WO2008050380A1

WO2008050380A1 - Display panel testing apparatus and testing method

Info

Publication number: WO2008050380A1
Application number: PCT/JP2006/321037
Authority: WO
Inventors: Masato Togashi; Keisuke Moriya
Original assignee: Pioneer Corporation; Tohoku Pioneer Corporation
Priority date: 2006-10-23
Filing date: 2006-10-23
Publication date: 2008-05-02

Abstract

An apparatus for testing a display panel (1) in which display elements (E11-Emn) are connected in a matrix at respective ones of the intersections of a plurality of anode lines (A1-Am) and a plurality of cathode lines (K1-Kn). A voltage from a test power supply (E1) is applied to the cathode line connected to a display element to be tested, while a voltage (ground potential) from a determination anode power supply, which is lower in voltage value than the test power supply (E1), is applied to the anode line connected to the display element to be tested. In the meantime, the voltage of a non-determination power supply (E2), which has the same voltage value as the test power supply (E1), is applied to each of the cathode and anode lines that are not connected to the display element to be tested. In the structure described heretofore, the value of a current flowing from the test power supply (E1) is determined by a current determining means (2), whereby the potentially defective state of the display element to be tested can be examined with precision without receiving the affection of a 'sneak current' via an defective element that is not the display element to be tested.

Description

Specification

Display panel inspection apparatus and inspection method

Technical field

TECHNICAL FIELD [0001] The present invention relates to a display panel inspection apparatus and inspection method using a capacitive element such as an organic EL (elect mouth luminescence) element as a display pixel.

Background art

[0002] The development of a display using a light-emitting display panel formed by arranging light-emitting elements in a matrix has been widely promoted. As a light-emitting element used in such a display panel, an organic EL element using an organic material for a light-emitting layer has attracted attention, and a part of it has already been commercialized. This is also due to the fact that the use of organic compounds that can be expected to have good light-emitting characteristics for the light-emitting layer of EL devices has led to higher efficiency and longer life that can withstand practical use.

[0003] The organic EL element described above is basically a transparent electrode constituting an anode (anode) on a transparent substrate, a light emitting functional layer containing an organic compound, and a cathode (force sword), for example, a metal electrode. Are stacked. Therefore, this organic EL element can be electrically replaced with a light emitting element having a diode characteristic and a parasitic capacitance component coupled in parallel to the light emitting element, and the organic EL element is a capacitive light emitting element. Can do.

[0004] By the way, in the display panel in which the organic EL elements are arranged in a matrix, the organic layer functioning as a light emitting layer is laminated unevenly in the manufacturing process, or when a thin film such as a cathode electrode is laminated. In some cases, dot defects are generated by damaging the organic layer or by oxidizing the cathode electrode itself with impurities.

[0005] In many cases, the above-described dot defects are electrically short-circuited. In such cases, the EL element in the defective state is connected to the anode line or the cathode line connected thereto. There is also a problem of causing lighting failures to other EL elements. For this purpose, an inspection process is performed to detect EL elements with dot defects.

[0006] Since EL elements have diode characteristics as described above, each EL element is a matrix. Between the scanning lines (hereinafter also referred to as cathode lines) and the drive lines (hereinafter also referred to as anode lines) connected in the form of a voltage having a polarity opposite to the forward voltage applied during light emission driving, In other words, a defective EL element can be detected by applying a reverse bias voltage. As described above, Patent Document 1 discloses a detection means for applying a reverse bias voltage to each EL element connected in a matrix.

Patent Document 1: Japanese Patent Laid-Open No. 2003-229262

[0007] By the way, in the inspection apparatus disclosed in Patent Document 1, an ammeter is connected to each of the scanning lines and to each of the drive lines, and each ammeter is monitored to detect defective elements. It tries to detect the exact position. In this case, the position of the short-circuited element can be easily determined from the connection position of the ammeter on the drive line side where the predetermined current value is measured and the connection position of the ammeter on the scan line side where the predetermined current value is also measured. It is explained that can be known.

[0008] However, in a display panel in which the light emitting elements are arranged in a matrix, if there are two or more defective elements on the display panel, the display panel is combined with other normal elements. As a result, a sneak current described later is generated in the display panel, which makes it difficult to grasp the exact position of the defect element.

