JP2002277242A - Apparatus and method for detecting tilt angle - Google Patents

Abstract

PROBLEM TO BE SOLVED: To measure the tilt angle with reduced error against the variation or change of the surface level of a liquid contained in a closed container, irrespective of the condition of the container. SOLUTION: The apparatus for measuring the tilt angle, relative to a measuring direction, comprises a glass tube 40 containing a liquid 41, an emitter 20 for emitting a laser beam, a half mirror 30 for deflecting the laser beam reflected from the liquid surface after the beam emitted from the emitter 20 permeates into the liquid 41 from its lower surface, a first and second cylindrical lenses 51, 52 for condensing the deflected laser beam, and a beam position detecting element 60 for measuring the position of the condensed laser beam.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a tilt angle detecting device and a tilt angle detecting method for detecting a tilt angle.
The present invention relates to a tilt angle detection device and a tilt angle detection method that are optimal for detecting a minute tilt angle based on the direction of gravity.

[0002]

2. Description of the Related Art Conventionally, a bubble level has been widely used to visually check whether or not a measurement surface is inclined from horizontal in order to level out construction equipment, precision equipment, various measuring instruments, and the like. ing. In this bubble tube level, for example, a liquid colored in a conspicuous color is put in a closed glass tube, and predetermined bubbles are contained when the liquid is sealed. Also, a mark such as a bubble reference line is provided on the glass tube, and the level of the measured object can be measured by visually confirming the position of the bubble with respect to this mark. is there.

[0003] However, this bubble level has to rely on human visual observation, which is insufficient for detailed measurement applications. In particular, in recent years, there has been a strong demand to detect the measured inclination angle as an electric signal convenient for controlling and monitoring the apparatus. Therefore, a technique of measuring a tilt angle by reflecting light on a liquid surface (a free liquid surface formed horizontally by gravity) and detecting the position of the reflected light has been studied.

[0004]

As described above, there is a technique for measuring a tilt angle by reflecting light on a liquid surface and detecting the position of the reflected light. There have been problems such as a lack of accuracy and an increase in the size of the measuring device.

FIGS. 6 (a) and 6 (b) are diagrams for explaining a problem of a tilt angle measuring apparatus which has been studied conventionally. FIG. 6A shows a case where incident light is applied to the liquid 202 contained in the closed container 201 from obliquely above, and measurement is performed. FIG.
2 shows a case in which incident light is applied obliquely from below to perform measurement. By irradiating the liquid surface from an oblique direction,
For example, it is possible to secure a place for a light source that generates a laser beam and a measurement unit that includes a sensor or the like that measures reflected light.

As shown in FIG. 6A, light is irradiated onto the liquid surface from above the liquid surface, and if the position of the reflected light from the liquid surface can be detected, the incident light and the surface of the liquid 202 can be detected. Becomes clear, and the inclination angle can be detected. However, as shown in FIG.
The adhesion liquid 203 exists inside 01. As a result, the light emitted from above the liquid surface is refracted by the attached liquid 203 in the closed container 201, and the reflected light obtained is
Due to the refraction of the light, there is a predetermined error with respect to the original reflected light. Therefore, it is difficult to accurately measure the inclination angle, and it is difficult to measure a minute inclination angle, for example, about 0.01 mm per 1 m.

On the other hand, as shown in FIG. 6B, by irradiating light from below the liquid surface, the problem of the adhered liquid 203 can be solved. However, the sealed container 201 and the liquid 202 change due to expansion or the like due to a rise in temperature, and the liquid level of the liquid 202 also changes. Also, the liquid level may vary from the beginning due to manufacturing errors and the like. FIG. 6B shows a state in which a change in the liquid level height h has occurred. When light enters the liquid level obliquely for the purpose of securing a place between the light source and the measuring unit, FIG. As shown in (b), the reflection position shifts, and the shift of the reflection position becomes an error, so that an accurate tilt angle cannot be measured.

