CN220709504U - Liquid crystal Fresnel lens and electronic product - Google Patents

Abstract

The utility model belongs to the technical field of liquid crystal Fresnel lenses, and particularly relates to a liquid crystal Fresnel lens and an electronic product. The utility model provides a liquid crystal Fresnel lens, which comprises a first substrate, a first electrode layer, a first orientation layer, a liquid crystal layer, a second orientation layer, a second electrode layer and a second substrate which are sequentially laminated; the first electrode layer is a surface electrode; the second electrode layer comprises a plurality of electrode units which are sequentially arranged from the center of the second electrode layer to the edge; the electrode unit comprises a potential gradient distribution wire and a plurality of concentric circular arcs, wherein a first position for receiving a first driving voltage and a second position for receiving a second driving voltage are arranged on the potential gradient distribution wire; one end of the concentric arc line is connected with the potential gradient distribution wire in the electrode unit, and the opposite end is suspended; the utility model can obviously improve the potential control precision of the liquid crystal Fresnel lens.

Description

Liquid crystal Fresnel lens and electronic product

Technical Field

The utility model relates to the technical field of liquid crystal Fresnel lenses, in particular to a liquid crystal Fresnel lens and an electronic product.

Background

Because of the advantage of electronically controlled focusing, liquid crystal lenses are often used to facilitate adjustment of the focal length of the lens in applications where adjustment of the focal length of the lens is desired. But when the lens size is large, the driving voltage for driving the liquid crystal lens may be excessively high. For this purpose, a liquid crystal fresnel lens is currently used to reduce the driving voltage of the liquid crystal lens. The prior liquid crystal Fresnel lens consists of a plurality of electrode pairs, each electrode pair comprises two concentric ring electrodes, one electrode pair can control the electric field distribution of the corresponding Fresnel zone region, and the complete liquid crystal Fresnel lens is formed by the plurality of electrode pairs. Although such an electrode structure can simulate the optical effect of the fresnel lens to some extent, the electrode structure is inferior in the degree of accuracy of controlling the electric potential distribution between the electrode pairs, and the electric potential distribution cannot be made to satisfy the exact parabolic distribution, resulting in the poor optical effect of the obtained fresnel liquid crystal lens.

Disclosure of Invention

In view of the above, the embodiment of the utility model provides a liquid crystal Fresnel lens and an electronic product, which are used for solving the technical problem of low control precision of potential distribution of the existing liquid crystal Fresnel lens.

The technical scheme adopted by the utility model is as follows:

in a first aspect, the utility model provides a liquid crystal fresnel lens, comprising a first substrate, a first electrode layer, a first alignment layer, a liquid crystal layer, a second alignment layer, a second electrode layer and a second substrate which are sequentially stacked;

the first electrode layer is a surface electrode;

the second electrode layer comprises a plurality of electrode units which are sequentially arranged from the center of the second electrode layer to the edge;

the electrode unit comprises a potential gradient distribution wire and a plurality of concentric circular arcs, wherein a first position for receiving a first driving voltage and a second position for receiving a second driving voltage are arranged on the potential gradient distribution wire; one end of the concentric arc line is connected with the potential gradient distribution wire in the electrode unit, and the opposite end is suspended;

the connection positions of the concentric circular arcs and the potential gradient distribution wires are located between the first positions and the second positions of the potential gradient distribution wires, the connection positions of the potential gradient distribution wires and the concentric circular arcs are set to be reference positions, and the resistance values between the reference positions of the potential gradient distribution wires and the first positions and the distances between the reference positions and the first positions along the radial direction of the second electrode layer are parabolic.

Preferably, the potential gradient distribution wire comprises a plurality of extension sections and a plurality of connection sections, and opposite ends of the connection sections are respectively connected with two adjacent extension sections.

Preferably, the land is disposed along a radial direction of the second electrode layer.

Preferably, the connection sections are staggered along the circumferential direction of the second electrode layer.

