JP2002039739A - Collision prevention sensor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To solve the problem that a conventional collision prevention sensor which is a contact sensor possibly collides against and breaks equipment and an object because of its inertia even when it is stopped immediately immediately after detection and the operation efficiency of the equipment becomes low when the moving speed is made slow to prevent the collision. SOLUTION: This collision prevention sensor which is made subminiature has a proximity sensor, a contact sensor 2, and their processing circuit 4 adjacently on the same substrate and can stop the equipment immediately after contacting is detected by the contact sensor 2 by reducing the moving speed of the equipment on detecting an approach to an object through the proximity sensor 3.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an anti-collision sensor, and more particularly to a high-performance anti-collision sensor applied to equipment driven at a very small distance from an object.

[0002]

2. Description of the Related Art Generally, in a device such as a high-magnification microscope objective lens which needs to be driven at a very small distance from an object, the object always comes into contact with the device, and the object or the device is always in contact. There is a risk that either will be damaged.

In the case of a high-magnification microscope objective lens, the risk of contact with an object to be observed can be avoided by mounting an autofocus function. If it fails, there is still a risk of breakage. For this reason, it is desirable to carry out an interlock by mounting a collision prevention sensor.

For such applications, an optical distance measuring sensor may be used. However, there are cases where accurate distance measurement cannot be performed depending on the state of the surface of the object, and a mechanical contact sensor is most desirable. .

As such a contact sensor, for example, Japanese Patent Application Laid-Open No. 11-118636 discloses a contact sensor constituted by a piezoelectric element and an electrode.

[0006]

Generally, the contact between the objective lens and the object is not strictly kept parallel, so that such a contact sensor is located close to the object and the objective lens. It must be placed between the object and the objective. In addition, in the case of a contact type sensor, even if the device is stopped immediately after detecting the contact, if the moving speed is high, the device cannot be stopped due to inertia and collide, and the device or the object is damaged. there is a possibility. This problem can be avoided by sufficiently reducing the moving speed, but this leads to a problem that the operation efficiency of the device is reduced.

[0007] These problems can be solved by increasing the moving speed when the distance between the device and the object is large, and decreasing the moving speed after the device is approached to some extent. That is, by combining the contact sensor and the proximity sensor, efficient operation can be performed while minimizing damage to the device or the target object.

Usually, however, the distance between the objects of the high-magnification objective lens, that is, the work distance is 0.2 mm.
In the following cases, there is no sensor that can be arranged in such a narrow space and has both functions of a contact sensor and a proximity sensor.

Accordingly, an object of the present invention is to provide an ultra-compact anti-collision sensor which can be arranged in a very small space and has a proximity detecting function.

[0010]

In order to achieve the above object, the present invention provides a flat substrate, a first sensor for detecting an approach of an object provided on the substrate in a non-contact manner, A collision prevention sensor is provided on the substrate in proximity to the first sensor, the second sensor detecting contact with the object. The collision prevention sensor is a contact sensor that is provided on a substrate and detects a distortion generated in the substrate by contact with the object, and detects contact with the object. The contact state with the target object is detected by comparing the set first threshold value and the second threshold value.

In the collision prevention sensor having the above-described configuration, the proximity sensor and the contact sensor are arranged on the same substrate, so that a very small size and a high S / N ratio can be obtained, and the proximity sensor approaches the object. Then, the moving speed of the device is reduced, and the device is stopped immediately after the contact is detected by the contact sensor.

[0012]

Embodiments of the present invention will be described below in detail with reference to the drawings. FIG. 1 shows an example of a contact sensor that can be mounted on the tip of a microscope objective lens as a first embodiment of a collision prevention sensor according to the present invention. This embodiment has a rectangular shape as a shape suitable for attachment to a microscope objective lens. However, when it is attached to another member, it is needless to say that the shape is adapted to each. FIG. 1A is a view of the contact sensor as viewed from the front, FIG. 1B is a cross-sectional configuration of a portion taken along the line AA ′ in FIG. 1A, and FIG. , B- in FIG.
The cross-sectional configuration of the portion B 'is shown.

