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EP-3523575-B1 - TRANSPARENT DISPLAY AND METHOD

EP3523575B1EP 3523575 B1EP3523575 B1EP 3523575B1EP-3523575-B1

Inventors

  • FATTAL, DAVID A.

Dates

Publication Date
20260506
Application Date
20171004

Claims (12)

  1. A transparent multiview display (100, 200) comprising: a light guide (110, 21)) configured to guide light along a length of the light guide as guided light (104); a scattering feature (220) being configured to scatter a portion of the guided light out of the light guide as emitted light, wherein the scattering feature is a plurality of multibeam elements (120) spaced apart from one another along the light guide length, a multibeam element of the plurality of multibeam elements being configured to scatter out a portion of the guided light as a plurality of directional light beams (102, 204) having different principal angular directions corresponding to respective different view directions of a multiview image; and an array of light valves (130, 230) configured to modulate the emitted light to provide modulated emitted light (202) representing a displayed image, wherein the transparent display is configured to enable a background scene (101, 201) to be visible through the transparent display, and wherein an area of the multibeam element of the plurality of multibeam elements is between fifty percent and two hundred percent of an area of a light valve of the array of light valves.
  2. The transparent multiview display of Claim 1, wherein the multibeam element comprises a diffraction grating configured to diffractively scatter out the portion of the guided light as the plurality of directional light beams
  3. The transparent multiview display of claim 2, wherein the diffraction grating comprises a plurality of sub-gratings.
  4. The transparent multiview display of Claim 1, wherein the multibeam element comprises one or both of a micro-reflective element and a micro-refractive element, the micro-reflective element being configured to reflectively scatter out a portion of the guided light, the micro-refractive element being configured to refractively scatter out a portion of the guided light.
  5. The transparent multiview display of Claim 1, wherein the multibeam element is located one of at a first surface (110') and at a second surface (110") of the light guide, the multibeam element being configured to scatter out the guided light portion through the first surface.
  6. The transparent multiview display of Claim 1, further comprising a light source (140, 240) optically coupled to an input of the light guide, the light source being configured to provide the guided light one or both of having a non-zero propagation angle and being collimated according to a predetermined collimation factor.
  7. The transparent multiview display of Claim 1, wherein the plurality of multibeam elements are further configured to emit light (206) in a direction of the background scene, the emitted light being configured to illuminate the background scene.
  8. The transparent multiview display of Claim 1, wherein the array of light valves is adjacent to a first surface (110') of the light guide opposite to a second surface (110") adjacent to the background scene, the scattering feature being configured to scatter another portion of the guided light out of the light guide through the second surface to illuminate the background scene.
  9. The transparent multiview display of Claim 6, wherein the light source is configured to provide the light having a predetermined polarization, the scattering feature being configured to provide polarization-preserving scattering and the emitted light having a polarization configured to match an input polarization of the array of light valves.
  10. The transparent multiview display of Claim 6 wherein the light source further comprises a collimator configured to provide the guided light as collimated guided light having a predetermined collimation factor, the scattering feature comprising an angle-preserving scatterer configured to provide angle-preserving scattering according to the collimation factor.
  11. A method of transparent display operation, the method comprising: guiding light along a length of a light guide as guided light (310); scattering a portion of the guided light out of the light guide as emitted light using a scattering feature of the light guide (320), wherein the scattering feature comprises a plurality of multibeam elements, the displayed image being a multiview image and the emitted light comprising a plurality of directional light beams having different principal angular directions corresponding to respective different view directions of the multiview image; and modulating the emitted light using a transparent array of light valves configured to modulate the emitted light as a displayed image (330), wherein a combination of the light guide with the scattering feature and the transparent light valve array of the transparent display enable a background scene to be visible through the transparent display, and wherein an area of the multibeam element of the plurality of multibeam elements is between fifty percent and two hundred percent of an area of a light valve of the array of light valves.
  12. The method of transparent display operation of Claim 11, further comprising scattering another portion of the guided light in a direction to provide illumination to the background scene.

Description

CROSS-REFERENCE TO RELATED APPLICATIONS This application claims priority to U. S. Provisional Patent Application Serial No. 62/404,747, filed October 5, 2016. BACKGROUND Electronic displays are a nearly ubiquitous medium for communicating information to users of a wide variety of devices and products. Most commonly employed electronic displays include the cathode ray tube (CRT), plasma display panels (PDP), liquid crystal displays (LCD), electroluminescent displays (EL), organic light emitting diode (OLED) and active matrix OLEDs (AMOLED) displays, electrophoretic displays (EP) and various displays that employ electromechanical or electrofluidic light modulation (e.g., digital micromirror devices, electrowetting displays, etc.). Generally, electronic displays may be categorized as either active displays (i.e., displays that emit light) or passive displays (i.e., displays that modulate light provided by another source). Among the most obvious examples of active displays are CRTs, PDPs and OLEDs/AMOLEDs. Displays that are typically classified as passive when considering emitted light are LCDs and EP displays. Passive displays, while often exhibiting attractive performance characteristics including, but not limited to, inherently low power consumption, may find somewhat limited use in many practical applications given the lack of an ability to emit light. To overcome the limitations of passive displays associated with emitted light, many passive displays are coupled to an external light source. The coupled light source may allow these otherwise passive displays to emit light and function substantially as an active display. Examples of such coupled light sources are backlights. A backlight may serve as a source of light (often a panel backlight) that is placed behind an otherwise passive display to illuminate the passive display. For example, a backlight may be coupled to an LCD or an EP display. The backlight emits light that passes through the LCD or the EP display. The light emitted is modulated by the LCD or the EP display and the modulated light is then emitted, in turn, from the LCD or the EP display. Often backlights are configured to emit white light. Color filters are then used to transform the white light into various colors used in the display. The color filters may be placed at an output of the LCD or the EP display (less common) or between the backlight and the LCD or the EP display, for example. WO 2016/122679 describes electronic displays which provide different 3-D views and employ an array of multibeam diffraction gratings arranged in offset rows and light valves having color filters. US 2012/0008067 describes a backlight unit and a display device that includes light sources and a light guide plate, with the light sources controlled to emit light in exit directions. US 2015/0003106 describes an extended area lighting device that includes a light guide and surface features disposed on a major surface of the light guide which define indicia. BRIEF DESCRIPTION OF THE DRAWINGS Various features of examples and embodiments in accordance with the principles described herein may be more readily understood with reference to the following detailed description taken in conjunction with the accompanying drawings, where like reference numerals designate like structural elements, and in which: Figure 1A illustrates a perspective view of a multiview display in an example, according to an embodiment consistent with the principles described herein.Figure 1B illustrates a graphical representation of angular components of a light beam having a particular principal angular direction corresponding to a view direction of a multiview display in an example, according to an embodiment consistent with the principles described herein.Figure 2 illustrates a cross sectional view of a diffraction grating in an example, according to an embodiment consistent with the principles described herein.Figure 3A illustrates a cross sectional view of a transparent multiview display in an example, according to an embodiment consistent with the principles described herein.Figure 3B illustrates a plan view of a transparent multiview display in an example, according to an embodiment consistent with the principles described herein.Figure 3C illustrates a perspective view of a transparent multiview display in an example, according to an embodiment consistent with the principles described herein.Figure 3D illustrates another perspective view of a transparent multiview display in an example, according to an embodiment consistent with the principles described herein.Figure 4A illustrates a cross sectional view of a portion of a transparent multiview display including a multibeam element in an example, according to an embodiment consistent with the principles described herein.Figure 4B illustrates a cross sectional view of a portion of a transparent multiview display including a multibeam element in an example, according to another embodiment c