Optical structure, optical system, and display device

Abstract

An optical structure, an optical system, and a display device. The optical structure comprises a first electrode layer, a second electrode layer, a liquid crystal layer, and a light shielding pattern. The first electrode layer comprises a plurality of annular electrodes, the second electrode layer is arranged opposite to the first electrode layer in a stacking direction, the liquid crystal layer is located between the first electrode layer and the second electrode layer, and the light shielding pattern is located on the side of at least one of the first electrode layer and the second electrode layer away from the liquid crystal layer. The first electrode layer is divided into a plurality of annular zones, and annular electrodes corresponding to the annular zones are configured to drive corresponding liquid crystal molecules in the liquid crystal layer to form Fresnel zones of an optical structure; and the plurality of annular electrodes include first annular electrodes located at edges of the annular zones, and in the stacking direction, the light shielding pattern at least partially overlaps at least one of the first annular electrodes. Therefore, stray light generated at a non-ideal phase jump position can be shielded by using the light shielding pattern, thereby improving user experience and the performance of the optical structure.

Description

Optical structures, optical systems and display devices

[0001] Cross-reference to related applications

[0002] This application claims priority to patent application No. PCT / CN2024 / 139609, filed on December 16, 2024, the disclosure of which is incorporated herein by reference in its entirety. Technical Field

[0003] At least one embodiment of this disclosure relates to an optical structure, an optical system, and a display device. Background Technology

[0004] Fresnel liquid crystal lenses are a new type of optical element that combines the microstructure of Fresnel lenses with the electronic control characteristics of liquid crystals. By applying different voltages to regulate the orientation of liquid crystal molecules, the refractive index can be dynamically changed, thereby achieving the functions of beam focusing, collimation, or zooming. Summary of the Invention

[0005] At least one embodiment of this disclosure provides an optical structure, an optical system, and a display device.

[0006] At least one embodiment of this disclosure provides an optical structure, including: a first electrode layer including a plurality of annular electrodes; a second electrode layer disposed opposite to the first electrode layer in a stacking direction; a liquid crystal layer located between the first electrode layer and the second electrode layer; and a light-shielding pattern located on a side of at least one of the first electrode layer and the second electrode layer away from the liquid crystal layer; wherein the first electrode layer is divided into a plurality of annular zones, and the annular electrode corresponding to each annular zone is configured to drive corresponding liquid crystal molecules in the liquid crystal layer to form a Fresnel zone region of the optical structure; the plurality of annular electrodes includes a first annular electrode located at the edge of each annular zone, and in the stacking direction, the light-shielding pattern overlaps at least partially with at least one of the first annular electrodes.

[0007] For example, according to at least one embodiment of the present disclosure, in the stacking direction, the centerline of the first annular electrode overlaps with the edge of the corresponding annular region.

[0008] For example, according to at least one embodiment of the present disclosure, the light-shielding pattern includes a plurality of light-shielding rings; in the stacking direction, the center line of the first annular electrode overlaps with the center line of the corresponding light-shielding ring.

[0009] For example, according to at least one embodiment of the present disclosure, the width of the light-shielding ring is smaller than the width of the corresponding first annular electrode; the width of the light-shielding ring is 1.5 micrometers to 6 micrometers, and the width of the first annular electrode is not less than 3.5 micrometers.

[0010] For example, according to at least one embodiment of the present disclosure, the plurality of ring electrodes further includes at least one second ring electrode located between two adjacent first ring electrodes.

[0011] For example, according to at least one embodiment of the present disclosure, the at least one second annular electrode is located in at least one annular region of the plurality of annular regions near the center of the annular electrode.

[0012] For example, according to at least one embodiment of the present disclosure, the spacing between two adjacent annular electrodes in the plurality of annular electrodes gradually decreases along the direction from the center of the annular electrode to the edge.

[0013] For example, according to at least one embodiment of the present disclosure, the width of the plurality of annular electrodes gradually decreases along the direction from the center of the annular electrode to the edge.

[0014] For example, according to at least one embodiment of the present disclosure, the light-shielding pattern includes a plurality of light-shielding rings in a direction from the center of the annular electrode to the edge, wherein the spacing between two adjacent light-shielding rings gradually decreases.

[0015] For example, according to at least one embodiment of the present disclosure, the light-shielding pattern includes a plurality of light-shielding rings, the width of which gradually decreases along the direction from the center of the annular electrode to the edge.

[0016] For example, according to at least one embodiment of the present disclosure, the optical structure further includes a high-resistivity layer, wherein the high-resistivity layer includes a high-resistivity portion located in the gap between two adjacent annular electrodes in the same layer and connected between the two adjacent annular electrodes.

[0017] For example, according to at least one embodiment of the present disclosure, the first electrode layer includes at least two sub-layers, and at least two of the plurality of annular electrodes are located in different sub-layers.

[0018] For example, according to at least one embodiment of this disclosure, the at least two sub-layers include a first sub-layer and a second sub-layer, the plurality of annular electrodes include a plurality of first sub-electrodes and a plurality of second sub-electrodes, the plurality of first sub-electrodes being located in the first sub-layer, and the plurality of second sub-electrodes being located in the second sub-layer; among the plurality of first sub-electrodes and the plurality of second sub-electrodes, the annular electrode located at the edge of each annular zone is the first annular electrode; in the stacking direction, the spacing between two adjacent second sub-electrodes of the first sub-electrodes and the plurality of second sub-electrodes overlaps.

[0019] For example, according to at least one embodiment of the present disclosure, in the stacking direction, the first sub-electrode overlaps with a portion of the second sub-electrode.

[0020] For example, according to at least one embodiment of the present disclosure, the optical structure further includes a first high-resistivity structure and a second high-resistivity structure; wherein the first high-resistivity structure is located in the interval between two adjacent first sub-electrodes of the plurality of first sub-electrodes and is connected between the two adjacent first sub-electrodes; the second high-resistivity structure is located in the interval between two adjacent second sub-electrodes of the plurality of second sub-electrodes and is connected between the two adjacent second sub-electrodes.

[0021] For example, according to at least one embodiment of the present disclosure, the second electrode layer is a common electrode; the second electrode layer includes a surface electrode, or; the second electrode layer includes an electrode pattern, wherein the electrode pattern overlaps with the electrode spacing between two adjacent annular electrodes in the stacking direction.

[0022] For example, according to at least one embodiment of the present disclosure, the optical structure further includes a spacer located between the first electrode layer and the second electrode layer; wherein the optical structure is configured to switch between positive and negative optical power; and in a plane perpendicular to the stacking direction, the orthogonal projection of the spacer overlaps with the orthogonal projection of the first annular electrode.

[0023] For example, according to at least one embodiment of the present disclosure, the optical structure further includes a spacer located between the first electrode layer and the second electrode layer; wherein the optical structure is configured to have positive optical power; and on a plane perpendicular to the stacking direction, the orthographic projection of the first annular electrode has a center line, and the orthographic projection of the spacer is located on the side of the center line away from the center of the annular region.

[0024] For example, according to at least one embodiment of the present disclosure, the optical structure further includes a spacer located between the first electrode layer and the second electrode layer; wherein the optical structure is configured to have negative optical power; and on a plane perpendicular to the stacking direction, the orthogonal projection of the first annular electrode has a center line, and the orthogonal projection of the spacer is located on the side of the center line near the center of the annular region.

[0025] At least one embodiment of this disclosure provides an optical system comprising the optical structure described in any of the above embodiments; at least two lenses; wherein the optical structure and the at least two lenses are arranged on the optical axis of the optical system; and the optical structure is located between two adjacent lenses of the at least two lenses.

[0026] At least one embodiment of this disclosure provides a display device including the optical system described above. Attached Figure Description

[0027] To more clearly illustrate the technical solutions of the embodiments of this disclosure, the accompanying drawings of the embodiments will be briefly described below. Obviously, the drawings described below only relate to some embodiments of this disclosure and are not intended to limit this disclosure.

[0028] Figure 1 is a cross-sectional schematic diagram of an optical structure provided in at least one embodiment of the present disclosure.

[0029] Figure 2 is a planar schematic diagram of the first electrode layer of an optical structure provided in at least one embodiment of the present disclosure.

[0030] Figure 3 is a standard curve showing the phase delay distribution of an optical structure provided in at least one embodiment of this disclosure.

[0031] Figure 4 is a plan view of a ring zone region in the first electrode layer of an optical structure provided in at least one embodiment of the present disclosure.

[0032] Figures 5A to 5E are schematic planar views of the annular electrode in the first electrode layer of the optical structure provided in different examples of at least one embodiment of this disclosure.

[0033] Figure 6A is a cross-sectional schematic diagram of an optical structure provided in at least one embodiment of the present disclosure.

[0034] Figure 6B is a partial planar schematic diagram of the first electrode layer and the high-resistivity layer in the optical structure shown in Figure 6A.

[0035] Figures 7 and 8 are schematic cross-sectional views of optical structures provided in at least one embodiment of this disclosure, representing different examples.

[0036] Figures 9A to 11B are partial schematic diagrams of optical structures provided in different examples of at least one embodiment of this disclosure.

[0037] Figure 12 is a partial structural schematic diagram of an optical structure provided in at least one embodiment of the present disclosure.

[0038] Figure 13 is a schematic diagram of an optical system provided in at least one embodiment of the present disclosure. Detailed Implementation

[0039] To make the objectives, technical solutions, and advantages of the embodiments of this disclosure clearer, the technical solutions of the embodiments of this disclosure will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of this disclosure. Based on the described embodiments of this disclosure, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this disclosure.

