JP2001042825A - Driving device of multicolor light emitting display panel - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve the rising characteristics of light emitting of capacitive light emitting elements having different light emitting colors by adjusting the driving current in accordance with luminance data obtained by the operation of a hue adjusting input means and adjusting the levels of second and third potentials so that the level of the third potential comes within an allowable range. SOLUTION: The driving current is adjusted in accordance with the luminance data obtained by the operation of a hue adjustment input means and the levels of second and third potentials are adjusted so that the level of the third potential becomes within an allowable range. In the display device, a light emitting control circuit 12 reads the luminance data of red, green and blue colors outputted from a hue data input section 19, driving currents corresponding to each luminance data are set by retrieving a data table and both end voltages of an organic electroluminescence element are set by retrieving the data table. Moreover, the circuit 12 judges whether each offset voltage, that is computed by using the reverse bias voltage stored in a memory 20, is within an allowable range or not.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a driving apparatus for a multicolor light emitting display panel using a capacitive light emitting element such as an organic electroluminescence element.

[0002]

2. Description of the Related Art In recent years, as display devices have become larger, thinner display devices have been required, and various thin display devices have been put into practical use. An electroluminescent display device configured by arranging a plurality of organic electroluminescent elements in a matrix has attracted attention as one of such thin display devices.

[0003] As shown in FIG. 1, an organic electroluminescent element is formed on a transparent substrate 100 such as a glass plate on which a transparent electrode 101 is formed. Organic functional layer 10
2 and the metal electrode 103 are stacked. The organic functional layer 102 emits light when a positive voltage is applied to the anode of the transparent electrode 101 and a negative voltage is applied to the cathode of the metal electrode 103, that is, a direct current is applied between the transparent electrode and the metal electrode. By using an organic compound that can be expected to have good light-emitting properties for the organic functional layer, the electroluminescent display has become practically usable.

An organic electroluminescent element (hereinafter, simply referred to as an EL element) can be electrically represented by an equivalent circuit as shown in FIG. As can be seen from the figure, the EL element can be replaced with a configuration including a capacitance component C and a component E having a diode characteristic coupled in parallel with the capacitance component. Therefore, the EL element is considered to be a capacitive light-emitting element. In the EL element, when a direct-current light emission drive voltage is applied between the electrodes, the charge is accumulated in the capacitance component C. When the voltage exceeds the barrier voltage or the light emission threshold voltage inherent to the element, the electrode (the anode of the diode component E) From the side), a current starts to flow to the organic functional layer serving as the light emitting layer, and light is emitted with an intensity proportional to the current.

The voltage V-current I-luminance L of such an EL element
Is similar to that of a diode, as shown in FIG. 3, the current I is extremely small at a voltage equal to or lower than the light emission threshold voltage Vth, and rapidly increases at a voltage equal to or higher than the light emission threshold voltage Vth. . The current I and the luminance L are almost proportional. When such a EL element applies a drive voltage exceeding the light emission threshold voltage Vth to the EL element, the EL element exhibits light emission luminance in proportion to a current corresponding to the drive voltage. If no drive current flows, the light emission luminance remains equal to zero.

[0006] A light emitting display panel using a plurality of such EL elements.
A simple matrix driving method is known as a driving method of the
Have been. Figure 4 shows a simple matrix of a multicolor light-emitting display panel.
1 shows a structure of an example of a driving device of a flash drive system. Light emitting display
In the case of a cell, n cathode lines (metal electrodes) B₁~ B_nBut
M anode lines (transparent electrodes) A in the horizontal direction_1R, A_1G, A _1B
~ A_mR, A_mG, A_mBAre provided in parallel in the vertical direction.
EL elements E at the intersections (total n × m)_{1R, 1},
E_{1G, 1}, E_{1B, 1}~ E_{mR, n}, E_{mG, n}, E_{mB, n}Is formed
I have. EL element E_{1R, 1}~ E_{mR, n}Emits red light, EL
Element E_{1G, 1}~ E_{mG, n}Emits green light, and the EL element E_{1B, 1}
~ E_{mB, n}Emit blue light. Continuous in each cathode ray
Three EL elements of each of the three primary colors of red, green, and blue (for example,
If E_{1R, 1}, E _{1G, 1}, E_{1B, 1}) To form one pixel. E
L element E_{1R, 1}, E_{1G, 1}, E_{1B, 1}~ E_{mR, n}, E_{mG, n}, E
_{mB, n}Are anode lines arranged in a grid and running vertically
A_1R, A_1G, A _1B~ A_mR, A_mG, A_mBAnd along the horizontal direction
Cathode ray B₁ ~ B_nCorresponding to the intersection position with one end (above
The anode wire side of the diode component E of the equivalent circuit is in contact with the anode wire.
The other end (behind the diode component E of the above equivalent circuit)
(Polar line side) is connected to the cathode line. Cathode rays run
The anode wire is connected to the anode wire drive circuit 2 and
And an anode line reset circuit 3.

The cathode line scanning circuit 1 determines the potential of each cathode line individually.
Cathode ray B specified separately₁ ~ B_nScan switch 5 corresponding to₁
 ~ 5_n, Each of which has a positive potential V serving as a reverse bias voltage.
Any one of cc and earth potential (0V)
To the corresponding cathode ray. Anode wire drive times
The path 2 supplies a drive current to each EL element through each anode line.
Anode wire A to be supplied_1R, A_1G, A_1B~ A_mR, A_mG, A_mBTo
Current source 2_1R, 2_1G, 2 _1B~ 2_mR, 2_mG, 2_mB(Example
For example, constant current source) and drive switch 6_1R, 6_1G, 6 _1B
~ 6_mR, 6_mG, 6_mBAnd the drive switch
It is configured to control the on / off of the flow individually to the anode wire
You. The drive source can be a voltage source such as a constant voltage source.
However, the current-luminance characteristics described above are stable against temperature changes.
Voltage-brightness characteristics change with temperature
The current source (supply current
Power supply circuit that is controlled to have a desired value)
It is common. Current source 2_1R, 2_1G, 2_1B~ 2_mR, 2
_mG, 2_mBOf the supply current of the EL element at the desired instantaneous luminance.
Light emitting state (hereinafter, this state is referred to as a steady light emitting state)
You. ) Is required to maintain the current. Also,
When the EL element is in a light emitting state, the capacity of the EL element described above is
The charge corresponding to the supplied current amount is charged in the amount component C.
Therefore, the voltage between both ends of the EL element is a specified value corresponding to the instantaneous luminance.
Ve (hereinafter, this is referred to as a light emission regulation voltage).

[0008] anode lines reset circuit 3, the shunt switch 7 provided for each anode line _{1R, 7 1G, 7 1B ~7} mR,
7 _mG and 7 _{mB. When the} shunt switch is selected, the anode wire is set to the ground potential. The cathode line scanning circuit 1, anode line drive circuit 2, and anode line reset circuit 3 are connected to a light emission control circuit 4.

The light emission control circuit 4 includes a cathode line scanning circuit 1, an anode line drive circuit 2, and an anode line reset circuit for displaying an image carried by the image data according to image data supplied from an image data generation system (not shown). 3 is controlled.
Emission control circuit 4, to the cathode line scan circuit 1 generates a scanning line selection control signal, ground select one cathode line corresponding to the horizontal scanning period in which the potential of the image data of the cathode lines B ₁ .about.B _n set the other cathode lines performs control for switching the scanning switches 5 ₁ to 5 _n as positive potential Vcc is applied. The positive potential Vcc is connected to the intersection of the driven anode line and the cathode line not selected for scanning.
To prevent the L element from emitting crosstalk light,
It is applied by a constant voltage source connected to the cathode ray, and is set to have a positive potential Vcc = Ve. Since scanning switches 5 ₁ to 5 _n is switched to sequentially ground potential for each horizontal scanning period, the cathode lines are set to the ground potential, and to function as a scan line that allows emitting the EL elements connected to the cathode line Become.

