Liquid crystal microlens array and driving method therefor, and near-eye display system

Abstract

A liquid crystal microlens array, comprising m1 first electrode strips and m2 second electrode strips, wherein the orthographic projections of the second electrode strips on a liquid crystal layer respectively intersect with the orthographic projections of the first electrode strips on the liquid crystal layer, the m1 first electrode strips are respectively supplied with 1-n1 voltage signals, and the m2 second electrode strips are respectively supplied with 1-n2 voltage signals. By controlling the voltage value of each voltage signal, the rotation angle of liquid crystal molecules of a liquid crystal cell at a corresponding position can be changed, thereby forming an annular phase retardation distribution, and thus forming a curved microlens at each set of n1×n2 intersections. The first electrode strips and the second electrode strips have a strip structure, which is relatively simple to fabricate. By controlling n1 and n2, the shape and size of the curved microlens can be controlled, and the regulation and control precision is relatively high. Further provided are a driving method for the liquid crystal microlens array, and a near-eye display system comprising the liquid crystal microlens array.

Description

Liquid crystal microlens array and driving method thereof, near-eye display system

[0001] Cross-reference to related applications

[0002] The present disclosure claims priority to Chinese Patent Application No. 202411126244.4, filed on August 15, 2024, entitled “Liquid crystal microlens array and driving method thereof, near-eye display system,” the entire contents of which are incorporated herein by reference in their entirety. TECHNICAL FIELD

[0003] The present application relates to the technical field of display, in particular to a liquid crystal microlens array and driving method thereof, near-eye display system. BACKGROUND

[0004] In near-eye display technology, the images received by the left and right eyes can only be planar images, and the depth of field is fixed at a certain position in front of the eyes. As a result, the “appropriate” focal length perceived by the brain does not match the actual focal length perceived by the single eye, resulting in serious internal consumption.

[0005] Therefore, liquid crystal microlenses are introduced to change the imaging position by adjusting the focal length of the liquid crystal microlenses, so that the observer can perceive the change in the distance of the image through the single eye. The current liquid crystal microlens array structure is complex to manufacture and has low control precision.

[0006] It should be noted that the information disclosed in the above BACKGROUND section is only used to enhance the understanding of the background of the present application, and therefore can include information that does not constitute prior art known to those of ordinary skill in the art. SUMMARY

[0007] The purpose of the present application is to overcome the problem of the current liquid crystal microlens array structure being complex to manufacture and having low control precision, and to provide a liquid crystal microlens array and driving method thereof, near-eye display system.

[0008] According to one aspect of the present application, a liquid crystal microlens array is provided, which comprises a liquid crystal cell, m1 first electrode strips and m2 second electrode strips, the liquid crystal cell comprising a liquid crystal layer, a first substrate and a second substrate, the liquid crystal layer having a first surface and a second surface arranged oppositely, the first substrate being arranged on the first surface of the liquid crystal layer, and the second substrate being arranged on the second surface of the liquid crystal layer; the m1 first electrode strips being arranged on the side of the first substrate close to the liquid crystal layer, the first electrode strips extending along a first direction, a plurality of the first electrode strips being arranged along a second direction, the m1 first electrode strips comprising at least one group of first electrode strips, each group of first electrode strips comprising n1 first electrode strips; the m2 second electrode strips being arranged on the side of the second substrate close to the liquid crystal layer, the second electrode strips extending along the second direction, a plurality of the second electrode strips being arranged along the first direction, the m2 second electrode strips comprising at least one group of second electrode strips, each group of second electrode strips comprising n2 second electrode strips; the angle between the second direction and the first direction being greater than 45 degrees and less than 135 degrees, the orthographic projection of each second electrode strip on the first substrate and the orthographic projection of each first electrode strip on the first substrate intersecting with each other respectively; each group of first electrode strips being given 1-n1 voltage signals respectively, each group of second electrode strips being given 1-n2 voltage signals respectively, and one curved surface microlens being formed at each of n1*n2 intersection points, 2≤n1≤m1, and 2≤n2≤m2.

[0009] In one embodiment of the present application, the m1 first electrode strips comprise at least two groups of first electrode strips, and the m2 second electrode strips comprise at least two groups of second electrode strips, at least four curved surface microlenses being formed at the m1*m2 intersection points by controlling the voltage values of the voltage signals.

[0010] In one embodiment of the present application, the distance between adjacent two first electrode strips is the same as the distance between adjacent two second electrode strips, when n1=n2, the component of the distance from the center to the edge of the orthographic projection of the curved surface microlens on the first substrate in the first direction is equal to the component in the second direction, the distance between adjacent first electrode strips is equal to the distance between adjacent second electrode strips and is a first distance, and the distance from the center to the edge of the orthographic projection of the curved surface microlens on the first substrate is D=n1*pitch, where pitch is the size of the first distance.

[0011] In one embodiment of the present application, the distance between adjacent two first electrode strips is different from the distance between adjacent two second electrode strips, when n1=n2, when the distance between the first electrode strips is greater than the distance between adjacent two second electrode strips, the component of the distance from the center to the edge of the orthographic projection of the curved surface microlens on the first substrate in the first direction is less than the component in the second direction, and when the distance between the first electrode strips is less than the distance between adjacent two second electrode strips, the component of the distance from the center to the edge of the orthographic projection of the curved surface microlens on the first substrate in the first direction is greater than the component in the second direction.

[0012] In one embodiment of the present application, m1 first electrode strips are applied with 1-n1 voltage signals, m2 second electrode strips are applied with 1-n2 voltage signals, when n1 is greater than n2, the component of the distance from the center to the edge of the orthographic projection of the curved micro-lens on the first substrate in the first direction is less than that in the second direction, when n1 is less than n2, the component of the distance from the center to the edge of the orthographic projection of the curved micro-lens on the first substrate in the first direction is greater than that in the second direction.

[0013] In one embodiment of the present application, the number of each group of first electrode strips is greater than or equal to 10, the number of each group of second electrode strips is greater than or equal to 10, and the distance from the center to the edge of the orthographic projection of the curved micro-lens on the first substrate is 100-2000 μm.

[0014] In one embodiment of the present application, the angle between the second direction and the first direction is greater than 45 degrees and less than 135 degrees.

