KR100560455B1 - A De-multiplexer of light emitting display - Google Patents

Abstract

The present invention relates to a demultiplexer having a layout structure for each of RGB data in a data driver of a light emitting display device.

A demultiplexer of a light emitting display device according to the present invention is connected to a data line, and is a red and green in a demultiplexer for selectively providing a data voltage transmitted to a pixel circuit of a light emitting display device according to a control signal. A plurality of shift registers having first, second, third and fourth shift registers for shifting and outputting the input signal levels of the data driver for current driving the blue pixels and the blue pixels, respectively; And a plurality of switches for selecting the plurality of shift registers according to respective selection signals, wherein the plurality of shift registers are arranged in a first direction for each group, each of which is a group of two. It is done.

According to the present invention, in the data driver of the light emitting display device, by vertically arranging the shift registers of the demultiplexer, the lateral pitch of the layout can be reduced, thereby ensuring the flexibility of layout design.

Organic EL, light emitting display, data driver, demultiplexer, pitch, vertical structure

Description

A de-multiplexer of light emitting display

1A and 1B are diagrams showing the light emission principle and organic EL light emitting cells of organic EL, respectively.

2 is a schematic block diagram of an organic EL display device.

3 is a diagram showing a general organic EL display panel using an active driving method using a TFT.

FIG. 4 is a diagram representatively showing one of N × M pixel circuits of the display panel of FIG. 3.

5 is a diagram illustrating an example of a demultiplexer of a light emitting display device according to the related art.

6 is a diagram illustrating a demultiplexer layout structure of a light emitting display device according to the related art.

7 is a diagram illustrating a demultiplexer layout structure of a light emitting display device according to an exemplary embodiment of the present invention.

8 is a circuit diagram of a demultiplexer of a light emitting display device according to an exemplary embodiment of the present invention.

FIG. 9 is a diagram illustrating an example of a demultiplexer layout structure according to the circuit of FIG. 8.

The present invention relates to a demultiplexer of a light emitting display device, and more particularly, to a demultiplexer having a layout structure for each of RGB data in a data driver of the light emitting display device.

An organic electroluminescence (EL) display device is a device for displaying an image by controlling an amount of current flowing through these organic materials by dividing an organic material emitting light when the current flows into pixels in a matrix form. Such an organic EL display device is expected to be a next generation display device due to advantages such as low voltage driving, light weight, wide viewing angle, and high speed response.

1A and 1B are diagrams showing the light emission principle and organic EL light emitting cells of organic EL, respectively.

1A and 1B, an organic EL display device is a display device for electrically exciting a fluorescent organic compound to emit light, and is capable of representing an image by driving N × M organic light emitting cells by voltage driving or current driving. As shown in FIG. 1A, the organic light emitting cell structure has a structure of an ITO, an organic thin film, and a metal layer, and the organic thin film has a light emitting layer (Emitting Layer) in order to improve electron and hole balance and improve luminous efficiency. EML), Electron Transport Layer (ETL), and Hole Transport Layer (HTL), including a multi-layer structure, and also a separate Electron Injecting Layer (EIL) and hole injection layer (Hole) Injecting Layer (HIL). In addition, as shown in FIG. 1B, in the case of a top emission type organic EL light emitting cell, a metal anode, an organic thin film emission layer, and a transparent cathode may be formed on a silicon wafer.

As such a method of driving the organic light emitting cell, there are a simple matrix method and an active matrix method using a TFT. In the simple matrix method, the anode and the cathode are orthogonal and the line is selected and driven, whereas the active driving method is a driving method in which a TFT and a capacitor are connected to respective pixel electrodes to maintain a voltage by capacitor capacitance.

2 is a schematic block diagram of an organic EL display device.

Referring to FIG. 2, an organic EL display device may include a video controller 210, a panel controller 220, a power module 230, a scan driver 240, a data driver 250, and an organic EL panel 260. In this case, various signals passing through the analog interface and the digital interface are provided to the organic EL panel 260 in the column and row directions by the scan driver 240 and the data driver 250, respectively.

 Specifically, various analog signals such as R, G, B signals, and synchronization signals are input to the video controller 210 and then converted into digital signals, and the panel controller 220 controls them to sequentially scan the driver 240. ) And the data driver 250, the organic EL panel 260 may provide signals provided by the scan driver 240 and the data driver 250, and a power supply provided by the power supply module 230. Thus, the N × M organic light emitting cells are driven by voltage driving or current driving to express an image.

3 is a view showing a general organic EL display panel using an active driving method using a TFT thin film transistor.

Referring to FIG. 3, the organic EL display device includes an organic EL display panel 310, a data driver 320, and a scan driver 330.

The organic EL display panel 310 includes m data lines D1, D2, ..., Dm extending in the column direction, n scan lines S1, S2, ..., Sn extending in the row direction, and N x M Pixel circuits. The m data lines D1, D2, ..., Dm transfer data signals representing an image signal to the pixel circuits, and the n scan lines S1, S2, ..., Sn transfer respective selection signals to the pixel circuits. . Here, the pixel circuit is formed in one pixel region 310-1 defined by two neighboring data lines D1, D2,..., And Dm and two neighboring scan lines S1, S2,..., Sn. For example, the transistors 311 and 312, the capacitor 313, and the organic EL element 314 are formed. Here, reference numeral 315 denotes Vdd, which is a power supply voltage.

