KR20140111553A - Stereoscopic display apparatus, and display method thereof - Google Patents

Abstract

Disclosed is a stereoscopic display apparatus. Disclosed is the stereoscopic display apparatus. The stereoscopic display apparatus includes an image panel which displays an image through a vertical sub perspective, a panel control part which controls the position of the displayed image, a backlight unit which provides light to an image panel through an eye/head tracking, a backlight control part which controls the backlight unit, an eye tracking sensor which detects the eye position of a viewer and provides corresponding eye position data, and a parallax part which includes a parallax element designed to selectively show the vertical sub perspectives having a predetermined first gap. The panel control part and the backlight control part receive the eye position data from an eye tracking sensor and control the image panel and the backlight unit based on the received eye position data.

Description

[0001] Stereoscopic display apparatus and display method [0002]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a stereoscopic display apparatus and a display method thereof, and more particularly, to a stereoscopic display apparatus employing a stereoscopic display system and a display method thereof.

Various types of electronic devices are being developed and distributed due to the development of electronic technologies. In particular, display devices such as TV, one of the household appliances most commonly used in general households, have been rapidly developing in recent years.

As the performance of the display device has become higher, the kinds of contents displayed on the display device have also been variously increased. Particularly, a stereoscopic display system capable of viewing 3D contents has been developed and spreading.

The stereoscopic display system can be roughly classified into a non-eye-tightening system that can be largely watched without glasses, and a spectacular-type system that must be watched with glasses. Although the non-eye-tightening system has the advantage that it can view 3D images without glasses, the image quality deteriorates, and the stereoscopic effect varies depending on the viewer's position.

The conventional non-eyeglass stereoscopic display selectively displays left and right view images or scenes in the left and right of a viewer. The left eye image and the right eye image are displayed on the same flat screen, but they can be selectively displayed by the left eye and right eye due to the special design of the display. The corresponding perspective image can only be seen when the viewer's head and eyes are located at a particular location coinciding with what is called a " viewing zone " or a " viewing window ". Objects located at different depths are displayed with different time differences at each time point. In the glassesless display, the viewer recognizes the object in three dimensions with binocular parallax. In order to provide viewer freedom, the spectacles stereoscopic display can provide a viewing window according to the position of the viewer ' s eyes when the viewer changes his head and body position. These kinds of displays are " head / eye tracking stereoscopic display ". In general, a spectacles stereoscopic display can be provided to provide the viewer with a number of viewing windows that can smoothly move from one pair of windows to another without loss of stereoscopic effect. These autostereoscopic displays are called multi-view displays. This method requires displaying a larger capacity of data as the viewpoint increases because each window has to display images at different viewpoints. This is the reason why most multi-view displays have less than 10 viewpoints.

Although different objects in one scene are recognized as different depths due to binocular parallax in the non-eyeglass stereoscopic display, the visual system of the viewer is not completely satisfied with the non-stereoscopic stereoscopic method of displaying 3D images. This problem is that the focus adjustment mechanism of the eye has a tendency to focus on the actual display screen on which the image is displayed instead of the position where the depth is perceived. This is caused by the image projected onto the retina of the eye, which is most pronounced when the eye focuses on the screen. This situation is called a "convergence-accommodation conflict". It causes eye strain, eye fatigue, and other dysfunctions, thus reducing the comfort of the viewer.

To provide an accurate focal position, a second refocus technique may be applied. The second multi-view display is a multi-view display with a very small sized viewing window. It is important that one window size should be smaller than 2.5 mm, half of the pupil diameter (5 mm), so that two or more views are simultaneously visible to the viewer. The second multi-view display should be able to provide focus control of the eye. However, if the window size is 2.5mm and the number of scenes is limited to 10, the viewer's freedom will be limited to only 2.5mm. In order to expand the viewer's freedom, the secondary display must display more than ten views. In current flat panel type autostereoscopic displays this is not possible.

 In stereo hologram technology, a technique for providing another eye focus adjustment is applied. The content of a digital hologram in a stereo hologram is not sufficiently small in pixel size and has a limited resolution to provide a large viewing window. Stereo hologram technology uses accurate eye tracking to provide viewers with enough viewing freedom. A disadvantage of stereo hologram technology is that it is based on diffraction and interference of light. Since it has different diffraction angles for each wavelength, it requires a coherent light source such as a laser.

Another disadvantage is that at least two of the graphic data bits known as " pixels " are required to produce a single holographic data bit known as a " fringe ".

1 is a view for explaining a conventional technique.

1, the display includes an LCD panel 11, an electrically controllable light source (not shown) controlled along a head / eye tracking system having a camera 15 for sensing a viewer's head / And a directional backlight 12 composed of a focusing lens 14 (for example, a CRT TV screen) and a focusing lens 13. The left and right perspectives are successively reproduced in the image panel. Synchronized with the left and right images, the light source creates a bright spot at that location, only the left and right eyes receive the light and can see the image displayed on the panel.

