Light emitting diode display panel detection device and detection method

Abstract

The application discloses a light emitting diode display panel detection device and a detection method. The light emitting diode display panel detection device comprises m first connection lines, n second connection lines and a detection circuit. M and n are positive integers. The light emitting diode display panel comprises m*n light emitting diodes. Each first connection line is coupled to the positive electrode of n light emitting diodes. Each second connection line is coupled to the negative electrode of m light emitting diodes. In the light emitting diode display panel detection method, the detection circuit can selectively execute at least one of a first detection mode to a third detection mode on the m*n light emitting diodes to detect abnormal light emitting diodes.

Description

TECHNICAL FIELD

[0001] The present application relates to a display panel, and in particular to a light emitting diode display panel detection device and a light emitting diode display panel detection method. BACKGROUND

[0002] Generally speaking, most of the current light emitting diode display panel detection methods for detecting abnormal light emitting diodes usually use optical detection by ultraviolet light irradiation after mass transfer or image recognition detection after connecting to the system.

[0003] However, since the above-mentioned conventional detection methods only detect a single light emitting diode in each detection, if all the light emitting diodes are to be detected, it will take a very long time, resulting in poor detection efficiency of the light emitting diode display panel, which needs to be improved. SUMMARY

[0004] Therefore, the present application provides a light emitting diode display panel detection device and a light emitting diode display panel detection method to effectively solve the above-mentioned problems encountered by the prior art.

[0005] According to an embodiment of the present application, a light emitting diode display panel detection device is provided. In this embodiment, the light emitting diode display panel detection device is used to detect a light emitting diode display panel. The light emitting diode display panel includes m*n light emitting diodes, where m and n are positive integers.

[0006] The light emitting diode display panel detection device includes m first connection lines, n second connection lines, and a detection circuit. m and n are positive integers. Each first connection line is respectively coupled to the positive electrode of n light emitting diodes. Each second connection line is respectively coupled to the negative electrode of m light emitting diodes. The detection circuit is used to selectively execute at least one of a first detection mode, a second detection mode, and a third detection mode on the m*n light emitting diodes to detect abnormal light emitting diodes.

[0007] In the first detection mode, when any second connection line of the n second connection lines is activated, the detection circuit sequentially detects the m first connection lines; when any first connection line of the m first connection lines is activated, the detection circuit sequentially detects the n second connection lines. In the second detection mode, when the any second connection line is activated, the detection circuit simultaneously detects the m first connection lines. In the third detection mode, when the any first connection line is activated, the detection circuit simultaneously detects the n second connection lines.

[0008] In one embodiment, the detection circuit first performs the second detection mode or the third detection mode to detect the abnormality, and then determines whether the number of the abnormal light emitting diodes is greater than one or equal to one.

[0009] In one embodiment, if the number of the abnormal light emitting diodes is greater than one, the detection circuit performs the first detection mode to locate the abnormal light emitting diodes.

[0010] In one embodiment, if the number of the abnormal light emitting diodes is equal to one, the detection circuit performs the second detection mode or the third detection mode to locate the abnormal light emitting diodes.

[0011] In one embodiment, in the first detection mode, when the any second connection line is activated, the detection circuit sequentially detects whether the current between the m first connection lines and the any second connection line is abnormal; when the any first connection line is activated, the detection circuit sequentially detects whether the current between the n second connection lines and the any first connection line is abnormal.

[0012] In one embodiment, in the first detection mode, when the any second connection line is activated, the level of the any second connection line is opposite to that of the remaining n-1 second connection lines of the n second connection lines; when the any first connection line is activated, the level of the any first connection line is opposite to that of the remaining m-1 first connection lines of the m first connection lines.

[0013] In one embodiment, in the first detection mode, when the detection circuit detects the any first connection line, the level of the any first connection line is opposite to that of the remaining m-1 first connection lines of the m first connection lines; when the detection circuit detects the any second connection line, the level of the any second connection line is opposite to that of the remaining n-1 second connection lines of the n second connection lines.

[0014] In one embodiment, in the second detection mode, the detection circuit simultaneously detects whether the current between the m first connection lines and the any second connection line is abnormal.

[0015] In one embodiment, in the third detection mode, the detection circuit simultaneously detects whether the current between the n second connection lines and the any first connection line is abnormal.

[0016] In one embodiment, when the detection circuit performs the first detection mode, the abnormal conditions that the detection circuit can detect include open circuit, short circuit between the any first connection line and its adjacent first connection line, short circuit between the any second connection line and its adjacent second connection line, resistance of any light emitting diode or its connection path in the m*n light emitting diodes being too high, and resistance of the any second connection line being too high.

[0017] In one embodiment, when the detection circuit executes the second detection mode, the abnormal conditions that the detection circuit can detect include open circuit, short circuit between the any first connection line and the any second connection line, short circuit between the any second connection line and its adjacent second connection line, over-high resistance of the any light emitting diode or its connection path in the m*n light emitting diodes, and over-high resistance of the any second connection line.

[0018] In one embodiment, when the detection circuit executes the third detection mode, the abnormal conditions that the detection circuit can detect include open circuit, short circuit between the any first connection line and the any second connection line, short circuit between the any first connection line and its adjacent first connection line, over-high resistance of the any light emitting diode or its connection path in the m*n light emitting diodes, and over-high resistance of the any second connection line.

[0019] Another specific embodiment according to the present application is a light emitting diode display panel detection method. In this embodiment, the light emitting diode display panel detection method is used to detect a light emitting diode display panel. The light emitting diode display panel includes m*n light emitting diodes, where m and n are both positive integers.

[0020] The light emitting diode display panel detection method includes the following steps:

[0021] providing m first connection lines, n second connection lines, and a detection circuit, where each first connection line is coupled to the anodes of n light emitting diodes, and each second connection line is coupled to the cathodes of m light emitting diodes; and

[0022] The detection circuit selectively executes at least one of a first detection mode, a second detection mode, and a third detection mode on the m*n light emitting diodes to detect abnormal light emitting diodes.

[0023] In the first detection mode, when the any second connection line in the n second connection lines is activated, the detection circuit sequentially detects the m first connection lines; when the any first connection line in the m first connection lines is activated, the detection circuit sequentially detects the n second connection lines. In the second detection mode, when the any second connection line is activated, the detection circuit simultaneously detects the m first connection lines. In the third detection mode, when the any first connection line is activated, the detection circuit simultaneously detects the n second connection lines.

[0024] In one embodiment, the detection circuit first executes the second detection mode or the third detection mode for abnormality detection, and then determines whether the number of detected abnormal light emitting diodes is greater than 1 or equal to 1.

