JPH1078466A - Apparatus and method for inspection of liquid-crystal display device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an apparatus and a method, for the inspection of a liquid- crystal display device, by which the value of a power-supply current supplied to a liquid-crystal display module from a power-supply circuit can be detected in a short time and with good accuracy. SOLUTION: A current detection circuit 3 measures the current value of a driving current supplied from a power-supply-voltage generation circuit 28 to a liquid-crystal display module 21 which is composed of a liquid-crystal display panel 22, of a scanning-electrode drive circuit 23 and of a signal- electrode drive circuit 24. At this time, a scanning-timing signal which is used to drive the liquid-crystal display module 21 is output to the scanning- electrodeldrive circuit 23, and the current value of the driving current supplied to the liquid-crystal display module 21 is measured on the basis of a V- synchronizing signal related to the scanning-timing signal.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an inspection method and an inspection apparatus for a liquid crystal display, and more particularly, to an inspection apparatus for a liquid crystal display which measures a value of a power supply current supplied to a liquid crystal display module in the liquid crystal display. And inspection methods.

[0002]

2. Description of the Related Art Recently, liquid crystal display devices have been widely used as displays for TVs, personal computers, etc. because of their advantages such as thin and light weight, low voltage drive, and low power consumption.

Conventionally, as a method for detecting a power supply current supplied to a liquid crystal display module in the liquid crystal display device, for example, the following method has been adopted.

A detection resistor is connected in series in a current path between the power supply circuit and the liquid crystal display module, and a voltage between both ends of the detection resistor is measured by, for example, an integrating A / D converter to detect a power supply current. Was. Here, the power supply current flowing through the detection resistor changes periodically, for example, as shown in FIG. Therefore, the sampling period is made sufficiently long so that the change point can be ignored with respect to the period of the current.
The interval integration shown in (1) was performed. Also, a method of performing a stable current detection by smoothing an output voltage through a smoothing circuit such as a filter without directly performing an integration operation on the output voltage and integrating the smoothed voltage. Has also been proposed.

[0005]

However, in the conventional power supply current measuring method, as described above, a method of setting a sufficiently long sampling period for a periodic change of the current and a method of smoothing the output voltage are used. In the method of measuring the applied voltage, an instantaneous overcurrent as shown by P in FIG. 4 cannot be detected, so that there is a problem that an accurate power supply current cannot be measured. Further, since the sampling period is long, there is a problem that a long measurement time is required. SUMMARY OF THE INVENTION The present invention has been made in view of the above problems, and provides an inspection apparatus and an inspection method for a liquid crystal display device capable of detecting a value of a power supply current supplied from a power supply circuit to a liquid crystal display module in a short time and accurately. Its purpose is to provide.

[0006]

According to the first aspect of the present invention,
An inspection device for a liquid crystal display device for measuring a current value of a power supply current supplied from a power supply circuit to a liquid crystal display module including a liquid crystal display panel and a drive circuit for driving the liquid crystal display panel, the liquid crystal display module being driven. And a current measuring means for measuring a current value of a power supply current supplied to the liquid crystal display module based on a signal related to the timing signal. Solve.

That is, according to the first aspect of the present invention,
In order to drive the liquid crystal display module in an inspection apparatus for a liquid crystal display device for measuring a current value of a power supply current supplied from a power supply circuit to a liquid crystal display module comprising a liquid crystal display panel and a drive circuit for driving the liquid crystal display panel Is output to the drive circuit, and the current value of the power supply current supplied to the liquid crystal display module is measured based on the signal related to the timing signal.

Therefore, the current value of the power supply current supplied from the power supply circuit to the liquid crystal display module is measured based on a signal relating to a timing signal for driving the liquid crystal display module. Good detection is possible.