FIG. 1 illustrates the above-described problem. Reference numeral 1 denotes a display panel, and a configuration other than the display panel 1 constitutes a display panel inspection apparatus. Here, in display panel 1, m anode lines Al to Am are arranged in the vertical direction, and n cathode lines Kl to Κη are arranged in the horizontal direction, and at each intersecting portion (a total of m X n locations), Display elements (EL elements) E11 to Emn indicated by a parallel combination of diode and capacitor symbol marks constitute display panel 1.

[0010] Although not shown in the figure, the anode lines Al to Am in the display panel 1 are connected to an anode line drive circuit having a constant current source, and the cathode lines Kl to Kn have cathode line drive circuits. Connected. The cathode line scanning circuit sequentially sets the cathode lines to be scanned to the scanning potential, and in synchronization with this, the anode line drive circuit selectively supplies a forward current to the anode lines Al to Am, thereby displaying the display. The display elements arranged in panel 1 are controlled to be lit so that they can emit light continuously. In the inspection circuit shown in FIG. 1, one end of each of the cathode side switches Skl to Skn is connected to each of the cathode lines Kl to Κη, and the cathode side switches Skl to Skn are connected to the display panel 1 described above. The positive terminal of the power source E is connected to the other end via the current measuring means 2. One end of each of the anode side switches Sal to Sam is connected to each anode line Al to Am of the display panel 1, and the other end of each of the anode side switches Sal to Sam is connected to the negative terminal of the power source E. RU

That is, the power source E functions to apply a voltage having a reverse polarity to the forward voltage applied when the EL element in the display panel 1 is driven to emit light, that is, a reverse bias voltage.

In the configuration of the inspection circuit described above, in the case of inspecting the display element indicated by E33 indicated by a circle as an example, the cathode side switch Sk3 and the anode side switch Sa3 are turned on, and the other cathode side All switches and anode switches are set to the off state. As a result, a reverse bias voltage from the power source E is applied to the display element indicated by E33. At this time, if the display element E33 is normal, the current measuring means 2 does not detect the current value. Further, if the display element E33 is in a short circuit state, the current measuring means 2 detects a large current value and detects that this is a defect state.

On the other hand, as an example, when the display elements E23 and E31 in the display panel 1 shown in FIG. On the other hand, a sneak current indicated by a chain line from the cathode side switch Sk3 to the anode side switch Sa3 via the display elements E23, E21, E31 flows. In this case, even if the display element E33 is normal, an erroneous detection as if the display element E33 is in a short-circuit state occurs.

[0015] Further, as described above, the display element may cause a leakage phenomenon in which a current leaking in a reverse direction is slightly leaked in a completely short-circuited state. In this case, for example, when a leak occurs in the display elements E13 and E32, a wraparound leak current flows through the display element E12 as indicated by the dashed arrow, and similarly the display element E33 is normal. However, erroneous detection occurs as if the display element E33 is in a leak state.

[0016] Since the erroneous detection described above also occurs in the inspection apparatus disclosed in Patent Document 1 described above, each positive electrode corresponding to one cathode line is necessary for accurately grasping a defective element. The inspection for detecting the current value for each polar line is repeated, and the inspection for detecting the current value for each anode line is similarly repeated by changing the cathode line.

Disclosure of the invention

Problems to be solved by the invention

[0017] By the way, as described above, each of the display elements (EL elements) has a parasitic capacitance. Therefore, when the reverse bias voltage is charged for each of the elements as described above, It is necessary to detect the value of the current flowing through the display element after a sufficient time to charge the parasitic capacitance.

That is, when each element is inspected, it is necessary to detect the current value after a reverse bias voltage sufficient for the parasitic capacitance is charged, so that a display panel having a large number of elements is used. In this case, the cumulative total time that must be waited for after each device is provided with a reverse bias voltage increases, and a lot of inspection time is required.

[0019] The present invention has been made by paying attention to the above-mentioned problems, and it is possible to eliminate the standby time for charging the parasitic capacitance and to eliminate the occurrence of the sneak current as described above. It is an object of the present invention to provide an inspection apparatus and an inspection method capable of inspecting an element with high accuracy.