Preferably, the plurality of extension sections are arc-shaped.

Preferably, the distance between adjacent extension sections is 100 μm or less.

Preferably, the width of the portion of the potential gradient distribution wire between the first position and the second position is the same, and the length between each reference position of the potential gradient distribution wire and the first position is parabolic in distribution with the distance between each reference position and the first position in the radial direction of the second electrode layer.

Preferably, a high-resistance film or a high-dielectric constant layer is provided between the second electrode layer and the second alignment layer, or

A high-resistance film or a high-dielectric constant layer is provided between the second electrode layer and the second substrate.

Preferably, the surface electrode and each of the electrode units deflect liquid crystal in the liquid crystal layer to form a liquid crystal fresnel lens under the driving of the first driving voltage and the second driving voltage.

In a second aspect, the present utility model further provides an electronic product, including a control circuit and the liquid crystal fresnel lens according to the first aspect, where the control circuit is electrically connected to the liquid crystal fresnel lens.

The beneficial effects are that: the liquid crystal Fresnel lens and the electronic product correspondingly realize the optical function of each annular zone area of the Fresnel lens by utilizing the electric field distribution generated by the electrode units which are sequentially arranged from the center to the edge on the second electrode layer. The potential gradient distribution leads are used for generating potential which is distributed in a gradient manner along the radial direction for each electrode unit, the potential on the potential gradient distribution leads is led to each area of the liquid crystal Fresnel lens by utilizing concentric circular arcs, and the high-precision parabolic potential distribution is obtained by arranging the resistance value between each reference position of the potential gradient distribution leads and the first position and the parabolic distribution of the distance between each reference position and the first position along the radial direction of the second electrode layer, so that the annular area of the liquid crystal layer controlled by the electric field of each electrode unit can reach the optical effect closest to the annular area of the ideal Fresnel lens. The liquid crystal Fresnel lens can accurately control the potential distribution of the liquid crystal Fresnel lens only by controlling two driving voltages, so that the liquid crystal Fresnel lens has good optical effect, simple control mode and lower product cost.

Drawings

In order to more clearly illustrate the technical solution of the embodiments of the present utility model, the drawings required to be used in the embodiments of the present utility model will be briefly described, and it is within the scope of the present utility model to obtain other drawings according to these drawings without inventive effort for a person skilled in the art.

FIG. 1 is a cross-sectional view of a liquid crystal Fresnel lens of the present utility model;

FIG. 2 is a schematic diagram of a second electrode layer in the liquid crystal Fresnel lens of the present utility model;

FIG. 3 is a schematic view showing the structure of a first electrode unit in the liquid crystal Fresnel lens of the present utility model;

FIG. 4 is a schematic diagram of the structure of the potential distribution gradient wire of the first electrode unit in the liquid crystal Fresnel lens of the present utility model;

FIG. 5 is a schematic diagram of a concentric circular arc line structure of a first electrode unit in a liquid crystal Fresnel lens of the present utility model;

FIG. 6 is a schematic diagram showing the structure of a second electrode unit in the liquid crystal Fresnel lens of the present utility model;

FIG. 7 is a schematic diagram of the structure of the potential distribution gradient wire of the second electrode unit in the liquid crystal Fresnel lens of the present utility model;

FIG. 8 is a schematic diagram of a concentric circular arc line structure of a second electrode unit in the liquid crystal Fresnel lens of the present utility model;

FIG. 9 is a schematic diagram showing the structure of a third electrode unit in the liquid crystal Fresnel lens of the present utility model;

FIG. 10 is a schematic diagram of the structure of the potential distribution gradient wire of the third electrode unit in the liquid crystal Fresnel lens of the present utility model;

FIG. 11 is a schematic view of a concentric circular arc line structure of a third electrode unit in the liquid crystal Fresnel lens of the present utility model;

FIG. 12 is a schematic diagram of the structure of a potential distribution gradient wire of the present utility model;

parts and numbers in the figure:

the first substrate 10, the first electrode layer 20, the first alignment layer 30, the liquid crystal layer 40, the second alignment layer 50, the second electrode layer 60, the second substrate 70, the electrode unit 61, the potential gradient distribution wire 611, the first position 612, the second position 613, the concentric arc 614, the reference position 615, the extension 616, the joining section 617.

