Three-dimensional display device

Abstract

The present invention relates to display technologies, and particularly to a device for realizing naked-eye 3D display. The 3D display device according to one aspect of the present invention includes: a backlight panel configured to convert a light beam emitted by a light source into a first collimated light beam; a spatial light modulator located in the propagation direction of the first collimated light beam, configured to load multi-view mixed image information onto the first collimated light beam by amplitude modulation to form a second collimated light beam; and a positive lens group located in the propagation direction of the second collimated light beam, configured to project images of different views in the image carried by the second collimated light beam to their respective corresponding viewing positions.

Description

Technical Field

[0001] The present invention relates to display technologies, and particularly to a device for realizing naked-eye three-dimensional display. Background Art

[0002] There is a displacement of 5-6 cm between the left and right eyes of humans in the horizontal direction. Therefore, there is a certain distance between the corresponding points on the actual object in the images seen by the left and right eyes. Through this difference, the distance and depth of an object can be judged. Three-dimensional (3D) display technology is a technology that uses a series of optical methods to cause parallax between the left and right eyes of a person, thereby forming a stereoscopic effect in the brain. Current 3D display technologies include two major types: glasses-type display and naked-eye display. Due to the need not to wear special glasses, naked-eye 3D display is more favored by the market.

[0003] However, existing naked-eye 3D display technologies have many disadvantages. For example, the hardware devices for implementation are large in size and difficult to be integrated into small devices such as mobile phones. In addition, for naked-eye 3D displays based on lenticular lenses and barrier methods, it is difficult to eliminate stray light, which easily causes serious visual fatigue. Summary of the Invention

[0004] An object of the present invention is to provide a device for realizing naked-eye three-dimensional display, which has the advantages of low manufacturing cost, simple design, and compact structure.

[0005] The three-dimensional display device according to one aspect of the present invention includes:

[0006] A backlight panel configured to convert a light beam emitted by a light source into a first collimated light beam;

[0007] A spatial light modulator located in the propagation direction of the first collimated light beam, configured to load multi-view mixed image information onto the first collimated light beam by amplitude modulation to form a second collimated light beam; and

[0008] A positive lens group located in the propagation direction of the second collimated light beam, configured to project images of different views in the image carried by the second collimated light beam to their respective corresponding viewing positions.

[0009] Preferably, in the above device, the positive lens group is a Fresnel lens group.

[0010] Preferably, in the above device, the backlight panel includes:

[0011] A light guide plate including a first microstructure located on the upper surface, lower surface or inside of the light guide plate, the first microstructure having periodically distributed first units, and the light beam emitted by the light source being scattered to the outside of the light guide plate through the first microstructure; and

[0012] An optical film stacked with the light guide plate, which includes a second microstructure on the surface of the optical film, the second microstructure has periodically distributed second units, and the light beam scattered to the outside of the light guide plate by the first microstructure is transformed into the first collimated light beam by the second microstructure.

[0013] Preferably, in the above device, the first unit is one of a micro prism, a micro lens, a free-form surface lens, or a pit.

[0014] Preferably, in the above device, the second unit is one of a micro lens, a Fresnel lens, or a thin film lens.

[0015] Preferably, in the above device, the backlight plate further includes a light shielding plate, which includes a light shielding structure that matches and corresponds to the first microstructure and the second microstructure to filter out stray light emitted from the second microstructure.

[0016] Preferably, in the above device, the light shielding plate is disposed at one of the following positions: between the light guide plate and the optical film, inside the light guide plate, and inside the optical film.

[0017] Preferably, in the above device, the light source is integrated in the device and is located at the side of the backlight plate.

[0018] Preferably, in the above device, the light source is an LED line array light source.

[0019] Preferably, in the above device, the spatial light modulator is a liquid crystal display unit.

[0020] Preferably, in the above device, the spatial light modulator includes a plurality of volume pixels, each volume pixel includes a plurality of sub-pixels, each sub-pixel corresponds to a different viewing angle, the Fresnel lens group includes a plurality of Fresnel lenses, and each Fresnel lens is configured to project the light beams from the sub-pixels corresponding to the same viewing angle among the plurality of volume pixels to the same viewing position.

[0021] Preferably, in the above device, each Fresnel lens is divided into a plurality of regions, and each region is configured to project the light beams from the sub-pixels corresponding to the same viewing angle among the plurality of volume pixels to the same viewing position.

[0022] Preferably, in the above device, it further includes a light shielding plate located between the spatial light modulator and the Fresnel lens group.

