JP2003202837A - Device and method for driving display panel - Google Patents

Device and method for driving display panel

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Publication number
JP2003202837A
JP2003202837A JP2001401815A JP2001401815A JP2003202837A JP 2003202837 A JP2003202837 A JP 2003202837A JP 2001401815 A JP2001401815 A JP 2001401815A JP 2001401815 A JP2001401815 A JP 2001401815A JP 2003202837 A JP2003202837 A JP 2003202837A
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JP
Japan
Prior art keywords
current value
light
value
driving
current
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Pending
Application number
JP2001401815A
Other languages
Japanese (ja)
Inventor
Shinichi Ishizuka
Hideo Ochi
Tsuyoshi Sakamoto
Masami Tsuchida
正美 土田
強 坂本
真一 石塚
英夫 越智
Original Assignee
Pioneer Electronic Corp
パイオニア株式会社
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Pioneer Electronic Corp, パイオニア株式会社 filed Critical Pioneer Electronic Corp
Priority to JP2001401815A priority Critical patent/JP2003202837A/en
Priority claimed from US10/322,776 external-priority patent/US7274363B2/en
Priority claimed from CN 02828406 external-priority patent/CN1703731B/en
Publication of JP2003202837A publication Critical patent/JP2003202837A/en
Pending legal-status Critical Current

Links

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method and device for driving display panel capable of always maintaining a brightness level of an entire screen within a certain range while preventing unevenness of brightness in the screen. <P>SOLUTION: A light emission driving current value flowing at the time of making each light emitting element bearing each pixel emit light sequentially and individually is measured in advance correspondingly to each pixel, and based on the above light emission driving current value made to correspond to the pixel corresponding to an input pixel data the input pixel data are subjected to the correction of brightness, and also a value of a driving voltage to be supplied to each light emitting element is adjusted so that one of the individual light emission driving currents measured is equal to a predetermined reference current value. <P>COPYRIGHT: (C)2003,JPO

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a driving device and a driving method for an active matrix type display panel.

[0002]

2. Description of the Related Art At present, an electroluminescence display device (hereinafter, referred to as an EL display device) equipped with a display panel using an organic electroluminescence device (hereinafter, simply referred to as an EL device) as a light-emitting device for carrying out a pixel is known. Attention has been paid. As a driving method of the display panel by the EL display device, a simple matrix driving type and an active matrix driving type are known.
The active matrix drive type EL display device has advantages such as lower power consumption and less crosstalk between pixels than a simple matrix type, and is particularly suitable for a large screen display and a high definition display. Are suitable.

FIG. 1 shows an active matrix drive type E.
It is a figure showing the schematic structure of L display device. As shown in FIG. 1, the EL display device includes a display panel 10.
And a driving device 100 for driving the display panel 10 according to a video signal. The display panel 10 includes:
Anode power supply line 16, cathode power supply line 17, 1 screen n
Scanning lines (scanning electrodes) A for each horizontal scanning line
1 to A n, and m data lines (data electrodes) B 1 .about.B m arranged in intersecting each scanning line are respectively formed. The drive voltage Vc is applied to the anode power supply line 16, and the ground potential GND is applied to the cathode power supply line 17. Furthermore, at each intersection of the scanning lines A 1 to A n and the data lines B 1 .about.B m in the display panel 10, EL unit E 1 serving as pixels, 1 through E n, m are formed.

FIG. 2 is a diagram showing an example of the internal configuration of an EL unit E formed at the intersection of one scanning line A and one data line B. In FIG. 2, a scanning line A is connected to a gate G of a scanning line selecting FET (Field Effect Transistor) 11, and a data line B is connected to a drain D thereof. The source S of the FET 11 is connected to the gate G of the FET 12 as a light emission driving transistor. A drive voltage Vc is applied to the source S of the FET 12 via the anode power supply line 16, and a capacitor 13 is connected between the gate G and the source S. Further, the drain D of the FET 12 has E
The anode end of the L element 15 is connected. EL element 1
A ground potential GND is applied to the cathode terminal of the transistor 5 via a cathode power supply line 17.

[0005] drive 100 sequentially to the scanning lines A 1 to A n each display panel 10, continue to apply an alternative scanning pulse. Further, the driving device 100 synchronizes with the application timing of the scanning pulse to generate pixel data pulses DP 1 to D corresponding to the input video signals corresponding to the respective horizontal scanning lines.
P m are generated and applied to the data lines B 1 -B m respectively. Each of the pixel data pulses DP has a pulse voltage corresponding to the luminance level indicated by the input video signal. At this time, the scanning line A to which the scanning pulse is applied
Each of the EL units connected above is a target of writing pixel data. The FET 11 in the EL unit E to which the pixel data is to be written is turned on in response to the scan pulse, and the pixel data pulse DP supplied via the data line B is transmitted to the gate G of the FET 12 and the capacitor 13. Each is applied. The FET 12 generates a light emission drive current according to the pulse voltage of the pixel data pulse DP, and supplies this to the EL element 15. In response to the light emission drive current, the EL element 15 causes the pixel data pulse D
Light is emitted at a luminance corresponding to the pulse voltage of P. During this time, the capacitor 13 is charged by the pulse voltage of the pixel data pulse DP. By such a charging operation, a voltage corresponding to the luminance level indicated by the input video signal is held in the capacitor 13, and so-called pixel data is written. Here, when the pixel data is released from the writing target of the pixel data, the FET 11 is turned off, and the supply of the pixel data pulse DP to the gate G of the FET 12 is stopped. However, even during this time, the voltage held in the capacitor 13 continues to be applied to the gate G of the FET 12 as described above.

Incidentally, the internal resistance of the EL element 15 may be different for each display panel due to manufacturing variations, and the internal resistance changes in accordance with a change in environmental temperature or a cumulative light emitting time. Therefore, the light emission drive current also changes with the change in the internal resistance of the EL element 15, and this appears as a change in the luminance level during light emission. Therefore,
There has been a problem that the luminance level of the entire screen of the display panel 10 fluctuates due to manufacturing variations, changes in environmental temperature, or the effects of the accumulated light emission time.

Further, each EL in the EL units E 1,1 to En , m
Since the light emission frequency of the element 15 differs depending on the input video signal, the accumulated light emission time also differs. Therefore, when the display panel 10 is driven for a long time, the resistance values of the EL elements 15 vary, and the resulting variation in light emission luminance causes luminance unevenness and burning.

[0008]

SUMMARY OF THE INVENTION The present invention has been made to solve such a problem, and it is an object of the present invention to always maintain the luminance level of the entire screen within a certain range while preventing luminance unevenness in the screen. It is an object of the present invention to provide a driving device and a driving method of a display panel which can perform the above.

[0009]

A display panel driving apparatus according to a first aspect of the present invention drives a display panel in which a plurality of light-emitting elements each carrying a pixel are arranged in a matrix based on an input image signal. A driving voltage generating circuit for supplying a driving voltage to each of the plurality of light emitting elements via a power supply line, and a drive voltage generating circuit for causing each of the light emitting elements to sequentially emit light individually and flowing on the power supply line. Current measuring means for obtaining a current value at the timing of light emission of each of the light emitting elements as a measured current value and storing the measured current value in a memory in association with each pixel; and one of the measured current values is Drive voltage adjusting means for adjusting the voltage value of the drive voltage so as to be equal to a predetermined reference current value.

