JP2003139504A - Displacement sensor, its manufacturing method, and positioning stage - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a displacement sensor with little temperature drift and deterioration with the lapse of time and its manufacturing method, and a positioning stage with the displacement sensor attached to it. SOLUTION: The displacement sensor 1 has a strain gauge 10 provided with electrodes 14a-14d on one surface of a rectangular base material 11, a support member 12 supporting the base material 11, and a head member 13 fixed to a center part of the base material 11. The electrodes 14a-14d are provided in two portions with positive strain and two portions with negative strain in the base material when strain is generated in the base material 11 due to a relative positional change between the support member 12 and the head member 13. The electrodes 14a-14d are provided with large resistance by directly forming them as thin films on the base material 11 by a sputtering method. By this, voltage to be inputted in the strain gauge 10 is raised, a large output is provided, and sensitiveness of the strain gauge 10 can be enhanced.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a displacement sensor used for fine movement positioning, a manufacturing method thereof, and a positioning stage equipped with the displacement sensor.

[0002]

2. Description of the Related Art As a displacement sensor for measuring a minute displacement, one using a strain gauge is known. For example, in FIG.
10 is a perspective view showing a schematic structure of a displacement sensor 90 using strain gauges 94a to 94d, and FIG.
It is explanatory drawing which shows the connection circuit of a-94d. The displacement sensor 90 is provided on a base portion 91, a plate-shaped strain generating member 92 fixed to the base portion 91, a sensor head 93 attached to the strain generating material 92, and front and back surfaces of the strain generating material 92. Strain gauge 9
4a to 94d, and input / output terminals 98 of strain gauges 94a to 94d are provided on the base 91.

A metal plate or the like is used as the strain-generating material 92, and the strain gauges 94a to 94d are made of a Cu-Ni alloy or other metal foil 96 processed in a predetermined pattern on a resin base (plate) 95 such as polyimide. It has a structure attached with an adhesive. The metal foil 96 functions as a strain sensitive material. The strain gauges 94a to 94d are attached to the strain generating material 92 using an adhesive.

The resistance of the strain gauges 94a to 94d is set to R ₁ to
Let R ₄ be the strain generated in the strain gauges 94 a to 94 d by ε
_{1 to} ε ₄ and the resistance change amounts in the strain gauges 94 a to 94 d at that time are ΔR ₁ to ΔR ₄ , the relationship between the bridge input voltage Vin and the bridge output voltage Vout is expressed by the following equation (1). Here, K is a gauge factor.

[0005]

[Equation 1]

[0006] Since the sign of the strain epsilon ₂ and epsilon ₃ term is negative, the epsilon ₂ and epsilon ₃ itself is a negative distortion, the entire section code is four is positive strain ε ₁ ~ε ₄ All terms are added up. This increases the bridge output voltage Vout.
Further, it is understood that in order to increase the bridge output voltage Vout, if the strains ε _{1 to} ε ₄ are constant, the gauge factor K and the bridge input voltage Vin may be increased.

When the sensor head 93 is moved downward as shown by an arrow A in FIG. 9 with the base 91 fixed,
A warp occurs in the strain-flexing material 92, and strain gauges 94a and 94d
, The resistance becomes large, and the strain gauges 94b, 94c have small resistance. Therefore, the strain gauges 94a-9
By bridge-connecting 4d as shown in FIG. 10, it is possible to obtain an output voltage that is four times as large as that when only one strain gauge 94a is used. Reference numeral 97 shown in FIG. 9 is a correction resistor for achieving bridge balance. Also, FIG.
The relationship between the displacement amount of the sensor head 93 and the bridge output voltage is shown in FIG.

[0008]

However, in such a displacement sensor 90, the strain gauges 94a to 94d are attached to the strain generating member 92 using an adhesive. Therefore, when the elastic modulus of the adhesive is small, the strain is not sufficiently transmitted to the strain gauges 94a to 94d. On the contrary, the adhesive having a large elastic modulus is fragile and weak to heat. is there. Therefore, strain gauges 94a to 94d
When the adhesive layer is attached to the flexure material 92 using an adhesive, a temperature drift occurs due to the thickness of the adhesive layer, and the adhesive layer acts as a damper to reduce the sensitivity, and further the adhesive layer deteriorates with time. Due to the occurrence, it has been difficult to accurately measure the displacement amount. Also, the strain gauge 94a-
It is difficult to attach 94d to the front and back surfaces of the strain generating member 92 with high positional accuracy, and the thickness of the adhesive layer between the strain gauges 94a to 94d and the strain generating member 92 is set to be constant for each strain gauge 94a to 94d. Since it is difficult to do so, there is also a problem that the detection sensitivity varies for each displacement sensor 90.