In this case, the current measuring means outputs a detection voltage corresponding to a power supply current supplied from the power supply circuit to the liquid crystal display module. A measurement control unit that outputs a switch switching control signal at a timing corresponding to a signal related to the timing signal; and the detection voltage based on the switching switching control signal output from the measurement control unit; An output switching means for switching and outputting a reference voltage having a polarity opposite to a voltage, and a comparing and integrating means for integrating an output of the output switching means to obtain an integrated voltage and outputting a comparison signal according to the integrated voltage Counting means for counting a basic clock based on a comparison signal output from the comparison and integration means and outputting a count value; It may be composed by a display means for displaying a count value output from the stage as the current value of the source current.

That is, according to the second aspect of the present invention,
In the invention according to claim 1, the current measuring means includes a current-voltage converting means, a measuring control means, an output switching means, a comparing and integrating means, a counting means, and a display means, and The current-voltage conversion means outputs a detection voltage corresponding to a power supply current supplied to the liquid crystal display module from the power supply circuit, and the measurement control means outputs a switch switching control signal at a timing according to a signal related to a timing signal. An output switching unit that switches and outputs the detection voltage and a reference voltage having a polarity opposite to the detection voltage based on the switching switching control signal output from the measurement control unit; The output of the switching means is integrated to obtain an integrated voltage, a comparison signal is output in accordance with the integrated voltage, and the counting means outputs the comparison signal to the comparison signal output from the comparison and integration means. And Zui, and outputs a count value by counting the basic clock, the display means displays the count value output from the counting means as a current value of the source current.

Therefore, in addition to the effect of the first aspect of the present invention, the current value of the power supply current supplied from the power supply circuit to the liquid crystal display module can be detected in a short time and accurately with a simple circuit configuration. It becomes possible.

According to a third aspect of the present invention, there is provided a liquid crystal display device for measuring a current value of a power supply current supplied from a power supply circuit to a liquid crystal display module comprising a liquid crystal display panel and a drive circuit for driving the liquid crystal display panel. And outputting a timing signal for driving the liquid crystal display module to the drive circuit, and a current value of a power supply current supplied to the liquid crystal display module based on a signal related to the timing signal. The above-mentioned problem is solved by measuring.

That is, according to the third aspect of the present invention,
In a method for testing a liquid crystal display device for measuring a current value of a power supply current supplied from a power supply circuit to a liquid crystal display module including a liquid crystal display panel and a driving circuit for driving the liquid crystal display panel, the method for driving the liquid crystal display panel The above object is achieved by outputting a timing signal to the drive circuit and measuring a current value of a power supply current supplied to the liquid crystal display module based on a signal related to the timing signal.

Therefore, since the current value of the power supply current supplied from the power supply circuit to the liquid crystal display module is measured based on the signal relating to the timing signal for driving the liquid crystal display module, the accuracy is reduced in a short time. Good detection is possible.

According to the fourth aspect of the present invention, a liquid crystal for measuring a current value of a power supply current supplied from a power supply circuit to a liquid crystal display module including a liquid crystal display panel and a drive circuit for driving the liquid crystal display panel. A method for testing a display device, comprising: outputting a timing signal for driving the liquid crystal display module to the drive circuit; and detecting a detection voltage corresponding to a power supply current supplied from the power supply circuit to the liquid crystal display module. Outputting the signal, outputting a switch switching control signal at a timing corresponding to the signal related to the timing signal, and, based on the switching switching control signal, the detected voltage and the detected voltage have opposite polarities. Switching between a reference voltage and outputting as a switching voltage; and integrating the switching voltage to obtain an integrated voltage. And outputting a comparison signal in response to the integrated voltage, based on the comparison signal, and outputting a count value by counting the basic clock,
And displaying the count value as a current value of the power supply current.

That is, according to the fourth aspect of the present invention,
In a method for inspecting a liquid crystal display device for measuring a current value of a power supply current supplied from a power supply circuit to a liquid crystal display module including a liquid crystal display panel and a driving circuit for driving the liquid crystal display panel, the method for driving the liquid crystal display module A timing signal is output to the drive circuit, a detection voltage corresponding to a power supply current supplied from the power supply circuit to the liquid crystal display module is output, and a switch switching control signal is output at a timing according to a signal related to the timing signal. Based on a switching switching control signal, switches between a detection voltage and a reference voltage having a polarity opposite to the detection voltage, outputs the switching voltage, and integrates the switching voltage to obtain an integrated voltage; And outputs a count value by counting the basic clock based on the comparison signal. , Displays the count value as a current value of the supply current.