[0010] The anode line drive circuit 2 applies
Light emission control is performed for this. The light emission control circuit 4 stores the image data
Connected to the scanning line according to the pixel color information indicated by
Which EL element is used, at what timing, at what time
Drive control signal indicating whether to emit light
Signal (drive pulse) and supplies it to the anode wire drive circuit 2.
Pay. The anode line drive circuit 2 receives the drive control signal.
Drive switch 6_1R, 6_1G, 6_1B~
6_mR, 6_mG, 6_mBIs turned on and the anode wire A _1R,
A_1G, A_1B~ A_mR, A_mG, A_mBTo the corresponding EL element through
Drive current. This allows the drive current to be supplied
EL element emits light according to the pixel color information.
Will do. The emission luminance of each EL element for one pixel,
In other words, an arbitrary color can be selected depending on the light emission time
can get.

The reset operation of the anode line reset circuit 3 is as follows.
This is performed in response to a reset control signal from the light emission control circuit 4. Anode line reset circuit 3, shunt switch 7 corresponds to the anode lines to be reset indicated by the reset control signal _{1R, 7 1G, 7 1B ~7} mR, 7 mG, 7 turns on one of _mB than it off and I do. Japanese Unexamined Patent Publication No. 9-232074 by the same applicant as the present application discloses a driving method for performing a reset operation for discharging accumulated charges of each EL element arranged in a grid just before switching a scanning line in a simple matrix display panel. (Hereinafter referred to as a reset driving method) is disclosed. This reset driving method hastens the light emission rise of the EL element when the scanning line is switched. FIG. 4 shows a reset driving method of this simple matrix display panel.
This will be described with reference to FIGS.

The operation shown in FIGS.
Is the cathode ray B₁ To scan the EL element E_{1R, 1}, E_{1G, 1}, E
_{1B, 1}After illuminating the cathode ray B_Two Scan to EL element
E_{2R , 2}, E_{2G, 2}, E_{2B, 2}In the case of flashing
It is. Also, to make the explanation easier to understand,
EL elements are indicated by diode symbols and are not lit.
The light emitting element is indicated by a capacitor symbol. Also, the cathode
Line B₁ ~ B_n Is applied to the EL element.
The potential is set equal to the emission regulation voltage Ve.

First, in FIG.₁
Is switched to the ground potential side of 0 (V),
₁ Are being scanned. Other cathode ray B_Two ~ B_n Scan
Switch 5_Two ~ 5_n Positive potential Vcc is applied
You. At the same time, the anode wire A_1R, A_1G, A_1BThe drive
Itch 6_1R, 6_1G, 6_1BCurrent source 2_1R, 2_1G, 2
_1BIs connected. In addition, another anode wire A_2R, A_2G, A
_2B ~ A_mR, A_mG, A_mBHas a shunt switch 7_2R,
7_2G, 7_2B ~ 7_mR, 7_mG, 7_mB0 (V)
Switch to the high potential side. Therefore, in the case of FIG.
L element E_{1R, 1}, E _{1G, 1}, E_{1B, 1}Only the forward voltage is marked
Current source 2_1R, 2_1G, 2_1BDriven like an arrow from
When current flows, the EL element E_{1R, 1}, E_{1G, 1}, E_{1B, 1}only
Will emit light. In this state, Hatchin
Non-luminescent EL element E shown _{2R, 2}, E_{2G, 2}, E
_{2B, 2}~ E_{mR, n}, E_{mG, n}, E_{mB, n}Are as shown
It will be charged to the polarity.

From the light emitting state shown in FIG.
_{2R, 2}, E_{2G, 2}, E_{2B, 2}Move the scanning to the state where the light is emitted
Immediately before the reset, the following reset control is performed. sand
That is, as shown in FIG._1R,
6_1G, 6_1B~ 6_mR, 6_mG, 6 _mBIs released and all
Scanning switch 5₁ ~ 5_n And all shunt switches
7_1R, 7_1G, 7_1B~ 7_mR, 7_mG, 7_mBIs 0 (V)
Switch to the anode potential side_1R, A_1G, A_1B~ A
_mR, A_mG, A_mBAnd cathode ray B₁ ~ B_nIs 0 (V) once
All resets are made equal to the
You. When this all reset is performed, the anode line and the cathode line
Are all at the same potential of 0 (V), so that each EL element is charged.
The charged charge is discharged, and the charge of all EL elements is reduced.
It disappears in an instant.

Thus, the charge of all the EL elements
, And then, as shown in FIG._Two 
Scan switch 5 corresponding to_Two Only switch to 0 (V) side
Oh, cathode ray B_Two Is scanned. At the same time, drive
Switch 6_2R, 6_2G, 6_2BClose the current source 2_2R, 2_2G,
2_2BThe corresponding anode wire A_2R, A_2G, A_2BWhen you connect to
Both are shunt switches 7_1R, 7_1G, 7_1B , 7_3R,
7_3G, 7_3B ~ 7_mR, 7_mG, 7_mBIs turned on and the anode wire A
_1R, A_1G, A_1B , A_3R, A_3G, A_3B ~ A_mR, A_mG, A
_mBTo 0 (V). Therefore, in the case of FIG.
_{2R, 2}, E_{2G, 2}, E_{2B , 2}Only forward voltage is applied to
Current source 2_2R, 2_2G, 2_2BDrive current flows from the
And the EL element E_{2R, 2}, E_{2G, 2}, E_{2B, 2}Only emits light
The Rukoto.

As described above, the light emission control of the reset driving method
The cathode ray B₁ ~ B_n Active one of
Scan mode, which is the period during which
Mode. Scan mode and reset
The cut mode is performed every horizontal scanning period (1H) of the image data.
Done in If reset control is not performed and the state in FIG.
6 directly shifts to the state of FIG.
2_2R, 2_2G, 2_2BDrive current supplied from the EL element
E_{2R, 2}, E_{2G, 2}, E_{2B, 2}Not only flows into the
Element E_{2R, 3}~ E_{2R, n}, E_{2G, 3}~ E_{2G, n}, E_{2B, 3}~ E_{2B, n}
To reverse charge (illustrated in FIG. 4)
EL element E_{2R, 2}, E _{2G, 2}, E_{2B, 2}To
Light emitting state (EL element E_{2R, 2}, E_{2G, 2}, E_{2B, 2}Both
It takes time to set the terminal voltage to the emission specified voltage Ve).
And

However, the reset control described above is performed.
U, cathode ray B_TwoAt the moment when switching to scanning of
Anode wire A_2R, A_2G, A_2BIs about Vcc,
EL element E to be made to emit light_{2R, 2}, E_{2G, 2}, E_{2B, 2}To
Is the current source 2_2R, 2_2G, 2_2BNot only cathode ray B₁,
B_Three~ B_nFrom multiple routes from constant voltage sources connected to
Also, the charging current flows as shown in FIG.
The parasitic capacitance (the above-mentioned capacitance component C) is charged by the
The light reaches the light regulation voltage Ve, and the light emitting state can be entered. That
Later, cathode ray B_TwoWithin the scanning period of
The amount of current supplied from the current source is the specified emission voltage of the EL element.
The amount of current is sufficient to maintain the light emitting state at Ve.
Therefore, the current source 2_2R, 2_2G, 2_2BThe current supplied by
EL element E_{2R , 2}, E_{2G, 2}, E_{2B, 2}Flows only into
Is used for light emission and maintains the light emitting state shown in FIG.
You.

As described above, according to the reset driving method, before shifting to the emission control of the next scanning line, all of the cathode line and the anode line are temporarily set to the ground potential of 0 (V) or the positive potential V.
Since the cc is reset by being connected to the same potential of cc, when switching to the next scanning line, the charging up to the emission specified voltage Ve is accelerated, and the rising of the emission of the EL element to emit light on the switched scanning line. Can be faster.

[0019]

However, in the EL devices for red, green and blue, since the device structures including the light emitting materials are different from each other, the luminance I-voltage V characteristics are often different from each other. It is. Therefore, when all the EL elements forming one pixel emit light and the display of the pixel becomes white, the voltages applied to both ends of each EL element are also different from each other. Is usually different for each EL element. Therefore, as described above, the reverse control applies the reverse bias voltage Vcc to each of the EL elements for red, green, and blue by the reset control, and when the cathode line for the next scan is selected after the reset control, the selected cathode line is displayed. There is a time difference until the voltage between both ends of each EL element to emit light reaches the specified light emission voltage Ve for each of red, green, and blue, and light emission at the specified light emission voltage Ve does not start at the same time. was there.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a driving device for a multicolor light emitting display panel capable of improving the rising characteristics of light emission of each of the capacitive light emitting elements having different emission colors.