[0015] According to another aspect of the present application, a driving method of the liquid crystal micro-lens array provided by one aspect of the present application is provided, which comprises: m1 first electrode strips are applied with 1-n1 voltage signals respectively, m2 second electrode strips are applied with 1-n2 voltage signals respectively, at least one curved micro-lens is formed at the m1xm2 intersection points, 2≤n1≤m1, 2≤n2≤m2.

[0016] In one embodiment of the present application, the voltage signal applied to the first electrode strip satisfies the following relationship: Vx=f(x), x is the coordinate of the first electrode strip along the first direction, Vx is the input potential of the first electrode strip at the position; the voltage signal applied to the second electrode strip satisfies the following relationship: Vy=-g(y), y is the coordinate of the first electrode strip along the second direction, Vy is the input potential of the second electrode strip at the position; the potential difference of any point (x, y) in the liquid crystal cell is: ΔV=f(x)-(-g(y))=f(x)+g(y).

[0017] In one embodiment of the present application, f(x)=x 2 , g(y)=y 2 , the potential difference of any point (x, y) in the liquid crystal cell is: ΔV=x 2 +y 2 .

[0018] In one embodiment of the present application, the method further comprises: translating the initial voltage signal of the m1 first electrode strips from x1 to x2 in the first direction, x2>x1, the voltage signal loaded on the first electrode strips satisfies the following relationship: Vx=f(x)+a, a=x2-x1; and / or translating the initial voltage signal of the m2 second electrode strips from y1 to y2 in the second direction, y2>y1, the voltage signal loaded on the second electrode strips satisfies the following relationship: Vy=-g(y)+b, b=y2-y1; so that each curved micro-lens array is translated by a in the first direction and / or by b in the second direction.

[0019] In one embodiment of the present application, the method further comprises: reducing the voltage signal inputted by the first electrode strips and / or reducing the voltage signal inputted by the second electrode strips to reduce the camber height of the curved micro-lens; increasing the voltage signal inputted by the first electrode strips and / or increasing the voltage signal inputted by the second electrode strips to increase the camber height of the curved micro-lens.

[0020] In one embodiment of the present application, the method further comprises: reducing the period n1 of the voltage signal of the first electrode strips and / or reducing the period n2 of the voltage signal of the second electrode strips to reduce the diameter of the curved micro-lens; or increasing the period n1 of the voltage signal of the first electrode strips and / or increasing the period n2 of the voltage signal of the second electrode strips to increase the diameter of the curved micro-lens.

[0021] According to another aspect of the present application, there is provided a near-eye display system comprising a display panel and a liquid crystal micro-lens array provided by one aspect of the present application, the liquid crystal micro-lens array is arranged on the display side of the display panel, and the liquid crystal micro-lens array and the display panel are parallel to each other.

[0022] The aperture of the curved micro-lens satisfies the formula: Sh×n t / L≤D≤S×n t ;

[0023] The focal length of the curved micro-lens satisfies the formula: 1 / f=1 / (h×n t )-1 / H;

[0024] The radius of curvature of the curved micro-lens satisfies the formula: r=f(n e -n o );

[0025] The camber height of the curved micro-lens is:

[0026] wherein D is the aperture of the curved micro-lens, S is the maximum diameter of the pupil, L is the distance between the eyeball and the curved micro-lens, h is the distance between the display panel and the curved micro-lens, n t is the refractive index of the medium between the display panel and the liquid crystal micro-lens array, and f is the focal length of the curved micro-lens.o n is the refractive index of the liquid crystal to ordinary light e n is the refractive index of the liquid crystal to extraordinary light, f is the focal length of the curved microlens, and r is the radius of curvature of the curved microlens.

[0027] In an embodiment of the present application, the near-eye display system further comprises a magnifying lens, which is arranged on the side of the liquid crystal microlens array away from the display panel and close to the eyeball, and is parallel to the liquid crystal microlens array.

[0028] In an embodiment of the present application, the near-eye display system further comprises a free-form mirror, and the display panel and the liquid crystal microlens array are arranged obliquely between the free-form mirror and the eyeball, and the free-form mirror is located on the emergent light of the liquid crystal microlens array, and the emergent light is reflected to the eyeball by the microlens array.

[0029] The liquid crystal microlens array of the present application comprises m1 first electrode strips and m2 second electrode strips, the orthographic projection of each second electrode strip on the first substrate intersects the orthographic projection of each first electrode strip on the first substrate, respectively, m1 first electrode strips are respectively given 1-n1 voltage signals, and m2 second electrode strips are respectively given 1-n2 voltage signals, and the rotation angle of the liquid crystal molecules of the liquid crystal box at the position can be changed by controlling the voltage value of the voltage signal, a ring-shaped phase delay distribution is formed, and thus a curved microlens is formed at each n1*n2 intersection. The first electrode strip and the second electrode strip are in a strip structure, which is relatively simple to manufacture, the shape and size of the curved microlens can be controlled by controlling the size of n1 and n2, and the control precision is relatively high.

[0030] It should be understood that the foregoing general description and the following detailed description are only exemplary and explanatory, and cannot limit the present application. BRIEF DESCRIPTION OF DRAWINGS

[0031] The drawings incorporated into the specification and constituting a part of the specification show embodiments consistent with the present application and, together with the specification, serve to explain the principles of the present application. Obviously, the drawings in the following description are only some embodiments of the present application, and other drawings can be obtained from these drawings without creative labor for those skilled in the art.

[0032] FIG. 1 is a perspective structural schematic view of the voltage signal on the second electrode strip of the liquid crystal microlens array involved in the embodiment of the present application before translation.

[0033] FIG. 2 is a schematic view of m1 first electrode strips and m2 second electrode strips mutually overlapping to form m1*m2 intersections.

[0034] Figure 3 is a schematic diagram of potential difference generated at four intersection points of two first electrode strips and two second electrode strips according to an embodiment of the present application.

[0035] Figure 4 is a schematic diagram of driving electric field according to an embodiment of the present application.

[0036] Figure 5 is a schematic diagram of distribution of annular potential formed by interlacing first electrode strips and second electrode strips according to an embodiment of the present application.

