JP3441835B2 - Probe device - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a probe device of a type in which a plurality of probe needles are brought into contact with an electrode to be measured, and more particularly to a probe device in which the probe needles come into contact with an electrode to be measured. The present invention relates to a probe device provided with a contact sensor for detecting a contact. 2. Description of the Related Art FIG. 8A is a perspective view showing a part of a conventional probe device having a contact sensor.
This conventional example is an example of a probe device for inspecting a liquid crystal display panel, and includes a plurality of probe blocks. Each probe block 20 has a large number of probe needles 10 for measurement, and these probe needles 10 can contact the electrodes 12 on the liquid crystal display panel. Next to a group of these probe needles 10 is a pair of sensor needles 14 and 16.
Is provided. When the probe device is separated from the liquid crystal display panel, the sensor long hand 14 and the sensor short hand 16 are in contact with each other. When the probe device comes into contact with the liquid crystal display panel, the tip of the long sensor needle 14 comes in contact with the dummy electrode 18 on the liquid crystal display panel (or on a glass substrate on which no electrode is formed) and rises slightly. Then, the sensor long hand 14 separates from the sensor short hand 16 to interrupt the conduction between them, and this is electrically detected. Since the probe tip of the sensor long needle 14 and the probe tip of the probe needle 10 are at the same height, by detecting the above-mentioned conduction interruption, it is determined that the probe tip of the probe needle 10 has contacted the electrode 12 on the liquid crystal display panel. Can be detected. In the illustrated example, one contact sensor is provided for each probe block 20. However, in actuality, one contact sensor is attached to each end of each probe block 20 to adjust the parallelism of the probe block 20. It is also used for In another conventional example shown in FIG. 8B, two sensor needles 22 and 24 are in contact with the same dummy electrode 26 (see Japanese Patent Publication No. 2-108983). The height of the tip of the two sensor needles 22 and 24 is the same as the height of the tip of the probe needle 10. When the measurement probe needle 10 comes into contact with the electrode 12, the two sensor needles 22 and 24 also come into contact with the dummy electrode 26 at the same time, and the two sensor needles 22 and 24 conduct through the dummy electrode 26. . By electrically detecting the conduction, the contact of the probe needle 10 with the electrode 12 is detected. In the present invention, an optical contact sensor is used. As a related art, an optical contact sensor using an optical detection device for setting an origin of movement of a probe needle is known. (Japanese Patent Laid-Open No. 4-74)
976, JP-A-4-233481). In this conventional example, a movable slit member is arranged between the light emitting device and the light receiving device, and when any of a plurality of slits formed in the slit member comes between the light emitting device and the light receiving device. A signal is obtained. Thus, the origin of movement of the probe needle attached to the slit member can be determined at a plurality of locations. This conventional example is related to the present invention in that the position of the probe needle can be detected using a combination of the light emitting device and the light receiving device. However, the position of the probe needle in the Z direction can be determined only at the slit. It can only be checked, and cannot detect any moving position of the probe needle. Further, the method does not detect displacement of the probe needle when the probe needle comes into contact with the electrode. In each of the two conventional examples shown in FIG. 8, a contact detection signal is obtained only when the sensor needle is turned on or off. . That is, the contact detection signal is obtained
It is limited to the case where the probe device and the liquid crystal display panel are in a specific close state, and it is not possible to output a contact detection signal at an arbitrary overdrive amount after the probe needle contacts the electrode. . If the tip height of the sensor needle is changed, a contact detection signal can be output at an arbitrary overdrive amount, but in order to do so, the probe block must be rebuilt. Further, the two types of conventional examples shown in FIG. 8 each require a sensor needle separate from the probe needle for measurement, and a space for arranging the sensor needles is required. By the way, depending on the substrate to be measured, a large number of electrodes to be measured are densely arranged at the same pitch, and for such a substrate to be measured, there is no room to arrange a sensor needle other than a probe for measurement. There is also. In particular, FIG.