A display panel driving apparatus according to a second aspect of the present invention is a display panel driving apparatus for driving a display panel, on which a plurality of light emitting elements each of which carry a pixel are arranged in a matrix, based on an input image signal. A drive device, a drive voltage generation circuit that supplies a drive voltage to each of the plurality of light emitting elements via a power supply line, and the current value flowing on the power supply line while sequentially and independently emitting light from each of the light emitting elements, Current measuring means for acquiring a value taken at the timing of light emission of each light emitting element as a measured current value and storing the measured current value in a memory in association with each pixel; one of the measured current values is a predetermined reference current Driving voltage adjusting means for adjusting the voltage value of the driving voltage so as to be equal to a value, and a luminance level indicated by pixel data of each pixel corresponding to the input image signal, Brightness correction means for obtaining brightness corrected pixel data by correcting based on the measured current value stored in the memory in association with one of the pixels corresponding to the raw data, and each frame period in the input image signal And light emission driving means for causing the light emitting element to emit light only during a period corresponding to the luminance correction pixel data in an image display light emission period within the pixel.

Further, according to a first aspect of the present invention, there is provided a display panel driving method for driving a display panel in which a plurality of light-emitting elements each carrying a pixel are arranged in a matrix based on an input image signal. A driving method, in which each of the light-emitting elements emits light individually in sequence, and a current value flowing on a power supply line that supplies a drive voltage to each of the light-emitting elements is taken in at a timing when each of the light-emitting elements emits light. A current measurement step of obtaining a measurement current value corresponding to each pixel; a drive voltage adjustment step of adjusting a voltage value of the drive voltage such that one of the measurement current values is equal to a predetermined reference current value; Having.

Further, according to a second aspect of the present invention, there is provided a display panel driving method for driving a display panel in which a plurality of light emitting elements each carrying a pixel are arranged in a matrix based on an input image signal. A driving method, in which each of the light-emitting elements emits light individually in sequence, and a current value flowing on a power supply line that supplies a drive voltage to each of the light-emitting elements is taken in at a timing when each of the light-emitting elements emits light. A current measurement step of obtaining a measurement current value corresponding to each pixel; a drive voltage adjustment step of adjusting a voltage value of the drive voltage such that one of the measurement current values is equal to a predetermined reference current value; A luminance level indicated by pixel data of each pixel corresponding to the input image signal is stored in the memory in association with one of the pixels corresponding to the pixel data. A brightness correction step of obtaining brightness correction pixel data by correcting based on the measured current value, and the light emitting element only for a period corresponding to the brightness correction pixel data in an image display light emission period in each frame period of the input image signal. And a light emission driving step of emitting light.

[0013]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the present invention will be described in detail with reference to the drawings. FIG. 3 is a diagram showing a configuration of an electroluminescent display device (hereinafter, referred to as an EL display device) for displaying an image by a display panel driving method according to the present invention.

As shown in FIG. 3, the EL display device includes a variable drive voltage generation circuit 1, a current detection circuit 2, a multiplier 3, a drive control circuit 4, a scan line driver 5, a data line driver 6, an operation device 7, It comprises a light emission drive current value memory 8, a non-light emission current value register 9A, a representative current value register 9B, and a display panel 10. Display panel 1
0 is the anode power line 16, the cathode power line 17, 1
A scanning line A 1 that carries each of the n horizontal scanning lines of the screen
To An and m data lines B 1 to B m arranged so as to intersect each scanning line. The drive voltage Vc is applied to the anode power supply line 16, and the cathode power supply line 17 is grounded. In addition, each intersection of the scanning lines A 1 to A n and the data lines B 1 .about.B m in the display panel 10, EL unit E serving as pixels
1,1 to En , m are formed. Note that the internal configuration of the EL unit E is the same as that shown in FIG. 2 as described above, and a description thereof will be omitted.

The variable drive voltage generation circuit 1 generates the DC drive voltage Vc having a voltage value designated by the drive voltage designation signal VD supplied from the drive control circuit 4,
This is applied to the anode power supply line 16 of the display panel 10. The current detection circuit 2 detects a current flowing on the anode power supply line 16 and supplies a current value data signal CD indicating the value of the detected current to the drive control circuit 4. The current detection circuit 2 includes, for example, a variable drive voltage generation circuit 1 as shown in FIG.
And a resistor R1, a measurement switch SW, and an A / D converter AD connected between the anode power supply lines 16 of the display panel 10. The measurement switch SW is turned off while the drive control circuit 4 supplies the logic level 1 current detection enable signal CE, and turned on while the logic level 0 current detection enable signal CE is supplied. To short-circuit both ends of the resistor R1. That is, while the measurement switch SW is in the off state, the current detection circuit 2 is in a current detection operation state, and supplies a voltage generated across the resistor R1 to the A / D converter AD in accordance with the current value. At this time, the A / D converter AD supplies a value obtained by converting the voltage generated at both ends of the resistor R1 to a digital value to the drive control circuit 4 as a current value data signal CD.

The multiplier 3 is sequentially supplied with pixel data PD for each pixel based on an image signal carrying an image to be displayed on the display panel 10. At this time, the pixel data PD indicates a display luminance level for each pixel. The multiplier 3 receives the input pixel data PD for each pixel.
The luminance correction pixel data LD obtained by multiplying the luminance control pixel data LD by the luminance correction value K supplied from the drive control circuit 4 is supplied to the drive control circuit 4. That is, the drive control circuit 4 controls the display panel 10
Each time the pixel data PD corresponding to each of the EL units E1,1 to En , m carrying the pixels is sequentially input, the measured current value for each pixel, which has been measured in advance, is stored in the light emission drive current value memory. 8, a luminance correction value K corresponding to the measured current value is generated and supplied to the multiplier 3. The details of the operation of measuring the measured current value for each pixel and the operation of generating the luminance correction value K will be described later.

The operating device 7 receives various operations by the user and supplies various command signals corresponding to the operations to the drive control circuit 4. For example, the operation device 7 includes the display panel 1
A power-on signal ON is supplied to the drive control circuit 4 in response to a power-on operation performed by a user to start a display operation by 0. On the other hand, the operating device 7 supplies a power-off signal OFF to the drive control circuit 4 in response to a power-off operation performed by the user to stop the display operation. The operation device 7 supplies a luminance correction control signal LAD to the drive control circuit 4 in response to a luminance correction command operation by the user.

The drive control circuit 4 supplies the power-on signal ON
In response to this, while performing the operation of generating the luminance correction value K (described later), the grayscale driving control of the display panel 10 is performed so as to perform the halftone luminance display based on the luminance correction pixel data LD. At this time, various gray scale methods are conceivable for gray scale driving of the display panel 10. Here, a case where the display panel 10 is implemented by a sub-frame method will be described as an example.

In the sub-frame method, a display period of one frame is divided into N sub-frames, and a different light emission period is assigned to each sub-frame. Then, according to the luminance level indicated by the pixel data, by determining a combination of subframes for performing light emission,
The intermediate luminance is expressed at the (2 N +1) stage.
The drive control circuit 4 sends various drive control signals to drive the display panel 10 by the drive using the sub-frame method to the scan line driver 5 and the data line driver 6.
To supply.

