Stacked display panels for image enhancement

A head-mounted display (HMD) includes an electronic display element and an optics block. The electronic display element includes a plurality of display panels that together output image light. The plurality of panels including a first display panel and a second display panel. The first display panel includes a first plurality of sub-pixels that are separated from each other by a non-emission area. The second panel includes a second plurality of sub-pixels. The second display panel is positioned offset from the first display panel such that the second plurality of sub-pixels emit light through the non-emission area of the first display panel. The optics block configured to direct the image light to an exit pupil of the HMD corresponding to a location of an eye of a user of the HMD.

BACKGROUND

The present disclosure generally relates to enhancing images from electronic displays, and specifically to using stacked display panels for image enhancement.

Electronic displays include a plurality of pixels, which may each include a plurality of sub-pixels (e.g., a red sub-pixel, a green sub-pixel, etc.). Arrangement of individual sub-pixels may affect the appearance and performance of an electronic display device. A sub-pixel includes both an emission area and a non-emission area, and the fill factor of the sub-pixel describes the ratio of light emission area versus total area of the sub-pixel. The non-emission areas thus limit the fill factor of each sub-pixel. Additionally, some arrangements of sub-pixels may increase fixed pattern noise under certain conditions. For example, magnification of a pixel may result in non-emission areas between individual sub-pixels of the pixel becoming visible to the user, resulting in a “screen door” pattern (i.e., an increase in fixed pattern noise) in an image presented to a user.

SUMMARY

A stacked electronic display element includes a plurality of display panels that together output image light. The plurality of panels including a first display panel and a second display panel. The first display panel includes a first plurality of sub-pixels that are separated from each other by a non-emission area. The second display panel includes a second plurality of sub-pixels. The second display panel is positioned offset from the first display panel such that the second plurality of sub-pixels emit light through the non-emission area of the first display panel. The stacked electronic display element may be used to, e.g., increase effective fill factor, increase resolution, present high dynamic range images, present three dimensional images, or some combination thereof.

In some embodiments, the stacked electronic display is part of a head-mounted display. The HMD includes an optics block configured to direct the image light to an exit pupil of the HMD corresponding to a location of an eye of a user of the HMD.

DETAILED DESCRIPTION

System Overview

FIG. 1is a block diagram of a virtual reality (VR) system environment100in which a VR console110operates. The system environment100shown byFIG. 1comprises a VR headset105, an imaging device135, and a VR input interface140that are each coupled to the VR console110. WhileFIG. 1shows an example system100including one VR headset105, one imaging device135, and one VR input interface140, in other embodiments any number of these components may be included in the system100. For example, there may be multiple VR headsets105each having an associated VR input interface140and being monitored by one or more imaging devices135, with each VR headset105, VR input interface140, and imaging devices135communicating with the VR console110. In alternative configurations, different and/or additional components may be included in the system environment100.

The VR headset105is a head-mounted display that presents media to a user. Examples of media presented by the VR head set include one or more images, video, audio, or some combination thereof. In some embodiments, audio is presented via an external device (e.g., speakers and/or headphones) that receives audio information from the VR headset105, the VR console110, or both, and presents audio data based on the audio information. An embodiment of the VR headset105is further described below in conjunction withFIGS. 2A and 2B. The VR headset105may comprise one or more rigid bodies, which may be rigidly or non-rigidly coupled to each other together. A rigid coupling between rigid bodies causes the coupled rigid bodies to act as a single rigid entity. In contrast, a non-rigid coupling between rigid bodies allows the rigid bodies to move relative to each other.

The VR headset105includes an electronic display115, an optics block118, one or more locators120, one or more position sensors125, and an inertial measurement unit (IMU)130. The electronic display115displays images to the user in accordance with data received from the VR console110. In various embodiments, the electronic display115may comprise a single stacked electronic display element or multiple stacked electronic display elements (e.g., a stacked electronic display element for each eye of a user).