[0040] Unless otherwise defined, the technical or scientific terms used in this disclosure shall have the ordinary meaning understood by one of ordinary skill in the art to which this disclosure pertains. The terms “first,” “second,” and similar terms used in this disclosure do not indicate any order, quantity, or importance, but are merely used to distinguish different components. Terms such as “comprising” or “including” mean that an element or object preceding the word encompasses the elements or objects listed following the word and their equivalents, without excluding other elements or objects.

[0041] The terms "parallel," "perpendicular," and "identical" as used in this disclosure include the strictly defined meanings of "parallel," "perpendicular," and "identical," as well as terms such as "approximately parallel," "approximately perpendicular," and "approximately identical," which include a certain degree of error. Taking into account measurement and errors associated with the measurement of a specific quantity (i.e., limitations of the measurement system), they represent acceptable deviations for a specific value as determined by a person skilled in the art. In embodiments of this disclosure, "center" can include a strictly defined location at the geometric center as well as a location approximately at the center within a small area surrounding the geometric center. For example, "approximately" can mean within one or more standard deviations, or within 10% or 5% of the value.

[0042] In other examples, liquid lens technology utilizes the physical properties of liquids to achieve dynamic adjustment of the focal length. For instance, an electromagnetic coil can be used to compress the liquid, thereby changing the volume of the liquid inside the lens by using electromagnetic force to drive its flow, thus adjusting the optical power. In their research, the inventors of this application found that the process of the electromagnetic coil compressing the liquid is complex and difficult to control precisely. Inaccurate control can lead to problems such as blurred images and inaccurate depth-of-field positioning, and the stability and accuracy of focusing need to be improved.

[0043] At least one embodiment of this disclosure provides an optical structure including a first electrode layer, a second electrode layer, a liquid crystal layer, and a light-shielding pattern. The first electrode layer includes a plurality of annular electrodes, and the second electrode layer is disposed opposite to the first electrode layer in a stacking direction. The liquid crystal layer is located between the first electrode layer and the second electrode layer, and the light-shielding pattern is located on the side of at least one of the first electrode layer and the second electrode layer away from the liquid crystal layer. The first electrode layer is divided into a plurality of annular zones, and the annular electrode corresponding to each annular zone is configured to drive corresponding liquid crystal molecules in the liquid crystal layer to form a Fresnel zone region of the optical structure. The plurality of annular electrodes includes a first annular electrode located at the edge of each annular zone, and in the stacking direction, the light-shielding pattern overlaps at least partially with at least one of the first annular electrodes.

[0044] At least one embodiment of this disclosure provides an optical system including the aforementioned optical structure and at least two lenses. The optical structure and the at least two lenses are arranged on the optical axis of the optical system, with the optical structure located between two adjacent lenses.

[0045] At least one embodiment of this disclosure provides a display device including the optical system described above.

[0046] In the optical structure, optical system, and display device provided in at least one embodiment of this disclosure, the annular electrodes corresponding to each annular zone in the first electrode layer of the optical structure can work together with the second electrode layer to drive the liquid crystal molecules in the liquid crystal layer, thereby precisely controlling the light and realizing dynamic adjustment of the focal length of the optical structure. Furthermore, by forming Fresnel wave zones using the annular electrodes corresponding to the annular zones and setting a light-shielding pattern overlapping the first annular electrode on the edge of the annular zone, stray light generated at non-ideal phase transition positions can be blocked using the light-shielding pattern. Thus, an optical structure with a large aperture and high response speed can be formed using a thinner liquid crystal layer, and aberrations are reduced by decreasing stray light, allowing the image to remain clear and sharp, improving the user experience and the performance of the optical structure.

[0047] The optical structure, optical system, and display device are described below with reference to the accompanying drawings and through some embodiments.

[0048] Figure 1 is a cross-sectional schematic diagram of an optical structure provided in at least one embodiment of the present disclosure.

[0049] Referring to FIG1, at least one embodiment of this disclosure provides an optical structure including a first electrode layer 100, a second electrode layer 200, a liquid crystal layer 300, and a light-shielding pattern 400. The first electrode layer 100 includes a plurality of annular electrodes (e.g., annular electrode 110 shown in FIG1). The second electrode layer 200 is disposed opposite to the first electrode layer 100 in the stacking direction, and the liquid crystal layer 300 is located between the first electrode layer 100 and the second electrode layer 200. For example, the stacking direction can be the direction indicated by the Z-direction arrow shown in FIG1 or the direction opposite to the direction indicated by the arrow.

[0050] Referring to Figure 1, the light-shielding pattern 400 is located on the side of at least one of the first electrode layer 100 and the second electrode layer 200 away from the liquid crystal layer 300. For example, the light-shielding pattern 400 may be located only on the side of the first electrode layer 100 away from the liquid crystal layer 300. For example, the light-shielding pattern 400 may be located only on the side of the second electrode layer 200 away from the liquid crystal layer 300. For example, a portion of the light-shielding pattern 400 may be located on the side of the first electrode layer 100 away from the liquid crystal layer 300, and another portion of the light-shielding pattern 400 may be located on the side of the second electrode layer 200 away from the liquid crystal layer 300.

[0051] Referring to Figure 1, the first electrode layer 100 is divided into multiple annular zones FZ. The annular electrode corresponding to each annular zone FZ is configured to drive the corresponding liquid crystal molecules in the liquid crystal layer 300 to form the Fresnel zone region of the optical structure.

[0052] Referring to Figure 1, the plurality of annular electrodes include a first annular electrode 111 located at the edge of each annular zone FZ. For example, in the stacking direction, the orthographic projection of the first annular electrode 111 can cover the edge of the orthographic projection of the corresponding annular zone FZ.

[0053] Referring to FIG1, in the stacking direction, the light-shielding pattern 400 overlaps at least a portion of at least one first annular electrode 111. For example, in the stacking direction, the light-shielding pattern 400 may overlap only one first annular electrode 111. For example, in the stacking direction, the light-shielding pattern 400 may overlap with multiple first annular electrodes 111. For example, in the stacking direction, the light-shielding pattern 400 may overlap with all of the first annular electrodes 111. For example, in the stacking direction, the light-shielding pattern 400 may overlap only a portion of the first annular electrode 111 and not with another portion of the first annular electrode 111. For example, in the stacking direction, the light-shielding pattern 400 may overlap with all of the first annular electrodes 111.

[0054] In the optical structure provided in this embodiment, referring to FIG1, the annular electrodes corresponding to each annular zone FZ in the first electrode layer 100 can work together with the second electrode layer 200 to drive the liquid crystal molecules in the liquid crystal layer 300 to precisely control the light and achieve dynamic adjustment of the focal length of the optical structure. Furthermore, by using the annular electrodes corresponding to the annular zones FZ to form Fresnel wave zones, and by setting a light-shielding pattern 400 overlapping with the first annular electrode 111 on the edge of the annular zone FZ, stray light generated at non-ideal phase transition positions can be blocked using the light-shielding pattern 400. Thus, an optical structure with a large aperture and high response speed can be formed using a thinner liquid crystal layer 300, and aberrations are reduced by decreasing stray light, allowing the image to remain clear and sharp, improving the user experience and the performance of the optical structure.

[0055] For example, under the influence of an electric field, an optical structure can form a liquid crystal Fresnel lens, equivalent to a Fresnel lens. The Fresnel zone region can be equated to the Fresnel teeth in a Fresnel lens, also known as Fresnel side lobes. To facilitate understanding of the Fresnel zone region, a simple explanation of Fresnel teeth is provided. A Fresnel lens, also known as a threaded lens, divides the curved surface of a refracting lens into a series of tiny tooth-like structures (i.e., Fresnel teeth). The texture formed by these tooth-like structures is roughly composed of a series of concentric circles. Through phase distribution, these tooth-like structures can create a specific optical path difference in light, altering the degree of refraction. For example, a parabolic phase retardation distribution can be formed using geometric thickness differences, causing light to converge or be adjusted into parallel light.

[0056] In designing the Fresnel zone region of the optical structure, the inventors of this application noted that the discrete phase approximation of multiple ring electrodes and the phase jump at the edge of the Fresnel zone are important factors causing high-frequency wavefront noise and diffraction stray light, directly affecting the aberrations of the optical structure. Specifically, the optical structure uses multiple ring electrodes to make the phase retardation approach a continuous phase distribution. However, since the multiple ring electrodes have a discrete structure, this leads to abrupt changes in the electric field, causing a discontinuous distribution of the phase retardation. Consequently, the discrete phase distribution introduces high-frequency wavefront noise, and the phase jump at the edge of the Fresnel zone introduces diffraction stray light, which affects the root mean square (RMS) value of the image. It is understood that the RMS value is one of the indicators for evaluating image quality; the smaller the RMS value, the clearer the image, i.e., the higher the image quality. However, diffraction stray light causes an increase in the RMS value.

[0057] By using a light-shielding pattern to block the edges of each Fresnel zone, stray light from non-designed directions can be intercepted and absorbed, suppressing optical crosstalk and improving imaging contrast and overall image quality. For example, the optical structure provided in at least one embodiment of this disclosure can reduce edge diffraction loss by more than 30%, and the RMS value can be reduced to 0.06 to 0.13 times the reference wavelength, which can be the wavelength of the green light band.

