JP2508139B2 - Liquid level detector - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial field of use] The present invention relates to a liquid level detection device effective for visually detecting the liquid level position of a liquid stored in a container.

[Prior Art] Various techniques for detecting the liquid level of a liquid stored in a container have been conventionally known. As such,
For example, the following technologies have been proposed. That is, (1) a light-transmitting body including a substantially mountain-shaped prism portion extending in a direction in which the liquid level in a container that stores the liquid is varied, and a light-transmitting body is disposed so as to be spaced apart from and facing the light-transmitting body in a horizontal direction "Liquid level display device" comprising the reflected plate and a display device for displaying the liquid level in the container by the reflective plate and the translucent body (Japanese Utility Model Publication No. 62-7031).

(2) A resistor provided on a support body that rotatably supports a float arm connected to a float floating on the liquid surface, and a main slide that slides the resistor according to the rotation of the float arm. A "liquid level detector" that includes a child and detects the liquid level position by a change in electric resistance (Japanese Utility Model Publication No. 62-28127).

(3) A linear change of the float that includes an electric resistance substrate arranged in the vertical direction and a float that moves up and down along the electric resistance substrate in accordance with a change in the liquid level, "Liquid amount detecting device" (Japanese Utility Model Laid-Open No. 62-28129) that takes out as a displacement of electric resistance.

[Problems to be Solved by the Invention] However, the above-mentioned conventional techniques have the following problems, which are still insufficient. That is, (1) the configuration in which the movement of the float that moves up and down together with the liquid level is detected by converting it into a change in electrical resistance or the like has a mechanically movable portion that transmits or converts the movement of the float. A relatively large mounting space is required inside. Therefore, it is difficult to apply to a relatively small container such as a fuel tank of a motorcycle or a kerosene tank of a household stove, and there is a problem that versatility is deteriorated as the device is downsized.

(2) Further, when the liquid surface position is converted into an electric signal for detection, an indicator that operates in response to the electric signal such as a meter for displaying the detection result is required, and the device configuration becomes complicated. However, there is also a problem in that a mounting space for the display device is required and the mountability is deteriorated. This has been a particularly serious obstacle when applied to a container arranged in a moving body such as a fuel tank of a motorcycle.

(3) Furthermore, since the structure having mechanically movable parts requires precise positioning and predetermined part accuracy, there is a problem in that the number of parts and manufacturing man-hours of the device increase, and the work efficiency decreases. It was

(4) In addition, when the container is mounted on a moving object such as a vehicle, heat, vibration, acceleration, etc. from the outside are applied, so that the reliability and durability of the device deteriorate. there were.

(5) Further, in a configuration using an optical element such as a prism, it can be observed only from the side surface direction of the container, and not particularly from the upper surface, so the workability of liquid level detection is lowered, and moreover, it is measured visually. In this case, the brightness needs to be higher than a predetermined level, so that it is extremely difficult to measure the liquid surface position without illumination, for example, at night, and there is also a problem that the visibility of the liquid surface is deteriorated.

It is an object of the present invention to provide a liquid level detection device that suitably displays the liquid level position of a liquid stored in a container with excellent visibility using a small device.

Configuration of the Invention [Means for Solving the Problems] The present invention made to solve the above problems is a liquid level detection device for detecting the liquid level of a liquid stored in a container, wherein: An optical element which is arranged in a direction intersecting with the liquid surface and which changes a traveling direction of light directly irradiated from a predetermined light emitting position to a predetermined predetermined direction, and the optical element which is arranged at the light emitting position, A light source that illuminates the inside of the container; and a diffusion member that is arranged in the predetermined direction on the outer peripheral portion of the container and that receives and scatters light whose traveling direction is changed by the optical element. The gist of the invention is a liquid level detection device.

The optical element is arranged inside the container in a direction intersecting with the liquid surface, and changes the traveling direction of light directly irradiated from a predetermined light emitting position to a predetermined direction. For example, it can be realized by a reflection hologram produced by irradiating a recording material with a spherical wave that is a reference light emitted from the light emitting position and a parallel plane wave that is an object light traveling in a predetermined direction from the opposite surface. Alternatively, for example, a transmission hologram may be formed by making the object light and the reference light incident from the same surface of the recording material. Furthermore, for example, a known diffraction grating and an optical filter may be combined.