A stacked electronic display element is a plurality of display panels that together output image light. As discussed in detail below, a stacked electronic display element may be used to enhance images in a plurality of ways (e.g., increase effective fill factor, increase resolution, present high dynamic range images, present three dimensional images, or some combination thereof). The stacked electronic display element includes at least a front display panel and a rear display panel, and in some embodiments may be separated by one or more intermediate components. The front display panel is a transparent electronic display panel. A transparent electronic display panel is partially or fully transparent and may be, for example, a transparent organic light emitting diode display (TOLED), some other transparent electronic display, or some combination thereof. An intermediate component may be a transparent electronic display panel, a film (e.g., attenuator, polarizer, diffractive, spectral, etc.), or some combination thereof. The rear display panel may be, e.g., a liquid crystal display (LCD), an organic light emitting diode (OLED) display, an active-matrix organic light-emitting diode display (AMOLED), a TOLED, some other display, or some combination thereof.

The display panels are stacked such that image light emitted from the rear display panel passes through any intermediate components and the front display toward the optics block118. Likewise any intermediate component that is a transparent electronic display panel emits image light that passes through the front display panel toward the optics block, and may additionally pass through other intermediate components prior entering the front display panel.

Each display panel in a stacked electronic display element includes a display area comprising a plurality of sub-pixels (e.g., transparent OLED (TOLED)), where a sub-pixel is a discrete light emitting component that is positioned in the emission layer. For example, a sub-pixel emits red light, yellow light, blue light, green light, white light, or any other suitable color of light. A sub-pixel includes both an emission area, and a non-emission area, and a fill factor of the sub-pixel describes the ratio of light emission area versus total area of the sub-pixel.

It is desirable to have a high fill factor as it reduces fixed pattern noise in a display area. The display area is a portion of the electronic display panel that is presented to the viewing user. As shown below with reference toFIG. 4A, the emission area is an area of the sub-pixel which emits light. The non-emission area is an area of the sub-pixel which does not emit light, and generally includes transistors, electrodes, etc., which belong to the structure of an electronic display panel and are not active emitters of light. Different sub-pixels are separated from each other by the non-emission areas (also referred to as dark spaces) of adjacent sub-pixels.

In some embodiments, the display panels in the stacked electronic display element are positioned such that there is no, negligible, or minimal overlap between emissions areas of different display panels. For example, the emission areas of a first electronic display panel that emits image light into an input surface of a second electronic display panel backfills some, or all of, the non-emission areas of the second electronic display panel with light emitted from the first electronic display panel. Accordingly, an effective area of emitted light relative to the total area of the sub-pixel is increased. This increases an effective fill factor of the stacked electronic display element and thereby reduces the screen door effect. An effective fill factor is a fill factor based on the aggregate emissions areas and non-emission areas of the electronic display panels in the stacked electronic display element. Accordingly, in the above manner, a stacked electronic display element results in a higher fill factor than conventional electronic displays, as discussed in detail below with regard toFIGS. 4A and 4B.

Moreover, in some embodiments, the stacked electronic display element has a higher resolution than a single electronic display element. For example, different signals may be provided to each of the electronic display panels in the stacked electronic display element in order to produce an aggregate image that has a higher resolution than an image produced by a single electronic display panel. An aggregate image is an image composed of image light emitted from different electronic display elements in the stacked electronic display element.

In some embodiments, the stacked electronic display element is configured to emit high dynamic range (HDR) images. The stacked electronic display element may be configured such that each electronic display panel within the stacked electronic display element outputs image light at different dynamic ranges, such that an aggregate image emitted by the stacked electronic display panel is a high dynamic range (HDR) image. For example, the front electronic display panel may be configured to drive the higher dynamic range of an image and the rear electronic display panel could drive the lower dynamic range of the image, resulting in an aggregate image that is an HDR image. Accordingly, in the above manner, a stacked electronic display may be configured to operate as a HDR display, as discussed in detail below with regard toFIGS. 5A and 5B.

In some embodiments, the stacked electronic display element is configured to emit three dimensional (3D) images. A typical electronic display emits images in two dimensions (e.g., x and y components in a Cartesian coordinate system), however, in contrast a 3D image also includes depth (e.g., a z component). The stacked electronic display element segments a total depth of a 3D image into different regions and assigns each segment to a different electronic display panel within the stacked electronic display element. As the electronic display elements are located at different positions in the stacked electronic display element, and emit image light corresponding to their assigned segment, the aggregate image emitted by the stacked electronic display element is a 3D image. Accordingly, in the above manner, a stacked electronic display may be configured to operate as a 3D display, as discussed in detail below with regard toFIGS. 6A-6C.

