JP5298602B2 - Oil film detector - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a simply designed reflectivity detecting device capable of coping to the great vertical fluctuation of the height of a detection object plane. <P>SOLUTION: An oil film detecting device E1 includes a laser source 100 emitting a laser beam L1, an irradiating section 200 for irradiating a predetermined area with the laser beam L1 emitted from the laser source 100, a half mirror 310, a coaxial vertical illuminating section 300 for leading a laser beam L3 irradiating a water surface W and a laser beam L4 reflected from the water surface W so that the optical axes of the laser beams L3 and L4 become coaxial, and a light receiving section 400 for receiving a laser beam L5 from the vertical illuminating section 300. The vertical illuminating section 300 has the half mirror 310 reflect the laser beam L2, leads the laser beam L3 so as to regularly be reflected from the water surface W, makes the half mirror 310 transmit the laser beam L4 regularly reflected from the water surface W, and leads the laser beam L5 so as to be received by the light receiving section 400. <P>COPYRIGHT: (C)2010,JPO&amp;INPIT

Description

  The present invention relates to a reflectance detection apparatus that detects reflectance by reflecting detection light on a surface to be detected, for example, reflectance detection used to detect an oil film on a water surface of a water purification plant, a river, a lake, or the like. It relates to the device.

  Focusing on the fact that the reflectance of light by the oil film is higher than the reflectance of light by the water surface, the reflectance is obtained by irradiating the water surface with light and measuring the intensity of the reflected light. An oil film detection method of detecting the presence or absence is known. As an apparatus using this method, for example, an oil film detection apparatus described in Patent Documents 1 to 6 is known. The problem with these oil film detectors is that, in general, even oil films with a small area can be detected over a wide range without being affected by the state of the water surface (water level fluctuations, waves, presence or absence of suspended matter, etc.). is there.

  Specifically, when the irradiation angle of the detection light such as laser light from the fixed light source to the water surface is constant, the distance between the light source and the water surface when the water level fluctuates or ripples occur. And the direction of reflected light changes. Therefore, the reflected light from the water surface is not sufficiently received by the light receiving unit, and the oil film is difficult to detect. As a countermeasure for that, it is conceivable to increase the light receiving area for receiving the reflected light from the water surface by increasing the size of the light receiving unit itself or by increasing the size of the mirror for condensing the light receiving unit. However, such measures are not preferable because the entire oil film detection device cannot be increased in size and requires a large installation area. Conventionally, various techniques have been proposed as alternatives to such measures.

  For example, Patent Literature 1 and Patent Literature 2 disclose an oil film detection device that changes the angle of laser light emitted to a water surface from a light source at a constant cycle by mechanical means. Furthermore, Patent Document 2 also discloses a structure in which the detection means (light source and detection unit) is moved up and down in accordance with fluctuations in the water level to keep the distance between the light source and the water surface constant.

In Patent Document 3, light from a light source is irradiated onto a water surface as a divergent beam by a concave lens, and re-reflected light from the water surface when the reflected light is reflected by a recursive reflector is detected through the concave lens. An oil film detection device provided with the optical system is disclosed.
Patent Document 4 discloses an oil film detector including a rotating mirror that scans laser light from a light source and a plurality of reflecting mirrors arranged around the rotating mirror. In other words, by using these reflecting mirrors to scan the laser beam across the water surface from a plurality of directions, it is stable against undulations in all directions and the angle of the water surface without using a large-diameter parabolic mirror. It enables light reception.

Patent Document 5 discloses an oil film detector that arranges a plurality of light sources in an annular shape, irradiates a laser beam on the water surface, and receives the reflected light to reduce the influence of water surface ripples and suspended matter. Yes.
In Patent Document 6, a vibration type or fixed type mirror that can change the irradiation direction of the laser beam is provided, and reflected light from the water surface through these mirrors is received, so that the influence of the ripples on the water surface and the suspended matter can be reduced. A reduced oil film detector is disclosed.

JP 2001-153800 A JP 2003-149146 A JP 2005-24414 A JP-A-10-90177 JP-A-10-213541 JP 2003-149134 A

  However, the devices disclosed in Patent Documents 3 to 6 are not sufficient for fluctuations in the water level. When the water level fluctuates significantly, the reflected light from the water surface comes off from the light receiving unit. There was a problem that.

  The apparatus disclosed in Patent Document 1 is a so-called “float type”, and employs a floating method in which the detector is floated on the water surface. In such a system, the fluctuation of the entire apparatus (float) cannot follow a moderate wave, and when the flow of the installation place is fast, the apparatus is tilted by being pulled by the mooring point. For this reason, there is a problem that the reflected light from the water surface is detached from the light receiving unit. Further, in order to avoid the above-described problems, it is necessary to make the entire apparatus (float) large and heavy. In that case, there is a problem that a winch is required for pulling up for maintenance.

  Furthermore, the apparatus disclosed in Patent Document 2 has a complicated apparatus configuration because it is necessary to move the detection means up and down by the elevating means so that the distance between the detection means and the water surface becomes constant in conjunction with the water level gauge. The control mechanism is also complicated.

The present invention, with a simple structure, and an object thereof is to provide a compatible oil film detection device even when the water level height varies greatly up and down.