Detailed Description

In order to make the objects, technical solutions and advantages of the embodiments of the present utility model more clear, the technical solutions of the embodiments of the present utility model will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present utility model. It is noted that relational terms such as first and second, and the like are used solely to distinguish one entity or action from another entity or action without necessarily requiring or implying any actual such relationship or order between such entities or actions. In the description of the present utility model, it should be understood that the terms "center," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," and the like indicate orientations or positional relationships based on the orientation or positional relationships shown in the drawings, merely to facilitate description of the present application and simplify the description, and do not indicate or imply that the devices or elements referred to must have a specific orientation, be configured and operated in a specific orientation, and thus should not be construed as limiting the present utility model. Moreover, the terms "comprises," "comprising," or any other variation thereof, are intended to cover a non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements does not include only those elements but may include other elements not expressly listed or inherent to such process, method, article, or apparatus. Without further limitation, an element defined by the phrase "comprising … …" does not exclude the presence of other like elements in a process, method, article or apparatus that comprises the element. If not conflicting, the embodiments of the present utility model and the features of the embodiments may be combined with each other, which are all within the protection scope of the present utility model.

Example 1

The utility model provides a liquid crystal Fresnel lens. A fresnel lens is a lens obtained by maintaining the curvature of its surface constant in the design of an optical lens, but reducing the thickness of its surface during processing, based on the principle that the curvature of the optical surface in optical imaging determines imaging characteristics. The lens designed in this way can still collect light rays and can focus the light rays incident on the surface of the lens to a focal point.

Because the spherical lens can be regarded as a plurality of discontinuous split bodies in the actual processing and application of the lens, and redundant parts among the split bodies are removed, the original curvature of the surface of the spherical lens is kept unchanged in the processing process, and the deflection of light is not influenced after the redundant parts are removed. The aforementioned function of several discrete split bodies is achieved by a central circle on the fresnel lens and a series of concentric rings. The liquid crystal fresnel lens of the present embodiment utilizes a certain regular deflection of the liquid crystal layer 40 under the action of an electric field to realize the function of each concentric zone of the fresnel lens, thereby realizing an optical effect equivalent to that of the fresnel lens by utilizing the liquid crystal lens.

As shown in fig. 1, the liquid crystal fresnel lens of the present embodiment mainly includes a first substrate 10, a first electrode layer 20, a first alignment layer 30, a liquid crystal layer 40, a second alignment layer 50, a second electrode layer 60, and a second substrate 70.

Wherein the first substrate 10 and the second substrate 70 are respectively positioned at opposite sides of the liquid crystal layer 40. Wherein the first substrate 10 and the second substrate 70 function as supports. As an alternative but advantageous embodiment, the first substrate 10 and the second substrate 70 are implemented as transparent substrates. In order to better support, the first substrate 10 and the second substrate 70 in this embodiment may be made of a transparent material having a certain strength and rigidity, wherein the transparent material includes, but is not limited to, plastic and glass.

In this embodiment, the first electrode layer 20 is located on a side of the first substrate 10 facing the liquid crystal layer 40, and the second electrode layer 60 is located on a side of the second substrate 70 facing the liquid crystal layer 40. Thus, the first substrate 10 may serve as a carrier for the first electrode layer 20, while the second substrate 70 serves as a carrier for the second electrode layer 60. As an alternative but advantageous embodiment, the first electrode layer 20 may be plated on the first substrate 10 and the second electrode layer 60 may be plated on the second substrate 70 in this example. In this embodiment, the first alignment layer 30 and the second alignment layer 50 are also provided at positions on both sides of the liquid crystal layer 40.