In some embodiments, images projected by the electronic display115are rendered on the sub-pixel level. This is distinct from, say an RGB (red-green-blue) layout, which has discrete red, green, and blue pixels (red, green, and blue) and each pixel in the RGB layout includes a red sub-pixel, which is adjacent to a green sub-pixel that is adjacent to a blue sub-pixel. The red, green, and blue sub-pixels operate together to form different colors. In an RGB layout a sub-pixel in a pixel is restricted to working within that pixel. However, in some embodiments, sub-pixels in the electronic display operate within multiple “logical” pixels in their surrounding vicinity to form different colors. The sub-pixels are arranged on the display area of the electronic display115in a sub-pixel array. Examples of a sub-pixel array include PENTILE® RGBG, PENTILE® RGBW, some another suitable arrangement of sub-pixels that renders images at the sub-pixel level.

The optics block118magnifies received light from the electronic display115, corrects optical errors associated with the image light, and the corrected image light is presented to a user of the VR headset105. An optical element may be an aperture, a Fresnel lens, a convex lens, a concave lens, a filter, or any other suitable optical element that affects the image light emitted from the electronic display115. Moreover, the optics block118may include combinations of different optical elements. In some embodiments, one or more of the optical elements in the optics block118may have one or more coatings, such as anti-reflective coatings.

Magnification of the image light by the optics block118allows the electronic display115to be physically smaller, weigh less, and consume less power than larger displays. Additionally, magnification may increase a field of view of the displayed media. For example, the field of view of the displayed media is such that the displayed media is presented using almost all (e.g., 110 degrees diagonal), and in some cases all, of the user's field of view. Magnification of the image light may cause an increase in fixed pattern noise, also referred to as the “screen door effect,” which is a visual artifact where dark space separating pixels and/or sub-pixels of a display become visible to a user in an image presented by the display. However, as noted above, the stacked electronic display element in the electronic display115may be configured to such that electronic display panels backfill the dark spaces (non-emission areas) of other electronic display panels, thus reducing the screen door effect. In some embodiments, the dark spaces can effectively be reduced to zero. In some embodiments, the optics block118is designed so its effective focal length is larger than the spacing to the electronic display115, which magnifies the image light projected by the electronic display115. Additionally, in some embodiments, the amount of magnification may be adjusted by adding or removing optical elements.

The optics block118may be designed to correct one or more types of optical error. Examples of optical error include: two dimensional optical errors, three dimensional optical errors, or some combination thereof. Two dimensional errors are optical aberrations that occur in two dimensions. Example types of two dimensional errors include: barrel distortion, pincushion distortion, longitudinal chromatic aberration, transverse chromatic aberration, or any other type of two-dimensional optical error. Three dimensional errors are optical errors that occur in three dimensions. Example types of three dimensional errors include spherical aberration, comatic aberration, field curvature, astigmatism, or any other type of three-dimensional optical error. In some embodiments, content provided to the electronic display115for display is pre-distorted, and the optics block118corrects the distortion when it receives image light from the electronic display115generated based on the content.

The locators120are objects located in specific positions on the VR headset105relative to one another and relative to a specific reference point on the VR headset105. A locator120may be a light emitting diode (LED), a corner cube reflector, a reflective marker, a type of light source that contrasts with an environment in which the VR headset105operates, or some combination thereof. In embodiments where the locators120are active (i.e., an LED or other type of light emitting device), the locators120may emit light in the visible band (˜380 nm to 750 nm), in the infrared (IR) band (˜750 nm to 1 mm), in the ultraviolet band (10 nm to 380 nm), some other portion of the electromagnetic spectrum, or some combination thereof.

In some embodiments, the locators120are located beneath an outer surface of the VR headset105, which is transparent to the wavelengths of light emitted or reflected by the locators120or is thin enough not to substantially attenuate the wavelengths of light emitted or reflected by the locators120. Additionally, in some embodiments, the outer surface or other portions of the VR headset105are opaque in the visible band of wavelengths of light. Thus, the locators120may emit light in the IR band under an outer surface that is transparent in the IR band but opaque in the visible band.