[0058] Furthermore, compared to methods that rely on the movement or replacement of physical structures to adjust the focal length, the optical structure in this embodiment does not require mechanical adjustments; the focal length can be flexibly controlled using voltage variations. This not only simplifies the complexity of the optical system and improves response speed and adjustment accuracy, but also reduces energy consumption and maintenance costs.

[0059] It should be noted that Figure 1 only schematically shows the liquid crystal layer, and the phase retardation distribution curve under the action of an electric field is schematically shown by dashed lines. The liquid crystal molecules in the liquid crystal layer are omitted in Figure 1.

[0060] For example, the ring electrode has a shape that is close to a ring. For example, the orthographic projection of the ring electrode onto a plane perpendicular to the stacking direction can be a closed shape or a non-closed shape, for example, it can have a gap. For example, in the case where the ring electrode is a non-closed shape, the light-shielding pattern can block the gap of the non-closed shape.

[0061] For example, the aforementioned closed-shaped ring can include circular rings, elliptical rings, square rings, polygonal rings (e.g., regular hexagonal rings), etc. In the embodiments of this disclosure, a circular ring is used as an example for illustrative purposes, and will not be described again hereafter.

[0062] For example, multiple ring electrodes can be arranged concentrically. For example, in the case where the ring electrodes are circular ring electrodes, the centers of the multiple ring electrodes coincide with each other.

[0063] For example, the material of the ring electrode may include indium tin oxide (ITO).

[0064] For example, a Fresnel zone region consists of a central circular region and multiple annular regions concentrically arranged around it. Each circular region and each annular region constitutes a Fresnel zone region. For instance, the annular electrodes corresponding to each annular zone region interact with the second electrode layer to generate an electric field that drives the liquid crystal molecules, thus forming the Fresnel zone region.

[0065] For example, Figure 1 only schematically shows that the first electrode layer includes a first annular electrode, but this disclosure is not limited to this. For example, in the examples described later, the first electrode layer may also include a second annular electrode, which will not be elaborated here. For example, the annular electrode corresponding to each annular zone includes a first annular electrode located on the edge of the annular zone. In the case where other annular electrodes are included in the annular zone, the annular electrode corresponding to the annular zone also includes the other annular electrodes mentioned above (e.g., the second annular electrode in the examples described later).

[0066] Controlling light using liquid crystal molecules within a liquid crystal layer is an innovative display technology. This technology, through special design of the liquid crystal layer and electrode layers, enables precise control of light. This technology not only achieves more delicate and realistic image effects on display devices but also has wide applications in various devices requiring light control, such as industrial lenses. For example, when no electric field is generated between the first and second electrode layers, the liquid crystal molecules in the liquid crystal layer align along the alignment direction. When a voltage is applied, due to the polarity of the liquid crystal molecules, they deflect along the direction of the electric field, causing a change in the refractive index of the extraordinary light (e-ray).

[0067] Liquid crystal molecules undergo directional alignment changes under the influence of an electric field, thereby enabling the optical structure to function as a lens and effectively alter the refractive index of light. By achieving a specific refractive index distribution curve, a specific focal length can be achieved. Therefore, the focal length adjustable range of the optical structure provided in this disclosure embodiment is relatively large. For example, the optical structure can possess positive or negative optical power, and the adjustment range of optical power can be three diopters (D).

[0068] The wide adjustment range makes this optical structure suitable for various scenarios, from close-range microscopic observation to long-range macroscopic monitoring. For example, it can be applied in augmented reality (AR) displays, adaptive optics systems, and photography and videography. In consumer electronics such as smartphones, tablets, and wearable devices, it provides users with a superior visual experience, whether capturing the intricate textures of a macro world or the details of a magnificent landscape from afar. In machine vision, it enables rapid focusing and zooming of objects at different distances, improving detection accuracy and efficiency. In automated inspection, it allows for real-time inspection and monitoring of products on production lines, enhancing product quality and production efficiency. Finally, it can be used in optical equipment such as microscopes, telescopes, and projectors to meet the needs of different fields.

[0069] For example, the material of the liquid crystal layer can include a high-refractive-index liquid crystal material, such as a liquid crystal with an extraordinary refractive index and an ordinary refractive index difference Δn of 0.293. For example, in cases where high image sharpness is required, the thickness of the liquid crystal layer can be designed to be less than 10 micrometers. For example, in cases where high optical power is required, the thickness of the liquid crystal layer can be designed to be greater than 10 micrometers.

[0070] The optical structure provided in this disclosure has broad-spectrum transmission characteristics, meaning it can maintain high transmittance over a wide wavelength range of 400 nm to 700 nm. Therefore, this optical structure can effectively focus and image light of different wavelengths.

[0071] Referring to Figure 1, the optical structure may further include, for example, a first substrate 10 and a second substrate 20. The first substrate 10 is located on the side of the first electrode layer 100 away from the liquid crystal layer 300, and the second substrate 20 is located on the side of the second electrode layer 200 away from the liquid crystal layer 300. For example, the optical structure may further include two alignment layers, located on the side of the first electrode layer 100 near the liquid crystal layer 300 and the side of the second electrode layer 200 near the liquid crystal layer 300, respectively. By providing alignment layers, the alignment direction of the liquid crystal molecules in the liquid crystal layer 300 can be guided to ensure that the liquid crystal molecules can be neatly aligned when energized, thereby improving the display effect. The two alignment layers employ a reverse parallel friction process to facilitate improved symmetry of light distribution.

[0072] For example, the materials for the orientation layer may include polyimide (PI) and polymethyl methacrylate (PMMA).

[0073] Figure 2 is a planar schematic diagram of the first electrode layer of an optical structure provided in at least one embodiment of the present disclosure.

[0074] It should be noted that Figure 2 only schematically shows that the first electrode layer includes a first annular electrode, but this disclosure is not limited to this. For example, in the examples described later, the first electrode layer may also include a second annular electrode, which will not be discussed here. In addition, Figure 2 schematically shows the center lines of each first annular electrode with dashed lines.

[0075] Referring to Figures 1 and 2, in some examples, the centerline of the first annular electrode overlaps with the edge of the corresponding annular region in the stacking direction. The electric field generated at the center of the first annular electrode is predominantly a vertical electric field, and it is relatively less affected by the transverse electric field. This simplifies the design of the annular region and facilitates precise control of the light direction by the optical structure.

[0076] For example, the center lines of two adjacent first annular electrodes define an annular zone. For example, the center line of the first annular electrode passes through half the width of the first annular electrode. For example, the perpendicular distance between the center line of the first annular electrode and its inner edge is substantially equal everywhere, the perpendicular distance between the center line of the first annular electrode and its outer edge is substantially equal everywhere, and the perpendicular distances between the center line of the first annular electrode and its inner edge and its outer edge are substantially equal.

[0077] Referring to Figures 1 and 2, for example, the first electrode layer 100 may further include a central electrode 113, and an annular electrode may surround the central electrode 113. For example, the center of the central electrode 113 coincides with the center of the annular electrode. For example, the outer contour shape of the central electrode may be the same as the inner contour shape of the annular electrode. For example, when the annular electrode is annular, the central electrode may be circular, in which case the center of the central electrode may coincide with the center of the annular electrode.

[0078] For example, in this embodiment of the disclosure, the “center” of a structure can be the geometric center of the structure, which will not be elaborated further below.

[0079] According to Fermat's theorem, when the Fresnel refractive index surface of the liquid crystal satisfies a parabolic structure, the radius of the central electrode satisfies R1. 2 =f×2×(n) eff -n0)×d, where n eff Let n be the unusual refractive index of the liquid crystal, n0 be the ordinary refractive index of the liquid crystal, d be the thickness of the liquid crystal layer, and f be the focal length of the optical structure. The inner contour radius of the annular region satisfies Rn 2 =n×R1 2 In this situation, light rays passing through the optical structure can converge to a single point, spherical aberration can be minimized, and aberrations can be reduced.

[0080] As shown in the above formula, the imaging effect of the optical structure can be improved by designing the radius of the inner contour of each annular zone. Furthermore, by designing the centerline of the first annular electrode to overlap with the edge of the annular zone, fine-tuning of the light can be achieved, thus improving image quality.

[0081] For example, in designing a Fresnel refractive index surface for liquid crystals, aspherical design can be used to optimize the surface shape, improve dispersion, and thus minimize various aberrations. Aspherical surfaces come in many shapes, such as parabolic, hyperboloid, elliptical, and freeform surfaces, and their shape is determined by a series of high-order polynomials. Through aspherical design, the surface of the equivalent Fresnel lens can be made to better conform to the laws of light propagation, thereby reducing aberrations.

[0082] For example, the surface shape of an aspherical surface can be represented by the following numerical formula:

[0083] For example, in the above formula, the height of the aspherical surface along the direction perpendicular to the optical axis is h, and the distance from the vertex of the aspherical surface to the projection of the point at height h on the aspherical surface onto the optical axis is z(h). That is, z(h) is the coordinate along the optical axis; C is the curvature (the reciprocal of the radius of curvature R), k is the conic constant, and A... 2iThese are the coefficients of the higher-order terms, and 2i represents the higher power of the aspherical coefficient.

[0084] Figure 3 is a standard curve showing the phase delay distribution of an optical structure provided in at least one embodiment of this disclosure.

