Light field 3D display and light field 3D display method

Abstract

The invention belongs to the technical field of 3D display, and relates to a light field 3D display and a light field 3D display method. The light field 3D display comprises a directional light-emitting 2D display screen used for emitting a plurality of first light rays, a cylindrical lens array used for carrying out direction modulation on the plurality of first light rays emitted by the directional light-emitting 2D display screen, and an optical diffusion screen used for carrying out small-angle diffusion on the plurality of second light rays in the one-dimensional direction; the directional light-emitting 2D display screen, the cylindrical lens array and the optical diffusion screen are sequentially arranged in a stacked mode and used for conducting direction modulation and small-angle diffusion in the one-dimensional direction on directional light rays emitted by the directional light-emitting 2D display screen so as to reconstruct a complete discrete light field, and therefore continuous 3D images are obtained. The invention further discloses a light field 3D display method. The light field 3D displayer has the advantages of being large in visual angle, high in resolution ratio, large in depth range and the like, and mutual restriction of performance parameters of a traditional light field 3D displayer is relieved.

Description

Technical Field

[0001] The present invention relates to the field of 3D display technologies, and particularly to a light field 3D display and a light field 3D display method. Background Art

[0002] Light field 3D display is a display technology that presents 3D images by reconstructing the light emission distribution of objects in free space. It can reconstruct high-dimensional light data, meet the stereoscopic vision characteristics of the human eye, correctly present the mutual occlusion relationship between different objects, and achieve a natural and comfortable stereoscopic perception effect. Resolution, viewing angle, and depth are three important performance parameters of a light field 3D display. However, the disclosed light field 3D displays cannot simultaneously achieve high resolution and a large depth range within a large viewing angle range. Due to the mutual restriction of these three performance parameters, the disclosed technical solutions usually choose to solely improve one of the performance parameters, while the other performance parameters are severely sacrificed, making it difficult to well meet the viewing and usage requirements. Summary of the Invention

[0003] The objective of the present invention is to provide a light field 3D display and a light field 3D display method, enabling the light field 3D display to simultaneously achieve high resolution and a large depth range within a large viewing angle range.

[0004] The first aspect of the present invention provides a light field 3D display, which includes: a directional light-emitting 2D display screen arranged at the bottom layer of the light field 3D display, the directional light-emitting 2D display screen being configured to emit multiple first light rays, wherein the multiple first light rays carry light field position and direction information and form a light beam with a first divergence angle; a cylindrical lens array, one side of the cylindrical lens array being attached to the surface of the directional light-emitting 2D display screen and arranged to be inclined relative to the directional light-emitting 2D display screen, wherein the cylindrical lens array is configured to perform direction modulation on the multiple first light rays emitted by the directional light-emitting 2D display screen to form multiple second light rays that reconstruct a discrete light field; an optical diffuser screen arranged on the other side of the cylindrical lens array, the optical diffuser screen being configured to diffuse the multiple second light rays along a one-dimensional direction into a light beam with a second divergence angle, so that the 3D image corresponding to the discrete light field in space becomes continuous.

[0005] In some examples, the first divergence angle is selected from any one of ±2°, ±3°, and ±5°, and the second divergence angle is selected from any one of 3.5°, 5°, and 6.5°.

[0006] In some examples, the light-emitting type of the directional light-emitting 2D display screen is the passive light-emitting type. The passive light-emitting type directional light-emitting 2D display screen includes: a backlight module, the backlight module includes a light source layer, a microlens array, and a free-form surface lens array arranged in sequence, wherein the lens units in the microlens array have a surface type selected from any one of a free-form surface and an aspherical surface, and the lens units in the free-form surface lens array are selected from any one of a free-form surface lens and a free-form surface Fresnel lens; a liquid crystal panel, the liquid crystal panel includes a plurality of sub-pixels arranged in a rectangular strip shape, and each of the plurality of sub-pixels has a color selected from any one of red, green, blue, and white, wherein a plurality of sub-pixels of different colors form a single color pixel of the liquid crystal panel.

[0007] In some examples, the light-emitting type of the directional light-emitting 2D display screen is the active light-emitting type. The active light-emitting type directional light-emitting 2D display screen includes: a display layer, the display layer is provided with a plurality of sub-pixels, and the sub-pixels achieve active light emission by electro-luminescence or inorganic semiconductors, wherein each of the plurality of sub-pixels has a color selected from any one of red, green, blue, and white, and a plurality of sub-pixels of different colors form a single color pixel of the display layer; a light beam pointing layer, the light beam pointing layer is integrated on one side of the light-emitting surface of the display layer, and includes a microlens array and a free-form surface lens array arranged in sequence, wherein the lens units in the microlens array and the free-form surface lens array are arranged corresponding to a plurality of pixels or a single pixel of the display layer.

[0008] In some examples, the cylindrical lens array is formed by arranging a plurality of cylindrical lens units at equal intervals in a one-dimensional direction, wherein the cross-sectional surface type of the cylindrical lens unit is a free-form surface or an aspherical surface.

[0009] In some examples, the modulation function distribution of the optical diffusion screen for the light intensity is a Gaussian distribution or a flat-top distribution, wherein the diffusion direction of the optical diffusion screen for diffusing the plurality of second light rays is consistent with the arrangement direction of the cylindrical lens units on the cylindrical lens array.