The IMU130is an electronic device that generates fast calibration data based on measurement signals received from one or more of the position sensors125. A position sensor125generates one or more measurement signals in response to motion of the VR headset105. Examples of position sensors125include: one or more accelerometers, one or more gyroscopes, one or more magnetometers, another suitable type of sensor that detects motion, a type of sensor used for error correction of the IMU130, or some combination thereof. The position sensors125may be located external to the IMU130, internal to the IMU130, or some combination thereof.

Based on the one or more measurement signals from one or more position sensors125, the IMU130generates fast calibration data indicating an estimated position of the VR headset105relative to an initial position of the VR headset105. For example, the position sensors125include multiple accelerometers to measure translational motion (forward/back, up/down, left/right) and multiple gyroscopes to measure rotational motion (e.g., pitch, yaw, roll). In some embodiments, the IMU130rapidly samples the measurement signals and calculates the estimated position of the VR headset105from the sampled data. For example, the IMU130integrates the measurement signals received from the accelerometers over time to estimate a velocity vector and integrates the velocity vector over time to determine an estimated position of a reference point on the VR headset105. Alternatively, the IMU130provides the sampled measurement signals to the VR console110, which determines the fast calibration data. The reference point is a point that may be used to describe the position of the VR headset105. While the reference point may generally be defined as a point in space; however, in practice the reference point is defined as a point within the VR headset105(e.g., a center of the IMU130).

The IMU130receives one or more calibration parameters from the VR console110. As further discussed below, the one or more calibration parameters are used to maintain tracking of the VR headset105. Based on a received calibration parameter, the IMU130may adjust one or more IMU parameters (e.g., sample rate). In some embodiments, certain calibration parameters cause the IMU130to update an initial position of the reference point so it corresponds to a next calibrated position of the reference point. Updating the initial position of the reference point as the next calibrated position of the reference point helps reduce accumulated error associated with the determined estimated position. The accumulated error, also referred to as drift error, causes the estimated position of the reference point to “drift” away from the actual position of the reference point over time.

The imaging device135generates slow calibration data in accordance with calibration parameters received from the VR console110. Slow calibration data includes one or more images showing observed positions of the locators120that are detectable by the imaging device135. The imaging device135may include one or more cameras, one or more video cameras, any other device capable of capturing images including one or more of the locators120, or some combination thereof. Additionally, the imaging device135may include one or more filters (e.g., used to increase signal to noise ratio). The imaging device135is configured to detect light emitted or reflected from locators120in a field of view of the imaging device135. In embodiments where the locators120include passive elements (e.g., a retroreflector), the imaging device135may include a light source that illuminates some or all of the locators120, which retro-reflect the light towards the light source in the imaging device135. Slow calibration data is communicated from the imaging device135to the VR console110, and the imaging device135receives one or more calibration parameters from the VR console110to adjust one or more imaging parameters (e.g., focal length, focus, frame rate, ISO, sensor temperature, shutter speed, aperture, etc.).

The VR input interface140is a device that allows a user to send action requests to the VR console110. An action request is a request to perform a particular action. For example, an action request may be to start or end an application or to perform a particular action within the application. The VR input interface140may include one or more input devices. Example input devices include: a keyboard, a mouse, a game controller, or any other suitable device for receiving action requests and communicating the received action requests to the VR console110. An action request received by the VR input interface140is communicated to the VR console110, which performs an action corresponding to the action request. In some embodiments, the VR input interface140may provide haptic feedback to the user in accordance with instructions received from the VR console110. For example, haptic feedback is provided when an action request is received, or the VR console110communicates instructions to the VR input interface140causing the VR input interface140to generate haptic feedback when the VR console110performs an action.

The VR console110provides media to the VR headset105for presentation to the user in accordance with information received from one or more of: the imaging device135, the VR headset105, and the VR input interface140. In the example shown inFIG. 1, the VR console110includes an application store145, a tracking module150, and a virtual reality (VR) engine155. Some embodiments of the VR console110have different modules than those described in conjunction withFIG. 1. Similarly, the functions further described below may be distributed among components of the VR console110in a different manner than is described here.

The application store145stores one or more applications for execution by the VR console110. An application is a group of instructions, that when executed by a processor, generates content for presentation to the user. Content generated by an application may be in response to inputs received from the user via movement of the HR headset105or the VR interface device140. Examples of applications include: gaming applications, conferencing applications, video playback application, or other suitable applications.

