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

Abstract

A liquid crystal microlens array includes m1 first electrode bars and m2 second electrode bars. The orthographic projections of the second electrode bars on the liquid crystal layer intersect the orthographic projections of the first electrode bars on the liquid crystal layer respectively. The m1 first electrode bars are respectively fed with 1-n1 voltage signals, and the m2 second electrode bars are respectively fed with 1-n2 voltage signals. By controlling the voltage values of the voltage signals, the rotation angle of the liquid crystal molecules at this position in the liquid crystal cell can be changed to form an annular phase delay distribution, so as to form a curved microlens at each n1×n2 intersection point. The first electrode bars and the second electrode bars are in a strip structure, which is relatively simple to manufacture. By controlling the sizes of n1 and n2, the shape and size of the curved microlens can be controlled, and the regulation accuracy is relatively high. A driving method for the liquid crystal microlens array and a near-eye display system including the liquid crystal microlens array are also provided.

Description

Technical Field

[0001] The present invention relates to the field of display technologies, and in particular, to a liquid crystal microlens array, a driving method thereof, and a near-eye display system. Background Art

[0002] In near-eye display technologies, the images received by each of the left and right eyes can only be planar images, and their 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, thereby causing serious internal consumption.

[0003] Therefore, liquid crystal microlenses are introduced. By adjusting the focal length of the liquid crystal microlenses, the imaging position is changed, enabling the observer to feel the change in the distance of the imaging through a single eye. Currently, the structure of the liquid crystal microlens array is complex to fabricate and the regulation accuracy is not high.

[0004] It should be noted that the information of the invention in the above background art is only used to enhance the understanding of the background of the present invention, and thus may include information that does not constitute the prior art known to those of ordinary skill in the art. Summary of the Invention

[0005] The purpose of the present invention is to overcome the problems that the current structure of the liquid crystal microlens array is complex to fabricate and the regulation accuracy is not high, and to provide a liquid crystal microlens array, a driving method thereof, and a near-eye display system.

[0006] According to one aspect of the present invention, a liquid crystal microlens array is provided. The liquid crystal microlens array includes a liquid crystal cell, m1 first electrode strips, and m2 second electrode strips. The liquid crystal cell includes a liquid crystal layer, a first substrate, and a second substrate. The liquid crystal layer has a first surface and a second surface disposed opposite to each other. The first substrate is disposed on the first surface of the liquid crystal layer, and the second substrate is disposed on the second surface of the liquid crystal layer. The m1 first electrode strips are disposed on the side of the first substrate close to the liquid crystal layer. The first electrode strips extend along a first direction, and a plurality of first electrode strips are arranged along a second direction. The m1 first electrode strips include at least one group of first electrode strips, and each group of first electrode strips includes n1 first electrode strips. The m2 second electrode strips are disposed on the side of the second substrate close to the liquid crystal layer. The second electrode strips extend along the second direction, and a plurality of second electrode strips are arranged along the first direction. The m2 second electrode strips include at least one group of second electrode strips, and each group of second electrode strips includes n2 second electrode strips. The angle between the second direction and the first direction is greater than 45 degrees and less than 135 degrees. The orthographic projections of the second electrode strips on the first substrate respectively intersect with the orthographic projections of the first electrode strips on the first substrate. Each group of first electrode strips is respectively input with 1 - n1 voltage signals, and each group of second electrode strips is respectively input with 1 - n2 voltage signals. A curved microlens is formed at each of the n1×n2 intersections, where 2≤n1≤m1 and 2≤n2≤m2.

[0007] In one embodiment of the present invention, m1 first electrode strips include at least two groups of first electrode strips, and m2 second electrode strips include at least two groups of second electrode strips. By controlling the voltage values of each voltage signal, at least four curved microlenses are formed at the m1×m2 intersections.

[0008] In one embodiment of the present invention, the distance between adjacent first electrode strips is the same as the distance between adjacent second electrode strips. When n1 = 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 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 both a first distance. The distance from the center to the edge of the orthographic projection of the curved microlens on the first substrate is: D = n1×pitch, where pitch is the magnitude of the first distance.

[0009] In one embodiment of the present invention, the distance between adjacent first electrode strips is different from the distance between adjacent second electrode strips. When n1 = n2, when the distance between the first electrode strips is greater than the distance between adjacent second electrode strips, 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 the component in the second direction. When the distance between the first electrode strips is less than the distance between adjacent second electrode strips, the component of the distance from the center to the edge of the orthographic projection of the curved microlens formed at the n1×n2 intersections on the first substrate in the first direction is greater than the component in the second direction.

[0010] In one embodiment of the present invention, m1 first electrode strips are fed with 1 - n1 voltage signals, and m2 second electrode strips are fed 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 microlens on the first substrate in the first direction is less than the component 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 the component in the second direction.

[0011] In one embodiment of the present invention, the number of first electrode strips in each group is greater than or equal to 10, and the number of second electrode strips in each group is greater than or equal to 10. The distance from the center to the edge of the orthographic projection of the surface microlens on the first substrate is 100μm - 2000μm.

[0012] In one embodiment of the present invention, the angle between the second direction and the first direction is greater than 45 degrees and less than 135 degrees.

[0013] According to another aspect of the present invention, there is provided a driving method for a liquid crystal microlens array provided in one aspect of the present invention, the method comprising: respectively applying 1 - n1 voltage signals to m1 first electrode strips, and respectively applying 1 - n2 voltage signals to m2 second electrode strips, and forming at least one curved microlens at m1×m2 intersections, where 2≤n1≤m1 and 2≤n2≤m2.