The first electrode layer 20 in this embodiment is in the form of a planar electrode, so that when a voltage is applied to the surface electrode of the first electrode layer 20, the first electrode layer 20 forms an equipotential surface.

As shown in fig. 2, the second electrode layer 60 in this embodiment includes a plurality of electrode units 61 sequentially arranged from the center to the edge of the second electrode layer 60;

since the concentric annular bands of the fresnel lens are arranged from inside to outside, each of the electrode units 61 in the second electrode layer 60 of the present embodiment corresponds to one of the aforementioned concentric annular bands or central annular bands of the fresnel lens. The arrangement of the electrode units 61 in the second electrode layer 60 is thus identical to the central circular or concentric annular arrangement of the fresnel lens, i.e. a ring-by-ring arrangement from inside to outside.

The present embodiment controls the electric field distribution of the liquid crystal layer 40 described above by the electrode unit 61 in the second electrode layer 60. One of the electrode units 61 is used for controlling the electric field distribution of one zone area in the liquid crystal layer 40, so that the liquid crystal molecules in the zone area deflect according to a certain rule, and the phase delay of the light passing through the zone area of the liquid crystal layer 40 is the same as the phase delay of the light passing through the concentric zone of the fresnel lens, thereby realizing the optical function of one concentric zone in the fresnel lens.

Since each liquid crystal molecule zone region in the present embodiment can realize the optical function of the corresponding zone region in the fresnel lens, and the arrangement mode of the electrode units 61 is the same as that of the concentric zones of the fresnel liquid crystal lens, under the combined action of all the electrode units 61, all the zone regions in the middle layer of the liquid crystal form a complete liquid crystal fresnel lens, which has the same overall optical effect as that of the common liquid crystal fresnel lens.

Since the realization of the overall function of the liquid crystal fresnel lens depends on the realization of the respective concentric zones, accurate control of the electric field distribution of each liquid crystal layered zone has an important influence on the optical effect of the liquid crystal fresnel lens. The prior art method for controlling the electric field distribution in the annulus region of the liquid crystal layer 40 adopts a mode of electrode pairs, and the method cannot accurately control the electric field in each position of the annulus region although the number of driving voltages is small. In this regard, as shown in fig. 3, 6 and 9, the electrode unit 61 includes a potential gradient distribution wire 611 and a plurality of concentric circular arcs 614 in the present embodiment. The potential gradient distribution wire 611 is provided with a first position 612 for receiving a first driving voltage and a second position 613 for receiving a second driving voltage; one end of the concentric arc 614 is connected with the potential gradient distribution wire 611 in the electrode unit 61, and the opposite end is suspended;

as shown in fig. 4, 7 and 10, the potential gradient distribution wire 611 is made of a conductive wire having a certain resistance, or a thin wire which is plated on the surface of the second substrate 70 and has a certain resistance and can conduct electricity. As an alternative but advantageous embodiment, the potential gradient distribution wire 611 in this example can also be made of a transparent conductive material, so that the light transmission effect of the liquid crystal fresnel lens is not affected. Wherein the transparent conductive material includes, but is not limited TO, ito electrode material, FTO electrode material, AZO electrode material, IGZO electrode material, ZO electrode material, and the like. The concentric arc 614 refers to an arc having the same center. The concentric circular arcs can also be made of transparent materials in order to improve the light transmission effect of the liquid crystal lens.

The liquid crystal fresnel lens of the present embodiment may apply the first driving voltage and the second driving voltage to the first position 612 and the second position 613 of the electric potential gradient distribution wire 611, respectively, and the electric potential on the electric potential gradient distribution wire 611 may exhibit a gradient change, for example, the electric potential gradually becomes smaller in the process from the first position 612 to the second position 613, and the electric potential gradually becomes larger in the process from the first position 612 to the second position 613.