[0085] The horizontal axis of Figure 3 represents the radial dimension, such as the radius of the Fresnel zone, in micrometers. The vertical axis of Figure 3 represents the phase delay, in nanometers.

[0086] Referring to Figure 3, for example, the value of k can be -1. For example, the product of Δn and the thickness d of the liquid crystal layer can be equivalent to z(h). Based on an optimized fit with Δn of 0.293 and d of 6 micrometers, A4 can be obtained as -5 × 10⁻⁵. -6 to -5.25×10 -5 A6 is 0 to -8.75 × 10 -5 Therefore, while ensuring the Fresnel refractive index surface satisfies a parabolic structure, the key optical performance indicator, the RMS value, can be less than 0.5 times the reference wavelength. Referring to the example described later, the width of the ring electrode can be designed, such as by gradually decreasing the width from the center to the edge, to improve the continuity of the electric field's control over liquid crystal molecules, thereby reducing the RMS value by 0.05 to 0.08 times the reference wavelength. Furthermore, by adjusting the voltage drive scheme and suppressing assembly errors, the RMS value can be reduced by 0.03 to 0.05 times the reference wavelength. Combining this with the relevant content of the optical system described later, by designing the matching between lenses in the optical system, the RMS value can be optimized to less than 0.4 times the reference wavelength.

[0087] Referring to Figure 1, in some examples, the light-shielding pattern 400 includes multiple light-shielding rings 410. In the stacking direction, the centerline of the first annular electrode 110 overlaps with the centerline of the corresponding light-shielding ring 410. Figure 1 schematically shows the overlap of the centerline of the first annular electrode 110 and the centerline of the corresponding light-shielding ring 410 with a dashed line extending along the Z direction. Thus, when the first annular electrode 111 generates a near-vertical electric field, the light-shielding ring 410 can effectively and precisely block the dark area generated at the boundary of two adjacent annular zones FZ (i.e., the edge of the annular zone FZ). For example, in conjunction with the structure of a Fresnel lens, the aforementioned dark area can correspond to the region corresponding to the tip of a Fresnel tooth. Furthermore, while blocking stray light and suppressing optical crosstalk, the width of the light-shielding ring 410 can be designed to be narrower to improve light extraction efficiency.

[0088] For example, a light-blocking pattern may include a black matrix (BM).

[0089] For example, multiple light-shielding rings can be set concentrically.

[0090] Referring to Figure 1, in some examples, the width of the light-shielding ring 410 is smaller than the width of the corresponding first annular electrode 111. For example, in the stacking direction, the light-shielding ring 410 may overlap with its corresponding first annular electrode 111. The width of the light-shielding ring 410 is 1.5 micrometers to 7.5 micrometers, and the width of the first annular electrode 111 is 3.5 micrometers to 50 micrometers. The direction of the electric field generated by the first annular electrode 111 may have a certain slope, for example, it is not strictly perpendicular to the main surface of the first electrode layer 100. In this case, the apex of the equivalent Fresnel tooth formed by the liquid crystal molecules may not be strictly aligned with the centerline of the first annular electrode 111. By designing the width of the light-shielding ring 410, it is possible to make the light-shielding ring 410 block the apex of the equivalent Fresnel tooth, thereby improving the blocking effect on dark areas, improving the contrast of the image and the overall image quality.

[0091] Understandably, if the width of the ring electrode (such as the first ring electrode) is less than 3.5 micrometers, it may lead to poor ring electrode formation. If the width of the ring electrode is too large, such as greater than 50 micrometers, it will be difficult to achieve precise control of the light. If the width of the light-shielding ring is too small, such as less than 1.5 micrometers, it will increase the difficulty of alignment with the first ring electrode, and considering the non-perpendicular electric field, an excessively narrow light-shielding ring may not be able to guarantee the blocking of the equivalent Fresnel tooth tip, making it difficult to achieve a good blocking effect for stray light. Moreover, the manufacturing cost may be high. If the width of the light-shielding ring is too large, such as greater than 7.5 micrometers, it may block ideal light other than stray light, reducing the light extraction efficiency.

[0092] For example, the width of a ring electrode refers to the distance between the inner and outer edges of the ring electrode in the direction from the center of the ring electrode to the edge.

[0093] For example, the width of a light-shielding ring refers to the distance between the inner and outer edges of the light-shielding ring in the direction from the center of the ring to the edge.

[0094] For example, on a plane perpendicular to the stacking direction, the orthographic projection of the light-shielding ring can lie entirely within the orthographic projection of the ring electrode.

[0095] For example, the width of the ring electrode can be from 3.5 micrometers to 50 micrometers. For example, the width of the ring electrode closer to the central electrode can be relatively large, such as reaching 50 micrometers. For example, the width of the ring electrode farther from the central electrode can be relatively narrow. To achieve precise electric field control, the width of the ring electrode farther from the central electrode can be 3.5 micrometers, 3.6 micrometers, 3.7 micrometers, 3.8 micrometers, 3.9 micrometers, 4 micrometers, 4.1 micrometers, 4.2 micrometers, 4.3 micrometers, 4.4 micrometers, 4.5 micrometers, etc., and this disclosure does not limit this. For example, the width of the ring electrode can be from 5 micrometers to 50 micrometers. For example, the width of the ring electrode can be from 10 micrometers to 45 micrometers. For example, the width of the ring electrode can be from 15 micrometers to 40 micrometers. For example, the width of the ring electrode can be from 20 micrometers to 35 micrometers. For example, the width of the ring electrode can be from 25 micrometers to 30 micrometers. Of course, this disclosure is not limited to these values; the width of the ring electrode can also be other values ​​within the above ranges, which will not be listed here.

[0096] For example, the width of the light-shielding ring can be from 1.5 micrometers to 7.5 micrometers. For example, the width of the light-shielding ring can be from 1.5 micrometers to 7 micrometers. For example, the width of the light-shielding ring can be from 1.5 micrometers to 6.5 micrometers. For example, the width of the light-shielding ring can be from 1.5 micrometers to 6 micrometers. For example, the width of the light-shielding ring can be from 1.6 micrometers to 5.5 micrometers. For example, the width of the light-shielding ring can be from 1.7 micrometers to 5 micrometers. For example, the width of the light-shielding ring can be from 1.8 micrometers to 4.5 micrometers. For example, the width of the light-shielding ring can be from 1.9 micrometers to 4.4 micrometers. For example, the width of the light-shielding ring can be from 2 micrometers to 4.3 micrometers. For example, the width of the light-shielding ring can be from 2.1 micrometers to 4.2 micrometers. For example, the width of the light-shielding ring can be from 2.2 micrometers to 4.1 micrometers. For example, the width of the light-shielding ring can be from 2.3 micrometers to 4 micrometers. For example, the width of the light-shielding ring can be from 2.4 micrometers to 3.9 micrometers. For example, the width of the light-shielding ring can be from 2.5 micrometers to 3.8 micrometers. For example, the width of the light-shielding ring can be from 2.6 micrometers to 3.7 micrometers. For example, the width of the light-shielding ring can be from 2.7 micrometers to 3.6 micrometers. For example, the width of the light-shielding ring can be from 2.8 micrometers to 3.5 micrometers. For example, the width of the light-shielding ring can be from 2.9 micrometers to 3.4 micrometers. For example, the width of the light-shielding ring can be from 3.0 micrometers to 3.3 micrometers. For example, the width of the light-shielding ring can be from 3.1 micrometers to 3.2 micrometers. Of course, this disclosure is not limited to these values; the width of the light-shielding ring can also be other values ​​within the above ranges, which will not be listed here.

[0097] Figure 4 is a plan view of a ring zone region in the first electrode layer of an optical structure provided in at least one embodiment of the present disclosure.

[0098] Referring to Figure 4, in some examples, the plurality of annular electrodes further includes at least one second annular electrode 112, which is located between two adjacent first annular electrodes 111. This allows for more precise control of the liquid crystal molecules. For example, different voltages can be applied to different annular electrodes within the same annular region in a direction from the center to the edge, causing the liquid crystal molecules to change accordingly under the influence of the electric field.

[0099] It should be noted that Figure 4 schematically shows the inner and outer edges of the annular zone FZ with dashed lines. It can be understood that the two annular electrodes located on the inner and outer edges of the annular zone FZ are the first annular electrodes 111, and the annular electrode between the two first annular electrodes 111 is the second annular electrode 112.

[0100] Referring to Figure 4, for example, within the same annular region FZ, there may be only one second annular electrode 112, or there may be two or more second annular electrodes 112. It is understood that the number of second annular electrodes 112 within each annular region FZ can be designed according to the control requirements of the liquid crystal molecules, and this disclosure does not impose any limitations on this. For example, only one annular region FZ may have a second annular electrode 112, or multiple annular regions FZ may have a second annular electrode 112, such as all annular regions FZ having a second annular electrode 112; this disclosure does not impose any limitations on this.

[0101] Referring to Figures 1 and 4, in some examples, at least one second annular electrode 112 is located within at least one annular zone FZ near the center of the annular electrode among multiple annular zones FZ. Based on the phase delay period design of a Fresnel lens equivalent to an optical structure, the width of the Fresnel zone regions is smaller towards the edges, thus the width of the annular zone FZs is also smaller. Moreover, when using optical structures to reduce spherical aberration, the width of the annular zone FZs near the edges can be designed to be smaller than the width of the annular zone FZs near the center to achieve large-angle refraction of light. Therefore, when the width of the annular zone FZs near the edges is smaller, the spacing between two adjacent first annular electrodes 111 is relatively small, so that the second annular electrode 112 can be omitted in the annular zone FZs near the edges, thereby simplifying the arrangement of the annular electrodes and reducing costs.

