Light-emitting display device and driving device thereof

Abstract

A light-emitting display device and a driving device thereof, wherein the light-emitting display device comprises a plurality of scanning lines, a plurality of driving lines, a plurality of light-emitting elements, and a driving device, wherein the light-emitting elements are respectively and correspondingly arranged between matrices defined by the plurality of scanning lines and the plurality of driving lines, and the driving device comprises a control circuit, a balance line, and a charge sharing circuit, wherein the control circuit is used to generate a balance signal group, wherein the balance signal group is related to the average distribution of charges on the driving lines, and the charge sharing circuit is electrically connected between the driving lines and the balance lines, and is electrically connected to the control circuit to receive the balance signal group from the control circuit, and the charge sharing circuit switches at least two of the driving lines with the balance line to one of a connection state and a disconnection state according to the control of the balance signal group. In this way, the charges on the driving lines are evenly distributed to balance the voltages on the driving lines, so that the display effect is more consistent.

Description

Technical Field

[0001] The present invention relates to a light emitting diode display technology, in particular to a light emitting display device and a driving device thereof. Background Art

[0002] The existing LED matrix includes multiple scanning lines, multiple driving lines and multiple LEDs, and the driving circuit performs time-sharing display on the LED matrix in a time-sharing scanning manner. When the same scanning line is to display the same brightness, the bias voltage of the LED corresponding to each driving line before turning on is inconsistent, so that the actual turning-on time of the LED is different, and the driving current provided by the current source of the driving circuit flows through the LEDs for different total times, resulting in uneven brightness. This phenomenon is particularly obvious in the low brightness area of ​​the LED matrix, because the pulse time of the current source corresponding to the low brightness area is short, resulting in a large difference in the time of the current flowing through the LEDs, so the phenomenon of uneven brightness is more obvious.

[0003] Therefore, the problem of uneven brightness caused by the existing technology is currently to be improved. Summary of the invention

[0004] A first object of the present invention is to provide a light-emitting display device that can emit light uniformly.

[0005] The light-emitting display device of the present invention comprises a plurality of scanning lines, a plurality of driving lines, a plurality of light-emitting elements, and a driving device.

[0006] The scanning lines are arranged along a row direction.

[0007] The driving lines are arranged perpendicular to the scanning lines along a column direction.

[0008] The light emitting elements are respectively and correspondingly arranged between matrices defined by the plurality of scanning lines and the plurality of driving lines.

[0009] The driving device includes a control circuit, a balance line, and a charge sharing circuit.

[0010] The control circuit is used to generate a balanced signal group, and the balanced signal group is related to the average distribution of charges on the driving line.

[0011] The charge sharing circuit is electrically connected between the driving line and the balance line, and is electrically connected to the control circuit to receive the balance signal group from the control circuit. The charge sharing circuit switches at least two of the driving lines and the balance line between a connection state and a disconnection state according to the control of the balance signal group.

[0012] In the light-emitting display device of the present invention, the balance signal group has multiple control signals, and the charge sharing circuit includes multiple switches, each switch has a first end electrically connected to the corresponding driving line, a second end electrically connected to the balance line, and a control end receiving the corresponding control signal, and each switch is switched between conduction and non-conduction according to the control signal.

[0013] The light-emitting display device of the present invention further comprises a driving module electrically connected to the driving line, for providing a plurality of driving currents to the driving line according to a pulse width modulation signal respectively, so as to switch the driving line to a display state respectively.

[0014] The light-emitting display device of the present invention, the driving module includes a plurality of driving switches respectively grounded and used to receive the pulse width modulation signal, and a plurality of current sources respectively electrically connected to the driving switches and the driving lines. When each driving switch receives the pulse width modulation signal, it switches to a conducting state, and the corresponding current source provides the driving current to the corresponding driving line.

[0015] The light-emitting display device of the present invention, the driving module also includes a bias setting circuit electrically connected to the driving line, the bias setting circuit receives a voltage setting signal group from the control circuit, and sets the voltage of the driving line in the non-display state to a preset voltage according to the voltage setting signal group.

[0016] In the light-emitting display device of the present invention, the voltage setting signal group has multiple driving voltages, the bias setting circuit includes multiple bias control switches and multiple bias control modules, the bias control switches respectively have a first end electrically connected to the corresponding driving line, a control end receiving one of the driving voltages, and a second end, and each bias control switch switches between conduction and non-conduction according to the driving voltage, the bias control modules are respectively electrically connected to the second ends of the bias control switches, and when each bias control switch is switched to conduction, the corresponding bias control module sets the voltage of the driving line in the non-display state to the preset voltage, and the preset voltage is used to eliminate ghosting.

