Micro-structure multi-view cooperative light control light field display device

Abstract

The invention provides a microstructure multi-view cooperative light control light field display device, and relates to the field of light field display, and light field display system hardware is divided into an upper layer, a middle layer and a lower layer: the lower layer is a light guide plate, the middle layer is a microstructure array, and the upper layer is a screen. According to the invention, the display elements are utilized more efficiently, the lighting effect is improved, the size of the display equipment is reduced, the three-dimensional display effect with gradually-changed viewpoint density can be realized, and the light field display technology continuously goes forward to a new height.

Description

Technical Field

[0001] The present invention belongs to the field of light field display, and in particular relates to a light field display device with microstructure multi-viewing angle coordinated light control. Background Art

[0002] Three-dimensional light field display technology has become the most mature and widely used 3D display technology. It not only has broad application prospects in entertainment fields such as games and movies, but also has great potential in education, medical care, industrial design and other fields. Light field display technology continues to develop in the direction of low cost and high performance, and in-depth research is conducted on how to improve light energy utilization, display viewing angle and device material reliability. At the same time, it is necessary to meet the market demand for high resolution and large-scale display elevation angles to ensure that viewers can see clear true three-dimensional images at different angles.

[0003] However, traditional light field display systems have pain points such as display information crosstalk, large overall system thickness, and low device light energy utilization, which seriously affect the audience's experience. Summary of the invention

[0004] In view of the above-mentioned deficiencies in the prior art, the present invention provides a light field display device with microstructure multi-viewing angle collaborative light control, which solves important problems of traditional light field display in display effect, equipment volume, device light energy utilization rate, etc.

[0005] In order to achieve the above objectives, the technical solution adopted by the present invention is: a light field display device with microstructure multi-viewing angle coordinated light control, comprising an edge-entry light source, a light guide plate, a micro-cut continuous microstructure and a screen;

[0006] The side-entry light source is incident on the light guide plate, undergoes total reflection in the light guide plate, and is transmitted in the light guide plate. When the light beam propagates to the bonding position between the light guide plate and the continuous microstructure, the light beam propagating in the light guide plate is destroyed by the total reflection condition, and the light beam is incident from the light guide plate to the continuous microstructure, wherein a part of the light beam is directly transmitted at the continuous microstructure, and another part of the light beam is totally reflected at the protruding surface of the continuous microstructure.

[0007] A multi-view collaborative light control display algorithm is used to encode screen pixels so that the light information displayed on the screen contains spatial light field information. The light beam emitted by the continuous microstructure light source is loaded with the light information displayed on the screen, and is transmitted from the screen to multiple positions in space, and converges into a set of pixels to form a light field display.

[0008] Furthermore, the continuous microstructure is composed of a periodic arrangement of single micro-cut microstructures, each microstructure includes an upper end plane and a protruding surface, the lower end of the protruding surface is a bonding area, which is bonded to the light guide plate; the upper end plane is loaded on a PET substrate, and the PET substrate is bonded to the screen, wherein the continuous microstructure is first prepared in a conventional manner, and then the continuous microstructure is micro-cut by laser cutting or a diamond tool.

[0009] Furthermore, the light guide plate and the continuous microstructure are adhered with a transparent glue having a transmittance greater than 70%, wherein the refractive index of the transparent glue is consistent with that of the light guide plate, and the protruding surface of the microstructure and the immersed part of the transparent glue are not less than 1 / 10 of the arch height and not more than 1 / 2 of the arch height.

[0010] Furthermore, the microstructure selects an elliptical cylindrical lens, wherein the expression of the curvature radius of the elliptical cylindrical lens is as follows:

[0011]

[0012] Among them, a represents the semi-major axis of the ellipse, b represents the semi-minor axis of the ellipse, and c represents the semi-focal length of the ellipse, and the semi-focal length is approximately equal to the semi-major axis.

[0013] Furthermore, the light beam is incident into the microstructure from both sides of the light guide plate, the incident angle is greater than the critical angle of total reflection, and first converges to the lower convergence points between the upper surface of the light-transmitting glue and the edges of both sides of the microstructure. The two lower convergence points are symmetrical along the short axis of the ellipse. A part of the light beam passing through the two lower convergence points is directly transmitted out on the upper surface of the microstructure, and the light information loaded therein is the light field display information with a large viewing angle. The other part of the light beam is totally reflected on the protruding surface of the microstructure, and the direction of the light beam is deflected through total reflection. The deflected light beam converges at the two upper convergence points of the elliptical cylindrical lens. The distance between the two upper convergence points is the focal length of the ellipse, and the light information loaded therein is the light field information with a small viewing angle.

