JP2006284716A - Display driving device and its driving control method, and display device and its driving control method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a display driving device and its driving control method that can drive a light emitting element to emit light with proper luminance gradations corresponding to display data by supplying a light emission driving current having a current value corresponding to the display data and then to provide a display device whose display picture quality is excellent and homogeneous and its driving control method. <P>SOLUTION: The display driving device 100 is equipped with a detection voltage ADC 140 which measures the threshold voltage of a light emission driving transistor provided to each display pixel PX (light emission driving circuit DC) at least in a threshold voltage detection period Tdec, a frame memory 170 which stores a measured threshold voltage for each display pixel PX, a compensation voltage DAC 150 which applies a precharge voltage based upon the measured threshold voltage to the display pixel PX in a display driving period Tcyc, and a gradation signal generation part 130 which generates a gradation signal corresponding to the display data and applies the signal to the display pixel PX. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a display drive device and a drive control method thereof, and a display device and a drive control method thereof, and more particularly, a current drive type that emits light at a predetermined luminance gradation by supplying a current according to display data (or Display control device applicable to a display panel (display pixel array) in which a plurality of (light-current control type) light-emitting elements are arranged, a drive control method thereof, a display device including the display drive device, and a display device therefor The present invention relates to a drive control method.

  In recent years, display devices that are light and thin and have low power consumption have been widely used as monitors and displays for personal computers and video equipment. In particular, a liquid crystal display device (LCD) is widely applied as a display device for portable devices (mobile devices) such as mobile phones, digital cameras, personal digital assistants (PDAs), and electronic dictionaries that have been popular in recent years.

  As a next-generation display device following such a liquid crystal display device, an organic electroluminescence element (organic EL element), an inorganic electroluminescence element (inorganic EL element), or a light emitting element such as a light emitting diode (LED) (self Research and development for full-scale popularization of light-emitting element type display devices (light-emitting element type displays) having a display panel in which light-emitting optical elements) are arranged in a matrix are actively performed.

  In particular, a light-emitting element type display using an active matrix driving method has a higher display response speed than the above-described liquid crystal display device, and has no viewing angle dependency, and has high luminance and high contrast, and display image quality. A feature that is extremely advantageous for application to portable devices that enables high definition, etc., and does not require a backlight like a liquid crystal display device, and can be further reduced in thickness and weight and power consumption. have.

  In such a light emitting element type display, various drive control mechanisms and control methods for controlling the operation (light emission state) of the light emitting element have been proposed. For example, Patent Document 1 discloses a drive circuit (light emission drive circuit) including a plurality of switching elements for controlling light emission of the light emitting elements in addition to the light emitting elements, for each display pixel constituting the display panel. A configuration with is described.

  FIG. 27 is a schematic configuration diagram showing a main part of a voltage-controlled active matrix light-emitting element type display in the prior art, and FIG. 28 shows display pixels (light emission drive circuit and light-emitting element applicable to the light-emitting element type display in the prior art. FIG. Here, FIG. 28 shows a circuit configuration of a display pixel including an organic EL element as a light emitting element.

  As shown in FIG. 27, the active matrix organic EL display device described in Patent Document 1 generally includes a plurality of scanning lines (selection lines; Y-direction signal lines) SLp arranged in the row and column directions. A display panel 110P in which a plurality of display pixels EMp are arranged in a matrix in the vicinity of each intersection of data lines (signal lines; X direction signal lines) DLp, and a scanning driver (Y direction peripheral driving) connected to each scanning line SLp. Circuit) 120P and a data driver (X-direction peripheral drive circuit) 130P connected to each data line DL.

  As shown in FIG. 28, each display pixel EMp has a thin film transistor (TFT) Tr111 having a gate terminal connected to the scanning line SLp, a source terminal and a drain terminal connected to the data line DL and a contact N111, and a gate terminal. A light emission driving circuit DCp including a thin film transistor Tr112 connected to the contact N111 and having a source terminal applied with a predetermined power supply voltage Vdd; and an anode terminal connected to a drain terminal of the thin film transistor Tr112 of the light emission driving circuit DCp; An organic EL element (current control type light emitting element) OEL to which a ground potential Vgnd lower than the power supply voltage Vdd is applied to the cathode terminal is configured. In FIG. 28, Cp is a capacitor formed between the gate and source of the thin film transistor Tr112.

  In the display device including the display panel 110P including the display pixel EMp having such a configuration, first, the scan driver 120P sequentially applies the on-level scan signal voltage Ssel to the scan lines SLp of each row, The thin film transistor Tr111 of the display pixel EMp (light emission drive circuit DCp) for each row is turned on, and the display pixel EMp is set to the selected state.

  In synchronization with the selection timing, the gradation voltage Vpix corresponding to the display data is applied to the data line DLp of each column by the data driver 130P, thereby passing through the thin film transistor Tr111 of each display pixel EMp (light emission drive circuit DCp). A potential corresponding to the gradation voltage Vpix is applied to the contact N111 (that is, the gate terminal of the thin film transistor Tr112).

  As a result, the thin film transistor Tr112 is turned on in a conduction state (that is, a conduction state according to the gradation voltage Vpix) corresponding to the potential of the contact N111 (strictly, the potential difference between the gate and the source), and from the power supply voltage Vdd. A predetermined light emission drive current flows to the ground potential Vgnd via the thin film transistor Tr112 and the organic EL element OEL, and the organic EL element OEL emits light with a luminance gradation corresponding to display data (gradation voltage Vpix).

  Next, by applying an off-level scanning signal voltage Ssel to the scanning line SLp from the scanning driver 120P, the thin film transistor Tr111 of the display pixel EMp for each row is turned off, and the display pixel EMp is set to a non-selected state. The data line DLp and the light emission drive circuit DCp are electrically disconnected. At this time, the potential applied to the gate terminal (contact N111) of the thin film transistor Tr112 is held in the capacitor Cp, whereby a predetermined voltage is applied between the gate and the source of the thin film transistor Tr112, and the thin film transistor Tr112 is turned on. continue.

  Therefore, similarly to the light emission operation in the selected state, a predetermined light emission drive current flows from the power supply voltage Vdd to the organic EL element OEL via the thin film transistor Tr112, and the light emission operation is continued. This light emission operation is controlled so as to continue, for example, for one frame period until the gradation voltage Vpix corresponding to the next display data is applied (written) to the display pixel EMp of each row.

  In such a drive control method, the organic EL element OEL is adjusted by adjusting the voltage value of the gradation voltage Vpix applied to each display pixel EMp (specifically, the gate terminal of the thin film transistor Tr112 of the light emission drive circuit DCp). This is called a voltage gradation designation method (or voltage gradation designation drive) because the light emission driving current is controlled to emit light at a predetermined luminance gradation.

JP-A-8-330600 (Page 3, FIG. 4)

However, the display device provided with the light emission drive circuit corresponding to the voltage gradation designation method as described above in each display pixel has the following problems.
That is, in the light emission drive circuit DCp as shown in FIG. 28, a light emission drive thin film transistor in which a current path is connected in series to the organic EL element OEL and a light emission drive current according to display data (gradation voltage) flows. When the element characteristics (particularly the threshold voltage characteristics) of the Tr 112 change (shift) depending on the usage time, driving history, etc., the light emission that flows between the gate voltage (the potential of the contact 111) and the source-drain Since the relationship with the drive current (source-drain current) changes and the current value of the light emission drive current flowing at a predetermined gate voltage fluctuates (for example, decreases), appropriate luminance according to the display data There has been a problem that it is difficult to stably realize a light emitting operation at a gradation over a long period of time.

  Further, when the element characteristics (threshold voltage) of the thin film transistors Tr111 and Tr112 in the display panel 110P vary for each display pixel EMp (light emission drive circuit DCp), or for each display panel 110P depending on the manufacturing lot, When the element characteristics of Tr111 and Tr112 vary, the current value of the light emission drive current for each display pixel or each display panel in the voltage gradation designation type light emission drive circuit as described above. As a result, there is a problem that proper gradation control cannot be performed and a display device having a uniform display image quality cannot be provided.

  Accordingly, in view of the above-described problems, the present invention drives a light emitting element to emit light at an appropriate luminance gradation according to display data by supplying a light emission driving current having an appropriate current value corresponding to display data. It is an object of the present invention to provide a display driving device and a driving control method thereof, and to provide a display device having a good and uniform display image quality and a driving control method thereof.

  According to the first aspect of the present invention, a gradation signal is supplied to a display pixel including a current-controlled light-emitting element and a light-emitting drive element that supplies a light-emission driving current to the light-emitting element. In a display driving device that emits light at a luminance gradation of at least one, a gradation signal generating unit that generates at least the gradation signal and supplies the gradation signal to the display pixel, and a light emission driving element provided in the display pixel Threshold voltage detecting means for detecting the threshold voltage, storage means for storing threshold data associated with the threshold voltage detected by the threshold voltage detecting means, and the storage means Compensation voltage applying means for applying a compensation voltage for compensating the threshold voltage of the light emission driving element to the light emission driving element based on the threshold data stored in the light emission driving element.

  According to a second aspect of the present invention, in the display driving device according to the first aspect, the display driving device detects a threshold detection voltage having a potential higher than the threshold voltage to the light emitting driving element. And a threshold voltage detection means, wherein the threshold voltage detection voltage is applied to the light emission drive element, and a charge corresponding to the threshold voltage detection voltage is applied. A voltage after being partially discharged and converged is detected as the threshold voltage of the light emission drive element.

  According to a third aspect of the present invention, in the display driving device according to the first or second aspect, the compensation voltage applying unit is configured to add the light emitting driving element to the light emitting driving element based on the threshold value data stored in the storage unit. The compensation voltage for holding a voltage component corresponding to a threshold voltage is generated and applied to the light emission driving element.

  According to a fourth aspect of the present invention, in the display driving device according to the second or third aspect, the light emission driving element provided in the display pixel includes a current path for passing the light emission driving current to the light emitting element, and the light emission driving current. The detection voltage applying means applies the threshold detection voltage between the control terminal of the light emission driving element and one end side of the current path. The threshold voltage detecting means detects a potential difference between the control terminal of the light emission drive element and one end side of the current path as the threshold voltage.

  According to a fifth aspect of the present invention, in the display driving device according to the fourth aspect, the compensation voltage applying means is stored in the storage means between the control terminal of the light emission driving element and one end side of the current path. The compensation voltage based on the threshold data is applied.

  According to a sixth aspect of the present invention, in the display driving device according to any one of the first to fifth aspects, the threshold voltage detecting means digitally calculates the threshold voltage of the light emission driving element detected as an analog signal. Means for converting into a signal is provided, and the storage means stores the threshold voltage converted into the digital signal as the threshold data.

  According to a seventh aspect of the present invention, in the display driving device according to the sixth aspect, the compensation voltage applying means is configured to generate the light emitting driving element based on the threshold data stored as a digital signal in the storage means. A means for generating the compensation voltage comprising an analog signal for compensating the threshold voltage is provided.

  According to an eighth aspect of the present invention, in the display driving device according to any one of the first to seventh aspects, the gradation signal generating means emits the light emitting element with a predetermined luminance gradation as the gradation signal. Means for generating a gray-scale current having a predetermined current value.

According to a ninth aspect of the present invention, in the display driving device according to any one of the first to eighth aspects, the gradation signal generating means is a predetermined signal for causing the light emitting element to perform a non-light emission operation as the gradation signal. Means is provided for generating a non-light emitting display voltage having a voltage value.
A tenth aspect of the present invention is the display driving device according to any one of the first to ninth aspects, wherein the display driving device outputs the gradation signal to the plurality of display pixels provided in a predetermined arrangement. Further comprising data acquisition means for sequentially capturing and holding luminance gradation data for generating the gradation signal generation means for each of the plurality of display pixels held in the data acquisition means. The gradation signal corresponding to luminance gradation data is generated, and the gradation signal is supplied to each of the plurality of display pixels.

  An eleventh aspect of the present invention is the display driving device according to any one of the first to tenth aspects, wherein the display driving device detects the threshold value detected from a plurality of the display pixels provided in a predetermined arrangement. Threshold value acquisition means for individually capturing and sequentially transferring the threshold value data associated with the voltage; and the storage means for each of the plurality of display pixels transferred from the threshold value acquisition means The threshold value data associated with the threshold voltage is individually stored in association with each of the plurality of display pixels.

  According to a twelfth aspect of the present invention, in the display drive device according to the eleventh aspect, the data acquisition unit and the threshold value acquisition unit individually fetch the luminance gradation data sequentially, and the threshold value data A configuration of individually capturing and sequentially transferring is shared.

  A thirteenth aspect of the present invention is the display driving device according to any one of the first to twelfth aspects, wherein the display driving device at least sets the threshold voltage of the display pixel by the threshold voltage detecting means. A signal path for detecting, a signal path for applying the compensation voltage to the display pixel by the compensation voltage applying means, a signal path for supplying the gradation signal to the display pixel by the gradation signal generating means, and the display Signal path switching means for selectively switching control of connection with a single data line provided corresponding to a pixel is provided.

  According to a fourteenth aspect of the present invention, in the display driving device according to the thirteenth aspect, the display driving device further applies a signal for detecting the threshold voltage to the display pixel by the detection voltage applying unit. Is configured to be selectively connected to the single data line.

  According to a fifteenth aspect of the present invention, a gradation signal is supplied to a display pixel that includes a current-controlled light-emitting element and a light-emitting drive element that supplies a light-emission driving current to the light-emitting element, whereby the light-emitting element is predetermined. In a drive control method for a display driving device that performs light emission operation at a luminance gradation of at least, a threshold voltage unique to the light emission driving element is detected, and storage means is stored as threshold data associated with the threshold voltage And a second step of applying a compensation voltage for compensating the threshold voltage of the light emission drive element to the light emission drive element based on the threshold data stored in the storage means. The gradation signal is supplied to the display pixel, and the voltage component based on the gradation signal is added to and held on the voltage component based on the compensation voltage applied to the light emitting drive element. A third step that, characterized in that it comprises a.

  According to a sixteenth aspect of the present invention, in the drive control method for a display driving device according to the fifteenth aspect, the first step is executed at an arbitrary timing prior to the second step and the third step. Features.

  According to a seventeenth aspect of the present invention, in the drive control method for a display driving device according to the fifteenth or sixteenth aspect, the first step is a threshold value detection of a potential higher than the threshold voltage in the light emission driving element. And a step of detecting, as the threshold voltage of the light emitting drive element, a voltage after a part of the charge corresponding to the threshold voltage detection voltage is discharged and converged It is characterized by including these.

According to an eighteenth aspect of the present invention, in the display driver driving control method according to the seventeenth aspect, the first step converts the threshold voltage of the light emission driving element detected as an analog signal into a digital signal. And storing the threshold value data in the storage means.
According to a nineteenth aspect of the present invention, in the drive control method for a display driving device according to any one of the fifteenth to eighteenth aspects, the second step is based on the threshold value data stored in the storage means. A voltage that compensates for the threshold voltage of the light emission drive element is generated and applied to the light emission drive element as the compensation voltage.

  According to a twentieth aspect of the present invention, in the drive control method for a display driving device according to the eighteenth or nineteenth aspect, the second step is based on the threshold value data stored as a digital signal in the storage unit. The compensation voltage including an analog signal for compensating the threshold voltage of the light emitting drive element is generated.

  In accordance with a twenty-first aspect of the present invention, in the drive control method for a display driving device according to any of the fifteenth to twentieth aspects, the third step is performed when the light-emitting element is caused to emit light at a predetermined luminance gradation. Generates a gray-scale current having a predetermined current value as the gray-scale current, and generates a non-light-emitting display voltage having a predetermined voltage value as the gray-scale signal when the light-emitting element is operated without light emission. And supplying to the display pixels.

  According to a twenty-second aspect of the present invention, in the drive control method for a display driving device according to any of the fifteenth to twenty-first aspects, at least the first step applies the threshold detection voltage to the display pixel. An operation for detecting the threshold voltage of the display pixel in the first step, an operation for applying the compensation voltage to the display pixel in the second step, and a step in the third step. The operation of supplying the gradation signal to the display pixel is selectively executed via a single data line provided corresponding to the display pixel.

  According to a twenty-third aspect of the present invention, there is provided a current control type light emitting element and a light emitting driving element for supplying a light emitting driving current to the light emitting element at each intersection of a plurality of selection lines and data lines arranged in a row direction and a column direction. A display device including a display panel in which a plurality of display pixels are arranged, and a selection signal is sequentially applied to the display pixels for each row of the display panel at a predetermined timing to select a selection state A drive unit; and a data drive unit that generates a gradation signal according to display data for displaying desired image information and supplies the grayscale signal to the display pixels in a row set in the selected state. The drive unit includes at least a gradation signal generation unit that individually supplies the gradation signal to each of the display pixels via the data line, and a threshold value specific to the light emission drive element of each display pixel. Individual voltage check Threshold voltage detection means, storage means for storing threshold data associated with the threshold voltage detected by the threshold voltage detection means for each display pixel, and storage means Compensation voltage applying means for individually applying a compensation voltage for compensating the threshold voltage for each display pixel to the light emitting drive element of the display pixel based on the stored threshold data. It is characterized by that.

  According to a twenty-fourth aspect of the present invention, in the display device according to the twenty-third aspect, the data driving unit applies a threshold detection voltage higher than the threshold voltage to the light emitting driving element of the display pixel. And a detection voltage applying unit that individually applies the threshold voltage detection unit, wherein the threshold voltage detection unit individually sets the threshold voltage of the light emitting drive element after the threshold voltage detection voltage has converged. It is characterized by detecting.

  According to a twenty-fifth aspect of the present invention, in the display device according to the twenty-third or twenty-fourth aspect, the compensation voltage applying means applies the threshold to the light emission driving element based on the threshold value data stored in the storage means. The compensation voltage for holding the voltage component corresponding to the value voltage is generated and applied individually to the light emission drive element of the display pixel.