Means for solving the problem

[0020] A display panel inspection apparatus according to the present invention, which has been made to solve the above-mentioned problems, as described in claim 1, at each intersection position of a plurality of anode lines and a plurality of cathode lines intersecting each other. A display panel inspection apparatus comprising: a display element connected between the anode line and the cathode line, wherein a display operation is performed when the anode line force forward current is passed through the display element. And an inspection power source that is electrically connected to the cathode line of the display panel and outputs an inspection voltage, and is electrically connected to all anode lines and negative lines of the display panel, and all the anode lines and Electrode for setting the potential of the cathode line and the measurement target cathode line and the potential setting means connected to the display element to be measured

It is characterized in that it includes a current measuring means that is selectively connected to Z or a measurement target anode line and measures a current flowing in the display element to be measured.

[0021] Further, in order to solve the above-described problems, the display panel is inspected according to the present invention. The method according to claim 11, further comprising a display element connected between the anode line and the cathode line at each intersection position of the plurality of anode lines and the plurality of cathode lines intersecting each other. A display panel inspection method in which a display operation is performed by applying a forward current of the anode line force to an element, wherein an inspection voltage is applied to at least one of the cathode lines, and the potential of the cathode line is The electrode potential setting step for setting the potentials of all the anode lines and the cathode lines so as to have a relationship equal to or higher than the potentials of the anode lines, and the measurement target cathode lines and Z or measurement objects to which the display elements to be measured are connected The method is characterized in that a current measuring step is performed which is selectively connected to a positive electrode and measures the current flowing through the display element to be measured.

Brief Description of Drawings

FIG. 1 is a circuit configuration diagram showing an example of a conventional inspection apparatus together with a display panel.

FIG. 2 is a circuit configuration diagram showing a first embodiment of an inspection apparatus according to the present invention together with a display panel.

FIG. 3 is a circuit configuration diagram showing the second embodiment together with the display panel.

FIG. 4 is a circuit configuration diagram showing the third embodiment together with the display panel.

FIG. 5 is a circuit configuration diagram showing the fourth embodiment together with the display panel.

FIG. 6 is a circuit configuration diagram showing the fifth embodiment together with the display panel.

FIG. 7 is an explanatory view showing a defect state determination means performed in the inspection apparatus shown in FIG. 6.

Explanation of symbols

1 Table No

2 Current measurement means

3 Constant current source

4 Voltage measurement means

7 Cathode current measurement means

8 Anode current measuring means

9 Calculation means

E1 Inspection power supply E2 Non-measurement power supply

El l ~ Emn Display element

OP1 operational amplifier

SW main switch

BEST MODE FOR CARRYING OUT THE INVENTION

Hereinafter, an inspection apparatus for a display panel that is useful for the present invention will be described based on the embodiments shown in the drawings. FIG. 2 shows the first embodiment. Reference numeral 1 denotes the display panel already described with reference to FIG. 1, and therefore the description thereof is omitted. In the embodiment shown in FIG. 1, an inspection power source E1 for individually applying a reverse bias voltage to a display element (EL element) to be measured is provided, and a positive terminal of the inspection power source E1 One end of the current measuring means 2 is connected in series.

[0025] The other end of the current measuring means 2 is configured to be selectively connectable to the cathode lines Kl to Kn arranged on the display panel 1 through the switches Ski 1, Sk21, Sk31, ... Sknl. Thus, the positive voltage of the inspection power source E1 acts so as to be applied alternatively to the cathode lines Κ1 to Κη. In this embodiment, the negative terminal of the inspection power supply E1 is set to the ground potential.

[0026] Further, the switches Sai l, Sa21, Sa 31, ... Saml force are respectively connected to the anode lines Al to Am arranged on the display panel 1, and these switches Sai l, Sa21, Sa31, ... • •• The other end of Saml is connected to a measurement anode power source that can output a measurement anode voltage whose voltage value is lower than the positive voltage value of the inspection power source E1. In the embodiment shown in FIG. 2, the measurement anode voltage is set to the ground potential.