Furthermore, if there is a tilt in a direction other than the direction to be measured, that is, in a direction orthogonal to the direction to be measured, the reflected light will be reflected according to the tilt. The light is also deflected in a direction orthogonal to the above, making it difficult to detect the light position.

Japanese Patent Application Laid-Open Nos. 2000-266545, 2000-105119, and the like disclose a large cross section of light from a light source composed of a laser beam, and allow free light through a dark field pattern. There is disclosed a technique of measuring the tilt of a tilt sensor by irradiating a liquid surface having a surface from a lower surface and reading reflected light with a two-dimensional tilt sensor. However, in the techniques described in these publications, since light is radiated through a dark field pattern, all the light cannot be radiated to the same position on the liquid surface, and an accurate reflection angle cannot be obtained. Further, since light is converted into a dot matrix using a dark-field pattern and the light is measured by a change in the dot matrix, the calculation becomes extremely large and the cost of the apparatus cannot be denied. Furthermore,
For example, it is not possible to cope with waving of the liquid surface due to vibration, and in such a case, it becomes difficult to perform arithmetic processing.

The present invention has been made to solve the above technical problems, and its object is not to be influenced by the state of a container for closing a liquid.
An object of the present invention is to measure an inclination angle while reducing an error with respect to variations and changes in the liquid level. Another purpose is
Even when tilted at right angles to the measurement direction, 1
It consists in condensing light on a two-dimensional light position detecting element.

[0011]

With this object in mind, an inclination angle detecting apparatus to which the present invention is applied is a light emitting means for emitting light, and reflects light emitted from substantially vertically below by the light emitting means. Level forming means for forming a liquid level for use, a deflecting means for changing the direction of light reflected from the liquid level formed by the liquid level forming means, and reflection from the liquid level formed by the liquid level forming means And a position measuring means for measuring the position of the light which is changed in direction by the deflecting means and condensed by the light collecting means.

Here, if the condensing means is formed by a plurality of lenses such as two cylindrical lenses, the degree of freedom in design can be improved and adjustment can be facilitated. It is preferred in that respect.

Further, the liquid level forming means may be characterized in that the liquid is sealed so that the liquid level is formed in a cylindrical tube formed of a transparent material. This cylindrical tube
It is made of glass or resin or the like, and it is not always necessary that the entirety be transparent. For example, a window or the like may be provided with a transparent material at least for a portion through which light is transmitted.
Further, the liquid surface is sufficient if it can form a horizontal surface,
In addition to the case where the liquid is formed between the liquid and the gas, the liquid surface may be formed by liquids having different specific gravities and separated from each other.

From other viewpoints, the tilt angle detecting device to which the present invention is applied includes a container containing a liquid, a light emitting unit for emitting laser light, and a laser light emitted from the light emitting unit. A half mirror that changes the direction of the laser light transmitted from below the liquid surface of the liquid and reflects the liquid surface, a cylindrical lens that collects the changed laser light, and a position of the collected laser light. And a light position detecting element for measurement.

Here, if this cylindrical lens is characterized by condensing a laser beam in a direction component orthogonal to a measurement direction in which an inclination angle is desired to be detected, an inexpensive one-dimensional light position detection is possible. This is preferable in that an element can be used. Further, the method is excellent in that the direction of the direction not targeted is not output as a detection error.

This cylindrical lens has a first
And a second cylindrical lens, wherein the first cylindrical lens reflects the liquid surface and deflects the diffused laser light into parallel light, and the second cylindrical lens includes the first cylindrical lens. The laser beam deflected into parallel light by a lens is focused on a light position detecting element. In addition, a plurality of cylindrical lenses may be provided.

On the other hand, the present invention relates to a tilt angle measuring method for measuring a tilt angle in a one-dimensional measuring direction, which comprises irradiating a liquid surface of a liquid sealed in a container with light from a substantially vertical downward direction. Light reflected by the surface is deflected, the deflected light is condensed in a direction orthogonal to the measurement direction, and the tilt angle is measured based on a change in the light irradiation position of the condensed light.

