JP4610886B2 - Image display device, electronic equipment - Google Patents

Description

The present invention relates to an image display device in which pixels are arranged in a matrix and an inspection method for the image display device.

  In image display devices such as a liquid crystal display (LCD) and an electroluminescence (EL) display, in recent years, high definition has been advanced and the integration degree of elements has been greatly improved.

  In the production line of image display devices, it is indispensable to inspect whether the circuit mounted on the board is operating normally when the panel is shipped as a finished product, but the inspection process itself is complicated due to the above-mentioned high definition. It is becoming.

  FIG. 3 shows a configuration of a substrate on which an inspection circuit is mounted in a conventional image display device (see, for example, Patent Document 1). This image display device includes a substrate 301, a source driving circuit 302, a gate driving circuit 303, a pixel 304, a data signal line 305, a scanning line 306, an inspection circuit 311, a switch driving circuit 312, an analog switch 313, an inspection line 314, and an inspection terminal. 315a and 315b. The substrate 301 has an inspection circuit 311 and has pixels 304 arranged in a matrix. Data signal lines (source bus lines) 305 and scanning lines (gate bus lines) 306 are arranged so as to be orthogonal to each other. The scanning line 306 is connected to the gate driving circuit 303, and each data signal line 305 is connected to the source driving circuit 302.

  The pixel portion includes a first pixel that is provided in the display region and contributes to display, and a second pixel that is provided in an outer edge portion of the display region (hereinafter referred to as a non-display region) and does not contribute to display. . An outline is shown in FIG. However, for the sake of simplicity, the non-display area is provided in the area indicated by 704b. However, the non-display area is usually provided so as to surround the outer edge of the display area.

  The display device controls each pixel connected to each scanning line 306 by each scanning line 306, and the video signal is sequentially taken into the source driving circuit 302, and each data signal is simultaneously input with the latch signal. The signal is output to the line 305 and input to each pixel.

  The pixel included in the display device will be described in detail with reference to FIG. Each pixel includes a data signal line 711, a scanning line 712, a current supply line 717, a switching thin film transistor (hereinafter referred to as a thin film transistor) 713, a driving TFT 714, a capacitor means 715, a light emitting element 716, and a power supply line 718. Have.

  A switching TFT 713 is connected between the gate electrode of the driving TFT 714 and the data signal line 711, and a scanning line 712 is connected to the gate electrode of the switching TFT 713. Therefore, when the switching TFT 713 is ON, the driving TFT 714 can be controlled by a signal output to the data signal line 711. The capacitor means 715 is located between the gate electrode of the driving TFT 714 and the current supply line 717 and holds the gate-source voltage of the driving TFT 714.

  The difference between the first and second pixels will be described below. In the first pixel, the light emitting element 716 is connected to the driving TFT 714 and the power supply line 718, and the driving TFT 714 emits light by supplying current from the current supply line 717 to the light emitting element 716. Light emission is performed according to the potential of the input video signal by sending a video signal from the source signal line to the gate electrode of the driving TFT. The second pixel does not emit light because the light emitting element and the driving TFT are not connected, and is a dummy pixel.

  One of the reasons for installing a non-display area having dummy pixels in the periphery of the display area in this way is to form a liquid crystal element or a light emitting element in a pixel portion in a flat panel display such as a display using an LCD or a light emitting element. In this case, the peripheral portion is likely to be inhomogeneous compared to the central portion of the pixel portion (for example, see Patent Document 2).

  Detection of a short circuit between wirings of the display device or disconnection of the wirings includes a method in which a probe pin is brought into contact with an inspection terminal 315 a provided at the end of the scanning line 306 to check an output, and a method in which an inspection circuit 311 is used. The inspection circuit 311 sequentially drives the switch control circuit 312 and sequentially sends the potential level of each data signal line to the inspection line 314, and contacts the inspection terminal 315b with the probe pin for inspection.