In the conventional example, a conductive dummy electrode is required separately from the LCD electrode, and if such a dummy electrode is used, the process efficiency of the liquid crystal display panel is deteriorated, and the pitch of the liquid crystal display panel is reduced and the space is reduced. Wiring will be hindered. Further, in two types of conventional examples shown in FIG.
Although contact is detected based on the presence or absence of electrical contact of the sensor needle, its reliability also poses a problem. In particular, in the conventional example of FIG. 8A, it has been confirmed that the contact portions of the pair of sensor needles 14 and 16 are deteriorated (oxidized, carbonized, adhered to dust, etc.), and the reliability is likely to be reduced. . SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems, and an object of the present invention is to make it possible to detect an arbitrary amount of overdrive on the probe needle side, and thereby to connect the probe needle to the electrode. An object of the present invention is to provide a probe device capable of detecting a contact. A probe device according to the present invention is a probe device of a type in which a plurality of probe needles are brought into contact with an electrode to be measured, wherein at least one of the plurality of probe needles is used. a shutter which is displaced according to the displacement, the contact sensor having a counter to disposed the light emitting device and light receiving device across the shutter, the receiving
Output contact signal based on output signal of optical device
A contact signal detection circuit. And luminescence
The cross-sectional area of the light passage area from the device to the light receiving device
And the output signal of the light receiving device
Changes according to the amount of light received by the light receiving device. The light emitting device and the light receiving device can be a combination of a light emitting diode and a phototransistor. The contact signal detecting circuit has two input terminals.
Output signal depending on the magnitude of the voltage input to the
An inverting comparator and a reference voltage circuit;
The output signal of the light receiving device is input to one input terminal of the comparator.
The reference voltage circuit is supplied to the other input terminal of the comparator.
Roads are connected. This reference voltage circuit is
Same as the light emitting device and the light receiving device included in the sensor
The reference side light emitting device and the reference side light receiving device
Light passage area from the reference side light emitting device to the reference side light receiving device
The cross-sectional area of the area is maintained constant and the reference
The reference voltage is output based on the output signal of the optical device. The shutter may be of a type that contacts the probe needle or may be fixed to the probe needle. When the probe needle comes into contact with the electrode to be measured and is displaced, the displacement is transmitted to the shutter. The amount of displacement of the shutter is detected as a change in the amount of light received by the light receiving device. The output voltage of the light receiving device changes according to the displacement of the probe needle. By inputting the output voltage of the light receiving device to the voltage comparison circuit,
If the reference value of the voltage comparison circuit is set to an arbitrary value, a contact detection signal can be obtained at an arbitrary overdrive amount after the probe needle comes into contact with the electrode to be measured. This contact detection signal can also be used as an overdrive limiter. Since this contact sensor acts directly on the probe needle for measurement, no special sensor needle is required, so that there is no need to take up the installation space for the sensor needle on the probe block side, and the measurement is performed on the substrate to be measured side. There is no need to provide a region other than the electrodes or a dummy electrode. Since this contact sensor employs an optical detection method, there is an advantage that electric noise which is detrimental to current measurement is not generated from the contact sensor. In the reference voltage circuit of the contact signal detecting circuit, if a light emitting device and a light receiving device having the same structure as that used for the contact sensor are used, even if the supply voltage of the contact signal detecting circuit fluctuates, the stable. Sensitivity characteristics can be maintained. FIG. 1 is a perspective view showing an embodiment of the present invention. This embodiment is a probe device for inspecting a liquid crystal display panel, and includes a plurality of probe blocks. FIG. 1 shows one of the probe blocks. The probe block 30 is provided with a number of probe needles 32 for measurement.