[0025] In one embodiment, if the number of abnormal LEDs detected is greater than 1, the detection circuit performs the first detection mode to locate the abnormal LED.

[0026] In one embodiment, if the number of abnormal LEDs detected is equal to 1, the detection circuit performs the second detection mode or the third detection mode to locate the abnormal LED.

[0027] In one embodiment, in the first detection mode, when the any second connection line is activated, the detection circuit sequentially detects whether the current between the m first connection lines and the any second connection line is abnormal; when the any first connection line is activated, the detection circuit sequentially detects whether the current between the n second connection lines and the any first connection line is abnormal.

[0028] In one embodiment, in the first detection mode, when the any second connection line is activated, the level of the any second connection line is opposite to that of the remaining n-1 second connection lines of the n second connection lines; when the any first connection line is activated, the level of the any first connection line is opposite to that of the remaining m-1 first connection lines of the m first connection lines.

[0029] In one embodiment, in the first detection mode, when the detection circuit detects the any first connection line, the level of the any first connection line is opposite to that of the remaining m-1 first connection lines of the m first connection lines; when the detection circuit detects the any second connection line, the level of the any second connection line is opposite to that of the remaining n-1 second connection lines of the n second connection lines.

[0030] In one embodiment, in the second detection mode, the detection circuit simultaneously detects whether the current between the m first connection lines and the any second connection line is abnormal.

[0031] In one embodiment, in the third detection mode, the detection circuit simultaneously detects whether the current between the n second connection lines and the any first connection line is abnormal.

[0032] In one embodiment, when the detection circuit performs the first detection mode, the abnormal conditions that the detection circuit can detect include open circuit, short circuit between the any first connection line and its adjacent first connection line, short circuit between the any second connection line and its adjacent second connection line, over-high resistance of any LED or its connection path of the m*n LEDs, and over-high resistance of the any second connection line.

[0033] In an embodiment, when the detection circuit executes the second detection mode, the abnormal conditions that the detection circuit can detect include open circuit, short circuit between the any first connection line and the any second connection line, short circuit between the any second connection line and its adjacent second connection line, too high resistance of the any light emitting diode or its connection path in the m*n light emitting diodes, and too high resistance of the any second connection line.

[0034] In an embodiment, when the detection circuit executes the third detection mode, the abnormal conditions that the detection circuit can detect include open circuit, short circuit between the any first connection line and the any second connection line, short circuit between the any first connection line and its adjacent first connection line, too high resistance of the any light emitting diode or its connection path in the m*n light emitting diodes, and too high resistance of the any second connection line.

[0035] Compared with the prior art, the light emitting diode display panel detection device and the light emitting diode display panel detection method according to the present application utilize the output channels of the light emitting diode display driving circuit to selectively pass through three different detection modes to detect the abnormality of all the light emitting diodes of the light emitting diode display panel, which not only can effectively detect various common abnormal conditions (such as open circuit, short circuit, or too high resistance, etc.) of the light emitting diode display panel, but also can greatly shorten the detection time required for detecting all the light emitting diodes of the light emitting diode display panel, thereby effectively improving the detection efficiency of the light emitting diode display panel. In addition, the present application can further determine whether the light emitting diode with abnormality needs to be repaired subsequently according to the above detection result.

[0036] The advantages and spirits of the present application can be further understood through the following detailed description of the application and the accompanying drawings. BRIEF DESCRIPTION OF DRAWINGS

[0037] Figure 1 Voltage difference versus current change curve of a light emitting diode.

[0038] Figure 2 Schematic diagram of the light emitting diode display panel detection device of the present application operating in the first detection mode.

[0039] Figure 3 Schematic diagram of the light emitting diode display panel detection device of the present application operating in the second detection mode.

[0040] Figure 4 Schematic diagram of the light emitting diode display panel detection device of the present application operating in the third detection mode.

[0041] Figure 5A schematic diagram for the LED display panel detection device of the present application applied to open circuit (Open) detection of the LED.

[0042] Figure 6 A schematic diagram for the LED display panel detection device of the present application applied to short circuit (Short) detection between the first connection line and the second connection line.

[0043] Figure 7 A schematic diagram for the LED display panel detection device of the present application applied to short circuit (Short) detection between two first connection lines.

[0044] Figure 8 A schematic diagram for the LED display panel detection device of the present application applied to short circuit (Short) detection between two second connection lines.

[0045] Figure 9 A schematic diagram for the LED display panel detection device of the present application detecting whether the resistance value of the LED or the coupling path thereof is too high.

[0046] Figure 10 A schematic diagram for the LED display panel detection device of the present application detecting whether the resistance value of the second connection line is too high.

[0047] Figure 11 A schematic diagram for the range interval of the current detection result.

[0048] Figure 12 A flow chart of the LED display panel detection method according to another preferred embodiment of the present application.

[0049] Main element symbol explanation:

[0050] S11-S18: steps

[0051] VTH: threshold voltage

[0052] ITH: threshold current

[0053] I: current

[0054] IH: current

[0055] IL: current

[0056] V: voltage

[0057] VH: voltage

[0058] VL: voltage

[0059] TC: detection circuit

[0060] A1-Am: first connection line

[0061] C1-Cn: second connection line

[0062] LED11-LEDmn: light emitting diode

[0063] OP: open circuit

[0064] SH: short circuit

[0065] R: resistance value

[0066] PASS: passing detection area

[0067] IS: short circuit judgment current value

[0068] IR: high resistance judgment current value

[0069] IO: open circuit judgment current value

[0070] HR: high resistance area

[0071] ID: current

[0072] VCA: voltage DETAILED DESCRIPTION

[0073] According to an embodiment of the present application, a light emitting diode display panel detection device is provided. In this embodiment, the light emitting diode display panel detection device is used to detect a light emitting diode display panel. The light emitting diode display panel is driven by a passive driving method, but is not limited thereto.

[0074] Please refer to Figure 1 , Figure 1 for a voltage versus current curve of a light emitting diode. As shown in Figure 1 , when the voltage has not reached its threshold voltage VTH, the current IL of the light emitting diode corresponding to the voltage VL is relatively small. When the voltage exceeds its threshold voltage VTH, the current IH of the light emitting diode corresponding to the bias voltage VH is the normal current size.

[0075] Next, please refer to Figures 2 to 4 . Figure 2 for a schematic diagram of the light emitting diode display panel detection device of the present application operating in a first detection mode; Figure 3 for a schematic diagram of the light emitting diode display panel detection device of the present application operating in a second detection mode; Figure 4 for a schematic diagram of the light emitting diode display panel detection device of the present application operating in a third detection mode.