[0023] Preferably, in the above device, the light source is a white light source or a three-primary color light source, and the device further includes a color filter stacked with the spatial light modulator and the Fresnel lens group.

[0024] Preferably, in the above device, the color filter is disposed between the spatial light modulator and the Fresnel lens group. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 FIG. is a schematic block diagram of a three-dimensional display device according to an embodiment of the present invention.

[0026] Figure 2 For another embodiment of the present invention, it can be applied to Figure 1 FIG. is a schematic diagram of a backlight panel of the device shown.

[0027] Figure 3 For Figure 1 FIG. is a schematic diagram of a Fresnel lens of the device shown.

[0028] Figure 4 FIG. is a schematic diagram of the converging action of the Fresnel lens.

[0029] Figure 5 FIG. is a schematic diagram of implementing a single-viewpoint structure using a combination of a backlight panel, a spatial light modulator, and a Fresnel lens according to an embodiment of the present invention.

[0030] Figure 6a and 6b FIG. is a schematic diagram of pixelating the Fresnel lens according to an embodiment of the present invention.

[0031] Figure 7 FIG. is a schematic diagram of controlling the perspective of a volumetric pixel of a single pixelated Fresnel lens according to an embodiment of the present invention.

[0032] Figure 8 FIG. is a schematic diagram of controlling the perspective of a volumetric pixel of multiple pixelated Fresnel lenses according to an embodiment of the present invention. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0033] Hereinafter, the objectives of the present invention will be described in detail with reference to the accompanying drawings.

[0034] Figure 1 FIG. is a schematic block diagram of a device for realizing naked-eye three-dimensional display according to an embodiment of the present invention.

[0035] Figure 1 The device shown includes a backlight panel 110, a spatial light modulator 120, and a positive lens group 130. The backlight panel 110 may be, for example, a directional backlight panel, and the positive lens group 130 may be, for example, a Fresnel lens group (exemplarily, the Fresnel lens group is taken as an example in the following description). Optionally but not necessarily, the light source 140 may be used as Figure 1 a component unit of the device shown. Preferably, the light source 140 may be an LED line array light source.

[0036] SeeFigure 1 The light beam emitted by the light source 140 is converted into a collimated light beam B1 (hereinafter also referred to as the first collimated light beam B1) in one or more directions by the backlight panel 110. The spatial light modulator 120 is disposed in the propagation direction of the first collimated light beam B1, and loads multi-view mixed image information onto the first collimated light beam B1 by amplitude modulation to form a collimated light beam B2 (hereinafter also referred to as the second collimated light beam B2). The Fresnel lens group 130 is disposed in the propagation direction of the second collimated light beam B2, and projects images of different views in the image carried by the second collimated light beam B2 to their respective corresponding viewing positions through the phase modulation of the pixelated Fresnel lens, so that different images can be observed at different positions, thereby achieving the effect of naked-eye 3D display.

[0037] It should be noted that in this specification, a collimated light beam, a parallel light, a directional light beam, and a converging light beam propagating in one direction refer to outgoing light rays with a half-height width of the divergence angle within 30°. Preferably, the half-height width of the divergence angle of the outgoing light rays is within 10°.

[0038] Figure 2 For the backlight panel applicable to the device shown in accordance with another embodiment of the present invention Figure 1 Schematic diagram of the backlight panel.

[0039] Figure 2 The backlight panel 110 shown includes a light guide plate 111 and an optical film 112. The optical film 112 can be, for example, a micro-nano optical film. In the following description, the micro-nano optical film is exemplarily taken as a specific example of the optical film 112. As Figure 2 shown, a first microstructure 111A having periodically distributed first units (shown as pits in the figure) is formed on the upper surface of the light guide plate 111. The light source 140 is located at the side of the light guide plate 111. After the light beam emitted by it enters the light guide plate 111, it is scattered to the outside of the light guide plate 111 by the first microstructure 111A.

[0040] Although Figure 2 the first microstructure 111A shown in is formed on the upper surface of the light guide plate 111, it is also formed on the lower surface or inside of the light guide plate 111. Preferably, the size of the first microstructure is between 100 nm and 1 mm. In Figure 2 the backlight panel 110 shown, the first unit is exemplarily shown in the form of a pit, but it can also be other forms of optical elements, such as including but not limited to micro prisms, micro lenses, free-form surface lenses, etc.

