JP5229813B2 - Tilt detection device using liquid crystal - Google Patents

Description

The present invention relates to a tilt detection device using liquid crystal using liquid crystal. The liquid crystal is usually aligned so that the orientation of adjacent liquid crystal molecules does not change significantly. However, in the liquid crystal, there may be a portion where the alignment is discontinuous with respect to the adjacent liquid crystal molecules, and the one where the discontinuous portions are arranged side by side is called a tilt. .
The present invention relates to a tilt detection device using liquid crystal utilizing an orientation distribution generated around the tilt in the liquid crystal.

  The tilt detector is used to check whether the ceiling, floor, etc. are tilted with respect to the horizontal. Bubbles are mixed in a container filled with liquid and tilted by the movement of the bubbles. There exist some which investigate the presence or absence of (for example, patent documents 1-3).

  However, examples using various liquids as tilt detection media can be found, but examples using liquid crystals as tilt detection media are not found.

JP-A-62-121308 JP 58-180907 A JP 2001-227947 A

  SUMMARY OF THE INVENTION In view of the above circumstances, an object of the present invention is to provide a tilt detection device using liquid crystal that can detect tilt using liquid crystal.

  The tilt detection device using the liquid crystal according to the first aspect of the present invention is a container having a flat reference surface formed on the outer surface, a liquid crystal sealed in the container, and a movement immersed in the liquid crystal so as to be movable. The relative position change of the moving body when the container is brought into contact with a non-horizontal plane with respect to the reference position where the moving body is stationary when the body and the reference plane of the container are brought into contact with a horizontal plane The liquid crystal is characterized in that an orientation distribution equivalent to that when there is a tilt at the position of the moving body is formed in the liquid crystal.

  According to the first invention, when the reference surface of the container is brought into contact with the ceiling, the floor surface or the like, if the floor surface or the like is non-horizontal, the moving body moves from the reference position, so that the inclination can be detected. it can. In addition, the sensitivity to tilt can be increased or decreased by adjusting the orientation distribution formed in the liquid crystal and adjusting the force to keep the moving body stationary at the reference position.

It is a schematic explanatory drawing of the inclination detection apparatus 1 using the liquid crystal of this invention, (A) is a schematic perspective view, (B) is a schematic sectional drawing in the state which mounted the container 2 on the floor surface FL. (A) is a schematic top view of the container 2, (B) is a schematic explanatory drawing of orientation distribution of liquid crystal LC. This is a schlieren photo of a liquid crystal with tilt. It is the figure which modeled the orientation of the liquid crystal molecule in the circumference of inclining.

Next, an embodiment of the present invention will be described with reference to the drawings.
The tilt detection apparatus using the liquid crystal according to the present invention is characterized in that the tilt detection medium uses a liquid crystal in which a tilt that is a liquid crystal defect is formed.

First, before explaining the tilt detection apparatus using the liquid crystal according to the present invention, the tilt will be described.
Fig. 3 is a photo of a schlieren of a liquid crystal with tilt (exhibited by C. Destrader, H. -T. Nguyen, H. Gasparoux, J. Malthete, and AM Levelunt, Mol. Cryst. Liq. Cryst., 71 , 118, (1981) Figure 2.233).
The tilt refers to a field defect of the alignment vector in the liquid crystal, that is, a discontinuous line. In FIG. 3, the alignment of the liquid crystal molecules is discontinuous with respect to the surrounding liquid crystal molecules along the direction perpendicular to the paper surface. It is formed by the lined portions existing in a line. In FIG. 3, the portion where the white and black belt-like structures intersect (the portions A and B in FIG. 3) is the defect nucleus, that is, where the spatial distortion of the direction of the liquid crystal molecules becomes the highest in the tilting. Note that the discontinuity of orientation with respect to surrounding liquid crystal molecules means that the orientation in the plane of the paper cannot be defined at that position. For example, in FIG. 3, the liquid crystal molecules are aligned in the direction perpendicular to the paper surface, that is, the direction toward the outside of the paper surface, or the alignment order is lowered.
Hereinafter, the direction in which the portions where the alignment of the liquid crystal molecules is discontinuous is arranged is referred to as the axis direction of tilting.
Fig. 4 shows a model of the orientation of liquid crystal molecules around the tilt (Exhibition: Liquid Crystal Dictionary). In FIG. 4, the portion represented by the point P is the position where tilting exists. In FIG. 4, the solid line indicates the alignment field around the tilt, and the liquid crystal molecules are aligned along the solid line so that the alignment direction is continuous. In addition, S in FIG. 4 has shown the intensity | strength of a defect, and it means that intensity | strength becomes so strong that the absolute value is large, The code | symbol represents the positive / negative of the defect.