The collision prevention sensor 1 comprises a contact sensor 2,
The first N-type single-crystal silicon thin plate 5 on which the proximity sensor 3 and the processing circuit 4 having the CMOS structure are formed, and the second N-type single-crystal silicon thin plate 7 on which a plurality of electrodes 6 are formed, are provided. These N-type single-crystal silicon thin plates are connected by a polyimide film 8 formed integrally with them. The polyimide film 8 is configured by laminating a lower polyimide film 8a and an upper polyimide film 8b.

In this contact sensor 2, a U-shaped slit 9 is opened in the first N-type single-crystal silicon thin plate 5, and a cantilever-shaped portion 1 supported by only one side is formed.
0 is formed. On the surface of the portion 10, a projection 11 made of polyimide having a flat top surface is formed, and on the surface of the first N-type single-crystal silicon thin plate 5 of the supporting portion of the portion 10, a bridge circuit 12 is formed. Two P-type diffused resistors 12a, 12b, 12c, 12d are arranged.
The cantilever-shaped portion 10 is formed to be thinner than other regions of the first N-type single-crystal silicon thin plate 5.

The P-type diffused resistors 12a to 12d are connected to the processing circuit 4 by wires 16 formed in the polyimide film 8 as described later. On the other hand, the proximity sensor 3
Is composed of a coil 13 formed on the first N-type single-crystal silicon thin plate 5 and covered with the polyimide film 8,
The processing circuit 4 is connected from both ends of the coil 13 by a wiring 14.
It is connected to the.

When an object having conductivity comes close to the coil 13 in a state where an electric current flows, the inductance of the coil 13 changes and is detected, and the approach of the object can be detected. A region 15 between the first N-type single-crystal silicon thin plate 5 and the second N-type single-crystal silicon thin plate 7
Is made of only the polyimide film 8 and therefore has sufficient flexibility, and can be bent freely at this portion.

FIG. 2A is an enlarged view of the region of the P-type diffused resistors 12a to 12d shown in FIG.
(B) shows a cross-sectional configuration of a CC ′ portion of FIG. 1. These resistance elements 12a to 12d are connected by a wiring 16 to form a bridge circuit. FIG.
As shown in (b), the wiring 16 is formed of the lower polyimide film 8a.
The lower polyimide film 8a is electrically connected to the P-type diffusion resistor 12 by a contact hole 17 opened at a predetermined portion of the lower polyimide film 8a. The upper part of the wiring 16 is covered with an upper polyimide film 8b.

In this configuration, when the object comes into contact with the tip of the projection 11, the cantilever-shaped portion 10 is pushed down, causing distortion in the area of the bridge circuit 12. Due to this distortion, the balance of the bridge circuit 12 is broken and the output changes. By detecting this change, contact with the object can be detected. Since the gauge factor of a semiconductor diffusion resistor is considerably larger than that of a normal metal film resistor, etc., the strain measurement is performed by measuring the change in the resistance value of the diffusion resistor formed on the semiconductor substrate. , High contact detection sensitivity can be obtained. Although not shown in FIG. 1, the wiring 16 is connected to the processing circuit 4.
It is connected to the.

Next, the operation of the processing circuit 4 will be described. The processing circuit 4 measures the change in inductance of the coil 13 and the output of the bridge circuit 12. More specifically, a self-excited oscillation circuit using the coil 13 is formed, and a function for obtaining a change in the oscillation frequency and an A / D converter after a predetermined bridge voltage is applied to the bridge circuit 12 to amplify an output signal.
Perform the conversion. As described above, since the processing circuit 4 is formed very close to the bridge circuit 12 (contact sensor 2) and the proximity sensor 3 on the same semiconductor substrate, sensing with a high S / N ratio of proximity or contact can be performed.

Next, FIG. 3 shows an example in which such a collision prevention sensor is mounted on the tip of a microscope, and the actual operation will be described. The anticollision sensor 1 is formed by bending an N-type single-crystal thin plate 5 on an upper surface 20 near a lens 19 in a lens frame 18 of a high-magnification objective lens of a microscope in a region 15 made of a polyimide film. The side of the mold single-crystal silicon thin plate 7 (the contact sensor 2 and the proximity sensor 3) is attached and mounted on the side surface 21 of the lens frame 18.