[0076] As shown in Figures 2 to 4As shown, the LED display panel may contain m*n LEDs LED11 to LEDmn, where m and n are both positive integers. The LED display panel detection device includes m first connecting lines A1 to Am, n second connecting lines C1 to Cn, and a detection circuit TC.

[0077] It should be noted that each first connecting line is coupled to the positive terminals of n LEDs respectively. That is, the first connecting line A1 is coupled to the positive terminals of n LEDs LED11 to LED1n respectively; the first connecting line A2 is coupled to the positive terminals of n LEDs LED21 to LED2n respectively; the first connecting line A3 is coupled to the positive terminals of n LEDs LED31 to LED3n respectively; and so on, until the first connecting line Am is coupled to the positive terminals of n LEDs LEDm1 to LEDmn respectively.

[0078] Furthermore, each second connecting line is coupled to the negative terminals of m LEDs. That is, the second connecting line C1 is coupled to the negative terminals of m LEDs LED11 to LEDm1; the second connecting line C2 is coupled to the negative terminals of m LEDs LED12 to LEDm2; the second connecting line C3 is coupled to the negative terminals of m LEDs LED13 to LEDm3; and so on, until the second connecting line Cn is coupled to the negative terminals of m LEDs LED1n to LEDmn.

[0079] It should be noted that the LED display panel of the present invention adopts a passive driving method, which causes the LEDs to emit light by changing the voltage difference between the first connecting lines A1-Am and the second connecting lines C1-Cn. The detection circuit TC can selectively execute at least one of the first detection mode, the second detection mode, and the third detection mode for the m*n LEDs LED11-LEDmn to detect abnormal LEDs.

[0080] like Figure 2 As shown, in the first detection mode, when any of the n second connecting lines C1 to Cn, Cj, is activated, the detection circuit TC will "sequentially" detect the m first connecting lines A1 to Am, where j = 1 to n; when any of the m first connecting lines A1 to Am, Ai, is activated, the detection circuit TC will "sequentially" detect the n second connecting lines C1 to Cn, where i = 1 to m.

[0081] For example, when the second connection line C1 is activated (at this time, the level of the second connection line C1 is opposite to the levels of the remaining second connection lines C2~Cn), the detection circuit TC will "sequentially" detect the first connection line Al (at this time, the level of the first connection line Al is opposite to the levels of the remaining first connection lines A2~Am), the first connection line A2 (at this time, the level of the first connection line A2 is opposite to the levels of the remaining first connection lines Al, A3~Am), the first connection line A3 (at this time, the level of the first connection line A3 is opposite to the levels of the remaining first connection lines Al~A2, A4~Am),..., until the first connection line Am (at this time, the level of the first connection line Am is opposite to the levels of the remaining first connection lines Al~A(m-1)).

[0082] Next, switching to the second connection line C2 is activated. When the second connection line C2 is activated (at this time, the level of the second connection line C2 is opposite to the levels of the remaining second connection lines Cl, C3~Cn), the detection circuit TC will "sequentially" detect the first connection line Al (at this time, the level of the first connection line Al is opposite to the levels of the remaining first connection lines A2~Am), the first connection line A2 (at this time, the level of the first connection line A2 is opposite to the levels of the remaining first connection lines Al, A3~Am), the first connection line A3 (at this time, the level of the first connection line A3 is opposite to the levels of the remaining first connection lines Al~A2, A4~Am),..., until the first connection line Am (at this time, the level of the first connection line Am is opposite to the levels of the remaining first connection lines Al~A(m-1)).

[0083] As for the subsequent sequential switching to the second connection lines C3~Cn activated, it can be similarly deduced, and thus will not be described here.

[0084] When the second connection lines Cl~Cn are sequentially activated, switching to the first connection lines Al~Am will begin.

[0085] When the first connection line Al is activated (at this time, the level of the first connection line Al is opposite to the levels of the remaining first connection lines A2~Am), the detection circuit TC will "sequentially" detect the second connection line Cl (at this time, the level of the second connection line Cl is opposite to the levels of the remaining second connection lines C2~Cn), the second connection line C2 (at this time, the level of the second connection line C2 is opposite to the levels of the remaining second connection lines Cl, C3~Cn), the second connection line C3 (at this time, the level of the second connection line C3 is opposite to the levels of the remaining second connection lines Cl~C2, C4~Cn),..., until the second connection line Cn (at this time, the level of the second connection line Cn is opposite to the levels of the remaining second connection lines Cl~C(n-1)).

[0086] Next, switching to the first connection line A2 actuation. When the first connection line A2 actuation (at this time the level of the first connection line A2 and the rest of the first connection line A1, A3 ~ Am level opposite), the detection circuit TC will be "in turn" detection of the second connection line C1 (at this time the level of the second connection line C1 and the rest of the second connection line C2 ~ Cn level opposite), the second connection line C2 (at this time the level of the second connection line C2 and the rest of the second connection line C1, C3 ~ Cn level opposite), the second connection line C3 (at this time the level of the second connection line C3 and the rest of the second connection line C1 ~ C2, C4 ~ Cn level opposite),..., until the second connection line Cn (at this time the level of the second connection line Cn and the rest of the second connection line C1 ~ C(n-1) level opposite).

[0087] As the subsequent switching to the first connection line A3 ~ Am actuation case can be similarly, so here will not be described.

[0088] In practical applications, in the first detection mode, when the second connection line C1 actuation, detection circuit TC "in turn" detection of the first connection line A1, A2, A3,..., Am and the second connection line C1 between the current is abnormal, and at this time the second connection line C1 and the rest of the second connection line C2, C3,..., Cn level opposite; when the first connection line A1 actuation, detection circuit TC "in turn" detection of the second connection line C1, C2, C3,..., Cn and the first connection line A1 between the current is abnormal, and at this time the first connection line A1 and the rest of the first connection line A2, A3,..., Am level opposite. The rest can be similarly, so here will not be described.

[0089] Similarly, in the first detection mode, when the second connection line C2 actuation, detection circuit TC "in turn" detection of the first connection line A1, A2, A3,..., Am and the second connection line C2 between the current is abnormal, and at this time the second connection line C2 and the rest of the second connection line C1, C3,..., Cn level opposite; when the first connection line A2 actuation, detection circuit TC "in turn" detection of the second connection line C1, C2, C3,..., Cn and the first connection line A2 between the current is abnormal, and at this time the first connection line A2 and the rest of the first connection line A1, A3,..., Am level opposite. The rest can be similarly, so here will not be described.

