JP5191440B2 - Light transmission system for scanning observation apparatus, confocal observation system, optical coupler, and image creation method - Google Patents

Description

  The present invention relates to a light transmission system, a confocal observation system, and an optical coupler that transmit excitation light irradiated to a subject, receive fluorescence emitted from the subject irradiated with excitation light, and transmit the fluorescence to a light receiving unit in a scanning observation apparatus And an image creation method.

  There is known a confocal microscope apparatus that scans excitation light in an observation target region and receives fluorescence emitted at a point where the excitation light is irradiated instantaneously to form an entire image (see Patent Document 1). ).

  According to the confocal observation, it is possible to obtain a microscopic enlarged observation image in a range of less than 1 mm, for example. However, since the intensity of the fluorescence emitted by the irradiation of the excitation light is low, there is a problem that the SN ratio of the confocal image to be formed is small.

US Pat. No. 5,161,053

  Accordingly, an object of the present invention is to provide an optical transmission system that improves the SN ratio of an image to be created in an optical scanning observation apparatus such as confocal observation that transmits excitation light and fluorescence through a single optical fiber. .

  The light transmission system for a scanning observation apparatus of the present invention is transmitted by a first optical fiber that receives and transmits excitation light from a light source that emits fluorescence when irradiated on a predetermined type of subject, and the first optical fiber. A second optical fiber that transmits excitation light to the observation target region and transmits fluorescence emitted from the observation target region irradiated with the excitation light, and transmits fluorescence transmitted by the second optical fiber to the first light receiving unit. The third optical fiber, the first and third optical fibers and the second optical fiber are optically connected, and the fluorescence transmitted to the second optical fiber is third from the first optical fiber. And an optical coupler for branching the optical fiber.

  The optical coupler preferably branches 75% or more of the fluorescence transmitted to the second optical fiber to the third optical fiber.

  The optical coupler preferably branches 100% of the fluorescence transmitted to the second optical fiber to the third optical fiber.

  In addition, a fourth optical fiber that transmits the pumping light transmitted by the first optical fiber to the second light receiving unit is provided, and the optical coupler is provided between the first and third optical fibers and the fourth optical fiber. It is preferable that the pumping light transmitted to the first optical fiber is more branched to the second optical fiber than the fourth optical fiber.

  The optical coupler preferably branches 75% or more of the pumping light transmitted to the first optical fiber to the second optical fiber.

  The optical coupler preferably branches 100% of the fluorescence transmitted to the first optical fiber to the second optical fiber.

  The confocal observation system of the present invention observes a first optical fiber that receives and transmits excitation light that emits fluorescence when irradiated on a predetermined type of subject, and excitation light transmitted by the first optical fiber. A second optical fiber that transmits the fluorescence emitted from the observation target region irradiated with the excitation light by irradiating the target region, and a third optical fiber that transmits the fluorescence transmitted by the second optical fiber to the first light receiving unit. The optical fiber is optically connected between the first and third optical fibers and the second optical fiber, and the fluorescence transmitted to the second optical fiber is transferred from the first optical fiber to the third optical fiber. It is characterized by comprising an optical coupler that branches many.

  The optical coupler of the present invention receives, from an optical source, excitation light that emits fluorescence when irradiated on a predetermined type of subject, and the excitation light transmitted by the first optical fiber in the observation target region. A second optical fiber that transmits the fluorescence emitted from the observation target region irradiated with the excitation light and a third optical fiber that transmits the fluorescence transmitted by the second optical fiber to the first light receiving unit. The first optical fiber and the third optical fiber branch off more fluorescent light transmitted to the second optical fiber.

  The image creation method of the present invention includes a first optical fiber that receives and transmits excitation light that emits fluorescence when irradiated on a predetermined type of subject from the light source, and the excitation light transmitted by the first optical fiber. A second optical fiber that transmits fluorescence emitted from the observation target region irradiated with excitation light and a third optical fiber that transmits the fluorescence transmitted by the second optical fiber to the first light receiving unit. Between the first optical fiber and the third optical fiber. The first optical fiber branches the first fluorescence to the first optical fiber. An image is created based on the fluorescence transmitted to the light receiving unit.

