Organic light emitting diode printing head

Abstract

The invention provides an organic light-emitting diode printing head which comprises a control unit, a plurality of light-emitting units and an organic light-emitting diode. The control unit is configured to output a scanning signal, an enable signal and a correction signal. Each light-emitting unit comprises a first driving circuit and a second driving circuit. The first driving circuit includes a first capacitor and a first switch configured to store a correction voltage corresponding to the correction signal in the first capacitor in response to a trigger pulse of the scan signal, the first switch being controlled by the correction voltage. The second driving circuit includes a second capacitor and a second switch, and is configured to store an enable voltage corresponding to the enable signal in the second capacitor in response to a trigger pulse of the scan signal, and the second switch is controlled by the enable voltage. The organic light emitting diode obtains a driving current related to the correction voltage through the driving path when both the first switch and the second switch are turned on.

Description

Technical Field

[0001] The present invention relates to the technical field of organic light-emitting diode print heads, and particularly to an organic light-emitting diode print head having a light-emitting unit made of a thin-film transistor and an organic light-emitting diode. Background Art

[0002] A light-emitting diode print head (LED Print Head, LPH) is a light-emitting technology for a print head. It mainly uses a gallium arsenide semiconductor process to manufacture a plurality of light-emitting modules, and each light-emitting module has a plurality of light-emitting components and their driving circuits. Each light-emitting module is a die. These light-emitting modules are fixedly arranged on a printed circuit board by die bonding technology. Therefore, in order to manufacture the above print head, complicated processes such as wafer dicing and die bonding are required. Summary of the Invention

[0003] In view of this, the present invention provides an organic light-emitting diode print head manufactured by an AMOLED process, including a control unit and a plurality of light-emitting units. The control unit is configured to output a scan signal, an enable signal, and a correction signal. The plurality of light-emitting units are coupled to the control unit, and each light-emitting unit includes a first driving circuit, a second driving circuit, and an organic light-emitting diode. The first driving circuit includes a first capacitor and a first switch, and is configured to store a correction voltage corresponding to the correction signal in the first capacitor in response to a trigger pulse of the scan signal, and the first switch is controlled by the correction voltage. The second driving circuit includes a second capacitor and a second switch, and is configured to store an enable voltage corresponding to the enable signal in the second capacitor in response to a trigger pulse of the scan signal, and the second switch is controlled by the enable voltage. The organic light-emitting diode is coupled to the first switch and the second switch. The first switch and the second switch are located on the driving path of the organic light-emitting diode. The upstream end of the driving path has a working voltage, and the organic light-emitting diode obtains a driving current related to the correction voltage via the driving path when both the first switch and the second switch are turned on.

[0004] In some embodiments, the control unit further includes a scan signal generation circuit, an enable signal generation circuit, and a correction signal generation circuit. The scan signal generation circuit includes a plurality of scan signal output terminals configured to output scan signals via these scan signal output terminals. The enable signal generation circuit includes a plurality of enable signal output terminals configured to output enable signals. The correction signal generation circuit includes a plurality of correction signal output terminals configured to output correction signals. These light-emitting units are divided into a plurality of groups, each scan signal output terminal is coupled to the light-emitting units with the same serial number in these groups, these enable signal output terminals are respectively coupled to these groups one-to-one and each enable signal output terminal is coupled to all the light-emitting units in the same group, and these correction signal output terminals are respectively coupled to these groups one-to-one and each correction signal output terminal is coupled to all the light-emitting units in the same group.

[0005] In some embodiments, the scan signal generation circuit includes a plurality of shift registers, each shift register includes a shift input terminal and a shift output terminal, and these shift registers are serially connected in sequence such that the shift output terminal of the previous-stage shift register is coupled to the shift input terminal of the next-stage shift register. These shift output terminals are respectively coupled to the corresponding light-emitting units one-to-one to sequentially transmit trigger pulses to these light-emitting units via these shift output terminals.

[0006] In summary, for the organic light-emitting diode print head according to some embodiments of the present invention, the light-emitting units made of conductive thin-film transistors, a plurality of organic light-emitting diodes, and their driving circuits can be directly fabricated on a substrate, which can simplify the fabrication steps. On the other hand, the first capacitor of the light-emitting unit stores the correction voltage corresponding to the correction signal, and does not discharge the voltage to a low potential, which can ensure that the charging and discharging voltage changes of the capacitor do not fluctuate too much, accelerate the response time of the light-emitting unit to emit light (under a correction signal with a short cycle time, the light-emitting unit can quickly perform continuous actions of emitting light and extinguishing), and can protect the components from being damaged, extend the service life, and accelerate the response time of the organic light-emitting diode.

[0007] The detailed features and advantages of the present invention are described in detail in the following embodiments. The content is sufficient for any person skilled in the art to understand the technical content of the present invention and implement it accordingly. And according to the content disclosed in this specification, the scope of the patent application, and the drawings, any person skilled in the art can easily understand the related purposes and advantages of the present invention. Description of the Drawings

[0008] Figure 1 It is a block diagram of an organic light-emitting diode print head according to some embodiments of the present invention.

