Three-dimensional display device and display driving method thereof

Abstract

The invention discloses a three-dimensional display device and a display driving method thereof. The three-dimensional display device comprises a display screen and a diffractive lens array. The display screen is used for displaying images, and each frame of image displayed by the display screen is formed by overlapping at least two sub-image frames which are switched to be displayed. The diffractive lens array is located on the light emitting side of the display screen and comprises at least four diffractive lenses with different focal lengths. The diffractive lens array is used for imaging the sub-image frames on different image planes, and the distances between the different image planes and the diffractive lens array are different, so that the depth of field of the three-dimensional display device is effectively expanded. According to the three-dimensional display device provided by the embodiment of the invention, additional polarization conversion and control elements do not need to be introduced, the complexity of the device is reduced, and the manufacturing cost is reduced.

Description

Technical Field

[0001] This application relates to the field of display technology, and in particular to a three-dimensional display device and its display driving method. Background Technology

[0002] Light field display technology is a display technology that uses ray tracing to reconstruct three-dimensional scenes in space. Light field display technology based on microlens arrays can computationally control the optical depth of reconstructed images, and is lightweight and thin, requiring no coherent light source, thus showing promising development prospects.

[0003] Light field display technology based on microlens arrays has a central depth plane in the reconstructed 3D image with optimal imaging quality. However, the image sharpness decreases rapidly as the viewing depth deviates from this central depth plane, resulting in a limited effective depth of field range and restricting the visual experience and practicality of 3D displays.

[0004] To extend depth of field, current methods employ polarization multiplexing, where microlens arrays correspond to different focal lengths under different polarization states, thus forming multiple central depth planes. These planes are then rapidly switched and fused to create high-resolution imaging ranges at different depths. However, this approach requires the introduction of additional polarization conversion and control components, increasing system complexity and manufacturing costs. Summary of the Invention

[0005] A first aspect of this application provides a three-dimensional display device, comprising: A display screen is used for image display; each frame of the image displayed on the display screen is composed of at least two sub-image frames that are switched on and overlaid; and A diffractive lens array is located on the light-emitting side of the display screen; the diffractive lens array includes at least four types of diffractive lenses with different focal lengths; the diffractive lens array is used to image each of the sub-image frames onto different image planes, and the different image planes are at different distances from the diffractive lens array.

[0006] In some embodiments, any three of the at least four diffraction lenses constitute an imaging group, which is used to image any one sub-image frame. The light emitted from the display screen includes a first wavelength, a second wavelength, and a third wavelength; the first wavelength, the second wavelength, and the third wavelength are different colors. The image plane of one type of diffractive lens in the imaging group that images the light of the first wavelength band coincides with the image plane of another type of diffractive lens that images the light of the second wavelength band, and the image plane of the third type of diffractive lens that images the light of the third wavelength band.

[0007] In some embodiments, the at least four diffraction lenses include a first lens, a second lens, a third lens, and a fourth lens; Each frame of the image displayed on the screen is composed of a first sub-image frame and a second sub-image frame superimposed on each other; The first lens, the second lens, and the third lens constitute a first imaging group; the first lens, the second lens, and the fourth lens constitute a second imaging group, or the second lens, the third lens, and the fourth lens constitute a second imaging group. The first imaging group is used to image the first sub-image frame onto a first image plane, and the second imaging group is used to image the second sub-image frame onto a second image plane.

[0008] In some embodiments, a plurality of first lenses, a plurality of second lenses, a plurality of third lenses, and a plurality of fourth lenses are arranged in multiple rows. A row of first lenses, a row of second lenses, a row of third lenses, and a row of fourth lenses are arranged sequentially to form a repeating unit. The plurality of repeating units are arranged periodically along the row or column direction of the diffraction lens array.

[0009] In some embodiments, the display screen includes a plurality of pixel units, and one diffractive lens is provided corresponding to at least one of the pixel units; Each pixel unit corresponding to the same diffraction lens emits light of different wavelengths when displaying different sub-image frames; each pixel unit corresponding to the same diffraction lens emits light of the same wavelength when displaying the same sub-pixel frame.

[0010] In some embodiments, the display screen is a field color sequence display screen, the field color sequence display screen comprising: A backlight module for providing backlight; the backlight module includes three light sources, each arranged in an array; the three light sources are respectively used to emit light in the first wavelength band, the second wavelength band, and the third wavelength band; and The display panel is located on the light-emitting side of the backlight module; the display panel includes multiple pixel units.

[0011] In some embodiments, the diffraction lens is a Fresnel zone plate, a surface relief diffraction lens, a holographic optical lens, or a superlens.

[0012] A second aspect of this application provides a display driving method for a three-dimensional display device, comprising: Receive image data; Based on the image data, the display screen is controlled to switch at least two sub-image frames for superimposed display when displaying each frame of image; In this system, different sub-image frames display the same content, and the different sub-image frames are imaged on different image planes by the diffractive lens array. The distance between the different image planes and the diffractive lens array is different.

