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

Abstract

A liquid crystal micro-lens array comprises m1 first electrode strips and m2 second electrode strips, the orthographic projection of each second electrode strip on a liquid crystal layer intersects with the orthographic projection of each first electrode strip on the liquid crystal layer, 1-n1 voltage signals are fed into the m1 first electrode strips respectively, 1-n2 voltage signals are fed into the m2 second electrode strips respectively, by controlling the voltage value of each voltage signal, the rotation angle of the liquid crystal molecules of the liquid crystal box at the position can be changed, annular phase delay distribution is formed, and therefore a curved surface micro lens is formed at every n1 * n2 intersection points. The first electrode strip and the second electrode strip are of a strip-shaped structure, manufacturing is simple, the size of n1 and n2 is controlled, the shape and size of the curved-surface micro lens can be controlled, and the regulation and control precision is high. The invention further provides a driving method of the liquid crystal microlens array and a near-to-eye display system comprising the liquid crystal microlens array.

Description

Technical Field

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

[0002] In near-eye display technology, the images received by the left and right eyes can only be flat 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 perceived by the eyes, resulting in serious internal friction.

[0003] 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 feel the changes in the distance of the imaging through a single eye. The current liquid crystal microlens array structure is complex to manufacture and the control accuracy is not high.

[0004] It should be noted that the information disclosed in the above background technology section is only used to enhance the understanding of the background of the present invention, and therefore may include information that does not constitute prior art known to ordinary technicians in the field. Summary of the invention

[0005] The purpose of the present invention is to overcome the problems of complex structure manufacturing and low control precision of the current liquid crystal microlens array, and to provide a liquid crystal microlens array and 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 comprising a liquid crystal box, m1 first electrode strips and m2 second electrode strips, the liquid crystal box 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 opposite to each other, 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 are arranged on a side of the first substrate close to the liquid crystal layer, the first electrode strips extend along a first direction, 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, each group of first electrode strips includes n1 first electrode strips; m2 second electrode strips are arranged on the first substrate. On the side of the second substrate close to the liquid crystal layer, the second electrode strips extend along the second direction, and the 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, and 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; 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, and a curved microlens is formed at each n1×n2 intersection, 2≤n1≤m1, 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 value of each voltage signal, at least four curved microlenses are formed at m1×m2 intersections.

[0008] In one embodiment of the present invention, the distance between two adjacent first electrode strips is the same as the distance between two 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 both are the 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 size of the first distance.

[0009] In one embodiment of the present invention, the distance between two adjacent first electrode strips is different from the distance between two adjacent second electrode strips. When n1=n2, when the distance between the first electrode strips is greater than the distance between two 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 smaller than the component in the second direction. When the distance between the first electrode strips is smaller than the distance between two 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 n1×n2 intersections on the first substrate in the first direction is larger 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 smaller 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 larger than the component in the second direction.

[0011] In one embodiment of the present invention, 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 surface microlens on the first substrate is 100 μm-2000 μm.

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

[0014] In one embodiment of the present invention, the first electrode strip and the voltage signal loaded thereon 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 potential of the first electrode strip at this position; the second electrode strip and the voltage signal loaded thereon 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 potential of the second electrode strip at this position; the potential difference at any point (x, y) in the liquid crystal box is: △V=f(x)-(-g(y))=f(x)+g(y).

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

[0016] In one embodiment of the present invention, the method also includes: translating the initial voltage signal of m1 first electrode strips from x1 to x2 along the first direction, x2>x1, and the first electrode strip and the voltage signal loaded thereon satisfy the following relationship: Vx=f(x)+a, a=x2-x1; and / or translating the initial voltage signal of m2 second electrode strips from y1 to y2 along the second direction, y2>y1, and the second electrode strip and the voltage signal loaded thereon satisfy the following relationship: Vy=-g(y)+b, 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 one embodiment of the present invention, 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, so as 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, so as to increase the arch height of the curved microlens.

[0018] In one embodiment of the present invention, 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.

[0019] According to another aspect of the present invention, there is provided a near-eye display system, comprising a display panel and a liquid crystal microlens array provided in one aspect of the present invention, wherein the liquid crystal microlens array is disposed on a display side of the display panel, and the liquid crystal microlens array and the display panel are parallel to each other;

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

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

[0024] Where 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, and n is the distance between the eyeball and the curved microlens. 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 liquid crystal for ordinary light, n e is the refractive index of 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.