[0017] The light-emitting display device of the present invention, the driving device also includes a scan selector electrically connected to the scan line, the scan selector receives an input voltage, and in each scan unit time, the scan selector outputs the input voltage to a corresponding one of the scan lines.

[0018] In the light-emitting display device of the present invention, each light-emitting element includes an anode terminal and a cathode terminal. The anode terminal of the light-emitting element in each row is electrically connected to the corresponding scanning line, and the cathode terminal of the light-emitting element in each column is electrically connected to the corresponding driving line.

[0019] Furthermore, a second object of the present invention is to provide a driving device that can make a light-emitting array emit light uniformly.

[0020] The driving device of the present invention is applicable to a light-emitting array, wherein the light-emitting array comprises a plurality of scanning lines, a plurality of driving lines, and a plurality of light-emitting elements. The scanning lines are arranged in a row direction, the driving lines are arranged perpendicular to the scanning lines in a column direction, and the light-emitting elements are respectively and correspondingly arranged between matrices defined by the plurality of scanning lines and the plurality of driving lines. The driving device comprises a control circuit, a balance line, and a charge sharing circuit.

[0021] The control circuit is used to generate a balanced signal group, and the balanced signal group is related to the average distribution of charges on the driving line.

[0022] The charge sharing circuit is electrically connected between the driving line and the balance line, and is electrically connected to the control circuit to receive the balance signal group from the control circuit. The charge sharing circuit switches at least one of the driving line and the balance line to one of a connection state and a disconnection state according to the control of the balance signal group.

[0023] The effect of the present invention is that when the charge sharing circuit switches the balance line and at least two of the driving lines to an electrically connected state according to the balance control signal, the balance line provides a charging and discharging path for the light-emitting elements on the driving lines, so that the charges on the driving lines are evenly distributed to balance the voltages on the driving lines, eliminate the voltage drops between the driving lines, and thus make the display effect more consistent. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Other features and effects of the present invention will be clearly presented in the embodiments with reference to the accompanying drawings, in which:

[0025] Figure 1 is a circuit diagram illustrating an embodiment of a light emitting display device of the present invention;

[0026] Figure 2 is a circuit diagram to assist in explaining the embodiment;

[0027] Figure 3 is a circuit diagram illustrating a first application circuit of the embodiment;

[0028] Figure 4 is a timing diagram to assist in explaining the first application circuit;

[0029] Figure 5 is a circuit diagram illustrating a second application circuit of the embodiment;

[0030] Figure 6is a timing diagram to assist in explaining the second application circuit;

[0031] Figure 7 is a circuit diagram illustrating a third application circuit of the embodiment; and

[0032] Figure 8 is a timing diagram to assist in explaining the third application circuit. DETAILED DESCRIPTION

[0033] See also Figure 1 , Figure 2 An embodiment of the light-emitting display device of the present invention includes a plurality of scanning lines 2, a plurality of driving lines 3, a plurality of light-emitting elements 4, and a driving device 5.

[0034] The scanning lines 2 are arranged along a row.

[0035] The driving lines 3 are arranged perpendicular to the scanning lines 2 along a column direction.

[0036] The light emitting elements 4 are respectively disposed between matrices defined by the plurality of scanning lines 2 and the plurality of driving lines 3 . The scanning lines 2 , the driving lines 3 , and the light emitting elements 4 together form a light emitting array.

[0037] Each light-emitting element 4 includes an anode terminal 41 and a cathode terminal 42. The anode terminal 41 of the light-emitting element 4 in each row is electrically connected to the corresponding scanning line 2, and the cathode terminal 42 of the light-emitting element 4 in each column is electrically connected to the corresponding driving line 3.

[0038] The driving device 5 includes a control circuit 51 , a balance line 52 , a charge sharing circuit 53 , a driving module 54 , and a scan selector 55 .

[0039] The control circuit 51 is used to generate a balanced signal group. The balanced signal group has a plurality of control signals, and each of the control signals is related to the average distribution of the charges on the driving line 3 .