[0027] Then, the switches Sail, Sa21, Sa31,... Saml are selectively turned on, so that the measured anode voltage (grounding) with respect to any deviation of the anode lines Al to Am is detected. It works like an electric potential.

On the other hand, the cathode lines Kl to Kn arranged on the display panel 1 are further connected to switches Skl2, Sk22, Sk32,... Skn2, and via these switches, the positive voltage of the measurement power source E2 Is supplied to the cathode lines Kl to Kn. The negative terminal of the non-measuring power source 2 is set to the ground potential. [0029] The switches Ski 1, Sk21, Sk31, ... Sk nl connected to the cathode lines Kl to Kn and the switches Skl2, Sk22, Sk32, ... Skn2 are connected to each cathode line as shown in the figure. Accordingly, a pair is formed, and each switch constituting the pair is controlled so that one of them is turned on.

[0030] Further, switches Sal2, Sa22, Sa32,... Sam2 are further connected to the anode lines Al to Am arranged in the display panel 1, and the non-measurement power source E2 is connected to these switches via these switches. A positive voltage is configured to be supplied to the anode lines Al to Am.

[0031] The switches Sai l, Sa21, Sa31,... Sk ml connected to the anode lines Al to Am, and the switches Sal2, Sa22, Sa32,. A pair is formed corresponding to each of the switches, and each switch constituting the pair is controlled so that one of them is turned on.

In the embodiment shown in FIG. 2, the negative terminal of inspection power supply E1 and the negative terminal of non-measurement power supply E2 are both grounded, and the positive voltage value of inspection power supply E1 is The value of the positive voltage of the measuring power supply E2 is set to the relation, etc.!

[0033] In the configuration described above, the switch that forms a pair connected to the cathode lines Kl to Kn of the display panel 1 and the switch that forms a pair connected to the anode lines Al to Am each include a plurality of cathode lines. A plurality of selection means for selectively setting a plurality of types of potentials for 1 to Kn and a plurality of anode lines A 1 to Am are configured. The electrode potential setting means includes a plurality of selection means by each switch, the non-measurement power source E2, and the measurement anode power source (in this embodiment, the ground potential).

[0034] Further, the current measuring means 2 is selectively connected to the measurement target cathode line and the measurement target anode line, to which the display element to be measured is connected, via the selection means, and the measurement is performed. It fulfills the function of measuring the current flowing through the target display element.

The state shown in FIG. 2 shows an example in which a display element indicated by E33 indicated by a circle in the display panel 1 is inspected as an example! That is, when the switch Sk31 is turned on, the positive voltage of the inspection power supply E1, that is, the inspection voltage is applied to the cathode line K3 corresponding to the display element to be measured. In this case, display elements other than the measurement target are connected. Each of the switches Skl 1, Sk 21,... Sknl interposed between the non-measured cathode line and the inspection power supply El is put into a state of talent.

[0036] Further, when the switch Sa31 is turned on to the anode line A3 corresponding to the display element to be measured, the measurement anode voltage (in this embodiment, the ground potential) from the measurement anode power source is set. Supplied. In this case, each of the switches Sal 1, Sa21,... Saml interposed between the non-measurement anode line connected to the display element other than the measurement object and the measurement anode power source is turned off.

Thereby, a closed circuit including the inspection power source E1 and the current measuring means 2 is formed via the switch Sk31, the cathode line K3, the display element Ε33 to be measured, the anode line A3, and the switch Sa31, and the display element A reverse bias voltage is applied to E33 by the inspection power supply E1 (electrode potential setting step).

[0038] On the other hand, the switch Sk32 interposed between the cathode line K3 corresponding to the display element E33 to be measured and the positive terminal of the non-measurement power supply E2 is turned off, and the display elements other than the measurement object are connected. Each of the switches Ski 2, Sk22,... Skn2 interposed between the cathode line not measured and the positive terminal of the non-measuring power supply E2 is brought into a stale state.