Further, the bridge output voltage can be increased by increasing the input voltage applied to the bridge circuit. However, if the gauge resistance is small, the strain gauges 94a to 94d are used.
Generates heat and causes temperature drift, which causes a problem of change in detection sensitivity. In order to prevent this, the gauge resistance (the metal foil 96 of each of the strain gauges 94a to 94d) is
However, if the metal foil 96 having a predetermined pattern is made thin, it becomes difficult to attach it to the resin base 95. There is also a limit to how thin the metal foil 96 itself can be.

The present invention has been made in view of the above circumstances, and an object thereof is to provide a displacement sensor with less temperature drift and deterioration over time, and a method for manufacturing the same. Another object of the present invention is to provide a displacement sensor in which variations in detection sensitivity are suppressed and a manufacturing method thereof. A further object of the present invention is to provide a displacement sensor having a large bridge output voltage and a method for manufacturing the same. Still another object of the present invention is to provide a positioning stage equipped with such a displacement sensor.

[0011]

That is, the first aspect of the present invention
From the viewpoint of, a strain gauge in which an electrode is provided at a predetermined position on one surface of a substantially rectangular insulating substrate, a support member that supports the insulating substrate at both ends in the longitudinal direction thereof, and A head member that is fixed to a central portion and that distorts the insulating substrate when a relative position change occurs between the support member and the support member; and the electrode includes the support member and the head member. When the insulating substrate is distorted due to a change in relative position between the two, two portions where positive strain is generated and negative strain is generated in the insulating substrate.
Displacement sensors are provided, each of which is provided in each part of the place.

In such a displacement sensor, it is preferable to use a pattern in which a ladder pattern and a block pattern are connected as the electrode pattern formed on the strain gauge, and such an electrode pattern is used. Thus, it is possible to easily adjust the resistance value of each electrode (adjustment of gauge resistance). Further, by using a ceramic substrate as the insulating substrate, it is possible to directly form an electrode made of a Cr-N book film having high resistance on the insulating substrate by a PVD method such as a sputtering method.

As described above, since no adhesive is used for the strain gauge, problems of deterioration of the adhesive with time and temperature drift,
The problem of alignment at the time of bonding does not occur, and thereby a highly reliable displacement sensor with less variation in gauge sensitivity and less change in gauge sensitivity over time can be realized. Moreover, since the magnitude of the input voltage can be increased by increasing the gauge resistance, the output voltage can be increased and the gauge sensitivity can be increased. In this case, since the amplification factor of the output voltage can be lowered as compared with the conventional one, S / N
It is possible to raise the ratio. The strain gauge preferably has a gauge factor of 4 or more.

In the strain gauge, connecting conductors for connecting the electrodes provided at four positions in a bridge are formed on the surface of the insulating substrate, and the connecting conductors are electrically connected to the external input / output circuit. It is preferable that the input terminal and the bridge output terminal are provided at positions where the longitudinal direction of the insulating substrate is divided into approximately four equal parts, that is, at portions where stress is not applied most when the insulating substrate is distorted. As a result, it is possible to suppress peeling of the printed circuit board, the lead wire, and the like that are fixed to the bridge input terminal and the bridge output terminal.

According to a second aspect of the present invention, a strain gauge in which an electrode is provided at a predetermined position on a substantially rectangular insulating substrate, a support member for supporting the insulating substrate at both ends in the longitudinal direction thereof, A head member fixed to a substantially central portion of the insulating substrate, wherein the electrode is distorted due to a change in relative position between the supporting member and the head member when the electrode is distorted. A method of manufacturing a displacement sensor provided in each of two portions where positive strain is generated and two portions where negative strain is generated in an insulating substrate, wherein a predetermined pattern is provided at a predetermined position on one surface of the insulating substrate. A method of manufacturing a displacement sensor, comprising: a first step of forming a thin film electrode; and a second step of trimming a pattern of the electrode to adjust its resistance value.