[0013] In some embodiments, the diffraction lens array in the three-dimensional display device includes: a first lens, a second lens, a third lens, and a fourth lens; the first lens, the second lens, and the third lens constitute a first imaging group; the first lens, the second lens, and the fourth lens constitute a second imaging group, or the second lens, the third lens, and the fourth lens constitute a second imaging group; each frame of image displayed on the display screen is composed of a first sub-image frame and a second sub-image frame superimposed. The step of controlling the display screen to switch at least two sub-image frames for superimposed display when displaying each frame of image based on the image data specifically includes: During the first time period, each pixel unit corresponding to the first imaging group is controlled to display the first sub-image frame, and the first imaging group images the first sub-image frame onto the first image plane. During the second time period, each pixel unit corresponding to the second imaging group is controlled to display the second sub-image frame, and the second imaging group images the second sub-image frame onto the second image plane.

[0014] In some embodiments, each pixel unit corresponding to the same type of diffraction lens emits light of the same wavelength band within the same time period. At different times, the pixel units corresponding to the same diffraction lens emit light of different wavelengths.

[0015] This application provides a three-dimensional display device and its display driving method. The three-dimensional display device includes a display screen and a diffractive lens array. The display screen is used for image display, and each frame of the image displayed on the display screen is composed of at least two sub-image frames that are switched and superimposed. The diffractive lens array is located on the light-emitting side of the display screen and includes at least four types of diffractive lenses with different focal lengths. The diffractive lens array is used to image each of the sub-image frames onto different image planes, and the different image planes are at different distances from the diffractive lens array. According to the diffraction characteristics of the diffractive lenses, the focal length of each diffractive lens is independently designed so that any three of the at least four diffractive lenses image the three primary colors of light onto the same position, forming a colorless image plane. Any other three of the at least four diffractive lenses can image the three primary colors of light onto another position. Thus, by switching the imaging of the diffractive lenses in the diffractive lens array, at least two colorless image planes can be constructed, and the different image planes are at different distances from the diffractive lens array, thereby effectively expanding the depth of field of the three-dimensional display device. The three-dimensional display device provided in this application embodiment does not require the introduction of additional polarization conversion and control components, which reduces the complexity of the device and lowers the manufacturing cost. Attached Figure Description

[0016] To more clearly illustrate the technical solutions of the embodiments of this application, the drawings used in the embodiments of this application will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0017] Figure 1 This is a schematic diagram illustrating the imaging principle of the light field display technology provided in this application under a naked-eye 3D display architecture. Figure 2 This is a schematic diagram illustrating the imaging principle of the light field display technology provided in this application under a near-eye three-dimensional display architecture. Figure 3 This is one of the imaging quality variation curves provided in the embodiments of this application as a function of observation depth; Figure 4 This is the second example of the imaging quality variation curve with viewing depth provided in the embodiments of this application; Figure 5 This is one of the structural schematic diagrams of the three-dimensional display device provided in the embodiments of this application; Figure 6 This is the second schematic diagram of the structure of the three-dimensional display device provided in the embodiments of this application; Figure 7 This is the third schematic diagram of the structure of the three-dimensional display device provided in the embodiments of this application; Figure 8 A schematic diagram illustrating the arrangement of diffractive lenses provided in an embodiment of this application; Figure 9 Fourth schematic diagram of the structure of the three-dimensional display device provided in the embodiments of this application; Figure 10 This is one of the flowcharts of the display driving method provided in the embodiments of this application; Figure 11 This is the second flowchart of the display driving method provided in the embodiments of this application. Detailed Implementation

[0018] To make the above-mentioned objectives, features, and advantages of this application more apparent and understandable, the application will be further described below in conjunction with the accompanying drawings and embodiments. However, the exemplary embodiments can be implemented in many forms and should not be construed as limited to the embodiments set forth herein; rather, these embodiments are provided to make the application more comprehensive and complete, and to fully convey the concept of the exemplary embodiments to those skilled in the art. The same reference numerals in the figures denote the same or similar structures, and therefore repeated descriptions of them will be omitted. Terms describing position and direction described in this application are illustrative based on the accompanying drawings, but changes can be made as needed, and all such changes are included within the scope of protection of this application. The accompanying drawings of this application are for illustrating relative positional relationships only and do not represent actual scale.

[0019] Light field display technology is a display technology that uses ray tracing to reconstruct three-dimensional scenes in space. It primarily simulates the diffuse light distribution received by the human eye when observing a real three-dimensional scene, using specialized display and light-control devices to reconstruct the three-dimensional spatial light field information, thereby providing a realistic three-dimensional dynamic display effect.

