Autostereoscopic display device with image partitioning backlight

Abstract

A naked-eye stereoscopic image display device with image partitioning backlight is suitable for use with an imaging semi-reflective mirror. The display includes a main display module and a light-shielding module. The light-shielding module is superimposed on the light-incident or light-out side of the main display module. The display is divided into multiple blocks and switches in time-division manner, which is coordinated with the backlight to achieve the effect of image partitioning display. This solves the problem of image retention and crosstalk caused by insufficient response speed of the main display module when the left and right eye parallax images switch quickly. The brightness of the image can be adjusted by changing the display time of the display blocks.

Description

Technical Field

[0001] This invention relates to a naked-eye stereoscopic image display device, and more precisely, to a naked-eye stereoscopic image display device with backlit real image imaging. Prior Technology

[0002] As shown in Figures 1A and 1B, a conventional head-up display (HUD) uses a backlight 01 to emit a backlight beam. The backlight beam passes through the display panel 3 to form an image beam, which is then reflected by an imaging concave mirror 5. The imaging concave mirror 5 is a concave reflector, and the image of the display panel 3 forms a virtual image behind the imaging concave mirror 5. The backlight 01 forms a real image of the backlight in the optical path in front of the imaging concave mirror 5.

[0003] An imaging semi-reflective mirror is used to reflect a portion of the image beam from an imaging concave mirror to the viewer's eye, while allowing a portion of the light from objects in front of it to pass through to the viewer's eye. The imaging semi-reflective mirror can be, for example, a windshield WS as shown in Figure 1A or a superimposed mirror C as shown in Figure 1B. The virtual image behind the imaging concave mirror 5 is reflected by the imaging semi-reflective mirror (windshield or superimposed mirror) to form a virtual image G_im on the imaging semi-reflective mirror, away from the viewer. The real image of the backlight source in front of the imaging concave mirror 5 is reflected by the imaging semi-reflective mirror and focused to form a real image of the backlight source closer to the viewer on the imaging semi-reflective mirror, which is the eyebox EB.

[0004] When the viewer's eyes are at the eye box position, which is the actual focal point of the light emitted by the backlight, the brightest and clearest virtual image can be seen.

[0005] In order for the backlight to form a real image of the backlight in front of the imaging concave mirror, the distance between the backlight and the imaging concave mirror needs to be greater than the focal length of the imaging concave mirror. This makes it even more difficult in the already limited space of a car dashboard.

[0006] As shown in Figure 1C, a conventional directional backlit autostereoscopic head-up display device uses a directional backlight array as the backlight 01, paired with a fast-response display panel 3. The directional backlight array 01 projects a directional backlight beam B onto the display panel 3. The display panel 3 rapidly switches between displaying the left-eye parallax image and the right-eye parallax image. After the directional backlight beam B penetrates the display panel 3, it forms a directional image beam D carrying image information. The directional image beam D is then reflected by the imaging concave mirror 5 and the imaging semi-reflective mirror 7, forming a real backlight image, i.e., the eyebox array EBA, on the side of the imaging semi-reflective mirror 7 facing the viewer, and a virtual image G_im on the side of the imaging semi-reflective mirror 7 away from the viewer. The viewer's left and right eyes see the left and right parallax image virtual images G_im respectively within the area of ​​the eyebox array EBA, which the brain interprets as a stereoscopic image.

[0007] The backlight array is reflected by the imaging concave mirror 5 to form a real image of the backlight array in front of the imaging concave mirror 5. Then, it is reflected by the imaging semi-reflecting mirror 7 and projected onto the viewer's eye box array EBA. The left and right eye parallax images of the display panel 3 are reflected by the imaging concave mirror 5 to form virtual images of the left and right eye parallax images located behind the imaging concave mirror 5. Then, they are reflected by the imaging semi-reflecting mirror 7 to become virtual images of the left and right eye parallax images G_im that are far away from the viewer from the imaging semi-reflecting mirror 7. The eye tracking module 6 detects the relative position information of the viewer's left and right eyes and the eye tracking module. The control and calculation module 61 receives the detection information from the eye tracking module 6 and, through identification, calculation, table lookup or inference, obtains the viewer's left eye position E_L and right eye position E_R in space. Then, from the left and right eye positions, the corresponding left eye small eye box EB_L and right eye small eye box EB_R in the eye box array EBA are obtained. And from the left and right eye small eye boxes, the left eye backlight Led_L and right eye backlight Led_R are obtained. When display panel 3 displays the left eye parallax image, the left eye backlight Led_L is lit; when displaying the right eye parallax image, the right eye backlight Led_R is lit. The switching time between the two images is shorter than the persistence of vision in the human eye, allowing the left and right eyes to continuously see the left and right parallax images respectively.

[0008] The time interval between switching between the left-eye parallax image and the right-eye parallax image on display panel 3 is very short, while the liquid crystal needs time to react. If some liquid crystal pixels cannot complete the switching in time, the other eye will see the unswitched area (part of the previous image) and the area that is switching, causing crosstalk and ghosting.

[0009] In summary, to achieve bright and clear naked-eye stereoscopic images, it is necessary to address the required distance between the backlight and the imaging concave mirror, as well as the crosstalk and ghosting problem caused by the display panel's insufficient switching speed. Summary of the Invention

[0010] To achieve the above objectives, the present invention provides a naked-eye stereoscopic image display device.

[0011] A naked-eye stereoscopic image display device, suitable for use with an imaging semi-reflective mirror, and comprising:

[0012] The backlight module comprises a backlight array consisting of a plurality of backlight sources, which emits a backlight beam;

[0013] An off-axis hyperbolic mirror module includes a first curved mirror and a second curved mirror, which are offset from each other's optical axes. The first curved mirror and the second curved mirror reflect the backlight beam in sequence to form a directional backlight beam.

[0014] The display includes a main display module and a light-shielding module that are stacked together. The main display module alternately displays the left-eye parallax image and the right-eye parallax image. A directional backlight beam penetrates the display to form an image beam.

[0015] An imaging concave mirror reflects the image beam;

[0016] The eye-tracking module detects the relative position information of the viewer's left and right eyes to the eye-tracking module;

[0017] The control and computing module obtains the detection information from the eye-tracking module to determine the position of the viewer's left and right eyes in space.

[0018] Among them, the off-axis hyperbolic mirror module is used to enable the backlight module to form a virtual image of the backlight array. The equivalent distance between the virtual image of the backlight array and the imaging concave mirror is greater than the focal length of the imaging concave mirror. The backlight beam emitted from the virtual image of the backlight array is reflected by the imaging concave mirror and the imaging semi-reflective mirror, and then projected and converged on the backlight focusing surface of the imaging semi-reflective mirror on the side closer to the viewer to form a real image of the backlight module. This defines an eye box array, which contains a plurality of small eye boxes.

[0019] In addition, the equivalent distance between the main display module and the imaging concave mirror is less than the focal length of the imaging concave mirror. The left-eye parallax image and the right-eye parallax image are located on the side of the imaging semi-reflective mirror away from the eye box array, forming a left-eye parallax image virtual image and a right-eye parallax image virtual image, respectively.

[0020] In addition, the polarizer near the light-incident side of the display is a reflective polarizer, and there is only one polarizer between a liquid crystal layer of the main display module and a liquid crystal layer of the light-shielding module.

[0021] In addition, the main display module defines a plurality of display blocks, and the light-blocking module defines a plurality of switching blocks. Each switching block corresponds to a display block. When the main display module displays an image, at least one switching block is switched in a time-division manner to control the display block to project the image beam in a time-division manner. The remaining switching blocks block the main display module blocks that are still in the switching state or have not yet been switched.

[0022] In addition, when the main display module displays the image of one eye, at least one switching block is switched in a time-division manner to control the time-division projection of the image beam of the display block, while the remaining switching blocks block the display block that is still displaying the image of the other eye.

[0023] In addition, by matching each display block with backlights in the same or different positions, more small eye boxes can be defined outside the eye box array space on both sides of the backlight focusing surface. This includes the original eye box array, defining a wider range of extended eye box arrays, allowing the complete left-eye parallax image virtual image or right-eye parallax image virtual image to be seen even in spatial positions far from the backlight focusing surface.

[0024] In addition, switching or expanding the eye box array allows the small eye boxes in different positions to move up and down, left and right, and forward and backward to different positions according to the viewer's eyes.

[0025] In addition, the control and calculation module derives the left and right eye boxes based on the left eye position, the right eye position, and the extended eye box array. Then, it obtains the corresponding left and right eye matrices based on the small eye box-display block-backlight matrix table. The left and right eye matrices contain their corresponding display blocks, switching blocks, and backlights. The display blocks, switching blocks, and backlights are controlled to illuminate the left and right eye parallax images, respectively.