Here, the light reflected by the liquid surface is
The feature that the light is deflected in the measurement direction is preferable in that the distance between the liquid surface and the light irradiation position can be increased, and the detection sensitivity can be increased.

[0019]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, the present invention will be described in detail based on embodiments shown in the accompanying drawings. FIG. 1 is an explanatory diagram showing an overall configuration of a tilt angle detection device 10 which is a digital level. The tilt angle detection device 10 according to the present embodiment includes a light emitting unit 2 as an emission unit on a base 11.
0, a half mirror 30 as a deflecting unit, a glass tube 40 as a light reflecting unit, a first cylindrical lens 51 and a second cylindrical lens 52 as a plurality of cylindrical lenses as a condensing unit, and light as a position measuring unit. The position detecting element 60 is fixedly provided. Further, an electric signal processing unit 70 for converting an electric signal from the light position detecting element 60 into a voltage output that is easy to handle and outputting the converted voltage is provided.

The light emitting section 20 includes a semiconductor laser 21 as a light emitting element, a collimator lens 22 for forming parallel light, and a diaphragm 23 for stopping light. The semiconductor laser 21 is, for example, a laser diode with an output of 5 mW that emits red visible light, and the light emitted from the semiconductor laser 21 is a collimator lens 22 having a focal length of 5 mm, for example.
Collimation (parallel light). The collimated light is stopped down by the stop 23 so as to have a diameter of, for example, 0.6 mm. In the present embodiment, the laser light emitted from the light emitting unit 20 is configured to be emitted perpendicular to the reference surface of the base 11.

The laser light emitted from the light emitting section 20 is split by the half mirror 30 in the direction of the glass tube 40 which goes straight, and in the orthogonal direction (right direction in the figure) which is 90 degrees from the direction. However, the laser beam bent (deflected) in the orthogonal direction is not used. The transmitted laser beam that travels straight is applied to the glass tube 40.

The glass tube 40 is a cylindrical glass having an outer diameter of about 10 mm and a wall thickness of about 0.8 mm, in which a liquid 41 is sealed. In order to prevent volatilization and leakage of the liquid 41, the liquid 4
After inserting 1, both ends or one end are welded with glass to form a seal. The glass tube 40 may not be made of glass, but may be made of, for example, a transparent resin. Alternatively, only a region through which light is transmitted may be opened like a window. The liquid 41 is required to have an appropriate viscosity. This is because if the viscosity is high, the response becomes poor, and if the viscosity is low, bubbles are generated, which hinders accurate measurement. In the present embodiment, a colorless and transparent mixture of alcohol and ether is used.

The glass tube 40 contains about half of the liquid 41. That is, the lower half of the glass tube 40 is filled with the liquid 41, the upper half has an air layer, and the liquid surface exists at the boundary surface. The laser light that has passed through the half mirror 30 is incident on the glass tube 40, passes through the liquid 41, and is reflected on the liquid surface in the glass tube 40.

Here, when the reference surface of the base 11 is set horizontally, the laser light is emitted perpendicular to the reference surface of the base 11, so that the emitted laser light is generated by gravity. The light is vertically incident on the liquid surface (free liquid surface) formed horizontally, and is reflected vertically. Here, the light amount of the laser light reflected by the liquid surface is about 2% of the incident light amount. On the other hand, when the reference surface of the base 11 is tilted, the light emitting unit 20 and the half mirror 30 are fixedly provided with respect to the base 11, so that the laser beam is incident on the liquid surface with the tilt. You.
Therefore, the light reflected from the liquid surface changes according to the inclination. Here, when the inclination angle detecting device 10 is inclined by the angle θ, the light reflected on the liquid surface, which is the boundary between the liquid layer and the gas layer, is inclined by 2nθ, where n is the refractive index of the liquid 41. .

Actually, the liquid surface formed by gravity is always horizontal, and when the base 11 is tilted, each mechanism provided on the base 11 and the laser beam are tilted. However, for the sake of simplicity of description, the base 11 is placed horizontally, and the liquid level is relatively the same even if the description is made on the assumption that the liquid level is inclined according to the inclination of the base 11. Therefore, in the following description, for convenience of explanation,
These are used properly.