  According to a twenty-sixth aspect of the present invention, in the display device according to the twenty-fourth or twenty-fifth aspect, the light emission driving element provided in each of the display pixels includes a current path through which the light emission driving current flows to the light emitting element, and the light emission driving. A control terminal for controlling a current supply state, wherein the detection voltage applying means applies the threshold detection voltage between the control terminal of the light emission drive element and one end of the current path; The threshold voltage detection means uses the potential difference between the control terminal of the light emission drive element and one end side of the current path when no current flows in the current path as the threshold voltage. It is characterized by detecting.

  According to a twenty-seventh aspect of the present invention, in the display device according to the twenty-sixth aspect, the compensation voltage applying unit is stored in the storage unit between the control terminal of the light emission driving element and one end side of the current path. Further, the compensation voltage based on the threshold data is applied.

  A twenty-eighth aspect of the present invention is the display device according to any of the twenty-third to twenty-seventh aspects, wherein the threshold voltage detecting means outputs a threshold voltage of the light emission driving element detected as an analog signal to a digital signal. Means for generating the threshold value data, and the compensation voltage applying means is based on the threshold data stored as a digital signal in the storage means. Means for generating the compensation voltage comprising an analog signal for compensating the threshold voltage is provided.

  According to a twenty-ninth aspect of the present invention, in the display device according to any one of the twenty-third to twenty-eighth aspects, the gradation signal generating means causes the light emitting element to emit light at a predetermined luminance gradation as the gradation signal. Means for generating a gradation current having a predetermined current value, and means for generating a non-light emitting display voltage having a predetermined voltage value for causing the light emitting element to perform a non-light emitting operation. And

  In a thirty-third aspect of the present invention, in the display device according to any one of the twenty-third to thirty-ninth aspects, the data driving unit is configured to associate the threshold voltage associated with the threshold voltage detected from each display pixel. Threshold acquisition means for individually capturing and sequentially transferring value data, and data for sequentially capturing and holding luminance gradation data for generating the gradation signal for each of the display pixels. Acquisition means, and the storage means stores the threshold data associated with the threshold voltage for each of the plurality of display pixels transferred from the threshold acquisition means. The gradation signal generation means generates the gradation signal corresponding to the luminance gradation data for each of the plurality of display pixels held in the data acquisition means. And, for each of the plurality of display pixels, and supplying the gradation signal.

  The invention according to claim 31 is the display device according to claim 30, wherein the data acquisition means and the threshold value acquisition means individually take in the luminance gradation data individually, and the threshold value data individually. And the configuration for sequentially transferring the data to each other is shared.

  According to a thirty-second aspect of the present invention, in the display device according to any one of the twenty-third to thirty-first aspects, the data driver detects at least the threshold voltage of the display pixel by the threshold voltage detecting means. A signal path for applying the compensation voltage to the display pixel by the compensation voltage applying means, a signal path for supplying the gradation signal to the display pixel by the gradation signal generating means, and the display pixel And a signal path switching means for selectively switching control of connection with a single data line provided corresponding to.

  According to a thirty-third aspect of the present invention, in the display device according to the thirty-second aspect, the data driver further includes a signal path for applying the threshold detection voltage to the display pixel by the detection voltage applying unit. The single data line is configured to be selectively connected to the single data line.

  The invention according to Claim 34 is the display device according to any one of Claims 23 to 33, wherein the display device further includes a power supply driving unit that applies a predetermined supply voltage to each of the display pixels, The power supply driving unit sequentially applies the supply voltage to the display pixels for each row of the display panel at a predetermined timing, and sets the display pixels in a light emitting operation state for each row.

  The invention according to claim 35 is the display device according to any one of claims 23 to 33, wherein the display device further includes a power supply driving unit that applies a predetermined supply voltage to each of the display pixels, The power supply driver sequentially applies the supply voltage at a predetermined timing to the display pixels of each group obtained by grouping the plurality of display pixels arranged in the display panel into a plurality of rows, Each of the display pixels is set to a light emitting operation state.

  A thirty-sixth aspect of the present invention is the display device according to any one of the twenty-third to thirty-fifth aspects, wherein each of the display pixels includes a light emission driving circuit that controls a light emitting operation of the light emitting element. At least one end of the current path is applied with the supply voltage, and the other end of the current path is connected with a connection contact with the light emitting element, and a control terminal is connected to the selection line, The supply voltage is applied to one end of the current path, the second switch means in which the control terminal of the first switch means is connected to the other end of the current path, the control terminal is connected to the selection line, and the current A third switch means having the data line connected to one end of the path and the connection contact connected to the other end of the current path, and the light emission drive element is the first switch means, The detection voltage applying means is a front A voltage for threshold detection is applied between the control terminal of the first switch means and the connection contact, and the threshold voltage detection means is connected to the control terminal of the first switch means. The potential between the connection contacts is detected as the threshold voltage, and the compensation voltage application means is stored in the storage means between the control terminal of the first switch means and the connection contact. The compensation voltage based on the threshold data is applied.

A thirty-seventh aspect of the present invention is the display device according to the thirty-sixth aspect, wherein the first to third switch means are field effect transistors each including a semiconductor layer made of amorphous silicon.
According to a thirty-eighth aspect of the present invention, in the display device according to any one of the twenty-third to thirty-seventh aspects, the light emitting element is an organic electroluminescent element.

  According to a thirty-ninth aspect of the present invention, there is provided a display panel in which a plurality of display pixels each having a current control type light emitting element are arranged at each intersection of a plurality of selection lines and data lines arranged in a row direction and a column direction. , A selection driver that sequentially applies a selection signal to the display pixels for each row of the display panel at a predetermined timing to set the selection state, and a gradation corresponding to display data for displaying desired image information A data driver that generates a signal and supplies the signal to the display pixels in the row set in the selected state, and supplies the grayscale signal to each of the display pixels by the data driver, In a drive control method for a display device that causes a display pixel to emit light at a predetermined luminance gradation and displays the desired image information on the display panel, at least provided for each of the display pixels, Base A threshold detection voltage having a higher potential than a threshold voltage specific to the light emission drive element is individually applied to the light emission drive element that supplies the light emission drive current having a predetermined current value to the light emission element. A threshold voltage associated with the threshold voltage by individually detecting the threshold voltage of the light-emitting drive element after the detection voltage application step and the threshold voltage detection voltage have converged; Based on the threshold voltage detection step for storing each display pixel in the storage unit as data, and the threshold data stored in the storage unit, the data of the light emission driving element for each display pixel is stored. A compensation voltage generation step for generating a compensation voltage for compensating the threshold voltage, individually applying the compensation voltage to the light emitting drive element and holding the compensation voltage as a voltage component, and the gradation signal corresponding to the display data are displayed on the display screen. A data writing step of supplying the voltage component based on the gradation signal to the voltage component based on the compensation voltage applied to the light emission driving element and holding the data component, and light emission of each display pixel A gradation light emitting step of supplying the light emission driving current generated based on the voltage component held in the driving element to each of the light emitting elements, and causing the light emitting element to emit light at a predetermined luminance gradation; It is characterized by including.

  40. The display device drive control method according to claim 39, wherein the detection voltage applying step and the threshold voltage detecting step include the compensation voltage applying step, the data writing step, It is performed on all the display pixels arranged on the display panel at an arbitrary timing prior to the gradation light emission step.

The invention according to claim 41 is the drive control method for a display device according to claim 40, wherein the detection voltage applying step and the threshold voltage detecting step are performed on the display pixels arranged in the display panel. These are executed sequentially for each row.
The invention according to claim 42 is the drive control method for the display device according to claim 39, wherein the compensation voltage applying step and the data writing step are performed on the plurality of display pixels arranged in the display panel. The gradation light emission step is sequentially executed for each row, and is sequentially executed from the row where the compensation voltage applying step and the data writing step are completed.

  According to a forty-third aspect of the present invention, in the display device drive control method according to the thirty-ninth aspect, in the compensation voltage applying step and the data writing step, the plurality of display pixels arranged in the display panel are arranged in a plurality of rows. The gradation light emission step is sequentially executed from the group after the completion of the compensation voltage applying step and the data writing step.

  According to a 44th aspect of the present invention, in the display device drive control method according to any of the 39th to 43rd aspects, the data writing step is performed when the light emitting element is caused to emit light at a predetermined luminance gradation. In the case where a gradation current having a predetermined current value is supplied to the display pixel as the gradation signal and the light emitting element is operated without emitting light, a non-light emitting display voltage having a predetermined voltage value as the gradation signal Is supplied to the display pixel.

  A 45th aspect of the present invention is the display device drive control method according to any of the 39th to 44th aspects, wherein at least the detection voltage application step, the threshold voltage detection step, and the compensation voltage application. The step and the data writing step are selectively executed through a single data line provided corresponding to each of the display pixels.

  According to the display drive device and the drive control method thereof according to the present invention, prior to the gradation signal writing operation to the display pixel and the light emission operation of the display pixel (light emitting element), first, A threshold voltage specific to a switching element (thin film transistor) for driving light emission provided in the light emission driving circuit is detected, and a voltage component corresponding to the threshold voltage is applied to the switching element based on the threshold detection data. Even when the threshold voltage of the switching element (thin film transistor) is changed (Vth shift) due to a change over time, a drive history, or the like by performing a precharge operation for holding (accumulating charges) Since the switching device can hold an appropriate voltage component according to the gradation signal, the light emitting element (organic EL element) can emit light at an appropriate luminance gradation. It can be.

  Further, in this case, prior to the gradation signal writing operation, the voltage component corresponding to the threshold voltage inherent to the switching element can be held and set in the boundary region of the on / off operation. When the light emitting element is operated to emit light with low gradation luminance, the above threshold is applied even when a gradation signal (gradation current) having a minute current value corresponding to the luminance gradation is supplied. By adding only the voltage component corresponding to the gradation current to the voltage component corresponding to the value voltage and holding (charging), the voltage component (effective voltage) corresponding to the gradation signal can be quickly held. Occurrence of insufficient writing can be suppressed.

  Further, in the non-light-emitting display not accompanied by the light-emitting operation of the light-emitting element, by applying a non-light-emitting display voltage having a predetermined voltage value as a gradation signal, the above-described pre-charge operation switching element for light emission driving Since the voltage component (charge) held in the capacitor can be discharged and set to a voltage sufficiently lower than the threshold voltage, the switching element is not turned on under the influence of slight voltage fluctuations. The light emitting element can be satisfactorily held in a non-light emitting state (black display state).

  Then, according to the display device and the drive control method thereof according to the present invention, by having the configuration in which the display drive device described above is applied to the data driver, the gradation signal writing operation to each display pixel, At any timing prior to the light emitting operation of the light emitting element, first, with respect to all the display pixels arranged in the display panel, the light emitting driving switching element (thin film transistor) provided in the display pixel (light emitting driving circuit) is used. A threshold voltage (threshold data) of a switching element detected in advance for each display pixel immediately before the writing operation of the display data to each display pixel is detected. Based on the above, it is possible to set a state in which each threshold voltage is compensated by holding a voltage component corresponding to the threshold voltage inherent in the switching element for each display pixel. Therefore, even when the threshold voltage of the switching element (thin film transistor) changes (Vth shift) due to a change over time, a drive history, or the like, the influence is suppressed, and a gradation is applied to the switching element. An appropriate voltage component corresponding to the signal can be held, and the light emitting element can be operated to emit light at an appropriate luminance gradation.

  In addition, in the gradation signal writing operation, a voltage component (charge) corresponding to the threshold voltage inherent to the switching element provided in each display pixel is already held, so that it corresponds to the gradation signal. Only the voltage component needs to be added and charged, and the voltage component based on the gradation signal can be quickly written, and the occurrence of insufficient writing can be suppressed.

Hereinafter, a display drive device and a drive control method thereof, and a display device and a drive control method thereof according to the present invention will be described in detail with reference to embodiments.
First, a display driving device and a driving control method applied to a display device according to the present invention will be described with reference to the drawings.

  FIG. 1 is a main part configuration diagram showing an embodiment of a display driving device according to the present invention and a display pixel driven and controlled by the display driving device. Here, the relationship between a specific display pixel arranged on the display panel of the display device and a display drive device that controls the light emission drive of the display pixel will be described.

<Display drive device>
As shown in FIG. 1, the display driving apparatus 100 according to the present embodiment generally includes a shift register / data register unit 110, a display data latch unit 120, a gradation signal generation unit 130, and a threshold detection voltage analog. -Digital converter (hereinafter abbreviated as "detection voltage ADC", and in the figure abbreviated as "Vth ADC") 140, and threshold compensation voltage digital-analog converter (hereinafter abbreviated as "compensation voltage DAC"). In the figure, it is expressed as “VthDAC”) 150, a threshold data latch unit (indicated as “Vth data latch part” in the figure) 160, a frame memory 170, and data line input / output switching. Part 180.

  The shift register / data register unit (data acquisition means, threshold value acquisition means) 110 is a shift register that sequentially outputs shift signals, not shown, and a digital signal supplied at least from the outside based on the shift signals And a data register for sequentially taking in luminance gradation data. More specifically, an operation of sequentially fetching display data (luminance gradation data) of display pixels PX for one row of the display panel, which is sequentially supplied from the outside, and transferring it to the display data latch unit 120 described later, or The threshold voltage (threshold detection data) of the display pixels PX for one row, which is converted into a digital signal by the detection voltage ADC 140 and held in the threshold data latch unit 160, is sequentially taken into a frame memory 170 to be described later. Either the transfer operation or the operation of sequentially fetching the threshold compensation data of the display pixels PX for one specific row from the frame memory 170 and transferring it to the threshold data latch unit 160 is selectively executed. Each of these operations will be described in detail later.

The display data latch unit 120 holds the display data (luminance gradation data) of the display pixels PX for one row that is taken in and transferred from the outside by the shift register / data register unit 110.
The gradation signal generation unit (gradation signal generation means) 130 is a gradation for causing the organic EL element (current-controlled light emitting element) OEL to perform a light emission operation or a non-light emission operation with a luminance gradation corresponding to display data. As a signal, a gray scale current Idata having a predetermined current value for causing the organic EL element OEL to emit light at a predetermined luminance gradation, or black display (the lowest luminance gradation) without causing the organic EL element OEL to emit light. ) For selectively setting one of the non-light emitting display voltages Vzero having a predetermined voltage value.

  Here, as a configuration for supplying a gray scale current having a current value corresponding to display data as a gray scale signal, for example, the display data is based on a gray scale reference voltage supplied from power supply means (not shown). A digital-analog converter (D / A converter) that converts a digital signal voltage of each display data held in the latch unit 120 into an analog signal voltage, and a gradation current Idata having a current value corresponding to the analog signal voltage A configuration including a voltage-current converter that generates

  In the following description, a case is described in which gradation display having a predetermined current value is supplied to each display pixel as a gradation signal to perform gradation display, but the present invention is not limited to this. Instead, a gradation signal having a voltage value corresponding to the display data may be applied as the gradation signal. In this case, for example, a configuration including only the digital-analog converter is provided. Can be applied.

  The detection voltage ADC (threshold voltage detection means) 140 is a threshold of a switching element (thin film transistor Tr13) that supplies a light emission driving current to a light emitting element (for example, an organic EL element OEL) provided in each display pixel PX described later. A value voltage (or a voltage component corresponding to the threshold voltage) is taken (measured) as an analog signal voltage and converted into threshold detection data composed of a digital signal voltage.

  A compensation voltage DAC (compensation voltage application means, detection voltage application means) 150 receives threshold compensation data including digital signal voltages for compensating the threshold voltage of the switching element provided in each display pixel PX. Then, it is converted into a precharge voltage (threshold compensation voltage) composed of an analog signal voltage. Further, as shown in a drive control method described later, in the operation of measuring the threshold voltage of the switching element by the detection voltage ADC 140 (threshold voltage detection operation), between the gate and the source of the thin film transistor constituting the switching element ( A predetermined detection voltage can be output so that a potential difference higher than the threshold voltage of the switching element is set (a voltage component is held) at both ends of the capacitor Cs.

  The threshold data latch unit 160 captures and holds threshold detection data converted and generated by the detection voltage ADC 140 for each display pixel PX for one row, and stores the threshold detection data. An operation of sequentially transferring to a frame memory 170 (to be described later) via the shift register / data register unit 110, or a threshold value for each display pixel PX for one row corresponding to the threshold detection data from the frame memory 170 One of the operations of sequentially acquiring and holding the compensation data and transferring the threshold compensation data to the compensation voltage DAC 150 is selectively executed.

  Further, the frame memory (storage means) 170 includes the detection voltage ADC 140 and the threshold data latch unit prior to the writing operation of the display data (luminance gradation data) to each display pixel PX arranged on the display panel. The threshold detection data based on the threshold voltage detected for each display pixel PX for one row by 160 is sequentially taken in via the shift register / data register unit 110 to display one display panel (one frame). Are stored individually for each display pixel PX, and the threshold detection data is used as threshold compensation data, or threshold compensation data corresponding to the threshold detection data is used as a shift register / data register. The data are sequentially output via the unit 110 and transferred to the threshold data latch unit 160 (compensation voltage DAC 150).

  The data line input / output switching unit (signal path switching means) 180 is a threshold of the switching element (thin film transistor) provided in each display pixel PX via the data line DL arranged in the column direction of the display panel. A voltage detection side switch 181 for taking the value voltage into the detection voltage ADC 140 and measuring it, and at least a precharge voltage for compensating the threshold voltage of the switching element provided in each display pixel PX, or For selecting a mode for supplying one of the gradation signals (gradation current or non-emission display voltage) for causing each display pixel PX to emit light at a luminance gradation corresponding to the display data. The input selection switch 182 and the precharge voltage or gradation signal selected by the input signal selection switch 182 are used as a data write. The writing side switch 183 to be supplied to the display pixels PX via the DL, and has a configuration with a.

  Here, the voltage detection side switch 181 and the write side switch 183 can be constituted by, for example, thin film transistors (field effect transistors) having different channel polarities, and as shown in FIG. A thin film transistor can be used, and an n-channel thin film transistor can be used as the write-side switch 183. The gate terminals (control terminals) of these thin film transistors are connected to the same signal line, and the ON and OFF states are controlled based on the signal level of the switching control signal AZ applied to the signal line.