[0026] In addition, the corresponding small eye box is lit up according to the position of the left eye or the right eye. By switching different small eye boxes to correspond to the eye displacement, which includes displacement in two-dimensional or three-dimensional directions, the position of the eye can be tracked to project images.

[0027] In addition, the backlight module includes a conical light cup array, which is composed of conical light cups with different tilt angles. The tilt angle of each conical light cup increases as it moves away from the center of the array.

[0028] In addition, the backlight module includes a conical light cup array, a steering lens array, and a condenser lens array, arranged sequentially from the light-emitting side of the backlight array.

[0029] In addition, the second curved mirror is a concave mirror, and the first curved mirror is a concave mirror, a convex mirror, or a plane mirror. After the backlight module is reflected by the first curved mirror, the image position is within the focal length of the second curved mirror.

[0030] In addition, the optical path from the backlight module to the first curved mirror and the optical path from the second curved mirror to the display module may or may not intersect each other.

[0031] In addition, a light-shielding module is superimposed on the light-incident or light-exit side of the main display module.

[0032] In addition, the main display module and the light-shielding module are bonded together with optical adhesive. There is no polarizer between the optical adhesive and the liquid crystal layer of the main display module, or there is no polarizer between the optical adhesive and the liquid crystal layer of the light-shielding module.

[0033] In addition, adjusting the duration of the switching block or the duration of the backlight can control the brightness of the left-eye and right-eye parallax images.

[0034] In addition, the liquid crystal switching speed of the main display module is slower than that of the light-shielding module.

[0035] In addition, the viewer uses 2n+1 adjacent small eye boxes in the left-right or up-down directions to correspond to a single eye, where n>0 and n is a positive integer. The small eye box in the center of the multiple small eye boxes is aligned with the pupil, and the 2n small eye boxes other than the central small eye box are located on the upper and lower or left and right sides of the central small eye box.

[0036] In addition, the main display module alternately displays the left-eye parallax image and the right-eye parallax image, and the switching interval between the projection of image light to the same eye in each display block is less than 41.67ms.

[0037] In addition, the imaging semi-reflective mirror is a windshield or superimposed mirror, used to reflect part of the image beam from the imaging concave mirror to the viewer's eyes, while allowing part of the light from the scene in front of it to pass through to the viewer's eyes. Simple Explanation of the Diagram

[0038] Figures 1A and 1B are schematic diagrams of a conventional backlit head-up display device equipped with an imaging semi-reflective mirror.

[0039] Figure 1C is a schematic diagram of a conventional directional backlit naked-eye stereoscopic image head-up display device.

[0040] Figures 2A, 2B, 2C, and 2D are schematic diagrams of off-axis hyperbolic mirror modules.

[0041] Figure 3A is a schematic diagram of a backlit display device equipped with an off-axis hyperbolic mirror module.

[0042] Figure 3B is a schematic diagram of the diffusion angle of the backlight beam with or without passing through the off-axis hyperbolic mirror module.

[0043] Figures 4A, 4B, 4C, and 4D are schematic diagrams of a directional backlight array module.

[0044] Figures 5A, 5B, and 5C are schematic diagrams of a backlight array module with a built-in lens.

[0045] Figure 6A is a schematic diagram of a display device for real image imaging using a backlight array paired with an off-axis hyperbolic mirror module.

[0046] Figure 6B is another schematic diagram of a display device for real image imaging with a backlight array paired with an off-axis hyperbolic mirror module.

[0047] Figure 7 is a schematic diagram of a naked-eye stereoscopic image display device.

[0048] Figures 8A and 8B are schematic diagrams showing the correspondence between the eye box array and the positions of the left and right eyes.

[0049] Figures 8C and 8D are schematic diagrams showing multiple small eye boxes corresponding to the position of a single eye.

[0050] Figure 9 is a schematic diagram of the main display module switching image under ideal conditions.

[0051] Figure 10A is a schematic diagram of the liquid crystal pixel switching time.

[0052] Figure 10B is a schematic diagram of the pixel switching state of a liquid crystal display panel.

[0053] Figure 11A is a schematic diagram of the main display module and the light-shielding module.

[0054] Figure 11B is a schematic diagram of the main display module and the light-shielding module stacked together.

[0055] Figure 11C shows a schematic diagram of the response time of IPS liquid crystal and TN liquid crystal.

[0056] Figures 11D, 11E, 11F, 11G, 11H, and 11I are schematic diagrams of the detailed structure of the superimposed main display module and the light-shielding module.

[0057] Figure 12A is a schematic diagram of the pixel conversion cycle of the main display module.

[0058] Figure 12B is a schematic diagram showing the multiple blocks defined by the main display module and the light-shielding module.

[0059] Figure 13 is a schematic diagram of the switching timing of multiple blocks of the main display module, the light shielding module and the backlight module.

[0060] Figure 14 is a schematic diagram showing the switching between the main display module, the light-shielding module, and the backlight module.

[0061] Figure 15 is a schematic diagram of the images seen by the left and right eyes at different time sequences.

[0062] Figure 16A is a schematic diagram of the real image imaging of the backlight module and the virtual image imaging of the main display module.

[0063] Figures 16B and 16C are schematic diagrams of the partitioned real image imaging of the backlight module and the partitioned virtual image imaging of the main display module.

[0064] Figures 17A, 17B, and 17C are schematic diagrams of the spatial optical path of the first backlight and each display block.

[0065] Figures 17D and 17E are schematic diagrams of the spatial optical path intersection of the first backlight and the main display module in a zoned configuration.

[0066] Figures 18A, 18B, and 18C are schematic diagrams of the spatial optical path of the second backlight and each display block.

[0067] Figures 18D and 18E are schematic diagrams of the spatial optical path intersection of the second backlight and the main display module in a zoned configuration.

[0068] Figures 19A, 19B, and 19C are schematic diagrams of the spatial optical path of the third backlight and each display block.

[0069] Figures 19D and 19E are schematic diagrams of the spatial optical path intersection of the third backlight and the main display module in a zoned configuration.

[0070] Figure 20A is a schematic diagram of the spatial optical path of the first backlight and the first display block.

[0071] Figure 20B is a schematic diagram of the spatial optical path of the second backlight and the second display block.

[0072] Figure 20C is a schematic diagram of the spatial optical path of the third backlight and the third display block.

[0073] Figures 20D and 20E are schematic diagrams of the spatial optical path intersection of the backlight module group and the main display module group.

[0074] Figure 21A is a schematic diagram of the spatial optical path of the third backlight and the first display block.

[0075] Figure 21B is a schematic diagram of the spatial optical path of the second backlight and the second display block.

[0076] Figure 21C is a schematic diagram of the spatial optical path of the first backlight and the third display block.

[0077] Figure 21D is a schematic diagram of the spatial optical path intersection of the backlight module group and the main display module group in Figure 21E.

[0078] Figures 22A and 22B are schematic diagrams of a naked-eye stereoscopic image display device paired with an imaging semi-reflective mirror.

[0079] Figures 23A and 23B are schematic diagrams of the extended eye box array.

[0080] Figure 24A is an example schematic diagram of the backlight module, the main display module, and the light-shielding module.

[0081] Figures 24B and 24C are schematic diagrams of examples of extended eye box arrays.

[0082] Figures 25A and 25B are schematic diagrams of the corresponding matrix table of small eye box - display block - backlight.

[0083] Figures 26A, 26B, 26C, and 26D are schematic diagrams illustrating the switching sequence of the left and right eye boxes, the main display module display area, the light-shielding module switching area, and the backlight of the backlight module in a naked-eye stereoscopic image display device. Implementation

[0084] The following description is based on the light emission direction of the light-emitting surface as the front, in order to conform to the common understanding of those skilled in the art.

[0085] To extend the equivalent distance of the backlight to meet the condition that the object distance for real image imaging is greater than the focal length of the concave mirror, and to reduce space usage and form a directional beam, an off-axis hyperbolic mirror module 2 can be used, as shown in Figures 2A-2D. The off-axis hyperbolic mirror module 2 includes a first curved mirror 21 and a second curved mirror 22 that are offset from each other's optical axes. The center MC of the two curved mirrors 21 and 22 is not on the optical axis OA of the other. Using a smaller area backlight module 1, after reflection by the first curved mirror 21 and the second curved mirror 22, a magnified and farther backlight virtual image is formed behind the second curved mirror 22. The position of the backlight virtual image falls outside the focal length of the imaging concave mirror 5, and then the imaging concave mirror 5 forms the backlight real image.

[0086] The light emitted from the backlight of the backlight module 1 is projected onto the first curved mirror 21, then reflected by the first curved mirror 21 to the second curved mirror 22, and then reflected by the second curved mirror 22 and projected onto the display panel 3. In order to form a backlight virtual image that is far away from the imaging concave mirror, the second curved mirror 22 can be a concave mirror.