[0010] The second aspect of the present invention provides a light field 3D display method, including: emitting a plurality of first light rays through a directional light-emitting 2D display screen, where the plurality of first light rays form a light beam with a first divergence angle, and the first divergence angle is selected from any angle of ±2°, ±3°, ±5°; performing direction modulation on the plurality of first light rays emitted by the directional light-emitting 2D display screen through a cylindrical lens array, and converging the plurality of first light rays to the focal position of each cylindrical lens unit constituting the cylindrical lens array to form a plurality of second light rays for reconstructing a discrete light field, where the cylindrical lens array is inclined with respect to the directional light-emitting 2D display screen, and the cylindrical lens array is formed by arranging a plurality of cylindrical lens units at equal intervals in one dimension; diffusing the plurality of second light rays into a light beam with a second divergence angle along one dimension through an optical diffusing screen, so that the 3D image corresponding to the discrete light field in space becomes continuous, where the diffusing direction of the optical diffusing screen for diffusing the plurality of second light rays is the same as the arrangement direction of the cylindrical lens units on the cylindrical lens array.

[0011] In some examples, the image spot width on the incident light surface of the optical diffusing screen is smaller than the sub-pixel width of the directional light-emitting 2D display screen, and the direction of the image spot width on the incident light surface of the optical diffusing screen is the same as the array direction of the cylindrical lens array; the image spot width on the outgoing light surface of the optical diffusing screen is less than or equal to the pitch of the cylindrical lens array, and the direction of the image spot width on the outgoing light surface of the optical diffusing screen is the same as the array direction of the cylindrical lens array.

[0012] In some examples, the directional light-emitting 2D display screen loads a 3D video source, the resolution of the 3D video source is the same as the resolution of the directional light-emitting 2D display screen, the 3D video source includes several sub-pixel combinations with different intensity values, and the light rays formed by the several sub-pixel combinations respectively converge at a preset specified distance to form several viewpoints, and the viewpoints are arranged in an equally spaced array; the distance between adjacent viewpoints is less than the average pupil diameter, so that the pupil obtains depth cues for monocular focus adjustment by simultaneously receiving information from at least two viewpoints.

[0013] In some examples, a single light ray corresponding to each viewpoint and traversing all the viewpoints together divides the sub-pixels into several image elements; each image element is correspondingly arranged with at least two cylindrical lens units in the array direction of the cylindrical lens array, and each image element is correspondingly arranged with at least two rows of pixels or at least two columns of sub-pixels of the directional light-emitting 2D display screen in the direction perpendicular to the array of the cylindrical lens array; each sub-pixel of the image element is arranged at different distances from the same edge of the corresponding cylindrical lens unit.

[0014] In the light field 3D display of the present invention, the bottommost directional light-emitting 2D display screen emits light rays with an extremely small divergence angle, high directivity, and high uniformity. The light rays carry the position and direction information of the light field. After the direction of the light rays is modulated by each cylindrical lens unit of the cylindrical lens array, they converge to the focal position of each cylindrical lens unit, and then are diffusely scattered at a small angle in one dimension by the optical diffusing screen. The light rays from different directions and carrying the information of the same 3D image point converge at the reproduction position corresponding to the 3D image point, reconstructing a complete discrete light field. Finally, the light rays continue to propagate forward, forming a 3D display effect with a large viewing angle, high resolution, and a large depth range. Among them, the cylindrical lens array can deflect the light rays over a large range to a specified position in space, thereby achieving a large viewing angle range; and the cylindrical lens array precisely modulates the direction of the light rays, making the one-dimensional size of the 3D image point along the direction of the cylindrical lens unit array less than or equal to the pitch of the cylindrical lens array, ensuring high resolution and a large depth range. Among them, the optical diffusing screen diffusely scatters the light rays modulated by the cylindrical lens array at a small angle in one dimension, so that the 3D image is visually continuous without obvious breaks or discontinuities. The light field 3D display of the present invention constructs a large number of dense viewpoints. A single eye can simultaneously receive information from no less than two viewpoints, ensuring that the human eye can correctly perceive the stereoscopy within the viewing angle range by means of monocular focus adjustment, monocular motion parallax, and binocular parallax cues. The light field 3D display of the present invention realizes the effects of high resolution and a large depth range simultaneously within a large viewing angle range through the cooperative arrangement of the directional light-emitting 2D display screen, the cylindrical lens array, and the optical diffusing screen, alleviating the mutual restriction of the performance parameters of resolution - viewing angle - depth in traditional light field 3D displays. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] The foregoing aspects and advantages of the present invention will be further clarified and easily understood from the following detailed description in conjunction with the drawings and embodiments, where:

[0016] Figure 1 is a perspective view of the internal structure of a light field 3D display according to an embodiment of the present invention;

[0017] Figure 2 is a perspective view of the internal structure of the directional light-emitting 2D display screen according to an embodiment of the present invention;

[0018] Figure 3 is a side view of the internal structure of the backlight module according to an embodiment of the present invention;

[0019] Figure 4 is a side view of the liquid crystal panel modulating light rays according to an embodiment of the present invention;

[0020] Figure 5 is a top view of the cylindrical lens array placed obliquely relative to the directional light-emitting 2D display screen according to an embodiment of the present invention;

[0021] Figure 6 It is a side view of the reconstructed discrete light field distribution of a light field 3D display according to an embodiment of the present invention;

[0022] Figure 7 It is a side view of the viewpoint arrangement according to an embodiment of the present invention;

[0023] Figure 8A It is a side view of the correspondence between a single viewpoint and sub - pixels according to an embodiment of the present invention;

[0024] Figure 8B It is a schematic diagram of sub - pixels included in a single image element according to an embodiment of the present invention;

[0025] Figure 9 It is a top view of the correspondence between image elements and lenticular lens units according to an embodiment of the present invention;

[0026] Figure 10 It is a side view of the viewing angle range according to an embodiment of the present invention;

[0027] Figure 11A It is the depth z according to an embodiment of the present invention 1 Side view of the light received by viewer I at the position;

[0028] Figure 11B It is the depth z according to an embodiment of the present invention 2 Side view of the light received by viewer II at the position.