Oil film detection apparatus to which the present invention is applied, by reflecting the detection light to the water surface a oil film detection device that detects an oil film, a light emitting means for emitting a detection light, the detection light emitted by said light emitting means , A first optical system that outputs as parallel light having a predetermined irradiation range, and a partial transmission mirror that reflects part of the incident light and transmits the rest, and that is output by the first optical system a second optical system detecting light which light is reflected by the water surface with reflective or transmissive to toward the water surface at the partially transmitting mirror is configured so as to be directed to the partially transmitting mirror, it is reflected by the water surface said second light receiving means for receiving the transmitted or reflected detection light by the partially transmitting mirror of the optical system, arithmetic means for obtaining the information of the detection light received by the light receiving means for calculating the reflectance of the water surface When, only contains the first optical system, the light emitting means A scanning optical system that scans the detected detection light and a concave mirror that reflects light incident through a predetermined focal point to become parallel light are arranged by arranging a plurality of plane mirrors, and scanned by the scanning optical system. An irradiation optical system that reflects the detection light with the concave mirror and irradiates it as parallel light, and the scanning optical system of the first optical system is configured to be rotatable about a rotation axis, and is configured by the light emitting means. A rotating polygon mirror having a plurality of reflecting surfaces on the peripheral surface for reflecting the emitted detection light, wherein the plurality of reflecting surfaces of the rotating polygon mirror are inclined at a predetermined inclination angle with respect to the rotation axis; The predetermined inclination angles of adjacent reflecting surfaces of the reflecting surfaces of the plurality of reflecting surfaces are different from each other, and when the rotary polygon mirror rotates, a specific reflecting surface of the plurality of reflecting surfaces reflects the detection light. The period from the detection light to the next reflected light In even a short period in which the predetermined inclination angle and repeating the increase and decrease in the rotation direction.

Here, the rotating polygon mirror of the scanning optical system may include the reflecting surface on which the increase or decrease of the predetermined tilt angle along the rotation direction continues .

The oil film detection apparatus to which the present invention is applied is an oil film detection apparatus that detects an oil film by reflecting detection light on a water surface, and includes a light emitting unit that emits detection light, and a detection light emitted by the light emitting unit. Is output as parallel light having a predetermined irradiation range, and a partial transmission mirror that reflects part of the incident light and transmits the rest, and is output by the first optical system. A second optical system configured such that the detection light is reflected or transmitted by the partial transmission mirror and travels toward the water surface, and the detection light reflected by the water surface travels toward the partial transmission mirror; A light receiving means for receiving the detection light transmitted or reflected by the partial transmission mirror of the optical system, and a calculation means for calculating the reflectance of the water surface by obtaining information on the detection light received by the light receiving means. The first optical system includes the light emitting means. A scanning optical system that scans the detection light emitted from the light source and a concave mirror that reflects light incident through a predetermined focal point to become parallel light are arranged by arranging a plurality of plane mirrors, and scanned by the scanning optical system. An irradiating optical system that reflects the detected light by the concave mirror and irradiates it as parallel light, wherein the scanning optical system of the first optical system is configured to be rotatable about a rotation axis, and the light emitting means A rotating polygon mirror having a plurality of reflecting surfaces on its peripheral surface for reflecting the detection light emitted by the plurality of reflecting surfaces, wherein the plurality of reflecting surfaces of the rotating polygon mirror are inclined with different inclination angles with respect to the rotation axis, and , Ru Monodea characterized in that the interval between the scanning lines to which the plurality of reflecting surfaces when the rotary polygon mirror is rotated to scan the water surface reflects the detection light is arranged to vary at random .

According to the present invention, it is possible for water level height is realized with a simple configuration capable of responding oil film detection device even when greatly varies up and down.

Embodiments of the present invention will be described below in detail with reference to the accompanying drawings.
FIG. 1 is a block diagram illustrating a configuration example of an oil film detection device E1 to which the reflectance detection device according to the present embodiment is applied.
The oil film detection device E1 shown in the figure uses the property that the reflectance of light when the oil film is present on the liquid surface is different from the reflectance of light when it is not present on the water surface W that is the detection target surface. It is a device that detects whether or not there is an oil film. The water surface W indicates the water surface of a water purification plant, a river, a lake, or the like, for example, and the position of the water surface W is increased or decreased, and the water surface W is undulated.

This oil film detection device E1 outputs a laser light source 100 as an example of a light emitting unit that emits laser light L1, and a laser light L1 emitted from the laser light source 100 as a parallel light having a predetermined irradiation range. And an irradiation unit 200 as an example of an optical system. More specifically, the irradiation unit 200 outputs a laser beam L2 that irradiates a predetermined irradiation range by scanning the laser beam L1. The laser beam L2 is a so-called laser beam L2 having no or almost no difference in size between the irradiation range (cross-sectional area of the beam group) on the upstream side of the optical path and the irradiation range (cross-sectional area of the beam group) on the downstream side of the optical path. Parallel light.
In the present specification, the term “parallel light” refers to laser light in which the irradiation range (cross-sectional area) of the light formed in the beam group by scanning one laser light is substantially unchanged depending on the position on the optical path. It shall be said.

The oil film detection device E1 also guides the laser beams L3 and L4 so that the optical axis of the laser beam L3 irradiated on the water surface W and the optical axis of the laser beam L4 reflected by the water surface W are coaxial. A coaxial epi-illumination unit 300 as an example, and a light-receiving unit 400 as an example of a light-receiving unit that receives the laser light L5 from the coaxial epi-illumination unit 300. The coaxial epi-illumination unit 300 includes a half mirror 310 as an example of a partial transmission mirror that reflects part of incident light and transmits the remaining part. The half mirror 310 is a plate-like member formed so that the intensity of reflected light and transmitted light is substantially equal.
More specifically, the coaxial epi-illumination unit 300 reflects the laser beam L2 from the irradiation unit 200 to the half mirror 310, guides the reflected laser beam L3 to the water surface W, and reflects the laser beam L3 on the water surface W. The totally reflected laser beam L4 is transmitted through the half mirror 310, and the transmitted laser beam L5 is guided to be received by the light receiving unit 400. The laser beam L4 is reflected from the water surface W at an angle equal to the incident angle of the laser beam L3. That is, the incident angle of the laser beam L3 and the reflection angle of the laser beam L4 are equal to each other.