The tracking module150calibrates the VR system100using one or more calibration parameters and may adjust one or more calibration parameters to reduce error in determination of the position of the VR headset105. For example, the tracking module150adjusts the focus of the imaging device135to obtain a more accurate position for observed locators on the VR headset105. Moreover, calibration performed by the tracking module150also accounts for information received from the IMU130. Additionally, if tracking of the VR headset105is lost (e.g., the imaging device135loses line of sight of at least a threshold number of the locators120), the tracking module140re-calibrates some or all of the system environment100.

The tracking module150tracks movements of the VR headset105using slow calibration information from the imaging device135. The tracking module150determines positions of a reference point of the VR headset105using observed locators from the slow calibration information and a model of the VR headset105. The tracking module150also determines positions of a reference point of the VR headset105using position information from the fast calibration information. Additionally, in some embodiments, the tracking module150may use portions of the fast calibration information, the slow calibration information, or some combination thereof, to predict a future location of the headset105. The tracking module150provides the estimated or predicted future position of the VR headset105to the VR engine155.

The VR engine155executes applications within the system environment100and receives position information, acceleration information, velocity information, predicted future positions, or some combination thereof of the VR headset105from the tracking module150. Based on the received information, the VR engine155determines content to provide to the VR headset105for presentation to the user. For example, if the received information indicates that the user has looked to the left, the VR engine155generates content for the VR headset105that mirrors the user's movement in a virtual environment. Additionally, the VR engine155performs an action within an application executing on the VR console110in response to an action request received from the VR input interface140and provides feedback to the user that the action was performed. The provided feedback may be visual or audible feedback via the VR headset105or haptic feedback via the VR input interface140.

FIG. 2Ais a diagram of a virtual reality (VR) headset, in accordance with an embodiment. The VR headset200is an embodiment of the VR headset105, and includes a front rigid body205and a band210. The front rigid body205includes one or more stacked electronic display elements of the electronic display115(not shown inFIG. 2A), the IMU130, the one or more position sensors125, and the locators120. In the embodiment shown byFIG. 2A, the position sensors125are located within the IMU130, and neither the IMU130nor the position sensors125are visible to the user.

The locators120are located in fixed positions on the front rigid body205relative to one another and relative to a reference point215. In the example ofFIG. 2A, the reference point215is located at the center of the IMU130. Each of the locators120emit light that is detectable by the imaging device135. Locators120, or portions of locators120, are located on a front side220A, a top side220B, a bottom side220C, a right side220D, and a left side220E of the front rigid body205in the example ofFIG. 2A.

FIG. 2Bis a cross section225of the front rigid body205of the embodiment of a VR headset200shown inFIG. 2A. As shown inFIG. 2B, the front rigid body205includes an optical block230that provides altered image light to an exit pupil250. The exit pupil250is the location of the front rigid body205where a user's eye245is positioned. For purposes of illustration,FIG. 2Bshows a cross section225associated with a single eye245, but another optical block, separate from the optical block230, provides altered image light to another eye of the user.

The optical block230includes a stacked electronic display element235of the electronic display115, and the optics block118. The stacked electronic display element235emits image light toward the optics block118. The optics block118magnifies the image light, and in some embodiments, also corrects for one or more additional optical errors (e.g., distortion, astigmatism, etc.). The optics block118directs the image light to the exit pupil250for presentation to the user.

FIG. 3is an example stacked electronic display element300including two display panels, in accordance with an embodiment. In some embodiments, the stacked electronic display element300is part of the electronic display115of the VR headset105(e.g., stacked electronic display element235). In other embodiments it is some other electronic display, e.g., a computer monitor, a television set, etc.

A stacked electronic display element300is a plurality of display panels that together output image light. The stacked electronic display element300includes a front electronic display panel310and a rear electronic display panel320. The front electronic display panel310is a transparent electronic display panel. As discussed above with respect toFIG. 1, a transparent electronic display panel may be, for example, a TOLED, some other transparent electronic display, or some combination thereof. The rear electronic display panel may320may be, e.g., a LCD, an OLED, an AMOLED, a TOLED, some other display, or some combination thereof.

While the stacked electronic display element300includes two electronic display panels, in other embodiments, the stacked electronic display element300includes one or more intermediate components between the front panel310and the rear panel320. An intermediate component may be a transparent electronic display panel, a film (e.g., attenuator, polarizer, diffractive, spectral, etc.), or some combination thereof.

