JP2014524043A - Private video presentation - Google Patents

Abstract

  Embodiments relating to private video presentations are disclosed. For example, a system provided by one embodiment of the disclosure includes a display surface, a directional backlight system configured to emit a light beam from the display surface and to change the direction in which the light beam is directed, A spatial light modulator configured to form an image for display by light from the transmissive backlight system. The system is further configured to control the optical system and the light modulator to display a first video content item at a first viewing angle and to display a second video content item at a second viewing angle. Controller included.

Description

  The present disclosure relates to private (personal) video presentations.

  Many lamps have a light source in a housing configured to concentrate the light in a desired direction. For example, in the case of a searchlight or lighthouse, concentration can be said that light is collimated in that multiple rays of light appear in parallel. In many cases, it is also desirable to be able to scan the direction of light. This can be done with conventional lamps, for example, by rotating the entire lamp or by rotating lenses and mirrors around the light source. However, such a scanning mechanism may not be suitable for use in some devices, such as a display device, due to geometric and other factors.

  Various embodiments relating to providing a personal video presentation to one or more users are disclosed.

  For example, one embodiment of the disclosure includes a display surface, a directional backlight system configured to emit a light beam from the display surface and change the direction in which the light beam is directed, and a directional backlight system And a spatial light modulator configured to form an image for display by the light. The system further controls the directional backlight system and the spatial light modulator to display a first video content item at a first viewing angle and a second video content item at a second viewing angle. Including a controller configured to.

  This summary is presented to introduce a selection of concepts in a simplified form that are further described below in the detailed description. This summary is not intended to identify key features or essential features of the claimed matter, nor is it intended to be used to limit the scope of the claimed matter. Absent. In addition, the matters according to the claims are not limited to the implementation that solves any or all of the disadvantages mentioned in any part of the present disclosure.

1 illustrates one embodiment of a video presentation system configured to display images to one or more viewers with directed light. FIG. It is a typical top view showing one embodiment of an optical wedge. FIG. 3 shows a ray trace in the cross section of the embodiment of FIG. FIG. 3 shows a ray trace in the cross section of the embodiment of FIG. It is typical sectional drawing which expands and shows the end reflector of embodiment of FIG. FIG. 3 shows the ray trace in the embodiment of FIG. 2 as a path in the stack of a duplicate of the embodiment of FIG. FIG. 3 shows the ray trace in the embodiment of FIG. 2 as a path in the stack of a duplicate of the embodiment of FIG. FIG. 3 illustrates directed light scanning by injecting light at various locations along the thin edge of the optical wedge into the optical wedge of FIG. 2. FIG. 3 illustrates directed light scanning by injecting light at various locations along the thin edge of the optical wedge into the optical wedge of FIG. 2. 6 is a flow chart illustrating one embodiment of a method for scanning directed light. 6 is a flow chart illustrating one embodiment of a method of using light directed to display public and private information using different modes of a display device. 6 is a flowchart illustrating one embodiment of a method for displaying an autostereoscopic image using directed light. It is a figure which shows one Embodiment of the light injection system which has several light sources. 1 illustrates one embodiment of a light injection system having a single mechanically scannable light source. FIG. 1 illustrates one embodiment of a light injection system having an acousto-optic modulator, a laser, and a diffusive screen. FIG. 6 is a flowchart illustrating one embodiment of a method for simultaneously displaying different personal video presentations to a plurality of different viewers using directed light.

  Various embodiments are disclosed herein for presenting different images to different viewers watching the same display screen simultaneously. Some embodiments use a directional backlight such as a flat panel lamp. A directional backlight changes the angle of the light beam emitted by the backlight, leading different images to different viewers, leading different images to different eyes of a single viewer, Makes it possible to do so. A flat panel lamp is a panel having a planar surface that emits light. Such a lamp can be used, for example, as a backlight for a liquid crystal display (LCD) panel. Some flat panel lamps may have, for example, a plurality of fluorescent lamps housed in a housing having a diffuser plate through which light travels as it exits the panel. Other flat panel lamps may have a light wedge (optical wedge) for delivering light from the light source to the desired destination. An optical wedge is a light that allows the light input at one end of the optical wedge to fan out within the optical wedge by total reflection until it reaches the critical angle of total reflection and exits the optical wedge. It is a guide. While the embodiments described herein are described with respect to the situation of directed light scanning through a flat panel lamp, it will be appreciated that other embodiments use bulk optics as well. obtain.

  Current flat panel lamps are often used as diffuse light sources. However, in some situations, it has a sufficiently narrow viewing angle to guide a particular image to one viewer so that other viewers sitting near the viewer cannot see the image In a beam, it may be desirable to emit directional light from a flat panel lamp, whether collimated, divergent, or focused. For example, in some usage environments, an image can be viewed by an LCD panel so that the image can be viewed only from a specific angle, thereby leaving the display information private to the intended viewer May be desirable. Using a directed light beam for the backlight of an LCD panel may allow the construction of such a display. This is because the image on the display can be seen only when light rays travel from the display to the viewer's eyes. When using a focusing light beam, the light beam can be configured to focus at the location of the user's eye. Thus, a significant portion of the light used to create the image can reach the user, thereby providing efficient power usage while maintaining the privacy of the presentation.

  Also, when using such a display, it may be desirable to be able to scan the illumination direction so that the angle at which the image can be viewed can be moved. Furthermore, while the image on the liquid crystal panel is switched between a pair or a plurality of pairs of views of a three-dimensional object, the illumination direction can be quickly switched back and forth between a pair of eyes or a plurality of pairs of eyes. In some cases, a single display can simultaneously display different images to multiple different users, display a 3D image to one or more users without using filtering glasses, and other such usage situations. Can be achieved. Thus, disclosed herein are embodiments relating to a directional image display system that includes, but is not limited to, using a flat panel lamp as directional backlight illumination and that allows scanning the direction of light. Note that in the accompanying drawings, the drawings of the illustrated embodiments may not be drawn to scale, and the aspect ratios of some mechanisms may be exaggerated to make certain mechanisms or relationships easier to see. is there.

