Patent Description:
<CIT> discloses a display with RGBW sub-pixels wherein the blue sub-pixel has a lower luminous intensity and in night mode, the white sub-pixel is disabled in order to improve the colour saturation.

According to the invention, there is provided a system as defined by claim <NUM>.

Also provided is a method as defined by claim <NUM>.

Broadly, embodiments of the inventive concepts disclosed herein are directed to a method and a system including a display element, wherein the display element includes a plurality of pixel groups such that each pixel group has a sub-pixel that has a maximum brightness that is dimmer than a maximum brightness of each of other sub-pixels of the pixel group. Some embodiments may be useful for high dynamic luminance range displays and for augmented reality (AR), virtual reality (VR), and/or mixed reality (MR) systems and displays.

Some embodiments may provide an optimized sub-pixel color architecture for improved MTF for night vision imaging performance in day mode and/or night mode for display elements (e.g., AR display elements and/or VR display elements).

Some embodiments may include a quad red, green, blue, white sub-pixel display with the white sub-pixel optimized for night mode applications, such as presenting digital night vision sensor imagery at the highest MTF possible. Some embodiments may include a quad red, green, blue, green sub-pixel display with the second green sub-pixel optimized for night mode applications, such as presenting digital night vision sensor imagery at the highest MTF possible. Some embodiments may overcome the difficulty in driving solid-state lighting/displays to extremely low levels as the solid-state lighting/displays start to become unstable. Some embodiments may allow for a highest contrast display of white imagery along with an increased MTF of displayed sensor imagery to a user. In some embodiments, benefits may include creating a display with a constant white point across all brightness levels in night mode as well as a consistent gamma correction at the lowest luminance levels.

Some embodiments may include a sub-pixel architecture optimized to provide a best night time/low luminance display performance for a grayscale (e.g., white grayscale or green grayscale) display image. For example, such sub-pixel architecture may provide: consistent gamma and color coordinate over a high dynamic luminance range (e.g., <NUM>,<NUM> foot Lamberts (fL) down to <NUM> fL (<NUM>,<NUM>:<NUM>)) (<NUM> cd/m<NUM> down to <NUM> cd/m<NUM>); maximized MTF performance by utilizing sub-pixel resolutions; and/or best possible rendering of sensor video inputs. In some embodiments, the sub-pixel architecture for a color display may be optimized to provide a highest brightness display possible during day mode while still providing an ability to generate a white image for night vision scenery at a best possible MTF (resolution) and lowest brightness possible. Some embodiments may include a video drive scheme for minimizing bandwidth required for the sub-pixel architecture.

Typically, displays (e.g., AR displays) for head wearable devices (HWDs) (e.g., HMDs and near-eye displays) and head-up displays (HUDs) require very bright displays in order to be seen against sunlit outdoor environments such as a white cloud, blue sky or even the ground. Typically, these displays need to be able to operate in extremely dark environments, which can necessitate the need of a high dynamic brightness range (e.g., <NUM>,<NUM>:<NUM>) for the displays. In some cases, improved display image performance may be required in a low ambient luminance; for example, if the display has a red green blue (RGB) sub-pixel arrangement, the display may require the entire pixel (e.g., the red, green, and blue sub-pixels) to be illuminated to display white imagery with no gain in imaging performance. Typical aerospace applications use green as the primary color for displays in order to make the image easier to see by the human eye, due to the sensitivity of the eye being centered on the green portion of the visible light spectrum. There is a desire to use white for many nighttime/night vision applications, but at low luminance levels it can be hard to control the device for a consistent and uniform display. Sensor systems that input video imagery into an AR display in low ambient conditions can require the display to be driven at very low brightness levels while still being able to accurately represent the sensor inputs. Furthermore, additional sub-pixels may increase video bandwidth required to drive the display.

