JPS61209339A - Optical measuring apparatus - Google Patents

Abstract

PURPOSE:To enable optical measurement with high accuracy, by simple constitution such that the operation of a ratio is performed by using a signal containing comparing wavelengths obtained by using a filter for passing two comparing wavelengths together. CONSTITUTION:The titled apparatus is equipped with a filter 51 for passing a measuring wavelength lambda2 and a filter 52 for together passing two comparing wavelengths lambda1, lambda3 of both sides of the measuring wavelength lambda2 and provided with a rotary sector 5 rotated by a motor M. The light of a light source 1 is projected to an object 3 to be measured by a projection lens 2 and the transmitted light or reflected light of said projected light is incident to a detection element 6 through a condensing lens 4 and the rotary sector 5 to be amplified by an amplifier 7 and a first signal e1 corresponding to the component of the measuring wavelength lambda2 and a second signal e2 containing both components of the comparing wavelengths lambda1, lambda3 being the outputs of said amplifier 7 enter sample hold circuits 82, 81 and, subsequently, the operation of a ratio is performed by a divider circuit 10 and the properties of the object 1 to be measured are measured to output a measuring signal eo.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field 1] The present invention relates to an apparatus for optically measuring the properties of an object to be measured.

[Prior Art] Conventionally, devices are known that use light to measure the thickness, moisture content, color tone, etc. of an object to be measured. For example, the properties of the object to be measured, such as moisture content, are measured from the ratio of light in a wavelength band that absorbs moisture to light in a wavelength band that does not absorb moisture.

[Problems to be solved by this invention] However,
If colored substances or other substances are mixed into the object to be measured, the spectral characteristics may be tilted as shown in FIG. For this reason, a method can be considered in which two comparison wavelength bands are provided on both sides of the measurement wavelength and the ratio is calculated using the average of the two components of the comparison wavelength bands.

However, as the number of measurement wavelengths and comparison wavelengths increases, filters and detection elements corresponding to the number of required wavelengths are required, and the number of calculation elements increases, resulting in a problem that becomes complicated and expensive. was there.

In view of the above points, it is an object of the present invention to provide an optical measuring device that simultaneously obtains two components of a comparison wavelength, and has a simplified measurement system and improved accuracy.

[Means for Solving Problems] This invention provides a first signal of a component in the measurement wavelength band of the transmitted light or reflected light from the object to be measured, and a first signal of the component of the transmitted light or reflected light from the object to be measured. This is an optical measuring device that measures the properties of an object to be measured from the ratio of a measurement wavelength band to a second signal containing two components in two comparison wavelength bands on both sides.

[Embodiment] FIG. 1 is a configuration explanatory diagram showing an embodiment of the present invention.

In the figure, 1 is a light source for projecting light, the light from this light source 1 is projected onto the object to be measured 3 by a projecting lens 2, and its transmitted light or reflected light is collected by a condensing lens 4. The detection element 6 is passed through a filter 51 provided on the rotating sector 5 rotated by the motor M, which allows the measurement wavelength λ2 shown in FIG. incident on . The detection signal of this detection element 6 is amplified by an amplifier 7, and a first signal e1 corresponding to the component of the measurement wavelength λ2 in the measurement wavelength band and a second signal e1 containing components of both comparison wavelengths λ1 and λ3 of the comparison wavelength band are generated. The signal e2 is held in the first and second sample and hold circuits 81 and 82 by a synchronizing signal from a synchronizing signal generator 9 provided in the rotating sector 5. Then, Waribeng circuit 10
Take the ratio e1/e2 of the first and second signals el and e2 of the first and second sample-and-hold circuits 81 and 82, and take out the measurement signal @eO of the moisture content and other properties of the object to be measured 3. be able to. The functions of these sample and hold circuits 81 and 82 and the side control circuit 1o may be realized by a calculation means such as a microcomputer or a personal computer including a memory.

That is, the filter 51 as a spectroscopic means for the rotating sector 5 has a transmittance characteristic of a single peak at the wavelength λ2 as shown in FIG. , has a double-beak transmittance characteristic of λ3.

By using this filter 52, a value corresponding to the sum of the components of comparison wavelengths λ1 and λ3 on both sides of the measurement wavelength 22 in FIG. This cancels out the decrease in the wavelength λ3, making it possible to always perform accurate measurements.

FIG. 4 is a configuration explanatory diagram showing another embodiment, in which the light from the light source 1 is projected onto the object to be measured 3 through the optical fiber 11,
The emitted light is again transmitted by the optical fiber 11 and separated by the half mirror 12. The light reflected by the half mirror 12 enters the detection element 61 via the filter 51 that transmits the measurement wavelength λ2, and is transmitted through the half mirror 12. The light enters the detection element 62 via the filter 52 that transmits both comparison wavelengths λ1 and λ3, and is transmitted to the detection element 61 .
The outputs e1 and e2 of 62 are ratioed by the measuring means 13,
A measurement signal eo can be extracted.

FIG. 5 shows another embodiment, in which the light from the object to be measured 3 is separated by a spectroscopic mirror 14 as a spectroscopic means, and the spectroscopic mirror 14 transmits light of both wavelengths λ1 and λ3 to the detection element. Since the light incident on the spectroscopic mirror 62 and reflected by the spectroscopic mirror 14 excludes wavelengths λ1 and λ3, it enters the detection element 61 via the filter 51 that transmits the light with the wavelength λ2. The ratio of the outputs e1 and e2 of these detection elements 61 and 62 is taken by the measuring means 13 to obtain the measured output eO.

FIG. 6 shows another embodiment in which the light from the light source 1 is transmitted to the object to be measured 3 via a rotating sector 5 having a filter 51 that transmits the measurement wavelength λ2 and a filter 52 that transmits the comparison wavelength λ1) λ3. The transmitted light or reflected light is detected by the detection element 6, and the measuring means 13 performs the same ratio calculation as described above to measure the properties of the object to be measured 3.

[Effects of the Invention] As described above, the present invention performs a ratio calculation using a signal containing two comparative wavelengths obtained using a spectroscopic means such as a filter or mirror that passes both comparative wavelengths. This makes it possible to use a simple device and perform highly accurate optical measurements.

[Brief explanation of the drawing]

Figures 1, 2, 3, 4, 5, and 6 are
FIG. 1 is an explanatory diagram showing one embodiment of the present invention. DESCRIPTION OF SYMBOLS 1...-Light source, 2... Light projection lens, 3... Measured object, 4... Condensing lens, 5... Rotating sector,
51.52...filter, 6.61.62...
Detection element, 7... Amplifier, 81.82... Sample hold circuit, 9... Synchronization signal generator, 10.
...Divider, 11...Optical fiber, 12...
Half mirror 113... Measuring means, 14... Spectroscopic mirror Patent applicant Chino Seisakusho Co., Ltd. Year 60

Claims (1)

[Claims] 1. A first signal of a component in the measurement wavelength band of the transmitted light or reflected light from the object to be measured, and a first signal of the component of the measurement wavelength band of the transmitted light or reflected light from the object to be measured. 1. An optical measurement device that measures the properties of an object to be measured based on the ratio between the signal and a second signal that includes two components in two comparative wavelength bands. 2. The optical measurement according to claim 1, wherein the second signal is obtained using a spectroscopic means that transmits both of the two wavelength components of the two comparative wavelength bands. Device.