[0087] After the backlight module 1 is reflected by the first curved mirror 21, whether the real image of the backlight source formed in front of the first curved mirror 21 or the virtual image of the backlight source formed behind the first curved mirror 21, it must be between the focal points of the second curved mirror 22 to be reflected by the second curved mirror 22 to form the virtual image 1_im of the backlight source behind the second curved mirror 22. Therefore, the first curved mirror 21 can be a concave mirror, as shown in Figures 2A and 2C; it can also be a convex mirror, as shown in Figures 2B and 2D; or a plane mirror, as long as it can be imaged within the focal length of the second curved mirror 22. Then, it is reflected by the second curved mirror 22 to form the virtual image 1_im of the backlight source behind the second curved mirror 22, as shown in Figure 3A.

[0088] The first light path from the backlight to the first curved mirror 21 and the second light path from the second curved mirror 22 to the display panel can intersect each other, as shown in Figures 2A and 2B, or they can not intersect each other, as shown in Figures 2C and 2D.

[0089] Figure 3A shows a display device that combines an off-axis hyperbolic lens module 2 with a smaller backlight module 1, which has the advantages of reducing the overall space and being able to view clear and bright images at the eye box EB where the backlight real image is formed.

[0090] As shown in Figure 3B, the equivalent backlight of the display panel 3 is the backlight virtual image 1_im formed behind the second curved mirror 22. The mirror diameter of the second curved mirror 22 is smaller than the beam cross section of the backlight virtual image 1_im diffused to the second curved mirror 22. That is, the boundary 221 of the second curved mirror 22 restricts the beam diffusion angle of the backlight virtual image 1_im, which is equivalent to forming a directional backlight beam B.

[0091] In the design of the backlight module, LEDs can be used as the backlight source, forming a backlight array 11 as shown in Figure 4A, and then paired with a conical light cup array 12. The conical light cup array 12 is composed of a plurality of conical light cups, which can be hollow light cups with a reflective film coated on the surface, or solid light guides that transmit light. The conical light cup array is set on the light-emitting side of the backlight array 11 to reduce the light source diffusion angle and form a directional backlight.

[0092] Alternatively, as shown in Figure 4B, a conical light cup array 12, a steering lens array 13T, and a condenser lens array 13L are sequentially arranged on the light-emitting side of the backlight array 11. The steering lens array 13T is used to concentrate the projection angle of each light source, and the condenser lens array 13L further reduces the diffusion angle of the light source, forming a directional backlight.

[0093] Alternatively, it could be a conical light cup array 12 as shown in Figure 4C, plus a focusing lens 14. Or it could be a tilted conical light cup array 12 as shown in Figure 4D, containing conical light cups with different tilt angles. The tilt angle of each light cup increases as it moves away from the center of the array, thereby reducing the diffusion angle of the light source and concentrating the projection angle of each light source.

[0094] Alternatively, LEDs 13 with built-in lenses can be used on a planar substrate to form a backlight array 11, as shown in Figure 5A. Or, LEDs 13 with built-in lenses can be used on a curved substrate to form a backlight array 11, as shown in Figure 5B. Or, LEDs 13 with built-in lenses can be used on a planar substrate to form a backlight array 11, with a condenser lens 14 added in front of the backlight array 11, as shown in Figure 5C.

[0095] As shown in Figure 6A, the backlight array 10 of the backlight module is formed outside the focal length of the imaging concave mirror by the imaging of the off-axis hyperbolic mirror module 2 (virtual image 10_im of the backlight array). The virtual image 10_im is then projected onto the imaging semi-reflective mirror 7 (windshield) by the imaging concave mirror 5 (real image 10_re of the backlight array), and reflected by the imaging semi-reflective mirror 7 (windshield) to the backlight focusing surface BFP, forming an eyebox array EBA. The backlight array 10 contains a plurality of backlights 1. Each backlight 1, after passing through the off-axis hyperbolic mirror module 2 and the imaging concave mirror 5, forms an independent small eyebox EB. All the small eyeboxes EB are combined to form the eyebox array EBA. As shown in Figure 6B, the viewer's eye can see the virtual image G_im, which is far from the viewer, through the imaging semi-reflective mirror 7 within this eyebox array EBA.

[0096] As shown in Figure 7, a naked-eye stereoscopic image display device includes a backlight module 1, an off-axis hyperbolic mirror module 2, a display 3, an imaging concave mirror 5, and an eye-tracking module 6; the backlight module 1, the display 3, and the eye-tracking module 6 are all connected to the control and computing module 61 to transmit detection information and control signals.

[0097] The backlight module 1 includes a backlight array 11 composed of a plurality of backlights, which emits a backlight beam B.

[0098] The off-axis hyperbolic mirror module 2 includes a first curved mirror 21 and a second curved mirror 22 for reflecting the backlight beam B.

[0099] The display 3 (as shown in Figure 11A) includes a main display module 31 and a light-shielding module 4 that are stacked together.

[0100] The main display module 31 alternately displays the left-eye parallax image and the right-eye parallax image, defining a plurality of display blocks; the light-blocking module 4 defines a plurality of switching blocks, each switching block corresponding to a display block, alternately blocking light penetration;

[0101] The backlight beam B penetrates the display 3 to form the image beam D.

[0102] The imaging concave mirror 5 reflects the image beam D.

[0103] The eye-tracking module 6 detects the relative positions of the viewer's left and right eyes in space relative to the eye-tracking module;

[0104] The control and calculation module 61 receives the detection information from the eye tracking module 6, and through identification, calculation, table lookup or inference, determines the viewer's left eye position E_L and right eye position E_R in space. The values ​​can be coordinates of a rectangular coordinate system, a cylindrical coordinate system, a spherical coordinate system or other coordinate systems. Then, from the left eye position E_L and the right eye position E_R, the corresponding left eye small eye box EB_L and right eye small eye box EB_R located in the eye box array EBA are obtained, and from the left eye small eye box EB_L and the right eye small eye box EB_R, the corresponding left eye backlight Led_L and right eye backlight Led_R are obtained.

[0105] The light emitted from the backlight array 11 of the backlight module 1 is reflected by the off-axis hyperbolic mirror module 2, the imaging concave mirror 5, and the imaging semi-reflective mirror 7. The light converges at the backlight focusing surface BFP on the side of the imaging semi-reflective mirror 7 closest to the viewer, forming a real image of the backlight array, which is an eyebox array EBA containing a plurality of small eyeboxes EB. The main display module 31 displays a parallax image for the left or right eye. The emitted light is reflected by the imaging concave mirror 5 and the imaging semi-reflective mirror 7, forming a virtual parallax image G_im for the left or right eye at the image focusing surface IFP on the side of the imaging semi-reflective mirror 7 furthest from the viewer.

[0106] When the main display module 31 displays the left-eye parallax image, the left-eye backlight LED_L is lit and the light-shielding module 4 switches between different switching blocks. When the main display module 31 displays the right-eye parallax image, the right-eye backlight LED_R is lit and the light-shielding module 4 switches between different switching blocks. The display blocks of the left-eye or right-eye parallax image can be displayed in a time-division manner, ensuring that both eyes continuously see a bright and clear left-eye or right-eye parallax image virtual image G_im without crosstalk or afterimages, thus forming stereoscopic vision.

[0107] Because the backlight module 1, combined with the off-axis hyperbolic lens module 2, forms a directional backlight beam, the small eyeboxes EB included in the eyebox array EBA are not only distributed on the backlight focusing surface BFP, but their effective area also extends to the front and back depth of the Z-axis in the direction of the viewer's eye line of sight. Different small eyeboxes EB can be switched to correspond to the current position of the eyes. The effective area of ​​the small eyebox EB shrinks as it moves forward and backward along the Z-axis, and shrinks further away from the backlight focusing surface BFP. In addition, by using each display block with at least one backlight in a different position, more small eyeboxes EB_V can be defined outside the space of the eyebox array EBA on both sides of the backlight focusing surface BFP. This forms a wider extended eyebox array EBA_V, which is similar to a combination of two trapezoidal solid structures joined together by their lower bases. It contains multiple small eyeboxes EB_V, so it can cover the possible range of eye movement when moving up and down, left and right, and forward and backward, providing a wide field of view naked-eye stereoscopic image display device.

[0108] The light-blocking module 4 switches between different switching blocks, switching one or more blocks at a time to block the display blocks of the main display module 31 that have not yet completed their conversion. As long as the display blocks that have not yet completed their conversion are not displayed, there will be no afterimages, and the left and right eyes can continue to see images without afterimages or crosstalk, thus achieving a high-quality naked-eye stereoscopic image display device.

[0109] Additionally, switching the on / off time interval of display blocks, the number of display blocks on, or the backlight illumination time interval can be used to adjust the brightness of the image. The more display blocks displayed simultaneously, or the longer the display time of each display block, the brighter the image will be.

