# US 12,682,829 B1 · Apparatuses, systems, and methods for microLED (mLED) backplane architectures > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 12,682,829 B1 - Document ID: US12682829B1 - Status: Granted - Kind: B1 - Application number: 18/627,398 - Filed: 2024-04-04 - Granted: 2026-07-14 - Earliest claimed: 2021-03-26 - Assignees: Forth Dimension Display, Ltd - Applicants: Forth Dimension Displays Ltd. - Inventors: Christopher Robert Chalmers; Debra Jane Lefley; Jason Darren Drew; Jedrzej Nowakowski; Neil Mallory; Ruiyan Zhao - Web page: https://patentgrep.com/patent/US12682829B1 ## CPC - G09G 3/32: semiconductive, e.g. using light-emitting diodes [LED] - G09G 3/2074: {using sub-pixels} - G09G 3/2085: {Special arrangements for addressing the individual elements of the matrix, other than by driving respective rows and columns in combination} - G09G 3/2018: {by time modulation using two or more time intervals} - G09G 2300/0842: forming a memory circuit, e.g. a dynamic memory with one capacitor - G09G 2300/0857: Static memory circuit, e.g. flip-flop - G09G 2300/0861: with additional control of the display period without amending the charge stored in a pixel memory, e.g. by means of additional select electrodes - G09G 2310/0251: Precharge or discharge of pixel before applying new pixel voltage - G09G 2310/0259: with use of an analog or digital ramp generator in the column driver or in the pixel circuit - G09G 2310/027: Details of drivers for data electrodes, the drivers handling digital grey scale data, e.g. use of D/A converters - G09G 2310/0291: Details of output amplifiers or buffers arranged for use in a driving circuit - G09G 2310/08: Details of timing specific for flat panels, other than clock recovery - G09G 2320/0233: Improving the luminance or brightness uniformity across the screen - G09G 2320/0276: for the purpose of adaptation to the characteristics of a display device, i.e. gamma correction - G09G: ARRANGEMENTS OR CIRCUITS FOR CONTROL OF INDICATING DEVICES USING STATIC MEANS TO PRESENT VARIABLE INFORMATION (arrangements for transferring data between digital computers and displays G06F3/14; static indicating arrangements comprising an association of a number of separate sources or light control cells G09F9/00; static indicating arrangements comprising integral associations of a number of light sources H01J, H01K, H10H, H05B33/12; scanning, transmission or reproduction of documents or the like, e.g. facsimile transmission, details thereof H04N1/00) ## Abstract Methods, apparatuses, and systems to control current through a sub-pixel micro-LED (mLED) of a mLED display using a dynamic current mirror are taught. A dynamic current mirror is shifted to phase zero. Phase zero includes establishing a first voltage for a sub-pixel mLED control transistor. The first voltage is produced using a predetermined reference current. An energy storage device used in the sub-pixel mLED is charged to the first voltage during phase zero. The dynamic current mirror is shifted to phase one. In phase one, the first voltage is used with the sub-pixel mLED control transistor to pass an illumination current through the sub-pixel mLED. ## Claims ### Claim 1 A method to control current through a sub-pixel micro-LED (mLED) of a mLED display using a dynamic current mirror, comprising: shifting the dynamic current mirror to phase zero, phase zero comprising: establishing a first voltage for a sub-pixel mLED control transistor, the first voltage produced using a predetermined reference current, wherein the establishing includes a threshold voltage for the sub-pixel mLED control transistor; charging an energy storage device used in the sub-pixel mLED to the first voltage during phase zero; and shifting the dynamic current mirror to phase one, phase one comprising: utilizing the first voltage with the sub-pixel mLED control transistor to pass an illumination current through the sub-pixel mLED. ### Claim 2 (depends on 1) The method of claim 1, wherein the predetermined reference current is created by a digital signal and a digital-to-analog (DA) converter is used to create an analog signal from the digital signal, the analog signal is used during the establishing. ### Claim 3 (depends on 1) The method of claim 1, wherein the energy storage device is a capacitor and during the phase zero a voltage on the capacitor is applied to a gate terminal and a source terminal of the sub-pixel mLED control transistor. ### Claim 4 A computer-readable storage medium storing program code for causing a data processing system to perform the steps comprising: shifting a dynamic current mirror to phase zero, phase zero comprising: establishing a first voltage for a sub-pixel mLED control transistor, the first voltage produced using a predetermined reference current, wherein the establishing includes a threshold voltage for the sub-pixel mLED control transistor; charging an energy storage device used in the sub-pixel mLED to the first voltage during phase zero; and shifting the dynamic current mirror to phase one, phase one comprising: utilizing the first voltage with the sub-pixel mLED control transistor to pass an illumination current through the sub-pixel mLED. ### Claim 5 (depends on 4) The computer-readable storage medium of claim 4, wherein the predetermined reference current is created by a digital signal and a digital-to-analog (DA) converter is used to create an analog signal from the digital signal, the analog signal is used during the establishing. ### Claim 6 (depends on 4) The computer-readable storage medium of claim 4, wherein the energy storage device is a capacitor and during the phase zero a voltage on the capacitor is applied to a gate terminal and a source terminal of the sub-pixel mLED control transistor. ### Claim 7 A sub-pixel micro-LED (mLED) drive circuit to control current through a sub-pixel micro-LED (mLED) of a mLED display using a dynamic current mirror, comprising: a sub-pixel mLED control transistor; a sub-pixel energy storage device; and two switches, the two switches are operable in two phases as follows: 1. in phase 0 operation, the two switches are configured to charge the sub-pixel energy storage device to a first voltage from a reference current source, and the first voltage includes a threshold voltage for the sub-pixel mLED control transistor; 2. in phase 1 operation, the two switches are configured to disconnect from the reference current source and to use the first voltage with the sub-pixel mLED control transistor to pass an illumination current through the sub-pixel mLED.