[0009] Figure 2 It is a feeder diagram of an organic light-emitting diode print head according to some embodiments of the present invention.

[0010] Figure 3 In some embodiments of the present invention, it is a circuit diagram of an implementation manner of a light-emitting unit.

[0011] Figure 4 In some embodiments of the present invention, it is a circuit diagram of another implementation manner of a light-emitting unit.

[0012] Figure 5 In some embodiments of the present invention, it is a signal timing diagram of an organic light-emitting diode print head.

[0013] Figure 6 In some embodiments of the present invention, it is another feeder diagram of an organic light-emitting diode print head.

[0014] Figure 7 In some embodiments of the present invention, it is a circuit diagram of a displacement buffer and a light-emitting unit.

[0015] Figure 8 It is Figure 6 the signal timing diagram of the organic light-emitting diode print head in

[0016] Figure 9 In some embodiments of the present invention, it is a plan view of an organic light-emitting diode print head.

[0017] Description of reference numerals:

[0018] 10. Organic light-emitting diode print head;

[0019] 102. Control unit; 104. Light-emitting unit; 106. First drive circuit; 108. Second drive circuit;

[0020] 110. Organic light-emitting diode; 112. First capacitor; 114. First switch; 116. Second capacitor; 118. Second switch;

[0021] 120. Third switch;

[0022] 114a, 118a, 120a, 122a, 124a, 136a, 138a, 140a, 142a, 144a, 146a. First end;

[0023] 114b, 118b, 120b, 122b, 124b, 136b, 138b, 140b, 142b, 144b, 146b. Second end;

[0024] 114c, 118c, 120c, 122c, 124c, 136c, 138c, 140c, 142c, 144c, 146c. Control end;

[0025] 122. Fourth switch; 124. Fifth switch; 126. Scanning signal generation circuit; 126a. Scanning signal output terminal; 128. Enable signal generation circuit; 128a. Enable signal output terminal; 130. Correction signal generation circuit;

[0026] 130a. Correction signal output terminal; 132. Group; 132a. First group; 132b. Second group; 134. Shift register; 1341. Shift input terminal; 1342. Shift output terminal; 1343. Frequency receiving terminal; 1344. Clear terminal; 136. Sixth switch; 138. Seventh switch;

[0027] 140. Eighth switch; 142. Ninth switch; 144. Tenth switch; 146. Eleventh switch; 148. Third capacitor;

[0028] 150. Substrate;

[0029] EP. Start signal; L. Axis; N1. First node; N2. Second node; S2. Trigger pulse;

[0030] t1, t2, t3, t4, t5, t6, t7, t8. Time points;

[0031] VDD. Operating voltage; VSS. Ground voltage. Detailed implementation manners

[0032] Please refer to Figure 1 . Figure 1 In some embodiments of the present invention, it is a block diagram of an organic light-emitting diode print head 10. The organic light-emitting diode print head 10 includes a control unit 102 and a plurality of light-emitting units 104. These light-emitting units 104 are coupled to the control unit 102. The light-emitting unit 104 includes a light-emitting component made by a conductive thin film technology and its driving circuit, so these light-emitting units 104 can be formed on the substrate (see Figure 9 substrate 150 therein) according to a predetermined layout manner. The control unit 102 is configured to output a scanning signal, an enable signal, and a correction signal. Specifically, the control unit 102 includes a scanning signal generation circuit 126, an enable signal generation circuit 128, and a correction signal generation circuit 130, which are respectively configured to output a scanning signal, an enable signal, and a correction signal. The scanning signal is used to specify the light-emitting unit 104 to be controlled. The correction signal determines the light-emitting brightness of the specified light-emitting unit 104. The enable signal determines whether the specified light-emitting unit 104 emits light or not.

[0033] Please refer to Figure 2 . Figure 2In some embodiments of the present invention, the feeder diagram of the organic light emitting diode print head 10 shows the connection relationship between the control unit 102 and the light emitting units 104. These light emitting units 104 are divided into a plurality of groups 132. Each group 132 includes a plurality of light emitting units 104. Each group 132 includes the same number of light emitting units 104. As an example, the number of light emitting units 104 is 128, but the present invention is not limited thereto. For example, it can be 64, 256 or other numbers. The scan signal generation circuit 126 includes a plurality of scan signal output terminals 126a, configured to output scan signals via these scan signal output terminals 126a. Each scan signal output terminal 126a is coupled to the light emitting unit 104 with the same serial number in these groups 132. For example, the first light emitting unit 104 in each group 132 is coupled to the first scan signal output terminal 126a; the second light emitting unit 104 in each group 132 is coupled to the second scan signal output terminal 126a; and so on. Here, the serial numbers of the light emitting units 104 in these groups 132 are not uniformly restricted to start from the same side. That is to say, the serial number can start from one side of the light emitting unit 104 or from the other side of the light emitting unit 104. As Figure 2 shown, the first scan signal output terminal 126a is coupled to the first left light emitting unit 104 in some of the groups 132 and the first right light emitting unit 104 in some of the groups.

