GROUPED DEMULTIPLEXING FOR FOVEATED-RESOLUTION DISPLAY
Embodiments relate to a foveated display, in which image data is displayed with a plurality of display regions associated with different image resolutions. The different resolutions are achieved using macropixels corresponding to groupings of native pixels of the display area onto which image data is loaded to concurrently. Macropixels spanning multiple columns of the display are constructed by grouping data lines of the display such that the same image data is written to pixels of different columns concurrently. The data lines receive image data from a signal line via a demultiplexer, where control signals of the demultiplexer to concurrently couple the signal line to multiple data lines, such that image data provided along the signal line is concurrently provided to each of the multiple data lines in parallel, based upon a predetermined grouping of columns of the display device.
This application claims a priority and benefit to U.S. Provisional Patent Application Ser. No. 63/323,966, filed Mar. 25, 2022, and U.S. Provisional Patent Application Ser. No. 63/339,286, filed May 6, 2022, which are hereby incorporated by reference in its entireties.
BACKGROUNDThis disclosure relates to a display device, and specifically to light emitting diode (LED) or OLED (organic LED) related display which can have configurable resolution.
A display device is often used in a virtual reality (VR) or augmented-reality (AR) system as a head-mounted display (HMD) or a near-eye display (NED). To display high resolution images, it is beneficial to increase the number of pixels in the display device and operate the display device with a higher frame rate. However, when there is an increased number of pixels in a display device being operated at a higher frame rate, time allocated for preparing and writing of data to pixels are reduced. In addition, utilization of an increased number of pixels may result in higher charging frequency, increasing power consumption.
SUMMARYIn some aspects, the techniques described herein relate to a display device that includes a display area having a plurality of pixels arranged in a plurality of rows and a plurality of columns. The display device includes a plurality of data lines, each associated with a column of the plurality of columns and configured to provide image data to pixels of the column, and a plurality of demultiplexers, each connected to a respective signal line of a plurality of signal lines from a source driver circuit and to a respective set of data lines of the plurality of data lines. The display device further includes a set of control lines coupled to the plurality of demultiplexers and configured to provide control signals to the plurality of demultiplexers, wherein the control signals are configured to, during one or more row periods of a plurality of rows periods, control each of the plurality of demultiplexers to concurrently couple the respective signal line to multiple data lines of the respective set of data lines, such that image data provided along the respective signal line is concurrently provided to each of the multiple data lines in parallel, based upon a predetermined grouping of columns of the display device.
In some aspects, the techniques described herein relate to a method, including: at a display driver integrated circuit (DDIC) of a display device, receiving data indicating a grouping of columns of the display area, where the display device includes: a display area including a plurality of pixels arranged in a plurality of rows and a plurality of columns; a plurality of data lines, each associated with a column of the plurality of columns and configured to provide image data to pixels of the column; a plurality of demultiplexers, each connected to a respective signal line of a plurality of signal lines from a source driver circuit and to a respective set of data lines of the plurality of data lines; and a set of control lines coupled to the plurality of demultiplexers and configured to provide control signals to the plurality of demultiplexers. The method further includes, at the DDIC, configuring the control signals to, based on the grouping of columns of the display area, to, during one or more row periods of a plurality of rows periods, control each of the plurality of demultiplexers to concurrently couple the respective signal line to multiple data lines of the respective set of data lines, such that image data provided along the respective signal line is concurrently provided to each of the multiple data lines in parallel. The method further includes operating the display by providing the controls signals control signals to the set of control lines of display during each of the plurality of row periods.
The figures depict embodiments of the present disclosure for purposes of illustration only.
DETAILED DESCRIPTIONReference will now be made in detail to embodiments, examples of which are illustrated in the accompanying drawings. In the following detailed description, numerous specific details are set forth in order to provide a thorough understanding of the various described embodiments. However, the described embodiments may be practiced without these specific details. In other instances, well-known methods, procedures, components, circuits, and networks have not been described in detail so as not to unnecessarily obscure aspects of the embodiments.
Embodiments of the invention may include or be implemented in conjunction with an artificial reality system. Artificial reality is a form of reality that has been adjusted in some manner before presentation to a user, which may include, e.g., a virtual reality (VR), an augmented reality (AR), a mixed reality (MR), a hybrid reality, or some combination and/or derivatives thereof. Artificial reality content may include completely generated content or generated content combined with captured (e.g., real-world) content. The artificial reality content may include video, audio, haptic feedback, or some combination thereof, and any of which may be presented in a single channel or in multiple channels (such as stereo video that produces a three-dimensional effect to the viewer). Additionally, in some embodiments, artificial reality may also be associated with applications, products, accessories, services, or some combination thereof, that are used to, e.g., create content in an artificial reality and/or are otherwise used in (e.g., perform activities in) an artificial reality. The artificial reality system that provides the artificial reality content may be implemented on various platforms, including a head-mounted display (HMD) connected to a host computer system, a standalone HMD, a mobile device or computing system, or any other hardware platform capable of providing artificial reality content to one or more viewers.
Figures (
The HMD 100 shown in
The display assembly 210 may direct the image light to the eye 220 through the exit pupil 230. The display assembly 210 may be composed of one or more materials (e.g., plastic, glass, etc.) with one or more refractive indices that effectively decrease the weight and widen a field of view of the HMD 100.
In alternate configurations, the HMD 100 may include one or more optical elements (not shown) between the display assembly 210 and the eye 220. The optical elements may act to, by way of various examples, correct aberrations in image light emitted from the display assembly 210, magnify image light emitted from the display assembly 210, perform some other optical adjustment of image light emitted from the display assembly 210, or combinations thereof. Example optical elements may include an aperture, a Fresnel lens, a convex lens, a concave lens, a filter, or any other suitable optical element that may affect image light.