[0110] The eye-tracking module 6 can utilize a combination of cameras, ultrasound, millimeter-wave radar, lasers, or other detectors to detect the relative position information of the viewer's left and right eyes relative to the eye-tracking module. The control and processing module 61 receives the detection information from the eye-tracking module 6 and, through identification, calculation, table lookup, or inference, determines the viewer's left eye position E_L and right eye position E_R in space. These values ​​can be coordinates in a Cartesian coordinate system, a cylindrical coordinate system, a spherical coordinate system, or other coordinate systems.

[0111] As shown in Figure 8A, disregarding the distribution of small eyeboxes along the Z-axis, and focusing only on the eyebox array EBA of the backlight focusing surface BFP, the eyebox array EBA is composed of many small eyeboxes. The control and calculation module 61 identifies the small eyeboxes EB_43 and EB_23 corresponding to the left-eye position E_L and right-eye position E_R, respectively, within the eyebox array EBA. When the main display module 31 displays the left-eye parallax image, the backlight Led_43 corresponding to small eyebox EB_43 is illuminated; when the main display module 31 displays the right-eye parallax image, the backlight Led_23 corresponding to small eyebox EB_23 is illuminated.

[0112] As shown in Figure 8B, when the viewer moves their head, the corresponding backlights Led_52 and Led_32 are switched on and lit according to the positions E_L' and E_R' after the eye movement, so that both eyes can continuously see the parallax image and form stereoscopic vision.

[0113] As shown in Figure 8C, one eye can also correspond to 2n+1 adjacent small eyeboxes EB in the eyebox array EBA, where n>0 and n is a positive integer. For example, one eye can correspond to 3 (n=1), 5 (n=2), or 7 (n=3) small eyeboxes. Taking 3 adjacent small eyeboxes as an example, the central small eyebox EB_93 and its two side small eyeboxes EB_83 and EB_103 are selected according to the position of the left pupil, and the central small eyebox EB_43 and its two side small eyeboxes EB_33 and EB_53 are selected according to the position of the right pupil. When the main display module 31 displays the left eye parallax image, the backlights Led_83, Led_93, and Led_103 corresponding to the small eye boxes EB_83, EB_93, and EB_103 are lit up simultaneously. When the main display module 31 displays the right eye parallax image, the backlights Led_33, Led_43, and Led_53 corresponding to the small eye boxes EB_33, EB_43, and EB_53 are lit up simultaneously.

[0114] As shown in Figure 8D, when the viewer's left pupil moves to the left to the position of the small eye box EB_103, and the right pupil moves to the left to the position of the small eye box EB_53, and then the three small eye boxes EB_93, EB_103, and EB_113 are redefined according to the position of the left pupil, and the three small eye boxes EB_43, EB_53, and EB_63 are redefined according to the position of the right pupil, it is possible to ensure that both the left and right eyes continuously see the parallax image separately. It can also reduce the image interruption caused by the horizontally adjacent small eye boxes not having enough time to switch when the eyes move quickly laterally, and avoid image flicker.

[0115] Using 2n+1 adjacent eyeboxes, they can be configured in the left-right or up-down direction. The eyebox located in the center is aligned with the pupil of the eye to dynamically switch eyeboxes. The adjacent eyeboxes on the left and right or up and down serve as a buffer when tracking eye movement.

[0116] When the human eye looks at an object, the image of the object is formed on the retina. The optic nerve receives the stimulus and converts it into a nerve impulse in about 1-2 ms. The impulse is then transmitted to the brain, allowing the person to perceive the image of the object. However, when the object is removed, the impression of the object on the optic nerve does not disappear immediately, but continues for 0.1-0.4 seconds. This property is called "persistence of vision".

[0117] When the transition speed of static images is faster than 10-16 fps (frames per second), humans perceive the images as continuous and flicker-free. However, for moving images, the transition speed needs to be 24-60 fps for the brain to perceive the images as smooth. Therefore, the interval between each image seen by the eye must be less than 1 / 24 to 1 / 60 of a second, that is, the image interruption time Tg must be less than 41.67 ms to 16.78 ms. The slower the movement of objects in the scene, the longer the acceptable image interruption time Tg, and the closer it is to 41.67 ms. The faster the movement of objects in the scene, the shorter the acceptable image interruption time Tg, and the closer it is to 16.78 ms, in order to perceive the images as continuous and flicker-free.

[0118] As shown in Figure 9, when switching between displaying left and right eye images using the same liquid crystal display panel, the image interruption time Tg between two consecutive left eye images or two consecutive right eye images must be less than or equal to 1 / 24 to 1 / 60 seconds, that is, ≤41.67ms to 16.78ms.

[0119] Ideally, when the entire image on the LCD panel completely switches to the left-eye image, the backlight array also switches to the corresponding light source for the left eye; when the entire image on the LCD panel then completely switches to the right-eye image, the backlight array also switches to the corresponding light source for the right eye, and so on.

[0120] As shown in Figure 10A, in actual operation, the liquid crystal switching requires time. The liquid crystal response time is the rise time Tr + fall time Tf, which respectively refer to the brightness range of a pixel from 10% to 90% and from 90% to 10%. This switching does not occur simultaneously for all pixels on the screen, but rather through sequential scanning and switching, resulting in a time difference in the switching time between pixels in different areas.

[0121] As shown in Figure 10B, current automotive-grade LCD panels often struggle to completely switch all pixels of the entire image to the image of the other eye and back to the original eye within the image interruption time Tg, and to allow backlight to penetrate the entire display panel for at least 2ms to stimulate the optic nerve and convert it into nerve impulses to display a complete image. During this process, some pixels (pix_t) will remain in a transition state, and some pixels (pix_p) may even be in the previous image state.

[0122] At this time, once the light source corresponding to the backlight array is lit, the viewer may simultaneously see an image that is a mixture of the transition state pixel pix_t and the previous state pixel pix_p, which is called ghosting or crosstalk. This greatly affects the quality of the viewed image and may also make people feel dizzy and uncomfortable.

[0123] As shown in Figures 11A and 11B, in order to solve the aforementioned problem, a light-shielding module 4 is superimposed on the light-incident side or the light-outcident side of the main display module 31. In this embodiment, the light-shielding module 4 is also a display module. The two display modules are bonded together with optical adhesive OCA (Optical Clear Adhesive). The backlight beam B must pass through both the main display module 31 and the light-shielding module 4 simultaneously to generate the image beam D.

[0124] When the light-incident side of the main display module 31 is superimposed with the light-shielding module 4, the multiple switching blocks of the light-shielding module 4 are switched in a time-division manner to control the area where the backlight beam B can penetrate the main display module 31, so that the image of a specific display area forms an image beam D and is projected.

[0125] When the light-emitting side of the main display module 31 is superimposed with the light-shielding module 4, the multiple switching blocks of the light-shielding module 4 are switched in a time-division manner to control the image beam D to only penetrate a specific display area and project forward.

[0126] For ease of explanation, the following description will only use the method of stacking the light-shielding module 4 on the light-incident side of the main display module 31 as the display 3.

[0127] As shown in Figure 11C, the main display module 31 uses, for example, an IPS (In-Plane Switching) color liquid crystal display panel with a wide color gamut, while the light-shielding module 4 uses a liquid crystal material with a faster response time, such as a TN (Twisted Nematic) black and white liquid crystal display panel. The response time (Tr+Tf) of TN liquid crystal is shorter than that of IPS liquid crystal.

[0128] As shown in Figure 11D, the stacked detailed structure includes a lower polarizer 32, a liquid crystal layer 33, and an upper polarizer 34 in the main display module 31, and a lower polarizer 42, a liquid crystal layer 43, and an upper polarizer 44 in the light-shielding module 4. Optical adhesive (OCA) connects the main display module 31 and the light-shielding module 4. The lower polarizer 32 of the main display module 31 and the upper polarizer 34 of the light-shielding module 4 are polarizers with the same polarization direction. Removing one of them maintains the original function, thereby reducing light source loss and cost. As shown in Figure 11E, the upper polarizer 44 of the light-shielding module 4 is removed; or as shown in Figure 11F, the lower polarizer 32 of the main display module 31 is removed.

[0129] In a display system that projects parallax images for both eyes, the backlight brightness is also divided over time due to the timing of the switching, requiring a high-brightness backlight module 1. However, about 50% of the backlight beam B projected by the backlight module 1 has a different polarization direction than the lower polarizer 42 and is absorbed by it. The remaining about 50% of the light with the same polarization direction as the lower polarizer 42 passes through the lower polarizer 42 and enters the liquid crystal layer 43. Under the illumination of the backlight beam B, the lower polarizer 42 absorbs nearly half of the energy of the backlight beam B, causing the temperature to rise rapidly and easily damaging the light-shielding module 4.