Thus, the irradiation unit 200 is configured to output detection light used for detecting an oil film on the water surface W as parallel light that irradiates a predetermined range. The coaxial epi-illumination unit 300 is configured to cause the detection light to be totally reflected on the water surface W via the half mirror 310 and to direct the detection light that has been totally reflected to the light receiving unit 400 via the half mirror 310.
For this reason, it is possible to irradiate the detection light over a wide range, and even if the height of the water surface W fluctuates and the distance to the oil film detection device E1 changes, the light reception unit 400 receives the detection light necessary for oil film detection. Even if the water surface W undulates, it is not affected by the detection light necessary for detecting the oil film.

  In addition, the oil film detection device E1 obtains intensity information of the laser beam L5 by converting the laser beam L5 received by the light receiving unit 400 into a predetermined signal, and calculates as an example of a calculation unit that calculates the reflectance of the water surface W. A determination unit 600 as an example of a determination unit that determines whether or not an oil film exists on the water surface W based on a calculation result by the unit 500 and the calculation unit 500, and that an oil film exists on the water surface W by the determination unit 600 A notification unit 700 as an example of a notification unit that notifies the user when the determination is made.

Here, as the laser light source 100, an example configured by a laser diode (not shown) and a drive circuit (not shown) that controls the laser diode so that a predetermined voltage is applied can be considered.
A configuration example of the irradiation unit 200 will be described later.

The configuration of the coaxial epi-illumination unit 300 is as described above.
In addition, an example in which the light receiving unit 400 includes a condensing lens (not shown) for condensing the laser light L5 and a photodiode (not shown) that converts the light into an electric signal corresponding to the intensity of the collected light is considered. It is done.

Further, as the calculation unit 500 and the determination unit 600, a CPU (Central Processing Unit) (not shown) that performs digital calculation processing according to a predetermined operation control program (firmware), a CPU working memory, and the like (not shown) are used. An example of a RAM (Random Access Memory) and a ROM (Read Only Memory) (not shown) that stores processing programs executed by the CPU and various data used in the processing programs can be considered.
Further, the notification unit 700 may be configured with a display screen (not shown) that visually notifies the user, and is configured with a communication interface for notifying a remote user by general-purpose communication means. Examples are possible.

FIG. 2 is a block diagram illustrating a configuration example of another oil film detection device E2 to which the reflectance detection device according to the present embodiment is applied. The basic configuration of the oil film detection device E2 is the same as that of the above-described oil film detection device E1 (see FIG. 1). Therefore, the same components are denoted by the same reference numerals, and the description thereof may be omitted.
The oil film detection apparatus E2 shown in the figure includes a laser light source 100, an irradiation unit 200, a coaxial incident unit 300, a light receiving unit 400, a calculation unit 500, a determination unit 600, and a notification unit 700. The coaxial incident part 300 has a half mirror 310. The configuration of the oil film detection device E2 is the same as that of the oil film detection device E1.

  Here, the configuration in which the oil film detection device E2 is different from the oil film detection device E1 will be specifically described. The coaxial epi-illumination unit 300 included in the oil film detection device E2 transmits the half mirror 310 so as to irradiate the water surface W with the detection light, and reflects off the half mirror 310 so that the detection light is incident on the light receiving unit 400. Is different from the coaxial epi-illumination unit 300 provided in the oil film detection device E1 that irradiates the detection light to the water surface W and transmits the detection light to the light receiving unit 400 through the half mirror 310.

  That is, in the coaxial epi-illumination unit 300 provided in the oil film detection device E2, the laser light L3 that irradiates the water surface W is transmitted through the half mirror 310, and the laser light L5 received by the light receiving unit 400 is reflected by the half mirror 310. Is. In other words, the coaxial epi-illumination unit 300 included in the oil film detection device E2 transmits the laser light L2 from the irradiation unit 200 to the half mirror 310, and guides the laser light L3 that is the transmitted light to be totally reflected on the water surface W. In addition, the laser beam L4 totally reflected by the water surface W is reflected by the half mirror 310, and the reflected laser beam L5 is guided to be received by the light receiving unit 400.

[First Embodiment]
FIG. 3 is a block diagram illustrating a configuration example of the irradiation unit 200 according to the first embodiment. In addition, the irradiation part 200 which concerns on this Embodiment can be applied to the oil film detection apparatus E1, and can also be applied to the oil film detection apparatus E2.
As shown in the figure, the irradiation unit 200 of the present embodiment includes a scanning unit 800 as an example of a scanning optical system that scans the laser light L1 emitted from the laser light source 100 two-dimensionally, and two scanning units 800. A parallel light output unit 900 as an example of an irradiation optical system that changes the direction of laser light (beam group) L8 that is scanned in two dimensions and outputs the laser light L2 as parallel light.

More specifically, the laser beam L1 is scanned two-dimensionally by the scanning unit 800, so that the optical path is sequentially changed so as to be continuously swung. The laser beam L8 having the optical path changed in this way passes through a region wider than the beam diameter of one laser beam L1.
The laser beam L8 is scanned at an angle by the scanning unit 800. That is, the optical path of the laser beam L8 is changed so as to be directed in the direction of diffusion by the scanning unit 800. For this reason, the area of the region through which the laser beam L8 passes increases as it goes downstream in the optical path (the left direction in FIG. 3).