[0014] In an embodiment of the present invention, the first electrode strip and the voltage signal applied thereto satisfy the following relationship: Vx = f(x), where x is the coordinate of the first electrode strip along the first direction, and Vx is the input electric potential of the first electrode strip at this position; the second electrode strip and the voltage signal applied thereto satisfy the following relationship: Vy = -g(y), where y is the coordinate of the first electrode strip along the second direction, and Vy is the input electric potential of the second electrode strip at this position; the potential difference at any point (x, y) in the liquid crystal cell is: △V = f(x) - (-g(y)) = f(x) + g(y).

[0015] In an embodiment of the present invention, f(x) = x 2 , g(y) = y 2 , and the potential difference at any point (x, y) in the liquid crystal cell is: △V = x 2 + y 2 .

[0016] In an embodiment of the present invention, the method further comprises: translating the starting voltage signal of the m1 first electrode strips along the first direction from x1 to x2, where x2 > x1, and the first electrode strip and the voltage signal applied thereto satisfy the following relationship: Vx = f(x) + a, where a = x2 - x1; and / or translating the starting voltage signal of the m2 second electrode strips along the second direction from y1 to y2, where y2 > y1, and the second electrode strip and the voltage signal applied thereto satisfy the following relationship: Vy = -g(y) + b, where b = y2 - y1; so that each curved microlens array is translated by a along the first direction and / or by b along the second direction.

[0017] In an embodiment of the present invention, the method further comprises: reducing the voltage signal input to the first electrode strip, and / or reducing the voltage signal input to the second electrode strip, to reduce the arch height of the curved microlens; increasing the voltage signal input to the first electrode strip, and / or increasing the voltage signal input to the second electrode strip, to increase the arch height of the curved microlens.

[0018] In an embodiment of the present invention, the method further comprises: reducing the period n1 of the voltage signal of the first electrode strip and / or reducing the period n2 of the voltage signal of the second electrode strip, to reduce the diameter of the curved microlens; or increasing the period n1 of the voltage signal of the first electrode strip and / or increasing the period n2 of the voltage signal of the second electrode strip, to increase the diameter of the curved microlens.

[0019] According to another aspect of the present invention, a near-eye display system is provided, including a display panel and the liquid crystal microlens array provided by one aspect of the present invention. The liquid crystal microlens array is disposed on the display side of the display panel, and the liquid crystal microlens array is parallel to the display panel;

[0020] The aperture of the curved microlens satisfies the formula: Sh×n t / L ≤ D ≤ S×n t ;

[0021] The focal length of the curved microlens satisfies the formula: 1 / f = 1 / (h×n t ) - 1 / H;

[0022] The radius of curvature of the curved microlens satisfies the formula: r = f(n e - n o );

[0023] The arch height of the curved microlens is:

[0024] 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, n t 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, n o is the refractive index of the liquid crystal for ordinary light, n e is the refractive index of the liquid crystal for extraordinary light, f is the focal length of the curved microlens, and r is the radius of curvature of the curved microlens.

[0025] In an embodiment of the present invention, the near-eye display system further includes a magnifying lens. The magnifying lens is disposed on the side of the liquid crystal microlens array away from the display panel and close to the eyeball, and the magnifying lens is parallel to the liquid crystal microlens array.

[0026] In an embodiment of the present invention, the near-eye display system further includes a free-form surface mirror. The display panel and the liquid crystal microlens array are inclined between the free-form surface mirror and the eyeball. The free-form surface mirror is located on the outgoing light ray of the liquid crystal microlens array, and the outgoing light ray is reflected by the microlens array to the eyeball.

[0027] The liquid crystal microlens array of the present invention includes m1 first electrode strips and m2 second electrode strips. The orthographic projections of the second electrode strips on the first substrate intersect with the orthographic projections of the first electrode strips on the first substrate respectively. The m1 first electrode strips are respectively fed with 1 - n1 voltage signals, and the m2 second electrode strips are respectively fed with 1 - n2 voltage signals. By controlling the voltage values of the voltage signals, the rotation angle of the liquid crystal molecules at this position in the liquid crystal cell can be changed to form an annular phase delay distribution, so as to form a curved microlens at each of the n1×n2 intersections. The first electrode strips and the second electrode strips are in a strip structure, which is relatively simple to manufacture. By controlling the magnitudes of n1 and n2, the shape and size of the curved microlens can be controlled, and the regulation accuracy is relatively high.

[0028] It should be understood that the above general description and the following detailed description are only exemplary and explanatory, and cannot limit the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] The drawings herein are incorporated into the specification and constitute a part of this specification, showing embodiments consistent with the present invention, and are used together with the specification to explain the principles of the present invention. Obviously, the drawings in the following description are only some embodiments of the present invention, and those of ordinary skill in the art can obtain other drawings based on these drawings without creative efforts.

[0030] Figure 1 It is a three - dimensional structural schematic diagram before the translation of the voltage signal on the second electrode strip of the liquid crystal microlens array according to the embodiment of the present invention.

[0031] Figure 2 It is a schematic diagram showing that m1 first electrode strips and m2 second electrode strips of the embodiment of the present invention overlap with each other to form m1×m2 intersections.