[0102] It is understandable that, depending on actual needs, each annular zone can also be designed to have the same width to facilitate the refined design of the annular electrode near the central electrode. The arrangement of the second annular electrode can be designed according to different needs in different situations. For example, a second annular electrode can be provided in all annular zones, and this disclosure does not impose any limitations on this.

[0103] Figures 5A to 5E are schematic planar views of the annular electrode in the first electrode layer of the optical structure provided in different examples of at least one embodiment of this disclosure.

[0104] Figures 5A to 5E schematically illustrate three ring electrodes, namely ring electrode 1101, ring electrode 1102 and ring electrode 1103.

[0105] Figure 5A is used as an example for illustration. Referring to Figure 5A, in some examples, along the direction from the center of the ring electrode to the edge, the spacing between two adjacent ring electrodes gradually decreases. For example, the spacing between ring electrode 1101 and ring electrode 1102 is spacing D1, and the spacing between ring electrode 1102 and ring electrode 1103 is spacing D2, where spacing D1 is greater than spacing D2. Therefore, based on the phase delay period design method of a Fresnel lens equivalent to an optical structure, the spacing between adjacent ring electrodes can be designed to achieve precise arrangement of ring electrodes.

[0106] For example, the spacing between two adjacent ring electrodes refers to the vertical distance between the outer edge of the ring electrode closer to the center and the inner edge of the ring electrode farther from the center in the direction from the center of the ring electrode to the edge.

[0107] It should be noted that the gradual decrease in the embodiments of this disclosure refers to a gradual decrease in the overall trend, but this disclosure does not limit the local increase or decrease trend, which will not be repeated hereafter.

[0108] Taking the spacing between adjacent ring electrodes as an example, from an overall perspective, the spacing between two adjacent ring electrodes gradually decreases from the center to the edge. However, this does not mean that the spacing between two adjacent ring electrodes farther from the center is necessarily smaller than the spacing between two adjacent ring electrodes closer to the center. For example, the spacing between two adjacent ring electrodes farther from the center can be equal to or greater than the spacing between two adjacent ring electrodes closer to the center. In other words, as long as the overall decreasing trend is not affected, the embodiments of this disclosure do not limit the local arrangement of multiple ring electrodes.

[0109] Referring to Figure 5A, in some examples, the width of multiple ring electrodes gradually decreases along the direction from the center to the edge. For example, the width W1 of ring electrode 1101 is greater than the width W2 of ring electrode 1102. Similarly, the width W2 of ring electrode 1102 is greater than the width W3 of ring electrode 1103. Making the ring electrodes thinner allows for more precise control of the deflection of liquid crystal molecules, resulting in a Fresnel zone region formed by the optical structure that more closely resembles the morphology of an ideal Fresnel zone. This not only improves the accuracy of the optical structure in deflecting light but also enhances luminous efficiency.

[0110] Figure 5B schematically illustrates a ring electrode with a notch, Figure 5C schematically illustrates a ring electrode with a regular hexagon, Figure 5D schematically illustrates a ring electrode with a regular hexagon and a notch, and Figure 5E schematically illustrates a ring electrode with a non-regular polygon and an axis of symmetry. It is understood that Figures 5B and 5D schematically show a ring electrode with two notches; however, this disclosure does not limit the number, location, or shape of the notches in the ring electrode.

[0111] Referring to Figure 1 and in conjunction with Figure 5A, in some examples, the light-shielding pattern 400 includes multiple light-shielding rings 410. Along the direction from the center of the annular electrode to the edge, the spacing between adjacent light-shielding rings 410 gradually decreases. As the width of the annular region FZ gradually decreases, the spacing between the first annular electrodes 111 also gradually decreases accordingly. By designing the spacing between adjacent light-shielding rings 410, the multiple light-shielding rings 410 and the multiple first annular electrodes 111 can be better matched, thereby improving the stray light blocking effect.

[0112] Referring to Figure 1 and in conjunction with Figure 5A, in some examples, the light-shielding pattern 400 includes a plurality of light-shielding rings 410, the width of which gradually decreases along the direction from the center of the annular electrode to the edge. When the width of the plurality of annular electrodes gradually decreases, the width of the light-shielding rings 410 can also be correspondingly gradually decreased to achieve a good match with the corresponding first annular electrode 111.

[0113] Based on the previous example, by designing the width and arrangement of the ring electrodes, the morphology of the Fresnel band obtained by equivalent fitting of the optical structure can be more accurate. In this case, the light-shielding pattern corresponding to the ring electrodes can more accurately block the tooth tips of the equivalent Fresnel teeth, thereby improving the blocking effect on stray light. For example, while meeting the requirements for blocking stray light, the light-shielding rings in the light-shielding pattern can be designed to be narrower, which is beneficial to improving the light extraction efficiency.

[0114] For example, the width of multiple ring electrodes can decrease from the center to the edge, and the spacing between adjacent ring electrodes can also decrease from the center to the edge. Thus, multiple ring electrodes can be arranged in a way that increases in density from the center to the edge, and the light-shielding rings can also be arranged in a way that increases in density from the center to the edge.

[0115] For example, the shape of the light-shielding ring in the light-shielding pattern can match the shape of the annular electrode, such as being the same. For example, when the annular electrode is a circular ring as shown in Figures 5A and 5B, the shape of the light-shielding ring can also be a circular ring. When the annular electrode is a regular hexagonal ring as shown in Figures 5C and 5D, the shape of the light-shielding ring can also be a regular hexagonal ring. When the annular electrode is a non-regular polygon as shown in Figure 5E, the shape of the light-shielding ring can also be a non-regular polygon.

[0116] Figure 6A is a cross-sectional schematic diagram of an optical structure provided in at least one embodiment of the present disclosure. Figure 6B is a partial planar schematic diagram of the first electrode layer and the high-resistivity layer in the optical structure shown in Figure 6A.

[0117] The optical structure shown in Figure 6A differs from the optical structure shown in Figure 1 in that a high-resistivity layer is incorporated in the optical structure shown in Figure 6A. Figure 6A schematically illustrates the liquid crystal molecules (LC) in the liquid crystal layer, omitting the phase retardation distribution curve. Apart from the high-resistivity layer, the other films or structures in the optical structure shown in Figure 6A can be identical to those in the optical structure shown in Figure 1. However, this disclosure does not limit this; the films or structures in the optical structure shown in Figure 6A can also be configured differently from those in the optical structure shown in Figure 1, as needed.

[0118] Referring to Figures 6A and 6B, in some examples, the optical structure further includes a high-resistivity layer 500, which includes a high-resistivity portion 510 located in the gap between two adjacent annular electrodes in the same layer and connected between the two adjacent annular electrodes. Due to the discretized distribution of the annular electrodes, abrupt changes in the electric field can occur, leading to a discontinuous distribution of the phase retardation, which may cause wavefront aberrations. By setting the high-resistivity layer 500 and positioning the high-resistivity portion 510 of the high-resistivity layer 500 in the gap between two adjacent annular electrodes, the resistivity characteristics of the high-resistivity layer 500 can be utilized to form a continuous resistive grid between adjacent annular electrodes. This allows the electric field lines to be uniformly distributed between the first electrode layer 100 and the second electrode layer 200, reducing edge field concentration and linearizing the voltage gradient. Thus, the high-resistivity layer 500 can smooth the electric field distribution and improve the continuity of the phase retardation distribution.

[0119] Referring to Figures 6A and 6B, for example, the high-resistivity portion 510 located between two adjacent ring electrodes can be in direct contact with each of the two ring electrodes.

[0120] For example, in the absence of a high-resistivity layer, a transparent insulating layer can be provided in the gap between two adjacent annular electrodes.

[0121] For example, a high-resistivity layer is a transparent conductive layer with a resistivity of approximately 10. 6 Ω / □ to 109 Ω / □. For example, the material of the high-resistivity layer may include ITO-doped amorphous silicon, ITO-doped zinc oxide, etc., and this disclosure does not limit it.

[0122] For example, the potential distribution satisfies the Laplace equation: in, The voltage inside the high-resistivity section. Let L be the voltage outside the high-resistivity section, L be the width of the gap between the ring electrodes, and x be the position coordinate. The voltage difference between the ring electrodes is divided by the high-resistivity section, forming a smooth potential distribution. At the same time, the high-resistivity layer can also extend the effective electric field range and suppress the phase jump at the edge of the Fresnel band.

[0123] For example, when using a high-resistivity layer, a driving voltage frequency of 1 kHz to 10 kHz can be matched. The thickness of the high-resistivity layer can be 50 nm to 200 nm to reduce optical efficiency loss while ensuring voltage division, such as achieving a transmittance of greater than 90% for the optical structure. In optical structures with a high-resistivity layer, the RMS value fluctuation of the image can be reduced by 30% to 50% compared to optical structures without a high-resistivity layer (e.g., from 0.1 times the reference wavelength to 0.05 times the reference wavelength).

