JPH03128414A - Inclination sensor - Google Patents

Abstract

PURPOSE:To obtain a sensor which is tough to electromagnetic disturbance and can be used even for a device which is objectionable to magnetism by detecting the difference of intensity of a transmitted light beam caused by the inclination of colored liquid instead of detecting the difference of magnetic flux caused by the inclination of magnetic fluid. CONSTITUTION:There is the homogeneous colored liquid 1 having a fixed light absorbing coefficient in a transparent container 2 in a rectangular parallelopiped shape. Light emitting elements(LD) 3 and 4 consisting of a laser diode, etc., are provided to be fixed on both ends of the bottom surface of the container 2 and attached so that light beams which have nearly identical intensity and are collimated each other may irradiate the upper surface of the container 2 at right angle to a horizontal direction. Light receiving elements(PD) 5 and 6 consisting of a phototransistor, etc., are attached on the upper surface of the container 2 so that they may receive the light beams L1 and L2 which are emitted from the LDs 3 and 4 and pass through the liquid 1. By taking the value of the output (a) of the light receiving intensity to the PD 5 as I1 and the value of the output (b) of the light receiving intensity of the PD 6 as I2 and measuring them by a connected measuring device, the inclination thetais obtained.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an inclination sensor, and particularly to an inclination sensor that can be applied to detect the inclination of a spirit level or an apparatus.

[Conventional technology]

As a conventional technique, for example, Japanese Patent Application Laid-Open No. 61-20791
As shown in Japanese Patent No. 5, there is a tilt sensor using a magnetic fluid and an open magnetic path magnetic core.

A conventional tilt sensor has an open magnetic path magnetic core with an excitation winding,
It consists of a container containing a magnetic fluid placed on an open magnetic circuit core.

FIG. 2 is a configuration diagram showing an example of a conventional tilt sensor.

The open magnetic path magnetic core has the excitation winding 7 in the center body of the U-shaped magnetic core 10,
The output windings 8, 9 are arranged on the legs 11.12, respectively. The container 14 is provided on the U-shaped magnetic core 10,
A magnetic fluid 13 is placed inside.

The magnetic fluid 13 is excited by the U-shaped magnetic core 10.

When the magnetic fluid 13 is tilted, the magnetic flux passing through it is changed, so the magnetic flux of the U-shaped magnetic core lO changes, and the output winding 8
, 9, and by measuring this differential output voltage, the tilt angle can be read out.

[Problem to be solved by the invention]

However, since the above-mentioned conventional tilt sensor detects changes in magnetic flux due to the tilt of the magnetic fluid, -
It has the drawback that it is susceptible to electromagnetic disturbances, and because the tilt sensor itself generates magnetism, it is difficult to use it in devices that dislike magnetism.

[Means to solve the problem]

The tilt sensor of the present invention includes a homogeneous colored liquid having a constant light absorption coefficient, a transparent container containing the colored liquid, and a plurality of tubes provided at both ends of one surface of the container that irradiates a light beam to the opposite surface. a first light-receiving element that receives light rays emitted from the first light-emitting element and passed through the colored liquid; It is configured to include a second light receiving element that receives the transmitted light beam.

〔Example〕

Next, embodiments of the present invention will be described in detail with reference to the drawings.

FIG. 1 is a block diagram showing an embodiment of the present invention.

The tilt sensor shown in FIG. 1 is fixed to a homogeneous colored liquid 1 having a constant light absorption coefficient, a rectangular parallelepiped-shaped transparent container 2 containing the colored liquid 1, and both ends of the lower surface of the transparent container 2. so as to irradiate the upper surface of the transparent container 2 with parallel light beams with almost the same intensity at right angles to the horizontal direction.
A light-emitting element consisting of an attached laser diode, etc.
(hereinafter referred to as LD) 3 and 4, and an LD on the top surface of the transparent container 2.
3. Light Ll irradiated from LD 4 and passed through colored liquid 1,
A light-receiving element (hereinafter referred to as PD) 5 consisting of a phototransistor or the like is installed to receive light L2, respectively.
, 6.

Next, the operation will be explained with reference to the drawings.

When the transparent container 2 is tilted at an angle of inclination θ with respect to the horizontal direction, L
The length of the light ray irradiated from D3 passing through the colored liquid 1 is H,
, the length of the light ray irradiated from LD4 passing through the colored liquid l is set as H2, and the distance between LD3 and LD4 is set as D. Also,
The intensity of the light rays emitted from LD3 and LD4 are respectively φ
. , the intensity of the light beam received by PD5 is φ1, the intensity of the light beam received by PD6 is φ2, and the light absorption coefficient of the colored liquid 1 is μ.

Generally known as Lambert's law,
Light that passes through a material with a constant light absorption coefficient has the property that the intensity attenuates exponentially with the thickness of the material. That is, the following equations (1) and (2) hold true.

φ1=φ. e-μm゛...
(1) φ2=φoe−“1′...
... (2) Also, the following equation (3) holds true geometrically.

Therefore, the following equation (4) is derived from equations (1) to (3).

Here, if the value of the received light intensity output a of PD5 is 1, and the value of the received light intensity output of PD6 is I2, then Il+I2 is φ
, 2φ2, so from equation (4) we get the following (5)
The formula is obtained.

As can be seen from equation (5), the slope θ can be determined by measuring Il and I2 with a measuring device (not shown) connected to the received light intensity outputs a and b.

In the above-mentioned embodiment, the tilt angle θ was calculated from the received light intensity ratio 11/L of the received light beam, but for example, the tilt angle θ and the received light intensity ratio I r / I 2 may be calculated in advance in the required range. The relationship is accurately measured and determined, and the actually measured received light intensity ratio I l / I 2 is obtained from the measured relationship value between the two.
The inclination angle θ may be obtained by calibrating by extrapolation or the like.

In addition, although the light emitting elements 3 and 4 were fixed to the lower surface of the transparent container 2, they were fixed to other members that do not perform tilting operations, and the transparent container 2 was irradiated with light, which passed through the colored liquid 1. The intensity of the received light is modified.

/I2 may be measured to obtain the inclination angle θ.

〔Effect of the invention〕

The inclination sensor of the present invention detects the difference in intensity of transmitted light due to the inclination of the colored liquid instead of detecting the magnetic flux difference due to the inclination of the magnetic fluid, so it is resistant to electromagnetic disturbance and does not generate magnetism. It has the advantage that it can be used in devices that dislike magnetism.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing an embodiment of the present invention, and FIG. 2 is a block diagram showing a conventional example. ■・・・Colored liquid, 2...Transparent container, 3
,4...LD,5,6...PD,7.
...Excitation winding, 8゜9...Output differential winding, IO...U-shaped magnetic core, 11゜12...
Legs, 13...Magnetic fluid, 14...Container, a, b...Received light intensity output.

Claims (1)

[Claims] A homogeneous colored liquid having a constant light absorption coefficient, a transparent container containing the colored liquid, and first and second light emitting elements each provided at both ends of one surface of the container and irradiating light beams to the opposite surface. a first light-receiving element that receives the light beam emitted from the first light-emitting element and passed through the colored liquid; and a first light-receiving element that receives the light emitted from the second light-emitting element and passed through the colored liquid. A tilt sensor comprising: two light receiving elements.