The operation of the scanning line driver 5 and the data line driver 6 will be described below, taking as an example the case where the display panel 10 is driven by dividing the display period of one frame into three sub-frames SF1 to SF3 as shown in FIG. Will be described. Scan line driver 5, the subframe SF1~SF3 in each as shown in FIG. 5, sequential scan lines A 1 to A n each display panel 10, continue to apply an alternative scanning pulse. During this time, the data line driver 6 applies the pixel data pulses DP 1 to DP m corresponding to each of the m pieces of luminance correction pixel data LD corresponding to each of the m pixels existing on each scan line to the scan pulse application timing. In synchronization with the data lines B 1 to B m . It should be noted that the pixel data pulse DP is generated within the subframe by EL
The unit E has a pulse voltage of a high voltage when emitting light, and a low voltage (for example, 0 volt) when not emitting light. At this time, the EL unit E connected to the scan line A to which the scan pulse is applied becomes a target of writing pixel data.
The FET 11 in the EL unit E to which the pixel data is to be written is turned on in response to the scan pulse, and the pixel data pulse DP supplied via the data line B is supplied to the gate G of the FET 12 and the capacitor 13.
Respectively. The FET 12 controls the light emission drive current (EL element 1) according to the pulse voltage of the pixel data pulse DP.
Current determined by the impedance of 5)
This is supplied to the EL element 15. That is, EL element 1
5 is a light emitting state by the light emitting drive current when the high voltage pixel data pulse DP is supplied. on the other hand,
When a low-voltage pixel data pulse DP is supplied, a non-light emitting state is set. At this time, when a high-voltage pixel data pulse DP is supplied to the EL element 15 in the subframe SF1 as shown in FIG.
The light emission is continued for a period of "1". When a high-voltage pixel data pulse DP is supplied to the EL element 15 in the sub-frame SF2, the EL element 15
Causes light emission to continue for a period of "2". When a high-voltage pixel data pulse DP is supplied to the EL element 15 in the sub-frame SF3, the EL element 1
5 continues light emission over a period of "4".

Therefore, for example, the sub-frames SF1 to SF
When light emission is performed only in SF3 of No. 3, light emission is performed only in the period of "4" in one frame display period.
The luminance corresponding to the light emission period “4” is visually recognized by human eyes.
When light emission is performed in the sub-frames SF1 and SF3, “1” + “4” = “within one frame display period”.
Since the light emission is performed only during the period of 5 ", the human eye can see the luminance corresponding to the light emission period of" 5 ". Similarly, when the light emission is performed in the sub-frames SF2 and SF3, 1 is obtained.
Since light emission is performed only during the period of “2” + “4” = “6” in the frame display period, the luminance corresponding to the light emission period “6” is visually recognized by human eyes.

As described above, when the display panel 10 is driven by using the three sub-frames as shown in FIG. 5, it is possible to express an intermediate luminance of eight gradations by combining the sub-frames that emit light. It becomes. On the other hand, the drive control circuit 4 executes a light emission drive current measurement routine as shown in FIG. 6 according to the power-off signal OFF.

In FIG. 6, first, the drive control circuit 4
All of the EL units E 1, 1 to E n, and supplies a drive control signal to allowed to off state FET12 on each scan line driver 5 and a data line driver 6 in the m (step S1). Next, the drive control circuit 4 sets the logic level 1
Is supplied to the current detection circuit 2 (step S2). Thereby, the current detection circuit 2
A voltage generated at both ends of the resistor R <b> 1 is detected according to a current flowing on the anode power supply line 16, and a current value data signal CD having the detected voltage value is supplied to the drive control circuit 4.
That is, when the operations of all the EL units E 1,1 to En , m are stopped, the current flowing on the anode power supply line 16 is detected. Next, the drive control circuit 4 stores the current value indicated by the current value data signal CD in the non-light-emission current value register 9A as a non-light-emission current value flowing during the non-display operation by the display panel 10 (step S3). . Next, the drive control circuit 4 sets the row number register X
(Not shown) stores "1" as an initial row number, and stores "1" as an initial column number in a column number register Y (not shown) (step S4). Next, the drive control circuit 4 corresponds to the row number stored in the row number register X and the column number stored in the column number register Y among the EL units E 1,1 to En , m . A drive control signal for driving only the EL units EX and Y to emit light is supplied to each of the scanning line driver 5 and the data line driver 6 (step S5). By the execution of step S5, the scan line driver 5, among the scanning lines A 1 to A n, a scan pulse is applied only to the scanning line A X indicated by the line number stored in the row number register X. At the same time, the data line driver 6 sets the data lines B 1 to B m
Among them, a high voltage is applied only to the data line BY indicated by the column number stored in the column number register Y, and a low voltage pixel data pulse DP is applied to the other data lines B. By the operation as described above, the EL units E 1,1 to E
E of n and m formed in EL unit EX and Y
A light emission drive current flows only through the L element 15 and this EL element 1
5 emits light. Therefore, only the light emission drive current consumed by the EL elements 15 in the EL units EX and Y flows on the anode power supply line 16. At this time, the current detection circuit 2 supplies a current value data signal CD indicating the value of the current flowing on the anode power supply line 16 to the drive control circuit 4.

Here, the drive control circuit 4 takes in the current value indicated by the current value data signal CD and uses it as a measured current value in the address of the light emission drive current value memory 8.
[X, Y] is stored (step S6). Next, the drive control circuit 4 increments the column number stored in the column number register Y by 1 (step S7). Next, the drive control circuit 4 determines whether or not the column number stored in the column number register Y is larger than the last column number m.
(Step S8). If it is determined in step S8 that the column number stored in the column number register Y is not larger than the final column number m, the drive control circuit 4
Returning to the execution of step S5, the operation as described above is repeatedly executed.

For the repetitive execution of steps S5 to S8
According to the row number stored in the row number register X,
Scan line A shownXEL unit E on topX, 1
~ E X,mFlow into the EL elements 15 formed in each
The light emission drive current is measured sequentially and individually, and the light emission drive current value
It is stored in the memory 8. On the other hand, step S
8, the column number stored in the column number register Y
Is determined to be greater than the last column number m,
The operation control circuit 4 determines whether the row stored in the row number register X
The number is incremented by 1 and written to the column number register Y.
The stored column number is rewritten to 1 (step S9).
That is, by performing the step S9, the light emission drive is performed.
An EL unit group E to be measured is formed.
Scan line AXTo the next scan line AX + 1Migrate to
It is. Here, the drive control circuit 4 operates in a row number register
If the line number stored in X is larger than the last line number n,
It is determined whether or not there is (step S10). Such a stage
In step S10, the data stored in the row number register X is stored.
Line number is not greater than the last line number n
In this case, the drive control circuit 4 executes the above-described step S5.
Return The operation as described above is repeatedly executed.

According to the repetition of steps S5 to S10, all the ELs formed on the display panel 10 are
The emission drive current is individually measured for the EL elements 15 in each of the units E1,1 to En , m , and the measurement results are stored in the emission drive current value memory 8 in association with each pixel. is there. If it is determined in step S10 that the row number stored in the row number register X is larger than the last row number n, the drive control circuit 4 stores the data in the light emission drive current value memory 8. The smallest current value is searched for among the measured current values for each pixel, and the current value is stored in the representative current register 9B as a representative current value I REF (step S11). Next, the drive control circuit 4 sends the current detection enable signal CE of logic level 0 to the current detection circuit 2.
(Step S12). As a result, both ends of the resistor R1 provided in the current detection circuit 2 are short-circuited, so that the drive voltage Vc generated by the variable drive voltage generation circuit 1 is directly applied to the anode power supply line 16. After the execution of step S12, the drive control circuit 4 exits the light emission drive current measurement routine and returns to the execution of the main routine (not shown).

At this time, the light emission drive current measurement routine is executed in response to the power-off operation performed by the user to stop the display operation on the display panel 10 as described above. That is, during the period when the display operation based on the image data is not performed, the EL element 1
The light emission drive current flowing when the light emitting element 5 emits light alone is measured, and the measurement result is stored in the light emission drive current value memory 8 as a measured current value.

