Facebook Technologies, LLC

Meta Platforms Technologies, LLC

Pixtronix, Incorporated

Ilias Pappas

William Thomas Blank

Michael Yee

Yu-Hsuan Li

Ramakrishna Chilukuri

Sean Lord

Edward Buckley

Warren Andrew Hunt

Mark A Horowitz

Daniel Henry Morris

William Padraic Henry

Fahri Yaras

Sharvil Shailesh Talati

Alexander Victor Henzen

Salman Mazhar

Electronic display devices include digital and analog control of pixel intensity. A digital pixel control circuit and an analog pixel control circuit are provided within each pixel. The digital pixel control circuit employs digital PWM techniques to control a number of subframes within each frame during which a driving current is supplied to a light emitting element within the pixel. The analog pixel control circuit controls the level of the driving current supplied to the light emitting element within the pixel during the frame. In one example, the digital pixel control circuit and the analog pixel control circuit may together control pixel intensity with the analog pixel control circuit providing additional in-pixel bits for increased color depth. Alternatively, the digital pixel control circuit may control pixel intensity and the analog pixel control circuit may control non-uniformity compensation.

Artificial reality systems including digital and analog control of pixel intensity

Described is a display system comprising a light source, a scanning assembly, and a controller. The light source includes a first plurality of emitters forming a column that emits a first color. The light source also includes a second plurality of emitters forming a column that emits a different color. The scanning assembly includes a reflective surface rotated by the controller using a control signal having a nonlinear, pulsed waveform. The controller drives the first plurality of emitters and the second plurality of emitters in sequence, during respective portions of the nonlinear waveform, and in synchronization with rotation of the reflective surface such that light emitted by the first plurality of emitters and the second plurality of emitters is reflected onto a same pixel of an output image. The controller also adjusts emission durations of individual emitters to compensate for changes in the rotational speed of the reflective surface.

Control scheme for a scanning display

An active matrix display where in one embodiment each cell comprises: a driving circuit for providing current to light emitting devices placed in the cell under the control of a data driver signal, a first light emitting device location connected to the driving circuit and a second light emitting device location connected in series to the first light emitting device location. A first thin-film transistor (TFT) is connected in parallel with the first light emitting device location and a second TFT is connected in parallel with the second light emitting device location, its gate node connected to the gate node of the first TFT. One terminal of a third TFT is connected to the gate nodes of the first and second TFTs and selectively connects a control signal to the first and second TFTs under the control of a scan driver signal. The control signal determines which of a first or second light emitting device placed in the cell emits light when the driving circuit provides current.

Display with redundant light emitting devices

A display device includes a silicon wafer including digital circuits, a micro-light emitting diode (micro-LED) wafer including an array of micro-LEDs, and an indium-gallium-zinc-oxide (IGZO) layer between the silicon wafer and the micro-LED wafer and including analog circuits. The digital circuits are characterized by a first operating supply voltage and are configured to generate digital control signals based on digital display data of an image frame. The analog circuits are characterized by a second operating supply voltage higher than the first operating supply voltage. The analog circuits includes analog storage devices configured to storing analog signals, and transistors controlled by the digital control signals and the analog signals to generate drive currents for driving the array of micro-LEDs. The digital circuits on the silicon wafer or the analog circuits in the IGZO layer include level-shifting circuits at interfaces between the digital circuits and the analog circuits.

Hybrid IGZO pixel architecture

Techniques are described for operating a display system comprising a light source, a scanning assembly, and a controller. The light source includes a plurality of emitters arranged in a column. The scanning assembly includes a reflective surface. A control signal including linear or sinusoidal pulses is applied to cause the reflective surface to rotate. The controller drives the emitters in sequence, using a same image data value, and in synchronization with the rotating of the reflective surface such that light emitted by different emitters of the plurality of emitters is reflected onto a same pixel of an output image. Changes in rotational speed are compensated for through increasing an emission duration for a first row driven while the reflective surface is rotating at a slower rotational speed, relative to an emission duration for a second row driven while the reflective surface is rotating at a faster rotational speed.

A device includes a plurality of first LEDs, a plurality of second LEDs, at least one controllable current source that is configured to generate at least one bias current for driving the plurality of first LEDs and the plurality of second LEDs, and a plurality of measurement circuits, each of which is configured to measure a current-voltage (I-V) performance characteristic of at least one of the plurality of first LEDs. A property of a first bias current of the at least one bias current is determined as a function of at least two measurements of the I-V performance characteristic of the at least one of the plurality of first LEDs, and the at least two measurements of the I-V performance characteristic are acquired while the first bias current is applied to the at least one of the plurality of first LEDs and the plurality of second LEDs.

Devices having dedicated light emitting diodes for performance characterization

In one example, an apparatus comprises a backplane to attach an array of light emitting diodes (LED), the backplane comprising an array of display driver circuits, each display driver circuit of the array of display driver circuits corresponding to an LED of the array of LEDs and comprising: a current driver circuit configured to supply to a current to the corresponding LED; a control signal generator circuit configured to supply a driver control signal to the current driver circuit to control the current; and one or more monitor circuits controllable to provide access to at least one of: the current, or an internal voltage of at least one of the current driver circuit or the control signal generator circuit.