[0014] Furthermore, the two lower convergence points and the two upper convergence points are regarded as point light sources and compensate each other, and the four convergence points form an encapsulated isosceles trapezoid. Furthermore, the light angle of the edge-entry light source is greater than or equal to 120 degrees, the thickness of the light guide plate is not less than 0.05 mm and not more than 5 cm, the thickness of the screen is not more than 0.5 mm, and the plane connection between two adjacent microstructures is coated with a coating with light absorption ability, and the width of the coating is not more than 50 um.

[0015] Furthermore, the multi-viewing angle collaborative light control display algorithm is used to encode screen pixels, which is specifically:

[0016] Based on the array light source generated at the screen corresponding to the elliptical cylindrical lens as an array line light source, horizontal parallax encoding is performed on the pixels, wherein the microstructure forms a directly transmitted large-angle deflected light beam and a small-angle deflected light beam after total reflection at the edges on both sides; horizontal parallax encoding is performed on the pixels corresponding to the large-angle deflected light beam and the small-angle deflected light beam on the left and right sides of the microstructure respectively;

[0017] In light field coding, a ray tracing algorithm is used to trace back the spatial voxels to be constructed to the display plane for periodic information encoding.

[0018] Furthermore, the preparation process comprises the following steps:

[0019] Institutional metal molds;

[0020] The polymer is heated to a softening point;

[0021] After cooling, the mold is demoulded to obtain a periodic continuous microstructure;

[0022] Use a conventional laser cutting machine or diamond tool to micro-cut the periodic continuous microstructure, and control the size deviation of the microstructure after cutting to be between ±5μm and ±20μm. Check the protrusion surface after cutting, wherein the microstructure adopts a continuous large-pitch elliptical cylindrical lens;

[0023] The light guide plate and the periodic continuous microstructure are adhered to each other with a light-transmitting adhesive, the lower end of the protrusion surface of each microstructure is attached to the light guide plate, the upper end plane is processed on the PET substrate, and the PET substrate is attached to the screen, wherein a part of the light beam in the microstructure passes through the lower convergence point and is directly transmitted from the upper end plane, and the other part of the light beam passes through the lower convergence point and is totally reflected at the edges of the protrusion surfaces on both sides of the microstructure array, and is emitted from the upper end plane of the microstructure array, and its propagation direction is regulated by the surface shape of the protrusion surface of the microstructure array, thereby forming an array light source that can emit light beams at multiple angles;

[0024] A multi-view collaborative light control display algorithm is used to encode screen pixels so that the light information displayed on the screen contains spatial light field information. The light beam emitted by the continuous microstructure light source is loaded with the light information displayed on the screen, and is transmitted from the screen to multiple positions in space, and converges into a set of pixels to form a light field display.

[0025] The beneficial effects of the present invention are:

[0026] The present invention provides a light field display device with microstructure multi-viewing angle coordinated light control. The system includes: an edge-entry light source, a light guide plate, a continuous microstructure array after micro-cutting, and a screen. The present invention first prepares the continuous microstructure in a conventional manner, and then micro-cuts the continuous microstructure by a laser cutting machine or a diamond tool. The lower end of the protruding surface of each microstructure of the array is bonded to the light guide plate, and the upper end plane is processed on a PET substrate, and the PET substrate is bonded to the screen. A part of the light beam in the microstructure is directly transmitted, and the other part of the light beam is totally reflected at the edge of the protruding surface of the microstructure array, and its direction is changed, and it is emitted from the plane of the microstructure array. Its propagation direction is regulated by the surface shape of the protruding surface of the microstructure array, thereby forming an array light source that can emit light beams at multiple angles. The screen pixels are encoded using a multi-viewing angle coordinated light control display algorithm, so that the light information displayed on the screen contains spatial light field information. The light beam emitted by the array light source is loaded with the light information displayed on the screen, and is transmitted from the screen, emitted to multiple positions in space, and converged into a body pixel set to form a light field display effect that can be viewed by the human eye. The present invention utilizes display elements more efficiently, improves light efficiency, reduces the volume of display equipment, and can achieve a three-dimensional display effect with a gradual change in viewpoint density, thereby continuously advancing light field display technology to new heights. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 It is a plan view of the light field display system of the present invention.

[0028] Figure 2 It is a light path diagram in the microstructure of the present invention.

[0029] Figure 3 Process map for continuous microstructure production.

[0030] Figure 4 Schematic diagram of the four convergence points formed in the microstructure.

[0031] Figure 5 Viewpoint distribution map encoded for horizontal disparity.