  According to the present invention, since a larger amount of fluorescence is distributed from the first optical fiber to the third optical fiber, the SN ratio of the fluorescent image is improved.

1 is an external view schematically showing an external appearance of a confocal endoscope apparatus having a light transmission system for a scanning observation apparatus to which an embodiment of the present invention is applied. It is a block diagram which shows roughly the internal structure of a confocal endoscope processor.

Embodiments of the present invention will be described below with reference to the drawings.
FIG. 1 is an external view schematically showing the external appearance of a confocal endoscope apparatus having a light transmission system for a scanning observation apparatus to which an embodiment of the present invention is applied.

  The confocal endoscope apparatus 10 includes a confocal endoscope processor 20, a confocal endoscope 30, and a monitor 11. The confocal endoscope processor 20 is connected to the confocal endoscope 30 and the monitor 11.

  Excitation light for irradiating the observation target area OA is supplied from the confocal endoscope processor 20. The supplied excitation light is transmitted to the tip of the insertion tube 31 of the confocal endoscope 30 and is irradiated toward a point in the observation target region. Fluorescence emitted at one point on the observation target region irradiated with light is transmitted from the distal end of the insertion tube 31 to the confocal endoscope processor 20.

  The emission direction of the excitation light from the insertion tube 31 is changed by an actuator (not shown in FIG. 1) provided at the tip of the insertion tube 31. By changing the emission direction, the irradiated excitation light is scanned over the observation target region. The actuator is controlled by the confocal endoscope processor 20.

  The confocal endoscope processor 20 estimates the emission direction according to the control of the actuator. The confocal endoscope processor 20 receives the fluorescence in the emission direction and generates a pixel signal corresponding to the amount of received light. An image signal of one frame is generated by generating pixel signals for the entire area to be scanned. The generated image signal is transmitted to the monitor 11 and an image corresponding to the image signal is displayed on the monitor 11.

  As shown in FIG. 2, the confocal endoscope processor 20 includes a laser light source 21, a supply fiber 22s (first optical fiber), a connection fiber 22c, and an image receiving fiber 22i (third optical fiber). , A light amount detection fiber 22d (fourth optical fiber), an optical coupler 23, first and second light receiving units 24a and 24b, an excitation light cut filter 25, an image signal processing circuit 26, a scan drive circuit 27, and a system controller 28 etc. are provided.

  When a predetermined type of subject such as a living body is irradiated, excitation light that emits fluorescence is emitted from the laser light source 21. The laser light source 21 is optically connected to the supply fiber 22s, and excitation light emitted from the laser light source 21 enters the supply fiber 22s.

  The supply fiber 22s is optically connected to the connection fiber 22c and the light amount detection fiber 22d by the optical coupler 23, and light can be transmitted between the supply fiber 22s, the connection fiber 22c, and the light amount detection fiber 22d. It is.

  The connection fiber 22c and the light amount detection fiber 22d are optically connected to the image light receiving fiber 22i by the optical coupler 23, and between the image light reception fiber 22i, the connection fiber 22c, and the light amount detection fiber 22d. Can transmit light.

  That is, the optical coupler 23 is a 2 × 2 branching optical coupler and branches the pumping light (wavelength 488 nm) transmitted from the supply fiber 22s into the connection fiber 22c and the light amount detection fiber 22d at a branching ratio of 90:10. Then, a 2 × 2 branching optical coupler is used that branches fluorescence (peak wavelength 515 nm) transmitted from a connecting fiber 22c, which will be described later, to the image receiving fiber 22i and the supplying fiber 22s at a branching ratio of 100: 0. The excitation light transmitted from the connection fiber 22c is also branched into the supply fiber 22s and the image receiving fiber 22i at a branching ratio of 90:10.

  The excitation light that has entered the supply fiber 22s from the laser light source 21 is transmitted to the light quantity detection fiber 22d and the connection fiber 22c.