As shown in fig. 5, 8 and 11, when one end of each concentric arc 614 in the present embodiment is connected to the potential distribution wire and the opposite end is suspended, the potential on the same concentric arc 614 is equal everywhere, and the potential on the concentric arc is equal to the potential on the potential gradient distribution wire 611 at the position where the concentric arc 614 is connected to the potential gradient distribution wire 611.

Thus, by setting the connection positions of the respective concentric circular arcs 614 and the potential gradient distribution wire 611, the potential on the respective concentric circular arcs 614 can be controlled, and by the extension of the concentric circular arcs 614 in the circumferential direction (Y direction in fig. 2), the potential distribution at the positions where the concentric circular arcs pass in one fresnel zone region can be precisely controlled.

As shown in fig. 1, in the present embodiment, the connection position of the concentric circular arcs 614 and the potential gradient distribution wire 611 is located between the first position 612 and the second position 613 of the potential gradient distribution wire 611, the connection position of the potential gradient distribution wire 611 and each concentric circular arc 614 is set as a reference position 615, and the resistance value between each reference position 615 and the first position 612 of the potential gradient distribution wire 611 and the distance from each reference position 615 to the first position 612 in the radial direction (X direction in fig. 1) of the second electrode layer 60 are parabolic. The surface electrodes and the respective electrode units 61 deflect the liquid crystal in the liquid crystal layer 40 to form a liquid crystal fresnel lens under the driving of the first and second driving voltages.

The parabolic distribution of the resistance value between each reference position 615 to the first position 612 of the potential gradient distribution wire 611 and the distance between each reference position 615 to the first position 612 in the radial direction of the second electrode layer 60 means that a rectangular coordinate system in which a curve representing the correspondence between the resistance value between each reference position 615 to the first position 612 of the potential gradient distribution wire and the distance between each reference position 615 to the first position 612 in the radial direction of the second electrode layer 60 is parabolic is established with the resistance value between each reference position 615 to the first position 612 of the potential gradient distribution wire and the distance between each reference position 615 to the first position 612 in the radial direction of the second electrode layer 60 as coordinate axes, respectively.

Since the electric potential of a certain position on the electric potential gradient distribution wire 611 depends on the magnitude of the resistance value between the position to the first position after the electrode unit 61 of the present embodiment is loaded with the first driving voltage and the second driving voltage at the first position 612 and the second position 613, respectively, the present embodiment precisely controls the electric field distribution of the endless belt region corresponding to the electrode unit 61 by setting the connection position of each concentric arc 614 to the electric potential gradient distribution wire 611 and the distance between each concentric arc 614 and the first position 612 in the radial direction. Since the foregoing structure is adopted, the electric potential on each concentric arc 614 can be precisely controlled, and the radial position of each arc can be precisely controlled, the control of the electric potential distribution of the endless belt region corresponding to the electrode unit 61 can be simply and precisely achieved.

Since the electric resistance value between each reference position 615 and the first position 612 of the electric potential gradient distribution wire 611 and the distance between each reference position 615 and the first position 612 along the radial direction of the second electrode layer 60 are parabolic, the electric potential distribution of the annular zone region in the liquid crystal layer 40 controlled by each electrode unit 61 is also parabolic, which makes the phase delay of the light passing through the annular zone region of the liquid crystal layer 40 be precise parabolic after the liquid crystal molecules in the liquid crystal layer 40 deflect under the action of the electric field, which is the same as the modulation effect of the annular zone of the ideal fresnel lens on the light.

As a preferred embodiment, the width of the portions of the potential distribution gradient wire located at the first position 612 and the second position 613 is the same in this example.

In the case where the width of the portion of the potential gradient distribution wire 611 between the first position 612 and the second position 613 is the same, the resistance value between each reference position 615 to the first position 612 on the potential gradient distribution wire 611 is proportional to the length of the potential distribution wire from each reference position 615 to the first position 612.