Further, the glass tube 40 of the present embodiment
Are intentionally inclined with respect to the horizontal.
FIG. 2 is a diagram showing a state where the glass tube 40 is attached while being inclined. As shown in FIG. 2, the glass tube 40
It is mounted at an angle R from the horizontal plane (for example, about 1 ° to 2 °). The laser light emitted from the light emitting section 20 as a light source is not only a liquid surface but also a glass surface (glass tube 4).
(Outside and inside 0). The reflectance from the glass surface is about 4 to 5%. In the present embodiment, since the glass tube 40 is tilted and attached, the reflected light is reflected in a direction different from the reflected light from the liquid surface, and the reflected light from the liquid surface which is originally required Can be prevented from being adversely affected.

As described above, in the present embodiment, since the laser beam is emitted from the lower side of the glass tube 40, even if the liquid 41 adheres to the inside of the glass surface on the upper portion of the glass tube 40, the measurement is performed. There is no adverse effect. In addition, since the laser light is irradiated perpendicular to the liquid surface, even if the height of the liquid surface changes, the optical path of the reflected light does not change, and no measurement error occurs.

Next, as shown in FIG. 1, the laser light reflected from the liquid surface of the glass tube 40 is incident on the half mirror 30, and is directed in the direction of the straight line and the direction of the light position detecting element 60 orthogonal to the direction (FIG. To the left). Here, the light in the straight traveling direction is not used. The laser light that has been split and deflected in the orthogonal direction (left direction in the drawing) is incident on the light position detecting element 60 via the first cylindrical lens 51 and the second cylindrical lens 52. As described above, by splitting the light by the half mirror 30, even when the liquid surface that is the reflection surface is irradiated with light substantially (substantially) perpendicularly, the light position detection element 60 is separated from the light emitting unit 20. Can be provided at the position.

In the present embodiment, the half mirror 3
A first cylindrical lens 51 and a second cylindrical lens 52 are provided on the optical path between the optical element 0 and the light position detecting element 60. The light split by the half mirror 30 is
The glass tube 40 also deflects and diffuses light in a direction orthogonal to the measurement direction. FIG. 3 is a diagram of the tilt angle detection device 10 shown in FIG. 1 as viewed from the right. This figure 3
Shows a direction orthogonal to the measurement direction, and shows a tilt from a horizontal plane with respect to the orthogonal direction. Thus, in the direction perpendicular to the direction in which the liquid level is measured,
When tilted at a predetermined angle, the laser reflected light from the liquid surface is
It is deflected according to the inclination. In addition, glass tube 4
Since 0 has a cylindrical shape, the reflected laser light is refracted and diffused in a line shape due to its curved surface shape.

FIG. 4 shows a first cylindrical lens 51.
FIG. 4 is a diagram for explaining a relationship between the first cylindrical lens and a second cylindrical lens. As shown in FIG. 4, the first cylindrical lens 51 is installed so as to convert the laser light deflected and diffused in a direction perpendicular to the measurement direction into parallel light. still,
The first cylindrical lens 51 and the second cylindrical lens 52 used in the present embodiment have a focal length of about 40 mm, and the first cylindrical lens 5
The distance from 1 to the light diffusion position, that is, the distance from the glass tube 40 is set to a focal length of about 40 mm.

The laser light having passed through the first cylindrical lens 51 is incident on the second cylindrical lens 52. The second cylindrical lens 52 is disposed so as to converge the incident laser light on the light position detecting element 60 which is a condensing position. Note that the distance from the second cylindrical lens 52 to the light position detecting element 60 is determined according to the focal length.
0 mm.

The first cylindrical lens 51 and the second cylindrical lens 52 optically correct deflection and diffusion of light in a direction orthogonal to the measurement direction as shown in FIG. Light can be collected on the detection element 60. Here, the cylindrical lens is
It has a refractive power in only one direction and does not affect the deflection of light in the measurement direction in this embodiment. That is, only the inclination in the measurement direction is detected, and the influence of the inclination in the direction orthogonal to the measurement direction is excluded, thereby serving to eliminate the measurement error. Thereby, the light position detecting element 60
Can adopt a cheap one-dimensional one, and
The glass tube 40, which is a container for enclosing the liquid 41,
It becomes possible to use an inexpensive cylindrical glass tube having a curved surface.