[0020] Light field display technology based on microlens arrays can reconstruct the optical depth of images through computational control. This technology features a lightweight and thin device that requires no coherent light source, making it a promising area for development. Figure 1 This is a schematic diagram of the imaging principle of this technology under the naked-eye 3D display architecture. The light field display technology reconstructs a real image in space by controlling the direction of the light beam. Figure 2 This diagram illustrates the imaging principle of this technology in a near-eye 3D display architecture. Light field display technology reconstructs a virtual image in space by controlling the direction of the light beam. In both the naked-eye and near-eye 3D display frames, the distances between the display 100 and the microlens array 200, the focal length of the microlens array 200, and the distance between the imaging surface 300 and the microlens array 200 all satisfy the following Gaussian formula: ; Where u represents the distance between the display 100 and the microlens array 200; v represents the distance between the imaging surface 300 and the microlens array 200; and f represents the focal length of the microlens array 200.

[0021] In the reconstruction of 3D images, light field display technology based on microlens arrays has a central depth plane with optimal imaging quality. Figure 3 The curve showing the change in image quality with viewing depth is shown below. Figure 3 As shown, the resolution of the image decreases rapidly as the viewing depth deviates from the central depth plane, resulting in a limited effective display depth range, which restricts the visual experience and practicality of 3D display.

[0022] To enhance the visual experience of 3D display technology, current methods primarily employ microlens array structures with multiple central depth planes to extend the depth of field in light field display technology. The formation of multiple central depth planes is mainly achieved through differentiated design of specific parameters of the microlens array, such as polarization state and incident light wavelength. Figure 4 As shown, time-division multiplexing technology is used to control the timing of the microlens array, which can effectively fuse two high-resolution depth ranges to form two central depth planes, thereby expanding the overall depth of field.

[0023] In current multi-center depth plane technology, polarization multiplexing is a commonly used implementation method. Polarization multiplexing technology designs the polarization of a microlens array, allowing the microlens array to correspond to different focal lengths under different polarization states, thereby forming multiple central depth planes. High-definition imaging ranges at different depths are then rapidly switched and fused. However, this approach requires the introduction of additional polarization conversion and control components, increasing system complexity and manufacturing costs.

[0024] In view of this, embodiments of this application provide a three-dimensional display device that uses diffractive lenses to image the displayed image on the screen. Utilizing the wavelength sensitivity of diffraction transmission, diffractive lenses with different focal lengths can image light of different wavelengths onto the same position. By designing at least four diffractive lenses with different focal lengths in the diffractive microlens array, it is possible to image the displayed image onto different image planes, effectively expanding the depth of field of the three-dimensional display device. This eliminates the need for additional polarization conversion and control components, reducing the complexity of the device and lowering manufacturing costs.

[0025] Figure 5 This is one of the structural schematic diagrams of a three-dimensional display device provided in the embodiments of this application.

[0026] like Figure 5 As shown in the embodiment of this application, a three-dimensional display device includes a display screen 1 and a diffractive lens array 2. The display screen 1 is used for image display, and each frame of the image displayed on the display screen 1 is composed of at least two sub-image frames that are switched on and off. The diffractive lens array 2 is located on the light-emitting side of the display screen 1, and the diffractive lens array 2 includes at least four types of diffractive lenses 21 with different focal lengths. The diffractive lens array 2 is used to image each sub-image frame onto different image planes, and the different image planes are at different distances from the diffractive lens array 2.

[0027] A diffractive lens is a diffractive optical element whose focal length is inversely proportional to the wavelength of the incident light. According to Gauss's law, with the distance u from the diffractive lens array 2 to the display screen 1 remaining constant, the distance v from the imaging surface 3 to the diffractive lens array 2 changes with the focal length of the diffractive lens array 2. Therefore, the same type of diffractive lens 21 has the same imaging position for light of the same wavelength, while the imaging positions for light of different wavelengths are different. By independently designing the focal length of each diffractive lens, any three of the at least four diffractive lenses can image the three primary colors of light at the same position, forming a colorless image plane. Any other three of the at least four diffractive lenses can image the three primary colors of light at another position. Thus, by switching the imaging of the diffractive lenses in the diffractive lens array, at least two colorless image planes can be constructed, and the distances between the different image planes and the diffractive lens array 2 are different, thereby effectively expanding the depth of field of the three-dimensional display device. The three-dimensional display device provided in this application embodiment does not require the introduction of additional polarization conversion and control components, reducing the complexity of the device and lowering the manufacturing cost.

[0028] Specifically, such as Figure 5 As shown, any three of the at least four types of diffractive lenses 21 constitute an imaging group 211, and the at least four types of diffractive lenses can be matched to form at least two imaging groups. Each imaging group 211 is used to image a sub-image frame.

[0029] The emitted light from display screen 1 includes light in a first wavelength band, a second wavelength band, and a third wavelength band, each with a different color. Specifically, the first wavelength band can be red light with a wavelength range of 630nm to 650nm; the second wavelength band can be green light with a wavelength range of 515nm to 540nm; and the third wavelength band can be blue light with a wavelength range of 450nm to 480nm.