[0037] Figure 6 is a schematic diagram of cross section of liquid crystal microlens array after voltage signal translation on second electrode strips according to an embodiment of the present application.

[0038] Figure 7 is a schematic diagram of cross section of liquid crystal microlens array before voltage signal translation on second electrode strips according to an embodiment of the present application.

[0039] Figure 8 is a schematic diagram of cross section of liquid crystal microlens array after voltage signal translation on second electrode strips according to an embodiment of the present application.

[0040] Figure 9 is a schematic diagram of cross section of equivalent topography of curved microlens before arch height reduction according to an embodiment of the present application.

[0041] Figure 10 is a schematic diagram of cross section of equivalent topography of curved microlens after arch height reduction according to an embodiment of the present application.

[0042] Figure 11 is a schematic diagram of cross section of near-eye display system according to an embodiment of the present application.

[0043] Figure 12 is a schematic diagram of cross section of curved microlens of near-eye display system before aperture reduction according to an embodiment of the present application.

[0044] Figure 13 is a schematic diagram of cross section of curved microlens of near-eye display system after aperture reduction according to an embodiment of the present application.

[0045] Figure 14 is a schematic diagram of cross section of near-eye display system according to an embodiment of the present application when the near-eye display system comprises a magnifying lens.

[0046] Figure 15 is a schematic diagram of cross section of near-eye display system according to an embodiment of the present application when the near-eye display system comprises a free-form mirror.

[0047] In the drawings: 1 - liquid crystal microlens array, 11 - liquid crystal cell, 111 - first substrate, 112 - second substrate, 12 - first electrode strip, 13 - second electrode strip, 101 - curved microlens, 2 - display panel, 3 - magnifying lens, 4 - free-form mirror, 5 - eye. DETAILED DESCRIPTION

[0048] Example implementations will now be described more fully with reference to the accompanying drawings. Example implementations can be implemented in any numerous ways, and example implementations should not be construed as limited to having been set forth in the description herein; rather, descriptions are provided so that this disclosure will be complete and fully convey the concepts of example implementations to those skilled in the art. Identical reference numerals may have been used, where appropriate, to designate identical or similar components that are found throughout the specification and / or drawings. Additionally, the drawings are not necessarily drawn to scale.

[0049] Although relative terms such as "upper," "lower," may be used herein to describe one component's relationship to another component of a figure, such terminology is used herein for convenience only and is not limiting of the claims unless specifically stated otherwise. It will be understood that, when a figure is turned upside down, the component previously described as being on the "upper" side of other elements will then be on the "lower" side of other elements. When a structure is "on" or "under" another structure, that structure can either be directly on or under the other structure or intervening structure(s) can also be present.

[0050] The terms "a," "an," "the" and "at least one" are used to mean one or more of something; the terms "comprises", "comprising", "includes", "including" and the like can mean including but not limited to; the term "first," "second," "third," and the like, merely mean one of or one part of something, and do not require counting or numbering of its objects.

[0051] Virtual Reality (VR) and Augmented Reality (AR) belong to near-eye display system. In the process of near-eye display, the biggest problem is the problem of accommodation adjustment. Specifically, there is a small difference between the left eye image and the right eye image. After the brain analyzes this part of the difference, it immediately gets the approximate information of the distance between the viewing object and the eye. At this time, the lens of the single eye will uncontrollably adjust quickly to ensure that the object the eye focuses on is accurately imaged by each eye. This is a great advantage in the process of natural evolution, which can ensure that the eye locks the object and then quickly and accurately focuses.

[0052] However, in near-eye display systems, accommodation adjustment becomes a disaster. Virtual reality and augmented reality technologies can easily project images with slight angular differences to the left and right eyes, which can deceive the human brain and thus create a stereoscopic effect. However, the human brain receives such stereoscopic images and immediately sends a lens adjustment command to adjust the lens to the "appropriate" focal length range. In existing virtual reality and augmented reality technologies, the images received by the left and right eyes can only be flat images, and the depth of field is fixed at a certain position in front of the eyes. As a result, the "appropriate" focal length range considered by the brain does not match the actual focal length range perceived by the single eye, resulting in serious internal consumption.

[0053] The specific process is as follows:

[0054] 1. The brain determines that the distance between the object and the eye is x meters according to the images of the left and right eyes.

[0055] 2. The brain sends a command to the lenses of both eyes: command the lenses to contract or relax to adjust the focal length to x meters.

[0056] 3. The focal length of the lens is quickly adjusted to x meters, but the actual single-eye image depth is a fixed value of the near-eye display system (assuming y meters), x≠y, causing the retinal image to be blurred.

[0057] 4. The brain finds that the image is blurred and commands the lens to adjust again. When the final focal length is adjusted to y meters, the image is clear.

[0058] 5. The brain again commands the lens to adjust to the focal length of x meters according to the binocular disparity. This cycle is repeated. Such internal consumption not only causes ciliary muscle adjustment fatigue, but also greatly consumes the brain's energy, making people feel tired, dizzy, and overworked, greatly limiting the application of virtual reality and augmented reality technologies.

[0059] Therefore, a liquid crystal microlens array 1 is introduced into the near-eye display system. The liquid crystal microlens array 1 can include a liquid crystal cell 11, a first electrode and a second electrode. The liquid crystal cell 11 can include a first substrate 111, a second substrate 112 and a liquid crystal layer. The first electrode and the second electrode can be arranged on the side of the first substrate 111 and the second substrate 112 close to the liquid crystal layer. By controlling the voltage signals of the first electrode and the second electrode, different potential differences are generated at the corresponding positions on both sides of the liquid crystal cell 11, and a driving electric field is formed along the thickness direction of the liquid crystal cell 11. The driving electric field can change the rotation angle of the liquid crystal molecules of the liquid crystal layer at the position, and the liquid crystal microlens array 1 is formed. The liquid crystal microlens array 1 is arranged on the display side of the display panel 2. By adjusting the focal length of the liquid crystal microlens array 1, the imaging position is changed, and the observer can feel the change of the near and far of the imaging through the single eye. According to the left and right eye images, the depth of field of the near-eye display system is adjusted, so that the "appropriate" focal length considered by the brain matches the actual focal length perceived by the single eye. However, most liquid crystal microlens arrays 1 need to use annular first electrodes and second electrodes. Such structure is complex to manufacture and has low control precision.

