JP2004020704A - Display device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a display device in which the number of IC chips arranged on a transparent substrate can be decreased, the yield of production is improved, and the cost is reduced . <P>SOLUTION: One IC chip 20 drives a plurality of organic EL elements all together. The IC chip 20 is equipped with, for example, four pixel driving terminals. The number of IC chips 20 arranged on the transparent substrate 11 becomes small on the whole and the size of the IC chip 20 itself can be increased. The time needed to mount the IC chip 20 in a hollow 11A formed on the transparent substrate 11 is shortened. The number of data wires 34 and scanning wires 32 are decreased and the number of outputs of a driving circuit connected to those wires is decreased. <P>COPYRIGHT: (C)2004,JPO

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a display device in which an organic EL (Electro Luminescence) element or the like is formed as a pixel, and particularly to a display device having a driving element for controlling light emission of each pixel on the same substrate.
[0002]
[Prior art]
In the display device, for example, a large number of organic EL elements are arranged in a matrix as light emitting elements, and each of these organic EL elements constitutes one pixel. In this display device, an image or a character is displayed by selectively driving each pixel according to a video signal.
[0003]
As a driving method of the organic EL element provided in each pixel of such a display device, there is an active matrix method. This active matrix display device is provided with a drive element for controlling light emission for each organic EL element.
[0004]
Generally, a transistor such as a TFT (Thin Film Transistor) formed by directly performing a semiconductor process on a substrate is used as a driving element. On the other hand, in recent years, a technique has been proposed in which a block-shaped micro IC chip is used as a driving element, and the micro IC (Integrated Circuit) chip is disposed in a depression formed in a substrate. As a method of disposing the micro IC chip in the depression of the substrate, a silicon wafer on which many driving elements are formed is formed in a very small block shape so as to correspond to the number of pixels of the display device. After dividing into micro IC chips, there is a method in which these micro IC chips are disposed in depressions (see Japanese Patent Application Laid-Open No. 9-506742). The micro IC chip has a pair of opposed upper and lower surfaces, and the area of the upper surface is larger than that of the lower surface.
[0005]
FIG. 7 illustrates a configuration of the display device 100 to which the micro IC chip 120 is applied as a driving element. FIG. 8 illustrates the micro IC chip 120 in an enlarged manner. In the display device 100, a number of depressions 111A are formed in the transparent substrate 111, and a micro IC chip 120 is provided in each of these depressions 111A. Pixel drive terminals 125 are provided on the upper surface of the micro IC chip 120. Further, on the transparent substrate 111, the anode electrodes 141 driven through the pixel driving terminals 125 of the micro IC chip 120 are formed in a matrix.
[0006]
On the upper edge of the micro IC chip 120 in the X direction, in addition to the pixel driving terminals 125, a power supply terminal 121 connected to a power supply wiring 131, a scanning signal input terminal 122 connected to a scanning wiring 132, and a GND wiring A GND terminal 123 connected to the terminal 133 is provided. Further, a data signal terminal 124a and a data signal terminal 124b connected to the data wiring 134 are provided at each of a pair of opposed edges in the Y direction on the upper surface of the micro IC chip 120. Note that, in FIG. 7, a drive circuit connected to each of the data wiring 134 and the scanning wiring 132 and a configuration above the organic EL layer of the organic EL element are omitted.
[0007]
[Problems to be solved by the invention]
By the way, in the above-described display device 100, 2,359,296 pixels are required for performing high-definition display such as XGA display. However, since only one pixel drive terminal 125 is provided in the micro IC chip 120 shown in FIG. 8, only one pixel can be driven per micro IC chip 120. Therefore, a number corresponding to the number of pixels, that is, 2,359,296 micro IC chips 120 are required.
[0008]
As described above, in the conventional display device 100, since a large number of micro IC chips 120 must be provided on the transparent substrate 111 in accordance with the number of pixels, the size of the micro IC chip 120 is reduced, and In a process such as disposing in the depression 111A, the work becomes difficult. Further, since the connection pitch between each of the data wiring 134 and the scanning wiring 132 and the driving circuit becomes small, the wiring forming process becomes difficult, and as a result, there is a problem that the production yield is reduced.