In some embodiments, the display assembly 210 may include a source assembly to generate image light to present media to a user's eyes. The source assembly may include, e.g., a light source, an optics system, or some combination thereof. In accordance with various embodiments, a source assembly may include a light-emitting diode (LED) such as a micro-LED, an organic light-emitting diode (OLED), or other type of LED. In some embodiments, the source assembly may correspond to other types of displays in which pixels are arranged in rows and columns, and connected to respective gate and data lines, such as a liquid crystal display (LCD).
The waveguide display 300 may include, among other components, a source assembly 310, an output waveguide 320, and a controller 330. For purposes of illustration,
The source assembly 310 generates image light. The source assembly 310 may include a source 340, a light conditioning assembly (e.g., a decoupling element 360), and a scanning mirror assembly 370. The source assembly 310 may generate and output image light 345 to a coupling element 350 of the output waveguide 320.
The source 340 may include a source of light that generates at least a coherent or partially coherent image light 345. The source 340 may emit light in accordance with one or more illumination parameters received from the controller 330. The source 340 may include one or more source elements, including, but not restricted to light emitting diodes, such as micro-OLEDs, as described in detail below with reference to
The output waveguide 320 may be configured as an optical waveguide that outputs image light to an eye 220 of a user. The output waveguide 320 receives the image light 345 through one or more coupling elements 350 and guides the received input image light 345 to one or more decoupling elements 360. In some embodiments, the coupling element 350 couples the image light 345 from the source assembly 310 into the output waveguide 320. The coupling element 350 may be or include a diffraction grating, a holographic grating, some other element that couples the image light 345 into the output waveguide 320, or some combination thereof. For example, in embodiments where the coupling element 350 is a diffraction grating, the pitch of the diffraction grating may be chosen such that total internal reflection occurs, and the image light 345 propagates internally toward the decoupling element 360. For example, the pitch of the diffraction grating may be in the range of approximately 300 nm to approximately 600 nm.
The decoupling element 360 decouples the total internally reflected image light from the output waveguide 320. The decoupling element 360 may be or include a diffraction grating, a holographic grating, some other element that decouples image light out of the output waveguide 320, or some combination thereof. For example, in embodiments where the decoupling element 360 is a diffraction grating, the pitch of the diffraction grating may be chosen to cause incident image light to exit the output waveguide 320. An orientation and position of the image light exiting from the output waveguide 320 may be controlled by changing an orientation and position of the image light 345 entering the coupling element 350.
The output waveguide 320 may be composed of one or more materials that facilitate total internal reflection of the image light 345. The output waveguide 320 may be composed of, for example, silicon, glass, or a polymer, or some combination thereof. The output waveguide 320 may have a relatively small form factor such as for use in a head-mounted display. For example, the output waveguide 320 may be approximately 30 mm wide along an x-dimension, 50 mm long along a y-dimension, and 0.5-1 mm thick along a z-dimension. In some embodiments, the output waveguide 320 may be a planar (2D) optical waveguide.
The controller 330 may be used to control the scanning operations of the source assembly 310. In certain embodiments, the controller 330 may determine scanning instructions for the source assembly 310 based at least on one or more display instructions. Display instructions may include instructions to render one or more images. In some embodiments, display instructions may include an image file (e.g., bitmap). The display instructions may be received from, e.g., a console of a virtual reality system (not shown). Scanning instructions may include instructions used by the source assembly 310 to generate image light 345. The scanning instructions may include, e.g., a type of a source of image light (e.g. monochromatic, polychromatic), a scanning rate, an orientation of scanning mirror assembly 370, and/or one or more illumination parameters, etc. The controller 330 may include a combination of hardware, software, and/or firmware not shown here so as not to obscure other aspects of the disclosure.
According to some embodiments, source 340 may include a light emitting diode (LED), such as an organic light emitting diode (OLED). An organic light-emitting diode (OLED) is a light-emitting diode (LED) having an emissive electroluminescent layer that may include a thin film of an organic compound that emits light in response to an electric current. The organic layer is typically situated between a pair of conductive electrodes. One or both of the electrodes may be transparent.
As will be appreciated, an OLED display can be driven with a passive-matrix (PMOLED) or active-matrix (AMOLED) control scheme. In a PMOLED scheme, each row (and line) in the display may be controlled sequentially, whereas AMOLED control typically uses a thin-film transistor backplane to directly access and switch each individual pixel on or off, which allows for higher resolution and larger display areas.
In other embodiments, the OLED display is embodied as part of a display panel that does not include any waveguide. The OLED display may be a screen that is viewable directly by to the user's eye instead of passing light through a waveguide.
Anode 420 and cathode 480 may include any suitable conductive material(s), such as transparent conductive oxides (TCOs, e.g., indium tin oxide (ITO), zinc oxide (ZnO), and the like). The anode 420 and cathode 480 are configured to inject holes and electrons, respectively, into one or more organic layer(s) within emissive layer 450 during operation of the device.
The hole injection layer 430, which is disposed over the anode 420, receives holes from the anode 420 and is configured to inject the holes deeper into the device, while the adjacent hole transport layer 440 may support the transport of holes to the emissive layer 450. The emissive layer 450 converts electrical energy to light. Emissive layer 450 may include one or more organic molecules, or light-emitting fluorescent dyes or dopants, which may be dispersed in a suitable matrix as known to those skilled in the art.
Blocking layer 460 may improve device function by confining electrons (charge carriers) to the emissive layer 450. Electron transport layer 470 may support the transport of electrons from the cathode 480 to the emissive layer 450.
In some embodiments, the generation of red, green, and blue light (to render full-color images) may include the formation of red, green, and blue OLED sub-pixels in each pixel of the display. Alternatively, the OLED 400 may be adapted to produce white light in each pixel. The white light may be passed through a color filter to produce red, green, and blue sub-pixels.
Any suitable deposition process(es) may be used to form OLED 400. For example, one or more of the layers constituting the OLED may be fabricated using physical vapor deposition (PVD), chemical vapor deposition (CVD), evaporation, spray-coating, spin-coating, atomic layer deposition (ALD), and the like. In further aspects, OLED 400 may be manufactured using a thermal evaporator, a sputtering system, printing, stamping, etc.
