JP2001042821A - Display device and driving circuit of display panel - Google Patents

Abstract

PROBLEM TO BE SOLVED: To make suppressible picture degradation at the time of constituting an anode line drive circuit of plural IC chips by constituting of the driving circuit of first and second driving circuits that supply divided light emitting driving currents of respective specific ratios to a first electrode line. SOLUTION: A first driving circuit among driving circuits supplies a divided light emitting driving current having a (n-m)/n (where m and n are natural numbers) of a light emitting driving current to a first electrode line and supplies a light emitting driving current to each of plural first electrode lines arranged in adjacent to one side of the first electrode line. Moreover, the first driving circuit supplies m/n divided light emitting driving currents and supplies light emitting driving currents to each of plural first electrode lines arranged adjacent to the other side of the first electrode line. For example, first and second anode lines drive circuits 21 and 22 are made up with a reference current control circuit RC, a switch block SB and transistors Q1 to Qn as first and second driving circuits.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a display device using a display panel comprising a self-luminous element such as an organic electroluminescence element, and a driving circuit for the display apparatus.

[0002]

2. Description of the Related Art As a self-luminous element for realizing a thin and low power consumption display device, an organic electroluminescence (hereinafter referred to as EL) element is known. FIG. 1 is a diagram showing a schematic configuration of such an EL element. FIG.
As shown in FIG. 1, an EL element is composed of at least one organic functional layer 102 composed of an electron transport layer, a light emitting layer, a hole transport layer, and the like on a transparent substrate 100 composed of a glass plate or the like on which a transparent electrode 101 is formed. , And the metal electrode 103 are stacked.

FIG. 2 is an equivalent circuit that electrically shows the characteristics of such an EL element. As shown in FIG. 2, the EL element can be replaced by a capacitance component C and a diode characteristic component E coupled in parallel with the capacitance component.
Here, the positive electrode of the transparent electrode 101 and the metal electrode 10
When a negative voltage is applied to the cathode of No. 3 and a direct current is applied between the transparent electrode and the metal electrode, charges are accumulated in the capacitance component C. At this time, when the barrier voltage or the emission threshold voltage inherent to the EL element is exceeded, a current starts to flow from the electrode (the anode side of the diode component E) to the organic functional layer serving as the light emitting layer, and the organic functional layer has an intensity proportional to the current. 102 emits light.

FIG. 3 is a diagram showing a schematic configuration of an EL display device for displaying an image using an EL display panel in which a plurality of the above EL elements are arranged in a matrix. In FIG. 3, an ELDP 10 as an EL display panel includes cathode lines (metal electrodes) B _{1 to} B _n carrying first to n-th display lines, and these cathode lines B _{1 to} B _n.
1 .about.B _n each are crossed to arranged the m-number of anode lines (transparent electrodes) A ₁ to A _m are formed. These cathode rays B _{1 to} B _n
And anode lines A ₁ to A each crossed portion of _m (n × m pieces)
Then, EL elements E _{11 to} E _nm having the above-described structure are formed. Note that each of these EL elements E _{11 to} E _nm is
The ELDP 10 serves as one pixel.

[0005] The light emission control circuit 1 is provided for one input screen.
The image data of (n rows, m columns) is converted into each pixel of ELDP10,
That is converted into the EL element E ₁₁ to E _nm each pixel data group D ₁₁ to D _nm corresponding to the, as it is shown them in Figure 4, sequentially for each row, supplied to the anode line drive circuit 2 Go. For example, the pixel data D ₁₁ to D _{1 m,} ELD
M data bits for designating whether or not to emit light for each of the EL elements E _{11 to} E _1m belonging to the first display line of P10. Each of the data bits is “1” when the logic level is “1”. If the light emission is “0” and the logic level is “0”, it indicates “non-light emission”.