Currently, common sub-pixel architectures are RGB stripes and red green blue green (RGBG) checkerboards. However, these currently implemented arrangements do not lend themselves to being able to drive a smaller pixel for night operations and still achieve a small color pixel (e.g., a white or green sub-pixel) for a given resolution display. Currently, achieving color balance at low brightness levels poses a significant challenge due to the inability to control solid state lighting at such low levels. Currently, achieving a consistent gamma at low luminance levels for white poses a significant challenge due to the inability to control solid state lighting at such low levels. Currently, increases in subpixels increases required video bandwidth.

Some embodiments may include a display element having a plurality of pixel groups such that each pixel group has a sub-pixel that has a maximum brightness that is dimmer than a maximum brightness of each of other sub-pixels of the pixel group. For example, the dimmer sub-pixel may be a white sub-pixel of a red green blue white (RGBW) or a red green blue green white (RGBGW) sub-pixel architecture. The white sub-pixel may have multiple benefits for operating a display in night mode (e.g., for night vision video). For example, the white sub-pixel may allow for maintaining white balance over a brightness range without the need to for color balancing, which would be necessary with an RGB sub-pixel architecture. For example, the white sub-pixel may allow for simplified gamma correction as gamma correction may only be required for the white channel (as long as video is only displayed in white). For example, the white sub-pixel may allow for <<NUM>% pixel active area to be on, which may simplify brightness control at minimum night luminance settings; for example, controlling of dimming at low end for current implementations can be difficult for organic light-emitting diode (OLED) and active-matrix liquid-crystal display (AMLCD)/light-emitting diode (LED) technology without relying on subpixel drive. For example, the white sub-pixel may allow for a luminance increase of monochrome colors by driving the white sub-pixel with the red, green, and blue sub-pixels to provide RGB plus white (RGB+W) video, such that color may be less saturated with increased brightness. For example, the white sub-pixel may allow for improved night mode MTF performance in both horizontal and vertical axes. For example, the white sub-pixel may allow for a reduction in video bandwidth required for a white display since only one subpixel would be driven, as compared to driving three sub-pixels to display white color for an RGB arrangement. According to an embodiment of the invention, the dimmer sub-pixel is a second green sub-pixel of a red green blue green (RGBG) sub-pixel architecture.

Typically, meeting a brightness requirement for night vision scenes down to <NUM> fL can be a challenge for OLED and LED displays. Typically, each sub-pixel has diode characteristics and requires a forward biased voltage to begin to illuminate the display. Typically, there is too small of a margin between the forward bias and the actual voltage required to illuminate the display at very low light levels. This can result in the use of additional sub-pixel drive schemes such as pulse width modulation (PWM) that can create complexity in the design.

Some embodiments take advantage of the dimmer subpixel (e.g., a dimmer white or green sub-pixel) to improve night vision video scenes. For example, to meet a low light video scene requirement, the dimmer sub-pixel may have less efficiency than other sub-pixels of a pixel group. Reducing the efficiency of the dimmer sub-pixel may increase the margin between the forward bias voltage and the voltage required for the first shade of gray (SOG) (e.g., <NUM> ftL (<NUM> cd/m<NUM>)). This may result in a more stable design with less complexity. For example, some embodiments may reduce the efficiency of the dimmer sub-pixel such that when driven just above the minimum drive voltage, the output may fall below threshold brightness requirement (e.g., a <NUM> fL (<NUM> cd/m<NUM>)). For example, this may provide a larger voltage gap between the forward bias and minimum drive voltages and may simplify control of pixel brightness.

Some embodiments may provide a sub-pixel that has a maximum brightness that is dimmer than a maximum brightness of each of other sub-pixels of the pixel group by including any of various means of reducing the luminous efficacy of the dimmer sub-pixel (e.g., a white or green sub-pixel) as compared to the luminous efficacy of the other sub-pixels of a pixel group. Luminous efficacy is the ratio of luminous flux to electrical input power with units of Lumens per Watt. For example, dimming the dimmer sub-pixel may be achieved by: reducing an emitter area of the dimmer sub-pixel to smaller than the dimmer sub-pixel area; applying a mask layer to the dimmer sub-pixel to partially block light; applying a filter (e.g., an organic filter or an inorganic filter) material, which may be polarization sensitive or insensitive, to attenuate light; reducing the effective size of a drive transistor in the dimmer sub-pixel; adding absorbing particles, such as phosphor or quantum dots, to the emitting surface of the dimmer sub-pixel to reduce overall transmission of light; and/or treating the emitting surface of the dimmer sub-pixel, such as to form microstructures, to prevent light from exiting. For example, by reducing the brightness of the dimmer sub-pixel, additional margin may be created between the forward bias voltage and drive voltage. This margin may allow the system to generate sufficient shades of gray (SOG) (e.g., <NUM> SOG) to the eye under low luminance conditions. In some embodiments, the dimmer sub-pixel may be able to achieve a minimum luminance level of <NUM> fL (<NUM> cd/m<NUM>).

