JPS6212282Y2 - - Google Patents

Description

[Detailed description of the invention] The present invention relates to a scattering floodlight.
The present invention relates to a scattering projector that is most suitable for configuring the irradiation window of a device that measures the characteristics of a sheet-like object.

As a device to measure the characteristics of sheet-like objects,
There is a high-volume scattering/transmission type moisture meter that continuously measures the moisture contained or adsorbed in papermaking (Japanese Patent Application No. 63362/1982).

FIG. 1 is an explanatory diagram of the structure of the moisture meter. In FIG. 1, the upper head 1 has irradiation windows 4 and 5.
, a scattering surface 17 coated with a reflective material, and two through holes are provided in the disk-shaped plate surface, with a reference light filter 14 in one hole and a measurement light filter 15 in the other hole.
It has a rotary sector 13 which is embedded and supported and continuously rotates at a constant speed, and a lamp 7, lenses 8, 9 and a mirror 10 which create parallel rays passing through the irradiation window 4 and parallel rays passing through the irradiation window 5. On the other hand, the lower head 2 has an entrance window 6 and a scattering surface 1 covered with a reflective material.
8, and a lens 1 that converges the light incident on the entrance window 6.
1 and a sensor 12 that detects the converged incident light.

The upper and lower heads 1 and 2 are opposed to each other with a sheet of paper 3 in between, and include a lamp 7, a lens 8, an irradiation window 4, scattering surfaces 17 and 18, an entrance window 6, and a lens 1.
1 and sensor 12 constitute a multiple scattering optical system, and lamp 7, lens 9, mirror 10, irradiation window 5, entrance window 6, lens 11, and sensor 12 constitute a transmission optical system. In the measurement state, the paper 3 is irradiated with intermittent light from the rotating sector 13 from the irradiation windows 4 and 5, and the light that interacts with the paper 3, that is, the measurement light in the multiple scattering optical system.
A time series signal consisting of Mn and reference light Rn, measurement light Mt and reference light Rt in the transmission optical system is detected by sensor 12, and the next stage calculation/control unit (not shown)
The moisture content of the paper is measured by sending it to the paper and performing predetermined calculations.

In such a moisture meter, it has been confirmed through experiments that a more accurate measurement signal can be obtained if the irradiated light from the irradiation window 4 is scattered at the window surface (opening). There is. For this reason, the opening of the irradiation window 4 may be made of a scattering material such as opal glass or opalescent glass. On the other hand, the near-infrared rays that are the irradiation light have the characteristic of being attenuated exponentially depending on the basis weight of the paper 3, and the amount of attenuation can be ignored in a multiple scattering optical system that contacts the paper 3 many times. Therefore, the amount of light from the irradiation window 4 needs to be sufficient.

However, in the moisture analyzer with the above configuration, a part of the light irradiated from the irradiation window 4 hits the paper 3 and the lower head 2.
Since the light is reflected by the scattering surface 18 and enters the irradiation window 4 again, the amount of light in the multiple scattering optical system is reduced by the amount of light that is re-entered.

The present invention has been developed in view of these points, and reduces the decrease in the amount of light at the light projection aperture.
Another object of the present invention is to provide a scattering projector in which the light transmission hole is a substantially horn-shaped reflecting surface in order to emit scattered light.

That is, the scattering projector according to the present invention has a light source, a means for converting the light from the light source into parallel light beams, and a substantially horn-shaped reflecting surface, and the light beam is directed from the large aperture of the horn to the small aperture. It consists of a member that introduces light rays.

Hereinafter, the present invention will be explained with reference to the drawings.

FIG. 2 is an explanatory diagram of the configuration of a scattering projector according to an embodiment of the present invention, and shows an example in which the irradiation window 4 of the moisture meter is configured with a scattering projector. Therefore, in FIG. 2, the same reference numerals as those in FIG. 1 have the same meanings, and therefore the description thereof will be omitted here. Reference numeral 21 denotes a cylindrical member having a light transmitting hole 24 which is a through hole having a horn shape in the axial direction and forming a conical reflective surface with hypotenuses 22 and 23 being straight lines in a longitudinal section. The scattering projector is configured to introduce parallel light rays 31 from the large opening 25 of the cylindrical member 21 toward the small opening 26, and to project the light toward the paper 3 from the small opening 26.