[0090] In the first detection mode, when the detection circuit TC detects the first connection line A1, the first connection line A1 and the rest of the first connection line A2, A3,..., Am level opposite; when the detection circuit TC detects the second connection line C1, the second connection line C1 and the rest of the second connection line C2, C3,..., Cn level opposite. The rest can be similarly, so here will not be described.

[0091] Similarly, in the first detection mode, when the detection circuit TC detects the first connection line A2, the level of the first connection line A2 is opposite to that of the other first connection lines A1, A3, ..., Am; when the detection circuit TC detects the second connection line C2, the level of the second connection line C2 is opposite to that of the other second connection lines C1, C3, ..., Cn. The rest can be deduced similarly, so they will not be elaborated further here.

[0092] In practical applications, when the detection circuit TC executes the first detection mode, the detection circuit TC can detect a variety of common abnormal conditions of the LED display panel, such as LED open circuit, short circuit between the first connecting line and its adjacent first connecting line, short circuit between the second connecting line and its adjacent second connecting line, excessive resistance of the LED or connecting path, and excessive resistance of the second connecting line, but not limited to these abnormal conditions.

[0093] like Figure 3 As shown, in the second detection mode, when any of the n second connecting lines C1 to Cn, Cj, is activated, the detection circuit TC will "simultaneously" detect the m first connecting lines A1 to Am, where j = 1 to n.

[0094] For example, when the second connecting line C1 is activated (at this time, the level of the second connecting line C1 is opposite to the levels of the other second connecting lines C2 to Cn), the detection circuit TC will "simultaneously" detect the first connecting lines A1, A2, A3, ..., Am. Similarly, when the second connecting line C2 is activated (at this time, the level of the second connecting line C2 is opposite to the levels of the other second connecting lines C1, C3 to Cn), the detection circuit TC will "simultaneously" detect the first connecting lines A1, A2, A3, ..., Am. The rest can be deduced similarly, so they will not be elaborated further here.

[0095] In practical applications, under the second detection mode, when the second connecting line C1 is activated (at this time, the level of the second connecting line C1 is opposite to the levels of the other second connecting lines C2 to Cn), the detection circuit TC "simultaneously" detects whether the current between the first connecting lines A1, A2, A3, ..., Am and the second connecting line C1 is abnormal. Similarly, when the second connecting line C2 is activated (at this time, the level of the second connecting line C2 is opposite to the levels of the other second connecting lines C1, C3 to Cn), the detection circuit TC "simultaneously" detects whether the current between the first connecting lines A1, A2, A3, ..., Am and the second connecting line C2 is abnormal. The rest can be deduced similarly, so they will not be elaborated further here.

[0096] When the detection circuit TC executes the second detection mode, the detection circuit TC can detect a plurality of common abnormal conditions of the light emitting diode display panel, such as open circuit of the light emitting diode, short circuit between the first connection line and the second connection line, short circuit between the second connection line and its adjacent second connection line, too high resistance of the light emitting diode or the connection path, and too high resistance of the second connection line, but not limited thereto.

[0097] As shown in FIG. 3, when any one of the m first connection lines Ai (i = 1 ~ m) is activated in the third detection mode, the detection circuit TC can "simultaneously" detect the n second connection lines Ci (i = 1 ~ n). Figure 4 For example, when the first connection line A1 is activated (at this time, the level of the first connection line A1 is opposite to that of the remaining first connection lines A2 ~ Am), the detection circuit TC can "simultaneously" detect the second connection lines C1, C2, C3, …, Cn. Similarly, when the first connection line A2 is activated (at this time, the level of the first connection line A2 is opposite to that of the remaining first connection lines A1, A3 ~ Am), the detection circuit TC can "simultaneously" detect the second connection lines C1, C2, C3, …, Cn. The rest can be deduced in the same way, and thus will not be described here.

[0098] In practical applications, when the first connection line A1 is activated (at this time, the level of the first connection line A1 is opposite to that of the remaining first connection lines A2 ~ Am) in the third detection mode, the detection circuit simultaneously detects whether the current between the second connection lines C1, C2, C3, …, Cn and the first connection line A1 is abnormal. Similarly, when the first connection line A2 is activated (at this time, the level of the first connection line A2 is opposite to that of the remaining first connection lines A1, A3 ~ Am), the detection circuit simultaneously detects whether the current between the second connection lines C1, C2, C3, …, Cn and the first connection line A2 is abnormal. The rest can be deduced in the same way, and thus will not be described here.

[0099] When the detection circuit TC executes the third detection mode, the detection circuit TC can detect a plurality of common abnormal conditions of the light emitting diode display panel, such as open circuit of the light emitting diode, short circuit between the first connection line and the second connection line, short circuit between the first connection line and its adjacent first connection line, too high resistance of the light emitting diode or the connection path, and too high resistance of the second connection line, but not limited thereto.

[0100] It should be noted that the detection circuit TC of the present application can first execute the second detection mode or the third detection mode for abnormality detection, and then determine whether the number of abnormal light emitting diodes detected is greater than 1 or equal to 1.

[0101]

[0102] ​If the number of abnormal LEDs detected by the detection circuit TC is greater than 1, it means that there are multiple abnormal LEDs in the LED display panel, and thus the detection circuit TC needs to further perform the first detection mode to locate the abnormal LEDs. If the number of abnormal LEDs detected by the detection circuit TC is equal to 1, it means that there is only one abnormal LED in the LED display panel, and thus the detection circuit TC only needs to perform the second detection mode or the third detection mode to locate the abnormal LED.

[0103] Thus, the detection circuit TC of the present application can quickly and accurately locate one or more abnormal LEDs in the LED display panel, and can further determine whether the abnormal LEDs need to be repaired according to the detection result.

[0104] Please refer to Figures 5 to 10 , Figures 5 to 10 respectively as the schematic diagrams of the LED display panel detection device of the present application applied to LED open circuit (Open) detection, LED short circuit (Short) detection, short circuit detection between two adjacent first connection lines, short circuit detection between two adjacent second connection lines, detection of whether the resistance value of the LED or its coupling path is too high, and detection of whether the resistance value of the second connection line is too high.

[0105] As shown in Figure 5 , the detection circuit TC can perform the first detection mode, the second detection mode, or the third detection mode to detect the open circuit OP phenomenon of the LED LED11.

[0106] For example, in the first detection mode, when the second connection line C1 is activated, the detection circuit TC can provide a voltage VH on the first connection line A1 and zero voltage on the remaining first connection lines A2-Am, and provide zero voltage on the second connection line C1 and voltage VH on the remaining second connection lines C2-Cn, to detect whether the current of the first connection line A1 is much smaller than the current IH corresponding to the voltage VH. If the measured current is much smaller than the current IH, it means that there is an open circuit OP phenomenon here. The rest can be deduced in the same way, which will not be described here.