Referring now to <FIG>, an exemplary embodiment of a system <NUM> according to the inventive concepts disclosed herein is depicted. The system <NUM> may be implemented as any suitable system, such as a vehicle (e.g., an aircraft (e.g., an airplane and/or helicopter), a watercraft, a submersible craft, an automobile, or a train), a wearable system, and/or a work station. For example, as shown in <FIG>, the system <NUM> may include at least one head wearable device (e.g., HMD <NUM>, an AR headset, or a near-eye display (e.g., <NUM> as shown in <FIG>)); while some embodiments may include the HMD <NUM>, other embodiments may include one or more elements of the HMD <NUM> implemented without the HMD <NUM> or in another device. In some embodiments, the HMD <NUM> may include at least one eye tracking system <NUM>, at least one head tracking system <NUM>, at least one night vision sensor <NUM>, at least one processor <NUM>, at least one optical system <NUM>, and at least one visor <NUM>, some or all of which may be communicatively coupled at any given time.

The HMD <NUM> may be implemented as any suitable HMD in any suitable environment. For example, as shown in <FIG>, the HMD <NUM> may be implemented as a lightweight, wide field of view (FOV), off-the-visor HMD with an integrated night vision system that may provide a user with unparalleled and intuitive access to flight, navigation, tactical, and/or sensor information that may, for example, be displayed on the visor <NUM>.

The eye tracking system <NUM> may include at least one infrared light source <NUM> (e.g., at least one infrared light emitting diode (LED)), at least one infrared image sensor <NUM>, at least one processor <NUM>, and at least one memory <NUM>, as well as other components, equipment, and/or devices commonly included in an eye tracking system, some or all of which may be communicatively coupled at any time, as shown in <FIG>. The eye tracking system <NUM> may be configured to track eye gestures, track movement of a user's eye, track a user's gaze, and/or otherwise receive inputs from a user's eyes. The eye tracking system <NUM> may be configured for performing fully automatic eye tracking operations of users in real time.

The infrared light source <NUM> may be configured to emit infrared light onto an environment onto at least one eye of a user.

The infrared sensitive image sensor <NUM> may be configured to capture images of the environment illuminated by the infrared light source <NUM>.

The processor <NUM> may be configured to process data received from the infrared sensitive image sensor <NUM> and output processed data to one or more devices or systems of the HMD <NUM> and/or the system <NUM>. For example, the processor <NUM> may be configured to generate eye tracking data and output the generated eye tracking data to one of the devices (e.g., the processor <NUM>) of the HMD <NUM> and/or the system <NUM>. The processor <NUM> may be configured to run various software applications or computer code stored (e.g., maintained) in a non-transitory computer-readable medium (e.g., memory <NUM>) and configured to execute various instructions or operations. The processor <NUM> may be implemented as a special purpose processor configured to execute instructions for performing (e.g., collectively performing if more than one processor) any or all of the operations disclosed throughout. For example, the processor <NUM> may be configured to: receive image data from the infrared sensitive image sensor <NUM>; track movement of at least one eye of a user based on the image data; and/or output eye tracking system data indicative of the tracked movement of the at least one eye of the user. For example, the processor <NUM> may be configured to: perform visor distortion correction operations; perform eye mapping and alignment operations; output, via at least one data connection, eye tracking system data (e.g., indicative of eye azimuth and/or elevation) to an aircraft interface, simulator interface, and/or other computing device of the system; and/or perform a head tracking translation operation.

