A segmented spiral based fresnel patterned electrode and a fresnel liquid crystal lens

Abstract

The application relates to the technical field of liquid crystal optical devices, and discloses a Fresnel patterned electrode based on segmented spirals and a Fresnel liquid crystal lens. The electrode comprises a Fresnel ring belt, at least one concentric circular electrode is arranged in the Fresnel ring belt, and the concentric circular electrodes all have the same center; the electrode further comprises a spiral electrode which is continuously extended outward from the center and spirally wound, the spiral electrode is cut into a plurality of segmented spiral electrodes at the junction with the Fresnel ring belt; the concentric circular electrode is electrically connected with the segmented spiral electrode, and is used for extending the voltage distribution on the segmented spiral electrode along the circumferential direction to cover the entire Fresnel ring belt. The application can realize voltage distribution and phase distribution close to a parabola, improve phase control precision, and thus improve imaging definition. By combining the spiral electrode with the concentric circular electrode, the design freedom of the width of the concentric circular electrode is significantly improved, which helps to reduce diffraction loss. Meanwhile, the structure reduces the difficulty of patterned preparation of a large-size spiral electrode, and improves the device processing yield.

Description

Technical Field

[0001] This invention relates to the field of liquid crystal optical device technology, and in particular to a Fresnel patterned electrode based on a segmented spiral and a Fresnel liquid crystal lens. Background Technology

[0002] Liquid crystal lenses are a type of tunable focusing optical device that utilizes the electro-optic effect of liquid crystal materials to achieve phase control. Compared with traditional solid-state lenses, liquid crystal lenses have advantages such as simple structure, low power consumption, no mechanical moving parts, and electrically adjustable focal length. Therefore, they have broad application prospects in fields such as 3D display, machine vision, microscopic imaging, augmented reality, and optical communication.

[0003] In the implementation of liquid crystal lenses, Fresnel patterned electrodes based on segmented spirals have attracted widespread attention due to their ability to achieve a large optical focal length adjustment range with relatively thin device thicknesses. Segmented spiral Fresnel patterned electrodes typically achieve lens functionality by constructing a radially distributed phase distribution within the liquid crystal layer. Ideally, this phase distribution should be approximately parabolic to achieve good focusing performance. To generate the desired spatial electric field distribution within the liquid crystal layer, researchers typically design patterned electrode structures of specific shapes on the substrate. Common implementations include concentric ring electrode structures, multi-electrode segmented driving structures, and resistor network driving structures. These structures achieve phase modulation by applying different voltages between different electrodes to form an approximately continuously varying electric field distribution within the liquid crystal layer. However, with the continuous increase in the aperture size of liquid crystal lenses and the increasing demands for phase modulation accuracy, traditional electrode structures are gradually revealing the following limitations in practical applications: (i) Traditional multi-electrode segmented driving structures typically require a large number of independent electrodes and complex driving circuits. As the lens aperture increases, the number of electrodes needs to be further increased in order to obtain a smoother phase distribution. This not only increases the fabrication complexity of the device, but also increases the complexity and cost of the driving system.

[0004] (ii) Some liquid crystal lenses employ a high-resistivity film structure to achieve continuous voltage distribution. While this method can reduce the number of driving electrodes to some extent, the electrical properties of the resistive film are easily affected by factors such as material uniformity, temperature changes, and processing errors, leading to unstable voltage distribution and consequently affecting the optical performance of the lens. Summary of the Invention

[0005] The present invention aims to at least improve one of the technical problems existing in the prior art. To this end, the present invention proposes a Fresnel patterned electrode based on a segmented spiral and a Fresnel liquid crystal lens.

[0006] The technical solution of the present invention is as follows: A segmented spiral-based Fresnel patterned electrode includes multiple Fresnel rings, each Fresnel ring including at least one concentric circular electrode, and each concentric circular electrode within all Fresnel rings having the same center. It also includes a spiral electrode that extends continuously from the inside out, which is cut at the junction of adjacent Fresnel rings to form multiple segmented spiral electrodes; Within the same Fresnel ring, the concentric circular electrode is electrically connected to the segmented spiral electrode to extend the voltage formed on the segmented spiral electrode in the circumferential direction of the Fresnel ring, so that the voltage distribution can cover the entire Fresnel ring.