Contact sensors 34 are attached to the vicinity of both ends. The contact sensor 34 is fixed to the probe block 30 by mounting screws 36 and 37 so that the contact sensor 34 can be easily replaced. A wiring 38 is connected to the contact sensor 34. The sensor housing 42 is fixed with mounting screws 36, and the guide block 43 is fixed with mounting screws 37. The contact body 40 protruding below the contact sensor 34 is in contact with the probe needle 32, and can detect the vertical movement of the probe needle 32. The contact body 40 may be in contact with one probe needle or may be capable of contacting several probe needles. In this embodiment, two to four probe needles 3
The contact body 40 can come into contact with 2. This contact body 40
The probe needle 32 directly acts on the probe needle 32 for measurement.
Therefore, a dedicated sensor needle for the contact sensor is not required. FIG. 2 is a side sectional view of the contact sensor 34. A sensor housing 42 is fixed to the probe block 30 with a mounting screw, and a shutter 44 is slidably inserted into a through groove formed in the sensor housing 42. The shutter 44 can move up and down inside the through groove. The through-groove is open only on one side surface of the sensor housing 42, and the shutter 44 can be incorporated into the through-groove from this opening. After the shutter 44 is installed, the opening of the through groove can be covered with the guide block 43 (see FIG. 1). The contact body 40 is formed integrally with the lower end of the shutter 44,
The lower surface of the contact body 40 is in contact with the probe needle 32. The shutter 44 is always pushed downward by the action of the compression coil spring 46. On the other hand, an adjusting screw 48 is engaged with the upper end of the shutter 44, and the lower end of the adjusting screw 48 is in contact with the upper surface of the sensor housing 42. By adjusting the screwing amount of the adjusting screw 48, the lower limit position of the shutter 44 can be adjusted. A photocoupler including a light emitting element 54 and a light receiving element 56 is incorporated in the sensor housing 42. The light emitting element 54 and the light receiving element 56 face each other via the light passage hole 50 having a circular cross section. on the other hand,
The shutter 44 has a shutter hole 52 having a circular cross section. The light that has exited the light emitting element 54 passes through the light passage hole 50 and the shutter hole 52 before reaching the light receiving element 56.
The light receiving element 56 outputs a signal corresponding to the amount of received light. In this embodiment, a light emitting diode is used as the light emitting element 54 and a phototransistor is used as the light receiving element 56. Since the contact sensor 34 does not use a dedicated sensor needle, even if the contact sensor fails, it can be easily removed from the probe block 30 and replaced. On the other hand, in the conventional contact sensor, since the dedicated sensor needle is fixed to the probe block, it is necessary to replace the entire probe block or rebuild the sensor needle. The basic operation of the contact sensor 34 will be described. When the liquid crystal display panel 58 is separated from the probe needle 32, the shutter 44 is at the lower limit position. Even in this initial state, the contact body 40 is the probe needle 3
2 is in contact. That is, the lower limit position of the shutter 44 is adjusted in such a manner. In the initial state, the probe needle with which the contact body 40 is in contact and the other probe needles are all adjusted to have the same tip height. When the probe needle 32 contacts the electrode of the liquid crystal display panel 58, the probe needle 32 is displaced upward. In response, the shutter 44 is also displaced upward relative to the sensor housing 42, and a signal corresponding to the amount of displacement is output from the light receiving element 56. FIG. 3 is an explanatory diagram showing the operation of the contact sensor. FIG. 3A shows an initial state in which the probe needle 32 is separated from the liquid crystal display panel 58. The right side is a sectional side view of the shutter 44, and the left side is a front view of the shutter 44. At this time, the shutter 44 is at the lower limit position, and the contact body 40 of the shutter 44 is in contact with the probe needle 32. When viewed from the front, the light passage hole 50 and the shutter hole 52 of the photocoupler slightly overlap.