Accordingly, the configuration is such that the current value of the power supply current supplied to the liquid crystal display module from the power supply circuit is measured based on a signal relating to a timing signal for driving the liquid crystal display module, and therefore, a simple circuit configuration is used. , For a short time,
In addition, detection can be performed with high accuracy.

[0018]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A preferred embodiment to which a detection circuit and a detection method of a liquid crystal display device according to the present invention are applied will be described below with reference to the drawings. 1 to 3 are diagrams for explaining an inspection system for a liquid crystal display device according to the present embodiment.

FIG. 1 is a block diagram showing a circuit configuration of a current detection system 1 of a liquid crystal display device to which the present invention is applied. The detection system 1 of the liquid crystal display device includes a liquid crystal display device 2 and a current detection circuit 3. It is composed of

The liquid crystal display device 2 comprises, for example, a TFT liquid crystal display panel 22, a scanning electrode driving circuit 23, a signal electrode driving circuit 24, a power supply voltage generating circuit 28, and the like. On a glass substrate of the panel 22, an IC chip having the above-described scanning electrode drive circuit 23 and an IC chip having the signal electrode drive circuit 24 are directly mounted (Chip On Glass type), and the liquid crystal display module 2
2 are formed.

The liquid crystal display panel 22 employs, for example, an active matrix type of TFT, in which scanning lines (gate lines) Xn and signal lines (drain lines) Ym are arranged in a matrix.
A TFT is provided at each intersection of the scanning line Xn and the signal line Ym.
(A thin film transistor) and a pixel having a liquid crystal capacitance formed by connecting a pixel electrode to the source side of the switching element. In the liquid crystal display panel 22, the scanning line driving circuit 23 and the signal electrode driving circuit 24 sequentially drive the scanning line Xn and the signal line Ym, and the video signal is supplied to the liquid crystal capacitance and the like of each pixel sequentially selected. Is applied and the charge is held, whereby the video signal is displayed.

The scan electrode drive circuit 23 comprises a shift register, a gate circuit, and the like, and has a scan timing signal supplied from the timing signal generation circuit 31 in the current detection circuit 3 and a scan power supply supplied from the power supply voltage generation circuit 28. A scanning signal is generated based on the voltage VD and applied to a predetermined scanning line Xn in the liquid crystal display panel 22 to selectively drive.

The signal electrode drive circuit 24 comprises a shift register, a sample hold circuit, a level shifter circuit, a gate circuit, and the like. The display timing signal supplied from the timing signal generation circuit 31 and the power supply voltage generation circuit 2
8 to generate a display signal based on the signal power supply voltage VD supplied from the signal line Ym.
Are sequentially applied.

The power supply voltage generation circuit 28 generates a scanning power supply voltage VG and a signal power supply voltage VD for driving the liquid crystal display panel 22, and generates a scanning electrode driving circuit 23 and a signal electrode driving circuit in the liquid crystal display module 21. Output to the circuit 24 respectively.

Next, the configuration of the current detection circuit 3 will be described.
As the current detection circuit 3, an integration type AD converter is used, and the value of the power supply current based on the scanning power supply voltage VG output from the power supply voltage generation circuit 28 to the scan electrode drive circuit 23 in the liquid crystal display module 21. Has the function of measuring The current detection circuit 3 includes, for example, a synchronization signal generation circuit 30, a timing signal generation circuit 31, a switch circuit 32, a controller 33, an integration circuit 34, a counter circuit 35, a display 36, and the like.

The synchronizing signal generating circuit 30 generates a horizontal (H) synchronizing signal and outputs it to the timing signal generating circuit 31, and also generates a vertical (V) synchronizing signal and outputs it to the timing signal generating circuit 31 and the controller 33. I do.

