JPH04366702A - Minute displacement detector - Google Patents

Abstract

PURPOSE:To obtain a minute displacement detector which can detect a minute displacement with high accuracy in a compact and simple structure, and can be used in a superhigh vacuum ambiance or a very low temperature ambiance. CONSTITUTION:A resistance line 2 is formed on the surface 5 of a cantilever 1 whose one end is made at a fixed end 3 and the other end is made at a free end 4. Follwing the displacement of y of the fixed end 4 by a force F applied to the free end 4 of the cantilever 1, the resistance value of the above resistance line 2 is changed by a piezo-resistance effect, by a stress applied to the resistance line 2.

Description

[Detailed description of the invention]

0001

[Industrial Application Field] The present invention is capable of detecting minute displacements with high sensitivity.
This invention relates to a minute displacement detector for highly accurate detection.

0002

[Prior Art] Recently, with the advent of atomic force microscopes, minute displacements (for example, 0.1
It has become necessary to detect nanoparticles (nm order) with high sensitivity. Of course, detecting such minute displacements requires
The atomic force (generally 10-
(on the order of 7 to 10-9 N or less), and at present, as specific methods for this purpose, the following two devices or methods have been proposed.

One method is to combine a tunneling electron microscope as shown in FIG. First, referring to Figure (A), to explain the device structure, there is a cantilever 31 with one end serving as a fixed end 33 and the other end serving as a free end 34, and near the upper surface of the free end of the cantilever 31. , a probe 42 provided at the tip of a piezo element 41 faces. When the distance δ between the probe 42 and the upper surface of the cantilever free end 34 is set to about 1 nm or less and an appropriate bias voltage V is applied between them, a tunnel current it starts to flow through the vacuum barrier. . Therefore, in order to keep the amount of tunnel current constant, a piezo voltage E is applied between a pair of electrodes 43, 43 provided at both ends of the piezo element 41.
is controlled to expand and contract the piezo element 41. According to such a method, as shown in FIG. 9(B), when the free end 34 is displaced by Δy due to atomic force or the like, by controlling the piezo voltage E to keep the tunnel current it constant, As a result, the length of the piezo element 41 is also Δy
only changes. Therefore, conversely, the physical or dimensional displacement Δy can be detected by converting it into a change in electrical quantity, and in fact, the maximum sensitivity of displacement detection using this method is equal to that of an ordinary tunneling electron microscope. Same as 0.0
A good value of about 1 nm can be obtained.

Another conventional method for detecting minute displacements uses a so-called "optical lever" as shown in FIG. This method geometrically amplifies and detects the amount of physical displacement of a certain point as a movement of a light point, and the device configuration is shown in FIG. 3(A). It is similar to the previous example in that it uses a cantilever 31 with one end being a fixed end 33 and the other end being a free end 34, but it is desirable that a separate light source has good directivity, so generally is a laser light source 50 and its light receiving section 51
Requires. Here, if the laser beam from the laser light source 50 irradiates the vicinity of the upper surface of the cantilever free end 34 at an incident angle θ when the cantilever 31 is not displaced, the surface at the irradiated position near the cantilever free end 34 If the smoothness of the light receiving section 51 is maintained sufficiently high, the reflected light will naturally go out in the direction of the output angle θ, which is the same angle as the incident angle. Initialize the measurement system. After initial settings,
As shown in the same figure (B), if the cantilever 31 makes a minute displacement Δy with the fixed end 33 as a fulcrum, the incident angle of the irradiation light from the laser light source 50 will also change slightly from θ and become ψ. , an angular change of 2(ψ-θ) occurs in the specularly reflected light, and accordingly, a light receiving position change of Δx occurs in the light receiving section 51. The amount of change in Δx with respect to the actual displacement Δy is geometrically amplified as the distance (light receiving distance) L between the reflection position near the free end of the cantilever and the light receiving position of the light receiving section 51 is longer. Become. For example, if the length l of the cantilever 31 is 1 mm, the maximum sensitivity is 0.
Considering detecting minute displacement Δy up to 1 nm,
The change in the reflection angle of the laser beam is estimated to be 1.1 x 10-5 degrees, so if the light receiving distance L is 1 m, the change in the light receiving position Δx
is about 10-2 mm, which is within the range that can be detected with sufficiently high resolution even with existing light spot position detection systems.

