Driver circuit for light emitting modules with combined active and passive matrix functionalities

Patent metadata

Field	Value
Publication number	US-12555525-B2
Application number	US-202218572232-A
Country	US
Kind code	B2
Filing date	Jun 30, 2022
Priority date	Jun 30, 2021
Publication date	Feb 17, 2026
Grant date	Feb 17, 2026

Abstract

A driver circuit for driving a matrix of N×M pixels of a light emitting module. Each pixel is composed of at least three types of light emitting elements. The light emitting elements are driven by a modulation control signal. The driver circuit is embedded in a TFT layer. It is configured to cooperate with N multiplexers provided in an external driver circuit, each multiplexer being configured to drive one line of M pixels. It is also configured to cooperate with one external current source per type of light emitting element, each external current source being mirrored M times on the matrix of the driver circuit and being arranged in series with a signal switch for generating the control signal provided for each of the M columns.

First claim

The invention claimed is:

1 . A driver circuit for driving a matrix of N×M pixels of a light emitting module,
wherein each pixel is composed of at least three types of light emitting elements, the light emitting elements being driven by a modulation control signal of period T configured to switch the light emitting elements on and off at most during 1/Nth of the period T,
wherein the period T corresponds to the duration of a frame, and
wherein the driver circuit is embedded in a thin-film transistor (TFT) layer such that a switch is embedded in each light emitting element, and is configured to cooperate with N multiplexers provided in an external driver circuit, each multiplexer being configured to drive a respective line of M pixels, and the combination of multiplexers is configured to address all the pixels of the N×M matrix during one period of the modulation control signal, and
each pixel of a group of M pixels is shown consecutively during at most 1/Nth of the period T,
at least one external current source per type of light emitting element to drive the N×M matrix,
and wherein each external current source is mirrored M times on the TFT layer of the driver circuit and is arranged in series with a modulation control signal switch for generating the modulation control signal provided for each of the M columns of the matrix.

2 . The driver circuit according to claim 1 wherein the modulation control signal is a pulse width modulation signal, and the modulation control signal switch is a pulse width modulation switch.

3 . The driver circuit according to claim 1 , wherein the three types of light emitting elements emit a different color, wherein the different colors are at least red, green, and blue.

4 . The driver circuit according to claim 1 , wherein the external current sources are provided on a printed circuit board (PCB) arranged under the matrix.

5 . The driver circuit according to claim 1 , wherein the multiplexers are provided on a printed circuit board (PCB) arranged under the matrix.

6 . The driver circuit according to claim 1 , wherein the multiplexers are transistors implemented with a low drain-source on-resistance field effect transistor (Rds(on) FET).

7 . The driver circuit according to claim 1 , wherein the lines of the multiplexers for addressing the pixels are such that one line for addressing the pixels comprises pixels of different rows.

8 . The driver circuit according to claim 1 , wherein the lines of the multiplexers for addressing the pixels are such that at least two pixels in the same column are addressed by the same line.

9 . The driver circuit according to claim 1 , wherein the order in which the multiplexers are addressed is not linear.

10 . The driver circuit according to claim 1 , wherein the pixels are addressed several times during one frame.

11 . The driver circuit according to claim 1 , wherein colors of sub-pixels composing a pixel are at least red, green, blue, and may further comprise any one of red, green, blue, white, yellow, cyan, magenta or any other color.

12 . The driver circuit according to claim 1 , wherein the light emitting elements are any one of light-emitting diodes (LEDs), organic light-emitting diodes (OLEDs), quantum dot light-emitting diodes (QD-LEDs), electroluminescent quantum light-emitting diodes (EL-QLEDs), active-matrix organic light-emitting diodes (AMOLEDs), mini-LEDs, micro-LEDs.

13 . The driver circuit according to claim 1 , wherein the light emitting elements are provided with quantum dots to generate the different colors of emission.

14 . A chip configured to cooperate with the driver circuit of claim 2 , the chip comprising N multiplexers, each multiplexer being configured to drive one line of M pixels, and the combination of multiplexers being configured to address all the pixels of the N×M matrix during one period of the Pulse Width Modulated signal.

15 . A chip configured to cooperate with the driver circuit of claim 1 , the chip comprising one current source per sub-pixel to drive the N×M matrix, said current source being mirrored M times on the TFT layer and arranged in series with a PWM switch provided in each of the M columns of the matrix.

16 . A chip configured to cooperate with the driver circuit and comprising the chip of claim 14 and a chip comprising one current source per sub-pixel to drive the N×M matrix, said current source being mirrored M times on the thin-film transistor (TFT) layer and arranged in series with a pulse width modulation (PWM) switch provided in each of the M columns of the matrix.

17 . A light emitting module comprising a matrix of N×M pixels, at least one driver circuit associated to said matrix according to claim 1 , and for each driver circuit and associated matrix, a chip configured to cooperate with the driver circuit, the chip comprising N multiplexers, each multiplexer being configured to drive one line of M pixels, and the combination of multiplexers being configured to address all the pixels of the N×M matrix during one period of the Pulse Width Modulated signal and a chip configured to cooperate with the driver circuit, the chip comprising one current source per sub-pixel to drive the N×M matrix, said current source being mirrored M times on the thin-film transistor (TFT) layer and arranged in series with a pulse width modulation (PWM) switch provided in each of the M columns of the matrix.

18 . A display module comprising at least one light emitting module according to claim 17 .

19 . A tiled display comprising at least one display module according to claim 18 .

Assignees

• Barco Nv

Inventors

• Willem Patrick
• Van Den Bossche Bart
• Gerets Peter
• Van Eessen Wim

Classifications

• G09G2300/026

  Video wall, i.e. juxtaposition of a plurality of screens to create a display screen of bigger dimensions · CPC title

• G09G3/32

  semiconductive, e.g. using light-emitting diodes [LED] · CPC title

• G09G2310/0297

  Special arrangements with multiplexing or demultiplexing of display data in the drivers for data electrodes, in a pre-processing circuitry delivering display data to said drivers or in the matrix panel, e.g. multiplexing plural data signals to one D/A converter or demultiplexing the D/A converter output to multiple columns · CPC title

• G09G3/2014

  by modulation of the duration of a single pulse during which the logic level remains constant · CPC title

• G09G3/3216 Primary

  using a passive matrix · CPC title