[0060] Based on this, the embodiment of the present application provides a liquid crystal microlens array 1. As shown in FIGS. 1 to 15, the liquid crystal microlens array 1 includes a liquid crystal cell 11, m1 first electrode strips 12 and m2 second electrode strips 13. The liquid crystal cell 11 includes a liquid crystal layer, a first substrate 111 and a second substrate 112. The liquid crystal layer has a first face and a second face arranged oppositely. The first substrate 111 is arranged on the first face of the liquid crystal layer, and the second substrate 112 is arranged on the second face of the liquid crystal layer. The m1 first electrode strips 12 are arranged on the side of the first substrate 111 close to the liquid crystal layer. The first electrode strips 12 extend along a first direction. A plurality of first electrode strips 12 are arranged along a second direction. The m1 first electrode strips 12 include at least one group of first electrode strips 12. Each group of first electrode strips 12 includes n1 first electrode strips 12. The m2 second electrode strips 13 are arranged on the side of the second substrate 112 close to the liquid crystal layer. The second electrode strips 13 extend along the second direction. A plurality of second electrode strips 13 are arranged along the first direction. The m2 second electrode strips 13 include at least one group of second electrode strips 13. Each group of second electrode strips 13 includes n2 second electrode strips 13. The angle between the second direction and the first direction is greater than 0 degrees and less than 180 degrees. The orthographic projection of each second electrode strip 13 on the first substrate intersects the orthographic projection of each first electrode strip 12 on the first substrate. Each group of first electrode strips 12 is respectively given 1-n1 voltage signals. Each group of second electrode strips 13 is respectively given 1-n2 voltage signals. A curved surface microlens 101 is formed along the thickness direction of the liquid crystal cell 11 at every n1xn2 intersection. 2≤n1≤m1 and 2≤n2≤m2.

[0061] The orthographic projection of each second electrode strip 13 on the first substrate intersects the orthographic projection of each first electrode strip 12 on the first substrate, m1 first electrode strips 12 are respectively given 1-n1 voltage signals, m2 second electrode strips 13 are respectively given 1-n2 voltage signals, by controlling the voltage value of each voltage signal, the rotation angle of the liquid crystal molecules of the liquid crystal cell 11 at this position can be changed, a ring-shaped phase delay distribution is formed, so that a curved surface microlens 101 is formed at every n1*n2 intersection point. The first electrode strip 12 and the second electrode strip 13 are in a strip-shaped structure, which is relatively simple to manufacture, and by controlling the size of n1 and n2, the shape and size of the curved surface microlens 101 can be controlled, and the adjustment precision is relatively high.

[0062] The liquid crystal microlens array 1 related to the embodiments of the present application will be described in detail below in combination with specific examples.

[0063] As shown in FIG. 1, the liquid crystal microlens array 1 includes a liquid crystal cell 11, the liquid crystal cell 11 including a liquid crystal layer, a first substrate 111 and a second substrate 112, the liquid crystal layer having a first face and a second face arranged oppositely, the first substrate 111 being arranged on the first face of the liquid crystal layer, and the second substrate 112 being arranged on the second face of the liquid crystal layer. The liquid crystal microlens array 1 further includes m1 first electrode strips 12 and m2 second electrode strips 13, the m1 first electrode strips 12 being arranged on the side of the first substrate 111 close to the liquid crystal layer, the first electrode strips 12 extending along a first direction, and a plurality of first electrode strips 12 being arranged along a second direction, and the m2 second electrode strips 13 being arranged on the side of the second substrate 112 close to the liquid crystal layer. m1 can be equal to m2, or m1 can be different from m2, which is not specifically limited here.

[0064] As shown in FIG. 2, the first electrode strips 12 extend along the first direction, the m1 first electrode strips 12 are arranged along the second direction, the second electrode strips 13 extend along the second direction, and the m2 second electrode strips 13 are arranged along the first direction, the angle between the second direction and the first direction being greater than 0 degrees and less than 180 degrees, specifically, the angle between the second direction and the first direction being greater than 45 degrees and less than 135 degrees. The orthographic projection of each second electrode strip 13 on the first substrate intersects the orthographic projection of each first electrode strip 12 on the first substrate, forming m1*m2 intersection points.

[0065] m1 first electrode strips 12 include k1 groups of first electrode strips 12, each group of first electrode strips 12 is respectively given 1-n1 voltage signals, m2 second electrode strips 13 include k2 groups of second electrode strips 13, each group of second electrode strips 13 is respectively given 1-n2 voltage signals, m1≥k1n1, m2≥k2n2, k1≥1, k2≥1. By controlling the voltage value of each voltage signal, a driving electric field is formed in the liquid crystal cell 11 at every n1×n2 intersection. When k1=k2=1, m1=n1, m2=n2, a driving electric field as shown in FIG. 4 is formed in the liquid crystal cell 11 at m1×m2 intersections, and a driving electric field drives liquid crystal molecules to form a curved surface microlens 101.

[0066] When k1=k2=k≥2, k×k driving electric fields are periodically distributed along the thickness direction of the liquid crystal cell 11 at m1×m2 intersections, and multiple driving electric fields drive liquid crystal molecules to form periodically distributed k×k curved surface microlenses 101. For example, when k=2, 2×2 driving electric fields as shown in FIG. 4 are formed, and 2×2 driving electric fields form 2×2 curved surface microlenses 101.

[0067] When k1≠k2, k1×k2 driving electric fields are periodically distributed along the thickness direction of the liquid crystal cell 11 at m1×m2 intersections, and multiple driving electric fields drive liquid crystal molecules to form periodically distributed k1×k2 curved surface microlenses 101. For example, when k1=1, k2=2, 1×2 driving electric fields as shown in FIG. 4 are formed, and 1×2 driving electric fields form 1×2 curved surface microlenses 101.