[0032] Figure 6 Encodes the horizontal disparity pixel map at the screen. DETAILED DESCRIPTION

[0033] The specific implementation modes of the present invention are described below so that those skilled in the art can understand the present invention. However, it should be clear that the present invention is not limited to the scope of the specific implementation modes. For those of ordinary skill in the art, as long as various changes are within the spirit and scope of the present invention as defined and determined by the attached claims, these changes are obvious, and all inventions and creations utilizing the concept of the present invention are protected.

[0034] Example 1

[0035] like Figure 1 , Figure 2 and Figure 3 As shown, the present invention provides a light field display device with microstructure multi-viewing angle coordinated light control, including an edge-entry light source, a light guide plate, a continuous microstructure after micro-cutting, and a screen;

[0036] The side-entry light source is incident on the light guide plate, and is totally reflected in the light guide plate and transmitted in the light guide plate. When the light beam propagates to the joint position between the light guide plate and the continuous microstructure, the light beam propagating in the light guide plate is destroyed by the total reflection condition. The light beam is incident from the light guide plate to the continuous microstructure, where part of the light beam is directly transmitted at the continuous microstructure, and the other part of the light beam is totally reflected at the protruding surface of the continuous microstructure, that is:

[0037] The side-entry light source is incident on the light guide plate, undergoes total reflection in the light guide plate, and is transmitted in the light guide plate. When the light beam propagates to the fitting position of the light guide plate and the continuous microstructure, the light beam propagating in the light guide plate is destroyed due to the total reflection condition, and the light beam is incident on the continuous microstructure from the light guide plate. Part of the light beam passes through the lower convergence point and is directly transmitted at the upper plane of the continuous microstructure, while the other part of the light beam passes through the lower convergence point and undergoes total reflection at the protrusions on both sides of the continuous microstructure, and its direction changes, and is emitted from the upper plane of the microstructure array. Its propagation direction is regulated by the surface shape of the protrusions of the microstructure, and the two parts of the light beam together form an array light source that can emit light beams at multiple angles. A multi-view collaborative light control display algorithm is used to encode screen pixels, so that the light information displayed on the screen contains spatial light field information. The light beam emitted by the continuous microstructure light source is loaded with the light information displayed on the screen, and is transmitted from the screen, emitted to multiple positions in space, and converged into a body pixel set to form a light field display.

[0038] In this embodiment, the continuous microstructure is composed of a single microstructure that has been micro-cut and arranged periodically, and each microstructure includes an upper end plane and a protruding surface, and the lower end of the protruding surface is a bonding area that is bonded to the light guide plate; the upper end plane is loaded on a PET substrate, and the PET substrate is bonded to the screen, wherein the continuous microstructure is first prepared in a conventional manner, and then the continuous microstructure is micro-cut by laser cutting or a diamond tool. The light angle of the side-entry light source is greater than or equal to 120 degrees, the thickness of the light guide plate is not less than 0.05mm and not more than 5cm, the thickness of the screen is not more than 0.5mm, and the plane connection of two adjacent microstructures is coated with a coating with light absorption ability, and the width of the coating is not more than 50um. The light guide plate and the continuous microstructure are bonded with a light-transmitting adhesive with a light transmittance greater than 70%, wherein the refractive index of the light-transmitting adhesive is consistent with that of the light guide plate, and the protruding surface of the microstructure and the immersed part of the light-transmitting adhesive are not less than 1 / 10 of the arch height and not more than 1 / 2 of the arch height.

[0039] In this embodiment, Figure 1 and Figure 2 As shown, the hardware of the light field display system is divided into three layers: the lower layer is the light guide plate, the middle layer is the microstructure array, and the upper layer is the screen. The side-entry light source is incident from the edge of the light guide plate to the inside of the light guide plate, and is totally reflected in the "non-light guide plate-microstructure bonding area" inside it. The side-entry light source adopts the preferred LED lamp beads or light strips, and the light output angle of the lamp beads or light strips is greater than or equal to 120°. The luminous brightness of the lamp beads or light strips is controlled by a voltage-stabilized power supply, and its luminous brightness is generally not less than 50 (lm) and not more than 500 (lm) to ensure that the screen is not too dark or too bright. In order to achieve high-quality display effects, the protruding surface of the microstructure array faces the light guide plate, and is pasted to the "light guide plate-microstructure bonding area" with a light-transmitting adhesive. The upper plane is bonded to the screen through a PET substrate, thereby achieving a close fit between the three.