[0007] In one possible technical solution, the segmented spiral electrodes can be rotated circumferentially at any angle. or, Mirroring operations based on a ray passing through the center.

[0008] In one possible technical solution, further, within the same or different Fresnel rings, the direction of the continuous winding adopts a combination of clockwise and counterclockwise winding to form a reciprocating winding structure; wherein, the segmented spiral electrodes wound clockwise and the segmented spiral electrodes wound counterclockwise are mirror images of each other about an axis passing through the same center.

[0009] In one possible technical solution, the segmented spiral electrode can rotate around the center within different Fresnel rings, thereby forming a spatially discontinuous staggered layout.

[0010] In one possible technical solution, the segmented spiral electrodes in the same Fresnel ring are further arranged in a circumferential array.

[0011] In one possible technical solution, the segmented spiral electrode within each Fresnel ring is further divided into multiple electrode segments, and the multiple electrode segments maintain continuous electrical connection.

[0012] In one possible technical solution, the spiral electrode is further described as having a spiral trajectory, an Archimedean spiral, or a Fermat spiral.

[0013] In one possible technical solution, when the spiral trajectory of the spiral electrode is helical, its trajectory is defined by the following equation: , in, , In the formula, This represents the polar angle corresponding to any point on the helix, that is, the angle between the line connecting that point and the center of the circle and the positive x-axis. It is the angle at which the line connecting any point on the helix and the center of the circle intersects the positive x-axis. r represents the radius, and a is a constant coefficient. It is a constant.

[0014] A Fresnel liquid crystal lens includes a first substrate and a second substrate disposed opposite to each other, and a first electrode, a second electrode, and a liquid crystal layer located between the first substrate and the second substrate, wherein... The first electrode is a planar electrode, and the second electrode is the Fresnel patterned electrode described above. A preset voltage is applied to the first electrode and the second electrode to deflect the liquid crystal and form a Fresnel liquid crystal lens.

[0015] The Fresnel patterned electrode based on a segmented spiral according to the present invention has the following advantages: 1. By incorporating segmented spiral electrodes within the Fresnel ring and combining them with a concentric circular electrode structure, the continuous voltage distribution along the length of the spiral electrodes can be extended to the entire lens aperture region, thereby forming a near-continuous parabolic phase distribution in the liquid crystal layer. Compared to traditional discrete electrode structures, this effectively improves the phase control accuracy of the liquid crystal lens, thereby enhancing the lens's focusing performance and imaging clarity. Furthermore, the increased design freedom of the concentric circular electrode width allows for further optimization of the Fresnel band structure, reducing the impact of diffraction effects on optical performance.

[0016] 2. By segmenting the spiral electrodes according to Fresnel loops, a corresponding continuous voltage distribution can be formed within each Fresnel loop, thereby achieving a near-ideal parabolic phase distribution across the entire lens aperture. This structure ensures phase modulation consistency between different Fresnel loops and facilitates continuous phase modulation of large-aperture liquid crystal lenses. Simultaneously, the segmented spiral structure reduces the patterning complexity of large-size continuous spiral electrodes, improves device manufacturing yield, and maintains the advantage of thinner and lighter liquid crystal lenses.

[0017] 3. The patterned electrode structure of the present invention does not require additional driving circuit complexity. Continuous phase distribution can be achieved solely through the structural design of the electrode itself, without increasing the overall thickness of the liquid crystal lens. This maintains the structural advantages of a thin and light liquid crystal lens, making it suitable for applications with strict requirements on device thickness, such as portable displays and AR / VR optical modules.