[0034] Figure 5 In some embodiments of the present invention, the signal timing diagram of the organic light emitting diode print head 10 is shown. Here, an exemplary display of the correction signal, scan signal and enable signal received by a light emitting unit 104 is shown. As Figure 5 shown, the scan signal includes a trigger pulse S2, used to indicate that the light emitting unit 104 performs an action in response to the trigger pulse S2. The trigger pulse S2 is a square wave, changing from a low potential to a high potential, maintaining for a period of time and then returning to the low potential, but the present invention is not limited thereto. For example, according to the design requirements, the trigger pulse S2 is a square wave changing from a high potential to a low potential and then returning to the high potential in some embodiments.

[0035] Refer to Figure 2 and Figure 5 . The scan signals output by each scan signal output terminal 126a are different from each other (i.e., the time points of the trigger pulses S2 are different). Therefore, at each time point, only one scan signal output terminal 126a designates the light emitting units 104 with the same serial number in the connected groups 132. For example, at the first time point, the first light emitting unit 104 in each group 132 is designated to perform an action; at the next time point (the second time point), the second light emitting unit 104 in each group 132 is designated to perform an action; and so on.

[0036] As Figure 2 shown, the enabling signal generation circuit 128 includes a plurality of enabling signal output terminals 128a, configured to output enabling signals via these enabling signal output terminals 128a. These enabling signal output terminals 128a are respectively coupled to these groups 132 one-to-one, and each enabling signal output terminal 128a is coupled to all the light emitting units 104 in the same group 132. Therefore, all the light emitting units 104 in the same group 132 will receive the same enabling signal. However, since only one light emitting unit 104 in the same group 132 will be designated (receive the trigger pulse S2) at a time point, only the designated light emitting unit 104 will perform the actions corresponding to the enabling signal, and the light emitting units 104 that do not receive the trigger pulse S2 will not perform the actions corresponding to the enabling signal. In addition, the enabling signals output by each enabling signal output terminal 128a are independent of each other and not affected, so the designated light emitting units 104 in each group 132 can be independently controlled as needed.

[0037] Similarly, the calibration signal generation circuit 130 includes a plurality of calibration signal output terminals 130a, configured to output calibration signals via these calibration signal output terminals 130a. These calibration signal output terminals 130a are respectively coupled to these groups 132 one-to-one, and each calibration signal output terminal 130a is coupled to all the light emitting units 104 in the same group 132. Therefore, all the light emitting units 104 in the same group 132 will receive the same calibration signal. However, since only one light emitting unit 104 in the same group 132 will be designated (receive the trigger pulse S2) at a time point, only the designated light emitting unit 104 will perform the actions corresponding to the calibration signal, and the light emitting units 104 that do not receive the trigger pulse S2 will not perform the actions corresponding to the calibration signal. In addition, the calibration signals output by each calibration signal output terminal 130a are independent of each other and not affected, so the designated light emitting units 104 in each group 132 can be independently controlled as needed.

[0038] In some embodiments, if the resolution of the organic light-emitting diode print head 10 is expected to reach 600 DPI (Dots Per Inch), approximately 5,120 light-emitting units 104 are required. According to the foregoing, each group 132 has 128 light-emitting units 104, so 40 groups 132 are needed. At this time, the number of scan signal output terminals 126a is 128, and the numbers of enable signal output terminals 128a and calibration signal output terminals 130a are both 40. In addition, since the light-emitting units 104 in the same group 132 share the same enable signal output terminal 128a and the same calibration signal output terminal 130a, the calibration signal and the enable signal are both serialized data, and 128 signals are required to respectively indicate the actions that the corresponding 128 light-emitting units 104 should perform.

[0039] Next, the specific composition of the light-emitting component and its driving circuit inside the light-emitting unit 104 will be described. Figure 3 In some embodiments of the present invention, it is a circuit diagram of an implementation manner of the light-emitting unit 104. As Figure 3 shown, each light-emitting unit 104 includes a first driving circuit 106, a second driving circuit 108, and an organic light-emitting diode 110. The first driving circuit 106 includes a first capacitor 112 and a first switch 114. The first driving circuit 106 receives a scan signal and a calibration signal, and is configured to store a calibration voltage corresponding to the calibration signal in the first capacitor 112 in response to a trigger pulse S2 of the scan signal. The first switch 114 is coupled to the first capacitor 112 and is controlled by the calibration voltage. The second driving circuit 108 includes a second capacitor 116 and a second switch 118. The second driving circuit 108 receives a scan signal and an enable signal, and is configured to store an enable voltage corresponding to the enable signal in the second capacitor 116 in response to a trigger pulse S2 of the scan signal. The second switch 118 is coupled to the second capacitor 116 and is controlled by the enable voltage. The organic light-emitting diode 110 is coupled to the first switch 114 and the second switch 118, and the first switch 114 and the second switch 118 are located on the driving path of the organic light-emitting diode 110. The upstream end of the driving path has a working voltage VDD. The organic light-emitting diode 110 obtains a driving current related to the calibration voltage via the driving path when both the first switch 114 and the second switch 118 are turned on, and then emits light. Therefore, each organic light-emitting diode 110 can obtain a calibrated driving current according to the calibration voltage to emit light with consistent brightness.