The light source is arranged at a light emitting position to illuminate the inside of the container. For example, it can be realized by a monochromatic light source such as a light emitting diode that outputs light of a predetermined wavelength. Also, for example,
A discharge lamp such as a metal halide lamp or a sodium lamp, or a visible light such as a fluorescent lamp may be used. Further, for example, it may be configured by one that emits infrared rays or ultraviolet rays.

The diffusing member is arranged in a predetermined direction on the outer peripheral portion of the container and receives and scatters the light whose traveling direction is changed by the optical element. For example, it can be realized by a frosted glass plate or the like. Further, for example, it may be a scattering screen. Furthermore, for example, when a light beam other than visible light, ultraviolet light, or the like is emitted from the light source, it can be made of frosted glass coated with a fluorescent substance. Further, for example, it may be a glass plate provided with a guide member that regulates the direction of light rays.

[Operation] In the liquid level detection device of the present invention, the traveling direction of the light emitted directly from the light source installed at the predetermined light emitting position inside the container for storing the liquid is changed to the direction intersecting the liquid level inside the container. The arranged optical element changes to a predetermined direction, and the diffusing member arranged in the predetermined direction on the outer peripheral portion of the container receives and scatters the light whose traveling direction is changed. work.

That is, of the light radiated from a predetermined position inside the container that stores the liquid, the light directly radiated without passing through the liquid by the optical element having an angle selectivity or the light radiated through the liquid inside. One of the lights is selected, the traveling direction is changed, and the light is guided to the outer peripheral portion of the container and scattered.

Therefore, the liquid level detection device of the present invention has a simple device configuration and serves to clearly display the liquid level of the liquid stored in the container.

As described above, the technical problems of the present invention are solved by the operation of each component of the present invention.

[Embodiment] Next, a preferred embodiment of the present invention will be described in detail with reference to the drawings. FIG. 1 shows a schematic configuration of a liquid level detection device which is an embodiment of the present invention.

As shown in the figure, a liquid level detection device 1 includes a light emitting unit 4 which is disposed inside a container 3 that stores a liquid 2 and illuminates the inside of the container 3, and inside the container 3 is substantially orthogonal to the liquid level. The container 3 in a direction that is opposite to the light emitting unit 4.
The hologram dry plate 5 is provided on the side surface of the hologram reflection plate 5 and reflects the light emitted from the light emitting unit 4, and the display unit 6 is provided on the upper surface of the container 3 to scatter the light reflected from the hologram dry plate 5. .

The light emitting unit 4 has a light emitting chamber 10 having an ON / OFF confirmation window 10a for judging whether or not a power source (not shown) is turned on, and a light emitting unit which is disposed inside the light emitting chamber 10 and emits monochromatic light of a predetermined wavelength. The diode 11 and the light emitting diode 11 are provided with a cylindrical lens 12 which collects light from the diode 11 and diffuses it in a direction toward the hologram dry plate 5 in a direction perpendicular to the plane of the drawing and guides it to the hologram dry plate 5.

The hologram dry plate 5 is composed of a glass plate 13 as a substrate and a dairy material 14 as a photosensitive material applied on one side of the glass plate 13, and the side to which the dairy material 14 is applied is adversely affected by moisture or the like. By the cover glass 15,
After heating in vacuum, it is completely sealed in dry gas.

The display section 6 is composed of a guide louver 16 arranged to prevent ambient light and a slide guide plate 17 for diffusing the reflected light from the hologram dry plate 5.