Next, an inclination detecting device using the liquid crystal of the present invention will be described.
FIG. 1 shows an example of an inclination detection apparatus 1 using a liquid crystal according to the present invention. FIG. 1A is a schematic plan view, and FIG. 1B is a schematic cross-sectional view. 2A is a schematic plan view of the container 2, and FIG. 2B is a schematic explanatory diagram of the orientation distribution of the liquid crystal LC. Note that the solid line described in the liquid crystal LC in FIG. 2B indicates the alignment field around the tilt.
In FIG. 1, the code | symbol LC has shown the liquid crystal. The liquid crystal LC is, for example, a nematic liquid crystal, a smectic liquid crystal, a cholesteric liquid crystal, a discotic liquid crystal, or the like, and any liquid crystal LC may be used as long as it can cause tilting, and is not particularly limited.

  In FIG. 1, reference numeral 2 denotes a container in an inclination detection apparatus 1 (hereinafter simply referred to as the inclination detection apparatus 1) using the liquid crystal of the present invention. The container 2 is formed in a substantially square shape, and one surface thereof is formed as a flat reference surface 2h. The reference surface 2h is a surface that is brought into contact with the wall surface WL, the floor surface FL, or the like that detects inclination, and is formed on a flat surface. Note that the container 2 only needs to have a flat reference surface 2h, and the liquid crystal LC can be freely deformed.

  Further, the container 2 has a hollow space inside. The upper and lower surfaces of the hollow space of the container 2 are formed to be flat surfaces parallel to the reference surface 2h. The liquid crystal LC as described above is sealed inside the hollow space of the container 2, and the moving body 3 is disposed in the liquid crystal LC.

The liquid crystal LC includes a liquid crystal so that the movable body 3 is positioned at a position of the central axis CL of the container 2 (hereinafter referred to as a reference position) when the reference surface 2h of the container 2 is brought into contact with a horizontal surface. The orientation distribution formed in the LC is adjusted.
Specifically, when the reference surface 2h of the container 2 is brought into contact with a horizontal surface, the liquid crystal LC is adjusted so as to form an orientation distribution equivalent to that when there is a tilt at the reference position. Yes. For example, the surface of the moving body 3 and the inner surface of the container 2 are processed so that an alignment distribution as shown by a solid line is formed in the liquid crystal LC of FIG. Then, when the reference surface 2h of the container 2 is brought into contact with a horizontal surface, a tilt can be formed at the reference position in the liquid crystal LC. Therefore, in the state where no external force is applied to the moving body 3, The moving body 3 can be placed at the center of the hollow space (FIG. 2B).

In addition, as long as the moving body 3 is a substance having a difference in specific gravity from the liquid crystal LC, a material having a specific gravity larger or smaller than that of the liquid crystal can be used. For example, a fluid that does not react with the liquid crystal LC such as bubbles or water, or a solid such as metal or plastic can be used. When the alignment distribution as shown in FIG. 2B is formed in the liquid crystal LC, if the moving body 3 is solid, the surface of the moving body 3 and the inner surface of the container 2 are subjected to rubbing treatment, vertical alignment agent, etc. What is necessary is just to process. If the moving body 3 is a fluid, an alignment distribution as shown in FIG. 2B can be formed in the liquid crystal LC by mixing a surfactant with the fluid.
Furthermore, the alignment distribution formed in the liquid crystal LC is not particularly limited, and for example, any of the alignment distributions shown in FIG. 4 can be adopted. If the defect strength (indicated by S in FIG. 4) is increased, the force for holding the moving body 3 at the tilting position (position P in FIG. 4) can be increased, and the defect strength ( By weakening (indicated by S in FIG. 4), it is possible to weaken the force for holding the moving body 3 at the tilt position. That is, if the defect intensity of the orientation distribution formed in the liquid crystal LC in the container 2 is changed, the sensitivity of the inclination detecting device 1 can be adjusted.

  In FIG. 1, the moving body 3 is of a size that contacts both the upper surface and the lower surface, but the moving body 3 is only on either the upper surface or the lower surface. The magnitude | size of the grade which contacts may be sufficient. If the size of the moving body 3 is such that it only contacts either the upper surface or the lower surface, the moving body 3 moves along one of the surfaces sandwiching the liquid crystal LC. The orientation in the liquid crystal LC may be adjusted so that it can move.

  Furthermore, as shown in FIG. 1, the container 2 is provided with a known light source 5 such as an LED that irradiates light to the liquid crystal LC in the container 2, and is opposed to the light source 5 with the liquid crystal LC interposed therebetween. An observation window 2w through which the inside of the container 1 can be observed from the outside is formed on the surface. The center of the observation window 2w is formed so as to substantially coincide with the center of the hollow space of the container 2. That is, in a state where no external force is applied to the moving body 3, the observation window 2w is formed so that the moving body 3 is positioned at the center of the observation window 2w.

  Outside the observation window 2w, there is provided a detector 11 of a detecting means 10, such as a CCD camera, for photographing the moving body 3 in the liquid crystal LC through the observation window 2w. The detector 11 is connected to the inclination calculation unit 12. The inclination calculation unit 12 is configured so that the reference surface 2h of the container 2 is in contact with the amount of movement from the reference position of the moving body 3 detected by the detector 11 and the position thereof and the parameters stored in advance. The inclination of the floor surface FL or the like is calculated. The parameters stored in advance are, for example, properties such as rigidity of the liquid crystal LC itself in the container 2, strength of tilting formed in the liquid crystal LC, physical properties and weight of the moving body 3, and the like.