The head tracking system <NUM> may have optical, magnetic, and/or inertial tracking capability. The head tracking system <NUM> may include at least one sensor <NUM>, at least one processor <NUM>, and at least one memory <NUM>, as well as other components, equipment, and/or devices commonly included in a head tracking system, some or all of which may be communicatively coupled at any time, as shown in <FIG>. The at least one sensor <NUM> may be at least one optical sensor (e.g., an optical infrared sensor configured to detect infrared light), at least one magnetic sensor, and/or at least one inertial sensor. The head tracking system <NUM> may be configured to determine and track a position and an orientation of a user's head relative to an environment. The head tracking system <NUM> may be configured for performing fully automatic head tracking operations in real time. The processor <NUM> of the head tracking system <NUM> may be configured to process data received from the sensors <NUM> and output processed data to one of the computing devices of the system and/or the processor <NUM> for use in generating images aligned with the user's field of view, such as augmented reality or virtual reality images aligned with the user's field of view to be displayed by the optical system <NUM> onto the visor <NUM>. For example, the processor <NUM> may be configured to determine and track a position and orientation of a user's head relative to an environment. Additionally, for example, the processor <NUM> may be configured to generate position and orientation data associated with such determined information and output the generated position and orientation data. The processor <NUM> may be configured to run various software applications or computer code stored in a non-transitory computer-readable medium (e.g., memory <NUM>) and configured to execute various instructions or operations. The at least one processor <NUM> may be implemented as a special purpose processor configured to execute instructions for performing (e.g., collectively performing if more than one processor) any or all of the operations disclosed throughout.

The night vision image sensor <NUM> (e.g., a night vision camera) may be configured to capture night vision images of the environment. In some embodiments, the night vision image sensor <NUM> may be configured to detect infrared light. In some embodiments, the night vision image sensor <NUM> may be configured to output night vision image data to the processor <NUM>, which may output the images to the optical system <NUM> to be displayed onto the visor <NUM>.

The at least one processor <NUM> may be implemented as any suitable processor(s), such as at least one general purpose, at least one image processor, at least one graphics processing unit (GPU), and/or at least one special purpose processor, configured to execute instructions for performing (e.g., collectively performing if more than one processor) any or all of the operations disclosed throughout. In some embodiments, the processor <NUM> may be communicatively coupled to the display element <NUM>. For example, the processor <NUM> may be configured to: receive the eye tracking system data; receive the head tracking system data; receive the night vision image data; generate and/or output synthetic vision system image data to the optical system <NUM>, for example, based on the eye tracking system data and/or the head tracking system data; generate and/or output night vision image data to the optical system <NUM>, for example, based on the eye tracking system data and/or the head tracking system data; generate and/or output augmented reality and/or virtual reality image data to the optical system, for example, based on the eye tracking system data and/or the head tracking system data; and/or generate and/or output other image data, which may include vehicle operation (e.g., flight) information, navigation information, tactical information, and/or sensor information to the optical system <NUM>, for example, based on the eye tracking system data and/or the head tracking system data.

The optical system <NUM> may be configured to receive image data from the processor <NUM> and project images onto the visor <NUM> for display to the user. The optical system <NUM> may include at least one display element <NUM>. While the display element <NUM> is exemplarily depicted and described as being part of the optical system <NUM>, in some embodiments, the display element <NUM> may be used in other display applications that do not include a optical system. In some embodiments, the optical system <NUM> may take the display element <NUM> as an input and transfer, translates, and/or form an image to the correct size and/or orientation for the user to view the information. In some embodiments, the optical system <NUM> may include at least one lens, at least one mirror, diffraction gratings, at least one polarization sensitive component, at least one beam splitter, at least one combiner, at least one waveguide, at least one light pipe, at least one window, and/or the display element <NUM>. For example, the optical system <NUM> may include a collimator. For example, the optical system <NUM> may include a relay lens. For example, the optical system <NUM> may include a collimator and a combiner (e.g. a flat combiner). For example, the optical system <NUM> may include a relay lens and a combiner (e.g., a curved combiner). For example, the optical system <NUM> may include a prism collimator and a beam splitter. For example, the optical system <NUM> may include collimator and a waveguide (e.g., a diffractive, mirror, or beam splitter based waveguide).