[0130] Therefore, the lower polarizer 42 closest to the light-incident side (display 3) can be replaced with a reflective polarizer 45. This allows light with a polarization direction different from that of the lower polarizer 42 to be reflected and not absorbed by the lower polarizer 42, significantly reducing the temperature of the light-shielding module 4 and the main display module 31. This allows the use of a higher brightness backlight module, increasing the display brightness, while preventing the light-shielding module 4 from being damaged by high temperatures. Figure 11G shows the replacement of the lower polarizer 42 in Figure 11D with a reflective polarizer 45, Figure 11H shows the replacement of the lower polarizer 42 in Figure 11E with a reflective polarizer 45, and Figure 11I shows the replacement of the lower polarizer 42 in Figure 11F with a reflective polarizer 45.

[0131] If the display 3 is stacked such that the light-shielding module 4 is stacked on the light-emitting side of the main display module 31, then the lower polarizer 32 closest to the light-incident side is replaced with a reflective polarizer 45.

[0132] As shown in Figure 12A, the liquid crystal pixel conversion cycle curve of the main display module 31 is such that if one complete cycle of the liquid crystal pixel conversion of the main display module 31 is T, then the time from the moment the image light is projected onto the left eye to the moment the next image light is projected onto the left eye is 2T. As shown in Figure 12B, the main display module 31 is a color liquid crystal display panel, for example, defined as three display blocks: the first display block IPS_1, the second display block IPS_2, and the third display block IPS_3. Each display block contains multiple pixels. When a pixel is switched to ON, backlight is transmitted, displaying the set color and brightness; when a pixel is switched to OFF, it is opaque. The light-shielding module 4 is a monochrome LCD display panel, which can also be defined as three switching blocks of the same size, namely the first switching block TN_1, the second switching block TN_2, and the third switching block TN_3. The first switching block TN_1 corresponds to the first display block IPS_1, the second switching block TN_2 corresponds to the second display block IPS_2, and the third switching block TN_3 corresponds to the third display block IPS_3. Each switching block can contain multiple pixels or a single pixel. When a pixel is switched to ON, light can pass through, and when a pixel is switched to OFF, it is opaque.

[0133] As shown in Figure 13, the left eye image is displayed first; after the liquid crystal of the first display block IPS_1 is switched to ON, the first switching block TN_1 and the left eye backlight are switched to ON; then, the left eye backlight and the first switching block TN_1 are switched to OFF, and the liquid crystal of the first display block IPS_1 is switched to OFF.

[0134] The timing of IPS_2 is slightly slower than that of IPS_1. The switching timing of the second display block IPS_2, the second switching block TN_2, and the left eye backlight is analogous to that of the first display block IPS_1, the first switching block TN_1, and the left eye backlight.

[0135] The timing of IPS_3 is slightly slower than that of IPS_2. The switching timing of the third display block IPS_3, the third switching block TN_3, and the left eye backlight is analogous to that of the first display block IPS_1, the first switching block TN_1, and the left eye backlight.

[0136] After the liquid crystal of the first display block IPS_1 is switched to OFF, the right eye image is then displayed; after the liquid crystal of the first display block IPS_1 is switched to ON, the first switching block TN_1 and the right eye backlight are switched to ON; then, the right eye backlight and the first switching block TN_1 are switched to OFF, and the liquid crystal of the first display block IPS_1 is switched to OFF.

[0137] After the liquid crystal of the second display block IPS_2 is switched to OFF, the right eye image is then displayed; the switching sequence of the second display block IPS_2, the second switching block TN_2, and the right eye backlight is analogous to the aforementioned first display block IPS_1, first switching block TN_1, and right eye backlight.

[0138] After the liquid crystal of the third display block IPS_3 is switched to OFF, the right eye image is then displayed; the switching sequence of the third display block IPS_3, the third switching block TN_3, and the right eye backlight is analogous to the aforementioned first display block IPS_1, first switching block TN_1, and right eye backlight.

[0139] The switching sequence is: IPS_1 → IPS_2 → IPS_3 → IPS_1, switching a single block each time in a loop; or switching multiple blocks each time, for example, switching two blocks each time: IPS_1 & IPS_2 → IPS_2 & IPS_3 → IPS_3 & IPS_1 → IPS_1 & IPS_2, and so on.

[0140] When the image of the display area is in the process of switching or not switching (the image of the previous view), turn off the corresponding backlight or the corresponding switching area until the image switching is complete, and then turn on the corresponding switching area and the corresponding backlight to avoid casting afterimages.

[0141] Generally speaking, the ON time of a TN switching block is shorter than that of an IPS display block, and the ON time of the backlight is shorter than that of each TN switching block. The time interval between two backlight beams passing through the same eye from one pixel to the other in an IPS display block needs to be less than the image interruption time Tg (16.78ms~41.67ms). In other words, the switching interval between the projection of the image beam from each display block to the same eye needs to be less than Tg to meet the requirements of visual persistence and ensure smooth dynamic images.

[0142] The backlight illuminates the entire display area. The IPS display area, whether switching or not (the image of the previous view), is blocked by the TN switching area in the OFF state, preventing the backlight from penetrating and thus preventing the viewer from seeing afterimages and crosstalk.

[0143] As shown in Figure 14, in the first 1 / 3 T (=1 / 6 × 2T) time period, the first display block IPS_1 has completed the left eye image conversion, and the backlight of the corresponding left eye small eye box is lit. However, only the backlight beam that penetrates the first switching block TN_1 penetrates the first display block IPS_1 to form the left eye IPS_1 image beam.

[0144] During the second 1 / 3 T time period, the second display block IPS_2 has completed the left eye image conversion, and the backlight of the corresponding left eye small eye box is lit. However, only the backlight beam that penetrates the second switching block TN_2 penetrates the second display block IPS_2 to form the left eye IPS_2 image beam.

[0145] During the third 1 / 3 T time period, the third display block IPS_3 has completed the left eye image conversion, and the backlight of the corresponding left eye small eye box is lit. However, only the backlight beam that penetrates the third switching block TN_3 penetrates the third display block IPS_3 to form the left eye IPS_3 image beam.

[0146] During the fourth 1 / 3 T time interval, the first display block IPS_1 has completed the right eye image conversion, and the backlight of the corresponding right eye small eye box is lit. However, only the backlight beam that penetrates the first switching block TN_1 penetrates the first display block IPS_1 to form the right eye IPS_1 image beam; this cycle continues.

[0147] The projection effect in Figure 14 is shown in Figure 15. During the first 1 / 3 T time period, only the image of the first display block IPS_1 was projected to the left eye, and no image was projected to the right eye; During the second 1 / 3 T time period, only the image of the second display block IPS_2 was projected to the left eye, and no image was projected to the right eye; During the third 1 / 3 T time period, only the image of the third display block IPS_3 was projected to the left eye, and no image was projected to the right eye; During the fourth 1 / 3 T time period, no image was projected to the left eye; only the image of the first display block IPS_1 was projected to the right eye. During the fifth 1 / 3 T time period, no image was projected to the left eye; only the image of the second display block IPS_2 was projected to the right eye. During the sixth 1 / 3 T time period, no image was projected to the left eye; only the image of the third display block IPS_3 was projected to the right eye. During the seventh 1 / 3 T time period, only the image of the first display block IPS_1 is projected to the left eye, and no image is projected to the right eye; the projection effect of the seventh 1 / 3 T time period is the same as that of the first 1 / 3 T time period, and then this cycle continues.

[0148] The left eye sequentially sees the display blocks IPS_1, IPS_2, and IPS_3 of the left-eye image. The images of each display block combine to form a complete left-eye image. Then, within the subsequent 16.78ms to 41.67ms, the display blocks of the left-eye image are seen again sequentially. The interval between the two left-eye images of each display block is shorter than the time of visual persistence. Similarly, the right eye sequentially sees the display blocks IPS_1, IPS_2, and IPS_3 of the right-eye image. The interval between the two right-eye images of each display block is also shorter than the time of visual persistence. Both the left and right eyes can form continuous and smooth images.

[0149] Figures 16A, 16B, and 16C are imaging diagrams of the backlight module 1 and the main display module 31. The white area of ​​the backlight module 1 is the area where the LEDs are lit, which also corresponds to the small eye boxes of the eye box array EBA that are lit. The white area of ​​the main display module 31 is the display area that is switched to ON, which also corresponds to the parallax image virtual image G_im that can be seen on the image focusing surface IFP.

[0150] As shown in Figure 16A, the backlight array 11 of the backlight module 1 emits a backlight beam B. The backlight beam B penetrates the light-shielding module 4 and forms an image beam D with the main display module 31. The image beam D is reflected by the imaging concave mirror 5. The backlight array of the backlight module 1 forms a real image (eyebox array EBA) on the backlight focusing surface BFP in front of the imaging concave mirror 5. The parallax image of the main display module 31 forms a parallax image virtual image G_im behind the imaging concave mirror 5.

