JP2006276254A - Light emitting circuit and light emitting display apparatus - Google Patents

Light emitting circuit and light emitting display apparatus Download PDF

Info

Publication number
JP2006276254A
JP2006276254A JP2005092619A JP2005092619A JP2006276254A JP 2006276254 A JP2006276254 A JP 2006276254A JP 2005092619 A JP2005092619 A JP 2005092619A JP 2005092619 A JP2005092619 A JP 2005092619A JP 2006276254 A JP2006276254 A JP 2006276254A
Authority
JP
Japan
Prior art keywords
transistor
control transistor
drive
source
light emitting
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Pending
Application number
JP2005092619A
Other languages
Japanese (ja)
Inventor
Kyoji Ikeda
恭二 池田
Original Assignee
Sanyo Electric Co Ltd
三洋電機株式会社
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Sanyo Electric Co Ltd, 三洋電機株式会社 filed Critical Sanyo Electric Co Ltd
Priority to JP2005092619A priority Critical patent/JP2006276254A/en
Publication of JP2006276254A publication Critical patent/JP2006276254A/en
Application status is Pending legal-status Critical

Links

Images

Abstract

An n-channel transistor is used as a driving transistor, and an additional circuit is not required.
By turning on transistors T1 and T2 and turning off T4 and T5, PVDD is supplied to one end of a holding capacitor Cs, and a data voltage Vdata is supplied to the other end, and a voltage of | PVDD−Vdata | Charge. Next, by turning off the transistors T1 and T2 and turning on T4 and T5, both ends of the storage capacitor Cs are connected to the gate and source of the driving transistor T3, and | PVDD−Vdata | is applied between the gate and source of the driving transistor T3. Thus, a drive current corresponding to the data voltage is obtained.
[Selection] Figure 1

Description

  The present invention relates to a circuit for driving a current-driven light emitting element such as an organic EL element, and a display device using the circuit.

  A display device using an organic EL element which is a current-driven light emitting element is known, and in particular, an active type having a driving transistor for individually driving the organic EL element of each pixel is becoming widespread.

  In such an active type display device, a pixel circuit as shown in FIG. 3 is generally used for each pixel. In this circuit, a gate line GL is provided for each horizontal line, a data line DL and a power supply line PVDD are provided for each column, and pixels are partitioned by these. Each pixel is provided with an n-channel selection transistor Tp, a storage capacitor Cs, a p-channel drive transistor Td, and an organic EL element EL. The selection transistor Tp has a drain connected to a data line DL that supplies a data voltage to each pixel in the vertical direction, a gate connected to a gate line GL that selects pixels on one horizontal line, and the source of the pixel is a drive transistor It is connected to the gate of Td.

  The drive transistor Td is a p-channel, and its source is connected to the power supply line PVDD, and its source is connected to the anode of the organic EL element EL. The cathode of the organic EL element EL is connected to the cathode power source CV. The gate of the driving transistor Td and the power supply line PVDD are connected by a storage capacitor Cs.

  In such a circuit, when the gate line GL becomes H level, the selection transistor Tp is turned on, the data voltage of the data line DL is supplied to the gate of the driving transistor Td, and the difference between the power supply line PVDD and the data voltage is supplied to the holding capacitor Cs. Is maintained. As a result, even when the driving transistor Td passes a driving current corresponding to the gate voltage and the gate line GL becomes L level, the driving transistor Td is applied to the organic EL element EL according to the voltage held in the holding capacitor Cs. A drive current is supplied, and the organic EL element EL emits light according to the data voltage.

  Here, the drive transistor Td is a p-channel type. This is because the source of the p-channel type drive transistor Td is the power supply voltage PVDD, and the drive current is determined by the gate voltage corresponding to the data voltage. However, when the drive transistor Td is changed to the n-channel, This is because the source potential of the driving transistor cannot be determined as it is, and means for determining the source potential is required.

  Note that a circuit using an n-channel transistor as a driving transistor is disclosed in Patent Document 1 and the like.