The timing signal generating circuit 31 generates a scanning timing signal and a display timing signal based on the horizontal synchronizing signal and the vertical synchronizing signal input from the synchronizing signal generating circuit 30, respectively. Output to the drive circuit 24. Here, in the scanning timing signal, the vertical synchronization signal becomes a start pulse,
The horizontal synchronizing signal becomes a clock.

The current detecting resistor R1 is connected in series between the power supply voltage generating circuit 28 and the scan electrode driving circuit 23. One end of the current detecting resistor R1 is grounded and the other end is connected to the power supply voltage generating circuit 28. A detection voltage Ex that is proportional to the power supply current flowing through the current detection resistor R1 is output by the scanning power supply voltage VG output from. It is preferable that the current detecting resistor R1 has a small impedance to reduce a voltage drop.

The switch circuit 32 switches the output voltage to the integration circuit 34, and switches the connection of the switch SW between the T1 terminal and the T2 terminal based on a switching control signal supplied from the controller 33. T1
The detection voltage Ex is output from the terminal, and from the T2 terminal,
A reference voltage Es having a polarity opposite to that of the detection voltage Ex is output. In other words, when the switching switching control signal is at the “H” level, the switch SW is connected to the T1 terminal and the voltage Es is output to the integration circuit 34 at the subsequent stage, while when the switching control signal is at the “L” level. The switch SW is connected to the T1 terminal, and the reference voltage Es is output to the integration circuit 34 at the subsequent stage.

The controller 33 includes a synchronization signal generation circuit 3
The switching circuit 3 generates a switching control signal at a timing corresponding to a vertical (V) synchronization signal inputted from 0, and
The switching timing of the second switch SW is controlled. Also,
The controller 33 includes a zero-cross comparator COMP.
Counter circuit 35 based on the comparison signal input from
Control the counting operation.

The integrating circuit 34 includes a resistor R2, a capacitor C, and an operational amplifier OP. The integration circuit 34 integrates the input voltage with a time constant determined by the product R2 · C of the resistor R2 and the capacitor C to generate an integrated voltage Vi,
Output to the next stage zero-cross comparator COMP. The integration circuit 34 performs integration in the positive voltage direction when the input is the detection voltage Ex, and performs integration in the zero voltage direction when the input is the reference voltage Es.

The zero-cross comparator COMP outputs a comparison signal to the controller 33 in accordance with the integration voltage Vi input from the integration circuit 34. Specifically, when the input integration voltage Vi becomes higher than the ground potential, An "H" level signal is output as a comparison signal, and when the integrated voltage Vi becomes equal to zero (ground potential), "L" is output as the comparison signal.
Output level signal.

The counter circuit 35 counts the number of basic clocks input from the basic clock generator 37 in accordance with an instruction from the controller 33, and outputs the obtained count value to the display 36. The display 36 displays the count value input from the counter circuit 35 as the current value of the power supply current.

Next, the operation of this embodiment will be described with reference to FIGS.
This will be described based on the waveform diagram of the signal of the current detection device 3 shown in FIG. First, the operation of the liquid crystal display device 1 is as follows.

Synchronous signal generation circuit 30 in current detection circuit 3
, A horizontal (H) synchronizing signal and a vertical (V) synchronizing signal are output to the timing signal generating circuit 31, and from the timing signal generating circuit 31, the scanning timing is determined based on the input horizontal synchronizing signal and vertical synchronizing signal. A signal and a display timing signal are generated, and the liquid crystal display module 2
1 scan electrode drive circuit 23 and signal electrode drive circuit 24
Is output to

The scanning electrode driving circuit 23 generates a scanning signal based on the scanning power supply voltage VG input from the power supply voltage generating circuit 28 and the scanning timing signal input from the timing signal generating circuit 31, and generates a scanning signal. 2
2 scan lines Xn are selectively driven, and the signal electrode drive circuit 24 includes the display power supply voltage VD input from the power supply voltage generation circuit 28 and the timing signal generation circuit 3.
A display signal is generated based on the display timing signal input from the LCD 1 and the signal line Ym of the liquid crystal display panel 22 is generated.
Are sequentially driven. As a result, in the liquid crystal display panel 22,
A display signal corresponding to the video signal is applied to the liquid crystal capacitance or the like of each pixel that is sequentially selected, and the video signal is displayed.