In the present embodiment, a plurality of cylindrical lenses (51 and 52) are used.
It does not require individual lenses. For example, with respect to deflection and diffusion in the direction perpendicular to the measurement direction by the liquid surface and the glass tube 40, the position on the optical path is adjusted by one cylindrical lens, and the light is focused on the optical position detecting element 60. In this case, the same effect can be obtained. It is preferable to reduce the number of cylindrical lenses in that the cost of the entire apparatus can be reduced.
However, in the case of using one cylindrical lens, the positional relationship among the glass tube 40, the light position detecting element 60, and the cylindrical lens is uniquely determined according to the focal length of the lens, and the design freedom is increased. The degree decreases.

On the other hand, with respect to the inclination of the liquid surface, the longer the distance between the liquid surface and the light position detecting element 60, the larger the displacement applied to the light position detecting element 60, that is, the change in the position of the light.
As a result, the sensitivity and resolution related to the angle for detection are increased. In the present embodiment, the distance between the liquid surface and the light position detecting element 60 is about 100 mm. If two cylindrical lenses (51 and 52) are used as in this embodiment, the first cylindrical lens 5
The laser light can be made into parallel light by 1 and the distance between the first cylindrical lens 51 and the second cylindrical lens 52 can be set arbitrarily.

Therefore, if two cylindrical lenses (51 and 52) are used as in the present embodiment, the liquid level and the light position detecting element 6 can be adjusted according to the required sensitivity and resolution.
It is possible to freely design the distance between zero. Also,
Since the lens optical system can be divided into the glass tube 40 and the first cylindrical lens 51, and the optical position detecting element 60 and the second cylindrical lens 52, respectively, there is an advantage that assembly adjustment is easy.

Next, the light position detecting element 60 will be described. The light position detecting element 60 is an element that emits an electric signal according to a position where light is irradiated. As mentioned above, 1
By using one or more cylindrical lenses,
One-dimensional light position detection element (PSD: Position Sensitive)
Device 60 can be used. Optical position detection element 6
Numeral 0 denotes a state in which the liquid surface is not inclined (that is, a state in which the reference surface of the base 11 is kept horizontal), and is arranged so that the laser beam is applied to the center of the light position detecting element 60. When the liquid surface is tilted (ie, when the reference surface of the base 11 is tilted), the direction in which the laser beam is reflected on the light position detecting element 60 changes because the direction of reflection of the laser light from the liquid surface changes.

In the present embodiment, the distance from the liquid surface to the light position detecting element 60 is about 100 mm. Therefore, for example, when the liquid surface is tilted 1/1000 (1 mm for 1 m), The light irradiation position of the light position detecting element 60 changes by 100 mm × (1/1000) × 2 × 1.5 = 0.3 mm. The incident angle is 1/1 with respect to the liquid surface.
000, the reflection angle is also 1/1000. Therefore, the amount of change becomes twice the slope, and
Due to the refractive power of the liquid 41 and the glass tube 40, 1.5
It is assumed that the angle changes.

Light position detecting element 60 used in the present embodiment
In consideration of such measurement conditions, when the light irradiation position on the light position detecting element 60 changes by 0.3 mm, the electric output from the light position detecting element 60 changes by about 5%. ing. When the light position detecting element 60 is used, for example, when the light position detecting element 60 is tilted 0.01 / 1000, the light irradiation position on the light position detecting element 60 changes by 3 μm, and the voltage output changes by 0.05%.

In the present embodiment, the laser light that has passed through the cylindrical lens is directly
However, it is also possible to provide a lens system between the light position detecting element 60 and the cylindrical lens to enlarge the change in the light irradiation position, and further collect the light.