[0040] In this embodiment, the microstructure array fits tightly with the light guide plate and the screen: the tight fitting design of the three in the present invention is one of its core highlights, making the optical system thinner and lighter. The light guide plate is made of a highly transparent material so that the light beam can be effectively transmitted. The periodic microstructure array adopts a continuous micro-light-transmitting device, and a high-transparency glue is used to bond the protruding surface of the microstructure array to the light guide plate. In the selection of the optical structure, the microstructure preferably has an elliptical cylindrical lens with an elliptical cross-section. In order to improve the effect of three-dimensional display, an elliptical cylindrical lens grating with a small curvature radius and an eccentricity close to 1 is preferably designed. The eccentricity is close to 1, indicating that the semi-focal length and semi-major axis of the ellipse are approximately equal, and the position of the light beam convergence point is changed by adjusting the eccentricity of the ellipse, so that the diffuse spot generated at the viewpoint is smaller than the size of the sub-pixel, which lays a good foundation for subsequent light field display encoding.

[0041] In this embodiment, Figure 2 As shown, the light source adopts an edge-entry backlight, and the light beam emitted by it is incident from the side of the light guide plate to the inside of the light guide plate, and is totally reflected inside. The principle of the light guide plate is mainly based on the total reflection optical effect. In order to prevent the light beam from escaping from the "non-light guide plate-microstructure bonding area" and causing insufficient light efficiency, a high-refractive index substrate with a smaller Brewster angle is preferred. The light beam undergoes multiple total reflections inside the light guide plate. When it does not pass through the "light guide plate-microstructure bonding area", the light beam will not be emitted from the upper surface; when passing through the "light guide plate-microstructure bonding area", the total reflection condition is destroyed, and the light beam is incident from the light guide plate into the microstructure array.

[0042] In this embodiment, Figure 3As shown, from the perspective of preparation process, the microstructure is preferably a continuous large-pitch cylindrical lens. However, adjacent microstructures are prone to bridging during processing, and high-quality three-dimensional display effects cannot be achieved. Therefore, a conventional laser cutting machine or diamond tool is used to micro-cut the continuous cylindrical lens microstructure, and the structural size deviation after cutting should be controlled between ±5μm and ±20μm, and an optical microscope or scanning electron microscope is used to check the protruding structure after cutting to ensure that the size, shape and position of each microstructure meet the design requirements.

[0043] In this embodiment, the preferred thickness of the light guide plate should not be less than 0.05 mm and should not exceed 5 cm. Within this range, the light beam is evenly propagated in the light guide plate, which improves the utilization rate of light energy. If the thickness of the light guide plate is too small, most of the light beam will be emitted from the "light guide plate-microstructure bonding area" close to the side-entry light source, and only a small amount of light beam will be emitted from the "light guide plate-microstructure bonding area" far away from the light source, which will lead to uneven brightness distribution of the screen and affect the effect of three-dimensional display; if the thickness of the light guide plate is too large, it will cause the light beam to propagate a longer distance in the light guide plate, and the light beam in the light guide plate will be lost, which will reduce the utilization rate of light energy and affect the brightness of the three-dimensional display.

[0044] In this embodiment, the light guide plate and the microstructure array are adhered by a light-transmitting adhesive with a transmittance greater than 70%. The material is preferably UV curing adhesive or OCA adhesive, and the refractive index of the light-transmitting adhesive must be consistent with that of the light guide plate. The protruding surface of the microstructure and the immersed part of the light-transmitting adhesive should preferably not be less than 1 / 10 of the arch height and not more than 1 / 2 of the arch height. If the protruding surface of the microstructure and the immersed part of the light-transmitting adhesive exceed 1 / 2 of the arch height, the light beam is directly transmitted from the microstructure and cannot be fully reflected on the protruding surface, resulting in uneven energy distribution generated by the angle of the light beam; if the contact part between the protruding surface of the microstructure and the light-transmitting adhesive is less than 1 / 10 of the arch height, only a small amount of light beam is incident from the light guide plate into the microstructure, making the screen brightness darker and unable to achieve high-quality three-dimensional display.

[0045] In this embodiment, the microstructure is an elliptical cylindrical lens.

[0046] In this embodiment, the luminous area generated by a single microstructure is affected by the microstructure surface shape. In order to solve the problem of more stray light generated by the edge of the microstructure, in the selection of the optical structure, the microstructure is preferably an elliptical cylindrical lens with an elliptical cross section. In order to improve the effect of three-dimensional display, it is preferred to design an elliptical cylindrical lens with a small curvature radius and an eccentricity close to 1. A small curvature radius and an eccentricity close to 1 can increase the focusing ability of the elliptical cylindrical lens, thereby converging more light into a smaller area. The curvature radius of the elliptical cylindrical lens follows the formula:

[0047]

[0048] Among them, a represents the semi-major axis of the ellipse, b represents the semi-minor axis of the ellipse, and c represents the semi-focal length of the ellipse, which is approximately equal to the semi-major axis. Shortening the length of the minor axis can reduce the radius of curvature of the elliptical cylindrical lens. At the same time, by adjusting the eccentricity of the ellipse, the position of the light beam convergence point can be changed, thereby effectively reducing the crosstalk between light beams, laying a good foundation for the subsequent multi-view collaborative light control light field display algorithm.