[0029] It should be understood that the above - mentioned drawings are only schematic and are not drawn to scale. Detailed implementation manners

[0030] The following details an embodiment of a light field 3D display and a light field 3D display method proposed by the present invention, and further describes the present invention. The following embodiments are only used to further illustrate the present invention and should not be construed as limiting the protection scope of the present invention. Those skilled in the art can make some non - essential improvements and adjustments to the present invention based on the above - mentioned invention content, and still fall within the protection scope of the present invention.

[0031] The first aspect of the present invention provides a light field 3D display. As Figure 1As shown, the light field 3D display includes a directional emission 2D display screen 100, a cylindrical lens array 200, and an optical diffuser screen 300. According to some embodiments of the light field 3D display of the present invention, the directional emission 2D display screen 100 is arranged at the bottom layer of the light field 3D display, and the directional emission 2D display screen 100 is configured to emit multiple first light rays, wherein the multiple first light rays form a light beam with a first divergence angle; the cylindrical lens array 200 is arranged with one side attached to the surface of the directional emission 2D display screen 100 and is placed obliquely with respect to the directional emission 2D display screen 100, wherein the cylindrical lens array 200 is configured to perform direction modulation on the multiple first light rays emitted by the directional emission 2D display screen 100 to form multiple second light rays that reconstruct a discrete light field; the optical diffuser screen 300 is arranged on the other side of the cylindrical lens array 200, and the optical diffuser screen 300 is configured to diffuse the multiple second light rays along a one-dimensional direction into a light beam with a second divergence angle, so that the 3D image corresponding to the discrete light field in space becomes continuous. In some examples, the second divergence angle of the light beam diffused along the one-dimensional direction can be 3.5°, 5°, 6.5°, and preferably, the second divergence angle is 5°. Thus, the light rays emitted by the directional emission 2D display screen 100 are directionally modulated by the cylindrical lens array 200 and the optical diffuser screen diffusely scatters the directionally modulated light rays at a small angle along a one-dimensional direction, so that the light rays finally exit from the optical diffuser screen and are received by the human eye, forming a 3D display effect with a large viewing angle, high resolution, and a large depth range.

[0032] Figure 1 The embodiment of the light field 3D display shown demonstrates that the directional emission 2D display screen 100 is arranged at the bottom layer of the light field 3D display, the cylindrical lens array 200 is arranged at the middle layer of the light field 3D display, and the optical diffuser screen 300 is arranged at the upper layer of the light field 3D display, thereby modulating the light rays emitted by the light source in sequence. However, those skilled in the art should understand that Figure 1 The stacked structure in which the directional emission 2D display screen 100, the cylindrical lens array 200, and the optical diffuser screen 300 of the light field 3D display shown are arranged in sequence from bottom to top is only exemplary, and the directional emission 2D display screen 100, the cylindrical lens array 200, and the optical diffuser screen 300 can also be arranged in sequence in other directional orders. For example, the directional emission 2D display screen 100, the cylindrical lens array 200, and the optical diffuser screen 300 can be stacked and arranged in sequence from left to right or from right to left.

[0033] In some embodiments, the directional light-emitting 2D display screen 100 is a highly directional light-emitting 2D display screen, which is capable of emitting a directional light beam with an extremely small divergence angle, that is, multiple first light rays emitted by the highly directional light-emitting 2D display screen have a high degree of directivity and almost propagate along a specific direction with a very small divergence angle. In some examples, the divergence angle can be ±2°, ±3°, or ±5°. Each light ray emitted by each pixel or sub-pixel of such a highly directional light-emitting 2D display screen carries the position and direction information of the light field, so as to be able to accurately represent the light field information.

[0034] In some embodiments, the light-emitting type of the directional light-emitting 2D display screen 100 can be a passive light-emitting type or an active light-emitting type.

[0035] Figure 2 The internal structure of the directional light-emitting 2D display screen 100 with a passive light-emitting type is shown. As shown in the figure, some examples of the directional light-emitting 2D display screen 100 can be liquid crystal display screens, including a backlight module 110 and a liquid crystal panel 120. The smallest light-emitting unit of the directional light-emitting 2D display screen 100 is formed by sub-pixels 130 on the liquid crystal panel 120, where multiple sub-pixels 130 are arranged in a rectangular strip on the liquid crystal panel 120, and multiple sub-pixels 130 of different colors constitute a single color pixel. In some examples, the color of the sub-pixel 130 is red (R), green (G), and blue (B), that is, the composition of each pixel is the RGB sub-pixel arrangement type. In some alternative examples, the color of the sub-pixel 130 can also be red (R), green (G), blue (B), and white (W), that is, the composition of each pixel is the RGBW sub-pixel arrangement type.

[0036] In some embodiments, the backlight module 110 adopts a directional backlight module, which is used to emit backlight with high directivity, small divergence angle, and high uniformity. The light-emitting direction is the direction orthogonal to the plane of the backlight module 110. The divergence angle of the light beam can be ±2°, ±3°, or ±5°, and the uniformity of the light beam can be 90%, 95%, or 98%. As Figure 3 shown, the backlight module 110 includes a light source layer 111, a microlens array 112, and a free-form lens array 113. The light source layer 111, the microlens array 112, and the free-form lens array 113 are stacked in sequence from bottom to top. Of course, Figure 3The light source layer 111, the microlens array 112, and the free-form lens array 113 shown are stacked in sequence from bottom to top, which is only exemplary. The light source layer 111, the microlens array 112, and the free-form lens array 113 can be arranged in sequence in other directions (such as from left to right or from right to left). In some examples, the light source layer 111 includes but is not limited to white light MiniLEDs and white light LED arrays. In some examples, the surface type of the lens units in the microlens array 112 includes but is not limited to free-form surfaces and aspherical surfaces, which are used to homogenize the light emitted by the light source layer 111. In some examples, the surface type of the lens units in the free-form lens array 113 includes but is not limited to free-form surfaces and free-form Fresnels, which are used to collimate the light passing through the microlens array 112, so as to finally collimate the large-angle scattered light into a small-angle light beam, and the small-angle light beam is within ±2°, ±3°, ±5° as described above.