[0124] For example, Figure 6A schematically shows that the thickness of the high-resistivity layer is substantially the same as the thickness of the annular electrode, but this disclosure is not limited thereto. For example, when the resistance of the high-resistivity layer is less than 10... 11 When the resistance is ohms, the thickness of the high-resistivity layer can be less than the thickness of the ring electrode. It is understood that when the high-resistivity layer comprises multiple high-resistivity sections, and these sections are located within the intervals between corresponding adjacent ring electrodes, there is a gap between adjacent high-resistivity sections. That is, the ring electrode separates adjacent high-resistivity sections, preventing them from directly contacting each other and thus preventing short circuits.

[0125] Figures 7 and 8 are schematic cross-sectional views of optical structures provided in at least one embodiment of this disclosure, representing different examples.

[0126] The optical structure shown in Figure 7 differs from the optical structure shown in Figure 1 in that the first electrode layer in the optical structure shown in Figure 7 comprises multiple sublayers. Figure 7 also schematically illustrates the liquid crystal molecules (LC) in the liquid crystal layer, omitting the phase retardation distribution curve. Apart from the first electrode layer, the other films or structures in the optical structure shown in Figure 7 can be identical to those in the optical structure shown in Figure 1. However, this disclosure does not limit this, and the films or structures in the optical structure shown in Figure 7 can also be configured to differ from those in the optical structure shown in Figure 1, as needed.

[0127] Referring to Figure 7, in some examples, the first electrode layer 100 includes at least two sublayers, with at least two of the multiple ring electrodes located in different sublayers. Adjacent ring electrodes within the same layer need to be spaced apart to prevent short circuits. It is understood that due to process limitations, the spacing between adjacent ring electrodes within the same layer has a lower limit, which also restricts the arrangement of the ring electrodes. By arranging the ring electrodes in multiple sublayers, the electrode spacing limit of a single layer can be overcome. This allows the electric field effects of at least two sublayers to be superimposed, enabling the liquid crystal molecules in the liquid crystal layer 300 to generate more precise and smooth phase modulation. This not only increases the design freedom of the multiple ring electrodes but also improves phase transitions, reduces stray light generation, and enhances the focusing efficiency and optical performance of the optical structure. Simultaneously, by designing the first electrode layer 100 to include at least two sublayers, the voltage required to modulate the liquid crystal molecules to achieve the maximum phase difference can be reduced, power consumption can be lowered, and scattering caused by the lateral electric field can be reduced.

[0128] For example, Figure 7 schematically shows that the first electrode layer 100 may include only two sublayers (sublayer 101 as shown in Figure 7) to facilitate the thinning of the optical structure. However, this disclosure is not limited to this, and the first electrode layer 100 may also include three or more sublayers. For example, in the case where the first electrode layer 100 includes only two sublayers, some of the multiple ring electrodes may be located in one layer, and other ring electrodes may be located in another layer. For example, each sublayer may contain only one ring electrode or multiple ring electrodes. It is understood that as long as the performance of the optical structure can be improved by setting at least two sublayers, this disclosure does not limit the number of sublayers, the arrangement and number of ring electrodes in each sublayer, etc.

[0129] It should be noted that when the first electrode layer 100 is configured to include at least two sub-layers, the first annular electrode 111 can be located in any of the sub-layers. It is understood that when designing the arrangement of the annular electrodes, the position of the first annular electrode 111 can be determined primarily based on the distance (e.g., radial dimension) between the centerline of the first annular electrode 111 and the center of the annular electrode. In other words, the position of the first annular electrode 111 in the stacking direction has virtually no impact on the formation of the Fresnel zone region of the optical structure.

[0130] Referring to Figure 7, in some examples, at least two sublayers include a first sublayer 101a and a second sublayer 101b, and multiple annular electrodes include multiple first sub-electrodes 1101 and multiple second sub-electrodes 1102. The multiple first sub-electrodes 1101 are located in the first sublayer 101a, and the multiple second sub-electrodes 1102 are located in the second sublayer 101b. Among the multiple first sub-electrodes 1101 and multiple second sub-electrodes 1102, the annular electrode located at the edge of each annular zone FZ is the first annular electrode 111. In conjunction with the foregoing examples, it can be understood that the first sub-electrode 1101 can be located at the edge of the annular zone FZ to serve as the first annular electrode 111, and the second sub-electrode 1102 can also be located at the edge of the annular zone FZ to serve as the first annular electrode 111; this disclosure does not limit this.

[0131] For example, Figure 7 schematically shows the second sublayer 101b located between the first sublayer 101a and the liquid crystal layer 300, but this disclosure is not limited thereto. The positions of the first sublayer 101a and the second sublayer 101b may also be interchanged, and this disclosure does not limit this.

[0132] Referring to Figure 7, in some examples, in the stacking direction, the spacing between adjacent second sub-electrodes 1102 of the first sub-electrode 1101 overlaps with that of the plurality of second sub-electrodes 1102. For example, in a plane perpendicular to the stacking direction, the orthographic projection of the first sub-electrode 1101 lies between the orthographic projections of two adjacent second sub-electrodes 1102. Thus, in a plane perpendicular to the stacking direction, the distribution of the first sub-electrodes 1101 and the second sub-electrodes 1102 is closer to continuous, which can effectively improve the voltage jump caused by the discrete distribution of electrodes. Moreover, setting the ring electrodes to be distributed in multiple sub-layers can also reduce the manufacturing difficulty, as the spacing between ring electrodes in the same layer can be relatively large.

[0133] Referring to Figure 7, in some examples, a portion of the first sub-electrode 1101 overlaps with a portion of the second sub-electrode 1102 in the stacking direction. For example, on a plane perpendicular to the stacking direction, the orthographic projection of the first sub-electrode 1101 covers the edge of the orthographic projection of the second sub-electrode 1102, so that the orthographic projections of the first sub-electrode 1101 and the second sub-electrode 1102 can together form a gapless circular orthographic projection. This reduces the difficulty of aligning the first sub-electrode 1101 and the second sub-electrode 1102 in the stacking direction, and the smoother potential distribution effectively improves the phase transition at the equivalent Fresnel band edge, reducing stray light generation. Furthermore, setting the first sub-electrode 1101 to overlap a portion of the second sub-electrode 1102 in the stacking direction also reduces the difficulty of aligning the gap between the first sub-electrode 1101 and the adjacent second sub-electrode 1102, preventing gaps between the first sub-electrode 1101 and the second sub-electrode 1102 due to process variations.

[0134] It is understandable that in other examples, there may be a gap between the first sub-electrode 1101 and the second sub-electrode 1102 in the stacking direction, or the edge of the first sub-electrode 1101 may be aligned with the edge of the second sub-electrode 1102.

[0135] Referring to Figure 7, in some examples, the optical structure includes a first high-resistivity structure 501 and a second high-resistivity structure 502. For example, the first high-resistivity structure 501 and the second high-resistivity structure 502 may include the same material and have the same properties. For example, the first high-resistivity structure 501 and the second high-resistivity structure 502 may include the same material and have the same properties as the high-resistivity layer 500 in the aforementioned examples. However, the first high-resistivity structure 501 and the second high-resistivity structure 502 may also be configured to include different materials and have different properties, such as being different from the high-resistivity layer 500, as needed. This disclosure does not impose any limitations on this.

[0136] Referring to Figure 7, in some examples, a first high-resistivity structure 501 is located in the interval between two adjacent first sub-electrodes 1101 of a plurality of first sub-electrodes 1101, and is connected between two adjacent first sub-electrodes 1101. For example, the first high-resistivity structure 501 can be in direct contact with two adjacent first sub-electrodes 1101 respectively. A second high-resistivity structure 502 is located in the interval between two adjacent second sub-electrodes 1102 of a plurality of second sub-electrodes 1102, and is connected between two adjacent second sub-electrodes 1102. For example, the second high-resistivity structure 502 can be in direct contact with two adjacent second sub-electrodes 1102 respectively. By setting the first high-resistivity structure 501 and the second high-resistivity structure 502, the electric field lines can be uniformly distributed between the first electrode layer 100 and the second electrode layer 200, reducing the concentration of the edge field strength and linearizing the voltage gradient. This smooths the electric field distribution and improves the continuity of the phase delay distribution.

[0137] It is understood that Figure 7 schematically illustrates an optical structure including a first high-resistivity structure 501 and a second high-resistivity structure 502. However, this disclosure is not limiting in this regard, and the optical structure may include only the first high-resistivity structure 501 and exclude the second high-resistivity structure 502, or only the second high-resistivity structure 502 and exclude the first high-resistivity structure 501. As long as the electric field distribution can be smoothed using either the first high-resistivity structure 501 or the second high-resistivity structure 502, this disclosure does not limit the specific arrangement of the structure.

[0138] In some examples, the second electrode layer 200 is a common electrode. Referring to Figures 1, 6A, and 7, the second electrode layer 200 includes a surface electrode. This simplifies the design of the second electrode layer 200.

[0139] The optical structure shown in Figure 8 differs from the optical structure shown in Figure 6A in that the second electrode layer 200 in the optical structure shown in Figure 8 includes an electrode pattern 210. Apart from the second electrode layer 200, the other films or structures in the optical structure shown in Figure 8 can be identical to those in the optical structure shown in Figure 6A. However, this disclosure does not limit this, and the films or structures in the optical structure shown in Figure 8 can also be configured to be different from those in the optical structure shown in Figure 6A, as needed.

[0140] Referring to Figure 8, in some examples, the second electrode layer 200 includes an electrode pattern 210 that overlaps with the electrode spacing between two adjacent annular electrodes in the stacking direction. This improves the continuity of the electric field distribution between the first electrode layer 100 and the second electrode layer 200, thereby enhancing the control over the liquid crystal molecules.