JP 2003-173154 A

  As described above, when an n-channel driving transistor is used, an additional circuit is required to determine its source potential.

  The present invention includes a light emitting element that emits light by a driving current, an n-channel driving transistor that supplies a driving current from a power source to an EL element, a gate of the driving transistor, and a write control transistor that controls connection between the power source, A storage capacitor having one end connected to the gate of the drive transistor, a selection transistor that supplies a data voltage to the other end of the storage capacitor, and a source control that turns on / off the connection between the other end of the storage capacitor and the source of the drive transistor A transistor and a drive control transistor for turning on and off the drive current of the light emitting element, and turning on the selection transistor and the write control transistor with the source control transistor and the drive control transistor turned off, Charge the storage capacitor with the difference between the power supply voltage and the data voltage. By turning off the selection transistor and the write control transistor and turning on the source control transistor and the drive control transistor, a charging voltage of the storage capacitor is applied between the gate and source of the drive transistor, and the power supply voltage and the data voltage A drive current corresponding to the difference is generated in the drive transistor, thereby causing the light emitting element to emit light.

  Preferably, the selection transistor and the write control transistor have the same polarity and are turned on / off by the same control voltage.

  Further, it is preferable that the source control transistor and the drive control transistor have the same polarity and are turned on / off by the same control voltage.

  The source control transistor, drive control transistor, write control transistor and selection control transistor are all preferably n-channel transistors.

  Preferably, the drive control transistor is disposed between a source of the drive transistor and a light emitting element, and a connection portion between the light emitting element and the drive control transistor is connected to the other end of the source control transistor. It is.

  In addition, the present invention is a light-emitting display device in which pixels for display are arranged in a matrix, and each pixel includes a light-emitting element that emits light by a drive current and an n-supply element that supplies a drive current from a power source to the light-emitting element. A channel driving transistor, a gate of the driving transistor, a write control transistor for controlling connection to a power source, a storage capacitor having one end connected to the gate of the driving transistor, and a data voltage from a data line of the storage capacitor A selection transistor to be supplied to the other end, a source control transistor for turning on and off the connection between the other end of the storage capacitor and the source of the drive transistor, and a drive control transistor for turning on and off the drive current of the light emitting element, With the source control transistor and the drive control transistor turned off, the selection transistor and By turning on the write control transistor, the storage capacitor is charged with the voltage of the difference between the power supply voltage and the data voltage, the selection transistor and the write control transistor are turned off, and the source control transistor and the drive control transistor are turned on. Thus, a charge voltage of the storage capacitor is applied between the gate and source of the drive transistor, and a drive current corresponding to the difference between the power supply voltage and the data voltage is generated in the drive transistor, thereby causing the light emitting element to emit light. And

  Thus, according to the present invention, an n-channel transistor is used as the drive transistor, but the gate-source voltage of the drive transistor is determined by the data voltage. Therefore, an n-channel transistor can be used as a drive transistor without requiring an additional circuit for fixing the source potential. In addition, as the driving data, the same data as when a conventional p-channel transistor is used can be used. Therefore, the data generation circuit and the like can be the same as those of the conventional one. In addition, the n-channel transistor has little variation in threshold voltage, can suppress the occurrence of display unevenness, and has a small hysteresis, so that an afterimage can be reduced.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

  FIG. 1 is a diagram showing a circuit configuration of the embodiment. A gate line GL is provided for each horizontal line, a data line DL and a power supply line PVDD are provided for each column, and pixels are partitioned by these. Further, a light emission set line ES is provided for each horizontal line in parallel with the gate line GL.

  Each pixel is provided with an organic EL element EL as a light emitting element and a circuit for driving the organic EL element EL. First, in order to control the drive current of the organic EL element EL, an n-channel drive transistor T3 having a drain connected to the power supply line PVDD is provided. The source of the drive transistor T3 is connected to the drain of the n-channel drive control transistor T4, and the source of the drive control transistor T4 is connected to the anode of the organic EL element EL. The cathode of the organic EL element EL is connected to a cathode power source CV.