[0107] As shown in Figure 6 , the detection circuit TC can perform the first detection mode, the second detection mode, or the third detection mode to detect the short circuit SH phenomenon between the first connection line A1 and the second connection line C1.

[0108] For example, in the second detection mode, when the second connection line C1 is activated, the detection circuit TC can provide voltage VL to all first connection lines A1 to Am, and provide zero voltage to the second connection line C1 and voltage VH to the remaining second connection lines C2 to Cn, to detect whether the current in the first connection lines A1 to Am is much greater than the current IL corresponding to voltage VL. If the measured current is much greater than current IL, it indicates that there is a short circuit SH at this point. The rest can be deduced similarly, and will not be elaborated further here.

[0109] like Figure 7 As shown, the detection circuit TC can execute the first detection mode, the second detection mode, or the third detection mode to detect the phenomenon of a short circuit SH between two adjacent first connection lines A1 and A2.

[0110] For example, in the first detection mode, when the second connection line C1 is activated, the detection circuit TC provides a voltage VL to the first connection line A1 and zero voltage to the remaining first connection lines A2 to Am, and provides zero voltage to the second connection line C1 and voltage VH to the remaining second connection lines C2 to Cn, to detect whether the current in the first connection line A1 is much greater than the current IL corresponding to the voltage VL. Then, when switching to the first connection line A2, the detection circuit TC provides a voltage VL to the first connection line A2 and zero voltage to the remaining first connection lines A1, A3 to Am, and provides zero voltage to the second connection line C1 and voltage VH to the remaining second connection lines C2 to Cn, to detect whether the current in the first connection line A2 is much greater than the current IL corresponding to the voltage VL. In this embodiment, the measured currents in both the first connection line A1 and the first connection line A2 are much greater than the current IL, indicating a short circuit SH between adjacent first connection lines A1 and A2. The rest can be deduced similarly and will not be elaborated further here.

[0111] like Figure 8 As shown, the detection circuit TC can execute the first detection mode, the second detection mode, or the third detection mode to detect the phenomenon of a short circuit SH between two adjacent second connection lines C1 and C2.

[0112] For example, in the second detection mode, the detection circuit TC can provide the voltage VL to the first connection lines A1-Am, and provide the zero voltage to the second connection line C1 and the voltage VH to the remaining second connection lines C2-Cn, to detect whether the current of the first connection lines A1-Am is much smaller than the current IH corresponding to the voltage VH. Then, when switching to the second connection line C2, the detection circuit TC can provide the voltage VL to the first connection lines A1-Am, and provide the zero voltage to the second connection line C2 and the voltage VH to the remaining second connection lines C1, C3-Cn, to detect whether the current of the first connection lines A1-Am is much smaller than the current IH corresponding to the voltage VH. In this embodiment, the currents measured in the above two switching conditions are both much smaller than the current IH corresponding to the voltage VH, which means that the short circuit SH occurs between the adjacent second connection lines C1 and C2. The remaining can be similarly deduced, and will not be described herein.

[0113] As shown in FIG. 1, the detection circuit TC can perform the first detection mode, the second detection mode, or the third detection mode to detect whether the resistance value R of the light emitting diode (e.g., LED 11) or the coupling path thereof is too high. Figure 9

[0114] For example, in the second detection mode, the detection circuit TC can provide the voltage VH to the first connection lines A1-Am, and provide the zero voltage to the second connection line C1 and the voltage VH to the remaining second connection lines C2-Cn, to detect whether the current of the first connection line A1 is smaller than the current IH corresponding to the voltage VH, and the currents of the remaining first connection lines A2-Am are smaller than the current IL corresponding to the voltage VL. If the current of the first connection line A1 is smaller than the current IH corresponding to the voltage VH and the currents of the remaining first connection lines A2-Am are smaller than the current IL corresponding to the voltage VL, it means that the resistance value R of the light emitting diode LED 11 (or the coupling path thereof) is too high, which can cause the phenomenon of insufficient light emitting brightness. The remaining can be similarly deduced, and will not be described herein.

[0115] As shown in FIG. 1, the detection circuit TC can perform the first detection mode, the second detection mode, or the third detection mode to detect whether the resistance value R of the light emitting diode (e.g., LED 11) or the coupling path thereof is too high. Figure 10

[0116] ​​For example, in the first detection mode, when the second connection line C1 is activated, the detection circuit TC can provide a voltage VH on the first connection line A1 and zero voltages on the remaining first connection lines A2-Am, and provide a zero voltage on the second connection line C1 and voltages VH on the remaining second connection lines C2-Cn, to detect whether the current of the first connection line A1 is less than the current IH corresponding to the voltage VH. Then, when switching to the first connection line A2, the detection circuit TC can provide a voltage VH on the first connection line A2 and zero voltages on the remaining first connection lines A1, A3-Am, to detect whether the current of the first connection line A2 is less than the current IH corresponding to the voltage VH. In this way, since the resistance value R of the second connection line C1 is too high, the currents of the first connection lines A1-Am detected by the detection circuit TC are all less than the current IH. As for the remaining second connection lines C2-Cn, since the resistance values R of the second connection lines C2-Cn are not too high, the currents of the first connection lines A1-Am are not less than the current IH.

[0117] Please refer to Figure 11 , Figure 11 for the schematic diagram of the range interval of the current detection result. As shown in Figure 11 , when the above-mentioned various abnormal phenomena occur, there are different corresponding relationships between the voltage and the current. Among them, IO is the open circuit judgment current value; IS is the short circuit judgment current value; IR is the high resistance judgment current value.

[0118] Under different voltages VCA, when the current ID≦the open circuit judgment current value IO, it represents that the open circuit OP phenomenon occurs; when the current ID≧the short circuit judgment current value IS, it represents that the short circuit SH phenomenon occurs. In addition, since the resistance value R is too high, it will cause the voltage drop of the light emitting diode, so under the same bias condition, a smaller high resistance judgment current value IR (such as the high resistance value region HR in Figure 11 ) is obtained. As for the detection region PASS, it represents that no abnormal situation occurs, so it can be detected.

[0119] Another specific embodiment according to the present application is a light emitting diode display panel detection method.

[0120] In this embodiment, the light emitting diode display panel detection method is used to detect a light emitting diode display panel. The light emitting diode display panel includes m*n light emitting diodes, where m and n are both positive integers. The light emitting diode display panel detection method includes the following steps:

[0121] providing m first connection lines, n second connection lines and a detection circuit, where each first connection line is respectively coupled to the positive electrode of n light emitting diodes, and each second connection line is respectively coupled to the negative electrode of m light emitting diodes; and

[0122] The detection circuit TC selectively performs at least one of a first detection mode, a second detection mode and a third detection mode on the m*n light emitting diodes to detect abnormal light emitting diodes.