[0049] In the present embodiment, the light beam is incident into the microstructure from both sides of the light guide plate, the incident angle is greater than the critical angle of total reflection, and first converges to the lower convergence points between the upper surface of the light-transmitting glue and the edges of both sides of the microstructure. The two lower convergence points are symmetrical along the short axis of the ellipse. A part of the light beam passing through the two lower convergence points is directly transmitted out on the upper surface of the microstructure, and the light information loaded therein is the light field display information with a large viewing angle. The other part of the light beam is totally reflected on the protruding surface of the microstructure, and the direction of the light beam is deflected through total reflection. The deflected light beam converges at the two upper convergence points of the elliptical cylindrical lens. The distance between the two upper convergence points is the focal length of the ellipse, and the light information loaded therein is the light field information with a small viewing angle.

[0050] In this embodiment, Figure 4 As shown, the light beam is incident on the microstructure from both sides of the light guide plate. The incident angle must be greater than the critical angle of total reflection, and first converges to the contact point between the upper surface of the light-transmitting glue and the edges of the two sides of the microstructure (called the lower convergence point). The two lower convergence points are symmetrical along the short axis of the ellipse. The origin of the ellipse is set to (0,0). The direction along the long axis of the ellipse from left to right is recorded as the x-axis, and the direction along the short axis of the ellipse from bottom to top is recorded as the y-axis to establish a plane rectangular coordinate system. The position of the lower convergence point 1 can be expressed as (-x, -y), and the position of the lower convergence point 2 can be expressed as (x, -y). The distance calculated by the lower convergence point 1 follows the formula (in this embodiment, refer to Figure 4 The method of establishing a plane rectangular coordinate system is to represent the two convergence points below in the coordinate system, and calculate the distance D through the convergence point 1 below. Of course, due to the axisymmetric characteristics of the ellipse, it is also possible to calculate through the coordinates of the convergence point 2 below, just substitute (x, -y)):

[0051]

[0052] Wherein, d represents the length of the protruding surface of the microstructure and the part immersed in the light-transmitting glue, and b represents the semi-minor axis of the ellipse. The positions of the two lower convergence points can be changed by changing the depth of the protruding surface of the microstructure and the light-transmitting glue immersion. A part of the light beam passing through the lower convergence point is directly transmitted on the upper surface of the microstructure, and the light information loaded is the light field display information with a large viewing angle; the other part of the light beam is totally reflected on the protruding surface of the microstructure after passing through the lower convergence point, and the direction of the light beam is deflected after total reflection. The deflected light beam converges at the two foci of the elliptical cylindrical lens (called the upper convergence points). The distance between the two upper convergence points is the focal length of the ellipse, 2c, and the light information loaded is the light field display information with a small viewing angle. Both parts of the light beam are emitted from the microstructure plane, so that a light source that can simultaneously emit multi-angle light beams is formed at the microstructure plane.

[0053] In this embodiment, the two lower convergence points and the two upper convergence points are all regarded as point light sources and compensate each other, and the four convergence points form an encapsulated isosceles trapezoid.

[0054] In this embodiment, Figure 4 As shown in the figure, the four convergence points formed in the microstructure can be regarded as point light sources and compensate each other. The four convergence points can form a closed isosceles trapezoid, which can effectively improve the light efficiency. The distance between the lower convergence point and the upper convergence point on the same side follows the following formula, taking convergence point 1 as an example:

[0055]

[0056] Wherein, d represents the length between the protruding surface of the microstructure and the immersed part of the light-transmitting glue, b represents the semi-minor axis of the ellipse, and c represents the semi-focal length of the ellipse.

[0057] In this embodiment, the calculation is performed by taking the convergence point 1 as an example. Since the ellipse is symmetrical, the calculation results of the convergence point 1 and the convergence point 2 are exactly the same, which will not be repeated here.

[0058] In this embodiment, in order to effectively reduce the large-angle stray light generated by the microstructure, it is preferred to control the thickness of the LCD display screen within 0.5 mm. This thickness range significantly reduces the crosstalk phenomenon between light beams. If the thickness of the display screen exceeds 0.5 mm, most of the large-angle stray light may leak from both sides of the screen, thereby seriously affecting the uniformity of the light beam. In addition, in order to further suppress large-angle stray light, a coating with strong light absorption ability is required to be coated at the planar connection between two adjacent microstructures. The coating width should preferably not exceed 50 um. The coating can effectively absorb stray light, thereby improving the quality of three-dimensional display.