The light emission control circuit 1 is shown in FIG.
In synchronization with the supply timing of pixel data for each row as described above.
The first display line to the n-th display line of the ELDP 10
The scanning line selection control signal to be sequentially scanned
Supply to Road 3. First, the anode wire drive circuit 2
From m data bits in the pixel data group, "
All data bits of logic level "1" that specify "light emission"
Extract. Next, it corresponds to each of the extracted data bits.
Anode wire belonging to the "column" ₁~ A_mEverything from within
Select, connect the constant current source only to this selected anode wire,
A predetermined pixel drive current i is supplied.

[0007] The cathode line scanning circuit 3 includes the cathode lines B _{1 to} B _n.
Among them, the cathode line corresponding to the display line indicated by the scanning line selection control signal is selectively selected and set to the ground potential, and a predetermined high potential V _{CC is applied} to each of the other cathode lines. Each is applied. In addition, such a high potential V _CC
Is set to substantially the same value as the voltage between both ends (the voltage determined based on the amount of charge to the parasitic capacitance C) when the EL element emits light at a desired luminance.

At this time, a light emission drive current flows between the "column" to which the constant current source is connected by the anode line drive circuit 2 and the display line set to the ground potential by the cathode line scan circuit 3. The EL element formed crossing the flow, the display line and the "column" emits light according to the light emission drive current. On the other hand, no current flows between the display line set to the high potential V _CC by the cathode line scanning circuit 3 and the “column” to which the constant current source is connected. The EL elements formed so as to cross each other remain non-light emitting.

The above operation is performed by the pixel data groups D _{11 to} D _11.
1m , D _{21 to} D _2m ,..., D _{n1 to} D _nm , the light emission pattern for one field corresponding to the input image data is displayed on the screen of the ELDP 10, that is, The image is displayed. Here, in recent years, in order to realize a large screen of a display panel, a display line,
That is, while increasing the number of the cathode wires B, the anode wires A
It has become necessary to increase the number of screens to achieve higher definition of the screen. Accordingly, as the number of the anode lines A and the number of the cathode lines B increase, the circuit scale of each of the anode line drive circuit 2 and the cathode line scanning circuit 3 also increases. There is a concern about deterioration. Therefore, it has been considered that each of the anode line drive circuit 2 and the cathode line scanning circuit 3 is constructed by a plurality of IC chips.

However, if the anode line drive circuit 2 is constructed by a plurality of IC chips, the anode line drive circuit 2 may vary due to manufacturing variations.
There may be a difference in the value of the light emission drive current to be supplied to the anode line between the IC chips. Therefore, there is a problem that areas having different luminances are formed on the screen of the ELDP 10 due to the difference in the light emission drive current, and in particular, there is a problem that the luminance step on the boundary degrades the image quality.

[0011]

SUMMARY OF THE INVENTION The present invention has been made to solve such a problem, and a display device capable of suppressing image quality deterioration when an anode line drive circuit is constructed with a plurality of IC chips. And a driving circuit of the display panel.

[0012]

A display device according to the present invention has a light emitting element at each intersection of a plurality of first electrode lines and a plurality of second electrode lines arranged to cross each of the first electrode lines. And a drive circuit for supplying a light emission drive current for driving each of the light emitting elements to each of the first electrode lines, wherein the drive circuit comprises: A divided light emission drive current having a current amount of (n−m) / n 、 n> m: n, where m is a natural number｝ is supplied to at least one of the first electrode lines. A first drive circuit for supplying the light-emission drive current to each of a plurality of first electrode lines arranged adjacent to one side of the one first electrode line, and the first electrode The line indicates m / m of the emission drive current.
n ｛n> m: n and m each supply a divided light emission drive current of a natural amount｝ and each of the first electrode lines arranged adjacent to the other side of the one first electrode line And a second drive circuit for supplying the light emission drive current to the second drive circuit.

Further, in the display panel driving circuit according to the present invention, a light emitting element is provided at each intersection of a plurality of first electrode lines and a plurality of second electrode lines arranged so as to cross each of the first electrode lines. A drive circuit for driving a formed display panel to emit light, wherein the light-emitting drive current source supplies a light-emitting drive current for causing the light-emitting element to emit light to a part of the first electrode lines. And at least one of the first electrode lines adjacent to the first electrode line group has the light emission drive current of (nm) / n ｛n> m: n, where m is a natural number｝, and the light emission drive is divided. And a split light emission drive current source for supplying a current.