[0068] In this embodiment, the number of each group of first electrode strips 12 can be greater than or equal to 10, and the number of each group of second electrode strips 13 can be greater than or equal to 10. The distance from the center to the edge of the orthographic projection of the curved surface microlens on the first substrate is 100-2000 μm. For example, when the number of first electrode strips 12 is equal to 10 and the number of second electrode strips 13 is equal to 10, the distance from the center to the edge of the orthographic projection of the curved surface microlens on the first substrate is 100 μm. When the number of first electrode strips 12 is equal to 15 and the number of second electrode strips 13 is equal to 15, the distance from the center to the edge of the orthographic projection of the curved surface microlens on the first substrate is 300 μm. When the number of first electrode strips 12 is equal to 50 and the number of second electrode strips 13 is equal to 50, the distance from the center to the edge of the orthographic projection of the curved surface microlens on the first substrate is 2000 μm.

[0069] As shown in FIG. 3, when m1=n1=2 and m2=n2=2, the liquid crystal microlens array 1 can include 2 first electrode strips 12 and 2 second electrode strips 13, the 2 first electrode strips 12 extending along the first direction, and the 2 second electrode strips 13 extending along the second direction, the 2 first electrode strips 12 and the 2 second electrode strips 13 intersecting with each other to form 2x2 intersection points o1, o2, o3 and o4, respectively.

[0070] The voltage signals of the 2 first electrode strips 12 have sizes a and b, respectively, the voltage signals of the 2 second electrode strips 13 have sizes i and j, respectively, the thickness of the liquid crystal layer is d, the electric field intensity at the intersection points is determined by the potential difference between the first electrode strips 12 and the second electrode strips 13, the potential difference of o1 is E1=(a-i) / d, the potential difference of o2 is E2=(a-j) / d, the potential difference of o3 is E3=(b-i) / d, and the potential difference of o4 is E4=(b-j) / d. By changing the sizes of the voltage signals of the first electrode strips 12 and the voltage signals of the second electrode strips 13, a driving electric field as shown in FIG. 4 is formed at the n1x n2 intersection points. The driving electric field drives the rotation angles of the liquid crystal molecules at different positions to form a curved surface microlens 101.

[0071] When n1=n2, the distance between the adjacent two first electrode strips 12 can be the same as the distance between the adjacent two second electrode strips 13, and the driving liquid crystal molecules form a curved surface microlens 101. In this case, the component in the first direction of the distance from the center to the edge of the orthographic projection of the curved surface microlens 101 on the first substrate 111 can be equal to the component in the second direction.

[0072] When n1=n2 and the distance between the adjacent two first electrode strips 12 is the same as the distance between the adjacent two second electrode strips 13, the distance between the adjacent first electrode strips 12 and the distance between the adjacent second electrode strips 13 are equal and are a first distance, and the distance from the center to the edge of the orthographic projection of the curved surface microlens 101 on the first substrate 111 is D=n1x pitch, where pitch is the size of the first distance.

[0073] The distance between two adjacent first electrode strips 12 and the distance between two adjacent second electrode strips 13 can also be different, in which case the component of the distance from the center to the edge of the orthographic projection of the curved microlens 101 formed by the driving electric field in the liquid crystal cell on the first substrate 111 in the first direction is not equal to the component in the second direction. When the distance between two adjacent first electrode strips 12 is greater than the distance between two adjacent second electrode strips 13, the component of the distance from the center to the edge of the orthographic projection of the curved microlens 101 on the first substrate 111 in the first direction is less than the component in the second direction, and when the distance between two adjacent first electrode strips 12 is less than the distance between two adjacent second electrode strips 13, the component of the distance from the center to the edge of the orthographic projection of the curved microlens 101 on the first substrate 111 in the first direction is greater than the component in the second direction.

[0074] When n1≠n2, m1 first electrode strips 12 are supplied with 1-n1 voltage signals, and m2 second electrode strips 13 are supplied with 1-n2 voltage signals, in which case the component of the distance from the center to the edge of the orthographic projection of the curved microlens 101 formed by the driving electric field in the liquid crystal cell on the first substrate 111 in the first direction is not equal to the component in the second direction. When n1 is greater than n2, the component of the distance from the center to the edge of the orthographic projection of the curved microlens 101 on the first substrate 111 in the first direction is less than the component in the second direction, and when n1 is less than n2, the component of the distance from the center to the edge of the orthographic projection of the curved microlens 101 on the first substrate 111 in the first direction is greater than the component in the second direction.

[0075] In the present embodiment, when n1=n2 and the distance between two adjacent first electrode strips 12 is equal to the distance between two adjacent second electrode strips 13, in which case the orthographic projection of the curved microlens 101 formed by the driving electric field in the liquid crystal cell on the first substrate 111 can be circular, and the distance from the center to the edge of the orthographic projection of the curved microlens 101 on the first substrate 111 is the diameter of the circle. When the distance between two adjacent first electrode strips 12 is different from the distance between two adjacent second electrode strips 13 or n1≠n2, in which case the orthographic projection of the curved microlens 101 formed by the driving electric field in the liquid crystal cell on the first substrate 111 can be elliptical.

[0076] The present embodiment also provides a driving method for a liquid crystal microlens array 1. The method can include:

[0077] m1 first electrode strips 12 are respectively given 1-n1 voltage signals, m2 second electrode strips 13 are respectively given 1-n2 voltage signals, at least one driving electric field is formed along the thickness direction of the liquid crystal cell 11 at m1*m2 intersection points, the at least one driving electric field drives the liquid crystal molecules to form at least one curved surface microlens 101, 2≤n1≤m1, 2≤n2≤m2.

[0078] The voltage signals loaded on the first electrode strips 12 satisfy the following relationship: Vx=f(x), x is the coordinate of the first electrode strip 12 along the first direction, Vx is the input potential of the first electrode strip 12 at this position; the voltage signals loaded on the second electrode strips 13 satisfy the following relationship: Vy=-g(y), y is the coordinate of the first electrode strip 12 along the second direction, Vy is the input potential of the second electrode strip 13 at this position; the potential difference of the driving electric field at any point (x, y) is: ΔV=f(x)-(-g(y))=f(x)+g(y).