According to a third aspect of the present invention, a strain gauge in which an electrode is provided at a predetermined position of a substantially rectangular insulating substrate, a support member for supporting the insulating substrate at both ends in the longitudinal direction thereof, A head member fixed to a substantially central portion of the insulating substrate, wherein the electrode is distorted due to a change in relative position between the supporting member and the head member when the electrode is distorted. A method of manufacturing a displacement sensor, wherein a thin film having a predetermined pattern is provided at a predetermined position on one surface of an insulating substrate. A bridge-shaped electrode and a connecting conductor for bridge-connecting the electrodes, and a bridge output terminal and a bridge input terminal that conduct with the connecting conductor and conduct with an external input / output circuit. A first step of forming a second for securing said supporting member and said head member to said strain gauge
A displacement sensor manufacturing method comprising: a step of trimming a pattern of the electrode so that an output voltage from the bridge output terminal becomes substantially zero.

By using such a method of manufacturing a displacement sensor, it is possible to easily adjust the gauge resistance of the strain gauge and reduce variations in sensitivity among the displacement sensors. A ceramic substrate having excellent heat resistance is used as the insulating substrate.

According to a fourth aspect of the present invention, there is provided a stage having a predetermined shape, stage moving means for moving the stage in a predetermined direction, and a displacement sensor for measuring the position of the stage. The sensor includes a strain gauge in which electrodes are provided at predetermined positions on a substantially rectangular insulating substrate, support members for supporting the insulating substrate at both ends in the longitudinal direction, and a head fixed to a substantially central portion of the insulating substrate. A member, one of the support member and the head member is fixed to the stage, and the electrode is positive in the insulating substrate when the insulating substrate is distorted due to the movement of the stage. There is provided a positioning stage, which is provided at each of two portions where distortion occurs and two portions where negative distortion occurs, respectively.

Since this positioning stage is provided with the displacement sensor which is excellent in measurement accuracy and has little change in measurement sensitivity with time, accurate positioning can be performed.

[0020]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below with reference to the drawings. 1A is a schematic perspective view of the displacement sensor 1, and FIG. 1B is a schematic perspective view showing a state in which the displacement sensor 1 is wired. The displacement sensor 1 includes a strain gauge 10 in which electrodes 14a to 14d are provided on four sides of a rectangular insulating substrate 11 and a support member that supports the insulating substrate 11 at both ends in the longitudinal direction (X direction). 12 and a head member 13 fixed to a substantially central portion of the insulating substrate 11.

As the insulating substrate 11, a ceramic substrate such as a zirconia thin plate having excellent heat resistance and insulating properties is preferably used. As will be described later, the resistance (gauge resistance) of the electrodes 14a to 14d is preferably adjusted by laser trimming. For this reason, when a resin substrate such as polyimide used in a conventional strain gauge is used as the insulating substrate 11, the resin substrate is burned by the heat of the laser when the electrodes 14a to 14d are trimmed by the laser. There is a risk. When a metal plate having an insulating film formed on the surface is used as the insulating substrate 11, the insulating film is damaged by the heat of the laser when the electrodes 14a to 14d are trimmed by the laser, and the insulating resistance is reduced. However, the bridge output voltage may become unstable due to the leakage current. Therefore, when laser trimming is performed, a ceramic substrate is preferably used as the insulating substrate 11. It should be noted that the insulating substrate 11 is thin enough to have appropriate flexibility.

The support member 12 is made of a highly rigid material such as metal such as stainless steel or cemented carbide or engineering ceramics such as zirconia and silicon nitride. The support member 12 is provided at two positions provided at the end in the X direction. Both ends of the insulating substrate 11 are firmly fixed to the supporting portion 12a. The shape of the support member 12 is not limited to the shape shown in FIG. 1, and may be any shape as long as it can hold the insulating substrate 11 so that it bridges at both ends.

The head member 13 is the head 1 that receives an external force.
3a, and a connecting member 13b for connecting the head 13a and the insulating substrate 11 to each other. The head 13a and the connecting member 13b may be integrally formed. Further, different materials may be used for the head 13a and the connecting member 13b. The head member 13 is preferably made of a highly rigid material, such as metal or engineering ceramics, so that the head member 13 does not deform itself.