[0014]

Embodiments of the present invention will be described below in detail with reference to the drawings. FIG. 5 is a diagram showing a schematic configuration of an EL display device according to the present invention. In FIG. 5, an ELDP 10 'as an EL display panel has cathode lines carrying each of a first display line to an n-th display line.
(Metal electrode) B ₁ ~B _n and, these cathode lines B ₁ .about.B _n each crossover to arrayed 2m-1 pieces of anode lines (transparent electrodes) A ₁ ~
A _{2m- 1} is formed. To each of these cathode lines B ₁ .about.B _n and cross portions of anode lines A ₁ ~A _2m-1, EL element E _{1, 1} to E n having such the structure described above, _2m-1 is formed. Each of these EL elements E _{1,1 to} En _{, 2m-1} is
It is responsible for one pixel as the LDP 10 '.

The light emission control circuit 1 'supplies a scanning line selection control signal for sequentially scanning each of the first display line to the n-th display line of the ELDP 10' to the cathode line scanning circuit 30, as shown in FIG. . The cathode line scanning circuit 30 selectively selects a cathode line corresponding to the display line indicated by the scanning line selection control signal from the cathode lines B _{1 to} B _n of the ELDP 10 ′, grounds the cathode line to ground potential, and A predetermined high potential _Vcc is applied to each of the other cathode lines.

The light emission control circuit 1 'converts the input image data for one screen (n rows, 2m-1 columns) into an ELDP 10'.
, I.e. _, pixel data D _{1,1 to} D _{n, 2m-1} corresponding to each of the EL elements E _{1,1 to} En _{, 2m-1,} and converts the pixel data into first to m-th columns. Belonging to, and the m-th column to the 2m-1
Divide into those that belong to a column. At this time, pixel data D _{1,1 to} D _{1, m} , D _{2,1 to} D _{2, m} , D _3,1 obtained by grouping pixel data belonging to the first to m-th columns for each display line. ~
D _2, m, · · · ·, and D _n, 1 to D _n, the _m each, as the first drive data GA _1-m such is shown in Figure 6, sequentially, with the first anode line drive circuit 21 Supply. At the same time, the light-emission control circuit 1 ′ generates pixel data D _{1, m to} D _1,2m−1 , D ₂ obtained by grouping pixel data belonging to the m-th to 2m−1 columns for each display line. _{, m} ~ D _2,2m-1 , D _{3, m} ~
_D 3,2m-1, ····, and D _n, m to D _n, the _2m-1, respectively, as is but such second drive data GB _1-m shown in FIG. 6, sequentially,
It is supplied to the second anode line drive circuit 22. As shown in FIG. 6, each of the first drive data GA _1-m and the second drive data GB _1-m is sequentially transmitted to the first anode line drive circuit in synchronization with the scanning line selection control signal. 21st and 2nd
It is supplied to each of the anode line drive circuits 22. On this occasion,
The first drive data group GA _{1 -m} refers to m ELs belonging to each of the first to m-th columns of each display line of the ELDP 10 ′.
M data bits that specify whether or not to emit light for each of the elements. The second drive data group GB _{1 -m} is the _m- th of each display line of the ELDP 10 ′.
These are m data bits that specify whether or not to emit light for each of the m EL elements belonging to each of the column to the (2m-1) th column.