According to some embodiments, OLED 400 may be a micro-OLED. A “micro-OLED,” in accordance with various examples, may refer to a particular type of OLED having a small active light emitting area (e.g., less than 2,000 μm2 in some embodiments, less than 20 μm2 or less than 10 μm2 in other embodiments). In some embodiments, the emissive surface of the micro-OLED may have a diameter of less than approximately 2 μm. Such a micro-OLED may also have collimated light output, which may increase the brightness level of light emitted from the small active light emitting area.
In some embodiments, the active display area 530 may have at least one areal dimension (i.e., length or width) greater than approximately 1.3 inches, e.g., approximately 1.4, 1.5, 1.6, 1.7, 1.8, 1.9, 2.0, 2.25, 2.5, 2.75, or 3 inches, including ranges between any of the foregoing values, although larger area displays are contemplated.
Backplane 520 may include a single crystal or polycrystalline silicon layer 523 having a through silicon via 525 for electrically connecting the DDIC 510 with the active display area 530. In some embodiments, active display area 530 may further include a transparent encapsulation layer 534 disposed over an upper emissive surface 533 of active matrix 532, a color filter 536, and cover glass 538.
According to various embodiments, the active display area 530 and underlying backplane 520 may be manufactured separately from, and then later bonded to, DDIC 510, which may simplify formation of the OLED active area, including formation of the active matrix 532, color filter 536, etc.
The DDIC 510 may be directly bonded to a back face of the backplane opposite to active matrix 532. In further embodiments, a chip-on-flex (COF) packaging technology may be used to integrate display element 540 with DDIC 510, optionally via a data selector (i.e., multiplexer) array (not shown) to form OLED display device 500. As used herein, the terms “multiplexer” or “data selector” may, in some examples, refer to a device adapted to combine or select from among plural analog or digital input signals, which are transmitted to a single output. Multiplexers may be used to increase the amount of data that can be communicated within a certain amount of space, time, and bandwidth.
As used herein, “chip-on-flex” (COF) may, in some examples, refer to an assembly technology where a microchip or die, such as an OLED chip, is directly mounted on and electrically connected to a flexible circuit, such as a direct driver circuit. In a COF assembly, the microchip may avoid some of the traditional assembly steps used for individual IC packaging. This may simplify the overall processes of design and manufacture while improving performance and yield.
In accordance with certain embodiments, assembly of the COF may include attaching a die to a flexible substrate, electrically connecting the chip to the flex circuit, and encapsulating the chip and wires, e.g., using an epoxy resin to provide environmental protection. In some embodiments, the adhesive (not shown) used to bond the chip to the flex substrate may be thermally conductive or thermally insulating. In some embodiments, ultrasonic or thermosonic wire bonding techniques may be used to electrically connect the chip to the flex substrate.
The timing controller 610 may be configured to generate timing control signals for the gate driver 635, the source driver circuit 645, and other components in the display element 540. The timing control signals may include one or more clock signals, a vertical synchronization signal, a horizontal synchronization signal, and a start pulse. However, timing control signals provided from the timing controller 610 according to embodiments of the present disclosure are not limited thereto.
The data processing circuit 615 may be configured to receive image data DATA from the MIPI receiver 630 and convert the data format of the image data DATA to generate data signals input to the source driver circuit 645 for displaying images in the active display area 530.
The I/O interface 625 is a circuit that receives control signals from other sources and sends operation signals to the timing controller 610. The control signals may include a reset signal RST to reset the display element 540 and signals according to serial peripheral interface (SPI) or inter-integrated circuit (I2C) protocols for digital data transfer. Based on the received control signals, the I/O interface 625 may process commands from a system on a chip (SoC), a central processing unit (CPU), or other system control chip.
The MIPI receiver 630 may be a MIPI display serial interface (DSI), which may include a high-speed packet-based interface for delivering video data to the pixels in the active display area 530. The MIPI receiver 630 may receive image data DATA and clock signals CLK and provide timing control signals to the timing controller 610 and image data DATA to the data processing circuit 615.
The active display area 530 may include a plurality of pixels arranged into rows and columns with each pixel including a plurality of subpixels (e.g., a red subpixel, a green subpixel, a blue subpixel). Each subpixel may be connected to a gate line GL and a data line DL and driven to emit light according to a data signal received through the connected data line DL when the connected gate line GL provides a gate-on signal to the subpixel.
The backplane 520 may include conductive traces for electrically connecting the pixels in the active display area 530, the gate driver 635, the source driver circuit 645, and the bonding pads 640. The bonding pads 640 are conductive regions on the backplane 520 that are electrically coupled to the signal lines 624 of the DDIC 510 to receive timing control signals from the timing controller 610, and data signals from the source driver circuit 645. The bonding pads 640 are connected to the gate driver 635 and other circuit elements in the backplane 520. In the embodiment illustrated in
The gate driver 635 may be connected to a plurality of gate lines GL and provide gate-on signals to the plurality of gate lines GL at appropriate times. The gate driver 635 includes a plurality of stages, where each stage is connected to a gate line GL that outputs gate-on signals to a row of pixels.
The source driver circuit 645 may receive data signals from the data processing circuit 615 and provide the data signals to the active display area 530 via data lines DL. The source driver circuit 645 may include a plurality of source drivers, each source driver connected to a column of pixels via a data line DL.
Data lines (e.g., DL1 through DL4) are connected to a demultiplexer 716 that is connected to the source driver circuit 645 via the signal line 748 to receive multiplexed pixel data. Although only a single demultiplexer 716 is illustrated in
Pixel data VDATA for programming columns of pixels is time multiplexed by a multiplexer (not shown) and then demultiplexed by demultiplexer 716 so that fewer signal lines (e.g., line 748) may be used between the source driver circuit 645 and the array of pixels. Because each demultiplexer receives pixel data VDATA for programming pixels for its respective set columns of pixels in parallel, an amount of time needed to program all pixels for a particular row n of the display unit (referred to as a row period TROW) may be defined by an amount of time to program the pixels of the row n corresponding to a particular demultiplexer. Although it is beneficial to multiplex the pixel data for more data lines using the multiplexer and the demultiplexer, the settling time associated with a reference voltage for compensating the threshold voltage of driving transistors in the pixels may restrict the extent of multiplexing/demultiplexing.