<Display pixel>
Further, as shown in FIG. 1, the display pixels PX according to the present embodiment are arranged in the column direction (vertical direction in the drawing) and the selection line SL arranged in the row direction (horizontal direction in the drawing) of the display panel. An organic EL element OEL that is disposed near each intersection with the data line DL and is a current-controlled light emitting element, and a light emission driving current having a current value corresponding to display data is supplied to the organic EL element OEL. And a light emission driving circuit DC.

  In the light emission drive circuit DC, for example, a gate terminal (control terminal) is applied to the selection line SL, and a drain terminal and a source terminal (one end and the other end of the current path) are supplied with a supply voltage line VL and a contact. The thin film transistor (second switch means) Tr11 connected to N11, the gate terminal (control terminal) to the selection line SL, the source terminal and the drain terminal (one end and the other end of the current path) to the data line DL and the contact N12 The thin film transistor (third switch means) Tr12 and the gate terminal (control terminal) are connected to the contact N11, the drain terminal and the source terminal (one end and the other end of the current path) are connected to the supply voltage line VL and the contact (connection), respectively. Thin film transistor (light emitting drive element, first switch means) Tr13 connected to each of the contacts N12, the contact N11 and the contacts Between 12 (the thin film transistor Tr13 gate - between the source terminal) has a capacitor Cs connected, the configuration with. Here, the thin film transistor Tr13 corresponds to a light emission driving switching element whose threshold voltage is measured by the detection voltage ADC 140 and the threshold data latch unit 160 in the display driving device 100 described above.

  The organic EL element OEL has an anode terminal connected to the contact N12 of the light emission drive circuit DC, and a common voltage Vcom applied to the cathode terminal. Here, the common voltage Vcom is used in a write operation period in which a grayscale signal (grayscale current or non-light emitting display voltage) corresponding to display data is supplied to the light emission drive circuit DC in a display drive operation described later. The light emission driving current is supplied to the organic EL element (light emitting element) OEL which is equal to or higher than the supply voltage Vsc set to the low potential (Vs). In the light emission operation period in which the light emission operation is performed at a predetermined luminance gradation, the potential is set to an arbitrary potential (for example, ground potential GND) that is lower than the supply voltage Vsc set to the high potential (Ve). (Vs ≦ Vcom <Ve).

  Here, the capacitor Cs may be a parasitic capacitance formed between the gate and the source of the thin film transistor Tr13. In addition to the parasitic capacitance, a capacitor is further connected in parallel between the contact N11 and the contact N12. There may be. Further, the thin film transistors Tr11 to Tr13 are not particularly limited. However, by forming all the thin film transistors Tr11 to Tr13 by n channel thin film transistors, n channel amorphous silicon thin film transistors can be favorably applied. In this case, by applying an already established amorphous silicon manufacturing technique, a light emission driving circuit composed of an amorphous silicon thin film transistor having stable element characteristics (such as electron mobility) can be manufactured by a relatively simple manufacturing process. In the following description, a case where all the thin film transistors Tr11 to Tr13 are configured by n-channel thin film transistors will be described. Further, the light emitting element driven to emit light by the light emission driving circuit DC is not limited to the organic EL element OEL, and may be another light emitting element such as a light emitting diode as long as it is a current control type light emitting element. .

<Display Drive Device / Display Pixel Drive Control Method>
Next, a drive control method (drive control operation) in a case where gradation display is performed by causing the light emitting elements of the display pixels to perform a light emission operation in the display driving device having the above-described configuration will be described with reference to the drawings.

  The drive control operation in the display drive device 100 according to the present embodiment is roughly classified into the respective displays arranged on the display panel at an arbitrary timing prior to a display drive operation (precharge operation, write operation, light emission operation) described later. Threshold voltage detection operation (threshold voltage detection period) for measuring and storing a threshold voltage of a thin film transistor Tr13 (switching element; light emission drive element) for driving light emission provided in the pixel PX (light emission drive circuit DC) A first step), and after the threshold voltage detection operation ends, the light emission driving thin film transistor Tr13 provided in each display pixel PX holds a voltage component corresponding to the threshold voltage (the threshold voltage is set). In addition, a gradation signal (a gradation current having a predetermined current value) corresponding to the display data is written, and a desired luminance gradation corresponding to the gradation signal is written. Display drive operation for light emission operation of the machine EL element OEL (the display drive period), is configured to include a.

Hereinafter, each control operation will be described.
(Threshold voltage detection operation)
FIG. 2 is a timing chart showing the threshold voltage detection operation in the display driving apparatus according to the present embodiment. 3 is a conceptual diagram illustrating a voltage application operation in the display driving apparatus according to the present embodiment, and FIG. 4 is a conceptual diagram illustrating a voltage convergence operation in the display driving apparatus according to the present embodiment. These are the conceptual diagrams which show the voltage reading operation | movement in the display drive device which concerns on this embodiment. FIG. 6 is a diagram illustrating an example of drain-source current characteristics when the gate-source voltage is set to a predetermined condition and the drain-source voltage is modulated in an n-channel thin film transistor. .

  As shown in FIG. 2, the threshold voltage detection operation in the display drive device according to the present embodiment is performed by displaying pixels from the display drive device 100 via the data line DL within a predetermined threshold voltage detection period Tdec. A threshold voltage detection voltage (detection voltage Vpv) is applied to PX, and the detection voltage Vpv is applied between the gate and the source of the light emission driving thin film transistor Tr13 provided in the light emission driving circuit DC of the display pixel PX. A voltage application period (detection voltage application step) Tpv that holds the corresponding voltage component (that is, charges corresponding to the detection voltage Vpv are accumulated in the capacitor Cs), and the gate-source of the thin film transistor Tr13 in the voltage application period Tpv A part of the voltage component (charge accumulated in the capacitor Cs) held therebetween is discharged, and the drain-source current of the thin film transistor Tr13 is discharged. Only a voltage component (charge) corresponding to the threshold voltage of Ids is held between the gate and source of the thin film transistor Tr13 (remains in the capacitor Cs), and after the elapse of the voltage convergence period Tcv, the thin film transistor Tr13 The voltage component (voltage value based on the charge remaining in the capacitor Cs; threshold voltage Vth13) held between the gate and the source is measured, converted into digital data, and stored in a predetermined storage area of the frame memory 170 The voltage reading period (threshold voltage detection step) Trv to be stored is set to include (Tdec ≧ Tpv + Tcv + Trv).

  Here, the threshold voltage Vth13 of the drain-source current Ids of the thin film transistor Tr13 is an operating boundary where the drain-source current Ids of the thin film transistor Tr13 starts to flow when a slight voltage is further applied between the drain and source. The gate-source voltage Vgs of the thin film transistor Tr13. In particular, the threshold voltage Vth13 measured in the voltage reading period Trv according to the present embodiment varies with the driving history (light emission history), usage time, and the like with respect to the threshold voltage in the initial manufacturing state of the thin film transistor Tr13 ( The threshold voltage at the time of execution of the threshold voltage detection operation after occurrence of (Vth shift) is shown.

Hereinafter, each operation period related to the threshold voltage detection operation will be described in more detail.
(Voltage application period)
First, in the voltage application period Tpv, as shown in FIGS. 2 and 3, an on-level (high level) selection signal Ssel is applied to the selection line SL of the light emission drive circuit DC, and the supply voltage line VL is applied to the supply voltage line VL. A low-potential supply voltage Vsc (= Vs) is applied. Here, the low potential supply voltage Vsc (= Vs) may be a voltage equal to or lower than the common voltage Vcom, and may be, for example, the ground potential GND.

  On the other hand, in synchronization with this timing, the switching control signal AZ is set to a high level, the writing side switch 183 is set to the on state, the voltage detection side switch 181 is set to the off state, and the input selection switch 182 is set to the compensation voltage. By switching to the DAC 150 side, the threshold voltage detection voltage Vpv output from the compensation voltage DAC 150 is passed through the data line input / output switching unit 180 (input selection switch 182 and write side switch 183). , Applied to the data line DL.

  Thereby, the thin film transistors Tr11 and Tr12 provided in the light emission drive circuit DC constituting the display pixel PX are turned on, and the supply voltage Vsc is supplied to the gate terminal of the thin film transistor Tr13 and one end side of the capacitor Cs (contact N11) via the thin film transistor Tr11. The detection voltage Vpv applied to the data line DL is applied to the source terminal of the thin film transistor Tr13 and the other end side (contact N12) of the capacitor Cs via the thin film transistor Tr12.

  Here, in the display pixel PX (light emission drive circuit DC), with respect to the n-channel type thin film transistor Tr13 that supplies the light emission drive current to the organic EL element OEL, the drain-source voltage at the predetermined gate-source voltage Vgs. When the change characteristic of the drain-source current Ids when Vds is modulated is verified, it can be represented by a characteristic diagram as shown in FIG.

  In FIG. 6, the horizontal axis represents the partial pressure of the thin film transistor Tr13 and the partial pressure of the organic EL element OEL connected in series thereto, and the vertical axis represents the current value of the drain-source current Ids of the thin film transistor Tr13. A one-dot chain line in the figure is a boundary line of the threshold voltage between the gate and the source of the thin film transistor Tr13, the left side of the boundary line is an unsaturated region, and the right side is a saturated region. The solid line shows the gate-source voltage Vgs of the thin film transistor Tr13, the voltage Vgsmax at the time of light emission operation at the maximum luminance gradation, and the voltage Vgs1 at the time of light emission operation at any (different) luminance gradation below the maximum luminance gradation. The graph shows the change characteristics of the drain-source current Ids when the drain-source voltage Vds of the thin film transistor Tr13 is modulated when fixed to (<Vgsmax) and Vgs2 (<Vgs1). A broken line is a load characteristic line (EL load line) when the organic EL element OEL is caused to emit light, and a voltage on the right side of the EL load line is a voltage between the supply voltage Vsc and the common voltage Vcom (as an example, in the drawing). 20V), and the left side of the EL load line corresponds to the drain-source voltage Vds of the thin film transistor Tr13. The partial pressure of the organic EL element OEL gradually increases as the luminance gradation increases, that is, as the current value of the drain-source current Ids (light emission drive current≈gradation current) of the thin film transistor Tr13 increases.

  In FIG. 6, in the unsaturated region, even if the gate-source voltage Vgs of the thin film transistor Tr13 is set constant, the drain-source current Ids is increased as the drain-source voltage Vds of the thin film transistor Tr13 increases. The value is significantly increased (changes). On the other hand, in the saturation region, when the gate-source voltage Vgs of the thin film transistor Tr13 is set constant, even if the drain-source voltage Vds increases, the drain-source current Ids of the thin film transistor Tr13 does not increase so much and is substantially constant. It becomes.

  Here, in the voltage application period Tpv, the detection voltage Vpv applied from the compensation voltage DAC 150 to the data line DL (further, the source terminal of the thin film transistor Tr13 of the display pixel PX (light emission drive circuit DC)) has a low potential. In the characteristic diagram shown in FIG. 6 which is sufficiently lower than the set supply voltage Vsc (= Vs), the drain-source voltage Vds in the region where the gate-source voltage Vgs of the thin film transistor Tr13 exhibits saturation characteristics is obtained. Is set to such a voltage value. In the present embodiment, the detection voltage Vpv may be set to a maximum voltage that can be applied from the compensation voltage DAC 150 to the data line DL, for example.

Further, the detection voltage Vpv is set so as to satisfy the following expression (1).
| Vs-Vpv |> Vth12 + Vth13 (1)
In the above equation (1), Vth12 is a threshold voltage between the drain and source of the thin film transistor Tr12 when the on-level selection signal Ssel is applied to the gate terminal of the thin film transistor Tr12. In addition, since a low-potential supply voltage Vsc (= Vs) is applied to both the gate terminal and the drain terminal of the thin film transistor 13 and are substantially equal to each other, Vth13 is a voltage between the drain and source of the thin film transistor Tr13. It is a threshold voltage, and is also a threshold voltage between the gate and source of the thin film transistor Tr13. Although Vth12 + Vth13 gradually increases with time, the potential difference of (Vs−Vpv) is set large so as to always satisfy the equation (1).

  Thus, by applying a potential difference Vcp (both end potential Vc) larger than the threshold voltage Vth13 of the thin film transistor Tr13 between the gate and the source of the thin film transistor Tr13 (that is, both ends of the capacitor Cs), the voltage Vcp is applied. A corresponding large current Ipv for detection flows forcibly from the supply voltage line VL toward the compensation voltage DAC 150 via the drain-source of the thin film transistor Tr13. Therefore, electric charges corresponding to the potential difference based on the detection current Ipv are quickly accumulated at both ends of the capacitor Cs (that is, the voltage Vcp is charged in the capacitor Cs). In the voltage application period Tpv, not only charges are accumulated in the capacitor Cs, but also the detection current Ipv flows through other capacitance components in the current route from the supply voltage line VL to the data line DL, so Accumulation is performed.

  At this time, since the common voltage Vcom (= GND) higher than the low-potential supply voltage Vsc (= Vs) applied to the supply voltage line VL is applied to the cathode terminal of the organic EL element OEL, the organic EL element The anode-cathode is set between the anode and the cathode of the element OEL, and the light emission drive current does not flow through the organic EL element OEL, and the light emission operation is not performed.

(Voltage convergence period)
Next, in the voltage convergence period Tcv after the end of the voltage application period Tpv, as shown in FIGS. 2 and 4, an on-level selection signal Ssel is applied to the selection line SL, and a low potential is applied to the supply voltage line VL. When the supply voltage Vsc (= Vs) is applied, the switching control signal AZ is switched to the low level, so that the voltage detection side switch 181 is set to the on state and the write side switch 183 is Set to off state. Further, the output of the detection voltage Vpv from the compensation voltage DAC 150 is stopped. Accordingly, since the thin film transistors Tr11 and Tr12 are kept on, the display pixel PX (light emission drive circuit DC) is electrically connected to the data line DL, but the voltage application to the data line DL is performed. Therefore, the other end side (contact N12) of the capacitor Cs is set to a high impedance state.

  At this time, the gate voltage of the thin film transistor Tr13 is held by the electric charge (both-end potential Vc = Vcp> Vth13) accumulated in the capacitor Cs in the voltage application period Tpv described above, and the thin film transistor Tr13 is held in the ON state. Since the current continues to flow between the drain and source, the potential on the source terminal side (contact N12; the other end side of the capacitor Cs) of the thin film transistor Tr13 gradually increases so as to approach the potential on the drain terminal side (supply voltage line VL side). I will do it.

  As a result, a part of the electric charge accumulated in the capacitor Cs is discharged, the gate-source voltage Vgs of the thin film transistor Tr13 is lowered, and finally converges on the threshold voltage Vth13 of the thin film transistor Tr13. Change. Along with this, the drain-source current Ids of the thin film transistor Tr13 decreases, and the current flow finally stops.

  Even during this voltage convergence period Tcv, the potential of the anode terminal (contact N12) of the organic EL element OEL is equal to or less than the common voltage Vcom on the cathode terminal side. No voltage or reverse bias voltage is still applied to the organic EL element OEL, and the organic EL element OEL does not perform light emission.

(Voltage reading period)
Next, in the voltage reading period Trv after the lapse of the voltage convergence period Tcv, as shown in FIGS. 2 and 5, an on-level selection signal Ssel is applied to the selection line SL as in the voltage convergence period Tcv. , The detection voltage ADC 140 electrically connected to the data line DL and the threshold in the state where the low-potential supply voltage Vsc (= Vs) is applied to the supply voltage line VL and the switching control signal AZ is set to the low level. The value data latch unit 160 measures the potential (detection voltage Vdec) of the data line DL.

  Here, the data line DL after the lapse of the voltage convergence period Tcv is in a state of being connected to the source terminal (contact N12) side of the thin film transistor Tr13 through the thin film transistor Tr12 set in the ON state. Thus, the potential on the source terminal (contact N12) side of the thin film transistor Tr13 corresponds to the potential on the other end side of the capacitor Cs in which charges corresponding to the threshold voltage Vth13 of the thin film transistor Tr13 are accumulated.

  On the other hand, the potential on the gate terminal (contact N11) side of the thin film transistor Tr13 is a potential on one end side of the capacitor Cs in which electric charges corresponding to the threshold voltage Vth13 of the thin film transistor Tr13 are accumulated, and at this time, it is set to the on state. The thin film transistor Tr11 is connected to a low potential supply voltage Vsc.

  As a result, the potential of the data line DL measured by the detection voltage ADC 140 corresponds to the potential on the source terminal side of the thin film transistor Tr13 or the potential corresponding to the potential, so the detection voltage Vdec and the preset voltage Is determined based on the difference (potential difference) from the low-potential supply voltage Vsc (for example, the ground potential GND), that is, the gate-source voltage Vgs of the thin film transistor Tr13 (the potential Vc across the capacitor Cs), that is, the thin film transistor Tr13. Threshold voltage Vth13 or a voltage corresponding to the threshold voltage Vth13 can be detected.

  Then, the threshold voltage Vth13 (analog signal voltage) of the thin film transistor Tr13 detected in this way is converted into threshold detection data composed of a digital signal voltage by the detection voltage ADC 140, and the threshold data latch unit 160 is converted. The threshold detection data of each display pixel PX for one row is sequentially read out by the shift register / data register unit 110 and stored (stored) in a predetermined storage area of the frame memory 170. Here, the threshold voltage Vth13 of the thin film transistor Tr13 provided in the light emission drive circuit DC of each display pixel PX has a different degree of variation (Vth shift) depending on the drive history (light emission history) in each display pixel PX. The frame memory 170 stores threshold value detection data unique to each display pixel PX.

  Such a series of threshold voltage detection operations are executed at an arbitrary timing prior to a display driving operation described later, for example, when the system (display device) is started up or resumed from a hibernation state. As will be described in the drive control method of the apparatus, all the display pixels arranged in the display panel are executed within a predetermined threshold voltage detection period.

(Display drive operation: gradation display operation)
FIG. 7 is a timing chart showing a drive control method (gradation display operation) in the display drive apparatus according to the present embodiment. FIG. 8 is a conceptual diagram showing a precharge operation in the display driving device according to the present embodiment, and FIG. 9 is a conceptual diagram showing a data writing operation in the display driving device according to the present embodiment. 10 is a conceptual diagram showing a light emitting operation in the display driving apparatus according to the present embodiment.