During the period when the left eye view image is displayed on the image panel, the eye tracking system senses the 2D position of the viewer ' s eyes and sends a signal corresponding to the left eye image to the light source. In response, the light source creates a light emitting point 14a at a position corresponding to the left eye. The light emitted from the light emitting point passes through the lens 13, passes through the LCD panel in which the left eye image is reproduced, and focuses on the left eye of the viewer. For the viewer's right eye, the image panel appears as a dark panel with no image. During the time the right eye view is displayed on the image panel, the eye tracking system senses the 2D position of the viewer's eye and sends a signal corresponding to the right eye image to the light source. In response, the light source generates the light emitting point 14b at the position corresponding to the right eye. The light emitted from the light emitting point passes through the lens 13, passes through the LCD panel in which the right eye image is reproduced, and focuses on the left eye of the viewer. For the viewer's left eye, the image panel appears as a dark panel without any image. The left and right eye images are sequentially displayed on the panel, each of which has a frame rate equal to or higher than 50 Hz (e.g., 100 Hz or higher panel frame rate). Due to the inertia of the human visual system, viewers perceive that the left and right images are displayed simultaneously and feel a cubic sensation.

Different objects in the scene are recognized at different depths because of stereopsis. In contrast, the eye focus adjustment mechanism tends to adjust the eyeball on the LCD screen instead of the perceived depth dominated by stereopsis. This occurs because, in a stereoscopic display, and in a conventional non-eyeglass stereoscopic display, the image projected onto the retina of the eye appears most clearly when the eye focuses on the screen. This situation is called a "convergence-accommodation conflict". This causes eye strain, eye fatigue, and other dysfunctions, thus reducing the comfort of the viewer.

It is an object of the present invention to provide a stereoscopic display apparatus and a display method thereof for displaying sub-perspectives in a vertical direction.

According to an aspect of the present invention, there is provided a stereoscopic display apparatus including an image panel for displaying an image through an interleaved vertical sub perspective set, A backlight unit having an output pupil controllable in at least a first main horizontal direction and providing light through eye / head tracking, a backlight unit controlling the backlight unit, An eye tracking sensor for detecting the eye position of the viewer and providing corresponding eye position data; and a second main horizontally arranged paradigm, designed to selectively display sub- And a parallax portion including a parallax element, Fisherman and the backlight control unit receiving the eye position data from the eye tracking sensor, and based on the received eye position data, and controlling the image panel and the backlight unit, the first gap is smaller than the diameter of the eye pupil.

Here, the parallax portion may include at least one of a lenticular lens array and a parallax barrier.

In addition, the backlight unit may include a one-dimensional optical source array, collimation optics, and a directional diffuser.

In this case, the collimation optical system may include a wedge type light guide plate having a curved thick end combined with a prism sheet and a Fresnel lens.

In addition, the parallax portion may be switched between an active state to provide eye-accommodation and an inactive state to provide a 3D stereoscopic image with a higher vertical resolution or to provide a 2D image.

In addition, the parallax section may comprise a lenticular lens array comprised of an optically anisotropic material, having a polarization switch for switching the lenticular lens between an active state and an inactive state.

In addition, the parallax portion may include a parallax barrier, which is composed of an optical LCD panel switchable between a barrier mode and a transparent mode.

In addition, the image panel and the backlight unit may perform a field-sequential-color operation.

Meanwhile, the stereoscopic image display method according to an embodiment of the present invention includes a step of selectively displaying left and right images on left and right eyes of a viewer to display a stereoscopic image, wherein the left and right images are selectively displayed in a space At least two sub-perspectives are close enough to be simultaneously recognized by the viewer ' s eyeball, a combination of low parallax sub-perspectives.

Here, the left and right sub-perspective sets may be sequentially displayed.

In addition, the left and right sub-perspective sets may be displayed in parallel.

In addition, the low parasitic sub-perspective set may include a sub-perspective in which exit pupils are distributed along a vertical line.

Also, the low parallax sub-perspective set may include a sub-perspective in which the exit pupils are distributed along a line that is inclined between +45 degrees and -45 degrees in the horizontal direction.

The set of low parasitic sub-perspectives may also include a sub-perspective in which the exit pupils are distributed along a line that is inclined between +45 degrees and -45 degrees in the horizontal or horizontal direction.

In addition, the motion of the viewer in the horizontal direction may be provided based on eye / head tracking, or may be provided based on the directional display of two sets of sub-aspects by the eye / head tracking.

Further, the motion of the viewer in the horizontal direction may be provided based on the display state of the left and right sub-perspective sets having vertical polarization and the use of the polarizing glass by the viewer.

Further, the motion of the viewer in the horizontal direction can be provided based on the display state of the left and right sub-perspective sets in different spectral regions and the use of spectrum spectacles by the viewer.

In addition, the motion of the viewer in the horizontal direction may be provided based on the display state of the left and right sub-perspective sets in the time-sequential manner and the use of the shutter glass by the viewer.