The electrode 6 of the collision prevention sensor 1 is connected to an external controller via a lead wire (not shown) to control a focusing operation. By arranging the electrode 6 on the side surface of the lens frame 18 as described above, it is possible to prevent a substantial increase in the thickness of the contact sensor in order to secure a space for connecting lead wires. For this reason, the contact sensor according to the present embodiment can be applied to a high-magnification objective lens in which the distance between the frontmost lens 19 of the objective lens and the object is very small.

The operation of the collision prevention sensor 1 mounted on the microscope will be described. The stage on which the object of the microscope is placed approaches the objective lens at a high speed. However, when the object is a conductor, the inductance of the coil 13 arranged in the collision prevention sensor 1 changes with the approach. The circuit 4 detects the information, transmits the information to an external controller, and reduces the speed at which the stage (not shown) approaches.

When the projection 11 comes into contact with the object while approaching the object while decelerating further, the output of the bridge circuit 12 changes. When this output information is transmitted to the external controller via the processing circuit 4, the stage is immediately stopped.
Since the change in the inductance of the coil 13 depends not only on the distance between the sensor and the object, but also on the conductivity of the object and the environmental temperature, it is difficult to accurately determine the distance to the object. From the range of the conductivity of the object and the environmental temperature, etc., a threshold value is determined in advance within a range where collision does not occur, and when the threshold value is reached, control is performed to start deceleration, without increasing the time required for focusing. In addition, it is possible to prevent the object from jumping out and damage to the object or the objective lens due to inertia.

The operation of this embodiment when the object is a cell or the like will be described. When observing cells or the like with a microscope, the observation may be performed with oil or the like interposed between the microscope and the objective lens. In this case, the stage on which the object immersed in oil is placed on the upper surface approaches the objective lens at high speed. When the projection 11 comes into contact with the liquid surface and the stage further rises, surface tension acts on the top surface of the projection 11 to push down the projection 11. At this time, bridge circuit 1
The stage is once decelerated by detecting the distortion occurring in 2.

Thereafter, when the projection 11 comes into contact with the object, the projection 11 is pushed down more strongly, and a large output fluctuation occurs in the bridge circuit 12. When the output fluctuation is detected, the movement of the stage is immediately stopped. By temporarily decelerating the stage when it comes into contact with the liquid surface in this way, it is possible to avoid jumping out of the object due to inertia and damage to the object or the objective lens without greatly increasing the time required for focusing. Can be.

FIG. 4 schematically shows the output characteristics of the sensor when such cell observation is performed. Two threshold values are provided for the output signal of the bridge circuit 12 in the present embodiment. That is, the threshold value m is the protrusion 1
1 is a value smaller than the output signal due to the surface tension when contacting the liquid surface. The threshold value n is larger than the output signal due to the surface tension when the protrusion 11 contacts the liquid surface, and smaller than the intensity of the output signal when the protrusion 11 contacts the object.

Normally, an output signal due to contact with an object is much larger than an output signal due to surface tension, so that a sufficiently high strain measurement sensitivity is obtained so that an output signal due to surface tension can be stably detected. What is necessary is just to optimize a structure so that it may be performed. At this time, since the surface tension acting on the projection 11 when it comes into contact with the liquid surface is proportional to the peripheral length of the contact surface, the top surface of the projection 11 should be flat as in this embodiment. This makes it possible to increase the detection sensitivity of the surface tension.

As described above, according to the collision prevention sensor of the present embodiment, when the object is mounted on a microscope, the object is used both when the liquid is interposed between the conductor or the objective lens and the object. Therefore, by having the two functions of proximity detection and contact detection to the object, it is possible to effectively prevent damage to the device (the objective lens in this embodiment) or the object due to the collision. .

Although the above embodiments have been described, the present specification also includes the following inventions.

(1) A first sensor for detecting, in a non-contact manner, an approach between a planar substrate and a mating object provided on the substrate, and a first sensor provided on the substrate in close proximity to the first sensor. And a second sensor for detecting contact with the object.