[0005]

[Problems to be Solved by the Invention] As mentioned above, whether it is the conventional method using a combination with a tunneling electron microscope or the conventional method using an optical lever, the sensitivity itself regarding the detection of minute displacements of the free end of the cantilever tip is It can be said that a satisfactory value has been obtained. However, when considering whether or not they are practical devices, each of them has the following drawbacks.

[0006] In the method using a tunneling electron microscope,
It is necessary to bring the probe close to the position where the tunneling current can be detected, but the equipment for this is complex and requires high precision, and the equipment as a whole becomes large.
It is also vulnerable to vibration. Removal of vibration is one of the essential and most important measurement environment conditions for this type of minute displacement detection in principle. Furthermore, in this method, the distance between the cantilever and the probe must be controlled so that the tunneling current remains constant each time a measurement is made, so that no improvement in work efficiency can be expected and the operability is extremely poor.

On the other hand, the biggest problem with the method using an optical lever is that the entire device becomes extremely large, even more than the method using a tunneling electron microscope. As explained with reference to FIG. 10, in order to detect minute displacements using this method, the separation distance between the cantilever and the light receiver must be quite large. Sensitivity is 0.1 nm, an order of magnitude lower than that using a tunneling electron microscope.
Even if the degree is satisfactory, the separation distance or light receiving distance L between the cantilever and the light receiver that is necessary for that purpose is
In practice, the distance can be as long as 1 m as mentioned above. If an attempt is made to further increase the amount of geometrical amplification of minute displacements and further improve the detection resolution, a longer light receiving distance will be required, as a matter of course based on the principle of this method. As it turns out, it is almost impossible to isolate vibrations from the entirety of such an extremely large equipment system. Furthermore, in the method using this optical lever, scattering or diffused reflection on the surface of the cantilever that is irradiated with the laser beam cannot be ignored. In order to achieve a mirror finish on the surface of the cantilever to a level that is satisfactory for measurements, extremely high processing precision is required, even with the use of existing polishing techniques, which are quite advanced.

Furthermore, all of these conventional methods have the drawback that it is difficult to isolate vibrations from the entire device system, and it is also difficult to use them in combination with ultra-high vacuum devices or cryogenic devices. In the future, observation of minute displacements based on microfabrication performed in ultra-high vacuum environments (especially in semiconductor processes) and various phenomena in cryogenic environments will increasingly be required from various technical fields. There is no doubt that the government will come, but not being able to respond to this will be a huge loss. In view of the above-mentioned circumstances, it is an object of the present invention to provide a simple and highly accurate minute displacement detector that can eliminate all the drawbacks of the above-mentioned conventional example, based on a new principle.

[0009]

[Means for Solving the Problems] In order to achieve the above object, the present invention has a cantilever that has a length between a fixed end and a free end and can be slightly displaced using the fixed end as a fulcrum. Although similar to the example, we will first propose a minute displacement detector in which the cantilever is made insulative and is provided with a resistance line whose resistance value changes due to the piezoresistance effect. However, insulating properties in this book include semi-insulating properties, and also include the electrical state of materials that are semiconductors that are intrinsic or nearly intrinsic semiconductors and have extremely high specific resistance. In other words, it refers to a material that is selected to form a resistance line and whose piezoresistance effect is not recognized or can be almost ignored compared to a resistive material that can exhibit a piezoresistance effect. The resistance line may be created separately from the cantilever and attached to the cantilever later, or may be formed by printing or vapor deposition, or as described above, even if the cantilever is insulating, it may be an intrinsic or nearly intrinsic semiconductor. When the line is made of a material, it can be formed as a semiconductor line having a so-called specific conductivity type by doping the semiconductor material with an appropriate impurity. Furthermore, if the cantilever itself is resistive instead of being insulative, the resistance line provided therein may be the cantilever itself. Also, according to another aspect of the present invention,
A minute displacement detector is also provided in which the cantilever is provided with an insulating material line whose electromotive force changes due to the piezoelectric effect in response to stress accompanying minute displacement of the cantilever, in place of the above-mentioned resistance line. In this case as well, if the cantilever itself is made of an insulating material whose electromotive force changes due to piezoelectric effect in response to the stress caused by its minute displacement, the cantilever itself should be used as an insulating material line provided on the cantilever. Can be done.