  The optical path of the laser beam L8 traveling while diffusing is further changed by the parallel light output unit 900 so that the area of the passing region does not increase or decrease even if the area of the laser beam L8 travels downstream of the optical path. In this way, the laser light L2 whose optical path is changed by the parallel light output unit 900 and travels in parallel is guided to the above-described coaxial incident part 300 (see FIG. 1 or FIG. 2).

Next, configuration examples of the scanning unit 800 and the parallel light output unit 900 will be described.
FIG. 4 is a diagram illustrating a configuration example of the scanning unit 800. That is, (a) in the figure is a diagram for explaining the configuration of the scanning unit 800, and (b) is a diagram for explaining the pattern P of the laser light L8 scanned by the scanning unit 800.
The scanning unit 800 shown in FIG. 6A employs a so-called rotational tilt mirror, and scans the laser light L1 from the laser light source 100 by combining a plurality of rotational mirrors. More specifically, the scanning unit 800 shown in the figure includes a planar disk mirror (first reflecting mirror) 13A attached to the rotating shaft 12A of the driving source (first driving source) 11A, and a driving source. (Second drive source) A flat disk mirror (second reflecting mirror) 13B attached to the rotating shaft 12B of the 11B and a control unit 14 for controlling the drive of the drive sources 11A and 11B are provided. .

The disk mirror 13A is attached to be inclined with respect to the rotating shaft 12A. The disk mirror 13B is attached to be inclined with respect to the rotating shaft 12B. The inclination angle at which the disk mirror 13A is inclined with respect to the rotation axis 12A is θ _1A , and the inclination angle at which the disk mirror 13B is inclined with respect to the rotation axis 12B is θ _1B .

  The disk mirror 13A is arranged with respect to the laser light source 100 so that the laser light L1 from the laser light source 100 is incident on the disk mirror 13A. Further, the disk mirror 13B is arranged with respect to the disk mirror 13A so that the laser light L1 reflected by the disk mirror 13A enters the disk mirror 13B. For this reason, the laser beam L1 is reflected by the disk mirror 13B after being reflected by the disk mirror 13A. The laser beam L8 reflected by the disk mirror 13B travels to the parallel light output unit 900.

The disk mirror 13A is rotated at a rotational speed n _1A per unit time by the drive source 11A, and the disk mirror 13B is rotated at a rotational speed n _1B per unit time by the drive source 11B. The rotation direction of the disk mirror 13A and the rotation direction of the disk mirror 13B are the same. For this reason, the shape of the laser beam L8 drawn by the scanning unit 800 being scanned with the laser beam L1 is a pattern P including a plurality of circular shapes as shown in FIG.

Here, the relationship between the rotational speed n _1A of the disk mirror 13A and the rotational speed n _1B of the disk mirror 13B will be described. The control unit 14 controls the rotational speed n _1A of the disk mirror 13A and the rotational speed n _1B of the disk mirror 13B. That is, the control unit 14 controls the rotation ratio N between the rotation speed n _1A and the rotation speed n _1B based on a user instruction.
It is conceivable to employ various values for the rotation ratio N between the rotation speed n _1A and the rotation speed n _1B . More specifically, when the rotation ratio N is a positive integer (an integer of 1 or more), the pattern P shown in FIG. 4B does not change. On the other hand, when the rotation ratio N is a number other than a positive integer, the pattern P shown in (b) of the figure rotates around the center position PC. By rotating the pattern P in this way, it becomes possible to irradiate the water surface W (see FIG. 1 or 2), which is the detection target surface, with the laser light L3 evenly.

In addition, the pattern P shown to (b) of the figure has illustrated the example, and may be the pattern P other than this. That is, the pattern P changes depending on the tilt angle θ _1A and the rotational speed n _{1A of} the disk mirror 13A and the tilt angle θ _1B and the rotational speed n _{1B of the} disk mirror 13B. For example, when the inclination angles θ _1A and θ _1B are small, the circle becomes small, and when the inclination angles θ _1A and θ _1B are large, the circle becomes large.

FIG. 5 is a diagram illustrating a configuration example of the parallel light output unit 900.
The parallel light output unit 900 shown in the figure has a configuration employing a so-called offset parabola, and converts the laser light L8 from the scanning unit 800 into parallel light using a parabolic mirror. More specifically, the parallel light output unit 900 shown in the figure includes a reflecting mirror 20 as an example of a concave mirror in which a large number of small plane mirrors 22 are arranged on an inner surface 21a of a parabolic curved surface 21.

  The reflecting mirror 20 has an elliptical shape using only a part of a general paraboloid and has a focal point f. The focus f is laid out so that the scanning center of the laser beam L8 scanned by the scanning unit 800 is located. More specifically, the focal point f exists at an offset position. That is, the focal point f exists at a position other than the optical path of the laser beam L2. Therefore, the laser beam L2 is not blocked by the scanning unit 800 located at the focal point f, and an oil film can be detected over a wide range.

  The laser beam L8 as the beam group is gradually expanded, and the irradiation range on the downstream side of the optical path is larger than the irradiation range on the upstream side of the optical path. However, when reflected by the plane mirror 22 of the reflecting mirror 20, the laser light L2 has no difference in size between the irradiation range on the upstream side of the optical path and the irradiation range on the downstream side of the optical path. Thus, the reflecting mirror 20 acts so that the direction of the laser beam L8 from the scanning unit 800 is parallel so as not to diffuse the laser beam L2.