In addition, the motion of the viewer in the horizontal direction may be provided based on the display of a plurality of horizontal sub-perspective sets.

The viewer's movement in the vertical direction may also be provided based on displaying a sub-perspective on the main lobe of the directional display and simultaneously displaying the clusters of the sub-perspective on the upper and lower lobes of the directional display.

A method of capturing a 3D image according to an exemplary embodiment of the present invention includes capturing a perspective view using a camera at positions dispersed in a first horizontal direction (x direction) and a second vertical direction (y direction) Wherein at least two positions in the first direction have a parallax gap defined by the interocular space and at least two positions in the second direction have a parallax interval defined by the pupil diameter of the eye.

According to another aspect of the present invention, there is provided a stereoscopic display apparatus including an image panel for displaying an image through a vertical sub perspective, a panel controller for adjusting the position of the displayed image, an eye / ) A backlight unit for controlling the backlight unit, an eye tracking sensor for detecting the eye position of the viewer and providing corresponding eye position data, Wherein the panel control and the backlight control are configured to receive the eye position data from the eye tracking sensor and to receive the eye position data from the received eye position < RTI ID = 0.0 > Based on the data, Controlling the bit unit, and the first distance may be smaller than the diameter of the eye pupil.

As described above, according to the present invention, it is possible to provide a high resolution 3D image in a state in which the motion of the viewer is free.

1 is a view for explaining a conventional technique.
2A and 2B are views illustrating a structure of a stereoscopic display device according to an embodiment of the present invention.
3 is a view for explaining the operation of the vertical plane of the stereoscopic display apparatus according to the embodiment of the present invention.
4 is a diagram for explaining a method of displaying contents.
5A is a view for explaining a mapping state of perspective images for horizontal alignment of a lenticular lens.
FIG. 5B is a view for explaining a mapping state of perspective images for the tilted alignment of the lenticular lens. FIG.
6 is a diagram for explaining a method for providing vertical eye / head tracking.
7 is a view for explaining the structure and operation of the backlight unit.
8 is a view for explaining a display structure having a slim backlight unit.
9 is a view for explaining a structure of a changeable lenticular lens having an anisotropic optical material and a polarization switch.
10 is a diagram for explaining a video capturing method.
11A and 11B are views for explaining a stereoscopic display according to the related art.
11C and 11D are views for explaining a stereoscopic display according to an embodiment of the present invention.
12A and 12B are views for explaining various embodiments of the mutual arrangement of the lens, the diffuser, the LCD panel, and the parallax barrier.

Hereinafter, the present invention will be described in detail with reference to the accompanying drawings.

2A and 2B are views showing the structure of a stereoscopic display device according to an embodiment of the present invention.

Specifically, FIG. 2A shows a horizontal sectional view and FIG. 2B shows a vertical sectional view.

The stereoscopic display device of FIGS. 2A and 2B may be implemented by various types of display devices such as a TV, a monitor, a mobile phone, a PDA, a PC, a set-top PC, a tablet PC, an electronic photo frame, a kiosk, In addition, the stereoscopic display apparatuses of FIGS. 2A and 2B can be implemented as an apparatus for performing stereoscopic display in a non-eyeglass system, but the present invention is not limited thereto.

2A and 2B, the stereoscopic display apparatus includes a backlight unit 21, an image panel 22, a parallax unit 23, an eye tracking sensor 24, a backlight control unit (or backlight control unit) 29, And a panel control unit 30.

The backlight unit 21 provides light in the direction of the image panel 22. The backlight unit 21 is divided into a direct type and an edge type depending on where the light emitting device is located. In the direct type, the light emitting elements are uniformly arranged on the back side of the image panel 22, and the light emitting elements emit light directly to the image panel 22. [ On the other hand, in the edge type, the light emitting device is disposed at the edge of the image panel 22, and the light is reflected toward the image panel 22 using the light guide plate.

In addition, the backlight unit 21 may be a color sequential backlight unit applied to a general backlight unit or Field Sequential Color (FSC) LCD display that is typically applied to an LCD panel. That is, the type of the backlight unit 21 may vary depending on the type of the image panel 22.

In particular, the backlight unit 21 may be embodied as a directional backlight capable of controlling a pupil at least in the horizontal direction.

Specifically, the backlight unit 21 has an output pupil controllable in at least a first main horizontal direction, and provides a time-sequential stereoscopic display and eye / head tracking.

The image panel 22 displays the image through a set of vertical sub-perspectives in interleaved form.

Specifically, it includes a plurality of pixels arranged in a plurality of rows and columns. The image panel 22 may be implemented as an LCD panel, and each pixel may be implemented as a liquid crystal cell. When light generated in the backlight unit 21 is incident on each pixel of the image panel 22, the image panel 22 displays an image by adjusting the transmittance of the light incident on each pixel according to the image signal. Specifically, the image panel 22 includes a liquid crystal layer and two electrodes formed on both surfaces of the liquid crystal layer. When a voltage is applied to the two electrodes, an electric field is generated to move molecules of the liquid crystal layer between the two electrodes to control the transmittance of light. The image panel 22 divides each pixel by column, and drives each pixel column so that an image at a different view point can be displayed for each column.