  The source of the n-channel write control transistor T2 is connected to the gate of the drive transistor T3, and the drain thereof is connected to the power supply line PVDD. One end of the storage capacitor Cs is connected to the gate of the drive transistor T3. The other end of the storage capacitor Cs is connected to the source of an n-channel selection transistor T1 whose drain is connected to the data line DL. Further, the other end of the storage capacitor Cs is connected to the drain of the n-channel source control transistor T5, and the source of the drive control transistor is connected to the source of the drive control transistor T4 and the anode of the organic EL element EL. .

  A gate line GL is connected to the gates of the write control transistor T2 and the selection transistor T1, and a light emission set line ES is connected to the gates of the drive control transistor T4 and the source control transistor T5.

  Next, the operation of such a pixel circuit will be described with reference to FIG.

(I) Light emission In this state, the organic EL element EL emits light with a drive current corresponding to the previous data writing. The gate line GL is set to L level and the light emission set line ES is set to H level. Therefore, the selection transistor T1 and the write control transistor T2 are off, and the drive control transistor T4 and the source control transistor T5 are on. Therefore, according to the voltage held in the holding capacitor Cs in the previous write operation, a drive current flows through the drive transistor T3, which is supplied to the organic EL element EL, and the organic EL element EL emits light.

(Ii) Blocking The light emission set line ES is set to L level (0 V), and the drive control transistor T4 and the source control transistor T5 are turned off. Thereby, the connection side (the voltage here is Vn) of the storage capacitor Cs with the selection transistor T1 is cut off from both the PVDD and the organic EL element EL. As a result, the light emission of the organic EL element EL is stopped.

(Iii) Data Write The data voltage Vdata is set for the pixel on the data line DL. The data line DL is provided corresponding to each pixel of one horizontal line, and the data voltage Vdata is sequentially set to each data line DL. Therefore, the data voltage Vdata for each pixel is supplied to each pixel in a dot sequential manner.

  On the other hand, the gate line GL is set to the H level, and the selection transistor T1 and the write control transistor T2 are turned on. Therefore, the power supply voltage PVDD is supplied to the gate of the driving transistor T3, that is, one end of the holding capacitor Cs, and the data voltage Vdata is supplied to the other end of the holding capacitor Cs (Vn = Vdata). As a result, the voltage of | PVDD−Vdata | is charged in the storage capacitor Cs.

(Iv) Write end The gate line GL is set to L level, the selection transistor T1 and the write control transistor T2 are turned off, and the data write to the storage capacitor Cs is ended. Since the gate line GL is set to the L level while the light emission set line ES remains at the L level, the voltage held in the storage capacitor Cs can be determined without changing.

(V) Light emission The light emission set line ES is set to H level, and the drive control transistor T4 and the source control transistor T5 are turned on. As a result, one end of the storage capacitor Cs is connected to the gate of the drive transistor T3, and the other end is connected to the source of the drive transistor T3. The gate of the drive transistor T3 is | PVDD−Vdata | The voltage becomes high, and a drive current corresponding to the gate-source voltage flows to the drive transistor T3, which is supplied to the organic EL element EL. Therefore, the organic EL element EL emits light according to the voltage | PVDD−Vdata |.

  Here, in the conventional example of FIG. 3, a p-channel transistor is used as the drive transistor Td, and the data for driving the drive transistor Td is data whose luminance increases as it is lower than the power supply voltage. | PVDD−Vdata |. Therefore, in this embodiment, although an n-channel transistor is used as the driving transistor, an additional circuit for fixing the source potential is not necessary. Further, the data voltage having the same polarity as that of the conventional example can be used as the data voltage. Therefore, the conventional circuit for supplying the data voltage can be used as it is.

  Further, in the present embodiment, the driving transistor T3 is an n-channel transistor. An n-channel transistor has a smaller variation in threshold voltage than a p-channel transistor, and therefore can suppress display unevenness. Moreover, since the hysteresis in driving is small, the afterimage can be reduced. Furthermore, in this embodiment, all transistors are n-channel. Therefore, it is possible to obtain an effect that the fabrication is easy and the transistor characteristics are good.