Head 1 with support member 12 fixed
When 3a is moved by a predetermined distance in the Z direction shown by arrow B in FIG. 1B, the insulating substrate 11 is distorted. FIG. 2 is an explanatory view showing one form of strain that occurs in the insulating substrate 11 at this time. Negative strain occurs in the central portion of the insulating substrate 11 and positive strain occurs in the end portions. Electrodes 14a-14
Since a large output can be obtained by providing d in the portion where the strain is greatest, the electrodes 14a to 14d
Is close to the X-direction end where positive distortion occurs in the insulating substrate 11 when the insulating substrate 11 is distorted due to a change in the relative position between the supporting member 12 and the head 13a.
It is provided at two locations, a location and a central portion where negative strain occurs.

The electrodes 14a to 14d are made of, for example, a Cr-N book film having a predetermined pattern. Such an alloy thin film can be simultaneously formed directly on the surface of the insulating substrate 11 by using a sputtering method which is one of PVD methods.
Since the electrodes 14a to 14d have a high gauge resistance due to such thinning, even if the bridge input voltage is increased, the magnitude of the current flowing through the gauge resistance can be reduced. This suppresses the generation of Joule heat and suppresses temperature drift. Also, a large output voltage can be obtained. That is, it is possible to increase the gauge sensitivity. In this case, since the amplification factor of the output voltage can be lowered as compared with the conventional case, the S / N ratio can be increased. In addition, the insulating substrate 1 after the Cr-N book film is formed
No. 1 is annealed at about 300 ° C. to 400 ° C. in order to make the temperature coefficient of the Cr-N thin film almost zero.

In the displacement sensor 1, electrodes 14a-1 are provided.
In order to use the strain gauge 10 in which 4d is directly formed on one surface of the insulating substrate 11 at the same time, a strain gauge formed by bonding a metal foil to a polyimide base (hereinafter referred to as "conventional strain gauge").
Is compared with a displacement sensor (hereinafter referred to as a “conventional displacement sensor”) attached to a strain-generating material with an adhesive, the temperature drift and deterioration over time due to the adhesive layer do not occur, so that the positioning accuracy and The reliability can be improved.

Further, in the conventional displacement sensor, the gauge is caused by the variation in the thickness of the adhesive layer between the metal foil and the polyimide base in the conventional strain gauge and the variation in the thickness of the adhesive layer between the strain generating material and the conventional strain gauge. There was a problem that variations in sensitivity occurred, but strain gauge 1
Since 0 can be manufactured without using an adhesive, such a problem does not occur. Furthermore, in the conventional displacement sensor, although it is necessary to attach the conventional strain gauges to both sides of the strain-flexing material with high positional accuracy, there is a limit to improving the accuracy, so cage sensitivity for each conventional strain gauge is limited. However, since the strain gauge 10 can form the electrodes 14a to 14d on one side at the same time, such a problem does not occur and it is easy to establish mutual conduction between the electrodes 14a to 14d. Is.

An electrode 14a of a Cr-N book film is formed on the insulating substrate 11.
14d to 14d are formed, the pattern is finely modified by trimming with a laser or the like, and the electrodes 14a
The magnitude of the gauge resistance of ~ 14d can be easily adjusted.

The pattern of the electrodes 14a to 14d shown in FIG. 1 is a simple folded pattern, and, of course, the gauge resistance can be adjusted by trimming even with such a pattern, but more preferably, the electrodes 14a to 14d are adjusted. By configuring the pattern with ladder-shaped pattern electrodes and block-shaped pattern electrodes, the gauge resistance can be adjusted more easily and precisely.

FIG. 3 shows another embodiment of the pattern of the electrodes 14a to 14d.
Ladder pattern electrode 21 and block pattern electrode 22
It is a top view which shows the electrode pattern which provided the part which connected in series. In the ladder pattern electrode 21, the path length of the current can be changed stepwise by cutting the electrode film with a laser or the like as necessary. Further, since the amount of resistance change when one electrode of the ladder-shaped pattern electrode 21 is cut can be quantitatively grasped, the gauge resistance can be adjusted relatively easily. As a result, the gauge resistance value of each of the electrodes 14a to 14d can be roughly adjusted.