  FIG. 1 illustrates one embodiment of a video presentation system in the form of a computing device having a display surface configured to output directed light. The video presentation system 10 includes a spatial light modulator 12 and an optical scanning system. The spatial light modulator 12 has a plurality of pixels in an array in which each pixel can be used to modulate the light from the backlight with respect to color and intensity. In some embodiments, the spatial light modulator may have a liquid crystal display, but other light modulators may be used as well. For example, a controller such as controller 14 may provide display data to spatial light modulator 12. When there is a viewer 15 in the light path of the directed light and the directed light is modulated by the spatial light modulator 12 with the image supplied from the controller 14, the image is viewed by the viewer 15. Can be visible.

  The video presentation system 10 further includes a light injection system 16 and a light wedge 100. Some embodiments may further include an optional user tracking camera 18 and an optical redirector 20 disposed adjacent to the display surface of the optical wedge 100. As will be described in more detail below, when light is injected into the thinner end surface (thin end surface) of the optical wedge 100, the directed light is emitted from the display surface of the optical wedge 100. This directed light exits the optical wedge 100 at a small angle with respect to the plane of the display surface of the optical wedge 100. The light redirector 20 can be used to redirect this collimated light toward the spatial light modulator 12. As the optical redirector 20, any suitable structure may be used. In some embodiments, the light redirector 20 can include a prismatic film, for example.

  The light injection system 16 may be configured to inject light at one or more locations along the thin end surface of the light wedge 100. By changing the position where light is injected into the thin end surface of the optical wedge 100, the direction of the light leaving the display surface of the optical wedge 100 can be adjusted. By changing the direction of the light in synchronization with the change of the image generated by the spatial light modulator, different images can be displayed to different viewers. Also, when modulated at a sufficiently high frequency, both images can appear to their viewers as being displayed continuously without noticeable flicker. Thus, referring to FIG. 1, when the first image is directed to the viewer 15, the first image may be visible to the viewer 15 but not visible to the viewer 17. . This is indicated by the solid ray trace in FIG. Similarly, when the second image is directed to the viewer 17, the second image may be visible to the viewer 17 but not visible to the viewer 15. This is indicated by the dashed ray trace in FIG. Although FIG. 1 shows the situation of two viewers, as will be appreciated, a personal video presentation may be directed to any suitable number of viewers simultaneously. As will be further understood, the terms “first” and “second” as used herein with reference to viewers, video presentations, images, and the like, refer to two or more viewers, videos. This is merely for convenience in describing a set of presentations, images, etc., and is not intended to be limiting in any way.

  In one specific example embodiment illustrated in FIG. 13, the light injection system 16 is disposed adjacent to the thin end surface of the light wedge 100, such as a light emitting diode (LED), laser, lamp, and / or other suitable light source. It may have a plurality of individually controllable light sources. Changing the light source that is brightened, or multiple light sources that are brightened simultaneously, allows to control the direction in which the directed light is emitted from the light wedge 100. For example, a single light source 1302 among the plurality of light sources in FIG. 13 can be brightened. Similarly, multiple light sources may be brightened simultaneously to direct multiple image beams in different directions. In other embodiments, such as illustrated in FIG. 14, for example, a single mechanically scanable light source 1402 may be used to change the position along the thin edge of the light wedge 100 into which light is injected. . The position of this light source can vary from one side of the optical wedge 100, such as position 1404, to the opposite side of the optical wedge 100, such as position 1406, for example. In yet another embodiment, for example as illustrated in FIG. 15, the light injection system 16 may include a light source 1502 and a diffusive screen 1504. The diffusive screen 1504 is positioned adjacent to and extending along the thin end surface of the light wedge 100. When the laser beam generated by the light source 1502 is guided to the diffusive screen 1504 and the diffused light is reflected from the diffusive screen 1504 into the thin end surface of the light wedge 100, light is injected into the thin end surface of the light wedge 100. Can be done. The light source 1502 may include a laser and an acousto-optic modulator or liquid crystal hologram for controlling the orientation of the laser beam. The laser beam may be directed to location 1506 as shown. Alternatively, the laser beam may be scanned from one side of the diffusive screen 1504, eg, location 1508, to the opposite side of the diffusive screen 1504, eg, location 1510.

  Since the light wedge 100 is configured to form directed light having a relatively narrow viewing angle, injecting light from a single location will cause the directed light to be emitted in a single direction. So that the projected image can only be viewed from a narrow angular range. This may allow information to be displayed in a private mode where the image targets a particular viewer. On the other hand, injecting light from two or more locations simultaneously allows directed light to be emitted in more than one direction, thereby viewing the projected image from a wider angular range. Can be able to. Here, such a display mode is referred to as a public mode. As will be appreciated, these display mode examples are described for illustrative purposes and are not intended to be limiting in any way.

  Referring to FIG. 1, the controller 14 may be configured to illuminate each light source of the light injection system 16 independently and selectively according to the mode of the system. Thus, the controller 14 can control the position along the light wedge lamella where the light injection system 16 injects light. Controller 14 may also be configured to provide display data to spatial light modulator 12 and receive data from user tracking camera 18. Data from head tracking camera 18 may be analyzed by controller 14 to determine the position of the viewer's head, eyes and / or other human body parts. The data from the user tracking camera 18 may be raw (raw) image data or may be preprocessed so that various features of the image are extracted before the data is transferred to the controller 14. Good. Any suitable image sensor or combination of sensors may be used with the user tracking camera 18. For example, a two-dimensional image sensor may be used in some embodiments, and a depth sensor may be used in other embodiments. Similarly, in some embodiments, both a two-dimensional image sensor and a depth sensor may be used. In embodiments that use depth sensors, any suitable depth sensing technique may be used, including but not limited to time-of-flight, structured light, and / or stereo image sensing, In addition, an estimation algorithm such as a human body size and a head size for estimating the depth based on the size of the body visible in the two-dimensional image is included.

  In some embodiments, the controller 14 may also determine and store the mode of the video presentation system 10 and control the video presentation system 10 according to that mode. The controller 14 may be any computing device configured to execute instructions that may be stored on a computer readable storage medium such as, for example, the memory 22. The processor 24 can be used to execute instructions stored in the memory 22, which instructions include routines for executing the control method of the video presentation system 10.