  Further, there are only two control lines used in the present embodiment: the gate line GL and the light emission set line ES. Therefore, the timing signal can be easily created. In particular, both signals are signals corresponding to approximately one horizontal period, and a vertical transfer signal CKV that has been widely used in organic EL panels from the past and an enable signal ENB that is necessary for preventing malfunction during data switching are used. Can be created easily.

  Note that transistors other than the drive transistor T3 can be p-channel. Further, although the transistors are controlled by the two control lines of the gate line GL and the light emission set line ES, it is also possible to provide control lines individually.

  Moreover, as a light emitting element, if it is a current drive type, inorganic EL, other LED, etc. can be utilized.

It is a figure which shows the structure of embodiment. It is a timing chart explaining operation of an embodiment. It is a figure which shows the structure of a prior art example.

Explanation of symbols

  T1 selection transistor, T2 write control transistor, T3 drive transistor, T4 drive control transistor, T5 source control transistor, Cs holding capacitor, GL gate line, ES light emission set line, PVDD power supply line.

Claims (10)

  1. A light emitting element that emits light by a drive current;
    An n-channel driving transistor for supplying a driving current from a power source to the EL element;
    A write control transistor for controlling the connection between the gate of the drive transistor and the power source;
    A holding capacitor having one end connected to the gate of the driving transistor;
    A selection transistor for supplying a data voltage to the other end of the storage capacitor;
    A source control transistor for turning on and off the connection between the other end of the storage capacitor and the source of the driving transistor;
    A drive control transistor for turning on and off the drive current of the light emitting element;
    Have
    With the source control transistor and the drive control transistor turned off, by turning on the selection transistor and the write control transistor, the storage capacitor is charged with a power supply voltage and a data voltage difference,
    By turning off the selection transistor and the write control transistor, and turning on the source control transistor and the drive control transistor, a charging voltage of the storage capacitor is applied between the gate and source of the drive transistor, so that the power supply voltage and the data voltage A light emitting circuit characterized in that a driving current corresponding to the difference is generated in a driving transistor, thereby causing a light emitting element to emit light.
  2. The circuit of claim 1, wherein
    The light emitting circuit according to claim 1, wherein the selection transistor and the writing control transistor have the same polarity and are turned on and off by the same control voltage.
  3. The circuit according to claim 1 or 2,
    A light emitting circuit, wherein a source control transistor and a drive control transistor have the same polarity and are turned on and off by the same control voltage.
  4. The circuit according to any one of claims 1 to 3,
    The light emitting circuit, wherein the source control transistor, the drive control transistor, the write control transistor, and the selection control transistor are all n-channel transistors.
  5. In the circuit according to any one of claims 1 to 4,
    The drive control transistor is disposed between a source of the drive transistor and a light emitting element, and a connection portion between the light emitting element and the drive control transistor is connected to the other end of the source control transistor. Light emitting circuit.
  6. A light-emitting display device in which pixels for display are arranged in a matrix,
    Each pixel is
    A light emitting element that emits light by a drive current;
    An n-channel driving transistor for supplying a driving current from a power source to the light emitting element;
    A write control transistor for controlling the connection between the gate of the drive transistor and the power source;
    A holding capacitor having one end connected to the gate of the driving transistor;
    A selection transistor for supplying a data voltage from a data line to the other end of the storage capacitor;
    A source control transistor for turning on and off the connection between the other end of the storage capacitor and the source of the driving transistor;
    A drive control transistor for turning on and off the drive current of the light emitting element;
    Have
    With the source control transistor and the drive control transistor turned off, by turning on the selection transistor and the write control transistor, the storage capacitor is charged with a power supply voltage and a data voltage difference,
    By turning off the selection transistor and the write control transistor, and turning on the source control transistor and the drive control transistor, a charging voltage of the storage capacitor is applied between the gate and source of the drive transistor, so that the power supply voltage and the data voltage A light-emitting display device characterized in that a drive current corresponding to the difference is generated in a drive transistor, thereby causing a light-emitting element to emit light.
  7. The circuit of claim 6 wherein:
    The selection transistor and the write control transistor have the same polarity, and are turned on / off by a selection line that controls the selection transistor and the write control transistor of each pixel connected to the control line by one control line Display device.
  8. The circuit according to claim 6 or 7,
    The light emitting display device, wherein the source control transistor and the drive control transistor have the same polarity, and the source control transistor and the drive control transistor of each pixel connected to the control line are turned on and off by one control line.
  9. The circuit according to any one of claims 6 to 8,
    The light emitting display device, wherein the source control transistor, the drive control transistor, the write control transistor, and the selection transistor are all n-channel transistors.
  10. The circuit according to any one of claims 6 to 9,
    The drive control transistor is disposed between a source of the drive transistor and a light emitting element, and a connection portion between the light emitting element and the drive control transistor is connected to the other end of the source control transistor. Luminescent display device.
JP2005092619A 2005-03-28 2005-03-28 Light emitting circuit and light emitting display apparatus Pending JP2006276254A (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
JP2005092619A JP2006276254A (en) 2005-03-28 2005-03-28 Light emitting circuit and light emitting display apparatus