[0059] In this embodiment, a multi-viewing angle collaborative light control display algorithm is used to encode screen pixels, which is specifically:

[0060] Based on the array light source generated at the screen corresponding to the elliptical cylindrical lens as an array line light source, horizontal parallax encoding is performed on the pixels, wherein the microstructure forms a directly transmitted large-angle deflected light beam and a small-angle deflected light beam after total reflection at the edges of both sides; horizontal parallax encoding is performed on the pixels corresponding to the large-angle deflected light beam and the small-angle deflected light beam on the left and right sides of the microstructure respectively (in this embodiment, the encoding method of the large-angle deflected light beam and the small-angle deflected light beam of the microstructure is the same, and the innovation of the present invention is based on the surface shape of the lens and the encoding method to produce a three-dimensional display effect with dense viewpoints in the middle viewing area and sparse viewpoints in the viewing areas on both sides);

[0061] In light field coding, a ray tracing algorithm is used to trace back the spatial voxels to be constructed to the display plane for periodic information encoding.

[0062] In this embodiment, the display plane has a large number of information display units, and its information layout is determined according to the spatial volume pixel distribution of the three-dimensional display. Horizontal parallax encoding is performed according to the selected continuous large-pitch elliptical cylindrical lens grating. The light field encoding adopts a ray back-tracing algorithm, and the spatial voxels to be constructed are traced back to the display plane for periodic information encoding. The array light source generated at the screen corresponding to the elliptical cylindrical lens is an array line light source, and the pixels need to be horizontally parallax encoded. The microstructure can form a directly transmitted large-angle deflected light beam and a small-angle deflected light beam that is totally reflected at the edges on both sides. The viewpoints corresponding to the large-angle deflected light beam are relatively sparse, and the viewpoints corresponding to the small-angle deflected light beam are relatively dense. The pixels corresponding to the large-angle deflected light beams on the left and right sides of the microstructure are horizontally and continuously encoded (1,2,…,m), (Nm,…,N-1,N), and the pixels corresponding to the small-angle deflected light beams on the left and right sides of the microstructure are encoded separately. The pixels corresponding to the small-angle deflected light beams on the right are encoded from left to right. Continuous encoding, the pixels corresponding to the small-angle deflected beam on the left are from left to right Continuous encoding is performed. Continuous viewpoints can be formed at the best viewing position, and continuous ultra-dense viewpoints can be formed in the middle viewing area (such as Figure 5 and Figure 6 As shown in the figure Viewpoint, Figure 6 The corresponding disparity map number is assigned to the sub-pixels under each microstructure), and the viewpoints in the viewpoint areas at both ends are sparse. In order to effectively avoid crosstalk between pixels, a coating with strong light beam absorption ability is applied to the contact part of the two microstructures to isolate part of the large-angle deflected light beam, effectively realizing a three-dimensional display system with a gradual change in viewpoint density, where m represents a positive integer, indicating the rightmost viewpoint number corresponding to the large-angle deflected light beam on the left; N represents the total number of viewpoints, which can also be understood as the viewpoint number of the rightmost pixel covered by a microstructure.

[0063] In this embodiment, encoding is one of the innovative points of the present invention. The present invention divides the light beam emitted from the microstructure into four parts through the surface design of the microstructure, large-angle light beams on the left and right sides and small-angle light beams on both sides. The large-angle deflected light beam is first encoded from the left according to the deflection angle of the light beam. 1 is the leftmost viewpoint number corresponding to the large-angle deflected light beam on the left, and m is a constant and a positive integer, which represents the rightmost viewpoint number corresponding to the large-angle deflected light beam on the left. The encoding method of other deflected light beams is similar. After that, the small-angle deflected light beam on the right is pixel-encoded. Since the effect presented by the light beam is axisymmetric, N / 2 is the number of middle viewpoints. Since the middle viewpoints are dense and the viewpoints at both ends are sparse, it is necessary to ensure that m is small and Nm is large when dividing (1...m, Nm...N contains fewer viewpoints).

[0064] In this embodiment, the preparation process of the light field display device includes the following steps:

[0065] Institutional metal molds;

[0066] The polymer is heated to a softening point;

[0067] After cooling, the mold is demoulded to obtain a periodic continuous microstructure;

[0068] Use a conventional laser cutting machine or diamond tool to micro-cut the periodic continuous microstructure, and control the size deviation of the microstructure after cutting to be between ±5μm and ±20μm. Check the protrusion surface after cutting, wherein the microstructure adopts a continuous large-pitch elliptical cylindrical lens;