  Video presentation system 10 may further include a personal audio output system 30 configured to provide a personal audio output corresponding to the personal video presentation. Personal audio output system 30 may be configured to provide personal audio output in any suitable manner. For example, in some embodiments, one or more phased array speaker sets can be used to form an audio beam directed to a user. In such embodiments, the user tracking camera 18 can be used to determine the direction of each audio beam. If the user tracking camera 18 has a depth camera or other depth determining mechanism (eg, visible human / head size comparison), the depth data is utilized so that the audio from the phased array speaker interferes constructively. The configured depth can be determined. In other embodiments, parabolic speakers or other directional speakers may be used to provide personal audio output. As a more specific example, in one embodiment configured to support viewing two simultaneous personal video presentations, two viewers using two parabolic speakers to view different video content items Personal voice can be directed to the right. Such directional speakers can be moved to change the direction of the audio output as the viewer physically moves within the video viewing environment as detected by the head tracking camera 18 (eg, by a motor). ). In yet another embodiment, wireless or wired headphones may be used to provide personal audio via a wireless communication system that includes a wireless transmitter. For wireless headphones, any suitable mechanism for associating a particular headphone set with a particular user may be used, including but not limited to the line of sight between headphone sets (line of sight). ) Communication channel (eg, infrared or other) and / or user input made in response to an identification audio signal transmitted to each headphone set.

  Video presentation system 10 may be configured to obtain video content from any suitable source or sources. For example, in one specific embodiment, video presentation system 10 may have multiple television tuners to allow multiple users to watch different television programs simultaneously. In other embodiments, video presentation system 10 may receive input from other sources or combinations of sources, such as, for example, a DVD player, a computer network, a video game system, and the like. FIG. 1 illustrates such a video input as an audio / video (“A / V”) source input 1 and an arbitrary A / V input N. Multiple video content items received from multiple sources for simultaneous presentation are multiplexed and provided to the spatial light modulator in any suitable manner to allow simultaneous display of the multiple video content items Can be done.

  As will be appreciated, the video presentation system 10 is described for illustrative purposes, and the optical system according to the present disclosure may be used in any suitable use environment. Also, as will be appreciated, a video presentation system such as that shown in the embodiment of FIG. 1 may include a variety of other systems and capabilities not shown, including but not limited to a vision-based or other touch detection system. Can be included.

  Next, referring to FIG. 2, the optical wedge 100 has a thin end surface 110 of the optical wedge 100 such that directional light exits the display surface 150 of the optical wedge 100 as shown by a ray trace in FIG. 2. Is configured to direct light from the light source 102 disposed adjacent thereto. The term “display surface” indicates that the display surface 150 is closer to the viewer than the back surface opposite the display surface 150 (not visible in FIG. 2). The display surface and the back surface are bounded by side surfaces 130 and 140, a thin end surface 110, and a thicker end surface ("thick end surface") 120, respectively. In FIG. 2, the display surface 150 faces a person viewing the paper surface, and the back surface is hidden by the depiction of the optical wedge 100.

  The optical wedge 100 is configured such that the light beam injected into the optical interface of the thin end surface 110 spreads in a fan shape through total reflection as it approaches the thick end surface 120 having an end reflector (end reflector) 125. The In the illustrated embodiment, the end reflector 125 is curved with a uniform radius of curvature having a center of curvature 200, and the light source 102 is injecting light at the focal point of the end reflector 125, which focal point is at the radius of curvature. At a half position, collimated (parallel) light is formed. In other embodiments, the light source may have other suitable locations to create other desired light beams (eg, focusing or diverging). At the thick end face 120, each ray is reflected by the end reflector 125 parallel to each of the other rays. These rays travel from the thick end surface 120 toward the thin end surface 110 until they intersect the display surface 150 at the critical angle of reflection of the display surface 150 and emerge as directed light. In an alternative embodiment, the end reflector 125 may be parabolic or have other curvature and / or configuration suitable for directing light.

  In embodiments having a plurality of light sources disposed adjacent to and along the thin end surface 110, the light source on either side of the centerline 210 is the focal point of the end reflector 125 to correct field curvature and / or spherical aberration. It is desirable to slightly shorten the sides 130 and 140 of the optical wedge 100 so that they can stay inside. Shortening the sides 130 and 140 can result in the thin end face 110 being convex as illustrated by the curve 115. The preferred curvature is by using a ray-tracing algorithm to trace the ray at the critical angle of reflection of the display surface 150 of the optical wedge 100 back in the optical wedge 100 until it reaches a focal point near the thin end 110. Can be found.

  3 and 4 show ray traces in a schematic cross section of the optical wedge 100. FIG. 3 shows the path of the first light ray 300 in the optical wedge 100, FIG. 4 shows the path of the second light ray 400 in the optical wedge 100, and the light rays 300 and 400 are on the thin end face 110 of the optical wedge 100. It represents light rays positioned on opposite sides of the input conical light. As can be seen in FIGS. 3 and 4, the light beam 300 exits the display surface 150 near the thin end surface 110 of the light wedge 100, while the light beam 400 is close to the thick end surface 120 of the light wedge 100. Exit display surface 150.

  Rays 300 and 400 exit the display surface 150 when they intersect the display surface 150 at a critical angle of total reflection or less with respect to the normal of the display surface 150. This critical angle is sometimes referred to herein as a “first critical angle”. Similarly, a light ray internally reflects within the light wedge 100 when it intersects the display surface 150 at an angle greater than the first critical angle of total reflection with respect to the normal of the display surface 150. The light ray is internally reflected in the optical wedge 100 when it intersects the back surface 160 at an angle larger than the critical angle of total reflection with respect to the normal line of the back surface 160. This critical angle is sometimes referred to herein as a “second critical angle”.

  As will be described in more detail with reference to FIG. 5, the first critical angle and the second critical angle are set such that light incident on the back surface 160 is reflected back to the display surface 150 at the first critical angle. It is desirable to be different. This helps to prevent loss of light through the back surface 160 and thus can increase the optical efficiency of the optical wedge 100. The first critical angle is a function of the refractive index of the optical wedge 100 and the refractive index of the material (for example, air or a layer of cladding (cladding layer)) that contacts the display surface 150, and the second critical angle is , A function of the refractive index of the optical wedge 100 and the refractive index of the material adjacent to the back surface 160. In some embodiments, such as those shown in FIGS. 3 and 4, for example, the display surface 150 may be in contact with air and only the back surface 160 may be provided with a layer 170 of dressing. In other embodiments, the display surface 150 may have a layer of coating material (not shown) having a different refractive index than the back surface 160.