[0037] As Figure 4 As shown, the liquid crystal panel 120 is used to change the light transmittance of the light emitted from the backlight module 110 and modulate the light intensity. The highly directional, small divergence angle, and high uniformity light emitted by the backlight module 110 is projected onto the liquid crystal panel 120, and the liquid crystal panel 120 is loaded with a 3D video source recording light field information. The light modulated by the liquid crystal panel 120 is also highly directional, and the divergence angle is affected by the scattering characteristics of the liquid crystal material and is slightly larger than the divergence angle of the light beam of the backlight module 110. For example, it is ±2.5°, ±3.5°, ±5.5°. The modulated light carries the position and angle information of the light field.

[0038] In some examples, the resolution of the liquid crystal panel 120 ≥ 1920×1080 pixels. For example, it is 1920×1080 pixels, 2460×1080 pixels, 3840×2160 pixels, 7680×4320 pixels, 15360×8640 pixels. In some examples, the size of the liquid crystal panel 120 ≥ 6 inches. For example, it is 6.8 inches, 10.1 inches, 15.6 inches, 27 inches, 31.5 inches. In some examples, the pixel density of the liquid crystal panel 120 can be 279PPI, 396PPI, 403PPI, 653PPI.

[0039] In an embodiment where the light-emitting type of the directional light-emitting 2D display screen 100 is the active light-emitting type, the directional light-emitting 2D display screen 100 includes a display layer and a light beam directing layer. The display layer is used to display an image and emits light rays with a large diffusion angle. The light beam directing layer is integrated on the light-emitting surface side of the display layer and is used to converge, direct, collimate, and homogenize the light rays, achieving high directivity, an extremely small divergence angle, and high uniformity. The divergence angle of the light beam can be ±2°, ±3°, or ±5°, and the uniformity of the light beam can be 90%, 95%, or 98%.

[0040] In some examples, the display layer is selected from any one of an LED display panel, a MicroLED display panel, an AMOLED panel, or an OLED display panel with a relatively small arrangement pitch of pixel units. Each sub-pixel constituting the display layer realizes active light emission by electro-luminescence or an inorganic semiconductor, and there is no need to additionally configure a backlight module. A plurality of sub-pixels are arranged periodically on the display layer, and a plurality of sub-pixels of different colors constitute a single color pixel. In some examples, the color of the sub-pixel is red (R), green (G), and blue (B), that is, the composition of each pixel is the RGB sub-pixel arrangement type. In some alternative examples, the color of the sub-pixel can also be red (R), green (G), blue (B), and white (W), that is, the composition of each pixel is the RGBW sub-pixel arrangement type.

[0041] In some examples, the light beam directing layer is integrated on the light-emitting surface side of the display layer and includes Figure 3 the microlens array 112 and the free-form lens array 113 as shown. And as described above, the microlens array 112 and the free-form lens array 113 form a two-stage optical modulation structure. In some examples, the microlens array 112 is formed by regularly arranging a plurality of lens units, and the lens units can correspond to multiple pixels or a single pixel of the display layer. In some examples, the free-form lens array 113 is formed by regularly arranging a plurality of free-form lens units, and the free-form lens units can correspond to multiple pixels or a single pixel of the display layer.

[0042] Figure 5 It shows that the cylindrical lens array is placed obliquely relative to the directional light-emitting 2D display screen according to an embodiment of the present invention. As shown in the figure, the cylindrical lens array 200 is closely attached to the surface of the directional light-emitting 2D display screen 100, that is, the surface of the liquid crystal panel 120, and forms an inclination angle q with the directional light-emitting 2D display screen 100. The range of the inclination angle q is -45° ≤ q < 0° or 0° < q ≤ 45°. The cylindrical lens array 200 has an inclination angle relative to the pixel columns of the directional light-emitting 2D display screen 100, which is beneficial to avoiding moiré fringes and expanding the viewing angle. The alignment accuracy between the cylindrical lens array 200 and the directional light-emitting 2D display screen 100 is determined by the bonding accuracy and the software image correction algorithm.

[0043] In some embodiments, the cylindrical lens array 200 is formed by arranging a plurality of cylindrical lens units 210 at equal intervals in a one-dimensional direction. In some examples, this one-dimensional direction can be the horizontal direction along the x-axis or the vertical direction along the y-axis. Figure 5 The shown cylindrical lens array 200 shows that a plurality of cylindrical lens units 210 are arranged at equal intervals in the horizontal direction along the x-axis. In some embodiments, the number of sub-pixels covered by a single cylindrical lens unit 210 in the horizontal direction along the x-axis is ≥10, for example, 18.

[0044] In some embodiments, the cylindrical lens array 200 is formed in one processing step. The cross-sectional surface shape of the cylindrical lens unit 210 can be any one of a free surface (such as an XY polynomial surface) or an aspherical surface (such as an even polynomial surface) to eliminate aberration. For example, the surface shape of the cylindrical lens unit 210 is an even rotationally symmetric aspherical surface with a maximum order of 32. The cylindrical lens array 200 deflects and modulates the directional light incident from the directional emission 2D display screen 100 through the curved surface optical characteristics of the cylindrical lens unit 210, so that the light rays from different sub-pixels are emitted at a preset angle, and a discrete light field distribution is reconstructed in space. In the cylindrical lens array 200 according to the embodiments of the present invention, multiple light beams carrying the information of the same 3D object point are modulated by different cylindrical lens units 210 and then converge and reconstruct into a 3D image point at a predetermined depth position. At the same time, the cooperative action of multiple adjacent cylindrical lens units expands the viewing angle; the cylindrical lens array 200 is arranged obliquely with the directional emission 2D display screen 100 to suppress moiré fringes, and the surface shape of each cylindrical lens unit adopts an aspherical surface or a free surface to eliminate aberration, creating conditions for realizing light field 3D display with high resolution, large viewing angle and large depth range.