[0040] As Figure 3As shown, the second switch 118, the first switch 114, and the organic light-emitting diode 110 are sequentially coupled along the flow direction of the driving current. Specifically, the first switch 114 includes a first terminal 114a, a second terminal 114b, and a control terminal 114c. The second switch 118 includes a first terminal 118a, a second terminal 118b, and a control terminal 118c. The second terminal 118b of the second switch 118 is coupled to the first terminal 114a of the first switch 114. The second terminal 114b of the first switch 114 is coupled to the anode of the organic light-emitting diode 110. The cathode of the organic light-emitting diode 110 receives the ground voltage VSS. The control terminal 114c of the first switch 114 is coupled to the first capacitor 112 to receive the calibration voltage of the first capacitor 112. Thus, the on state of the first switch 114 is determined by the calibration voltage. The control terminal 118c of the second switch 118 is coupled to the second capacitor 116 to receive the enable voltage of the second capacitor 116. Thus, the on state of the second switch 118 is determined by the enable voltage. Here, the first switch 114 and the second switch 118 are NMOS transistors. The first terminals (114a, 118a) are drains, the second terminals (114b, 118b) are sources, and the control terminals (114c, 118c) are gates. In some embodiments, when the first switch 114 is an NMOS transistor, the calibration voltage determines the voltage between the gate and the source (VGS) of the first switch 114 and simultaneously determines the drain-source conduction current. In some embodiments, the first switch 114 is referred to as a driving switch, for example, a driving thin-film transistor (driving TFT); the remaining switches (such as the second switch 118 and the switches described later) are referred to as switching switches, for example, switching thin-film transistors (switching TFT).

[0041] As Figure 3 shown, the first driving circuit 106 further includes a third switch 120. The third switch 120 includes a first terminal 120a, a second terminal 120b, and a control terminal 120c. The first terminal 120a of the third switch 120 receives a calibration signal. The second terminal 120b of the third switch 120 is coupled to the first capacitor 112. The control terminal 120c of the third switch 120 receives a scan signal. Thus, the on state of the third switch 120 is determined by the scan signal. Here, the third switch 120 is an NMOS transistor. The first terminal 120a is a drain, the second terminal 120b is a source, and the control terminal 120c is a gate. Refer to Figure 3 and Figure 5, in response to the trigger pulse S2 of the scan signal, the third switch 120 is turned on, that is, the first end 120a of the third switch 120 is conducted with the second end 120b of the third switch 120, so that the first capacitor 112 receives the calibration signal via the third switch 120 and is charged to the calibration voltage. Due to process errors, the characteristics of the transistors and the organic light-emitting diodes 110 in each light-emitting unit 104 may be inconsistent, resulting in inconsistent light-emitting brightness of the organic light-emitting diodes 110 in these light-emitting units 104. Therefore, a suitable calibration voltage value is given to each corresponding light-emitting unit 104 through the calibration signal to adjust the driving current given to the corresponding organic light-emitting diode 110, so that each organic light-emitting diode 110 emits light with consistent brightness. It should be noted in particular that in Figure 5 , although the calibration signal corresponding to the period of the trigger pulse S2 is at a high potential in terms of digital logic, the voltage level (i.e., the voltage value) of the high potential can be slightly adjusted according to requirements, so that the voltage between the gate and the source of the first switch 114 is greater than the critical voltage to turn on the first switch 114, and the drain-source current is adjusted by changing the voltage value between the gate and the source (if the brightness needs to be reduced, the calibration voltage is reduced to reduce the drain-source current; otherwise, the calibration voltage is increased).

[0042] As Figure 3 shown, the second driving circuit 108 further includes a fourth switch 122. The fourth switch 122 includes a first end 122a, a second end 122b and a control end 122c. The first end 122a of the fourth switch 122 receives the enable signal. The second end 122b of the fourth switch 122 is coupled to the second capacitor 116. The control end 122c of the fourth switch 122 receives the scan signal. Therefore, the on state of the fourth switch 122 is determined by the scan signal. Here, the fourth switch 122 is an NMOS transistor, the first end 122a is the drain, the second end 122b is the source, and the control end 122c is the gate. Refer to Figure 3 and Figure 5, in response to the trigger pulse S2 of the scan signal, the fourth switch 122 is turned on, that is, the first terminal 122a and the second terminal 122b of the fourth switch 122 are conducted, so that the second capacitor 116 receives the enable signal via the fourth switch 122 and is charged to the enable voltage. When the enable signal is at a low potential, the second capacitor 116 cannot be charged and the second switch 118 is turned on, so the second switch 118 is in the off state; when the enable signal is at a high potential, the enable voltage of the second capacitor 116 turns on the second switch 118. Therefore, the second switch 118 can be controlled to be turned on or off by the enable signal, so as to determine whether the organic light-emitting diode 110 can emit light. In other words, the calibration voltage obtained by the first switch 114 can always turn on the first switch 114, and whether the organic light-emitting diode 110 can obtain the driving current depends on whether the second switch 118 is turned on. When the second switch 118 is turned on (that is, both the first switch 114 and the second switch 118 are turned on), the organic light-emitting diode 110 obtains the driving current and emits light; when the second switch 118 is turned off, the driving path of the organic light-emitting diode 110 is not conducted and the organic light-emitting diode 110 does not emit light.