[0041] Continue to refer to Figure 2, the optical film 112 is located below the light guide plate 111. The optical film 112 can be stacked with the light guide plate 111 or maintain a certain air gap with the light guide plate 111 (when the refractive index of the optical film is close to or higher than that of the light guide plate). In addition, a low refractive index layer can be inserted between the light guide plate 111 and the optical film 112 to avoid the formation of total reflection conditions in the light guide plate. As Figure 2 shown, a second microstructure 112A with a periodically distributed second unit is formed on the surface of the optical film 112. The second microstructure 112A is structurally matched with the first microstructure 111A, and its function is to transform the divergent light beam from the light guide plate 111 into a first collimated light beam B1 emitted along one or more directions. Preferably, the second micro-nano structure 112A adopts configurations such as a microlens array, a Fresnel lens array, a thin film lens array, a binary structure light array, etc. The lens units of the microlens array, the Fresnel lens array or the thin film lens array can be optimized according to the relative position with the microstructure in the light guide plate to obtain better collimation or convergence effects. For example, the diameter of each unit or microlens in the optical film 112 can be designed to be larger than the size of the unit or pit structure in the light guide plate 111.

[0042] In this embodiment, plastic or glass can be selected as the material of the light guide plate or the microlens, and its refractive index is between 1 and 2.5. Preferably, plastic can be used to make the product lighter and reduce costs. In addition, the light guide plate 111 can be composed of one material or composed of multiple materials with different refractive indices. The light guide plate and the optical film can be fabricated, for example, by using a gray-scale lithography process, a laser etching process, etc., and mass replication can be achieved by using a nanoimprint process.

[0043] Fresnel lenses can be divided into equal-height Fresnel lenses, equal-spacing Fresnel lenses, etc. Figure 3 For being applicable to Figure 1 the schematic diagram of the Fresnel lens of the device shown. As Figure 3 shown, a Fresnel lens can be regarded as an optical element formed by "collapsing" a continuous surface part of a traditional lens onto a plane. From the cross-section, its surface consists of a series of serrated grooves, and the central part is an elliptical arc. Each groove has a different angle with the adjacent groove, but all concentrate the light at one place to form a central focus, that is, the focus of the lens. Each groove can be regarded as an independent small lens that adjusts the light into parallel light or convergent light, as Figure 4 shown.

[0044] Figure 5 The schematic diagram shows a single-viewpoint structure realized by using a combination of a backlight panel, a spatial light modulator, and a Fresnel lens according to an embodiment of the present invention.

[0045] As Figure 5As shown, after the light beam emitted by the light source 140 is converted into a collimated beam B1 in one or more directions by the backlight panel 110, it is amplitude - modulated by the spatial light modulator 120, and after loading the perspective image information, a collimated beam B2 is formed. The Fresnel lens group 130 (exemplarily, Figure 5 taking one Fresnel lens as an example) converges the incident collimated beam B2 to a certain viewing angle. It should be noted that parallel light rays passing through any part of the Fresnel lens will converge to the same viewing angle. Without loss of generality, by changing the relative positions of the Fresnel lens, the backlight panel, and the spatial light modulator, the light rays in the figure can all be converged to the viewpoint 2. Further, by designing the focal length and the position of the optical axis center of the Fresnel lens, the light rays emitted from the spatial light modulator can be converged to any point or area behind the screen.

[0046] The spatial light modulator 120 is used for amplitude modulation, that is, loading image information of multi - perspective mixing. The spatial light modulator may include, for example, a display panel, a driving circuit, a control system, and software control, etc. According to the needs of specific application fields, the spatial light modulator can achieve monochromatic or color display. Preferably, the spatial light modulator 120 can be a liquid crystal display unit.

[0047] In this embodiment, the spatial light modulator 120 may include multiple volume pixels or amplitude - modulation pixels. Each volume pixel includes multiple sub - pixels, and each sub - pixel corresponds to a different viewing angle. Correspondingly, each Fresnel lens in the Fresnel lens group 130 is configured to project the light beams from the sub - pixels corresponding to the same viewing angle in multiple volume pixels to the same viewing position. For this purpose, each Fresnel lens is divided into multiple regions, and each region is configured to project the light beams from the sub - pixels corresponding to the same viewing angle in multiple volume pixels to the same viewing position. Further description will be made below.