[0030] The image plane formed by one type of diffractive lens in each imaging group 211 imaging light in the first wavelength band coincides with the image plane formed by another type of diffractive lens imaging light in the second wavelength band, and the image plane formed by a third type of diffractive lens imaging light in the third wavelength band, thereby forming a colorless image plane. At least four types of diffractive lenses 21 can construct at least two colorless image planes, and at least two sub-image frames displayed on the screen can be imaged on different image planes, thereby effectively expanding the depth of field of the three-dimensional display device.

[0031] In some embodiments, such as Figure 6 As shown in (a), at least four types of diffractive lenses include a first lens 201, a second lens 202, a third lens 203, and a fourth lens 204. Each frame of the image displayed on the display screen 1 can be composed of a first sub-image frame and a second sub-image frame superimposed.

[0032] The first lens 201, the second lens 202, and the third lens 203 constitute the first imaging group 212. By designing the focal lengths of the first lens 201, the second lens 202, and the third lens 203 respectively, the first imaging group 212 can image the three different wavelengths of light emitted from the display screen 1 onto the first image plane 31. At this time, the image displayed on the display screen 1 is the first sub-image frame, and only the pixel unit corresponding to the first imaging group 212 emits light, while the pixel units in other areas do not emit light. Thus, the first imaging group 212 can image the first sub-image frame onto the first image plane 31.

[0033] like Figure 6 As shown in (b), the first lens 201, the second lens 202, and the fourth lens 204 can constitute the second imaging group 213, or, as shown in (b), Figure 6 As shown in (c), the second lens 202, the third lens 203, and the fourth lens 204 can constitute the second imaging group 213. By designing the focal length of the fourth lens 204, the second imaging group 213 can image the three different wavelengths of light emitted from the display screen 1 onto the second image plane 32. At this time, the image displayed on the display screen 1 is the second sub-image frame, and only the pixel unit corresponding to the second imaging group 213 emits light, while the pixel units in other areas do not emit light. Thus, the second imaging group 213 can image the second sub-image frame onto the second image plane 32.

[0034] The first sub-image frame and the second sub-image frame switched and displayed on the display screen 1 can be imaged on the first image plane 31 and the second image plane 32 respectively, and the distance between the different image planes and the diffraction lens array 2 is different, thereby effectively expanding the depth of field of the three-dimensional display device.

[0035] In some embodiments, such as Figure 7 As shown in (a), at least four types of diffractive lenses include a first lens 201, a second lens 202, a third lens 203, a fourth lens 204, and a fifth lens 205. Each frame of the image displayed on the display screen 1 is composed of a first sub-image frame, a second sub-image frame, and a third sub-image frame superimposed on each other.

[0036] The first lens 201, the second lens 202, and the third lens 203 constitute the first imaging group 212. By designing the focal lengths of the first lens 201, the second lens 202, and the third lens 203 respectively, the first imaging group 212 can image the three different wavelengths of light emitted from the display screen 1 onto the first image plane 31. At this time, the image displayed on the display screen 1 is the first sub-image frame, and only the pixel unit corresponding to the first imaging group 212 emits light, while the pixel units in other areas do not emit light. Thus, the first imaging group 212 can image the first sub-image frame onto the first image plane 31.

[0037] like Figure 7As shown in (b), the second lens 202, the third lens 203 and the fourth lens 204 constitute the second imaging group 213. By designing the focal length of the fourth lens 204, the second imaging group 213 can image the three different wavelengths of light emitted from the display screen 1 onto the second image plane 32. At this time, the image displayed on the display screen 1 is the second sub-image frame, and only the pixel unit corresponding to the second imaging group 213 emits light, while the pixel units in other areas do not emit light. Thus, the second imaging group 213 can image the second sub-image frame onto the second image plane 32.

[0038] like Figure 7 As shown in (c), the first lens 201, the second lens 202, and the fifth lens 205 constitute the third imaging group 214. By designing the focal length of the fifth lens 205, the third imaging group 214 can image the three different wavelengths of light emitted from the display screen 1 onto the third image plane 33. At this time, the image displayed on the display screen 1 is the third sub-image frame, and only the pixel units corresponding to the third imaging group 214 emit light, while the pixel units in other areas do not emit light. Thus, the third imaging group 214 can image the third sub-image frame onto the third image plane 33.

[0039] The first sub-image frame, the second sub-image frame, and the third sub-image frame displayed on the display screen 1 can be imaged on the first image plane 31, the second image plane 32, and the third image plane 33, respectively. The distances between the different image planes and the diffraction lens array 2 are different, thereby effectively expanding the depth of field of the three-dimensional display device.

[0040] The diffractive lens array includes four or five diffractive lenses with different focal lengths as an example. In specific embodiments, the diffractive lens array may also include more diffractive lenses with different focal lengths to construct more image planes, thereby further extending the depth of field of the 3D display device. However, the more types of diffractive lenses there are, the more times the display screen needs to switch between displayed sub-image frames, the higher the refresh rate requirement for the display screen, and the greater the pressure on the display screen driver. Therefore, in practical applications, the number and types of diffractive lenses must be selected based on the depth of field extension requirements and the display screen hardware performance.