In the case of a Cr-N composite thin film or the like, the temperature coefficient may shift due to heat generated during trimming. However, in the ladder-shaped pattern electrode 21, a portion where the temperature coefficient changes due to laser cutting is used. Since no current flows, there is an advantage that the temperature coefficient is not affected by trimming.

In the block-shaped pattern electrode 22,
The width can be continuously changed by making a cut with a laser or the like. Thus, the electrodes 14a-1
The gauge resistance value can be finely adjusted for each of 4d. By using such a ladder-shaped pattern electrode 21 and a block-shaped pattern electrode 22 together, the electrode 1
The variation in gauge resistance of 4a to 14d can be suppressed to 0.3% or less, and bridge balance can be easily achieved.

For example, the folded pattern electrode 20 is folded back a predetermined number of times with a line width of 20 μm and a thickness of 1 μm, a ladder pattern electrode 21 and a block pattern electrode 22 are provided in the folded pattern electrode 20, and these are trimmed. The electrodes 14a to 14d having a gauge resistance of 5 kΩ and a gauge rate of 6 can be formed. Such trimming of the electrodes 14a to 14d is preferably performed after the insulating substrate 11 is fixed to the supporting member 12 and the head member 13 is fixed to the insulating substrate 11, whereby the displacement sensor 1 is not driven. The bridge balance of the strain gauge 10 in the state can be taken.

FIG. 4 is an explanatory diagram showing an example of the connection form of the electrodes 14a to 14d. The electrodes 14a to 14d accumulate the strains obtained in the respective electrodes 14a to 14d,
It is bridged so that high gauge sensitivity can be obtained.

In order to bridge-connect the electrodes 14a to 14d as shown in FIG. 4, the insulating substrate 11 is provided with connecting conductors 14e at a plurality of locations (see FIGS. 1A and 3). In addition, each connection conductor 14e has a bridge input terminal 15 that conducts with an external input / output circuit.
b · 15d and bridge output terminal 15a · 1
5c is formed. Bridge input terminal 15
b · 15d and bridge output terminal 15a · 1
As shown in FIG. 2, 5c is provided at a position that divides the longitudinal direction of the insulating substrate 11 into approximately four equal parts, that is, at a position where strain does not easily occur when the insulating substrate 11 is strained.

As shown in FIG. 1B, the terminal 17
a to 17d and 18a to 18d, and terminals 17a to 1
7d and terminals 18a to 18d are connected to the printed wiring board 16 provided with lead wires 19a to 19d in a one-to-one relationship. The bridge output terminal 15a is electrically connected to the terminal 17a, and the bridge input terminal 1
5b is electrically connected to the terminal 17b, the bridge output terminal 15c is electrically connected to the terminal 17c, and the bridge input terminal 15d is electrically connected to the terminal 17d.

The printed wiring board 16 is an insulating film having a high flexibility, for example, a thickness of 25.
A polyimide film of about μm is preferably used. In addition, as shown in FIG.
By providing the character-shaped buffer 26, it is possible to suppress the displacement inhibition of the insulating substrate 11 by the printed wiring board 16.

Bridge input terminals 15b and 15d
By disposing the bridge output terminals 15a and 15c at positions on the insulating substrate 11 where distortion is unlikely to occur, peeling of the printed wiring board 16 can be prevented, and the distortion that occurs in the insulating substrate 11 due to soldering is hindered. It will be difficult.

Cables 25a to 25d for connecting to the input / output devices are attached to the terminals 18a to 18d. Of course, the cables 25a to 25d may be directly connected to the bridge output terminals 15a and 15c and the bridge input terminals 15b and 15d, respectively, without using the printed wiring board 16. In addition, the cables 25a to 25d are fixed at predetermined positions, and the ends of the cables 25a to 25d and the bridge output terminals 15a and 15c and the bridge input terminals 15b and 15d are electrically connected by wire bonding. Good.

In the conventional strain gauge, the gauge resistance is 10
Since it was only about 0Ω, the voltage applied between the bridge input terminals 15b and 15d (bridge input voltage) could only be raised to about 2V. However, as described above, in the strain gauge 10, the electrodes 14a ...
Since it is possible to increase the gauge resistance of 14d to 5 kΩ, the bridge input voltage can be increased to 10 V, which is about five times higher than the conventional value. Further, the gauge ratio of the conventional strain gauge is 2, but the strain gauge 10 has a triple rate of 6
Has a gauge ratio of. For this purpose, the strain gauge 10
In the case of using, the bridge output voltage (the output voltage taken out from the bridge input terminals 15a and 15c) can be obtained about 15 times as compared with the case of using the conventional strain gauge.