[0040] The charge sharing circuit 53 is electrically connected between the driving line 3 and the balance line 52, and is electrically connected to the control circuit 51 to receive the balance signal group from the control circuit 51. The charge sharing circuit 53 controls at least two of the driving lines 3 and the balance line 52 to be simultaneously switched between a connection state and a disconnection state according to the control of the balance signal group.

[0041] The charge sharing circuit 53 includes a plurality of switches 531, each switch 531 having a first end electrically connected to the corresponding driving line 3, a second end electrically connected to the balance line 52, and a control end receiving a corresponding control signal, and each switch 531 is switched between conducting and non-conducting according to the control signal.

[0042] The driving module 54 is electrically connected to the driving line 3 and is used to provide multiple driving currents to the driving line 3 according to a pulse width modulation signal (PWM) so as to switch the driving line 3 to a display state. The driving module 54 includes multiple driving switches 541 respectively grounded and used to receive the pulse width modulation signal, multiple current sources 542 respectively electrically connected to the driving switches 541 and the driving line 3, and a bias setting circuit 543.

[0043] When each driving switch 541 receives the pulse width modulation signal, it switches to the on state, and the corresponding current source 542 provides the driving current to the corresponding driving line 3 to provide a constant current to the corresponding light-emitting element 4 and adjust the effective time of the constant current to change the corresponding brightness of the light-emitting element 4.

[0044] The bias setting circuit 543 is electrically connected to the driving line 3 and receives a voltage setting signal group from the control circuit 51, and sets the voltage of the driving line 3 in the non-display state to a preset voltage for eliminating ghost images according to the voltage setting signal group. Figure 3 DX, the voltage setting signal group has multiple driving voltages, the bias setting circuit 543 includes multiple bias control switches 544, and multiple bias control modules 545, the bias control switches 544 respectively have a first end electrically connected to the corresponding driving line 3, a control end receiving one of the driving voltages, and a second end, and each bias control switch 544 switches between conduction and non-conduction according to the driving voltage, the bias control modules 545 are respectively electrically connected to the second ends of the bias control switches 544, when each bias control switch 544 is switched to conduction, the corresponding bias control module 545 sets the voltage of the driving line 3 in the non-display state to the preset voltage.

[0045] The scan selector 55 is electrically connected to the scan line 2, and receives an input voltage. In each scan unit time, the scan selector 55 outputs the input voltage to a corresponding one of the scan lines 2 to provide the electric energy required for the light-emitting element 4 to emit light. It should be noted that the number of the driving lines 3 that are switched to the electrical connection state with the balance line 52 by the charge sharing circuit 53 according to the balance control signal can be adjusted according to design requirements, for example, it can be one or more than three, and should not be limited to the disclosure of this embodiment.

[0046] Related References Figure 3 , Figure 4 , illustrating a first application circuit of the embodiment. In the first application circuit, the number of driving lines 3 controlled to display the same grayscale is three, and the number of scanning lines 2 is one, so the number of light-emitting elements 4, driving modules 54, and bias setting circuits 543 are three each.

[0047] Before the switches 531 of the charge sharing circuit 53 receive the corresponding control signals, the bias control switches 544 of each bias setting circuit 543 receive the voltage setting signal group from the control circuit 51 and switch to the on state, and the bias control module 545 provides a ghost elimination voltage DT to the cathode terminal 42 of the light-emitting element 4 on the driving line 3, so that the light-emitting element 4 is in a reverse bias state. At this time, the voltages on the corresponding nodes DX1~DX3 rise, and then the bias control module 545 provides a recovery voltage Dummy to the cathode terminal 42 of the light-emitting element 4 on the driving line 3. At this time, the voltages VDX1~V DX3 then gradually decreases so that the potential difference between the anode terminal 41 and the cathode terminal 42 of the corresponding light-emitting element 4 is close to the forward conduction voltage value. Then, the switch 531 of the charge sharing circuit 53 receives the corresponding control signal and switches to the on state, so that the driving line 3 charges and discharges the balance line 52 to achieve charge balance. At this time, the voltages VDX1~VDX3 on the corresponding nodes DX1~DX3 gradually average and tend to be consistent. When the logic level of the control signal is switched to 0, the driving switch 541 of the driving module 54 receives the corresponding pulse width modulation signal and switches to the on state, so that the corresponding current source 542 provides the driving current to the corresponding driving line 3.

