Liquid crystal lens and method for preparing the same

Abstract

The present invention provides a liquid crystal lens and a preparation method thereof. The liquid crystal lens has a simple structure, and the surfaces of each layer are flat, so it is easy to orient the liquid crystal molecules and easy to process and produce. By dividing a plurality of first electrodes in a first electrode layer into a plurality of groups, and dividing a plurality of first electrodes in a second electrode layer into a plurality of groups, and setting each group of first electrodes to have a preset electrode sampling rate, the electrode sampling rate of the group close to the optical axis is greater than the electrode sampling rate of the group far from the optical axis, so that the size of the liquid crystal lens can be made larger. By respectively setting a first electrode layer and a first common electrode layer in the first half area and the second half area of ​​the first substrate, and respectively setting a second common electrode layer and a second electrode layer in the third half area and the fourth half area of ​​the second substrate, the optical path difference distribution of the liquid crystal lens can be effectively improved, and the problem of eccentricity of the liquid crystal lens can be corrected.

Description

Technical Field

[0001] The present invention generally relates to the field of lens technology, and in particular to a liquid crystal lens and a preparation method thereof. Background Art

[0002] Liquid crystal lens mainly uses electrodes set on two substrates on both sides of the liquid crystal layer (one substrate is a common electrode, and the other substrate is a driving electrode), and applies driving voltages of different sizes to different electrodes, so as to form a vertical electric field with different strengths between the two substrates to drive the liquid crystal molecules to arrange and form a variable focus liquid crystal lens. Therefore, only the voltage distribution on the corresponding electrodes needs to be controlled, and the refractive index distribution of the liquid crystal lens will change accordingly, thereby controlling the distribution of the outgoing light passing through the liquid crystal lens. By controlling the voltage distribution on the corresponding electrodes, a non-uniform gradient distribution of the refractive index is formed in the liquid crystal layer of the liquid crystal lens, and the function of the Fresnel liquid crystal lens can be realized.

[0003] Fig. 9 FIG. 1 shows an optical path difference distribution curve of an existing equal-height Fresnel liquid crystal lens. The Fresnel liquid crystal lens is generally divided into multiple zones from the center to the edge, and the width of each zone gradually decreases from the center to the edge (i.e. Fig. 9 In the figure: W1'>W2'>W3'>…>Wi'), but each zone has the same number of driving electrodes, so the width of the driving electrodes is getting smaller and smaller. For a Fresnel lens, a ring-shaped sawtooth surface (or a central convex surface) is a zone (or a petal of a Fresnel liquid crystal lens is a zone); for a Fresnel liquid crystal lens, a voltage repetition unit can be considered as a zone, that is, there are as many zones as there are voltage repetition units. When the size of a Fresnel liquid crystal lens is large, the line width (width) of the driving electrode at the edge of the lens will be reduced to an unacceptable level. For example, if the line width is too small, it may not be processed, or if the line width is too small, the transition of the electric field cannot effectively control the liquid crystal molecules, etc., thereby limiting the further expansion of the size of the liquid crystal lens and also limiting the application of the liquid crystal lens.

[0004] In order to further expand the size of the liquid crystal lens, an electro-active lens is provided in the prior art, which includes a substrate with a stepped surface, and the stepped surface defines concentric liquid crystal regions whose thickness increases with the radius of the lens. Each region is switched by a different set of ring electrodes, which can be on the stepped surface, below the stepped surface, or opposite to the stepped surface. In each region, the farther the ring electrode is from the center of the lens, the narrower it becomes, but the width of the ring electrode also increases with the thickness of the liquid crystal, thereby offsetting the reduction in width that reduces the performance of the lens. Although the size of this electro-active lens can be made larger, the step difference around the step makes it difficult to orient the nearby liquid crystal molecules, the optical path difference distribution curve changes suddenly at the step position, and multiple liquid crystal devices of different thicknesses are difficult to process.

[0005] At present, the driving electrode in the liquid crystal lens is set on one side of the liquid crystal layer, and the common electrode is set on the other side of the liquid crystal layer. Due to the limitation of the single rubbing direction of the substrate, the optical path difference distribution curve formed by the liquid crystal lens is asymmetric relative to the geometric center of the lens, and the liquid crystal lens has an eccentricity problem. Fig.10 The optical path difference distribution curve (parallel to the rubbing orientation direction) of a liquid crystal lens with an annular electrode in the prior art is shown in FIG. 2 / 2f, where φ is the optical path difference of the liquid crystal lens, r is the lens radius, and f is the focal length of the lens). Compared with the standard curve, the optical path difference of this lens cannot be symmetrical about the geometric axis. This is mainly caused by the direction of the friction orientation, and the larger the pretilt angle, the more obvious this phenomenon is.

[0006] Cell gap and pretilt angle are two important parameters that affect the performance of liquid crystal display panels. (1) Cell gap refers to the thickness of the liquid crystal layer disposed between the upper and lower substrates. Cell gap affects the transmittance of the liquid crystal display panel and the response time of the liquid crystal. In order to obtain a display effect with high contrast, high brightness and high response speed, the cell gap must be strictly controlled. At the same time, the cell gap must be uniform to avoid the change of the background color of the liquid crystal display and cause color unevenness. (2) In order to make the liquid crystal molecules arrange more regularly, a polyimide (PI) guiding film that has been rubbed is arranged on the side of the upper and lower substrates close to the liquid crystal layer. The force between the branched groups in the PI guiding film and the liquid crystal molecules is relatively strong, which has an anchoring effect on the liquid crystal molecules, so that the liquid crystal molecules are oriented at a certain polar angle relative to the surface of the PI guiding film. This polar angle is the pretilt angle of the liquid crystal layer. The pretilt angle can control the orientation of the liquid crystal molecules and prevent the appearance of anti-tilt domains in the liquid crystal layer. It can also affect the transmittance-voltage curve of the liquid crystal layer to a certain extent. An appropriate pretilt angle can reduce the threshold voltage and speed up the response speed of the liquid crystal.

[0007] The contents of the background technology section are merely the technologies known to the inventors and do not necessarily represent the prior art in the field. Summary of the invention

[0008] In view of one or more defects in the prior art, the present invention provides a liquid crystal lens having an optical axis, the liquid crystal lens comprising:

[0009] A first substrate having a first half area and a second half area, wherein the first half area and the second half area are respectively arranged on both sides of the optical axis;

[0010] a second substrate having a third half area and a fourth half area, wherein the third half area and the fourth half area are respectively arranged on both sides of the optical axis, and the third half area is opposite to the first half area, and the fourth half area is opposite to the second half area;

[0011] a liquid crystal layer, disposed between the first substrate and the second substrate;

[0012] A first electrode layer, disposed between the first half region and the liquid crystal layer;

[0013] A first common electrode layer is disposed between the second half region and the liquid crystal layer;

[0014] a second electrode layer, disposed between the fourth half region and the liquid crystal layer, wherein the second electrode layer has the same structure as the first electrode layer;

[0015] A second common electrode layer is disposed between the third half region and the liquid crystal layer, wherein the second common electrode layer has the same structure as the first common electrode layer;

[0016] Among them, the first electrode layer and the second electrode layer respectively include a plurality of first electrodes, the plurality of first electrodes in the first electrode layer are spaced apart from the optical axis to the edge of the liquid crystal lens and divided into a plurality of groups, the plurality of first electrodes in the second electrode layer are spaced apart from the optical axis to the edge of the liquid crystal lens and divided into a plurality of groups, each group of first electrodes has a preset electrode sampling rate, and the electrode sampling rate of the group close to the optical axis is greater than the electrode sampling rate of the group far from the optical axis.

[0017] According to one aspect of the present invention, the plurality of first electrodes in the first electrode layer are divided into a plurality of regions, the plurality of first electrodes in the second electrode layer are divided into a plurality of regions, and the regions have a preset width;

[0018] Each of the groups comprises at least one region, and different groups may comprise the same or different numbers of regions;

[0019] In the same group: the electrode sampling rate of each area is the same.

[0020] According to one aspect of the present invention, the width of the zone is

[0021] Wherein, i is the ranking number of the corresponding area in the first electrode layer or the second electrode layer, and the ranking number is counted from the area closest to the optical axis in the first electrode layer or the second electrode layer toward the edge of the liquid crystal lens and starts from 1; W1 is the width of the area closest to the optical axis in the first electrode layer or the second electrode layer.