By obtaining such a large output, the amplification factor of the amplifier for amplifying the bridge output voltage can be lowered and the S / N ratio can be improved. FIG. 5 is an explanatory diagram showing the relationship between the bridge output voltage in the displacement sensor 1 and the displacement amount of the head 13a when the amplification factor of the amplifier is set to 1/10 of the conventional one.
It can be seen that a positive linear correlation is obtained with the displacement amount of a. The reason why the bridge output voltage is higher than that of FIG. 8 shown as the conventional example is that the bridge input voltage is changed from 2V to 10V and the gauge factor is changed from 2 to 6.

Next, the positioning stage equipped with the displacement sensor 1 will be described. FIG. 6 shows the positioning stage 30.
FIG. 7 is a plan view showing the schematic structure of FIG. 7, and FIG. 7 is an explanatory view showing an embodiment of a drive system for the positioning stage 30. The positioning stage 30 includes a movable part (stage part) 3
1 and a fixed portion 32, which are connected by parallel springs 33 provided at four locations. The laminated piezoelectric actuator 34 is provided in the recess 45 provided in the movable portion 31.
Are fixed so as to straddle the movable portion 31 and the fixed portion 32. The piezoelectric actuator 34 is driven by a driver 35 and expands and contracts in the Y direction when a predetermined voltage is applied.

In the displacement sensor 1, the support member 12 is fixed to the concave portion 46a (formed so as to be recessed in the direction perpendicular to the paper surface in FIG. 6) provided in the movable portion 31 by the screw 41a, and is provided in the fixed portion 32. The head 13a is fixed by a screw 41b to the recessed portion 46b (formed like the recessed portion 46a so as to be recessed in the direction perpendicular to the paper surface in FIG. 6) and mounted on the positioning stage 30.

An example of the driving mode of the positioning stage 30 will be described below. First, the positioning stage 30
When the piezoelectric actuator 34 is not driven, the electrodes 14a to 14d (FIG. 6) of the strain gauge 10 are adjusted so that the bridge output voltage from the displacement sensor 1 becomes 0V.
Not shown. Adjust the bridge resistance in Fig. 1). Specifically, the displacement sensor 1 is attached to the positioning stage 3
It is incorporated into 0, and thereafter, by applying a predetermined bridge input voltage and measuring the bridge output voltage, the electrodes 14a to 14d are successively trimmed so that the bridge output voltage becomes 0V.

When such bridge balance adjustment is not performed, the processing accuracy of the movable portion 31 and the parallel spring 33,
Depending on the mounting accuracy of the displacement sensor 1 and the like, it is necessary to correct the relationship between the bridge output voltage of the displacement sensor 1 and the displacement amount for each positioning stage 30. However, the positioning stage 30 can avoid such a problem.

When a drive signal for the piezoelectric actuator 34 is sent from the controller 36 to the driver 35, a predetermined voltage is applied from the driver 35 to the piezoelectric actuator 34.
As a result, when the piezoelectric actuator 34 expands and contracts,
The movable portion 31 moves in the Y direction with respect to the fixed portion 32. When the movable part 31 moves, the support member 12 fixed to the movable part 31 moves in the Y direction, so that the strain gauge 10 is distorted at this time. By applying a predetermined bridge input voltage to the strain gauge 10, a bridge output voltage corresponding to the magnitude of this strain can be obtained.

The obtained bridge output voltage is amplified by the strain gauge amplifier 37 at a predetermined amplification factor, and the amount of displacement detected by the displacement sensor 1 in the control unit 36 is obtained from the value of this amplified voltage. The control unit 36 further controls the driver 35 so that the displacement sensor 1 indicates the desired displacement amount.
A drive signal for the piezoelectric actuator 34 is sent to the piezoelectric actuator 34, and the expanded / contracted state of the piezoelectric actuator 34 is maintained in a state in which the displacement sensor 1 indicates the intended displacement amount. In the positioning stage using the displacement sensor 1 having the characteristics shown in FIG. 5, resolution: 5 nm, positioning accuracy: ± 30 nm, reproducibility: ±
5 nm was obtained.

