JP2009093063A - Current drive type device and display device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a display device the frame size of which can be reduced by efficiently disposing wiring, a circuit, and so on. <P>SOLUTION: The current drive type device has on its substrate: a first area in which a plurality of components are arranged, each component having a current drive type element and an element control circuit for controlling current caused to flow in a current drive type element; common wiring disposed around the first area so as to be apart from the first area; a second area between the first area and the common wiring; and a scanning line driver that outputs a scanning signal to be supplied to the element control circuit. The current drive type element is disposed between the first and second electrodes that are below and upper the substrate. The first electrode is electrically connected to the element control circuit, and the second electrode is electrically connected to the common wiring via a common electrode and a contact hole. The scanning line driver is composed of the first and second circuits, and the first circuit is disposed in the second area. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a current-driven device, a display device, and a camera having a region where a plurality of components are arranged on a substrate. The component includes a current-driven element and an element control circuit that controls a current flowing through the current-driven element. The present invention is suitably used for a display device using an electroluminescence element (hereinafter referred to as “EL element”) that emits light when a current is injected.

  In recent years, self-luminous display devices using light-emitting elements have attracted attention as next-generation display devices. Among them, a display device using an organic EL element which is a current-controlled light emitting element, that is, an organic EL display device is known. Organic EL display devices include an active matrix type using thin film transistors (TFTs) for pixel circuits and peripheral circuits in a display region. Therefore, in an organic EL display device, it is required to efficiently lay out power supply wiring and peripheral circuits in order to reduce the frame area in order to reduce the size and size of the display panel.

  As an example of the layout of the organic EL display device, it is described that a contact hole is provided at a corner of a rectangular common electrode commonly connected to the cathode side of the organic EL element and connected to the common wiring, and the common wiring is connected to an external terminal. There exists in patent document 1. FIG.

Patent Document 2 discloses an organic EL panel having an arrangement in which a part of a column signal output circuit among peripheral pixels is provided inside a contact hole.
JP 2001-109395 A (US Pat. No. 6,690,110) JP 2007-139966 A

  As disclosed in Patent Document 1, the scanning line driver and the data line driver, which are peripheral circuits, are arranged outside the common wiring, and thus the frame area is large. If the frame size is reduced, the device incorporating the display device can be downsized. Also, if the frame size is reduced, it may be aesthetically pleasing. Since the size of the frame is in the range of several millimeters from the edge of the glass substrate, the reduction effect is large even when the reduction is several hundred μm. In order to reduce the frame size, it is necessary to make the peripheral circuits finer, but there are limits to the fineness in manufacturing such as alignment accuracy and processing accuracy.

  Therefore, an object of the present invention is to provide a display device in which the frame size is reduced by efficiently arranging wirings, circuits, and the like.

  According to a first aspect of the present invention, a first region in which a plurality of components each including a current-driven element and an element control circuit that controls a current flowing through the current-driven element are arranged on a substrate; A common wiring disposed around the first region and spaced apart from the first region, a second region between the first region and the common wiring, and the element control circuit A scanning line driver that outputs a scanning signal to be provided, wherein the current-driven element is provided between a lower first electrode and an upper second electrode with respect to the substrate, and the first electrode A current-driven device electrically connected to an element control circuit, wherein the second electrode is electrically connected to the common wiring through a common electrode and a contact hole, wherein the scanning line driver is a first circuit; And the second circuit, and the first circuit is arranged in the second region. Current-driven apparatus characterized by being is provided.

  In the current-driven device according to the first aspect of the present invention, the scanning line driver may include an output buffer unit and a scanning signal generation unit, and the first circuit may include at least a part of the output buffer circuit.

  In the current-driven device according to the first aspect of the present invention, the output buffer unit may include one or more inverter circuits.

  In the current-driven device according to the first aspect of the present invention, the common wiring may be arranged so as to surround the first region.

  In the current-driven device according to the first aspect of the present invention, a terminal portion for electrically connecting to the outside is provided on the lateral side of the substrate, and the scanning is performed on the opposite side across the terminal portion and the first region. A line driver may be arranged.

  In the current drive device according to the first aspect of the present invention, the element control circuit may include at least one transistor.

    In the current-driven device according to the first aspect of the present invention, the scanning line driver may include a logic circuit and at least a shift register.

  According to a second aspect of the present invention, there is provided a display device using the current driven type device according to the first aspect of the present invention, wherein the current driven type element is a light emitting element. Provided.

  In the display device according to the second aspect of the present invention, the light emitting element may be an electroluminescence element.

  According to a third aspect of the present invention, there is provided a display device according to the second aspect of the present invention, an imaging unit that images a subject, and a video signal processing circuit that processes a signal imaged by the imaging unit. There is provided a camera for displaying the video signal processed by the video signal processing circuit on the display device.