[0018] Additional aspects and advantages of the invention will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention. Attached Figure Description

[0019] To more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0020] Figure 1 This is a schematic diagram of a Fresnel patterned electrode structure based on a segmented spiral according to an embodiment of the present invention. Figure 2 This is a schematic diagram of a spiral electrode being divided into multiple segmented spiral electrodes at the junction of adjacent Fresnel rings in an embodiment of the present invention; Figure 3 This is a schematic diagram of a spiral electrode with different parameters set in different Fresnel rings according to an embodiment of the present invention; Figure 4 This is a schematic diagram of the segmented spiral electrodes arranged in a circular ray within the Fresnel ring according to an embodiment of the present invention; Figure 5 This is a schematic diagram of the segmented spiral electrode rotating and moving in a circumferential direction within the Fresnel ring according to an embodiment of the present invention; Figure 6 This is a schematic diagram of the reciprocating spiral structure of the segmented spiral electrode in each Fresnel ring according to an embodiment of the present invention; Figure 7 This is a schematic diagram of the segmented spiral electrodes arranged in a circumferential array within the Fresnel ring according to an embodiment of the present invention; Figure 8 This is a schematic diagram of the helical curves of the segmented helical electrode under different values ​​of a according to an embodiment of the present invention; Figure 9 This is a schematic diagram of a Fresnel liquid crystal lens structure according to an embodiment of the present invention.

[0021] Figure label: First substrate 1, second substrate 2, first electrode 3, second electrode 4, concentric circle electrode 41, segmented spiral electrode 42, liquid crystal layer 5. Detailed Implementation

[0022] The embodiments of the present invention are described in detail below. The embodiments described with reference to the accompanying drawings are exemplary. It should be understood that the specific embodiments described herein are merely illustrative of this application and are not intended to limit this application.

[0023] It should be noted that when a component is said to be "fixed to" another component, it can be directly attached to the other component or there may be an intervening component. When a component is said to be "connected to" another component, it can be directly connected to the other component or there may be an intervening component.

[0024] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. The terminology used herein in the description of the invention is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. The term "and / or" as used herein includes any and all combinations of one or more of the associated listed items.

[0025] The terms "first," "second," "third," etc., in the specification, claims, and accompanying drawings of this application are used to distinguish different objects and not to describe a particular order. Furthermore, the terms "comprising" and "having," and any variations thereof, are intended to cover non-exclusive inclusion. For example, it may include a series of steps or units, or optionally, steps or units not listed, or other steps or units inherent to these processes, methods, products, or devices.

[0026] The accompanying drawings show only the portions relevant to this application, not all of them. Before discussing exemplary embodiments in more detail, it should be noted that some exemplary embodiments are described as processes or methods depicted as flowcharts. Although the flowcharts describe operations (or steps) as sequential processes, many of these operations may be performed in parallel, concurrently, or simultaneously. Furthermore, the order of the operations may be rearranged. The process may be terminated when its operation is completed, but may also have additional steps not included in the drawings. The process may correspond to a method, function, procedure, subroutine, subprogram, etc.

[0027] The terms “component,” “module,” “system,” “unit,” etc., used in this specification are used to refer to computer-related entities, hardware, firmware, combinations of hardware and software, software, or software in execution. For example, a unit can be, but is not limited to, a process running on a processor, a processor, an object, an executable file, a thread of execution, a program, and / or distributed between two or more computers. Furthermore, these units can be executed from various computer-readable media on which various data structures are stored. Units can communicate, for example, via local and / or remote processes based on signals having one or more data packets (e.g., data from a second unit interacting with another unit between a local system, a distributed system, and / or a network; for example, the Internet interacting with other systems via signals).

[0028] Example 1 This embodiment provides a Fresnel patterned electrode based on a segmented spiral, wherein it includes multiple Fresnel rings, such as... Figures 1 to 7 As shown, where Figures 1 to 7The dashed lines in the figure represent the boundaries of the Fresnel rings. Each Fresnel ring includes at least one concentric circular electrode 41, and each concentric circular electrode 41 in all Fresnel rings has the same center. It also includes a spiral electrode that extends continuously from the inside out, which is cut at the junction of adjacent Fresnel rings to form multiple segmented spiral electrodes 42, such as... Figure 2 As shown; Within the same Fresnel ring, the concentric circular electrode 41 is electrically connected to the segmented spiral electrode 42 to extend the voltage distribution formed on the segmented spiral electrode 42 in the circumferential direction of the Fresnel ring, so that the voltage distribution can cover the entire Fresnel ring.