[0025] In one embodiment of the present invention, the near-eye display system further comprises a magnifying lens, which 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 and the liquid crystal microlens array are parallel to each other.

[0026] In one embodiment of the present invention, the near-eye display system also includes a free-form surface reflector, the display panel and the liquid crystal microlens array are tilted between the free-form surface reflector and the eyeball, the free-form surface reflector is located on the outgoing light of the liquid crystal microlens array, and the outgoing light is reflected by the microlens array to the eyeball.

[0027] The liquid crystal microlens array of the present invention comprises m1 first electrode strips and m2 second electrode strips, the orthographic projections of each second electrode strip on the first substrate intersect with the orthographic projections of each first electrode strip on the first substrate respectively, the m1 first electrode strips are respectively fed with 1-n1 voltage signals, the m2 second electrode strips are respectively fed with 1-n2 voltage signals, and by controlling the voltage value of the voltage signal, the rotation angle of the liquid crystal molecules at the position of the liquid crystal box can be changed to form an annular phase delay distribution, thereby forming a curved surface microlens at each n1×n2 intersection. The first electrode strip and the second electrode strip are strip-shaped structures, and the manufacturing is relatively simple. By controlling the size of n1 and n2, the shape and size of the curved surface microlens can be controlled, and the regulation accuracy is relatively high.

[0028] It is to be understood that the foregoing general description and the following detailed description are exemplary and explanatory only and are not restrictive of the invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] The accompanying drawings herein are incorporated into and constitute a part of the specification, illustrate embodiments consistent with the present invention, and together with the specification are used to explain the principles of the present invention. Obviously, the accompanying drawings described below are only some embodiments of the present invention, and for those of ordinary skill in the art, other accompanying drawings can be obtained based on these accompanying drawings without creative work.

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

[0031] Figure 2 It is a schematic diagram of m1 first electrode strips and m2 second electrode strips overlapping each other to form m1×m2 intersections involved in an embodiment of the present invention.

[0032] Figure 3 It is a schematic diagram of potential differences generated at four intersections formed by overlapping two first electrode strips and two second electrode strips involved in an embodiment of the present invention.

[0033] Figure 4 It is a schematic diagram of a driving electric field involved in an embodiment of the present invention.

[0034] Figure 5 Schematic diagram of the distribution of annular potential formed by the interlacing of first electrode strips and second electrode strips involved in an embodiment of the present invention.

[0035] Figure 6 It is a schematic diagram of the three-dimensional structure after the voltage signal on the second electrode strip of the liquid crystal microlens array involved in the embodiment of the present invention is translated.

[0036] Figure 7It is a cross-sectional schematic diagram of the voltage signal on the second electrode strip of the liquid crystal microlens array involved in the embodiment of the present invention before translation.

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

[0038] Fig. 9 It is a cross-sectional schematic diagram of the equivalent morphology of the curved microlens involved in an embodiment of the present invention before the arch height is reduced.

[0039] Fig.10 It is a cross-sectional schematic diagram of the equivalent morphology of the curved microlens involved in the embodiment of the present invention after the arch height is reduced.

[0040] Fig.11 It is a cross-sectional schematic diagram of a near-eye display system according to an embodiment of the present invention.

[0041] Fig.12 It is a cross-sectional schematic diagram of a curved microlens of a near-eye display system before the aperture is reduced according to an embodiment of the present invention.

[0042] Fig.13 It is a cross-sectional schematic diagram of a curved micro-lens after the aperture is reduced according to an embodiment of the present invention related to a near-eye display system.

[0043] Fig.14 4 is a cross-sectional schematic diagram 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] Fig.15 4 is a cross-sectional schematic diagram 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 reflector.

[0045] In the figure: 1-liquid crystal microlens array, 11-liquid crystal box, 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 reflector, 5-eye. DETAILED DESCRIPTION

[0046] Example embodiments will now be described more fully with reference to the accompanying drawings. However, the example embodiments can be implemented in a variety of forms and should not be construed as limited to the embodiments set forth herein; rather, these embodiments are provided so that the present invention will be comprehensive and complete and fully convey the concepts of the example embodiments to those skilled in the art. The same reference numerals in the figures represent the same or similar structures, and thus their detailed description 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 the illustration to another component, these terms are used in this specification only for convenience, such as according to the orientation of the examples described in the drawings. It is understood that if the device of the illustration is turned upside down, the component described as "upper" will become the component "lower". When a structure is "on" other structures, it may mean that the structure is formed integrally on the other structure, or that the structure is "directly" disposed on the other structure, or that the structure is "indirectly" disposed on the other 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 "including" and "having" are used to express an open-ended inclusive meaning and mean that additional elements / components / etc. may exist in addition to the listed elements / components / etc.; the terms "first", "second" and "third" etc. are used merely as labels and are not intended to limit the quantity of their objects.