[0021]

According to the present invention, a driving apparatus for a multicolor light-emitting display panel scans at a plurality of drive lines and a plurality of scanning lines which intersect each other, and at a plurality of intersections between the drive lines and the scanning lines. It consists of a plurality of capacitive light-emitting elements that are connected between the line and the drive line and have a polarity and are divided into a plurality of types according to emission colors, and the same type of capacitive light-emitting elements are arranged on the same drive line. A driving apparatus for a multicolor light emitting display panel, wherein a scanning period for selecting one scanning line from a plurality of scanning lines and a reset period subsequent thereto are repeatedly set according to a scanning timing of input image data, Control means for designating a current drive line corresponding to a capacitive light emitting element to emit light on one scanning line according to input image data; applying a first potential to one scanning line during a scanning period; Scanning means for applying a second potential higher than the first potential to the scanning lines other than the scanning line and applying the first potential to all the scanning lines during the reset period, and emitting a positive voltage equal to or higher than the light emission threshold voltage during the scanning period. A drive current is supplied to the current drive line in order to apply a forward direction to the capacitive light emitting element to be caused to emit light, and an offset voltage equal to or lower than the light emission threshold voltage is applied to the capacitive light emitting element to be caused to emit light in the next scanning period during the reset period. Drive means for supplying a third potential to the next drive drive line for applying the control signal, operation input means for outputting luminance data indicating a luminance level of each of the luminescent colors in response to an operation input, and light emission in response to the luminance data Setting means for setting each level of the driving current and the voltage between both ends of the capacitive light emitting element of the type corresponding to each color based on predetermined data, and driving to the level set by the setting means First adjusting means for adjusting the current; calculating means for setting a level difference between a current second potential and a voltage between both ends set by the setting means in accordance with the type of the capacitive light emitting element as a third potential; Determining means for determining whether each level of the third potential calculated by the calculating means for each type of capacitive light emitting element is within a predetermined allowable range, and calculating means for each type of capacitive light emitting element When each of the calculated levels of the third potential is within a predetermined allowable range, the third potential is adjusted to that level, and at least one of the calculated levels of the third potential is within the predetermined allowable range. If not, a second adjusting unit that adjusts each level of the second potential and the third potential so that each level of the third potential is within a predetermined allowable range for each emission color;
It is characterized by having.

According to the present invention, the drive current is adjusted in accordance with the luminance data obtained by operating the tint adjustment input means, and the second potential is adjusted so that each level of the third potential falls within a predetermined allowable range. And the level of the third potential is adjusted, so that even when the brightness of the light emission is adjusted such as the hue adjustment, the voltage between both ends of each capacitive light emitting element having a different emission color during the scanning period changes until the desired voltage is reached. Since the applied voltages can be made equal, it is possible to improve the light emission rising characteristics of each of the capacitive light emitting elements having different emission colors.

[0023]

Embodiments of the present invention will be described below in detail with reference to the drawings. FIG. 7 shows a schematic configuration of a display device in which the present invention is applied to a multicolor light emitting display panel using EL elements as capacitive light emitting elements. This display device has a capacitive light emitting display panel 11, a light emission control circuit 12, a cathode line scanning circuit 13, and an anode line drive circuit 14.

The light emitting display panel 11 has a structure as shown in FIG.
The configuration is the same as that shown in FIGS. sand
That is, the anode wire A of the drive wire_1R, A_1G, A_1B~ A_mR, A
_mG, A_mBAnd the cathode line B of the scanning line₁~ B_nMultiple intersection locations
And a plurality of EL elements E_{1R, 1}, E
_{1G, 1}, E_{1B, 1}~ E_{mG, n}, E_{mR, n}, E_{mB, n}Is the anode wire
A _1R, A_1G, A_1B~ A_mR, A_mG, A_mBAnd cathode ray B₁~
B_nBetween the anode line and the cathode line at each of the
It is connected. EL element E_{1R, 1}~ E_{mR, n}Emits red light
None, EL element E_{1G, 1}~ E_{mG, n}Emits green light, EL
Element E_{1B, 1}~ E_{mB, n}Emit blue light. Smell on each cathode ray
Red (R), green (G), blue (B) EL
Element (eg, E_{1R, 1}, E_{1G, 1}, E_{1B, 1}) To form one pixel
To achieve.

A cathode line scanning circuit 13 is connected to the cathode lines B _{1 to} B _n of the display panel 11, and the anode lines A _1R , A _1G , A _1B.
Anode line drive circuit 14 is connected to _.about.AmR , _AmG and _AmB . Cathode line scanning circuit 13 has a cathode line B ₁ .about.B _n scan switch 15 provided corresponding to each ₁ to 15 _n and the variable voltage source 21 ₁ through 21 _n. Scan switch 15
Each of ₁ to 15 _n supplies one of the ground potential and the reverse bias potential Vcc from the variable voltage sources 21 _{1 to} 21 _n to the corresponding cathode line. Variable voltage source 21 _{1 to} 21 _n
Generates a voltage for obtaining the above-mentioned reverse bias potential Vcc, and the level of the generated voltage Vcc is controlled by the light emission control circuit 12. Variable voltage source 21 _{1 to} 21 _n
The positive terminal is connected to one fixed contact of the scanning switches 15 ₁ to 15 _n, the negative terminal is connected to the ground. Since scanning switches 15 ₁ to 15 _n is switched to sequentially ground potential for each horizontal scanning period under the control of the light emission control circuit 12, the cathode line B ₁ .about.B set to ground potential
_n functions as a scanning line that enables the element connected to the cathode line to emit light.

The anode line drive circuit 14 has an anode line A_1R, A
_1G, A_1B~ A_mR, A_mG, A_mBProvided for each
Drive switch 16_1R, 16_1G, 16_1B~ 16_mR, 1
6_mG, 16_mB, Variable current source 17_1R, 17_1G, 17_1B~ 1
7_mR, 17_mG, 17_mBAnd variable voltage source 18_1R, 18_1G,
18_1B~ 18_mR, 18_mG, 18_mBhave. dry
Switch 16_1R~ 16_mREach against the corresponding anode wire
Variable current source 17_1R, 17_1G, 17_1B~ 17_mR, 1
7_mG, 17_mBCurrent from the variable voltage source 18_1R, 18 _1G,
18_1B~ 18_mR, 18_mG, 18_mBPotential from earth and ground
Supply any one of the potentials. Variable voltage source 18_1R~ 18
_mRIs the offset voltage V_RAnd outputs the variable voltage source 18_1G~
18_mGIs the offset voltage V_GAnd outputs the variable voltage source 18
_1B~ 18_mBIs the offset voltage V_BIs output. Variable current
Source 17_1R, 17_1G, 17_1B~ 17_mR, 17_mG, 17_mBeach
Various current values and variable voltage source 18_1R, 18_1G, 18_1B~ 1
8_mR, 18_mG, 18_mBEach voltage value is determined by the light emission control circuit 12.
Is controlled by

The light emission control circuit 12 controls the image represented by the image data.
EL element connected to scanning line according to elementary color information
Which light is emitted at which timing and for how long
Drive control signal (drive pulse
Is generated and supplied to the anode line drive circuit 14. Sun
The polar drive circuit 14 responds to this drive control signal.
And drive switch 16_1R, 16_1G, 16_1B~ 1
6_mR, 16_mG, 16_mBOf the light emission corresponding to the current
Switch to the source side and control the anode line A_1R, A_1G, A_1B~
A _mR, A_mG, A_mBOf the corresponding anode wire (current drive
Drive power to the corresponding element according to the pixel information
Style I_R, I_G, I_BSupply to other anode wires
Supply the ground potential via the drive switch.
You.

The light emission control circuit 12 is connected to a data input unit 19 and a memory 20. The data input unit 19 is operable to adjust the red, green, and blue luminances of the light emitting display panel 11, and the user operates the adjustment levers (not shown) corresponding to the red, green, and blue, respectively. Is output to the light emission control circuit 12, ie, the luminance data of each of red, green and blue.
Control data such as a data table described later is written in the memory 20 in advance.

Light-emitting display panel 1 by light-emission control circuit 12
The light emission control operation 1 will be described with reference to the flowchart of FIG. The light emission control circuit 12 executes a light emission control routine every horizontal scanning period of the supplied pixel data. In the light emission control routine, first, pixel data for one horizontal scanning period is fetched (step S1), and a scanning selection control signal and a drive control signal are generated according to the pixel information indicated by the fetched pixel data for one horizontal scanning period. (Step S2).