[0022] According to one aspect of the present invention, a third electrode layer is provided between the first electrode layer and the liquid crystal layer, and a first dielectric layer is provided between the first electrode layer and the third electrode layer; a fourth electrode layer is provided between the second electrode layer and the liquid crystal layer, and a second dielectric layer is provided between the second electrode layer and the fourth electrode layer; wherein the third electrode layer and the fourth electrode layer have the same structure;

[0023] Among the multiple groups of the first electrode layer: the group closest to the optical axis is the central group, and the other groups are expanded groups; among the multiple groups of the second electrode layer: the group closest to the optical axis is the central group, and the other groups are expanded groups;

[0024] The third electrode layer and the fourth electrode layer respectively include a plurality of second electrodes, the second electrodes are distributed between at least part of the groups and the liquid crystal layer, the second electrodes between the liquid crystal layer and a group and the first electrodes in the group are alternately arranged in the first direction, the second electrodes partially overlap with the first electrodes adjacent to them, and the first direction is perpendicular to the optical axis;

[0025] The first electrode is configured to output a driving voltage, and the second electrode is configured to output a coupling voltage through capacitive coupling of two first electrodes partially overlapping with the second electrode.

[0026] According to one aspect of the present invention, the plurality of second electrodes are distributed between each of the enlarged groups and the liquid crystal layer.

[0027] According to one aspect of the present invention, the plurality of second electrodes are distributed between each of the groups and the liquid crystal layer.

[0028] According to one aspect of the present invention, in the central group:

[0029] The overlapping width of each first electrode and the corresponding second electrode is the same; or,

[0030] The overlapping widths of each first electrode and the corresponding second electrode are different, and the overlapping widths of the first electrode close to the optical axis and the corresponding second electrode are greater than the overlapping widths of the first electrode far from the optical axis and the corresponding second electrode; or,

[0031] The overlapping area ratio of each second electrode and the corresponding first electrode is the same.

[0032] According to one aspect of the present invention, the plurality of second electrodes are distributed between each of the enlarged groups and the liquid crystal layer, and the second electrodes and the first electrodes in the enlarged groups have a first spacing in the optical axis direction;

[0033] The first electrodes in the central group are arranged into two layers, and the first electrodes in the two layers are alternately arranged in a first direction, and the projections of the first electrodes of the two layers in the first direction are tangent; a dielectric layer is arranged between the first electrodes of the two layers; the first electrodes in the two layers have a second spacing in the optical axis direction, and the second spacing is greater than the first spacing.

[0034] According to one aspect of the present invention, multiple first electrodes in the first electrode layer are arranged at equal intervals from the edge of the optical axis to the first half zone, and multiple first electrodes in the second electrode layer are arranged at equal intervals from the edge of the optical axis to the fourth half zone.

[0035] According to one aspect of the present invention, the liquid crystal lens further comprises a circuit bus, the circuit bus comprises a plurality of circuit branches, the plurality of circuit branches respectively provide different voltages, and the number of the circuit branches is the same as the number of the first electrodes included in one area of ​​the central group;

[0036] In the central group: the plurality of first electrodes in each of the regions correspond one-to-one to and are electrically connected to the plurality of circuit branches;

[0037] In the expanded group: the first electrode is connected to a corresponding circuit branch according to a target coupling voltage of a second electrode coupled thereto.

[0038] According to one aspect of the present invention, the circuit bus further includes a very large voltage branch and / or a very small voltage branch;

[0039] In the expanded group: the first electrode is connected to a corresponding circuit branch, a maximum voltage branch or a minimum voltage branch according to a target coupling voltage of a second electrode coupled thereto.

[0040] According to one aspect of the present invention, the surface areas of the first electrodes in the same group are the same;

[0041] In the first electrode layer: the surface areas of the first electrodes in different groups are different; in the second electrode layer: the surface areas of the first electrodes in different groups are different;

[0042] The surface area of ​​the first electrodes in the group close to the optical axis is smaller than the surface area of ​​the first electrodes in the group far from the optical axis.

[0043] According to one aspect of the present invention, in the same group: the line width of the first electrode close to the optical axis is greater than the line width of the first electrode far from the optical axis;

[0044] In two adjacent groups: the line width of the first electrode closest to the optical axis in the group far from the optical axis is greater than the line width of the first electrode farthest from the optical axis in the group close to the optical axis.

[0045] According to one aspect of the present invention, a first liquid crystal alignment layer is disposed on a side of the liquid crystal layer close to the first substrate, and the first liquid crystal alignment layer is rubbed and aligned along a side where the first common electrode layer is located toward a side where the first electrode layer is located;

[0046] A second liquid crystal alignment layer is disposed on a side of the liquid crystal layer close to the second substrate, and the second liquid crystal alignment layer is rubbed and aligned along a side where the second common electrode layer is located toward a side where the second electrode layer is located.

[0047] The present invention also provides a method for preparing a liquid crystal lens, comprising:

[0048] forming a first electrode layer on the first half area of ​​the first substrate, and forming a first common electrode layer on the second half area of ​​the first substrate;

[0049] forming a second common electrode layer on the third half region of the second substrate, and forming a second electrode layer on the fourth half region of the second substrate;

[0050] Arranging spacers on the first substrate or the second substrate;

[0051] forming a liquid crystal layer on one of the first substrate or the second substrate;

[0052] forming a plastic frame on the other of the first substrate and the second substrate; and

[0053] Assemble the first substrate and the second substrate so that the first half of the first substrate faces the third half of the second substrate, and the second half of the first substrate faces the fourth half of the second substrate, and cure the glue frame;

[0054] Among them, the first common electrode layer and the second common electrode layer have the same structure, and the first electrode layer and the second electrode layer have the same structure; the first electrode layer and the second electrode layer respectively include a plurality of first electrodes, the plurality of first electrodes in the first electrode layer are spaced apart from the optical axis to the edge of the liquid crystal lens and divided into a plurality of groups, the plurality of first electrodes in the second electrode layer are spaced apart from the optical axis to the edge of the liquid crystal lens and divided into a plurality of groups, each group of first electrodes has a preset electrode sampling rate, and the electrode sampling rate of the group close to the optical axis is greater than the electrode sampling rate of the group far from the optical axis.

[0055] According to one aspect of the present invention, the preparation method further comprises:

[0056] forming a first dielectric layer and a third electrode layer on the first electrode layer; and

[0057] forming a second dielectric layer and a fourth electrode layer on the second electrode layer;

[0058] Among the multiple groups of the first electrode layer: the group closest to the optical axis is the central group, and the other groups are expanded groups; among the multiple groups of the second electrode layer: the group closest to the optical axis is the central group, and the other groups are expanded groups;

[0059] The third electrode layer and the fourth electrode layer have the same structure, the third electrode layer and the fourth electrode layer respectively include a plurality of second electrodes, the second electrodes are distributed between at least part of the groups and the liquid crystal layer, the second electrodes between the liquid crystal layer and a group and the first electrodes in the group are alternately arranged in the first direction, the second electrodes partially overlap with the first electrodes adjacent to them, and the first direction is perpendicular to the optical axis;

[0060] The first electrode is configured to output a driving voltage, and the second electrode is configured to output a coupling voltage through capacitive coupling of two first electrodes partially overlapping with the second electrode.

[0061] According to one aspect of the present invention, the plurality of second electrodes are distributed between each of the enlarged electrode resistors and the liquid crystal layer.

[0062] According to one aspect of the present invention, the plurality of second electrodes are distributed between each of the groups and the liquid crystal layer.

[0063] According to one aspect of the present invention, the plurality of second electrodes are distributed between each of the enlarged groups and the liquid crystal layer, and the second electrodes and the first electrodes in the enlarged groups have a first spacing in the optical axis direction;

[0064] The first electrodes in the central group are arranged into two layers, and the first electrodes in the two layers are alternately arranged in a first direction, and the projections of the first electrodes of the two layers in the first direction are tangent; the first electrodes in the two layers have a second spacing in the optical axis direction, and the second spacing is greater than the first spacing.

[0065] According to one aspect of the present invention, the preparation method further comprises:

[0066] forming a first liquid crystal alignment layer on the first substrate, and rubbing and aligning the liquid crystal along the side where the first common electrode layer is located toward the side where the first electrode layer is located; and

[0067] A second liquid crystal alignment layer is formed on the second substrate, and rubbed and aligned along the side where the second common electrode layer is located toward the side where the second electrode layer is located.

[0068] Compared with the prior art, the embodiments of the present invention provide a liquid crystal lens and a method for preparing the same. The liquid crystal lens has a simple structure, and the surfaces of each layer are flat, so it is easy to orient the liquid crystal molecules and to process and produce.

[0069] By dividing the multiple first electrodes in the first electrode layer into multiple groups, dividing the multiple first electrodes in the second electrode layer into multiple groups, and setting each group of first electrodes to have a preset electrode sampling rate, the electrode sampling rate of the group close to the optical axis is greater than the electrode sampling rate of the group far from the optical axis, so that the size of the liquid crystal lens can be made larger.