[0043] As described above, the control terminals 120c of the third switch 120 and 122c of the fourth switch 122 both receive the scan signal, that is, the control terminal 120c of the third switch 120 and the control terminal 122c of the fourth switch 122 are coupled to each other. Therefore, the third switch 120 and the fourth switch 122 are turned on simultaneously in response to the trigger pulse S2 of the scan signal, that is, their respective first terminals (120a, 122a) and second terminals (120b, 122b) are conducted, so that the first capacitor 112 and the second capacitor 116 can receive the calibration signal and the enable signal respectively. The time length of the aforementioned trigger pulse S2 only needs to enable the first capacitor 112 to be charged to the calibration voltage and the second capacitor 116 to be charged to the enable voltage. It should be noted that the time length of the trigger pulse S2 depends on the printing speed. For example, when the printing speed is 600 PPM (Pages per Minute, PPM), the time length of its trigger pulse S2 is greater than the time length of the trigger pulse S2 when the printing speed is 1200 PPM.

[0044] As Figure 3As shown, each light-emitting unit 104 further includes a fifth switch 124. The fifth switch 124 is located on the driving path of the organic light-emitting diode 110. The first terminal 124a of the fifth switch 124 receives the operating voltage VDD, the second terminal 124b of the fifth switch 124 is coupled to the first terminal 118a of the second switch 118, and the control terminal 124c of the fifth switch 124 receives the scan signal. The fifth switch 124 is a PMOS transistor. Therefore, the operating mode of the fifth switch 124 is opposite to that of the aforementioned third switch 120 and fourth switch 122. The fifth switch 124 turns off in response to the trigger pulse S2 of the scan signal and turns on during the light-emitting period of the organic light-emitting diode 110 (during the period when the control terminal 124c of the fifth switch 124 receives the trigger pulse S2). Therefore, it can be ensured that the driving path of the organic light-emitting diode 110 is not conducting during the trigger pulse S2.

[0045] In some embodiments, if it can be determined that the critical voltage of the second switch 118 is within the expected range, such that the operation of the second switch 118 proceeds as described above, then the fifth switch 124 can be omitted (in this case, the first terminal 118a of the second switch 118 receives the operating voltage VDD).

[0046] Figure 4 It is a circuit diagram of another implementation manner of the light-emitting unit 104 in some embodiments of the present invention. Figure 4 And Figure 3 The difference lies in the different coupling orders of the first switch 114, the second switch 118, and the organic light-emitting diode 110, but the internal component connection relationships and the corresponding signal feeding of the first driving circuit 106 and the second driving circuit 108 are the same. In Figure 4 , the first switch 114, the organic light-emitting diode 110, and the second switch 118 are sequentially coupled along the direction of the driving current. Specifically, the first terminal 114a of the first switch 114 is coupled to the operating voltage VDD, and the second terminal 114b of the first switch 114 is coupled to the anode of the organic light-emitting diode 110. The first terminal 118a of the second switch 118 is coupled to the cathode of the organic light-emitting diode 110, and the second terminal 118b receives the ground voltage VSS. Figure 4 The operating principle of the components in Figure 3 is the same as the relevant description in

[0047] Please refer to Figure 6 and Figure 8 . Figure 6 It is another feeder diagram of the organic light-emitting diode printhead 10 in some embodiments of the present invention, showing how to form the aforementioned scan signal through the displacement buffer 134 and input it to each light-emitting unit 104. Figure 8 It is Figure 6 the signal timing diagram of the organic light-emitting diode printhead 10 in

[0048] As Figure 6 shown, in some embodiments, the scan signal generation circuit 126 includes a plurality of shift registers 134. Each shift register 134 includes a shift input terminal 1341 and a shift output terminal 1342. These shift registers 134 are connected in series in sequence, such that the shift output terminal 1342 of the previous-stage shift register 134 is coupled to the shift input terminal 1341 of the subsequent-stage shift register 134. The shift input terminal 1341 of the first-stage shift register 134 receives the start signal EP. These shift registers 134 further include a frequency receiving terminal 1343 to receive a frequency signal and operate according to the frequency signal. These shift registers 134 shift the state of the shift input terminal 1341 to the shift output terminal 1342 according to the period of the frequency signal. Therefore, as Figure 8 shown, the pulse of the start signal EP is successively shifted to the subsequent-stage shift registers 134 along with the period of the frequency signal. The shift output terminals 1342 of these shift registers 134 are respectively coupled to the corresponding light-emitting units 104 one-to-one, so as to use the shifted start signal EP as the trigger pulse S2 of the scan signal and transmit it to these light-emitting units 104 respectively via these shift output terminals 1342 in sequence. These shift registers 134 further include a clear terminal 1344 to reset the shift output terminal 1342 when triggered by a reset signal.