[0039] In addition, the switch Sa32 interposed between the anode wire A3 corresponding to the display element E33 to be measured and the positive terminal of the non-measurement power supply E2 is turned off, and display elements other than the measurement object are connected. Each switch Sal2, Sa22,... Sam2 interposed between the measured non-measurement anode wire and the positive terminal of the non-measuring power supply E2 is brought into a stale state.

As a result, the reverse bias voltage from the inspection power supply E1 is applied only to the display element E33 to be measured, and the potentials at both ends of the display element that is not to be measured become the same potential. For this reason, even if a display element that is not to be measured is short-circuited, no current flows through the display element, as described with reference to FIG. Almost no "current" occurs!

As a result, it is possible to accurately measure the current value flowing through the display element E33 to be measured (current measurement step), and to identify whether the display element is in a short-circuited state or a leaked state. It can be detected with high accuracy.

[0042] Since the potentials at both ends of the display element that is not the measurement target are fixed to the same potential, Since the current consumed for charging the parasitic capacitance of the display element that is not the target is eliminated and only the charging of the parasitic capacitance of the element to be measured is required, the time to start measurement can be shortened.

[0043] Fig. 3 shows a second embodiment of an inspection apparatus according to the present invention. In FIG. 3, parts that perform the same functions as those shown in FIG. 2 are denoted by the same reference numerals, and therefore detailed description thereof is omitted.

In the embodiment shown in FIG. 3, the non-measurement power supply E2 shown in FIG. 2 is configured by an operational amplifier OP1. That is, the non-inverting input terminal of the operational amplifier OP1 is connected to the positive terminal of the inspection power supply E1, and the output terminal of the operational amplifier OP1 is connected to the inverting input terminal. That is, the operational amplifier OP1 functions as a buffer amplifier.

Accordingly, the output terminal of the operational amplifier OP1 performs the same function as the positive terminal of the non-measurement power supply E2 shown in FIG. 2, and the test voltage of the inspection power supply E 1 is connected to the output terminal of the operational amplifier OP 1. The same voltage value will be produced. Thereby, also in the second embodiment shown in FIG. 3, it is possible to obtain the same effects as those in the embodiment shown in FIG.

[0046] Fig. 4 shows a third embodiment of an inspection apparatus according to the present invention. In FIG. 4, parts that perform the same functions as those shown in FIG. 3 are denoted by the same reference numerals, and thus detailed description thereof is omitted.

[0047] In the embodiment shown in FIG. 4, the non-inverting input terminal of the operational amplifier OP1 is connected at the connection position between the current measuring means 2 and the switches Ski 1, Sk21, Sk31,. The rest is the same as the configuration shown in FIG.

[0048] According to this configuration, the non-measurement voltage in which the voltage drop by the current measuring means 2 is compensated for the output voltage from the inspection power supply E1 can be output to the output terminal of the operational amplifier OP1. Also in the third embodiment shown in FIG. 4, it is possible to obtain the same effects as those in the embodiment shown in FIG.

[0049] Fig. 5 shows a fourth embodiment of an inspection apparatus according to the present invention. In FIG. 5, parts that perform the same functions as those shown in FIG. 3 are denoted by the same reference numerals, and therefore detailed description thereof is omitted.

In the embodiment shown in FIG. 5, the inspection power source E 1 is replaced with the constant current source 3. ing. The output terminal of the constant current source 3 is connected to the non-inverting input terminal of the operational amplifier OP1, so that the voltage value at the output terminal of the operational amplifier OP1 always matches the voltage value at the output terminal of the constant current source 3. Controlled.

In this embodiment, voltage measuring means 4 is provided that can measure the voltage value across the constant current source 3 including the current measuring means 2 as necessary. Also in the fourth embodiment shown in FIG. 5, the same effects as those of the embodiment shown in FIG. 2 can be obtained.

FIG. 6 shows a fifth embodiment of the inspection apparatus according to the present invention, and reference numeral 1 denotes the display panel already described based on FIG. The explanation is omitted. In the embodiment shown in FIG. 6, the output of the inspection power source E 1 can be applied to the cathode lines Kl to Kn arranged on the display panel 1 via the main switch SW.