In some embodiments, each of the pixels 712, 722, 732, and 742 correspond to subpixels associated with a specific color channel. For example, in some embodiments as discussed above, each pixel of the display contains three subpixels corresponding to red, green, and blue color channels. In some embodiments, the pixels 712, 722, 732, and 742 connected to a common demultiplexer 716 correspond to subpixels of different color channels. For example, pixels 712, 722, and 732 may correspond to red, green, and blue subpixels, respectively, for a given column of pixels, while pixels 742 correspond to red subpixels for another column of pixels. In other embodiments, the pixels 712, 722, 732, and 742 connected to a common demultiplexer 716 correspond to subpixels of the same color channel. For example, the pixels 712, 722, 732, and 742 may correspond to red subpixels for different columns of pixels of the display.
The gate lines GLA through GLN provide gate-on signals to pixels from the gate driver 635. In the example of
The display element 540 further includes timing signal lines (not shown) from the gate driver 635 to provide other timing signals. For example, the display element 540 may include horizontal lines carrying timing signals for operating various switches in the pixels, as described below with reference to
The switch SEL controls a connection between the gate terminal of the driving transistor MD and the data line DL. When the gate line GL provides a gate-on signal (e.g., turns low), the switch SEL turns on, connecting the gate of the driving transistor MD to the data line DL and charging the storage capacitor Cst1 based on a voltage difference between the voltage of the pixel data at the data line DL and the high voltage level (ELVDD). When the gate-on signal is turned off in gate line GL, the switch SEL is turned off, disconnecting the gate of the driving transistor MD from the data line DL.
The switch REST enables or disables the current from the driving transistor MD to flow in the OLED. When the switch REST is turned on, current from the driving transistor MD flows through the switch REST to ground (AGND) that has a lower potential than the low voltage level ELVSS. Conversely, when the switch REST is turned off, the current from the driving transistor MD flows in the OLED.
The switch SW is turned on or off to couple a high voltage source ELVDD to a source of the driving transistor MD. Capacitor Cst2 stores a voltage difference between the high voltage source ELVDD and the source of the driving transistor MD when the switch SW is turned off.
In some embodiments, driving transistor MD, the selection switch (SEL), reset switch (RES), and emission switch (SW) are each implemented as P-channel metal-oxide-semiconductor (PMOS) transistors, where gate signals of the selection switch (SEL), reset switch (RES), and emission switch (SW) are controlled by the timing signals provided via the gate driver circuitry of the display. In other embodiments, one or more of these components may be implemented using other types of switches (e.g., an NMOS transistor).
In some embodiments, data is written to each row of pixels of a display panel (e.g., display element 540) of a display device sequentially. For example, in some embodiments, the gate driver 635 includes a pulsing or shifting gate signal (also referred to herein as an “enable pulse”) that travels along a series of shift registers corresponding to the rows of the display panel. The enable pulse may serve as the gate-on signal provided along the gate line connecting a row of pixels, and each row of the display panel is programmed during a time period TRow (also referred to as a gate-on period or a row period) during which the enable pulse is provided to the gate line GL for the row. The frame rate of the display is based on a row period TRow for programming each row of the display panel. In addition, as discussed above, the pixels of each row are grouped based on one or more demultiplexers, where the row period TRow may be based on an amount of time to program the pixels of the row corresponding a particular demultiplexer.
In some embodiments, a display device is configured to group the programming of pixels of multiple rows and/or multiple columns, where the same data value is provided to each pixel of the multiple rows and/or multiple columns simultaneously, resulting in a “virtual pixel” made up of multiple native pixels (also referred to as a “macropixel”). For example, the display device may group native pixels within m columns by n rows (where m and n are integers, and at least one of m or n is greater than 1), where each pixel of the m columns and n rows is driven simultaneously to create an m×n macropixel. As used herein, columns may refer to pixels arranged in a direction parallel to the data lines of the display, while rows may refer to pixels arranged in a direction parallel to the gate lines of the display, even though certain figures may, for illustrative purposes, illustrate data lines extending in horizontal directions and gate lines extending in vertical directions.
In some embodiments, grouping of native pixels into macropixels is performed to reduce an overall effective resolution of the display panel. For example, by grouping 2×2 sets of native pixels into macropixels, the effective resolution of the display is reduced by a factor of 4. In other embodiments, grouping of pixels into macropixels is performed as part of implementing a foveated display, where different regions of the display panel are configured to display image data at different resolutions. For example, in some embodiments, the display device is configured to display image data within a first display region at a native resolution, and image data within one or more additional display regions at lower resolutions, based upon the size of the macropixels within each region. In some embodiments, the locations of each display region within the display are fixed (referred to as fixed foveated rendering, or FFR). In some embodiments, the locations of the display regions of a foveated display panel are configured dynamically based upon a gaze direction of the user (referred to as gaze-tracked foveated rendering, or GFR), e.g., where a region of display around the gaze direction of the user (e.g., centered on a location of the display corresponding to the user's gaze) is configured to display image data at a native resolution, whereas other regions of the display are configured to display image data at lower resolutions.
In some embodiments, by grouping native pixels into macropixels, power consumption of the display device may be reduced. In other embodiments, macropixel grouping is used to reduce increase a refresh rate of the display. In some embodiments, the use of macropixels allows for the use of displays with greater native resolutions than could be otherwise achieved for a given refresh rate. For example, in some embodiments, a display having above a certain native resolution (e.g., 5 k+ native resolution) would not be able to be implemented with a desired refresh rate (e.g., 90 Hz), due to a required minimum charging time needed for each row. However, by implementing a foveated display in which native pixels of the display are grouped into macropixels, the effective resolution of the display is lowered, allowing for use of displays with higher native resolution, while still maintaining a desired refresh rate.