The image panel 22 may be a general panel having a color filter or a panel operating in a field sequential color (FSC) driving manner. The field sequential color driving method may alternatively be called a field sequential method or a color sequential driving method. The field sequential color driving method is a method of sequentially projecting R, G, and B light in a temporal manner without using a color filter.

The parallax portion 23 is disposed on the front surface of the image panel 22 to disperse the light emitted from the image panel 22 for each viewing area. Thus, light corresponding to an image at a different view point is emitted for each viewing area. The parallax section 23 may be implemented as a parallax barrier or a lenticular lens array. The parallax barrier is implemented as a transparent slit array including a plurality of barrier regions. Thus, light is blocked through a slit between the barrier regions so that image light at different viewpoints is emitted for each viewing area. The width and pitch of the slit can be designed differently depending on the number of viewing images included in the multi-view image and the viewing distance. The lenticular lens array includes a plurality of lens regions. Each lens region is formed to have a size corresponding to at least one pixel column, and the light transmitted through the pixels of each pixel column is dispersed differently for each viewing area. Each lens region may include a circular lens. The pitch and radius of curvature of each lens can be designed differently depending on the number of viewpoint images and viewing distance.

The parallax portion 23 includes a second main horizontally arranged parallax element, which is designed to selectively show sub-perspectives having a predetermined first spacing in space.

Particularly, the paraxlax portion 23 can be realized in the form of being active in the vertical direction, that is, extending in the horizontal direction. For example, the lens sheet is arranged so as to provide two or more viewing zones in the viewer ' s eye pupil, and a position sensor, i.e., an eye tracking sensor 24, may be provided.

On the other hand, the backlight unit 21 includes at least one viewing window, known as an exit pupil or viewing zone, which is located in a space that provides the same brightness and controllability to the image panel 22, It is important to make. 2A and 2B, the structure of the backlight unit 21 includes a light source array 25 (e.g., LED), a lens 26, a diffuser 27, a backlight control unit (or LED control unit) 29, . The backlight unit 21 is arranged to provide a viewing zone at a certain viewing angle, and the image panel 22 is controlled by the panel control unit 30. [

In particular, the panel control unit 30 can adjust the vertical position of the image displayed on the image panel 22. [

If one of the LEDs, e. G. LED 25a, is turned on, the emitted light is focused behind the lenses at distance L2 distance, which is defined as: <

Where distance L1 is the distance from the LED to the lenses, and F is the focal length of the lenses.

The shape of the focused point 28 may extend in the vertical direction according to the directional diffuser 27. The horizontal size is determined by the geometry of the LED light emitting surface and the viewing zone formation spreader 27. The horizontal size may be the LED average eye distance (inter-ocular) or a smaller value. The vertical size should be chosen to provide the viewer with the desired vertical freedom. The focused point 28 functions as a viewing zone of the directional display. The main feature of the viewing window is that all rays coming out of the lens reach the viewing window and there are no rays at the other intersection points. If the viewer's eyes are located within the viewing window, the viewer sees that the surface of the diffuser 27 shines brightly.

In contrast, when the viewer's eyes are positioned on the side of the viewing window, the viewer sees that the surface of the diffuser is not brighter. If a transmissive image panel displays an image, the image is only visible in the eye within the active viewing zone. In effect, multiple LEDs can be turned on instead of a single LED to create a wide viewing window for a viewer's eye. The viewing window size is set to be smaller than the interocular distance, which is usually about 65 mm in average value, so viewers can not see the image of the panel with both eyes at the same time. The horizontal position of the viewing zone is defined by the position of the active LED in the array.

Another viewing zone located on the left side (lower side in FIG. 2A) or on the right side (upper side in FIG. 2A) can be made from the first viewing zone by turning on another LED, for example LED 25b, from the light source array 25. Other rays emerging from another LED 25b and the corresponding viewing window are shown in dashed lines in Fig. 2a. The separation between the new viewing zones in the previous viewing zone is defined by the pitch of the LED array and the optical power of the lenses m = L2 / L1. The pitch of the light source array can be selected to provide left and right viewing zones to the left and right eyes of the viewer, which can be turned into an active state by turning on different light sources.

The backlight control unit 29 can drive the LED in response to the eye position signal generated by the eye tracking sensor 24 according to a predetermined algorithm.

The display structure in the vertical crossing section is shown in Fig. 2B. The display output in the vertical intersection section is generally defined as the characteristics of the lens 26, the directional diffuser 27, the mutual arrangement of the image panel 22, the lens sheet 23 and their mutual arrangement. In one embodiment, the LCD pixels are divided into M groups each having N columns.