The front electronic display panel310includes an input surface330(also referred to as a mounting surface) and an output surface340(also referred to as a display surface). The rear electronic display panel310includes an output surface360(also referred to as a display surface). The output surfaces340,360each are configured to emit image light. In some embodiments, the image light output by each panel may be a same image light, but have the brightness adjusted to account for attenuation of image light resulting from the image light passing through the front panel310and any intermediate components. In other embodiments, the image light emitted from each electronic display panel may be different from image light emitted from other electronic display panels (e.g., to create aggregate images of increased resolution, high dynamic range, 3-D images, or some combination thereof). In some embodiments, the front electronic display panel310is affixed to the rear electronic display element320. For example, the input surface330of the front electronic display panel310is affixed to the output surface360of the rear electronic display element320using a transparent adhesive. Alternatively the front electronic display panel310may be affixed the rear electronic display element320via a mechanical coupling.

Stacked Electronic Display Element Configured to Increase Fill Factor

FIG. 4Ais an example array400of sub-pixel emission areas on a front electronic display panel (e.g., front electronic display panel310) of a stacked electronic display element (e.g., stacked electronic display element300). In some embodiments, the array400may be part of a stacked electronic display element of some other electronic display, e.g., a computer monitor, a television set, etc. The example array400shown inFIG. 4Aincludes emission areas410,420, and430for respectively, red sub-pixels, blue sub-pixels, and green sub-pixels. The emission areas410,420,430correspond to areas of the sub-pixels that actively emit light toward a viewing user. A non-emission area440separates the emission areas of each sub-pixel from one or more adjacent emission areas of other sub-pixels. The non-emission area440is a portion of the array400that does not emit light, and in conventional electronic displays may become visible to a user under certain circumstances (e.g., magnification), causing the screen door effect that degrades image quality.

FIG. 4Bis an example array450of aggregate sub-pixel emission areas on a stacked electronic display panel (e.g., stacked electronic display element300). In some embodiments, the array450may be part of some other electronic display, e.g., a computer monitor, a television set, etc. The example array450includes image light from the array400of sub-pixel emission areas on a front electronic display panel (e.g., front electronic display panel310), as well as image light from sub-pixel emission areas from a rear electronic display panel (e.g., rear electronic display panel320). The example array450shown inFIG. 4Aincludes emission areas410,420, and430for respectively, red sub-pixels, blue sub-pixels, and green sub-pixels of the front electronic display panel, and emission areas450,460, and470for respectively, red sub-pixels, blue sub-pixels, and green sub-pixels of the rear electronic display panel.

InFIG. 4B, the display panels are stacked such that the emission areas of the front electronic display panel are offset from the emission areas of the rear electronic display panel. The offset is such that image light emitted from the rear display panel passes through the non-emission areas440of the front electronic display to generate the example array450. Accordingly, an effective area of emitted light relative to the total area of the sub-pixels is increased in the stacked electronic display element, and thereby increases an effective fill factor of the stacked electronic display element and reduces the screen door effect. Moreover, in some embodiments, the front electronic display panel and the rear electronic display panel may be configured to emit image light such that the aggregate image has a higher resolution than a single electronic display element.

Stacked Electronic Display Element Configured for High Dynamic Range Operation

Dynamic range describes a ratio between the maximum and minimum light intensities in an image, and may vary from image to image. In practice, it is difficult to achieve the full dynamic range experienced by humans using conventional electronic displays. Electronically reproduced images/video often adjust image data having a wide dynamic range to fit into a narrower recorded dynamic range that can be more easily displayed. For example, a scene showing an interior of a room with a sunlit view outside a window, for instance, will have a relatively high dynamic range (e.g., approximately 100,000:1). However, a typical LCD display has a dynamic range (e.g., commercially referred to as contrast ratio meaning the full-on/full-off luminance ratio) of around 1000:1, accordingly, in some situations the LCD is not able to present the entire dynamic range. Instead, when showing a movie, game, etc., a conventional electronic display is able to show both shadowy nighttime scenes and bright outdoor sunlit scenes, but uses cues to suggest night or day (e.g., a nighttime scene may usually contain duller colors, be lit with blue lighting which reflects the way that the human eye sees colors at low light levels, etc.).