  In addition, as described above, the reflecting mirror 20 has a plurality of plane mirrors 22 arranged therein. For this reason, the beam diameter of each of the laser beams constituting the laser beam L8 does not change when reflected by the reflecting mirror 22. More specifically, when each of the laser beams constituting the laser beam L8 is reflected by the inner surface 21a of the parabolic curved surface 21, the beam diameter is expanded. When laser light with a different beam diameter is used as detection light, the position of the water surface W (see FIG. 1 or FIG. 2) changes, and the light reception of the light receiving unit 400 is affected. However, in this embodiment, since the laser beam L8 is reflected by the plane mirror 22, the beam diameter does not expand and the beam diameter of the laser beam L2 does not change, so that such influence does not occur.

FIG. 6 is a diagram illustrating another configuration example of the parallel light output unit 900.
The parallel light output unit 900 shown in the figure is different from the configuration shown in FIG. 5 in that the focal point f is not offset. When the focal point f is not offset, the laser beam L2 is blocked by the scanning unit 800 as described above, and the range in which the oil film can be detected is a so-called donut shape. However, even with such a configuration, it is possible to detect an oil film for a predetermined range. Further, such a configuration can be adopted when the focal point f cannot be disposed at the offset position for the purpose of downsizing the apparatus.

[Second Embodiment]
FIG. 7 is a diagram illustrating a configuration example of the scanning unit 800 according to the second embodiment. FIG. 8 is a view for explaining the tilt angle of the polygon mirror 31, (a) to (f) are longitudinal sectional views including the reflecting surfaces 31a to 31f, and (g) is for explaining the laser beam L8. FIG.
The scanning unit 800 shown in FIG. 7 employs a so-called tilted polygon mirror, and scans the laser light L1 from the laser light source 100. More specifically, the scanning unit 800 shown in the figure includes a polygon mirror 31 as an example of a rotary polygon mirror having six reflecting surfaces 31a, 31b, 31c, 31d, 31e, and 31f. The polygon mirror 31 is configured to rotate around the rotation shaft 32. In addition, the scanning unit 800 includes a polygon motor (not shown) that rotationally drives the polygon mirror 31 and a control unit (not shown) that controls the driving of the polygon motor.

  The reflection surfaces 31 a to 31 f of the polygon mirror 31 are formed to be inclined with respect to the rotation shaft 32. That is, the reflection surfaces 31 a to 31 f have different inclination angles with respect to the rotation shaft 32. And the laser beam L1 injects in order of the reflective surfaces 31a, 31b, 31c, 31d, 31e, and 31f. For this reason, the laser beam L1 is incident on the reflecting surfaces 31a, 31b, 31c, 31d, 31e, and 31f of the polygon mirror 31 that is rotationally driven in one direction, and the reflected light is converted into (a) to (f) in FIG. ), Laser beams L8a, L8b, L8c, L8d, L8e, and L8f are obtained.

Here, as shown in (a) ~ (f) of FIG. 8, the reflecting surface 31a is a tilt angle theta _3a, the reflecting surface 31b is a tilt angle theta _3b. The reflection surface 31c has an inclination angle of 0 degree (θ _3c = 0), the reflection surface 31d has an inclination angle θ _3d , the reflection surface 31e has an inclination angle θ _3e , and the reflection surface 31f has an inclination angle θ _3f . .
More specifically, each inclination angle has a relationship of θ _3a <θ _3b <0 (θ _3c ) <θ _3d <θ _3e <θ _3f . Adjacent ones of the reflective surfaces 31a to 31f have different inclination angles. As described above, the reflection surfaces 31a to 31f have different inclination angles, and the polygon mirror 31 is formed so that the inclination angles increase in the scanning order of the reflection surfaces 31a to 31f. For this reason, as shown in FIG. 5G, the laser beam L8 in the order of the laser beams L8a to L8f from the top is guided to the parallel light output unit 900 by the scanning of the polygon mirror 31. The parallel light output unit 900 can employ the configuration shown in the first embodiment.

FIG. 9 is a diagram for explaining the tilt angle in the case of a modification of the polygon mirror 31, (a) to (f) are longitudinal sectional views including the reflecting surfaces 31a to 31f, and (g) is a laser. It is a figure explaining light L8.
As shown in the figure, the reflection surface 31a has an inclination angle of 0 degree (θ _4a = 0), and the reflection surface 31b has an inclination angle θ _4b . The reflection surface 31c has an inclination angle θ _4c , the reflection surface 31d has an inclination angle θ _4d , the reflection surface 31e has an inclination angle θ _4e , and the reflection surface 31f has an inclination angle θ _4f . Each inclination angle has a _{relationship of} θ _4e <θ _4d <0 (θ _4a ) <θ _4b <θ _4c <θ _4f . Thus, in the modified example, the reflecting surfaces 31a to 31f are not scanned in descending order of the inclination angle. In the scanning order of the reflecting surfaces 31a to 31f, the tilt angle does not change in order, but changes at random. In other words, the inclination angles θ _{4a to} θ _4f of the reflecting surfaces 31 a to 31 _f repeat increasing and decreasing along the rotation direction of the polygon mirror 31. For this reason, as shown in FIG. 9G, the laser beams L8a to L8f that are directed to the parallel light output unit 900 by the scanning of the polygon mirror 31 are not arranged from the top in order but scattered. Therefore, according to this modification, it is possible to improve the oil film detection probability on the water surface W (see FIG. 1 or 2) without increasing the rotational speed of the polygon mirror 31.