  When the method of bringing the probe pins into contact with the inspection terminals 315a is used, inspection is performed on the same number of inspection terminals as each inspection line, which requires enormous time. Alternatively, if the number of probe pins is increased in order to shorten the time, an expensive inspection machine is required. Therefore, it is conceivable to form the inspection circuit 311 on the substrate. However, since the switch driving circuit 312 is required, it occupies a huge area even though the circuit is irrelevant to the image display.

  On the other hand, an image display apparatus having an inspection circuit in which no switch drive circuit is installed has been proposed (see, for example, Patent Document 3). FIG. 4 is a configuration diagram of the image display device. The substrate 401, the source driving circuit 402, the gate driving circuit 403, the pixel 404, the data signal line 405, the scanning line 406, the video signal line 407, the analog switches 408 and 412, An inspection circuit 411, an inspection line 413, and inspection terminals 414a and 414b are provided. Each data signal line 405 is connected to the gate of the analog switch 412.

  When inspecting the data signal line 405, an inspection pulse is input to the video signal line 407, and the output waveform from the analog switch 412 is observed by the output of the inspection terminal 414b, so that a defect such as disconnection can be found. .

JP-A-14-116423 Japanese Patent Laid-Open No. 5-241153 Japanese Patent No. 2618042

  However, in the above inspection method, only the operation of the gate driving circuit 403 and the source driving circuit 402 and the quality of the scanning line 406 and the data signal line 405 are inspected. However, if the thin film transistor in the pixel 404 is sufficiently controlled, it cannot be said that the inspection is sufficient.

  The object of the present invention is that the inspection machine can perform inspection easily and in a short time while keeping the area of the inspection circuit to a minimum without using many probe pins. An object is to provide an image display device capable of inspecting not only the lines but also the characteristics of TFTs inside the pixel, and an inspection method for the image display device.

  In order to enable the inspection of the circuit in the pixel and the pixel control to be performed easily and reliably while minimizing the portion occupied by the inspection circuit, the present invention provides a part of the pixel circuit as an inspection circuit or The display device is a dummy circuit.

The image display device of the present invention includes:
A pixel portion provided with a display area and an inspection area;
Each of the display area and the inspection area includes a first pixel circuit and a second pixel circuit,
Each of the first pixel circuit and the second pixel circuit includes a data signal line, a scanning line, a switching transistor, and a driving transistor,
The switching transistor is provided between the data signal line and the gate electrode of the driving transistor with a gate electrode electrically connected to the scanning line,
In the first pixel circuit, the driving transistor is provided between a current supply line and a light emitting element,
In the second pixel circuit, the driving transistor is provided between the current supply line and a test output terminal.

The image display device of the present invention includes:
A pixel portion provided with a display area and an inspection area;
Each of the display area and the inspection area includes a first pixel circuit and a second pixel circuit,
The first pixel circuit includes a data signal line, a scanning line, a switching transistor, and a driving transistor,
The second pixel circuit includes the data signal line, the scanning line, and the switching transistor,
In the first pixel circuit, the switching transistor is provided between the data signal line and the gate electrode of the driving transistor with a gate electrode electrically connected to the scanning line, and the driving transistor Is provided between the current supply line and the light emitting element,
In the second pixel circuit, the switching transistor is provided between the data signal line and a test output terminal.

In the image display device of the present invention,
The inspection area is provided in a dummy pixel area provided in an outer edge portion of the display area portion.

The inspection method of the image display device of the present invention includes:
A pixel portion provided with a display area and an inspection area;
Each of the display area and the inspection area includes a first pixel circuit and a second pixel circuit,
Each of the first pixel circuit and the second pixel circuit includes a data signal line, a scanning line, a switching transistor, and a driving transistor,
The switching transistor is provided between the data signal line and the gate electrode of the driving transistor with a gate electrode electrically connected to the scanning line,
In the first pixel circuit, the driving transistor is provided between a current supply line and a light emitting element,
In the second pixel circuit, the driving transistor is provided between the current supply line and an inspection terminal,
With the scanning line selected, the switching transistor in the second pixel circuit is turned on, and the drain current of the driving transistor is output to the inspection terminal in accordance with the signal output to the data signal line. Features.