In some embodiments, GPU 910 and DPU 920 perform one or more image processing functions on the received foveated image data 902. For example, where the initial foveated image data 902 comprises multiple layers, the GPU 910 and DPU 920 may perform composite functions 912 on the image data 902 that combines the layers of the image data (e.g., into a single layer). In some embodiments, the DPU 920 performs color aberration compensation (CAC) 914 on the image data, which may be used to compensate for chromatic aberration caused by magnifying lenses used in VR or AR displays. In some embodiments, these functions may be performed on either the GPU 910 or the DPU 920.
The metadata generation module 916 generates metadata 904 associated with the foveated image data 902. In some embodiments, the metadata generation module 916 collects metadata received from the CPU or GPU describing the foveated image data 902. In some embodiments, the generated metadata specifying locations of two or more display regions of the display, an effective resolution and/or macropixel size of each display region, or some combination thereof. In other embodiments, where the display is configured to implement GFR, the metadata may indicate a gaze location, whereupon the DDIC determines the locations of different display regions based on the received gaze location (e.g., a central display region of native resolution centered on the gaze location, one or more peripheral display regions of lower effective resolution outside the central region, etc.). In some embodiments, the image data 902 may be of a native resolution, and the metadata 904 is used by the DDIC to downsample portions of the image data 902 to generate foveated image data. In some embodiments, the metadata generation module 916 generates the metadata in a format that is compatible with display stream compression algorithms such as Display Stream Compression (DSC) or VESA Display Compression-M (VDC-M), in order to facilitate transmission of the metadata from the GPU 910/DPU 920 to the DDIC 930. While
Transmitter 918 encodes the foveated image data 902 and the generated metadata 904 into a stream of packets 906, to be transmitted to the DDIC 930. In some embodiments, the transmitter 918 comprises an encoder that encodes the packets using a compression algorithm, e.g., DSC, VDC-M, etc. In some embodiments, the transmitter 918 encodes portion of the image data 902 and the metadata 904 into common packets. In other embodiments, the transmitter 918 encodes the image data 902 and the metadata 904 into separate packets. In embodiments where dual transmission channels are available, the image data and metadata may be transmitted via separate channels. In other embodiments where only one channel is available, packets of image data and metadata may be multiplexed, or metadata may be embedded as part of the packets of image data.
The DDIC 930 receives the packets 906 comprising the foveated image data 902 and metadata 904 via a receiver 932, which decodes the received packets to retrieve the foveated image data 902 and metadata 904. In some embodiments, the receiver 932 may correspond to the MIPI receiver 630 illustrated in
The DDIC 930 includes an expander circuit (or “expander”) 936 configured synthesize the locations of macropixels to be displayed by the display element 940, based on the received metadata 904, for which to display the foveated image data 902. For example, the expander 936 uses the metadata 904 to determine groupings of rows and columns of the display element 940, to establish macropixels spanning m×n pixels that are concurrently loaded with common image values. In some embodiments, the expander 936 sets grouped demultiplexing parameters for grouping sets of m columns, and control codes for performing grouped gate scanning to group sets of n rows, to establish m×n macropixels. In some embodiments, the metadata 904 may directly indicate numbers of rows and columns to be grouped by the expander 936. In other embodiments, where the metadata 904 does not directly indicate the grouping of rows and columns (such as in cases where the metadata 904 indicates a center of the display in a GFR display), the expander may determine which rows and columns of the display to be grouped based on the metadata 904. In some embodiments, the expander 936 is implemented as part of the data processing circuit 615 illustrated in
In some embodiments, by expanding the foveated image data after it is transmitted to the DDIC 930, the amount of image data needed to be transmitted may be reduced. For example, because the foveated image data is to be displayed using macropixels in which every pixel within the macropixels is loaded with the same image data simultaneously, the foveated image data 902 does not need to indicate pixel values for each native pixel of the display. Instead, the foveated image data 902 may only need to contain pixel data values of each micropixel of the image to be displayed, resulting in a lower number of pixel values that need to be transmitted for each image.
As discussed above, an m×n macropixel may correspond to a grouping of m columns and n rows of the display, such that all pixels in the intersection of the m columns and n rows are programmed with the same image data simultaneously, as if they were a single pixel. In some embodiments, the m columns of the display are grouped using grouped demultiplexing (GDX), which is discussed in greater detail below. The n rows of the display are grouped using grouped gate scanning (GGS), which the gate lines of multiple rows are grouped together, such that data from the data lines of the display is written to the pixels of each of the grouped rows concurrently, resulting in each of the grouped rows receiving the same image data. By grouping different sets of rows and columns at different portions of the display, different display regions having different effective resolutions (e.g., different sized macropixels) can be created.
The number of rows and number of columns that are grouped together can be independently configured in different regions of the display, to create macropixels of different sizes. For example, in a center region 1006, no grouping of rows or columns is performed, such that the effective resolution of the region is the same as the native resolution. However, in region 1008, the foveated display groups sets of two rows together, while columns remain ungrouped, creating 1×2 macropixels in these regions, resulting in an effective resolution that is half that of the native resolution. Similarly, in regions 1010, the foveated display groups sets of two columns and sets of two rows, creating 2×2 macropixels, resulting in the regions having an effective resolution that is ¼ that of the native resolution. This extends outwards to regions 1012, corresponding to corner regions that are farthest away from the center region 1006, in which sets of four rows and sets of four columns are grouped together, resulting in 1/16 effective resolution. In some embodiments, the expander configures the grouping of rows and columns based on the position of each region within the image data, based upon the received metadata. For example, in some embodiments, where column grouping is applied across an entire row, for rows with mixed resolution (e.g., 1×1 pixels and 2×1 pixels), column grouping may be implemented based upon the higher resolution, such that image data for each lower-resolution pixel of the row (comprising a plurality of native pixels spanning multiple columns) is provided over separate time periods, instead of concurrently. As the data provided via the signal line to the data lines is constant over the separate time periods, some power savings relative to programming the higher-resolution pixels of the row may be achieved.