[0029] It should be noted that, in this embodiment, the concentric electrode 41 is made of a transparent conductive material, such as indium tin oxide (ITO), to ensure that the liquid crystal lens has high optical transmittance. The spiral electrode can be made of ITO or other conductive materials.

[0030] It should be noted that, in this embodiment, the segmented spiral electrode 42 can be designed using different mathematical parameters within different Fresnel loops, such as... Figure 3 As shown, the different mathematical parameters include the rotation period, initial phase, and pitch of the spiral electrode. The electrode shape can be adjusted individually for the expected voltage distribution characteristics of each Fresnel ring, thereby more accurately matching the radial voltage gradient distribution required by the lens, effectively reducing the equivalent refractive index distribution deviation in the liquid crystal layer, improving the optical imaging quality of the liquid crystal lens, and retaining the advantages of low impedance and good voltage distribution linearity of the segmented spiral electrode itself. Performance improvement can be achieved without significantly increasing the complexity of the fabrication process.

[0031] It should be noted that, in this embodiment, the segmented spiral electrode 42 can perform a mirroring operation based on a ray passing through the center, such as... Figure 4 As shown. This design improves the overall symmetry of the electrode structure and reduces aberrations caused by phase asymmetry, thus improving the imaging quality of the liquid crystal lens. Furthermore, it facilitates applying the same driving voltage to the corresponding segmented spiral electrodes, simplifying the driving connection method and driving circuit design.

[0032] It should be noted that, in this embodiment, the segmented spiral electrodes 42 can all rotate at any angle, thereby forming a spatially discontinuous staggered layout, such as... Figure 5As shown, this design can improve the overall symmetry of the electrode structure and reduce aberrations caused by phase asymmetry, thereby improving the imaging quality of the liquid crystal lens. On the other hand, it can facilitate the application of the same driving voltage to the segmented spiral electrodes corresponding to the mirror image, thereby simplifying the driving connection method and driving circuit design.

[0033] It should be noted that, in this embodiment, within the same or different Fresnel rings, the continuous winding direction adopts a combination of clockwise and counterclockwise winding to form a reciprocating winding structure, such as... Figure 6 As shown; wherein, the segmented spiral electrode 42 wound clockwise and the segmented spiral electrode 42 wound counterclockwise are mirror images of each other about an axis passing through the same center.

[0034] The width, spacing, and distribution density of concentric circular electrodes within the same or different Fresnel zones can be set to be the same or different to adapt to different design requirements, thereby adjusting the discrete characteristics of the voltage within the lens aperture range without affecting the formation of the overall voltage distribution.

[0035] It should be noted that, in this embodiment, the segmented spiral electrodes 42 within the same Fresnel ring are arranged in a circumferential array, such as... Figure 7 As shown, using an array-based arrangement can improve the stability of the voltage distribution along the circumference and reduce the voltage attenuation along the circumference caused by the capacitance effect, thereby avoiding the phase distortion problem caused by uneven voltage distribution, which is beneficial to improving the phase control accuracy and overall optical performance of the liquid crystal lens.

[0036] It should be noted that, in this embodiment, the segmented spiral electrode 42 within each Fresnel ring is divided into multiple electrode segments, which are continuously electrically connected. Each electrode segment can be designed and adjusted individually, allowing for more flexible changes in the local potential distribution. Without disrupting the overall Fresnel phase distribution, this effectively counteracts the phase distortion caused by the edge electric field effect of the liquid crystal lens. At the same time, it further reduces the overall fabrication difficulty of the spiral electrode. When local errors occur during processing, only the corresponding small electrode segment needs to be corrected, thus improving the fabrication yield and balancing the flexibility of electrical performance control with the feasibility of production and processing.

[0037] It should be noted that, in this embodiment, the spiral electrode's winding trajectory can be any one of a spiral, an Archimedean spiral, or a Fermat spiral. The appropriate spiral trajectory can be selected according to the actual focusing requirements and processing conditions of the liquid crystal lens to ensure the matching degree of Fresnel phase distribution under different application scenarios, while meeting the design requirements of liquid crystal lenses with different apertures and focal lengths.