That is, a resistance element Rrl is connected in series to the main switch SW, and each switch Ski, Sk2, Sk3,... Having one end connected to the cathode lines Kl to Kn via the resistance element Rrl. ... Commonly connected to the other end of Skn. Each switch Ski, Sk2, Sk3, ... Skn connected to each cathode line Kl to Kn acts so as to be turned on alternatively during the execution of the inspection, so that the positive voltage of the inspection power source E 1 is reduced to the cathode line Kl to Acts as an alternative to Kn.

[0054] One end of each of the anode lines Al to Am arranged in the display panel 1 is connected to the switch Sal, Sa2, Sa3, ... 'Sam, and the other end is connected in common to the resistance element Rr2. It is connected to a measurement anode power source capable of outputting a measurement anode voltage having a voltage value lower than that of the inspection power source E1. In the embodiment shown in FIG. 6, the measurement anode voltage is set to the ground potential.

[0055] The switches Sal, Sa2, Sa3,... Sam connected to the anode lines Al to Am act so as to be selectively turned on when the inspection is performed. Acts so that pressure (ground potential) is applied alternatively to the anode wires Al to Am

[0056] In the embodiment shown in FIG. 6, the inspection power supply is provided on each of the cathode lines Kl to Kn. The resistance element Rrl connected in series with El is equipped with a voltmeter that can measure the voltage at both ends of the resistance element Rrl. This is a cathode current that substantially measures the amount of current flowing through the resistance element Rrl. The measuring means 7 is configured as follows.

[0057] In addition, a voltmeter capable of measuring the voltage at both ends of the resistance element Rr2 connected in series with the measurement anode power supply (ground potential) across the anode lines Al to Am. This constitutes a cathode current measuring means 8 that substantially measures the amount of current flowing through the resistance element Rr2.

On the other hand, resistance elements Rkl, Rk2, Rk3,... Rkn are connected between the inspection power source E1 and the cathode lines Kl to Kn, respectively, and the cathode lines Kl to The inspection voltage from the inspection power supply El is applied to Κη. Also, resistance elements Ral, Ra2, Ra3,... Ram are connected between the measurement anode power source (ground potential) and each of the anode lines Al to Am, and each anode is connected to each anode via these resistance elements. The voltage (ground potential) from the measurement anode power supply is applied to the wires Al to Am! Speak.

[0059] In the configuration described above, each switch Ski, Sk2, Sk3, ... Skn and each resistance element Rkl, Rk2, Rk3, ... Rkn, each connected to the cathode lines Kl to Kn of the display panel 1, the display panel Each of the switches Sal, Sa2, Sa3,... Sam and each of the resistance elements Ral, Ra2, Ra3,... Ram connected to one anode line Al to Am constitutes an electrode potential setting means.

The state shown in FIG. 6 shows an example in which a display element indicated by E33 indicated by a circle in the display panel 1 is inspected as an example! That is, the inspection voltage from the inspection power source E1 is applied to the cathode line K3 corresponding to the display element E33 to be measured by turning on the switch Sk3. In this case, the switches Ski, Sk2,... Sknl interposed between the non-measuring cathode line to which the display element other than the measuring object is connected and the inspection power source E1 are turned off.

[0061] Further, since the switch Sa3 is turned on to the anode line A3 corresponding to the display element E33 to be measured, the measurement anode voltage (ground potential) from the above-described measurement anode power source is supplied. . In this case, each of the switches Sal, Sa2,... Saml interposed between the non-measuring anode line to which the display element other than the measuring object is connected and the measuring anode power source is turned off. Made.

[0062] Thus, measurement is performed with the inspection power source E1 via the cathode current measuring means 7, the switch Sk3, the cathode line K3, the display element Ε33 to be measured, the anode line A3, the switch Sa3, and the anode current measuring means 8. A closed circuit is formed with the anode power source, and a reverse noise voltage is applied to the display element E33 based on the potential difference between the inspection power source E1 and the measurement anode power source.

At this time, the voltage from the inspection power supply El is applied to all the cathode lines in the display panel 1 through the resistance elements Rkl, Rk 2, Rk3,. A voltage from the measurement positive electrode power source is applied to the anode wire through the resistance elements Ral, Ra2, Ra3,.