[0151] As shown in Figure 16B, when only the second backlight Led_2 in the backlight module 1 is lit, and the light-shielding module 4 switches the first switching block TN_1 to ON, only the second small eye box EB_2 can clearly see the image virtual image IPS_1_im of the first display block IPS_1.

[0152] As shown in Figure 16C, when only the third backlight source Led_3 in the backlight module 1 is lit, and the light-shielding module 4 switches the second switching block TN_2 and the third switching block TN_3 to ON, only the third small eye box EB_3 can clearly see the image virtual images IPS_2_im and IPS_3_im of the second display block IPS_2 and the third display block IPS_3.

[0153] Figures 17A to 21E illustrate a small eyebox at a specific location constructed by a backlight and display blocks. The backlight shown in these figures is a surface light source, and the resulting real image is a surface real image on the focal plane.

[0154] As shown in Figures 17A to 17C, when only the first backlight LED_1 is lit, and it is used in conjunction with the display of the first display block IPS_1, the second display block IPS_2, and the third display block IPS_3, the image beam is focused on the individual light paths displayed by the first small eye box EB_1.

[0155] As shown in Figure 17D, by superimposing the light paths from Figures 17A to 17C, an intersecting region can be observed. In three-dimensional space, this region is a small eyebox with volume that gradually shrinks as it moves forward and backward, similar to the small eyebox EB_1V where the three diagonally lined regions intersect in Figure 17E. The backlight and display block combinations shown in Figures 17A to 17C, namely IPS_1 and Led_1; IPS_2 and Led_1; and IPS_3 and Led_1, when these three combinations are combined and displayed sequentially, the eye can see the images of IPS_1 to IPS_3 within the area of ​​this small eyebox EB_1V, meaning it can see the complete image.

[0156] As shown in Figures 18A to 18C, when only the second backlight LED_2 is lit, and it is used in conjunction with the display of the first display block IPS_1, the second display block IPS_2, and the third display block IPS_3, the image beam is focused on the individual light paths displayed by the second small eye box EB_2.

[0157] As shown in Figure 18D, superimposing the light paths from Figures 18A to 18C creates a small-eye box EB_2V, similar in state to the small-eye box EB_1V in Figures 17D and 17E, as shown by the intersection of the three diagonal lines in Figure 18E. The backlight and display block combinations shown in Figures 18A to 18C—namely, IPS_1 with LED_2; IPS_2 with LED_2; and IPS_3 with LED_2—when displayed sequentially, allow the eye to see the images of IPS_1 through IPS_3 within the area of ​​this small-eye box EB_2V; that is, to see the complete image.

[0158] As shown in Figures 19A to 19C, when only the third backlight LED_3 is lit, and it is used in conjunction with the display of the first display block IPS_1, the second display block IPS_2, and the third display block IPS_3, the image beam is focused on the individual light paths displayed by the third small eye box EB_3.

[0159] As shown in Figure 19D, superimposing the light paths from Figures 19A to 19C creates a small-eye box EB_3V, similar to the state of the small-eye box EB_1V in Figures 17D and 17E, as shown by the intersection of the three diagonal lines in Figure 19E. The backlight and display block combinations shown in Figures 19A to 19C—namely, IPS_1 and LED_3; IPS_2 and LED_3; and IPS_3 and LED_3—when displayed sequentially, allow the eye to see the images of IPS_1 through IPS_3 within the area of ​​this small-eye box EB_3V; that is, to see the complete image.

[0160] When a directional backlight beam is used, the image beams penetrating the small eye boxes EB_1, EB_2, and EB_3 are closer to parallel, which makes the small eye boxes EB_1V, EB_2V, and EB_3V more elongated and larger in volume. Therefore, they can correspond to different positions of the eyes in the front and back directions, and the visible area is wider.

[0161] As shown in Figures 20A to 20C, when the first backlight Led_1, the second backlight Led_2, and the third backlight Led_3 are respectively paired with the first display block IPS_1, the second display block IPS_2, and the third display block IPS_3, the image beams are respectively focused on the respective light paths displayed by the first small eye box EB_1, the second small eye box EB_2, and the third small eye box EB_3.

[0162] As shown in Figure 20D, by superimposing the optical paths of Figures 20A to 20C, an overlapping region can be observed. In three-dimensional space, this region is a volumetric region located between the imaging concave mirror 5 and the small eyeboxes EB_1, EB_2, and EB_3, gradually shrinking in size, as shown by the small eyebox EB_123_123V in the diagonal area of ​​Figure 20E. The backlight and display block combinations shown in Figures 20A to 20C, namely IPS_1 and Led_1; IPS_2 and Led_2; IPS_3 and Led_3, when these three combinations are combined and displayed sequentially, allows the eye to see the images of IPS_1 to IPS_3 within the area of ​​the small eyebox EB_123_123V, meaning the complete image can be seen. Therefore, it can correspond to different positions of the eye in a forward direction, resulting in a wider visible area.

[0163] As shown in Figures 21A to 21C, when the third backlight Led_3, the second backlight Led_2, and the first backlight Led_1 are respectively paired with the first display block IPS_1, the second display block IPS_2, and the third display block IPS_3, the image beams are focused on the respective light paths displayed by the third small eye box EB_3, the second small eye box EB_2, and the first small eye box EB_1.

[0164] As shown in Figure 21D, by superimposing the optical paths of Figures 21A to 21C, an overlapping region can be observed. In three-dimensional space, this region is a volumetric display located behind the small eye boxes EB_1, EB_2, and EB_3, gradually shrinking in size both forward and backward, as shown by the small eye box EB_321_123V in the diagonal area of ​​Figure 21E. The combination of backlight and display blocks shown in Figures 21A to 21C ensures that the image of IPS_1 to IPS_3 can be seen within the area of ​​this small eye box EB_321_123V, meaning the complete image can be viewed. Therefore, it can accommodate different eye positions further back, resulting in a wider visible area.

[0165] As shown in Figures 17A-21E, each display block, paired with at least one backlight at a different location, can define more small eyeboxes EB_V outside the space of the eyebox array EBA on both sides of the backlight focusing surface BFP. This includes the original eyebox array EBA, forming a wider-range extended eyebox array EBA_V, which is a stereo array containing more small eyeboxes EB_V. The effective area of ​​the small eyeboxes EB_V has a Z-axis front-back depth. By switching different backlights and different display blocks, images can be projected onto small eyeboxes EB_V at different locations. Even if the eye position leaves the backlight focusing surface, different small eyeboxes EB_V can be switched to correspond to the up-down, left-right, and forward-backward movements of the eye. As long as it is within the range of the extended eyebox array EBA_V, the complete left-eye parallax image virtual image or right-eye parallax image virtual image can be seen, providing a wide-field-of-view naked-eye stereoscopic image display device. The extended eyebox array EBA_V can also use 2n+1 adjacent small eyeboxes EB_V in the left-right or up-down directions to correspond to the left or right eye, as a buffer during eye movement tracking.

[0166] As shown in Figures 22A and 22B, the aforementioned backlight module 1, main display module 31, and light-shielding module 4, together with the reflection of the imaging semi-reflective mirror 7 (windshield), can project the image onto the small eyebox EB_V in the extended eyebox array EBA_V according to the different positions of the viewer's eyes, so as to see a complete parallax image virtual image G_im without afterimage interference and without image interruption, thus achieving a high-quality naked-eye stereoscopic image display device.

[0167] As shown in Figures 23A and 23B, the wide-field-of-view extended eyebox array EBA_V includes small eyeboxes EB_V that are not only distributed on the backlight focusing surface (XY plane with Z=0), but also encompass the front and back depths along the viewer's line of sight, for example, 20cm in front and back (Z=20 ~ Z=-20). The smaller the size, the further away from the backlight focusing surface, the more the extended eyebox array EBA_V resembles a combination of two trapezoidal solid structures joined together by their lower bases, covering the range of eye movement required for a naked-eye stereoscopic image display device. The backlight of the backlight module 1 and the display area of ​​the main display module 31 corresponding to the small eyeboxes EB_V at different positions in the extended eyebox array EBA_V can be obtained through simulation or actual measurement, and this relationship can be created as a small eyebox-display area-backlight matrix table. The storage location of the backlight matrix table for the small eye box-display block-backlight can be, for example, within the control and operation module 61 or within a storage device connected to the control and operation module 61, so as to make a table lookup during actual operation.