  According to the present invention, a region including a plurality of components each including a current-driven element and an element control circuit that controls a current flowing through the current-driven element and a common wiring disposed around the region are provided. A part of the scanning line driver is arranged between them. Therefore, the frame size on the side where the scanning line driver on the substrate is arranged can be reduced. Thus, in order to reduce the weight and size of the device, it is possible to provide a display device in which wiring, peripheral circuits, and the like can be laid out efficiently and the frame size is reduced.

  The best mode for carrying out the present invention will be described below in detail with reference to the drawings.

  In the current drive type device of the present invention, the current drive type element may be a functional element provided between the lower first electrode and the upper second electrode. Examples of such a functional element include a light emitting element and a heating element (resistive element). In particular, an EL element typified by an organic EL element (which becomes a current-driven light-emitting element) is preferably used as the current-driven element.

  A display device can be configured by arranging one-dimensionally or two-dimensionally components that combine a current-driven light-emitting element and a switch element.

  Examples of the display device include a linear display device that displays image information, an active matrix display device, and the like. A linear display device showing image information can be combined with a photosensitive member as a scanner to constitute an image recording apparatus such as an optical printer or a copying machine. The active matrix display device can be used for a viewer used in a flat-screen television, a digital camera, a digital video camera, and a display unit of a mobile phone.

  It is necessary to provide a space between the common wiring and the region where a plurality of components in which current-driven light emitting elements and switch elements are combined are arranged. By arranging the drive circuit in this space, the layout can be efficiently performed.

  The best mode for carrying out the present invention is an active matrix display device using an EL element typified by an organic EL element. Hereinafter, embodiments of an active matrix display device using an EL element according to the present invention will be described with reference to the drawings.

  FIG. 1 is a schematic layout diagram of a display device according to the present embodiment.

  In FIG. 1, an image display unit 2 (first region) is disposed on a substrate 1, and the image display unit 2 controls an organic EL element having the number of RGB primary colors and a current input to the organic EL element. A pixel circuit composed of TFTs constitutes a pixel and is arranged two-dimensionally. The common wiring 3 is arranged so as to surround the entire periphery of the image display unit 2. In the pixel circuit, the organic EL element is disposed in an upper layer of the TFT and the storage capacitor. Although not shown in FIG. 1, a common electrode is arranged on the upper layer of the image display unit 2 and the common wiring 3 so as to cover the image display unit 2, the common wiring 3, and a gap between them. The common electrode is a transparent conductive plate. In the pixel display unit 2, the cathode of the organic EL element is directly and mechanically connected to the common electrode. In the common wiring 3, the common wiring 3 and the common electrode are mechanically and electrically connected through a large number of contact holes. The common wiring 3 is a conductor having a low resistance value and is grounded. By doing so, the resistance value between the cathode of the organic EL element and the ground can be lowered as compared with the case where there is no common wiring 3 and the common electrode is grounded at only one place. As the best mode for carrying out the present invention, the common wiring 3 is arranged on the entire circumference of the image display unit 2 like a “B” shape, but this is not always necessary. As described above, there may be a side where the common wiring 3 is not arranged among the four sides of the image display unit 2. The substrate 1 includes a scanning line driver 4 that outputs scanning signals and a data line driver 5 that outputs data signals. The terminal unit 6 supplies power to the display device and inputs control signals to the scanning line driver 4 and the data line driver 5. However, a power supply line and a control signal line connected to the terminal unit 6 are not shown. The position of the terminal portion 6 is arranged on the horizontal side of the substrate 1. In this case, the position of the scanning line driver 4 is arranged on the opposite side across the image display unit 2 as shown in FIG. Layout efficiency is good.

  The image display unit 2 and the common wiring 3 are arranged at a certain distance. That is, the image display unit 2 and the common wiring 3 are arranged apart from each other. Therefore, the second area occupies between the image display unit 2 and the common wiring 3. One reason for this is to secure an alignment margin in the organic EL device manufacturing apparatus. The organic EL element has organic layers such as a light-emitting layer, a hole transport layer, an electron transport layer, a hole injection layer, and an electron injection layer, and is stacked by vapor deposition in this embodiment mode. Each layer is patterned using a mask microfabricated into a desired pattern. When the organic EL element is vapor-deposited and the position of the mask is shifted and any of the organic layers as an insulator is vapor-deposited on the common wiring 3, the common electrode and the common wiring 3 cannot be connected. Therefore, the image display unit 2 and the common wiring 3 are arranged at a certain distance in order to secure a margin due to the alignment accuracy of the manufacturing apparatus.