The operation of the current detecting device 2 is as follows.

The detection (sampling) of the power supply current supplied from the power supply voltage generation circuit 28 to the scan electrode drive circuit 23 in the liquid crystal display module 21 is performed by detecting the power supply current flowing through the current detection resistor R1 connected in series between the two circuits. Is performed by measuring the value of the detection voltage Ex corresponding to.

First, the scanning power supply voltage VG output from the power supply voltage generating circuit 28 is supplied from one end of the current detection resistor R1.
As a result, a detection voltage Ex proportional to the power supply current generated in the current detection resistor R1 is output to the T1 terminal. Here, the current flowing through the current detection resistor R1 changes, for example, in a V synchronization cycle as shown in FIG. This is because, in order to drive the liquid crystal display panel 22 in V cycle units, the connection with the scanning lines Xn group (load) is switched in V synchronization cycle, and the power supply current fluctuates.

In the controller 33, for example, as shown in FIG.
A switch switching control signal that switches between “H” and “L” in the V synchronization cycle as shown in FIG.
2 is output.

The switch circuit 32 includes a controller 33
The switching of the connection of the switch SW is performed based on the switch switching control signal input from the switch SW. While the switch switching control signal is at the “H” level, the switch SW is connected to the T1 side and the detection voltage Ex is set at the subsequent stage. While output to the integration circuit 34, while the switching control signal is at the “L” level, the switch SW is connected to the T2 side and the reference voltage Es is applied to the integration circuit 3
4 is output.

In the integration circuit 34, as shown in FIG. 3A, T is a V synchronization cycle period during which the detection voltage Ex is output.
During the period s, the integration operation in the positive voltage direction is performed, while the subsequent reference voltage Es is output (V synchronization cycle period), the integration operation in the zero voltage direction is performed, and the obtained integrated voltage V
i is output to the zero-cross comparator COMP. Here, as shown in FIG. 3A, as the integrated voltage Vi integrated in the positive voltage direction by the detection voltage Ex increases, the integrated voltage Vi is integrated by the reference voltage Es in the zero voltage direction.
Takes a time until the integrated voltage Vi becomes zero, and the time from the start of the integration operation in the zero voltage direction until the integrated voltage Vi becomes zero is defined as Tx.

In the zero-cross comparator COMP, as shown in FIG. 3B, when the integrated voltage Vi input from the integrating circuit 34 becomes zero (ground potential), an "L" level signal is used as a comparison signal. Output to the controller 33. For example, when an integrated voltage Vi as shown in FIG. 3A is output, a comparison signal as shown in FIG. 3B is output, and as shown in FIG. When such an integrated voltage Vi is output, a comparison signal as shown in FIG. 3B is output.

Further, the controller 33 causes the counter circuit 35 to execute the counting operation of the basic clock input from the basic clock oscillation circuit 27 based on the comparison signal input from the zero cross comparator COMP.
Here, as described above, the time during which the detection voltage Ex is connected and integrated is defined as a fixed time Ts, and the reference voltage Es having a polarity opposite to the detection voltage Ex is connected and integration is performed in the direction of zero voltage to perform integration. Assuming that the time until the voltage Vi becomes zero is Tx, the detection voltage Ex can be expressed by the following equation. Ex = (Es / Ts) × Tx (Equation) In the above equation, since the reference voltages Es and Ts are constant values, by counting the time of Tx by the counter circuit 35, the detection voltage Ex is obtained. A digital value proportional to is obtained. Therefore, in the controller 33, the counter circuit 34
Is counted for Tx. Specifically, as shown in FIG. 3C, the controller 33 sets the counter circuit 34 after Ts elapses after the comparison signal output from the zero-cross comparator COMP goes to the “H” level at the start of the integration operation. The counting operation is stopped when the comparison signal becomes "L" level, and the counter circuit 34 executes the counting operation only during Tx.

