JPH07148168A - Optical scanner - Google Patents

Abstract

PURPOSE:To provide a simple and fast switching mechanism for measuring a plurality of wavelengths. CONSTITUTION:A plurality of rays with each different wavelength emitted from a light source falls on the center of rotation of a rotating mirror 10 at each different angle of incidence and by a constant pitch of the angle of incidence. An entrance of each optical fiber 13, composing a group 12 of paths for sending rays, is arranged on the arc 14 of a circle whose center corresponds to the center of rotation of mirror 10. Three rays with three different wavelengths are successively sent to the optical fiber 13 by flickering a plurality of rays with each different wavelength emitted from a light source successively while slightly turning the mirror 10 so as to send a plurality of rays with each different wavelength to the optical fiber 13 successively. The three rays mentioned above are successively sent to the adjacent optical fiber 13 by turning the mirror 10 by one pitch such that rays are sent to the adjacent optical fiber 13.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention irradiates a subject such as a living body with visible or near-infrared measuring light and detects transmitted light or reflected light (including scattered light) to obtain information in the subject. The present invention relates to an optical scanning device for non-destructively obtaining an optical CT such as an optical scanning device for scanning an object with measuring light.

[0002]

2. Description of the Related Art In optical CT, measurement light is emitted from one point around the subject, and light transmitted or reflected inside the subject is received around the subject. Although the irradiation point is moved around the subject, if, for example, light is sequentially transmitted from the n point and is received at the n point, n ² data can be obtained, and thereby the internal tomographic image can be calculated. it can.

One method of optical scanning for obtaining information in the subject is to scan and irradiate the subject with measuring light in one direction from one direction, and the emission position of the measuring light is measured around the subject. There is a way to move it. As another method, there is also a method in which the measurement light is moved in parallel within a range including the subject, and the measurement light is moved around the subject.

However, in these methods, it is necessary to mechanically move the light-transmitting portion for measuring light or the light-receiving portion. In addition, since the light-transmitting end of the light-transmitting unit cannot be moved while it is in contact with the subject, the light-transmitting end is placed at a position away from the subject, and the tomographic image inside the subject can be calculated accurately. Not easy to do.

A plurality of optical scanning devices arranged around the subject are provided as an optical scanning device capable of sequentially irradiating the measuring light from the periphery of the subject by eliminating a mechanically moving portion in the optical scanning mechanism around the subject. A light-transmitting section having a plurality of light-transmitting light guide paths and performing light-transmitting operations from the light-transmitting light guide paths to the subject in a fixed order, and a light-receiving end arranged around the subject. And an optical fiber light receiving portion having

FIG. 1 shows an example of a light transmitting portion and a light receiving portion in a subject of an optical scanning device to which the present invention is applied. Light-transmitting light guide paths I _{1 to} In of the optical fibers of the light-transmitting section are arranged around the subject 2, and one light-receiving end O _{1 to} On is arranged between the light-transmitting light guide paths. The measurement light is sequentially transmitted from the light-transmitting light guide path by light-transmitting pulses, and is received by all the light-receiving ends. The measurement procedure is as follows:
All the light receiving ends O ₁ to On that irradiate the subject 2 with pulsed light from ₁ and transmit the light transmitted through the subject 2 or reflected within the subject 2
At the same time, light is received in parallel to obtain n light receiving signals.

Next, the light transmitting section is advanced by one step, that is, the light pulse is irradiated from the light transmitting light guide path I ₂ to the subject 2,
Light is received by all the light receiving ends O ₁ to On. Repeating this, the light-transmitting light guide paths I _{1 to} In are switched to the n light-transmitting sections n times to obtain a total of n ² light-receiving signals. From this, a tomographic image is obtained by calculation. be able to.

In such an optical measuring device, when observing a certain state of a living body, a multi-wavelength measuring method is also performed in which measuring light of a plurality of wavelengths is irradiated and useful information is obtained from calculation of those measured values. There is. For example, hemoglobin in blood has different wavelength characteristics with respect to absorbance depending on its oxygen saturation, so that the oxygen saturation of hemoglobin indicating the state of a living body can be measured by a multiwavelength measurement method. When such a multi-wavelength measuring method is applied to the optical scanning device as shown in FIG. 1, the measuring light beams of a plurality of wavelengths must be sequentially made incident from the respective light incident ends of the light-transmitting light guides I ₁ to In. I won't.

A method using a rotating mirror is conceivable as a method of switching the measurement light to be incident on the incident ends of the plurality of light-transmitting light guides I _{1 to} In. It is possible to switch the incident position by arranging the incident end of each light guide path on an arc of a circle centered on the rotation center of the rotating mirror and rotating the rotating mirror. In this case, if multi-wavelength measuring light is applied, it is necessary to make measuring light having a plurality of wavelengths enter the rotating mirror from the same optical axis.