[Third Embodiment]
FIG. 10 is a diagram illustrating a configuration example of the irradiation unit 200 according to the third embodiment.
As shown in the figure, the irradiation unit 200 of the present embodiment has a configuration employing a so-called donut scanner, and laser light L2 that irradiates a predetermined range by scanning the laser light L1 from the laser light source 100. Is output. More specifically, the irradiation unit 200 shown in the figure has a planar rotary mirror (first rotary mirror) 53A and a rotary shaft arranged so as to rotate about the rotary shaft 52A by driving of the drive source 51A. A mirror (mirror) 54A, and a planar rotary mirror (second rotary mirror) 53B and a rotary mirror 54B arranged to rotate about the rotary shaft 52B by driving of the drive source 51B are provided. . The irradiation unit 200 shown in the figure includes a control unit 55 that controls driving of the drive sources 51A and 51B, and a fixed mirror (fixed mirror) 56 on which the laser light L1 from the laser light source 100 is incident. Yes. After the laser beam L1 is reflected by the fixed mirror 56, the laser beam L1 is reflected in the order of the rotating mirror 53A, the rotating mirror 54A, the rotating mirror 53B, and the rotating mirror 54B, and is output as the laser beam L2.

  The positional relationship between the fixed mirror 56 and the rotating mirror 53A will be described. The fixed mirror 56 is disposed so as to reflect the laser beam L1 and enter the rotating mirror 53A. That is, the fixed mirror 56 and the rotating mirror 53A are arranged so that the laser beam L1 incident on the rotating mirror 53A from the fixed mirror 56 is coaxial with the rotating shaft 52A.

  The rotating mirrors 53A and 54A will be further described. The rotating mirror 53A is attached to the rotating shaft 52A. The rotating mirror 54A is attached to the rotating shaft 52A in a state of being separated from the rotating mirror 53A. For this reason, when the rotating shaft 52A is rotated by the drive source 51A, the rotating mirrors 53A and 54A rotate at the same rotational speed, so that the relative positional relationship does not change and is so-called. The rotating mirror 53A and the rotating mirror 54A are arranged so that the reflecting surface of the rotating mirror 53A and the reflecting surface of the rotating mirror 54A face each other. The light incident on and reflected by the rotating mirror 53A enters the reflecting mirror 54A and is reflected.

Further, the rotating mirrors 53B and 54B will be further described. The rotating mirror 53B is attached to the rotating shaft 52B, and the rotating mirror 54B is attached to the rotating shaft 52B in a state of being separated from the rotating mirror 53B. When the rotary shaft 52B is rotated by the drive source 51B, the rotary mirrors 53B and 54B rotate at the same rotational speed, and the relative positional relationship does not change. The rotating mirror 53B and the rotating mirror 54B are arranged so that the reflecting surface of the rotating mirror 53B and the reflecting surface of the rotating mirror 54B face each other, and the light incident on and reflected by the rotating mirror 53B enters the rotating mirror 54B. Reflect.
The rotating mirror 54B is positioned so that the reflected light L2 reflected by the rotating mirror 54B is parallel to the axial direction of the rotating shaft 52B.

The positional relationship between the rotating mirror 54A and the rotating mirror 53B will be described. The rotating mirror 54A and the rotating mirror 53B are arranged so that the reflected light reflected by the rotating mirror 54A enters the reflecting surface of the rotating mirror 53B.
The positional relationship between the rotary mirror 53A and the rotary mirror 53B will be described. The rotary mirror 53B is disposed away from the rotary mirror 53A with respect to the rotary shafts 52A and 52B. Further, the reflecting surface of the rotating mirror 53A and the reflecting surface of the rotating mirror 53B are disposed to face each other.

  Here, the rotation of the rotating mirrors 53A, 54A, 53B, and 54B controlled by the control unit 55 will be described. The control unit 55 controls the drive sources 51A and 51B so that the rotation speed per unit time of the rotary mirrors 53A and 54A and the rotation speed per unit time of the rotary mirrors 53B and 54B are different from each other. That is, the rotating mirrors 53A and 54A and the rotating mirrors 53B and 54B do not rotate in the same positional relationship when viewed from the axial direction of the rotating shafts 52A and 52B, but rotate so that the positional relationship between them changes.

  In addition to the case where the control unit 55 controls the rotation directions of the rotary mirrors 53A and 54A and the rotary mirrors 53B and 54B to be the same as each other, the control unit 55 may control the directions to be opposite to each other. . When control is performed in such a reverse direction, the detection probability of the oil film on the water surface W can be improved.

FIG. 11 is a diagram for explaining the laser light L2 from the irradiation unit 200 according to the third embodiment. FIG. 11A shows a rotating shaft 53A and rotating mirrors 53A, 54A and rotating mirrors 53B, 54B. The case where it is the same position seeing from the axial direction of 52B is shown in figure, (b) shows the case where the position between both is the most distant. 12A and 12B are diagrams for explaining the laser light L2 output from the irradiation unit 200, FIG. 12A is a perspective view of the laser light L2, and FIG. 12B is a plane for explaining the irradiation range of the laser light L2. FIG.
As shown in FIG. 11A, the laser beam L2a is output from the irradiation unit 200 by the rotary mirrors 53A and 54A and the rotary mirrors 53B and 54B that are at the same position when viewed from the axial direction of the rotary shafts 52A and 52B. The Further, as shown in FIG. 5B, the laser beam L2b is irradiated by the rotating mirrors 53A and 54A and the rotating mirrors 53B and 54B that are opposite to each other when viewed from the axial direction of the rotating shafts 52A and 52B. 200 is output.