The displacement sensor of the present invention, the manufacturing method thereof, and the positioning stage using the displacement sensor have been described above. In the displacement sensor 1 of the present invention, the relative positions of the support member 12 and the head member 13 are different. Support member 1
2 or the deformation amount of the insulating substrate 11 when the head member 13 is changed by applying a predetermined force to the strain gauge 10.
Needless to say, since the measurement principle of measurement is used, it is not limited to being used as a displacement sensor and can be used as a pressure sensor or a force sensor. Further, the displacement sensor of the present invention is not limited to use as the positioning mechanism of the positioning stage, but can be used as other positioning devices (positioners).

[0049]

As described above, according to the present invention, the electrodes can be simultaneously formed at four positions on one side of the insulating substrate, so that the accuracy of the positions where the electrodes are formed can be improved and the bridge connection of each electrode can be achieved. Is also easy. As a result, it is possible to suppress variations in gauge sensitivity for each displacement sensor,
Further, since the occurrence of temperature drift and deterioration over time can be suppressed, reliability can be improved. Furthermore, since it is easy to thin the electrodes formed on the insulating substrate to increase the gauge resistance, the bridge input voltage can be increased. As a result, a large bridge output voltage is obtained and S / N
Since the ratio can be increased, the gauge sensitivity can be increased. Furthermore, since the gauge resistance can be easily adjusted by trimming or the like, variations in the gauge resistance can be suppressed. When the displacement sensor is incorporated in a device such as a positioning stage and used, the variation in characteristics of each positioning stage can be suppressed by adjusting the bridge balance of the strain gauge after incorporating the displacement sensor in the device.

[Brief description of drawings]

FIG. 1 is a schematic perspective view showing an embodiment of a displacement sensor of the present invention using a strain gauge.

FIG. 2 is an explanatory view showing one form of strain generated in a strain gauge in a displacement sensor.

FIG. 3 is a plan view showing another embodiment of the electrode pattern formed on the strain gauge.

FIG. 4 is an explanatory diagram showing an example of a connection form of electrodes formed on a strain gauge.

FIG. 5 is an explanatory diagram showing a relationship between a bridge output voltage and a displacement amount of a head in a displacement sensor.

FIG. 6 is a schematic plan view of a positioning stage.

FIG. 7 is an explanatory diagram showing an embodiment of a positioning stage drive system.

FIG. 8 is an explanatory diagram showing a relationship between a bridge output voltage and a head displacement amount in a displacement sensor using a conventional strain gauge.

FIG. 9 is a schematic perspective view of a displacement sensor using a conventional strain gauge.

FIG. 10 is an explanatory diagram showing an example of a connection form of strain gauges.

[Explanation of symbols]

1; displacement sensor, 10; strain gauge, 11; insulating substrate,
12; support member, 13; head member, 14a to 14d;
Electrodes, 14e; Connection conductors, 15a and 15c; Bridge output terminals, 15b and 15d; Bridge input terminals, 16; Printed wiring boards, 17a to 17d;
Terminals, 18a-18d; Terminals, 19a-1
9d; lead wire, 20; folded pattern electrode, 21;
Ladder-shaped pattern electrode, 22; block-shaped pattern electrode,
25a to 25d; cable, 26; buffer, 30; positioning stage, 31; movable part, 32; fixed part, 33;
Parallel spring, 34; Piezoelectric actuator, 35; Driver, 36; Control unit, 37; Strain gauge amplifier, 41a
41b; screw, 45, 46a, 46b; recess, 90; displacement sensor, 91; base part, 92; straining material, 93; sensor head, 94a to 94d; strain gauge, 95; resin base, 96; metal foil , 97; correction resistor, 98; input / output terminal