  Any suitable one or more materials may be used as the cladding layer in order to achieve the desired critical angle for internal reflection of the display and / or back of the optical wedge. In one example embodiment, the optical wedge 100 is formed from polymethyl methacrylate or PMMA having a refractive index of 1.492. The refractive index of air is approximately 1.000. Therefore, the critical angle of the surface without the coating is approximately 42.1 °. Similarly, an example of the cladding layer may have Teflon AF (a registered trademark of DuPont), that is, an amorphous fluoropolymer having a refractive index of 1.33. The critical angle of the PMMA surface coated with Teflon AF is 63.0 °. As will be appreciated, these examples are described for illustrative purposes and are not intended to be limiting in any way.

  The configuration of the optical wedge 100 and the end reflector 125 is such that when the uniform light is injected into the thin end surface 110, the majority of the display surface 150 is illuminated uniformly, and the majority of the injected light is It can be set to cause the display surface 150 to exit. As described above, the optical wedge 100 is tapered in the length direction so that the light beam injected into the thin end surface 110 is transmitted to the end reflector 125 through total reflection. The end reflector 125 has a faceted lens structure that is configured to reduce a light ray angle with respect to each normal line of the display surface 150 and the back surface 160. In addition, the thickness of the optical wedge 100 that gradually decreases from the thick end surface 120 to the thin end surface 110 reduces the ray angle with respect to the normal of each surface as the light rays travel toward the thin end surface 110. When the light beam enters the display surface 150 at an angle smaller than the first critical angle, the light beam exits the display surface 150.

  In some embodiments, the light source 102 may be positioned at the focal point of the end reflector 125 (in other embodiments, the light source 102 may be placed in other suitable locations). In such an embodiment, the end reflector 125 may be curved with a radius of curvature that is twice the length of the optical wedge 100. 3 and 4, the taper angle of the optical wedge 100 is such that the corner portion of the thick end surface 120 and the display surface 150 has a right angle and the corner portion of the thick end surface 120 and the back surface 160 has a right angle. Set to When the thin end surface 110 is at the focal point of the end reflector 125, the thin end surface 110 is ½ of the thickness of the thick end surface 120. In other embodiments, each of these structures may have other suitable configurations.

  In the illustrated embodiment, the end reflector 125 is spherically curved from the side surface 130 to the side surface 140 and from the display surface 150 to the back surface 160. In another embodiment, the end reflector 125 is cylindrical with a uniform radius of curvature from the display surface 150 and the back surface 160, with the center of curvature being where the display surface 150 and the back surface 160 meet when the display surface 150 and the back surface 160 are extended. May be curved. A cylindrically curved end reflector can have fewer sag (ie, a curved portion that cannot be used as a display area) than a spherically curved end reflector 125, which can be advantageous in large format applications. Other suitable curvatures may also be used for the end reflector 125, such as a parabolic shape. Further, the curvature of the end reflector 125 in a plane perpendicular to the side surfaces 130 and 140 is different from the curvature of the end reflector 125 in a plane parallel to the side surfaces 130 and 140, such as a toroidal (doughnut) reflector. It may be.

  As described above, the critical angles of reflection of the display surface 150 and the back surface 160 are preferably different to help prevent loss of light through the back surface 160. This is shown in FIG. 5 which shows a schematic enlarged cross-sectional view of the end reflector 125 of the optical wedge embodiment of FIGS. 2-4. The end reflector 125 has a faceted lens structure having a plurality of facets (facets) arranged at an angle with respect to the surface of the thick end face 120. The plurality of facets are alternated between a facet facing the display surface such as facet 530 and a facet facing the back surface 160 such as facet 540. The end reflector 125 follows the overall curvature as described above, with the end reflector normal 542 and the end reflector normal 532 extending toward the center of curvature. Each of the plurality of facets has a certain height and an angle with respect to the normal of the surface of the end reflector. For example, one of the facets facing the display surface 150 has a height 538 and a relative angle 536 between the end reflector normal 532 and the facet normal 534. As another example, one of the facets facing the back surface 160 has a height 548 and a relative angle 546 between the end reflector normal 542 and the facet normal 544.

  The height of each of the plurality of facets can affect the uniformity and brightness of the light beam exiting the display surface 150. For example, a larger facet can create an optical path that is different from the ideal focal length, thereby causing Fresnel banding. Thus, in embodiments where such banding can be a problem, it is desirable to have each facet height less than, for example, 500 μm so that such banding is less visible.

  Similarly, the angle of each of the plurality of facets can affect the uniformity and brightness of the directed light beam exiting the display surface 150. Ray 500 illustrates how facet angles can affect the path of rays within optical wedge 100. The light beam 500 is injected into the thin end face 110, travels through the light wedge 100, and strikes the end reflector 125. Half of the light beam 500 strikes the facet 530 facing the display surface 150. The portion of the light ray 500 that strikes facet 530 is reflected as light ray 510 toward display surface 150. The light ray 510 intersects the display surface 150 at an angle equal to or smaller than the first critical angle of internal reflection with respect to the normal line of the display surface 150, and thus exits the display surface 150 as a light ray 512.

  The other half of the ray 500 strikes a facet 540 that faces the back surface 160. The portion of the light beam 500 that strikes facet 540 is reflected toward back surface 160 as light beam 520. Due to the critical angle difference between the display surface 150 and the back surface 160, the light ray 520 intersects the back surface 160 at an angle greater than the second critical angle of internal reflection with respect to the normal of the back surface 160, and thus The light beam 522 is reflected toward the display surface 150. The light ray 522 intersects the display surface 150 at an angle equal to or smaller than the first critical angle of internal reflection with respect to the normal line of the display surface 150, and thus exits as a light ray 524. Thus, most of the light reflected from the end reflector 125 leaves the display surface 150.