The scanning selection control signal is supplied to the cathode line scanning circuit 13. The cathode line scanning circuit 13 sets one of the cathode lines B _{1 to} B _n corresponding to the current horizontal scanning period indicated by the scanning selection control signal to the ground potential to set one of the cathode lines B _{1 to} B _n to the ground potential.
Scanning switches corresponding to the cathode lines (first scanning switch 15 _S of 15 ₁ to 15 _n, Note, S is one of 1 to n) switched to the ground side. 1 scan switch 15 _i of the scanning switches (15 ₁ to 15 _n to the other cathode lines for applying a positive potential Vcc as a reverse bias potential
Switch to ground).

The drive control signal is the anode line drive circuit 1
4 is supplied. The anode wire drive circuit 14 is driven
Anode line A within the current horizontal scanning period indicated by the control signal_1R,
A_1G, A _1B~ A_mR, A_mG, A_mBOut of the light should be driven
Drive switch corresponding to anode line including pixel element
(16_1R, 16_1G, 16_1B~ 16_mR, 16_mG, 16_mBof
Connect one of the drive switches) to the current source (1
7_1R, 17_1G, 17_1B~ 17_mR, 17_mG, 17_mBOut of
Switch to the side corresponding to). Other anode wires are
Source side. This allows, for example, dry
Switch 16_1R, 16_1G, 16_1BIs the current source 17_1R, 1
7_1G, 17_1BCurrent source 17 when switched to_1R
To drive switch 16_1R, Anode wire A_1R,element
E_{1R, S}, Cathode ray B_S, Scanning switch 15_SAnd earth
Drive current I_RFlows and the current source 17_1GFrom Drives
Itch 16_1G, Anode wire A_1G, Element E_{1G, S}, Cathode ray B_S,
Scan switch 15_SAnd the drive current I to ground_GFlow
Current source 17_1BTo drive switch 16_{1 B}, Anode wire
A_1B, Element E_{1B, S}, Cathode ray B_S, Scanning switch 15_S, That
Drive current I to ground_BFlows. Drive current I_R, I
_G, I_BEL element E supplied with_{1R, S}, E_{1G, S}, E
_{1B, S}Will emit light according to the pixel information.
EL element E_{1R , S}, E_{1G, S}, E_{1B, S}Each emission time is pixel
EL elements can be set individually according to color information.
Child E_{1R, S}, E_{1G, S}, E_{1B, S}Pixels of the desired color
Is shown.

After the execution of step S2, the light emission control circuit 12 determines whether a predetermined time has elapsed (step S3). The predetermined time is set corresponding to a predetermined horizontal scanning period. If the predetermined time has elapsed, the light emission control circuit 12 generates a reset signal (Step S4). The reset signal is supplied to the cathode line scanning circuit 13 and the anode line drive circuit 14. Cathode line scan circuit 13, all of the scanning switches 15 ₁ to 15 in response to a reset signal
_Switch the movable contact of _n to the earth-side fixed contact. The reset signal indicates designation of an anode line (next drive line) corresponding to an EL element to be driven to emit light in the next scanning period.
The anode line drive circuit 14 switches the movable contact of the drive switch connected to the anode line corresponding to the EL element to be driven to emit light in the next scanning period to the offset voltage side fixed contact in response to the reset signal. Thus, an offset voltage is applied to the EL element to be driven to emit light in the next scanning period. That is, the offset voltage V _R is applied to the EL element for red emission to be driven to emit light in the next scanning period, the offset voltage V _G is applied to the EL element for green light emission, the EL element for blue light emission Offset voltage V
_B is applied. Thereby, the capacitance component of each EL element to be driven to emit light in the next scanning period is charged.

When the execution of step S4 is completed, the light emission control circuit 12 ends the light emission control routine and waits until the next horizontal scanning period starts. Step S4 is performed until the next horizontal scanning period is started.
Reset operation is continued. When the next horizontal scanning period starts, the operations in steps S1 to S4 are repeated.

The light emission control operation of the light emission control circuit 12 scans the cathode line B ₁ to emit light for the EL elements E _{1R, 1} , E _{1G, 1} , E _{1B, 1} for _one pixel, and then scans the cathode line B ₂ . To the EL elements E _{2R, 2} , E _{2G, 2} , E _{2B, 2} for one pixel.
Will be described with reference to FIGS. 11 to 13. 3 and 5 in FIGS.
As in the case of the above, for the sake of simplicity of description, a light emitting element is indicated by a light emitting diode symbol, and a non-light emitting element is indicated by a capacitor symbol.

First, FIG.₁only
Is switched to the ground potential side of 0 (V), and the cathode line B₁ But
The element to emit light during the scanning period selected for scanning
E_{1R , 1}, E_{1G, 1}, E_{1B, 1}Operation in which the device emits light in a steady state
The state is shown. Other cathode ray B_Two ~ B_n The scanning scan
Itch 15_Two ~ 15_n Positive potential Vcc is applied
You. At the same time, the anode wire A_1R, A_1G, A_1BThe drive
Itch 16_1R, 16_1G, 16_1BVariable current source 17
_1R, 17_1G, 17_1BIs connected. Also other anode
Line A_2R, A_2G, A_2B ~ A_mR, A_mG, A_mBThe dry
Switch 16_{Two R}, 16_2G, 16_2B ~ 16_mR, 1
6_mG, 16_mBSwitch to 0 (V) earth potential side
I have. Therefore, in the case of FIG._{1R, 1}, E
_{1G, 1}, E_{1B, 1}Only forward voltage is applied, variable current
Source 17_1R, 17_1G, 17_1BFrom the drive current I as shown by the arrow.
_R, I_G, I_BFlow into the EL element E_{1R, 1}, E_{1G, 1}, E
_{1B, 1}Only light will be emitted.

In this state, hatching is shown.
Non-luminous EL element E_{2R, 2}, E_{2G , 2}, E_{2B, 2}~
E_{mR, n}, E_{mG, n}, E_{mB, n}Voltage Vcc is applied between both terminals.
And their capacitance components are opposite to the forward direction as shown.
It will be charged with polarity. In addition, a non-luminous EL element
Child E_{1R, 2}, E_{1G, 2}, E_{1B, 2}~ E_{1R, n}, E_{1G, n}, E_{1B, n}of
Our EL element E_{1R, 2}~ E_{1R, n}Wire A to which is connected_1R
Is Ve_RAnd the EL element E_{1R, 2}~ E_{1R, n}Cathode
B_Two~ B_nIs applied with a potential Vcc. Therefore, the EL element
E_{1R, 2}~ E_{1R, n}Voltage Ve in the forward direction_R-Vcc applied
As a result, the capacitance component is charged. EL element E
_{1G, 2}~ E_{1G, n}Wire A to which is connected_1GIs Ve_Gso
Yes, EL element E_{1G, 2}~ E_{1G, n}Cathode B_Two~ B_nHas a potential
Vcc is applied. Therefore, the EL element E_{1G, 2}~ E_{1G, n}To
Is the voltage Ve_G−Vcc = 0 is applied, and the capacitance component is full.
Not charged. EL element E_{1B, 2}~ E_{1B, n}The anode to which is connected
Line A_1BIs Ve_BAnd the EL element E_{1B, 2}~ E_{1B, n}
Cathode B_Two~ B_nIs applied with a potential Vcc. Therefore, E
L element E_{1B, 2}~ E_{1B, n}Has the voltage Vcc-Ve in the opposite direction._BBut
Is applied, and the capacitance component is charged.