[0032] Figure 3 It is a schematic diagram showing the generation of potential differences at the 4 intersections formed by the overlapping of 2 first electrode strips and 2 second electrode strips according to the embodiment of the present invention.

[0033] Figure 4 It is a schematic diagram of the driving electric field according to the embodiment of the present invention.

[0034] Figure 5 It is a schematic diagram of the distribution of the annular electric potential formed by the intersection of the first electrode strip and the second electrode strip according to the embodiment of the present invention.

[0035] Figure 6 It is a three - dimensional structural schematic diagram after the translation of the voltage signal on the second electrode strip of the liquid crystal microlens array according to the embodiment of the present invention.

[0036] Figure 7Schematic cross-sectional view before voltage signal translation on the second electrode strip of the liquid crystal microlens array according to an embodiment of the present invention.

[0037] Figure 8 Schematic cross-sectional view after voltage signal translation on the second electrode strip of the liquid crystal microlens array according to an embodiment of the present invention.

[0038] Figure 9 Schematic cross-sectional view before reduction of the arch height of the equivalent morphology of the curved microlens according to an embodiment of the present invention.

[0039] Figure 10 Schematic cross-sectional view after reduction of the arch height of the equivalent morphology of the curved microlens according to an embodiment of the present invention.

[0040] Figure 11 Schematic cross-sectional view of a near-eye display system according to an embodiment of the present invention.

[0041] Figure 12 Schematic cross-sectional view before reduction of the aperture of the curved microlens of the near-eye display system according to an embodiment of the present invention.

[0042] Figure 13 Schematic cross-sectional view after reduction of the aperture of the curved microlens of the near-eye display system according to an embodiment of the present invention.

[0043] Figure 14 Schematic cross-sectional view of a near-eye display system according to an embodiment of the present invention when the near-eye display system includes a magnifying lens.

[0044] Figure 15 Schematic cross-sectional view of a near-eye display system according to an embodiment of the present invention when the near-eye display system includes a free-form surface mirror.

[0045] In the figure: 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 surface mirror, 5 - eye. Detailed implementation manners

[0046] Now, example embodiments will be described more fully with reference to the accompanying drawings. However, the example embodiments can be implemented in various forms and should not be construed as limited to the embodiments set forth herein; rather, these embodiments are provided so that this invention will be thorough and complete, and will fully convey the concept of the example embodiments to those skilled in the art. Like reference numerals in the figures denote the same or similar structures, and thus their detailed descriptions will be omitted. In addition, the drawings are only schematic illustrations of the present invention and are not necessarily drawn to scale.

[0047] Although relative terms such as "upper" and "lower" are used in this specification to describe the relative relationship of one component of an icon to another component, these terms are used in this specification only for convenience, for example, according to the directions in the examples described in the drawings. It can be understood that if the device of the icon is turned upside down, the component described as "upper" will become the component described as "lower". When a structure is "on" another structure, it may mean that a structure is integrally formed on another structure, or that a structure is "directly" disposed on another structure, or that a structure is "indirectly" disposed on another structure through another structure.

[0048] The terms "a", "an", "the", "said" and "at least one" are used to indicate the presence of one or more elements / components / etc.; the terms "comprising" and "having" are used to mean an open inclusion and mean that there may be additional elements / components / etc. in addition to the listed elements / components / etc.; the terms "first", "second", "third", etc. are used only as labels and are not a limitation on the quantity of their objects.

[0049] Virtual Reality (VR) and Augmented Reality (AR) devices belong to near-eye display systems. During near-eye display, the biggest problem faced is the vergence accommodation problem. Specifically, there are slight differences between the left-eye image and the right-eye image. After this part of the difference is analyzed by the brain, the approximate information about the distance between the viewed object and the human eye is immediately obtained. At this time, the lens of a single eye will uncontrollably make rapid adjustments to ensure that the object the human eye focuses on is accurately imaged by each eye. This is a huge advantage in the process of natural evolution, which can ensure that the eyes quickly and accurately focus after locking on an object.

[0050] However, in near-eye display systems, vergence accommodation has become a disaster. The technologies of virtual reality and augmented reality can easily project images with slight angular differences onto the left and right eyes, so as to deceive the human brain and thus generate a sense of stereoscopy. However, when the human brain receives such stereoscopic images, it will immediately send a lens adjustment instruction to adjust the lens to the "appropriate" focal length range. In the existing virtual reality and augmented reality technologies, the images received by the left and right single eyes can only be planar images, and their depth of field is fixed at a certain position in front of the eyes. As a result, the "appropriate" focal length considered by the brain does not match the actual focal length felt by the single eye, thus causing serious internal consumption.

[0051] The specific process is as follows:

[0052] 1. The brain judges that the distance between the object and the human eye is x meters based on the left-eye and right-eye images.

[0053] 2. The brain sends instructions to the lenses of both eyes: commanding the lenses to contract or relax, so that the focal length is adjusted to x meters.

[0054] 3. The focal length of the lens is quickly adjusted to x meters, but the actual depth of field of a single-eye image is a fixed value of the near-eye display system (assumed to be y meters), and x≠y, resulting in blurred retinal imaging.

[0055] 4. The brain finds that the image is blurred and commands the lens to adjust again. Finally, when the focal length is adjusted to y meters, the image becomes clear.

[0056] 5. The brain commands the lens to adjust to the focal length of x meters again according to the binocular parallax. This cycle repeats. This internal consumption will not only cause the ciliary muscle to be fatigued in regulation, but also greatly consume the energy of the human brain, making people feel fatigued, dizzy, and overused, which greatly limits the application of virtual reality and augmented reality technologies.