FIG. 7 is a diagram showing an internal configuration of each of the first anode line drive circuit 21 and the second anode line drive circuit 22 as a drive circuit according to the present invention. In addition, the first
Anode line drive circuit 21 and second anode line drive circuit 2
2 are respectively constructed in two different IC chips. As shown in FIG. 7, each of the first anode line drive circuit 21 and the second anode line drive circuit 22 includes a reference current control circuit RC, a switch block SB, and m transistors Q _{1 to} Q _m as current drive sources. And the resistances R _{1 to} R _m
Consists of

Transistor in reference current control circuit RC
TA Q_bThe resistor R₀Via a predetermined voltage V_BEContact
Connected to its base and collector
TA Q _aThe collector is connected. For operational amplifier OP
Is a predetermined reference potential V_REFAnd the transistor Q_aEmitter of
Potential is input and the output potential is
Q_aIs entered at the base of Transistor Q_aEmitter of
Is the resistance R_PIs grounded to the ground potential. Less than
With the above configuration, the transistor Q_aCollector d
Reference current I between transmitters_REF(= V_REF/ R_P)
And

A predetermined potential V _BE is applied to the emitter of each of the transistors Q _{1 to} Q _m via each of the resistors R _{1 to} R _m , and the base of each of the transistors Q _b
The base is connected. At this time, the resistance values of the resistor R ₀ and R _{1 to} R _{m have} a relationship of R ₀ = R ₁ = R ₂ ... = R _m-1 R _m = 2 · R ₁ .

In short, among the resistances R ₀ and R _{1 to} R _m ,
Each of the resistances R ₀ and R _{1 to} R _m-1 has the same resistance value, and only the resistance R _m has twice the resistance value. Further, each of the transistors Q ₁ to Q _m are those having the transistors Qa and Qb and same characteristics.

Therefore, the reference current control circuit RC and the transistors Q _{1 to} Q _m constitute a current mirror circuit, and the reference current control circuit RC and the transistors Q _{1 to} Q _m-1 are connected between the emitter and collector of each of the transistors Q _{1 to} Q _m-1. The light emission drive current i having the same current value as the current I _REF flows. On the other hand, between the emitter and the collector of the transistor Q _m, the resistance R _m is the resistance R
Since it is twice the resistance value of ₁ to R _{m -1,} so that the light emission drive current i / 2 is the half of the current of the reference current I _REF flows.

The switch block SB receives the light emission drive current from each of the transistors Q ₁ -Q _m at the output terminal X
₁ to X _m m-number of switching devices S ₁ ~ to derive each of the
S _m is provided. At this time, the switch block SB of the first anode line drive circuit 21, according to the logic level of the first drive data GA ₁ ~GA _m respectively supplied from the light emission control circuit 1 ', the switching element S ₁ to S _m are independently turned on / off. For example, when the first drive data GA ₁ is at the logic level “0”, the switching element S ₁ in the switch block SB of the first anode line drive circuit 21 is turned off, while the first drive data GA ₁ is at the logic level. when "1", it derives the light emission drive current i supplied from the transistor Q ₁ in the oN state to the output terminal X _1. When the first drive data GA _m is at the logical level “0”, the first anode line drive circuit 2
Switching element S in one switch block SB
While _m is to be turned off, to derive the light emission drive current i / 2 supplied from the transistor Q _m in the ON state to the output terminal X _m in the case of the logic level "1".

On the other hand, in the switch block SB of the second anode line drive circuit 22, according to the logic level of the second drive data GB _m ~GB ₁ respectively supplied from the light emission control circuit 1 ', the switching element S ₁ ~ On / off control of each S _m is performed independently. For example, when the second drive data GB _m is a logic level "0", the second anode line drive circuit 22
Switching element S ₁ in the switch block SB of FIG.
Whereas the OFF state, according the second drive data GB _m derives to the output terminal X ₁ a light emission drive current i supplied from the transistor Q ₁ in the ON state when the logic level "1". Further, when the second drive data GB ₁ is logic level "0", the switching elements S _m in the switch block SB of the second anode line drive circuit 22 whereas in the off state, when the logic level "1" the light emission drive current i / 2 supplied from the transistor Q _m in the oN state is derived to an output terminal X _m.