  As shown in FIG. 7, the display driving operation in the display driving apparatus according to the present embodiment is performed by displaying pixels from the display driving apparatus 100 via the data line DL within a predetermined display driving period (one processing cycle period) Tcyc. By applying a predetermined precharge voltage Vpre to PX, the drain-source current Ids of the thin film transistor Tr13 is set between the gate and source of the light emission driving thin film transistor Tr13 provided in the light emission driving circuit DC of the display pixel PX. A precharge period (second step, compensation voltage application step) Tth in which a voltage component equivalent to the threshold voltage Vth13 is held (charge is accumulated or discharged in the capacitor Cs) and the threshold voltage is compensated is displayed. A gradation signal (gradation current) corresponding to the data is applied to the display pixel PX (light emission drive circuit DC) via the data line DL, and the thin film transistor is applied. Write operation for writing a gradation signal between the gate and source of the transistor Tr13 by adding a voltage component corresponding to the threshold voltage Vth13 held in the precharge period Tth to the voltage component corresponding to the gradation signal Based on the period (third step, data writing step) Twrt and the total voltage component (total charge amount accumulated in the capacitor Cs) held between the gate and the source of the thin film transistor Tr13, the display data corresponds to the display data. A light emission operation period (gradation light emission step) Tem in which a light emission drive current having a current value is caused to flow through the organic EL element OEL to perform light emission operation at a predetermined luminance gradation (Tcyc ≧ Tth + Twrt + Tem) is included. .

  Here, the one processing cycle period applied to the display driving period Tcyc according to the present embodiment is set to a period required for the display pixel PX to display image information for one pixel in one frame image, for example. Is done. That is, as described in the drive control method for the display device to be described later, when one frame image is displayed on a display panel in which a plurality of display pixels PX are arranged in a matrix in the row direction and the column direction, the one processing cycle period. Tcyc is set to a period required for the display pixels PX for one row to display one row of images in one frame image.

Hereinafter, each operation period related to the display driving operation will be described in more detail.
(Precharge period)
First, in the precharge period Tth, as in the voltage application period Tpv described above, an on-level (high-level) selection signal Ssel is applied to the selection line SL of the light emission drive circuit DC, as shown in FIGS. In addition, a low-potential supply voltage Vsc (= Vs; for example, ground potential GND) is applied to the supply voltage line VL.

  Thereby, the thin film transistors Tr11 and Tr12 provided in the light emission drive circuit DC are turned on, and the supply voltage Vsc is applied to the gate terminal (contact N11; one end side of the capacitor Cs) of the thin film transistor Tr13 through the thin film transistor Tr11. The source terminal (contact N12) of the thin film transistor Tr13 is electrically connected to the data line DL via the thin film transistor Tr12.

On the other hand, in synchronization with this timing, the switching control signal AZ is set to the high level, the writing side switch 183 is set to the on state, the voltage detection side switch 181 is set to the off state, and the input selection switch 182 is set to the compensation voltage. The setting is switched to the DAC 150 side.
As a result, the precharge voltage Vpre output from the compensation voltage DAC 150 is applied to the data line DL via the data line input / output switching unit 180 (the input selection switch 182 and the write side switch 183), and further the light emission. The precharge voltage Vpre is applied to the source terminal (contact N12) of the thin film transistor Tr13 through the thin film transistor Tr12 provided in the drive circuit DC.

  Here, in the precharge period Tth, the precharge voltage Vpre applied to the source terminal (contact N12) of the thin film transistor Tr13 of the display pixel PX (light emission drive circuit DC) from the compensation voltage DAC 150 via the data line DL is: In the threshold voltage detection operation described above, the threshold voltage detection that is detected for each display pixel PX by the detection voltage ADC 140 and the threshold data latch unit 160 and is individually stored in the frame memory 170 for each display pixel PX. Based on the data, the thin film transistor Tr13 has a voltage value that compensates for the threshold voltage Vth13 unique to the thin film transistor Tr13 of each display pixel PX (light emission drive circuit DC), and is applied by the precharge voltage Vpre. Threshold between the gate and source (both ends of capacitor Cs) It is set to a voltage value that can hold the voltage component corresponding pressure Vth 13.

  More specifically, the threshold voltage Vth13 of the thin film transistor Tr13 is described. As described above, n-channel amorphous silicon thin film transistors are applied as the thin film transistors Tr11 to Tr13 constituting the light emission drive circuit DC provided in the display pixel PX. In this case, the already established amorphous silicon manufacturing technique can be applied to form a thin film transistor with uniform element characteristics, and a light emission driving circuit with stable operating characteristics can be manufactured with a relatively simple manufacturing process. Has the advantage.

  However, it is known that, in an amorphous silicon thin film transistor, in general, a threshold voltage variation (Vth shift) due to a driving history occurs remarkably. As a drive control method for suppressing the influence of such threshold voltage fluctuations, as will be described later, the light emission drive circuit DC provided in the display pixel PX has a level corresponding to the display data via the data line DL. There is known a drive control method of a current gradation designation method (or current gradation designation drive) in which a current component (gradation current) of a modulation signal is directly flowed. In addition to the gate-source of the thin film transistor Tr13 (both ends of the capacitor Cs), the capacitance component (parasitic) formed in the path to which the gradation current is supplied is also charged to a predetermined voltage by the gradation current. Therefore, in particular, when a light emission operation (low gradation display) is performed at a low luminance gradation, the above-described charging operation takes time due to a small gradation current, and the gradation signal is not generated within a predetermined time. Write operation is completed In other words, insufficient writing occurs in which the voltage component held between the gate and source of the thin film transistor Tr13 (both ends of the capacitor Cs) is insufficient for the display data, and the light emission operation at a desired luminance gradation is not performed. there is a possibility.

  More specifically, in the current gray scale designation type drive control method, a thin film transistor required for flowing a gray scale current corresponding to display data between the drain and source of the thin film transistor Tr13 during a write operation to be described later. Many voltage components of the gate-source voltage Vgs of Tr13 contribute to the threshold voltage Vth13 of the thin film transistor Tr13. In particular, the organic EL element OEL emits light at the lowest luminance gradation (LSB). In the gate-source voltage Vgs (= Vlsb) of the thin film transistor Tr13 required for the generation, the ratio of the voltage component contributing to the threshold voltage Vth13 out of the held voltage component (total charge) is larger by 50%. As a result of various experiments by the inventors of the present application, it has been found that the value exceeds the limit.

  A voltage component (amount of charge) corresponding to the threshold voltage Vth13 is applied to a gradation signal (a gradation of a minute current value) without applying the precharge operation (application of the precharge voltage Vpre) according to the present embodiment. If an attempt is made to charge the gate-source (capacitor Cs) only by a current (write) write operation, a write operation period Twrt, which will be described later, becomes significantly longer. As a result, image information is stored in a predetermined processing period (frame). There is a possibility that a problem that the display is not performed well during (period) will occur.

  Therefore, in this embodiment, a precharge period Tth is provided and a precharge voltage Vpre is applied prior to a gradation signal writing operation to be described later, thereby applying a precharge voltage Vpre between the gate and the source of the thin film transistor Tr13 (both ends of the capacitor Cs). ), The current threshold voltage of the thin film transistor Tr13 (threshold voltage at the time of the threshold voltage detection operation after the Vth shift by the drive history) Vth13 is set to be held, Even with a small gradation current at the time of low gradation display, the display data is not charged by charging the voltage component corresponding to the threshold voltage Vth13 between the gate and source of the thin film transistor Tr13 (both ends of the capacitor Cs) by the gradation signal. Voltage component (substantial voltage component for gradation display according to display data, excluding the equivalent of threshold voltage Vth13; effective voltage Only the voltage Vdata) can be added to the voltage component corresponding to the threshold voltage Vth13 and held between the gate and source of the thin film transistor Tr13.

  During the precharge period Tth, the voltage component corresponding to the threshold voltage Vth13 inherent to the thin film transistor Tr13 is controlled between the gate and the source of the thin film transistor Tr13, so that the drain of the thin film transistor Tr13 is drained. -Almost no current flows between the sources, and the potential on the anode terminal (contact N12) side of the organic EL element OEL is equal to or less than the common voltage Vcom on the cathode terminal side. Therefore, no voltage or reverse bias voltage is applied to the organic EL element OEL, and the organic EL element OEL does not emit light.

  In this way, in order to hold a voltage component corresponding to the threshold voltage Vth13 between the gate and source of the thin film transistor Tr13, a current based on the voltage component is not supplied to the light emission drive circuit DC and the data line DL, and each thin film transistor Tr13 is supplied. Since the precharge voltage Vpre having a voltage value corresponding to the inherent threshold voltage Vth13 is directly applied to the source terminal (contact N12) side of the thin film transistor Tr13, each display pixel PX (light emission drive circuit DC). The light emission driving thin film transistor Tr13 (capacitor Cs) can be quickly charged with a voltage component corresponding to the threshold voltage Vth13.

(Write operation period)
Next, in the write operation period Twrt after the end of the precharge period Tth, as shown in FIGS. 7 and 9, an on-level selection signal Ssel is applied to the selection line SL, and a low potential is applied to the supply voltage line VL. The supply voltage Vsc (= Vs) is applied and the switching control signal AZ is set to the high level, and the input selection switch 182 is switched to the gradation signal generation unit 130 side to display the display data. Accordingly, the gradation signal (negative gradation current Idata) output from the gradation signal generation unit 130 is transferred to the data via the data line input / output switching unit 180 (the input selection switch 182 and the writing side switch 183). Supplied to line DL. Here, as the gradation signal, a negative gradation current Idata is supplied, and the current is drawn from the data line DL side toward the gradation signal generation unit 130 via the data line input / output switching unit 180. It flows like

  As a result, the thin film transistor Tr11 provided in the display pixel PX (light emission drive circuit DC) is turned on, and the low-potential supply voltage Vsc (= Vs) is connected to the gate of the thin film transistor Tr13 and one end side of the capacitor Cs via the thin film transistor Tr11. When the thin film transistor Tr12 is turned on and the gradation current Idata is drawn through the data line DL, a voltage lower than the supply voltage Vsc is applied to the source of the thin film transistor Tr13. Since it is applied to the terminal side (contact N12; the other end of the capacitor Cs), the thin film transistor Tr13 is turned on in a predetermined conduction state, and as shown in FIG. 9, from the supply voltage line VL, the thin film transistor Tr13, the contact N12, Thin film transistor Tr12, data line D Via the display drive apparatus 100 (the gradation signal generation unit 130), the write current Iwrt which corresponds to the current value of the gradation current Idata flows quickly.

  Here, in the capacitor Cs connected between the gate and the source of the thin film transistor Tr13, a voltage component corresponding to the threshold voltage Vth13 unique to the thin film transistor Tr13 is held (charge is accumulated) in the above-described precharge period Tth. Therefore, the charge of the capacitance required for the write current Iwrt based on the gradation current Idata to be stabilized between the drain and source of the thin film transistor Tr13 does not include the threshold voltage Vth13, and is displayed. A gray-scale current Idata (write current Iwrt) having a current value for charging only the effective voltage Vdata for gray-scale display according to data may be used, and between the gate and source of the thin film transistor Tr13 in a relatively short time. The electric charge can be charged to both ends of the capacitor Cs.

  Therefore, even when the threshold voltage Vth13 of the thin film transistor Tr13 is shifted by Vth due to the light emission history (driving history) or the like, the voltage component Vdata corresponding to the gradation signal (display data) is appropriately applied to the writing operation period Twrt. Can write quickly and well. In this write operation period Twrt, the gate-source voltage Vgs of the thin film transistor Tr13, that is, the amount of charge accumulated in the capacitor Cs, is uniquely determined by the drain-source current (write current Iwrt) of the thin film transistor Tr13. Therefore, the voltage Vc charged in the capacitor Cs is specifically the sum of the threshold voltage Vth13 inherent to the thin film transistor Tr13 and the voltage component (effective voltage) Vdata corresponding to the gradation current Idata (Vth13 + Vdata). It becomes.

  At this time, a low-potential supply voltage Vsc (= Vs) is applied to the supply voltage line VL, and the write current Iwrt is supplied from the supply voltage line VL to the data line DL through the light emission drive circuit DC. Since it is controlled to flow, the potential applied to the anode terminal (contact N12) of the organic EL element OEL is equal to or lower than the potential Vcom (GND) of the cathode terminal, so that a reverse bias voltage is applied to the organic EL element OEL. As a result, no light emission drive current flows through the organic EL element OEL, and no light emission operation is performed.

(Light emission operation period)
Next, in the light emission operation period Tem after the end of the write operation period Twrt, as shown in FIGS. 7 and 10, an off level (low level) selection signal Ssel is applied to the selection line SL, and the supply voltage line VL is applied. A high potential supply voltage Vsc (= Ve) is applied. In synchronism with this timing, the gradation signal generator 130 stops the gradation current Idata drawing operation.

  Thereby, the thin film transistors Tr11 and Tr12 provided in the light emission drive circuit DC are turned off, and the supply voltage Vsc to the gate terminal (contact N11; one end side of the capacitor Cs) and the drain terminal of the thin film transistor Tr13 is cut off. At the same time, since the electrical connection between the data line DL and the source terminal of the thin film transistor Tr13 (contact N12; the other end of the capacitor Cs) is cut off, the charge accumulated in the capacitor Cs during the write operation period Twrt described above. Retained.

  Note that, during the light emission operation period Tem, the high-potential supply voltage Vsc (= Ve) applied to the supply voltage line VL is an anode necessary for causing the organic EL element OEL to perform light emission operation at the maximum luminance gradation (MSB). The voltage value is set to be equal to or higher than the voltage (a positive voltage that is forward biased with respect to the voltage Vcom connected to the cathode side of the organic EL element OEL).

Specifically, the high-potential supply voltage Vsc (= Ve) is set to a voltage value that satisfies the following expression (2).
| Ve-Vcom |> Vdsmax + Velmax (2)
In the above equation (2), Vdsmax is the light emitting operation period Tem between the drain and source of the thin film transistor Tr13 in the saturation region shown in FIG. The maximum voltage value between the drain and source of the thin film transistor Tr13 is reached. Velmax is a partial pressure of the organic EL element OEL at the maximum luminance gradation.

  As described above, the sum (Vth13 + Vdata) of the voltage components charged in the capacitor Cs during the precharge operation and the write operation is held as the potential Vc across the capacitor Cs, whereby the gate-source voltage Vgs ( That is, the potential of the contact N11) is held, and the thin film transistor Tr13 maintains the on state.

  Therefore, during the light emission operation period Tem, as shown in FIG. 10, the light emission drive current Iem flows from the supply voltage line VL to the organic EL element OEL through the thin film transistor Tr13 and the contact N12, and the organic EL element OEL is driven to emit light. Light is emitted at a predetermined luminance gradation corresponding to the current value of the current Iem. Here, the charge (both-end potential Vc) held in the capacitor Cs during the light emission operation period Temp corresponds to the potential difference when the write current Iwrt corresponding to the gradation current Idata is passed through the thin film transistor Tr13 as described above. The light emission drive current Iem flowing through the organic EL element OEL has a current value (Iem≈Iwrt = Idata) equivalent to the write current Iwrt (gradation current Idata). As a result, the light emission drive current Iem corresponding to the predetermined light emission state (luminance gradation) is supplied based on the voltage component (effective voltage Vdata) written in the write operation period Twrt, and the organic EL element The OEL continuously emits light at a luminance gradation corresponding to display data (gradation signal).

  As described above, according to the display driving device and the display pixel according to the present embodiment, the voltage component corresponding to the threshold voltage Vth13 is held between the gate and the source of the thin film transistor Tr13 during the precharge period, and further, during the write operation period. A gradation current Idata (writing current Iwrt) designating a current value corresponding to the light emission state (luminance gradation) of the organic EL element OEL is forcibly passed between the drain and source of the thin film transistor Tr13, and the gate of the thin film transistor Tr13 By holding the voltage component Vdata corresponding to the current value between the sources, light emission that flows to the organic EL element (light emitting element) OEL substantially based on the voltage component (effective voltage Vdata) corresponding to the gradation current Idata. By controlling the drive current Iem, a current gradation designation type drive control method for emitting light at a predetermined luminance gradation is applied, and a single emission A function (current / voltage conversion function) for converting the current level of the gradation current Idata corresponding to desired display data (luminance gradation) to a voltage level by the switching element (thin film transistor Tr13) for driving light, and an organic EL element Since both the function of supplying the light emission drive current Iem having a predetermined current value to the OEL (light emission drive function) is realized, the variation in the element characteristics between the thin film transistors constituting the light emission drive circuit DC and the influence of the change over time are affected. Without receiving, desired light emission characteristics can be realized stably over a long period of time.

  In addition, according to the display driving device and the display pixel according to the present embodiment, the precharge operation is performed prior to the writing operation of the display data (gradation signal) to the display pixel PX and the light emitting operation of the organic EL element OEL. , The precharge voltage Vpre is applied to the capacitor Cs connected between the gate and the source terminal of the light emission driving thin film transistor Tr13 provided in each light emission drive circuit DC, so that the inherent characteristic of the thin film transistor Tr13 is obtained. The voltage component corresponding to the threshold voltage Vth13 can be maintained (charge is accumulated).

  Therefore, the threshold voltage Vth13 of the light emission driving switching element (thin film transistor Tr13) provided in each display pixel PX (light emission drive circuit DC) has changed (Vth shift) due to changes over time, drive history, or the like. Even in this case, in the above-described precharge operation, it is possible to set a state in which charges corresponding to the threshold voltage Vth13 unique to each thin film transistor Tr13 are appropriately accumulated. Thereby, in the display data writing operation, it is not necessary to charge the capacitor Cs to the threshold voltage Vth13 by the gradation current Idata based on the display data, and the voltage component (brightness gradation) corresponding to the display data (luminance gradation). Effective voltage) Since only Vdata needs to be charged, the charge based on the display data can be quickly accumulated in the capacitor Cs, and the occurrence of insufficient writing can be suppressed, and the appropriate luminance corresponding to the display data can be obtained. The organic EL element OEL can be caused to emit light with gradation.