FIG. 2 shows a method of placing measuring lights of a plurality of wavelengths on the same optical axis. In FIG. 2 (A), for example, an interference filter 8 for passing light of each wavelength is provided in the optical path of the measuring light 6 from the light source 4 such as a laser device that generates a plurality of light rays of wavelengths λ ₁ , λ ₂ , λ _3. They are arranged so that they can be sequentially inserted into the optical path, the interference filter 8 is switched, and the measurement lights of three wavelengths are successively introduced into the rotating mirror. In FIG. 2B, by inserting the reflection mirror 10 in the optical path or removing the reflective mirror 10 from the optical path, the measuring light beams 6- of multiple wavelengths incident from different directions are generated.
1 to 6-3 are placed on the same optical path.

[0011]

If the measuring lights of a plurality of wavelengths are to be placed on the same optical axis by the method shown in FIG. 2, the filter 8 is switched or the reflection mirror 10 is moved for each wavelength. The wavelength used is 3 because it is necessary.
As the number of wavelengths increases and the number of wavelengths increases, it becomes difficult to adjust the optical axis.
There is a problem that the time for switching wavelengths also becomes long.

According to the present invention, in an optical scanning device in which the incidence of measurement light on a light guide path for light transmission is switched using a rotating mirror, it is possible to perform multiwavelength measurement with a simple mechanism and at high speed. The purpose is.

[0013]

The optical scanning device of the present invention comprises:
In the first aspect, there is provided one rotating mirror, a light source section for directing a plurality of measuring light beams having different wavelengths toward the rotation center of the rotating mirror at different incident angles, and a plurality of light guide paths. The light-transmitting light guide path group in which the part is arranged on an arc of a circle around the rotation center of the rotating mirror and the other end is arranged around the subject, and one end is arranged around the subject. And a light-guiding light guide group,
A first rotation that rotates the rotating mirror so that the plurality of measurement lights are sequentially incident on one light guide path, and a second rotation that rotates the rotating mirror so that the measurement light is incident on the next light guide path. The rotation causes the plurality of measurement lights to scan the subject.

In a second aspect of the optical scanning device of the present invention, one rotating mirror and a plurality of measuring lights having different wavelengths are directed to the rotation center of the rotating mirror, and the incident angles are different from each other and are equal to each other. A light source unit that is incident at a pitch,
It has a plurality of light guide paths, one end of which is arranged at a pitch such that a plurality of measurement lights are incident on adjacent light guide paths one by one on an arc of a circle centered on the rotation center of the rotating mirror, and the other end of which is covered. It is provided with a light-transmitting light guide path group arranged around the sample and a light-receiving light guide path group whose one end is arranged around the sample, and rotates the rotating mirror to scan the sample with measuring light. With
A plurality of measuring lights are switched at each position of the rotating mirror.

[0015]

In the first aspect, a plurality of measurement lights can be sequentially incident on one light guide path of the light-transmitting light guide path group by the first rotation in which the rotary mirror is slightly rotated, and the light source is turned on or off. The measurement light is made to enter by intermittently, and the optical signal from the light receiving light guide path group is detected. Then, the second rotation moves the incident measurement light to the next light guide path. Scanning with a plurality of wavelengths of measurement light is performed by repeating the rotation of the first and second rotating mirrors and blinking or interrupting the light source.

In the second mode, when measuring light beams of three wavelengths are used, for example, the measuring light beams of the first, second and third wavelengths are guided to three adjacent light guide paths at a rotation position of a certain rotating mirror. Each is ready for incidence. Therefore, the measurement light is made incident by sequentially blinking or interrupting the light source such as the first wavelength, the second wavelength, and the third wavelength, and the optical signal from the light receiving light guide path group is detected. Next, by rotating the rotating mirror by one pitch, the measuring light beams of the first, second, and third wavelengths are sequentially shifted by one pitch so that they can enter the three adjacent light guide paths. In this way, the scanning with the measurement light of a plurality of wavelengths is performed by rotating the rotating mirror and blinking or intermittently turning on or off the light source.

[0017]

FIG. 3 shows an embodiment corresponding to the first aspect of the present invention. A plurality of measuring lights having different wavelengths, for example, measuring lights of three wavelengths λ ₁ , λ ₂ , and λ ₃ are incident on the rotating mirror 10 from the light source unit. The measurement lights of the respective wavelengths are directed toward the center of rotation of the rotating mirror 10, have different incident angles from each other, and are incident at the same incident angle pitch. The measurement light of each wavelength may be emitted from different light sources, and the light emitted from one light source is divided into a plurality of wavelengths, which are made incident from different directions. May be.

The light-transmitting light guide path group 12 includes a plurality of optical fibers 1.
3, the light incident end at one end of each optical fiber 13 is arranged on an arc 14 of a circle centered on the rotation center of the rotating mirror 10. The other end of each optical fiber of the light guide path group 12 is fixed by a subject-side fiber ring 16, and the other light emitting end is arranged around the subject 18. A light-receiving optical fiber 20 having one light-receiving end arranged around the subject 18 is fixed to the fiber ring 16, and a light-receiving optical waveguide group including a plurality of optical fibers 20 is guided to a detector. There is.