After the execution of the light emission drive current measurement routine, the drive control circuit 4 proceeds to the execution of a drive voltage setting routine as shown in FIG. 7, first, the drive control circuit 4 determines whether or not the representative current value I REF stored in the representative current value register 9B is smaller than a predetermined upper limit current value I MAX (step S1). S31). Note that the upper limit current value IMAX is an upper limit value of a light emission drive current for causing the EL element 15 to emit light to such an extent that power consumption does not exceed a predetermined value while securing minimum luminance. Step S3 above
1, when it is determined that the representative current value I REF is not smaller than the upper limit current value I MAX , the drive control circuit 4 changes the voltage value designated by the drive voltage designation signal VD to a predetermined voltage value immediately before. The drive voltage specifying signal VD having the voltage value obtained by subtracting α as a new specified voltage value is supplied to the variable drive voltage generating circuit 1 (step S32). By executing step S32, the variable drive voltage generation circuit 1 applies the drive voltage Vc whose voltage value has been reduced by the predetermined voltage value α to the anode power supply line 1.
6 Next, the drive control circuit 4 executes the light emission drive current measurement routine as shown in FIG. 6 again (step S33). That is, the drive voltage V applied to the anode power supply line 16 by the predetermined voltage value α in step S32
In a state where c has been reduced, the EL unit E 1,1
That is, the emission drive current is individually measured for the EL elements 15 in each of .about.E n, m . After the execution of step S33, the drive control circuit 4 returns to the execution of step S31 and repeatedly executes the above-described operation. That is,
The drive control circuit 4 determines that the representative current value I REF is equal to the upper limit current value I MAX
The drive voltage Vc to be applied to the anode power supply line 16 is reduced by a predetermined voltage value α until the power supply voltage Vc becomes smaller.

Here, if it is determined in step S31 that the representative current value I REF is smaller than the upper limit current value I MAX , the drive control circuit 4 then proceeds to step S 31.
It is determined whether or not REF is larger than a predetermined lower limit current value I MIN (step S34). Note that the lower limit current value I MIN is a lower limit value of a light emission drive current for causing the EL element 15 to emit light with the minimum necessary luminance. When it is determined in step S34 that the representative current value I REF is not larger than the lower limit current value I MIN , the drive control circuit 4 determines a predetermined value from the voltage value designated by the drive voltage designation signal VD until immediately before. A drive voltage specifying signal VD having a voltage value obtained by adding the voltage value α as a new specified voltage value is supplied to the variable drive voltage generation circuit 1.
(Step S35). By performing step S35, the variable drive voltage generation circuit 1 supplies the drive voltage Vc whose voltage value has been increased by the predetermined voltage value α to the anode power supply line 16. After the execution of step S35, the drive control circuit 4
Shifts to the execution of the light emission drive current measurement routine in step S33. That is, in a state where the drive voltage Vc applied to the anode power supply line 16 is increased by the predetermined voltage value α in the above step S35, the EL element 15 in each of the EL units E1,1 to En , m is again applied. Thus, the light emission drive current is individually measured. Step S above
After the execution of step S33, the drive control circuit 4 proceeds to step S31.
And the above-described operation is repeatedly executed.
That is, the drive control circuit 4 operates until the representative current value I REF becomes larger than the lower limit current value I MIN until the representative power supply line 16
Is increased by a predetermined voltage value α.

[0030] Here, in step S34, the representative current value I when the REF is determined to be larger than the lower limit current value I MIN is the representative current value I REF is lower current value I
It means that in the range of MIN ~ upper limit current value I MAX,
The drive control circuit 4 exits the drive voltage setting routine and returns to the execution of the main routine (not shown). As described above, according to the execution of the drive voltage setting routine, the EL unit E
The light emission drive current value which is the smallest among the light emission drive currents flowing through the respective EL elements 15 of 1, 1 to En , m is the light emission drive current required when the EL element 15 emits light within a desired luminance range. The drive voltage Vc is adjusted so as to have a value.

Therefore, even if the internal resistance value of the EL element 15 fluctuates due to manufacturing variations, changes in environmental temperature, accumulated light emission time, or the like, the luminance level of the entire screen of the display panel 10 is always set to a desired level. It can be maintained within the luminance range. Here, when the user performs a power-on operation using the operation device 7 in order to start the display operation by the display panel 10, the operation device 7 turns on the power-on signal.
Is supplied to the drive control circuit 4. Such power-on signal ON
The drive control circuit 4 responds to the input pixel data P
In order to generate the brightness correction value K corresponding to D, a brightness correction value generation routine as shown in FIG. 8 is executed.

In FIG. 8, first, the drive control circuit 4
The determination as to whether or not the pixel data PD has been input is repeatedly performed until the input of the pixel data PD is performed (step S21). If it is determined in step S21 that the pixel data PD has been input, the drive control circuit 4
Reads the measured current value corresponding to the pixel corresponding to the input pixel data PD from the light emission drive current value memory 8
(Step S22). Next, the drive control circuit 4 obtains a division result obtained by dividing the representative current value I REF stored in the representative current value register 9B by the measured current value as a luminance correction value K (step S23). 3 (step S24). Therefore, the multiplier 3 generates luminance correction pixel data LD having a value represented by the following equation for each pixel.

LD = Pixel Data PD / Brightness Correction Value K = Pixel Data PD · (Representative Current Value I REF / Measured Current Value) Next, the drive control circuit 4 checks whether the power-off signal OFF is supplied from the operation device 7. (Step S2)
5). In step S25, the power-off signal OF
When it is determined that F is not supplied, the drive control circuit 4 returns to the execution of step S21 and repeatedly executes the above-described operation. On the other hand, if it is determined in step S25 that the power-off signal OFF has been supplied,
The drive control circuit 4 exits the brightness correction value generation routine and proceeds to the execution of a light emission drive current measurement routine as shown in FIG.

According to the execution of the brightness correction value generation routine, as the light emission drive current measured for each pixel becomes larger than the representative current value I REF , the EL corresponding to the pixel becomes larger.
A luminance correction value K is generated in which the period during which the EL element 15 in the unit E should emit light is shorter than the period indicated by the pixel data PD. Then, a value obtained by multiplying the pixel data PD supplied corresponding to the pixel by the luminance correction value K is obtained as the luminance correction pixel data LD.

For example, the measured current value of the EL element 15 formed in the EL unit E 1,1 is equal to the representative current value I REF.
Is 120%, the luminance correction value K is 0.83, and the value obtained by multiplying the pixel data PD supplied corresponding to the EL unit E 1,1 by 0.83 is the luminance correction pixel data LD. It becomes. Further, the measured current value of the EL element 15 formed in the EL units E 1 and E 2 is one of the representative current values described above.
When it is 10%, the luminance correction value K becomes 0.91,
The pixel data PD supplied corresponding to the EL units E 1 and E 2 is multiplied by 0.91 to obtain the luminance correction pixel data LD.

That is, the EL element 15 having a small emission drive current is compared with the EL element 15 having a large emission drive current.
The luminance correction is performed on the pixel data PD so that the light emission period in each frame is shorter than that of the pixel data PD. That is, the EL element 15 having a large light emission drive current has a higher luminance during light emission than the EL element 15 having a small light emission drive current, but corresponds to the EL element 15 having a large light emission drive current. The apparent luminance on the screen is made uniform by shortening the light emission period per frame by the pixel data PD.