The lens sheet 23 includes at least M cylindrical lenses 24 extending in the horizontal direction. The columns in each group can be numbered 1, 2, and N. The number increases in column vertical coordinates. For example, in FIG. 3, each group has six columns.

Each lens of the lens sheet 23 produces an enlarged image of the columns of LCD pixels at a predetermined viewing distance. These images are numbered in the same way on the right side of FIG. The lenticular pitch is set smaller than (N x pixel pitch) so as to provide matching of all the column images with the same number as shown on the right side of Fig. The image of each column functions as a viewing sub-window. These images of columns 1 through N make the viewing window 28 structure as shown in FIG. 2B, 28-1. If the vertical angle of the diagram of the directional diffuser is greater than the N viewing window, the viewing windows are repeated as shown in Fig. 2B, 28-1 and Fig.

In contrast to conventional multi-view displays, the display according to the present invention provides viewing windows with a microstructure in the vertical direction. The pitch of the viewing zone structure Pv must be smaller than the viewer's pupil, so that perspective images displayed in two or more viewing subzones are simultaneously displayed on the retina of the eye. The pupil of the eyeball is shown by the oval dotted line on the right side in Fig. Its size can be seen twice as big as the viewing subzone size. This can be expressed as:

Here, the distance L3 is the distance from the lens to the viewer's eyeball, L2 is the distance from the lens to the image panel, D is the pupil diameter (D ... 5 mm), and P is the pixel pitch.

The LCD control unit 30 can adjust the vertical position of the displayed image according to the head / eye position detected by the head / eye tracking system. In this case, tracking should be provided to keep the correct order of sub-perspective viewing zones in the pupil of the eye.

Since the sub-perspective set of viewing zones is repeated or replicated in the vertical direction as shown in Fig. 4, there is a relative eye position (see Fig. 4) that receives sub-perspectives in which the ocular pupils are placed in reverse order do. By virtue of the vertical tracking, the viewing zone system is positioned in the vertical direction, and the pupil of the eye never appears in this wrong position. The tracking method is shown in Fig.

The displayed content, i.e., the format of the graphic content displayed on the image panel, is the left and right eye perspective of the object or scene displayed in sequential frame order. Each perspective consists of N vertical sub-perspectives. By way of example, these perspectives and sub-perspectives may be photographed by a camera or video camera, as shown in FIG. 4, the right sub-perspectives 44 of the object 41 are taken by the camera 42 sequentially at slightly different positions N along the Y axis (in the vertical direction) shown by the dotted line. The left sub-perspectives 45 of the object 41 are photographed by the camera 43 sequentially at slightly different positions N. [

In general, the vertical arrangement of the N cameras can be applied to capture all sub-perspectives at the same instant. The input graphic data applied to the image panel is composed of an odd frame sequence composed of right eye sub-perspectives, and even frames composed of left eye sub-perspectives.

The frames are composed of N sub-perspective images of interleaved form so that the viewing zone of each sub-perspective appears at slightly different positions in the vertical direction when a horizontal lens is applied. An example of the interleaved configuration of sub-perspectives is shown in Fig. 5, where different pixel columns belong to different sub-perspectives. Pixel groups belonging to the same perspective are shown with the same hatching.

The dotted lines show the relative positions of the lenticular lenses aligned in the column direction. In some embodiments, the lenticular lenses may be aligned in the column direction at a slightly inclined angle &thetas; to share a resolution reduction between vertical and horizontal directions. Perspective images should be rendered in different ways in this case. A group of pixels representing all four displayed views is shown in Figure 4B.

The different perspectives needed to display the positions of different viewers can be stored in the memory of the graphic data source and retrieved according to the current output data of the eye tracking system. In general, graphic data can be computed in real time using one of the already known algorithms of intermediate view generation. A combination of stored and calculated data may also be applied.

The operation of the display according to the present invention can be described based on Figs. 2A, 2B, 3 and 4.

The eye tracking sensor 24 senses the two-dimensional position of the viewer's eyes and transmits a corresponding signal to the backlight control unit 29 and the panel control unit 30, while the left eye sub-perspective is displayed on the image panel 22. [ In response, the backlight control unit 29 turns on some LEDs selected in the LED array conforming to a preset algorithm. The backlight control unit 29 turns ON only the LEDs, for example, 26a, which can not reach the viewer's left eye at the current position and provide the most comfortable viewing time for the right eye. In FIG. 2A, only the LED 26a is shown as being turned ON for clarity, but substantially several LEDs can be turned ON.

The panel control unit 30 receives the eye position data in the vertical direction and adjusts the vertical position of the displayed image so that the upper and lower ranges of the viewing zone are symmetrically positioned with respect to the viewer ' do. Reaches the lens and image panel emitted from the LED.