  The light quantity detection fiber 22d is optically connected to the second light receiving unit 24b. The excitation light transmitted to the light quantity detection fiber 22d is transmitted to the second light receiving unit 24b through the light quantity detection fiber 22d.

  The amount of excitation light is detected by the second light receiving unit 24b. The detected amount of received light is transmitted to the system controller 28. The system controller 28 adjusts the amount of light emitted from the laser light source 21 based on the amount of received light.

  The connection fiber 22c is optically connected to a scanning fiber 32 (second optical fiber) provided in the confocal endoscope 30. The excitation light transmitted to the connection fiber 22c is transmitted to the distal end of the insertion tube 31 by the scanning fiber 32 and emitted from the distal end.

  An actuator 33 is provided at the end of the scanning fiber 32 on the insertion tube 31 side. The actuator 33 displaces the end of the scanning fiber 32 along a predetermined displacement path based on the control of the scan drive circuit 27. By emitting the excitation light while displacing the end of the scanning fiber 32, the excitation light is scanned on the observation target region.

  The scanning fiber 32 is formed of a single mode fiber, and the excitation light is emitted from the core portion on the end surface on the distal end side of the scanning fiber 32, is condensed by a lens unit (not shown), and is minute in the observation target region. Irradiate toward one point. However, due to the diffraction limit, excitation light having an intensity of Gaussian distribution is irradiated around the irradiated central point.

  Fluorescence is emitted by the excitation light in the entire region irradiated with the excitation light. Only reflected light and fluorescence from the minute region at the central point that is confocal with respect to the core portion on the end surface on the distal end side of the scanning fiber 32 are incident on the core portion on the end surface on the distal end side of the scanning fiber 32, and the periphery of the minute region The reflected light and fluorescence of the area are not incident.

  Reflected light and fluorescence of a minute region in the observation target region irradiated with light are transmitted to the optical coupler 23 by the scanning fiber 32. As described above, the reflected light and the fluorescence of the excitation light transmitted by the scanning fiber 32 are branched by the optical coupler 23 into the supply fiber 22s and the image receiving fiber 22i.

  As described above, in the reflected light of the excitation light transmitted by the scanning fiber 32, 90% of the total light amount is branched to the supply optical fiber 22s, and 10% of the total light amount is branched to the image receiving fiber 22i. The Further, as described above, 100% of the total amount of the fluorescence transmitted by the scanning fiber 32 is branched to the image receiving fiber 22i.

  Therefore, the total amount of fluorescence and 10% excitation light transmitted by the scanning fiber 32 are branched to the image receiving fiber 22i. The image receiving fiber 22i is optically connected to the first light receiving unit 24a. An excitation light cut filter 25 is provided between the image light receiving fiber 22i and the first light receiving unit 24a.

  The excitation light emitted from the image receiving fiber 22i is attenuated by the excitation light cut filter 25, and is prevented from entering the first light receiving unit 24a. The fluorescence emitted from the image receiving fiber 22i passes through the excitation light cut filter 25 and enters the first light receiving unit 24a.

  The first light receiving unit 24a generates a pixel signal corresponding to the amount of fluorescence in the minute region irradiated with the excitation light. The pixel signal is transmitted to the image signal processing circuit 26. In the image signal processing circuit 26, the pixel signal is stored in an image memory (not shown). When the pixel signal corresponding to the entire observation target region is stored, the image signal processing circuit 26 performs predetermined signal processing on the pixel signal and transmits it to the monitor 11 as an image signal of one frame.

  As described above, according to the light transmission system for the scanning observation apparatus of the present embodiment, the fluorescence signal transmitted to the scanning fiber 32 is branched more than the laser light source 21 to the first light receiving unit 24a, thereby obtaining the pixel signal. The amount of fluorescent light for generation is increased. Therefore, the SN ratio of the fluorescent image is improved.