In some embodiments, the display element <NUM> may be an emissive display element, such as an OLED or micro-LED display element. In some embodiments that are not part of the invention, the display element <NUM> may include red, green, blue, and white sub-pixels. In some embodiments, the display element <NUM> may include red, green, and blue sub-pixels, such as in a RGBG sub-pixel architecture. For example, the display element <NUM> may have an RGBW or an RGBGW sub-pixel architecture. The display element <NUM> may be configured to display RGB images and/or video, RGB+W images and/or video, RGB+G images and/or video, and/or grayscale (e.g., white grayscale or green grayscale) images and/or video.

According to an embodiment of the invention, the display element <NUM> includes a plurality of pixel groups <NUM>. As used throughout, a pixel group is a group of sub-pixels. Each of the plurality of pixel groups <NUM> includes four sub-pixels <NUM>, <NUM>, <NUM>, <NUM>. A first sub-pixel <NUM> is configured to output light of a first color; a second sub-pixel <NUM> is configured to output light of a second color; a third sub-pixel <NUM> is configured to output light of a third color; and a fourth sub-pixel <NUM> is configured to output light. The fourth sub-pixel <NUM> has a maximum brightness that is dimmer than a maximum brightness of each of the first sub-pixel <NUM>, the second sub-pixel <NUM>, and the third sub-pixel <NUM>. The fourth sub-pixel <NUM> has a maximum brightness that is at least four times dimmer than a maximum brightness of each of the first sub-pixel <NUM>, the second sub-pixel <NUM>, and the third sub-pixel <NUM>. The fourth sub-pixel <NUM> is a green sub-pixel configured to output green light. The first sub-pixel <NUM> is a red sub-pixel configured to output red light.

The second sub-pixel <NUM> is a green sub-pixel configured to output green light. The third sub-pixel <NUM> is a green sub-pixel configured to output green light.

Additionally, the processor is configured to:
operate in a day mode (e.g., for operating in a high luminance environment) and a night mode (e.g., for operating with night vision video in a low luminance environment). When in the day mode, the at least one processor <NUM> is configured to: receive red green blue (RGB) video, encode the RGB video as grayscale video, and drive some or all of the red, green, and blue pixels <NUM>, <NUM>, <NUM> corresponding to the RGB video and some or all of the fourth sub-pixels <NUM> corresponding to the grayscale video such that enhanced RGB plus grayscale images are displayed by the display element <NUM>. When in the night mode, the at least one processor <NUM> is configured to:
receive night vision grayscale video, and drive some or all of the fourth sub-pixels <NUM> corresponding to the night vision grayscale video such that night vision grayscale images are displayed by the display element <NUM>.

Referring now to <FIG>, an exemplary embodiment of a system according to the inventive concepts disclosed herein is depicted. The system may be implemented as any suitable system, such as a vehicle (e.g., an aircraft (e.g., an airplane and/or helicopter), a watercraft, a submersible craft, an automobile, or a train), a wearable system, and/or a work station. For example, as shown in <FIG>, the system may include at least one near-eye display <NUM>. In some embodiments, the near-eye display <NUM> may include some or all of the elements of the HMD <NUM> of <FIG>, and such elements may function similarly as described with respect to the HMD <NUM> of <FIG>.

Referring now to <FIG>, an exemplary embodiment of a system according to the inventive concepts disclosed herein is depicted. The system may be implemented as any suitable system, such as a vehicle (e.g., an aircraft (e.g., an airplane and/or helicopter), a watercraft, a submersible craft, an automobile, or a train), a wearable system, and/or a work station. For example, as shown in <FIG>, the system may include at least one HUD <NUM>. In some embodiments, the HUD <NUM> may include some or all of the elements of the HMD <NUM> of <FIG>, and such elements may function similarly as described with respect to the HMD <NUM> of <FIG>.

