JPS5960333A - Pressure detector - Google Patents

Abstract

PURPOSE:To obtain a simple, small-sized pressure detector which has various response characteristics by varying the quantity of transmitted light by the displacement of a slit provided to a pressure pedestal, and displaying pressure on a voltmeter in a state of balance with the electromagnetic resiliency of the voltage of a photodetecting element. CONSTITUTION:When pressure is applied to the pedestal 1, the optical slit 7 fitted at one end of a supporting rod 2 is displaced at the same time, and this optical slit 7 is disposed crossing the optical path of an optical displacement detector 12. The quantity of light is converted photoelectrically by the photodetecting element 8, amplified by an amplitude amplifier 13, and added to a reference signal from an external terminal by an adding circuit 14, whose sum signal is amplified by an amplifier 15, flowed through an electromagnetic coil 5, and converted by a precise resistance 16 into a voltage value, thereby displaying the value on a meter 17. The slit stops when the resiliency of the electromagnetic coil 5 and the pressure balance with each other and the pressure is detected by conversion to the pressure value. Various shapes are applicable to light transmission windows of the optical slit 7 and a fixed slit 10 according to the purpose of use by changing function relations between the extent of relative displacement between the both and the quantity of transmitted light.

Description

DETAILED DESCRIPTION OF THE INVENTION According to the present invention, the pedestal has a repulsive force against pressure applied from the outside.17. This relates to a pressure sensor configured to maintain its position at a predetermined position.

Conventionally, the means used to control the position of the pedestal in the pressure detector in this building is to electrically or (mechanically) detect the amount of positional displacement, and to adjust the position electromechanically using a feedback system using an ilr and sub-circuit. It was a precision measurement method for this rounding and displacement of the pedestal.

Alternatively, it is difficult to realize feedback circuit characteristics that are often nonlinear, resulting in expensive, complicated, and large devices. In addition, the amount of displacement of the pedestal can be detected mechanically.
When detection is performed in stages, the sensitivity decreases due to friction, etc., and in the case of electromagnetic detection, it is not easy to linearize the detection signal.To address these problems of the conventional method, the present invention is described below. It has special @.

(1) The movable base including the pressure detector cradle, the electromagnetic coil for generating repulsive force, and the position detection device) are configured to function without contact. The sensitivity of the pedestal is high. Furthermore, it is easy to adapt the shape and mass of the pedestal to the amplitude and frequency (acceleration) of the Cairo to be detected.

(2) Optical displacement J+L LII due to the movement of the movable table
The signal generated by the detector can be arbitrarily set depending on the shape of the optical slit attached to the two movable stands and the detector body. Therefore, even if an electronic circuit with simple feedback circuit characteristics is used, feedback with complex nonlinear characteristics can be applied to the movable platform.
The optimum feedback i of the vibration system can be easily set and adjusted.

(3) Optical displacement value detection devices can be made very small by using current micro-optics technology and microfabrication technology used in semiconductor processes. Since it is possible to make it NC, the pressure sensitive part can be downsized in addition to the above-mentioned feature 1.0.

Next, the operating principle of Ippon-J Maki's IIIJ will be explained based on an example. An example is shown in FIG. Prior to detecting the external pressure, set the zero calibration position to the cradle 1. A movable base 4 consisting of a support rod 2 and an electromagnetic core 3 is levitated to a predetermined position by passing an electric current through an electromagnetic coil (5) installed so as to have nine turns around the electromagnetic core written in %IJ. At this time, the current flowing through the coil is applied from the external terminal 6, and this current value is taken as the reference A1a at which the displacement of the pedestal is zero (zero pressure).

Next, when an I:F force is applied to the front NL cradle from the outside, a positional displacement occurs in the movable table, and the optical slit 7, which can be accessed at one end of the support ear, is simultaneously displaced. This optical slit connects the light emitting element 1 to the light receiving element 9. Fixed slit 1q
Optical displacement detection device consisting of 1] optical path 1 of 2! : Distributed W- in a crosswise manner. Also.