Since the count value counted by the count circuit 35 is proportional to the detection voltage Ex, it corresponds to the power supply current supplied to the scan electrode drive circuit 23 in the liquid crystal display module 21. This count value is output to the display 36. The display 36 displays this count value as the current value of the power supply current.

As described above, in the present embodiment, the power supply voltage generation circuit 28
In detecting the power supply current supplied to the scan electrode drive circuit 23 in the first circuit 1, the current detection resistor R1 outputs a detection voltage Ex corresponding to the power supply current supplied to the liquid crystal display module 21 from the power supply voltage generation circuit 28. , Controller 33
Outputs a switch switching control signal at a timing corresponding to a vertical control signal related to a scanning timing signal for driving the liquid crystal display panel 22. The switch circuit 32 outputs a switch switching control signal based on the switching switching control signal output from the controller 33. The detection voltage Ex and the reference voltage Es having the opposite polarity to the detection voltage Ex are switched and output as a switching voltage. The comparison circuit 34 integrates the output of the switching voltage to output an integrated voltage, and outputs a zero-cross comparator COMP. Outputs a comparison signal in accordance with the integrated voltage,
5 counts the basic clock output from the clock oscillation circuit 37 based on the comparison signal output from the COMP, and outputs a count value.
In this configuration, the count value input from the counter circuit 35 is displayed as the current value of the power supply current.

In other words, the power supply current is sampled and the current value of the power supply current is measured at the cycle timing of the vertical synchronizing signal which is a part of the scanning timing for driving the liquid crystal display panel 22 in the liquid crystal display module 21. Therefore, the power supply current can be detected by measuring one change cycle of the power supply current.

Therefore, the current value of the power supply current supplied from the power supply circuit to the liquid crystal display module can be accurately detected in a short time and with a simple circuit configuration.

In the above embodiment, the current detection circuit 3 is used to measure the power supply current supplied from the power supply voltage generation circuit 28 to the scan electrode drive circuit 23 in the liquid crystal display module 21. The present invention is not limited to this, and can be applied to the case where the power supply current supplied to the signal electrode drive circuit 24 is measured. In this case, a changeover switch is provided to connect the current detection circuit 21 between the power supply voltage generation circuit 28 and the scan electrode drive circuit 23, and when the current detection circuit 21 is connected between the power supply voltage generation circuit 28 and the signal electrode drive circuit 24. And the current supplied to each of the scan electrode drive circuit 23 and the signal electrode drive circuit 24 may be detected by one current detection circuit. Also,
In order to measure the power supply current supplied to the signal electrode drive circuit 24, a new current detection circuit may be provided, and a current detection circuit may be provided for each output stage where the power supply current is output.

In the above-described embodiment, the power supply current is sampled at a timing synchronized with the cycle of the V synchronization signal. However, the present invention is not limited to this, and other signals (for example, The power supply current may be sampled at the cycle timing of the horizontal synchronization signal).

In the above embodiment, the TFT active matrix driving method is used as the liquid crystal display panel. However, the present invention is not limited to this.
For example, an active matrix driving method using a metal insulat-or metal (MIM) diode or a simple matrix driving method may be used.

[0052]

As described above, according to the first aspect of the present invention, the current value of the power supply current supplied from the power supply circuit to the liquid crystal display module is determined by the timing signal for driving the liquid crystal display module. Since the measurement is performed based on the signal according to (1), the detection can be performed in a short time and with high accuracy.

According to the second aspect of the invention, in addition to the effect of the first aspect, the current value of the power supply current supplied from the power supply circuit to the liquid crystal display module can be reduced with a simple circuit configuration. The detection can be performed in a short time and with high accuracy.