[0041] In practice, different types of diffractive lenses can be arranged periodically. For example, a diffractive lens array comprising four types of diffractive lenses: a first lens, a second lens, a third lens, and a fourth lens, can be used as an example. Figure 8 As shown in (a), multiple first lenses 201, multiple second lenses 202, multiple third lenses 203 and multiple fourth lenses 204 are arranged in multiple rows. A row of first lenses 201, a row of second lenses 202, a row of third lenses 203 and a row of fourth lenses 204 are arranged in sequence to form a repeating unit 22. Multiple repeating units 22 are arranged periodically along the row or column direction of the diffraction lens array.

[0042] Figure 8 (b) shows the image display effect when the first sub-image frame is displayed on the screen. Figure 8 (c) indicates the image display effect when the display screen shows the second sub-image frame. Multiple repeating units 22 are arranged periodically along the row or column direction of the diffractive lens array, which can ensure that the beam coverage of each image plane is uniform and avoid local imaging distortion.

[0043] In some embodiments, such as Figure 9 As shown, the display screen 1 includes multiple pixel units 111, and a diffraction lens 21 is provided corresponding to at least one pixel unit 111. In order to image different sub-image frames onto different image planes, each pixel unit 111 corresponding to the same diffraction lens 21 needs to emit light of different wavelengths when displaying different sub-image frames, while each pixel unit 111 corresponding to the same diffraction lens 21 needs to emit light of the same wavelength when displaying the same sub-image frame, so as to avoid color difference.

[0044] In some embodiments, such as Figure 9 As shown, display screen 1 is a field color sequence display screen, which includes a backlight module 12 and a display panel 11.

[0045] The backlight module 12 is used to provide backlight, and the backlight module 12 includes three light sources 122, each of which is arranged in an array. The three light sources 122 are used to emit light in the first band, the second band, and the third band, respectively.

[0046] The display panel 11 is located on the light-emitting side of the backlight module 12, and includes multiple pixel units 111. The field-sequential display activates the entire light-emitting area of ​​each pixel unit 111, with no sub-pixel division among the pixel units 111, thus improving light energy utilization compared to traditional spatial color mixing displays. The field-sequential display achieves a 100% pixel fill ratio, eliminating the screen-door effect caused by black gaps in near-eye displays and enhancing visual immersion. Furthermore, by independently designing the focal length of each diffractive lens 21, any three diffractive lenses 21 can image light of three different wavelengths at the same position, forming a color-aberration-free image plane. Each pixel unit corresponding to each diffractive lens 21 emits light of the same wavelength at the same time, avoiding the wavelength sensitivity of diffractive optical elements and achieving color-aberration-free imaging.

[0047] For example, in a naked-eye 3D display frame, display screen 1 is selected as a field color sequence display screen with a frequency of 120Hz, and the pixel unit 111 has a spacing of 12μm. The diffraction lens 21 includes a first lens 201, a second lens 202, a third lens 203, and a fourth lens 204. A row of first lenses 201, a row of second lenses 202, a row of third lenses 203, and a row of fourth lenses 204 are arranged sequentially to form a repeating unit 22, the size of which is 48μm × 48μm. The distance from the diffraction lens array 2 to the display screen 1 is 2mm. During the 0~8.3ms time period, the first lens 201, the second lens 202, and the third lens 203 image the three different wavelengths of light emitted from the display screen 1 onto a first image plane 31, the distance from which the first image plane 31 is located is 300mm. During the 8.3~16.6ms period, the first lens 201, the second lens 202 and the fourth lens 204 image the three different wavelengths of light emitted from the display screen 1 onto the second image plane 32, and the distance from the second image plane 32 to the diffraction lens array 2 is 450mm.

[0048] The first and second sub-image frames displayed on the screen can be imaged on the first image plane 31 and the second image plane 32, respectively. The distances between the different image planes and the diffraction lens array 2 are different, effectively extending the depth of field of the 3D display device to ±15%. Compared to traditional displays, using a field-sequence display increases the brightness of the 3D display device by 200% and eliminates the screen-door effect. The aforementioned 3D display device can also be applied to near-eye 3D display architectures, with different parameters set according to the needs of different display devices.

[0049] In some embodiments, the diffractive lens needs to be an optical element that works based on the principle of light diffraction. Specifically, the diffractive lens can be a Fresnel zone plate, a surface relief diffractive lens, a holographic optical lens, or a superlens, etc.

[0050] Fresnel zone plates are constructed by creating a series of concentric rings of alternating light and dark on a planar substrate, allowing only odd or even half-wave zones to transmit light. The optical path difference between adjacent transmitted light zones at the focal point is half a wavelength, ensuring that the light waves are in phase when they reach the focal point. Constructive interference is achieved through diffraction, ultimately resulting in efficient focusing.