[0057] Therefore, a liquid crystal microlens array 1 is introduced into the near-eye display system. The liquid crystal microlens array 1 may include a liquid crystal cell 11, a first electrode, and a second electrode. The liquid crystal cell 11 may include a first substrate 111, a second substrate 112, and a liquid crystal layer. The first electrode and the second electrode may be disposed on one 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 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 at this position of the liquid crystal layer, forming the liquid crystal microlens array 1. The liquid crystal microlens array 1 is disposed 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, so that the observer can feel the change in the distance of the image through a single eye. The depth of field of the near-eye display system is adjusted according to the left and right eye images, so that the "suitable" focal length considered by the brain matches the actual focal length felt by a single eye. However, most liquid crystal microlens arrays 1 need to adopt annular first electrodes and second electrodes, and this structure is complex to manufacture and has low regulation accuracy.

[0058] Based on this, an embodiment of the present invention provides a liquid crystal microlens array 1. As Figures 1 to 15As shown in the figure, the liquid crystal microlens array 1 includes a liquid crystal cell 11, m1 first electrode bars 12, and m2 second electrode bars 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 surface and a second surface disposed opposite to each other. The first substrate 111 is disposed on the first surface of the liquid crystal layer, and the second substrate 112 is disposed on the second surface of the liquid crystal layer. The m1 first electrode bars 12 are disposed on the side of the first substrate 111 close to the liquid crystal layer. The first electrode bars 12 extend along a first direction, and a plurality of first electrode bars 12 are arranged along a second direction. The m1 first electrode bars 12 include at least one group of first electrode bars 12, and each group of first electrode bars 12 includes n1 first electrode bars 12. The m2 second electrode bars 13 are disposed on the side of the second substrate 112 close to the liquid crystal layer. The second electrode bars 13 extend along the second direction, and a plurality of second electrode bars 13 are arranged along the first direction. The m2 second electrode bars 13 include at least one group of second electrode bars 13, and each group of second electrode bars 13 includes n2 second electrode bars 13. The angle between the second direction and the first direction is greater than 0 degrees and less than 180 degrees. The orthographic projections of the second electrode bars 13 on the first substrate respectively intersect with the orthographic projections of the first electrode bars 12 on the first substrate. Each group of first electrode bars 12 is respectively input with 1 - n1 voltage signals, and each group of second electrode bars 13 is respectively input with 1 - n2 voltage signals. At each of the n1×n2 intersections, a curved microlens 101 is formed along the thickness direction of the liquid crystal cell 11, where 2≤n1≤m1 and 2≤n2≤m2.

[0059] The orthographic projections of the second electrode bars 13 on the first substrate respectively intersect with the orthographic projections of the first electrode bars 12 on the first substrate. The m1 first electrode bars 12 are respectively input with 1 - n1 voltage signals, and the m2 second electrode bars 13 are respectively input with 1 - n2 voltage signals. By controlling the voltage values of the voltage signals, the rotation angle of the liquid crystal molecules at this position in the liquid crystal cell 11 can be changed, forming an annular phase delay distribution, thereby forming a curved microlens 101 at each of the n1×n2 intersections. The first electrode bars 12 and the second electrode bars 13 are bar-shaped structures, which are relatively simple to manufacture. By controlling the sizes of n1 and n2, the shape and size of the curved microlens 101 can be controlled, and the regulation accuracy is relatively high.

[0060] The following will specifically describe the liquid crystal microlens array 1 according to the embodiments of the present invention in detail.

[0061] As Figure 1As shown in the figure, the liquid crystal microlens array 1 includes a liquid crystal cell 11. 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 surface and a second surface which are oppositely arranged. The first substrate 111 is disposed on the first surface of the liquid crystal layer, and the second substrate 112 is disposed on the second surface of the liquid crystal layer. The liquid crystal microlens array 1 further includes m1 first electrode bars 12 and m2 second electrode bars 13. The m1 first electrode bars 12 are disposed on the side of the first substrate 111 close to the liquid crystal layer. The first electrode bars 12 extend along a first direction, and the multiple first electrode bars 12 are arranged along a second direction. The m2 second electrode bars 13 are disposed on the side of the second substrate 112 close to the liquid crystal layer. m1 may be equal to m2, or m1 may not be equal to m2, and no specific limitation is made here.

[0062] As Figure 2 shown, the first electrode bars 12 extend along the first direction, the m1 first electrode bars 12 are arranged along the second direction, the second electrode bars 13 extend along the second direction, the m2 second electrode bars 13 are arranged along the first direction, and the angle between the second direction and the first direction is greater than 0 degrees and less than 180 degrees. Specifically, the angle between the second direction and the first direction is greater than 45 degrees and less than 135 degrees. The orthographic projections of the respective second electrode bars 13 on the first substrate intersect the orthographic projections of the respective first electrode bars 12 on the first substrate, forming m1×m2 intersections.

[0063] The m1 first electrode bars 12 include k1 groups of first electrode bars 12, and each group of first electrode bars 12 is respectively fed with 1 - n1 voltage signals. The m2 second electrode bars 13 include k2 groups of second electrode bars 13, and each group of second electrode bars 13 is respectively fed with 1 - n2 voltage signals. m1≥k1n1, m2≥k2n2, k1≥1, k2≥1. By controlling the voltage values of the respective voltage signals, a driving electric field is formed in the liquid crystal cell 11 at every n1×n2 intersections. When k1 = k2 = 1, m1 = n1, m2 = n2, and a driving electric field as Figure 4 shown is formed at the m1×m2 intersections in the liquid crystal cell 11, and a driving electric field drives the liquid crystal molecules to form a curved microlens 101.