According to the third aspect of the present invention, the value of the power supply current supplied from the power supply circuit to the liquid crystal display module is measured based on a signal relating to a timing signal for driving the liquid crystal display module. Since it is a configuration,
The detection can be performed in a short time and with high accuracy.

According to the fourth aspect of the present invention, the value of the power supply current supplied from the power supply circuit to the liquid crystal display module is measured based on a signal relating to a timing signal for driving the liquid crystal display module. Since it is a configuration,
With a simple circuit configuration, detection can be performed in a short time and with high accuracy.

[Brief description of the drawings]

FIG. 1 is a block diagram showing a circuit configuration of a current detection system of a liquid crystal display device according to an embodiment of the present invention.

FIG. 2 is a waveform diagram showing waveforms of a power supply current and a switching control signal in the current detection circuit of FIG. 1;

FIG. 3 shows an integrated voltage, a comparison signal,
FIG. 2 is a waveform diagram showing waveforms of a reference clock and a basic clock.

FIG. 4 is a diagram for explaining a conventional technique.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Inspection system of liquid crystal display device 2 Liquid crystal display device 3 Current inspection device 21 Liquid crystal display module 22 Liquid crystal display panel 23 Scan electrode drive circuit 24 Signal electrode drive circuit 28 Power supply voltage generation circuit 30 Synchronization signal generation circuit 31 Timing signal generation circuit 32 Switch Switching circuit 33 Controller 34 Integrating circuit 35 Counter circuit 36 Display 37 Basic clock generation circuit

Claims (4)

[Claims] An inspection apparatus for a liquid crystal display device for measuring a current value of a power supply current supplied from a power supply circuit to a liquid crystal display module including a liquid crystal display panel and a driving circuit for driving the liquid crystal display panel, A current measuring unit that outputs a timing signal for driving the liquid crystal display module to the drive circuit and that measures a current value of a power supply current supplied to the liquid crystal display module based on a signal related to the timing signal. An inspection apparatus for a liquid crystal display device. 2. A current-voltage converter for outputting a detection voltage corresponding to a power supply current supplied from the power supply circuit to the liquid crystal display module, a timing according to a signal related to the timing signal. so,
A measurement control unit that outputs a switch switching control signal; and, based on the switching switching control signal output from the measurement control unit, switching between the detection voltage and a reference voltage having a polarity opposite to the detection voltage. An output switching unit that integrates an output of the output switching unit to obtain an integrated voltage, and outputs a comparison signal in accordance with the integrated voltage; and a comparison signal output from the comparison and integration unit. hand,
2. A count means for counting a basic clock and outputting a count value, and display means for displaying a count value output from the count means as a current value of the power supply current. Inspection equipment for liquid crystal display devices. 3. A method for inspecting a liquid crystal display device for measuring a current value of a power supply current supplied from a power supply circuit to a liquid crystal display module comprising a liquid crystal display panel and a driving circuit for driving the liquid crystal display panel, A timing signal for driving the liquid crystal display module is output to the drive circuit, and a current value of a power supply current supplied to the liquid crystal display module is measured based on a signal related to the timing signal. Inspection method for liquid crystal display. 4. A method for inspecting a liquid crystal display device for measuring a current value of a power supply current supplied from a power supply circuit to a liquid crystal display module comprising a liquid crystal display panel and a drive circuit for driving the liquid crystal display panel, Outputting a timing signal for driving the liquid crystal display module to the drive circuit; outputting a detection voltage corresponding to a power supply current supplied to the liquid crystal display module from the power supply circuit; At the timing according to the signal,
Outputting a switch switching control signal, switching the detection voltage and a reference voltage having a polarity opposite to the detection voltage based on the switching switching control signal, and outputting the switching voltage as a switching voltage; To obtain an integrated voltage and output a comparison signal according to the integrated voltage; counting a basic clock based on the comparison signal and outputting a count value; Displaying the current value of the power supply current as a current value.