0010

DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1A shows the main parts of a basic embodiment of a minute displacement detector constructed according to the present invention. First, one end is a fixed end 3 that is stably and firmly supported by a suitable support member 9, and the other end is a cantilever (cantilever beam) 1 that is a free end 4 that can be displaced.
In the case shown, this cantilever 1 has a length l,
It has a rectangular parallelepiped rod shape with a width b and a thickness h. However, since the thickness h is actually made extremely thin, a rectangular plate shape is more appropriate. However,
A resistance line 2 is provided on one surface (for example, if the surface shown in the figure is the surface) of both the front and back main surfaces of this cantilever 1 defined by length l and width b. . In the illustrated embodiment, the resistance line 2 is the cantilever 1
A pair of mutually parallel strip-like pattern parts 21, 21 extending between the fixed end side and the free end side of (are the ends of the free end of the cantilever)
and a folded pattern portion 22 that electrically connects. As a result, the resistance line 2 has a hairpin shape as a whole in this case, and is located on the fixed end side of the cantilever 1 between the pair of open ends of the hairpin.
That is, in the illustrated embodiment, a required electrical resistance value can be obtained between the ends to which the electrodes 8, 8 are respectively attached. As long as this resistance line 2 literally has electrical resistance in the usual sense, it is expected to have a piezoresistance effect. Rather, the line 2 is formed of a material or substance exhibiting a rate of change that can cause a resistance value change within a detectable range by a minute displacement detection mechanism described below.
In the present invention, this is referred to as the resistance line 2, and the piezoresistance effect is not recognized, or even if it is, it is negligible compared to that of the resistance line 2.The electrical property of the material or substance is insulated. It's called sex. Therefore, the insulating material can include a so-called semi-insulating material, a semiconductor that is an intrinsic semiconductor, or a semiconductor that is close to it.

A specific method for forming the resistance line 2 on one surface of the cantilever 1 will be described later.
In the micro-displacement detector of the present invention having the configuration shown in FIG. 1(A), the cantilever 1, which had previously been flat, is now When some force F is applied to the free end 4 of the cantilever 1, for example from bottom to top, a compressive stress is applied to the front surface 5 of the cantilever 1, and a tensile stress is applied to the back surface 6 of the cantilever 1. This stress changes the resistance value between both ends of the resistance line 2 formed on the surface 5 of the cantilever 1 in this embodiment. therefore,
If the electrodes 8, 8 provided at both ends of the resistance line 2 are led to an appropriate measurement system (not shown) via an appropriate electrical signal line and this minute change in resistance is detected, the applied force can be measured. The minute displacement Δy generated at the free end 4 of the cantilever 1 by F can be converted into an electrical quantity and detected, and thus the magnitude of the applied force F can be known. Of course, the direction of the displacement Δy or the direction of the force F can also be detected. Unlike the above, if the applied force F is from above to below, the stress applied to the resistance line 2 also changes from compressive stress to tensile stress, so the direction of change in resistance value also changes. be.