The scan driver 330 sequentially applies a selection signal to the n scan lines S1, S2,..., And Sn, and the data driver 320 images an image on m data lines D1, D2,..., And Dm. The data voltage corresponding to the signal is applied.

In addition, the scan driver 330 and / or the data driver 320 may be electrically connected to the organic EL display panel 310, or a tape carrier adhered to and electrically connected to the organic EL display panel 310. The package may be mounted in a chip carrier package (TCP). Alternatively, the display panel 310 may be mounted in a flexible printed circuit (FPC) or a film that is adhered to and electrically connected to the display panel 310 in the form of a chip.

The scan driver 330 and / or the data driver 320 may be directly mounted on the glass substrate of the organic EL display panel 310, or may be formed of the same layers as the scan line, the data line, and the thin film transistor on the glass substrate. It may be replaced with the driving circuit formed or may be directly mounted.

FIG. 4 is a diagram representatively showing one of N × M pixel circuits of the display panel of FIG. 3.

As shown in Fig. 4, the pixel circuit includes an organic EL element OLED, two transistors SM and DM and a capacitor Cst. For example, the two transistors SM and DM may be formed as PMOS transistors.

The driving transistor DM has a source connected to the power supply voltage Vdd, and a capacitor Cst connected between the gate and the source. The capacitor Cst maintains the gate-source voltage of the driving transistor DM for a period of time, and the switching transistor SM has a data voltage from the data line Dm in response to a selection signal from the current scan line Sn. Is transferred to the transistor DM.

The organic EL element OLED has a cathode connected to a reference voltage Vss and emits light corresponding to a current applied through the driving transistor DM. Here, the power source Vss connected to the cathode of the organic EL element OLED is a voltage having a lower level than the power source Vdd, and a ground voltage or the like may be used.

5 is a diagram illustrating an example of a demultiplexer of a light emitting display device according to the prior art, and FIG. 6 is a diagram illustrating a demultiplexer layout structure of the light emitting display device according to the prior art.

Referring to FIG. 5, the data driver 320 of the above-described light emitting display device may drive data of the red, green, and blue pixels by the demultiplexers De510 (510a, 510b). Apply a signal.

Each of the demultiplexers 510a and 510b includes shift registers 511 and 513, 512 and 514, and an analog switch, and the shift registers 511 and 513, 512 and 514 are input signals of the data driver 320. Levels are shifted and output, respectively, and the analog switch selects the shift registers 511 and 513, 512 and 514 according to respective selection signals.

Referring to FIG. 6, the conventional demultiplexers 510a, 510b, 520a, 520b, 530a, and 530b shift and output input signal levels with respect to each of the red, green, and blue signals, respectively. As shown, it is arranged in the transverse direction.

By the way, in the case of the demultiplexer of the light emitting display device according to the prior art, since it is arranged laterally with respect to the display panel when the demultiplexer layout which shifts and outputs the RGB data signal is output, it is arranged in accordance with the high resolution of the organic EL display panel. There is a problem that the lateral pitch may be insufficient.

SUMMARY OF THE INVENTION An object of the present invention for solving the above problems is to provide a multiplexer for shifting and outputting an input signal level for each RGB data in a data driver of a light emitting display device so as to arrange a layout so that a pitch is not insufficient. To provide a demultiplexer.

As a means for achieving the above object, the demultiplexer of the light emitting display device according to the present invention is connected to the data line, respectively, in the demultiplexer for selectively providing a data voltage transmitted to the pixel circuit of the light emitting display device according to a control signal; ,

A plurality of first, second, third, and fourth shift registers for shifting and outputting the input signal levels of the data driver for driving the red, green, and blue pixels, respectively; Shift register; And

A plurality of switches for selecting the plurality of shift registers according to respective selection signals

Including but not limited to:

Each of the plurality of shift registers may be arranged in a first direction for each group, using two as one group.

Wherein the switch is an analog switch selectively connected to the first, second, third and fourth shift registers respectively for the red, green and blue data inputs. do.

The first and third shift registers may be disposed on one side of the direction perpendicular to the first direction, and the second and fourth shift registers may be disposed on the other side of the direction perpendicular to the first direction. do.

According to the present invention, the layout pitch can be reduced by disposing the shift registers of the demultiplexer of the data driver of the light emitting display device in the vertical direction.

Hereinafter, a demultiplexer of a light emitting display device according to an embodiment of the present invention will be described in detail with reference to the accompanying drawings.

The circuit of the demultiplexer of the light emitting display device according to the embodiment of the present invention is the same as before, but the layout structure is changed to secure the layout pitch.

7 is a diagram illustrating a demultiplexer layout structure of a light emitting display device according to an exemplary embodiment of the present invention.

In the demultiplexer layout structure of the light emitting display device according to the present invention, the shift registers SH1, SH2, SH3, and SH4 are inputs of a data driver for driving currents of red, green, and blue pixels, respectively. The signal levels are shifted and output respectively.