Accordingly, even if the emission luminance of each EL element corresponding to each pixel varies because the display panel 10 is driven for a long time, it is possible to provide a high quality image display without luminance unevenness. It becomes. In the above embodiment, the smallest current value among the measured current values for each pixel stored in the light emission drive current value memory 8 is set as the representative current value I REF , but the largest current value is set as the representative current value I REF. Representative current value I
It may be REF . At this time, the drive control circuit 4 searches for the largest current value among the measured current values for each pixel stored in the light emission drive current value memory 8 in step S11 shown in FIG. The current value is represented by the representative current value I
REF is stored in the representative current value register 9B. Accordingly, with respect to the EL element 15 having the largest emission drive current, the pixel data PD is set such that the EL element 15 having the smallest emission drive current has a longer emission period in one frame.
Is corrected. At this time, the brightness correction value K is always larger than 1. Therefore, when obtaining the luminance correction pixel data LD by multiplying the input pixel data PD by the luminance correction value K, multiplication by a predetermined coefficient (less than 1) is further performed. For example, assuming that the predetermined coefficient is 0.7, LD = pixel data PD · 0.7 · luminance correction value K = pixel data PD · 0.7 (representative current value I REF / measured current value). LD is obtained.

In the above embodiment, the value of the light emission drive current actually measured for each pixel is stored in the light emission drive current value memory 8 as a measured current value. The difference from the representative current value I REF may be stored in the light emission drive current value memory 8 in association with each pixel. In addition, there may be a small amount of current consumed inside the display panel 10 in addition to the light emission drive current flowing into the EL element 15 itself. Therefore, in order to accurately measure the emission drive current flowing into the EL element 15 itself, a value obtained by subtracting the non-emission current value stored in the non-emission current value register 9A from the current value detected by the current detection circuit 2 is used. Light emission drive current value memory 8 as the final measured current value
May be stored.

When each of the measured current values obtained by individually measuring the light emission drive current flowing for each pixel is a current value outside a predetermined specified current value range, the drive control circuit 4
It is also possible to determine that the EL unit E carrying the pixel corresponding to the measured current value has failed, and supply "0" to the multiplier 3 as the luminance correction value K corresponding to the pixel.
At this time, since the pixel data PD is multiplied by 0, the luminance correction pixel data LD becomes 0, and the EL element 15 corresponding to the pixel is always turned off. That is, the drive control circuit 4 forcibly prohibits the light emitting operation for the EL unit E corresponding to the failed pixel.

Further, in the above embodiment, the light emission drive current measurement routine as shown in FIG. 6 is executed only once in response to the power-off operation by the user, but this is repeatedly executed periodically. You may do it. Further, the timing for starting the execution of the light emission drive current measurement routine is not limited to the power-off operation by the user. For example, when the EL display device itself shown in FIG. 3 is mounted as a display device of various portable information terminal devices such as a mobile phone, the charging operation of the portable information terminal device or the display on the display panel 10 is performed. The light emission drive current measurement routine may be executed when the surface is closed. Further, it may be forcibly executed in response to a luminance correction command operation by a user. On this occasion,
When the operating device 7 supplies the brightness correction control signal LAD to the drive control circuit 4 in response to the brightness correction command device, the drive control circuit 4 executes the light emission drive current measurement routine shown in FIG. Is performed. As shown in FIG. 9, in each frame, a light emission drive current measurement period HT is provided in addition to the sub-frames SF1 to SF3 as described above.
The above-mentioned light emission drive current measurement routine may be executed within the routine. That is, the light emission drive current of each pixel is measured by executing the light emission drive current measurement routine in a period other than the image display light emission period including the sub-frames SF1 to SF3 in each frame.

Further, in the above embodiment, the current detection circuit 2 for actually detecting the light emission drive current is provided between the variable drive voltage generation circuit 1 and the anode power supply line 16, but a plurality of variable drive voltage generation circuits 1 are provided. In this case, a current detection circuit may be provided for each variable drive voltage generation circuit. For example, in FIG. 10, a red light emission drive voltage generation circuit 1R, a green light emission drive voltage generation circuit 1G, and a blue light emission drive voltage generation circuit 1B are independently provided as the variable drive voltage generation circuits 1. The red light emission drive voltage generation circuit 1R
EL units E1,1 to EL formed on the display panel 10
A driving voltage is supplied to each of the EL units E that emit red light out of En , m via the anode power supply line 16R. or,
The green light emission drive voltage generation circuit 1G includes an anode power supply line 16G for each of the EL units E that emit green light among the EL units E1,1 to En , m formed on the display panel 10.
A drive voltage is supplied via the. Further, the blue light emission drive voltage generation circuit 1B is connected to each of the EL units E responsible for blue light emission among the EL units E 1,1 to En , m formed on the display panel 10 via the anode power supply line 16B. Supply drive voltage. At this time, the current detection circuit 2R is between the red light emission drive voltage generation circuit 1R and the anode power supply line 16R, the current detection circuit 2G is between the green light emission drive voltage generation circuit 1G and the anode power supply line 16G, the blue light emission drive voltage generation circuit 1B and the anode The current detection circuits 2B are provided between the power supply lines 16B, and the currents are individually detected.

In FIG. 11, the variable drive voltage generating circuit 1 includes a first area display drive voltage generating circuit 1a,
And the second region display drive voltage generating circuit 1b are provided independently of each other. First region display drive voltage generation circuit 1
“a” supplies a drive voltage via the anode power supply line 16a to each of the EL units E responsible for displaying an image in the first screen area GM1 in the screen of the display panel 10. The second area display drive voltage generating circuit 1b is an EL unit E for displaying an image in the second screen area GM2 in the screen of the display panel 10.
A drive voltage is supplied to each of them via the anode power supply line 16b. At this time, the current detection circuit 2a, the second region display drive voltage generation circuit 1b, and the anode power supply line 16b are provided between the first region display drive voltage generation circuit 1a and the anode power supply line 16a.
The current detection circuits 2b are provided between them, and the currents are individually detected. Here, one panel is divided into two regions, but it is needless to say that the number is not limited to two and the number of divisions can be arbitrarily set.

In the above embodiment, the drive voltage setting routine as shown in FIG. 7 is executed after the light emission drive current measurement routine as shown in FIG. 6, but this routine is repeatedly executed. You may do it. or,
In the driving voltage setting routine, the EL units E1,1 to
Adjustment of the drive voltage Vc so that the smallest measured current value among the measured currents measured from each of the EL elements 15 of En and m falls within a predetermined range of the lower limit current value I MIN to the upper limit current value I MAX. It is carried out. However, the lower limit average value of a predetermined in these measured current value of each current value I MI N ~ upper limit current value I MAX
The drive voltage Vc may be adjusted so as to fall within the range described above. At this time, the drive control circuit 4 obtains an average value of the measured current values for each pixel stored in the light emission drive current value memory 8 and sets this as a representative current value I REF in steps S31 to S31 as shown in FIG. The operation in S35 is executed.
In addition, in the range of the lower limit current value I MIN to the upper limit current value I MAX , in short, in the present invention, the EL units E 1,1 to E
The smallest current value among the measured current values measured from the n and m EL elements 15 or the average value of each of the measured current values is determined by a predetermined reference current value (lower limit current value I MIN to upper limit current value I
MAX ) is adjusted to the drive voltage Vc.