The shapes of the light transmitting windows of the optical slit and the fixed slit are determined with a specific relationship, and a large change in the amount of light is caused on the light receiving element surface due to a slight displacement of the optical slit. In addition, it is possible to set a change in the amount of light having an arbitrary relationship with the amount of displacement of the optical slit.

Now, 1. Normally, the change in light amount is set to increase with respect to the displacement of the movable table due to positive pressure. This amount of light is photoelectrically converted by the light receiving element and sent to an amplitude amplifier 13. The signal amplified to an appropriate amplitude by the amplifier is applied to an adder circuit 14 and added to the reference signal from the external terminal. The signal added to the reference signal is sent to the gravity amplification amplifier 15, where it is amplified to a size sufficient to operate the electromagnetic coil, and then applied to the coil pc. 2. The current flowing into the electromagnetic coil is converted into a voltage value using, for example, a precision resistor 16 that serves as a reference. meter 17
It is displayed on a display device 18 such as the one shown in FIG. When a current generated by the pressure applied to the pedestal is applied to the 0iS electromagnetic coil, the movable pedestal is repelled by a higher pressure and stops when the repulsive force and the pressure reach an equal magnitude. At this time, the optical displacement detection device 18 generates a large number of occurrences, and the electric circuit,
Flow through the said coil? Since ti and θIl: are constant values, the strength of the pressure can be detected by converting these values into pressure values.

Next is one of the features of the present invention. Displacement detection using an optical slit and generation of a nonlinear foot signal will be explained.

In FIG. 2, the horizontal axis represents the displacement X of the movable table, and the vertical axis represents the output of the displacement layer detection device (the size of i, Sfc, which is 0).

The straight lines a and b in the same figure are for pressure and displacement, which change proportionally, and have the same characteristics as a pressure indicator using a coil spring, etc. Q, a is for high sensitivity, and b is for a wide dynamic range. represents. If we take the high sensitivity characteristics shown in a to an extreme, we get
Although it is possible to realize a force detector in which the displacement of the movable base is extremely large, there is a problem in accuracy due to sensitivity to minute pressure detection.

Here, the pressure detection resolution is the percentage of the applied pressure.
It is said that the detection port can be detected up to the point. If we consider relative resolution and generate a feedback plate that keeps the resolution constant, we will need non-linear characteristics as shown in Figure C. By using this characteristic, it is possible to detect minute pressures and to reduce the displacement length of the movable base. Furthermore, ↓ Una 4j shown in figure d? By setting a linear characteristic, it is possible to set an insensitive area to minute pressure, that is, a threshold value. This characteristic is effective as a method for removing pressure noise. Furthermore, d
If we extend the characteristic of , and use a staircase waveform characteristic like that shown in e in the same figure, the output signal will be l? ll: Changes numerically.

Digital I (i'T fil:
It is. The characteristics shown in Figures a to e are typical examples of feedback, and these characteristics 4! (If used with gold, 7:lI combination W, it will be more complicated
It is possible to output 1 file. In addition, the feature that the feedback ht can be set arbitrarily is that
Non-direction of electrical signals and repulsive force in magnetic coils etc. 11;! It can also be used to correct the relationship;
This has the effect of facilitating IC circuit design. 2nd) Figure (
a), (b) K Optical slits 7a, 7b-7e for determining the characteristics of a-e shown in FIG.
, fixed sulin)・10. +, 10b . . . 10e, and the configuration of an optical system based on the basic principle of the Aigami correlation equation.

In the optical system shown in Figure (b) K, as the optical slit 7 moves, the degree of overlapping of the aperture with the fixed slit (+0) changes, and the total amount of light passing through these two slits changes in a complicated manner. It is something to do.

If the amount of movement (displacement) of the slit is expressed by the aperture function of each slit (f(x), gfx), and the total amount of light is expressed by an integral symbol, then the output light amount ■ becomes a function of the variable τ.