[0048] Figure 6a and 6b is a schematic diagram of pixelizing the Fresnel lens according to an embodiment of the present invention. Among them, Figure 6a shows an exemplary example of dividing the Fresnel lens into regions, Figure 6b is an example of a pixelized Fresnel lens. Four Fresnel lenses are exemplarily shown in the figure. For each Fresnel lens, it is divided into 4 pixel units or regions of the same size, as Figure 6a shown. Each pixel unit is represented by a two - character code. The first digit is one of the numbers 1 - 4, which is used to identify the Fresnel lens or the viewing position, and the second digit is one of the letters a - d, which is used to identify the volume pixel of the spatial light modulator. In this embodiment, according to Figure 6bThe pixel units on each Fresnel lens are combined in the manner shown to obtain a pixelated Fresnel lens. That is, the pixel units 1a, 2a, 3a, and 4a on the first to fourth Fresnel lenses are incorporated into one combination (hereinafter, this logical combination is also referred to as the volume pixel of the pixelated Fresnel lens), the pixel units 1b, 2b, 3b, and 4b are incorporated into another combination, and so on for the remaining pixel units. There is a one-to-one correspondence between the volume pixels of the pixelated Fresnel lens and the volume pixels or amplitude modulation pixels of the spatial light modulator 120. In practical applications, according to the application field, the size of the screen pixels, and the characteristics of the Fresnel lens, multiple Fresnel lenses can be split and combined, or a single Fresnel lens can also be split into multiple pixel units.

[0049] Figure 7 FIG. is a schematic diagram of controlling the viewing angle by the volume pixel of a single pixelated Fresnel lens according to an embodiment of the present invention. Refer to Figure 7 , each volume pixel of the spatial light modulator is composed of 4 sub-pixels. Correspondingly, each volume pixel of the pixelated Fresnel lens is also composed of 4 pixel units (such as Figure 6b 1a, 1b, 1c, and 1d shown). There is a corresponding relationship between the pixel units of the pixelated Fresnel lens and the sub-pixels of the spatial light modulator. When a parallel light beam is incident on a volume pixel of the spatial light modulator, the 4 viewing angle mixed image information of the spatial light modulator is loaded in. Subsequently, the 4 pixel units of the pixelated Fresnel lens image the images of their respective corresponding viewing angles at 4 different observation regions or positions labeled with numbers 1, 2, 3, and 4, so that different images will be observed in different observation regions, thereby achieving the effect of naked-eye 3D display.

[0050] Figure 8 FIG. is a schematic diagram of controlling the viewing angle by the volume pixels of multiple pixelated Fresnel lenses according to an embodiment of the present invention. Without loss of generality, Figure 8 the embodiment shown still takes a display device with 4 viewing angles as an example for illustration. Refer to Figure 8 , for each volume pixel of the pixelated Fresnel lens, it is composed of 4 pixel units, and each pixel unit images the image of the corresponding viewing angle to the corresponding observation position. For example, in Figure 8Among them, the volume pixels of the leftmost pixelated Fresnel lens include pixel units 1a, 2a, 3a, and 4a, which respectively image the images of four different viewing angles of the volume pixels of the corresponding spatial light modulator to the corresponding viewing positions 1-4. The volume pixels of the second leftmost pixelated Fresnel lens include pixel units 1b, 2b, 3b, and 4b, which also respectively image the images of four different viewing angles of the volume pixels of the corresponding spatial light modulator to the corresponding viewing positions 1-4. On the other hand, for the pixel units at the same position of the volume pixels of each pixelated Fresnel lens, they correspond to the same viewing area. Thus, the observer can observe different images in different viewing areas, thereby achieving the effect of naked-eye 3D display.

[0051] In this embodiment, after the collimated beam B2 passes through the pixelated Fresnel lens, each perspective image generates multiple converging light fields in the viewing area space, and the converging light fields do not overlap with each other. Even after propagating a certain distance, the perspective images do not interfere with each other.

[0052] In the embodiment described above, preferably, a light shielding plate can be provided inside the backlight plate 110 or between the spatial light modulator 120 and the Fresnel lens group 130 to filter out unwanted stray light. For example, in Figure 2 the backlight plate shown, it can be considered to provide a light shielding plate between the light guide plate and the optical film or inside the light guide plate. The light shielding plate includes a light shielding plate that matches and corresponds to the first microstructure 111A and the second microstructure 112A, so as to filter out the stray light emitted from the second microstructure. The light shielding plate can be a single-layer or multi-layer independent structure, and can be integrated with any one or more of the light guide plate, the optical film, the spatial light modulator, and the Fresnel lens group to form a functional composite optical device.