[0049] Figure 7 In some embodiments of the present invention, it is the circuit diagram of the shift register 134 and the light-emitting unit 104. As Figure 7As shown, in some embodiments, each displacement buffer 134 includes a sixth switch 136, a seventh switch 138, an eighth switch 140, a ninth switch 142, a tenth switch 144, an eleventh switch 146, and a third capacitor 148. Among them, the sixth switch 136 has a first terminal 136a, a second terminal 136b, and a control terminal 136c. The seventh switch 138 has a first terminal 138a, a second terminal 138b, and a control terminal 138c. The eighth switch 140 has a first terminal 140a, a second terminal 140b, and a control terminal 140c. The ninth switch 142 has a first terminal 142a, a second terminal 142b, and a control terminal 142c. The tenth switch 144 has a first terminal 144a, a second terminal 144b, and a control terminal 144c. The eleventh switch 146 has a first terminal 146a, a second terminal 146b, and a control terminal 146c. Here, these switches (136, 138, 140, 142, 144, 146) are NMOS transistors, the first terminals (136a, 138a, 140a, 142a, 144a, 146a) are the drains, the second terminals (136b, 138b, 140b, 142b, 144b, 146b) are the sources, and the control terminals (136c, 138c, 140c, 142c, 144c, 146c) are the gates.

[0050] The first terminal 136a of the sixth switch 136 is coupled to the control terminal 136c to form the aforementioned displacement input terminal 1341. The second terminal 138b of the seventh switch 138 receives the ground voltage VSS, and the control terminal 138c of the seventh switch 138 is the aforementioned clear terminal 1344. The first terminal 138a of the seventh switch 138 is coupled to the third capacitor 148. The first terminal 140a and the control terminal 140c of the eighth switch 140 receive the operating voltage VDD, and the second terminal 140b is coupled to the first terminal 142a of the ninth switch 142. The second terminal 142b of the ninth switch 142 receives the ground voltage VSS. The control terminal 142c of the ninth switch 142 is coupled to the second terminal 136b of the sixth switch 136. The first terminal 144a of the tenth switch 144 is the aforementioned frequency receiving terminal 1343, which receives the aforementioned frequency signal. The second terminal 144b of the tenth switch 144 is coupled to the first terminal 146a of the eleventh switch 146, and the displacement output terminal 1342 is therebetween. The second terminal 146b of the eleventh switch 146 receives the ground voltage VSS. The control terminal 144c of the tenth switch 144 is coupled to the second terminal 136b of the sixth switch 136, and the control terminal 146c of the eleventh switch 146 is coupled to the second node N2. The third capacitor 148 is coupled between the control terminal 144c and the second terminal 144b of the tenth switch 144. That is to say, one end (the first node N1) of the third capacitor 148 is coupled to the second terminal 136b of the sixth switch 136; the other end of the third capacitor 148 is coupled to the aforementioned displacement output terminal 1342.

[0051] Please refer to Figure 8 , which is Figure 6 the signal timing diagram of the organic light-emitting diode print head 10 in Figure 6 , showing the signal relationship between the front-stage shift buffer 134 and the rear-stage shift buffer 134. Here, the signal operation timing of the first-stage and second-stage shift buffers 134 in

[0052] is taken as an example for illustration. At time point t1 (the starting point of the first-stage shift buffer 134): In the first-stage shift buffer 134, the frequency signal received by the frequency receiving end 1343 is at a high potential, the start signal EP received by the shift input end 1341 is at a high potential, the reset signal received by the clear end 1344 is at a low potential, the sixth switch 136, the eighth switch 140, the ninth switch 142, and the tenth switch 144 are turned on, and the seventh switch 138 and the eleventh switch 146 are turned off. At this time, the first node N1 is at a high potential, and the shift output end 1342 of the first-stage shift buffer 134 is at a low potential.

[0053] At time point t3 (the scan generation point of the first-stage shift buffer 134): In the first-stage shift buffer 134, the frequency signal received by the frequency receiving end 1343 changes from a low potential to a high potential, and the shift output end 1342 of the first-stage shift buffer 134 is at a high potential, that is, the trigger pulse S2 of the scan signal is generated. Since the shift input end 1341 of the second-stage shift buffer 134 is coupled to the shift output end 1342 of the second-stage shift buffer 134, it is also at a high potential (at this moment, the second-stage shift buffer 134 enters the starting point). When the trigger pulse S2 of the scan signal is at a high potential, the control end 122c turns on the fourth switch 122 in response to the scan signal, so that the enable signal is input to the light-emitting unit 104, and the control end 120c turns on the third switch 120 in response to the scan signal, so that the correction signal is input to the light-emitting unit 104. During the duration of time point t3 (between time point t3 and time point t4), the control end 118c turns on the second switch 118 in response to the enable signal, and the control end 114c turns on the first switch 114 in response to the enable signal, and the drive path obtains a drive current to make the organic light-emitting diode 110 emit light.