In setting the representative current value I REF , the average value of the light emission drive current measured from the plurality of EL elements 15 having the characteristics of all the EL units E formed on the display panel 10 is calculated. The representative current value I REF may be used. Further, the light emission drive current value measured from the EL element 15 of one specific EL unit formed on the display panel 10 may be used as the representative current value I REF as it is. still,
As one specific EL unit, an EL unit E
EL of one of 1,1, ... , En , m , or EL dedicated to obtain a representative current value I REF as shown in FIG.
The unit EX (the same internal configuration as in FIG. 2) may be used.
At this time, the EL unit EX is connected to the EL units E 1 , 1 to 1 .
E n, as with m through the anode power supply line 16 a drive voltage Vc
Is supplied. In obtaining the light emission drive current value by the EL unit EX as the representative current value I REF , the drive control circuit 4 supplies a current measurement signal to the data line driver 6 and the scan line driver 5. In response to the current measurement signal, the data line driver 6 applies the pixel data pulse DP to the EL unit EX via the data line B EX , and the scan line driver 5 applies the scan pulse to the EL unit EX via the scan line A EX. Apply to unit EX. As a result, a light emission drive current flows through the EL element 15 in the EL unit EX to emit light, and a light emission drive current flows on the anode power supply line 16. At this time, the current detection circuit 2
The light emission drive current flowing on the anode power supply line 16 is detected, and a current value data signal CD indicating the current value is supplied to the drive control circuit 4. Drive control circuit 4, such a current value using the current value indicated by the data signal CD, than it is stored in the representative current value register 9B it as representative current value I REF.

[0045]

As described above, according to the present invention, each of the light-emitting drive current values flowing when the light-emitting elements that carry each pixel emit light independently is measured in association with each pixel. . Then, based on the light emission drive current value associated with the pixel corresponding to the input pixel data, the luminance of the input pixel data is corrected, and one of the measured light emission drive current values is set to a predetermined reference current value. The voltage value of the drive voltage supplied to each light emitting element is adjusted so as to be equal to.

Therefore, according to the present invention, it is possible to always maintain the luminance level of the entire screen within a certain range while preventing luminance unevenness in the screen.

[Brief description of the drawings]

FIG. 1 is a diagram showing a schematic configuration of an active matrix drive type EL display device.

FIG. 2 is a diagram illustrating an example of an internal configuration of an EL unit E that carries each pixel.

FIG. 3 shows an active matrix drive type E according to the present invention.
It is a figure showing composition of an L display device.

FIG. 4 is a diagram illustrating an example of an internal configuration of a current detection circuit 2.

FIG. 5 shows a display period of one frame divided into three sub-frames S;
FIG. 9 is a diagram illustrating an example of a light emission drive format in the case of driving divided into F1 to SF3.

FIG. 6 is a diagram showing a light emission drive current measurement routine executed by the drive control circuit 4.

FIG. 7 is a diagram showing a drive voltage setting routine executed by the drive control circuit 4.

FIG. 8 is a diagram showing a luminance correction value generation routine executed by the drive control circuit 4.

FIG. 9 is a diagram showing a light emission drive format in one frame display period when a light emission drive current measurement period HT is provided.

FIG. 10 is a diagram illustrating an installation example of a current detection circuit 2 when a variable drive voltage generation circuit is provided exclusively for each color.

FIG. 11 is a diagram illustrating an installation example of the current detection circuit 2 when a variable drive voltage generation circuit is provided exclusively for each screen area of the display panel 10.

FIG. 12 shows an EL unit E for obtaining a representative current value I REF.
FIG. 2 is a diagram illustrating an example of a display panel 10 on which X is mounted.

[Description of Signs of Main Parts]

1 Variable drive voltage generation circuit 2 Current detection circuit 3 Multiplier 4 Drive control circuit 8 Light emission drive current value memory 10 Display panel

──────────────────────────────────────────────────の Continued on the front page (51) Int.Cl. 7 Identification symbol FI Theme coat ゛ (Reference) G09G 3/20 642 G09G 3/20 642A 642C 642P H05B 33/14 H05B 33/14 A (72) Inventor Ochi Hideo 6-1-1, Fujimi, Tsurugashima-shi, Saitama Prefecture Pioneer Research Institute (72) Inventor Tsuyoshi Sakamoto 6-1-1, Fujimi, Tsurugashima-shi, Saitama Prefecture F-term in Pioneer Research Institute (reference) 3K007 AB04 AB17 BA06 DB03 GA04 5C080 AA06 BB05 DD03 EE28 FF11 GG12 JJ02 JJ03 JJ07

Claims (44)