[0051] Surface-embossed diffraction lenses fold the continuous curved surface of a traditional lens into a two-dimensional planar structure by etching a series of concentric ring-shaped micrometer-level steps on a flat substrate. When light waves pass through the steps at different heights, a precise phase delay is generated, thereby achieving constructive interference at the focal point and completing focusing.

[0052] Holographic optical elements use laser interference technology to record the interference fringe pattern formed by a converging light wave and a reference beam onto a photosensitive material, essentially creating a complex diffraction grating. When light shines on the holographic optical element, it diffracts the light and reconstructs the original converging light wave, thus acting as a lens.

[0053] A superlens integrates a large number of nanostructures much smaller than the wavelength of light on a single plane. Each nanostructure can be considered an independent optical phase modulator. By precisely designing and arranging the nanoantennas geometrically, point-to-point arbitrary reshaping of the incident light wavefront can be achieved, thus achieving more efficient and precise focusing than traditional diffraction elements. Optical elements that operate based on the principle of light diffraction have a strong and predictable dependence on the focal length of light.

[0054] By independently designing the focal length of each diffraction lens, the three diffraction lenses can image the light of the three primary colors onto the same position, forming a colorless image plane. By setting at least four diffraction lenses with different focal lengths in the diffraction lens array, at least two colorless image planes can be constructed, thereby effectively expanding the depth of field of the 3D display device.

[0055] Based on the same inventive concept, embodiments of this application also provide a display driving method, such as... Figure 10 As shown, the display driving method provided in this application embodiment may include the following steps: S1001, Receive image data; S1002. Control the display screen to switch at least two sub-image frames for superimposed display when displaying each frame of image, based on the image data.

[0056] In this embodiment, different sub-image frames display the same content, but are imaged onto different image planes by a diffractive lens array. The distances between these image planes and the diffractive lens array are different. A diffractive lens is a diffractive optical element whose focal length is inversely proportional to the wavelength of the incident light. According to Gauss's law, with a fixed distance between the diffractive lens array and the display screen, the distance from the imaging plane to the diffractive lens array changes with the focal length of the array. Therefore, the same type of diffractive lens has the same imaging position for light of the same wavelength, but different imaging positions for light of different wavelengths. By independently designing the focal length of each diffractive lens, any three of at least four types of diffractive lenses can image the three primary colors of light onto the same position, forming a color-aberration-free image plane. Any three of the four diffractive lenses can image the three primary colors of light at another position. Thus, by switching the diffractive lenses in the diffractive lens array, at least two achromatic image planes can be constructed, and the distances between the different image planes and the diffractive lens array are different, thereby effectively expanding the depth of field of the three-dimensional display device.

[0057] In some embodiments, such as Figure 6 As shown, the diffraction lens array 2 in the 3D display device includes: a first lens 201, a second lens 202, a third lens 203, and a fourth lens 204. Figure 6 As shown in (a), the first lens 201, the second lens 202, and the third lens 203 constitute the first imaging group 212. By designing the focal lengths of the first lens 201, the second lens 202, and the third lens 203 respectively, the first imaging group 212 can image three different wavelengths of light emitted from the display screen 1 at the same position, forming a first image plane 31. Figure 6 As shown in (b), the first lens 201, the second lens 202, and the fourth lens 201 constitute the second imaging group 213, or, as shown in (b). Figure 6 As shown in (c), the second lens 202, the third lens 203, and the fourth lens 204 constitute the second imaging group 213. By designing the focal length of the fourth lens 204, the second imaging group 213 can image the light emitted from the display screen 1 in three different wavelengths onto the same position, forming the second image plane 32. Each frame of the image displayed on the display screen 1 is composed of the superposition of the first sub-image frame and the second sub-image frame. The first sub-image frame and the second sub-image frame displayed on the display screen 1 can be imaged onto the first image plane 31 and the second image plane 32, respectively, and the distances between the different image planes and the diffraction lens array 2 are different, thereby effectively expanding the depth of field of the three-dimensional display device.

[0058] In specific implementation, such as Figure 11 As shown, in step S1002, the display screen is controlled to switch at least two sub-image frames for superimposed display when displaying each frame of image, specifically including: S1101. In the first time period, each pixel unit corresponding to the first imaging group is controlled to display the first sub-image frame, and the first imaging group images the first sub-image frame onto the first image plane. S1102, In the second time period, control each pixel unit corresponding to the second imaging group to display the second sub-image frame, and the second imaging group images the second sub-image frame onto the second image plane.

[0059] In this embodiment, by independently designing the focal length of each diffraction lens, the three diffraction lenses respectively image the light of the three primary colors at the same position, forming an image plane without chromatic aberration. The diffraction lens array includes at least four diffraction lenses with different focal lengths, capable of constructing at least two image planes without chromatic aberration, with different distances between the different image planes and the diffraction lens array. The first sub-image frame and the second sub-image frame are imaged onto the first image plane and the second image plane, respectively, thereby effectively expanding the depth of field of the three-dimensional display device.