In more detail, as shown in (a) of FIG. 12, the laser beam L2a the rotation shaft 52A, as viewed in the axial direction of the 52B, the rotation shaft 52A, and at a distance _{R 5a} from 52B, the laser beam L2b is rotary shaft 52A, are spaced a distance _{R 5b} from 52B. The distance R _5a is larger than the distance R _5b (R _5a > R _5b ). As described above, since the rotation speed per unit time of the rotary mirrors 53A and 54A and the rotation speed per unit time of the rotary mirrors 53B and 54B are different from each other, the laser beam L2 has the position of the laser beam L2a and the laser beam. The laser beam L2 moves around the rotary shafts 52A and 52B because the rotary mirrors 53B and 54B rotate around the rotary shafts 52A and 52B. To do. Therefore, the range (irradiation range) irradiated with the laser beam L2 is a hatched portion shown in FIG. 5B, and has a so-called donut shape centered on the positions of the rotation axes 52A and 52B.

  Thus, in the present embodiment, the fixed mirror 56, the pair of rotating mirrors 53A and 54A, and the pair of rotating mirrors 53B and 54B are provided, and the rotation center of the pair of rotating mirrors 53A and 54A and the pair of rotating mirrors 53B, The laser beam L1 reflected by the fixed mirror 56 is reflected in the order of the rotary mirrors 53A, 54A, 53B, and 54B by being configured so as to coincide with the rotation center of the 54B, and the axial direction of the rotary shafts 52A and 52B Is output in parallel with the laser beam L2.

  In other words, in the present embodiment, the laser beam L1 is incident on the rotating mirror 53A that is inclined with respect to the rotating shaft 52A and rotates about the rotating shaft 52A so as to be substantially coaxial with the rotating shaft 52A. The reflected light reflected by the rotating mirror 53A in the direction away from the rotating shaft 52A is incident on the rotating mirror 54A as the first mirror facing the rotating mirror 53A. Thereafter, the reflected light reflected by the rotary mirror 54A substantially parallel to the axial direction of the rotary shaft 52A is separated from the rotary mirror 53A with respect to the axial direction of the rotary shafts 52A and 52B and is inclined with respect to the rotary shaft 52B. The light enters the rotating mirror 53B that rotates about 52B. Further, the reflected light reflected by the rotating mirror 53B enters the rotating mirror 54B as the second mirror facing the rotating mirror 53B and is reflected in the axial direction of the rotating shaft 52B, thereby outputting the laser light L2. ing.

Here, FIG. 13 is a diagram for explaining a modification of the irradiation unit 200 according to the third embodiment. FIG. 13A shows the rotation axis 52A of the laser beam L2 reflected by the rotating mirrors 53A and 54A. , 52B is illustrated as being the most distant from the axial direction, and (b) is illustrating the approaching closest.
This figure is a figure corresponding to FIG. 11, and the configuration of the modified example becomes clearer by comparing both figures. That is, in the third embodiment shown in FIGS. 10 and 11, the pair of rotating mirrors 53A and 54A are arranged so as to form a so-called C shape, and the pair of rotating mirrors 53B and 54B are They are arranged so as to be parallel to each other.

  On the other hand, in the modification shown in FIG. 13, the pair of rotating mirrors 53A and 54A and the pair of rotating mirrors 53B and 54B are arranged so as to have a square shape. More specifically, the pair of rotating mirrors 53A and 54A and the pair of rotating mirrors 53B and 54B are arranged so as to face in directions opposite to each other (the direction of the letter C is upside down). In addition, after the laser beam L1 is reflected by the fixed mirror 56, the laser beam L1 is reflected in the order of the rotating mirror 53A, the rotating mirror 54A, the rotating mirror 53B, and the rotating mirror 54B, and is output as the laser beams L2a and L2b.

As another modification of the irradiation unit 200, an annular mirror (not shown) having a reflecting surface is provided on the inner surface of the ring extending in the circumferential direction instead of the rotating mirror 54A, and the same applies in place of the rotating mirror 54B. It is also conceivable to provide an annular mirror (not shown).
In the case of such a modification, it is not necessary to rotate an annular mirror (not shown). The laser beam L1 reflected by the rotating mirror 53A is reflected by a reflecting surface of an annular mirror (not shown) instead of the rotating mirror 54A, and the laser beam L1 reflected by the rotating mirror 53B is an annular ring (not shown) instead of the rotating mirror 54B. The light is reflected by the reflecting surface of the mirror and becomes laser light L2.

It is a block diagram which shows the structural example of the oil film detection apparatus to which the reflectance detection apparatus which concerns on this Embodiment is applied. It is a block diagram which shows the structural example of another oil film detection apparatus to which the reflectance detection apparatus which concerns on this Embodiment is applied. It is a block diagram which shows the structural example of the irradiation part which concerns on 1st Embodiment. It is a figure which shows the structural example of a scanning part, (a) is a figure explaining the structure of a scanning part, (b) is a figure explaining the pattern of the laser beam scanned by the scanning part. It is a figure which shows the structural example of a parallel light output part. It is a figure which shows the other structural example of a parallel light output part. It is a figure which shows the structural example of the scanning part which concerns on 2nd Embodiment. It is a figure explaining the inclination angle of a polygon mirror, (a)-(f) is a longitudinal cross-sectional view including a reflective surface, (g) is a figure explaining a laser beam. It is a figure explaining the inclination angle in the case of the modification of a polygon mirror, (a)-(f) is a longitudinal cross-sectional view including a reflective surface, (g) is a figure explaining a laser beam. It is a figure which shows the structural example of the irradiation part which concerns on 3rd Embodiment. It is a figure for demonstrating the laser beam by the irradiation part which concerns on 3rd Embodiment, (a) illustrated the case where a rotating mirror and a rotating mirror are the same positions seeing from the axial direction of a rotating shaft. (B) illustrates the case where the position between them is farthest away. It is a figure for demonstrating the laser beam output from an irradiation part, (a) is a perspective view of a laser beam, (b) is a top view explaining the irradiation range of a laser beam. It is a figure explaining the modification of the irradiation part which concerns on 3rd Embodiment, (a) illustrates the case where a laser beam is furthest away seeing from the axial direction of a rotating shaft, ( b) illustrates the case where it is closest.