[Claims]
1. A display panel driving apparatus for driving a display panel, on which a plurality of light emitting elements for each pixel are arranged in a matrix, based on an input image signal, wherein a power supply line is connected to each of the plurality of light emitting elements. A drive voltage generating circuit that supplies a drive voltage via the device, and measuring the current value flowing through the power supply line at the time of light emission of each of the light emitting elements while sequentially causing each of the light emitting elements to emit light individually Current measuring means for obtaining a current value and storing it in a memory in association with each pixel; and adjusting the voltage value of the drive voltage so that one of the measured current values becomes equal to a predetermined reference current value. A drive device for a display panel, comprising: a drive voltage adjusting unit.
2. The image display device according to claim 1, further comprising: a light emitting display unit that causes the light emitting element to emit light only during a period corresponding to the input image signal within an image display light emitting period in each frame period of the input image signal. Outside the image display emission period, each of the pixels is obtained by taking the current value flowing on the power supply line at the timing of light emission of each of the light emitting elements while causing each of the light emitting elements to emit light individually in sequence, as the measured current value. 2. The display panel driving device according to claim 1, further comprising means for storing the data in a memory in association with the data.
3. The current measuring means captures a current value flowing on the power supply line at a timing when each of the light emitting elements emits light, in accordance with a luminance correction command, while sequentially causing each of the light emitting elements to emit light independently. 2. The display panel driving device according to claim 1, further comprising means for storing the measured value in the memory as the measured current value in association with each of the pixels.
4. The current measuring means includes: a scanning light emission driving means for sequentially and independently emitting light from each of the light emitting elements; a current detection circuit for detecting a current value flowing on the power supply line; Means for taking in the measured current value at the timing of light emission of each of the light emitting elements and storing the measured current value in the memory as the measured current value in association with each of the pixels. The driving device of the display panel according to the above.
5. A current detection circuit comprising: a resistor connected in series to the power supply line; means for extracting a voltage value generated at both ends of the resistor as the current value; A switch that shorts both ends,
The driving device for a display panel according to claim 4, comprising:
6. The non-light-emitting current measurement means for obtaining a value of a current flowing on the power supply line as a non-light-emitting current value when all the light-emitting elements formed on the display panel are turned off. Means, and a light-emitting current measuring means for obtaining, as a light-emitting drive current value, a current value taken at the time of light-emitting of each of the light-emitting elements while a current value flowing on the power supply line while causing each of the light-emitting elements to independently emit light sequentially 2. The display panel driving device according to claim 1, further comprising: means for storing a subtraction result obtained by subtracting the non-light emission current value from the light emission drive current value in the memory as the measurement current value.
7. The driving voltage adjusting means includes means for searching for the smallest current value among the measured current values stored in the memory as a minimum measured current value, and wherein the minimum measured current value is 2. The display panel driving device according to claim 1, further comprising: means for adjusting a voltage value of the driving voltage so that the current value becomes the same as a reference current value.
8. The drive voltage adjusting means adjusts the voltage value of the drive voltage so that the average value of each of the measured current values stored in the memory is the same as the reference current value. 2. The method according to claim 1, further comprising means.
The driving device of the display panel according to the above.
9. The driving voltage adjusting means according to claim 1, wherein said driving voltage adjusting means corresponds to a measured current value corresponding to a predetermined one of said measured current values stored in said memory, or corresponds to a predetermined plurality of said pixels. 2. The display panel driving device according to claim 1, further comprising means for adjusting a voltage value of the driving voltage so that an average value of the measured current values becomes the same current value as the reference current value.
10. A first driving circuit for supplying a driving voltage via a first power supply line to each of the light emitting elements that emit red light among the light emitting elements formed on the display panel. A voltage generating circuit, a second driving voltage generating circuit for supplying a driving voltage via a second power supply line to each of the light emitting elements that emit blue light among the light emitting elements formed on the display panel, and the display. A third power supply voltage is supplied to each of the light emitting elements that emit green light among the light emitting elements formed on the panel through a third power supply line.
A drive voltage generation circuit, wherein the current detection circuit detects a current flowing on the first power supply line, and a second current detection detects a current flowing on the second power supply line 5. The display panel driving device according to claim 4, comprising: a circuit; and a third current detection circuit for detecting a current flowing on the third power supply line.
11. A driving voltage generating circuit, comprising: a first power supply line connected to each of the light emitting elements for displaying an image in at least a first screen area of a screen when the display panel is divided into a plurality of areas. A first driving voltage generating circuit that supplies a driving voltage via the second power supply line to each of the light emitting elements that perform image display in a second screen area different from the first screen area in the screen. A second drive voltage generation circuit for supplying a drive voltage, wherein the current detection circuit detects at least a current flowing on the first power supply line;
5. The display panel driving device according to claim 4, further comprising a second current detection circuit for detecting a current flowing on the power supply line.
12. A display panel driving method for driving a display panel in which a plurality of light emitting elements for each pixel are arranged in a matrix on the basis of an input image signal, wherein each of the light emitting elements emits light individually in turn. A current measurement step of obtaining a measurement current value corresponding to each pixel by capturing a current value flowing on a power supply line for supplying a drive voltage to each of the light emitting elements at a timing when each of the light emitting elements emits light; A drive voltage adjusting step of adjusting a voltage value of the drive voltage so that one of the measured current values becomes equal to a predetermined reference current value.
13. A light emitting display step of causing said light emitting element to emit light only during a period corresponding to said input image signal within an image display light emitting period within each frame period of said input image signal, wherein said current measuring step comprises: Outside the image display light emitting period, the measured current value corresponding to each pixel is obtained by taking in the current value flowing on the power supply line at the timing of light emission of each of the light emitting elements while sequentially emitting the light emitting elements individually and sequentially. 13. The method of driving a display panel according to claim 12, comprising a step of obtaining the following.
14. The current measuring step according to a luminance correction command, sequentially taking each of the light emitting elements individually and taking in a current value flowing on the power supply line at a timing when each of the light emitting elements emits light. 13. The method according to claim 12, further comprising the step of obtaining the measured current value corresponding to each pixel.
15. The non-light-emitting current measurement step includes the step of: obtaining a value of a current flowing on the power supply line as a non-light-emitting current value when all the light-emitting elements formed on the display panel are turned off. A light emission current measurement step of obtaining a current value taken at the timing of light emission of each of the light emitting elements as a light emission drive current value while causing each of the light emitting elements to emit light independently in sequence. 13. The method of driving a display panel according to claim 12, comprising: a step of obtaining, as the measurement current value, a subtraction result obtained by subtracting the non-light emission current value from the light emission drive current value.
16. The driving voltage adjusting step includes a step of searching for a minimum current value among the measured current values as a minimum measured current value, and a step of searching for a current having the same minimum measured current value as the reference current value. 13. The method of driving a display panel according to claim 12, further comprising a step of adjusting a voltage value of the drive voltage so as to obtain a value.
17. The driving voltage adjusting step includes a step of adjusting a voltage value of the driving voltage such that an average value of each of the measured current values becomes the same current value as the reference current value. The method of driving a display panel according to claim 12.
18. The method according to claim 18, wherein the driving voltage adjusting step comprises the steps of: measuring a measured current value corresponding to a predetermined one of the measured current values;
13. The method according to claim 12, further comprising a step of adjusting a voltage value of the drive voltage so that an average value of measured current values corresponding to each of a plurality of predetermined pixels becomes the same current value as the reference current value. The driving method of the display panel described in the above.
19. A display panel driving apparatus for driving a display panel in which a plurality of light-emitting elements for each pixel are arranged in a matrix on the basis of an input image signal, wherein a power supply line is provided for each of the plurality of light-emitting elements. A drive voltage generating circuit that supplies a drive voltage via the device, and measuring the current value flowing through the power supply line at the time of light emission of each of the light emitting elements while sequentially causing each of the light emitting elements to emit light individually Current measuring means for obtaining a current value and storing it in a memory in association with each pixel; and adjusting the voltage value of the drive voltage so that one of the measured current values becomes equal to a predetermined reference current value. A driving voltage adjusting unit, and a luminance level indicated by pixel data of each pixel corresponding to the input image signal, which is previously associated with one of the pixels corresponding to the pixel data. A brightness correction unit that obtains brightness correction pixel data by performing correction based on the measured current value stored in the memory; and corresponds to the brightness correction pixel data in an image display emission period in each frame period of the input image signal. And a light emission driving means for causing the light emitting element to emit light only during a predetermined period.
20. An image display light emission period in each frame period of the input image signal, further comprising light emission display means for causing the light emitting element to emit light for a period corresponding to the input image signal. Outside the image display emission period, each of the pixels is obtained by taking the current value flowing on the power supply line at the timing of light emission of each of the light emitting elements while causing each of the light emitting elements to emit light individually in sequence, as the measured current value. 20. The display panel driving device according to claim 19, further comprising means for storing the data in a memory in association with the data.