[0048] Related References Figure 5 , Figure 6, describing a second application circuit of the embodiment. The second application circuit is different from the first application circuit in that a specific method is provided for different light-emitting elements 4 to display different grayscale values. The number of driving lines 3 controlled to display corresponding grayscale values ​​is three, and the number of scanning lines 2 is one. Therefore, the number of light-emitting elements 4, driving modules 54, and bias setting circuits 543 are three respectively. The control signals received by the driving switches 541 corresponding to the nodes DX1~DX3 are respectively the first pulse width modulation signal, the second pulse width modulation signal, and the third pulse width modulation signal. The control signals received by the switches 531 corresponding to the nodes DX1~DX3 are respectively the first control signal, the second control signal, and the third control signal.

[0049] Before the switches 531 of the charge sharing circuit 53 each receive the corresponding first to third control signals, the bias control switches 544 of each bias setting circuit 543 receive the voltage setting signal group from the control circuit 51 and switch to the on state, and the bias control module 545 provides a ghost elimination voltage DT to the cathode terminal 42 of the light-emitting element 4 on the driving line 3, so that the light-emitting element 4 is in a reverse bias state. At this time, the voltages on the corresponding nodes DX1~DX3 rise, and then the bias control module 545 provides the recovery voltage Dummy to the cathode terminal 42 of the light-emitting element 4 on the driving line 3. At this time, the voltages VDX1~VDX3 on the corresponding nodes DX1~DX3 gradually decrease, so that the potential difference between the anode terminal 41 and the cathode terminal 42 of the corresponding light-emitting element 4 is close to the forward conduction voltage value, that is, the recovery voltage Dummy, and then the switch 531 of the charge sharing circuit 53 receives the corresponding control signal and switches to the on state. , so that the driving line 3 charges and discharges the balancing line 52 to achieve charge balance. Since the first pulse width modulation signal received by the driving switch 541 corresponding to the node DX1 has the lowest conduction width, it means that the grayscale value to be displayed by the light-emitting element 4 is lower. Therefore, the first control signal cycle width received by the corresponding switch 531 is the longest, that is, the charge balance can be achieved in a more sufficient time. The conduction widths of the second and third pulse width modulation signals gradually increase, which means that the grayscale values ​​to be displayed by the remaining corresponding light-emitting elements 4 gradually increase. Therefore, the cycle widths of the second and third control signals received by the corresponding switch 531 gradually decrease, and the time for charge balance also gradually decreases. At this time, the voltages VDX1-VDX3 on the corresponding nodes DX1-DX3 gradually average and tend to be consistent. When the logic level of the control signal is switched to 0, the driving switch 541 of the driving module 54 receives the corresponding pulse width modulation signal and switches to the conducting state, so that the corresponding current source 542 provides the driving current to the corresponding driving line 3.

[0050] Related References Figure 7 , Figure 8 , describing a third application circuit of the embodiment, the circuit architecture of the third application circuit is the same as that of the second application circuit, but the difference is that the duty cycle of the conduction width of the third pulse width modulation signal received by the driving switch 541 corresponding to the node DX3 is 100%, which means that the grayscale value to be displayed by the light-emitting element 4 is the highest. Therefore, the cycle width of the third control signal received by the corresponding switch 531 is zero, that is, no charge balancing is required. The remaining circuit operations are the same as those described above, so they are not repeated here.

[0051] In summary, each bias control switch 544 receives a voltage setting signal group and switches to the on state, and the corresponding bias control module 545 provides a ghost elimination voltage DT to the cathode terminal 42 of the light-emitting element 4 on the driving line 3 to eliminate the ghost effect. Then, the bias control module 545 provides a recovery voltage Dummy to the cathode terminal 42 of the light-emitting element 4 on the driving line 3, so that the voltage VDX1~VDX3 on the nodes DX1~DX3 gradually decreases, thereby making the corresponding light-emitting element 4 close to the forward conduction state. Then, the switch 531 of the charge sharing circuit 53 receives a corresponding control signal and switches to the on state. state, so that the driving line 3 charges and discharges the balance line 52 to achieve charge balance, and then the voltages VDX1~VDX3 on the corresponding nodes DX1~DX3 tend to be consistent. When the logic level of the control signal is switched to 0, the driving switch 541 of the driving module 54 receives the corresponding pulse width modulation signal and switches to the on state, so that the corresponding current source 542 provides a driving current to the corresponding driving line 3, and makes the display effect more consistent. In addition, according to the grayscale value required to be displayed by the light-emitting element 4, control signals with different conduction lengths can be provided to control the effective time of charge balance, so that the purpose of the present invention can be achieved.