Referring now to <FIG>, exemplary embodiments of the display element <NUM> according to the inventive concepts disclosed herein are depicted. For example, the display element <NUM> may have any suitable sub-pixel architecture.

As shown in <FIG>, the display element <NUM> may have a tiled four sub-pixel architecture. For example, each pixel group <NUM> may include red, green, blue, and white sub-pixels <NUM>, <NUM>, <NUM>, <NUM>. In some embodiments, such an architecture may allow for a small white sub-pixel <NUM>. In some embodiments, such an architecture may allow low luminance applications (e.g., night vision video applications) needing white to drive just the white sub-pixels <NUM>, which may maximize image performance and MTF performance. In some embodiments, such an architecture may allow for the red, green, blue, and white sub-pixels <NUM>, <NUM>, <NUM>, <NUM> to all be driven to a same size line widths. In some embodiments, such an architecture may allow for reduced video bandwidth for white only display. Additionally, in some embodiments, each pixel group <NUM> may include red, green, blue, and green sub-pixels with the second green sub-pixel dimmer than the other sub-pixels.

As shown in <FIG>, the display element <NUM> may have a tiled four sub-pixel rotated architecture. For example, each pixel group <NUM> may include red, green, blue, and white sub-pixels <NUM>, <NUM>, <NUM>, <NUM>. In some embodiments, such an architecture may allow for a small white sub-pixel <NUM>. In some embodiments, such an architecture may allow low luminance applications (e.g., night vision video applications) needing white to drive just the white sub-pixels <NUM>. In some embodiments, such an architecture may allow for the red, green, blue, and white sub-pixels <NUM>, <NUM>, <NUM>, <NUM> to all be driven to a same size line widths. In some embodiments, such an architecture may allow for reduced video bandwidth for white only display. In some embodiments, such an architecture may allow for increased perceived brightness of primary display colors since adjacent sub-pixels can be driven to make sub-pixels look larger. In some embodiments, such an architecture may reduce effective resolution from a sub-pixel drive standpoint. Additionally, in some embodiments, each pixel group <NUM> may include red, green, blue, and green sub-pixels with the second green sub-pixel dimmer than the other sub-pixels.

As shown in <FIG>, the display element <NUM> may have a tiled five sub-pixel architecture. For example, each pixel group <NUM> may include red, two green, blue, and white sub-pixels <NUM>, <NUM>, <NUM>, <NUM>. In some embodiments, such an architecture may allow for a small white sub-pixel <NUM>. In some embodiments, such an architecture may allow low luminance applications (e.g., night vision video applications) needing white to drive just the white sub-pixels <NUM>. In some embodiments, such an architecture may allow for the red, green, blue, and white sub-pixels <NUM>, <NUM>, <NUM>, <NUM> to all be driven to a same size line widths. In some embodiments, such an architecture may allow for reduced video bandwidth for white only display. In some embodiments, such an architecture may allow for a large monochrome subpixel for maximum pixel brightness for that color, while other color subpixel arrangement allows for those colors to be driven bright. In some embodiments, such an architecture may provide best resolution for green as depicted, such that the central large pixel has the best resolution. In some embodiments, the central large sub-pixel could be reduced in size and corner sub-pixels increased in size.

Referring now to <FIG>, an exemplary embodiment of a portion of the system of <FIG> according to the inventive concepts disclosed herein is depicted. For example, as shown in <FIG>, the HMD <NUM> may include a reduced bandwidth RGB+W architecture. While <FIG> exemplarily disclose an RGB+W architecture, some embodiments may include any suitable RGB plus grayscale (e.g., white grayscale or green grayscale) architecture where the grayscale may be driven by dimmer sub-pixels (e.g., green or white dimmer sub-pixels). Such reduced bandwidth RGB+W architecture may include control logic <NUM>, a video selector/combiner <NUM>, a grayscale detector <NUM>, a grayscale encoder <NUM>, a memory (e.g., a frame buffer <NUM>), and/or the display element <NUM>, some or all of which may be communicatively coupled. In some embodiments, each of the control logic <NUM>, the video selector/combiner <NUM>, the grayscale detector <NUM>, and/or the grayscale encoder <NUM> may be implemented as a portion of the at least one processor <NUM>, and/or the control logic <NUM>, the video selector/combiner <NUM>, the grayscale detector <NUM>, and/or the grayscale encoder <NUM> may be implemented as separate processors of the at least one processor <NUM>.

