JPH10314174A - Light measurement device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To make the supply of sufficient illumination inside an inspection room and the removal of the influence of disturbance light be compatible. SOLUTION: A filter 17 is stuck to an illumination device 12 and a window 13, the light of the same wavelength area as measuring light is cut and the state of illuminating a testee body 14 or the like is attained. The measuring light is projected to the testee body 14 through an optical fiber 22 for light transmission and the transmitted light is received at one end of the optical fiber 23 for light reception. The light of the wavelength area of visible light transmitted by the optical fiber 23 for the light reception is cut by the filter 24 and only the light of the wavelength area of the measuring light is made incident to a photodetector 25.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a light measuring device for projecting light onto a subject to non-destructively obtain information inside the subject.

[0002]

2. Description of the Related Art By projecting light onto a subject and detecting transmitted / reflected light, information inside the subject can be obtained without destroying the subject. For example, in the medical field, an oxygen monitor for examining the oxidation / reduction state of hemoglobin in blood, an optical CT (computer tomography) device, and the like have been put to practical use or are under research and development. In the light measuring device, it is inevitable that ambient light is mixed into the measuring light. Conventionally, in order to eliminate the influence of this disturbance light, a dark curtain is placed over the transmitting / receiving unit attached to the subject to block the light, or the measurement is performed after putting the subject and the entire optical measurement device in a dark room and turning off the illumination. Alternatively, the transmitting / receiving unit is attached to the subject using a belt, and light is shielded by the belt.

[0003]

However, the use of a blackout curtain or a darkroom has poor visibility and impairs operability. In particular, when the subject is a living body (for example, the head of a human), measurement cannot be performed in a bright and normal state, and the subject becomes sleepy or depressed due to darkness. There is also. In the case of fixing light with a belt and blocking light, it is necessary to tighten the belt, which may cause pain to the subject, and is not applicable to some subjects.

[0004] In view of the above, the present invention makes it possible to perform measurement in a normal brightness without setting a dark state, and eliminate the influence of disturbance light without inconvenience such as tightening a belt. It is an object of the present invention to provide a light measuring device improved as described above.

[0005]

In order to achieve the above object, in a light measuring device according to the present invention, at least an illuminating means for illuminating a measuring object, a measuring light projecting means for projecting measuring light to the measuring object, A light receiving means for receiving light from the measurement target, a light detecting means for guiding the received light, and a light detecting means attached to the illuminating means, substantially blocking the wavelength range of the measurement light and passing the visible light wavelength range. (1) optical filter means, and second optical filter means inserted into the light guide system to the light detection means and substantially passing the wavelength range of the measurement light and blocking the wavelength range of the visible light. Is the feature.

[0006] The first optical filter means attached to the illuminating means for illuminating the object to be measured has characteristics such that the wavelength range of the measurement light is substantially cut off and the wavelength range of the visible light is passed. Therefore, it is possible to irradiate and irradiate the measurement target with visible light while avoiding the reception of disturbance light that falls within the wavelength range of the measurement light. The light received from the object to be measured is guided to the light detecting means via the second optical filter means. The characteristic of the second optical filter means is that the wavelength range of the measuring light is substantially transmitted and visible light is transmitted. The wavelength range is cut off, and only the measuring light is detected by the light detecting means. In other words, while illuminating with the visible light while preventing the measurement light from being mixed with the light that is confusing to the measurement, only the measurement light is detected while excluding the visible light.
As in the case where the camera is placed in a dark room, it is possible to achieve both the removal of disturbance light and the usual illumination.

The characteristic of the first optical filter means that the wavelength range of the measurement light is substantially cut off and the wavelength range of the visible light is passed is that the wavelength range of the measurement light is the wavelength range of the visible light. It can be realized not only when they are on the long wavelength side or short wavelength side but they do not overlap, but also when the wavelength range of the measurement light and the visible light wavelength range overlap.In the latter case, It may be one that passes only a part of the wavelength range of the visible light that does not overlap with the wavelength range of the measurement light, and includes such characteristics. The same applies to the characteristics of the second optical filter means. When the wavelength range of the measurement light and the wavelength range of the visible light overlap, the wavelength range of the visible light is not substantially transmitted, but The part overlapping the wavelength range will pass through.

[0008]

Next, embodiments of the present invention will be described in detail with reference to the drawings. In FIG. 1, an inspection room 11 is provided with an illuminator 12 such as an incandescent lamp or a fluorescent lamp on a ceiling, and a window 13 on a wall.
In the examination room 11, a bed 15 on which a subject 14 is laid is arranged, and a light measuring device 21 such as an oxygen monitor is arranged. A plurality of optical fibers 22 and 23 extend from the light measuring device 21, and their ends are attached to the subject 14 (head) by a belt 16. An optical filter 17 is attached to an illuminator 12 and a window 13 for illuminating the inside of the inspection room 11.