[0070] By respectively arranging a first electrode layer and a first common electrode layer in the first half area and the second half area of ​​the first substrate, and respectively arranging a second common electrode layer and a second electrode layer in the third half area and the fourth half area of ​​the second substrate, the optical path difference distribution of the liquid crystal lens can be effectively improved and the problem of eccentricity of the liquid crystal lens can be corrected. BRIEF DESCRIPTION OF THE DRAWINGS

[0071] The accompanying drawings are used to provide a further understanding of the present invention and constitute a part of the specification. Together with the embodiments of the present invention, they are used to explain the present invention and do not constitute a limitation of the present invention. In the accompanying drawings:

[0072] Figure 1 shows a cross-sectional view of a liquid crystal lens 100 according to an embodiment of the present invention;

[0073] Figure 2A-2C A schematic diagram of a first electrode according to an embodiment of the present invention is shown;

[0074] Figure 3 shows a cross-sectional view of a liquid crystal lens 200 according to an embodiment of the present invention;

[0075] Figure 4 A schematic diagram showing the connection between a first electrode and a circuit bus according to an embodiment of the present invention is shown;

[0076] Figure 5 Schematic diagram of a liquid crystal lens 300 according to an embodiment of the present invention is shown;

[0077] Figure 6 Schematic diagram of a liquid crystal lens 400 according to an embodiment of the present invention is shown;

[0078] Figure 7 shows an optical path difference distribution curve of the liquid crystal lens 100 and a standard curve;

[0079] Figure 8A flow chart showing a method for preparing a liquid crystal lens according to an embodiment of the present invention is shown;

[0080] Fig. 9 An optical path difference distribution curve of a conventional equal-height Fresnel liquid crystal lens is shown;

[0081] Fig.10 The optical path difference distribution curve and the standard curve of a liquid crystal lens with an annular electrode in the prior art are shown. DETAILED DESCRIPTION

[0082] In the following, only some exemplary embodiments are briefly described. As those skilled in the art will appreciate, the described embodiments may be modified in various ways without departing from the spirit or scope of the present invention. Therefore, the drawings and descriptions are considered to be exemplary and non-restrictive in nature.

[0083] In the description of the present invention, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise" and the like indicate positions or positional relationships based on the positions or positional relationships shown in the accompanying drawings, which are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as limiting the present invention. In addition, the terms "first" and "second" are only used for descriptive purposes, and cannot be understood as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Thus, the features defined as "first" and "second" may explicitly or implicitly include one or more of the features. In the description of the present invention, the meaning of "multiple" is two or more, unless otherwise clearly and specifically defined.

[0084] In the description of the present invention, it should be noted that, unless otherwise clearly specified and limited, the terms "installed", "connected", and "connected" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection, an electrical connection, or can communicate with each other; it can be directly connected, or indirectly connected through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0085] In the present invention, unless otherwise clearly specified and limited, a first feature being "above" or "below" a second feature may include that the first and second features are in direct contact, or may include that the first and second features are not in direct contact but are in contact through another feature between them. Moreover, a first feature being "above", "above" and "above" a second feature includes that the first feature is directly above and obliquely above the second feature, or simply means that the first feature is higher in level than the second feature. A first feature being "below", "below" and "below" a second feature includes that the first feature is directly above and obliquely above the second feature, or simply means that the first feature is lower in level than the second feature.

[0086] The disclosure below provides many different embodiments or examples to realize different structures of the present invention. In order to simplify the disclosure of the present invention, the parts and settings of specific examples are described below. Of course, they are only examples, and the purpose is not to limit the present invention. In addition, the present invention can repeat reference numbers and / or reference letters in different examples, and this repetition is for the purpose of simplicity and clarity, which itself does not indicate the relationship between the various embodiments and / or settings discussed. In addition, the present invention provides various specific examples of processes and materials, but those of ordinary skill in the art can be aware of the application of other processes and / or the use of other materials.

[0087] The embodiments of the present invention are described below in conjunction with the accompanying drawings. It should be understood that the embodiments described herein are only used to illustrate and explain the present invention, and are not used to limit the present invention.

[0088] Figure 1 A cross-sectional view of a liquid crystal lens 100 according to an embodiment of the present invention is shown below. Figure 1 Describe in detail.

[0089] like Figure 1As shown, the liquid crystal lens 100 has an optical axis, which may be located at the center of the liquid crystal lens 100. The liquid crystal lens 100 includes a first substrate 110, a second substrate 120, a liquid crystal layer 130, a first common electrode layer 140, a second common electrode layer 150, a first electrode layer 161, and a second electrode layer 162, wherein the first substrate 110 and the second substrate 120 are transparent substrates (for example, glass substrates), the first substrate 110 has a first half area 111 and a second half area 112, the first half area 111 and the second half area 112 are respectively located on both sides of the optical axis, the second substrate 120 has a third half area 121 and a fourth half area 122, the third half area 121 and the fourth half area 122 are respectively located on both sides of the optical axis, and the first half area 111 is opposite to the third half area 121, and the second half area 112 is opposite to the fourth half area 122. The liquid crystal layer 130 is disposed between the first substrate 110 and the second substrate 120. The first common electrode layer 140 and the second common electrode layer 150 have the same structure. The first common electrode layer 140 and the second common electrode layer 150 can be surface electrodes, wherein the first common electrode layer 140 is arranged between the second half area 112 and the liquid crystal layer 130, and the second common electrode layer 150 is arranged between the third half area 121 and the liquid crystal layer 130. The first electrode layer 161 and the second electrode layer 162 have the same structure, wherein the first electrode layer 161 is arranged between the first half area 111 and the liquid crystal layer 130, and the second electrode layer 162 is arranged between the fourth half area 122 and the liquid crystal layer 130. Specifically, the first electrode layer 161 and the second electrode layer 162 respectively include a plurality of first electrodes 163. The plurality of first electrodes 163 in the first electrode layer 161 are arranged at intervals from the optical axis to the edge of the liquid crystal lens 100 and are divided into a plurality of groups. Similarly, the plurality of first electrodes 163 in the second electrode layer 162 are also arranged at intervals from the optical axis to the edge of the liquid crystal lens 100 and are divided into a plurality of groups.

[0090] like Figure 2A , 2B As shown in , 2C, the first electrode 163 may be a semicircular ring electrode. Specifically, the first electrode 163 closest to the optical axis in the first electrode layer 161 is semicircular, and the other first electrodes 163 are semicircular rings, for example, all with the optical axis as the center. Similarly, the first electrode 163 closest to the optical axis in the second electrode layer 162 is semicircular, and the other first electrodes 163 are semicircular rings, for example, all with the optical axis as the center.

[0091] like Figure 1As shown, each group of first electrodes 163 has a preset electrode sampling rate (the electrode sampling rate refers to the number of first electrodes 163 contained in each wavelength optical path difference provided by the liquid crystal lens, and the electrode sampling rate is greater than zero). In the first electrode layer 161 and the second electrode layer 162: the electrode sampling rates of the groups with the same distance from the optical axis are the same, for example, the electrode sampling rate of the first group in the first electrode layer 161 is equal to the electrode sampling rate of the first group in the second electrode layer 162, and the electrode sampling rate of the second group in the first group is equal to the electrode sampling rate of the second group in the second electrode layer 162. In the first electrode layer 161 and the second electrode layer 162: the electrode sampling rate of the group close to the optical axis is greater than the electrode sampling rate of the group far from the optical axis. For example Figure 1 As shown, the first group has a first electrode sampling rate, the second group has a second electrode sampling rate, and the third group has a third electrode sampling rate, wherein the first electrode sampling rate>the second electrode sampling rate>the third electrode sampling rate. Figure 1 Although only three groups of the first electrode layer 161 and three groups of the second electrode layer 162 are shown in the figure, the present invention is not limited thereto, and can be set to two or more groups according to the limit of the processing technology or the actual production needs. By gradually reducing the electrode sampling rate between multiple groups, the width of the first electrode 163 can be controlled within the required range, thereby expanding the processable size range of the liquid crystal lens 100. By respectively arranging the first electrode layer 161 and the first common electrode layer 140 in the first half area 111 and the second half area 112 of the first substrate 110, and respectively arranging the second common electrode layer 150 and the second electrode layer 162 in the third half area 121 and the fourth half area 122 of the second substrate 120, the optical path difference distribution of the liquid crystal lens 100 can be effectively improved, and the problem of eccentricity of the liquid crystal lens can be corrected.

[0092] According to one embodiment of the present invention, Figure 1 As shown in FIG. 2 , the liquid crystal lens 100 may further include a first liquid crystal orientation layer 170 and a second liquid crystal orientation layer 180, both of which are disposed close to the liquid crystal layer 130, wherein the first liquid crystal orientation layer 170 is disposed on a side of the liquid crystal layer 130 close to the first substrate 110, and the first liquid crystal orientation layer 170 is rubbed and oriented along the side where the first common electrode layer 140 is located to the side where the first electrode layer 161 is located, and the second liquid crystal orientation layer 180 is disposed on a side of the liquid crystal layer 130 close to the second substrate 120, and the second liquid crystal orientation layer 180 is rubbed and oriented along the side where the second common electrode layer 150 is located to the side where the second electrode layer 162 is located. In other embodiments, the first liquid crystal orientation layer 170 may be rubbed and oriented along the side where the first electrode layer 161 is located to the side where the first common electrode layer 140 is located, and the second liquid crystal orientation layer 180 may be rubbed and oriented along the side where the second electrode layer 162 is located to the side where the second common electrode layer 150 is located.