[0168] As shown in Figure 24A, in this embodiment, the backlight module 1 has an array of 7x3 backlight sources (Led_11 ~ Led73), and the light-shielding module 4 has three switching blocks TN_1, TN_2, and TN_3 on the light-incident side of the main display module 31. The main display module 31 also has three display blocks IPS_1, IPS_2, and IPS_3, which correspond one-to-one with the switching blocks TN_1, TN_2, and TN_3. For example, as shown in Figure 24B, the distribution of the small eye boxes with Z=0 in the extended eye box array EBA_V is shown. The viewer's eyes are located on the plane with Z coordinate 0cm. The left eye corresponds to the small eye box EB_V(0,0,0), and the right eye corresponds to the small eye box EB_V(4,0,0). For example, as shown in Figure 24C, the distribution of small eyeboxes with Z=20 in the extended eyebox array EBA_V is such that the viewer's eyes are located on a plane with Z coordinate of 20cm, the left eye corresponds to the small eyebox EB_V(-2,-1,20), and the right eye corresponds to the small eyebox EB_V(2,-1,20).

[0169] Through simulation or actual measurement, a matrix table of small eye boxes, display blocks, and backlight sources can be obtained. For example, the matrix table MT of small eye boxes, display blocks, and backlight sources in the display section of Figure 25A is a matrix table of backlight sources (Led) corresponding to different display blocks (IPS) at different positions of small eye boxes (EB_V) in the X-axis direction when Y=2 and Z=0. These small eye boxes (EB_V) are close to the backlight focusing surface (XY plane with Z=0) of the extended eye box array EBA_V, and the backlight sources (Led) corresponding to the display blocks (IPS) of their small eye boxes (EB_V) are all backlight sources at the same position. For example, if the left eye is located in small eye box EB_V (4,2,0), the left eye matrix is ​​as follows:

[0170] IPS_1 to IPS_3 all correspond to Led_21. The matrix content means that when the image of IPS_1 is projected onto the small eye box EB_V(4,2,0), the corresponding switching block TN_1 and the backlight Led_21 are switched to ON; when the image of IPS_2 is projected onto the small eye box EB_V(4,2,0), the corresponding switching block TN_2 and the backlight Led_21 are switched to ON; when the image of IPS_3 is projected onto the small eye box EB_V(4,2,0), the corresponding switching block TN_3 and the backlight Led_21 are switched to ON.

[0171] Figure 25B shows another part of the small-eye box-display block-backlight matrix table MT. When Y=-2 and Z=10, it shows the matrix table of backlights (Led) corresponding to different display blocks (IPS) at different positions of the small-eye box (EB_V) along the X-axis. These small-eye boxes (EB_V) are far from the backlight focusing surface (XY plane with Z=0) of the extended eye box array EBA_V. The backlights (Led) corresponding to the display blocks (IPS) of their small-eye boxes (EB_V) may correspond to backlights at the same position, such as EB_V(0,-2,10), or to backlights at different positions. For example, if the left eye is located in small-eye box EB_V(4,-2,10), the left eye matrix is ​​as follows:

[0172] IPS_1 corresponds to Led_13, IPS_2 corresponds to Led_23, and IPS_3 corresponds to Led_33. The matrix content means that when the image of IPS_1 is projected onto the small eye box EB_V(4,-2,10), the corresponding switching block TN_1 and the backlight Led_13 are switched to ON; when the image of IPS_2 is projected onto the small eye box EB_V(4,-2,10), the corresponding switching block TN_2 and the backlight Led_23 are switched to ON; when the image of IPS_3 is projected onto the small eye box EB_V(4,-2,10), the corresponding switching block TN_3 and the backlight Led_33 are switched to ON.

[0173] The control and calculation module 61 obtains the left and right eye detection information from the eye tracking module 6, obtains the left and right eye position coordinates, and then obtains the corresponding left and right eye boxes from the left and right eye position coordinates. Then, from these eye box-display block-backlight matrix tables MT, it finds the display block-backlight matrix corresponding to the current left eye box and the display block-backlight matrix corresponding to the current right eye box, and switches the display blocks and backlight in this way, so that the viewer's left eye sees the entire left eye parallax image virtual image and the right eye sees the entire right eye parallax image virtual image, forming a naked-eye stereoscopic image.

[0174] If all switching blocks remain on, it is equivalent to removing the light-blocking module. In this case, only the small eye box-backlight matrix table is used. Each eye can correspond to one or more small eye boxes. The control and calculation module 61 obtains the left and right eye detection information from the eye tracking module 6, obtains the left and right eye position coordinates, and then obtains the corresponding left and right eye small eye boxes from the left and right eye position coordinates. Then, from these small eye box-backlight matrix tables MT, it finds the left backlight corresponding to the current left eye small eye box and the right backlight corresponding to the current right eye small eye box. In conjunction with the display module, it switches the left and right backlights so that the viewer's left eye sees the entire left eye parallax image virtual image and the right eye sees the entire right eye parallax image virtual image, forming a naked-eye stereoscopic image.

[0175] If the projection light path only contains backlight module 1 and off-axis hyperbolic mirror module 2, and no light-shielding module 4, the directional backlight can penetrate the beam intersection area of ​​the display panel and extend further in the front-back direction (similar to Figures 17E, 18E, and 19E). In addition to the eyebox area on the focal surface, the complete image can also be seen in the intersection area extending forward and backward along the Z-axis. That is, the effective area of ​​the small eyebox extends in the Z-axis direction. When the eye moves along the Z-axis, it also falls into the small eyebox area. If the projection light path includes backlight module 1, off-axis hyperbolic mirror module 2, and light-shielding module 4, more small eyeboxes can be defined in a larger area beyond all beam intersections (as shown in Figures 20E and 21E), resulting in a wider range where the complete image can be seen. In other words, when the projection light path only has the backlight module 1 and the off-axis hyperbolic lens module 2, the range of the eye box array extending forward and backward in the Z-axis direction is relatively narrow. However, when it is combined with the light-blocking module 4, the resulting extended eye box array extends forward and backward in the Z-axis direction to a wider extent.

[0176] From a timing perspective, examples of system control switching are shown in Figures 26A to 26E.

[0177] As shown in Figure 26A, assume that different display blocks for the left eye correspond to the same backlight Led_42, and different display blocks for the right eye correspond to the same backlight Led_62. In the control timing, firstly, the parallax image displayed to the left eye is switched to ON, so the image of the first display block IPS_1 is switched to ON in sequence, then the first switching block TN_1 is also switched to ON, and then the backlight Led_42 is switched to ON. At this time, the small eye box EB_V(0,0,0) corresponding to the left eye sees the image of the first display block IPS_1, and then switches to OFF in the reverse timing.

[0178] After the image of the first display block IPS_1 starts to switch to ON, the image of the second display block IPS_2 is switched to ON in sequence, the second switching block TN_2 is switched to ON, and then the backlight Led_42 is switched to ON. At this time, the small eye box EB_V(0,0,0) corresponding to the left eye sees the image of the second display block IPS_2, and then switches to OFF in the reverse sequence.

[0179] After the image of the second display block IPS_2 starts to switch to ON, the image of the third display block IPS_3 is switched to ON in sequence, the third switching block TN_3 is switched to ON, and then the backlight Led_42 is switched to ON. At this time, the small eye box EB_V(0,0,0) corresponding to the left eye sees the image of the third display block IPS_3, and then switches to OFF in the reverse sequence.

[0180] During the period when the viewer's left eye is viewing the parallax image, the corresponding switching block will only switch to ON after the display block switches to ON, and the corresponding display block will only switch to OFF after the switching block switches to OFF. Although the backlight LED_42 illuminates the entire display 3, the switching block will block the display block in transition or the display block that is not displayed, so the viewer will not see any afterimage of the display block in transition; moreover, when the parallax image is displayed to the left eye, only the backlight LED_42 corresponding to the left eye is lit, and when the parallax image is displayed to the right eye, only the backlight LED_62 corresponding to the right eye is lit, so the left eye and the right eye will not see each other's parallax image, and there is no crosstalk; controlling the backlight beam penetration time of each display block to be the same makes the brightness of the entire screen uniform.

[0181] As shown in Figure 26B, to improve the brightness of the viewed image, the time for switching the switching block in Figure 26A to ON and the time for switching the backlight to ON can be increased synchronously. This increases the time for the backlight to penetrate the display block, thus increasing brightness. In other words, changing the duration of light projection into the display block alters the image brightness. The longer the backlight penetration time, the brighter the image; conversely, the shorter the penetration time, the lower the image brightness. There is no time overlap between the switching blocks, making this suitable for situations where display blocks correspond to the same backlight or different backlights. By controlling the backlight beam penetration time to be the same for each display block, the overall brightness of the image becomes uniform.