[0064] When k1 = k2 = k≥2, k×k driving electric fields that are periodically distributed are formed in the thickness direction of the liquid crystal cell 11 at the m1×m2 intersections, and the multiple driving electric fields drive the liquid crystal molecules to form k×k curved microlenses 101 that are periodically distributed. For example, when k = 2, 2×2 driving electric fields as Figure 4 shown are formed, and the 2×2 driving electric fields form 2×2 curved microlenses 101.

[0065] When k1≠k2, k1×k2 driving electric fields that are periodically distributed are formed at m1×m2 intersections along the thickness direction of the liquid crystal cell 11, and the multiple driving electric fields drive liquid crystal molecules to form k1×k2 curved micro-lenses 101 with a periodic distribution. For example, when k1 = 1 and k2 = 2, 1×2 driving electric fields as shown in Figure 4 are formed, and the 1×2 driving electric fields form 1×2 curved micro-lenses 101.

[0066] In this embodiment, the number of each group of first electrode strips 12 can be greater than or equal to 10, the number of each group of second electrode strips 13 can be greater than or equal to 10, and the distance from the center to the edge of the positive projection of the curved micro-lens on the first substrate is 100μm - 2000μm. 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 positive projection of the curved micro-lens on the first substrate is 100μm; 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 positive projection of the curved micro-lens on the first substrate is 300μm; 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 positive projection of the curved micro-lens on the first substrate is 2000μm.

[0067] As Figure 3 shown, when m1 = n1 = 2 and m2 = n2 = 2, the liquid crystal micro-lens array 1 can include 2 first electrode strips 12 and 2 second electrode strips 13. The 2 first electrode strips 12 extend along the first direction, the 2 second electrode strips 13 extend along the second direction, and the 2 first electrode strips 12 and the 2 second electrode strips 13 intersect respectively to form 2×2 intersections o1, o2, o3, and o4.

[0068] The magnitudes of the voltage signals of the 2 first electrode strips 12 are a and b respectively, the magnitudes of the voltage signals of the 2 second electrode strips 13 are i and j respectively, the thickness of the liquid crystal layer is d, and the electric field intensity at the intersection is determined by the potential difference between the staggered first electrode strip 12 and the second electrode strip 13. The potential difference at o1 is E1 = (a - i) / d, the potential difference at o2 is E2 = (a - j) / d, the potential difference at o3 is E3 = (b - i) / d, and the potential difference at o4 is E4 = (b - j) / d. By changing the magnitudes of the voltage signals of the first electrode strip 12 and the second electrode strip 13, a driving electric field as shown in Figure 4 is formed at n1×n2 intersections. The driving electric field drives the rotation angles of liquid crystal molecules at different positions to form a curved micro-lens 101.

[0069] When n1 = n2, the distance between adjacent first electrode strips 12 and the distance between adjacent second electrode strips 13 can be the same, driving the liquid crystal molecules to form a curved micro-lens 101. At this time, the component of the distance from the center to the edge of the positive projection of the curved micro-lens 101 formed by the driving electric field in the liquid crystal cell on the first substrate 111 in the first direction can be equal to the component in the second direction.

[0070] When n1 = n2 and the distance between adjacent first electrode strips 12 is the same as the distance between adjacent second electrode strips 13, the distance between adjacent first electrode strips 12 and the distance between adjacent second electrode strips 13 are equal and both are the first distance. The distance from the center to the edge of the positive projection of the curved micro-lens 101 on the first substrate 111 is: D = n1 × pitch, where pitch is the magnitude of the first distance.

[0071] The distance between adjacent first electrode strips 12 and the distance between adjacent second electrode strips 13 can also be different. At this time, the component of the distance from the center to the edge of the positive projection of the curved micro-lens 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 the first electrode strips 12 is greater than the distance between adjacent second electrode strips 13, the component of the distance from the center to the edge of the positive projection of the curved micro-lens 101 on the first substrate 111 in the first direction is less than the component in the second direction. When the distance between the first electrode strips 12 is less than the distance between adjacent second electrode strips 13, the component of the distance from the center to the edge of the positive projection of the curved micro-lens 101 formed at the n1×n2 intersections on the first substrate 111 in the first direction is greater than the component in the second direction.

[0072] When n1 ≠ n2, m1 first electrode strips 12 are fed with 1 - n1 voltage signals, and m2 second electrode strips 13 are fed with 1 - n2 voltage signals. At this time, the component of the distance from the center to the edge of the positive projection of the curved micro-lens 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 positive projection of the curved micro-lens 101 on the first substrate 111 in the first direction is less than the component in the second direction. When n1 is less than n2, the component of the distance from the center to the edge of the positive projection of the curved micro-lens 101 on the first substrate 111 in the first direction is greater than the component in the second direction.

[0073] In this embodiment, when n1 = n2 and the distance between adjacent first electrode strips 12 is the same as the distance between adjacent second electrode strips 13, the shape of the positive 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 positive projection of the curved microlens 101 on the first substrate 111 is the diameter of the circle. When the distance between adjacent first electrode strips 12 is different from the distance between adjacent second electrode strips 13 or n1 ≠ n2, the shape of the positive 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.