[0123] In the first detection mode, when any one of the n second connection lines is activated, the detection circuit sequentially detects the m first connection lines; when any one of the m first connection lines is activated, the detection circuit sequentially detects the n second connection lines. In the second detection mode, when a second connection line is activated, the detection circuit simultaneously detects the m first connection lines. In the third detection mode, when any one of the m first connection lines is activated, the detection circuit simultaneously detects the n second connection lines.

[0124] Please refer to Figure 12 , Figure 12 the flowchart of the light emitting diode display panel detection method in this embodiment.

[0125] As shown in Figure 12 , the light emitting diode display panel detection method can include the following steps:

[0126] Step S11: the detection circuit switches to the second detection mode or the third detection mode;

[0127] Step S12: abnormality detection is performed;

[0128] If the abnormality detection result of step S12 is yes, step S13 is performed: whether the number of detected abnormal light emitting diodes is greater than 1 is determined; if the abnormality detection result of step S12 is no, step S16 is performed: the abnormality detection is completed;

[0129] If the determination result of step S13 is yes, i.e. the number of abnormal light emitting diodes is greater than 1, steps S14-S16 are sequentially performed: after the detection circuit switches to the first detection mode and locates the abnormal light emitting diode, the abnormality detection is completed; if the determination result of step S13 is no, i.e. the number of abnormal light emitting diodes is equal to 1, steps S15 and S16 are directly performed: after the abnormal light emitting diode is located, the abnormality detection is completed;

[0130] Step S17: after the abnormality detection is completed, whether the abnormal light emitting diode needs to be repaired is determined;

[0131] If the determination result of step S17 is yes, step S18 is performed: the abnormal light emitting diode is repaired; and if the determination result of step S17 is no, the detection process of the entire light emitting diode display panel is ended.

[0132] Compared with the prior art, the light emitting diode display panel detection device and the light emitting diode display panel detection method according to the present application utilize the output channel of the light emitting diode display driving circuit to selectively pass through three different detection modes to detect the abnormality of all light emitting diodes of the light emitting diode display panel, which can not only effectively detect various common abnormal conditions (such as open circuit, short circuit, or excessive resistance value, etc.) of the light emitting diode display panel, but also greatly shorten the detection time required for detecting all light emitting diodes of the light emitting diode display panel, thereby effectively improving the detection efficiency of the light emitting diode display panel. In addition, the present application can further determine whether subsequent repair action is required for the light emitting diode with abnormality according to the above detection result.

[0133] The above detailed description of the preferred embodiments of the present application is intended to be illustrative and not limiting. Other variations and modifications of the application will occur to those skilled in the art upon reading the description of the application. Therefore, it will be understood that the application is not limited to the particular examples described above, but is intended to include all modifications and equivalents falling within the scope of the application.

Claims

1. A method for detecting a light-emitting diode (LED) display panel, characterized in that, The light emitting diode display panel includes m*n light emitting diodes, where m and n are positive integers. The light emitting diode display panel detection method includes the following steps: providing m first connection lines, n second connection lines, and a detection circuit, where each first connection line is coupled to the positive electrode of n light emitting diodes, and each second connection line is coupled to the negative electrode of m light emitting diodes; and The detection circuit selectively executes at least one of a first detection mode, a second detection mode, and a third detection mode on the m*n light emitting diodes. In the first detection mode, when the level of any second connection line of the n second connection lines is opposite to the levels of the remaining n-1 second connection lines of the n second connection lines, the detection circuit sequentially detects the m first connection lines, and when the level of any first connection line of the m first connection lines is opposite to the levels of the remaining m-1 first connection lines of the m first connection lines, the detection circuit sequentially detects the n second connection lines. In the second detection mode, when the level of any second connection line is opposite to the levels of the remaining n-1 second connection lines of the n second connection lines, the detection circuit simultaneously detects the m first connection lines. In the third detection mode, when the level of any first connection line is opposite to the levels of the remaining m-1 first connection lines of the m first connection lines, the detection circuit simultaneously detects the n second connection lines.

2. A method for detecting a light-emitting diode (LED) display panel, characterized in that, The light emitting diode display panel includes m*n light emitting diodes, where m and n are positive integers. The light emitting diode display panel detection method includes the following steps: providing m first connection lines, n second connection lines, and a detection circuit, where each first connection line is coupled to the positive electrode of n light emitting diodes, and each second connection line is coupled to the negative electrode of m light emitting diodes; and The detection circuit selectively executes at least one of a first detection mode, a second detection mode, and a third detection mode on the m*n light emitting diodes. In the first detection mode, when the level of any second connection line of the n second connection lines is opposite to the levels of the remaining n-1 second connection lines of the n second connection lines, the detection circuit sequentially detects the m first connection lines, and when the level of any first connection line of the m first connection lines is opposite to the levels of the remaining m-1 first connection lines of the m first connection lines, the detection circuit sequentially detects the n second connection lines. In the second detection mode, when the level of any second connection line is opposite to the levels of the remaining n-1 second connection lines of the n second connection lines, the detection circuit simultaneously detects the m first connection lines. In the third detection mode, when the level of any first connection line is opposite to the levels of the remaining m-1 first connection lines of the m first connection lines, the detection circuit simultaneously detects the n second connection lines, and in the third detection mode, the detection circuit simultaneously detects whether the current between the n second connection lines and the any first connection line is abnormal.

3. A method for detecting a light-emitting diode (LED) display panel, characterized in that, The light emitting diode display panel includes m*n light emitting diodes, where m and n are positive integers. The light emitting diode display panel detection method includes the following steps: m first connection lines, n second connection lines, and a detection circuit are provided, where each first connection line is coupled to the positive electrode of n light emitting diodes, and each second connection line is coupled to the negative electrode of m light emitting diodes; and The detection circuit selectively performs at least one of a first detection mode, a second detection mode, and a third detection mode on the m*n light emitting diodes; In the first detection mode, when any second connection line of the n second connection lines is activated, the detection circuit sequentially detects the m first connection lines. When the level of any first connection line of the m first connection lines is opposite to the levels of the remaining m-1 first connection lines of the m first connection lines, the detection circuit sequentially detects the n second connection lines. In the second detection mode, when the level of any second connection line is opposite to the levels of the remaining n-1 second connection lines of the n second connection lines, the detection circuit simultaneously detects the m first connection lines. In the third detection mode, when the level of any first connection line is opposite to the levels of the remaining m-1 first connection lines of the m first connection lines, the detection circuit simultaneously detects the n second connection lines. When the detection circuit performs the first detection mode, the abnormal conditions that can be detected by the detection circuit include open circuit, short circuit between any first connection line and its adjacent first connection line, short circuit between any second connection line and its adjacent second connection line, excessively high resistance of any light emitting diode or its connection path in the m*n light emitting diodes, and excessively high resistance of any second connection line.