  Further, according to the light transmission system for a scanning observation apparatus of the present embodiment, the fluorescence transmitted to the scanning fiber 32 is branched more from the laser light source 21 side to the first light receiving unit 24a side. The amount of incident fluorescence is reduced. Since the amount of fluorescence incident on the laser light source 21 that hinders the stable operation of the laser light source 21 is reduced, the operation of the laser light source 21 is stabilized.

  Further, according to the light transmission system for a scanning observation apparatus of the present embodiment, the first light reception is performed by branching the excitation light transmitted to the connection fiber 22c less than the supply fiber 22s to the image light reception fiber 22i. It is possible to reduce the excitation light incident on the unit 24a.

  As described above, the excitation light emitted from the image receiving fiber 22 i is attenuated by the excitation light cut filter 25. However, since the amount of fluorescent light is generally lower than that of attenuated excitation light, the dynamic range of the created fluorescent image is not sufficiently large. Therefore, the dynamic range of the fluorescence image is improved by reducing the excitation light incident on the first light receiving unit 24a as in the present embodiment.

  In the optical transmission system for a scanning observation apparatus according to this embodiment, the optical coupler 23 branches the fluorescence transmitted through the connection fiber 22c into the image receiving fiber 22i and the supply fiber 22s at a branching ratio of 100: 0. Although it is a structure, what is necessary is just a structure which branches more fluorescence to the image receiving fiber 22i from the supply fiber 22s at least.

  However, it is preferable that more fluorescence is branched into the image receiving fiber 22i, and the fluorescence is branched into the image receiving fiber 22i with a branching rate exceeding 75%, and further with a branching rate of 100% as in this embodiment. It is preferred that

  In the optical transmission system for the scanning observation apparatus of the present embodiment, the optical coupler 23 transmits the excitation light component transmitted by the connection fiber 22c to the image receiving fiber 22i and the supply fiber 22s with a branching ratio of 10:90. Although the configuration is such that the excitation light is branched at least from the image receiving fiber 22i to the supply fiber 22s, any configuration may be used.

  However, it is preferable that more pumping light is branched into the supply fiber 22s, and it is preferable that the pumping light component is branched into the supply fiber 22s with a branching rate exceeding 75%, and further with a branching rate of 100%. .

  However, in the 2 × 2 branching optical coupler, when the pumping light component transmitted by the connecting fiber 22c is branched to the supplying fiber 22s at a branching rate of 100%, the pumping light transmitted by the supplying fiber 22s is used for light quantity detection. It is not branched to the fiber 22i, and adjustment of the emitted light quantity of the excitation light becomes impossible. Therefore, in this embodiment, the excitation light component transmitted by the connection fiber 22c is branched to the image receiving fiber 22i and the supply fiber 22s at a branching ratio of 10:90.

  In the optical transmission system for a scanning observation apparatus according to this embodiment, a 2 × 2 branch optical coupler is used, but a 1 × 2 branch optical fiber may be used. If the connection fiber 22c, the supply fiber 22s, and the image receiving fiber 22i are optically connected, it is possible to improve the SN ratio of the fluorescent image and improve the dynamic range.

  Further, the light transmission system for a scanning observation apparatus according to the present embodiment is configured to be applied to a confocal endoscope apparatus, but the same effect as that of the present embodiment can be obtained even when used for any other scanning observation apparatus. It is possible to obtain. For example, the present invention may be applied to a multiphoton excitation fluorescence microscope apparatus or a second harmonic microscope apparatus.

DESCRIPTION OF SYMBOLS 10 Confocal endoscope apparatus 20 Confocal endoscope processor 21 Laser light source 22s, 22c, 22i, 22d Supply fiber, Connecting fiber, Image receiving fiber, Light quantity detection fiber 23 Optical coupler 24a, 24b First, Second light receiving unit 25 Excitation light cut filter 30 Confocal endoscope 32 Scanning fiber

Claims (8)