The control logic <NUM> may be configured to control whether the system, the display element <NUM>, and/or the at least one processor <NUM> operates in a day mode or night mode. The control logic <NUM> may be further configured to control a brightness of the display element <NUM>, such as based on a detected luminance of the environment. The control logic <NUM> may be further configured to control other operations of the system, the display element <NUM>, and/or the at least one processor <NUM>. The control logic <NUM> may be further configured to output control settings to the video selector/combiner <NUM>, the grayscale detector <NUM>, and/or the grayscale encoder <NUM>.

The video selector/combiner <NUM> may be configured to receive one or more video inputs at any given time, such as an RGB video (e.g., synthetic vision system video), AR content video, and/or night vision video, and to receive control settings. The video selector/combiner <NUM> may be further configured to select one or more of the received video inputs such as based on a received control setting from the control logic <NUM>, and if two or video inputs are selected, the video selector/combiner <NUM> may be further configured to combine the video inputs and output the combined video to the grayscale detector <NUM>.

The grayscale detector <NUM> may be configured to, based on control settings, detect grayscale video (e.g., night vision grayscale video used in night mode) and pass the video to the grayscale encoder. In some embodiments, the grayscale detector <NUM> may be further configured to re-encode RGB video to lower pixel resolution depending on a control setting. The grayscale detector <NUM> may output RGB video to the frame buffer <NUM>, which may be passed to the display element <NUM>. In some embodiments, the grayscale detector <NUM> may be configured to detect grayscale (e.g., based on control settings) or simply pass the RGB video to the frame buffer <NUM> without performing grayscale detection (e.g., based on control settings).

The grayscale encoder <NUM> may be configured to convert RGB video to grayscale video to be displayed by the white sub-pixels <NUM>. The grayscale encoder <NUM> may output grayscale video to the frame buffer <NUM>, which may be passed to the display element <NUM>.

The frame buffer <NUM> may receive RGB video and/or grayscale video. If both the RGB video and the grayscale video are received, the display element <NUM> may display enhanced RGB+W video. In some embodiments, based on a control setting, the frame buffer may only receive RGB video or grayscale video to be displayed by the display element <NUM>.

In some embodiments, the architecture of <FIG> may be scaled to add or subtract a total number of sub-pixels as well as any combination of colors.

Referring now to <FIG>, an exemplary embodiment of a portion of the system of <FIG> according to the inventive concepts disclosed herein is depicted. For example, as shown in <FIG>, the HMD <NUM> may include a scalable reduced bandwidth RGB+W architecture. Such architecture may include control logic <NUM>, a video selector/combiner <NUM>, a grayscale detector <NUM>, a grayscale encoder <NUM>, a memory (e.g., a frame buffer <NUM>), receiver/decoder <NUM>, a grayscale detector <NUM>, a grayscale encoder <NUM>, a memory (e.g., a frame buffer <NUM>), and/or the display element <NUM>, some or all of which may be communicatively coupled. In some embodiments, each of the control logic <NUM>, the video selector/combiner <NUM>, the grayscale detector <NUM>, the grayscale encoder <NUM>, the receiver/decoder <NUM>, the grayscale detector <NUM>, and/or the grayscale encoder <NUM> may be implemented as a portion of the at least one processor <NUM>, and/or the control logic <NUM>, the video selector/combiner <NUM>, the grayscale detector <NUM>, the grayscale encoder <NUM>, the receiver/decoder <NUM>, the grayscale detector <NUM>, and/or the grayscale encoder <NUM> may be implemented as separate processors of the at least one processor <NUM>. The elements of <FIG> may be implemented similarly and function similarly to the elements of <FIG>, except that the scalable reduced bandwidth RGB+W architecture of <FIG> is scalable to allow for an optional intermediate video link. The optional intermediate video link may allow for scalability using the same architecture and may add optional control data within the video stream, which may be used to pass control data to a downstream video processor of the at least one processor <NUM>.