The hologram dry plate 5 is produced by exposure with the Lippmann hologram optical system 21 shown in FIG. In the optical system 21, first, the coherent laser light output from the laser 22 is split by the beam splitter 23 to create two coherent light waves. One light beam consists of mirrors 24, 25,
The direction is changed by, the light is condensed by the objective lens 26 and the pinhole 27, and the light travels in the direction indicated by the arrow E in the figure, and the dry plate 28 and the emulsion 29 coated on the back surface of the dry plate 28 are irradiated as reference light. The other light is converted in direction by the mirrors 30 and 31, is condensed by the objective lens 32 and the pinhole 33, is expanded by the lens 34 to be a parallel light beam, and then proceeds in the direction indicated by the arrow F in FIG. The dry plate 28 and emulsion 29 are irradiated as object light. Here, the reference light and the object light interfere with each other, and a hologram is formed by developing and fixing the interference. The hologram thus produced has a characteristic of reflecting only the incident light from the arrow E direction in the arrow F direction, that is, so-called angle selectivity. The position of the light emitting diode 11 with respect to the hologram dry plate 5 shown in FIG. 1 is the same as the position of the pinhole 27 in FIG. That is, it has so-called wavelength selectivity that reflects only light of a specific color in a specific direction. Therefore, the first
The light output from the light emitting diode 11 shown in the figure must be light having a wavelength substantially equal to the wavelength of the laser shown in FIG. 2 or light containing a wavelength substantially equal to the wavelength of the laser.

When displaying a wavelength different from that of the laser light at the time of making, the angle at the time of making is shifted in advance so that the light of the wavelength is reflected by the display unit 6, or
It is necessary to change the thickness of the hologram dry plate 5 by swelling or shrinking the emulsion in the developing / drying process after exposure.

The liquid level detection device 1 having the above configuration operates as follows. That is, as shown in FIG.
Of the light emitted from the inside, the light incident on the inside of the liquid 2 changes its traveling direction due to the difference in refractive index between the air inside the container 3 and the liquid 2, and as shown by arrows A and B in the figure, Since the incident angle on the hologram dry plate 5 changes, it does not reflect. On the other hand, of the light emitted from the light emitting diode 11, the light traveling in the air inside the container 3 is incident on the hologram dry plate 5 at a predetermined predetermined incidence, as indicated by arrows C and D in FIG. Since the light enters at an angle, it is reflected and reaches the display unit 6. Therefore, the direction indicated by the white arrow X in FIG.
When observing the display unit 6 from above, the light incident on the range from the bottom surface of the container 3 to the liquid surface position of the liquid 2 is not reflected by the hologram dry plate 5, so that the display unit 6 displays black.
On the other hand, light incident on the range from the liquid surface position of the liquid 2 to the upper surface of the container 3 is reflected by the angle selectivity and the wavelength selectivity of the hologram dry plate 5, so that the display unit 6 has a wavelength matching the wavelength selectivity. It is displayed in a predetermined color according to. In this way, the change in the liquid surface position of the liquid 2 in the container 3 is detected by the change in the position of the boundary line between the black portion of the display unit 6 not illuminated with light and the portion illuminated with light of a predetermined color. it can.

In this embodiment, the hologram dry plate 5 corresponds to an optical element, the light emitting diode 11 corresponds to a light source, and the frosted glass plate 17 corresponds to a diffusing member.

As described above, according to this embodiment, the liquid level detection device 1 can be downsized, and the liquid level display visibility can be improved.

This means that, for example, it is difficult to secure a sufficient mounting space for the liquid level detection device 1 inside or around the tank, and it is relatively difficult to visually confirm the display unit 6 of the liquid level detection device 1. , For example, a motorcycle fuel tank that needs to detect the position of the liquid level at night, in a dark room, etc.
Or, when applied to kerosene tanks of oil stoves,
It is suitable.

Further, the display unit 6 is provided with a guide louver 16 and a ground glass plate.
Since the reflected light from the hologram dry plate 5 is scattered by the frosted glass plate 17, the detection result displayed is the same no matter which angle the observation is performed, and the measurement error caused by the difference in the observation position is Does not happen. Therefore, the observer can always accurately observe the display of the liquid surface position from a relatively wide angle range above the liquid surface detection device 1 without causing parallax due to the difference in viewpoint.

Further, since the liquid level detection device 1 has a light emitting diode 11 for irradiating the light emitting section 4 with light of a specific wavelength, and the hologram dry plate 5 has both angle selectivity and wavelength selectivity,
An environment where the brightness required for liquid level detection cannot be secured, for example,
Even at night, the liquid surface position clearly displayed by the specific color corresponding to the specific wavelength can be visually and accurately detected without using a night-vision device or the like.