[0141] Referring to Figure 8, for example, the electrode pattern 210 can overlap with the edges of two adjacent annular electrodes, thereby reducing alignment difficulty and saving costs. For example, the electrode pattern 210 may include multiple electrode rings, which may be located in the electrode spacing in the stacking direction.

[0142] It should be noted that in other examples, the electrode pattern may also include electrodes of other shapes, which can be matched with the corresponding first electrode layer to form other optical structures. For example, the electrode pattern may include multiple strip electrodes, thereby forming a liquid crystal off-center lens using a first electrode layer including multiple annular electrodes, a liquid crystal layer, and a second electrode layer including multiple strip electrodes. For example, the first electrode layer may also include electrodes of other shapes, such as bent and extended strip electrodes, which can cooperate with the second electrode layer including multiple strip electrodes and the liquid crystal layer to form a liquid crystal elliptical lens. This disclosure does not impose any limitations in this regard.

[0143] Figures 9A to 11B are partial schematic diagrams of optical structures provided in different examples of at least one embodiment of this disclosure.

[0144] It should be noted that Figures 9A, 10A, and 11A only schematically show the relative positional relationship between the center line of the first annular electrode and the spacer. Figures 9B, 10B, and 11B schematically show the spacer and schematically show the phase retardation distribution curve under the action of the electric field with dashed lines, while omitting the liquid crystal molecules in the liquid crystal layer.

[0145] Referring to Figures 9A to 11B, in some examples, the optical structure also includes a photo spacer 600 located between the first electrode layer 100 and the second electrode layer 200. Providing the photo spacer 600 between the first electrode layer 100 and the second electrode layer 200 helps to improve the uniformity of the cell thickness of the liquid crystal cell.

[0146] When a spacer 600 is disposed between the first electrode layer 100 and the second electrode layer 200, there is essentially no liquid crystal molecule distribution at the location of the spacer 600, and the phase retardation at this location is essentially uncontrolled by the electric field. To reduce the impact of the spacer 600 on the light efficiency, the placement of the spacer 600 is designed, for example, to place it at a location with a high phase retardation and a relatively gradual change in phase retardation, thereby reducing the impact of the spacer 600 on the continuity of the phase distribution.

[0147] Referring to Figures 9A and 9B, in some examples, the optical structure is configured to switch between positive and negative optical power, with the orthographic projection of the spacer 600 overlapping the orthographic projection of the first annular electrode 111 on a plane perpendicular to the stacking direction. By setting the spacer 600 to overlap with the first annular electrode 111 in the stacking direction, it is possible to accommodate both positive and negative optical power in the optical structure. That is, the spacer 600 can be placed near the edge of the annular region FZ to minimize its impact on the phase retardation.

[0148] For example, on a plane perpendicular to the stacking direction, the orthographic projection of the spacer 600 may overlap with the orthographic projection of the center line of the first annular electrode 111.

[0149] Referring to Figures 10A and 10B, in some examples, the optical structure is configured to have positive optical power. In a plane perpendicular to the stacking direction, the orthographic projection of the first annular electrode 111 has a center line, and the orthographic projection of the spacer 600 is located on the side of the center line away from the center of the annular zone FZ. When the optical structure has positive optical power, the phase distribution within each annular zone FZ tends to decrease first and then increase from the center towards the edge. Therefore, the spacer 600 can be positioned outside the edge of the annular zone FZ, that is, on the side of the center line of the first annular electrode 111 away from the center of the annular electrode. For example, in a plane perpendicular to the stacking direction, the center line of the orthographic projection of the spacer 600 can be located outside the center line of the orthographic projection of the first annular electrode 111, that is, on the side away from the center of the annular electrode.

[0150] Referring to Figures 11A and 11B, in some examples, the optical structure is configured to have negative optical power. In a plane perpendicular to the stacking direction, the orthogonal projection of the first annular electrode 111 has a center line, and the orthogonal projection of the spacer 600 is located on the side of the center line near the center of the annular zone FZ. When the optical structure has negative optical power, the phase distribution within each annular zone FZ tends to increase first and then decrease from the center towards the edge. Therefore, the spacer 600 can be disposed inside the edge of the annular zone FZ, that is, on the side of the center line of the first annular electrode 111 near the center of the annular electrode. For example, in a plane perpendicular to the stacking direction, the center line of the orthogonal projection of the spacer 600 can be located inside the center line of the orthogonal projection of the first annular electrode 111, that is, on the side near the center of the annular electrode.

[0151] Figures 9B, 10B, and 11B schematically show that the cross-section of the spacer 600 is approximately inverted trapezoidal, meaning that the area of ​​the surface of the spacer 600 facing the second electrode layer 200 is larger than the area of ​​the surface of the spacer 600 facing the first electrode layer 100. However, this disclosure is not limited thereto. Depending on the thickness of the liquid crystal layer 300, the manufacturing process of the spacer 600 (such as forming it on the first electrode layer 100 or the second electrode layer 200), etc., the cross-section of the spacer 600 may also be rectangular or trapezoidal, meaning that the area of ​​the surface of the spacer 600 facing the second electrode layer 200 may be equal to or smaller than the area of ​​the surface of the spacer 600 facing the first electrode layer 100. This disclosure does not impose any limitations on these aspects.

[0152] It is understood that the spacer 600 can have a certain degree of elasticity to facilitate support between the first electrode layer 100 and the second electrode layer 200, maintaining the cell thickness of the liquid crystal cell. Meanwhile, when the thickness of the first electrode layer 100 is small, such as when the material of the first electrode layer 100 includes ITO, the spacer 600 can be entirely located on the annular electrode, or it can be partially located on the annular electrode and partially located on the substrate supporting the annular electrode; this disclosure does not impose any limitations on this.

[0153] For example, Figures 9A, 10A, and 11A schematically show the center lines of five first annular electrodes 111, and schematically show four evenly distributed spacers 600 disposed on the center line of each first annular electrode 111 to facilitate uniform support between the first electrode layer 100 and the second electrode layer 200. However, this disclosure is not limiting in this regard; for example, fewer or more spacers 600 may be disposed on the center line of a first annular electrode 111. For example, the distribution of the spacers 600 may be adjusted according to actual needs. As long as the spacers 600 can be used to maintain the cell thickness of the liquid crystal cell, this disclosure is not limiting in this regard.

[0154] Figure 12 is a partial structural schematic diagram of an optical structure provided in at least one embodiment of the present disclosure.

[0155] Referring to Figure 12, for example, the optical structure also includes an optical film assembly 700. The optical film assembly 700 includes a plurality of first optical films 710 and a plurality of second optical films 720, which are alternately arranged. The first optical films 710 and the second optical films 720 have different refractive indices. By alternately arranging optical films with different refractive indices, multiple reflected beams can be generated in the optical film assembly 700. Through interference effects, these reflected beams are destructively interfered over a wide wavelength range. Therefore, the average reflectivity can be reduced to below 0.5%, or even to 0.1%, across the entire visible light spectrum. Consequently, the transmittance of the optical structure is improved, achieving a transmittance of over 92%.

[0156] For example, the first optical film may include a high-refractive-index material, such as silicon nitride. The second optical film may include a low-refractive-index material, such as silicon dioxide. Thus, by alternating deposition of high-refractive-index and low-refractive-index materials through an anti-reflection and anti-reflection process, the transmittance of the optical structure can be improved.

[0157] For example, the optical film assembly can be disposed between the second electrode layer and the second substrate, such as between the light-shielding pattern and the second substrate.

[0158] The inventors of this application discovered in their research that the performance of liquid crystal devices is easily affected by temperature. For example, when the temperature changes from 20°C to 60°C, the difference between the unusual refractive index and the ordinary refractive index, Δn, may change by up to 20%, which will have a significant impact on optical imaging systems.

[0159] To maintain stable performance under different environmental conditions (such as temperature, humidity, vibration, etc.), the following methods can be adopted. For example, the liquid crystal layer can use wide-temperature liquid crystal molecules. For example, the phase and refractive index differences of the liquid crystal material in the range of -20℃ to 60℃ can be suppressed by using nanoparticles (such as SiO2). For example, a device substrate with a low coefficient of thermal expansion can be used to facilitate matching the thermal deformation characteristics of the liquid crystal layer. For example, thermal compensation films can be added to both sides of the liquid crystal cell, and the phase retardation of the thermal compensation film can be used to offset the focal length shift caused by temperature.

[0160] For example, in the design of optical devices, miniature temperature sensors can be integrated, and temperature-sensitive semiconductor structures such as PN junctions can be used to match a driving voltage that can be matched with the current temperature, and the voltage scheme can be dynamically adjusted to compensate for phase delay.

[0161] For example, ultraviolet (UV) curing sealing technology can be used to increase the stability of the cell thickness of the liquid crystal cell and control the cell thickness variation rate to be less than 0.1 micrometers / ℃.

[0162] Figure 13 is a schematic diagram of an optical system provided in at least one embodiment of the present disclosure.

[0163] Referring to Figure 13, at least one embodiment of this disclosure provides an optical system including the aforementioned optical structure LCF and at least two lenses. It is understood that the optical structure LCF can be the same as the optical structure in any of the foregoing examples. The optical structure LCF and the at least two lenses are arranged on the optical axis of the optical system, with the optical structure LCF located between two adjacent lenses. By setting an optical structure LCF including lenses, ±3D adjustment at a reference optical power can be achieved according to the actual application scenario without adding a mechanical adjustment mechanism.