A HDR (High Dynamic Range) image stores pixel values that span a range of light intensities that is greater than a range able to be displayed by a single electronic display element. A stacked electronic display element maybe configured to present a HDR image that is the aggregate of image light emitted from the front electronic display panel, the rear electronic display panel, and any additional display panels. The stacked electronic display element assigns different luminosity ranges to different electronic display panels. For example, the stacked electronic display may divide a total dynamic range of the HDR image into ‘n’ number of reduced dynamic ranges, where ‘n’ corresponds to the number of electronic display panels in the stacked electronic display element. A reduced dynamic range is a dynamic range associated with a single display panel (e.g., 1000:1). The stacked electronic display provides each display panel its respective reduced dynamic range, and they each display panel in the stacked electronic display emits portions of an image in accordance with its associated reduced dynamic range. Accordingly, the dynamic range of the stacked electronic display element scales with the number of electronic display panels within the stacked electronic display. For example, in some embodiments the stacked electronic display may contain three electronic displays, one of which could be configured to present high luminosity portions of an HDR image, another configured to present middle luminosity portions of the HDR image, and the remaining electronic display panel configured to present low luminosity portions of the HDR image.

Additionally, in some embodiments, the stacked electronic display element may include additional intermediate comments between a front electronic display panel and a rear electronic display panel that affect/enhance the image. For example, the stacked electronic display element may include one or more films (e.g., attenuator, polarizer, diffractive, spectral, etc.) between one or more electronic display panels.

FIG. 5is an example array500of aggregate sub-pixel emission areas on a stacked electronic display element (e.g., stacked electronic display element300) configured to operate as an HDR display. In some embodiments, the array500may be part of some other electronic display, e.g., a computer monitor, a television set, etc. The example array500includes image light from an array of sub-pixel emission areas on a high luminosity electronic display panel (e.g., rear electronic display panel320), as well as image light from sub-pixel emission areas from a low luminosity electronic display panel (e.g., front electronic display panel310).

In this example, the stacked electronic display element includes two electronic display panels. One electronic display element presents low luminosity portions of the HDR image, and the other electronic display panel presents high luminosity portions of the HDR image. In this embodiment, high luminosity refers to a portion of the HDR image having a higher luminosity than a low luminosity portion of the HDR image. In some embodiments, the combination of the low luminosity and high luminosity portions of the image describe the luminosity of the entire HDR image.

The example array500shown inFIG. 5includes emission areas510,520, and530for respectively, high luminosity red sub-pixels, high luminosity blue sub-pixels, and high luminosity green sub-pixels of the high luminosity electronic display panel, and emission areas540,550, and560for respectively, low luminosity red sub-pixels, low luminosity blue sub-pixels, and low luminosity green sub-pixels of the rear electronic display panel. Accordingly, the array500is able to present HDR images by effectively doubling the dynamic range that would otherwise be attributed to a single electronic display element.

InFIGS. 4A and 4B and 5, each panel has the same sub-pixel pattern. In alternate embodiments, complimentary sub-pixel patterns may be used on different display panels.

Stacked Electronic Display Element Configured for Presenting 3D Images

In some embodiments, the stacked electronic display element is configured to emit 3D images. As noted above, a typical electronic display emits 2-dimensional images (e.g., ‘x’ and ‘y’ components in a Cartesian coordinate system). In contrast a 3D image also includes depth (e.g., a range of ‘z’ values), which is not present in a 2-D image—where a user simply focuses on a single plane.

In some embodiments, a stacked electronic display element (e.g., stacked electronic display element300) may be configured to present 3D images. For example, the stacked electronic display element may receive image data describing an image object for presentation to a user as a 3D image. The stacked electronic display element determines a total depth of the image object using the image data (e.g., determines a range of ‘z’ that describes the image object). The stacked electronic display element then segments the determined total depth of the image object into ‘n’ different, successive, regions, where ‘n’ is a number of electronic display panels in the stacked electronic display element. The regions are successive in the sense that n1describes a first portion of the image object, n2describes a next portion of the object, and so on for all the regions. For example, if the image object was of an inside of a room that has a total depth of 12 feet and the stacked electronic display element includes 6 electronic display elements, the stacked electronic display element would segment the total depth into 6 successive regions. Each region is associated with a range of depth values. For example, a first region (e.g., n1) may be associated with z1to z2, a second region (e.g., n2) would be associated with z3to z4, and so on, where z4≥z3≥z2≥z1, and the absolute depth describes the size of a region (i.e., |z2−z1|).