In order to demonstrate the practicality of the minute displacement detector of the present invention based on such a principle, a concrete fabrication example will be discussed. For example, if the insulating cantilever 1 is an intrinsic or almost intrinsic semiconductor, by using an existing semiconductor processing process and introducing impurities onto its surface according to a predetermined pattern, the structure shown in FIG. 1(A) can be obtained. It is possible to relatively easily make a planar resistance line 2 that has a shape similar to that shown in FIG. If the structural semiconductor of the cantilever 1 is silicon, the resistance line 2 can be formed as an n-type semiconductor line by introducing arsenic. In fact, the length l is 20
For the surface 5 of an intrinsic silicon cantilever 1 having a width b of 0 μm, a width b of 20 μm, and a thickness h of 2 μm, the doping amount of arsenic is 1019/cm, and each length is about 200 μm, which is almost the same as the length of the cantilever. , strip pattern portions 21 and 2 each having a line width of 5 μm and a depth of 1 μm.
1 (therefore, if the length of the folded pattern portion 22 is ignored, the total length of the resistance line 2 is approximately 400 μm), the Young's modulus of the silicon is 11.26×10 N/m2 (source :AIP
Handbook 3rd ed. ．． McGRAW-
HILL), so if the free end 4 of the cantilever is displaced, for example, by 0.18 nm, the compressive strain in the lateral direction received by the surface of the cantilever where the resistance line 2 is provided will be about -10-8. On the other hand, the sensitivity to distortion is [1
00] direction -133 (Source 1: C.S. Smith,
Phys. Rev. 94, (1954) 42;
Source 2: “Research report on basic sensor technology 1
", Japan Electronic Industry Promotion Association, 1985), the resistance change rate of resistance line 2 at that time is 10-6.
It will be about. Therefore, the resistance value of the resistance line 2 measured under steady state is 1KΩ when created under the above conditions.
Therefore, the change in resistance value due to the compressive strain described above is approximately 1 mΩ, which is within the range that can be sufficiently detected using the existing electrical measurement system. In other words, the minute displacement detector of the present invention has sufficient detection ability for minute displacements on the order of subnanometers. Note that the resonant frequency of the cantilever 1 under the above conditions can be calculated to be approximately 36 KHz.

[0013]Although the detection sensitivity of minute displacements varies depending on the geometric size and material of the cantilever 1, generally speaking, the length of the cantilever 1 should be made as long as possible, the width should be made as short as possible, The thinner the thickness, the better the sensitivity. Of course, the sensitivity can be improved or adjusted depending on the impurity used to form the resistance line 2 and also on the conductivity of the resistance line 2.

Of course, the fact that a minute displacement can be detected in the above also means that the magnitude of the force F that caused the minute displacement can be measured. For example, in the case of the above specific example, the spring constant is 0.56 N/m, so as mentioned above, if the minute displacement Δy is detected as 0.18 nm, the force F applied at this time will be The size is 1
It turns out that it is 0-10N. Therefore, the minute displacement detector of the present invention can have the ability to detect a minute force F of this order.

[0015] Note that the part or displacement Δy where the force F is detected
The region where this occurs is not the free end 4 of the cantilever 1,
If it is known that the force F or the displacement Δ is limited to a portion midway in the length direction from the fixed end 3 to the free end 4, the force F or displacement Δ can be reduced by folding back the resistance line 2 near that point.
y can be detected, and sensitivity can thereby be increased. For example, if the fixed end side and the free end side are likely to warp in opposite directions with respect to the region where the force F or displacement Δy occurs, the cantilever 1 can be warped over almost the entire length in the longitudinal direction. If there is a resistive line that extends, the change in resistance is canceled out and the effective sensitivity decreases, but if the line is formed only up to the displacement point, there is no risk of this happening.

The minute displacement detector of the present invention can also detect acceleration. For example, suppose that a sudden acceleration is applied to the detection system shown in FIG. 1 due to an earthquake or the like. Here, the vibration frequency that causes acceleration is the resonant frequency of this measurement system (in the case of the specific example mentioned above, 3
6KHz), and the resistance force against acceleration is proportional to the speed, and this proportionality coefficient itself is sufficiently large compared to the period of acceleration, then in this case, as shown in Figure 2.
As shown in , the center of gravity G of the cantilever 1 is stationary in space. Then, about this center of gravity G, the free end 4 side of the cantilever 1 is displaced by Δy1, and the fixed end 3 side is displaced by Δy2. With these two displacements,
The resistance value of the resistance line 2 will change, but since the relationship between the displacement Δy1 on the free end side and the displacement Δy2 on the fixed end side is predictable, the actual displacement Δy due to the sudden acceleration α
y2 can also be detected by conversion. Furthermore, if the resistance line 2 is folded back at the center of gravity G, it will not be affected by the displacement Δy1 on the free end side, according to the theory stated earlier.
It is possible to detect only the displacement Δy2 due to acceleration, and thus only the acceleration.