The lenses transform the diverged bundle of light into a converged bundle of light to focus near the right eye position, and the viewer sees multiple right vertical sub-perspectives displayed on the panel at the same time. At that moment, the right eye will not see the displayed image, because the directional backlight will not send any rays in that direction. Since multiple sub-perspectives are simultaneously recognized by the left eye, the image point can be blurred, but if the eye is adjusted to the displayed depth, the blurred image can be focused.

During the period that the left eye sub perspective is being displayed on the image panel, the backlight control unit 29 turns on another group of LEDs simplified by one LED 25b in Fig. 2A. The LED 25b together with the lens 26 and diffuser 27 produces a bundle of light focused near the viewer's right eye position. The right eye of the viewer simultaneously recognizes the right sub-perspectives displayed on the image panel while the left eye does not see any image on the panel. Since several sub-perspectives are simultaneously recognized by the right eye, the image point may appear blurry, but if the eye is adjusted to the depth of the displayed point, the blurred image may be focused.

Left and right perspectives are sequentially displayed on panels higher than 60 (50) Hz, with frame rates equal to or higher than 60 (50) Hz for each (frame rate of 120 (100) Hz or higher). Because of the inertia of the human visual system, the viewer simultaneously perceives the left and right images as being displayed and feels stereoscopic. Because the perceived stereoscopic sensation is provided with an accurate regulatory response, the viewer feels increased visual comfort as he sees the actual stereoscopic image.

If the viewer changes his head position in the horizontal direction, the head tracking system detects a new position and sends a signal to the backlight control 29 to turn on another LED group to compensate for the motion. If the viewer changes his head position in the vertical direction, the head tracking sensor detects the new position and sends a signal to the LCD controller 30 to adjust the vertical position of the displayed frame to compensate for this movement.

The stereoscopic display according to the present invention is capable of eyeballing, and at the same time provides free motion of the viewer in both vertical and horizontal directions. Accordingly, it is not necessary to display a large number of views in order to simultaneously provide viewer freedom and eyeball control.

The parallax barrier provides a higher optical loss, although a parallax barrier may be applied as an alternative to the lenticular lens 23. A Fresnel lens may be applied instead of the lens 26. [ Figs. 12A and 12B show the mutually arranged state of the LCD panel 22, the parallax barrier 61, the Fresnel lens 62, and the diffuser 27. Fig. Showing mutually adjustable deformations.

On the other hand, it is desirable to make the display as slim as possible. The structure and operation of the slim backlight unit 21 are shown in Fig. 7, in which the LED array 51, the light guide plate 52, the prism sheet 53, A Fresnel lens 54, and a diffuser 55 are shown.

In the slim backlight unit 21, the light emitted by the LED travels inside the wedge-shaped light guide plate 52 and is bent at an end thereof and provided as horizontal reflection grooves. Light reflected by the curved end of the light bundle is directed to the surface by the grooves. Due to the curved end of the light guide plate 52, the light bundle is parallel, but is inclined from the light guide plate 52 to the surface at some large angle. The prism sheet 53 corrects the direction of the light beam in the vertical direction. The Fresnel lens 54 collects parallel light beams at the viewing distance and the diffuser 55 expands the viewing zone in the vertical direction.

A conceptual view of the entire display having the slim backlight unit 21 is shown in Figs. 8A and 8B. The operation of a display having a slim backlight is the same as that of a display having a conventional directional backlight unit.

On the other hand, in order to switch between the 2D and 3D modes, the lenticular lens can be made changeable. For example, the changeable lenticular lens sheet may include a combination of a polarization switch and at least one, two-layer lenticular optical element made of a birefringent material as shown in Fig. 9, the lenticular layer 71 is made of anisotropic material, the layer 72 is made of an isotropic material, and the layer 73 is a polarization switch including, for example, LCC (Liquid Crystal Cell). The refractive index of an isotropic material is equal to the general refractive index or rare refractive index of anisotropic material. The range of the two materials is in the form of a horizontal lenticular arrangement. This complex lenticular optical element exhibits the characteristics of a lenticular lens for indirect light with a first polarization (e.g., horizontally) and operates as a plane-parallel plate for indirect light with a second polarization (e.g., vertically) . The polarization switch changes the polarization of the indirect light when the drive voltage from the control section 74 is not applied and is not changed without applied voltage. For example, the indirect light (from the LCD panel) is polarized in the vertical direction as shown in Fig. In general, if the polarization is not changed, the optical element is capable of 2D imaging without affecting the propagation of light. This is provided when the driving voltage is applied. In addition, to provide a wide viewing zone, all LEDs must be on. When the driving voltage is not applied, the polarizing switch 73 horizontally changes the optical polarization and the optical element shows the characteristics of the lenticular lens, thus enabling 3D stereoscopic imaging with eye coordination. This provides a 2D-3D mode change.