[0079] Suppose f(x)=x 2 , g(y)=y 2 , then the potential difference of the driving electric field at any point (x, y) is: ΔV=x 2 +y 2 , and the function image of ΔV=x 2 +y 2 is exactly the three-dimensional driving electric field. f(x) and g(y) can also be adjusted to make the function image of ΔV as circular driving electric field as possible, or other non-circular driving electric field. As shown in FIG. 5, n1=n2=13, number m1 and m2, 1~13~1 is a period, by controlling the input voltage signals of each first electrode strip 12 and the input voltage signals of each second electrode strip 13, a ring-shaped potential distribution E O can be formed, and the potential difference of any point on the ring-shaped potential distribution E O satisfies the function formula ΔV=x 2 +y 2 .

[0080] The advantages of the liquid crystal microlens array 1 are that not only the focal length of the curved surface microlens 101 can be adjusted, but also the position of the curved surface microlens 101 can be adjusted, and the aperture of the curved surface microlens 101 can be changed.

[0081] As shown in FIG. 1 and FIG. 7, the 1-n1 voltage signals of the first electrode strips 12 are -5V, -1V, -5V in turn, in the cross section S1, the corresponding stagger points are formed by one first electrode strip 12 (the voltage signal input by the first electrode strip 12 is -5V), the equivalent topography of the curved micro-lens 101 formed thereby is shown as the dashed line L1. In the cross section S2, the corresponding stagger points are formed by another first electrode strip 12 (the voltage signal input by the first electrode strip 12 is -1V), the equivalent topography of the curved micro-lens 101 formed thereby is shown as the dashed line L2. The 1-n2 voltage signals of the second electrode strips 13 are 5V, 3V, 1V, 1V, 5V in turn, the initial voltage signal of the second electrode strips 13 is 5V.

[0082] As shown in FIG. 6 and FIG. 8, relative to FIG. 1 and FIG. 6, the period of the 1-n1 voltage signals of the first electrode strips 12 is unchanged, and the period of the 1-n2 voltage signals of the second electrode strips 13 is unchanged. The initial voltage signal of the second electrode strips 13 is translated by a first distance along the first direction, the initial voltage signal of the second electrode strips 13 is changed from 5V to 3V, so that the spatial potential difference distribution of the driving electric field is also translated by the first distance, and in turn, the spatial distribution pattern of the liquid crystal molecule deflection angle is also translated by the first distance. As can be seen from FIG. 7 and FIG. 8, the equivalent topography of the curved micro-lens 101 is shown as the dashed line L2, which is obviously translated by the first distance along the first direction relative to the equivalent topography of the curved micro-lens 101 shown as the dashed line L1.

[0083] Based on this, the method can include: translating the initial voltage signal of the m1 first electrode strips 12 from x1 to x2 along the first direction, x2>x1, the voltage signal loaded by the first electrode strip 12 satisfies the following relationship: Vx=f(x)+a, a=x2-x1; so that the position of the driving electric field is translated by a along the first direction, the driving electric field after translation drives the liquid crystal micro-lens array 1 to be translated by a along the first direction. The initial voltage signal of the m second electrode strips 13 can also be translated from y1 to y2 along the second direction, y2>y1, the voltage signal loaded by the second electrode strip 13 satisfies the following relationship: Vy=-g(y)+b, b=y2-y1; so that the position of the driving electric field is translated by b along the second direction, the driving electric field after translation drives the liquid crystal micro-lens array 1 to be translated by b along the second direction.

[0084] Therefore, the starting voltage signal of the m1 first electrode strips 12 can be translated a in the first direction as needed, so that the equivalent topography of the curved micro-lens 101 is translated a in the first direction. Or the starting voltage signal of the m2 second electrode strips 13 can be translated b in the second direction, so that the equivalent topography of the curved micro-lens 101 is translated b in the second direction. The starting voltage signal of the m1 first electrode strips 12 can also be translated a in the first direction, and the starting voltage signal of the m2 second electrode strips 13 can be translated b in the second direction at the same time, so that the equivalent topography of the curved micro-lens 101 is translated a in the first direction and b in the second direction at the same time.

[0085] As shown in FIG. 7 and FIG. 9, the method can further include reducing the voltage signal input by the first electrode strips 12 to reduce the strength of the driving electric field, and since the driving electric field becomes smaller, the rotation angle of the liquid crystal molecules driven by the driving electric field becomes smaller, resulting in a smaller arch height and a larger curvature radius of the curved micro-lens 101, thereby resulting in a smaller focal length of the curved micro-lens 101. The voltage signals of the 1-n2 second electrode strips 13 change from 5V, 3V, 1V, 1V, 5V to 3V, 1.5V, 0V, 1.5V, 3V, and the arch height of the equivalent topography of the curved micro-lens 101 changes from 10, 8, 6, 8, 10 to 8, 6.5, 5, 6.5, 8.

[0086] The principle of reducing the voltage signal input by the first electrode strips 12 can also be applied to reducing the voltage signal input by the second electrode strips 13, and the same effect of reducing the focal length of the curved micro-lens 101 can be achieved. Of course, the voltage signal input by the first electrode strips 12 can also be increased, or the voltage signal input by the second electrode strips 13 can also be increased, or the voltage signal input by the first electrode strips 12 and the voltage signal input by the second electrode strips 13 can be increased at the same time, to increase the focal length of the curved micro-lens 101.

[0087] The method can further include reducing the period n1 of the voltage signal of the first electrode strips 12, or reducing the period n2 of the voltage signal of the second electrode strips 13, or reducing the period n1 of the voltage signal of the first electrode strips 12 and the period n2 of the voltage signal of the second electrode strips 13 at the same time, to reduce the diameter of the driving electric field, and further reduce the diameter of the curved micro-lens 101. As shown in FIG. 7 and FIG. 10, the period n2 of the voltage signal of the second electrode strips 13 changes from 5V, 3V, 1V, 3V, 5V to 5V, 1V, 5V, and the diameter of the curved micro-lens 101 changes from 4pitch to 2pitch. The period n1 of the voltage signal of the first electrode strips 12 can also be increased, or the period n2 of the voltage signal of the second electrode strips 13 can also be increased, or the period n1 of the voltage signal of the first electrode strips 12 and the period n2 of the voltage signal of the second electrode strips 13 can be increased at the same time, to increase the diameter of the driving electric field, and further increase the diameter of the curved micro-lens 101. 2， The period n1 of the voltage signal of the first electrode strips 12 can also be increased, or the period n2 of the voltage signal of the second electrode strips 13 can also be increased, or the period n1 of the voltage signal of the first electrode strips 12 and the period n2 of the voltage signal of the second electrode strips 13 can be increased at the same time, to increase the diameter of the driving electric field, and further increase the diameter of the curved micro-lens 101.