In the inspection method of the image display device of the present invention,
The signal output to the data signal line is a video signal.

In the inspection method of the image display device of the present invention,
The signal output to the data signal line is an inspection pulse.

The inspection method of the image display device of the present invention includes:
A pixel portion provided with a display area and an inspection area;
Each of the display area and the inspection area includes a first pixel circuit and a second pixel circuit,
The first pixel circuit includes a data signal line, a scanning line, a switching transistor, and a driving transistor,
The second pixel circuit includes the data signal line, the scanning line, and the switching transistor,
In the first pixel circuit, the switching transistor is provided between the data signal line and the gate electrode of the driving transistor with a gate electrode electrically connected to the scanning line, and the driving transistor Is provided between the current supply line and the light emitting element,
In the second pixel circuit, the switching transistor is provided between the data signal line and a test output terminal,
The scanning line is selected, the switching transistor in the second pixel circuit is turned on, and the signal output to the data signal line is output to the inspection output terminal.

According to the image display device and the inspection method of the present invention, by changing a part of the pixel circuit to form an inspection circuit or using a dummy pixel, the data signal line and the scanning are suppressed while minimizing the area occupied by the inspection circuit. Inspections such as wire breaks and pixel control inspections can be performed easily and reliably, and if there is an abnormality, the position can be known.

  The present invention will be described in detail by the following embodiments.

[Embodiment 1]
FIG. 1A shows an inspection circuit according to the first embodiment of the present invention. The inspection circuit includes a data signal line 101, a scanning line 102, a switching TFT 103, a driving TFT 104, a capacitor means 105, a current supply line 106, an inspection cell 107, and an inspection line 108. This circuit is created for the purpose of inspecting data signal lines. The inspection circuit is created based on the pixel circuit (FIG. 1B), and the inspection cell 107 in FIG. 1A corresponds to the pixel circuit. 1B includes a data signal line 111, a scanning line 112, a switching TFT 103, a driving TFT 104, a capacitor 105, an EL element 116, a current supply line 117, and a power supply line 118.

The pixel circuit emits light when the driving TFT 104 supplies current to the EL element 116. A video signal is sent from the source signal line 111 to the gate of the driving TFT 104 by the switching TFT 103, and light emission is performed according to the potential of the input video signal.

  The configuration of the inspection cell 107 will be described in comparison with a pixel circuit (FIG. 1B). First, the EL element 116 to which the driving TFT 104 supplies current is removed from the pixel circuit. Further, it is disconnected from the power supply line 118 connected to the EL element, and instead, the driving TFT 104 is connected to the inspection line 108. The inspection line 108 is connected to the inspection terminal. The scanning line 112 shared by the pixel circuits is separated from the gate drive circuit and is made independent as the inspection circuit switch signal line 102. In this way, the inspection cell 107 is configured. The driving TFT 104 plays a role as an analog switch controlled by a video signal when the switch signal line 102 is input and the switching TFT 103 is ON.

  The data signal line inspection will be described. An inspection circuit as shown in FIG. 1A is formed on the substrate. The inspection circuit connects n data signal lines connected to the pixel portion and S1, S2,..., Sn on a one-to-one basis. The potential of the video signal is output to each data signal line, and at this time, a switch signal is input. When the switching TFT 103 is ON, the switch control of the driving TFT 104 is performed by a video signal, which can be inspected by comparing the video signal with the measured output value OUT. By inputting the inspection pulse to the video signal, it becomes easy to identify the place where there is an abnormality.

  FIG. 5B shows a timing chart at the time of inspection. The substrate 501 shown in FIG. 5A has a structure in which video signals are sequentially taken into the first latch circuit by the shift register and are simultaneously output from the second latch circuit to each data signal line when the latch signal is high. It is. For this reason, as shown in FIG. 5C, n data signal lines S1, S2,..., Sn are selected one by one, and the video signal input period V is provided n times. When the latch signal is selected, the output signal at this time is a High output at the same time because the driving TFT in one inspection cell is in the ON state.