[0017] In the following, various modifications to the basic embodiment of the minute displacement detector of the present invention described above, such as structural modifications and modifications to the shape of the resistance line pattern, will be explained. In the embodiment of the present invention shown in FIG. 1, the resistance line 2 formed on the surface 5 of the cantilever 1 had a hairpin shape, but as shown in FIG. It is also possible to do this. That is, in the case of the embodiment shown in FIG. 3, there are a total of six mutually parallel strip pattern portions 21 extending between the fixed end 3 and the free end 4 of the cantilever 1; In order, adjacent ones are electrically connected alternately at the fixed end side and the free end side by the folded pattern portions 22, . . . . In this way,
Naturally, a pair of both end electrodes 8, 8 of the resistance line 2
Not only does the resistance value between the two electrodes become higher, but also the change in resistance value due to stress associated with minute displacement becomes larger, resulting in improved sensitivity. In this case, the number of meanderings can be determined arbitrarily. In other words, if there are a total of n mutually parallel strip-like pattern parts 21, etc., where n is generally a number of 3 or more, these are alternately connected at opposite ends, and the whole is meandering. When forming the shaped resistance line 2, the number of required folded pattern parts is n-1, but there is no restriction in principle on the value of n. It may be within a range that can be fabricated on one surface of the same cantilever as an actual product.

Naturally, the larger the value of n mentioned above, the better the sensitivity for detecting minute displacements will be. However, considering the above in reverse, if there is no sensitivity problem, the minute displacements of the present invention The most basic resistance line shape for a detector is shown in Figure 1 (
A) It is even simpler than the hairpin shape shown in FIG.
It is also understood that the shape may be made of only. In this case, in FIGS. 1A and 3, the electrodes 8 and 8 provided at both ends of the resistance line 2 are both formed on the fixed end side of the cantilever 1, particularly on the surface of the support member 9, Instead, one of them will be formed on the free end side. However, there is no problem even if this is the case. It is possible to wire the electrode provided on the free end side of the cantilever to the measurement system easily using existing fine wiring technology. It is also possible to provide probe-like electrodes in close proximity and establish an electrical connection to the resistance line through the presence of tunneling current. Therefore, even if the pair of electrodes 8, 8 are both aligned on one end side in the length direction of the cantilever 1, nothing is aligned on the fixed end 3 side of the cantilever 1, as in the previously described embodiment. It is not necessary that they be aligned, and if necessary, they may be aligned on the free end 4 side. For example, Figure 1 (
This means that the hairpin shape shown in A) and the meandering shape shown in FIG. 3 may be oriented in the opposite direction to the direction shown in the figure. Furthermore, if the above is considered comprehensively, even if the meandering shape shown in FIG. This means that even if the electrode 8 has to be formed at least on the free end side of the cantilever, there is no problem. First, the electrodes 8, 8 themselves are for explanatory purposes only, and it goes without saying that they may actually be formed, for example, in a dot-like pattern; Additionally, communication between both ends of the resistance line to the measurement system may be established via a continuous line pattern portion (not shown) formed on the support member 9.

[0019] Regarding the part mentioned above as a strip-like pattern part, it roughly means that it only needs to extend in the length direction, and it is only applicable to narrow and straight line patterns. It is not limited. It may be undulating in the middle, or it may have thick parts and thin parts alternating. In particular, when the displacement part can be predicted and you want to set the degree of change in resistance value with respect to displacement as the entire length of the resistance line to a desired value by setting an appropriate reference resistance value for that part, use this method. It is also effective to change the geometrical and partial pattern shape (the same objective can also be achieved by locally changing the doping amount in the case of introducing impurities as described above). Of course, the folded pattern part 2
The same applies to line 2, and any suitable line pattern shape may be used.