[0088] It should be noted that the first direction is the x direction in FIG. 1, FIG. 2, FIG. 3, FIG. 5 and FIG. 6, and the second direction is the y direction in FIG. 1, FIG. 2, FIG. 3, FIG. 5 and FIG. 6.

[0089] The embodiment of the present application also provides a near-eye display system. As shown in FIG. 11 to FIG. 15, the near-eye display system comprises the display panel 2 and the liquid crystal microlens array 1 provided in any one of the above, the liquid crystal microlens array 1 is arranged on the display side of the display panel 2, and the liquid crystal microlens array 1 is parallel to the display panel 2.

[0090] The aperture of the curved microlens 101 satisfies the formula: Sh x n t / L≤D≤S x n t ;

[0091] The focal length of the curved microlens 101 satisfies the formula: 1 / f = 1 / (h x n t )-1 / H;

[0092] The radius of curvature of the curved microlens 101 satisfies the formula: r = f(n e -n o );

[0093] The camber height of the curved microlens 101 is:

[0094] Wherein, D is the aperture of the curved microlens 101, S is the maximum diameter of the pupil, L is the distance between the eyeball and the curved microlens 101, h is the distance between the display panel 2 and the curved microlens 101, n t is the refractive index of the medium between the display panel 2 and the liquid crystal microlens array 1, f is the focal length of the curved microlens 101, n o is the refractive index of the ordinary light of the liquid crystal, n e is the refractive index of the extraordinary light of the liquid crystal, f is the focal length of the curved microlens 101, and r is the radius of curvature of the curved microlens 101.

[0095] As shown in FIG. 11, the focal length of the liquid crystal microlens array 1 can be changed by adjusting the voltage signal of the first electrode and the second electrode, the imaging position can be changed by changing the focal length of the liquid crystal microlens array 1, and the observer can feel the change of the near and far of the imaging through the single eye. According to the left and right eye image, the depth of field of the near-eye display system is adjusted, so that the “appropriate” focal length considered by the brain matches the actual focal length perceived by the single eye, and the internal consumption is reduced or eliminated.

[0096] As shown in FIG. 12 and FIG. 13, by reducing the period n1 of the voltage signal of the first electrode and / or the period n2 of the voltage signal of the second electrode, the aperture of the curved microlens 101 can be reduced, and the definition of the near-eye display system can be improved.

[0097] It should be noted that the maximum diameter of the pupil S is generally 3-4 mm, and the medium between the display panel 2 and the liquid crystal microlens array 1 is generally glass, and the refractive index of the glass is generally about 1.5.

[0098] As shown in FIG. 14, the near-eye display system can further include a magnifying lens 3, which is disposed on the side of the liquid crystal microlens array 1 away from the display panel 2 and close to the eyeball, and the magnifying lens 3 is parallel to the liquid crystal microlens array 1. By adjusting the focal length of the liquid crystal microlens array 1 in real time, the depth of field of the near-eye display system can be adjusted. The magnifying lens 3 can increase the field of view (FOV), and the larger the field of view, the more comprehensive the image seen.

[0099] As shown in FIG. 15, the near-eye display system can further include a free-form surface mirror 4, and the display panel 2 and the liquid crystal microlens array 1 are disposed obliquely between the free-form surface mirror 4 and the eyeball, and the free-form surface mirror 4 is located on the emergent light of the liquid crystal microlens array 1, and the emergent light is reflected to the eyeball by the microlens array. Similarly, by adjusting the focal length of the liquid crystal microlens array 1 in real time, the depth of field of the near-eye display system can be adjusted. The free-form surface mirror 4 can reduce the distance between the display panel 2 and the liquid crystal microlens array 1, and thus reduce the thickness of the near-eye display system.

[0100] Other embodiments of the application will be apparent to those skilled in the art from consideration of the specification and practice of the application disclosed herein. It is intended that the specification and examples be considered as exemplary only, with the true scope and spirit of the application being indicated by the following claims.

Claims

1. A liquid crystal microlens array, wherein, The application relates to a liquid crystal cell, comprising: a liquid crystal layer, a first substrate and a second substrate, the liquid crystal layer having a first surface and a second surface arranged oppositely, the first substrate being arranged on the first surface of the liquid crystal layer, and the second substrate being arranged on the second surface of the liquid crystal layer; m1 first electrode strips arranged on the side of the first substrate close to the liquid crystal layer, the first electrode strips extending along a first direction, a plurality of the first electrode strips being arranged along a second direction, the m1 first electrode strips comprising at least one group of first electrode strips, each group of the first electrode strips comprising n1 first electrode strips; m2 second electrode strips arranged on the side of the second substrate close to the liquid crystal layer, the second electrode strips extending along the second direction, a plurality of the second electrode strips being arranged along the first direction, the m2 second electrode strips comprising at least one group of second electrode strips, each group of the second electrode strips comprising n2 second electrode strips; the angle between the second direction and the first direction being greater than 0 degrees and less than 180 degrees, and the orthographic projection of each second electrode strip on the first substrate intersecting the orthographic projection of each first electrode strip on the first substrate; each group of the first electrode strips being respectively given 1-n1 voltage signals, each group of the second electrode strips being respectively given 1-n2 voltage signals, and a curved surface microlens being formed at each n1*n2 intersection point, 2<=n1<=m1, and 2<=n2<=m2. The m1 first electrode strips comprise at least two groups of first electrode strips, the m2 second electrode strips comprise at least two groups of second electrode strips, and at least four curved surface microlenses are formed at m1*m2 intersection points by controlling the voltage values of the voltage signals. The distance between adjacent two first electrode strips is the same as the distance between adjacent two second electrode strips, when n1=n2, the component of the distance from the center to the edge of the orthographic projection of the curved surface microlens on the first substrate on the first direction is equal to the component on the second direction, the distance between adjacent first electrode strips is equal to the distance between adjacent second electrode strips and is a first distance, and the distance from the center to the edge of the orthographic projection of the curved surface microlens on the first substrate is D=n1*pitch, pitch being the size of the first distance. The distance between adjacent two first electrode strips is different from the distance between adjacent two second electrode strips, when n1=n2, when the distance between the first electrode strips is greater than the distance between adjacent two second electrode strips, the component of the distance from the center to the edge of the orthographic projection of the curved surface microlens on the first substrate on the first direction is less than the component on the second direction, and when the distance between the first electrode strips is less than the distance between adjacent two second electrode strips, the component of the distance from the center to the edge of the orthographic projection of the curved surface microlens on the first substrate on the first direction is greater than the component on the second direction. ​ ​ 2. The liquid crystal microlens array according to claim 1, wherein ​ 3. The liquid crystal microlens array according to claim 1, wherein ​ 4. The liquid crystal microlens array according to claim 1, wherein, ​ 5. The liquid crystal microlens array according to claim 1, wherein, m1 first electrode strips are connected to 1-n1 voltage signals, m2 second electrode strips are connected to 1-n2 voltage signals, when n1 is greater than n2, the component of the distance from the center to the edge of the orthographic projection of the curved microlens on the first substrate in the first direction is less than that in the second direction, when n1 is less than n2, the component of the distance from the center to the edge of the orthographic projection of the curved microlens on the first substrate in the first direction is greater than that in the second direction.

