suitable for integrated, high-density and miniaturized optical systems. In addition, the easy integration of liquid crystal devices enables them to be combined with a variety of optical components, further expanding their application range.

[0004] However, the development of liquid crystal lens arrays still faces many challenges. For example, although the liquid crystal lens with a multi-electrode structure can achieve complex phase control, its complex driving mode will cause electric field crosstalk, which in turn affects the imaging quality. The liquid crystal lens with a hole-shaped pattern electrode structure can achieve a large aperture, but due to the thick liquid crystal layer, the response time is correspondingly extended. Although the multi-layer liquid crystal lens has certain optical advantages, its light transmittance is limited, resulting in a decrease in image quality. In addition, although the optical hidden dielectric structure liquid crystal lens and the polymer-stabilized blue phase liquid crystal lens have advantages in phase control and response speed, they are still limited by the small adjustable focal length range. Summary of the invention

[0005] The example of the present application provides a novel large-aperture liquid crystal column lens array, which can overcome the defects existing in the prior art and has the advantages of simple structure, easy manufacturing, simple driving and wide focal length range.

[0006] The present application provides a novel large-aperture liquid crystal column lens array, comprising: upper glass substrate; An upper transparent strip electrode, disposed below the upper glass substrate, and used to serve as a common electrode for grounding; An upper alignment layer, disposed on the same layer as the upper transparent strip electrode, for providing a consistent initialization state for the liquid crystal molecules in the liquid crystal layer; a liquid crystal layer, disposed below the upper alignment layer; A lower alignment layer, disposed below the liquid crystal layer, for providing a consistent initialization state for liquid crystal molecules in the liquid crystal layer; A central transparent strip electrode is disposed on the same layer as the lower alignment layer and is used to provide an electric field to adjust the arrangement of the central liquid crystal molecules; A dielectric layer is provided below the central transparent strip electrode to separate the upper and lower strip electrodes, reduce the mutual interference of electric fields between the electrodes, and enhance the stability of the device; A lower transparent strip electrode is arranged on the same layer as the dielectric layer, and is used to apply voltage, provide an electric field, and adjust the arrangement of liquid crystal molecules; a lower glass substrate; The liquid crystal layer adopts a liquid crystal material with a positive dielectric constant, and the liquid crystal layer is vertically oriented relative to the long side of the transparent strip electrode.

[0007] The upper and lower transparent strip electrodes are plated on the inner surfaces of the upper and lower substrates respectively, and each electrode can be driven independently.

[0008] The upper transparent strip electrode is grounded as a common electrode, and voltage is applied to the lower transparent strip electrode and the central transparent strip electrode; dividing the common electrode into two parts can generate a non-uniform electric field, provide more precise control, and thus improve the arrangement of liquid crystal molecules.

[0009] Adding a central transparent strip electrode can further precisely control the local (central) electric field distribution, thereby improving the arrangement of liquid crystal molecules in the central part.

[0010] The refractive index of the liquid crystal molecules in the liquid crystal layer is:

[0011]

[0012] Where θ represents the angle between the incident light and the optical axis of the liquid crystal, n o and n e Represent the refractive indices of ordinary light and extraordinary light in the liquid crystal layer, respectively.

[0013] It should be noted that the present application provides a novel large-aperture liquid crystal column lens array, which exhibits properties similar to those of flat glass when no voltage is applied, and the liquid crystal molecules are evenly and orderly arranged under the action of the orientation layer, and the refractive index in the liquid crystal layer remains evenly distributed, and does not produce a converging effect on light. When a voltage is applied to the lower transparent strip electrode, the spatially non-uniform electric field generated between the upper transparent strip electrode and the lower transparent strip electrode as the ground will change the refractive index distribution inside the liquid crystal layer, and with the help of the regulation of the lower orientation layer, the refractive index distribution in the liquid crystal layer becomes parabolic.

[0014] Since a transparent strip electrode is placed in the central area of ​​the liquid crystal lens, this design reduces the driving voltage and realizes the ideal arrangement of liquid crystal molecules, greatly reducing energy consumption while simplifying the electric control process of the liquid crystal lens. Compared with the traditional liquid crystal lens, the present invention optimizes the electrode structure and the arrangement of liquid crystal molecules, so that the lens can achieve ideal focusing and defocusing effects at a lower voltage, further improving the performance and application potential of the liquid crystal lens. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Attached Figure 1 (a) and (b) are schematic diagrams of a novel large-aperture liquid crystal rod lens array structure before and after power is applied in the present application;

[0016] Attached Figure 2 is a schematic diagram of the distribution of liquid crystal molecules under a certain voltage applied in the present application;

[0017] Attached Figure 3 It is a schematic diagram of fitting the actual refractive index curve of the present application under applied voltage and the ideal nonlinear curve;

[0018] The diagram numbers in the above drawings are: 1 upper glass substrate, 2 upper transparent strip electrodes, 3 upper alignment layer, 4 liquid crystal layer, 5 lower alignment layer, 6 central transparent strip electrodes, 7 dielectric layer, 8 lower transparent strip electrodes, 9 lower glass substrate. DETAILED DESCRIPTION

[0019] In order to enable those skilled in the art to further understand the present application, the specific implementation of the present application will be described in detail below in conjunction with the accompanying drawings. It should be noted that the accompanying drawings are for illustration purposes only and are not drawn according to the original size ratio.

[0020] The liquid crystal material used in this embodiment is a nematic liquid crystal material.

[0021] The single electrode used in this embodiment is preferably made of indium tin oxide (ITO), the electrode thickness is greater than or equal to 0.01 μm, and the shape is a strip.