Further, when the light emitting diode 11, the hologram dry plate 5 and the display unit 6 are arranged in a predetermined positional relationship inside the container, the liquid level can be detected without fail, so that the display unit is located at the most observable position of the container, for example, on the upper surface. Since 6 can be arranged, the liquid level can be easily detected.

Furthermore, a simple device configuration consisting of the light emitting diode 11, the hologram dry plate 5 and the display unit 6 is sufficient, and since there is no part that requires accurate positioning, mechanically moving parts, etc., damage due to wear and deterioration does not occur. The reliability and durability of the liquid level detecting device 1 are improved, and the number of assembly steps of the liquid level detecting device 1 can be reduced by reducing the number of parts.

Further, as long as it is a container that stores a liquid in which the light emitted from the light emitting diode 11 is refracted, the liquid can be applied to all regardless of whether it is transparent or colored, and thus has a highly versatile liquid level. The detection device 1 can be provided.

Further, the light emitting diode 11 consumes less power and generates less heat than, for example, a halogen lamp or the like, and thus is suitable for mounting.

In this example, the display unit 6 was provided on the upper surface of the container 3. However, for example, the display unit may be provided on the side surface of the container 3. That is, the light emitting unit 4 and the hologram dry plate 5
Is constructed in the same manner as in the previously described embodiment, and the hologram dry plate 5
The side wall of the container 3 on the back side of the above is configured similarly to the display unit 6 described above. In this case, since the light is transmitted from the hologram dry plate 5 and the cover glass plate 15 from the bottom surface of the container 3 to the liquid surface, the display portion becomes bright, and from the liquid surface to the upper surface of the container 3, the light is emitted from the hologram dry plate 5. Since it is reflected and not transmitted, the display becomes dark. Even with this structure, the same effect as that of the above-described embodiment can be obtained.

Further, in this embodiment, the display unit 6 is arranged on the upper surface of the container 3. However, for example, as shown in FIG. 3, it may be arranged on the side surface of the container 43. That is, as shown in the figure, the liquid level detection device 41 is a container for storing the liquid 42.
A light-emitting unit 44 disposed inside 43 to illuminate the inside of the container 43,
A hologram that is installed inside the container 43 at a position that is substantially orthogonal to the liquid surface and that faces the light emitting unit 44, and that is provided on a side surface of the container 43 and that transmits irradiation light from the light emitting unit 44. It is also possible to configure the display unit 46 made of a glass plate provided on the side wall of the container 43 on the back surface side of the dry plate 45 and the hologram dry plate 45.

The light emitting unit 44 has the same configuration as that of the above-described embodiment,
The hologram dry plate 45 is a transmissive hologram and changes the optical path of only light incident from a specific angle in a predetermined direction. Further, the display unit 46 allows the transmitted light from the hologram dry plate 45 to pass through and protects the hologram dry plate 45.

With the above configuration, the liquid level detection device 41 operates as follows. That is, of the light emitted from the light emitting diode 51 and condensed by the cylindrical lens 52, the liquid 42
The light incident on the inside changes its traveling direction due to the difference in the refractive index between the air inside the container 43 and the liquid 42, and as shown by arrows G and H in the figure, differs from the predetermined incident angle on the hologram dry plate 45. Since the light is incident at an incident angle, it is transmitted, and the traveling direction is hardly changed and the light exits obliquely downward from the container 43 via the display unit 46. On the other hand, of the light emitted from the light emitting diode 51 and condensed by the cylindrical lens 52, the light traveling in the air inside the container 43 is directed to the hologram dry plate 45 as shown by arrows I and J in the figure. Since the light enters at a predetermined angle of incidence, the traveling direction of the light is changed to a direction substantially orthogonal to the hologram dry plate 45 and the light exits in a direction parallel to the bottom surface of the container 43. Therefore, when observing the display unit 46 from the direction shown by the white arrow Y in the figure, that is, from the side of the container 43, the light incident on the range from the bottom surface of the container 43 to the liquid surface position of the liquid 42 is the hologram dry plate 45. Since the course cannot be changed at the time of transmission due to the angle selectivity and wavelength selectivity of the display unit 46, the display unit 46 is displayed dark, while the light incident on the range from the liquid surface position of the liquid 42 to the upper surface of the container 43 is a hologram dry plate. Since the course is changed to a direction substantially orthogonal to the hologram dry plate 45 by the angle selectivity and the wavelength selectivity when transmitting 45, the display section 46 is displayed brightly. Thus, the position of the liquid surface can be detected even by using the transmission hologram dry plate 45.