From the light emitting state shown in FIG.
E_{2R, 2}, E_{2G, 2}, E_{2B, 2}Scanning shifts to emitting light
Immediately before the reset control in step S4 described above.
Is performed during the reset period. That is, as shown in FIG.
EL element E_{2R, 2}, E _{2G, 2}, E_{2B, 2}Corresponding to
Live switch 16_2R, 16_2G, 16_2BNon-drive
Switch 16_1R, 16_1G, 16_1BAnd 16_3R, 16_3G,
16_3B~ 16_mR, 16 _mG, 16_mBIs switched to the earth potential side.
Can be replaced and all scan switches 15₁~ 15_n 
Switches to the ground potential side, and the anode wire A_1R, A_1G, A_1BPassing
And A_3R, A_3G, A_3B~ A_mR, A_mG, A_mBAnd cathode ray B₁ ~
B_n Are once made equal to the ground potential side of 0 (V). This
Thereby, the EL element E_{1R, 1}~ E_{1R, n}, E_{1G, 1}~ E_{1G, n},
E_{1B, 1}~ E_{1B, n}And E_{3R, 1}, E_{3G, 1}, E_{3B, 1}~ E_{mR, n},
E_{mG, n}, E_{mB, n}Is reset and those EL elements
Since the potential between the anode and the cathode is equal to 0 (V),
Then, the electric charges charged in each EL element are discharged,
All EL elements are not discharged instantaneously
Become. EL element E_{1G, 2}~ E_{1G, n}About anode and cathode
Is the same potential of 0 (V) between the EL elements E_{1R, 1}, E
_{1G, 1}, E_{1B, 1}They are not charged when flashing,
Since there is no stored charge, it is not discharged.

The drive switch 1 is controlled by the reset control.
6 _2R , 16 _2G , 16 _2B are variable current sources 18 _2R , 18 _2G , 1
It is switched to 8 _2B side. Thus, the positive potential V _R is the drive switches 16 _2R of the variable current source 18 _2R and anode line A,
EL elements E _2R for red light emission through the _{2R, 1 ~E 2R,} is applied to the anode of each of _n, the variable current source 18 _2G positive potential V _G is the drive switches 16 _2G, and through the anode line A _2G Applied to _the respective anodes of the EL elements E _{2G, 1 to} E _{2G, n} for emitting green light,
The variable current source 18 _2B positive potential V _B drive switch 16
_2B and an EL element E for emitting blue light through the anode line A _{2B
2B, 1 to} E2B _{, n} are applied to the anode. EL element E _{2R, 1} , E
_{2G, 1, E 2B, 1} ~E 2R, n, E 2G, n, E 2B, since the cathode of the _n each of which is the ground potential via the corresponding scanning switch 15 ₁ to 15 _n, for red light emission EL elements E _{2R, 1 to} E _{2R, n}
An offset voltage V _R is applied between the anode and the cathode, and an offset voltage V _G is applied between the anode and the cathode of the EL elements E _{2G, 1 to} E _{2G, n} for green light emission, light emitting of the EL element E _{2B, 1} ~E _2B, an offset voltage V _B is applied between the anode and the cathode of _n. Here, the offset voltage _{V R, V G, V R} > 0 is the initial value of _{V B (V), V G} = 0
(V), V _B <0 (V), as shown in FIG. 10, the capacitance components of the EL elements E _{2R, 1 to} E _{2R, n} for red emission are charged with the forward polarity, EL element E _{2G, 1 to} E for emitting green light
_{The 2G, n} capacitance component is not charged and the blue light emitting EL element E
The capacitance components of _{2B, 1 to} E2B _{, n} are charged with the polarity opposite to the forward direction.

Thus, all the EL elements E_{1R, 1}, E
_{1G, 1}, E_{1B, 1}~ E_{1R, n}, E_{1G, n}, E _{1B, n}And E_{3R, 1}, E
_{3G, 1}, E_{3B, 1}~ E_{mR, n}, E_{mG, n}, E_{mB, n}The stored charge of
And EL element E_{2R, 1}, E_{2G, 1}, E_{2B, 1}~ E_{2R, n}, E
_{2G, n}, E_{2B, n}The voltage between both ends is offset voltage V_R,
V_G, V_BAnd then the next scan period
As shown in FIG._Two Scan switch corresponding to
H15_TwoOnly the cathode line B is switched to the ground potential side._Two
 Is selected. At the same time, the drive switch
Switch 16_2R, 16_2G, 16_2BSwitches to the variable current source side
And the variable current source 17_2R, 17_2G, 17_2BThe corresponding anode
Line A_2R, A_2G, A_2BConnect to.

As described above, the scanning switch and the drive switch
The moment the switch is switched, i.e. the scan switch and
The drive switch is switched as shown in FIG.
The state of charge of the parasitic capacitance of each EL element is as shown in FIG.
At the moment it remains, the anode wire A_2RPotential is about Vcc
+ V_R(Accurately, (n-1) · (Vcc + V_R) / N
You. ), The EL element E that emits light_{2R, 2}Of both ends
Pressure is about Vcc + V instantly_RTry to be. Therefore, EL
Element E_{2R, 2}Has a variable current source 17_2R→ Drive switch
 16_2R→ Anode wire A_2R→ EL element E_{2R, 2}→ Scan switch
Fifteen_TwoIn addition to the route, the scanning switch 15₁→ cathode ray
B₁→ EL element E_{2R, 1}→ Anode wire A_2R→ EL element E_{2R, 2}→
Scan switch 15_TwoRoute, scan switch 15_Three→ cathode
Line B_Three→ EL element E_{2R, 3}→ Anode wire A_2R→ EL element E_{2R, 2}
→ Scan switch 15_TwoRoute, scanning switch 1
5_n→ Cathode B_n→ EL element E_{2R, n}→ Anode wire A_2R→ EL element
Child E_{2R , 2}→ Scan switch 15_TwoRoutes, multiple routes
The charging current from the battery flows in, and the battery is rapidly charged instantaneously.
As a result, the EL element E_{2R, 2}Instantaneously enters the steady light emission state.
You. Then, B_TwoDuring the scanning period of variable current source 17_2R
→ Drive switch 16_{Two R}→ Anode wire A_2R→ EL element E
_{2R, 2}→ Scan switch 15_TwoDrive current flowing from the route
The steady state is maintained by the flow.

Similarly, the EL element E_{2G, 2}The scanning switch
And at the moment the drive switch is switched
The voltage between both ends is about Vcc (more precisely, (n-1) · Vcc / n
is there. ), The EL element E_{2G, 2}Can be
Variable current source 17_2G→ Drive switch 16_2G→ Anode wire A_2G
→ EL element E_{2G, 2}→ Scan switch 15_TwoIn addition to the route
The scanning switch 15₁→ Cathode B₁→ EL element E_{2G, 1}
→ Anode wire A_2G→ EL element E_{2G, 2}→ Scan switch 15_Twoof
Route, scan switch 15_Three→ Cathode B_Three→ EL element E
_{2G, 3}→ Anode wire A_2G→ EL element E_{2G, 2}→ Scan switch 15
_TwoOf the route,..., Scanning switch 15_n→ Cathode B_n→ E
L element E_{2G, n}→ Anode wire A_2G→ EL element E_{2G , 2}→ Scan switch
Switch 15_TwoRoute, charging current from multiple routes
It flows in and instantaneously enters a steady light emitting state. Then B_TwoRun
During the inspection period, the variable current source 17_2G→ Drive switch 1
6_2G→ Anode wire A_2G→ EL element E_{2G, 2}→ Scan switch 15
_TwoDrive current flowing from the
To stay in shape.

Similarly, at the moment when the scanning switch and the drive switch are switched, the voltage between both ends of the EL element E _{2B, 2} is about Vcc + V _B (more precisely, (n−1) ·
It is _{(Vcc + V B) / n} . )
The element E _{2B, 2} has a variable current source 17 _2B → drive switch 16 _2B → anode line A _2B → EL element E _{2B, 2} → scan switch 1
In addition to the 5 ₂ of the route, scanning switch 15 ₁ → the cathode line B
₁ → EL element E _2B , 1 → Anode line A _2B → EL element E _{2B, 2} →
Scanning switches 15 ₂ routes, the scan switch 15 ₃ → the cathode line B ₃ → EL element E _{2B, 3} → anode line A _2B → EL element E _{2B, 2}
→ scanning switch 15 ₂ of the route, ..., scanning switch 1
5 _n → cathode line B _n → EL element E _{2B, n} → anode line A _2B → EL element E _{2B, 2} → scanning switches 15 ₂ route, a charging current from a plurality of routes of flow, a constant emission instantaneously .
During subsequent scanning period B ₂ is the drive current flowing from the variable current source 17 _2B → drive switches 16 _2B → anode lines A _2B → EL element E _{2B, 2} → scanning switches 15 ₂ routes, sustained steady light emission state I do.