6. The liquid crystal microlens array according to claim 1, wherein The number of each group of the first electrode strips is greater than or equal to 10, the number of each group of the second electrode strips is greater than or equal to 10, and the distance from the center to the edge of the orthographic projection of the curved microlens on the first substrate is 100-2000 μm.

7. The liquid crystal microlens array according to claim 1, wherein The angle between the second direction and the first direction is greater than 45 degrees and less than 135 degrees.

8. A method of driving the liquid crystal microlens array as claimed in any one of claims 1 to 7, wherein, The method comprises: m1 first electrode strips are connected to 1-n1 voltage signals, m2 second electrode strips are connected to 1-n2 voltage signals, and at least one curved microlens is formed at the m1*m2 intersection points, 2≤n1≤m1, 2≤n2≤m2.

9. The driving method of the liquid crystal microlens array according to claim 8, wherein, The voltage signal loaded on the first electrode strip satisfies the following relationship: Vx=f(x), x is the coordinate of the first electrode strip along the first direction, and Vx is the input potential of the first electrode strip at the position; The voltage signal loaded on the second electrode strip satisfies the following relationship: Vy=-g(y), y is the coordinate of the first electrode strip along the second direction, and Vy is the input potential of the second electrode strip at the position; The potential difference of any point (x, y) in the liquid crystal cell is: ΔV=f(x)-(-g(y))=f(x)+g(y).

10. The method of driving a liquid crystal lens array according to claim 9, wherein, f(x) = x 2 , g(y) = y 2 , the potential difference of any point (x, y) in the liquid crystal cell is: ΔV = x 2 + y 2 .

11. The method of driving a liquid crystal lens array according to claim 9, wherein, The method further comprises: The starting voltage signal of the m1 first electrode strips is translated from x1 to x2 along the first direction, x2>x1, and the voltage signal loaded on the first electrode strip satisfies the following relationship: Vx=f(x)+a, a=x2-x1; And / or the starting voltage signal of the m2 second electrode strips is translated from y1 to y2 along the second direction, y2>y1, and the voltage signal loaded on the second electrode strip satisfies the following relationship: Vy=-g(y)+b, b=y2-y1; So that each curved microlens is translated by a along the first direction and / or by b along the second direction.

12. The driving method of the liquid crystal microlens array according to claim 8, wherein The method further comprises: The voltage signal input by the first electrode strip is reduced, and / or the voltage signal input by the second electrode strip is reduced, to reduce the arch height of the curved microlens; the voltage signal input by the first electrode strip is increased, and / or the voltage signal input by the second electrode strip is increased, to increase the arch height of the curved microlens.

13. The driving method of the liquid crystal microlens array according to claim 8, wherein The method further comprises: The period n1 of the voltage signal of the first electrode strip is reduced and / or the period n2 of the voltage signal of the second electrode strip is reduced, to reduce the diameter of the curved microlens; or the period n1 of the voltage signal of the first electrode strip is increased and / or the period n2 of the voltage signal of the second electrode strip is increased, to increase the diameter of the curved microlens.

14. A near-eye display system, wherein, It comprises: A display panel; The liquid crystal microlens array of any one of claims 1 to 7 is arranged on a display side of the display panel, and the liquid crystal microlens array and the display panel are parallel to each other; The aperture of the curved microlens satisfies the formula: Sh x n t / L≤D≤S x n t ; The focal length of the curved microlens satisfies the formula: 1 / f = 1 / (h x n t )-1 / H; The curvature radius of the curved microlens satisfies the formula: r = f(n e -n o ); The camber height of the curved microlens is: Wherein, D is the aperture of the curved microlens, S is the maximum diameter of the pupil, L is the distance between the eyeball and the curved microlens, h is the distance between the display panel and the curved microlens, H is the distance between the imaging position and the curved microlens, nt is the refractive index of the medium between the display panel and the liquid crystal microlens array, f is the focal length of the curved microlens, no is the refractive index of the liquid crystal to ordinary light, ne is the refractive index of the liquid crystal to extraordinary light, f is the focal length of the curved microlens, and r is the radius of curvature of the curved microlens.

15. The near-eye display system of claim 14, wherein, The near-eye display system further comprises a magnifying lens, which is arranged on a side of the liquid crystal microlens array away from the display panel and close to the eyeball, and the magnifying lens and the liquid crystal microlens array are parallel to each other.

16. The near-eye display system of claim 14, wherein, The near-eye display system further comprises a free-form reflective mirror, and the display panel and the liquid crystal microlens array are arranged obliquely between the free-form reflective mirror and the eyeball, the free-form reflective mirror is located on the emergent light ray of the liquid crystal microlens array, and the emergent light ray is reflected to the eyeball by the microlens array.

Images