In such a scattering projector, the large opening 25
As shown in Fig. 2, parallel light 31 introduced from the cylindrical member 21 is reflected multiple times by the reflecting surfaces 22 and 23 and projected from the small opening 26, and the amount and direction of the light becomes scattered light as shown in Fig. 3. Fig. 3 is a plot of the results of measuring the light projected from the small opening 26 of the cylindrical member 21 with a goniometer.
In addition, when the scattering projector is used in the gap of the moisture meter, as shown in FIG. 2, if there is reflected light 31' that is reflected by the paper 3 and directed toward the irradiation window 4, since the proportion of the small opening 26 in the irradiation window 4 is small, the light 31' is not re-entered from the small opening 26 into the irradiation window 4, but is reflected by the end surface 27 of the member and directed toward the paper 3 again.
Therefore, there is almost no reduction in the amount of scattered light at the irradiation window 4.

FIG. 4 is an explanatory diagram of the configuration of a scattering projector according to another embodiment of the present invention. The feature of this embodiment is that it has a cylindrical member 21 which forms a horn-shaped light transmission hole 24' whose hypotenuses 22' and 23' in the longitudinal section of the shaft are quadratic curves.

The above horn shape will be explained in detail with reference to FIG. 5. Figure 5 shows equations (1) and (2) in x-y
This is shown on the coordinates.

y=ax ² +bx+c (1) y=ax ² −bx+c (2) However, a, b, c...constants, that is, graphi, b, and c satisfy (2, 0) and (13, 54) It is based on formula (1), and
Graphi was obtained with a=0.1, grapho with b=0.2, and grapha with a=0.3. Also, graphi', b' and c' are (-2,0) and (-13,
54), which is based on equation (2), where graphi' is a=0.1, graphi' is a=0.2, graphi' is
was obtained with a=0.3.

The transmitted light 24' forms a reflective surface in which the oblique sides 22' and 23' of the vertical cross section exhibit quadratic curves of graphs 1 and 1, 2 and 2, or 2 and 3, as shown in FIG. In such a light transmission hole 24', the parallel light ray 31 introduced from the large opening 24' is
As shown in the figure (a part of the parallel light rays is shown in Figure 4), the light is reflected from the wall of the light transmission hole 24' (hypotenuses 22' and 23') and exits from the small opening 26 in the 2π direction. is illuminated. Furthermore, even if the same reflected light as the light 31' in FIG. 2 is present in the gap of the moisture meter using the scattering projector of the light transmission hole 24', it will not re-enter the light through the small opening 26.

As explained in detail above, the scattering projector of the present invention has a substantially horn-shaped light transmission hole, and parallel light rays are introduced from the large aperture of the horn toward the small aperture. Therefore, the scattered light projected in the 2π direction is obtained through the small aperture, and the scattered light hardly enters the light projection aperture again, so that there is no attenuation of the light amount.

[Brief explanation of the drawing]

FIG. 1 is an explanatory diagram of the configuration of a known moisture meter, FIG. 2 is an explanatory diagram of the configuration of a scattering projector according to an embodiment of the present invention, and FIG. 3 is an explanatory diagram of scattered light in the scattering projector of FIG. FIG. 4 is an explanatory diagram of the configuration of a scattering projector according to another embodiment of the present invention, and FIG. 5 is an explanatory diagram of a light transmission hole of the scattering projector of FIG. 4. 1... Upper head, 2... Lower head, 3... Sheet-like paper, 4... Irradiation window of multiple scattering optical system, 5...
...Irradiation window of transmission optical system, 6...Incidence window, 13...
Rotating sector, 21...Cylindrical member, 22, 22',
23, 23'...Octenuse, 24 and 24'...Horn-shaped light transmission hole, 25...Large opening, 26...Small opening.

Claims (1)

[Claims for Utility Model Registration] 1. An upper head and a lower head are disposed facing each other to constitute a multiple scattering type optical system and a transmission type optical system, and a sheet-shaped optical system is provided in the gap formed by the upper and lower heads. An object is passed through the object, and the object is irradiated with measurement light, which is light in a wavelength range that is absorbed by moisture in the object, and reference light, which is light in a wavelength range that is not absorbed, to cause the object to interact with the object. The measurement light and the reference light are detected by a light receiving section common to the two optical systems, and the above-described calculation is performed using a measurement signal and a reference signal outputted from the light receiving section corresponding to the measurement light and the reference light, respectively. A scattering projector that is attached to a device for measuring the amount of water contained in an object, constitutes an irradiation section of the multiple scattering optical system, and irradiates the sheet-like object with the measurement light and the reference light, the scattering projector having a large aperture; A shape in which a light path is formed from the large opening toward the small opening, and incident light in the form of parallel rays entering from the large opening is converted into scattered light and projected from the small opening toward the sheet-like object. A scattering projector characterized by having a reflective surface. 2. The scattering projector according to claim 1, wherein the reflecting surface has a substantially conical shape. 3. The scattering projector according to claim 1, wherein the reflecting surface has a substantially parabolic shape.