Explanation of symbols

11A, 11B, 51A, 51B ... drive source, 12A, 12B, 52A, 52B ... rotating shaft, 13A, 13B ... disk mirror, 14, 55 ... control unit, 20 ... reflector, 21 ... parabolic curved surface, 21a ... inner surface 22 ... plane mirror, 53A, 53B, 54A, 54B ... rotating mirror, 56 ... fixed mirror, 100 ... laser light source, 200 ... irradiating part, 300 ... coaxial incident part, 310 ... half mirror, 400 ... light receiving part, 500 ... calculation Part, 600 ... judgment part, 700 ... notification part, 800 ... scanning part, 900 ... parallel light output part, E1, E2 ... oil film detection device, f ... focus, L1, L2, L2a, L2b, L3, L4, L5 L8, L8a, L8b, L8c, L8d, L8e, L8f ... laser light, P ... pattern, PC ... center _{position, R} 5a, R _{5b ...} distance, W ... water, theta _1A, theta _{1B ...} inclination angle, _{3a, θ 3b, θ 3c,} θ 3d, θ 3e, θ 3f, θ 4a, θ 4b, θ 4c, θ 4d, θ 4e, θ 4f ... tilt angle

Claims (3)

By reflecting the detection light to the water surface a oil film detection device that detects an oil film,
A light emitting means for emitting detection light;
A first optical system that outputs detection light emitted by the light emitting means as parallel light having a predetermined irradiation range;
Water together with a partially transmitting mirror that transmits the remainder reflects a portion of incident light, the first detection light outputted by the optical system is directed to the water surface reflection or transmission to at the partially transmitting mirror A second optical system configured such that the detection light reflected by the surface is directed to the partial transmission mirror;
Light receiving means for reflecting water surface for receiving the transmitted or reflected detection light by the partially transmitting mirror of said second optical system,
Calculating means for calculating the reflectance of the water surface to obtain information on the detection light received by the light receiving means,
Only including said first optical system,
A scanning optical system that scans the detection light emitted by the light emitting means;
A concave mirror that reflects parallel light by reflecting light incident through a predetermined focal point is configured by arranging a plurality of plane mirrors, and the detection light scanned by the scanning optical system is reflected by the concave mirror and irradiated as parallel light. Irradiating optical system,
The scanning optical system of the first optical system includes:
A rotary polygon mirror that is configured to be rotatable around a rotation axis and has a plurality of reflection surfaces on the peripheral surface on which the detection light emitted by the light emitting means is reflected,
The plurality of reflection surfaces of the rotary polygon mirror are inclined with a predetermined inclination angle with respect to the rotation axis, and the predetermined inclination angles between adjacent reflection surfaces of the plurality of reflection surfaces are different from each other, and When the rotary polygon mirror rotates, the predetermined inclination angle rotates at a cycle shorter than the cycle from when the specific reflecting surface of the plurality of reflecting surfaces reflects the detection light to the next reflection of the detection light. An oil film detection device characterized by repeating increase and decrease along a direction . 2. The oil film detection apparatus according to claim 1, wherein the rotary polygon mirror of the scanning optical system includes the reflection surface on which the increase or decrease of the predetermined inclination angle along the rotation direction continues . 3. An oil film detection device for detecting an oil film by reflecting detection light on a water surface,
A light emitting means for emitting detection light;
A first optical system that outputs detection light emitted by the light emitting means as parallel light having a predetermined irradiation range;
A partial transmission mirror that reflects a part of the incident light and transmits the remainder, and the detection light output by the first optical system is reflected or transmitted by the partial transmission mirror toward the water surface and at the water surface; A second optical system configured so that the reflected detection light is directed to the partial transmission mirror;
A light receiving means for receiving detection light reflected by the water surface and transmitted or reflected by the partial transmission mirror of the second optical system;
A calculation means for calculating the reflectance of the water surface by obtaining information of the detection light received by the light receiving means;
The first optical system includes:
A scanning optical system that scans the detection light emitted by the light emitting means;
A concave mirror that reflects parallel light by reflecting light incident through a predetermined focal point is configured by arranging a plurality of plane mirrors, and the detection light scanned by the scanning optical system is reflected by the concave mirror and irradiated as parallel light. Irradiating optical system,
The scanning optical system of the first optical system includes:
A rotary polygon mirror that is configured to be rotatable around a rotation axis and has a plurality of reflection surfaces on the peripheral surface on which the detection light emitted by the light emitting means is reflected,
When the plurality of reflecting surfaces of the rotating polygon mirror are inclined with different inclination angles with respect to the rotation axis, and the rotating polygon mirror rotates, the plurality of reflecting surfaces reflect detection light to the water surface. An oil film detection apparatus, wherein the scanning line interval to be scanned is arranged to change randomly .

Images