That is, only the lower end of the light passage hole 50 is slightly visible from the shutter hole 52. This overlapping portion becomes the light passage area 60, and the amount of light received by the light receiving element is determined according to the cross-sectional area of this area 60. FIG. 3B shows a state immediately after the liquid crystal display panel 58 is raised to bring its electrodes into contact with the probe needle 32. At this time, the probe needle 32 rises slightly, and the shutter 44 in contact with the probe needle 32 also rises by the same amount as the probe needle 32. Therefore, the light passage area 60 where the light passage hole 50 and the shutter hole 52 overlap is also enlarged, and the light receiving amount of the light receiving element is increased. FIG. 3C shows a state in which the liquid crystal display panel 58 is further raised to perform overdrive.
The displacement amount between the probe needle 32 and the shutter 44 also increases,
The cross-sectional area of the light passage area 60 further increases according to the amount of overdrive, and the amount of light received by the light receiving element further increases. FIG. 4 is a graph showing the output characteristics of the contact sensor. The horizontal axis indicates the overdrive amount, which means the amount of rise of the liquid crystal display panel from the time when the electrodes of the liquid crystal display panel contact the probe needle. The vertical axis indicates the amount of movement of the shutter and the output voltage of the light receiving element. The amount of movement of the shutter is a curve substantially proportional to the amount of overdrive. The reason for not being completely proportional is mainly due to the deflection of the probe needle. The curve of the output voltage of the light receiving element has a small slope when the overdrive amount is small, the slope increases as the overdrive amount increases, and decreases again when the overdrive amount further increases. The reason is that the cross-sectional area change of the light passage area with respect to the unit displacement of the shutter is larger when the upper end of the shutter hole is near the center of the light passage hole than when it is near the lower end or upper end of the light passage hole. Is larger. In a contact sensor having such output characteristics, a signal indicating that the probe needle has contacted an electrode of the liquid crystal display panel (hereinafter, referred to as a contact signal).
At an arbitrary overdrive amount. For example, if an attempt is made to output a contact signal when the overdrive amount reaches 20 μm, the output of the light receiving element is input to a comparator having a reference voltage equal to the output voltage corresponding to the overdrive amount. If
When the output signal of the comparator is inverted, it can be used as a contact signal. FIG. 5 is a circuit diagram showing an example of a contact signal detecting circuit for outputting a contact signal based on an output signal of a photocoupler. This detection circuit is roughly divided into a comparator 62, a measurement circuit 64 connected to the positive terminal side of the comparator 62, and a reference voltage circuit 66 connected to the negative terminal side of the comparator 62. The measurement circuit 64 includes a photocoupler 68 and a measurement-side potentiometer 70. The photocoupler 68 of the measuring circuit 64 is built in the contact sensor 34 of FIG. 2, and has an output characteristic as shown in FIG. On the other hand, the reference voltage circuit 66
Includes a reference-side photocoupler 69 and a reference-side potentiometer 71. The photocoupler 69 is incorporated in the reference contact sensor fixed in the state shown in FIG. The reference contact sensor does not contact the probe needle, and the shutter 44 is fixed to the sensor housing in the state shown in FIG. This reference contact sensor is mounted on a substrate including a contact signal detection circuit separately from the probe block. The reference voltage circuit 66 outputs a constant reference voltage set by the reference potentiometer 71. The comparator 62 outputs "High" when the measured voltage exceeds the reference voltage, and outputs "L" when the measured voltage is lower than the reference voltage.
ow "output. Therefore, if the potentiometer 71 of the reference voltage circuit 66 is adjusted to make the reference voltage equal to the contact sensor output voltage corresponding to the overdrive amount to be detected, the output of the comparator 62 is inverted at the target overdrive amount. Then, a contact signal is obtained. By the way, in the comparator 62, the output is inverted when the measured voltage exceeds the reference voltage. To invert the output, the measured voltage needs to be slightly higher than the reference voltage. The difference depends on the characteristics of the comparator. Generally, this difference is about 2 to 10 mV, which is 0.4 to 2.0 μm of the probe needle in the contact sensor of the present embodiment.