As discussed above, in some embodiments, the data lines of the display are connected to a plurality of demultiplexers (e.g., demultiplexers 716 illustrated in
In accordance with some embodiments, grouping columns of the display using grouped demultiplexing (GDX) comprises configuring the demultiplexers that provide data from the signal lines of the DDIC to the data lines of the display to provide the same data to multiple pixels concurrently. In some embodiments, to facilitate the ability for the same data to be provided to different pixels (e.g., pixels of different columns to be grouped together to form a macropixel), the demultiplexers, instead of being connected to data lines corresponding to different color channels, are configured to be connected to the same color channel for different pixels, such that each demultiplexer is able to provide image data for a particular color channel for a plurality of pixels simultaneously.
By configuring the demultiplexers to be only provide any data for a particular color channel to its connected data lines, each signal line connected to a demultiplexers only provides image data for that particular color channel. This may serve to reduce an amount of power needed to drive the display panel, as changes in image data values for the same color channel of adjacent pixels is typically small, particularly when displaying image content with large areas of flat textures, in comparison to changes in image data values of different color channels. For example, in some embodiments, the power consumption of the display is based on an amount of current used to drive the data lines, which is a function of the toggling frequency of the source driver and data lines, and a voltage difference for each conversion at the source driver and data lines. When each signal line provides data corresponding to a particular color channel for adjacent pixels of the display, the toggling frequency and voltage difference are reduced, lowering power consumption.
By controlling the timing of the control signals DMX1 through DMX6, pixels of adjacent columns can be grouped and concurrently provided with the same image data. For example, to group pairs of pixels on adjacent columns, multiple control signals are provided concurrently, and the demultiplexer 1202 provides the same image data to multiple data lines concurrently. For example, as shown in
As shown in
For embodiments such as that illustrated in
Although
As discussed above, an m×n macropixel (corresponding to a grouping of m columns and n rows of the display) may be created by grouping m columns of pixels using GDX, and grouping n rows of pixels using GGS. In some embodiments, the gate lines of each row of pixels of the display may be configured to pass through an enable pulse that is shifted sequentially between the rows of the display when it is received at the row, or to “skip” the enable pulse when it is received at the row, but instead pass through the enable pulse when it is also passed through by an adjacent row, thus grouping the row with the adjacent row, so that both rows write data from the data lines onto their respective pixels concurrently.
The gate lines 1306 of the display may be grouped to create multi-row macropixels. For example,
As shown in
In some embodiments where the gate select lines of multiple rows are grouped, the demultiplexer 1302 may be used to load signal line data onto the data lines over multiple row periods. For example, as illustrated in
The reduced row period of certain rows increases the overall the refresh rate of the display. In some embodiments, the reduced row period for rows containing grouped pixels (via GDX, GGS, or both) may result in the display having, for a given supply voltage, a higher refresh rate than would otherwise be possible if no pixel grouping was to be performed (e.g., if the display were to display image data entirely using native resolution), due to a minimum amount of time needed to charge the data lines of each demultiplexer individually. Alternatively, in foveated displays in which it is known that at least a certain amount of grouped demultiplexing will be performed to create macropixels, the display may be built with a larger number of rows, while maintaining at least a minimum refresh rate that is higher than what would otherwise be possible if no pixel grouping was to be performed. For example, in embodiments where the display contains a first region displaying using macropixels generated using grouped demultiplexing and a second area with native resolution (e.g., no grouped demultiplexing), reducing a time used to display rows containing pixels grouped using grouped demultiplexing may allow for additional charging time to be allotted to areas of native resolution on the display. This may allow for the display area of the display to include a larger number of rows and have each row be allotted sufficient charging time, without increasing the overall refresh rate of the display.
In some embodiments, the DDIC, when using the metadata to synthesize the locations of macropixels to be displayed by the display, determines a row period duration to allot to each row of the display, based a size of a macropixel to be displayed on the row. For example, in some embodiments, the greater the grouping of data lines using grouped demultiplexing, the greater the row period for a row on which the image data is to be written can be reduced. In addition, the row period may be further reduced based upon the number of rows of the displayed grouped using grouping gate scanning. In some embodiments, the DDIC configures the duration of the row period by configuring the timing of the demultiplexer control signals (e.g., DMX1 through DMX6) and a clock rate controlling the shifting of the enable pulse between rows of the display.
In some embodiments, grouped demultiplexing can be used to reduce power consumption of the display (e.g., by lowering a source bias current used when charging multiple data lines).
In some embodiments, bias current reduction may also be used in conjunction with grouped gate scanning (GGS) to effect power consumption savings.
While
The GPU/DPU receives 1710 image data to be displayed on the display in a foveated manner. In some embodiments, the image data comprises foveated image data containing image data associated with different display regions having different resolutions. For example, in some embodiments the image data includes at least image data within a first region at a first resolution (e.g., a native resolution) and image data within a second region at a second, lower resolution.
The GPU/DPU generates 1720 metadata based upon the received image data indicative of locations of different display regions associated with different resolutions. In some embodiments, the metadata locations of two or more display regions of the display, an effective resolution and/or macropixel size of each display region, or some combination thereof. In other embodiments, the metadata may indicate a gaze location on the display.