As described above, each of the light emitting EL elements E _{2R, 2} ,
_{E 2G, 2, E 2B,} 2 almost simultaneously emitting the prescribed voltage Ve _R and switching the scanning, Ve _G, since reaching the Ve _B in a steady light emission state, the EL elements _{E 2R, 2, E 2G,} 2 , E _{2B, 2} will display a desired color without color shift. next,
The initial setting operation by the light emission control circuit 12 will be described based on the flowchart of FIG.

The light emission control circuit 12 performs an initialization routine for initialization. In the initial setting routine, as shown in FIG. 13, a command to supply a drive current over the entire scanning period is generated (step S31), and the display color of the light emitting display panel 11 is changed to white in response to the command. The user is caused to adjust the data input unit 19 so that the red, green, and blue luminance data are read from the data input unit 19 at that time (step S32), and the drive current I _R is determined according to the read luminance data. , I _G, seeking I _B (step S33), the drive current I _R, I _G, red corresponding to I _B, the voltage across Ve green and EL element for blue light emission
_R , Ve _G and Ve _B are set (step S34). Driving current I _R in the memory 20 corresponding to the luminance data, I _G, I
_B and the voltage across Ve _R, since Ve _G, the data table Ve _B are formed red, green, and each blue, the drive current I _R using the data table, I _G, I _B and the voltage across Ve _R , Ve _G and Ve _B are set.

The light emission control circuit 12 is set in step S34.
The fixed voltage Ve_R, Ve_G, Ve _BAccording to reverse via
The source voltage Vcc is set (step S35). This step
In step S35, the terminal voltage Ve_R, Ve_G, Ve_BEach voltage
The second highest voltage is compared with the reverse bias voltage V
Set as cc. Voltage Ve between both ends_R, Ve_G, Ve_BLarge
The small relation is, for example, Ve_R> Ve_G> Ve_BIf it is,
Ve_GIs set as the reverse bias voltage Vcc.
It is. In step S35, the terminal voltage Ve _R, V
e_G, Ve_BThe highest voltage and the highest
The intermediate voltage with the lower voltage is set as the reverse bias voltage Vcc.
May be specified. Voltage Ve between both ends_R, Ve_G, Ve_BNo big and small
The person in charge is, for example, Ve_R> Ve_G> Ve_B, Then (Ve
_R+ Ve_B) / 2 is the reverse bias voltage Vcc
Is set.

After execution of step S35, the light emission control circuit 12 calculates the offset voltages V _R , V _G , V _B (step S36). Offset voltages V _R, V _G, V _B is V _R = Ve
_{R -Vcc, V G = Ve G} -Vcc, is calculated as V _B = Ve _B -Vcc. The reverse bias voltage V of the former in step S35
When the cc setting method is used, the voltages Ve _R , Ve _G ,
The offset voltage corresponding to the highest terminal voltage of Ve _B is positive, the offset voltage corresponding to the next highest terminal voltage is 0 (V), and the offset voltage corresponding to the lowest terminal voltage is negative.

After the execution of step S36, the light emission control circuit 12 writes the drive currents I _R , I _G , I _B , the reverse bias voltage Vcc and the offset voltages V _R , V _G , V _B into the memory 20 and stores them (step S36). S37). In this initial setting operation, the voltages Ve _R , V
e _G, is Ve _B For _{example, Ve R = 22 (V)} , Ve G = 20
If (V) and Ve _B = 18 (V) are set, in step S35, the voltage levels of the both-end voltages Ve _R , Ve _G , and Ve _B are compared, and the second highest voltage Ve _G = 20 (V) is obtained. ) Is set as the reverse bias voltage Vcc. Therefore, step S
At 36, the offset voltages V _R , V _G , V _B are V _R = 2 (V),
V _G = 0 (V) and V _B = −2 (V) are set.

The allowable range of the offset voltage is red,
It is set individually for each of green and blue. For example, the permissible range of red V _{LLR to} V _HLR is −5 (V) to 3 (V), the permissible range of green V _{LLG to} V _HLG is −5 (V) to 2 (V), and the permissible range of blue V _LLB ＶV _HLB is -5 (V) to 1 (V). When the initial setting operation is completed, the light emission control circuit 12
Is operated by the user to perform either the brightness adjustment routine or the hue adjustment routine.

When the user operates a brightness adjustment lever (not shown) of the data input section 19, the light emission control circuit 12 executes a brightness adjustment routine according to the brightness data at that time. The brightness adjustment lever of the data input unit 19 is an operation element for adjusting the brightness of the entire display screen. Change by the same luminance.

In the brightness adjustment routine, the light emission control circuit 12 first reads the red, green, and blue luminance data output from the tint data input unit 19 (step S41) as shown in FIG. and set the drive current I _R corresponding to the blue, each of the luminance data, I _G, and I _B data table retrieved (step S42), further, the driving current I _R, I _G, red corresponding to I _B, green And the voltages Ve _R , Ve _G , Ve _B across the EL element for emitting blue light.
Is set by searching the data table (step S4).
3). The operations in steps S42 and S43 are performed in step S3.
3 and S34. As shown in FIG. 15, the data tables used in steps S42 and S43 have luminance data (32 levels of luminance) for each of red, green and blue.
Of drive currents Ir0 to Ir31 and Ig0 to Ig3 corresponding to
1, Ib0 to Ib31 and data Ver0 to Ver31,
Veg0 to Veg31 and Veb0 to Veb31 are defined.

The light emission control circuit 12 reads the reverse bias voltage Vcc stored in the memory 20 (step S4).
4), the voltages Ve _R , Ve _G , Ve _B at both ends of step S43.
Then, the offset voltages V _R , V _G , and V _B are calculated using the read reverse bias voltage Vcc (step S45). That is, the offset voltage _{V R = Ve R -Vcc, V} G = V
e _G -Vcc, is calculated as V _B = Ve _B -Vcc.

The light emission control circuit 12 calculates each of the calculated offsets.
Voltage V_R, V_G, V_BIs a voltage within the specified tolerance
It is determined whether or not this is the case (step S46). Offset voltage
Need to be set to not emit crosstalk
And the red tolerance V_LLR~ V_HLR, Green tolerance V
_LLG~ V_HLG, Blue tolerance V_LLB~ V_HLBEach restricted to
Have been. Each offset voltage V_R, V_G, V_BCorresponds to
Predetermined tolerance V_LLR~ V_HLR, V_LLG~ V_HLG, V_LLB~
V_HLB, The set driving current I_R, I _G, I_B
Variable current source 17 so that_1R, 17_1G, 17_1B~ 17
_mR, 17_mG, 17 _mB(Step S47), and
Variable voltage source 18_1R, 18_1G, 18_1B~ 18 _mR, 18_mG,
18_mBOffset voltage V that sets the output voltage of_R, V_G,
V_B(Step S48).

In step S46, any one of the offset voltages V _R , V _G , V _B corresponds to a predetermined allowable range V
_{LLR ~V HLR, V LLG ~V HLG} , if not within the V _LLB ~V _HLB, each offset voltage V _R, V _G, the predetermined voltage range is V _B corresponding V _LLR ~V _HLR, V _LLG ~V _The reverse bias voltage Vcc and the offset voltages V _R , V _G , V _B are reset so that the voltages are within _HLG , V _{LLB to} V _HLB (step S4).
9). In this step S49 resetting of the reverse bias voltage Vcc by is performed in the same manner as that in the step S35, the offset voltage V _R, V _G, resetting of V _B is the same method as in the case of step S36 Done.

After the execution of step S49, the light emission control circuit 12 controls the output voltages of the variable voltage sources 21 _{1 to} 21 _n to be the set reverse bias voltage Vcc (step S5).
0), the process proceeds to step S47, and the set drive current I _R ,
I _G, variable current source 17 so that the I _{B 1R,} 17 _1G, 17
_{1B ~17 mR,} 17 _mG, 17 controls the _mB, then proceeds to step S48 the variable voltage source _{18 1R, 18 1G, 18 1B} ~
Control is performed so that the output voltages of 18 _mR , 18 _mG , and 18 _{mB become} the set offset voltages V _R , V _G , and V _B.

