Display device which improves ghost images and related driving circuit and method

Patent metadata

Field	Value
Publication number	US-11514850-B1
Application number	US-202217697960-A
Country	US
Kind code	B1
Filing date	Mar 18, 2022
Priority date	Jan 29, 2022
Publication date	Nov 29, 2022
Grant date	Nov 29, 2022

Abstract

A display device includes a luminescent array and a column driver. The cathodes of the first row of luminescent devices are coupled to a first word line. The anodes of the second row of luminescent devices are coupled to a second word line. In the mth column of luminescent devices, the anode of a first luminescent device in the first row is coupled to the cathode of a second luminescent device in the second row. The column driver includes a switch and two multiplexers. The switch controls the path between input signal and the mth column of luminescent devices. The first multiplexer provides a first driving signal for charging the parasite capacitor in the switch and the first luminescent device during a first period. The second multiplexer provides a second driving signal for charging the second luminescent device and discharging the parasite capacitor in the switch during a second period.

First claim

What is claimed is:

1. A display device which improves ghost images, comprising:
a luminescent array comprising M columns and N rows of luminescent devices, wherein:
among an n th row of luminescent devices in the N rows of luminescent devices, a cathode of each luminescent device is coupled to an n th word line;
among an (n+1) th row of luminescent devices in the N rows of luminescent devices, an anode of each luminescent device is coupled to an (n+1) th word line;
among an m th column of luminescent devices in the M columns of luminescent devices, an anode of a first luminescent device located on the n th row is coupled to a cathode of a second luminescent device located on the (n+1) th row;
M and N are integers larger than 1;
m is an integer between 1 and M;
n is an integer between 1 and N; and

a column driver, comprising:
M select switches configured to control signal transmission paths between an input signal and the M columns of luminescent devices, wherein an m th select switch among the M select switches is configured to control a signal transmission path between the input signal and the m th column of luminescent devices;
a first multiplexer configured to provide a first driving signal according to a first address signal for supplying power to a parasite capacitor in the m th select switch and the first luminescent device during a first driving period; and
a second multiplexer configured to provide a second driving signal according to a second address signal for supplying power to the second luminescent device and discharging the parasite capacitor in the m th select switch during a second diving period subsequent to the first driving period.

2. The display device of claim 1 , wherein:
the first multiplexer includes:
a first input end coupled to the input signal;
a second input end coupled to a ground voltage;
a control end coupled to the first address signal; and
an output end for outputting the first driving signal; and

the second multiplexer includes:
a first input end coupled to the input signal;
a second input end coupled to the ground voltage;
a control end coupled to the second address signal; and
an output end coupled to the n th word line and the (n+1) th word line.

3. The display device of claim 2 , wherein:
the m th select switch includes:
a first input end coupled to the output end of the first multiplexer;
a second input end coupled to the anode of the first luminescent device and the cathode of the second luminescent device; and
a control end coupled to a control signal.

4. The display device of claim 3 , wherein:
the first address signal and the second address signal are periodic signals whose level switches between a first voltage level and a second voltage level;
the first multiplexer is configured to selectively output the input signal or the ground voltage based on the first address signal for providing the first driving signal;
the second multiplexer is configured to selectively output the input signal or the ground voltage based on the second address signal for providing the second driving signal;
the first voltage level is higher than the second voltage level; and
the first address signal and the second address signal have opposite phases.

5. The display device of claim 4 , wherein:
during the first driving period when the first address signal is at the second voltage level and the second address signal is at the first voltage level, the first multiplexer is configured to output the first driving signal having the first voltage level to the first end of the m th select switch, and the n th word line is coupled to the ground voltage via the second multiplexer; and
during the second driving period when the first address signal is at the first voltage level and the second address signal is at the second voltage level, the second multiplexer is configured to output the second driving signal having the first voltage level to the (n+1) th word line, and the first end of the m th select switch is coupled to the ground voltage via the first multiplexer.

6. The display device of claim 5 , wherein:
during the first driving period when the m th select switch is turned on by the control signal associated with the m th column of luminescent devices, the first driving signal having the first voltage level is transmitted to the anode of the first luminescent device via the m th select switch, and the cathode of the first luminescent device receives the second driving signal having the second voltage level via the n th word line, thereby supplying power to the parasite capacitance in the m th select switch and the first luminescent device; and
during the second driving period when the m th select switch is turned on by the control signal associated with the m th column of luminescent devices, the second driving signal having the first voltage level is transmitted to the anode of the second luminescent device via the (n+1) th word line, and the cathode of the second luminescent device receives the first driving signal having the second voltage level via the m th select switch, thereby supplying power to the second luminescent device and discharging the parasite capacitance in the m th select switch.

7. The display device of claim 2 , wherein:
the first multiplexer further includes a first delay circuit disposed between the first input end of the first multiplexer and the output end of the first multiplexer; and
the second multiplexer further includes a second delay circuit disposed between the first input end of the second multiplexer and the output end of the second multiplexer.

8. The display device of claim 7 , wherein:
at a first time point when the first address signal switches from the first voltage level to the second voltage level, the first delay circuit is configured to delay a signal transmission from the first input end of the first multiplexer to the output end of the first multiplexer, so that the first driving signal fully switches from the second voltage level to the first voltage level at a second time point; and
at a third time point when the second address signal switches from the first voltage level to the second voltage level, the second delay circuit is configured to delay a signal transmission from the first input end of the second multiplexer to the output end of the second multiplexer, so that the second driving signal fully switches from the second voltage level to the first voltage level at a fourth time point.

9. The display device of claim 1 , wherein the M columns and N rows of luminescent devices include a light emitting diode (LED), a mini LED or a micro LED.

10. A driving method of improving ghost images, comprising:
a first multiplexer in a display device outputting a first driving signal having a first voltage level based on a first address signal, turning on a select switch for transmitting the first driving signal to an anode of a first luminescent device in the display device, and a second multiplexer in the display device outputting a second driving signal having a second voltage level to a cathode of the first luminescent device based on a second address signal during a first driving period; and
the second multiplexer outputting the second driving signal having the first voltage level to an anode of a second luminescent device in the display device based on the second address signal, the first multiplexer outputting the first driving signal having the second voltage level based on the first address signal, and turning on the select switch for transmitting the first driving signal to a cathode of the second luminescent device during a second driving period subsequent to the first

Assignees

• Qisda Corp

Inventors

• Chang Chih-Ming

Classifications

• G09G2310/0248

  Precharge or discharge of column electrodes before or after applying exact column voltages · CPC title

• G09G3/3283

  in which the data driver supplies a variable data current for setting the current through, or the voltage across, the light-emitting elements · CPC title

• G09G3/3216 Primary

  using a passive matrix · CPC title

• G09G2320/0257

  Reduction of after-image effects · CPC title

• G09G2310/08

  Details of timing specific for flat panels, other than clock recovery · CPC title