  In the present embodiment, in the threshold voltage detection operation that is performed prior to the display drive operation, the voltage is applied to the light emission drive circuit DC (on the source terminal side of the thin film transistor Tr13) of each display pixel PX during the voltage application period Tpv. Although the configuration and drive control method of the display drive device in which the detection voltage Vpv is applied to the data line DL from the compensation voltage DAC 150 via the input selection switch 182 and the write side switch 183 have been shown, the present invention is not limited to this. For example, as shown below, a dedicated power source for applying the detection voltage Vpv to the data line DL may be provided.

FIG. 11 is a main part configuration diagram showing another configuration example of the display driving apparatus according to the present embodiment. Here, the description of the same configuration as the above-described embodiment is omitted.
As shown in FIG. 11, the display driving device according to the present configuration example includes a detection voltage Vpv that is output separately from the compensation voltage DAC 150 in addition to the configuration of the display driving device 100 described above (see FIG. 1). The input selection switch 182 provided in the data line input / output switching unit 180 includes a compensation voltage DAC 150 (precharge voltage Vpre) and a gradation signal generation unit 130 (gradation current Idata). In addition, any one of the three components including the detection voltage power supply 190 (detection voltage Vpre) can be selectively connected to the data line DL.

  According to this, in the voltage application period Tpv described above, an arbitrary voltage value is obtained only by controlling the input selection switch 182 and the write side switch 183 of the data line input / output switching unit 180 to the detection voltage power supply 190 side. Since the detection voltage Vpv can be applied to the data line DL, the processing load for the output operation of the detection voltage Vpv in the compensation voltage DAC 150 can be reduced.

(Display drive operation: Non-light emitting display operation)
Next, a driving control method in the case of performing non-light emitting display (black display) in which the light emitting element does not perform light emission in the display driving device and the display pixel having the above-described configuration will be described with reference to the drawings.

  FIG. 12 is a timing chart showing a drive control method (non-light emitting display operation) in the display driving apparatus according to the present embodiment. FIG. 13 is a conceptual diagram illustrating another example of the data writing operation in the display driving device according to the present embodiment. FIG. 14 is a conceptual diagram illustrating the non-light emitting operation in the display driving device according to the present embodiment. It is. Here, the description of the drive control equivalent to the gradation display operation described above is simplified or omitted.

  As shown in FIG. 12, the drive control operation in the display drive device according to the present embodiment is the light emission provided in each display pixel PX after the threshold voltage detection operation (threshold voltage detection period Tdec) described above. After the driving thin film transistor Tr13 holds a voltage component corresponding to the threshold voltage Vth13 and compensates for the threshold voltage Vth13, a gradation signal (non-light emitting display voltage Vzero) corresponding to the display data is written, and organic The display element includes a display driving operation (display driving period) for setting the EL element OEL to a non-light emitting state.

  In other words, in the drive control operation when performing the above-described gradation display operation, when shifting from the write operation period Twrt set during the display drive operation (display drive period Tcyc) to the light emission operation period Temp. The supply voltage Vsc is set so as to shift from the low potential (Vs) to the high potential (Ve). For this reason, a phenomenon occurs in which the potential (gate potential) applied to the gate terminal (contact N11) of the thin film transistor Tr13 rises due to the displacement of the charge held in the capacitive component parasitic on the thin film transistor Tr11.

  Here, when the luminance gradation based on the display data is the lowest gradation (black display state), the current value of the gradation current Idata is in a minute state or 0 (that is, the state in which the gradation current Idata does not flow). Since the voltage (both end potential Vc) charged in the capacitor Cs in the precharge period Tth is in the vicinity of the threshold voltage Vth13 unique to the thin film transistor Tr13, the write operation period Twrt to the light emission operation period Temp. Even if the gate potential fluctuates slightly due to the transition, the thin film transistor Tr13 is turned on and the light emission drive current Iem flows, and the non-light emission display (black display) operation corresponding to the display data is realized. There is a possibility that it will not be done (is unstable).

  In order to stabilize such a non-light emitting display operation, the voltage component (accumulated charge) charged in the capacitor Cs is discharged during the light emission operation period Tem, and the gate-source voltage Vgs (thin film transistor Tr13). The both-end potential Vc) of the capacitor Cs is set to be sufficiently lower than the threshold voltage Vth13 of the thin film transistor Tr13, more preferably 0V (that is, the contact N11 and the contact N12 are equipotential). It is desirable.

  In order to realize such a voltage state, when the writing operation is performed using the gradation current Idata having the minute current value as described above, the charge accumulated in the capacitor Cs is discharged to cause a gate-source connection. A relatively long time is required to set the voltage Vgs to a desired charge amount (voltage value). In particular, in the writing operation period Twrt of the previous display driving period (one processing cycle period) Tcyc, the closer the voltage component (both end potential Vc) charged to the capacitor Cs is to the maximum luminance gradation voltage, Since the amount of stored charge is large, it takes a longer time to discharge the charge to a desired voltage value.

  Therefore, in the display driving apparatus according to the present embodiment, as shown in FIG. 1, the gradation signal generation unit 130 emits the organic EL element (light emitting element) OEL with a predetermined luminance gradation according to the display data. In addition to the means for generating and supplying the gradation current Idata for generating, the non-emission display voltage Vzero for generating the darkest display (black display) operation without causing the organic EL element OEL to perform the light emission operation is generated and supplied. And a non-light emitting display voltage Vzero is applied to the data line DL at the lowest luminance gradation (black display state).

  In the present embodiment, the case where the gradation signal generation unit 130 applies the non-emission display voltage Vzero to the light emission drive circuit DC (source terminal side of the thin film transistor Tr13; contact N12) via the data line DL is shown. The present invention is not limited to this, and for example, a dedicated power supply for applying the non-light emitting display voltage Vzero to the data line DL may be provided.

  Then, the drive control method in the display drive device having such a configuration is as shown in FIG. 12, in the display drive operation after the above-described threshold voltage detection operation, as shown in FIG. During a period Tcyc, a predetermined precharge voltage Vpre is applied to the display pixel PX, and the thin film transistor is connected between the gate and the source of the light emitting driving thin film transistor Tr13 (both ends of the capacitor Cs) provided in the light emitting driving circuit DC. A precharge period Tth in which a voltage component corresponding to the threshold voltage Vth13 specific to Tr13 is held (charge is accumulated or discharged in the capacitor Cs), and a gradation signal (no light emission display data) corresponding to display data (non-light emitting display data) The light emission display voltage Vzero) is applied to each display pixel PX (light emission drive circuit DC) via the data line DL, and the thin film transistor Tr 13 discharges almost all of the electric charge held between the gate and the source (capacitor Cs), and sets the gate-source voltage Vgs of the thin film transistor Tr13 to 0 V, and the organic EL element OEL emits light. It is set so as to include a light emission operation period Temp that does not operate (no light emission operation) (Tcyc ≧ Tth + Twrt + Tem).

  That is, in the precharge operation prior to the writing operation period Twrt, the gate-source (capacitor Cs) of the thin film transistor Tr13 for driving light emission is connected in the same manner as the drive control operation when executing the gradation display operation described above. After the voltage component corresponding to the threshold voltage Vth13 inherent to the thin film transistor Tr13 is held (charge amount is accumulated), in the gradation signal writing operation, as shown in FIG. The generation unit 130) supplies, for example, a low potential supply voltage Vsc (= Vs) and a non-light emitting display voltage Vzero that is equipotential to the display pixel PX (light emission driving circuit) via the data line input / output switching unit 180 and the data line DL. DC) is directly applied to the source terminal side (contact N12) of the thin film transistor Tr13 provided to the gate-source voltage Vgs (capacitor). s both ends potential Vc) of the set to 0V.

  In this way, almost all of the electric charge accumulated in the capacitor Cs is discharged, and the gate-source voltage Vgs of the thin film transistor Tr13 becomes a voltage value (substantially 0 V) sufficiently lower than the threshold voltage Vth13 inherent to the thin film transistor Tr13. Therefore, when the write operation period Twr is shifted to the light emission operation period Temp, the supply voltage Vsc is displaced from the low potential (Vs) to the high potential (Ve), and the gate potential of the thin film transistor Tr13 (the potential of the contact N11). 14), the thin film transistor Tr13 does not perform the on operation (holds the off state), and the light emission drive current Iem is not supplied to the organic EL element OEL, as shown in FIG. Not performed (becomes a non-light emitting state).

  As a result, during the non-light emitting display operation, the gradation current corresponding to the non-light emitting display data is supplied via the data line DL, and almost the electric charge accumulated in the capacitor Cs connected between the gate and the source of the thin film transistor Tr13. Compared to the case where all are discharged, it is possible to satisfactorily realize the non-light-emitting state (non-light-emitting display operation) of the organic EL element OEL while shortening the time required for writing the non-light-emitting display data. Therefore, in addition to the display driving operation for performing the normal gradation display described above, the display driving operation for performing the non-light emitting display is switched and controlled in accordance with the display data (luminance gradation data), so that the desired display operation can be performed. The light emission operation with the number of gradations (for example, 256 gradations) can be realized with relatively high brightness and clarity.

  In the display pixel PX according to the present embodiment, as shown in FIG. 1, an n-channel amorphous silicon thin film transistor is applied as the thin film transistors Tr11 to Tr13 provided in the light emission drive circuit DC. However, a polysilicon thin film transistor may be applied, or a p-channel amorphous silicon thin film transistor may be applied. Here, when the p-channel type is applied to all, the signal on level and off level high and low are set to be inverted.

  Further, in the present embodiment, as shown in FIG. 1, a circuit configuration including three thin film transistors Tr11 to Tr13 is described as the light emission drive circuit DC provided in each display pixel PX. Is not limited to this. That is, a light emission driving circuit corresponding to the current gradation designation method, using a single thin film transistor, converting a gradation current supplied according to display data into a voltage component and connecting between the gate and the source To realize a current / voltage conversion function that accumulates in a capacitor or parasitic capacitance, and a light emission drive function that controls a light emission drive current supplied to a light emitting element (organic EL element) based on the accumulated voltage component. Needless to say, other circuit configurations may be used.

  Further, in the above-described display drive device and display pixel drive control method, as a precharge operation, each display pixel PX has a voltage value based on the threshold compensation data from the compensation voltage DAC 150 via the data line DL. Although the case where the charge voltage Vpre is applied has been described, the present invention is not limited to this. In short, the light emission driving thin film transistor Tr13 provided in the light emission drive circuit DC of each display pixel PX by the precharge operation. A voltage component that compensates the threshold voltage of the drain-source current Ids of each thin film transistor Tr13 (a voltage component corresponding to the threshold voltage Vth13 unique to the thin film transistor Tr13) can be held between the gate and the source. For example, the above threshold is applied from the display driving device 100. The precharge current having a current value based on the value compensation data, may have a structure to be applied through the data line DL in each display pixel PX.

<Display device>
Next, a display device and a drive control method thereof according to the present invention will be described with reference to the drawings.
FIG. 15 is a schematic block diagram showing an example of the overall configuration of the display device according to the present invention, and FIG. 16 shows a display panel and its peripheral circuits (selection driver, power driver) applied to the display device according to the present embodiment. It is a schematic block diagram which shows an example. Here, components equivalent to those of the display drive device and the display pixel (light emission drive circuit) shown in the above-described embodiment will be described with reference to the above-described drawings with the same or equivalent reference numerals.

  As shown in FIGS. 15 and 16, the display device 200 according to the present embodiment roughly includes a plurality of selection lines (selection lines) SL arranged in the row direction and a plurality of data lines arranged in the column direction. A plurality of display pixels PX having a light emission driving circuit DC and an organic EL element (light emitting element) OEL having a circuit configuration equivalent to the above-described embodiment are arranged in the vicinity of each intersection with the (data line) DL in n rows × m columns. (N and m are arbitrary positive integers) arranged in a matrix and connected to a selection line SL of the display panel 210, and a selection signal sequentially at a predetermined timing for each selection line SL A selection driver (selection drive unit) 220 for applying Ssel and a supply voltage line VL arranged in the row direction in parallel with each of the selection lines SL are connected to each supply voltage line VL in order for a predetermined timing. Are connected to a power source driver (power source driving unit) 230 for applying a supply voltage Vsc of a predetermined voltage level and the data line DL of the display panel 210, and each data line DL is connected during the threshold voltage detection period Tdec described above. In addition, the threshold voltage at the time of the light emission driving switching element (thin film transistor) provided in the display pixel PX (light emission drive circuit DC) of each column is detected, and each data line DL is set in the display drive period Tcyc. After applying a precharge voltage Vpre corresponding to a threshold voltage specific to the switching element of the display pixel PX to the display pixel PX of each column, a grayscale signal (grayscale current Idata corresponding to each display data is applied. Or a data driver (data driving unit) 240 for supplying a non-light emitting display voltage Vzero) and a timing supplied from a display signal generation circuit 260 described later. A system controller 250 that generates and outputs at least a selection control signal, a power supply control signal, and a data control signal for controlling the operating states of the selection driver 220, the power supply driver 230, and the data driver 240 based on the switching signal; Based on a video signal supplied from the outside of the apparatus 200, display data (luminance gradation data) composed of a digital signal is generated and supplied to the data driver 240, and a predetermined value is applied to the display panel 210 based on the display data. A display signal generation circuit 260 that extracts or generates a timing signal (system clock or the like) for displaying image information and supplies the timing signal to the system controller 250 is provided.

Hereafter, each said structure is demonstrated concretely.
(Display panel)
Each display pixel PX arranged in the display panel 210 shown in FIG. 16 is a selection applied from the selection driver 220 via the selection line SL, similarly to the display pixel shown in the above-described embodiment (see FIG. 1). The signal Ssel, the supply voltage Vsc applied from the power supply driver 230 via the supply voltage line VL, and the gradation signal (gradation current Idata or non-light-emitting display) supplied from the data driver 240 via the data line DL A light emission drive circuit DC that generates a light emission drive current Iem according to display data based on the voltage Vzero) and a predetermined luminance gradation according to the current value of the light emission drive current Iem supplied from the light emission drive circuit DC. And an organic EL element (light emitting element) OEL that emits light. Note that, in the present embodiment, as in the above-described embodiment (see FIG. 1), the case where the organic EL element OEL is applied as the light emitting element is shown, but a predetermined luminance gradation according to the current value of the light emission driving current. Other light-emitting elements may be used as long as they are current-controlled light-emitting elements that perform a light-emitting operation.

(Selected driver)
The selection driver 220 applies an on-level (high level in the above-described display pixel) selection signal Ssel to each selection line SL based on a selection control signal supplied from the system controller 250, thereby The display pixel PX is set to the selected state. Specifically, for the display pixels PX in each row, the selection signal Ssel is applied to the row during the period of performing the threshold voltage detection operation and the display drive operation (precharge operation and writing operation) excluding the light emission operation. By sequentially executing the operation to be applied to the selection line SL for each row at a predetermined timing, the display pixels PX for each row are sequentially set to the selected state.

  Here, for example, as shown in FIG. 16, the selection driver 220 corresponds to the selection line SL of each row based on a selection clock signal SCK and a selection start signal SST supplied as a selection control signal from a system controller 250 described later. A known shift register 221 that sequentially outputs shift signals to be output, and an output supplied as a selection control signal from the system controller 250 by converting the shift signal output from the shift register 221 to a predetermined signal level (on level) An output circuit unit (output buffer) 222 that outputs a selection signal Ssel to each selection line SL based on the control signal SOE is provided.

(Power supply driver)
Based on the power supply control signal supplied from the system controller 250, the power supply driver 230 applies the high potential supply voltage Vsc (= Ve) to the supply voltage line VL of the row for the display pixels PX of each row only during the light emission operation period. The low-potential supply voltage Vsc (= Vs) is applied during the operation period other than the light emission operation period (the threshold voltage detection period Tdec and the precharge period Tth and the write operation period Twrt in the display drive period Tcyc). Apply.

  Here, for example, as shown in FIG. 16, the power supply driver 230 is based on the clock signal VCK and the start signal VST supplied as the power supply control signal from the system controller 250, as in the selection driver 220 described above. A known shift register 231 that sequentially outputs a shift signal corresponding to the supply voltage line VL, and an output control signal VOE that is converted into a predetermined voltage level (voltage values Ve and Vs) and is supplied as a power control signal. And an output circuit section 232 for outputting the supply voltage Vsc to each supply voltage line VL.

(Data driver)
The data driver 240 is at least the shift register / data register unit 110, the display data latch unit 120, the gradation signal generation unit 130, and the like shown in FIG. , A detection voltage ADC 140, a compensation voltage DAC 150, a threshold data latch unit 160, a frame memory 170, and a data line input / output switching unit 180.

  In FIG. 1, a configuration corresponding to a single display pixel PX is shown. However, in the data driver 240 according to the present embodiment, for each data line DL arranged in the column direction of the display panel 210, The data line input / output switching unit 180 is provided, and the voltage detection side switch 181, the input selection switch 182 and the write side switch 183 constituting the data line input / output switching unit 180 are switched based on the drive control method described above. By doing so, the detection voltage Vpv, the precharge voltage Vpre, the gradation signal (the gradation current Idata, the non-light emitting display voltage Vzero) are simultaneously or concurrently applied to the display pixels PX in each row. ) Or an operation of measuring the detection voltage Vdec is selectively executed.

That is, the shift register / data register unit 110 provided in the data driver (display driving device) 240 according to the present embodiment is based on the data control signal (shift clock signal, sampling start signal) supplied from the system controller 250. The display for one row supplied from the display signal generation circuit 260 based on the output timing of the shift signal generated corresponding to the display pixel PX (or the data line DL for each column) for one row. Capture data sequentially.
Based on the data control signal (data latch signal), the display data latch unit 120 transfers the display data for one row taken in by the shift register / data register unit 110, and displays the data for each display pixel PX in each column. Retained.