Further, in the present embodiment, the light emitting diode 11 is configured to irradiate monochromatic visible light, so that the liquid surface position is determined by the display unit 6.
It was displayed in the single color, and the visual visibility was improved.
However, for example, a light emitting diode that emits infrared light or ultraviolet light may be used. In the case of such a configuration, if a fluorescent substance is applied to the display unit 6 or an optical element for extending or shortening the wavelength of light is provided, the same effect as that of the above-described embodiment can be obtained, The effect of being less likely to be affected by ambient light such as sun rays is exerted.

Although several embodiments of the present invention have been described above,
It is needless to say that the present invention is not limited to such embodiments and can be implemented in various modes without departing from the scope of the present invention.

EFFECTS OF THE INVENTION As described in detail above, the liquid level detection device of the present invention detects the inside of the liquid by the optical element having an angle selectivity among the light emitted from the predetermined position inside the container that stores the liquid. It is configured to select either the light that does not pass through and is directly irradiated or the light that passes through the inside of the liquid, changes the traveling direction, and guides the light to the outer peripheral portion of the container for scattering. Therefore, it is possible to achieve the excellent effect that both the miniaturization of the device and the improved visibility of the liquid level display can be achieved.

This means that, for example, in an environment where it is not possible to secure a sufficient mounting space for the liquid level detection device, such as a fuel tank of a motorcycle or a kerosene tank of an oil stove, and it is relatively difficult to visually confirm the liquid level display, For example, when it is applied to a liquid storage container used at night, in a dark room, etc., a particularly remarkable effect is exhibited.

Further, since the device has a built-in light source, it is possible to accurately detect the liquid surface position without using a night-vision device or the like even in an environment in which the brightness required for liquid surface detection cannot be ensured.

Further, since the light is scattered by the diffusing member, the observable range is expanded, so that a measurement error due to the difference in the viewpoint of the observer does not occur. Therefore, the liquid level position can be measured accurately at any angle.

In addition, if the light source, the optical element, and the display unit are arranged in a predetermined positional relationship, the liquid surface can be detected without fail, so that the display unit can be arranged at the position where it is most observable in the container. Is improved.

Furthermore, the simple structure consisting of the light source, the optical element, and the display section is sufficient, and since there are no positioning parts or mechanically movable parts that require fine adjustment, the reliability and durability of the device are improved and the number of parts is reduced. As a result, the number of assembly steps of the device can be reduced.

Further, as long as it is a container that stores a liquid that refracts the light emitted from the light source, it can be applied to all of the properties of the liquid, for example, regardless of the presence or absence of coloring, thus increasing the versatility of the device. .

[Brief description of drawings]

FIG. 1 is a schematic configuration diagram showing an embodiment of the present invention, FIG. 2 is a hologram making layout diagram thereof, and FIG. 3 is a schematic configuration diagram showing another embodiment. 1 ... Liquid level detector, 4 ... Light emitting part, 5 ... Hologram dry plate, 6 ... Display part, 11 ... Light emitting diode, 13 ... Glass plate, 14 ... Emulsion, 17 ... Ground glass plate

Claims (1)

(57) [Claims] 1. A liquid level detecting device for detecting a liquid level of a liquid stored in a container, wherein the liquid level detecting device is disposed inside the container in a direction intersecting with the liquid level.
An optical element that changes the traveling direction of light directly irradiated from a predetermined light emitting position to a predetermined predetermined direction, a light source that is disposed at the light emitting position and illuminates the inside of the container, and the outer periphery of the container And a diffusing member which is disposed in the predetermined direction of the section and which receives and scatters the light whose traveling direction is changed by the optical element, and a liquid level detecting device.