Display diagnostic system

A display comprises a matrix comprising a plurality of N rows divided into a plurality of M columns of cells, each cell including a light emitting device; a scan driver providing a plurality of N scan line signals to respective rows of said matrix, each for selecting a respective row of the matrix to be programmed with pixel values; and a data driver providing a plurality of M variable level data signals to respective columns of the matrix, each for programming a respective pixel within a selected row of the matrix with a pixel value. A pulse driver provides a plurality of N driving signals to respective rows of the matrix, each driving signal comprising successive sequences of pulses enabling the cells to emit light according to their programmed pixel values during respective sub-frames of successive frames to be displayed. The data driver is arranged to provide variable level data signals to respective pixels within a selected row of the matrix during a limited number of sub-frames of a frame, the variable data levels corresponding to a programmed value of a plurality of bits of a pixel value for a frame. The data driver is further arranged to provide data signals to respective pixels within a selected row of the matrix during a remaining number of sub-frames of a frame, the data signals each corresponding to a programmed value of a single bit of a pixel value for a frame.

Display using analog and digital subframes

In an embodiment, a method includes accessing a first rendered frame generated based on a first viewing direction of a user. The first rendered frame may be generated at a first frame rate. The method includes generating, based on the first rendered frame, one or more sub-frames at a second frame rate that is higher than the first frame rate. A first sub-frame of the one or more sub-frames is generated by determining a second viewing direction of the user based on sensor data and applying one or more transformations to the first frame based on the second viewing direction. The method includes outputting the one or more sub-frames for display at the second frame rate.

Pan-warping and modifying sub-frames with an up-sampled frame rate

Techniques are described for operating a display comprising an array of emitters arranged in at least one column. A data shifting circuit stores digital data or an analog representation thereof in a first storage element. The data shifting circuit outputs the digital data or analog representation multiple times to a display driver circuit, using a multiplexer. The first storage element can be a shift register or a capacitor. Digital data can be internally shifted within the data shifting circuit, through multiple shift registers, prior to output to the display driver circuit. An analog representation can be stored and read from the same capacitor without internal shifting. The display driver circuit drives a different emitter of the column each time. A scanning assembly including a reflective surface that receives light from the emitter array forms an output image by rotating the reflective surface in synchronization with driving of the emitters.

Data shifting circuit for a current mode display

A system includes a plurality of first LEDs, a plurality of second LEDs, a first controllable current source that is configured to generate a first bias current for driving a first one of the plurality of first LEDs and a plurality of first ones of the plurality of second LEDs, a first measurement circuit that is configured to measure a first current-voltage (I-V) performance characteristic of the first one of the plurality of first LEDs, and a lens that is arranged to receive light from the plurality of second LEDs. A property of the first bias current is determined as a function of at least two measurements of the first I-V performance characteristic that are acquired while the first bias current is applied to the first one of the plurality of first LEDs and the plurality of first ones of the plurality of second LEDs.

Systems having dedicated light emitting diodes for performance characterization

In an embodiment, a method includes accessing a first rendered frame generated at a first frame rate. The method includes generating, based on the first rendered frame, one or more sub-frames at a second frame rate that is higher than the first frame rate. A first sub-frame of the one or more sub-frames is generated by determining a displacement measure associated with an anticipated movement of an optics component of a display system and applying, based on the displacement measure, one or more transformations to the first rendered frame to generate the first sub-frame. The first sub-frame is to be perceived by a user using the optics component of the display system. The method includes outputting the one or more sub-frames for display at the second frame rate. The one or more sub-frames are perceived by the user using the optics component of the display system.

Techniques are described for operating a display system comprising a light source and a scanning assembly. The light source includes a plurality of emitters arranged in a column and circuitry configured to drive the emitters based on image data. The scanning assembly includes a reflective surface facing the light source, the reflective surface being rotatable in at least one dimension. A control signal including periodic, non-linear pulses causes the reflective surface to rotate through a range of scan angles, thereby forming an output image based on reflection of emitted light. The image data is supplied to the light source in synchronization with the rotational movement of the reflective surface. Changes in rotation speed due to the non-linear nature of the control signal are compensated for by adjusting emission durations for different rows to provide different emission durations at different times based on changes in the linearity of the control signal.

Systems and methods for controlling a display apparatus are provided. In one example, an apparatus comprises a display comprising a plurality of light emitting diodes (LED), a display control circuit configured to generate display control signals, and a test module configured to generate test control signals. In a test operation mode, at least one LED of the plurality of LEDs is configured to be controlled by the test control signals from the test module to conduct at least one test output current. The test module can determine electrical characteristics of the at least one LED based on the at least one test output current. The display control circuit can adjust the display control signals based on the electrical characteristics of the at least one LED.

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Ilias Pappas