[0049] Virtual reality (VR) and augmented reality (AR) devices belong to near-eye display systems. In the near-eye display process, the biggest problem is the problem of convergence adjustment. Specifically, there is a slight difference between the left eye image and the right eye image. After the brain analyzes this difference, it immediately obtains the approximate information of the distance of the viewed object from the human eye. At this time, the lens of a single eye will adjust quickly and uncontrollably to ensure that the object that the human eye is paying attention to is accurately imaged by each eye 5. This is a huge advantage in the process of natural evolution, which can ensure that the eye 5 can focus quickly and accurately after locking on the object.

[0050] However, in near-eye display systems, convergence accommodation becomes a disaster. Virtual reality and augmented reality technologies can easily project images with slight angle differences to the left and right eyes, which can deceive the human brain and create a sense of three-dimensionality. However, when the human brain receives this stereoscopic image, it will immediately send a lens adjustment instruction 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 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, resulting in serious internal friction.

[0051] The specific process is as follows:

[0052] 1. The brain determines that the object is x meters away from the human eye based on the left and right eye images.

[0053] 2. The brain sends instructions to the lenses of both eyes: ordering 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 the monocular image is a fixed value of the near-eye display system (assuming it is y meters), x≠y, resulting in blurred retinal imaging.

[0055] 4. The brain finds that the image is blurry and instructs the lens to readjust. Finally, when the focal length is adjusted to y meters, the image becomes clear.

[0056] 5. The brain again commands the lens to adjust to a focal length of x meters based on binocular parallax. This cycle repeats. This internal friction not only causes fatigue in the ciliary muscle adjustment, but also greatly consumes the energy of the human brain, causing fatigue, dizziness, and excessive brain use, 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 box 11, a first electrode and a second electrode. The liquid crystal box 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 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 corresponding positions on both sides of the liquid crystal box 11, and a driving electric field is formed along the thickness direction of the liquid crystal box 11. The driving electric field can change the rotation angle of the liquid crystal molecules in the liquid crystal layer at this position to form a liquid crystal microlens array 1. The liquid crystal microlens array 1 is arranged on the display side of the display panel 2, and the imaging position is changed by adjusting the focal length of the liquid crystal microlens array 1, so that the observer can feel the change of the distance of the imaging 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 "appropriate" focal length considered by the brain matches the actual focal length felt by the single eye. However, most liquid crystal microlens arrays 1 require the use of an annular first electrode and a second electrode, which are complex to manufacture and have low control accuracy.

[0058] Based on this, an embodiment of the present invention provides a liquid crystal microlens array 1. Figures 1 to 15As shown, the liquid crystal microlens array 1 includes a liquid crystal box 11, m1 first electrode strips 12 and m2 second electrode strips 13. The liquid crystal box 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 arranged opposite to each other. The first substrate 111 is arranged on the first surface of the liquid crystal layer, and the second substrate 112 is arranged on the second surface of the liquid crystal layer. The m1 first electrode strips 12 are arranged on a side of the first substrate 111 close to the liquid crystal layer. The first electrode strips 12 extend along a first direction. The 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 second substrate 112 close to the liquid crystal layer. On one side of the liquid crystal layer, the second electrode strips 13 extend along the second direction, and the 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, and 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 degree and less than 180 degrees, and the orthographic projections of the second electrode strips 13 on the first substrate intersect with the orthographic projections of the first electrode strips 12 on the first substrate respectively; each group of the first electrode strips 12 is respectively fed with 1-n1 voltage signals, and each group of the second electrode strips 13 is respectively fed with 1-n2 voltage signals, and a curved microlens 101 is formed at each n1×n2 intersection along the thickness direction of the liquid crystal box 11, 2≤n1≤m1, 2≤n2≤m2.