[Embodiment 2]
FIG. 2 shows an inspection circuit according to a second embodiment of the present invention. This circuit is created for the purpose of scanning line inspection. Like the first embodiment, the pixel circuit is created based on the pixel circuit in FIG. 1B, and the inspection cell 205 in FIG. 2A corresponds to the pixel circuit.

  The inspection circuit in FIG. 2A includes a scanning line 201, a switching TFT 202, a capacitor 203, a current supply line 204, an inspection cell 205, and an inspection line 206.

  The configuration of the inspection cell 205 will be described in comparison with a pixel circuit. The EL element and the driving TFT are removed from the pixel circuit. Further, the power supply line 118 connected to the EL element and the TFT 104 in the pixel are separated and connected to the inspection line 206. In addition, the test cell 205 is the data signal line 111 shared by the pixel circuit is disconnected from the source driving circuit and connected to the power supply voltage. The switching TFT plays a role as an analog switch controlled by a gate drive circuit.

  In the case where dummy pixels are provided in the periphery of the display region and the pixels have the same structure in order to make the film thickness of the EL uniform in the display region, if the driving TFT cannot be deleted, it may not be deleted. For the connection, the contact between the switching TFT, the driving TFT and the capacitor means is commonly connected to the inspection line and connected to the inspection terminal.

  The scanning line inspection will be described. An inspection circuit as shown in FIG. 2A is formed on the substrate, and the n scanning lines connected to the pixel portion and G1, G2,..., Gn are connected on a one-to-one basis. Signals are sequentially output from the gate drive circuit to the respective scanning lines 201, so that the switching TFTs 202 are sequentially turned on and can be inspected by measuring the output value OUT at this time.

  Unlike the data signal line, the scanning line cannot be input with the inspection pulse, so that the output unit needs to be devised. 2A has two outputs, OUT1 and OUT2, and by connecting the scanning lines alternately to OUT1 and OUT2, when the shift register sequentially selects the switching TFT 202, a square wave can be detected. The distinction becomes clear. FIG. 6B shows a timing chart. Each of the scanning lines G1, G2,..., Gn is sequentially turned on, and the output is alternately a High output. The advantage of outputting such a square wave is that an abnormal location can be identified by counting the number of the square waves.

As a countermeasure against the inability to input the inspection pulse, or as shown in FIG. 2B, by adding a delay buffer 211 and a NAND 212, the buffer creates a delay and performs a NAND operation on the output to generate a square wave. There is a method to detect.

  Examples of the present invention will be described below.

  FIG. 5A shows a first embodiment of the present invention. The display device shown here includes a substrate 501, a source driver circuit 502, a gate driver circuit 503, a pixel 504, a data signal line 505, and a scanning line 506. Of the pixels 504 arranged in a matrix, the last stage opposite to the source driver circuit 502 is selected as a row of pixels perpendicular to the data signal line. If dummy pixels are arranged in the periphery, the dummy pixels may be selected. The following changes are made to the selected pixel. The EL element is removed from the pixel, and the power supply line connected to the EL element and the TFT in the pixel are separated and connected to the inspection terminal instead. Of course, a plurality of inspection terminals may be provided for inspection reasons, but in the embodiment of FIG. 5A, the number of inspection terminals is reduced to one by connecting them in common. Next, the scanning line 506 shared by the pixels is disconnected from the gate driving circuit 503 and is made independent as a switch signal line. In this embodiment, the switch signal lines are made independent in order to simplify the inspection. However, if the switch signal lines are controlled by the gate drive circuit, they are not made independent and may remain connected. As shown in FIG. 5B, the data signal line is inspected by inputting inspection pulses S1, S2,..., Sn while the switch signal line is input, and outputting the latch signal as an output signal. Determine by observing.

  In this embodiment, the TFT in the pixel is used as it is, but the TFT size may be similarly changed for the purpose of increasing the sensitivity in order to confirm driving of the TFT inside the pixel.