[0093] According to one embodiment of the present invention, Figure 1 As shown, the first electrodes 163 in the first electrode layer 161 are divided into a plurality of regions, and the first electrodes 163 in the second electrode layer 162 are divided into a plurality of regions, each region including one or more first electrodes 163 and having a preset width. The width of a region can be, for example, Wherein, i is the ranking number of the corresponding area in the first electrode layer 161 or the second electrode layer 162, and the ranking number is counted from the area closest to the optical axis in the first electrode layer 161 or the second electrode layer 162 to the edge of the liquid crystal lens 100 and starts from 1; W1 is the width of the area closest to the optical axis in the first electrode layer 161 or the second electrode layer 162 (that is, the width of the area with a ranking number of 1 in the first electrode layer 161 or the second electrode layer 162), and the calculation of W1 is described in detail later. Each group contains at least one area, and different groups contain the same or different numbers of areas. In the same group, the electrode sampling rate of each area is the same. For a zone, different voltages are provided to different first electrodes 163 in the zone, so that the liquid crystal relative to the zone can be deflected at different angles to form a lens area of ​​the Fresnel liquid crystal lens.

[0094] According to one embodiment of the present invention, Figure 1 As shown, the surface areas of the first electrodes 163 in the same group are the same, the surface areas of the first electrodes 163 in different groups in the first electrode layer 161 are different, and similarly, the surface areas of the first electrodes 163 in different groups in the second electrode layer 162 are different. The surface area of ​​the first electrodes 163 in the group close to the optical axis is smaller than the surface area of ​​the first electrodes 163 in the group far from the optical axis, for example Figure 1 As shown, in the first electrode layer 161: the surface area of ​​the first electrode 163 in the first group is less than the surface area of ​​the first electrode 163 in the second group is less than the surface area of ​​the first electrode 163 in the third group. The surface area of ​​the first electrode 163 mentioned here refers to the area including the corresponding first electrode 163 and the gap within a preset range beside the first electrode 163. In the present embodiment, the surface area of ​​the first electrode 163 refers to the area including the corresponding first electrode 163 and half of the gap inside the first electrode 163 and half of the gap outside the first electrode 163; in other embodiments, the surface area of ​​the first electrode 163 refers to the area including the corresponding first electrode 163 and the gap inside (or outside) the first electrode 163.

[0095] According to one embodiment of the present invention, Figure 1As shown, the multiple first electrodes 163 in the first electrode layer 161 are arranged at equal intervals from the edge of the first half area 111 along the optical axis. The multiple first electrodes 163 in the second electrode layer 162 are arranged at equal intervals from the edge of the fourth half area 122 along the optical axis. Regarding the gap between adjacent first electrodes 163: when the gap is small, for example, less than 3μm, there is no obvious effect on the display effect of the liquid crystal lens, but if the gap is further reduced, the improvement of the display effect of the liquid crystal lens 100 is small (or no improvement), and the processing difficulty will increase; when the gap is large, it will have an adverse effect on the display effect of the liquid crystal lens 100; therefore, the size of the gap is usually selected to be a value that does not affect the effect but can be processed; arranging the first electrodes 163 at equal intervals can facilitate the design and processing of the liquid crystal lens.

[0096] According to one embodiment of the present invention, Figure 1 As shown, in the same group, the line width of the first electrode 163 close to the optical axis (i.e., the radial width of the annular electrode) is greater than the line width of the first electrode 163 far from the optical axis. Specifically, in the above preferred embodiment, since the surface areas of the first electrodes 163 in the same group are the same, in the same group: the difference between the outer diameter and the inner diameter of the first electrode 163 closer to the optical axis is greater, and the difference between the outer diameter and the inner diameter of the first electrode 163 farther from the optical axis is smaller, and accordingly, the line width of the first electrode 163 closer to the optical axis is greater, and the line width of the first electrode 163 farther from the optical axis is smaller.

[0097] like Figure 1 As shown in FIG. 1 , in two adjacent groups, the line width of the first electrode 163 closest to the optical axis in the group far from the optical axis is greater than the line width of the first electrode 163 farthest from the optical axis in the group close to the optical axis. The first electrode 163 in the liquid crystal lens 100 is processed as follows: Figure 1For example, within the first group range (1 to m-1 zone), the first electrode sampling rate is used, and the line width of the first electrode 163 gradually decreases along the first direction according to the equal area rule (the surface area of ​​the first electrodes 163 in the same group is the same), until the line width of the first electrode 163 at the edge just meets the design or processing requirements; when the size of the liquid crystal lens 100 is further increased according to this equal area rule, the line width of the first electrode 163 will not meet the design or processing requirements, so the electrode sampling rate is reduced (the second electrode sampling rate is used) within the second group range (m to n-1 zone) to increase the surface area of ​​the first electrode 163, that is, the width of the first electrode 163 is increased; when the second electrode sampling rate is used to a certain size, the line width of the first electrode 163 will not meet the design or processing requirements, so the electrode sampling rate is further reduced (the third electrode sampling rate is used) within the third group range (n to i zone) to further increase the surface area of ​​the first lens, that is, the width of the first electrode 163 is increased, and the lens size can be further expanded. Similarly, by gradually reducing the electrode sampling rate among multiple groups, the width of the first electrode 163 can be controlled within a required range, thereby expanding the processable size range of the liquid crystal lens 100 .

[0098] In the first electrode layer 161: since the electrode sampling rate of each group is different, the number of first electrodes 163 contained in the areas in different groups is different. When forming the same focal length, the voltages required to be allocated to the first electrodes 163 in different groups are different. In some embodiments, the power supply circuit can be used to provide each first electrode 163 with the required voltage; the same is true in the second electrode layer 162, which will not be repeated here. It should be noted that the first electrode 163 in the second electrode layer 162 and the first electrode 163 in the first electrode layer 161 can use the same power supply circuit.

[0099] Figure 3 FIG. 4 shows a cross-sectional view of a liquid crystal lens 200 according to an embodiment of the present invention. Figure 3As shown, the difference between the liquid crystal lens 200 and the liquid crystal lens 100 is that: a third electrode layer 191 is provided between the first electrode layer 161 and the liquid crystal layer 130, and a first dielectric layer (not shown in the figure) is provided between the first electrode layer 161 and the third electrode layer 191. A fourth electrode layer 192 is provided between the second electrode layer 162 and the liquid crystal layer 130, and a second dielectric layer (not shown in the figure) is provided between the second electrode layer 162 and the fourth electrode layer 192. For the convenience of description, among the multiple groups of the first electrode layer 161: the group closest to the optical axis is called the central group, and the other groups are called the expanded groups; among the multiple groups of the second electrode layer 162: the group closest to the optical axis is called the central group, and the other groups are called the expanded groups. The third electrode layer 191 and the fourth electrode layer 192 have the same structure. The third electrode layer 191 and the fourth electrode layer 192 respectively include a plurality of second electrodes 193. The second electrodes 193 are arranged between at least some of the groups and the liquid crystal layer 130. For example, in the liquid crystal lens 200, the plurality of second electrodes 193 are distributed between each enlarged group and the liquid crystal layer 130 (that is, the plurality of second electrodes 193 in the third electrode layer 191 are distributed between each enlarged group of the first electrode layer 161 and the liquid crystal layer 130, and the plurality of second electrodes 193 in the fourth electrode layer 192 are distributed between each enlarged group of the second electrode layer 162 and the liquid crystal layer 130). The second electrodes 193 located between the liquid crystal layer 130 and a group and the first electrodes 163 in the group are alternately arranged in the first direction. The second electrodes 193 partially overlap with the first electrodes 163 adjacent to them. The first direction is perpendicular to the optical axis. In this embodiment, the first direction is from the optical axis to the edge of the liquid crystal lens 200. The first electrode 163 is configured to output a driving voltage, and the second electrode 193 is used as a floating electrode. The second electrode 193 can output a coupling voltage through two first electrodes 163 partially overlapping with it through capacitive coupling. The magnitude of the coupling voltage is related to the driving voltage output by the two first electrodes 163 coupled with the corresponding second electrode 193, and is also related to the overlapping area of ​​the corresponding second electrode 193 with the corresponding first electrode 163. By providing the third electrode layer 191 and the fourth electrode layer 192, and using the second electrode 193 as a floating electrode, the driving of the liquid crystal lens 200 can be simplified.By providing the first electrode layer and the fourth electrode layer 192, the first electrode 163 and the second electrode 193 can cooperate with the corresponding first common electrode layer 140 or the second common electrode layer 150 to provide more voltage difference on both sides of the liquid crystal layer 130, thereby improving the display effect of the liquid crystal lens 200; wherein, at the position where the second electrode 193 is provided, the second electrode 193 and the first common electrode layer 140 or the second common electrode layer 150 provide a voltage difference for the liquid crystal layer 130; at the position where the second electrode 193 is not provided (for example: the range where the central group is located, the interval between two adjacent second electrodes 193), the first electrode 163 and the first common electrode layer 140 or the second common electrode layer 150 provide a voltage difference for the liquid crystal layer 130. The thickness of the first dielectric layer and the second dielectric layer can be as small as possible, so that the second electrode 193 is as close to the first electrode 163 as possible, thereby improving the coupling effect between the second electrode 193 and the first electrode 163.