In some embodiments, an absolute depth of each region is the same. For example, an absolute depth for each region is the total depth divided by the number of electronic display panels. Continuing the example above, as the total depth is 12 feet and the number of electronic display panels is 6, each region would have an absolute depth of 2 feet (=12/6) at successive positions throughout the total depth of the image object. Alternatively, the absolute depth of one or more of the regions may differ from each other. For example, the stacked electronic display element may segment the image object such that some regions are much larger than others. For example, if the image object is of a room that only includes a flower in the foreground, the stacked electronic display element may segment an image object such that the absolute depth of the regions are smaller over the region describing the flower (i.e., more regions are describing the foreground), and larger for regions describing the background.

The stacked electronic display element assigns the regions to each of the electronic display panels, and the stacked electronic display panels emit image light corresponding, respectively, to their assigned region. Accordingly, each electronic display panel is emitting image light representative of particular slice of the image object over a range of depth values corresponding to its assigned region. Note, because each electronic display panel is emitting image light representative of a single region, energy consumption is generally comparable to energy consumption of a single electronic display panel presenting the entire image object.

As the electronic display panels do not occupy the same location, an aggregate image emitted by the stacked electronic display element has depth (i.e., the aggregate image being a 3-D image). A user could then focus throughout the 3D image rather than on a single image plane as would be typical in a conventional 2D display. Additionally, in some embodiments, the spacing between the electronic display panels may be increased to, e.g., better emphasize differences in depth between light emitted from different electronic display panels. For example, glass thicknesses may be increased on one or more of the electronic display elements, film thicknesses between electronic display panels increased, etc. Additionally, in some embodiments, a user may elect to have the stacked electronic display element present a “flat” 2D image. A difference from conventional 2D displays is that the stacked electronic display element may display an image using different panels—which can be used to increase the viewing comfort of a viewing user. For example, a viewing user watching a movie may instruct the stacked electronic display element to adjust the distance that the image appears from the viewing user to increase their viewing comfort of the movie.

FIG. 6Ais a perspective view of an example an image object600, according to an embodiment. The image object600is representative of an opaque 3D object to be presented by a stacked electronic display element. The image object600includes a cross section610which represents a slice in y-z plane of the image object600.FIG. 6Bis a cross section620of the image object600inFIG. 6A, according to an embodiment.

FIG. 6Cis a diagram625including a stacked electronic display element630configured to operate as a 3D display, according to an embodiment. In some embodiments, the stacked electronic display element630is part of the electronic display115of the VR headset105(e.g., stacked electronic display element235). In other embodiments it is some other electronic display, e.g., a computer monitor, a television set, etc.

In this example, the stacked electronic element630includes six electronic display panels, specifically, electronic display panels660A,660B,660C,660D,660E, and660F. In some embodiments, the spacing between one or more of the electronic display panels660may vary to help emphasize a difference in depth in image light emitted from different electronic display panels660. The stacked electronic display element630segments the image object600into 6 different segments. In this embodiment, each of regions has a same absolute depth.

Each of the electronic display panels660A,660B,660C,660D,660E, and660F emit image light corresponding to their assigned region. For example, the electronic display panel660F emits image light representative of a top portion670and bottom portion675of the image object600, accordingly the electronic display panel660F does not present portions of the image object600that are assigned to different region (e.g., a tip680of the image object600that is emitted by the electronic display panel660A). This partial usage of each electronic display element660helps minimize power consumption—such that total power consumption is comparable to a single electronic display element660presenting the entire image object660.

The stacked electronic display element630is positioned inside a focus point635of the optics block118. The optics block118has an effective focal length which is positive, accordingly, the stacked electronic stacked electronic display element630positioned inside the focus point635results in an aggregate image665that is virtual, erect, and appears farther away from an eye245of a user than the electronic display element630. Note, as drawn inFIG. 6C, the portion of the image object600shown in the aggregate image655corresponds to the cross section610shown inFIGS. 6A, and 6B. However, this is merely an cross section of the total image, and if illustrated in its entirety the aggregate image655is a 3-D image of the image object600.

Additional Configuration Information