[0022] The dielectric layer used in this embodiment is made of a material with a high dielectric constant.

[0023] The rubbing directions of the upper and lower alignment layers used in this embodiment are both perpendicular to the long side directions of the transparent strip electrodes.

[0024] The liquid crystal molecules in the liquid crystal layer used in this embodiment are initially arranged perpendicular to the long side direction of the transparent strip electrodes, and the thickness of the liquid crystal layer is uniform.

[0025] The incident light wavelength λ used in this embodiment is 550nm, the widths of the upper transparent strip electrodes are w1 and w2, respectively, and the numerical difference is relatively large; the widths of the central transparent strip electrode and the lower transparent strip electrode are the same, namely w3=w4, both greater than 8μm; the lens aperture is greater than or equal to 500μm.

[0026] In this embodiment, all upper transparent strip electrodes are grounded as common electrodes, and voltages are applied to the lower transparent strip electrodes and the central transparent strip electrode, but the voltage values ​​applied to the central transparent strip electrodes and the transparent strip electrodes on both sides are different.

[0027] Attached Figure 1 The schematic diagram of a novel large-aperture liquid crystal column lens array structure of the present application before and after power is applied is shown. The structure includes an upper glass substrate, an upper transparent strip electrode, an upper orientation layer, a liquid crystal layer, a lower orientation layer, a central transparent strip electrode, a dielectric layer, a lower transparent strip electrode and a lower glass substrate. When no voltage is applied to the liquid crystal lens array, due to the effect of the orientation layer, the liquid crystal molecules are arranged in a direction perpendicular to the long side of the lower transparent strip electrode, and the refractive index in the liquid crystal layer is uniformly distributed, so there is no convergence effect on light. When a voltage is applied to the lower transparent strip electrode and the central transparent strip electrode, a spatially non-uniform electric field is formed between the upper and lower transparent strip electrodes, thereby changing the refractive index distribution inside the liquid crystal layer.

[0028] Attached Figure 2 The schematic diagram of the distribution of liquid crystal molecules under the application of a certain voltage in the embodiment of the present application is shown. The figure clearly shows that when different voltages are applied to the lower transparent strip electrodes in the center and on both sides, the liquid crystal molecules begin to deflect under the action of the electric field. This deflection phenomenon originates from the electro-optical properties of the liquid crystal material, that is, under the influence of the electric field, the orientation of the liquid crystal molecules will change, thereby causing a change in the refractive index. As the voltage gradually increases, the liquid crystal molecules are gradually arranged into an ideal gradient refractive index distribution. In addition, since a transparent strip electrode is placed in the center of the liquid crystal lens, it is used to accurately control the central electric field part while facilitating the deflection of the central liquid crystal molecules, reducing the required voltage and achieving an energy-saving effect.

[0029] Attached Figure 3The actual refractive index curve of the embodiment of the present application under voltage is shown in a schematic diagram of fitting with an ideal nonlinear curve. It can be clearly observed from the figure that the spatial distribution of the refractive index shows good symmetry relative to the center line of the lens. The fitting results show that the maximum effective refractive index is 1.7234 and the minimum effective refractive index is 1.5282, which means that the effective refractive index difference between the edge and the center of the liquid crystal column lens reaches 0.1952, reflecting a large refractive index difference, indicating that the structure can achieve the best focusing effect when a certain voltage is applied, and the minimum focal length is about 1.601mm. This result verifies the rationality of the design and shows that by precisely controlling the voltage, the arrangement of liquid crystal molecules can be optimized, thereby improving the focusing ability of the lens. In addition, this distribution characteristic of the refractive index also shows that the liquid crystal lens array can basically eliminate spherical aberration in application, further proving that the lens can maintain high image quality and reduce distortion.

[0030] The above is only a preferred embodiment of the present application, but the present application is not limited to this embodiment. It should be understood by those skilled in the art that various changes in form and details made without departing from the spirit and scope of the present application defined by the claims should all fall within the scope of the present application.

Claims

1. A novel large-aperture liquid crystal column lens array, characterized in that: include: upper glass substrate; An upper transparent strip electrode, disposed below the upper glass substrate, and used to serve as a common electrode for grounding; An upper alignment layer, disposed on the same layer as the upper transparent strip electrode, for providing a consistent initialization state for the liquid crystal molecules in the liquid crystal layer; a liquid crystal layer, disposed below the upper alignment layer; A lower alignment layer, disposed below the liquid crystal layer, for providing a consistent initialization state for liquid crystal molecules in the liquid crystal layer; A central transparent strip electrode is disposed on the same layer as the lower alignment layer and is used to provide an electric field to adjust the arrangement of the central liquid crystal molecules; A dielectric layer is provided below the central transparent strip electrode to separate the upper and lower strip electrodes, reduce the mutual interference of electric fields between the electrodes, and enhance the stability of the device; A lower transparent strip electrode is arranged on the same layer as the dielectric layer, and is used to apply voltage, provide an electric field, and adjust the arrangement of liquid crystal molecules; a lower glass substrate; The liquid crystal layer adopts a liquid crystal material with a positive dielectric constant, and the liquid crystal layer is vertically oriented relative to the long side of the transparent strip electrode.

2. The novel large-aperture liquid crystal column lens array according to claim 1, characterized in that: Dividing the common electrode into two parts can generate a non-uniform electric field, providing more precise control and thus improving the alignment of liquid crystal molecules.

3. The novel large-aperture liquid crystal cylindrical lens array according to claim 1, characterized in that: Adding a central transparent strip electrode can further accurately control the local (central) electric field distribution and improve the arrangement of liquid crystal molecules in the central part.

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