[0045] Such as Figures 6 to 11B As shown, the optical diffusing screen 300 can diffusely scatter the reconstructed light rays modulated by the cylindrical lens array 200 at a small angle in a one-dimensional direction, making the 3D image corresponding to the discrete light field continuous. In some embodiments, the modulation function distribution of the optical diffusing screen 300 for light intensity is a Gaussian distribution or a flat-top distribution, and it has a diffusion angle only in a one-dimensional direction. For example, the diffusion angle can be 3.5°, 5°, 6.5°, etc. Similarly, the one-dimensional diffusion of the optical diffusing screen 300 for light rays can be any one of the horizontal direction along the x-axis and the vertical direction along the y-axis. In some examples, the light ray diffusion direction of the optical diffusing screen 300 is consistent with the direction of the equal interval arrangement of the cylindrical lens units 210.

[0046] An embodiment will be used below to exemplarily illustrate the functional principle of the optical diffusing screen 300, in which the cylindrical lens units 210 in the cylindrical lens array 200 are arranged in a one-dimensional horizontal direction, and the optical diffusing screen 300 diffuses the light incident through the cylindrical lens array 200 in the one-dimensional horizontal direction. The light rays modulated by the cylindrical lens array 200 are discretely distributed (similar to a dot matrix), and there are tiny gaps between adjacent 3D image points. When directly displayed, the human eye will perceive that the image is composed of countless separated light points, similar to the "pixel granularity" of a low-resolution display screen. The optical diffusing screen 300 according to the embodiment of the present invention diffuses the light rays at a small angle in the horizontal arrangement direction of the cylindrical lens units, while remaining unchanged in the vertical direction. The small-angle horizontal diffusion eliminates the gaps between adjacent 3D image points, eliminates the discrete feeling, and at the same time avoids excessive blurring. Without diffusion in the vertical direction, the original resolution is maintained, and image blurring is avoided. Thus, through the further processing of the optical diffusing screen 300, the presentation of the 3D image corresponding to the discrete light field becomes continuous.

[0047] Therefore, after the propagation directions of multiple highly directive light rays emitted by the directive light-emitting 2D display screen 100 are modulated by each cylindrical lens unit 210 of the cylindrical lens array 200, they converge to the focal position of each cylindrical lens unit 210. After passing through the optical diffusing screen 300, they are diffused at a small angle in the horizontal direction and continue to propagate forward. When the light rays converge to the focal position of the cylindrical lens unit 210, the average horizontal dimension of the image spot projected onto the lower surface of the optical diffusing screen 300 on the x-axis is 0.01 mm, which is smaller than the horizontal dimension of a single sub-pixel. After being diffused by the optical diffusing screen 300, the horizontal dimension of the image spot on the x-axis expands and is smaller than the pitch of the cylindrical lens array 200, thereby achieving high resolution and a large depth range.

[0048] The second aspect of the present invention provides a light field 3D display method, including emitting multiple first light rays through the directive light-emitting 2D display screen 100, where the multiple first light rays form a light beam with a first divergence angle; modulating the directions of the multiple first light rays emitted by the directive light-emitting 2D display screen 100 through the cylindrical lens array 200, and converging the multiple first light rays to the focal position of each cylindrical lens unit 210 that makes up the cylindrical lens array 200 to form multiple second light rays that reconstruct a discrete light field; diffusing the multiple second light rays into a light beam with a second divergence angle along a one-dimensional direction through the optical diffusing screen 300, so that the 3D image corresponding to the discrete light field in space becomes continuous, where the second divergence angle is 3.5°, 5°, 6.5°, and preferably, the second divergence angle is 5°.

[0049] In some embodiments, after the direction of the light emitted by the directional light-emitting 2D display screen 100 is modulated by the cylindrical lens array 200, it is accurately converged to the focal position of each cylindrical lens unit 210, and the image spot size is small. Subsequently, after passing through the optical diffuser screen 300, it is diffused at a small angle in one dimension and continues to propagate forward. The light rays from different directions and carrying the information of the same 3D image point converge at the reproduction position corresponding to the 3D image point and continue to propagate forward to reconstruct a complete discrete light field. The light field is first discretely reconstructed and then directly perceived by a single eye. For a 3D image point, the single eye receives no less than two light rays from different directions, providing depth cues for single-eye focus adjustment. In some embodiments, the width of the image spot on the incident light surface of the optical diffuser screen 300 is smaller than the width of the sub-pixel 130 of the directional light-emitting 2D display screen 100, and the direction of the width of the image spot on the incident light surface of the optical diffuser screen 300 is the same as the array direction of the cylindrical lens array 200; the width of the image spot on the light-emitting surface diffused by the optical diffuser screen 300 is less than or equal to the pitch of the cylindrical lens array 200, and the direction of the width of the image spot on the light-emitting surface of the optical diffuser screen 300 is the same as the array direction of the cylindrical lens array 200. In other words, the light rays converge to the focal position of each cylindrical lens unit 210, and the one-dimensional size of the image spot projected onto the lower surface of the optical diffuser screen 300 along the direction of the equal-spacing arrangement of the cylindrical lens units 210 is smaller than the one-dimensional size of a single sub-pixel 130 along the same direction, and after being diffused by the optical diffuser screen 300, the one-dimensional size of the image spot along the direction of the equal-spacing arrangement of the cylindrical lens units 210 is less than or equal to the pitch of the cylindrical lens array 210.