Referring now to <FIG>, an exemplary embodiment of a method <NUM> according to the inventive concepts disclosed herein may include one or more of the following steps. Additionally, for example, some embodiments may include performing one more instances of the method <NUM> iteratively, concurrently, and/or sequentially. Additionally, for example, at least some of the steps of the method <NUM> may be performed in parallel and/or concurrently. Additionally, in some embodiments, at least some of the steps of the method <NUM> may be performed non-sequentially.

A step <NUM> may include outputting, by a first sub-pixel of a pixel group of a display element, light of a first color.

A step <NUM> may include outputting, by a second sub-pixel of the pixel group of the display element, light of a second color.

A step <NUM> may include outputting, by a third sub-pixel of the pixel group of the display element, light of a third color.

A step <NUM> may include outputting, by a fourth sub-pixel of the pixel group of the display element, light, wherein the fourth sub-pixel is less bright than each of the first sub-pixel, the second sub-pixel, and the third sub-pixel.

As will be appreciated from the above, embodiments of the inventive concepts disclosed herein may be directed to a method and a system including a display element, wherein the display element includes a plurality of pixel groups such that each pixel group has a sub-pixel that is less efficient than other sub-pixels of the pixel group.

As used throughout and as would be appreciated by those skilled in the art, "at least one non-transitory computer-readable medium" may refer to as at least one non-transitory computer-readable medium (e.g., e.g., at least one computer-readable medium implemented as hardware; e.g., at least one non-transitory processor-readable medium, at least one memory (e.g., at least one nonvolatile memory, at least one volatile memory, or a combination thereof; e.g., at least one random-access memory, at least one flash memory, at least one read-only memory (ROM) (e.g., at least one electrically erasable programmable read-only memory (EEPROM)), at least one on-processor memory (e.g., at least one on-processor cache, at least one on-processor buffer, at least one on-processor flash memory, at least one on-processor EEPROM, or a combination thereof), or a combination thereof), at least one storage device (e.g., at least one hard-disk drive, at least one tape drive, at least one solid-state drive, at least one flash drive, at least one readable and/or writable disk of at least one optical drive configured to read from and/or write to the at least one readable and/or writable disk, or a combination thereof), or a combination thereof).

Claim 1:
A system, comprising:
a display element (<NUM>), comprising:
a plurality of pixel groups (<NUM>), each of the plurality of pixel groups comprising:
a first sub-pixel (<NUM>) configured to output light of a first color;
a second sub-pixel (<NUM>) configured to output light of a second color;
a third sub-pixel (<NUM>) configured to output light of a third color; and
a fourth sub-pixel (<NUM>) configured to output light;
wherein the fourth sub-pixel has a maximum brightness that is at least four times dimmer than a maximum brightness of each of the first sub-pixel, the second sub-pixel, and the third sub-pixel;
wherein the first sub-pixel is a red sub-pixel configured to output red light, wherein the second sub-pixel is a green sub-pixel configured to output green light, wherein the third sub-pixel is a blue sub-pixel configured to output blue light, wherein the fourth sub-pixel is another green sub-pixel configured to output green light;
the system comprising at least one processor (<NUM>) communicatively coupled to the display element and configured to: determine whether to operate in a day mode or a night mode; when in a day mode, the at least one processor is configured to: receive red green blue (RGB) video; encode the RGB video as grayscale video; and drive some or all of the red, green, and blue pixels corresponding to the RGB video and some or all of the fourth sub-pixels corresponding to the grayscale video such that enhanced RGB plus grayscale images are displayed;
and when in the night mode, the at least one processor is further configured to receive night vision grayscale video, and only drive some or all of the fourth sub-pixels corresponding to the night vision grayscale video such that night vision grayscale images are displayed.