[0182] As shown in Figure 26C, when all display blocks in the same eye correspond to the same backlight, in order to further improve the brightness of the viewed image, the time for switching blocks to turn ON can be extended. The switching block is switched ON after the display block is switched to ON, and switched OFF just before the display block is about to switch to OFF. The backlight is lit from the moment the first switching block TN_1 is switched to ON, and is only turned off when the last third switching block is switched to OFF. By controlling the backlight beam penetration time of each display block to be the same, the brightness of the entire screen is uniform.

[0183] As shown in Figure 26D, when all display blocks of the same eye correspond to different backlights, each backlight can be turned on for the entire period when the corresponding switching block is on, or for a portion of the period when the corresponding switching block is on, thereby changing the image brightness. The longer the backlight penetrates the display block, the higher the image brightness; the shorter the backlight penetrates the display block, the lower the image brightness. By controlling the backlight beam penetration time of each display block to be the same, the brightness of the entire screen is made uniform.

[0184] In this way, the problems of image retention and crosstalk in naked-eye stereoscopic image display devices can be effectively solved, making it less likely to cause dizziness for viewers and improving the quality of the viewed images.

[0185] By combining all the aforementioned technical features, the problems faced by existing naked-eye stereoscopic image display devices can be improved, eliminating image retention and crosstalk, increasing image brightness, ensuring uniform screen brightness, avoiding image flicker, and expanding the viewing area. This will make it the naked-eye stereoscopic display device that best meets the needs of mobile vehicles, such as vehicles, ships, and aircraft.

[0186] [Previous Technology] 01: Backlight 3: Display panel 5: Imaging concave mirror 6: Eye-tracking module 61: Control and operation module 7: Imaging semi-reflective mirror G_im: Image virtual image B: Directional backlight beam D: Directional image beam EB: Eye Box EBA: Eye Box Array WS: Windshield C: Superimposed mirror E_L, E_R: Eye position EB_L: Small eyelid box for left eye EB_R: Right eyelid box [This case] 1: Backlight Module 1_im: Virtual image of backlight 10, 11: Backlight array 10_im: Virtual image of backlight array 10_re: Real image of backlight array 12: Conical light cup array 13: Lens 13T: Steering Lens Array 13L: Condensing Lens Array 14: Condensing Lens 2: Off-axis hyperbolic mirror module 21: First Curved Mirror 22: Second curved mirror 221: Boundary 3: Monitor 31: Main Display Module 32: Lower polarizer 33: Liquid Crystal Layer 34: Upper polarizer 4: Light-shielding module 42: Lower polarizer 43: Liquid Crystal Layer 44: Upper polarizer 45: Reflective polarizer 5: Imaging concave mirror 6: Eye-tracking module 61: Control and operation module 7: Imaging semi-reflective mirror B: Backlight beam BFP: Backlight Focusing Surface D: Image beam EB, EB_1, EB_2, EB_3, EB_11~EB144, EB_V: small eye box EB_1V, EB_2V, EB_3V, EB_123_123V, EB_321_123V, EB_L, EB_R: small eye box EB_L, EB_R: Small eye box EBA: Eye Box Array EBA_V: Extended Eye Box Array E_L,E_L': Left eye position E_R,E_R': Right eye position G_im: Image virtual image IFP: Image Focusing Surface IPS_1, IPS_2, IPS_3: Display blocks IPS_1_im, IPS_2_im, IPS_3_im: Virtual images Led_1, Led_2, Led_3, Led_11~Led144: Backlight Led_L, Led_R: Backlight MC: Center of the mirror MT: Mini-Eye Box - Display Block - Backlight Matrix Table OA: Optical Axis OCA: Optical Adhesive pix_p: pixel pix_t: pixels TN_1, TN_2, TN_3: Switching blocks

Claims

1. A naked-eye stereoscopic image display device with image-zone backlighting, suitable for use with an imaging semi-reflective mirror, comprising: a backlight module including a backlight array composed of a plurality of backlights emitting a directional backlight beam; a display including a main display module and a light-shielding module superimposed on each other, the main display module alternately displaying a left-eye parallax image and a right-eye parallax image, the directional backlight beam passing through the display to form an image beam; and an imaging concave mirror reflecting the image beam; wherein, The main display module defines a plurality of display blocks, and the light-shielding module defines a plurality of switching blocks. Each switching block corresponds to one display block. When the main display module displays an image, at least one switching block is switched in a time-division manner to control the display block to project the image beam in a time-division manner. The remaining switching blocks block the display blocks in the main display module that are still in the switching state or have not yet been switched. The equivalent distance between the backlight array and the imaging concave mirror is greater than the focal length of the imaging concave mirror. The directional backlight beam is reflected by the imaging concave mirror and the imaging semi-reflective mirror, and then projected and converged on a backlight focusing surface to form a real image of the backlight array. Each backlight forms an independent small eyebox, and all the small eyeboxes constitute the real image of the backlight array, defining an eyebox array.

2. The naked-eye stereoscopic image display device with image partition backlight as described in claim 1, wherein the equivalent distance between the main display module and the imaging concave mirror is less than the focal length of the imaging concave mirror, and the left-eye parallax image and the right-eye parallax image respectively form a left-eye parallax image virtual image and a right-eye parallax image virtual image on the side of the imaging semi-reflective mirror away from the eye box array.

3. The naked-eye stereoscopic image display device with image partition backlight as described in claim 1, wherein the effective area of ​​each of the small eye boxes extends on both sides of the backlight focusing surface, and the small eye boxes gradually shrink in the front-back direction along the backlight focusing surface.

4. The image partition backlight naked-eye stereoscopic image display device as described in claim 1, wherein when the main display module displays a left-eye parallax image or a right-eye parallax image, at least one of the switching blocks is switched to the display block that projects one of the eye parallax images, and the remaining switching blocks block the display block that displays the other eye parallax image.

5. The naked-view stereoscopic image display device with image partition backlight as described in claim 1, wherein the liquid crystal switching speed of the main display module is slower than the liquid crystal switching speed of the light-shielding module.

6. The image partition backlight naked-view stereoscopic image display device as described in claim 1, wherein the light-shielding module is superimposed on one light-incident side of the main display module.

7. The image-zone backlight naked-view stereoscopic image display device as described in claim 1, wherein an optical adhesive is provided between the main display module and the light-shielding module, and no polarizer is provided between the optical adhesive and a liquid crystal layer of the main display module.

8. The image partition backlight naked-view stereoscopic image display device as described in claim 1, wherein an optical adhesive is provided between the main display module and the light-shielding module, and no polarizer is provided between the optical adhesive and a liquid crystal layer of the light-shielding module.

9. The naked-view stereoscopic image display device with image partition backlight as described in claim 1, wherein the imaging semi-reflective mirror is a windshield or a superimposed mirror.

10. The naked-view stereoscopic image display device with image partition backlight as described in claim 1, wherein the duration of the switching block being turned on or the duration of the backlight being turned on is controlled to correspond to a preset brightness.

11. The naked-eye stereoscopic image display device with image partition backlight as described in claim 1, wherein at least one of the display blocks is equipped with a plurality of different backlights to project the image beam, and a plurality of small eyeboxes are defined outside the eyebox array space on both sides in the front-back direction of the backlight focusing front, and the additionally defined small eyeboxes together with the eyebox array form an extended eyebox array.

12. A naked-eye stereoscopic image display device with image partition backlight as described in claim 1 or 11, further comprising an eye-tracking module for detecting the relative position information of the left and right eyes and the eye-tracking module; and a control and calculation module connected to the backlight module, the display, and the eye-tracking module for obtaining the detection information of the eye-tracking module, determining a left eye position and a right eye position, and determining a left-eye small eye box and a right-eye small eye box based on the left eye position, the right eye position, and the eye box array or the extended eye box array, and obtaining a corresponding left-eye matrix and a right-eye matrix based on a small eye box-display block-backlight matrix table; the left-eye matrix and the right-eye matrix include their corresponding display block, switching block, and backlight, the display block, the switching block, and the backlight are controlled to project the image beam of the left-eye parallax image to the left eye position and the image beam of the right-eye parallax image to the right eye position, respectively.

13. The image partition backlight naked-eye stereoscopic image display device as described in claim 11, wherein switching different small eyeboxes in the eyebox array or the extended eyebox array corresponds to an eye displacement amount, the eye displacement amount including displacement in a two-dimensional direction or a three-dimensional direction.

14. The naked-eye stereoscopic image display device with image partition backlight as described in claim 12, wherein the eye box array or the extended eye box array defines 2n+1 adjacent small eye boxes corresponding to the left eye position or the right eye position, where n>0 and n is a positive integer, a central small eye box of the plurality of small eye boxes is aligned with the pupil of one eye, and the other 2n small eye boxes are distributed on the upper and lower sides or the left and right sides of the central small eye box.

15. The image-zone backlit naked-eye stereoscopic image display device as described in claim 12, wherein the switching interval time for each display block of the main display module to project the image beam to the same eye position is less than 41.67 ms.

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