[0059] The orthographic projections of the second electrode strips 13 on the first substrate intersect with the orthographic projections of the first electrode strips 12 on the first substrate, respectively. The m1 first electrode strips 12 are respectively fed with 1-n1 voltage signals, and the m2 second electrode strips 13 are respectively fed with 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 box 11 at that position can be changed to form an annular phase delay distribution, thereby forming a curved microlens 101 at each n1×n2 intersection. The first electrode strips 12 and the second electrode strips 13 are strip-shaped structures, which are relatively simple to manufacture. By controlling the size 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 liquid crystal microlens array 1 according to the embodiment of the present invention will be described in detail below with reference to specific examples.

[0061] like Figure 1As shown, the liquid crystal microlens array 1 includes a liquid crystal box 11, and the liquid crystal box 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 arranged opposite to each other. The first substrate 111 is arranged on the first surface of the liquid crystal layer, and the second substrate 112 is arranged on the second surface of the liquid crystal layer. The liquid crystal microlens array 1 also includes m1 first electrode strips 12 and m2 second electrode strips 13. The m1 first electrode strips 12 are arranged on a side of the first substrate 111 close to the liquid crystal layer. The first electrode strips 12 extend along the first direction, and a plurality of first electrode strips 12 are arranged along the second direction. The m2 second electrode strips 13 are arranged on a side of the second substrate 112 close to the liquid crystal layer. m1 can be equal to m2, and m1 can also be equal to m2, which is not specifically limited here.

[0062] like Figure 2 As shown, the first electrode strips 12 extend along the first direction, m1 first electrode strips 12 are arranged along the second direction, the second electrode strips 13 extend along the second direction, m2 second electrode strips 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, and 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 second electrode strips 13 on the first substrate intersect with the orthographic projections of the first electrode strips 12 on the first substrate, respectively, to form m1×m2 intersections.

[0063] The m1 first electrode strips 12 include k1 groups of first electrode strips 12, and each group of first electrode strips 12 is respectively fed with 1-n1 voltage signals, and the m2 second electrode strips 13 include k2 groups of second electrode strips 13, and each group of second electrode strips 13 is respectively fed with 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 box 11 at each n1×n2 intersection. When k1=k2=1, m1=n1, m2=n2, and the following is formed in the liquid crystal box 11 at the m1×m2 intersections: Figure 4 As shown, a driving electric field drives the liquid crystal molecules to form a curved microlens 101.

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

[0065] When k1≠k2, k1×k2 periodically distributed driving electric fields are formed at the m1×m2 intersections along the thickness direction of the liquid crystal box 11, and the multiple driving electric fields drive the liquid crystal molecules to form k1×k2 periodically distributed curved microlenses 101. For example, when k1=1, k2=2, 1×2 curved microlenses 101 are formed. Figure 4 As shown in the driving electric field, 1×2 driving electric fields form 1×2 curved microlenses 101.

[0066] In this embodiment, the number of each group of first electrode strips 12 may be greater than or equal to 10, the number of each group of second electrode strips 13 may be 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 μm-2000 μm. For example, when the number of the first electrode strips 12 is equal to 10 and the number of the second electrode strips 13 is equal to 10, the distance from the center to the edge of the orthographic projection of the curved microlens on the first substrate is 100 μm, when the number of the first electrode strips 12 is equal to 15 and the number of the second electrode strips 13 is equal to 15, the distance from the center to the edge of the orthographic projection of the curved microlens on the first substrate is 300 μm, and when the number of the first electrode strips 12 is equal to 50 and the number of the second electrode strips 13 is equal to 50, the distance from the center to the edge of the orthographic projection of the curved microlens on the first substrate is 2000 μm.

[0067] like Figure 3 As shown, when m1=n1=2 and m2=n2=2, the liquid crystal microlens array 1 may 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 with each other to form 2×2 intersection points o1, o2, o3 and o4, respectively.

[0068] The magnitudes of the voltage signals of the two first electrode strips 12 are a and b respectively, the magnitudes of the voltage signals of the two second electrode strips 13 are i and j respectively, the thickness of the liquid crystal layer is d, and the electric field strength at the intersection is determined by the potential difference between the staggered first electrode strips 12 and the second electrode strips 13. The potential difference of o1 is E1 = (ai) / d, the potential difference of o2 is E2 = (aj) / d, the potential difference of o3 is E3 = (bi) / d, and the potential difference of o4 is E4 = (bj) / d. By changing the magnitude of the voltage signal of the first electrode strip 12 and the magnitude of the voltage signal of the second electrode strip 13, an electric field such as Figure 4 The driving electric field drives the rotation angles of liquid crystal molecules at different positions to form a curved microlens 101.