The GPU/DPU transmits 1730 the received image data and the generated metadata the DDIC. In some embodiments, the GPU/DPU compresses the image data and the metadata using one or more display stream compression algorithms such as DSC or VDC-M to generate a stream of one or more packets, and transmits the packets to the DDIC
The DDIC receives 1740 the image data and generated metadata from the GPU/DPU. In some embodiments, the DDIC receives the image data and metadata in the form of a stream of encoded packets, whereupon the DDIC decodes the packets to extract the image data and metadata
The DDIC synthesizes 1750 locations of macropixels to be displayed by the display, based on the received metadata. In some embodiments, an expander module of the DDIC uses the metadata to determine which rows and columns of the display are to be grouped using grouped demultiplexing and grouped gate selection, to establish macropixels spanning m×n pixels that are concurrently loaded with common image values at specific locations on the display. In some embodiments, the metadata may directly indicate numbers of rows and columns to be grouped by the expander module. In other embodiments, where the metadata does not directly indicate the grouping of rows and columns, the expander module infers which rows and columns of the display should be grouped based on the metadata.
The DDIC configures 1760 control signals for performing grouping of rows and columns of the display, based on the synthesized macropixel locations. In some embodiments, the expander module of the DDIC sets grouped demultiplexing parameters for grouping sets of m columns, and control parameters for performing grouped gate scanning to group sets of n rows, and the timing at which these parameters are provided, to establish m×n macropixels. In some embodiments, the DDIC may further configure a row period duration and/or a source driver bias current based on the macropixel locations, e.g., to increase a refresh rate and/or reduce a power consumption of the display when writing data to pixels of rows where grouped demultiplexing and/or grouped gate scanning is performed.
The DDIC operates 1770 the display by providing the control signals to the display in accordance with a determined timing. In some embodiments, demultiplexer control signals provided to the demultiplexers allow each demultiplexer to provide signal line data to multiple data lines concurrently, grouping pixels on multiple adjacent data lines. In addition, control parameters provided to gate control circuits of rows of the display are used to selectively group the gate lines of adjacent rows together, so that a gate selection signal is provided all gate lines of the group during the same row period (e.g., when the enable pulse is received at a last row of the group). The combination of selectively grouping pixels of different columns and pixels of different rows is used to establish macropixels that span multiple columns and rows.
The DDIC receives 1810 data indicating a grouping of pixels columns for displaying image data on the pixels of a display. In some embodiments, the data corresponds to metadata associated with received foveated image data. In some embodiments, the data is determined based on the received metadata. In some embodiments, the data indicates different groupings of columns corresponding to different row periods. For example, the display may be configured to group pixels of adjacent columns into first sets (e.g., two-column groups) over a first set of row periods, and into second sets (e.g., three-column groups) over a second set of row periods.
The DDIC sets 1820 demultiplexer control signals based on the grouping of columns as indicated by the received data. In some embodiments, the DDIC configures the control signals for each of a plurality of row periods, based upon how columns are to be grouped during each row period, which is based on which rows of the display are to contain grouped pixels of adjacent columns. For example, during row periods without grouping, the control signals are set to cause the demultiplexers to provide signal line data to each data line sequentially. On the other hand, during row periods in which grouping is to be performed, the control signals are set to cause the demultiplexers to provide signal line data concurrently to multiple data lines (e.g., sets of two, three, or six data lines concurrently).
The DDIC optionally 1830 configures a duration of one or more row periods, based a level of demultiplexer grouping to be performed during the row period. In some embodiments, the DDIC is configured to reduce a duration of a row period, based upon a time constant for concurrently charging a number data lines based upon the level demultiplexer grouping. As the time constant of charging does not scale linearly, this allows the grouped data lines to fully charge while reducing extraneous time during which the data lines are fully charged. This may serve to increase a refresh rate of the display, but reducing the duration allotted to writing to the pixels of certain rows. In addition, in some embodiments, the DDIC may further reduce a duration of a row period based upon whether the row is grouped with other rows using grouped gate selection.
The DDIC optionally 1840 configures a source bias current to be provided to the signal lines during one or more row periods, based a level of demultiplexer grouping to be performed during the row period. In some embodiments, the DDIC is configured to reduce the source bias current to be provided to the signal lines during a row period, based upon the time constant for concurrently charging a number data lines based upon the level demultiplexer grouping. As the time constant of charging does not scale linearly, this allows the grouped data lines to fully charge within the row period, while reducing overall power consumption of the display. In addition, in some embodiments, the DDIC may further reduce the source bias current based upon whether the row is grouped with other rows using grouped gate selection.
The DDIC operates 1850 the display by providing the demultiplexer control signals to the demultiplexers of the display during each row period. As the enable pulse shifts between rows of the display in accordance with the configured row period durations, the demultiplexer control signals configure which pixels of adjacent columns are grouped when writing data to pixels of the row (and any other rows grouped with the current row). By grouping pixels in this manner, macropixels spanning multiple columns are formed, and used for rendering areas of lower resolution in a foveated display. In combination with grouped rows, m×n macropixels can be formed, allowing for fine control of the effective resolution of different display regions.
The language used in the specification has been principally selected for readability and instructional purposes, and it may not have been selected to delineate or circumscribe the inventive subject matter. It is therefore intended that the scope of the disclosure be limited not by this detailed description, but rather by any claims that issue on an application based hereon. Accordingly, the disclosure of the embodiments is intended to be illustrative, but not limiting, of the scope of the disclosure, which is set forth in the following claims.
Claims
1. A display device comprising:
- a display area comprising a plurality of pixels arranged in a plurality of rows and a plurality of columns;
- a plurality of data lines, each associated with a column of the plurality of columns and configured to provide image data to pixels of the column;
- a plurality of demultiplexers, each connected to a respective signal line of a plurality of signal lines from a source driver circuit and to a respective set of data lines of the plurality of data lines;
- a set of control lines coupled to the plurality of demultiplexers and configured to provide control signals to the plurality of demultiplexers, wherein the control signals are configured to, during one or more row periods of a plurality of rows periods, control each of the plurality of demultiplexers to concurrently couple the respective signal line to multiple data lines of the respective set of data lines, such that image data provided along the respective signal line is concurrently provided to each of the multiple data lines in parallel, based upon a predetermined grouping of columns of the display device.