[0100] According to one embodiment of the present invention, the liquid crystal lens 200 further includes a circuit bus, the circuit bus includes a plurality of circuit branches, the plurality of circuit branches respectively provide different voltages, and the number of circuit branches is the same as the number of first electrodes included in one zone of the central group. In the central group, the plurality of first electrodes in each zone correspond to and are electrically connected to the plurality of circuit branches one by one; in the expanded group, the first electrode is connected to the corresponding circuit branch according to the target coupling voltage of the second electrode 193 coupled thereto.

[0101] Figure 4 FIG. 1 shows a schematic diagram of the connection between the first electrode and the circuit bus according to an embodiment of the present invention. For the convenience of description and understanding, Figure 4 Only three groups of the first electrode layer 161 are shown in FIG. 1 , assuming that each group contains two regions, and the number of first electrodes contained in each region is at most 10. In fact, the number of groups, the number of regions contained in each group, and the number of first electrodes contained in each region are not limited to this, and are not limited here. Figure 4 As shown, since the electrode sampling rate of the first group (central group) is the highest, the area in the first group contains the largest number of first electrodes, and the number of circuit branches that power the first electrodes in the first group is equal to the number of voltages required to be provided to the first electrodes within the first group (that is, equal to the number of first electrodes in a single area of ​​the first group). Since the electrode sampling rate is reduced, the number of voltages required to be provided to the first electrodes within the second group (expanded group) and the third group (expanded group) are less than the number of voltages required to be provided to the first electrodes within the first group, and the maximum and minimum values ​​of the voltages required to be provided to the first electrodes within the second group and the third group are generally within the maximum and minimum voltages provided for the first electrodes within the first group.

[0102] Suppose the first electrode ( Figure 4 If the number of the first electrodes 163a-163j in the first group is 10, the number of voltages required to be provided by the first electrodes 163a-163j in the first group is 10, and the circuit bus includes 10 circuit branches, and the 10 circuit branches respectively provide voltages

[0103] V1, V2, ..., V9, V10, where V1 is the smallest, V10 is the largest, and the voltage increases monotonically (here only the voltage monotonically increases as an example, but it is not limited to this. In other embodiments, the voltages V1 to V10 may also decrease monotonically). The first electrodes 163a to 163j within the first group are respectively connected to the corresponding circuit branches. The first electrodes ( Figure 4 The number of the first electrodes 163a'~163h') in the second group is 8, and the first electrodes 163a'~163h' in the second group are respectively connected to the corresponding circuit branches, and the first electrodes 163a'~163h' in each area within the second group are respectively coupled with the corresponding second electrodes 193, so that the 7 second electrodes 193 corresponding to the corresponding area output coupling voltages V1'~V7' respectively. For example, when the required target coupling voltage V1' is between V1 and V3, the first electrode 163a' is connected to the circuit branch V1, and the first electrode 151b' is connected to the circuit branch V3, and the coupling voltage V1' is obtained by overlapping and coupling the corresponding second electrode 193 with the first electrodes 163a' and 163b' with an appropriate area, wherein V1<V1'<V3. The first electrodes ( Figure 4 The number of the first electrodes 163a"~163e") is 5, the first electrodes 163a"~163e" within the third group are respectively connected to the corresponding circuit branches, and the first electrodes 163a"~163e" of each area within the third group are respectively coupled with the corresponding second electrodes 193, so that the 4 second electrodes 193 corresponding to the corresponding area output coupling voltages V1"~V4". For example, when the coupling voltage V1" is between V3 and V4, the first electrode 163a" is connected to the circuit branch line V3, and the first electrode 163b" is connected to the circuit branch line V4, and the coupling voltage V1" is obtained by overlapping and coupling with the first electrodes 163a", 163b" with an appropriate area through the corresponding second electrode 193, wherein V3<V1"<V4; for another example, when the coupling voltage V1" is between V4 and V6, the first electrode 163b" is connected to the circuit branch line V4, and the first electrode 163c" is connected to the circuit branch line V6, and the coupling voltage V2" is obtained by overlapping and coupling with the first electrodes 163b", 163c" with an appropriate area through the corresponding second electrode 193, wherein V4<V2"<V6.

[0104] According to one embodiment of the present invention, Figure 4As shown, the circuit bus may also include a maximum voltage branch Vmax and / or a minimum voltage branch Vmi n. In the expanded group, the first electrode may be connected to the corresponding circuit branch, the maximum voltage branch Vmax or the minimum voltage branch Vmi n according to the target coupling voltage of the second electrode 193 coupled thereto; specifically, when the maximum voltage value required to be provided by the first electrode in an expanded group is greater than the maximum voltage value required to be provided by the first electrode in the central group, the corresponding first electrode in the expanded group may be connected to the maximum voltage branch Vmax; when the minimum voltage value required to be provided by the first electrode in an expanded group is smaller than the minimum voltage value required to be provided by the first electrode in the central group, the corresponding first electrode in the expanded group may be connected to the minimum voltage branch Vmi n.

[0105] Figure 5 FIG. 4 shows a cross-sectional view of a liquid crystal lens 300 according to an embodiment of the present invention. Figure 5 As shown, the difference between the liquid crystal lens 300 and the liquid crystal lens 200 is that: the plurality of second electrodes 193 are distributed between each group and the liquid crystal layer 130, that is, the plurality of second electrodes 193 in the third electrode layer 191 are distributed between each group (central group, enlarged group) of the first electrode layer 161 and the liquid crystal layer 130, and the plurality of second electrodes 193 in the fourth electrode layer 192 are distributed between each group (central group, enlarged group) of the second electrode layer 162 and the liquid crystal layer 130. By arranging the second electrodes 193 in the range corresponding to the central group, more voltage difference can be provided on both sides of the liquid crystal layer 130, further improving the display effect of the liquid crystal lens.

[0106] According to one embodiment of the present invention, Figure 5As shown, in the central group, each first electrode 163 has the same overlapping width with the corresponding second electrode 193, for example, the overlapping width of the first electrode 163 and the corresponding second electrode 193 may be 5 μm (in other embodiments, it may also be 3 μm, 6 μm, etc., and the present invention is not limited thereto); or, each first electrode 163 has the same overlapping area ratio with the corresponding second electrode 193, for example, the overlapping area ratio of the first electrode 163 and the corresponding second electrode 193 may be 25% (in other embodiments, it may also be 20%, 30%, etc., and the present invention is not limited thereto, and the overlapping area ratio is the overlapping area / the area of ​​the first electrode), or, each first electrode 163 has different overlapping widths with the corresponding second electrode 193, and the overlapping width of the first electrode 163 close to the optical axis and the corresponding second electrode 193 is greater than the overlapping width of the first electrode 163 and the corresponding second electrode 193 far from the optical axis, that is, the overlapping width of the first electrode 163 and the second electrode 193 gradually decreases from the optical axis to the edge of the liquid crystal lens 300. Among them, when the second electrode 193 is set according to the same overlapping width, it is necessary to take that all the second electrodes 193 do not short-circuit as the limit / maximum value of the line width (that is, the second electrode 193 cannot be wider, otherwise a short circuit will occur). Therefore, the overlapping width of the second electrode 193 and the first electrode 163 may only occupy a very small part of the corresponding first electrode 163 (for example, the first electrode 163 closest to the optical axis), and the coupling effect between the second electrode 193 and the first electrode 163 is limited; however, when the second electrode 193 is set according to the same overlapping area ratio, this problem does not exist, because when the overlapping area ratio is the same, the line width of the second electrode 193 may be different (the larger the overlapping area of ​​the second electrode 193 and the first electrode 163, the larger the line width of the corresponding second electrode 193), and the second electrode 193 and the first electrode 163 can have a good coupling effect. Therefore, setting the second electrode 193 according to the same overlapping area ratio has a better effect; similarly, setting the second electrode 193 according to the rule that the overlapping width gradually decreases from the optical axis to the edge of the liquid crystal lens also has a better effect. Within the range corresponding to the central group, the line width of the second electrode 193 is determined according to the overlapping width or overlapping area ratio with the corresponding first electrode 163, which can make the processing of the second electrode layer 162 more convenient. Within the range corresponding to the expanded group, the line width of the second electrode 193 is determined according to the coupling voltage required to be output.