[0069] When n1=n2, the distance between two adjacent first electrode strips 12 and the distance between two adjacent second electrode strips 13 can be the same, driving the liquid crystal molecules to form a curved microlens 101. At this time, 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 box on the first substrate 111 can be equal to the component in the second direction.

[0070] When n1=n2, and the distance between two adjacent first electrode strips 12 is the same as the distance between two 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 are both the first distances, and the distance from the center to the edge of the orthographic projection of the curved microlens 101 on the first substrate 111 is: D=n1×pitch, where pitch is the size of the first distance.

[0071] The distance between two adjacent first electrode strips 12 and the distance between two adjacent second electrode strips 13 may also be different. In this case, 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 formed by the driving electric field in the liquid crystal box 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 the 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 smaller than the component in the second direction. When the distance between the first electrode strips 12 is smaller than the distance between the 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 formed at n1×n2 intersections in the first direction is larger 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 distance from the center to the edge of the orthographic projection of the curved microlens 101 on the first substrate 111 formed by the driving electric field in the liquid crystal box is not equal to the distance from the center to the edge in the first direction in the second direction. When n1 is greater than n2, the distance from the center to the edge of the orthographic projection of the curved microlens 101 on the first substrate 111 is less than the distance from the center to the edge in the first direction in the second direction. When n1 is less than n2, the distance from the center to the edge of the orthographic projection of the curved microlens 101 on the first substrate 111 is greater than the distance from the center to the edge in the first direction in the second direction.

[0073] In this embodiment, when n1=n2, and the distance between two adjacent first electrode strips 12 is the same as the distance between two adjacent second electrode strips 13, the shape of the orthographic projection of the curved microlens 101 formed by the driving electric field in the liquid crystal box 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, the shape of the orthographic projection of the curved microlens 101 formed by the driving electric field in the liquid crystal box on the first substrate 111 can be elliptical.

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

[0075] The m1 first electrode strips 12 are respectively fed with 1-n1 voltage signals, and the m2 second electrode strips 13 are respectively fed with 1-n2 voltage signals, and at least one driving electric field is formed along the thickness direction of the liquid crystal box 11 at the m1×m2 intersections. The at least one driving electric field drives the liquid crystal molecules to form at least one curved microlens 101, 2≤n1≤m1, 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 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 potential of the second electrode strip 13 at this position; the potential difference at any point (x, y) in 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) in the driving electric field is: △V = x 2 +y 2 , and △V=x 2 +y 2 The function graph of △V is exactly the three-dimensional driving electric field. You can also adjust f(x) and g(y) to make the function graph of △V as circular as possible, or other non-circular driving electric field. Figure 5 As shown, n1=n2=13, m1 and m2 are numbered, 1-13-1 is a cycle, and the input voltage signal of each first electrode strip 12 and the input voltage signal of each second electrode strip 13 are controlled to form a ring potential distribution E O , annular potential distribution E OThe potential difference at any point on the 2 +y 2 The function formula of .

[0078] The advantages of the liquid crystal microlens array 1 are that it is not only possible to adjust the focal length of the curved microlens 101 , but also possible to adjust the position of the curved microlens 101 and change the aperture of the curved microlens 101 .

[0079] like Figure 1 and Figure 7 As shown, the voltage signals of the first electrode strips 12 from 1 to n1 are: -5V, -1V, -5V in sequence. In the cross section S1, the corresponding intersections are formed by one first electrode strip 12 (the voltage signal input to the first electrode strip 12 is -5V), and the equivalent morphology of the curved microlens 101 formed is shown by the dotted line L1. In the cross section S2, the corresponding intersections are formed by another first electrode strip 12 (the voltage signal input to the first electrode strip 12 is -1V), and the equivalent morphology of the curved microlens 101 formed is shown by the dotted line L2. The voltage signals of the second electrode strips 13 from 1 to n2 are: 5V, 3V, 1V, 1V, 5V in sequence, and the initial voltage signal of the second electrode strip 13 is 5V.