Corresponds to the displacement of This displacement amount is very small, and is sufficient as the detection sensitivity of the displacement of the probe needle. In FIG. 5, a reference voltage is generated by using a reference photocoupler 69 as the reference voltage circuit 66 for the following reason. As the reference voltage circuit 66, an ordinary constant voltage generation circuit that does not use a photocoupler can be used. However, in this case, when the voltage (+5 V) supplied to the detection circuit fluctuates, the output of the measurement circuit 64 is affected by the voltage fluctuation, but the output of the constant voltage generation circuit is not affected by the voltage fluctuation. Not affected. Therefore, the switching sensitivity changes due to the voltage fluctuation. On the other hand, when a reference voltage circuit using a photocoupler is used, the fluctuation of the supply voltage similarly affects the measurement circuit and the reference voltage circuit, and the switching sensitivity is kept constant. Such advantages are not limited to the effects of supply voltage fluctuations, and the effects of aging of the photocoupler are the same in the measurement circuit and the reference voltage circuit. As described above, by employing the same configuration for the measurement circuit and the reference voltage circuit, various error factors can be eliminated. If the state of the switching operation of the output of the comparator 62 shown in FIG. 5 can be displayed on the control panel of the probe device by the light emitting diode, the contact detection can be easily confirmed. Also, the parallel adjustment of the probe block can be performed using the contact sensors at both ends of the probe block. Although the circuit shown in FIG. 5 is an analog circuit, the detection circuit may be constituted by a digital circuit. When the probe needles of a plurality of probe blocks are brought into contact with the electrodes of the liquid crystal display panel at a time, the contact sensor of this embodiment can be used as follows. Raise the liquid crystal display panel to the position where all the contact sensors of each probe block output the contact signal. Based on this position, set the overdrive amount of the Z stage equipped with the liquid crystal display panel to the set value. Raise the Z stage.
This enables accurate control of the overdrive amount. The operation example described above is an example in which a "contact signal" is obtained based on the output of the contact sensor. However, this contact signal can be used as a limiter for overdrive. That is, since the contact sensor has the output characteristics shown in FIG. 4, if the reference voltage of the comparator is made equal to the output voltage corresponding to the desired overdrive amount required for the measurement, the desired overdrive At this point, the output signal of the comparator is inverted. In this case, a desired overdrive amount can be obtained only by using the contact sensor and the detection circuit without controlling the overdrive amount on the side of the Z stage on which the liquid crystal display panel is mounted. FIG. 6 schematically shows a pattern of a signal line (source line) 81 in a liquid crystal display panel. In an actual liquid crystal display panel, the signal lines 81
There are also gate lines orthogonal to the above, but their illustration is omitted. There are the following two methods for inspecting the quality of the signal line 81. In the first method, a test electrode is formed at one end 80 of the signal line 81, and the presence or absence of a short circuit between the signal lines is detected by bringing a probe needle into contact with a row of the test electrodes. Such an inspection method is performed when the pitch of the signal lines 81 (the interval between the signal lines) is relatively wide. In the second method, a test electrode is also formed at the other end 82 of the signal line 81, and the probe needle is brought into contact with the test electrode at both the one end 80 and the other end 82. Thereby, in addition to the short circuit between the signal lines, the disconnection of the signal line can be detected. When the pitch of the signal lines 81 becomes narrow, the signal lines 8
Because it is necessary to make 1 thinner and the risk of disconnection increases,
The necessity of implementing such a second inspection method increases.
By the way, each of the probe blocks of the probe device corresponds to each of the groups 84 and 86 of the signal lines 81. However, when the signal line groups 84 and 86 are closely arranged as shown in FIG. At the boundary 88 between the two groups 84 and 86, there is almost no extra space other than the arrangement of the signal line 81. In such a signal line pattern, if the probe needle is to be brought into contact with the test electrode at the other end 82, the probe block including the conventional contact sensor as shown in FIG. Cannot be ensured, so that inspection becomes impossible. On the other hand, in the probe block including the probe sensor of the present invention, no special space is required, so that the probe needle can be brought into contact with the test electrode at the other end 82 even with the signal line pattern as shown in FIG. FIG. 7 shows another embodiment of the present invention. FIG. 7A is a side sectional view of the contact sensor, and FIG.