[0038] It should be noted that, in this embodiment, when the spiral electrode's winding trajectory is a helical shape, its trajectory is defined by the following equation: , in, , In the formula, This represents the polar angle corresponding to any point on the helix, that is, the angle between the line connecting that point and the center of the circle and the positive x-axis. It is the angle at which the line connecting any point on the helix and the center of the circle intersects the positive x-axis. r represents the radius, and a is a constant coefficient. It is a constant. For example... Figure 8 As shown, by adjusting the value of the constant coefficient 'a', segmented spiral electrodes with different curve shapes can be obtained.

[0039] like Figure 9 As shown, this embodiment provides a Fresnel liquid crystal lens, including a first substrate 1 and a second substrate 2 disposed opposite to each other, and a first electrode 3, a second electrode 4, and a liquid crystal layer 5 located between the first substrate 1 and the second substrate 2, wherein... The first electrode 3 is a planar electrode, and the second electrode 4 is the aforementioned Fresnel patterned electrode. A liquid crystal layer 5 is filled between the first substrate 1 and the second substrate 2 to form a liquid crystal cell. The liquid crystal alignment layer disposed on the electrode surface and the spacers used to control the thickness of the liquid crystal layer are not shown in the figure. In this embodiment, the Fresnel patterned electrode on the second substrate 2 is used to generate the desired spatial voltage distribution to regulate the orientation of the liquid crystal molecules and form the required phase distribution in the liquid crystal layer. The first electrode 3 on the first substrate 1 serves as a voltage reference electrode and is typically grounded. Applying a preset voltage to the first electrode 3 and the second electrode 4 causes the liquid crystal to deflect and form a Fresnel liquid crystal lens. This can create a spatially varying electric field distribution within the liquid crystal layer 5, thereby controlling the orientation of the liquid crystal molecules and realizing the optical modulation function of the liquid crystal lens.

[0040] The Fresnel patterned electrode based on a segmented spiral according to the present invention has the following advantages: 1. By incorporating segmented spiral electrodes within the Fresnel ring and combining them with a concentric circular electrode structure, the continuous voltage distribution along the length of the spiral electrodes can be extended to the entire lens aperture region, thereby forming a near-continuous parabolic phase distribution in the liquid crystal layer. Compared to traditional discrete electrode structures, this effectively improves the phase control accuracy of the liquid crystal lens, thereby enhancing the lens's focusing performance and imaging clarity. Furthermore, the increased design freedom of the concentric circular electrode width allows for further optimization of the Fresnel band structure, reducing the impact of diffraction effects on optical performance.

[0041] 2. By segmenting the spiral electrodes according to Fresnel loops, a corresponding continuous voltage distribution can be formed within each Fresnel loop, thereby achieving a near-ideal parabolic phase distribution across the entire lens aperture. This structure ensures phase modulation consistency between different Fresnel loops and facilitates continuous phase modulation of large-aperture liquid crystal lenses. Simultaneously, the segmented spiral structure reduces the patterning complexity of large-size continuous spiral electrodes, improves device manufacturing yield, and maintains the advantage of thinner and lighter liquid crystal lenses.

[0042] 3. The patterned electrode structure of the present invention does not require additional driving circuit complexity. Continuous phase distribution can be achieved solely through the structural design of the electrode itself, without increasing the overall thickness of the liquid crystal lens. This maintains the structural advantages of a thin and light liquid crystal lens, making it suitable for applications with strict requirements on device thickness, such as portable displays and AR / VR optical modules.

[0043] In the description of this invention, it should be understood that the terms "center," "longitudinal," "lateral," "length," "width," "thickness," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," "clockwise," "counterclockwise," "axial," "radial," and "circumferential" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on the invention.

[0044] In the description of this specification, references to terms such as "one embodiment," "some embodiments," "illustrative embodiment," "example," "specific example," or "some examples," etc., refer to specific features, structures, materials, or characteristics described in connection with that embodiment or example, which are included in at least one embodiment or example of the present invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example.