After execution of step S48, the set reverse
Bias voltage Vcc, offset voltage V _R, V_G, V_BAnd drive
Dynamic current I_R, I_G, I_BIs stored in the memory 20 (step
Step S51). The brightness adjustment lever of the data input unit 19
In step S43, for example, red, green
Voltage Ve across EL element for color and blue light emission_R, Ve_G,
Ve_BIs Ve_R= 30 (V), Ve_G= 29 (V), Ve_B= 2
6 (V).
Pressure Ve_R, Ve_G, Ve_BReverse bias voltage Vcc = 2 with each
0 (V) is the offset voltage V_R, V_G, V_BCalculated as
When issued, V_R= 10 (V), V_G= 9 (V), V_B= 6
(V). As described above, the red tolerance V_LLR~ V
_HLRIs -5 (V) to 3 (V), green allowable range V_LLG~ V_HLG
Is -5 (V) to 2 (V), the allowable range V of blue_LLB~ V_HLBIs-
If it is 5 (V) to 1 (V), it is calculated in step S45.
Any offset voltage is out of the allowable range. Yo
Then, at step S49, each offset voltage V_R, V_G, V
_BAnd the reverse bias voltage Vcc is reset.
Ve_R, Ve_G, Ve_BSecond comparison of each voltage level
High voltage Ve_G= 29 (V) is the reverse bias voltage Vcc
Is reset. Each offset voltage V_R, V_G, V_BIs V_R
= 1 (V), V_G= 0 (V), V_B= -3 (V)
You.

The light emission control circuit 12
When the user operates the color adjustment lever,
A hue adjustment routine is executed according to the luminance data. This
In the hue adjustment routine of FIG.
First, the red, green,
The luminance data of each blue color is read (step S61),
Drive power corresponding to each of the red, green and blue luminance data
Style I_R, I_G, I_BSearch and set the data table
Step S62) Further, the driving current I_R, I_G, I _BCompatible with
Voltage V across the red, green and blue light emitting EL elements
e_R, Ve_G, Ve_BData table search and set
(Step S63). Operation of steps S62 and S63
Is the same as steps S33 and S34.

The light emission control circuit 12 reads the reverse bias voltage Vcc stored in the memory 20 (step S6).
4), the voltages Ve _R , Ve _G , Ve _B at both ends of step S63
The offset voltages V _R , V _G , and V _B are calculated using the read bias voltage Vcc and the read reverse bias voltage Vcc (step S65). That is, the offset voltage _{V R = Ve R -Vcc, V} G = V
e _G -Vcc, is calculated as V _B = Ve _B -Vcc.

The light emission control circuit 12 calculates each of the calculated offsets.
Voltage V_R, V_G, V_BIs a voltage within the specified tolerance
It is determined whether or not this is the case (step S66). Offset voltage
Need to be set to not emit crosstalk
And the red tolerance V_LLR~ V_HLR, Green tolerance V
_LLG~ V_HLG, Blue tolerance V_LLB~ V_HLBEach restricted to
Have been. Each offset voltage V_R, V_G, V_BCorresponds to
Predetermined tolerance V_LLR~ V_HLR, V_LLG~ V_HLG, V_LLB~
V_HLBIf the power supply is within the
Pressure Ve_R, Ve_G, Ve_BSecond highest voltage across
It is determined whether or not has changed (step S67). sand
That is, the previous end-to-end voltage Ve stored in the memory 20
_R, Ve_G, Ve_BOf the second highest voltage
The voltage between both ends of the EL device for the color
Voltage Ve between both ends_R, Ve_G, Ve_BTo a different voltage
It is determined whether or not it has been converted. Previous end voltage Ve_R, V
e_G, Ve_BFor the color that had the second highest voltage
If the voltage across the EL element has not changed, the color
The voltage across the EL element is the second highest voltage
It is determined whether or not it is (step S68). That is, before
Times voltage Ve_R, Ve_G, Ve_BSecond highest of
Voltage and the current end voltage Ve_R, Ve_G, Ve _BOut of
Is the voltage across the EL element of the same color.
It is determined whether or not there is.

As a result of the determination in step S68, the voltage between both ends of the color EL element, which was the second highest voltage last time, is 2 this time.
If it is the next highest voltage, the set drive current I _R ,
I _G, variable current source 17 so that the I _{B 1R,} 17 _1G, 17
_{1B to} 17 _mR , 17 _mG , and 17 _mB are controlled (step S6).
9) and the variable voltage sources _181R , _181G , _181B- 1.
Control is performed so that the output voltages of 8 _mR , 18 _mG , and 18 _{mB become} the set offset voltages V _R , V _G , and V _B (step S).
70).

As a result of the determination in step S66, each offset
Voltage V_R, V_G, V_BIs not within the specified tolerance
In this case, the result of determination in step S67 is that the previous end-to-end voltage Ve
_R, Ve_G, Ve_BOf the second highest voltage
If the voltage across the EL element for the changed color changes, or
As a result of the judgment in step S68, the voltage became the second highest voltage last time.
The voltage across the EL element for color is the second highest voltage this time
If not, each offset voltage V_R, V_G, V_BBut
The corresponding predetermined voltage range V_LLR~ V_HLR, V_LLG~ V _HLG, V
_LLB~ V_HLBReverse bias voltage Vcc and
And each offset voltage V_R, V_G, V_BReset (step
Step S71). The reverse bias voltage in step S71
The resetting of the pressure Vcc is performed in the same manner as in step S35 described above.
And the offset voltage V_R, V_G, V_BReconstruction
The determination is performed in the same manner as in step S36.

After the execution of step S71, the light emission control circuit 12 controls the output voltages of the variable voltage sources 21 _{1 to} 21 _n to be the set reverse bias voltage Vcc (step S7).
2) The process proceeds to step S69, where the set drive current I _R ,
I _G, variable current source 17 so that the I _{B 1R,} 17 _1G, 17
_{1B ~17 mR,} 17 _mG, 17 controls the _mB, then proceeds to step S70 the variable voltage source _{18 1R, 18 1G, 18 1B} ~
Control is performed so that the output voltages of 18 _mR , 18 _mG , and 18 _{mB become} the set offset voltages V _R , V _G , and V _B.

After the execution of step S70, the set reverse
Bias voltage Vcc, offset voltage V _R, V_G, V_BAnd drive
Dynamic current I_R, I_G, I_BIs stored in the memory 20 (step
Step S73). The color adjustment lever of the data input section 19
In operation S63, for example, red, green
Voltage Ve across EL element for color and blue light emission_R, Ve_G,
Ve_BIs Ve_R= 23 (V), Ve_G= 20 (V), Ve_B= 2
1 (V), and the voltage at both ends is set at step S65.
Pressure Ve_R, Ve_G, Ve_BReverse bias voltage Vcc = 2 with each
0 (V) is the offset voltage V_R, V_G, V_BCalculated as
When issued, V_R= 3 (V), V_G= 0 (V), V_B= 1 (V)
Becomes As described above, the red tolerance V_LLR~ V_HLRIs
-5 (V) to 3 (V), green allowable range V_LLG~ V_HLGIs -5
(V) to 2 (V), blue tolerance V_LLB~ V_HLBIs -5 (V)
If it is １1 (V), the o calculated in step S65.
The offset voltages are all within the allowable range. Previous both ends
Voltage Ve _R, Ve_G, Ve_BIs Ve_R= 22 (V), Ve_G=
20 (V), Ve_B= 18 (V), the previous 2
The second highest voltage is V, which is the voltage between both ends of the green EL element.
e_GIt is. However, the second highest voltage this time is blue
Ve, which is the voltage across the EL element for_BIt is. Therefore,
In step S61, each offset voltage V_R, V_G, V_BPassing
And the reverse bias voltage Vcc are reset, and the voltage Ve
_R, Ve_G, Ve_BSecond highest by comparing each voltage level of
Voltage Ve_B= 21 (V) as the reverse bias voltage Vcc
Is set. Each offset voltage V_R, V_G, V_BIs V_R= 2
(V), V_G= -1 (V), V_B= 0 (V) is reset.

The predetermined allowable ranges V _{LLR to} V _HLR , V _{LLG to} V _HLG , and V _{LLR of the} above-described offset voltages V _R , V _G , and V _B respectively.
_{LLB to} V _HLB are appropriately set. The upper limit values of V _HLR , V _HLG , and V _HLB are light emission threshold voltages Vth _R , Vth _G , and Vth _{B. If} the offset voltage exceeds the light emission threshold voltage, the light emission will be slight during the reset period, or a cathode ray that has not been scanned. The upper EL element may emit crosstalk light. V _LLR ,
There is no particular limitation on the lower limits of V _LLG and V _LLB . However, when power efficiency is taken into consideration, it is desirable to set it in an appropriate range. That is, the parasitic capacitance of the EL element located at the intersection of the unscanned cathode line and the driven anode line is charged with an invalid charge that does not contribute to light emission in accordance with the offset voltage. In order to reduce the amount, it is better to set the lower limit in an appropriate range.