  When the light is reflected separately by the facet facing the display surface 150 and the facet facing the back surface 160, the light is reflected from the back surface so as to exit the display surface. Overlapping and superimposed first and second images arranged in the direction are formed on the display surface 150. The degree of overlap between these images can be determined by the angle of facets 530 and 540. For example, as described in more detail below, when each facet has an angle of 3/8 of the difference between 90 ° and the first critical angle of reflection with respect to the normal of the surface of the end reflector, these 2 The two images overlap completely. In this example, substantially all light input to the optical wedge 100 exits the display surface 150. Changing the facet from this value will reduce the amount of overlap between images, if the facet angle is 1/4 or 1/2 of the difference between 90 ° and the first critical angle of reflection. Only one of the two images or only the other is displayed. Also, changing the facet angle from 3/8 of the difference between 90 ° and the first critical angle of reflection is also that some light is not from the display surface 150 but from the thin end face of the light wedge 100. I will let you go out. If the facet angle is 1/4 or 1/2 of the difference between 90 ° and the first critical angle of reflection, the display surface 150 can again be illuminated uniformly, but half of the light is light It goes out of the thin end face of the wedge 100 and is therefore lost. As will be appreciated, depending on the desired use environment, it may be preferable to use a facet angle other than 3/8 of the difference between 90 ° and the first critical angle of reflection. Such usage environment is not limited to the following, but is an environment where non-overlapping areas of light (which will appear to have a lower intensity than the overlapping areas) are outside the field of view observed by the user. As well as environments where attenuated light intensity is acceptable.

  In an alternative embodiment, the end reflector 125 may have a diffraction grating. The diffraction grating equation can be used to calculate the diffraction angle for a given incident angle and a given wavelength of light. Since the diffraction angle depends on the wavelength of light, an end reflector with a diffraction grating may be desirable when the incoming light is monochromatic.

  FIGS. 6 and 7 illustrate the light progression in the optical wedge 100 to further illustrate the concept illustrated in FIG. 5 by stacking multiple optical wedges, each of which is a replica of the optical wedge 100 of the above-described embodiment. It is shown as a ray path in Tracing with rays in a stack of multiple replicas of a single optical wedge is optically equivalent to tracking the path of the rays within a single optical wedge. Thus, in this way, each internal reflection of the light beam is shown as a path through the boundary from one light wedge to the adjacent light wedge. In FIG. 6, the display surface is shown as the top wedge display surface 620 in the optical wedge stack 600. The back side is shown as the bottom wedge back 630 in the stack of optical wedges 600. The thick end faces of the plurality of optical wedges of the stack 600 combine to form a curve 640 that is approximately the axis 610 around which all surfaces converge.

  FIG. 6 also depicts two rays 650 and 660 that are located on opposite sides of the conical light that is injected into the thin end face of the optical wedge stack 600. For each ray 650 and 660, after reflection from the end reflector, half of the rays indicated by lines 652 and 664 emerge near the thick end face of the optical wedge stack 600 (and hence from the optical wedge represented thereby) Half of the rays indicated by lines 654 and 662 appear near the thin end face of the optical wedge stack. Rays injected at an angle between these two extreme angles will also be separated by the facet pattern of the end reflector and will likewise emerge from the display and back surfaces of the light wedge. Rays exiting display surface 620 parallel to rays 652 and 662 are represented by shaded area 602. As will be appreciated, as described above, the light beam shown to be emitted through the optical wedge back surface 630 has a lower refractive index than the coating (not shown) used for the display surface of the optical wedge. By using a covering material (not shown) on the back side of the optical wedge, instead of being emitted through the back side, it can be emitted from the display surface after being reflected by the back side. Thus, substantially all of the light injected into the thin end face of such a light wedge can be emitted from the display surface of the light wedge.

  On a uniformly illuminated display surface (eg, when the image reflected from facet 530 and the image reflected from facet 540 completely overlap), it is injected into the thin end surface and travels sideways toward the end reflector. Rays that coincide with the normal of the end reflector are reflected at the facets facing the display surface, travel to the center of the display surface, and intersect the display surface at the critical angle of the display surface. FIG. 7 schematically depicts such a ray path in a stack 700 of light wedges. The light beam 710 is injected at the thin end surface 702 of the optical wedge and reflected by the end reflector 704 as the light beam 715. Light ray 715 travels to the center of display surface 706 and intersects display surface 706 at a critical angle of reflection 730 with respect to display surface normal 720. The sum of angles 732 and 734 is the difference between 90 ° and the critical angle of reflection 730. When the thin edge of the optical wedge is 1/2 the thickness of the thick edge of the optical wedge, the center point of the wedge is 3/4 of the thickness of the wedge. Using the paraxial approximation, the angle 732 is 3/4 of the difference between 90 ° and the critical angle of reflection 730. Since the horizontal straight line 722 is parallel to the injected ray 710, the angle 740 is equal to the angle 732. From the law of reflection, the incident angle is equal to the reflection angle, so the facet angle is 1/2 of the angle 740. Thus, in a uniformly illuminated display surface, as described above, each facet facing the display surface has a difference between 90 ° and the critical angle of reflection 730 with respect to the normal of the surface of the end reflector. An angle of 3/8 can be formed.

  8 and 9 show how the direction of the directed light beam changes by injecting light into the optical wedge of FIG. 2 at different locations along the thin edge of the optical wedge. Yes. Specifically, by shifting the light injection position to the right, the direction of the light beam can be moved to the left, and vice versa. In each figure, for the sake of clarity, the visible position of a single pixel of light, shown as 800 and 900 in FIGS. 8 and 9, respectively, is shown. Also, a straight line traced from this point of light to the corner of the optical interface of the optical wedge is shown and to further clearly illustrate the movement of the light pixel relative to the optical wedge when the light injection position is moved. A center line 810 is shown.

  In FIG. 8, light is injected from the light source 802 in the first position to the right side of the thin end surface 110. The direction of the light beam is directed to the left of the center line 810 as indicated by the pixel at the visible position 800. In FIG. 9, light is injected from the light source 902 in the second position to the left side of the thin end surface 110. The direction of the light beam is to the right of the center line 810 as indicated by the pixel at the visible position 900. As will be appreciated, the light beam can be smoothed in the desired size and in the desired order by sequentially changing the position of light injection along the thin end face of the optical wedge 100 in the desired time interval and in the desired order. Or it can scan in steps. Here, such a display mode may be referred to as a scanning mode.