 FIG. 6A shows a second embodiment of the present invention. The display device shown here includes a substrate 601, a source driver circuit 602, a gate driver circuit 603, a pixel 604, a data signal line 605, and a scanning line 606. Of the pixels 604 arranged in a matrix, the last stage facing the gate drive circuit 603 is selected as a row of pixels perpendicular to the scanning line. If dummy pixels are arranged in the periphery, the dummy pixels may be selected. The following changes are made to the selected pixel. The EL element and the driving TFT are removed from the pixel, and the power supply line connected to the EL element and the TFT in the pixel are separated and connected to the inspection line instead. In the embodiment of FIG. 6A, the scanning lines 606 are alternately connected with two outputs. Next, the data signal line 605 shared by the pixels is disconnected from the source driver circuit 602 and connected to the power supply voltage. In this embodiment, the power source voltage is connected to simplify the inspection. However, if the potential level detectable by the source driver circuit 602 can be given, the power source voltage may be left connected. As shown in FIG. 6B, the scanning line inspection method is determined by moving the gate driving circuit and observing the output signal.

In this embodiment, the TFT in the pixel is used as it is, but the TFT size may be similarly changed for the purpose of increasing the sensitivity in order to confirm driving of the TFT inside the pixel.

  In this embodiment, various electric appliances having the display device of the present invention will be described. The display device of the present invention can inspect the driving circuit, the scanning line, the data signal line, and the TFT characteristics inside the pixel easily and in a short time after the pixel and the wiring are formed. For this reason, it is possible to remove defective products before assembling the product, and as a result, the product can be manufactured efficiently and inexpensively.

  As an electric device created using the display device of the present invention, a video camera, a digital camera, a goggle type display (head mounted display), a navigation system, a notebook type personal computer, a game device, an information terminal form (mobile computer, mobile phone) , A portable game machine or an electronic book), an image playback device including a storage medium (specifically, a device including a display device capable of displaying a digital video disc (DVD)), and the like. Specific examples of these electric devices are shown in FIGS.

  FIG. 8A illustrates a display device, which includes a housing 801, a support base 802, a display portion 803, a speaker portion 804, a video input terminal 805, and the like. The display device of the present invention can be used for the display portion 803. The display device includes all information display devices such as a personal computer, a TV broadcast reception, and an advertisement display.

  FIG. 8B illustrates a laptop personal computer, which includes a main body 811, a housing 812, a display portion 813, a keyboard 814, an external connection port 815, a pointing mouse 816, and the like. The display device of the present invention can be used for the display portion 813.

  FIG. 8C illustrates a mobile computer, which includes a main body 821, a display portion 822, a switch 823, operation keys 824, an infrared port 825, a stylus 826, and the like. The display device of the present invention can be used for the display portion 822.

  FIG. 8D illustrates a portable image reproducing device (specifically, a DVD reproducing device) provided with a recording medium, which includes a main body 831, a housing 832, a display portion A 833, a display portion B 834, and a recording medium (DVD or the like). A reading unit 835, operation keys 836, a speaker unit 837, and the like are included. The display portion A833 mainly displays image information, and the display portion B834 mainly displays character information and information for operation. The display device of the present invention can be used for the display portions A and B 833 and 834. Note that the image reproducing device provided with the recording medium includes a home game machine and the like.

  FIG. 8E illustrates a goggle type display (head mounted display), which includes a main body 841, a display portion 842, an arm portion 843, and the like. The display device of the present invention can be used for the display portion 842.

  FIG. 8E illustrates a video camera, which includes a main body 851, a display portion 852, a housing 853, an external connection port 854, a remote control receiving portion 855, an image receiving portion 856, a battery 857, an audio input portion 858, operation keys 859, and an eyepiece. Part 860 and the like. It is created by using the display device of the present invention for the display portion 852.

  FIG. 8F illustrates a mobile phone, which includes a main body 861, a housing 862, a display portion 863, an audio input portion 864, an audio output portion 865, operation keys 866, an external connection port 867, an antenna 868, and the like. The display device of the present invention can be used for the display portion 863.