Here, the output of the first anode line drive circuit 21
Power end X₁~ X_mFigure 5 or even on the actual IC chip
Are arranged in the form as shown in FIG.
0 'anode wire A₁~ A_mDerive the emission drive current for each of
You. On the other hand, the output terminal X of the second anode line drive circuit 22_m~
X₁Are also in the form as shown in FIG. 5 or FIG.
ELDP10 'which is arranged on an actual IC chip
Anode wire A_m~ A_2m-1Derive the emission drive current for each of
You. At this time, the output terminal X of the first anode line drive circuit 21 _m
And the output terminal X of the second anode line drive circuit 22_mIs that
Other output terminals (X₁~ X_{m- 1}), And
Output terminal X of second anode line drive circuit 22_mIs the other
Output terminal group (X_m-1~ X₁), And EL
Anode wire A of DP10 '_mConnected in common.

That is, the anode wire A of the ELDP 10 '₁~
A_2m-1Of which, anode wire A₁~ A_m-1Are the first anode wire drivers
Eve circuit 21, anode wire A_{m + 1}~ A_2m-1Each is a second anode
Are driven by the line drive circuits 22,
Receives supply of stream i. However, the screen of ELDP10 '
Within the anode wire A₁~ A_m-1Screen area DE_LWhen,
Anode wire A_{m + 1}~ A_2m-1Screen area DE_ROn the border with
Anode wire A located_mAre the first anode line drive circuit 21 and
And the second anode line drive circuit 22.
That is, the resistance R_m, Transistor Q_mAnd switching
Element S _mVia the first anode line drive circuit 21 and the second
Output terminal X of each anode line drive circuit 22_mDerived from
The light emission drive current i / 2 is calculated as shown in FIG.
It is added by ear connection, and as a result
Flow i is anode wire A_mIt is supplied to.

FIG. 8 is a diagram showing an example of the luminance state on the screen when all the EL elements E _{1,1 to} En _{, 2m-1} of the ELDP 10 'emit light. In FIG. 8,
It is assumed that the current drive capability of the second anode line drive circuit 22 is only 98% of that of the first anode line drive circuit 21. That is, the light emission drive current i output from the first anode line drive circuit 21 is
Output light emission current is 0.98 · i.

At this time, the light emission drive current is proportional to the light emission luminance of the EL element. Therefore, as shown in FIG. 8, the light emission luminance in the screen area DE _L of anode lines A ₁ to A _m-1 driven by the first anode line drive circuit 21 plays "10
"When light emission luminance of the screen area DE _R where the anode line A _{m + 1} ~A _2m-1 driven by a second anode line drive circuit 22 plays the" 0 becomes 98 ".

On the other hand, the screen area DE_LAnd the screen area
DE_RAnode line A located on the border with _mHas the first anode wire
The light emission drive current (i / 2) from the drive circuit 21 and the second
The emission drive current (0.98 · i /
2), that is, (0.99 · i / 2) = (i / 2) + (0.98 · i / 2).

Therefore, as shown in FIG.
screen _{area m} plays, that screen area DE _L and screen area D
E emission luminance in the boundary region between the _R, said screen area DE _L,
And an intermediate luminance "99" of the luminance in the screen area DE _R each. Accordingly, occurs disparity was constructed by the first anode line drive circuit 21 and the second anode line drive circuit 22 each independently an IC chip because both the current driving capability, and the screen region DE _L, in the screen area DE _R be gone can luminance difference, the luminance is the region DE _L at the boundary area, since an intermediate luminance between the DE _R, the luminance level difference on the screen becomes gentle.

In the above embodiment, the number of anode lines of the ELDP 10 'to be driven is odd (A ₁ to A ₁ ).
A _2m-1 ), but the same is applicable even if the number of anode wires is even. Further, in the above embodiment, although the one of the number of anode lines responsible for the boundary region between the screen region DE _L and the screen region DE _R (anode line A _m), may be plural.

FIG. 9 shows a first anode line drive circuit 21 and a second anode line drive circuit 2 made in view of this point.
FIG. 2 is a diagram illustrating a connection state between these drive circuits and an ELDP 10 ′. Each of the first anode line drive circuit 21 and the second anode line drive circuit 22 shown in FIG. 9 is the same except that the resistance value of the resistor Rm _-1 is different from the configuration shown in FIG.