  FIG. 10 shows a flowchart of an example of a method for scanning collimated light with an optical waveguide. The optical waveguide may have a first end and a second end surface opposite to the first end surface. The optical waveguide may also include an end reflector, a display surface extending between the first end surface and the second end surface, and a back surface opposite to the display surface. In one embodiment, the optical waveguide is the optical wedge of FIG. 2, the thin end surface of the optical wedge is the first end surface of the optical waveguide, and the thick end surface of the optical wedge is the second end surface of the optical waveguide.

  In another embodiment, the optical waveguide may have a certain thickness, for example, the first end face and the second end face are the same thickness. Such an optical waveguide may include a coating material having a refractive index that linearly changes between the first end surface and the second end surface on the display surface and / or the back surface. This embodiment operates in the same way as an optical wedge when light is injected into the first end face of the optical waveguide. In yet another embodiment, the optical waveguide has a certain thickness, a refractive index that varies linearly between the first end surface and the second end surface, and a constant on the display surface and / or the back surface. A refractive index coating. This embodiment also operates in the same way as an optical wedge when light is injected into the first end face of the optical waveguide.

  Returning to FIG. 10, method 1000 begins at step 1010 by injecting light into the first end face of the optical waveguide. As described above, the light can be injected, for example, by a light source configured to be mechanically moved along the first end face of the light guide. In another embodiment, a plurality of light sources are arranged along the first end face of the optical waveguide, and each light source is applied to the first end face of the optical waveguide at a different position along the first end face of the optical waveguide. May be configured to be injected. Light can be injected by one or more of these multiple light sources. In yet another embodiment, the light is injected by scanning the laser beam across a diffusive screen positioned adjacent to and extending along the first end face of the optical waveguide. May be.

  Next, in step 1020, the injected light is delivered to the end reflector via total internal reflection. At step 1030, the light may be internally reflected at the end reflector. Light internally reflected at the end reflector may be reflected from the first set of facets and the second set of facets. Each of the first set of facets has a normal at least partially facing the display surface, and each of the second set of facets has a normal at least partially facing the back surface. Have. Also, in some embodiments, each of the first set of facets has an angle of 3/8 of the difference between 90 ° and the critical angle of reflection, and each of the second set of facets , Having an angle of 3/8 of the difference between 90 ° and the critical angle of reflection. In other embodiments, the facets may have other suitable angles that do not cause undesirable variations in light intensity. In yet another embodiment, the end reflector may include a diffraction grating.

  Depending on the angle attached to the facets on the end reflector, at step 1040, the portion of light that intersects the display surface at the critical angle of reflection may be emitted from the display surface. Next, at step 1050, the position along the first end face of the optical waveguide where light is injected into the optical waveguide may be changed. In one embodiment, the position along the first end face of the light guide is changed by mechanically moving the light source to the desired position, and light can be injected by the light source at the desired position. In another embodiment, the position along the first end face of the light guide is changed by selectively brightening one light source from a plurality of light sources arranged along the first end face of the light guide. obtain. In yet another embodiment, the location along the first end face of the light guide traverses a diffusive screen positioned adjacent to and extending along the first end face of the light guide. And can be changed by scanning the laser. By changing the position where light is injected, the direction of the light beam can be changed. As illustrated in FIGS. 8 and 9, by injecting light into the left side of the thin end surface 110 of the optical wedge 100, collimated light can be emitted in the right direction of the optical wedge 100, and vice versa. is there.

  FIG. 11 is a flowchart of an example embodiment of a method that may be used to perform a method that uses a light beam to display public and private information during different modes on the same optical system, such as, for example, video presentation system 10. Is shown. Before describing FIG. 11, as will be appreciated, the use of the term “wedge” in the description of FIGS. 11-12 and 16 demonstrates the availability of this embodiment as a light wedge type light guide. Is not intended to be limiting, and light guides having varying refractive indices as described above may also be used.

  Returning to FIG. 11, at step 1110, the display mode of the optical device is determined. If the display mode is public mode, the routine proceeds from step 1110 to step 1150. If the display mode is the private mode, the routine proceeds to step 1120.

  When the display mode is private, the viewer's location may be determined at step 1120. The viewer's position can be determined by the controller 14 using, for example, head tracking data received from the head tracking camera 18 or can be assumed to be directly in front of the video presentation system 10. At step 1130, the viewer's position may be associated with one or more positions along the thin edge of the light wedge. The location along the thin edge of the light wedge can be selected, for example, such that the viewer is in the optical path of the light beam emitted from the video presentation system 10 when light is injected at each of the locations. . At step 1140, light may be injected at the one or more locations along the thin edge of the light wedge. By injecting light from a single light source to a single location, the narrowest field of view of the video presentation system 10 can be provided. However, it may be desirable to expand the field of view by injecting light at more than one location. Widening the field of view may provide a margin when the calculated viewer position is not accurate, such as when the head tracking algorithm is slow compared to the speed of the viewer's movement. As will be appreciated, the field of view may be controlled by the user of the display so that a single personal image is displayed to any number of users in preferred locations around the display. The routine ends after step 1140.

  The method 1100 may be continuously repeated in a loop so that the viewer's position may be updated if the viewer moves. By updating the viewer's position and the position along the thin edge of the associated optical wedge, the light beam from the video presentation system 10 can follow the viewer as the viewer moves.

  When the display mode is public, at step 1150, a wide field of view may be associated with multiple positions along the thin edge of the light wedge. For example, in some situations, all of the light sources may be illuminated simultaneously, or a subset of the light sources may be illuminated simultaneously. In either case, as shown in step 1160, light is injected into the plurality of positions along the thin end surface of the optical wedge, and the image can be displayed with a wide field of view.

  Public mode display can be used in various ways to display one image to various numbers of viewers. For example, it may be desirable to display an image to any user who can view the display screen directly. In this case, a wide field of view can be obtained by illuminating all light sources of a plurality of light beams arranged along the thin end surface of the optical wedge. On the other hand, some uses of the public mode may exhibit certain personal display characteristics. For example, the display may be configured so that each bank teller and customer can see an image that is hidden from those viewing the display at a different angle than the bank teller or customer. In such a mode, the direction in which the light is directed may be predetermined based on the intended viewer's seat / standing position, or may be determined by a camera or other suitable technique.