  Another reason is a reduction in the influence of heat generated by the current flowing from the organic EL element during pixel light emission. Since all the current flowing from the organic EL element passes through the common wiring 3, heat is generated by the contact resistance between the common electrode and the common wiring 3 and the resistance of the common wiring 3 itself. Therefore, since the temperature around the common wiring 3 may increase and affect the characteristics of the organic EL element, it is desirable that the image display unit 2 and the common wiring 3 be spaced apart from each other.

  The scanning line driver 4 in the present embodiment includes an output buffer unit 4A and a scanning signal generation unit 4B, and the output buffer unit 4A is disposed between the image display unit 2 and the common wiring 3. The scanning signal generation unit 4 </ b> B and the data line driver 5 are disposed outside the common wiring 3.

  FIG. 2 shows a pixel circuit of the display device according to this embodiment. In FIG. 2, 7 is an organic EL element, 8 is a scanning line, and 9 is a data line. M1 is a TFT that is a switching transistor that controls the light emission of the element, M2 is a TFT that is a drive transistor that controls the light emission intensity of the element, and C1 is a storage capacitor for holding the light emission of the organic EL element 7. These TFTs and storage capacitors constitute an element control circuit. VCC represents the power supply potential, CGND represents the ground potential, and A and K represent the anode and cathode of the organic EL element, respectively.

  The anode A of the organic EL element is connected to the power supply potential VCC via the drive transistor M2, and the cathode K is connected to the ground potential CGND. The organic EL element 7 emits light when current flows from the power supply potential VCC through the driving transistor M2 and the organic EL element 7 to the ground potential CGND according to the gate potential of the driving transistor M2.

  In the present embodiment, the cathode K is a common electrode commonly connected to all the pixels, and is connected to the common wiring 3 in FIG. 1 through a contact hole.

  In the present embodiment, the pixel circuit has a configuration as shown in FIG. 2, but the present invention is not limited to the pixel circuit shown in FIG. 2 and may be another pixel circuit. For example, it may be a pixel circuit in which the anode A of the organic EL element is a common electrode, or may have a configuration having three TFTs or a configuration having four TFTs. The pixel circuit in FIG. 2 is a so-called voltage programming system circuit, but may not be a voltage programming system, but may be a so-called current programming system circuit. Note that a display device that emits light from an organic EL element is a current-driven device regardless of whether it is a voltage programming method or a current programming method. In the example of FIG. 2, a current determined by applying a voltage held by the holding capacitor C1 between the source and gate of the transistor M2 is caused to flow into the organic EL element, and in the sense that the emission luminance depends on the amount of the injected current. The device is a current driven device.

  FIG. 3 shows a circuit configuration of the scanning line driver 4 that outputs a scanning signal to the scanning lines 8 of the pixel circuit shown in FIG. A shift register 42 is provided, and at least as many output stages as the number of rows of the image display unit 2 are provided. Each output of the shift register 42 is output to the scanning line 8 via the output buffer circuit 41. The output buffer circuit 4A of FIG. 1 is configured by the plurality of output buffer circuits 41, and the scanning signal generation unit 4B is configured by the shift register. In addition, a logic circuit including a NOT gate, an AND gate, an OR gate, and the like may be included.

  FIG. 4 shows the circuit configuration of the output buffer circuit 41. The output buffer circuit 41 is formed by connecting two inverter circuits (INV1, INV2) composed of N-type TFTs (MN1, MN2) and P-type TFTs (MP1, MP2). The output from the shift register 42 is input to IN. OUT is connected to the scanning line 8. VCC is a power supply potential, and GND is a ground potential. By increasing the gate width of the TFT in the order of INV1 and INV2, the necessary driving capability is set to INV2, and the driving capability sufficient to drive the scanning line 8 is obtained. If the image display unit 2 becomes large or the number of pixel columns increases, the load on the scanning line 8 becomes large, so that the drive capability of the output buffer circuit 41 must be increased. As a result, the size of the inverter circuit increases and the output buffer circuit 41 becomes large. In this embodiment, the output buffer circuit 41 is composed of two inverter circuits. However, the present invention is not limited to this, and any number of inverter circuits may be used as long as the scanning lines 8 can be driven sufficiently. That is, the number of inverter circuits may be appropriately adjusted as long as it is one or more.

  In the present embodiment, the entire output buffer circuit 41 has been described as being disposed between the image display unit 2 and the common wiring 3. However, the output buffer circuit 41 is not necessarily disposed as such, and the inverter circuit INV1, INV2 includes INV2. Only the portion may be arranged. In addition to the output buffer circuit 41, a part of the shift register 42 may be disposed between the image display unit 2 and the common wiring 3. If the scanning line driver 4 has another logic circuit, the logic circuit may be disposed between the image display unit 2 and the common wiring 3. That is, the layout of the scanning line driver 4 can be divided into the first circuit and the second circuit in consideration of the arrangement space.