[0054] At time point t4 (the scanning end point of the first - stage displacement buffer 134): Among these displacement buffers 134, the frequency signal received by the frequency receiver 1343 becomes low - potential, and the reset signal received by the clear terminal 1344 turns into high - potential, causing the displacement output terminals 1342 of these displacement buffers 134 to be reset to low - potential. In the first - stage displacement buffer 134, the sixth switch 136, the ninth switch 142, and the tenth switch 144 are closed, the seventh switch 138, the eighth switch 140, and the eleventh switch 146 are open, and the first node N1 is at low - potential. The displacement output terminal 1342 of the first - stage displacement buffer 134 is at low - potential, and the scanning signal ends.

[0055] At time point t5: The second - stage displacement buffer 134 enters the scanning generation point, and the third - stage displacement buffer 134 enters the starting point.

[0056] At time point t6: The reset signal received by the clear terminal 1344 turns into high - potential, causing the displacement output terminals 1342 of these displacement buffers 134 to be reset to low - potential. The scanning of the second - stage displacement buffer 134 ends.

[0057] At time point t7: The third - stage displacement buffer 134 enters the scanning generation point.

[0058] Therefore, the number of displacement buffers 134 can be increased according to the number of light - emitting units 104, and each displacement buffer 134 can sequentially generate the trigger pulse S2 of the scanning signal according to the above actions.

[0059] Please refer to Figure 9 , Figure 9 FIG. is a schematic plan view of the organic light - emitting diode printhead 10 in some embodiments of the present invention. In some embodiments, these light - emitting units 104 are configured to be located on the substrate 150 and are distributed linearly. These light - emitting units 104 are divided into a plurality of groups 132, and these groups 132 include a plurality of first groups 132a and a plurality of second groups 132b. Each group 132 is located in one of the sections on the axis L of the substrate 150. These groups (132a, 132b) are arranged in an interleaved manner and respectively in a first light - emitting order (such as Figure 9 the arrow direction in is from left to right) and a second light - emitting order opposite to the first light - emitting order (such as Figure 9The arrow in the figure points from right to left) to light up these light-emitting units 104 of itself. In other words, the first group 132a and the second group 132b are arranged alternately (for example, the first group 132a has odd serial numbers and the second group 132b has even serial numbers, and vice versa), and the first group 132a lights up the light-emitting units 104 in sequence according to the first light-emitting order, and the second group 132b lights up the light-emitting units 104 in sequence according to the second light-emitting order. Thus, compared with the same-direction lighting method, it is not easy to see the step difference feeling for each printing line.

[0060] In some embodiments, the light-emitting units 104 are made by using conductive thin-film technology. That is to say, the aforementioned organic light-emitting diodes 110, the first driving circuit 106, and the second driving circuit 108 are made of transparent conductive thin films such as indium tin oxide (ITO), indium zinc oxide (IZO), etc., and are encapsulated on the substrate 150 (such as a glass substrate). Therefore, the aforementioned plurality of light-emitting units 104 can be formed on the substrate 150 according to a predetermined layout method without going through steps such as wafer dicing and die bonding. Moreover, the conductive thin film can also form wires, which can save the wire bonding step. In some embodiments, the shift register 134 is made by using conductive thin-film technology and is encapsulated on the same substrate 150 as the light-emitting units 104. The aforementioned transistor is a thin film transistor (TFT). Among them, the organic light-emitting diode 110 can be an active-matrix organic light-emitting diode (AMOLED), so that the organic light-emitting diode 110 has the advantages of small volume, self-luminosity, and fast response speed.

[0061] In some embodiments, the control unit 102 is a control circuit such as a microprocessor, a digital signal processor (DSP), or an application-specific integrated circuit (ASIC) that can output the aforementioned timing signals.

[0062] In summary, according to some embodiments of the present invention, the organic light-emitting diode print head 10 made by using conductive thin-film technology includes light-emitting units 104 made of transistors and a plurality of organic light-emitting diodes 110 and their driving circuits, which can be directly fabricated on the substrate 150, simplifying the fabrication steps. On the other hand, the first capacitor 112 of the light-emitting unit 104 stores the correction voltage corresponding to the correction signal and does not discharge the voltage to a low potential (that is, the discharge change of the first capacitor 112 is limited), which can accelerate the response time of the light-emitting unit 104 to emit light (under a correction signal with a shorter cycle time, the light-emitting unit 104 can quickly perform continuous actions of emitting light and extinguishing), and can ensure that the charging and discharging voltage changes of the capacitor do not fluctuate excessively to cause component damage, thereby extending the service life and accelerating the response time of the organic light-emitting diode 110.

[0063] Although the technical content of the present invention has been disclosed above in preferred embodiments, it is not intended to limit the present invention. Any person skilled in the art, without departing from the spirit of the present invention, making some modifications and refinements should be covered within the scope of the present invention. Therefore, the protection scope of the present invention shall be subject to the scope defined by the claims of this application.