Another object of the present invention is a method for capturing a 3D image of an object or a scene. Conventionally, the simplest way to capture a 3D image is to capture two or more perspective views. Perspective views are taken at different positions in the camera with 2D images of the object. For the stereoscopic display, two scenes (views) taken at a specific time difference in the horizontal direction were sufficient. Two or more perspective views must be taken to provide a motion parallax display. In general, two views photographed with horizontal parallax are used to create a depth map of the scene, and additional views are reconstructed using the depth map and at least one view. Conventional methods of image capture for super-multi-view display include reconstruction and capturing of a large number of views photographed at small distances in the horizontal direction.

The method according to one embodiment of the present invention is conceptually illustrated in FIG. In Fig. 10, the positions of the camera lenses distributed along the x and y axes and the object characterized by the depth in the z direction are shown. This method has a horizontal direction (x direction) and a vertical direction (vertical direction) including at least two positions in a vertical direction (y direction) separated by at least two positions in the horizontal direction (x direction) (or cameras) at a number of locations scattered in a direction (y direction).

Figure 10 shows the locations of the camera lenses as circles of bold and dotted lines. Many locations in the vertical direction are usually ... 10 (only five positions are shown in Fig. 10). In some cases, the intermediate views photographed from the positions shown by the dashed lines can be inserted between images photographed at the desired positions shown in bold line. More horizontal positions and corresponding views can be provided if horizontal head tracking is possible so that the display provides motion parallax. The images photographed in the described manner can be applied to a stereoscopic display having the eyeball regulating method disclosed herein.

Another object of the present invention is a method of displaying stereoscopic images. Conventionally, images could be three-dimensionally displayed by head / eye tracking in a time-sequential manner requiring immediate display of one perspective as shown in FIG. This conventional method requires a lower data amount and can be performed without a reduction in image resolution using a single image panel. The disadvantage of this method is that it does not provide accurate eye coordination. Another conventional method is the ultra multi-point method as shown in FIG. 11B. This method requires displaying many perspective views with high spatial density of viewing windows. This method can not be implemented using conventional flat panel technology.

The method according to an embodiment of the present invention selectively presents a left-right perspective to the left and right eyes of a viewer as shown in 11c. In this case, the left and right perspectives include a combination of several low parallax vertical sub-perspectives, which are selectively displayed in each of the viewing windows but are too close together so that one or more sub-perspectives are perceived simultaneously by the viewer's eyes.

The actual alignment may be along a generally vertical (horizontal) direction, including inclining at an angle of less than plus or minus 45 degrees in the vertical (horizontal) direction. This may be satisfied if the viewing windows of each sub-perspective are smaller than the viewer's pupil of the viewer. Perspectives are displayed such that the viewing window follows the eye / head movement of the viewer, for example, by the eye / head tracking system, to provide a range of possible viewer positions. To simplify the requirements for tracking accuracy, the number of vertical perspectives displayed is large enough to cover 2-3 pupil diameters. Since at least two scenes must be recognized at the same time, the minimum number of vertical sub-perspectives displayed is 4 ... 6. Thus, the eye / head position can be slightly changed without loosing the viewing windows even when tracking is off. On the other hand, the vertical position of the displayed content can be adjusted according to the viewer's eye / head position in order to prevent the sub-perspective from being recognized in the wrong order.

In some embodiments, the viewing windows of vertical sub-perspectives are made with the help of a horizontal lenticular or a parallax barrier. Conventionally, instead of forming a single set of vertical sub-perspective windows, a lenticular or parallax barrier forms the main lobe window system and main lobes located higher and lower than the main lobe. Herein, these are referred to as an upper lobe and a lower lobe. In Figure 11, the main lobe and its clones are separated into horizontal lines. If the viewer ' s pupil is located in the range between the lobes, the perceived vertical sub-perspectives may appear in the reverse order. The reverse order of perspectives does not provide accurate eye coordination. The vertical eye / head tracking system should prevent opposite order perspectives from hitting the viewer ' s pupil.

As described above, according to various embodiments of the present invention, in order to provide correct eye coordination in an autostereoscopic display, in the present invention, instead of displaying two perspectives, Displays several sub-perspectives having vertical line-to-line distances of very small points, usually 20 to 40 times smaller.

The sub-perspectives are displayed very close to each other so that several of them are simultaneously recognized by the viewer's eyes and thus provide a second repeat state. The small line-to-line distance between sub-perspectives can be achieved by inserting a horizontal lens that is properly designed and positioned and providing a corresponding rendering of the graphics content. 2D eye tracking and viewing window control can be used to provide a super resolution state that displays a reduced number of perspectives that simultaneously provide viewer freedom and high image resolution.

The display according to the present invention is different from the conventional super-resolution technique as described in the example of 6,932,476, because it does not require many sub-perspectives to be displayed and the sub-perspectives are displayed in the vertical direction instead of the horizontal direction of the prior art .

Meanwhile, the present invention can be used not only in stereoscopic displays and monitors of all professional applications but also in consumer grade stereoscopic TVs.