[0053] It should be noted that the embodiment described above can also be applied to color display applications. For this purpose, a three-color (or white) LED light bar can be used as the light source, and a color filter is provided in the device for realizing naked-eye three-dimensional display. The color filter can be stacked with the Fresnel lens group and the spatial light modulator, and the stacking order can be changed. For example, the color filter can be provided between the backlight plate and the spatial light modulator, between the spatial light modulator and the Fresnel lens group, or behind the Fresnel lens group. Preferably, the color filter is provided between the spatial light modulator and the Fresnel lens group. The light beam emitted from the backlight plate provides the image information for multi-perspective naked-eye 3D display by the spatial light modulator. Subsequently, the wavelength information is loaded by the color filter, and finally the phase modulation is realized by the Fresnel lens group, so as to form multiple converging light fields in the visible area in front of the Fresnel lens group to achieve the effect of naked-eye 3D display.

[0054] Compared with the prior art, the device for realizing naked-eye 3D display of the present invention has many advantages. For example, the backlight panel (including LED light source, light guide plate and optical film) and the Fresnel lens can both be industrially produced by using the existing nanoimprinting technology, with mature manufacturing processes, easy guarantee of product consistency and cost reduction. Also, each unit of the backlight panel can be modularly designed, and each module realizes relatively independent optical characteristics (such as illumination uniformity, divergence angle of outgoing light, etc.), which decouples the parameters, simplifies the design process and makes the adjustment of optical parameters easier. Moreover, the device for realizing naked-eye 3D display of the present invention is composed of multiple stacked thin-film optical devices, which has good compatibility with the existing liquid crystal screen structure and broad application fields.

[0055] The principles and preferred embodiments of the present invention have been described above. However, the present invention should not be construed as limited to the specific embodiments discussed. The above preferred embodiments should be considered illustrative rather than restrictive, and it should be understood that those skilled in the art can make changes in these embodiments without departing from the scope of the present invention defined by the following claims.

Claims

1. A three-dimensional display device, characterized in that, it comprises: a backlight panel configured to convert the light beam emitted by a light source into a first collimated light beam; a spatial light modulator located in the propagation direction of the first collimated light beam, configured to load multi-view mixed image information onto the first collimated light beam by amplitude modulation to form a second collimated light beam; and a positive lens group located in the propagation direction of the second collimated light beam, configured to project the images of different views in the image carried by the second collimated light beam to their respective corresponding viewing positions, wherein, the positive lens group is a Fresnel lens group, wherein, the spatial light modulator includes a plurality of volume pixels, each volume pixel includes a plurality of sub-pixels, each sub-pixel corresponds to a different view, the Fresnel lens group includes a plurality of Fresnel lenses, and each Fresnel lens is configured to project the light beams from the sub-pixels corresponding to the same view among the plurality of volume pixels to the same viewing position, wherein, each Fresnel lens is divided into a plurality of regions, and each region is configured to project the light beams from the sub-pixels corresponding to the same view among the plurality of volume pixels to the same viewing position.

2. The device according to claim 1, wherein, the backlight panel includes: a light guide plate including a first microstructure located on the upper surface, lower surface or inside of the light guide plate, the first microstructure having a periodically distributed first unit, and the light beam emitted by the light source is scattered to the outside of the light guide plate by the first microstructure; and an optical film stacked with the light guide plate, including a second microstructure located on the surface of the optical film, the second microstructure having a periodically distributed second unit, and the light beam scattered to the outside of the light guide plate by the first microstructure is transformed into the first collimated light beam by the second microstructure.

3. The device according to claim 2, wherein, the first unit is one of a micro prism, a micro lens, a free-form surface lens or a pit.

4. The device according to claim 2, wherein, the second unit is one of a micro lens, a Fresnel lens or a thin film lens.

5. The device according to claim 2, wherein, the backlight panel further includes a light shielding plate, which includes a light shielding structure that matches and corresponds to the first microstructure and the second microstructure to filter out stray light emitted from the second microstructure.

6. The device according to claim 5, wherein the light shielding plate is disposed at one of the following positions: between the light guide plate and the optical film, inside the light guide plate, and inside the optical film.

7. The device according to claim 2, wherein, the light source is integrated in the device and is located at the side of the backlight panel.

8. The device according to claim 7, wherein, the light source is an LED line array light source.

9. The device according to claim 1, wherein, the spatial light modulator is a liquid crystal display unit.

10. The device according to claim 1, wherein, it further includes a light shielding plate located between the spatial light modulator and the Fresnel lens group.

11. The device according to claim 1, wherein, The light source is a white light source or a three-primary-color light source, and the device further includes a color filter stacked together with the spatial light modulator and the Fresnel lens group.

12. The device according to claim 11, wherein, the color filter is disposed between the spatial light modulator and the Fresnel lens group.

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