Furthermore, a plurality of resistance lines 2 may be provided to the cantilever 1. For example, as shown in FIG. 4, two hairpin-shaped resistance lines 2, 2 may be arranged in parallel on the surface 5 of the cantilever 1. In this case as well, the number of parallel lines is arbitrary, and the overall shape of the individual resistance lines 2, 2 is also arbitrary, and they do not necessarily have to be the same shape. The number of meandering lines may be different, or at least one resistance line 2 may be formed of a simple strip pattern. Each of the independent resistance lines can be used electrically independently, and can also be used depending on the use or purpose by external wiring.
They may be used by being connected in series or in parallel. It is common to think that the series connection is to improve sensitivity, and the parallel connection is to increase the current capacity of the resistance line 2.
This does not preclude other special applications. In some cases, in order to remove noise components superimposed on the displacement, such series or parallel connections may be effective by modifying the overall pattern and direction of each resistance line 2.

Even if a plurality of resistance lines are provided for one cantilever 1, the cantilever 1 shown in FIG.
As shown in a perspective view of the cantilever 1 as seen from the front surface 5 side, and as shown in FIG.
may be provided and used independently. Figure 5 is Figure 1
This is an embodiment in which one resistance line with a hairpin pattern similar to that shown in (A) is formed on each of the front and back surfaces of the cantilever 1. The number of resistance lines 2 formed on each side and the overall shape of each are arbitrary. Furthermore, in principle, these plurality of resistance lines may be used independently, or may be used in series or parallel connection with each other depending on the purpose, as described above. However, when connecting resistance lines that are formed in the same two-dimensional plane pattern and distributed on the front and back surfaces of the cantilever, the resistance value changes in the opposite direction with respect to the displacement, and the absolute value is the same. In some cases, they cancel each other out. Naturally, I can't imagine using it in such a way.

In principle, there are no major restrictions on the two-dimensional or three-dimensional shape of the cantilever 1. For example, Figure 6
As shown in the figure, the shape may be a wedge shape in which the thickness becomes thinner as it goes from the fixed end side to the free end side, or it may have a tapered shape in which the width becomes narrower toward the tip (not shown). Besides, if there is a concept of a fixed end and a free end, almost any planar shape or cross-sectional shape can be accepted (
However, as mentioned above, the thinner, thinner, and longer the shape, the better the sensitivity for detecting minute displacements. Further, as shown in FIG. 7, the planar outline of the cantilever 1 is triangular, but it may be shaped like a hollow frame. In such a case, it can be seen that there are essentially two fixed ends 3.

It can be inferred from this that the number of fixed ends may be any number. For example, if we consider a cantilever that has a fixed end at two perpendicular points in a plane and a free end at an appropriate distance from the two fixed ends, such a cantilever has fixed ends at two orthogonal points in the plane, and free ends at appropriate distances from the two fixed ends. Since displacement is possible, by using at least two resistance lines 2 and arranging them so that they are perpendicular to each other, it is possible to detect minute displacements in two directions within the plane by monitoring the change in the resistance value of each. As a result, it becomes possible to detect minute displacements in all directions. Of course, as shown in FIG. 8, for example, a chip-shaped protrusion 10 or the like is provided on the back surface 6 of the cantilever 1, and this protrusion 10 is brought into contact with a displacing object.
You are free to devise ways to make it easier to measure the displacement.

From a structural and morphological point of view, the free end 4 of the cantilever referred to in the present invention is compared to the fixed end 3, which is intentionally fixed stably and firmly. refers to an end that is intentionally configured to allow displacement. Therefore, if the free end 4 is mechanically connected to some fixed part by a fragile member, in other words, even if the free end 4 has a shape like a double-sided beam at first glance, a certain part If the structure is designed to allow the displacement of the free end, such a structure can be considered to substantially satisfy the cantilever structure according to the present invention, with the part corresponding to the free end. vinegar. As described above, when this is developed to detect displacement in two-dimensional directions, it may appear as a cantilever with a so-called diaphragm shape.