Therefore, the present embodiment can control the electric potential on each concentric arc 614 by controlling the length of the electric potential distribution wire between the reference position 615 to the first position on the electric potential distribution wire, thereby further simplifying the electric field distribution control of the liquid crystal fresnel lens zone region and more easily obtaining an accurate parabolic electric field distribution.

As shown in fig. 12, in the present embodiment, the potential gradient distribution wire 611 may specifically take the following structural form: the potential gradient distribution wire 611 includes a plurality of extension sections 616 and a plurality of connection sections 617, opposite ends of the connection sections 617 being respectively connected to two adjacent extension sections 616. Wherein the connection segments may be arranged in a radial direction of the second electrode layer 60 in order to connect two adjacent extension segments 616.

The present embodiment can be further modified based on the foregoing structure to stagger the connection sections along the circumferential direction of the second electrode layer 60, so that the potential gradient distribution wires 611 are bent back and forth, which can significantly increase the length of the potential distribution wires in a unit distance in the radial direction, thereby providing the accuracy of controlling the potential of the concentric arc lines 614 by using the potential of the connection position of the concentric arc lines 614.

The number of extension segments 616 may be rounded as an alternative but advantageous embodiment. It will be appreciated that in other embodiments the extension 616 may be provided in any other shape, without limitation.

As an alternative but advantageous embodiment, the spacing between adjacent extension segments 616 is less than or equal to 100 μm. The pitch between adjacent concentric circular arcs 614 in the rear electrode unit 61 is also 100 μm or less with the aforementioned structure. The present embodiment realizes high-precision potential distribution by setting the spacing between the extension segments 616 within 100 μm, eliminating the potential step between the adjacent concentric circular arcs 614, so that an ideal potential distribution can be formed in the corresponding fresnel zone region without using a high-impedance film, and the influence of the poor stability of the high-impedance film or the high-dielectric constant material on the stability of the liquid crystal lens effect can be successfully eliminated.

As a preferred embodiment, the present embodiment provides a high-resistance film or a high-dielectric constant layer in a liquid crystal fresnel lens.

The high-resistance film or the high-dielectric constant layer may be provided between the second electrode layer 60 and the second alignment layer, or may be provided between the second electrode layer 60 and the second substrate 70. The potential between adjacent concentric circular arcs 614 may be made smoother by employing a high impedance film or a high dielectric constant layer in the liquid crystal fresnel lens, thereby further improving the effect of the liquid crystal fresnel lens.

The following describes a method for driving your liquid crystal fresnel lens, let the first driving voltage be V1 and the second driving voltage be V2, the driving method includes the following steps:

s1: acquiring a liquid crystal linear working interval of a liquid crystal Fresnel lens;

the liquid crystal linear operation interval refers to a voltage interval in which the liquid crystal phase retardation amount and the driving voltage are in a linear relationship.

S2: obtaining a minimum voltage Vmin and a maximum voltage Vmax in the liquid crystal linear working interval according to the liquid crystal linear working interval;

s3: the voltage difference between V1 and V2 is adjusted according to the minimum voltage Vmin and the maximum voltage Vmax to adjust the focal power of the liquid crystal Fresnel lens, wherein Vmin is less than or equal to V1 and less than or equal to Vmax, and Vmin is less than or equal to V2 and less than or equal to Vmax.

This step can adjust the optical power of the liquid crystal fresnel lens by adjusting the difference between V1 and V2. V1 can be kept unchanged during specific adjustment, and the size of V2 can be adjusted; v1 can be kept unchanged, and the size of V2 can be adjusted; the magnitudes of V1 and V2 can also be changed simultaneously. When V1 is kept unchanged and V2 is adjusted in size, v1=vmin or v1=vmax may be set and V2 is adjusted in size; when V2 is kept unchanged and V1 is resized, v2=vmin or v2=vmax may be set and V1 is resized. As can be seen from the foregoing, the liquid crystal fresnel lens of the present embodiment can simply and precisely perform adjustment of optical power by controlling only two driving voltages.