[0060] In some embodiments, each pixel unit corresponding to the same diffractive lens emits light of the same wavelength within the same time period. There is no sub-pixel segmentation among the pixel units, which improves the light energy utilization of the display device compared to traditional spatial color mixing display methods. Furthermore, the fill ratio of each pixel unit reaches 100%, eliminating the screen-door effect caused by black gaps in near-eye displays, thereby enhancing visual immersion. In other embodiments, each pixel unit corresponding to the same diffractive lens emits light of different wavelengths within different time periods. Since the imaging position of the sub-image frame differs within different time periods, and the focal length of the diffractive lens is inversely proportional to the wavelength of the incident light, each pixel unit corresponding to the same diffractive lens needs to emit light of different wavelengths when displaying different sub-image frames to ensure that different wavelengths of light are imaged at different positions, thus imaging different sub-image frames.

[0061] In some embodiments, the first time period can be divided into a first sub-time period, a second sub-time period, and a third sub-time period. The first sub-time period controls each pixel unit corresponding to the first lens 201 to emit light of the first wavelength band, while other pixel units do not emit light. The second sub-time period controls each pixel unit corresponding to the second lens 202 to emit light of the second wavelength band, while other pixel units do not emit light. The third sub-time period controls each pixel unit corresponding to the third lens 203 to emit light of the third wavelength band, while other pixel units do not emit light.

[0062] The second time period can be divided into a fourth sub-time period, a fifth sub-time period, and a sixth sub-time period. The fourth sub-time period controls each pixel unit corresponding to the fourth lens 204 to emit light of the first wavelength band, while other pixel units do not emit light. The fifth sub-time period controls each pixel unit corresponding to the first lens 201 to emit light of the second wavelength band, while other pixel units do not emit light. The sixth sub-time period controls the pixel unit corresponding to the second lens 202 to emit light of the third wavelength band, while other pixel units do not emit light.

[0063] The first and second time periods are each further divided into three sub-time periods. Each pixel unit independently emits light in three different wavelengths, thus splitting the first and second sub-image frames into three monochrome images that are displayed alternately. The three monochrome images in the first time period are imaged on the first image plane, and the three monochrome images in the second time period are imaged on the second image plane. The positions of the first and second image planes are different. The first and second sub-image frames are switched and superimposed for display, thereby effectively expanding the depth of field of the 3D display device.

[0064] In some embodiments, step S1002, which controls the display screen to switch at least two sub-image frames for superimposed display when displaying each frame of image based on image data, further includes: During a first time period, controlling the three light sources in the backlight module to emit light of a first wavelength and light of a second wavelength, performing data fusion on each pixel unit corresponding to the first lens 201, and preventing other pixel units from emitting light, thereby imaging the first wavelength light onto the first image plane and the second wavelength light onto the second image plane. During a second time period, controlling the three light sources in the backlight module to emit light of a second wavelength and light of a third wavelength, performing data fusion on each pixel unit corresponding to the second lens 202, and preventing other pixel units from emitting light, thereby imaging the second wavelength light onto the first image plane. The third wavelength light is imaged onto the second image plane. During a third time period, controlling the three light sources in the backlight module to emit light of a third wavelength, controlling each pixel unit corresponding to the third lens 203 to emit light of the third wavelength, and imaged onto the first image plane. During the fourth time period, the three light sources in the backlight module are controlled to emit light in the first wavelength band, and the pixel units corresponding to the fourth lens 204 are controlled to emit light in the first wavelength band and image it onto the second image plane. By controlling the light emitted by the backlight module and the pixel units corresponding to the diffraction lens, the first sub-image frame is imaged onto the first image plane, and the second sub-image frame is imaged onto the second image plane. The distances between the different image planes and the diffraction lens array are different. The first sub-image frame and the second sub-image frame are switched and superimposed for display, thereby effectively expanding the depth of field of the three-dimensional display device.

[0065] The three-dimensional display device provided in this application includes a display screen and a diffractive lens array. Each frame of image displayed on the display screen is composed of at least two sub-image frames that are switched and superimposed. The diffractive lens array is located on the light-emitting side of the display screen and includes at least four types of diffractive lenses with different focal lengths. A diffractive lens is a diffractive optical element whose focal length is inversely proportional to the wavelength of the incident light. By independently designing the focal length of each diffractive lens, any three of the at least four diffractive lenses can image the three primary colors of light onto the same position, forming a colorless image plane. Any other three of the at least four diffractive lenses can image the three primary colors of light onto another position. Thus, by switching the imaging of the diffractive lenses in the diffractive lens array, at least two colorless image planes can be constructed, and the distances between the different image planes and the diffractive lens array are different, thereby effectively expanding the depth of field of the three-dimensional display device. The three-dimensional display device provided in this application does not require the introduction of additional polarization conversion and control components, reducing the complexity of the device and lowering the manufacturing cost.