In this embodiment, the rotating mirror 10 is slightly rotated with respect to one optical fiber 13 so that the measuring lights of three wavelengths can be sequentially incident on the optical fiber 13, while the three wavelengths from the light source are By sequentially blinking or intermittently measuring the measuring light of
Measurement lights of one wavelength are sequentially incident.

Next, the rotary mirror 10 is rotated by one pitch so that the measurement light can enter the next adjacent optical fiber 13. Similarly, the rotary mirror 10 is slightly rotated with respect to the optical fiber 13, and the measuring light beams of three wavelengths from the light source are sequentially blinked or intermittent.
By repeating this, all optical fibers 13 have λ
All the measurement lights of ₁ , λ ₂ and λ ₃ are incident.

FIG. 4 shows an embodiment corresponding to the second aspect of the present invention. Also in FIG. 4, it is assumed that the measuring light beams of three wavelengths λ ₁ , λ ₂ , and λ _{3 having} different wavelengths are incident on the rotating mirror 10 from the light source unit. The measurement lights of the respective wavelengths are directed toward the center of rotation of the rotating mirror 10, have different incident angles from each other, and are incident at the same incident angle pitch. The measurement light of each wavelength may be emitted from different light sources, and the light emitted from one light source is divided into a plurality of wavelengths, which are made incident from different directions. May be. The light-transmitting light guide path group 12 includes a plurality of optical fibers 13, and one end of each of the optical fibers 13 has a light incident end, which is the rotating mirror 1.
On a circular arc 14 centered on the center of rotation of 0, a plurality of measurement lights λ ₁ , λ ₂ , λ ₃ are arranged at a pitch such that they are incident on adjacent optical fibers 13 one by one. The arrangement of the other end of each optical fiber of the light guide path group 12 and the structure of the light receiving optical fiber are the same as those in FIG.

In this embodiment, the rotation of the rotary mirror 10 allows the measurement lights of three wavelengths to enter the three adjacent optical fibers 13. Rotating mirror 1
By sequentially blinking or interrupting the measuring light of three wavelengths from the light source at each rotational position of 0, the measuring light of λ ₁ is incident on the first optical fiber, and then λ ₁ is incident on the second optical fiber. The measurement light of ₂ is incident, and subsequently the measurement light of λ ₃ is incident on the third optical fiber.

Next, the rotating mirror 10 is rotated by one pitch. Similarly, by sequentially switching the three wavelengths, the measurement light of λ ₁ is incident on the _second optical fiber, the measurement light of λ ₂ is incident on the _third optical fiber, and the measurement light of λ ₃ is incident on the fourth optical fiber. To do. In this way, by rotating the rotating mirror 10 by one pitch and blinking or intermittently repeating the measurement light, all the measurement lights of three wavelengths are incident on all the optical fibers 13.

[0024]

According to the present invention, since the wavelength is switched and the incidence on the light guide is switched by one rotating mirror, the measuring time is shortened in the multi-wavelength measurement, and the optical axis adjustment is simplified.

[Brief description of drawings]

FIG. 1 is a schematic cross-sectional view showing an example of a light transmitting unit and a light receiving unit of an optical scanning device which is symmetrical according to the present invention.

2A and 2B are schematic views showing a conventional multi-wavelength switching mechanism.

FIG. 3 is a schematic plan view showing a first embodiment.

FIG. 4 is a schematic plan view showing a main part of the second embodiment.

[Explanation of symbols]

 Reference Signs List 10 rotating mirror 12 light guide path for light transmission 13 optical fiber 14 arc on which the incident end face of the optical fiber for light transmission is arranged 18 object 20 optical fiber of light guide path group for light reception

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Nakamura Kan 1 Nishinokyo Kuwabara-cho, Nakagyo-ku, Kyoto City Kyoto Prefecture Shimadzu Corporation Sanjo Factory

Claims (2)

[Claims] 1. A rotating mirror, a light source section for directing a plurality of measurement light beams having different wavelengths toward the rotation center of the rotating mirror at different incident angles, and a plurality of light guide paths. A group of light-transmitting light guides arranged on an arc of a circle centered on the center of rotation of the rotating mirror, the other end of which is arranged around the subject, and one end of which is configured to receive light which is arranged around the subject. A first rotation for rotating the rotating mirror so that the plurality of measurement lights are sequentially incident on one light guide path of the light transmission light guide group, and the measurement light for the next light guide path. And a second rotation for rotating the rotating mirror so as to move the incidence of the light on the subject to be scanned with the plurality of measurement lights. 2. A rotating mirror, a light source section for directing a plurality of measurement light beams having different wavelengths toward a rotation center of the rotating mirror, the incident angles of which are different from each other, and the light beams are incident at an equal incident angle pitch. And one end portion is arranged at a pitch such that the plurality of measurement light beams are incident on adjacent light guide paths one by one on an arc of a circle having the rotation center of the rotating mirror as a center, and the other end portion of the subject. A group of light-transmitting light guides arranged around, and a group of light-receiving light guides whose one end is arranged around the subject, while rotating the rotating mirror to scan the measurement light on the subject, An optical scanning device characterized in that the plurality of measuring lights are switched at each position of a rotating mirror.