  The gradation signal generation unit 130 is based on each display data held in the display data latch unit 120, and the gradation current Idata having a current value corresponding to the display data or the non-light emission having a predetermined voltage value. A display voltage Vzero is generated and applied to each data line DL simultaneously (in a lump) or sequentially as a gradation signal.

  Specifically, in the case where the display data is gray scale display data for performing normal gray scale display accompanied by the light emission operation of the organic EL element (light emitting element) OEL, for example, a predetermined value based on the gray scale reference voltage is used. Is converted into an analog signal voltage having a voltage value (digital-analog conversion processing), and further, a gradation current Idata having a current value corresponding to the display data is generated (voltage-current conversion processing), and a predetermined timing is obtained. When the display data is non-light-emitting display data not accompanied by the light-emitting operation of the organic EL element (light-emitting element) OEL, a predetermined non-light-emitting display voltage Vzero is set to a predetermined value. Output to the data line DL of the column at the timing.

  The non-light emission display voltage Vzero is a light emission driving switching provided in the light emission drive circuit DC constituting the display pixel PX by the precharge operation as shown in the drive control method (non-light emission display operation) described above. Electric charges accumulated between the gate and source (capacitor Cs) of the element (thin film transistor Tr13) are discharged, and the gate-source voltage Vgs (potential Vc across the capacitor Cs) is set to 0V (or approximated to 0V). ) Is set to any voltage value necessary for. Here, the non-light emitting display voltage Vzero and the gradation reference voltage for generating the gradation current Idata are supplied from, for example, power supply means (not shown).

  The detection voltage ADC 140 is a display pixel PX (light emission drive) in each column of the row set to the selected state in the threshold voltage detection operation prior to the display operation of the image information on the display panel 210 (display drive operation of the display pixel PX). The threshold voltage (or voltage component corresponding to the threshold voltage) at the time of execution of the threshold voltage detection operation of the switching element (thin film transistor Tr13) for driving light emission provided in the circuit DC) is The detection voltage Vdec is measured in parallel or sequentially through each data line DL, converted into threshold detection data composed of a digital signal voltage, and output to the threshold data latch unit 160.

  The compensation voltage DAC 150 is used for the display pixel PX (light emission drive) in each column of the row set to the selected state in the threshold voltage detection operation prior to the display operation of the image information on the display panel 210 (display drive operation of the display pixel PX). A predetermined detection voltage Vpv is simultaneously output in parallel or sequentially to each of the light emission driving switching elements provided in the circuit DC via the data lines DL.

  Further, the compensation voltage DAC 150 is specific to the switching element provided in the display pixel PX in each column of the row set in the selected state in the display operation of the image information on the display panel 210 (display drive operation of the display pixel PX). A precharge voltage Vpre is generated based on threshold compensation data for compensating the threshold voltage of the pixel, and is output to the display pixels PX in each column in parallel or sequentially via each data line DL. .

  The threshold data latch unit 160 is a display pixel in each column of the row set to the selected state in the threshold voltage detection operation prior to the display operation of the image information on the display panel 210 (display drive operation of the display pixel PX). For each PX, after the threshold detection data converted and generated by the detection voltage ADC 140 is captured and held, the threshold detection data for one row is extracted by the shift register / data register unit 110, and the frame The data is sequentially transferred to the memory 170.

  Further, the threshold data latch unit 160 is a selection state sequentially taken out from the frame memory 170 by the shift register / data register unit 110 in the display operation of the image information on the display panel 210 (display drive operation of the display pixel PX). The threshold compensation data corresponding to the threshold detection data for each display pixel PX in each column of the set row is captured and held, and transferred to the compensation voltage DAC 150 for each column.

(System controller)
The system controller 250 generates and outputs a selection control signal, a power supply control signal, and a data control signal for controlling the operation state to each of the selection driver 220, the power supply driver 230, and the data driver 240, thereby outputting each driver. By operating at a predetermined timing, a selection signal Ssel having a predetermined voltage level, a supply voltage Vsc, and a gradation signal (gradation current Idata, non-light emitting display voltage Vzero) are generated and output, and each display pixel PX ( Video signal by causing threshold voltage detection operation (voltage application operation, voltage convergence operation, voltage reading operation) and display drive operation (precharge operation, writing operation, light emission operation) in the light emission drive circuit DC) Control for displaying predetermined image information on the display panel 210 is performed.

(Display signal generation circuit)
For example, the display signal generation circuit 260 extracts a luminance gradation signal component from a video signal supplied from the outside of the display device 200, and converts the luminance gradation signal component from a digital signal for each row of the display panel 210. Is supplied to the shift register / data register unit of the data driver 240 as display data (luminance gradation data). Here, when the video signal includes a timing signal component that defines the display timing of the image information, such as a television broadcast signal (composite video signal), the display signal generation circuit 260 displays the luminance gradation signal component. In addition to the function of extracting the timing signal component, the timing signal component may be extracted and supplied to the system controller 250. In this case, the system controller 250 generates control signals to be individually supplied to the selection driver 220, the power supply driver 230, and the data driver 240 based on the timing signal supplied from the display signal generation circuit 260. .

  Note that the display device according to the present embodiment has a configuration in which the selection driver 220 connected to the selection line SL and the power supply driver 230 connected to the supply voltage line VL are individually provided around the display panel 210. As shown in the drive control method (see FIGS. 7 and 12) of the display drive device (corresponding to the data driver 240) described above, the display pixels PX in a specific row (from the selection driver 220) Since the selection signal Ssel applied to the selection line SL and the supply voltage Vsc applied to the supply voltage line VL (from the power supply driver 230) are set so that the signal levels are in an inverted relationship with each other, the display panel When the display drive operation (particularly, the light emission operation) is performed for each display pixel PX arranged in 210 independently in a row unit (specifically, a display device described later). In the case of the first example of the driving control method 200, the signal level of the selection signal Ssel generated by the selection driver 220 is inverted (level inversion processing), and further, the level conversion is performed so as to have a predetermined voltage level. Thus (level conversion processing), the configuration in which the power supply driver 230 is eliminated can be applied by applying the voltage to the supply voltage line VL of the row.

<Display device drive control method>
Next, a drive control method (drive control operation) in the display device according to the present embodiment will be described.
FIG. 17 is a timing chart schematically showing a first example of the drive control method for the display device according to the present embodiment. Here, the description of the drive control method (see FIGS. 2 and 7) equivalent to that in the display drive device and the display pixel (light emission drive circuit) shown in the above-described embodiment will be simplified. In the present embodiment, for convenience of explanation, it is assumed that the display panel has a configuration in which display pixels of 12 rows (1st to 12th rows) are arranged for convenience.

  A first example of the drive control operation of the display device 200 according to the present embodiment is as follows. First, as shown in FIG. 17, a display drive operation (display drive period) for displaying image information on the display panel 210 is performed. Prior to all the display pixels PX arranged in the display panel 210, a light emission driving switching element for controlling the light emission state of the organic EL element (light emitting element) OEL in the light emission drive circuit DC provided in each display pixel PX. A threshold voltage detection operation (threshold voltage detection period Tdec) for detecting a threshold voltage of the (thin film transistor) (or a voltage component corresponding to the threshold voltage) is executed, and then one frame period Tfr Within (approximately 16.7 msec), a voltage component corresponding to the threshold voltage of the switching element is maintained in the display pixel PX (light emission drive circuit DC) for each row of the display panel 210. Then, the gradation signal (gradation current Idata, non-light emitting display voltage Vzero) corresponding to the display data is written, and the display pixels PX (organic EL elements OEL) in each row are displayed as described above. A display drive operation (display drive period Tcyc) in which light emission operation is performed at a luminance gradation corresponding to data (gradation signal) is sequentially repeated for all rows, and image information for one screen of the display panel 210 is displayed.

  Here, the threshold voltage detection operation (threshold voltage detection period Tdec) is a predetermined value for the display pixel PX (light emission drive circuit DC) for each row of the display panel 210, as in the above-described embodiment. Voltage application operation for applying the detection voltage Vpv (voltage application period Tpv), and voltage convergence for converging the voltage component based on the detection voltage Vpv to the threshold voltage at the detection time of each switching element (thin film transistor Tr13). Operation (voltage convergence period Tcv) and threshold voltage Vth13 after voltage convergence in each display pixel PX is measured (read) and stored as threshold detection data for each display pixel PX (voltage reading) A series of drive control consisting of (period) is sequentially executed at a predetermined timing for each row.

  Here, in the timing chart shown in FIG. 17, hatched portions indicated by hatching in each row of the threshold voltage detection period Tdec are the voltage application operation, the voltage convergence operation, and the voltage reading operation described in the above-described embodiment, respectively. A series of threshold voltage detection operations consisting of the above is represented, and the threshold voltage detection operations for each row are sequentially executed at different timings so that they do not overlap in time.

  As for the display driving operation (display driving period Tcyc), the display pixel PX (light emission driving circuit DC) for each row of the display panel 210 is also applied to the display panel 210 within one frame period Tfr as in the above-described embodiment. The threshold value of each display pixel PX is detected based on the threshold detection data (threshold compensation data) detected for each display pixel PX (light emission driving switching element) by the threshold voltage detection operation. A precharge operation (precharge period Tth) for writing a precharge voltage Vpre for compensating the voltage, and a write operation (write operation) for writing a grayscale signal (grayscale current Idata, non-light emitting display voltage Vzero) according to display data Light emission operation (light emission) in which each display pixel PX (organic EL element OEL) emits light with a luminance gradation according to the display data (gradation signal) at a predetermined timing and a period of time A work period Tem), a series of drive control consisting sequentially performed at predetermined timing for each row.

  Here, in the timing chart shown in FIG. 17, the hatched portions (indicated as “Tth + Twrt”) indicated by the cross mesh in each row of the display drive period Tcyc are respectively the precharge operation and the write shown in the above-described embodiment. In particular, in the present embodiment, the precharge operation and the write operation for each row are sequentially executed at different timings to display the row where the write operation is completed so that each row does not overlap in time. The light emission operation is executed in order from the pixel PX. That is, among the display driving operations for each row, only the light emitting operation is executed so as to overlap each other in time (partially in parallel).

Hereinafter, the first example of the display driving operation according to the present embodiment will be described in more detail.
As shown in FIG. 17, in the precharge period Tth and the write operation period Twrt (shown as cross mesh in the figure) of the display drive operation (display drive period Tcyc), a specific row is displayed on the display panel 210 from the selection driver 220. By applying an on-level (high level) selection signal Ssel to the selection line SL (for example, the i-th row; 1 ≦ i ≦ 12) as shown in FIG. 7 and FIG. The display pixel PX in the row is set to the selected state. Further, in the precharge period Tth and the write operation period Twrt, a low-potential supply voltage Vsc (= Vs) is applied from the power supply driver 230 to the i-th supply voltage line VL.

  In synchronization with this timing (hereinafter referred to as “selection timing” for convenience), first, in the precharge period Tth, the compensation voltage DAC 150 provided in the data driver 240 is applied to each data line DL. By applying an individual precharge voltage Vpre for compensating a threshold voltage of a switching element (thin film transistor) provided in each display pixel PX (light emission drive circuit DC), each display pixel PX in the i row is applied. A voltage component corresponding to a threshold voltage unique to the switching element (thin film transistor Tr13) is held at the control terminal of the switching element (specifically, between the gate and source terminals of the thin film transistor Tr13; both ends of the capacitor Cs). Accumulated).

  Next, in synchronization with the selection timing, in the write operation period Twrt, each display pixel PX (light emission drive circuit) is applied to the data line DL of each column from the gradation signal generation unit 130 provided in the data driver 240. DC) by separately applying a gradation signal (gradation current Idata or non-emission display voltage Vzero) corresponding to the display data, the control terminal (the switching element of the display pixel PX in each column of the i row) Specifically, a voltage component corresponding to the gradation signal (display data) is held (charge is accumulated or discharged) between the gate and source terminals of the thin film transistor Tr13; both ends of the capacitor Cs.

  Here, as in the drive control method described above, the display data supplied from the display signal generation circuit 260 to the data driver 240 is gray scale display data (other than 0 bits) accompanied by the light emitting operation of the organic EL element (light emitting element) OEL. In the case of the gradation value; gradation display operation), the data driver 240 (gradation signal generation unit 130) generates the gradation current Idata corresponding to the display data and applies it to the display pixel PX in the corresponding column. On the other hand, when the display data is non-light-emitting display data (0-bit gradation value; non-light-emitting display operation) that does not involve the light-emitting operation of the organic EL element (light-emitting element) OEL, the data driver 240. Thus, a predetermined non-light emitting display voltage Vzero is generated and supplied to the display pixels PX in the corresponding column.

  Therefore, in the display pixel PX to which the gradation current Idata is supplied as the gradation signal, each display pixel PX (between the gate and the source of the light emitting driving thin film transistor) is charged by the above-described precharge operation. The voltage component (effective voltage Vdata) based on the gradation current Idata is charged by being added to the voltage component corresponding to the threshold voltage (Vth13).

  Further, in the display pixel PX to which the non-light emitting display voltage Vzero is supplied as the gradation signal, a voltage component corresponding to the threshold voltage (Vth13) charged in each display pixel PX in the row by the precharge operation described above. Almost all (charge) is discharged, and as a result, a voltage (0 V) corresponding to the display data is set in the switching element for driving light emission (between the gate and the source of the thin film transistor).

  Next, as shown in FIG. 17, in the light emission operation period Tem (indicated by dot hatching in the figure) of the display drive operation (display drive period Tcyc), as shown in FIGS. By applying an off level (low level) selection signal Ssel to the selection line SL of the i row, each display pixel PX of the i row is set to a non-selection state. In addition, application of the gradation signal to each data line DL from the gradation signal generation unit 130 provided in the data driver 240 is blocked.

  In synchronism with this timing, a high-potential supply voltage Vsc (= Ve) is applied from the power supply driver 230 to the supply voltage line VL of the i row, whereby each display pixel PX of the i row. A light emission drive current Iem corresponding to display data (gradation signal) is supplied to the organic EL element OEL based on a voltage component charged between the gate and source of the light emission drive thin film transistor, and a predetermined luminance gradation is obtained. A light emitting operation or a non-light emitting operation is performed.

  Here, when the gradation signal written in each display pixel PX is based on gradation display data (gradation value other than 0 bit) accompanied by the light emitting operation of the organic EL element OEL, the organic EL element OEL A light emission driving current Iem equivalent to the gradation current Idata is supplied, and the organic EL element OEL performs a light emission operation (gradation display operation) with a predetermined luminance gradation corresponding to the display data. When based on non-light emitting display data (0-bit gradation value) not accompanied by the light emitting operation of the organic EL element OEL, the light emitting drive current Iem is not supplied to the organic EL element OEL, and the light emitting operation is not performed ( Non-light emitting display operation; black display operation).

  Such a light emission operation (or non-light emission operation) is started in synchronization with the end timing of the precharge operation and the write operation (immediately after the end) in the display pixels PX in the i row, For example, one frame period Tfr is continuously executed until the next precharge operation and write operation start timing (immediately before the start).

  In addition, in synchronization with the end timings of the precharge operation and the write operation for the display pixels PX in the i row (immediately after the end), the same pre-processing as described above is performed for the display pixels PX in the adjacent (i + 1) rows. The charge operation and the write operation are started, and the light emission operation for the (i + 1) row is started in synchronization with the end timing of the precharge operation and the write operation (immediately after the end).

  As a result, as shown in FIG. 17, within one frame period Tfr, each display pixel PX is displayed on the display pixels PX (light emission drive circuit DC) for each row of the display panel 210 by the precharge operation and the write operation. The operation of charging an appropriate voltage component according to the display data (gradation signal) is sequentially executed at different timings so as not to overlap each other in time, and the precharge operation and writing are performed. A drive control operation is executed in which a light emission operation (or no light emission operation) is sequentially performed with a predetermined luminance gradation from the display pixels PX in the row where the operation has been completed so as to partially overlap each other in time. .

  As described above, according to the display device and the drive control method thereof according to the present embodiment, the display drive device and the display pixel corresponding to the above-described drive control method of the current designation gradation method are applied to the data driver and the display panel, respectively. With this configuration, during a normal gradation display operation (other than a non-light-emitting display operation), a light emitting element (organic EL element) is based on the current value of the gradation current according to the display data. The light emission drive current supplied to the display pixel can be controlled, and the current level of the gradation current is converted into a voltage level by a single switching element (light emission drive thin film transistor) provided in each display pixel. Since the current value of the light emission drive current can be set based on the voltage level, a light emission drive switching element (thin film transistor) provided in each display pixel (light emission drive circuit). Device characteristics Njisuta) (without being affected by variation or change with time of the threshold voltage), can be achieved stably desired emission characteristics over a long period of time.

  Further, according to the display device and the drive control method thereof according to the present embodiment, prior to the display data (gradation signal) writing operation to each display pixel and the light emitting operation of the light emitting element (organic EL element). First, for all the display pixels arranged in the display panel, the threshold voltage of the switching element (thin film transistor) for driving light emission provided in the display pixel (light emission driving circuit) is detected and stored (threshold). Value voltage detection operation), and immediately before the display data writing operation to each display pixel, the light emission driving switching element (thin film transistor) provided in the display pixel corresponds to the detected threshold voltage. By applying a precharge voltage (precharge operation) to the control terminal (between the thin film transistor gate and source) of the switching element for light emission driving of each display pixel, Since a voltage component (charge) corresponding to a threshold voltage unique to the switching element can be held (a state in which a threshold voltage changed by a Vth shift is individually compensated), the display data In the writing operation, only the voltage component corresponding to the display data needs to be added and charged, and the voltage component based on the display data can be written quickly and appropriately.

  Therefore, in the drive control method of the current gradation designation method, the voltage component corresponding to the display data can be quickly and quickly even in the display operation at the low luminance gradation where the gradation current corresponding to the display data becomes very small. Since writing can be performed appropriately, the occurrence of insufficient writing in each display pixel can be suppressed, and it is also affected by the Vth shift of the light emission driving switching element (thin film transistor) provided in each display pixel. Therefore, desired image information can be displayed satisfactorily over a long period of time with an appropriate luminance gradation according to the video signal.