Predetermined tolerance for each of red, green and blue
V_LLR~ V_HLR, V_LLG~ V_HLG, V_{LL B}~ V_HLBMeet the reverse
If the bias voltage Vcc cannot be set,
Voltage Ve between both ends_R, Ve_G, Ve_BIs the EL element for the largest color
Reverse bias voltage Vcc to the limit value which does not exceed the light emission threshold voltage of
Is set. Of the above-mentioned light emitting display panel
Each EL element deteriorates when it emits light for a long time, and the VI characteristics are deteriorated.
Change. For example, when the total light emission time is short, FIG.
As shown in FIG. 7, it has the VI characteristic, but the total light emission time is
When the length becomes longer, as shown in FIG.
Current I for the same value of
The example brightness L also decreases. Therefore, the total light emission time was measured.
And measure the VI characteristic appropriately according to the light emission time
It is conceivable to compensate the table. Prescribed for measurement
The current flows through the EL element at the current value intervals of
What is necessary is just to detect the voltage and calculate a coefficient for compensating.

In the above-described embodiment, the voltage Ve _R , Ve _G , and Ve _B across the EL elements for red, green, and blue light emission corresponding to the drive currents I _R , I _G , and I _B are searched in a data table. Although it is set, a function formula indicating the drive current-end voltage characteristic is stored for each of red, green and blue,
Using the function formula, the voltages Ve _R , Ve _G ,
Ve _B may be calculated.

Although a drive current is supplied from the current source to the EL element to emit light, the potential is applied from the voltage source so that a voltage slightly higher than the emission threshold voltage is applied to the EL element in the forward direction. You may give it to a line.

[0067]

As described above, according to the present invention, it is possible to equalize the voltage that changes until the voltage between both ends of each of the capacitive light emitting elements having different emission colors reaches the desired voltage during the scanning period. The rising characteristics of light emission of each of the capacitive light emitting elements having different emission colors can be improved, and color shift can be prevented even when the emission luminance is adjusted such as color tone adjustment.

[Brief description of the drawings]

FIG. 1 is a diagram showing a cross section of an organic electroluminescence element.

FIG. 2 is a diagram showing an equivalent circuit of the organic electroluminescence element.

FIG. 3 is a diagram schematically showing a driving voltage-current-emission luminance characteristic of an organic electroluminescence element.

FIG. 4 is a block diagram for explaining a light emission control operation of a conventional driving device.

FIG. 5 is a block diagram for explaining a light emission control operation of a conventional driving device.

FIG. 6 is a block diagram for explaining a light emission control operation of a conventional driving device.

FIG. 7 is a block diagram showing a schematic configuration of a display device to which the present invention is applied.

8 is a diagram specifically showing the configurations of a cathode ray scanning circuit, an anode ray drive circuit, and a light emitting display panel in the apparatus of FIG.

FIG. 9 is a flowchart illustrating a light emission control routine.

FIG. 10 is a block diagram for explaining a light emission control operation during a scanning period.

FIG. 11 is a block diagram illustrating a light emission control operation during a reset period.

FIG. 12 is a block diagram for explaining a light emission control operation in the next scanning period.

FIG. 13 is a flowchart illustrating an initialization routine.

FIG. 14 is a flowchart illustrating a brightness adjustment routine.

FIG. 15 is a diagram showing a data table.

FIG. 16 is a flowchart showing a hue adjustment routine.

FIG. 17 shows a voltage V of an EL element when the total light emission time is short.
FIG. 9 is a diagram showing a current I characteristic.

FIG. 18 shows a voltage V of an EL element when the total light emission time is long.
FIG. 9 is a diagram showing a current I characteristic.

[Explanation of symbols]

1,13 cathode line scanning circuit 2, 14 anode line drive circuit _{2 1R, 2 1G, 2 1B} ~2 mR, 2 mG, 2 mB, 17 1R, 1
_{7 1G, 17 1B ~17 mR,} 17 mG, 17 mB current source 4, 12 light emission control circuit _{5 1 ~5 n, 15 1 ~15} n scanning switches _{6 1R, 6 1G, 6 1B} ~6 mR, 6 mG, 6 _mB , 16 _1R , 1
_{6 1G, 16 1B ~16 mR,} 16 mG, 16 mB drive switches _{18 1R, 18 1G, 18 1B} ~18 mR, 18 mG, 18 mB, 2
1 ₁ through 21 _n variable voltage source 11 emitting display panel _{A 1R, A 1G, A 1B} ~A mR, A mG, A mB anode lines B ₁ .about.B _n cathode lines _{E 1R, 1, E 1G,} 1, E 1B, _{1 to EmR, n} , _{EmG, n} , _{EmB, n} organic electroluminescent devices

Continuation of the front page (72) Inventor Shinichi Ishizuka 6-1-1 Fujimi, Tsurugashima-shi, Saitama F-term in Pioneer Corporation R & D Center (Reference) 5C080 AA06 BB05 CC03 DD05 DD30 EE29 EE30 FF12 GG12 JJ02 JJ03 JJ05 JJ06 JJ07

Claims (5)

[Claims] A plurality of drive lines and a plurality of scan lines that intersect each other, and a polarity connected between the scan lines and the drive lines at each of a plurality of intersections between the drive lines and the scan lines. A driving device for a multicolor light emitting display panel, comprising a plurality of capacitive light emitting elements divided into a plurality of types according to emission colors, wherein the same type of capacitive light emitting elements are arranged on the same drive line. A scanning period for selecting one of the plurality of scanning lines and a subsequent reset period are repeatedly set according to a scanning timing of the input image data, and the scanning period is set according to the input image data during the scanning period. Control means for designating a current drive line corresponding to a capacitive light emitting element to emit light on one scanning line; applying a first potential to the one scanning line during the scanning period; Scanning means for applying a second potential higher than the first potential to scanning lines other than the scanning lines and applying the first potential to all the scanning lines during the reset period; A drive current is supplied to the current drive line in order to apply a voltage to the capacitive light emitting element to be emitted in the forward direction, and the capacitive light emitting element to be emitted in the next scanning period during the reset period. Drive means for supplying a third potential to the next drive drive line for applying an offset voltage equal to or less than the light emission threshold voltage, and operation input means for outputting luminance data indicating a luminance level of each of the emission colors in response to an operation input Setting means for setting each level of the drive current and the voltage across the capacitive light emitting element of a type corresponding to each of the emission colors according to the luminance data based on predetermined data; First adjusting means for adjusting the drive current to a level set by the setting means; and the two ends set by the setting means so as to correspond to the type of the capacitive light emitting element. Calculating means for setting a level difference from a voltage as the third potential; and determining whether each level of the third potential calculated by the calculating means for each type of the capacitive light emitting element is within a predetermined allowable range. Determination means for determining whether or not each of the levels of the third potential calculated by the calculation means for each type of the capacitive light emitting element is within a predetermined allowable range; The potential is adjusted, and when at least one of the calculated levels of the third potential is not within a predetermined allowable range, each level of the third potential is within a predetermined allowable range for each emission color. Driving device for a multi-color light-emitting display panel, characterized in that and a second adjusting means for adjusting the levels of said second potential and said third potential to. 2. The method according to claim 1, wherein when the at least one of the calculated levels of the third potential is not within a predetermined allowable range, the second adjusting unit sets the level of each of the capacitive light emitting elements by the setting unit. 2. The driving device for a multicolor light emitting display panel according to claim 1, wherein a second highest voltage level of the set both-end voltages is set as the level of the second potential. 3. The method according to claim 2, wherein at least one of the calculated levels of the third potential is not within a predetermined allowable range. 2. The driving device for a multicolor light emitting display panel according to claim 1, wherein an intermediate level between a highest voltage level and a lowest voltage level among the set both-end voltages is set as the level of the second potential. . 4. The driving apparatus for a multicolor light emitting display panel according to claim 1, wherein an upper limit of the predetermined allowable range is the light emission threshold voltage. 5. The driving device for a multicolor light emitting display panel according to claim 1, wherein said capacitive light emitting device is an organic electroluminescence device.