[0050] In some embodiments, as Figure 7 shown, the directional light-emitting 2D display screen 100 loads a 3D video source, and the resolution of the 3D video source is the same as that of the directional light-emitting 2D display screen 100. The 3D video source includes a combination of a number of sub-pixels 130 with different intensity values. The light rays formed by the combination of a number of sub-pixels 130 converge respectively at a preset specified distance to form a number of viewpoints 710, and the viewpoints 710 are arranged in an equal-spacing array; the distance between adjacent viewpoints 710 is smaller than the average aperture of the pupil, so that the pupil obtains depth cues for single-eye focus adjustment because it receives information from no less than two viewpoints 710 at the same time. Each single light ray corresponding to each viewpoint 710 and traversing all viewpoints 710 together divides the sub-pixels 130 into a number of image elements 810; each image element 810 is correspondingly arranged with at least two cylindrical lens units 210 in the array direction of the cylindrical lens array 200; each image element 810 is correspondingly arranged with at least two rows of pixels or at least two columns of sub-pixels of the directional light-emitting 2D display screen 100 in the direction perpendicular to the array of the cylindrical lens array 200; each sub-pixel 130 of the image element 810 is arranged at different distances from the same edge of the corresponding cylindrical lens unit 210.

[0051] Alternatively, the 3D video source is encoded with the position and direction information of the light field collected at different viewpoints, and is presented as a combination of sub-pixels 130 with different intensity values. Each sub-pixel 130 corresponds to a ray of light propagating in a certain direction of the light field. A group of rays of light that converge to a point at a preset specified distance form a viewpoint 710, and the viewpoints 710 are arranged at equal intervals in a one-dimensional direction. Taking one ray of light corresponding to each viewpoint 710 and traversing all viewpoints 710, a group of rays of light is obtained, and all sub-pixels 130 corresponding to the group of rays of light form an image element 810. In the direction along which the lenticular lens units 210 are arranged at equal intervals, each image element 810 corresponds to multiple lenticular lens units 210, and in the direction perpendicular to the direction in which the lenticular lens units 210 are arranged at equal intervals, it includes multiple rows or columns of pixels or sub-pixels 130. In the image element 810, each sub-pixel 130 has a different positional relationship with the same edge of the lenticular lens unit 210 corresponding to it. The number of sub-pixels 130 included in each image element 810 is the same as the total number of viewpoints 710.

[0052] Alternatively, the one-dimensional distance between adjacent viewpoints 710 is less than the average pupil diameter of a single eye. A single eye can simultaneously receive information from no less than two viewpoints 710 and has depth cues for single-eye focus adjustment.

[0053] In some examples, in the direction along which the lenticular lens units 210 are arranged at equal intervals, the number of lenticular lens units 210 corresponding to each image element 810 is ≥ 2.

[0054] In some examples, in the direction perpendicular to the direction in which the lenticular lens units 210 are arranged at equal intervals, the number of rows or columns of sub-pixels 130 or pixels included in each image element 810 is ≥ 2 rows or 2 columns.

[0055] In some examples, the video loaded on the directional light-emitting 2D display screen 100 is continuously synthesized from multiple frames of images, and each frame of image is a 3D video source.

[0056] Figure 6This is a side view of the reconstructed discrete light field distribution for the light field 3D display according to an embodiment of the present invention. Taking the object point S as an example, its corresponding 3D image point is S'620. Multiple sub-pixels 130-1, 130-2, 130-3, and 130-4 that carry the position and direction information of the light rays emitted by the object point S emit light rays. After modulation, four reconstructed light rays 620-1, 620-2, 620-3, and 620-4 with different directions are obtained. They converge at the 3D image point S'620 and continue to propagate forward, reconstructing the discrete light emission distribution on the surface of the 3D image point S'620, which is then directly perceived by a single eye. The reconstructed light rays 620-3 and 620-4 enter the left eye 630-1, and the reconstructed light rays 620-1 and 620-2 enter the right eye 630-2. For the 3D image point S'620, a single eye receives two light rays from different directions, providing depth cues for monocular focus adjustment.

[0057] Figure 7 This is a side view of the view point arrangement according to an embodiment of the present invention. The view points 710 are evenly and densely arranged at equal intervals in the one-dimensional horizontal direction. At a preset specified distance, the distance between adjacent view points 710 is less than the average pupil diameter of 3.0 mm of the left eye 630-1 or the right eye 630-2. The left eye 630-1 simultaneously receives the information of view points 710-1 and 710-2, and the right eye 630-2 simultaneously receives the information of view points 710-3 and 710-4, having depth cues for monocular focus adjustment. The difference in the view point indices received by the left eye 630-1 and the right eye 630-2 is ≥ 2, for example, 3. All the view points form a viewing area, and in this viewing area, one or more people can simultaneously view the correct 3D image.

[0058] Figure 8A This is a side view of the correspondence between a single view point and sub-pixels according to an embodiment of the present invention. Sub-pixels 130 with different intensity values are combined into an image loaded on the directional emission 2D display screen 100, specifically a 3D video source. The resolution of the 3D video source is exactly the same as that of the directional emission 2D display screen 100, for example, 1920×1080 pixels, 2460×1080 pixels, 3840×2160 pixels, 7680×4320 pixels, 15360×8640 pixels, etc. The 3D video source is encoded from the position and direction information of the light field collected at different view points. Each sub-pixel 130 of the 3D video source corresponds to a light ray propagating along a certain direction of the light field, and a group of light rays converging at a point at a preset specified distance constitutes a view point. For example, Figure 8A in it, sub-pixels 130-5, 130-6, 130-7, and 130-8 respectively correspond to the reconstructed light rays 620-5, 620-6, 620-7, and 620-8 propagating along the light field direction, and these four light rays constitute the view point 710-4.