  In the non-light-emitting display, a predetermined non-light-emitting display voltage corresponding to display data (0-bit gradation value) is supplied to each display pixel, whereby a switching element for driving light emission (gate-source of a thin film transistor). Can quickly discharge almost all of the voltage components held between them, so that the supply of the light emission drive current to the light emitting element (organic EL element) can be shut off reliably, and the non-light emitting display operation is stable. Can be realized.

  Furthermore, according to the display device and the drive control method thereof according to the present embodiment, in each row of the display panel, in one frame period other than the precharge period and the write operation period, the next precharge period and writing Since the drive control is performed so that the light emission operation continues until the start timing of the insertion operation period, the light emission time of each display pixel (light emitting element) can be set sufficiently long, and image information can be displayed with high light emission luminance. Can do. In other words, this means that image information can be displayed with sufficient luminance even when the light emission luminance of each display pixel is reduced, and thus power consumption for displaying image information can be reduced. .

Next, a second example of the drive control method applicable to the display device according to the present embodiment will be described with reference to the drawings.
FIG. 18 is a timing chart schematically showing a second example of the drive control method for the display device according to the present embodiment. Here, the description of the drive control method equivalent to the above-described first example (see FIG. 17) is simplified. In addition, the hatched portion in the figure shows an operation state equivalent to that of the first example described above. Moreover, FIG. 19 is a principal part block diagram which shows an example of the display apparatus for implement | achieving the 2nd example of the drive control method of the display apparatus which concerns on this embodiment. Here, the same components as those of the display device described in the above-described embodiment will be described with the same reference numerals.

  As shown in FIG. 18, in the second example of the drive control operation of the display device 200 according to the present embodiment, first, as in the first example described above, all the display pixels PX arranged in the display panel 210. Then, the threshold voltage detection operation is sequentially executed for each row at a predetermined timing, and thereafter, within one frame period Tfr (about 16.7 msec), the display pixels PX (light emission drive circuit DC) for each row of the display panel 210 are displayed. ), After the above threshold voltage is compensated, an operation (“Tth + Twrt” in the figure) for writing a gradation signal (gradation current Idata, non-light emitting display voltage Vzero) according to display data is performed on all rows. A display driving operation in which a plurality of rows of display pixels PX (organic EL elements OEL) that are grouped in advance are simultaneously light-emitted with a luminance gradation corresponding to the display data (gradation signal) at a predetermined timing. By executing the display drive period Tcyc), image information of the display panel 210 one screen is displayed.

  Here, in the second example of the display drive operation according to the present embodiment, specifically, first, all the display pixels PX arranged in the display panel 210 are grouped in advance for each of a plurality of rows. For example, as shown in FIG. 18, 12 rows of display pixels PX constituting the display panel 210 are arranged in 4 rows such as the 1st to 4th rows, the 5th to 8th rows, and the 9th to 12th rows adjacent to each other. Minute display pixels PX are grouped as a set.

  Then, within one frame period Tfr, the precharge operation and the write operation are sequentially performed with respect to the display pixels PX (light emission drive circuit DC) for each row of the display panel 210 at different timings. Next, in each of the above groups, the light emission operation is performed for the group in which the writing operation to the display pixels PX of all the rows included in the group is completed.

  For example, in a group in which the display pixels PX in the first to fourth rows are set as one set, the precharge operation and the writing operation are sequentially performed from the display pixels PX in the first row, and the display pixels PX in the fourth row are performed. At the timing when the writing operation is completed, the display pixels PX for the four rows in the group simultaneously emit light based on the display data (gradation signal) written to each display pixel PX. This light emitting operation is continued until the next precharge operation and writing operation are started for the display pixels PX in the first row.

  In addition, at the timing when the writing operation is completed for the display pixels PX in the fourth row, the precharge is sequentially performed from the display pixels PX in the fifth row in a group including the display pixels PX in the fifth to eighth rows. An operation and a write operation are performed. Thereafter, the same operation is repeatedly executed until the writing operation is completed for the display pixels PX in the 12th row of the next group.

  As described above, the precharge operation and the write operation are sequentially executed for each row at a predetermined timing, and the write operation is completed for the display pixels PX of all rows included in the group for each preset group. At that time, all the display pixels PX in the group are driven and controlled to emit light simultaneously. Therefore, in the display drive operation according to the second example, during the period in which the precharge operation and the write operation are performed on the display pixels PX in other rows of the same group, all of the groups in the group are performed. Control is performed so that the display pixel is set to the non-light emitting display state (black display state) by performing the non-light emitting operation.

  For example, as shown in FIGS. 7 and 12, such a display driving operation is applied to the supply voltage line VL of the row by the power supply driver 230 during the precharge operation and the write operation. The low-potential supply voltage Vsc (= Vs) is continuously applied during the period in which the precharge operation and the write operation are performed on the display pixels PX in the rows included in the same group, and all of those included in the group are included. This is realized by controlling the supply voltage Vsc (= Ve) of a high potential to be applied to the supply voltage line VL of all the rows of the group after the precharge operation and the write operation for the row of the group are completed. be able to.

  Further, the same drive control is performed by branching a single supply voltage line VL, for example, as shown in FIG. 19 so that a single supply voltage Vsc is simultaneously applied to each group. A configuration in which the display pixels PX in the rows (or the 5th to 8th rows and the 9th to 12th rows) are connected in common is applied, and the single supply voltage Vsc applied from the power supply driver 230 is in the same group. It can also be realized by being applied to the display pixels PX in all the included rows. Also in this embodiment, as in the case shown in FIG. 16, individual selection lines SL are provided for each row of the display panel 210, and individual selection signals Ssel are applied from the selection driver 220 at different timings. The

  Therefore, according to the drive control method (display drive operation) of such a display device, it is possible to obtain the same operation effect as the drive control method according to the first example described above, and display of each row in the same group. During the period in which the precharge operation and the write operation are performed on the pixel, the light emission operation of the display pixel (light emitting element) is not performed, and the non-light emission operation (black display operation) is performed. In the moving image display operation by continuous display, flickering of the moving image can be suppressed and the sharpness can be improved.

  Here, in the timing chart shown in FIG. 18, the 12 rows of display pixels PX constituting the display panel 210 are grouped into three groups, and the light emission operation is executed simultaneously at different timings for each group. Therefore, the ratio (black insertion rate) of the black display period by the non-light emission operation in one frame period Tfr is approximately 33%. Here, in order to visually recognize a moving image clearly without flickering in human vision, it is generally a guideline that the black insertion rate is approximately 30% or more. Thus, a display device having a good display image quality can be realized.

Next, a third example of the drive control method applicable to the display device according to the present embodiment will be described with reference to the drawings.
FIG. 20 is a timing chart schematically showing a third example of the drive control method for the display device according to the present embodiment. Here, the description of the drive control method equivalent to the above-described second example (see FIG. 18) is simplified.

  As shown in FIG. 20, the third example of the drive control operation of the display device 200 according to the present embodiment is arranged on the display panel 210 prior to the display drive operation, as in the second example described above. For all the display pixels PX, the threshold voltage detection operation is sequentially performed at a predetermined timing for each row, and then arranged in the display panel 210 within one frame period Tfr (about 16.7 msec) and not adjacent to each other. Display driving operation for sequentially executing the precharge operation and the writing operation at different timings for the display pixels PX in each row included in a specific group in each group of display pixels PX in a plurality of rows. Are sequentially executed for each group.

  Here, in the display driving operation according to the present embodiment, specifically, all the display pixels PX arranged in the display panel 210 are, for example, arranged in 12 rows constituting the display panel 210 as shown in FIG. Display pixels PX, a set of four rows of display pixels PX, such as rows 1, 4, 7, 10, 2, 5, 8, 11, 11, 3, 6, 9, 12 Divided into three groups.

  For example, in the group including the display pixels PX in the first, fourth, seventh, and tenth rows as a set, the precharge operation and the writing operation are executed in order from the display pixel PX in the first row, and the display in the tenth row At the timing when the writing operation is completed for the pixels PX, the display pixels PX for the four rows of the group simultaneously emit light based on the display data (gradation signal) written to each display pixel PX. This light emitting operation is continued until the next precharge operation and writing operation are started for the display pixels PX in the first row.

  In addition, at the timing when the writing operation is completed for the display pixel PX on the 10th row, in the group including the display pixels PX on the 2nd, 5th, 8th, and 11th rows as a set, the display pixels PX on the 2nd row are sequentially arranged. The precharge operation and the write operation are performed. Thereafter, the same operation is repeatedly executed until the writing operation is completed for the display pixels PX in the 12th row of the next group.

  In this way, for each row of each group, the precharge operation and the write operation are sequentially executed at a predetermined timing, and when the write operation is completed on the display pixels PX of all the rows included in the group, Drive control is performed so that all the display pixels PX of the group are caused to emit light at the same time. Therefore, also in the display driving operation according to the third example, the precharge operation and the writing operation are performed on the display pixels PX in other rows of the same group, as in the second example described above. During the period, all the display pixels in the group are controlled to perform a non-light emitting display operation (black display operation).

  Further, such a display driving operation is performed, for example, during a period in which the precharge operation and the writing operation are performed on the display pixels PX in other rows of the same group, as in the second example described above. The supply voltage Vsc applied from the power supply driver 230 to the supply voltage line VL of each row in the group is held at a low potential (Vs), and the precharge operation and writing are performed on the display pixels PX in all rows of the same group. After the operation is completed, the control can be realized by applying a high potential supply voltage Vsc (= Ve) to the supply voltage lines VL of all the rows included in the group. As in the second example (see FIG. 19) described above, the supply voltage line VL is applied so that the single supply voltage Vsc is applied to the display pixels PX in all rows included in each group. A configuration may be applied in which these are branched and arranged.

  Therefore, according to the drive control method (display drive operation) of such a display device, similarly to the drive control method according to the second example described above, a plurality of 12 rows of display pixels PX constituting the display panel 210 are provided. The group is divided into groups and controlled so that the light emission operation is executed simultaneously at different timings for each group. Therefore, the non-light emission operation (black display operation) is executed for a predetermined period during one frame period Tfr. . In particular, in this drive control method, the ratio of the black display period (black insertion rate) by the non-light emitting operation can be set to approximately 33%, so that the flicker of the moving image is suppressed and the sharpness is improved. A display device can be realized.

  In the drive control methods according to the second and third examples described above, the case where the display pixels PX constituting the display panel 210 are grouped into three groups has been described, but the present invention is limited to this. Needless to say, for example, the number of groups may be appropriately increased or decreased.

Below, the modification of the drive control method which concerns on the 2nd, 3rd example mentioned above is shown.
FIG. 21 is a timing chart schematically showing a modification (No. 1) of the second example of the drive control method for the display device according to the present embodiment, and FIG. 22 is a display according to the present embodiment. 6 is a timing chart schematically showing a modification (No. 1) of the third example of the drive control method of the apparatus. FIG. 23 is a timing chart schematically showing a modification (No. 2) of the second example of the drive control method for the display device according to the present embodiment, and FIG. 12 is a timing chart schematically showing a modification (No. 2) of the third example of the drive control method of the display device.

  In the modification (part 1) of the drive control method for the display device according to the second and third examples described above, for example, as shown in FIGS. 21 and 22, the display pixels PX constituting the display panel 210 are Divided into 4 groups (4 groups of 1st to 3rd lines, 4th to 6th lines, 7th to 9th lines, 10th to 12th lines in FIG. 21, 1st, 5th, 9th lines, 2 , 6, 10th row, 3rd, 7th, 11th row, 4th, 8th, and 12th row), the light emission operation is controlled at different timings for each group. In this case, the ratio (black insertion rate) of the black display period due to the non-light emission operation in one frame period Tfr is 25%, which is slightly lower than 30%, which is a guideline that the above-mentioned flickering of moving images is not visually recognized. A display device having a good display image quality can be realized.

  Further, in the modification (No. 2) of the drive control method for the display device according to the second and third examples described above, for example, as shown in FIGS. 23 and 24, the display pixel PX constituting the display panel 210 is displayed. Are divided into two groups (in FIG. 23, 2 groups in the 1st to 6th rows and the 7th to 12th rows, in FIG. 24, 2 groups in the odd and even rows) at different timings for each group. Control to execute the light emission operation all at once. In this case, the ratio (black insertion rate) of the black display period due to the non-light emission operation in one frame period Tfr is 50%, which is higher than 30%, which is a guideline that the above-described flickering of moving images is not visually recognized. Since the period is only half of one frame period Tfr, the image information cannot be displayed with sufficient light emission luminance. Thus, by appropriately increasing the light emission luminance of each display pixel, the image information can be displayed with sufficient luminance and good display image quality.

Next, a fourth example of the drive control method applicable to the display device according to the present embodiment will be described with reference to the drawings.
FIG. 25 is a timing chart schematically showing a fourth example of the drive control method for the display device according to the present embodiment. Here, the description of the drive control method equivalent to the above-described first to third examples (see FIGS. 17 to 24) is simplified. FIG. 26 is a main part configuration diagram showing an example of a display device for realizing a fourth example of the display device drive control method according to the present embodiment. Here, the same components as those of the display device described in the above-described embodiment will be described with the same reference numerals.

  As shown in FIG. 25, the fourth example of the drive control operation of the display device 200 according to the present embodiment is performed on the display panel 210 prior to the display drive operation, as in the first to third examples described above. For all the display pixels PX arranged, the threshold voltage detection operation is sequentially executed for each row at a predetermined timing, and then the first half of one frame period Tfr (about 16.7 msec) (1/2 of one frame period Tfr). ), The precharge operation and the write operation are sequentially performed on the display pixels PX in each row arranged in the display panel 210 at different timings, and the latter half of one frame period Tfr (one frame period Tfr). The display driving operation is performed in which the display pixels PX of all the rows arranged in the display panel 210 are simultaneously light-emitted with the luminance gradation corresponding to the display data.

  As described above, when the writing operation is completed for the display pixels PX in all rows, the precharge operation and the writing operation are performed by controlling the drive so that all the display pixels PX emit light simultaneously. During this period, no light emission operation is performed in any row of the display pixels PX, and all the display pixels PX are controlled to perform a non-light emission display operation (black display operation).

  Such a display driving operation is applied to the supply voltage lines VL of all the rows from the power supply driver 230, for example, during the period in which the precharge operation and the writing operation are performed on the display pixels PX of each row. After the supply voltage Vsc is kept at a low potential (Vs) and the precharge operation and the write operation for the display pixels PX in all rows are completed, the supply voltage Vsc of a high potential is applied to the supply voltage line VL in all rows. It can be realized by controlling to apply (= Ve).

  Similar drive control is performed so that a single supply voltage Vsc is applied to all the display pixels PX at the same time. For example, as shown in FIG. 26, a single supply voltage line VL corresponds to all rows. A configuration in which all the display pixels PX arranged in the display panel 210 are shared and connected is applied, and a single supply voltage Vsc applied from the power supply driver 230 is applied to the display pixels PX in all rows. It can also be realized by being applied to. In this case, the configuration of the power supply driver 230 is such that a high-potential supply voltage Vsc (= Ve) and a low-potential supply voltage Vsc (= Vs) are determined at a predetermined timing based on, for example, a power supply control signal supplied from the system controller 250. Therefore, at least the shift register circuit as shown in FIG. 16 is not necessarily provided. Also in this embodiment, as in the case shown in FIG. 16, individual selection lines SL are provided for each row of the display panel 210, and individual selection signals Ssel are applied from the selection driver 220 at different timings. The

  Therefore, according to the drive control method (display drive operation) of such a display device, the display drive period (one frame period Tfr) is divided into the first half and the second half, and the display pixels in each row are sequentially precharged in the first half. Since the operation and the writing operation are executed and all the display pixels are controlled to perform the light emission operation at the same time in the second half, the ratio of the black display period by the non-light emission operation in one frame period Tfr (black insertion rate) 50%, which exceeds 30%, which is an indication that the above-mentioned flickering of moving images is not visually recognized, but because the light emission operation period is only half of one frame period Tfr, image information is displayed with sufficient light emission luminance. In addition, since the precharge period and the write operation period (particularly, the write operation period) in each row are shortened, a sufficient time for writing display data (grayscale signal) is ensured. Although there is a possibility that the image information will not be displayed, by appropriately increasing the light emission luminance of each display pixel and further increasing the current value of the gradation current, the image information is displayed with sufficient luminance and good display image quality. be able to.

1 is a main part configuration diagram showing an embodiment of a display driving device according to the present invention and a display pixel driven and controlled by the display driving device. 6 is a timing chart showing a threshold voltage detection operation in the display driving apparatus according to the embodiment. It is a conceptual diagram which shows the voltage application operation | movement in the display drive device which concerns on this embodiment. It is a conceptual diagram which shows the voltage convergence operation | movement in the display drive device which concerns on this embodiment. It is a conceptual diagram which shows the voltage reading operation | movement in the display drive device which concerns on this embodiment. FIG. 6 is a diagram illustrating an example of a drain-source current characteristic when an n-channel thin film transistor has a gate-source voltage set to a predetermined condition and a drain-source voltage is modulated. 6 is a timing chart showing a drive control method (gradation display operation) in the display drive device according to the present embodiment. It is a conceptual diagram which shows the precharge operation | movement in the display drive device which concerns on this embodiment. It is a conceptual diagram which shows the data writing operation | movement in the display drive device which concerns on this embodiment. It is a conceptual diagram which shows the light emission operation | movement in the display drive device which concerns on this embodiment. It is a principal part block diagram which shows the other structural example of the display drive device which concerns on this embodiment. It is a timing chart which shows the drive control method (non-light emission display operation | movement) in the display drive device which concerns on this embodiment. It is a conceptual diagram which shows the other example of the data writing operation | movement in the display drive device which concerns on this embodiment. It is a conceptual diagram which shows the no light emission operation | movement in the display drive device which concerns on this embodiment. It is a schematic block diagram which shows an example of the whole structure of the display apparatus which concerns on this invention. It is a schematic block diagram which shows an example of the display panel applied to the display apparatus which concerns on this embodiment, and its peripheral circuit (selection driver, power supply driver). 2 is a timing chart schematically showing a first example of a drive control method for a display device according to the present embodiment. 6 is a timing chart schematically showing a second example of the display device drive control method according to the embodiment. It is a principal part block diagram which shows an example of the display apparatus for implement | achieving the 2nd example of the drive control method of the display apparatus which concerns on this embodiment. 5 is a timing chart schematically showing a third example of the display device drive control method according to the embodiment. 6 is a timing chart schematically showing a modification (No. 1) of the second example of the drive control method for the display device according to the embodiment. 10 is a timing chart schematically showing a modification (No. 1) of the third example of the drive control method for the display device according to the embodiment. 6 is a timing chart schematically showing a modification (No. 2) of the second example of the drive control method for the display device according to the embodiment. 10 is a timing chart schematically showing a modification (No. 2) of the third example of the drive control method for the display device according to the embodiment. 6 is a timing chart schematically showing a fourth example of the display device drive control method according to the embodiment. It is a principal part block diagram which shows an example of the display apparatus for implement | achieving the 4th example of the drive control method of the display apparatus which concerns on this embodiment. It is a schematic block diagram which shows the principal part of the voltage control active matrix light emitting element type display in a prior art. It is an equivalent circuit diagram which shows the structural example of the display pixel (light emission drive circuit and light emitting element) applicable to the light emitting element type display in a prior art.