Next, considering the method for forming the resistance line 2, the resistance line 2 described above can be formed not only by doping with impurities as mentioned above, but also by forming it separately in advance as a resistance conductor in a predetermined shape. A mechanical method of attaching the created material to an insulating cantilever, a printing method of a resistive material according to a predetermined pattern on the cantilever, or a method of vapor deposition according to a predetermined pattern using an existing semiconductor process. It can also be formed by a method such as an epitaxial growth method.

[0026] In addition, conceptually, the minute displacement detector of the present invention consists of two basic components: a cantilever 1 that generates mechanical displacement, and a resistance line 2 provided on the cantilever. Even if there is, instead of using an insulating cantilever 1, it is possible to construct the cantilever with a resistive material whose resistance value changes due to the piezoresistance effect (for example, a semiconductor material of a predetermined conductivity type with an appropriate resistivity). In such a case, if the leads to the measurement system are taken out from two points spaced apart in the length direction of the cantilever, the minute displacement detection mechanism of the present invention described above will function as is. That is, in this case, the resistance line 2 is provided on the cantilever itself as a semiconductor cantilever made of a resistive material.

Furthermore, instead of the resistance line 2, it is also conceivable to use an insulating material line whose electromotive voltage changes due to the piezoelectric effect in response to the stress caused by minute displacement of the cantilever. In that case, the method of forming the insulating material line, the overall pattern, etc., can be applied almost as is with respect to the resistance line 2 that has been explained so far, and therefore, the present invention shown in FIGS. 1 to 8 In each example,
If the resistance line 2 in the figure is replaced with the insulating material line 2, each becomes a new embodiment of the present invention. Rochelle salt and barium titanate are suitable insulating materials that exhibit a corresponding electromotive force due to strain caused by minute displacements. In this case, considering the already known characteristics, it is possible to obtain a voltage value change of about 1 V for a minute displacement of 1 A (angstrom), which is a sufficient value for analysis. In addition, similar to the embodiment in which the resistance line is formed by the cantilever itself, the cantilever 1
If the cantilever 1 is made of an insulating material whose electromotive force changes due to piezoelectric effect in accordance with the stress caused by minute displacement, the insulating material line 2 provided on the cantilever 1 can also be constituted by the cantilever itself.

[0028]

Effects of the Invention In the minute displacement detector of the present invention, the most basic minute displacement detection system is constituted only by a cantilever and a resistance line or an insulating material line formed on the cantilever. First of all, it is significantly superior to the conventional example described above in that the structure is so simple that it cannot be cut any further. Naturally, the device configuration can be made smaller and vibration isolation becomes easier. Furthermore, a satisfactory detection sensitivity can be obtained, and since the configuration is simple, the accuracy of conversion into electrical quantity can be improved. In addition, in principle, it can be used in ultra-high vacuum environments and extremely low temperature environments, so it is expected to have a wide range of applications in the future.

[Brief explanation of drawings]

FIG. 1 is an explanatory diagram of the structure and operation of a basic embodiment of a minute displacement detector produced according to the present invention.

FIG. 2 is an explanatory diagram of the action of the minute displacement detector of the present invention when acceleration is applied.

FIG. 3 is a schematic configuration diagram of an embodiment of the present invention in which a resistance line is formed in a meandering shape.

FIG. 4 is a schematic configuration diagram of an embodiment of the present invention in which a plurality of resistance lines are formed.

FIG. 5 is a schematic configuration diagram of an embodiment of the present invention in which resistance lines are formed on the front and back surfaces of a cantilever, respectively.

FIG. 6 is a schematic configuration diagram of an embodiment of the present invention in which the shape of the cantilever is wedge-shaped.

FIG. 7 is a schematic configuration diagram of an embodiment of the present invention in which the cantilever is shaped like a triangular frame.

FIG. 8 is a schematic configuration diagram of an embodiment of the present invention in which a protruding tip is provided on a cantilever.