[0009]
When the size of one microchip 120 is, for example, 80 μm, the area required to manufacture 2,359,296 micro IC chips 120 on a silicon wafer is about 15,000 mm ² , which is 120 mm ^2. This is equivalent to the area of the die, and the area of the die becomes very large. Further, the number of each of the data wiring 134 and the scanning wiring 132 increases, and the number of outputs of the driving circuit connected to these wirings also increases. As a result, there is a problem that the cost increases.
[0010]
The present invention has been made in view of such a problem, and an object of the present invention is to reduce the number of driving elements for driving a display element, improve the manufacturing yield, and reduce the cost. It is to provide a display device which can be used.
[0011]
[Means for Solving the Problems]
The display device according to the present invention includes a substrate, a plurality of display elements arranged in a matrix on the substrate and divided into a plurality of sets, and collectively driving each of the divided display elements for each set. A plurality of driving elements are provided, and a plurality of display elements are collectively driven by one driving element.
[0012]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.
[0013]
FIG. 1 shows a configuration of a display device 10 according to one embodiment of the present invention. The display device 10 has, for example, an organic EL element 40 as a display element. The organic EL element 40 is provided on the transparent substrate 11. FIG. 2 illustrates a configuration of the transparent substrate 11 on which the micro IC chip 20 (hereinafter, referred to as an IC chip 20) is provided. FIG. 3 is an enlarged view of the IC chip 20.
[0014]
The display device 10 includes a transparent substrate 11 made of, for example, plastic. The transparent substrate 11 is provided with a plurality of depressions 11A at regular intervals of, for example, several tens μm in each of the Y direction and the X direction. ing. Here, the plurality of dents 11A are formed at a double pitch in each of the Y direction and the X direction as compared with the related art, and the number of these dents 11A as a whole is one fourth of that of the related art. I have.
[0015]
In the recess 11A, an IC chip 20 is provided as a driving element for the organic EL element 40. The IC chip 20 is, for example, a silicon wafer on which a plurality of driving elements are formed, divided into blocks each having an upper surface and a lower surface. In the IC chip 20, the area of the upper surface is larger than that of the lower surface, and the size of the upper surface is about 80 μm.
[0016]
On the upper surface of the IC chip 20, pixel driving terminals 25a to 25d are provided at each of four corners on the upper surface of the IC chip 20. On the upper surface of the IC chip 20, between the pixel driving terminals 25a and 25c of the edge in the X direction, a power supply terminal 21 for supplying power from the outside, a scanning signal input terminal 22 for inputting a scanning signal, And the GND terminal 23 are provided. Further, on the upper surface of the IC chip 20, a data signal input terminal 24a and a data signal input terminal 24b are provided at each of a pair of opposed edges in the Y direction.
[0017]
In the IC chip 20, an analog data signal voltage is input from the data signal input terminal 24a, the data signal at the timing selected by the scanning signal input terminal 22 is held, and the data signal voltage is output from each of the pixel drive terminals 25a to 25d. The voltage-current conversion is performed so that a data current proportional to the current flows through each organic EL element 40.
[0018]
Wirings formed in the Y and X directions are electrically connected to each terminal of the IC chip 20. For example, in the Y direction, a power supply wiring 31 is provided for the power supply terminal 21 of the IC chip 20, a scanning wiring (Raw) electrode 32 is provided for the scanning signal input terminal 22, and a GND wiring 33 is provided for the GND terminal 23. Is connected. Further, in the X direction, the data wiring 34 (column (Column) electrode) is connected to the data signal input terminal 24a and the data signal input terminal 24b. The data wiring 34 is connected to each of the data signal input terminal 24a and the data signal input terminal 24b so that it does not cross each wiring in the Y direction. Note that the scanning wiring 32 formed in the Y direction is electrically connected to a row electrode drive circuit (not shown) provided at the edge of the transparent substrate 11 in the X direction. Further, the data wiring 34 formed in the X direction is electrically connected to a column electrode driving circuit (not shown) provided on the edge of the transparent substrate 11 in the Y direction.
[0019]
A large number of anode electrodes 41 made of, for example, indium tin oxide (ITO) are formed in a matrix so as to avoid each of the wires formed in the Y direction and the wires formed in the X direction. . These anode electrodes 41 are electrically connected to one of the pixel drive terminals 25a to 25d of the IC chip 20, respectively. Specifically, each of the anode electrodes 41a to 41d is connected to the pixel drive terminals 25a to 25d of the IC chip 20 surrounded by the anode electrodes 41a to 41d. Here, the number of each wiring in the Y direction and the X direction is half that of the conventional wiring.