That is, the resistance values of the resistors R ₀ and R _{1 to} R _{m in} the first anode line drive circuit 21 and the second anode line drive circuit 22 shown in FIG. 9 are as follows: R ₀ = R ₁ = R ₂ ... = R _m-2 R _m-1 = R _m = 2 · R ₁

In short, among the resistances R ₀ and R _{1 to} R _m ,
Each of the resistances R ₀ and R _{1 to} R _m−2 has the same resistance value, and the resistances R _m and R _m−1 have twice the resistance value. Therefore, a light emission drive current i having the same current value as the reference current I _REF flows between the emitters and collectors of the transistors Q _{1 to} Q _m-2 , while the emitters / collectors of the transistors Q _m-1 and Q _m A light emission drive current i / 2, which is a half of the reference current _IREF , flows between the collectors.

Here, as shown in FIG. 9, the output terminals X _{1 to} X _m of the first anode line drive circuit 21 are connected to ELDP1
It is connected to each of the anode lines A ₁ to A _m 0 '. on the other hand,
Output X _m to X ₁ of the second anode line drive circuit 22, FIG. 9
As shown in the figure, the anode lines A _{m to} A
It is connected to each of _2m-2 . At this time, the output terminal X _m-1 of the first anode line drive circuit 21, the output end X _m of the second anode line drive circuit 22, the anode line A _m-1 of ELDP10 '
Connected in common. Further, the output terminal X _m of the first anode line drive circuit 21, the output terminal X _m-1 of the second anode line drive circuit 22 are commonly connected to the anode line A _m of ELDP10 '.

That is, the anode lines A ₁ to ELDP 10 ′
Of the A _2m-2 , each of the anode lines A _{1 to} A _m−2 is driven by the first anode line drive circuit 21, and each of the anode lines A _{m + 1 to} A _2m−2 is driven by the second anode line drive circuit 22. Then, each receives the supply of the light emission drive current i. However, the screen area DE _L responsible anode line A ₁ ~A _m-2 in the screen ELDP10 ',
Anode line A _{m + 1} to A _2m-2 is located on the boundary between the screen region DE _R responsible anode line A _m-1 and A _m are the first anode line drive circuit 21 and the second anode line drive circuit 22 Driven from both. That is, the first anode line drive circuit 21 is connected via the resistor R _m , the transistor Q _m , and the switching element S _m.
A light emission drive current i / 2 which is derived from the output end X _m of the resistance R _m-1, the transistor Q _m-1, and the switching elements S
The output terminal Xm _-1 of the second anode line drive circuit 22 via _m-1
The light emission drive current i obtained by adding the light emission drive current i / 2 derived from the _above is supplied to the anode line Am. Further, the resistance R _{m −1} ,
The light emitting drive current i / 2 derived from the output terminal X _{m-1 of} the first anode line drive circuit 21 via the transistor Q _m-1 and the switching element S _m-1 , the resistance R _m , the transistor Q _m , and light emission driving current i derived from the output end X _m and emission drive current i / 2 is added to the second anode line drive circuit 22 is supplied to the anode line a _m-1 through the switching element S _m It is.

According to such a configuration, the number of anode lines responsible for the boundary region between the screen region DE _L and the screen region DE _R is 2 (A
_m-1 , A _m ), so that the screen area DE on the screen
And _L, the luminance step between the screen region DE _R is compared with the case of FIG. 7, so as to become loose. In the embodiment shown in FIG. 9, the first anode line drive circuit 21 and the second anode line drive circuit 22 each output terminal X _m and X _m-1 respectively from the same light emission drive current i / 2 Although they are derived, they need not be the same light emission drive current.