Claims

1. An organic light emitting diode print head, characterized in that: include: A control unit configured to output a scan signal, an enable signal and a calibration signal; as well as A plurality of light emitting units are coupled to the control unit, each of the light emitting units comprising: A first driving circuit includes a first capacitor and a first switch, configured to store a correction voltage corresponding to the correction signal in the first capacitor in response to a trigger pulse of the scanning signal, wherein the first switch is controlled by the correction voltage; A second driving circuit includes a second capacitor and a second switch, configured to store an enabling voltage corresponding to the enabling signal in the second capacitor in response to the trigger pulse of the scanning signal, and the second switch is controlled by the enabling voltage; as well as An organic light emitting diode is coupled to the first switch and the second switch, wherein the first switch and the second switch are located on a driving path of the organic light emitting diode, an upstream end of the driving path has a working voltage, and the organic light emitting diode obtains a driving current related to the correction voltage through the driving path when the first switch and the second switch are both turned on.

2. The organic light emitting diode print head according to claim 1, wherein: in, The first driving circuit also includes a third switch, the first switch and the third switch respectively include a first end, a second end and a control end, the first end of the third switch receives the correction signal, the second end of the third switch is coupled to the first capacitor, the control end of the third switch receives the scanning signal, and in response to the trigger pulse of the scanning signal, the first end of the third switch and the second end of the third switch are turned on, so that the first capacitor receives the correction signal through the third switch and is charged to the correction voltage, and the control end of the first switch is coupled to the first capacitor to be controlled by the correction voltage to turn on the first end of the first switch and the second end of the first switch.

3. The organic light emitting diode print head according to claim 1, wherein: in, The second driving circuit further includes a fourth switch, wherein the second switch and the fourth switch respectively include a first end, a second end, and a control end, the first end of the fourth switch receives the enable signal, the second end of the fourth switch is coupled to the second capacitor, the control end of the fourth switch receives the scan signal, and in response to the trigger pulse of the scan signal, the first end of the fourth switch and the second end of the fourth switch are turned on, so that the second capacitor receives the enable signal through the fourth switch and is charged to the enable voltage, and the control end of the second switch is coupled to the second capacitor to be controlled by the enable voltage to turn on or off the first end of the second switch and the second end of the second switch.

4. The organic light emitting diode print head according to claim 1, wherein: in, The first driving circuit further includes a third switch, and the second driving circuit further includes a fourth switch, wherein the third switch and the fourth switch respectively include a first end, a second end, and a control end, wherein the first end of the third switch receives the calibration signal, the second end of the third switch is coupled to the first capacitor, the first end of the fourth switch receives the enable signal, the second end of the fourth switch is coupled to the second capacitor, the control end of the third switch and the control end of the fourth switch are coupled to each other to receive the scan signal, and the third switch and the fourth switch simultaneously respond to the trigger pulse of the scan signal to conduct the first end and the second end of each.

5. The organic light emitting diode print head according to claim 1, wherein: in, The second switch, the first switch and the organic light emitting diode are coupled in sequence along the flow direction of the driving current.

6. The organic light emitting diode print head according to claim 1, wherein: in, The first switch, the organic light emitting diode and the second switch are coupled in sequence along the flow direction of the driving current.

7. The organic light emitting diode print head according to claim 1, wherein: in, Each of the light emitting units further comprises: The fifth switch is located on the driving path of the organic light emitting diode and receives the scanning signal, so as to be closed in response to the trigger pulse of the scanning signal and opened in a light emitting period of the organic light emitting diode.

8. The organic light emitting diode print head according to claim 1, wherein: in, The control unit comprises: A scanning signal generating circuit, comprising a plurality of scanning signal output terminals, configured to output the scanning signal via the scanning signal output terminals; an enable signal generating circuit, comprising a plurality of enable signal output terminals, configured to output the enable signal via the enable signal output terminals; and A correction signal generating circuit, comprising a plurality of correction signal output terminals, configured to output the correction signal via the correction signal output terminals; Wherein, the light-emitting units are divided into a plurality of groups, each of the scan signal output terminals is coupled to the light-emitting units in the group having the same serial number as the scan signal output terminal, the enable signal output terminals are coupled to the groups one-to-one and each of the enable signal output terminals is coupled to all the light-emitting units in the same group, and the correction signal output terminals are coupled to the groups one-to-one and each of the correction signal output terminals is coupled to all the light-emitting units in the same group.

9. The organic light emitting diode print head according to claim 8, wherein: in, The scanning signal generating circuit includes a plurality of displacement registers, each of which includes a displacement input end and a displacement output end. The displacement registers are connected in series in sequence so that the output end of the displacement register of the previous stage is coupled to the displacement input end of the displacement register of the next stage, wherein the output ends are respectively coupled one-to-one to the corresponding light-emitting units so as to transmit the trigger pulses to the light-emitting units in sequence through the output ends.

10. The organic light emitting diode print head according to claim 1, wherein: in, The light-emitting units are configured to be distributed in a line, and the light-emitting units are divided into a plurality of groups, each of which is located in one of the sections of the line. The groups are arranged in a staggered manner and light up their own light-emitting units in a first light-emitting sequence and a second light-emitting sequence, respectively, wherein the first light-emitting sequence is opposite to the second light-emitting sequence.

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