As described above, referring back to FIG. 6, the data driver of the light emitting display device uses the demultiplexers 510a and 510b to drive the red, green, and blue pixels with current. (A1, A2, A3, A4 and B1, B2, S1, S2), wherein each of the demultiplexers 510a, 510b has shift registers 511, 513, 512, and 514, and an analog switch. Each of the shift registers 511, 513, 512, and 514 shifts and outputs an input signal level of the data driver, respectively, and the plurality of analog switches includes the plurality of shift registers 511, 513, 512, and 514. ) Is selected according to each selection signal.

In the demultiplexer 510a, 520a, 530a, 510b, 520b, and 530b layout structure of FIG. Paired in the vertical direction, as shown, the transverse pitch can be reduced by approximately half compared to FIG. 6 described above. Here, the transverse direction indicates the pitch direction, and the vertical direction means the direction perpendicular to the pitch.

Accordingly, the shift register includes first, second, third and fourth shift registers SH1, SH2, SH3, and SH4, and the shift registers SH1, SH2, SH3, and SH4 are vertical by two shift registers. Will be placed in the direction. That is, the first to fourth shift registers SH1, SH2, SH3, and SH4 respectively include the first and third shift registers SH1 and SH3 and the second and fourth shift registers SH2 and SH4, respectively. It is arranged in a vertical direction as a group.

In addition, the analog switch is selective with the first, second, third and fourth shift registers SH1, SH2, SH3, SH4 for the red, green, and blue data inputs, respectively. To be connected.

8 is a circuit diagram of a demultiplexer of a light emitting display device according to an exemplary embodiment of the present invention.

Referring to FIG. 8, a demultiplexer of a light emitting display device according to an exemplary embodiment of the present invention may include, for example, a first demultiplexer 510a including a first shift register SH1 511 and a third shift register SH3 513. The second to sixth demultiplexers 520a, 530a, 510b, 520b, and 530b are disposed in the transverse direction within the pitch intervals shown in the drawings, respectively, and the first shift register SH1 511 and the third shift are respectively arranged. The register SH3 513 and the second shift register SH2 512 and the fourth shift register SH4 514 are vertically disposed.

Here, the first shift register SH1 511 includes the PMOS transistors M2, M4 and M5 having their gates connected to the A1 signal line, the NMOS transistors M3 and M6 connected to the B1 signal line and their gates. A PMOS transistor M1 connected to the source / drain of the M2 transistor and its source / drain connected to the source / drain of the M4 transistor, and a capacitor C _hold that maintains a predetermined voltage value. The third shift register SH3 513 is symmetrical to each other except that an A3 signal line is connected instead of an A1 signal line of the first shift register SH1 511, and a B2 signal line is connected instead of the B1 signal line. Has a structural structure.

In addition, the second and fourth shift registers SH2 and SH4 are symmetrically with respect to the vertical structure of the first and third shift registers SH1 and SH3 and A-A 'shown in FIG. 7. Will be deployed.

FIG. 9 is a diagram illustrating an example of a demultiplexer layout structure according to the circuit of FIG. 8.

9 illustrates a layout structure of a first shift register SH1 511 in a demultiplexer of a light emitting display device according to an exemplary embodiment of the present invention, and each of the second to fourth shift registers 512, 513, and 514 may be described in detail. Only the connected signals are different and have substantially the same layout as the first shift register SH1 511. That is, two shift registers for each unit are arranged in the vertical direction, and arranged in six groups in the transverse direction within the pitch interval. That is, in the plurality of registers, the first and third shift registers are disposed in one vertical direction, and the second and fourth shift registers are disposed in the other vertical direction. 6 groups of demultiplexers can be arranged in the transverse direction, which are connected in correspondence with each of the < RTI ID = 0.0 > and < / RTI >

While the invention has been shown and described in connection with specific embodiments thereof, it will be appreciated that various modifications and changes can be made without departing from the spirit and scope of the invention as indicated by the claims. Anyone who owns it can easily find out.

 According to the present invention, in the data driver of the light emitting display device, by arranging shift shift registers for RGB of the demultiplexer vertically, the lateral pitch of the layout can be reduced, thereby ensuring the flexibility of layout design.

Claims (3)

A demultiplexer connected to a data line and selectively providing a data voltage transferred to a pixel circuit of a light emitting display device according to a control signal. A plurality of first, second, third, and fourth shift registers for shifting and outputting the input signal levels of the data driver for driving the red, green, and blue pixels, respectively; Shift register; And A plurality of switches for selecting the plurality of shift registers according to respective selection signals Including but not limited to: And each of the plurality of shift registers as one group, and arranged in a first direction for each group. The method of claim 1, Wherein said switch is an analog switch selectively connected with said first, second, third and fourth shift registers for said red, green and blue data inputs, respectively; Demultiplexer of display device. The method of claim 2, Wherein the first and third shift registers are disposed on one side of the direction perpendicular to the first direction, and the second and fourth shift registers are disposed on the other side of the direction perpendicular to the first direction. Demultiplexer of display device.

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