[0074] The embodiment of the present invention also provides a driving method for the liquid crystal microlens array 1. The method may include:

[0075] m1 first electrode strips 12 are respectively fed with 1 - n1 voltage signals, and m2 second electrode strips 13 are respectively fed with 1 - n2 voltage signals, and at least one driving electric field is formed in the thickness direction of the liquid crystal cell 11 at m1 × m2 intersections. At least one driving electric field drives liquid crystal molecules to form at least one curved microlens 101, where 2 ≤ n1 ≤ m1 and 2 ≤ n2 ≤ m2.

[0076] The first electrode strip 12 and the voltage signal loaded thereon satisfy the following relationship: Vx = f(x), where x is the coordinate of the first electrode strip 12 along the first direction, and Vx is the input electric potential of the first electrode strip 12 at this position; the second electrode strip 13 and the voltage signal loaded thereon satisfy the following relationship: Vy = -g(y), where y is the coordinate of the first electrode strip 12 along the second direction, and Vy is the input electric potential of the second electrode strip 13 at this position; the potential difference at any point (x, y) of the driving electric field is: △V = f(x) - (-g(y)) = f(x) + g(y).

[0077] Assume f(x) = x 2 , g(y) = y 2 , then the potential difference at any point (x, y) of the driving electric field is: △V = x 2 + y 2 , and △V = x 2 + y 2 The function image of is exactly the three-dimensional driving electric field. It is also possible to adjust f(x) and g(y) so that the function image of △V is as close as possible to a circular driving electric field or other non-circular driving electric fields. As Figure 5 shown, n1 = n2 = 13, number m1 and m2, 1 - 13 - 1 is a cycle, and by controlling the input voltage signals of each first electrode strip 12 and each second electrode strip 13, an annular potential distribution E O can be formed, and the annular potential distribution E OThe potential difference at any point satisfies the function formula of △V = x 2 +y 2 .

[0078] The advantages of the liquid crystal microlens array 1 are as follows: It can not only adjust the focal length of the curved microlens 101, but also adjust the position of the curved microlens 101, and can also change the aperture of the curved microlens 101.

[0079] As Figure 1 and Figure 7 shown, the 1-n1 voltage signals of the first electrode strip 12 are successively: -5V, -1V, -5V. In the cross-section S1, the corresponding intersection points are all formed by one first electrode strip 12 (the voltage signal applied by this first electrode strip 12 is -5V), and the equivalent morphology of the formed curved microlens 101 is shown by the dotted line L1. In the cross-section S2, the corresponding intersection points are all formed by another first electrode strip 12 (the voltage signal applied by this first electrode strip 12 is -1V), and the equivalent morphology of the formed curved microlens 101 is shown by the dotted line L2. The 1-n2 voltage signals of the second electrode strip 13 are successively: 5V, 3V, 1V, 1V, 5V, and the starting voltage signal of the second electrode strip 13 is 5V.

[0080] As Figure 6 and Figure 8 shown, relative to Figure 1 and Figure 6 , the periods of the 1-n1 voltage signals of the first electrode strip 12 remain unchanged, and the periods of the 1-n2 voltage signals of the second electrode strip 13 remain unchanged. Translating the starting voltage signal of the second electrode strip 13 by a first distance in the first direction, the starting voltage signal of the second electrode strip 13 changes from 5V to 3V, so that the spatial potential difference distribution of the driving electric field also translates by the first distance, and then the spatial distribution pattern of the deflection angle of the liquid crystal molecules also translates by the first distance. It can be seen from Figure 7 and Figure 8 that the equivalent morphology of the curved microlens 101 as shown by the dotted line L2 is significantly translated by the first distance in the first direction relative to the equivalent morphology of the curved microlens 101 as shown by the dotted line L1.

[0081] Based on this, the method may include: translating the starting voltage signal of m1 first electrode strips 12 along a first direction from x1 to x2, where x2 > x1. The first electrode strip 12 and the voltage signal applied thereto satisfy the following relationship: Vx = f(x) + a, where a = x2 - x1; so that the position of the driving electric field is translated by a along the first direction, and the translated driving electric field drives the liquid crystal microlens array 1 to be translated by a along the first direction. Alternatively, the starting voltage signal of m second electrode strips 13 may be translated along a second direction from y1 to y2, where y2 > y1. The second electrode strip 13 and the voltage signal applied thereto satisfy the following relationship: Vy = -g(y) + b, where b = y2 - y1; so that the position of the driving electric field is translated by b along the second direction, and the translated driving electric field drives the liquid crystal microlens array 1 to be translated by b along the second direction.

[0082] Therefore, as needed, the starting voltage signal of m1 first electrode strips 12 can be translated by a along the first direction, so that the equivalent morphology of the curved microlens 101 is translated by a along the first direction. Or the starting voltage signal of m2 second electrode strips 13 can be translated by b along the second direction, so that the equivalent morphology of the curved microlens 101 is translated by b along the second direction. It is also possible to translate the starting voltage signal of m1 first electrode strips 12 by a along the first direction while translating the starting voltage signal of m2 second electrode strips 13 by b along the second direction, so that the equivalent morphology of the curved microlens 101 is translated by a along the first direction and by b along the second direction simultaneously.

