JPH01167637A - Infrared moisture meter - Google Patents

Abstract

PURPOSE:To make efficient measurement with the decreased quantity of the IR rays to be lost from a measuring region by making measurement between a 1st reflecting means having a light condensing characteristic and the 2nd reflecting means which reflects the light condensed by a projecting lens. CONSTITUTION:The light emitted from a convex lens 8 is made into the collimated beams of light which are projected on paper 3. The light transmitted through the paper 3 includes the rectilinear light and the light deflected by scattering which are stopped down by a convex lens 9 and are reflected by a mirror 10 and a detector 11. The reflected light beams return by tracing the same passage again. On the other hand, the light applied to the detector 11 includes the component which is transmitted by the IR ray from an IR source 4 through the paper 3 and is directly entered from the convex lens and the component which is entered after the reflection between the mirrors 7 and 10 and repeated transmission through the paper 3. The ratio of these components is easily changeable by changing the mounting angle phi' of the detector 11.

Description

DETAILED DESCRIPTION OF THE INVENTION <Industrial Application Field> The present invention relates to an infrared moisture meter that measures the moisture content of a sheet-like object using infrared rays.

<Prior art> Fig. 5 shows a conventional example of an infrared moisture meter disclosed in Japanese Patent Publication No. 10773/1983. 1 is a housing for an infrared source, 2 is a housing for an infrared detector, and these are sheet-like objects. They are arranged opposite to each other with a sheet of paper 3 between them, and are fixed in a reciprocating manner in the width direction of the sheet of paper 3. Inside the housing 1 is an infrared source 4.
A mirror-like concave reflector 5 is provided. The infrared source 4 has a white light source lamp 4a, a chopper disk 4b to which a pair of filters are attached, and the concave reflector 5 is the infrared source 4.
The housing 2 has a light tube 51L that projects infrared rays from the housing 2 to the 3. On the other hand, a mirror concave reflector 6 is provided in the housing 2.
A detector 6a is attached to this reflector.

The concave reflectors 5 and 6 form a spherical cavity, and the light tube 5& projects infrared light toward the center 0 of this cavity. The detector 6a is arranged offset by φ with respect to the optical axis of the light tube 5&.

With this configuration, when the open-circuit disc 4b of the infrared 1a source 4 is rotated, a pair of filters on this disc will compare the measurement light that is absorbed by the moisture in the paper 3 and the measurement light that is not absorbed by the moisture. Generates light alternately.

These lights are guided into the cavity through the light tube 5a and project a spot onto the paper 3. The detector 6 & detects both the infrared rays that have passed through the paper 3 and the infrared rays that have been reflected by the concave reflector 5.6 and repeatedly passed through the paper 3. Although not shown in the figure, the measurement light detected by the detector fi 6a The signal and the comparison optical signal are detected separately, and their ratio is calculated and output as a signal representing the moisture content.

In the case of such a device, the infrared rays projected to the center O are scattered by the paper 3, but are reflected by the concave reflectors 5 and 6 and concentrated again at the center O, so that measurements can be carried out efficiently.

Furthermore, by changing the mounting angle φ of the detector 6a, the ratio of the infrared a component that passes through the paper 3 and directly reaches the detector 6a and the infrared component that is reflected by the concave reflector 5.6 and reaches the detector 6a can be changed. can be changed. If the angle φ is made smaller, the former component will increase, and if the angle φ is made larger, the latter component will be increased.

For this reason - in the case of thin paper like tissue vapor,
If the amount of infrared rays absorbed by moisture is small (the detection sensitivity will decrease, but in such a case, the mounting angle of the detector 6a should be increased (so that more infrared components that have repeatedly passed through the paper 3 will be incident) will increase the detection sensitivity. raise.

<Problems to be solved by the invention> However, in such a device, the reflector 6
T! Since it is not one-way, the detector 6a cannot be installed behind the reflector 6 and must be installed on the inner peripheral surface of the reflector 6.
Once the detector 6a is installed in this condition, it is difficult to change the installation angle midway through, and it is not actually possible to change the ratio of the transmitted component and the reflected component of the infrared rays by changing the installation angle. Ta.

The technical problem to be solved by the present invention is that infrared rays from an infrared source can be efficiently used for measurement, and that an infrared component that directly reaches a detector after passing through paper, and an infrared component that repeatedly passes through paper and then detects the The object of the present invention is to realize an infrared moisture meter that can easily change the ratio of the infrared 11 component that reaches the container.

Means for Solving the Problems> The tank structure of the present invention is arranged in the infrared moisture meter between the sheet-like object and the infrared source, and has a hole through which light from the infrared source passes. and a first reflecting means having elemental optical characteristics, a convex lens disposed between the sheet-like object and the infrared detector, and a second reflecting means provided behind the convex lens. The infrared detector is mounted behind the convex lens at a predetermined angle offset from the optical axis so that the infrared rays from the infrared source that have passed through the sheet-like object do not enter the infrared detector, and the infrared detector The component that passes through the sheet-like object and directly reaches the detector is reflected between the first and second reflecting means and the sheet-like object is reflected between the first and second reflecting means. It is possible to change the ratio of the component that reaches the detector after repeatedly passing through the III compound.

Function> The above technical means works as follows. That is, the infrared light passes through the hole of the first reflecting means and is irradiated onto the sheet-like object. The light transmitted through the sheet-like body 5/@ is incident on the convex lens. The detector includes:
an infrared m component that is directly incident after being transmitted through the sheet-like object by the infrared rays from the infrared source; and the first and second infrared components.
An infrared component is provided which is reflected between the reflecting means and incident after repeatedly passing through the sheet-like object. The detector is mounted at a predetermined angle offset from the optical axis so that straight light transmitted through the sheet-like object is not incident, and the mounting angle can be easily changed. .