[0045] Obviously, the described embodiments are only a part of the embodiments of this application, and not all of the embodiments. The reference to "embodiment" herein means that a specific feature, structure, or characteristic described in connection with an embodiment can be included in at least one embodiment of this application. The appearance of this phrase in various places in the specification does not necessarily indicate the same embodiment, nor is it an independent or alternative embodiment mutually exclusive with other embodiments. It will be explicitly and implicitly understood by those skilled in the art that the embodiments described herein can be combined with other embodiments. All other embodiments obtained by those skilled in the art based on the embodiments of this application without inventive effort are within the scope of protection of this application.

[0046] Although embodiments of the invention have been shown and described, those skilled in the art will understand that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the claims and their equivalents.

Claims

1. A Fresnel patterned electrode based on a segmented spiral, characterized in that, It includes multiple Fresnel rings, each of which includes at least one concentric circular electrode (41), and each of the concentric circular electrodes (41) in all the Fresnel rings has the same center; It also includes a spiral electrode that extends continuously from the inside out, which is cut at the junction of adjacent Fresnel rings to form multiple segmented spiral electrodes (42). Within the same Fresnel ring, the concentric circular electrode (41) is electrically connected to the segmented spiral electrode (42) to extend the voltage formed on the segmented spiral electrode (42) in the circumferential direction of the Fresnel ring, so that the voltage distribution covers the entire Fresnel ring.

2. The Fresnel patterned electrode based on a segmented spiral according to claim 1, characterized in that, The segmented spiral electrodes (42) can all rotate circumferentially at any angle; or, Mirroring operations based on a ray passing through the center.

3. The Fresnel patterned electrode based on a segmented spiral according to claim 1, characterized in that, Within the same or different Fresnel rings, the direction of the continuous winding adopts a combination of clockwise and counterclockwise winding to form a reciprocating winding structure; wherein, the segmented spiral electrode (42) wound clockwise and the segmented spiral electrode (42) wound counterclockwise are mirror images of each other about an axis passing through the same center.

4. The Fresnel patterned electrode based on a segmented spiral according to claim 1, characterized in that, The width, spacing, and distribution density of concentric circular electrodes within different Fresnel rings can be set to be different.

5. The Fresnel patterned electrode based on a segmented spiral according to claim 1, characterized in that, The segmented spiral electrodes (42) in the same Fresnel ring are arranged in a circumferential array.

6. The Fresnel patterned electrode based on a segmented spiral according to claim 1, characterized in that, Each segmented spiral electrode (42) within the Fresnel ring is divided into multiple electrode segments, which are continuously electrically connected to each other.

7. The Fresnel patterned electrode based on a segmented spiral according to claim 1, characterized in that, The spiral electrode can be wound in any one of the following patterns: helical, Archimedean spiral, or Fermat spiral.

8. The Fresnel patterned electrode based on a segmented spiral according to claim 7, characterized in that, When the spiral trajectory of the spiral electrode is helical, its trajectory is defined by the following equation: ， in, ， In the formula, This represents the polar angle corresponding to any point on the helix, that is, the angle between the line connecting that point and the center of the circle and the positive x-axis. It also represents the angle at which the line connecting any point on the helix and the center of the circle intersects the positive x-axis. r represents the radius, and a is a constant coefficient. It is a constant.

9. The Fresnel patterned electrode based on a segmented spiral according to claim 8, characterized in that, Segmented spiral electrodes can be designed using different constant coefficients 'a' within different Fresnel rings.

10. A Fresnel liquid crystal lens, comprising a first substrate (1) and a second substrate (2) disposed opposite to each other, and a first electrode (3), a second electrode (4), and a liquid crystal layer (5) located on the surfaces of the first substrate (1) and the second substrate (2), characterized in that, The first electrode (3) is a planar electrode, and the second electrode (4) is a Fresnel patterned electrode as described in any one of claims 1 to 9. A preset voltage is applied to the first electrode (3) and the second electrode (4) to deflect the liquid crystal and form a Fresnel liquid crystal lens.

Images