[0083] As Figure 7 and Figure 9 shown, the method may further include: reducing the voltage signal input to the first electrode strip 12 to reduce the intensity of the driving electric field. 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 microlens 101, thereby causing a smaller focal length of the curved microlens 101. The voltage signals of 1 - n2 of the second electrode strip 13 change from 5V, 3V, 1V, 1V, 5V to 3V, 1.5V, 0V, 1.5V, 3V, and the corresponding arch heights of the equivalent morphology of the curved microlens 101 change from 10, 8, 6, 8, 10 to 8, 6.5, 5, 6.5, 8.

[0084] Based on the principle of reducing the voltage signal input to the first electrode strip 12, the voltage signal input to the second electrode strip 13 can also be reduced, and the same effect of reducing the focal length of the curved microlens 101 can be achieved. Of course, the voltage signal input to the first electrode strip 12 can also be increased, or the voltage signal input to the second electrode strip 13 can be increased, or the voltage signals input to the first electrode strip 12 and the second electrode strip 13 can be increased simultaneously to increase the focal length of the curved microlens 101.

[0085] The method may further include: reducing the period n1 of the voltage signal of the first electrode strip 12, or reducing the period n2 of the voltage signal of the second electrode strip 13, or simultaneously reducing the period n1 of the voltage signal of the first electrode strip 12 and the period n2 of the voltage signal of the second electrode strip 13, so as to reduce the diameter of the driving electric field, and further reduce the diameter of the curved microlens 101. As Figure 7 and Figure 10 shown, when the period n2 of the voltage signal of the second electrode strip 13 changes from 5V, 3V, 1V, 3V, 5V to 5V, 1V, 5V, the diameter of the curved microlens 101 changes from 4 pitch to 2 pitch. The period n1 of the voltage signal of the first electrode strip 12 can be increased, the period n2 of the voltage signal of the second electrode strip 13 can be increased, or the period n1 of the voltage signal of the first electrode strip 12 and the period n2 of the voltage signal of the second electrode strip 13 can be simultaneously increased, so as to increase the diameter of the driving electric field, and further increase the diameter of the curved microlens 101.

[0086] It should be noted that the first direction is the Figure 1 、 Figure 2 、 Figure 3 、 Figure 5 and Figure 6 x-direction in Figure 1 、 Figure 2 、 Figure 3 、 Figure 5 and Figure 6 , and the second direction is the

[0087] Embodiment of the present invention further provides a near-eye display system. As Figures 11 to 15 shown, the near-eye display system includes a 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.

[0088] The aperture of the curved microlens 101 satisfies the formula: Sh×n t / L ≤ D ≤ S×n t ;

[0089] The focal length of the curved microlens 101 satisfies the formula: 1 / f = 1 / (h×n t ) - 1 / H;

[0090] The radius of curvature of the curved microlens 101 satisfies the formula: r = f(n e - n o );

[0091] The arch height of the curved microlens 101 is:

[0092] 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 liquid crystal for ordinary light, n e is the refractive index of the liquid crystal for extraordinary light, f is the focal length of the curved microlens 101, and r is the radius of curvature of the curved microlens 101.

[0093] As Figure 11 shown, by adjusting the voltage signals of the first electrode and the second electrode, the focal length of the liquid crystal microlens array 1 can be changed. By changing the focal length of the liquid crystal microlens array 1, the imaging position can be changed, enabling the observer to feel the change in the distance of the image through a single eye. By adjusting the depth of field of the near-eye display system according to the left and right eye images, the "appropriate" focal length considered by the brain is matched with the actual focal length felt by the single eye, reducing or eliminating the internal consumption.

[0094] As Figure 12 and Figure 13 shown, 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, improving the clarity of the near-eye display system.

[0095] It should be noted that the maximum diameter S of the pupil 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 glass is usually about 1.5.

[0096] As Figure 14 shown, the near-eye display system may further include a magnifying lens 3. The magnifying lens 3 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 adjustment of the depth of field of the near-eye display system can be achieved. The magnifying lens 3 can increase the field of view (Field of View, FOV), and the larger the field of view, the more comprehensive the image seen.

[0097] As Figure 15As shown, the near-eye display system may further include a free-form surface mirror 4. The display panel 2 and the liquid crystal microlens array 1 are inclined between the free-form surface mirror 4 and the eyeball. The free-form surface mirror 4 is located on the outgoing light path of the liquid crystal microlens array 1, and the outgoing light is reflected by the microlens array to the eyeball. 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 setting of the free-form surface mirror 4 can reduce the distance between the display panel 2 and the liquid crystal microlens array 1, thereby reducing the thickness of the near-eye display system.

[0098] Those skilled in the art will readily conceive of other embodiments of the present invention after considering the specification and practicing the invention herein. This application is intended to cover any variations, uses, or adaptations of the present invention that follow the general principles of the present invention and include known common knowledge or conventional technical means in the technical field not invented by the present invention. The specification and examples are only regarded as exemplary, and the true scope and spirit of the present invention are pointed out by the appended claims.