21. The current measuring means captures a current value flowing on the power supply line at a timing when each of the light emitting elements emits light, while sequentially emitting the light emitting elements individually in response to a luminance correction command. 20. The display panel driving device according to claim 19, further comprising means for storing in a memory the measured current value as the measured current value in association with each of the pixels.
22. A scanning light emission driving means for sequentially and independently emitting light from each of the light emitting elements, a current detection circuit for detecting a current value flowing on the power supply line, and a current detection means for detecting the current value. 20. A means for storing the measured current value at a timing at which each of the light emitting elements emits light, in association with each of the pixels as the measured current value, and storing the measured current value in the memory. The driving device of the display panel according to the above.
23. A current detection circuit comprising: a resistor connected in series to the power supply line; means for extracting a voltage value generated at both ends of the resistor as the current value; A switch that shorts both ends,
23. The display panel driving device according to claim 22, comprising:
24. A non-light-emitting current measuring means for obtaining a value of a current flowing on the power supply line as a non-light-emitting current value when all the light-emitting elements formed on the display panel are turned off. Means, and a light-emitting current measuring means for obtaining, as a light-emitting drive current value, a current value taken at the time of light-emitting of each of the light-emitting elements while a current value flowing on the power supply line while causing each of the light-emitting elements to independently emit light sequentially. 20. The display panel driving device according to claim 19, further comprising: means for storing a subtraction result obtained by subtracting the non-light emission current value from the light emission drive current value in the memory as the measurement current value.
25. A brightness correction value calculating means for obtaining a brightness correction value from the measured current value associated with one of the pixels corresponding to the pixel data, the brightness correction means comprising: A multiplier that obtains a multiplication result obtained by multiplying the correction value as the luminance correction pixel data,
20. The driving device of a display panel according to claim 19, comprising:
26. The display panel driving device according to claim 25, wherein said brightness correction value calculating means obtains said brightness correction value which decreases as said measured current value increases.
27. The display panel driving device according to claim 25, wherein said luminance correction value calculating means obtains said luminance correction value which increases as said measured current value decreases.
28. The apparatus according to claim 28, further comprising: means for detecting, as a defective pixel, a pixel corresponding to a measured current value out of a predetermined current value range among the measured current values stored in the memory. 20. The display panel driving device according to claim 19, further comprising means for prohibiting a light emitting operation for the light emitting element corresponding to the failed pixel.
29. The drive voltage adjusting means for searching for the smallest current value among the measured current values stored in the memory as a minimum measured current value, and wherein the minimum measured current value is 20. The display panel driving device according to claim 19, further comprising means for adjusting a voltage value of the driving voltage so as to have the same current value as a reference current value.
30. The drive voltage adjusting means adjusts the voltage value of the drive voltage so that the average value of each of the measured current values stored in the memory is the same as the reference current value. 20. The driving device of a display panel according to claim 19, further comprising: means.
31. The driving voltage adjusting means, wherein the measuring current value corresponding to a predetermined one of the measured current values stored in the memory, or the driving current adjusting means corresponds to a predetermined plurality of the pixels, respectively. 20. The apparatus according to claim 19, further comprising means for adjusting a voltage value of the drive voltage so that an average value of the measured current values becomes the same current value as the reference current value.
The driving device of the display panel according to the above.
32. A first driving circuit for supplying a driving voltage via a first power supply line to each of the light emitting elements that emit red light among the light emitting elements formed on the display panel. A voltage generating circuit, a second driving voltage generating circuit for supplying a driving voltage via a second power supply line to each of the light emitting elements that emit blue light among the light emitting elements formed on the display panel, and the display. A third power supply voltage is supplied to each of the light emitting elements that emit green light among the light emitting elements formed on the panel through a third power supply line.
A drive voltage generation circuit, wherein the current detection circuit detects a current flowing on the first power supply line, and a second current detection detects a current flowing on the second power supply line 23. The display panel driving device according to claim 22, comprising: a circuit; and a third current detection circuit for detecting a current flowing on the third power supply line.
33. A first drive circuit for supplying a drive voltage via a first power supply line to each of the light emitting elements responsible for displaying an image in a first screen area of a screen by the display panel. A voltage generation circuit;
A second drive voltage generation circuit that supplies a drive voltage via a second power supply line to each of the light emitting elements that performs image display in a second screen area different from the screen area, wherein the current detection circuit includes: 23. The device according to claim 22, comprising: a first current detection circuit for detecting a current flowing on the first power supply line; and a second current detection circuit for detecting a current flowing on the second power supply line. Display panel driving device.
34. A display panel driving method for driving a display panel in which a plurality of light-emitting elements for each pixel are arranged in a matrix on the basis of an input image signal, wherein each of the light-emitting elements sequentially emits light independently. A current measurement step of obtaining a measurement current value corresponding to each pixel by capturing a current value flowing on a power supply line for supplying a drive voltage to each of the light emitting elements at a timing when each of the light emitting elements emits light; A drive voltage adjusting step of adjusting the voltage value of the drive voltage so that one of the measured current values becomes equal to a predetermined reference current value; And correcting the brightness level based on the measured current value stored in the memory in association with one of the pixels corresponding to the pixel data. A luminance correction step of obtaining data, and a light emission drive step of causing the light emitting element to emit light only during a period corresponding to the luminance correction pixel data in an image display light emission period in each frame period of the input image signal. Driving method of the display panel.
35. The image display apparatus according to claim 35, further comprising: a light emitting display step of causing said light emitting element to emit light only during a period corresponding to said input image signal in an image display light emitting period in each frame period of said input image signal. Outside the image display light emission period, the measurement current corresponding to each of the pixels is obtained by taking in the current value flowing on the power supply line at the timing of light emission of each of the light emission elements while sequentially causing each of the light emission elements to emit light independently. The method for driving a display panel according to claim 34, further comprising a step of obtaining a value.
36. In the current measuring step, a current value flowing on the power supply line is taken in at a timing when each of the light emitting elements emits light, while the light emitting elements are sequentially and individually emitted in response to a luminance correction command. 35. The display panel driving method according to claim 34, further comprising a step of obtaining the measured current value corresponding to each of the pixels.
37. The non-light-emission current measurement step includes the step of: obtaining a value of a current flowing on the power supply line as a non-light-emission current value when all the light-emitting elements formed on the display panel are turned off. A light emission current measurement step of obtaining a current value taken at the timing of light emission of each of the light emitting elements as a light emission drive current value while causing each of the light emitting elements to emit light independently in sequence. 35. The display panel driving method according to claim 34, further comprising: storing a result of subtracting the non-light-emitting current value from the light-emitting drive current value as the measured current value in the memory.
38. A brightness correction value calculating step for obtaining a brightness correction value from the measured current value associated with one of the pixels corresponding to the pixel data, the brightness correction step comprising: A multiplier that obtains a multiplication result obtained by multiplying the correction value as the luminance correction pixel data,
35. The method of driving a display panel according to claim 34, comprising:
39. The display panel driving method according to claim 38, wherein said luminance correction value calculation step obtains said luminance correction value which decreases as said measured current value increases.
40. The display panel driving method according to claim 38, wherein said brightness correction value calculating step obtains said brightness correction value which increases as said measured current value decreases.
41. A method for detecting, as a defective pixel, a pixel corresponding to a measured current value out of a predetermined current value range in each of the measured current values, wherein the light emission driving step includes the step of detecting the light emission corresponding to the failed pixel. The method for driving a display panel according to claim 34, further comprising a step of inhibiting a light emitting operation of the element.
42. The driving voltage adjusting step includes a step of searching for a smallest current value among the measured current values as a minimum measured current value, and a step of searching for a current having the same minimum measured current value as the reference current value. 35. The method for driving a display panel according to claim 34, further comprising a step of adjusting a voltage value of the driving voltage so as to obtain a value.
43. The driving voltage adjusting step includes a step of adjusting a voltage value of the driving voltage such that an average value of each of the measured current values becomes the same current value as the reference current value. 35. The method of driving a display panel according to claim 34.
44. The driving voltage adjusting step, wherein the measuring current value corresponding to a predetermined one of the measured current values stored in the memory, or the measuring current value corresponding to a predetermined plurality of pixels, respectively. 35. The method according to claim 34, further comprising the step of adjusting the voltage value of the drive voltage so that the average value of the measured current values becomes the same current value as the reference current value.
The driving method of the display panel described in the above.
JP2001401815A 2001-12-28 2001-12-28 Device and method for driving display panel Pending JP2003202837A (en)

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US10/322,776 US7274363B2 (en) 2001-12-28 2002-12-19 Panel display driving device and driving method
CN 02828406 CN1703731B (en) 2001-12-28 2002-12-20 Panel display driving device and driving method
EP02806068.9A EP1459285B1 (en) 2001-12-28 2002-12-20 Panel display driving device and driving method
PCT/JP2002/013374 WO2003058594A1 (en) 2001-12-28 2002-12-20 Panel display driving device and driving method
AU2002356439A AU2002356439A1 (en) 2001-12-28 2002-12-20 Panel display driving device and driving method
TW91137196A TW575859B (en) 2001-12-28 2002-12-24 Panel display driving device and driving method

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