In the light measuring device 21, a photodetector 25 is coupled to one end of a light-receiving optical fiber 23 via an optical filter 24, as shown by enlarging a part of the inside thereof as a part A. As shown in FIG. 2, this light measuring device 21
A measuring light generator 27 such as a laser diode or an LED (light emitting diode) is provided. The measuring light generated from the measuring light generator 27 is guided to the subject 14 via the light transmitting optical fiber 22, and the measuring light is projected onto the subject. The light transmitted through the optical fiber 14 is made incident on one end of an optical fiber 23 for light reception, guided to a photodetector 25 via the optical fiber 23 and an optical filter 24, and detected by the data detector 26.
And measures significant data. The controller 28 includes a data processing device 26, a measurement light generator 27
Etc. to synchronize the operation timing.

For example, when the measurement light generated from the measurement light generator 27 is in the wavelength range of 750 nm to 840 nm, the characteristics of the optical filter 17 attached to the illuminator 12 and the window 13 are as shown in the spectrum b of FIG. The characteristics of the optical filter 24 placed in front of the photodetector 25 are as shown in the spectrum a of FIG. That is, the characteristic of the optical filter 17 is to cut light in a wavelength range longer than the wavelength range of visible light (400 nm to 700 nm), including the wavelength range of the measurement light. In the case of such a characteristic, light in the wavelength range of visible light is cut through but substantially transmitted.

Therefore, even if the optical filter 17 is attached to the illuminator 12, the window 13, or the like, the inspection room 11 does not become dark with human eyes, and the subject 14 receives And the light measuring device 21 and the like are sufficiently illuminated. Then, of the light from the illuminator 12, the window 13, and the like, the component in the wavelength range of the measurement light is cut by the optical filter 17, and
It does not enter the light receiving optical fiber 23. That is, the light in the wavelength range of the measurement light entering the light receiving optical fiber 23 is only the measurement light, and no disturbance light in this wavelength range enters.

The light transmitted by the light receiving optical fiber 23 becomes a measurement light and a visible light component that has passed through the optical filter 17. This visible light component is cut by the optical filter 24 on the front surface of the photodetector 25. Is done. That is, the characteristic of the optical filter 24 cuts a wavelength range shorter than the wavelength range of the measurement light (a wavelength range shorter than 700 nm) as shown in FIG. All will be cut off.

Light from the illuminator 12, the window 13, and the like reaches the photodetector 25 through the two optical filters 17, 24, and the combined characteristics of the two optical filters 17, 24 are shown in FIG. Almost 0% transmittance as shown in FIG.
Almost everything is attached to the photodetector 2
Do not reach 5. In this example, two optical filters 1
The OD value of the sum of 7, 24 is 2.8 or more,
It is suppressed to 10 minus 2.8 power.

Therefore, only the measurement light is incident on the photodetector 25, and the measurement can be performed without being affected by disturbance light. In addition, since the subject 14 and the light measuring device 21 are given sufficient illumination as usual, they do not hinder the work or cause the subject (subject) 14 to be psychologically upset. . The use of the belt 16 can be gradual because the ends of the optical fibers 22 and 23 are simply fixed to the subject 14 and do not block light, and the subject (examinee) 14 is distressed. Not even.

In the above example, the wavelength range (7
50 nm to 840 nm) in the visible light wavelength range (400 nm).
７００700 nm), which can be separated in terms of wavelength. However, even if they are overlapped in terms of wavelength, if there is a portion that does not overlap in the visible light region, the present invention is applied. Is possible. That is, in such a case, a part of the wavelength range of the visible light is cut by the optical filter 17, but the light in the remaining wavelength range that has not been cut can sufficiently illuminate the room.

Further, it is a matter of course that the wavelength range of the measurement light can be set to the shorter wavelength side of the wavelength range of the visible light. The light measuring device 21 is not limited to the above oxygen monitor,
The configuration is not limited to that shown in FIG. Subject 1
In order to project the light to 4 and obtain information inside the light, it is possible to detect not only transmitted light but also light reflected inside.

[0017]

As described above, according to the light measuring apparatus of the present invention, it is possible to perform accurate measurement by removing the influence of disturbance light while providing sufficient illumination in the inspection room. Therefore, measurement data in a normal state of the subject can be obtained without causing any pain or psychological upset to the subject.

[Brief description of the drawings]

FIG. 1 is a schematic view showing an embodiment of the present invention.

FIG. 2 is an exemplary block diagram showing a signal system of the embodiment;

FIG. 3 is a graph showing characteristics of an optical filter.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 11 Inspection room 12 Illuminator 13 Window 14 Subject 15 Bed 16 Belt 17, 24 Optical filter 21 Optical measuring device 22 Transmitting optical fiber 23 Receiving optical fiber 25 Photodetector 26 Data processing device 27 Measurement light generator 28 Controller

Claims (1)

[Claims] 1. An illumination unit for illuminating at least a measurement target, a measurement light projection unit for projecting measurement light onto the measurement target, a light reception unit for receiving light from the measurement target, and a light detection unit for guiding the received light. And attached to the lighting means,
First optical filter means for substantially blocking the wavelength range of the measurement light and passing the wavelength range of visible light, and substantially passing the wavelength range of the measurement light inserted in the light guide system to the light detection means. A second optical filter means for blocking a wavelength range of visible light;