  In some embodiments, a stereoscopic image is provided to each viewer of a personal image by sequentially providing different images to the viewer's right eye and left eye for each frame of video data. Can be presented. For example, in some such embodiments, the image may be displayed with each pixel of the display panel visible to only one eye in any frame and only to the other eye in subsequent frames. In other such embodiments, the image may be displayed in any other suitable manner (eg, with a suitable amount of overlap). FIG. 12 shows a flowchart of an example embodiment of a routine used to perform a method for displaying an autostereoscopic image with directed light. Here, such a display mode may be referred to as an autostereoscopic mode. At step 1210, the viewer's first eye position and second eye position are determined via the head tracking camera. At step 1220, the first image and the first position along the thin edge of the light wedge are associated with the viewer's first eye. The first image may be, for example, a view of a three-dimensional object viewed by the viewer's left eye. The left eye may be in the optical path of the directed light emitted by the video presentation system 10 when light is injected at a first location along the thin edge of the light wedge. At step 1230, the first image is modulated by the spatial light modulator 12, and at step 1240, light is injected at a first position along the thin edge of the light wedge, thereby causing the first image to be Presented to the first eye.

  At step 1250, the injection of light to the first position along the thin edge of the optical wedge is stopped, and at step 1260, the second image and the second position along the thin edge of the optical wedge are Is associated with the viewer's second eye. The second image may be, for example, a view of a three-dimensional object viewed by the viewer's right eye. The right eye may be in the optical path of the light emitted by the video presentation system 10 when light is injected at a second location along the thin edge of the light wedge. In step 1270, the second image is modulated by the spatial light modulator 12. At step 1280, light is injected at a second location along the thin edge of the light wedge so that a second image can be presented to the user's second eye.

  At step 1290, the injection of light to the second position along the thin edge of the light wedge is stopped. Thereafter, the method 1200 may be repeated sequentially so that the first image set is displayed for one eye and the second image set is displayed for the other eye. If this routine is repeated fast enough, for example, if the refresh rate is high enough, the viewer's eyes may integrate these time multiplexed images into one flicker-free scene. A refresh rate higher than 60 Hz is desirable, although the way the viewer feels is different.

  Embodiments of the disclosed video presentation system may also be used to present a view-dependent depiction image in which the viewpoint of an object in the image changes when the viewer's viewpoint on the display screen changes. To create this effect, a plurality of laterally adjacent images can be quickly displayed one after the other, with each image being visible from a slightly different viewing angle. For example, in one embodiment, a plurality of laterally adjacent images may include 32 images representing 32 views of a 2D or 3D scene. Since each eye of the viewer looks at the display at a slightly different angle, each eye can see a different image, and at this time, the image to be viewed depends on the user viewpoint of the display screen. Similarly, instead of continuously displaying a plurality of laterally adjacent images, only line-of-sight tracking techniques may be used to display only images currently in the user's field of view. Further, such a view-dependent depiction image can be provided to a plurality of viewers so that different images are presented to each eye of each user. Such a method may give one or more viewers the impression that they are viewing the display image through a window due to a change in viewpoint as a function of each viewer's head / eye position movement.

  As mentioned above, in some embodiments, the light from the backlight system may be configured to focus at the position of the viewer's eyes. The video presentation system 10 of FIG. 1 may allow autostereoscopic viewing when the spatial light modulator 12 is small (eg, sized to the pupil). As the spatial light modulator 12 increases in size, the video presentation system 10 may have additional optical elements, such as a Fresnel lens, adjacent to the spatial light modulator 12.

  FIG. 16 shows a flowchart illustrating another embodiment configured to simultaneously display a personal video presentation (either the same presentation or different presentations) to multiple viewers. Method 1600 begins at step 1610, where multiple viewers are detected, for example, by image sensor data. Then, at step 1620, the personal image / sound output is associated with each viewer. Any suitable output may be associated with each viewer, for example, a video content item or a content discovery screen where the viewer can select a video content item for personal consumption.

  At step 1625, personal audio is provided to each viewer. Personal audio may be provided in any suitable manner. For example, in some embodiments, each user may use a wired or wireless headphone set that can be tied to a particular viewer. As a more specific example, a wireless headphone set receives line-of-sight in response to a request transmitted by a video presentation system over a wireless communication channel (eg, Bluetooth, WiFi, or other suitable wireless communication channel). It can be set to emit a (line of sight) signal (eg, an infrared beacon). The line-of-sight signal may be detected by a head tracking camera or may be detected in other suitable manners. In another embodiment, user feedback may be used to tie the headphone set to a particular user. For example, an audio signal may be transmitted to each headphone set, requesting each user to make a gesture that can be detected by the head tracking camera in sequence. In embodiments that use directional speakers to output personal audio, such a headphone association process may be omitted. This is because the audio output for a video content can be directed in the same direction as the video output.

  Next, at step 1630, method 1600 includes setting the first viewer as the current viewer. Then, at step 1640, the position of the current viewer is determined and that position is associated with a position along the thin edge of the light wedge that will cause light to be directed at the current viewer. The current viewer position may be determined in any suitable manner. For example, the location may be determined by using head tracking data or may be predetermined (eg, multiple location numbers and locations may be controlled and / or set by a user or administrator). . As will be appreciated, the position at which light is injected for a particular user can be adjusted repeatedly as the viewer moves within the viewing environment tracked by the head tracking camera. Similarly, as indicated at step 1645, the direction of the personal audio output, eg, an audio beam, can be adjusted when the user moves.

  Next, at step 1650, the spatial light modulator is modulated to produce an image for the current viewer. In some examples, an image is also associated with other viewers so that multiple viewers can view the same image, while in other examples, an image is associated with a single viewer.