(2) The first sensor according to (1), wherein the first sensor has a coil and a circuit for detecting a change in inductance of the coil, and detects an approach to an object based on the change in inductance. It is a collision prevention sensor.

(3) The second sensor has a pressure receiving portion protruding above the substrate, and a distortion detecting mechanism for detecting the weight of the substrate around the pressure receiving portion, and the distortion detecting mechanism contacts the object. The collision prevention sensor according to the above mode (1), which detects a collision.

(4) The first sensor is a collision prevention sensor according to the above item (1) or (2), which has a circuit for detecting an inductance formed on a semiconductor substrate.

(5) The second sensor has an electric circuit formed on a substrate made of a semiconductor, and detects a change in current or voltage generated in the electric circuit due to distortion of the substrate. The collision prevention sensor according to the above item (1) or (3).

(6) The collision sensor according to the above (5), wherein the electric circuit is a bridge circuit.

(7) The upper surface of the pressure receiving portion of the first sensor is
The collision prevention sensor according to the above (1), which is a substantially flat surface.

(8) A sensor provided on the substrate for detecting distortion generated in the substrate due to contact with the object and detecting contact with the object, wherein the amount of distortion to be detected is set to a first preset value. This is a collision prevention sensor that compares the threshold value and the second threshold value to detect a contact state with an object.

(9) The first threshold is the amount of distortion caused by the contact of the contact sensor with the surface of the liquid.
The threshold value is a distortion amount generated by contact with a solid object, and is a collision prevention sensor according to the above mode (8).

[0039]

As described in detail above, according to the present invention, it is possible to provide an ultra-compact collision prevention sensor which can be arranged in a very narrow space and has a proximity detection function.

[Brief description of the drawings]

FIG. 1 is a diagram showing a configuration example according to an embodiment of a collision prevention sensor according to the present invention.

FIG. 2 is a diagram illustrating a configuration example of a bridge circuit illustrated in FIG. 1 and a cross-sectional configuration thereof.

FIG. 3 is a diagram illustrating an example in which the collision prevention sensor according to the present embodiment is mounted on the tip of a microscope.

FIG. 4 is a diagram schematically illustrating output characteristics of the sensor when a cell is observed by mounting the collision prevention sensor of the present embodiment on the tip of a microscope.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Collision prevention sensor 2 ... Contact sensor 3 ... Proximity sensor 4 ... Processing circuit 5 ... 1st N type single crystal silicon thin plate 6 ... Electrode 7 ... 2nd N type single crystal silicon thin plate 8 ... Polyimide film 8a ... Lower layer polyimide Film 8b Upper polyimide film 9 Slit 10 Part 11 Projection 12 Bridge circuit 12a, 12b, 12c, 12d P-type diffused resistor 13 Coil 14 Wiring 15 Area

Continued on front page F-term (reference) 2F051 AA00 AB06 AC07 BA07 2F063 AA23 AA25 AA50 BA30 BB02 BD15 CA08 CA28 CA35 CA40 DA01 DA02 DA04 DA05 DA23 DB03 DD02 DD08 EC03 EC06 EC14 EC15 EC20 EC22 GA05 GA27 LA04 LA19 LA27 2F068 AA A44 DD27 DD30 GG02 GG04 GG06 GG20 HH09 JJ06 JJ13 JJ25 JJ30 MM04 NN08 RR03

Claims (3)

[Claims] A first sensor for detecting an approach of an object provided on the substrate in a non-contact manner; a first sensor provided on the substrate in proximity to the first sensor; And a second sensor that detects contact with the object. 2. The method according to claim 1, wherein the first sensor has a coil and a circuit for detecting a change in inductance of the coil, and detects an approach to the object based on the change in inductance. Item 2. The collision prevention sensor according to Item 1. 3. A sensor provided on a substrate, for detecting a strain generated on the substrate by contact with the object, and detecting contact with the object, wherein the amount of distortion to be detected is set in advance. A collision prevention sensor that detects a contact state with an object by comparing with a first threshold value and a second threshold value.