[0107] Figure 6 FIG. 4 shows a cross-sectional view of a liquid crystal lens 400 according to an embodiment of the present invention. Figure 6As shown, the difference between the liquid crystal lens 400 and the liquid crystal lens 200 is that the first electrodes 163 in the central group are arranged in two layers, and the first electrodes 163 in the two layers are alternately arranged in the first direction. Preferably, the projections of two adjacent first electrodes 163 in the central group in the first direction on the first plane (the first plane is perpendicular to the optical axis) are tangent and do not overlap, and preferably form a tangent, that is, there is no gap between the two. In the liquid crystal lens 400, the two layers of first electrodes 163 in the first electrode layer 161 and the second electrodes 193 in the third electrode layer 191 are arranged in different layers, and the layers are separated and insulated by the first dielectric layer; preferably, as Figure 6 As shown, the layer where the second electrode 193 is located (the third electrode layer 191 or the fourth electrode layer 192) is located between the two layers of the first electrode 163 (the second electrode 193 and the first electrode 163 in the corresponding enlarged group have a first spacing in the optical axis direction, and the two layers of the first electrode 163 have a second spacing, which is greater than the first spacing), so that the second electrode 193 is as close as possible to the first electrode 163 coupled thereto. By dividing the first electrode 163 in the central group into two layers, the problem of weak process capability can be well solved. In the case of relatively weak process capability, the gap between adjacent electrodes will be relatively large, thereby affecting the display effect of the liquid crystal lens; if the electrodes are distributed in the same layer with a smaller gap, the risk of short circuit between adjacent electrodes will increase. Dividing the first electrode 163 into two layers can increase the gap between the first electrodes in the same layer, thereby making it less likely for the first electrodes in the same layer to short circuit; at the same time, the upper and lower layers of the first electrodes are separated by a dielectric layer, so they are not easily short-circuited; the electric field is continuously transitioned in the first direction, which can well solve the problem of weak process capability. To intuitively demonstrate the effects of the embodiments of the present invention, examples are given below.

[0108] The basic principle of the Fresnel liquid crystal lens is that, under the action of an external electric field, a non-uniform gradient distribution of refractive index is formed in the liquid crystal layer 130. The focal length f of the Fresnel liquid crystal lens is: Where: r is the radius of the Fresnel liquid crystal lens; Δn is the birefringence coefficient of the liquid crystal material; d is the thickness of the liquid crystal layer 130, and q is the number of Fresnel lens partitions. The optical path difference distribution curve of the Fresnel liquid crystal lens φ = r 2 / (2f*q)=Δn*d, where φ is the optical path difference of the liquid crystal lens. Assuming that the optical path difference provided by the box thickness of the Fresnel liquid crystal lens is pλ (p is the wave number), then pλ=φ=Δn*d.

[0109] [Regarding the calculation of the electrode sampling rate: (1) For a certain liquid crystal lens product, the product of Δn and d (Δn*d) that can be measured by the instrument, λ is known, so p can be calculated according to the above formula; (2) For a certain liquid crystal lens product, the number N of first electrodes (driving electrodes) contained in a certain area can be measured by the equipment, so the electrode sampling rate fs=N / p in the area can be calculated. It should be noted that the electrode sampling rate obtained by this calculation method is obtained by reverse engineering and is not used to limit the electrode sampling rate in this application; the electrode sampling rate in this application is set according to engineering processing limits or actual needs. ]

[0110] The line width calculation process of the first electrode 163 in the liquid crystal lenses 100, 200, 300, and 400 is as follows (taking the first electrode 163 in the first electrode layer 161 as an example):

[0111] (1) Radius of the central first electrode (the first electrode 163 closest to the optical axis) Where λ is the wavelength of incident light, f is the focal length, and fs1 is the electrode sampling rate of the first group.

[0112] The radius of the x-th first electrode 163 (x is the serial number of the first electrode 163 and is sorted from the optical axis to the edge of the liquid crystal lens) in the first group Thus, the width of each first electrode 163 can be calculated.

[0113] The number of first electrodes 163 in each zone in the first group is determined by the electrode sampling rate and the cell thickness of the liquid crystal lens (assuming that the cell thickness of the liquid crystal lens can provide an optical path difference of pλ, where p is the wave number). In the first group: the number of first electrodes 163 in each zone is n1=p*fs1;

[0114] The width of the first area (the area with sort number 1) The radius of the first zone R1=W1, the area of ​​the first zone S1=πW12 / 2;

[0115] The width of the second area (the area with sort number 2) The outer radius of the second zone The area of ​​the second zone S2 = πW12 / 2;

[0116] …

[0117] The width of the i-th area (the area with sorting number i) The outer circle radius of the i-th zone Ri=W1+W2+…+Wi, and the area of ​​the i-th zone Si=πW12 / 2.

[0118] The area of ​​each district is equal.

[0119] The electrode sampling rate of the first group is determined, the number of zones contained in the first group is determined by the fact that all electrodes in the zone must meet the processing limit of the minimum width, and the spacing between each first electrode 163 in each group is equal.

[0120] (2) Assume that the first group contains regions 1 to m-1, and the area of ​​the first group is (m-1)πW12 / 2. Then the second group starts from region m, and the width of region m is The surface area of ​​the first m regions in the second group is Sm=πW12 / 2.

[0121] (3) Determine the electrode sampling rate fs2 of the second group. The number of first electrodes 163 in each zone of the second group is n2=p*fs2.

[0122] (4) Since the surface area of ​​each first electrode 163 in the same group is the same, the surface area of ​​the first first electrode 163 in the second group (the first electrode 163 in the second group closest to the optical axis) = Sm / (2*n2) = πW12 / (2*n2);

[0123] Assuming that the radius of the outer ring of the first first electrode 163 in the second group is r1', the area enclosed by the outer circle of the first first electrode 163 in the second group = ((m-1)πW12+Sm / n2) / 2 = ((m-1+1 / n2)πW12) / 2 = π*r1'2 / 2, and then r1' can be calculated; the circular area of ​​the second first electrode 163 in the second group = ((m-1)πW12+2Sm / n2) / 2 = π*r2'2 / 2, and then r2' can be calculated, and so on, the radius of each first electrode 163 in the first m-region of the second group can be calculated. The method for calculating the radius of the first first electrode 163 in the region after the m-region of the second group is the same as the method for calculating the radius of the ring of the first first electrode 163 in the m-region of the second group, which will not be repeated here.

[0124] (5) The electrode sampling rate of the second group is determined. The number of zones contained in the second group is determined by the fact that all electrodes in the zone must meet the minimum width processing limit, and the spacing between each first electrode 163 in each group is equal.

[0125] (6) The calculation method of the ring radius of the first first electrode 163 in other groups (the third group, the fourth group, etc.) is the same as the calculation method of the ring radius of the first first electrode 163 in the second group, which will not be described in detail here.

[0126] like Figure 1As shown, assuming that the cell thickness of the liquid crystal lens can provide an optical path difference of 10λ (λ=543.5nm), the focal length f of the liquid crystal lens is 1000mm, and the electrode sampling rate of the first group (first electrode sampling rate) fs1 is 5, then the number of electrodes n1 contained in each zone in the first group is 10*5=50. The radius of the central first electrode (the first electrode 163 closest to the optical axis) The width of the first zone (the zone with a ranking number of 1, the ranking number is counted from the zone closest to the optical axis to the edge of the liquid crystal lens and starts from 1) Assuming that the width of the gap between adjacent first electrodes 163 is 4 μm, the minimum width of the first electrode 163 that can be realized is 10 μm. As shown in Table 1, when the number of first electrodes 163 is 277, the line width of the first electrode 163 reaches the limit value of 10 μm, and the maximum radius of the liquid crystal lens is about 7.7 mm. Obviously, when the electrode sampling rate is 5, the line width of some first electrodes 163 in the sixth zone (the zone with a sorting number of 6) will not be realized, so the first zone to the fifth zone (the zone with a sorting number of 1 to 5) can be regarded as the first group, and the sixth zone can be classified as the second group. The electrode sampling rate of the second group (the second electrode sampling rate) can be reduced to 4 (the electrode sampling rate can also be set to a decimal according to actual needs, such as 4.5), then the number of electrodes n2 contained in each zone in the second group is 10*4=40, and the 40 first electrodes 163 are divided according to the equal area rule, and the line width of all first electrodes 163 in the sixth zone can be adjusted to more than 10. When the first electrode sampling rate is adopted, the line width of part of the first electrode 163 in the sixth area will not meet the design or processing requirements, while when the sixth area is divided into the second group and the second sampling rate is adopted, the line width of the first electrode 163 in the sixth area will meet the requirements and increase the size of the liquid crystal lens to about 8.1 mm. Similarly, the size of the liquid crystal lens can be further increased by further reducing the electrode sampling rate.