For example, when each of the first anode line drive circuit 21 and the second anode line drive circuit 22 is formed into an IC using different packages, IC ₁ (first anode line drive circuit 21) and IC ₂ (second anode line drive circuit 21) When the relationship of the average current consumption with the line drive circuit 22) is IC ₁ > IC ₂ , as shown in FIG. 10, each of the first anode line drive circuit 21 and the second anode line drive circuit 22 husband from the output terminal X _m-1 s-emitting driving current 2i / 3, the output terminal X _m
Derives a light emission drive current i / 3 respectively. At this time, the first
The light emission drive current 2i / 3 derived from the output terminal X _{m-1 of the} anode line drive circuit 21 and the second anode line drive circuit 22
Anode line A of the light emission drive current i and a light emitting driving current i / 3 derived obtained by adding the output end X _m ELDP10 '
supply to _m-1 . The first anode line drive circuit and the light emission drive current i / 3 derived from the output end X _m of 21, the second anode line drive circuit output terminal X _m-1 light emission drive current 2i / 3 derived from the 22 preparative supplies light emission drive current i obtained by adding to the anode line a _m.

[0038] Thus, in the embodiment shown in FIG. 10, the anode line A _m-1 and A _m of ELDP10 by adding the light emission drive current IC ₁ and IC ₂ respectively occurs' Upon respectively supplied , the average current consumption IC ₁ side anode line a _m-1 of a large made is the addition ratio of the light emission drive current from the output end X _m-1 IC ₁ 'side average consumed current becomes large large (2 / 3).

According to such a configuration, as shown in FIG.
Anode line driven by the first anode line drive circuit 21
A₁~ A_m-1Screen area DE_LAnd the second anode wire dry
Anode line A driven by the active circuit 22_{m + 1}~ A_2m-1Picture taken by
Surface area DE_RIn the boundary area between
It changes gradually in two stages. In addition,
In the embodiment, the transistor Q as the light emission drive current source is used.
₁~ Q_mUsing bipolar transistors
As mentioned, MOS (Metal Oxide Semiconductor)
It may be realized by a resistor. At this time, FIG.
The resistance R shown in FIG.₁~ R_mOmit and Transis
TA Q₁~ Q_mEach structure, that is, channel length (or channel)
By changing the (channel width), the light emission
A transistor for outputting a drive current i, and a light emission drive current i
A transistor that outputs / 2 is constructed. An example
For example, a transistor Q that outputs a light emission drive current i ₁No
Channel width to W₁, Channel length L₁And when
In order to output the drive current i / 2, the transistor Q_m
Channel width W_TwoAnd channel length L_TwoEach, W_Two/ L_Two= (1/2) ・ (W₁/ L₁) A structure that satisfies the following relationship:

[0040]

As described above, according to the present invention, when the anode line drive circuit is constructed by a plurality of IC chips,
Even if two display areas having different luminances are formed on the display due to a difference in current driving capability between chips, the luminance at the boundary between the display areas is the intermediate luminance of each of the display areas. Therefore, visually, the luminance step becomes gentle, and the deterioration of the image quality is suppressed.

[Brief description of the drawings]

FIG. 1 is a sectional view of an organic electroluminescence element.

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

FIG. 3 is a diagram showing a schematic configuration of an EL display device.

FIG. 4 is a diagram showing supply timings of pixel data and a scanning line selection control signal by a light emission control circuit 1;

FIG. 5 is a diagram showing a schematic configuration of an EL display device according to the present invention.

FIG. 6 is a diagram showing supply timings of pixel data and a scanning line selection control signal by a light emission control circuit 1 ′.

FIG. 7 is a diagram showing an internal configuration of a first anode line drive circuit 21 and a second anode line drive circuit 22 as drive circuits according to the present invention, and a connection between each of these drive circuits and an anode line A of the ELDP 10 '. .

FIG. 8 is a diagram showing a luminance state on the screen of the ELDP 10 ′.

FIG. 9 is a diagram showing another example of connection between the first anode line drive circuit 21 and the second anode line drive circuit 22, and the anode line A of the ELDP 10 ′.