While the present invention has been particularly shown and described with reference to exemplary embodiments thereof, it is to be understood that the invention is not limited to the disclosed exemplary embodiments, but, on the contrary, It will be understood by those skilled in the art that various changes in form and detail may be made therein without departing from the spirit and scope of the present invention.

21: Backlight unit 22: Image panel
23: Parallax part

Claims (20)

In a stereoscopic display apparatus,
An image panel for displaying an image through a set of vertical sub-perspectives in an interleaved form;
A panel controller for adjusting a vertical position of the displayed image;
A backlight unit having an output pupil controllable in at least a first main horizontal direction and providing light through eye / head tracking;
A backlight control unit for controlling the backlight unit;
An eye tracking sensor for detecting an eye position of a viewer and providing corresponding eye position data; And
And a parallax element arranged in a second main horizontal direction, the parallax element being designed to selectively display sub-perspectives having a predetermined first spacing in space,
Wherein the panel control unit and the backlight control unit receive the eye position data from the eye tracking sensor and control the image panel and the backlight unit based on the received eye position data,
Wherein the first interval is smaller than the diameter of the eye pupil. The method according to claim 1,
Wherein the parallax portion includes at least one of a lenticular lens array and a parallax barrier. The method according to claim 1,
Wherein the backlight unit comprises a one-dimensional light source array, a collimation optical system, and a directional diffuser. The method of claim 3,
Wherein the collimation optical system includes a wedge type light guide plate having a curved thick end combined with a prism sheet and a Fresnel lens. The method according to claim 1,
The parallax portion may be switched between an active state to provide eye-accommodation and an inactive state to provide a 3D stereoscopic image having a higher vertical resolution or to provide a 2D image The stereoscopic display device comprising: 6. The method of claim 5,
Wherein the parallax portion comprises a lenticular lens array made of an optically anisotropic material having a polarization switch for switching a lenticular lens between an active state and an inactive state. 6. The method of claim 5,
Wherein the parallax portion comprises a parallax barrier, the parallax barrier comprising an optical LCD panel switchable between a barrier mode and a transparent mode. The method according to claim 1,
Wherein the image panel and the backlight unit perform a field-sequential-color operation. In a stereoscopic image display method,
And selectively providing left and right eye images to the left and right eyes of a viewer to display a stereoscopic image,
Wherein the left and right eye images include a combination of low parallax sub-perspectives that are selectively displayed in space but very close enough that at least two or more sub-perspectives are simultaneously recognized by the viewer ' s eye. 10. The method of claim 9,
Wherein the sub-perspective sets are sequentially displayed, displayed in parallel, or sequentially displayed in parallel. 10. The method of claim 9,
Wherein the set of low parasitic sub-perspectives comprises a sub-perspective in which exit pupils are distributed along a vertical line. 10. The method of claim 9,
Wherein the set of low parasitic sub-perspectives comprises a sub-perspective in which exit pupils are distributed along a line that is inclined between +45 degrees and -45 degrees in a horizontal or horizontal direction. 10. The method of claim 9,
Wherein the motion of the viewer in the horizontal direction is provided based on the eye / head tracking or is provided based on the two sets of sub-perspective directive displays by the eye / head tracking. 10. The method of claim 9,
Wherein the motion of the viewer in the horizontal direction is provided based on a display state of the left and right sub-perspective sets having vertical polarization and utilization of polarizing glass by the viewer. 10. The method of claim 9,
Wherein the motion of the viewer in the horizontal direction is provided in different spectral regions based on the display state of the left and right sub-perspective sets and the use of spectrum spectacles by the viewer. 10. The method of claim 9,
Wherein the motion of the viewer in the horizontal direction is provided based on the display state of the left and right sub-perspective sets and the use of the shutter glass by the viewer in a time sequential manner. 10. The method of claim 9,
Wherein the viewer's movement in the horizontal direction is provided based on a display state of a plurality of horizontal sub-perspective sets. 10. The method of claim 9,
Wherein the motion of the viewer in the vertical direction is provided based on displaying a sub-perspective on the main lobe of the directional display and simultaneously displaying clones of sub-perspective on the upper and lower lobes of the directional display . A method for capturing a 3D image,
Capturing a perspective view using a camera at locations dispersed in a first horizontal direction (x direction) and a second vertical direction (y direction)
Wherein at least two positions in the first direction have parallax intervals defined by the interocular space and at least two positions in the second direction have parallax intervals defined by the pupil diameter of the eye. How to capture. In a stereoscopic display apparatus,
An image panel that displays an image through a vertical sub-perspective;
A panel controller for adjusting a position of the displayed image;
A backlight unit for providing light to the image panel through eye / head tracking;
A backlight control unit for controlling the backlight unit;
An eye tracking sensor for detecting an eye position of a viewer and providing corresponding eye position data; And
And a parallax element including a parallax element designed to selectively show vertical sub-perspectives having a predetermined first spacing,
Wherein the panel control unit and the backlight control unit receive the eye position data from the eye tracking sensor and control the image panel and the backlight unit based on the received eye position data.

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