  In this way, the scanning line driver 4 is divided, and a part of the scanning line driver 4 is arranged in the space between the image display unit 2 and the common wiring 3, thereby improving the layout efficiency. The frame area on the side where 4 is arranged can be reduced.

  The display device of the embodiment described above can constitute an information display device. This information display device is a mobile phone, a mobile computer, a still camera, a video camera, or the like, or a device that realizes a plurality of these functions. The information display device includes an information input unit. For example, in the case of a mobile phone, the information input unit includes an antenna. In the case of a PDA or a portable personal computer, the information input unit includes an interface unit for the network. In the case of a still camera or a movie camera, the information input unit includes a sensor unit such as a CCD or CMOS.

  Next, as a preferred embodiment of the present invention, an example in which the display device according to the present invention is used in a digital still camera will be described.

  FIG. 5 is a block diagram of an example of a digital still camera using the display device according to the present invention. In the figure, 50 is a digital still camera system, 51 is a photographing unit, 52 is a video signal processing circuit, 53 is a display panel, 54 is a memory, 55 is a CPU, and 56 is an operation unit.

  In FIG. 5, a video that is a subject photographed by the imaging unit 51 or a video recorded in the memory 54 can be signal-processed by the video signal processing circuit 52 and viewed on the display panel 53. The CPU 55 controls the photographing unit 51, the memory 54, the video signal processing circuit 52, and the like according to the input from the operation unit 56, and performs photographing, recording, reproduction, and display suitable for the situation. In addition, the display panel 53 can be used as a display unit of various electronic devices.

  In the current-driven device of the present invention, for example, an EL element typified by an organic EL element (which becomes a current-driven light-emitting element) can be used as the current-driven element, and a display device can be configured using these elements. it can.

It is a top view which shows the layout schematic of the display apparatus which concerns on this invention. It is a circuit diagram which shows the pixel circuit of the display apparatus which concerns on this invention. It is a circuit diagram which shows the scanning line driver of the display apparatus which concerns on this invention. FIG. 4 is a circuit diagram of an output buffer circuit of the scanning line driver shown in FIG. 3. It is a block diagram of an example of a digital still camera using a display device according to the present invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Board | substrate 2 Image display part 3 Common wiring 4 Scan line driver 4A Output buffer part 4B Scan signal generation part 5 Data line driver 6 Terminal part 7 Organic EL element 8 Scan line 9 Data line 41 Output buffer circuit 42 Shift register 50 Digital still camera System 51 Shooting unit 52 Video signal processing circuit 53 Display panel 54 Memory 55 CPU
56 Operation unit

Claims (10)

A first region in which a plurality of components including a current-driven element and an element control circuit for controlling a current flowing through the current-driven element are arranged on a substrate, and the first region around the first region. A scanning line driver that outputs a scanning signal to be supplied to the element control circuit, a common wiring that is spaced apart from one area, a second area between the first area and the common wiring, Have
The current-driven element is provided between a lower first electrode and an upper second electrode with respect to the substrate, the first electrode is electrically connected to the element control circuit, and the second electrode is A current driven device electrically connected to the common wiring via a common electrode and a contact hole,
The scan line driver includes a first circuit and a second circuit, and the first circuit is disposed in the second region.   The current-driven device according to claim 1, wherein the scanning line driver includes an output buffer unit and a scanning signal generation unit, and the first circuit includes at least a part of the output buffer circuit.   The current-driven device according to claim 1, wherein the output buffer unit includes one or more inverter circuits.   4. The current-driven device according to claim 1, wherein the common wiring is disposed so as to surround the first region. 5.   2. The scanning line driver according to claim 1, further comprising: a terminal portion electrically connected to the outside on a lateral side of the substrate, wherein the scanning line driver is disposed on the opposite side across the terminal portion and the first region. The current drive type device according to claim 1.   The current-driven device according to claim 1, wherein the element control circuit includes at least one transistor.   The current driving type device according to claim 1, wherein the scanning line driver includes a logic circuit and includes at least a shift register.   8. A display device using the current driven device according to claim 1, wherein the current driven device is a light emitting element.   The display device according to claim 8, wherein the light emitting element is an electroluminescence element.   A display device according to any one of claims 8 to 9, comprising: an imaging unit that images a subject; and a video signal processing circuit that processes a signal captured by the imaging unit; A camera for displaying a video signal signal-processed by a processing circuit on the display device.