A first optical fiber that receives and transmits excitation light from a light source that emits fluorescence when illuminated on a predetermined type of subject;
Irradiating the observation target region with the excitation light transmitted by the first optical fiber, and transmitting the fluorescence emitted from the observation target region irradiated with the excitation light; and
A third optical fiber for transmitting the fluorescence transmitted by the second optical fiber to a first light receiving unit provided with an excitation light cut filter on the incident side ;
The first and third optical fibers and the second optical fiber are optically connected, and the fluorescence transmitted to the second optical fiber is transmitted from the first optical fiber to the third optical fiber. many branches to the optical fiber, and said second optical coupler reflected light of the excitation light in the observation area, which is transmitted to the optical fiber Ru many branches in said than the third optical fiber the first optical fiber It equipped with a door,
The optical coupler branches more than 75% of the fluorescence transmitted to the second optical fiber to the third optical fiber, and the optical coupler further transmits the excitation transmitted to the second optical fiber. An optical transmission system for a scanning observation apparatus , wherein 75% or more of reflected light of light is branched to the first optical fiber .   2. The optical transmission system for a scanning observation apparatus according to claim 1, wherein the optical coupler branches 100% of the fluorescence transmitted to the second optical fiber to the third optical fiber. A fourth optical fiber that transmits the excitation light transmitted by the first optical fiber to a second light receiving unit;
The optical coupler optically connects the first and third optical fibers and the fourth optical fiber, and transmits the pumping light transmitted to the first optical fiber to the fourth light. claim 1 or optical transmission system for scanning observation apparatus according to claim 2, characterized in that to many branches to the second optical fiber from the fiber. The optical transmission for a scanning observation apparatus according to claim 3 , wherein the optical coupler branches 75% or more of the excitation light transmitted to the first optical fiber to the second optical fiber. system. 4. The optical transmission system for a scanning observation apparatus according to claim 3 , wherein the optical coupler branches 100% of the fluorescence transmitted to the first optical fiber to the third optical fiber. 5. A first optical fiber that receives and transmits excitation light from a light source that emits fluorescence when illuminated on a predetermined type of subject;
A second optical fiber that irradiates the observation target region with the excitation light transmitted by the first optical fiber, and transmits the fluorescence emitted from the observation target region irradiated with the excitation light;
A third optical fiber for transmitting the fluorescence transmitted by the second optical fiber to a first light receiving unit provided with an excitation light cut filter on the incident side ;
The first and third optical fibers and the second optical fiber are optically connected, and the fluorescence transmitted to the second optical fiber is transmitted from the first optical fiber to the third optical fiber. many branches to the optical fiber, and said second optical coupler reflected light of the excitation light in the observation area, which is transmitted to the optical fiber Ru many branches in said than the third optical fiber the first optical fiber It equipped with a door,
The optical coupler branches more than 75% of the fluorescence transmitted to the second optical fiber to the third optical fiber, and the optical coupler further transmits the excitation transmitted to the second optical fiber. A confocal observation system , wherein 75% or more of the reflected light of the light is branched to the first optical fiber . A first optical fiber that receives and transmits excitation light that emits fluorescence when irradiated to a predetermined type of subject from the light source, and the excitation light transmitted by the first optical fiber is applied to the observation target region to emit the excitation light. A first optical fiber that transmits the fluorescence emitted from the observation target region irradiated with the first optical fiber, and an excitation light cut filter provided on the incident side of the fluorescence transmitted by the second optical fiber. A third optical fiber that is transmitted to the light receiving unit is optically connected, and the fluorescence transmitted to the second optical fiber is branched more into the third optical fiber than the first optical fiber. is, and the second number is branched into the first optical fiber from the third optical fiber reflected light of the excitation light in the observation area, which is transmitted to the optical fiber, the second optical full 75% or more of the fluorescence transmitted to the optical fiber is branched to the third optical fiber, and the optical coupler further supplies 75% or more of the reflected light of the excitation light transmitted to the second optical fiber. optical coupler, wherein Rukoto is branched to the first optical fiber. An image creation method for creating an image based on the fluorescence branched by the optical coupler according to claim 7 and transmitted by the first optical fiber.

Images