[0020]
An insulating film (not shown) is formed in a region where the anode electrode 41 is not formed. An organic EL layer 42 is formed on the anode electrode 41 and the insulating film. Note that the organic EL layer 42 includes an organic hole transport layer in which holes are transported, an organic light emitting layer in which electrons and holes are recombined to emit white fluorescence, and an electron transport layer in which electrons are transported. It has a configuration in which the layers are sequentially stacked. A cathode electrode 43 made of a metal such as aluminum (Al) is formed on the organic EL layer 42 so as to face the anode electrode 41.
[0021]
An organic EL element 40 is constituted by the anode electrode 41, the organic EL layer 42, and the cathode electrode 43, and the organic EL element 40 constitutes a display panel. Note that one organic EL element 40 is formed corresponding to the formation region of one anode electrode 41, and one pixel is constituted by the organic EL element 40.
[0022]
In the present embodiment, one IC chip 20 is provided with four pixel drive terminals 25a to 25d, and a large number of organic EL elements 40 are divided into a plurality of sets corresponding to the number of IC chips 20. Pixel driving terminals 25a to 25d are individually connected to one set of organic EL elements 40, that is, four organic EL elements 40 surrounding one IC chip 20. As a result, the number of IC chips 20 is reduced to one fourth as compared with the conventional case, and the area of the die is reduced. Further, an IC chip 20 having a larger size than that of the related art can be provided on the transparent substrate 11. Further, the number of wirings in the Y direction and the X direction is one half of that in the related art, so that the area of the pixel is increased. In addition, the number of outputs of the drive circuit connected to these wirings is reduced. Further, the connection pitch between these wirings and the driving circuit can be increased.
[0023]
Next, a method for manufacturing the display device 10 having such a configuration will be described with reference to FIG. 4 and FIGS.
[0024]
First, a plurality of dents 11A having an upper surface and a lower surface and having a size of several tens of μm are formed at equal intervals in the X direction and the Y direction on the transparent substrate 11 by embossing, respectively. . The upper surface of the depression 11A is larger than the area of the lower surface. Subsequently, as shown in FIG. 4, the IC chip 20 is fitted into each of the plurality of recesses 11A and fixed using the self-assembly method. At this time, since the number of IC chips 20 mounted on the transparent substrate 11 is smaller than in the conventional case, the mounting time of the IC chips 20 is reduced. In addition, the size of the IC chip 20 can be increased, which facilitates the mounting of the IC chip 20 in the recess 11A.
[0025]
Here, these IC chips 20 are manufactured by dividing the silicon wafer on which the driving elements are formed into blocks so as to have a number corresponding to the number of the depressions 11A of the display device 10. At this time, pixel drive terminals 25a to 25d are provided on the upper surface of the IC chip 20 at each of the four corners on the upper surface of the IC chip 20. On the upper surface of the IC chip 20, a power supply terminal 21 to which power is supplied from the outside, a scanning signal input terminal 22 to which a scanning signal is input, and a GND terminal 23 between the pixel driving terminals 25 a and 25 c among the edges in the X direction Are provided. Further, on the upper surface of the IC chip 20, a data signal input terminal 24a and a data signal input terminal 24b are provided at each of a pair of opposed edges in the Y direction.
[0026]
Next, by using a photolithography method or a printing method, each wiring is formed in the Y direction and the X direction of the transparent substrate 11 so as to be electrically connected to each terminal of the IC chip 20.
[0027]
Specifically, in the Y direction, a power supply line 31 connected to the power supply terminal 21 of the IC chip 20, a scan line 32 connected to the scan signal input terminal 22, and a GND line 33 connected to the GND terminal 23 are formed. I do. Further, in the X direction, a data wiring 34 connected to the data signal input terminal 24a and the data signal input terminal 24b of the IC chip 20 is formed. The data wiring 34 is connected to each of the data signal input terminal 24a and the data signal input terminal 24b so as not to cross each wiring in the Y direction. At this time, the number of the data lines 34 and the number of the scan lines 32 formed on the transparent substrate 11 is reduced, so that the number of output lines of the drive circuits connected to these lines is reduced. Can be increased.