[0164] Furthermore, since the optical system according to the embodiments of this disclosure includes the above-described optical structure, it also has corresponding beneficial technical effects, which will not be elaborated here.

[0165] For example, Figure 13 schematically shows an optical system comprising two lenses, namely lens L1 and lens L2. However, this disclosure is not limited thereto. Depending on actual needs, the optical system may include more lenses, and the relative positional relationship between the lenses and the optical structure LCF may be designed according to actual needs. This disclosure does not impose any limitations on this.

[0166] For example, the deviation between the optical structure and the optical axes of multiple lenses should not exceed 0.01 mm to achieve good assembly accuracy. For instance, in some optical systems with high haze requirements, the thickness of the liquid crystal cell in the optical structure can be designed to be less than 10 micrometers. This prevents significant gravity imbalances when the optical system needs to be placed vertically in special scenarios, and avoids defects caused by uneven assembly leading to center misalignment of the optical structure. In some optical systems that require horizontal placement and high optical power modulation, such as optical systems used for inspection on industrial production lines, the thickness of the liquid crystal cell in the optical structure can be greater than 10 micrometers to achieve a wider range of optical power modulation.

[0167] For example, at least two lenses may include a lens with positive optical power (lens L1 as shown in Figure 13) and a lens with negative optical power (lens L2 as shown in Figure 13) to reduce or even eliminate chromatic aberration. For example, the difference in Abbe number between the lens with positive optical power and the lens with negative optical power can be no less than 20. Furthermore, designing the combination of optical powers of multiple lenses can help correct defects such as field curvature and distortion, and improve the value of the modulation transfer function (MTF). The value of the modulation transfer function can also be called resolution, which is the ability to resolve details of a photographic object. It is a physical quantity that can be used to describe the ability of a miniature photography system to reproduce fine details of the original object. The higher the MTF value, the better the imaging quality of the optical system.

[0168] For example, lenses can be made of optical glass or resin materials. For instance, lenses can have a fixed curvature and optical power to correct aberrations (such as spherical aberration, chromatic aberration, etc.) and to provide basic optical performance. Furthermore, the high transmittance and stable physical properties of lenses contribute to the imaging stability of the optical system.

[0169] For example, optical structures including liquid crystal layers have virtually no impact on optical transmittance when focusing is not required. For instance, the transmittance of an optical structure can exceed 90% for light with a wavelength of 587 nanometers. Furthermore, the optical structure has a small mass and minimal impact on the overall weight of the optical system. When focusing is required using the optical structure, the liquid crystal molecules within the liquid crystal layer can respond rapidly to an electric field, achieving millisecond-level switching of optical power and enabling continuous changes in optical power.

[0170] By combining at least two lenses with the optical structure, such as through joint optimization based on the target focal length modulation range, clear imaging can be achieved while being compatible with multiple optical powers, thus meeting the focusing and imaging requirements of the optical system.

[0171] For example, an optical system may also include an aperture, which can be used to control the size of the aperture through which light passes, thereby allowing adjustment of the beam diameter and focusing angle.

[0172] At least one embodiment of this disclosure provides a display device including the optical system described above. Since the display device according to the embodiments of this disclosure includes the optical system described above, it also has corresponding beneficial technical effects, which will not be elaborated further here.

[0173] For example, the display device can be any product or component with display function, such as a television, digital camera, mobile phone, watch, tablet computer, laptop computer, or navigator; this embodiment is not limited to this.

[0174] The following points need to be explained:

[0175] (1) The accompanying drawings of the embodiments of this disclosure only involve the structures involved in the embodiments of this disclosure, and other structures can be referred to the general design.

[0176] (2) Where there is no conflict, features of the same embodiment and different embodiments of this disclosure may be combined with each other.

[0177] The above description is merely an exemplary embodiment of this disclosure and is not intended to limit the scope of protection of this disclosure, which is determined by the appended claims.

Claims

1. An optical structure comprising: The first electrode layer includes multiple annular electrodes; The second electrode layer is disposed opposite to the first electrode layer in the stacking direction; A liquid crystal layer is located between the first electrode layer and the second electrode layer; The light-shielding pattern is located on the side of at least one of the first electrode layer and the second electrode layer that is away from the liquid crystal layer; The first electrode layer is divided into multiple annular zones, and the annular electrode corresponding to each annular zone is configured to drive the corresponding liquid crystal molecules in the liquid crystal layer to form the Fresnel zone region of the optical structure. The plurality of annular electrodes includes a first annular electrode located at the edge of each annular region, and in the stacking direction, the light-shielding pattern overlaps at least partially with at least one of the first annular electrodes.

2. The optical structure of claim 1, wherein, In the stacking direction, the centerline of the first annular electrode overlaps with the edge of the corresponding annular region.

3. The optical structure of claim 1 or 2, wherein, The light-shielding pattern includes multiple light-shielding rings; In the stacking direction, the center line of the first annular electrode overlaps with the center line of the corresponding light-shielding ring.

4. The optical structure of claim 3, wherein, The width of the light-shielding ring is smaller than the width of the corresponding first annular electrode; The width of the light-shielding ring is 1.5 micrometers to 6 micrometers, and the width of the first annular electrode is not less than 3.5 micrometers.

5. The optical structure of any of claims 1-4, wherein, The plurality of ring electrodes also includes at least one second ring electrode, which is located between two adjacent first ring electrodes.

6. The optical structure of claim 5, wherein, The at least one second annular electrode is located in at least one annular region of the plurality of annular regions that is close to the center of the annular electrode.

7. The optical structure of any of claims 1-6, wherein, Along the direction from the center of the annular electrode to the edge, the spacing between two adjacent annular electrodes gradually decreases.

8. The optical structure of any of claims 1-7, wherein, The width of the plurality of annular electrodes gradually decreases along the direction from the center of the annular electrode to the edge.

9. The optical structure of any of claims 1-8, wherein, The light-shielding pattern includes multiple light-shielding rings, which point from the center of the annular electrode to the edge, and the spacing between two adjacent light-shielding rings gradually decreases.

10. The optical structure of any of claims 1-9, wherein, The light-shielding pattern includes multiple light-shielding rings, which gradually decrease in width along the direction from the center of the annular electrode to the edge.

11. The optical structure of any of claims 1-10, further comprising a high- resistance layer, wherein, The high-resistivity layer includes a high-resistivity portion located in the gap between two adjacent annular electrodes in the same layer and connected between the two adjacent annular electrodes.

12. The optical structure of any of claims 1-11, wherein, The first electrode layer includes at least two sub-layers, and at least two of the plurality of annular electrodes are located in different sub-layers.

13. The optical structure of claim 12, wherein, The at least two sub-layers include a first sub-layer and a second sub-layer, and the plurality of annular electrodes include a plurality of first sub-electrodes and a plurality of second sub-electrodes, wherein the plurality of first sub-electrodes are located in the first sub-layer and the plurality of second sub-electrodes are located in the second sub-layer; Among the plurality of first sub-electrodes and the plurality of second sub-electrodes, the annular electrode located at the edge of each annular zone is the first annular electrode; In the stacking direction, the first sub-electrode overlaps with the spacing between two adjacent second sub-electrodes among the plurality of second sub-electrodes.

14. The optical structure of claim 13, wherein, In the stacking direction, the first sub-electrode overlaps with a portion of the second sub-electrode.

15. The optical structure according to claim 13 or 14, further comprising a first high-resistivity structure and a second high-resistivity structure; wherein, The first high-resistivity structure is located in the interval between two adjacent first sub-electrodes of the plurality of first sub-electrodes, and is connected between the two adjacent first sub-electrodes; The second high-resistivity structure is located in the interval between two adjacent second sub-electrodes of the plurality of second sub-electrodes, and is connected between the two adjacent second sub-electrodes.

16. The optical structure of any of claims 1-15, wherein, The second electrode layer is a common electrode; The second electrode layer includes a surface electrode, or; The second electrode layer includes an electrode pattern that overlaps with the electrode spacing between two adjacent annular electrodes in the stacking direction.

17. The optical structure according to any one of claims 1-16, further comprising a spacer located between the first electrode layer and the second electrode layer; wherein, The optical structure is configured to switch between positive and negative optical power; On a plane perpendicular to the stacking direction, the orthographic projection of the spacer overlaps with the orthographic projection of the first annular electrode.

18. The optical structure according to any one of claims 1-17, further comprising a spacer located between the first electrode layer and the second electrode layer; wherein The optical structure is configured to have positive optical power; On a plane perpendicular to the stacking direction, the orthographic projection of the first annular electrode has a center line, and the orthographic projection of the spacer is located on the side of the center line away from the center of the annular region.

19. The optical structure according to any one of claims 1-18, further comprising a spacer located between the first electrode layer and the second electrode layer; wherein The optical structure is configured to have negative optical power; On a plane perpendicular to the stacking direction, the orthographic projection of the first annular electrode has a center line, and the orthographic projection of the spacer is located on the side of the center line near the center of the annular region.

20. An optical system: Includes the optical structure according to any one of claims 1-19; At least two lenses; wherein The optical structure and the at least two lenses are arranged on the optical axis of the optical system; The optical structure is located between two adjacent lenses of the at least two lenses.

21. A display device comprising the optical system according to claim 20.

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