4. A method for detecting a light-emitting diode (LED) display panel, characterized in that, The light emitting diode display panel includes m*n light emitting diodes, where m and n are positive integers. The light emitting diode display panel detection method includes the following steps: m first connection lines, n second connection lines, and a detection circuit are provided, where each first connection line is coupled to the positive electrode of n light emitting diodes, and each second connection line is coupled to the negative electrode of m light emitting diodes; and The detection circuit selectively performs at least one of a first detection mode, a second detection mode, and a third detection mode on the m*n light emitting diodes; In the first detection mode, when any second connection line of the n second connection lines is activated, the detection circuit sequentially detects the m first connection lines. When the level of any first connection line of the m first connection lines is opposite to the levels of the remaining m-1 first connection lines of the m first connection lines, the detection circuit sequentially detects the n second connection lines. In the second detection mode, when the level of any second connection line is opposite to the levels of the remaining n-1 second connection lines of the n second connection lines, the detection circuit simultaneously detects the m first connection lines. In the third detection mode, when the level of any first connection line is opposite to the levels of the remaining m-1 first connection lines of the m first connection lines, the detection circuit simultaneously detects the n second connection lines. When the detection circuit performs the first detection mode, the abnormal conditions that can be detected by the detection circuit include open circuit, short circuit between any first connection line and its adjacent first connection line, short circuit between any second connection line and its adjacent second connection line, excessively high resistance of any light emitting diode or its connection path in the m*n light emitting diodes, and excessively high resistance of any second connection line. In the first detection mode, when the level of any one of the n second connection lines is opposite to the levels of the remaining n-1 second connection lines, the detection circuit sequentially detects the m first connection lines, and when the level of any one of the m first connection lines is opposite to the levels of the remaining m-1 first connection lines, the detection circuit sequentially detects the n second connection lines; in the second detection mode, when the level of any one of the n second connection lines is opposite to the levels of the remaining n-1 second connection lines, the detection circuit simultaneously detects the m first connection lines; in the third detection mode, when the level of any one of the m first connection lines is opposite to the levels of the remaining m-1 first connection lines, the detection circuit simultaneously detects the n second connection lines. When the detection circuit executes the second detection mode, the abnormal conditions that the detection circuit can detect include open circuit, short circuit between any one of the first connection lines and any one of the second connection lines, short circuit between any one of the second connection lines and its adjacent second connection line, too high resistance of any one of the m*n light emitting diodes or its connection path, and too high resistance of any one of the second connection lines.

5. A method for detecting a light-emitting diode (LED) display panel, characterized in that, The light emitting diode display panel includes m*n light emitting diodes, where m and n are positive integers. The light emitting diode display panel detection method includes the following steps: providing m first connection lines, n second connection lines, and a detection circuit, where each first connection line is coupled to the positive electrode of n light emitting diodes, and each second connection line is coupled to the negative electrode of m light emitting diodes; and the detection circuit selectively executes at least one of a first detection mode, a second detection mode, and a third detection mode on the m*n light emitting diodes. wherein, in the first detection mode, when a level of any one of the n second connection lines is opposite to levels of the remaining n-1 second connection lines of the n second connection lines, the detection circuit sequentially detects the m first connection lines, and when a level of any one of the m first connection lines is opposite to levels of the remaining m-1 first connection lines of the m first connection lines, the detection circuit sequentially detects the n second connection lines; in the second detection mode, when the level of any one of the n second connection lines is opposite to the levels of the remaining n-1 second connection lines of the n second connection lines, the detection circuit simultaneously detects the m first connection lines; in the third detection mode, when the level of any one of the m first connection lines is opposite to the levels of the remaining m-1 first connection lines of the m first connection lines, the detection circuit simultaneously detects the n second connection lines, and when the detection circuit performs the third detection mode, the abnormal conditions that the detection circuit can detect include open circuit, short circuit between the any one of the m first connection lines and the any one of the n second connection lines, short circuit between the any one of the m first connection lines and its adjacent first connection line, too high resistance of any one of the m*n light emitting diodes or its connection path, and too high resistance of the any one of the n second connection lines.

6. A device for detecting a light-emitting diode (LED) display panel, used to detect an LED display panel, characterized in that, The light emitting diode display panel includes m*n light emitting diodes, where m and n are positive integers, and the light emitting diode display panel detection device includes: m first connection lines, each of which is coupled to anodes of n light emitting diodes; n second connection lines, each of which is coupled to cathodes of m light emitting diodes; and a detection circuit configured to selectively perform at least one of a first detection mode, a second detection mode, and a third detection mode on the m*n light emitting diodes, wherein, in the first detection mode, when a level of any one of the n second connection lines is opposite to levels of the remaining n-1 second connection lines of the n second connection lines, the detection circuit sequentially detects the m first connection lines, and when a level of any one of the m first connection lines is opposite to levels of the remaining m-1 first connection lines of the m first connection lines, the detection circuit sequentially detects the n second connection lines; in the second detection mode, when the level of any one of the n second connection lines is opposite to the levels of the remaining n-1 second connection lines of the n second connection lines, the detection circuit simultaneously detects the m first connection lines; in the third detection mode, when the level of any one of the m first connection lines is opposite to the levels of the remaining m-1 first connection lines of the m first connection lines, the detection circuit simultaneously detects the n second connection lines. The light emitting diode display panel includes m*n light emitting diodes, where m and n are positive integers, and the light emitting diode display panel detection device includes:

7. A device for detecting a light-emitting diode (LED) display panel, used to detect an LED display panel, characterized in that, m first connection lines, each of which is coupled to anodes of n light emitting diodes; n second connection lines, each of which is coupled to cathodes of m light emitting diodes; and a detection circuit configured to selectively perform at least one of a first detection mode, a second detection mode, and a third detection mode on the m*n light emitting diodes, wherein, in the first detection mode, when a level of any one of the n second connection lines is opposite to levels of the remaining n-1 second connection lines of the n second connection lines, the detection circuit sequentially detects the m first connection lines, and when a level of any one of the m first connection lines is opposite to levels of the remaining m-1 first connection lines of the m first connection lines, the detection circuit sequentially detects the n second connection lines; in the second detection mode, when the level of any one of the n second connection lines is opposite to the levels of the remaining n-1 second connection lines of the n second connection lines, the detection circuit simultaneously detects the m first connection lines; in the third detection mode, when the level of any one of the m first connection lines is opposite to the levels of the remaining m-1 first connection lines of the m first connection lines, the detection circuit simultaneously detects the n second connection lines. A detection circuit is configured to selectively perform at least one of a first detection mode, a second detection mode, and a third detection mode on the m*n LEDs. In the first detection mode, when a level of any one of the n second connection lines is opposite to levels of the remaining n-1 second connection lines, the detection circuit sequentially detects the m first connection lines, and when a level of any one of the m first connection lines is opposite to levels of the remaining m-1 first connection lines, the detection circuit sequentially detects the n second connection lines. In the second detection mode, when a level of any one of the n second connection lines is opposite to levels of the remaining n-1 second connection lines, the detection circuit simultaneously detects the m first connection lines. In the third detection mode, when a level of any one of the m first connection lines is opposite to levels of the remaining m-1 first connection lines, the detection circuit simultaneously detects the n second connection lines. In the third detection mode, the detection circuit simultaneously detects whether a current between the n second connection lines and any one of the m first connection lines is abnormal.

8. A device for detecting a light-emitting diode (LED) display panel, used to detect an LED display panel, characterized in that, The LED display panel includes m*n LEDs, where m and n are positive integers. The LED display panel detection device includes: m first connection lines, each of which is coupled to anodes of n LEDs; n second connection lines, each of which is coupled to cathodes of m LEDs; and a detection circuit configured to selectively perform at least one of a first detection mode, a second detection mode, and a third detection mode on the m*n LEDs. In the first detection mode, when a level of any one of the n second connection lines is opposite to levels of the remaining n-1 second connection lines, the detection circuit sequentially detects the m first connection lines, and when a level of any one of the m first connection lines is opposite to levels of the remaining m-1 first connection lines, the detection circuit sequentially detects the n second connection lines. In the second detection mode, when a level of any one of the n second connection lines is opposite to levels of the remaining n-1 second connection lines, the detection circuit simultaneously detects the m first connection lines. In the third detection mode, when a level of any one of the m first connection lines is opposite to levels of the remaining m-1 first connection lines, the detection circuit simultaneously detects the n second connection lines. When the detection circuit performs the first detection mode, the detection circuit can detect abnormal conditions including an open circuit, a short circuit between any one of the m first connection lines and its adjacent first connection line, a short circuit between any one of the n second connection lines and its adjacent second connection line, an excessively high resistance of any one of the m*n LEDs or its connection path, and an excessively high resistance of any one of the n second connection lines. ​ 9. A device for detecting a light-emitting diode (LED) display panel, used to detect an LED display panel, characterized in that, The light emitting diode display panel includes m*n light emitting diodes, where m and n are positive integers. The light emitting diode display panel detection device includes: m first connection lines, each of which is coupled to the anodes of n light emitting diodes; n second connection lines, each of which is coupled to the cathodes of m light emitting diodes; and a detection circuit configured to selectively perform at least one of a first detection mode, a second detection mode, and a third detection mode on the m*n light emitting diodes. In the first detection mode, when the level of any one of the n second connection lines is opposite to the levels of the remaining n-1 second connection lines, the detection circuit sequentially detects the m first connection lines, and when the level of any one of the m first connection lines is opposite to the levels of the remaining m-1 first connection lines, the detection circuit sequentially detects the n second connection lines. In the second detection mode, when the level of any one of the n second connection lines is opposite to the levels of the remaining n-1 second connection lines, the detection circuit simultaneously detects the m first connection lines. In the third detection mode, when the level of any one of the m first connection lines is opposite to the levels of the remaining m-1 first connection lines, the detection circuit simultaneously detects the n second connection lines. When the detection circuit performs the second detection mode, the abnormal conditions that can be detected by the detection circuit include open circuit, short circuit between any one of the first connection lines and any one of the second connection lines, short circuit between any one of the second connection lines and its adjacent second connection line, excessively high resistance of any one of the light emitting diodes or its connection path, and excessively high resistance of any one of the second connection lines. The light emitting diode display panel includes m*n light emitting diodes, where m and n are positive integers. The light emitting diode display panel detection device includes:

10. A device for detecting a light-emitting diode (LED) display panel, used to detect an LED display panel, characterized in that, m first connection lines, each of which is coupled to the anodes of n light emitting diodes; n second connection lines, each of which is coupled to the cathodes of m light emitting diodes; and a detection circuit configured to selectively perform at least one of a first detection mode, a second detection mode, and a third detection mode on the m*n light emitting diodes. In the first detection mode, when the level of any one of the n second connection lines is opposite to the levels of the remaining n-1 second connection lines, the detection circuit sequentially detects the m first connection lines, and when the level of any one of the m first connection lines is opposite to the levels of the remaining m-1 first connection lines, the detection circuit sequentially detects the n second connection lines. In the second detection mode, when the level of any one of the n second connection lines is opposite to the levels of the remaining n-1 second connection lines, the detection circuit simultaneously detects the m first connection lines. In the third detection mode, when the level of any one of the m first connection lines is opposite to the levels of the remaining m-1 first connection lines, the detection circuit simultaneously detects the n second connection lines. When the detection circuit performs the second detection mode, the abnormal conditions that can be detected by the detection circuit include open circuit, short circuit between any one of the first connection lines and any one of the second connection lines, short circuit between any one of the second connection lines and its adjacent second connection line, excessively high resistance of any one of the light emitting diodes or its connection path, and excessively high resistance of any one of the second connection lines. ​ In the first detection mode, when the level of any one of the n second connection lines is opposite to the levels of the remaining n-1 second connection lines, the detection circuit sequentially detects the m first connection lines, and when the level of any one of the m first connection lines is opposite to the levels of the remaining m-1 first connection lines, the detection circuit sequentially detects the n second connection lines. In the second detection mode, when the level of any one of the n second connection lines is opposite to the levels of the remaining n-1 second connection lines, the detection circuit simultaneously detects the m first connection lines. In the third detection mode, when the level of any one of the m first connection lines is opposite to the levels of the remaining m-1 first connection lines, the detection circuit simultaneously detects the n second connection lines. When the detection circuit executes the third detection mode, the abnormal conditions that the detection circuit can detect include open circuit, short circuit between any one of the first connection lines and any one of the second connection lines, short circuit between any one of the first connection lines and its adjacent first connection line, too high resistance of any one of the m*n light emitting diodes or its connection path, and too high resistance of any one of the second connection lines.

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