Next, a method of using the tilt detection apparatus 1 as described above will be described.
Hereinafter, a case where a moving body having a specific gravity smaller than that of the liquid crystal LC is used will be described. However, when a moving body having a specific gravity larger than that of the liquid crystal LC is used, the moving direction of the moving body 3 is reversed. Needless to say.

  First, before measuring the inclination, the reference surface 2h of the container 2 is placed in surface contact with a horizontal surface, and the moving body 3 is adjusted so as to be positioned at the center of the observation window 2w.

  In the inclination measurement, the adjusted inclination detection device 1 is disposed on the floor surface FL or the like where the inclination is to be measured. At this time, the container 2 is arranged such that the reference surface 2h is in surface contact with the floor surface FL or the like.

  If the floor surface FL on which the inclination detecting device 1 is disposed is horizontal, the direction of gravity applied to the moving body 3 is perpendicular to the lower inner surface or upper inner surface of the container 2. Then, the buoyancy generated in the moving body 3 works only in the direction perpendicular to the lower inner surface or the upper inner surface of the container 2, so that the moving body 3 is kept stationary at the center of the observation window 2 w.

On the other hand, when the floor surface FL or the like is inclined with respect to the horizontal, the direction of gravity applied to the moving body 3 is inclined with respect to the lower inner surface or the upper inner surface of the container 2, so that the buoyancy generated in the moving body 3 is It also has a component force in a direction parallel to the lower inner surface or upper inner surface of the container 2 (hereinafter simply referred to as a parallel component of buoyancy). Then, if the force applied to the moving body 3 from the liquid crystal LC, that is, the force applied to hold the moving body 3 at the center of the observation window 2w becomes larger than the parallel component force of the buoyancy, the moving body 3 It moves in the direction of the parallel component force.
Since the force applied from the liquid crystal LC to the moving body 3 increases as the moving amount of the moving body 3 from the center of the observation window 2w increases, the position where the parallel component of buoyancy and the force applied from the liquid crystal LC to the moving body 3 are balanced. Thus, the moving body 3 stops.

The moving body 3 is photographed by the detector 11, and based on the image photographed by the detector 11, the inclination calculating unit 12 calculates how much the moving body 3 has moved from the central part of the observation window 2w. Since the parallel component force of the buoyancy applied to the moving body 3 increases or decreases in proportion to the inclination of the floor surface FL or the like, the inclination angle of the floor surface FL or the like can be calculated based on the amount of movement of the moving body 3.
In addition, since it can be confirmed in which direction the moving body 3 has moved from the image photographed by the detector 11, the inclination direction of the floor surface FL or the like can also be calculated.

  If the weight and volume of the moving body 3 and the strength of the tilt formed on the liquid crystal LC are adjusted, the tilt that can be detected by the tilt detection device 1 can be freely adjusted. For example, if the strength of the tilting is increased, the force to keep the moving body 3 at the original position (center of the observation window 2w) is increased, so that the tilt angle can be detected even if the tilt is large. On the contrary, if the strength of the tilt is weakened, the force to keep the moving body 3 at the original position (the central part of the observation window 2w) is weakened. Can be detected well.

  The container 2 is provided with electrodes and magnetic poles, and an electric field and magnetic field are applied to the liquid crystal LC from the electrodes and magnetic poles, thereby adjusting the viscosity of the liquid crystal LC and the force exerted on the object 3 by the liquid crystal defect, etc. May be adjusted freely. This is preferable because the liquid crystal LC can be brought into an optimum state at the site where the inclination is inspected.

As shown in FIGS. 1 and 2, if the observation window 2w is provided with a scale or the like, it is possible for a person to visually observe and judge the inclination angle and the inclination direction without providing the detection means 10. It is.
Further, the light source 5 is not necessarily required, and may be omitted if the moving body 3 can be detected or visually confirmed only by the external light irradiated inside from the observation window 2w.
Furthermore, if the detector 11 is disposed in the container 2 at a position facing the light source 5, the observation window 2w may not be provided.

  The tilt detection apparatus using the liquid crystal according to the present invention is not limited to a floor surface but can be used as an apparatus for inspecting a tilt of a vertical wall surface or the like.

DESCRIPTION OF SYMBOLS 1 Inclination detection apparatus 2 Container 2h Reference plane 2w Observation window 3 Moving body 10 Detection means LC Liquid crystal

Claims (1)

A container having a flat reference surface formed on the outer surface;
Liquid crystal sealed inside the container;
A moving body immersed so as to be movable in the liquid crystal;
A relative position change of the movable body when the container is brought into contact with a non-horizontal plane is detected with respect to a reference position where the movable body is stationary when the reference plane of the container is brought into contact with a horizontal plane. A detection means,
The liquid crystal
Utilizing liquid crystal, the liquid crystal is adjusted so that when the reference surface of the container is brought into contact with a horizontal surface, an orientation distribution equivalent to that when a tilt is present at the reference position is formed. Tilt detection device.