[0066] Although preferred embodiments of this application have been described, those skilled in the art, upon learning the basic inventive concept, can make other changes and modifications to these embodiments. Therefore, the appended claims are intended to be interpreted as including the preferred embodiments as well as all changes and modifications falling within the scope of this application.

[0067] Obviously, those skilled in the art can make various modifications and variations to this application without departing from the spirit and scope of this application. Therefore, if such modifications and variations fall within the scope of the claims of this application and their equivalents, this application also intends to include such modifications and variations.

Claims

1. A three-dimensional display device, characterized in that, include: A display screen for displaying images; each frame of the image displayed on the display screen is composed of at least two sub-image frames that are switched on and overlaid. and A diffractive lens array is located on the light-emitting side of the display screen; the diffractive lens array includes at least four types of diffractive lenses with different focal lengths; the diffractive lens array is used to image each of the sub-image frames onto different image planes, and the different image planes are at different distances from the diffractive lens array.

2. The three-dimensional display device as described in claim 1, characterized in that, Any three of the at least four diffraction lenses constitute an imaging group, which is used to image any one sub-image frame. The light emitted from the display screen includes a first wavelength, a second wavelength, and a third wavelength; the first wavelength, the second wavelength, and the third wavelength are different colors. The image plane of one type of diffractive lens in the imaging group that images the light of the first wavelength band coincides with the image plane of another type of diffractive lens that images the light of the second wavelength band, and the image plane of the third type of diffractive lens that images the light of the third wavelength band.

3. The three-dimensional display device as described in claim 2, characterized in that, The at least four types of diffractive lenses include a first lens, a second lens, a third lens, and a fourth lens; Each frame of the image displayed on the screen is composed of a first sub-image frame and a second sub-image frame superimposed on each other; The first lens, the second lens, and the third lens constitute a first imaging group; the first lens, the second lens, and the fourth lens constitute a second imaging group, or the second lens, the third lens, and the fourth lens constitute a second imaging group. The first imaging group is used to image the first sub-image frame onto a first image plane, and the second imaging group is used to image the second sub-image frame onto a second image plane.

4. The three-dimensional display device as described in claim 3, characterized in that, Multiple first lenses, multiple second lenses, multiple third lenses, and multiple fourth lenses are arranged in multiple rows. A row of first lenses, a row of second lenses, a row of third lenses, and a row of fourth lenses are arranged sequentially to form a repeating unit. Multiple repeating units are arranged periodically along the row or column direction of the diffraction lens array.

5. The three-dimensional display device as described in claim 4, characterized in that, The display screen includes multiple pixel units, and one diffraction lens is provided corresponding to at least one pixel unit; Each pixel unit corresponding to the same diffraction lens emits light of different wavelengths when displaying different sub-image frames; each pixel unit corresponding to the same diffraction lens emits light of the same wavelength when displaying the same sub-pixel frame.

6. The three-dimensional display device as described in claim 5, characterized in that, The display screen is a field color sequence display screen, which includes: A backlight module for providing backlight; the backlight module includes three light sources, each arranged in an array; the three light sources are respectively used to emit light in the first wavelength band, the second wavelength band, and the third wavelength band; and The display panel is located on the light-emitting side of the backlight module; the display panel includes multiple pixel units.

7. The three-dimensional display device as described in any one of claims 1 to 6, characterized in that, The diffraction lens is a Fresnel zone plate, a surface relief diffraction lens, a holographic optical lens, or a superlens.

8. A display driving method for a three-dimensional display device as described in any one of claims 1 to 7, characterized in that, include: Receive image data; Based on the image data, the display screen is controlled to switch at least two sub-image frames for superimposed display when displaying each frame of image; In this system, different sub-image frames display the same content, and the different sub-image frames are imaged on different image planes by the diffractive lens array. The distance between the different image planes and the diffractive lens array is different.

9. The display driving method as described in claim 8, characterized in that, The diffraction lens array in the three-dimensional display device includes: a first lens, a second lens, a third lens, and a fourth lens; the first lens, the second lens, and the third lens constitute a first imaging group; the first lens, the second lens, and the fourth lens constitute a second imaging group, or the second lens, the third lens, and the fourth lens constitute a second imaging group; each frame of image displayed on the display screen is composed of a first sub-image frame and a second sub-image frame superimposed. The step of controlling the display screen to switch at least two sub-image frames for superimposed display when displaying each frame of image based on the image data specifically includes: During the first time period, each pixel unit corresponding to the first imaging group is controlled to display the first sub-image frame, and the first imaging group images the first sub-image frame onto the first image plane. During the second time period, each pixel unit corresponding to the second imaging group is controlled to display the second sub-image frame, and the second imaging group images the second sub-image frame onto the second image plane.

10. The display driving method as described in claim 9, characterized in that, Within the same time period, each pixel unit corresponding to the same type of diffraction lens emits light of the same wavelength. At different times, the pixel units corresponding to the same diffraction lens emit light of different wavelengths.

Images