[0127]

[0128]

[0129] Table 1

[0130] Figure 7 The optical path difference distribution curve and the standard curve of one of the liquid crystal lenses 100 / 200 / 300 / 400 in the above embodiments, such as the liquid crystal lens 100 (assuming that the thickness of the liquid crystal layer 130 is 65 μm and the liquid crystal material Δn=0.3) are shown. Figure 7 In order to compare the symmetry of the optical path difference, only the optical path difference (λ=543.5nm) of the center of the lens, i.e. the two first zones, is extracted to compare with the standard curve. Figure 7 As shown, the optical path difference distribution curve of the liquid crystal lens 100 has good symmetry relative to the geometric center. Fig.10The optical path difference distribution of a certain liquid crystal lens shown is significantly improved, and the problem of eccentricity of the liquid crystal lens can be corrected.

[0131] Compared with the prior art, the liquid crystal lenses 100, 200, 300, and 400 provided in the embodiments of the present invention have a simple structure, and the surfaces of each layer are flat, so that the liquid crystal molecules can be easily oriented, and the processing and production can be easy. The size can be larger, and the optical path difference distribution of the liquid crystal lens can be effectively improved, and the eccentricity problem of the liquid crystal lens can be corrected.

[0132] Figure 8 A method for preparing a liquid crystal lens according to an embodiment of the present invention is shown below. Figure 8 Describe in detail.

[0133] The method for preparing the liquid crystal lens includes the following steps, which are described in detail below.

[0134] In step S410 , a first electrode layer is formed on a first half region of the first substrate, and a first common electrode layer is formed on a second half region of the first substrate.

[0135] In step S420 , a second electrode layer is formed on the third half region of the second substrate, and a second common electrode layer is formed on the fourth half region of the second substrate.

[0136] The first common electrode layer has the same structure as the second common electrode layer. The formation of the first common electrode layer includes arranging a surface electrode in the second half region, and the formation of the second common electrode layer includes arranging a surface electrode in the third half region. The first electrode layer has the same structure as the second electrode layer. The first electrode layer and the second electrode layer respectively include a plurality of first electrodes. The plurality of first electrodes in the first electrode layer are arranged at intervals from the edge of the optical axis to the liquid crystal lens and divided into a plurality of groups. Similarly, the plurality of first electrodes in the second electrode layer are also arranged at intervals from the edge of the liquid crystal lens to the optical axis and divided into a plurality of groups. Each group of first electrodes has a preset electrode sampling rate (the electrode sampling rate refers to the number of first electrodes contained in each wavelength optical path difference, and the electrode sampling rate is greater than zero). In the first electrode layer and the second electrode layer: the electrode sampling rates of the groups with the same distance from the optical axis are the same, for example, the electrode sampling rate of the first group in the first electrode layer is equal to the electrode sampling rate of the first group in the second electrode layer, and the electrode sampling rate of the second group in the first group is equal to the electrode sampling rate of the second group in the second electrode layer. In the first electrode layer and the second electrode layer: the electrode sampling rate of the group close to the optical axis is greater than the electrode sampling rate of the group far from the optical axis. The first electrode may be a semicircular ring electrode. Specifically, the first electrode in the first electrode layer closest to the optical axis is semicircular, and the other first electrodes are in semicircular ring shapes, for example, all with the optical axis as the center; similarly, the first electrode in the second electrode layer closest to the optical axis is semicircular, and the other first electrodes are in semicircular ring shapes, for example, all with the optical axis as the center.

[0137] Step S430: spacers are arranged on the first substrate or the second substrate, for example, the spacers may be arranged on a side of the first substrate where the first electrode layer and the first common electrode layer are provided.

[0138] Step S440: forming a liquid crystal layer on one of the first substrate and the second substrate, for example, the liquid crystal layer can be formed on a side of the first substrate where the first electrode layer and the first common electrode layer are provided.

[0139] Step S450: forming a plastic frame on the other of the first substrate and the second substrate, for example, the plastic frame can be formed on the side of the second substrate where the second electrode layer and the second common electrode layer are provided.

[0140] In step S460 , the first substrate and the second substrate are combined so that the first half area of ​​the first substrate is opposite to the third half area of ​​the second substrate, and the second half area of ​​the first substrate is opposite to the fourth half area of ​​the second substrate, and the glue frame is cured.

[0141] The method for preparing the liquid crystal lens may further include:

[0142] Step S470: forming a first dielectric layer and a third electrode layer on the first electrode layer; and

[0143] Step S480: forming a second dielectric layer and a fourth electrode layer on the second electrode layer.

[0144] Wherein, step S470 can be performed simultaneously with step S410 according to actual conditions, or it can be performed after step S410 is completed. Step S480 can be performed simultaneously with step S420 according to actual conditions, or it can be performed after step S420 is completed. The third electrode layer has the same structure as the fourth electrode layer, and the third electrode layer and the fourth electrode layer respectively include a plurality of second electrodes, and a second electrode is arranged between at least some of the groups and the liquid crystal layer (preferably, a plurality of second electrodes are distributed between each enlarged group and the liquid crystal layer; or, a plurality of second electrodes are distributed between each group and the liquid crystal layer; or, a plurality of second electrodes are distributed between each enlarged group and the liquid crystal layer, and the second electrodes and the first electrodes in the enlarged group have a first spacing in the optical axis direction, and the first electrodes in the central group are arranged in two layers, and the first electrodes in the two layers are alternately arranged in the first direction, and the projections of the first electrodes of the two layers in the first direction are tangent, and a dielectric layer is arranged between the first electrodes of the two layers, and the first electrodes in the two layers have a second spacing in the optical axis direction, and the second spacing is greater than the first spacing). The second electrode between the liquid crystal layer and a group and the first electrode in the group are alternately arranged in a first direction, the second electrode and the first electrode adjacent to it partially overlap, the first direction is perpendicular to the optical axis, and in this embodiment, the first direction is from the optical axis to the edge of the liquid crystal lens. The first electrode is configured to output a driving voltage, and the second electrode is used as a floating electrode.

[0145] The method for preparing the liquid crystal lens may further include:

[0146] Step S791: forming a first liquid crystal alignment layer on the first substrate, and rubbing and aligning the first common electrode layer from the side thereof to the side thereof. Step S791 may be performed, for example, after step S470, and the first liquid crystal alignment layer may be formed, for example, by coating polyimide on the surface of the first electrode layer or the third electrode layer.

[0147] Step S792: forming a second liquid crystal alignment layer on the second substrate, and rubbing and aligning the second liquid crystal alignment layer along the side where the second common electrode layer is located toward the side where the second electrode layer is located. Step S792 can be performed, for example, after step S480, and the second liquid crystal alignment layer can be formed, for example, by coating polyimide on the surface of the second electrode layer or the fourth electrode layer.

[0148] Finally, it should be noted that the above description is only an embodiment of the present invention and is not intended to limit the present invention. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art can still modify the technical solutions described in the aforementioned embodiments or replace some of the technical features therein by equivalents. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A liquid crystal lens having an optical axis, the liquid crystal lens comprising: A first substrate having a first half area and a second half area, wherein the first half area and the second half area are respectively arranged on both sides of the optical axis; a second substrate having a third half area and a fourth half area, wherein the third half area and the fourth half area are respectively arranged on both sides of the optical axis, and the third half area is opposite to the first half area, and the fourth half area is opposite to the second half area; a liquid crystal layer, disposed between the first substrate and the second substrate; A first electrode layer, disposed between the first half region and the liquid crystal layer; A first common electrode layer is disposed between the second half region and the liquid crystal layer; a second electrode layer, disposed between the fourth half region and the liquid crystal layer, wherein the second electrode layer has the same structure as the first electrode layer; A second common electrode layer is disposed between the third half region and the liquid crystal layer, wherein the second common electrode layer has the same structure as the first common electrode layer; Wherein, the first electrode layer and the second electrode layer respectively include a plurality of first electrodes, the plurality of first electrodes in the first electrode layer are spaced from the optical axis to the edge of the liquid crystal lens and are divided into a plurality of groups, the plurality of first electrodes in the second electrode layer are spaced from the optical axis to the edge of the liquid crystal lens and are divided into a plurality of groups, each group of first electrodes has a preset electrode sampling rate, and the electrode sampling rate of the group close to the optical axis is greater than the electrode sampling rate of the group far from the optical axis; The electrode sampling rate refers to the number of first electrodes contained in the optical path difference provided by the liquid crystal lens for each wavelength.

2. The liquid crystal lens according to claim 1, wherein: The plurality of first electrodes in the first electrode layer are divided into a plurality of regions, and the plurality of first electrodes in the second electrode layer are divided into a plurality of regions, wherein the regions have a preset width; Each of the groups comprises at least one region, and different groups may comprise the same or different numbers of regions; In the same group: the electrode sampling rate of each area is the same.