The figure which shows embodiment of this invention. The figure which shows embodiment of this invention. The figure which shows the structure of the board | substrate which mounted the test | inspection circuit in the conventional image display apparatus. The figure which shows the structure of the image display apparatus which has the conventional test | inspection circuit. The figure which shows the Example of this invention. The figure which shows the Example of this invention. The figure which shows the example of a structure of the conventional image display apparatus. FIG. 14 is a diagram showing an example of an electronic apparatus using the image display device of the present invention.

Claims (6)

It has a display area and an inspection area,
The display area includes a first pixel circuit,
The inspection area includes a second pixel circuit,
The first pixel circuit includes a first switching transistor, a first driving transistor, and a light emitting element,
The second pixel circuit includes a second switching transistor capacitor, the second driving transistor,
A gate of the first switching transistor is electrically connected to the first scanning line;
One of the source and the drain of the first switching transistor is electrically connected to the data signal line,
The other of the source and the drain of the first switching transistor is electrically connected to the gate of the first driving transistor,
A gate of the second switching transistor is electrically connected to a second scanning line;
One of the source and the drain of the second switching transistor is electrically connected to the data signal line,
The other of the source and the drain of the second switching transistor is electrically connected to the gate of the second driving transistor,
One of the source and the drain of the first driving transistor is electrically connected to a current supply line,
The other of the source and the drain of the first driving transistor is electrically connected to the light emitting element,
One of the source and the drain of the second driving transistor is electrically connected to the current supply line,
The other of the source and the drain of the second driving transistor is electrically connected to the inspection output terminal ,
A video signal is supplied to the data signal line, a switch signal is input to the second scanning line, and the data signal line is inspected by comparing the video signal with a signal output from the inspection output terminal. An image display device characterized by that. A display area, an inspection area, and a source drive circuit;
The display area includes a first pixel circuit,
The inspection area includes a second pixel circuit,
The first pixel circuit includes a first switching transistor, a first driving transistor, and a light emitting element,
The second pixel circuit includes a second switching transistor capacitor, the second driving transistor,
A gate of the first switching transistor is electrically connected to the first scanning line;
One of the source and the drain of the first switching transistor is electrically connected to the data signal line,
The other of the source and the drain of the first switching transistor is electrically connected to the gate of the first driving transistor,
A gate of the second switching transistor is electrically connected to a second scanning line;
One of the source and the drain of the second switching transistor is electrically connected to the data signal line,
The other of the source and the drain of the second switching transistor is electrically connected to the gate of the second driving transistor,
One of the source and the drain of the first driving transistor is electrically connected to a current supply line,
The other of the source and the drain of the first driving transistor is electrically connected to the light emitting element,
One of the source and the drain of the second driving transistor is electrically connected to the current supply line,
The other of the source and the drain of the second driving transistor is electrically connected to the inspection output terminal,
The source driving circuit is electrically connected to the data signal line;
A video signal is supplied from the source driving circuit to the data signal line, a switch signal is input to the second scanning line, and the data is compared by comparing the video signal with a signal output from the inspection output terminal. An image display device characterized by inspecting a signal line. In claim 1 or claim 2,
The image display device, wherein each of the first switching transistor, the first driving transistor, the second switching transistor, and the second driving transistor is a thin film transistor. In any one of Claims 1 thru | or 3 ,
The first pixel circuit includes a first capacitor element,
The second pixel circuit includes a second capacitor element,
A first electrode of the first capacitor is electrically connected to a gate of the first driving transistor;
A second electrode of the first capacitor is electrically connected to one of a source and a drain of the first driving transistor;
A first electrode of the second capacitor element is electrically connected to a gate of the second driving transistor;
The image display device, wherein the second electrode of the second capacitor element is electrically connected to one of a source and a drain of the second driving transistor. In any one of Claims 1 thru | or 4 ,
The image display device, wherein the inspection area is provided at an outer edge of the display area. An electronic apparatus using the image display device according to any one of claims 1 to 5 .

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