2. The display device of claim 1, wherein:
- each data line of the plurality of data lines corresponds to a color channel,
- each of the plurality of signal lines is configured to provide image data of a single color channel, and
- each respective set of data lines consists of data lines corresponding to a single color channel.
3. The display device of claim 2, wherein each respective set of data lines is associated with a respective set of adjacent columns of the plurality of columns.
4. The display device of claim 1, wherein the control signals are configured to, during each of the plurality of row periods, control each of the plurality of demultiplexers to couple the respective signal line to each data line of the respective set of data lines for a predetermined charging period.
5. The display device of claim 4, wherein a duration of the predetermined charging period is, during the one or more row periods, based upon a number of the multiple data lines concurrently coupled to the respective signal line.
6. The display device of claim 5, wherein a bias current of the source driver circuit is, during the one or more row periods, configured based upon the number of the multiple data lines concurrently coupled to the respective signal line.
7. The display device of claim 5, wherein a length of a row period during the one or more row periods is shortened relative to one or more other row periods of the plurality of row periods, based on the number of the multiple data lines concurrently coupled to the respective signal line.
8. The display device of claim 7, wherein the length of the row period is shortened based upon a time constant of concurrently charging the multiple data lines.
9. The display device of claim 1, wherein each row comprises a respective gate line configured to provide a gate enable signal to pixels of the row, and further comprising:
- a plurality of gate scan driver circuits, each coupled to a gate line of a respective row of the plurality of rows, and to a gate scan line configured to sequentially provide an enable pulse to gate scan driver circuits of the plurality of gate scan driver circuits over a plurality of time periods, and configured to selectively provide the enable pulse provided by the gate scan line or a gate enable signal of a gate line of an adjacent row of the plurality of rows as a gate enable signal to the gate line of the respective row, based upon a predetermined grouping of rows of the display device.
10. The display device of claim 9, wherein:
- each of the plurality of gate scan driver circuits is connected to one or more gate control lines of a plurality of gate control lines configured to provide a gate scanning signal based on the predetermined grouping of rows of the display device, and
- wherein each gate scan driver circuit is each configured to selectively provide the enable pulse or the gate enable signal of the gate line of the adjacent row as the gate enable signal for the respective row based on the gate scanning signal.
11. The display device of claim 9, wherein a timing of the plurality of row periods is based upon a timing at which the enable pulse is provided by a gate scan line sequentially to gate scan driver circuits of the plurality of rows of the display device.
12. The display device of claim 1, wherein the one or more row periods of a plurality of rows periods is based upon which rows of the plurality of rows contain groupings of pixels of adjacent columns, in accordance with the predetermined grouping of columns of the display device.
13. A method, comprising:
- at a display driver integrated circuit (DDIC) of a display device, receiving data indicating a grouping of columns of the display area, where the display device comprises: a display area comprising a plurality of pixels arranged in a plurality of rows and a plurality of columns; a plurality of data lines, each associated with a column of the plurality of columns and configured to provide image data to pixels of the column; a plurality of demultiplexers, each connected to a respective signal line of a plurality of signal lines from a source driver circuit and to a respective set of data lines of the plurality of data lines; and a set of control lines coupled to the plurality of demultiplexers and configured to provide control signals to the plurality of demultiplexers;
- at the DDIC, configuring the control signals to, based on the grouping of columns of the display area, to, during one or more row periods of a plurality of rows periods, control each of the plurality of demultiplexers to concurrently couple the respective signal line to multiple data lines of the respective set of data lines, such that image data provided along the respective signal line is concurrently provided to each of the multiple data lines in parallel;
- operating the display by providing the controls signals control signals to the set of control lines of display during each of the plurality of row periods.
14. The method of claim 13, further comprising, at the DDIC, configuring a duration of each of the one or more row periods based upon a number of the multiple data lines concurrently coupled to the respective signal line during the row period.
15. The method of claim 14, wherein the duration of each of the one or more row periods is configured based upon a time constant of charging the multiple data lines concurrently coupled to the respective signal line during the row period.
16. The method of claim 13, further comprising, at the DDIC, configuring a bias current of the source driver circuit during the each of the one or more row periods based upon the number of the multiple data lines concurrently coupled to the respective signal line during the row period.
17. The method of claim 13, wherein:
- each data line of the plurality of data lines corresponds to a color channel,
- each of the plurality of signal lines is configured to provide image data of a single color channel,
- each respective set of data lines consists of data lines corresponding to a single color channel, and
- each respective set of data lines is associated with a respective set of adjacent columns of the plurality of columns.
17. (canceled)
18. The method of claim 13, further comprising configuring the control signals to, during each of the plurality of row periods, control each of the plurality of demultiplexers to couple the respective signal line to each data line of the respective set of data lines for a predetermined charging period, wherein a length of the predetermined charging period is, during the one or more row periods, based upon a number of the multiple data lines concurrently coupled to the respective signal line.
19. The method of claim 13, wherein each row of the display device comprises a respective gate line configured to provide a gate enable signal to pixels of the row, and the display devices further comprises a plurality of gate scan driver circuits, each coupled to a gate line of a respective row of the plurality of rows, and to a gate scan line configured to sequentially provide an enable pulse to gate scan driver circuits of the plurality of gate scan driver circuits over a plurality of time periods, and configured to selectively provide the enable pulse provided by the gate scan line or a gate enable signal of a gate line of an adjacent row of the plurality of rows as a gate enable signal to the gate line of the respective row, based upon a predetermined grouping of rows of the display device.
20. The method of claim 19, further comprising, at the DDIC, configuring a duration of each of the one or more row periods by configuring a timing at which the enable pulse is provided by the gate scan line sequentially to gate scan driver circuits of the plurality of rows of the display device.
Type: Application
Filed: Mar 24, 2023
Publication Date: Sep 28, 2023
Inventors: Yongman Lee (Sunnyvale, CA), Qianqian Wang (Santa Clara, CA)
Application Number: 18/126,190