[0028]
Subsequently, a large number of anode electrodes made of, for example, indium tin oxide are formed on the transparent substrate 11 by sputtering so as to avoid the wirings formed in the Y direction and the wirings formed in the X direction. 41 are formed in a matrix. These anode electrodes 41 are formed so as to be electrically connected to one of the pixel drive terminals 25a to 25d of the IC chip 20.
[0029]
Next, an insulating film (not shown) is formed in a region where the anode electrode 41 is not formed. After the formation of the insulating film, the organic EL layer 42 is formed on the anode electrode 41 and the insulating film by using a vapor deposition method, a printing method, a spin coating method, or the like. The organic EL layer 42 includes an organic hole transport layer in which holes are transported, an organic light emitting layer in which electrons and holes are recombined to emit white fluorescence, and an electron transport layer in which electrons are transported. It has a configuration in which the layers are sequentially stacked. Finally, a cathode electrode 43 is formed on the organic EL layer 42 so as to face the anode electrode 41. The cathode electrode 43 is made of, for example, a metal such as aluminum. As described above, the display device 10 shown in FIG. 1 is manufactured.
[0030]
Next, an operation and a driving method of the display device 10 will be described with reference to FIGS. FIG. 5 schematically illustrates a part of the display device 10 according to the present embodiment. Each of the positions of a large number of pixels formed in a matrix is represented by, for example, (1, 1). It is represented by (x, y) coordinates. (1,1) is a sub-pixel.
[0031]
In the conventional display device 100, one pixel is electrically connected to one IC chip 120 as shown in FIG. In such a driving method of the display device 100, as shown in FIG. 10A, an analog data signal is transmitted through the data line 134A in the X direction at (1, 1), (2, 1),.・ Sent continuously as in. In each of the data wirings 134B to 134D, analog data signals are continuously transmitted in the X direction similarly to the data wiring 134A (FIGS. 10B, 10C, and 10D).
[0032]
At this time, as shown in FIG. 10E, the latch pulse causes the analog data signal continuously sent to the data wiring 134A through the scanning wiring 132A to be (1, 1), (1, 2),. Scanning is performed sequentially at a timing such that it is taken in each pixel. Also, in each of the scanning lines 132B to 132D, similarly to the scanning line 132A, the latch pulse is continuously transmitted in the Y direction (FIGS. 10F, 10G, and 10H). Thus, the data signal latched by the latch pulse of each scanning line is sent to the pixel drive terminal 125 provided on the IC chip 120.
[0033]
On the other hand, in the display device 10 of the present embodiment, as shown in FIG. 5, one IC chip 20 includes one set of pixels, that is, four pixels surrounding one IC chip 20. Connected. In such a driving method of the display device 10, in each data wiring, the frequency of the analog data signal is twice as high as the frequency of one data wiring in the conventional method, and the data wiring of two data wirings in the conventional method is used. Analog data signals are mixed and input to one data line. On the other hand, in each scanning line, a latch pulse of four scanning lines in the conventional method is input to one scanning line.
[0034]
Specifically, as shown in FIG. 6A, the analog data signal is transmitted through the data wiring 34A in the X direction at (1, 1), (1, 2), (2, 1), (2, 1). 2) Sent continuously as in. Also, analog data signals are continuously transmitted in the X direction on the data wiring 34B, similarly to the data wiring 34A (FIG. 6B). At this time, as shown in FIG. 6C, the latch pulse causes the analog data signal continuously transmitted to the data wiring 34A via the scanning wiring 32A to be (1, 1), (1, 2), ( .. Are sequentially scanned at timings to be taken in each pixel of (2, 1), (2, 2),. Also, in the scanning wiring 32B, similarly to the scanning wiring 32A, the latch pulse is continuously transmitted in the Y direction (FIG. 6D).
[0035]
In the display device 10 of the present embodiment, the analog data signals continuously transmitted to the data wirings 34A and 34B are latched by the scanning wirings 32A and 32B, respectively, and the latched data signal is output to one IC chip. The signal is sent to each of the four pixel driving terminals 25a to 25d provided in the pixel 20. At this time, in the IC chip 20, the data signals sent to each of the pixel drive terminals 25a to 25d are subjected to voltage-current conversion such that a data current proportional to these data signals flows to each pixel. As a result, a current is supplied to the organic EL element 40 disposed in each pixel, and the organic EL layer 42 of the organic EL element 40 emits light. The emitted light is transmitted through the transparent substrate 11 to display an image.