[0069] The light guide plate and the periodic continuous microstructure are adhered to each other with a light-transmitting adhesive, the lower end of the protrusion surface of each microstructure is attached to the light guide plate, the upper end plane is processed on the PET substrate, and the PET substrate is attached to the screen, wherein a part of the light beam in the microstructure passes through the lower convergence point and is directly transmitted from the upper end plane, and the other part of the light beam passes through the lower convergence point and is totally reflected at the edges of the protrusion surfaces on both sides of the microstructure array, and is emitted from the upper end plane of the microstructure array, and its propagation direction is regulated by the surface shape of the protrusion surface of the microstructure array, thereby forming an array light source that can emit light beams at multiple angles;

[0070] A multi-view collaborative light control display algorithm is used to encode screen pixels so that the light information displayed on the screen contains spatial light field information. The light beam emitted by the continuous microstructure light source is loaded with the light information displayed on the screen, and is transmitted from the screen to multiple positions in space, and converges into a set of pixels to form a light field display.

[0071] In this embodiment, from the perspective of the preparation process, the microstructure is preferably a continuous large-pitch column lens grating. The preparation process is preferably a hot pressing molding method, and its process is: 1. Make a high-precision metal mold. 2. Heat the polymer to the softening point. 3. Demold after cooling to obtain a continuous microstructure. However, adjacent microstructures are prone to bridging during the processing process. The bridging part of the microstructure transmits a large amount of light beams, and a large amount of stray light can be seen at the screen, resulting in uneven brightness distribution of the screen, and it is impossible to achieve a high-quality three-dimensional display effect. Therefore, a conventional laser cutting machine or diamond tool is used to micro-cut the continuous column lens microstructure, and the structural size deviation after cutting should be controlled between ±5μm and ±20μm, and an optical microscope or scanning electron microscope is used to check the protruding structure after cutting to ensure that the size, shape and position of each microstructure meet the design requirements.

[0072] In summary, the present invention first prepares a periodic continuous microstructure in a conventional manner, and then microcuts the periodic continuous microstructure by a laser cutting machine or a diamond tool. The lower end of the protruding surface of each microstructure of the array is bonded to the light guide plate, and the upper plane is processed on the PET substrate, and the PET substrate is bonded to the screen. Part of the light beam in the microstructure passes through the lower convergence point and is directly transmitted from the upper plane, and the other part of the light beam passes through the lower convergence point and is totally reflected at the edges of the protruding surfaces on both sides of the microstructure array, and is emitted from the upper plane of the microstructure array. Its propagation direction is regulated by the surface shape of the protruding surface of the microstructure array, thereby forming an array light source that can emit light beams at multiple angles (the innovation of the present invention is to form four mutually compensating light points in the microstructure, the advantage is that the light effect is better and the light beam has better directionality); a multi-view collaborative light control display algorithm is used to encode the screen pixels, so that the light information displayed on the screen contains spatial light field information. The light beam emitted by the array light source is loaded with the light information displayed on the screen, and is transmitted from the screen, emitted to multiple positions in space, and converged into a body pixel set to form a light field display effect that can be viewed by the human eye. The system includes: an edge-entry light source, a light guide plate, a continuous microstructure after micro-cutting, and a screen. The present invention utilizes display elements more efficiently, improves light efficiency, reduces the volume of display devices, and can achieve a three-dimensional display effect with a gradual change in viewpoint density, making light field display technology continue to move towards new heights.

Claims

1. A light field display device with microstructure multi-viewing angle coordinated light control, characterized in that: It includes an edge-entry light source, a light guide plate, a micro-cut continuous microstructure, and a screen; The side-entry light source is incident on the light guide plate, undergoes total reflection in the light guide plate, and is transmitted in the light guide plate. When the light beam propagates to the bonding position between the light guide plate and the continuous microstructure, the light beam propagating in the light guide plate is destroyed by the total reflection condition, and the light beam is incident from the light guide plate to the continuous microstructure, wherein a part of the light beam is directly transmitted at the continuous microstructure, and another part of the light beam is totally reflected at the protruding surface of the continuous microstructure. A multi-view collaborative light control display algorithm is used to encode screen pixels so that the light information displayed on the screen contains spatial light field information. The light beam emitted by the continuous microstructure light source is loaded with the light information displayed on the screen, and is transmitted from the screen to multiple positions in space, and converges into a set of pixels to form a light field display.

2. The light field display device with microstructure multi-viewing angle coordinated light control according to claim 1, characterized in that: The continuous microstructure is composed of a periodic arrangement of single microstructures that have been micro-cut, and each microstructure includes an upper end plane and a protruding surface, and the lower end of the protruding surface is a bonding area that is bonded to the light guide plate; the upper end plane is loaded on a PET substrate, and the PET substrate is bonded to the screen, wherein the continuous microstructure is first prepared in a conventional manner, and then the continuous microstructure is micro-cut by laser cutting or a diamond tool.