Next, the electric signal processing section 70 will be described. FIG. 5 is a block diagram showing a configuration of the electric signal processing unit 70. The amount of change in the electric signal obtained from the optical position detection element 60 is extremely weak as described above, and noise may be mixed due to the ripples of the liquid surface generated by vibration due to disturbance. In the present embodiment, in consideration of such signal characteristics, first, the electric signal from the optical position detecting element 60 is converted into a predetermined voltage by the current-voltage conversion circuit 71, and is amplified by the amplification circuit 72. Noise removal is performed by the filter circuit 73. The signal from which the noise has been removed is converted into a voltage output that is easy to handle by the voltage output conversion circuit 74 and output to the output terminal. This electrical signal can be subjected to various signal processing depending on the application.

In the electric signal processing unit 70, for example,
Calculation processing for correction is performed by predetermined software. For example, when the tilt angle detection device 10 vibrates and the liquid surface of the glass tube 40 is wavy, the signal waveform obtained by the optical position detection element 60 is also wavy.
However, the electric signal processing unit 70 performs a predetermined operation such as taking an average value, thereby making it possible to obtain a measured value relating to a required inclination.

In the present embodiment, the light emitting section 20 is provided vertically below the glass tube 40 via the half mirror 30, and the light traveling straight through the half mirror 30 is incident on the glass tube 40. For example, it is also possible to provide the light position detecting element 60 vertically below the glass tube 40 so that the laser light emitted from the light emitting unit 20 is bent, deflected, and incident on the glass tube 40. However, in order to increase the distance of the light position detecting element 60 from the liquid surface in order to increase the sensitivity and the resolution, it is necessary to make the entire apparatus vertically long. In the case of a device that detects a minute angle, it is preferable that the device be long in the direction in which the angle is detected because it is necessary to accurately arrange the reference surface of the base 11 on the surface to be measured. Therefore, it is excellent to arrange each structure as shown in FIG.

As described in detail above, in the present embodiment, light is incident on the liquid surface from below perpendicularly, so that errors are small with respect to variations and changes in the liquid surface height. can do. Further, by using the half mirror 30, the light emitting unit 20 and the light position detecting element 60 can be provided in different places even when light is incident perpendicular to the liquid surface. Further, by providing the half mirror 30, it is possible to secure a large distance between the liquid surface and the light position detecting element 60, and the position change of the reflected light from the liquid surface is large at the light position detecting element 60. Thus, the detection sensitivity can be increased. In order to further enhance this effect, it is effective to provide a mirror or the like to lengthen the optical path.

In the present embodiment, at least one cylindrical lens (in the embodiment, the first cylindrical lens 51 and the second cylindrical lens 52) is provided between the liquid surface and the optical position detecting element 60. Was placed.
Thereby, even when the base 11 is tilted in a direction perpendicular to the measurement direction (see FIG. 3), the one-dimensional light position detecting element 6
Light can be converged on zero. As a result, cheap 1
A two-dimensional photodetector can be used, and a tilt in an untargeted direction does not become a detection error. For example, compared to a device that arranges a two-dimensional dark-field pattern on the optical path and measures the tilt angle based on the positional deviation, the error is extremely small, the device can be downsized, and simple signal processing can be performed. And an accurate measurement value can be obtained.

Further, for example, when the liquid surface is wavy due to vibration or the like, it is difficult to obtain a pattern at equal intervals because the cross section of light is large in the above-described two-dimensional dark field pattern measurement. , And the arithmetic processing cannot be performed. However, the light of the point (the cross section of the light is small) according to the present embodiment is transmitted to the cylindrical lenses (51 and 5).
By condensing in 2) and performing one-dimensional measurement, it is possible to measure an accurate tilt by a simple calculation.