[0036]
As described above, according to the present embodiment, the four organic EL elements 40 are collectively driven by one IC chip 20, so that the number of IC chips 20 can be reduced as a whole. Therefore, it is possible to increase the size of the IC chip 20, thereby reducing the time for mounting the IC chip 20 in the recess 11A formed in the transparent substrate 11. Further, the area of the die can be reduced. Further, the number of the data wirings 34 and the number of the scanning wirings 32 can be reduced, and the number of output of the driving circuit connected to these wirings can be reduced. In addition, the connection pitch between these wirings and the driving circuit can be increased. As a result, the production yield can be improved, and the cost can be reduced.
[0037]
As described above, the present invention has been described with reference to the embodiment. However, the present invention is not limited to the above embodiment, and various modifications are possible. For example, in the above-described embodiment, four organic EL elements 40 are collectively driven by one IC chip 20, but the number is not limited, and for example, two organic EL elements are used. They may be driven collectively. Further, the display element is not limited to the organic EL element, and other elements, for example, a liquid crystal element or an LED (Light Emitting Diode) element may be applied.
[0038]
【The invention's effect】
As described above, according to the display device of the present invention, a plurality of display elements are collectively driven by one drive element, so that the number of drive elements can be reduced as a whole. Therefore, it is possible to increase the size of the driving element, thereby shortening the operation time such as the mounting time of the driving element in the depression formed in the substrate. Also, the area of the die can be reduced. Further, the number of data wirings and the number of scanning wirings can be reduced, and the number of outputs of a driving circuit connected to these wirings can be reduced. In addition, the connection pitch between these wirings and the driving circuit can be increased. As a result, the manufacturing yield can be improved and the cost can be reduced.
[Brief description of the drawings]
FIG. 1 is a schematic configuration diagram of a display device according to an embodiment of the present invention.
FIG. 2 is a schematic configuration diagram of a transparent substrate on which an IC chip of the display device shown in FIG. 1 is provided.
FIG. 3 is a schematic configuration diagram of an IC chip of the display device shown in FIG.
FIG. 4 is a process chart for explaining a method of manufacturing the display device shown in FIG.
FIG. 5 is a schematic diagram of a display device for explaining a driving method of the display device shown in FIG. 1;
FIG. 6 is a time chart for explaining a driving method of the display device shown in FIG. 1;
FIG. 7 is a schematic configuration diagram of a transparent substrate provided with a micro IC chip of a conventional display device.
8 is a schematic configuration diagram of a micro IC chip of the display device shown in FIG.
FIG. 9 is a schematic diagram of a display device for explaining a driving method of a conventional display device. FIG. 10 is a time chart diagram for explaining a driving method of a conventional display device.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 10 ... Display apparatus, 11 ... Transparent substrate, 11A ... Depression, 20 ... IC chip, 21 ... Power supply terminal, 22 ... Scan signal input terminal, 23 ... GND terminal, 24a, 24b ... data signal input terminals, 25a, 25b, 25c, 25d ... pixel drive terminals, 31 ... power supply wiring, 32 ... scanning wiring, 33 ... GND wiring, 34 ... Data wiring, 40 ... Organic EL element, 41 ... Anode electrode, 42 ... Organic EL layer, 43 ... Cathode electrode

Claims (8)

Board and
A number of display elements arranged in a matrix on the substrate and divided into a plurality of sets,
A display device, comprising: a plurality of driving elements each of which drives the divided display elements collectively for each set. The display device according to claim 1, wherein the driving element has a plurality of driving terminals, and individually drives different display elements through each driving terminal. 3. The display device according to claim 2, wherein the driving elements have the same number of driving terminals as the number of display elements in each set. The display device according to claim 1, wherein the driving element is an IC chip. The display device according to claim 1, wherein the display element is an organic EL element. 5. The display device according to claim 4, wherein the IC chip has a pair of opposed upper and lower surfaces, and the upper surface has a larger area than the lower surface. The display device according to claim 6, wherein a plurality of depressions are formed in the substrate, and the IC chip is provided in the depressions. The display device according to claim 1, wherein the substrate is a transparent substrate.

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