[0059] Figure 8BSchematic diagram of sub-pixels included in a single image element according to an embodiment of the present invention. Take a ray corresponding to each viewing point, and traverse all viewing points. For example, take 12 rays corresponding to viewing points 710-1 to 710-12 respectively, to obtain a set of rays. Two rows of sub-pixels 130-5 and 130-9 to 130-19 corresponding to this set of rays together form an image element 810. In the 3D video source, the image elements 810 are arranged periodically.

[0060] Figure 9 Top view of the corresponding relationship between the image element and the lenticular lens unit according to an embodiment of the present invention. The image element 810 corresponds to 6 lenticular lens units 210 in the horizontal direction along the x-axis, and a total of 112 sub-pixels are included. In the vertical direction along the y-axis, it includes 2 rows of pixels, and the total number of sub-pixels included is 222, which is the same as the total number of viewing points. In the image element 810, each sub-pixel 130 has a different positional relationship with the left edge of its corresponding lenticular lens unit 210, corresponding to the rays forming different viewing points. For example, the offsets of sub-pixels 130-13 and 130-20 from their respective corresponding lenticular lens units 210-1 and 210-2 are different, corresponding to the rays forming viewing points 99 and 64 respectively.

[0061] Figure 10 Side view of the viewing angle range according to an embodiment of the present invention. Among the 6 lenticular lens units 210 covered by a single image element 810 in the one-dimensional horizontal direction, the two sub-pixels 130-21 and 130-22 that are farthest and closest to the left edge of the lenticular lens unit 210 emit highly directive rays. After being directionally modulated by different two lenticular lens units 210-2 and 210-3 and diffusely scattered in the one-dimensional horizontal direction by the optical diffuser screen 300 respectively, they are respectively modulated to the left edge direction 1010-1 and the right edge direction 1010-2. The included angle formed by the direction 1010-1 and the direction 1010-2 along the optical diffuser screen 300 is the viewing angle of the light field 3D display. Different side information of the object can be viewed at different angular positions within this viewing angle range, providing monocular motion parallax and binocular parallax cues at the same time.

[0062] FIG. 11 is a side view of a viewer receiving reconstructed rays at different depth positions according to an embodiment of the present invention. The sub-pixels of the directive light-emitting 2D display screen 100 have a certain size. The sub-pixels 130-1, 130-2, 130-3, and 130-4 carry the light field information of the same object point S. The highly directive rays emitted by these four sub-pixels converge at the focal points 610 of each lenticular lens unit of the lenticular lens array 200, and continue to propagate forward. After being diffusely scattered in the one-dimensional horizontal direction by the optical diffuser screen 300, a certain range of reconstructed rays is obtained. The intersection area of the reconstructed rays is the reconstruction area 1110 of the 3D image point S'. Figure 11A Depth z according to an embodiment of the present invention 1Side view of the light received by viewer I at a position. At this time, the left eye 630-1 receives the reconstructed light rays 620-3 and 620-4, and the right eye 630-2 receives the reconstructed light rays 620-1 and 620-2. The 4 reconstructed light rays correspond to the reconstructed 3D image point S'620. Figure 11B is the depth z of the embodiment of the present invention 2 Side view of the light received by viewer II at a position. At this time, the left eye 630-3 of viewer II can receive the reconstructed light rays 621-3 and 621-4, and the right eye 630-4 receives the reconstructed light rays 621-1 and 621-2. The 4 reconstructed light rays correspond to the reconstructed 3D image point S'621. Both 3D image points S'620 and 621 are located within the reconstruction area 1110 of the 3D image point S', and both carry the information of the 3D image point S'. Regardless of whether the viewer is at the depth z 1 or z 2 position, a single eye can receive two reconstructed light rays from the 3D image point S' in different directions. Therefore, the invented light field 3D display has no viewing distance limit, can satisfy viewing at any distance such as close viewing and far viewing, and can simultaneously satisfy correct viewing by multiple people.

[0063] A light field 3D display and a light field 3D display method proposed by the present invention have the advantages of large viewing angle, high resolution, large depth range, etc., have no viewing distance limit, can satisfy viewing by multiple people at the same time, ensure that the human eye correctly perceives the three-dimensionality within the viewing angle range, and at the same time, with the help of monocular focus adjustment, monocular motion parallax and binocular parallax cues. In addition, the light field 3D display of the present technical solution uses a directional light-emitting 2D display screen, a cylindrical lens array and an optical diffusing screen to achieve a high degree of integration of the device.

[0064] In this article, the terms "including", "comprising" or any other variant thereof are intended to cover non-exclusive inclusion. In addition to the listed elements, other elements not expressly listed may also be included.

[0065] In this article, the front, back, up, down, left, right and other orientation words are defined based on the positions of the components in the drawings and the positions of the components relative to each other, only for the sake of clarity and convenience of expressing the technical solution. It should be understood that the use of the orientation words should not limit the scope of protection claimed in this application.

[0066] The above-disclosed are only the preferred embodiments of the present invention, and the scope of the patent protection of the present invention cannot be limited by this. Therefore, equivalent changes made according to the scope of the patent application of the present invention still fall within the scope of protection covered by the present invention.