[0064] As described above, the voltage value from the inspection power source E1 is set to a value V higher than the voltage value of the measurement anode power source, so that each display element in the display panel 1 has a forward direction. No current will flow. Therefore, almost no “sneak current” is generated through a defective element that is not measured, and the state of the display element E33 to be inspected is acquired by the cathode current measuring means 7 and the anode current measuring means 8. The current value can be verified with high accuracy.

[0065] According to the configuration shown in FIG. 6, when the main switch SW is turned on, the inspection power source E

As shown in Fig. 1, since the parasitic capacitance of all display elements is charged all at once, it is not necessary to charge the parasitic capacitance when measuring individual display elements. It can be greatly shortened.

[0066] In the embodiment shown in FIG. 6, based on the current measurement values obtained by the cathode current measuring means 7 and the anode current measuring means 8, the calculating means 9 has a force that causes the display panel 1 to be defective. It is configured to determine whether or not, and also determine the type of defect and the location of the defect.

FIG. 7 illustrates a defect state determination unit performed by the calculation unit 9 shown in FIG. In adopting the defect state determination means shown in FIG. 7, an inspection voltage (E1) is applied to each cathode line of a non-defective display panel, and the measured anode voltage is selectively applied to each anode line. A statistically defined maximum value and minimum value when is applied is used. That is, the maximum value of the current flowing through each cathode line in a normal display panel is shown as IKmax, the minimum value is shown as IKmin, the maximum value of current flowing through each anode line is shown as IAmax, and the minimum value is shown as IAmin. Therefore, it is judged as bad when the value is out of the range.

[0069] Then, the arithmetic means 9 shown in FIG. 6 has a No. 1 circuit according to the relationship between the current value flowing through the anode wire obtained by the anode current measuring means 8 and the current value flowing through the cathode wire obtained by the cathode current measuring means 7. As shown in 1 to 7, the determination is made according to the presence / absence of a defective display element, the location of the defective element, and the type of defect.

Note that, in the type of failure shown in FIG. 7, “separation failure” means a separation failure between adjacent electrodes, that is, a short state. “Dark line” means that the electrode is disconnected (electrically open).

In the embodiment shown in FIGS. 2 to 5, the current measuring means 2 is connected in series to the inspection power source E1, but this is connected to the inspection power source E1. It is also possible to adopt a configuration in which a resistance element is connected in series and the current value is obtained by measuring the voltage across the resistance element, that is, a configuration similar to the cathode current measuring means 7 shown in FIG.

[0072] In the above, the inspection apparatus and the inspection method have been described for a display panel using an organic EL element as a display element. However, the present invention is not limited to a display panel using an organic EL element. Other display panels having display elements having diode characteristics and capacitive properties can be targeted, and similar effects can be obtained.

Claims

The scope of the claims

[1] A display element connected between the anode line and the cathode line is provided at each intersection position of the plurality of anode lines and the plurality of cathode lines intersecting with each other, and the anode line force order with respect to the display element A display panel inspection device that performs display operation by flowing a directional current,

An inspection power source that is electrically connected to the cathode line of the display panel and outputs an inspection voltage;

Electrode potential setting means that is electrically connected to all anode lines and cathode lines of the display panel and sets potentials of all anode lines and cathode lines;

A current measuring means that is selectively connected to the measurement target cathode line and the Z or measurement target anode line to which the display element to be measured is connected, and measures the current flowing through the display element to be measured;

A display panel inspection apparatus, comprising:

[2] The electrode potential setting means includes a plurality of selection means for selectively setting a plurality of types of potentials to the plurality of cathode lines and the plurality of anode lines. The display panel inspection apparatus according to 1.

[3] In the electrode potential setting means,

The inspection power supply is connected to the measurement target cathode line,

A measuring anode power source that outputs a measuring anode voltage having a voltage value lower than the inspection voltage is connected to the measuring object anode wire,

A non-measurement voltage that outputs a non-measurement voltage to an unmeasured cathode line and a non-measuring display element connected to a non-measurement anode element. 3. The display panel inspection device according to claim 1, wherein a constant power source is connected.

[4] The display panel according to any one of claims 1 and 3, wherein the current measuring unit is selectively connected to the measurement target cathode line via the selection unit. Inspection equipment.