  At step 1660, the method 1600 includes injecting light into the thin end face 110 of the light wedge 1000, thereby presenting the image to the current viewer. In step 1670, the injection of light into the thin end surface 110 of the optical wedge 100 is stopped. At step 1680, the current viewer number is incremented, and then the method continues to step 1640. Thus, multiple video presentations can be presented to multiple users in parallel. If the refresh rate is high enough, the viewer's eyes may merge the time multiplexed images associated with the viewer into one flicker-free image. A refresh rate higher than 60 Hz is preferred, although the way the viewer feels is different. Processes 1640-1680 loop until all viewers stop watching, and method 1600 may end when all viewers stop watching.

  In some embodiments, it is determined that the user has left the viewing experience (e.g., paid attention over a predetermined period of time) even though the user has stopped viewing the display (e.g., faced differently). Personal audio may continue to be provided until the first time). Similarly, if the user is receiving personal audio via wireless headphones, the personal audio can continue to be provided to the user even when the user leaves the user tracking camera view. This may, for example, make it possible to follow a video presentation while out of the room for a short time.

  In some of the above-described embodiments, the illumination area associated with each eye of each user is projected into a space according to the position of the user detected by a camera such as a depth sensor or a conventional camera, for example. In other embodiments, a single image is projected that can be viewed by both eyes of a single viewer. The relative position of the camera and display can be fixed, but due to mechanical tolerances, there are some differences between where the camera thinks the user is and where the display thinks it is sending light. Can exist. When the display generates sequential lighting in time, look at the lighting projected from the display system onto the viewer's face by looking at the viewer in process using a camera that operates at the frame rate of the display. Can do. This can be used to calibrate the projection. For example, when the left eye image is projected to the viewer, only the left eye should be illuminated by the display. Thus, by matching the eye / head position seen by the camera with the left / right difference images seen sequentially by the same camera, calibration errors can be detected and compensated.

  This extra illumination for each eye may be less than the ambient light. Thus, some invisible (eg, infrared) components may be added to the visible light to increase the detectability of the displayed image. Since the transmittance of a liquid crystal display can be higher in the infrared than in the visible (and in some cases 10 times higher), the additional components can have only a small percentage of the total illumination. And over time, as the user moves around the display, the calibration between the camera and the display can be adaptively refined. As will be appreciated, such infrared illumination can be omitted if the visible light image is sufficiently detectable.

  As will be appreciated, the computing devices described herein may be any suitable computing device configured to execute the programs described herein. For example, the computing device may be a mainframe computer, personal computer, laptop computer, personal digital assistant (PDA), computerized wireless telephone, networked computing device, or other suitable computing device. Also, they can be connected to each other via a computer network such as the Internet. These computing devices typically include a processor and associated volatile and non-volatile memory, and a program stored in the non-volatile memory can be transmitted using portions of the volatile memory and the processor. Configured to run. As used herein, the term “program” means a software or firmware component that can be executed or used by one or more of the computing devices described herein, and that is an individual or group of executable files, data. It is intended to include files, libraries, drivers, scripts, database records, etc. As will be appreciated, a computer readable storage medium may be provided that stores program instructions that are executed by a computing device to cause the computing device to perform the methods described above to cause the operations of the system described above.

  As will be appreciated, the particular configurations and / or approaches described herein with respect to scanning directed light are presented for purposes of illustration, and many variations are possible as these are possible. The specific embodiments or examples should not be construed in a limiting sense. This disclosure includes all new and non-obvious combinations and subcombinations of various processes, systems and configurations described herein, and other features, functions, operations, and / or characteristics, And all equivalents.

Claims (10)

A display surface;
A directional backlight system configured to emit a light beam from the display surface and to change the direction in which the light beam is directed;
A spatial light modulator configured to form an image for display by light from the directional backlight system;
Controlling the first directional backlight system and the spatial light modulator to display a first video content item at a first viewing angle and a second video content item at a second viewing angle A controller configured to, and
A video presentation system.   Controllable by the controller to provide a first personal audio output corresponding to the first video content item and to provide a second personal audio output corresponding to the second video content item. The video presentation system according to claim 1, further comprising a personal audio output unit. The directional backlight system is:
An optical waveguide;
A plurality of light sources arranged along one end face of the optical waveguide, each light source configured to inject light into the end face of the optical waveguide at a different position along the end face of the optical waveguide; The video presentation system of claim 1, comprising a plurality of light sources.   The video presentation system of claim 3, wherein the controller is configured to sequentially brighten two or more of the plurality of light sources to modulate the direction in which the light beam is emitted. The video presentation system further comprises a user tracking camera,
The controller further receives data from the user tracking camera, locates a first viewer and a second viewer via the data, and synchronously modulates the spatial light modulator , Configured to sequentially direct the light beam toward the first viewer and toward the second viewer,
The video presentation system according to claim 1.   The controller is configured to modulate the direction of the light beam in synchronization with the spatial light modulator to generate a stereoscopic image for each of one or more viewers. 4. The video presentation system according to 4.   The controller is configured to detect a change in a position of a first viewer and adjust a direction of the light beam based on the change in the position of the first viewer. Video presentation system. A method for providing different video / audio presentations to different viewers in parallel by a video presentation system having an optical waveguide, a spatial light modulator, and a personal audio output system, the optical waveguide comprising: An end reflector, a second end face opposite to the first end face, a collimating end reflector disposed on the second end face, the first end face and the second end face A display surface extending in between and a back surface opposite to the display surface, the method comprising:
Injecting light into the first end face of the optical waveguide;
Delivering the light to the end reflector via total internal reflection;
The light is internally reflected by the end reflector, thereby collimating the light;
Emitting the light from the display surface;
Changing the position along the first end face of the optical waveguide through which light is injected into the optical waveguide;
In synchronization with changing the position at which light is injected into the light guide, the image generated by the spatial light modulator is switched between a first video content item and a second video content item;
Providing a first audio output corresponding to the first video content item and providing a second audio output corresponding to the second video content item.   Providing the first audio output comprises providing the first audio output to a first wireless headphone set, and providing the second audio output comprises second wireless headphones. 9. The method of claim 8, comprising providing the second audio output to a set. First light injection position based on the position of the first viewer and the position of the second viewer that detects the position of the first viewer and the position of the second viewer via the image data Changing the position at which light is injected into the optical waveguide by changing between the second light injection position and the second light injection position;
The method of claim 8 further comprising:

Images