The provision of the cylindrical lenses (51 and 52) makes it possible to use an inexpensive curved tube having a curved surface as described for the glass tube 40 in which the liquid 41 is filled. In general, the side of the container needs to be flat so that light passes straight through, and it is very costly to manufacture a closed container having a flat surface without curvature. In the glass tube 40 having a curved surface with low cost, the reflected light from the liquid surface is diffused and spread on the curved surface. However, by providing the cylindrical lens, the reflected light is correctly condensed on the optical position detecting element 60. can do. In addition, the light irradiated and reflected on the glass tube 40 can prevent the light from entering the light position detecting element 60 by arranging the glass tube 40 at an angle. Furthermore,
By providing a plurality of cylindrical lenses (51 and 52) and once converting them into parallel light, the degree of freedom in design is increased,
Adjustment can be made easier.

[0047]

As described above, according to the present invention,
The tilt angle can be measured without being affected by the state of the container that seals the liquid, and with less error for variations or changes in the liquid level.

[Brief description of the drawings]

FIG. 1 is an explanatory diagram showing an overall configuration of a tilt angle detection device that is a digital level.

FIG. 2 is a diagram showing a state in which a glass tube is attached by being inclined.

FIG. 3 is a view of the tilt angle detection device shown in FIG. 1 as viewed from the right.

FIG. 4 is a diagram for explaining a relationship between a first cylindrical lens and a second cylindrical lens.

FIG. 5 is a block diagram showing a configuration of an electric signal processing unit.

FIGS. 6A and 6B are diagrams for explaining a problem of a tilt angle measuring device that has been studied in the past.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 10 ... Inclination angle detection apparatus, 11 ... Base, 20 ... Light-emitting part, 21 ... Semiconductor laser, 22 ... Collimator lens, 2
3 ... Aperture part, 30 ... Half mirror, 40 ... Glass tube, 4
1 liquid, 51 first cylindrical lens, 52
A second cylindrical lens, 60 ... an optical position detecting element,
70: electric signal processing unit, 71: current-voltage conversion circuit, 7
2. Amplifier circuit 73 Filter circuit 74 Voltage output conversion circuit

Claims (8)

[Claims] 1. An emitting unit for emitting light, a liquid surface forming unit for forming a liquid surface for reflecting light emitted from substantially vertically below by the emitting unit, and a liquid surface forming unit. Deflecting means for changing the direction of light reflected from the liquid surface; condensing means for condensing light reflected from the liquid surface formed by the liquid surface forming means; And a position measuring means for measuring a position of the light condensed by the light condensing means. 2. The tilt angle detecting device according to claim 1, wherein the light collecting means is formed by a plurality of lenses. 3. The tilt angle detecting device according to claim 1, wherein the liquid level forming means is filled with liquid so that the liquid level is formed in a cylindrical tube formed of a transparent material. 4. A container containing a liquid, a light emitting unit for emitting a laser beam, and a laser beam transmitting the laser beam emitted from the light emitting unit from below the liquid surface of the liquid and reflecting the liquid surface. A half mirror that changes the direction of the laser light, a cylindrical lens that collects the laser light whose direction has been changed by the half mirror, and a light position detection element that measures the position of the laser light that is collected by the cylindrical lens. An inclination angle detecting device. 5. The apparatus according to claim 4, wherein the cylindrical lens focuses a laser beam in a component orthogonal to a measurement direction in which an inclination angle is desired to be detected.
The tilt angle detecting device according to the above. 6. The cylindrical lens includes a first cylindrical lens and a second cylindrical lens, and the first cylindrical lens converts the laser light reflected by the liquid surface and diffused into parallel light. 5. The optical system according to claim 4, wherein the second cylindrical lens deflects and converges the laser light deflected to parallel light by the first cylindrical lens on the optical position detecting element.
The tilt angle detecting device according to the above. 7. A tilt angle measuring method for measuring a tilt angle in a one-dimensional measurement direction, comprising irradiating light to a liquid surface of a liquid sealed in a container from substantially vertically below, and reflecting the liquid surface. Deflecting the deflected light, condensing the deflected light in a direction orthogonal to the measurement direction, and measuring an inclination angle by changing a light irradiation position of the condensed light. . 8. The tilt angle measuring method according to claim 7, wherein the light reflected by the liquid surface is deflected in the measuring direction.