[5] The potential of the measurement anode voltage is a ground potential, 5. The display panel inspection apparatus according to claim 1, wherein voltage values of the non-measurement voltage and the inspection voltage are equal to each other.

[6] The electrode potential setting means includes:

Connect the inspection power supply to all the cathode lines,

2. The display panel inspection apparatus according to claim 1, wherein a measurement anode power source that outputs a measurement anode voltage whose voltage value is lower than the inspection voltage is connected to all the anode lines.

[7] The current measuring means includes

A cathode current measuring means which is selectively connected to the measurement target cathode line and measures a current flowing through the measurement target cathode line;

7. The display panel according to claim 1, further comprising an anode current measuring unit that is selectively connected to the measurement target anode line and that measures a current flowing through the measurement target anode line. 8. Inspection device.

8. The display panel inspection apparatus according to claim 1, wherein the potential of the measured anode voltage is a ground potential.

[9] Obtain an anode current value measured by the anode current measuring means and a cathode current value measured by the cathode current measuring means,

Calculation is performed using the obtained anode current value and cathode current value, and the presence / absence of a defective display element in the display panel, the location of the defective element, and the type of defect are determined based on the result of the calculation. 9. The display panel inspection apparatus according to claim 1, further comprising a calculation means.

[10] The current measurement means measures the voltage across the resistance element connected to the measurement target anode line or the measurement target cathode line, and converts the measured voltage value into a current value, thereby measuring the current. Claim 1 characterized by executing! 10. The display panel inspection device according to claim 9.

[11] A display element connected between the anode line and the cathode line is provided at each intersection position of the plurality of anode lines and the plurality of cathode lines intersecting each other, and the anode line is connected to the display element. A method for inspecting a display panel in which a display operation is performed by applying a forward current.

An electrode potential setting step in which an inspection voltage is applied to at least one of the cathode lines, and the potentials of all the anode lines and the cathode lines are set so that the potential of the cathode lines is equal to or higher than the potential of the anode lines; ,

A current measurement step of measuring a current flowing in the measurement target display element, which is selectively connected to the measurement target cathode line and Z or the measurement target anode line, to which the measurement target display element is connected, is executed A display panel inspection method characterized by the above.

[12] In the electrode potential setting step,

The inspection voltage is applied to the measurement target cathode line,

A voltage value lower than the inspection voltage is applied to the measurement target anode wire, a measurement anode voltage is applied,

A non-measuring voltage is applied to the non-measuring cathode line connected to the display element to be measured and the non-measuring anode line to which the display element to be measured is not connected. The method for inspecting a display panel according to claim 11.

13. The display panel inspection method according to claim 11, wherein in the current measurement step, a current flowing through the measurement target cathode line to which the inspection voltage is applied is measured.

[14] The potential of the measurement anode voltage is a ground potential,

14. The display panel inspection apparatus according to claim 11, wherein the non-measurement voltage and the inspection voltage are equal in voltage value.

[15] In the electrode potential setting step,

The inspection voltage is applied to all the cathode lines,

The voltage value is lower than the inspection voltage for all the anode wires! The measurement anode voltage is applied,

In the current measurement step,

A cathode current measurement step for measuring a current flowing through the measurement target cathode line, and an anode current measurement step for measuring a current flowing through the measurement target anode line are executed. 12. The display panel inspection method according to claim 11, characterized in that:

16. The display panel inspection method according to claim 11, wherein the potential of the measurement anode voltage is a ground potential.

[17] Obtain the anode current value measured in the anode current measurement step and the cathode current value measured in the cathode current measurement step;

An operation is performed using the obtained anode current value and the cathode current value,

16. The calculation step of determining the presence / absence of a defective display element in the display panel, the location of the defective element, and the type of defect based on the result of the calculation is further executed. The display panel inspection method according to claim 16.

[18] In the current measurement step, the current is measured by measuring the voltage across the resistance element connected to the measurement target cathode line or the measurement target anode line, and converting the measured voltage value into a current value. 18. The display panel inspection method according to claim 11, wherein the display panel inspection method is executed.