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
JP2005092619A JP2006276254A (en) 2005-03-28 2005-03-28 Light emitting circuit and light emitting display apparatus

Publications (1)

Publication Number Publication Date
JP2006276254A true JP2006276254A (en) 2006-10-12

Family

ID=37211110

Family Applications (1)

Application Number Title Priority Date Filing Date
JP2005092619A Pending JP2006276254A (en) 2005-03-28 2005-03-28 Light emitting circuit and light emitting display apparatus

Country Status (1)

Country Link
JP (1) JP2006276254A (en)

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2011175275A (en) * 2008-10-07 2011-09-08 Panasonic Corp Image display device and method of controlling the same

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2011175275A (en) * 2008-10-07 2011-09-08 Panasonic Corp Image display device and method of controlling the same
US8749454B2 (en) 2008-10-07 2014-06-10 Panasonic Corporation Image display device and method of controlling the same

Similar Documents

Publication Publication Date Title
US9728123B2 (en) Organic light emitting display device and method of driving the same
JP5538477B2 (en) Image display device and driving method thereof
JP5611312B2 (en) Organic light emitting diode display device and driving method thereof
US20180130412A1 (en) Pixel circuit, driving method therefor, and display device
US8913090B2 (en) Pixel circuit, organic electro-luminescent display apparatus, and method of driving the same
US8902138B2 (en) Organic light emitting diode display device and method of driving the same
JP5070266B2 (en) Pixel and organic light emitting display using the same
US7898509B2 (en) Pixel circuit, display, and method for driving pixel circuit
US8581807B2 (en) Display device and pixel circuit driving method achieving driving transistor threshold voltage correction
US8723763B2 (en) Threshold voltage correction for organic light emitting display device and driving method thereof
KR100859424B1 (en) Active matrix type display apparatus, active matrix type organic electroluminescence display apparatus, and driving methods thereof
US9418597B2 (en) Pixel, display device and driving method thereof
JP5352101B2 (en) Display panel
JP5612988B2 (en) Pixel for organic electroluminescent display device and organic electroluminescent display device using the same
WO2016045283A1 (en) Pixel driver circuit, method, display panel, and display device
JP4501429B2 (en) Pixel circuit and display device
US7999770B2 (en) Electro-optical device, method of driving electro-optical device, and electronic apparatus
JP5330643B2 (en) Organic electroluminescence display
US7619594B2 (en) Display unit, array display and display panel utilizing the same and control method thereof
KR100602363B1 (en) Emission driver and light emitting display for using the same
JP5115180B2 (en) Self-luminous display device and driving method thereof
JP5176522B2 (en) Self-luminous display device and driving method thereof
JP5382985B2 (en) Organic electroluminescent display device and driving method thereof
WO2017080379A1 (en) Pixel compensation circuit and driving method therefor, array substrate, and display device
US7327357B2 (en) Pixel circuit and light emitting display comprising the same