Example 2

The embodiment provides an electronic product, which comprises a control circuit and the liquid crystal Fresnel lens of the first aspect, wherein the control circuit is electrically connected with the liquid crystal Fresnel lens. The electronic product includes, but is not limited to, an imaging device, a display device, a mobile phone, an AR device, a VR device, a naked eye 3D product, a wearable device, and the like.

In the foregoing, only the specific embodiments of the present utility model are described, and it will be clearly understood by those skilled in the art that, for convenience and brevity of description, the specific working processes of the systems, modules and units described above may refer to the corresponding processes in the foregoing method embodiments, which are not repeated herein. It should be understood that the scope of the present utility model is not limited thereto, and any equivalent modifications or substitutions can be easily made by those skilled in the art within the technical scope of the present utility model, and they should be included in the scope of the present utility model.

Claims (10)

1. The liquid crystal Fresnel lens is characterized by comprising a first substrate, a first electrode layer, a first orientation layer, a liquid crystal layer, a second orientation layer, a second electrode layer and a second substrate which are sequentially laminated;

the first electrode layer is a surface electrode;

the second electrode layer comprises a plurality of electrode units which are sequentially arranged from the center of the second electrode layer to the edge;

the electrode unit comprises a potential gradient distribution wire and a plurality of concentric circular arcs, wherein a first position for receiving a first driving voltage and a second position for receiving a second driving voltage are arranged on the potential gradient distribution wire; one end of the concentric arc line is connected with the potential gradient distribution wire in the electrode unit, and the opposite end is suspended;

the connection positions of the concentric circular arcs and the potential gradient distribution wires are located between the first positions and the second positions of the potential gradient distribution wires, the connection positions of the potential gradient distribution wires and the concentric circular arcs are set to be reference positions, and the resistance values between the reference positions of the potential gradient distribution wires and the first positions and the distances between the reference positions and the first positions along the radial direction of the second electrode layer are parabolic.

2. The liquid crystal fresnel lens of claim 1, wherein the potential gradient distribution wire comprises a plurality of extension segments and a plurality of joining segments, opposite ends of the joining segments being respectively connected to two adjacent extension segments.

3. The liquid crystal fresnel lens of claim 1, wherein the land sections are disposed in a radial direction of the second electrode layer.

4. The liquid crystal fresnel lens of claim 1, wherein the joining sections are staggered in the circumferential direction of the second electrode layer.

5. The liquid crystal fresnel lens of claim 1, wherein the plurality of extension segments are circular arcs.

6. The liquid crystal fresnel lens of claim 5, wherein the spacing between adjacent ones of the extended segments is 100 μm or less.

7. The liquid crystal fresnel lens according to claim 1, wherein the width of the portion of the electric potential gradient distribution wire between the first position and the second position is the same, and the lengths between the respective reference positions of the electric potential gradient distribution wire to the first position are parabolic in distribution with the distances from the respective reference positions to the first position in the radial direction of the second electrode layer.

8. The liquid crystal fresnel lens according to any one of claims 1-7, characterized in that a high-resistance film or a high dielectric constant layer, or is provided between the second electrode layer and the second alignment layer

A high-resistance film or a high-dielectric constant layer is provided between the second electrode layer and the second substrate.

9. The liquid crystal fresnel lens of any one of claims 1-7, wherein the face electrode and each of the electrode units deflect liquid crystal in the liquid crystal layer under the drive of the first and second drive voltages to form a liquid crystal fresnel lens.

10. Electronic product, characterized in that it comprises a control circuit and a liquid crystal fresnel lens according to any one of claims 1 to 9, said control circuit being electrically connected to said liquid crystal fresnel lens.