[0052] The above is only a preferred embodiment of the present invention, and should not be used to limit the scope of the present invention. That is, any simple equivalent changes and modifications made according to the claims and description of the present invention are still within the scope of the present invention.

Claims

1. A light-emitting display device, characterized in that: Include: A plurality of scanning lines are arranged along a row with each other; A plurality of driving lines are arranged perpendicular to the scanning lines along a column direction; A plurality of light emitting elements are respectively and correspondingly arranged between matrices defined by the plurality of scanning lines and the plurality of driving lines; and A driving device, comprising: a control circuit for generating a balanced signal group, wherein the balanced signal group has a plurality of control signals and is related to the average distribution of the charge on the driving line, A balance line, a charge sharing circuit electrically connected between the driving line and the balance line, and electrically connected to the control circuit to receive the balance signal group from the control circuit, and the charge sharing circuit switches at least two of the driving lines and the balance line between a connection state and a disconnection state according to the control of the balance signal group, the charge sharing circuit includes a plurality of switches, each switch having a first end electrically connected to the corresponding driving line, a second end electrically connected to the balance line, and a control end receiving a corresponding control signal, and each switch switches between conduction and non-conduction according to the control signal, and A driving module is electrically connected to the driving lines and is used to provide a plurality of driving currents to the driving lines according to a pulse width modulation signal, so as to switch the driving lines to a display state respectively.

2. The light-emitting display device according to claim 1, characterized in that: The driving module includes a plurality of driving switches which are grounded respectively and used to receive the pulse width modulation signal, and a plurality of current sources which are electrically connected to the driving switches and the driving lines respectively. When each driving switch receives the pulse width modulation signal, it switches to a conducting state, and the corresponding current source provides the driving current to the corresponding driving line.

3. The light-emitting display device according to claim 1, characterized in that: The driving module further includes a bias setting circuit electrically connected to the driving line, the bias setting circuit receives a voltage setting signal group from the control circuit, and sets the voltage of the driving line in the non-display state to a preset voltage according to the voltage setting signal group.

4. The light-emitting display device according to claim 3, characterized in that: The voltage setting signal group has multiple driving voltages, and the bias setting circuit includes multiple bias control switches and multiple bias control modules. The bias control switches respectively have a first end electrically connected to the corresponding driving line, a control end receiving one of the driving voltages, and a second end, and each bias control switch switches between conduction and non-conduction according to the driving voltage. The bias control modules are respectively electrically connected to the second ends of the bias control switches. When each bias control switch is switched to conduction, the corresponding bias control module sets the voltage of the driving line in the non-display state to the preset voltage, and the preset voltage is used to eliminate ghosting.

5. The light-emitting display device according to claim 1, characterized in that: The driving device further includes a scan selector electrically connected to the scan lines, the scan selector receiving an input voltage, and in each scan unit time, the scan selector outputs the input voltage to a corresponding one of the scan lines.

6. The light-emitting display device according to claim 1, characterized in that: Each light emitting element includes an anode terminal and a cathode terminal. The anode terminals of the light emitting elements in each row are electrically connected to the corresponding scanning lines, and the cathode terminals of the light emitting elements in each column are electrically connected to the corresponding driving lines.

7. A driving device, applicable to a light-emitting array, the light-emitting array comprising a plurality of scanning lines, a plurality of driving lines, and a plurality of light-emitting elements, the scanning lines are arranged in a row direction, the driving lines are arranged perpendicular to the scanning lines in a column direction, and the light-emitting elements are respectively arranged in a matrix defined by the plurality of scanning lines and the plurality of driving lines, characterized in that: The driving device comprises: a control circuit for generating a balanced signal set, the balanced signal set being related to the average distribution of charge on the drive line; A balance line; a charge sharing circuit electrically connected between the driving line and the balance line, and electrically connected to the control circuit to receive the balance signal group from the control circuit, and the charge sharing circuit switches at least one of the driving line and the balance line to one of a connection state and a disconnection state according to the control of the balance signal group, and A driving module is electrically connected to the driving lines and is used to provide a plurality of driving currents to the driving lines according to a pulse width modulation signal, so as to switch the driving lines to a display state respectively.

Images