[0080] like Figure 6 and Figure 8 As shown, relative to Figure 1 and Figure 6 , the period of the 1-n1 voltage signal of the first electrode strip 12 remains unchanged, and the period of the 1-n2 voltage signal of the second electrode strip 13 remains unchanged. The initial voltage signal of the second electrode strip 13 is translated along the first direction by a first distance, and the initial voltage signal of the second electrode strip 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, thereby causing the spatial distribution of the deflection angle of the liquid crystal molecules to also be translated by the first distance. Figure 7 and Figure 8 It can be seen that the equivalent shape of the curved microlens 101 such as the dotted line L2 is obviously translated along the first direction by a first distance relative to the equivalent shape of the curved microlens 101 such as the dotted line L1.

[0081] Based on this, the method may include: translating the initial voltage signal of m1 first electrode strips 12 from x1 to x2 along the first direction, x2>x1, and the first electrode strips 12 and the voltage signal loaded thereon satisfy 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, and the translated driving electric field drives the liquid crystal microlens array 1 to translate by a along the first direction. The initial voltage signal of m second electrode strips 13 may also be translated from y1 to y2 along the second direction, y2>y1, and the second electrode strips 13 and the voltage signal loaded thereon satisfy 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, and the translated driving electric field drives the liquid crystal microlens array 1 to translate by b along the second direction.

[0082] Therefore, as required, the initial 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. Alternatively, the initial 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. Alternatively, the initial voltage signal of m1 first electrode strips 12 can be translated by a along the first direction, while the initial 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 a along the first direction and by b along the second direction.

[0083] like Figure 7 and Fig. 9 As shown, the method may further include: reducing the voltage signal input by the first electrode strip 12 to reduce the intensity of the driving electric field. As 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 of the curved microlens 101 and a larger curvature radius, thereby resulting in a smaller focal length of the curved microlens 101. The 1-n2 voltage signals of the second electrode strips 13 change from 5V, 3V, 1V, 1V, 5V to 3V, 1.5V, 0V, 1.5V, 3V, and the corresponding arch height of the equivalent morphology of the curved microlens 101 changes 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 by the first electrode strip 12, the voltage signal input by the second electrode strip 13 can also be reduced, and the focal length of the curved microlens 101 can also be reduced. Of course, the voltage signal input by the first electrode strip 12 can also be increased, or the voltage signal input by the second electrode strip 13 can be increased, or the voltage signal input by the first electrode strip 12 and the voltage signal input by the second electrode strip 13 can also be increased at the same time, so as 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, reducing the period n2 of the voltage signal of the second electrode strip 13, or 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 at the same time, so as to reduce the diameter of the driving electric field, thereby reducing the diameter of the curved microlens 101. Figure 7 and Fig.10 As shown, the period n2 of the voltage signal of the second electrode strip 13 is changed from 5V, 3V, 1V, 3V, 5V to 5V, 1V, 5V, and the diameter of the curved microlens 101 is changed from 4 pitches to 2 pitches. 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, and 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 increased at the same time to increase the diameter of the driving electric field, thereby increasing the diameter of the curved microlens 101.

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

[0087] The embodiment of the present invention also provides a near-eye display system. Figures 11 to 15 As shown, the near-eye display system includes a display panel 2 and a liquid crystal microlens array 1 provided in any one of the above items, the liquid crystal microlens array 1 is arranged on the display side of the display panel 2, and the liquid crystal microlens array 1 and the display panel 2 are parallel to each other.

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

[0093] like Fig.11 As shown, the focal length of the liquid crystal microlens array 1 can be changed by adjusting the voltage signals of the first electrode and the second electrode, and the imaging position can be changed by changing the focal length of the liquid crystal microlens array 1, so that the observer can feel the change of imaging distance 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 "appropriate" focal length considered by the brain matches the actual focal length felt by a single eye, reducing or eliminating internal friction.

[0094] like Fig.12 and Fig.13 As 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, thereby improving the clarity of the near-eye display system.

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

[0096] like Fig.14 As shown, the near-eye display system may 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.

[0097] like Fig.15As shown, the near-eye display system may further include a free-form surface reflector 4, the display panel 2 and the liquid crystal microlens array 1 are tiltedly arranged between the free-form surface reflector 4 and the eyeball, the free-form surface reflector 4 is located on the outgoing light of the liquid crystal microlens array 1, and the outgoing light is reflected to the eyeball by the microlens array. Similarly, the depth of field of the near-eye display system can be adjusted by adjusting the focal length of the liquid crystal microlens array 1 in real time. The arrangement of the free-form surface reflector 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 appreciate other embodiments of the present invention after considering the specification and practicing the invention invented 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 common knowledge or customary techniques in the art that are not invented by the present invention. The specification and examples are intended to be exemplary only, and the true scope and spirit of the present invention are indicated by the appended claims.