(B) is a front view thereof. In this embodiment, a connecting member 74 is fixed to the lower end of the shutter 72.
Is adhered to the probe needle 32. Therefore, the compression coil spring 46 and the adjusting screw 48 in the embodiment of FIG. 2 are not necessary in this embodiment. The configuration and operation of other parts of this embodiment are the same as those of the embodiment of FIG. In the above description, a probe device for measuring a liquid crystal display panel has been described as an example, but the probe device of the present invention is not limited to a probe device for a liquid crystal display panel. According to the probe device of the present invention, since the displacement of the probe needle for measurement is directly received by the shutter, a dedicated sensor needle is not required, and the substrate to be measured is not limited to the electrode other than the measurement electrode. It is not necessary to provide a region or a dummy electrode. Further, since the contact sensor of this probe device employs an optical detection method, electric noise which is harmful to current measurement is not generated from the contact sensor. Furthermore, in the contact signal detection circuit, if a light emitting device and a light receiving device having the same structure as that used for the contact sensor are also used for the reference voltage circuit, stable sensitivity characteristics can be maintained.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a perspective view showing one embodiment of the present invention. FIG. 2 is a side sectional view of the contact sensor. FIG. 3 is an explanatory diagram showing an operation of the contact sensor. FIG. 4 is a graph showing output characteristics of a contact sensor. FIG. 5 is a circuit diagram of a contact signal detection circuit. FIG. 6 is a pattern of a test electrode. FIG. 7 is a side sectional view and a front view of a contact sensor according to another embodiment of the present invention. FIG. 8 is a perspective view of a conventional probe device with a contact sensor. [Description of Signs] 30 Probe block 32 Probe needle 34 Contact sensor 40 Contact body 42 Sensor housing 44 Shutter 46 Compression coil spring 48 Adjustment screw 50 Light passage hole 52 Shutter hole 54 Light emitting element 56 Light receiving element 58 Liquid crystal display panel

Continuation of the front page (56) References JP-A-6-140479 (JP, A) Japanese Utility Model Sho 62-134244 (JP, U) Japanese Utility Model Utility Model Sho 57-6012 (JP, U) (58) Fields investigated (Int) .Cl. ⁷ , DB name) G01R 1/06-1/073 G01R 31/26

Claims (1)

(57) [Claim 1] A probe device of the type in which a plurality of probe needles are brought into contact with an electrode to be measured has a probe having the following features.
Lobe equipment. (A) This probe device has a plurality of probe needles.
A system that is displaced in accordance with the displacement of at least one probe needle
And a shutter disposed opposite to the shutter.
A contact sensor having an optical device and a light receiving device;
Outputs a contact signal based on the output signal of the light receiving device
And a contact signal detection circuit. (B) a light passage area from the light emitting device to the light receiving device
When the cross-sectional area of the shutter changes according to the amount of displacement of the shutter.
The output signal of the light receiving device is
Will change accordingly. (C) The contact signal detection circuit has two input terminals.
Output signal is inverted according to the magnitude relationship of the voltage input to
And a reference voltage circuit.
The output signal of the light receiving device is input to one input terminal of
The reference voltage circuit is connected to the other input terminal of the comparator.
Connected. (D) The reference voltage circuit is included in the contact sensor.
Reference of the same structure as the light emitting device and the light receiving device to be inserted
A side light emitting device and a reference side light receiving device;
The cross-sectional area of the light passage area from the device to the reference side light receiving device
Is maintained constant, and the output of the reference side
Output a reference voltage based on the force signal.