<Example> The present invention will be described in detail below with reference to the drawings. FIG. 1 is a block diagram showing an apparatus according to an embodiment of the present invention. In FIG. 4, the same elements as those in FIG. 5 are given the same reference numerals, and the explanation thereof will be omitted. First, in housing 1, 7 is paper 3
and the infrared source 4, with a hole 72L in the center through which light from the infrared source 4 passes, as shown in the plan view of FIG.
is provided, and a mirror surface is formed on the surface on the paper 3 side. 8
is a convex lens provided between the mirror 7 and the paper 3, and the optical axis A passes from the infrared source 4 through the hole 78L of the mirror 7 and intersects the paper 3 perpendicularly.
, in the primary housing 2 provided above, 9
is a convex lens provided on the optical axis A1 like the convex lens 8. 10 is a mirror placed behind this convex lens,
It is provided perpendicular to the optical axis A. 11 is a detector provided behind the convex lens 9 like the mirror 10, and is set at an angle φ' with respect to the optical axis A so that the straight light transmitted through the paper 3 by infrared rays from the infrared source 4 does not enter the detector. It is installed offset.

With this configuration, the relationship between the infrared source 4, the mirror 7, and the convex lens 8 is set as shown in FIG. 3, for example. That is, the light from the lamp 4a is condensed by a lens 4c, and the focal point of this lens is W(fl), and the focal point of the convex lens 8 is W(
f2)! The hole 7a of J17 is placed. This hole is formed in the shape of a pinhole to narrow down the light, and the sufficiently narrowed light is emitted toward the lens 8. As a result, the light emitted from the convex lens 8 is converted into parallel light and is irradiated onto the paper 3.The light that has passed through the paper 3 includes straight light that has been scattered and deflected, but these are narrowed down by the convex lens 9. Mirror 10 and detector 11 (
Injected to pH. Most of the emitted light is reflected by the mirror 10 and returns along the same path. On the other hand, the light given to the detector 11 includes an infrared component from the infrared source 4 that passes through the paper 3 and is directly incident from the convex lens 9, and an IJ17.10
The ratio of these components can be easily changed by changing the mounting angle φ'' of the detector 11. For thin paper, the installation angle φ
' is increased and detection sensitivity is increased.

Modified Embodiment> FIG. 4 is a configuration diagram showing another embodiment of the device of the present invention.
In the figure, elements that are the same as those in FIG. 1 are given the same reference numerals, and a description thereof will be omitted.

In this embodiment, instead of a7 and the convex lens 8 in FIG. 1, a Fresnel reflector #i12 having a hole 12a in the center through which light from the infrared source 4 passes is used. In such a case, the number of parts can be reduced compared to the device of the embodiment shown in FIG. 1, and the same effect as this device can be obtained.

Furthermore, instead of this Fresnel reflector, it is also possible to use the concave reflector 5 with a mirrored inner surface in the conventional apparatus shown in FIG.

Further, in the case of the embodiment shown in FIG. 1, the convex lenses 8.9 are arranged so that their optical axes coincide with each other, but they do not necessarily have to be arranged in this way.

Furthermore, although these lenses are arranged so that their optical axes intersect perpendicularly to the paper 3, this need not necessarily be the case; The relationship between Mi7 and the convex lens 8 does not necessarily have to be as shown in FIG.

<Effects of the Invention> According to the present invention, since measurement is performed between the first reflecting means having elemental optical characteristics and the second reflecting means that reflects the light collected by the convex lens, The amount of infrared rays lost from the measurement area is small, allowing efficient measurement.

Further, the detector is provided behind the convex lens and can be easily installed so that the mounting angle can be adjusted.
The mounting angle can be set according to the type of sheet-like object, and measurements can always be made with the same sensitivity.

[Brief explanation of the drawing]

FIG. 1 is a configuration diagram showing an apparatus according to an embodiment of the present invention, FIG. 2 is a plan view of essential parts of the apparatus according to an embodiment of the present invention, FIG. 3 is an explanatory diagram of the operation of the apparatus according to an embodiment of the present invention shown in FIG. 5 is a diagram showing another embodiment of the present invention, and FIG. 5 is a configuration diagram of a conventional device. DESCRIPTION OF SYMBOLS 1... Housing of an infrared source, 2... Housing of an infrared detector, 3... Sheet-shaped object, 4... Infrared source, 4a... Lamp, 4b... Chopper disk, 4
c...lens, 7...mirror, 7a...hole, 8,9.
...Convex lens, 10...Mirror, 11...Detector, 12
...Fresnel reflector, 12a...hole ¥1 Figure 2 Figure 3 Officer 4 Figure 5

Claims (1)

[Claims] In an infrared moisture meter, an infrared ray source and an infrared detector are disposed facing each other while sandwiching a sheet-like object, and the amount of moisture contained in the object is measured by detecting the infrared rays transmitted through the sheet-like object. a first reflecting means disposed between the infrared source and having a hole through which light from the infrared source passes and having light condensing properties, and between the sheet-like object and the infrared detector; and a second reflecting means provided behind the convex lens, and the infrared detector is configured to transmit infrared rays from the infrared source through the sheet-like object behind the convex lens. between the component of the infrared rays from the infrared source that passes through the sheet-like object and directly reaches the detector, and the first and second reflecting means. The infrared moisture meter is configured to be able to change the ratio of the component reflected by the infrared rays and the component that reaches the detector after repeatedly passing through the sheet-like object.