   ─────────────────────────────────────────────────── ─── Continued front page    (71) Applicant 501421373             Atsushi Furuta             3-4-25-303 Fuji, Urayasu City, Chiba Prefecture             Yarheim Yoshibashi (72) Inventor Mutsuo Mukata             2-19-51 Senjodainishi, Wakaba Ward, Chiba City, Chiba Prefecture (72) Inventor Toshiro Higuchi             3-4-26 Edahigashi, Tsuzuki-ku, Yokohama-shi, Kanagawa (72) Inventor Jun Furuta             3-4-25-303 Fuji, Urayasu City, Chiba Prefecture             Yarheim Yoshibashi F term (reference) 2F049 AA12 AA13 AA14 BA13 CA01                       CA07 DA01 DA04                 2F063 AA02 CA08 DA02 DA04 DC08                       DD05 EC03 EC13 EC14 EC20                       EC21 EC25 EC26 LA11 LA27                 2F077 AA41 AA42 EE07 TT16 UU15                       VV02 VV11 VV31 VV33                 2F078 CA08 CB02 CB09 CB14 CC14                       CC19

Claims (8)

[Claims] 1. A strain gauge in which an electrode is provided at a predetermined position on one surface of a substantially rectangular insulating substrate, a support member for supporting the insulating substrate at both ends in the longitudinal direction thereof, and a substantially central portion of the insulating substrate. A head member that is fixed to a portion and that distorts the insulating substrate when a relative position change occurs between the support member and the support member; and the electrode includes the support member and the head member. When the insulating substrate is distorted due to a change in relative position between the two, the insulating substrate is provided with two portions where positive strain is generated and two portions where negative strain is generated, respectively. Displacement sensor characterized in that. 2. The displacement sensor according to claim 1, wherein the electrode has a pattern in which a ladder pattern and a block pattern are connected. 3. The displacement sensor according to claim 1, wherein the insulating substrate is a ceramic substrate. 4. The electrode is a Cr-N book film directly formed on the insulating substrate by a PVD method, and has a gauge factor of 4 or more. The displacement sensor according to any one of 1. 5. A bridge input terminal for forming a connection conductor for bridge-connecting the electrodes on the insulating substrate, and for conducting a conduction with the connection conductor and an external input / output circuit, The displacement sensor according to any one of claims 1 to 4, wherein the bridge output terminal is provided at a position that divides the longitudinal direction of the insulating substrate into approximately four equal parts. 6. A strain gauge in which an electrode is provided at a predetermined position of a substantially rectangular insulating substrate, a support member for supporting the insulating substrate at both ends in the longitudinal direction, and a strain gauge fixed to a substantially central portion of the insulating substrate. A head member, wherein a positive strain is generated in the insulating substrate when the electrode is strained due to a change in a relative position between the supporting member and the head member. A method of manufacturing a displacement sensor provided in each of a portion and a portion in which a negative strain occurs, wherein a thin film electrode having a predetermined pattern is formed at a predetermined position on one surface of an insulating substrate. A method of manufacturing a displacement sensor, comprising: a step of trimming a pattern of the electrode to adjust a resistance value thereof. 7. A strain gauge in which electrodes are provided at predetermined positions on a substantially rectangular insulating substrate, support members for supporting the insulating substrate at both ends in the longitudinal direction thereof, and fixed to a substantially central portion of the insulating substrate. A head member, wherein a positive strain is generated in the insulating substrate when the electrode is strained due to a change in a relative position between the supporting member and the head member. A method of manufacturing a displacement sensor provided in a portion of a location and in a location of two locations where negative strain occurs, which is a thin film electrode having a predetermined pattern at a predetermined position on one surface of an insulating substrate and the electrode is bridge-connected. And a first step of forming a bridge output terminal and a bridge input terminal that are electrically connected to the connection conductor and are electrically connected to an external input / output circuit, and the distortion. Third to trim a second step of securing said supporting member and said head member in the gauge, the pattern of the electrodes so that the output voltage from the bridge output terminals becomes substantially zero
A method of manufacturing a displacement sensor, comprising: 8. A stage having a predetermined shape, stage moving means for moving the stage in a predetermined direction, and a displacement sensor for measuring the position of the stage, wherein the displacement sensor is a substantially rectangular insulating substrate. A strain gauge having an electrode provided at a predetermined position; a supporting member that supports the insulating substrate at both ends in the longitudinal direction thereof; and a head member fixed to a substantially central portion of the insulating substrate. One of the member or the head member is fixed to the stage, and the electrode has two portions where a positive distortion is generated in the insulating substrate when the insulating substrate is distorted due to the movement of the stage and a negative portion. The positioning stage is provided at each of two locations where the distortion occurs.