3. The liquid crystal lens according to claim 2, wherein: The width of the zone is (√i- √i-1)W1; Wherein, i is the ranking number of the corresponding area in the first electrode layer or the second electrode layer, and the ranking number is counted from the area closest to the optical axis in the first electrode layer or the second electrode layer toward the edge of the liquid crystal lens and starts from 1; W1 is the width of the area closest to the optical axis in the first electrode layer or the second electrode layer.

4. The liquid crystal lens according to claim 2, wherein: A third electrode layer is disposed between the first electrode layer and the liquid crystal layer, and a first dielectric layer is disposed between the first electrode layer and the third electrode layer; a fourth electrode layer is disposed between the second electrode layer and the liquid crystal layer, and a second dielectric layer is disposed between the second electrode layer and the fourth electrode layer; wherein the third electrode layer and the fourth electrode layer have the same structure; Among the multiple groups of the first electrode layer: the group closest to the optical axis is the central group, and the other groups are expanded groups; among the multiple groups of the second electrode layer: the group closest to the optical axis is the central group, and the other groups are expanded groups; The third electrode layer and the fourth electrode layer respectively include a plurality of second electrodes, the second electrodes are distributed between at least part of the groups and the liquid crystal layer, the second electrodes between the liquid crystal layer and a group and the first electrodes in the group are alternately arranged in a first direction, the second electrodes partially overlap with the first electrodes adjacent to them, and the first direction is perpendicular to the optical axis; The first electrode is configured to output a driving voltage, and the second electrode is configured to output a coupling voltage through capacitive coupling of two first electrodes partially overlapping with the second electrode.

5. The liquid crystal lens according to claim 4, wherein: The plurality of second electrodes are distributed between each of the enlarged groups and the liquid crystal layer.

6. The liquid crystal lens according to claim 4, wherein: The plurality of second electrodes are distributed between each of the groups and the liquid crystal layer.

7. The liquid crystal lens according to claim 6, wherein: In the center group: The overlapping width of each first electrode and the corresponding second electrode is the same; or, The overlapping widths of each first electrode and the corresponding second electrode are different, and the overlapping widths of the first electrode close to the optical axis and the corresponding second electrode are greater than the overlapping widths of the first electrode far from the optical axis and the corresponding second electrode; or, The overlapping area ratio of each second electrode and the corresponding first electrode is the same.

8. The liquid crystal lens according to claim 4, wherein: The plurality of second electrodes are distributed between each of the enlarged groups and the liquid crystal layer; The first electrodes in the central group are arranged in two layers, and the first electrodes in the two layers are arranged alternately in a first direction, and a dielectric layer is arranged between the first electrodes in the two layers.

9. The liquid crystal lens according to claim 8, wherein: The second electrode and the first electrode in the expanded group have a first spacing in the optical axis direction; the first electrodes in the two layers have a second spacing in the optical axis direction, and the second spacing is greater than the first spacing; the projections of the first electrodes of the two layers in the first direction are tangent.

10. The liquid crystal lens according to any one of claims 5 to 7, wherein: The plurality of first electrodes in the first electrode layer are arranged at equal intervals from the edge of the optical axis to the first half region, and the plurality of first electrodes in the second electrode layer are arranged at equal intervals from the edge of the optical axis to the fourth half region.

11. The liquid crystal lens according to any one of claims 5 to 9, wherein: The liquid crystal lens further comprises a circuit bus, wherein the circuit bus comprises a plurality of circuit branches, wherein the plurality of circuit branches respectively provide different voltages, and the number of the circuit branches is the same as the number of the first electrodes included in one area of ​​the central group; In the central group: the plurality of first electrodes in each of the regions correspond one-to-one to and are electrically connected to the plurality of circuit branches; In the expanded group: the first electrode is connected to a corresponding circuit branch according to a target coupling voltage of a second electrode coupled thereto.

12. The liquid crystal lens according to claim 11, wherein: The circuit bus further includes a very large voltage branch and / or a very small voltage branch; In the expanded group: the first electrode is connected to a corresponding circuit branch, a maximum voltage branch or a minimum voltage branch according to a target coupling voltage of a second electrode coupled thereto.

13. The liquid crystal lens according to claim 1, wherein: The surface areas of the first electrodes in the same group are the same; In the first electrode layer: the surface areas of the first electrodes in different groups are different; in the second electrode layer: the surface areas of the first electrodes in different groups are different; The surface area of ​​the first electrodes in the group close to the optical axis is smaller than the surface area of ​​the first electrodes in the group far from the optical axis.

14. The liquid crystal lens according to claim 1, wherein: In the same group: the line width of the first electrode close to the optical axis is greater than the line width of the first electrode far from the optical axis; In two adjacent groups: the line width of the first electrode closest to the optical axis in the group far from the optical axis is greater than the line width of the first electrode farthest from the optical axis in the group close to the optical axis.

15. The liquid crystal lens according to claim 1, wherein: A first liquid crystal alignment layer is disposed on a side of the liquid crystal layer close to the first substrate, and the first liquid crystal alignment layer is rubbed and aligned along a side where the first common electrode layer is located toward a side where the first electrode layer is located; A second liquid crystal alignment layer is disposed on a side of the liquid crystal layer close to the second substrate, and the second liquid crystal alignment layer is rubbed and aligned along a side where the second common electrode layer is located toward a side where the second electrode layer is located.

16. A method for preparing a liquid crystal lens, comprising: forming a first electrode layer on the first half area of ​​the first substrate, and forming a first common electrode layer on the second half area of ​​the first substrate; forming a second common electrode layer on the third half region of the second substrate, and forming a second electrode layer on the fourth half region of the second substrate; Arranging spacers on the first substrate or the second substrate; forming a liquid crystal layer on one of the first substrate or the second substrate; forming a plastic frame on the other of the first substrate and the second substrate; and Assemble the first substrate and the second substrate so that the first half of the first substrate faces the third half of the second substrate, and the second half of the first substrate faces the fourth half of the second substrate, and cure the glue frame; The first common electrode layer and the second common electrode layer have the same structure, and the first electrode layer and the second electrode layer have the same structure; the first electrode layer and the second electrode layer respectively include a plurality of first electrodes, the plurality of first electrodes in the first electrode layer are spaced from the optical axis of the liquid crystal lens to the edge of the liquid crystal lens and are divided into a plurality of groups, the plurality of first electrodes in the second electrode layer are spaced from the optical axis to the edge of the liquid crystal lens and are divided into a plurality of groups, each group of first electrodes has a preset electrode sampling rate, and the electrode sampling rate of the group close to the optical axis is greater than the electrode sampling rate of the group far from the optical axis; The electrode sampling rate refers to the number of first electrodes contained in the optical path difference provided by the liquid crystal lens for each wavelength.

17. The preparation method according to claim 16, further comprising: forming a first dielectric layer and a third electrode layer on the first electrode layer; and forming a second dielectric layer and a fourth electrode layer on the second electrode layer; Among the multiple groups of the first electrode layer: the group closest to the optical axis is the central group, and the other groups are expanded groups; among the multiple groups of the second electrode layer: the group closest to the optical axis is the central group, and the other groups are expanded groups; The third electrode layer and the fourth electrode layer have the same structure, the third electrode layer and the fourth electrode layer respectively include a plurality of second electrodes, the second electrodes are distributed between at least part of the groups and the liquid crystal layer, the second electrodes between the liquid crystal layer and a group and the first electrodes in the group are alternately arranged in a first direction, the second electrodes partially overlap with the first electrodes adjacent to them, and the first direction is perpendicular to the optical axis; The first electrode is configured to output a driving voltage, and the second electrode is configured to output a coupling voltage through capacitive coupling of two first electrodes partially overlapping with the second electrode.

18. The preparation method according to claim 17, wherein: The plurality of second electrodes are distributed between each of the enlarged groups and the liquid crystal layer.

19. The preparation method according to claim 17, wherein: The plurality of second electrodes are distributed between each of the groups and the liquid crystal layer.

20. The preparation method according to claim 17, wherein: The plurality of second electrodes are distributed between each of the enlarged groups and the liquid crystal layer; The first electrodes in the central group are arranged in two layers, and the first electrodes in the two layers are arranged alternately in a first direction, and a dielectric layer is arranged between the first electrodes in the two layers.

21. The preparation method according to claim 20, wherein: The second electrode and the first electrode in the expanded group have a first spacing in the optical axis direction; the first electrodes in the two layers have a second spacing in the optical axis direction, and the second spacing is greater than the first spacing; the projections of the first electrodes of the two layers in the first direction are tangent.

22. The preparation method according to claim 16, further comprising: forming a first liquid crystal alignment layer on the first substrate, and rubbing and aligning the liquid crystal from the side where the first common electrode layer is located to the side where the first electrode layer is located; and A second liquid crystal alignment layer is formed on the second substrate, and rubbed and aligned along the side where the second common electrode layer is located toward the side where the second electrode layer is located.

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