FIG. 10 is a diagram showing another example of the connection between the first anode line drive circuit 21 and the second anode line drive circuit 22 and the anode line A of the ELDP 10 ′.

FIG. 11 shows an ELDP1 according to the embodiment shown in FIG.
It is a figure which shows the brightness state on the screen of 0 '.

[Explanation of symbols]

1 'emission control circuit 10' ELDP 21 first anode line drive circuit 22 second anode line drive circuit 30 cathode line scan circuit A ₁ to A _m anode lines B ₁ .about.B _n cathode lines Q ₁ to Q _m transistor R ₁ to R _m Resistance RC Reference current control circuit

Claims (12)

[Claims] A display panel having a light emitting element formed at each intersection of a plurality of first electrode lines and a plurality of second electrode lines arranged to cross each of the first electrode lines; A drive circuit for supplying a light emission drive current for driving each element to emit light to each of the first electrode lines, wherein the drive circuit comprises at least one of the first electrode lines. (Nm) / n ｛n> m: n, where m is a natural number｝, and supplies a divided light emission drive current to the first electrode line and one of the first electrode lines. A first drive circuit for supplying the light emission drive current to each of a plurality of first electrode lines arranged adjacent to the first electrode line; and m / n of the light emission drive current to the one first electrode line.
{N> m: where n and m are natural numbers} and supply the divided light emission drive currents to each of the first electrode lines arranged adjacent to the other side of the one first electrode line. A second drive circuit for supplying the light emission drive current. 2. The display device according to claim 1, wherein each of the light emitting elements is an organic electroluminescence element. 3. The first drive circuit and the second drive circuit each include a plurality of light emission drive current sources for generating the light emission drive current, and at least one split light emission drive current for generating the split light emission drive current. A display device according to claim 1, comprising a source. 4. The display device according to claim 3, wherein each of the light emission drive current source and the split light emission drive current source is formed of a MOS transistor. 5. The MOS as the light emission drive current source
Transistor channel width W ₁ and channel length L
_1, the channel width W ₂ and the channel length L ₂ of the MOS transistor as the divided light emission drive current _{source, W 2 / L 2 = (} 1/2) · (W 1 / L 1) made to satisfy the relation The display device according to claim 4, wherein: 6. A scanning circuit for sequentially applying a ground potential to each of the second electrode lines and applying a predetermined high potential to all of the other second electrode lines to which the ground potential is not applied. The display device according to claim 1, further comprising: 7. The display device according to claim 1, wherein each of the first drive circuit and the second drive circuit is constructed in two different IC chips. 8. A display panel in which a light emitting element is formed at each intersection of a plurality of first electrode lines and a plurality of second electrode lines arranged so as to cross each of the first electrode lines to emit light. A drive circuit, comprising: a light-emitting drive current source that supplies a light-emitting drive current for causing the light-emitting element to emit light to a part of the first electrode line groups; and a light-emitting drive current source adjacent to the first electrode line group. (Nm) / n ｛n> m of the emission drive current to at least one of the first electrode lines:
A driving circuit for a display panel, comprising: a divided light emission drive current source for supplying a divided light emission drive current having a natural number 自然. 9. The driving circuit according to claim 8, wherein each of the light emitting elements is an organic electroluminescence element. 10. The drive circuit according to claim 8, wherein each of said light emission drive current source and said divided light emission drive current source is comprised of a MOS transistor. 11. The MO as the light emission drive current source
Channel width W ₁ and channel length L _{1 of} S transistor
And the channel width W ₂ and the channel length L ₂ of the MOS transistor as the divided light emission drive current source satisfy a relationship of W ₂ / L ₂ = (1/2) · (W ₁ / L ₁ ). The driving circuit according to claim 8, wherein 12. The driving circuit is constructed in a one-chip IC chip, and supplies the divided light emission driving current to the first IC chip.
The output terminal for leading out to the electrode line is arranged at at least one end of both ends of the output terminal group for leading out the light emission drive current to the first electrode line group. Item 9. The driving circuit according to Item 8.