FIG. 9 is an explanatory diagram of the configuration and operation of a conventional example for detecting minute displacements using a tunneling electron microscope.

FIG. 10 is an explanatory diagram of the configuration and operation of a conventional example that detects minute displacements using an "optical lever."

[Explanation of symbols]

1 Cantilever 2 Resistance line or insulating material line 3 Fixed end 4 Free end 5 Cantilever surface 6　Back side of cantilever 8 Electrode 9 Support member

Claims (15)

[Claims] [Claim 1] Having a length between a fixed end and a free end,
An insulating cantilever that can be slightly displaced using the fixed end as a fulcrum; and a resistance line that is provided on the cantilever and whose resistance value changes due to a piezoresistance effect in response to the stress that accompanies the minute displacement of the cantilever. Micro displacement detector. 2. The minute displacement detector according to claim 1, wherein the resistance line has a strip-like pattern portion extending from the fixed end toward the free end on one surface of the cantilever. Features a minute displacement detector. 3. The minute displacement detector according to claim 1, wherein the resistance line is formed of two parallel strip patterns extending from the fixed end toward the free end on one surface of the cantilever. and a folded pattern part that electrically connects one of the lengthwise ends of the two strip pattern parts. 4. The minute displacement detector according to claim 1, wherein the resistance line includes three or more n lines extending parallel to each other from the fixed end to the free end on one surface of the cantilever. The strip-like pattern portions are electrically connected to the n strip-like pattern portions sequentially along the juxtaposition direction and alternately on one end side and the other end side in the length direction. 1. A minute displacement detector, comprising one folded pattern portion. 5. The minute displacement detector according to claim 2, 3 or 4, characterized in that a plurality of said resistance lines are provided. 6. The minute displacement detector according to claim 5; wherein the plurality of resistance lines are provided only on the one surface of the cantilever; At least some of the resistance lines are provided on the other surface of the cantilever opposite to the one surface. 7. The minute displacement detector according to claim 5 or 6, wherein at least some of the plurality of resistance lines are electrically connected to each other in series. displacement detector. 8. The minute displacement detector according to claim 5 or 6, characterized in that at least some of the plurality of resistance lines are electrically connected in parallel to each other. displacement detector. 9. The minute displacement detector according to claim 2, 3, 4, 5, 6, 7 or 8, wherein the resistance line is provided by pasting a resistance conductor to the cantilever. Features a minute displacement detector. 10. The minute displacement detector according to claim 2, 3, 4, 5, 6, 7 or 8, wherein the resistive line is provided by printing a resistive material on the cantilever. Features a minute displacement detector. 11. The minute displacement detector according to claim 2, 3, 4, 5, 6, 7 or 8, wherein the resistive line is provided by vapor deposition of a resistive material on the cantilever. Features a minute displacement detector. 12. A micro-displacement detector according to claim 2, 3, 4, 5, 6, 7 or 8, wherein the cantilever is made of an intrinsic or nearly intrinsic semiconductor material; and the resistive line is made of an intrinsic or nearly intrinsic semiconductor material. 1. A minute displacement detector, characterized in that it is provided by doping a cantilever made of an almost intrinsic semiconductor material with impurities. 13. The micro-displacement detector according to claim 1, wherein the cantilever, instead of being insulative, changes its resistance value due to a piezoresistance effect in response to stress accompanying its own micro-displacement. A minute displacement detector characterized in that the resistance line is the cantilever itself. [Claim 14] Claims 1, 2, 3, 4, 5, 6, 7
or 8. The minute displacement detector according to 8; wherein the cantilever is provided with an insulating material line in which the electromotive force changes due to a piezoelectric effect in accordance with the stress accompanying the minute displacement of the cantilever, instead of the resistance line. A minute displacement detector characterized by; 15. The minute displacement detector according to claim 14, wherein the cantilever is made of an insulating material whose electromotive force changes due to a piezoelectric effect in response to stress associated with minute displacement of the cantilever; and the insulating material line. is the cantilever itself; a minute displacement detector.