Explanation of symbols

PX display pixel DC light emission drive circuit SL selection line DL data line VL supply voltage line Tr11 to Tr13 thin film transistor Cs capacitor OEL organic EL element 100 display drive device 110 shift register / data register unit 120 display data latch unit 130 gradation signal generation unit 140 Detection voltage ADC
150 Compensation voltage DAC
160 Threshold Data Latch Unit 170 Frame Memory 180 Data Line Input / Output Switching Unit 200 Display Device 210 Display Panel 220 Selection Driver 230 Power Driver 240 Data Driver 250 System Controller 260 Display Signal Generation Circuit

Claims (45)

A gradation signal is supplied to a display pixel including a current control type light emitting element and a light emitting driving element that supplies a light emission driving current to the light emitting element, thereby causing the light emitting element to emit light at a predetermined luminance gradation. In the display driving device,
at least,
Gradation signal generating means for generating the gradation signal and supplying the gradation signal to the display pixels;
Threshold voltage detecting means for detecting a threshold voltage specific to the light emitting drive element provided in the display pixel;
Storage means for storing threshold data associated with the threshold voltage detected by the threshold voltage detection means;
Compensation voltage applying means for applying a compensation voltage for compensating the threshold voltage of the light emission drive element to the light emission drive element based on the threshold data stored in the storage means;
A display driving device comprising: The display driving device further includes detection voltage applying means for applying a threshold detection voltage higher than the threshold voltage to the light emission driving element,
After the threshold voltage detection means is applied with the threshold voltage detection voltage to the light emission drive element, and a part of the electric charge corresponding to the threshold voltage detection voltage is discharged and converged, The display driving device according to claim 1, wherein the voltage is detected as the threshold voltage of the light emission driving element. The compensation voltage applying means generates the compensation voltage for causing the light emission driving element to hold a voltage component corresponding to the threshold voltage, based on the threshold data stored in the storage means, The display driving device according to claim 1, wherein the display driving device is applied to the light emitting driving element. The light emission drive element provided in the display pixel includes a current path for passing the light emission drive current to the light emission element, and a control terminal for controlling a supply state of the light emission drive current,
The detection voltage applying means applies the threshold detection voltage between the control terminal of the light emission drive element and one end side of the current path, and the threshold voltage detection means 4. The display driving device according to claim 2, wherein a potential difference between the control terminal of the light emitting driving element and one end side of the current path is detected as the threshold voltage. The compensation voltage applying means applies the compensation voltage based on the threshold data stored in the storage means between the control terminal of the light emission driving element and one end side of the current path. The display driving device according to claim 4. The threshold voltage detection means comprises means for converting the threshold voltage of the light emitting drive element detected as an analog signal into a digital signal,
6. The display driving apparatus according to claim 1, wherein the storage unit stores the threshold voltage converted into the digital signal as the threshold data. The compensation voltage applying means generates the compensation voltage composed of an analog signal for compensating the threshold voltage of the light emitting drive element based on the threshold data stored as a digital signal in the storage means. The display driving apparatus according to claim 6, further comprising: The gradation signal generating means includes means for generating a gradation current having a predetermined current value for causing the light emitting element to emit light at a predetermined luminance gradation as the gradation signal. The display driving device according to claim 1. 2. The gradation signal generating means includes means for generating a non-light emitting display voltage having a predetermined voltage value for causing the light emitting element to perform a non-light emitting operation as the gradation signal. The display driving device according to any one of 1 to 8. The display driving device further includes data acquisition means for sequentially acquiring and holding luminance gradation data for generating the gradation signal for each of the display pixels provided in a predetermined arrangement. Prepared,
The gradation signal generation unit generates the gradation signal corresponding to the luminance gradation data for each of the plurality of display pixels held in the data acquisition unit, and the gradation signal generation unit generates the gradation signal for each of the plurality of display pixels. The display driving device according to claim 1, wherein a gradation signal is supplied. The display driving device individually captures and sequentially transfers threshold value data associated with the threshold voltage detected from the display pixels provided in a plurality in a predetermined arrangement. Further,
The storage means individually associates the threshold data associated with the threshold voltage for each of the plurality of display pixels transferred from the threshold acquisition means in association with each of the plurality of display pixels. The display driving device according to claim 1, wherein the display driving device is stored in the display driving device. The data acquisition means and the threshold acquisition means share a configuration in which the luminance gradation data is sequentially and individually acquired, and a configuration in which the threshold data is individually acquired and sequentially transferred. The display driving apparatus according to claim 11, wherein The display driving device includes at least a signal path for detecting the threshold voltage of the display pixel by the threshold voltage detecting unit, a signal path for applying the compensation voltage to the display pixel by the compensation voltage applying unit, And selectively switching the connection between a signal path for supplying the gradation signal to the display pixel by the gradation signal generating means and a single data line provided corresponding to the display pixel. 13. The display driving device according to claim 1, further comprising a signal path switching unit. In the display driving device, a signal path for applying the threshold detection voltage to the display pixel by the detection voltage applying unit is selectively connected to the single data line. The display driving apparatus according to claim 13, wherein the display driving apparatus is configured. A gradation signal is supplied to a display pixel including a current control type light emitting element and a light emitting driving element that supplies a light emission driving current to the light emitting element, thereby causing the light emitting element to emit light at a predetermined luminance gradation. In the drive control method of the display drive device,
at least,
A first step of detecting a threshold voltage specific to the light emitting drive element and storing the threshold voltage in the storage means as threshold data associated with the threshold voltage;
Applying a compensation voltage for compensating the threshold voltage of the light emission drive element to the light emission drive element based on the threshold data stored in the storage means;
A third step of supplying the gradation signal to the display pixel, and holding the voltage component based on the gradation signal on top of the voltage component based on the compensation voltage applied to the light emitting drive element;
A drive control method for a display drive device, comprising: 16. The drive control method for a display drive device according to claim 15, wherein the first step is executed at an arbitrary timing prior to the second step and the third step. The first step includes a step of applying a threshold detection voltage higher than the threshold voltage to the light emitting drive element, and a charge corresponding to the threshold voltage detection voltage. 17. The drive control method for a display drive device according to claim 15, further comprising: detecting a voltage after the unit is discharged and converged as the threshold voltage of the light emission drive element. The first step further includes a step of storing the threshold value data generated by converting the threshold voltage of the light emission driving element detected as an analog signal into a digital signal in the storage means. 18. The drive control method for a display drive device according to claim 17, The second step generates a voltage for compensating the threshold voltage of the light emission driving element based on the threshold data stored in the storage means, and uses the light emission driving element as the compensation voltage. The display drive device drive control method according to claim 15, wherein the display drive device drive control method is applied to the display drive device. The second step generates the compensation voltage composed of an analog signal for compensating the threshold voltage of the light emission drive element based on the threshold data stored as a digital signal in the storage means. The drive control method of the display drive device of Claim 18 or 19 characterized by these. In the third step, when the light emitting element is operated to emit light at a predetermined luminance gradation, a gradation current having a predetermined current value is generated as the gradation current, and the light emitting element is operated without emitting light. 21. The display driving device according to claim 15, wherein a non-light emitting display voltage having a predetermined voltage value is generated as the gradation signal and supplied to the display pixel. Drive control method. At least an operation of applying the threshold detection voltage to the display pixel in the first step, an operation of detecting the threshold voltage of the display pixel in the first step, and the second An operation for applying the compensation voltage to the display pixel in the step and an operation for supplying the gradation signal to the display pixel in the third step. The method for controlling driving of a display driving device according to any one of claims 15 to 21, wherein the method is selectively executed via a data line. A plurality of display pixels each including a current control type light emitting element and a light emitting driving element for supplying a light emitting driving current to the light emitting element at each intersection of a plurality of selection lines and data lines arranged in a row direction and a column direction In a display device comprising a display panel in which are arranged,
A selection driving unit configured to sequentially apply a selection signal to the display pixels for each row of the display panel at a predetermined timing to set a selection state;
A data driver that generates a gradation signal corresponding to display data for displaying desired image information and supplies the gradation signal to the display pixels in a row set in the selected state;
With
The data driver is at least
Gradation signal generating means for individually supplying the gradation signal to each of the display pixels via the data line;
Threshold voltage detection means for individually detecting a threshold voltage specific to the light emission drive element of each display pixel;
Storage means for storing threshold data associated with the threshold voltage detected by the threshold voltage detection means for each display pixel;
Compensation voltage applying means for individually applying a compensation voltage for compensating the threshold voltage for each display pixel to the light emitting drive element of the display pixel based on the threshold data stored in the storage means When,
A display device comprising: The data driver further comprises detection voltage applying means for individually applying a threshold detection voltage higher than the threshold voltage to the light emission drive element of the display pixel,
24. The display device according to claim 23, wherein the threshold voltage detection unit individually detects a threshold voltage of the light emission drive element after the threshold voltage detection voltage has converged. . The compensation voltage applying means generates the compensation voltage for causing the light emission driving element to hold a voltage component corresponding to the threshold voltage, based on the threshold data stored in the storage means, The display device according to claim 23, wherein the display device is individually applied to the light emission drive element of the display pixel. The light emission drive element provided in each of the display pixels includes a current path through which the light emission drive current flows to the light emitting element, and a control terminal for controlling a supply state of the light emission drive current,
The detection voltage applying means applies the threshold detection voltage between the control terminal of the light emission drive element and one end side of the current path, and the threshold voltage detection means 26. The potential difference between the control terminal of the light emitting drive element and one end side of the current path when no current flows in the current path is detected as the threshold voltage. The display device described. The compensation voltage applying means applies the compensation voltage based on the threshold data stored in the storage means between the control terminal of the light emission driving element and one end side of the current path. The display device according to claim 26. The threshold voltage detection means includes means for converting the threshold voltage of the light emitting drive element detected as an analog signal into a digital signal and generating the threshold data,
The compensation voltage applying means generates the compensation voltage composed of an analog signal for compensating the threshold voltage of the light emitting drive element based on the threshold data stored as a digital signal in the storage means. The display device according to any one of claims 23 to 27, further comprising: The gradation signal generating means generates, as the gradation signal, a gradation current having a predetermined current value for causing the light emitting element to emit light at a predetermined luminance gradation, and the light emitting element emits no light. 29. A display device according to claim 23, further comprising: a non-light emitting display voltage having a predetermined voltage value for operating. The data driver is
Threshold value acquisition means for individually capturing and sequentially transferring the threshold data associated with the threshold voltage detected from each of the display pixels;
Data acquisition means for sequentially capturing and holding luminance gradation data for generating the gradation signal for each of the display pixels individually;
Further,
The storage means individually associates the threshold data associated with the threshold voltage for each of the plurality of display pixels transferred from the threshold acquisition means in association with each of the plurality of display pixels. Remember
The gradation signal generation unit generates the gradation signal according to the luminance gradation data for each of the plurality of display pixels held in the data acquisition unit, and for each of the plurality of display pixels, 30. The display device according to claim 23, wherein the gradation signal is supplied. The data acquisition means and the threshold acquisition means share a configuration in which the luminance gradation data is sequentially and individually acquired, and a configuration in which the threshold data is individually acquired and sequentially transferred. 31. A display device according to claim 30, characterized in that: The data driver includes at least a signal path for detecting the threshold voltage of the display pixel by the threshold voltage detection unit, a signal path for applying the compensation voltage to the display pixel by the compensation voltage application unit, And selectively switching the connection between a signal path for supplying the gradation signal to the display pixel by the gradation signal generating means and a single data line provided corresponding to the display pixel. 32. The display device according to claim 23, further comprising a signal path switching unit. The data driver may be configured such that a signal path for applying the threshold detection voltage to the display pixel by the detection voltage applying unit is selectively connected to the single data line. The display device according to claim 32, wherein the display device is configured. The display device further includes a power supply driving unit that applies a predetermined supply voltage to each of the display pixels,
The power supply driver sequentially applies the supply voltage to the display pixels for each row of the display panel at a predetermined timing, and sets the display pixels in a light emitting operation state for each row. Item 34. The display device according to any one of Items 23 to 33. The display device further includes a power supply driving unit that applies a predetermined supply voltage to each of the display pixels,
The power supply unit sequentially applies the supply voltage at a predetermined timing to the display pixels for each group obtained by grouping the plurality of display pixels arranged in the display panel into a plurality of rows. The display device according to claim 23, wherein the display pixel is set in a light emitting operation state for each group. Each of the display pixels includes a light emission driving circuit that controls a light emission operation of the light emitting element,
The light emission driving circuit includes at least a first switch means in which the supply voltage is applied to one end of a current path and a connection contact with the light emitting element is connected to the other end of the current path, and a control terminal is the selection A second switch means connected to the line, the supply voltage being applied to one end of the current path, and the control terminal of the first switch means being connected to the other end of the current path, and the control terminal being the selection line A third switch means connected to the one end of the current path, the data line connected to one end of the current path, and the connection contact connected to the other end of the current path,
The light emission driving element is the first switch means;
The detection voltage applying means applies the threshold detection voltage between the control terminal of the first switch means and the connection contact,
The threshold voltage detecting means detects a potential between the control terminal of the first switch means and the connection contact as the threshold voltage;
The compensation voltage applying means applies the compensation voltage based on the threshold data stored in the storage means between the control terminal of the first switch means and the connection contact. The display device according to any one of claims 23 to 35. 37. The display device according to claim 36, wherein each of the first to third switch means is a field effect transistor having a semiconductor layer made of amorphous silicon. 38. The display device according to claim 23, wherein the light emitting element is an organic electroluminescence element. A display panel in which a plurality of display pixels each having a current control type light emitting element are arranged at each intersection of a plurality of selection lines and data lines arranged in a row direction and a column direction, and the display panel at a predetermined timing A selection drive unit that sequentially applies a selection signal to the display pixels for each row to set the selection state, and generates a gradation signal according to display data for displaying desired image information, and the selection state A data driving unit that supplies the display pixels in the row set to the row, and the data driving unit supplies the grayscale signal to each of the display pixels, thereby causing the display pixels to have a predetermined luminance gradation. In the drive control method of the display device that displays the desired image information on the display panel by performing a light emitting operation at
at least,
A light emission driving element that is provided in each of the display pixels and supplies a light emission driving current having a predetermined current value to the light emitting element based on the grayscale signal, than a threshold voltage specific to the light emission driving element. A detection voltage application step of individually applying a high potential threshold detection voltage;
After the threshold voltage detection voltage has converged, the threshold voltage of the light emitting drive element is individually detected, and threshold data associated with the threshold voltage is obtained for each display pixel. A threshold voltage detecting step for storing in the storage means;
Based on the threshold value data stored in the storage means, a compensation voltage for compensating the threshold voltage of the light emission drive element is generated for each display pixel, and is individually applied to the light emission drive element. And a compensation voltage applying step for holding the voltage component,
The gradation signal corresponding to the display data is supplied to each of the display pixels, and the voltage component based on the gradation signal is added to the voltage component based on the compensation voltage applied to the light emission driving element. A data writing step to hold;
The light emission drive current generated based on the voltage component held in the light emission drive element of each display pixel is supplied to each of the light emission elements to cause the light emission element to emit light at a predetermined luminance gradation. A flash control step;
A drive control method for a display device, comprising: In the detection voltage application step and the threshold voltage detection step, the compensation voltage application step, the data writing step, and the gradation light emission step are performed at an arbitrary timing prior to all of the above-described array arranged on the display panel. 40. The display device drive control method according to claim 39, wherein the method is executed for display pixels. The display device according to claim 40, wherein the detection voltage application step and the threshold voltage detection step are sequentially executed for each row with respect to the display pixels arranged in the display panel. Drive control method. The compensation voltage applying step and the data writing step are sequentially executed for each row with respect to the plurality of display pixels arranged on the display panel, and the gradation light emitting step includes the compensation voltage applying step and 40. The drive control method for a display device according to claim 39, wherein the data writing step is sequentially executed from the completed row. The compensation voltage applying step and the data writing step are sequentially executed for each group obtained by grouping the plurality of display pixels arranged in the display panel into a plurality of rows, and the gradation light emitting step includes 40. The drive control method for a display device according to claim 39, wherein the compensation voltage application step and the data writing step are sequentially executed from the group that has finished. In the data writing step, when the light emitting element is operated to emit light at a predetermined luminance gradation, a gradation current having a predetermined current value is supplied to the display pixel as the gradation signal, and the light emitting element is 44. The display device drive according to claim 39, wherein, in a non-light emitting operation, a non-light emitting display voltage having a predetermined voltage value is supplied to the display pixel as the gradation signal. Control method. Single data provided corresponding to each of the display pixels, at least the detection voltage applying step, the threshold voltage detecting step, the compensation voltage applying step, and the data writing step. 45. The drive control method for a display device according to claim 39, wherein the method is selectively executed via a line.

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