It can be expressed as. However, the coordinate axes of X and T are in the same direction, and (1 represents the beam width. Equation (1) is f (
x) and g(x), and the output signal of the displacement-feed detection device used for feedback shown in FIG. Borrowing is the ability to use 0]'. f(x), g
To create (x), there is an area chart method that changes the area of light passing through two areas, or a trans-average lens method that controls the amount of transmitted light, but using microfabrication technology. The area chart method is promising for realizing miniaturization of one slit.

Figure 4 is a (/q diagram) showing an example of an optical displacement measuring device using a reflecting mirror (1). Also, install 2 okiya slits (], Of, 10g).

The optical reflecting mirror changes the passing position of the light beam between the two slits. The optical reflecting mirror is attached to the movable table, and when pressure is applied to the pedestal, it moves in the direction of the arrow in the figure.

As a result, the light beam reflected by the reflecting mirror is displaced as shown by the dotted line, producing a result equivalent to a relative movement of the fixed slit.

The advantage of the method using a reflecting mirror is that it is not necessary to attach a slit to the I=TIII stand 111, so the slit can be easily replaced. In other words, when measuring while changing the detection sensitivity, response characteristics, etc. using the same pressure sensor, it is possible to easily replace the two sets of 16J fixed slits without affecting the moving parts. be.

The present invention has the above-described configuration, and by using an optical position measuring device that has arbitrary output characteristics with respect to the intensity of pressure to be detected, it is possible to easily create a pressure detector having 4+1 response characteristics. Moreover, it has a small size that can be realized by miniaturization. In addition, in the 2nd text theory jjlJ, the movable platform is levitated by the 1st accent, which should be the standard value, and the zero position + E
11i in the direction in which the JE force is applied.
If a force exists and the movable platform is installed laterally
, I, it is inconvenient to use it. It is also possible to use a permanent magnet in the electromagnetic core as a way to strengthen the repulsive force and reduce the current flowing through the electromagnetic coil. Furthermore, the pressure applied from the outside can be detected whether it is positive or negative, and the current that should be the reference value is set depending on the positive or negative pressure intensity. In this case, the movable platform has a
Apply bias pressure using gravity, electromagnetic horns, or mechanical force such as a spring to adjust from 10 to zero.

[Brief explanation of the drawing]

FIG. 1 is a diagram showing an embodiment of the present invention, and FIG. 2 is a diagram illustrating an embodiment of the displacement amount detection device in relation to the displacement of the movable base (-1) and the output of the optical displacement detection device. 1 is the pedestal, 2e is the support, 3 is the magnetic core, 4 is the pedestal, the support, ■ Can the L magnet be made up of 1a? , l1 unit, 5 is an electromagnetic coil, 71 is an optical slit, 8 is an older photo element, 9 is a light receiving element, 10 is a fixed slit, 11 is a lens, 12
Optical displacement 111 detection device I consisting of the optical slit, a light emitting element, a light receiving element, a fixed slit, and a lens. Knee [shi] 3 [-z) 1 (1')) Punishment, 3 giant 1 (b)

Claims (1)

[Claims] 1. A pedestal (1) and a support (2) provided integrally with the pedestal.
)and. % hardness on the strut 1. / J and R' + magnetic core (:
1), a light emitting element (8), an optical slit (7), and a fixed slit provided to optically and non-contact detect the minute displacement M' of the movable table. (
1+11, a lens (+1), and a light receiving element (9). an electromagnetic coil (
5) and: a pressure detector equipped with a display device W (u4) that measures and displays the value of the current flowing through the electromagnetic coil. 3. A pressure detector according to Patent No. 1i+'f, I4j, IJA, characterized in that: 3. A pressure detector according to Patent No. 4. The pressure detector according to claim 1, wherein the electromagnetic core (3) is a permanent magnet.