Claims

1. A liquid crystal microlens array, characterized in that: include: A liquid crystal box, comprising a liquid crystal layer, a first substrate and a second substrate, wherein the liquid crystal layer has a first surface and a second surface arranged opposite to each other, the first substrate is arranged on the first surface of the liquid crystal layer, and the second substrate is arranged on the second surface of the liquid crystal layer; m1 first electrode strips are arranged on a side of the first substrate close to the liquid crystal layer, the first electrode strips extend along a first direction, 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 are arranged on a side of the second substrate close to the liquid crystal layer, the second electrode strips extend along a second direction, 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 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 intersect with the orthographic projections of the first electrode strips on the first substrate 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, and a curved microlens is formed at each n1×n2 intersection, 2≤n1≤m1, 2≤n2≤m2.

2. The liquid crystal microlens array according to claim 1, characterized in that: The m1 number of the first electrode strips includes at least two groups of first electrode strips, and the m2 number of the second electrode strips includes at least two groups of second electrode strips. By controlling the voltage value of each 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 two adjacent first electrode strips is the same as the distance between two 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 both are the first distances. 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 size of the first distance.

4. The liquid crystal microlens array according to claim 1, characterized in that: The distance between two adjacent first electrode strips is different from the distance between two adjacent second electrode strips. When n1=n2, when the distance between the first electrode strips is greater than the distance between two 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 smaller than the component in the second direction. When the distance between the first electrode strips is smaller than the distance between two 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 formed at n1×n2 intersections in the first direction is larger than the component in the second direction.

5. The liquid crystal microlens array according to claim 1, characterized in that: m1 first electrode strips are supplied with 1-n1 voltage signals, and m2 second electrode strips are supplied 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 smaller 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 larger than that in the second direction.

6. The liquid crystal microlens array according to claim 1, characterized in that: The number of the first electrode strips in each group is greater than or equal to 10, the number of the second electrode strips in each group is greater than or equal to 10, and 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, characterized in that: An angle between the second direction and the first direction is greater than 45 degrees and less than 135 degrees.

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

9. The driving method of the liquid crystal microlens array according to claim 8, characterized in that: The first electrode strip and the voltage signal loaded thereon 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 potential of the first electrode strip at the position; The second electrode strip and the voltage signal loaded thereon satisfy 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 at any point (x, y) in the liquid crystal box 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) in the liquid crystal cell is: △V = x 2 +y 2 .

11. The driving method of the liquid crystal microlens array according to claim 9, characterized in that: The method further comprises: The initial voltage signal of m1 first electrode strips is translated from x1 to x2 along the first direction, x2>x1, and the first electrode strip and the voltage signal loaded thereon satisfy the following relationship: Vx=f(x)+a, a=x2-x1; and / or the initial voltage signal of m2 second electrode strips is translated from y1 to y2 along the second direction, y2>y1, and the second electrode strip and the voltage signal loaded thereon satisfy the following relationship: Vy=-g(y)+b, b=y2-y1; Each of the curved microlenses is translated along the first direction a and / or along the second direction b.

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

14. A near-eye display system, characterized in that: include: Display panel; The liquid crystal microlens array according to any one of claims 1 to 7, arranged on the display side of the display panel, the liquid crystal microlens array and the display panel are parallel to each other; The aperture of the curved microlens satisfies the formula: Sh×n t / L≤D≤S×n t ; The focal length of the curved microlens satisfies the formula: 1 / f=1 / (h×n t )-1 / H; The curvature radius of the curved microlens satisfies the formula: r = f(n e -n o ); The arch 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, n is the distance between the eyeball and the curved microlens, and n is the distance between the eyeball and the curved microlens. 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 liquid crystal for ordinary light, n e is the refractive index of 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 according to claim 14, characterized in that: 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 according to claim 14, characterized in that: The near-eye display system also includes a free-form surface reflector, the display panel and the liquid crystal microlens array are tiltedly arranged between the free-form surface reflector and the eyeball, the free-form surface reflector is located on the outgoing light of the liquid crystal microlens array, and the outgoing light is reflected by the microlens array to the eyeball.

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