Claims

1. A liquid crystal microlens array, characterized in that, Comprising: A liquid crystal cell, including a liquid crystal layer, a first substrate, and a second substrate. The liquid crystal layer has a first surface and a second surface disposed opposite to each other. The first substrate is disposed on the first surface of the liquid crystal layer, and the second substrate is disposed on the second surface of the liquid crystal layer; m1 first electrode strips, disposed on the side of the first substrate close to the liquid crystal layer. The first electrode strips extend along a first direction, and a plurality of the first electrode strips are arranged along a second direction. The m1 first electrode strips include at least one group of first electrode strips, and each group of the first electrode strips includes n1 first electrode strips; m2 second electrode strips, disposed on the side of the second substrate close to the liquid crystal layer. The second electrode strips extend along the second direction, and a plurality of the second electrode strips are arranged along the first direction. The m2 second electrode strips include at least one group of second electrode strips, and each group of the second electrode strips includes n2 second electrode strips; The included angle between the second direction and the first direction is greater than 0 degrees and less than 180 degrees, and the orthographic projections of the second electrode strips on the first substrate and the orthographic projections of the first electrode strips on the first substrate intersect respectively; Each group of the first electrode strips is respectively fed with 1 - n1 voltage signals, and each group of the second electrode strips is respectively fed with 1 - n2 voltage signals. A curved microlens is formed at each of the n1×n2 intersections, where 2≤n1≤m1 and 2≤n2≤m2.

2. The liquid crystal microlens array according to claim 1, wherein, The m1 first electrode strips include at least two groups of first electrode strips, and the m2 second electrode strips include at least two groups of second electrode strips. By controlling the voltage values of the voltage signals, at least four curved microlenses are formed at the m1×m2 intersections.

3. The liquid crystal microlens array according to claim 1, characterized in that The distance between adjacent two of the first electrode strips is the same as the distance between adjacent two of the second electrode strips. When n1 = 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 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. The distance from the center to the edge of the orthographic projection of the curved microlens on the first substrate is: D = n1×pitch, where pitch is the magnitude of the first distance.

4. The liquid crystal microlens array according to claim 1, wherein The distance between adjacent two of the first electrode strips is different from the distance between adjacent two of the second electrode strips. When n1 = n2, when the distance between the first electrode strips is greater than the distance between adjacent two of the second electrode strips, 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 the component in the second direction. When the distance between the first electrode strips is less than the distance between adjacent two of the second electrode strips, the component of the distance from the center to the edge of the orthographic projection of the curved microlens formed at the n1×n2 intersections on the first substrate in the first direction is greater than the component in the second direction.

5. The liquid crystal microlens array according to claim 1, characterized in that, m1 first electrode strips input 1 - n1 voltage signals, and m2 second electrode strips input 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, and the number of each group of the second electrode strips is greater than or equal to 10. The distance from the center to the edge of the orthographic projection of the surface microlens on the first substrate is 100 μm - 2000 μm.

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

8. A driving method for the liquid crystal microlens array according to any one of claims 1 to 7, characterized in that, The method includes: m1 first electrode strips respectively input 1 - n1 voltage signals, and m2 second electrode strips respectively input 1 - n2 voltage signals, and at least one curved microlens is formed at m1 × m2 intersections, where 2 ≤ n1 ≤ m1 and 2 ≤ n2 ≤ m2.

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

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

11. The driving method of the liquid crystal microlens array according to claim 9, characterized in that, The method further includes: Translating the starting voltage signal of m1 first electrode strips from x1 to x2 along the first direction, where x2 > x1, and the first electrode strip and the voltage signal it loads satisfy the following relationship: Vx = f(x) + a, where a = x2 - x1; And / or translating the starting voltage signal of m2 second electrode strips from y1 to y2 along the second direction, where y2 > y1, and the second electrode strip and the voltage signal it loads satisfy the following relationship: Vy = -g(y) + b, where b = y2 - y1; So that each of the curved microlenses 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, characterized in that, The method further includes: Reducing the voltage signal input by the first electrode strip and / or reducing the voltage signal input by the second electrode strip to reduce the arch height of the curved microlens; increasing the voltage signal input by the first electrode strip and / or increasing the voltage signal input by the second electrode strip 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 includes: Reducing the period n1 of the voltage signal of the first electrode strip and / or reducing the period n2 of the voltage signal of the second electrode strip to reduce the diameter of the curved microlens; or increasing the period n1 of the voltage signal of the first electrode strip and / or increasing the period n2 of the voltage signal of the second electrode strip to increase the diameter of the curved microlens.

14. A near-eye display system, characterized in that, Includes: A display panel; The liquid crystal microlens array according to any one of claims 1 to 7 is disposed on the display side of the display panel, and the liquid crystal microlens array is parallel to the display panel; The aperture of the surface microlens satisfies the formula: Sh×n t / L ≤ D ≤ S×n t ; The focal length of the surface microlens satisfies the formula: 1 / f = 1 / (h × n t ) - 1 / H; The radius of curvature of the surface microlens satisfies the formula: r = f(n e - n o ); The sag height of the surface microlens is as follows: 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, n t 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, n o is the refractive index of the liquid crystal for ordinary light, n e is the refractive index of the liquid crystal for extraordinary light, f is the focal length of the curved microlens, r is the radius of curvature of the curved microlens.

15. The near-eye display system according to claim 14, wherein The near-eye display system further includes a magnifying lens, the magnifying lens is disposed on a side of the liquid crystal microlens array away from the display panel and close to the eyeball, and the magnifying lens is parallel to the liquid crystal microlens array.

16. The near-eye display system according to claim 14, wherein The near-eye display system further includes a free-form surface mirror, the display panel and the liquid crystal microlens array are inclined and disposed between the free-form surface mirror and the eyeball, the free-form surface mirror is located on the outgoing light ray of the liquid crystal microlens array, and the outgoing light ray is reflected by the microlens array to the eyeball.

Images