3. The light field display device with microstructure multi-viewing angle coordinated light control according to claim 2, characterized in that: The light guide plate and the continuous microstructure are adhered with a transparent glue having a transmittance greater than 70%, wherein the refractive index of the transparent glue is consistent with that of the light guide plate, and the protruding surface of the microstructure and the immersed part of the transparent glue are not less than 1 / 10 of the arch height and not more than 1 / 2 of the arch height.

4. The light field display device with microstructure multi-viewing angle coordinated light control according to claim 2, characterized in that: The microstructure is an elliptical cylindrical lens, wherein the expression of the curvature radius of the elliptical cylindrical lens is as follows: Among them, a represents the semi-major axis of the ellipse, b represents the semi-minor axis of the ellipse, and c represents the semi-focal length of the ellipse, and the semi-focal length is approximately equal to the semi-major axis.

5. The light field display device with microstructure multi-viewing angle coordinated light control according to claim 4, characterized in that: The light beam is incident into the microstructure from both sides of the light guide plate, with an incident angle greater than the critical angle of total reflection, and first converges to the lower convergence points between the upper surface of the light-transmitting glue and the edges of both sides of the microstructure. The two lower convergence points are symmetrical along the short axis of the ellipse. A part of the light beam passing through the two lower convergence points is directly transmitted out on the upper surface of the microstructure, and the light information loaded therein is the light field display information with a large viewing angle. The other part of the light beam is totally reflected on the protruding surface of the microstructure, and the direction of the light beam is deflected through total reflection. The deflected light beam converges at the two upper convergence points of the elliptical cylindrical lens. The distance between the two upper convergence points is the focal length of the ellipse, and the light information loaded therein is the light field display information with a small viewing angle.

6. The light field display device with microstructure multi-viewing angle coordinated light control according to claim 5, characterized in that: The two lower convergence points and the two upper convergence points are all regarded as point light sources and compensate each other. The four convergence points form an encapsulated isosceles trapezoid.

7. The light field display device with microstructure multi-viewing angle coordinated light control according to claim 1, characterized in that: The light angle of the edge-entry light source is greater than or equal to 120 degrees, the thickness of the light guide plate is not less than 0.05 mm and not more than 5 cm, the thickness of the screen does not exceed 0.5 mm, and the planar connection between two adjacent microstructures is coated with a coating with light absorption ability, and the width of the coating does not exceed 50 um.

8. The light field display device with microstructure multi-viewing angle coordinated light control according to claim 1, characterized in that: The multi-view collaborative light control display algorithm is used to encode screen pixels, which is specifically: Based on the array light source generated at the screen corresponding to the elliptical cylindrical lens as an array line light source, horizontal parallax encoding is performed on the pixels, wherein the microstructure forms a directly transmitted large-angle deflected light beam and a small-angle deflected light beam after total reflection at the edges on both sides; horizontal parallax encoding is performed on the pixels corresponding to the large-angle deflected light beam and the small-angle deflected light beam on the left and right sides of the microstructure respectively; In light field coding, a ray tracing algorithm is used to trace back the spatial voxels to be constructed to the display plane for periodic information encoding.

9. A light field display device with microstructure multi-viewing angle collaborative light control as claimed in any one of claims 1 to 8, characterized in that: The preparation process of the light field display device comprises the following steps: Institutional metal molds; heating the polymer to a softening point; After cooling, the mold is demoulded to obtain a periodic continuous microstructure; Use a conventional laser cutting machine or diamond tool to micro-cut the periodic continuous microstructure, and control the size deviation of the microstructure after cutting to be between ±5μm and ±20μm. Check the protrusion surface after cutting, wherein the microstructure adopts a continuous large-pitch elliptical cylindrical lens; The light guide plate and the periodic continuous microstructure are adhered to each other with a light-transmitting adhesive, the lower end of the protrusion surface of each microstructure is attached to the light guide plate, the upper end plane is processed on the PET substrate, and the PET substrate is attached to the screen, wherein a part of the light beam in the microstructure passes through the lower convergence point and is directly transmitted from the upper end plane, and the other part of the light beam passes through the lower convergence point and is totally reflected at the edges of the protrusion surfaces on both sides of the microstructure array, and is emitted from the upper end plane of the microstructure array, and its propagation direction is regulated by the surface shape of the protrusion surface of the microstructure array, thereby forming an array light source that can emit light beams at multiple angles; A multi-view collaborative light control display algorithm is used to encode screen pixels so that the light information displayed on the screen contains spatial light field information. The light beam emitted by the continuous microstructure light source is loaded with the light information displayed on the screen, and is transmitted from the screen to multiple positions in space, and converges into a set of pixels to form a light field display.

Images