Claims

1. A light field 3D display, characterized in that: include: A directional light-emitting 2D display screen arranged at a bottom layer of the light field 3D display, wherein the directional light-emitting 2D display screen is configured to emit a plurality of first light rays, wherein the plurality of first light rays carry light field position and direction information and form a light beam with a first divergence angle; A cylindrical lens array, one side of which is attached to the surface of the directional light-emitting 2D display screen and arranged to be tilted relative to the directional light-emitting 2D display screen, wherein the cylindrical lens array is configured to modulate the directions of the plurality of first light rays emitted by the directional light-emitting 2D display screen to form a plurality of second light rays for reconstructing a discrete light field; An optical diffusion screen is arranged on the other side of the cylindrical lens array, and is configured to diffuse the plurality of second light rays into light beams with a second divergence angle along a one-dimensional direction, so that a 3D image corresponding to the discrete light field in space becomes continuous.

2. The light field 3D display according to claim 1, characterized in that: The first divergence angle is selected from any angle of ±2°, ±3°, and ±5°, and the second divergence angle is selected from any angle of 3.5°, 5°, and 6.5°.

3. The light field 3D display according to claim 1, characterized in that: The directional luminous 2D display screen has a passive luminous type, and the passive luminous directional luminous 2D display screen includes: A backlight module, the backlight module comprising a light source layer, a microlens array and a free-form surface lens array arranged in sequence, wherein the lens units in the microlens array have a surface type selected from any one of a free-form surface and an aspherical surface, and the lens units in the free-form surface lens array are selected from any one of a free-form surface lens and a free-form surface Fresnel lens; A liquid crystal panel, comprising a plurality of sub-pixels arranged in rectangular strips, each of the plurality of sub-pixels having any one color selected from red, green, blue and white, wherein a plurality of sub-pixels of different colors constitute a single color pixel of the liquid crystal panel.

4. The light field 3D display according to claim 1, characterized in that: The directional luminous 2D display screen has an active luminous type, and the active luminous directional luminous 2D display screen includes: A display layer, wherein the display layer is arranged with a plurality of sub-pixels, wherein the sub-pixels are actively luminescent by electroluminescence or inorganic semiconductors, wherein each of the plurality of sub-pixels has any one color selected from red, green, blue and white, wherein a plurality of sub-pixels of different colors constitute a single color pixel of the display layer; A beam directing layer integrated on one side of the light emitting surface of the display layer, the beam directing layer comprises a microlens array and a free-form surface lens array arranged in sequence, wherein the lens units in the microlens array and the free-form surface lens array are arranged to correspond to a plurality of pixels or a single pixel of the display layer.

5. The light field 3D display according to claim 1, characterized in that: The cylindrical lens array is formed by arranging a plurality of cylindrical lens units at equal intervals in a one-dimensional direction, wherein the cross-sectional surface of the cylindrical lens units is a free-form surface or an aspherical surface.

6. A light field 3D display according to claim 5, characterized in that: The modulation function distribution of the light intensity by the optical diffusion screen is Gaussian distribution or flat-top distribution, wherein the diffusion direction of the plurality of second light rays by the optical diffusion screen is consistent with the arrangement direction of the cylindrical lens units on the cylindrical lens array.

7. A light field 3D display method, characterized in that: include: Emitting a plurality of first light rays through a directional light-emitting 2D display screen, wherein the plurality of first light rays form a light beam having a first divergence angle, and the first divergence angle is selected from any angle of ±2°, ±3°, and ±5°; Directionally modulating the plurality of first light rays emitted by the directional light-emitting 2D display screen through a cylindrical lens array, converging the plurality of first light rays to the focal position of each cylindrical lens unit constituting the cylindrical lens array, so as to form a plurality of second light rays reconstructing a discrete light field, wherein the cylindrical lens array is tilted relative to the directional light-emitting 2D display screen, and the cylindrical lens array is composed of a plurality of cylindrical lens units arranged at equal intervals in a one-dimensional direction; An optical diffuser screen is used to diffuse multiple second light rays in a one-dimensional direction into light beams with a second divergence angle, so that the 3D image corresponding to the discrete light field in space becomes continuous, wherein the diffusion direction of the multiple second light rays diffused by the optical diffuser screen is consistent with the arrangement direction of the cylindrical lens units on the cylindrical lens array.

8. The light field 3D display method according to claim 7, characterized in that: The image spot width on the light incident surface of the optical diffuser screen is smaller than the sub-pixel width of the directional light-emitting 2D display screen, and the image spot width direction on the light incident surface of the optical diffuser screen is the same as the array direction of the cylindrical lens array; the image spot width on the light exit surface of the optical diffuser screen is smaller than or equal to the pitch of the cylindrical lens array, and the image spot width direction on the light exit surface of the optical diffuser screen is the same as the array direction of the cylindrical lens array.

9. The light field 3D display method according to claim 7, characterized in that: The directional light-emitting 2D display screen is loaded with a 3D film source, the resolution of the 3D film source is the same as the resolution of the directional light-emitting 2D display screen, the 3D film source includes a plurality of sub-pixel combinations with different intensity values, and the light rays formed by the plurality of sub-pixel combinations converge at preset specified distances to form a plurality of viewpoints, and the viewpoints are arranged in an array with equal spacing; the spacing between adjacent viewpoints is smaller than the average aperture of the pupil, so that the pupil obtains depth clues for monocular focus adjustment by simultaneously receiving information from no less than two viewpoints.

10. The light field 3D display method according to claim 9, characterized in that: A single light ray corresponding to each viewpoint and traversing all the viewpoints together divides the sub-pixel into a plurality of image elements; each image element is arranged corresponding to at least two of the cylindrical lens units in the array direction of the cylindrical lens array, and each image element is arranged corresponding to at least two rows of pixels or at least two columns of sub-pixels of the directional light-emitting 2D display screen in the array vertical direction of the cylindrical lens array; each sub-pixel of the image element is arranged to have a different distance from the same edge of the corresponding cylindrical lens unit.

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