Scanning endoscope system

A scanning endoscope system has a light guide portion that guides an illuminating light, a drive portion capable of causing the light guide portion to swing so that an irradiation position of the illuminating light draws a locus corresponding to a predetermined scanning pattern, a light detecting portion that receives a return light of the illuminating light and outputs a signal, a control portion that drives the drive portion to perform scan so that the irradiation position of the illuminating light becomes a locus in a spiral shape, and an image generating portion that generates an image of an object based on a signal outputted from the light detecting portion in a predetermined timing, wherein the control portion further performs control for driving the drive portion so that the irradiation position of the illuminating light circles on a same circumference in the predetermined timing.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a scanning endoscope system, and particularly relates to a scanning endoscope system that scans an object and acquires an image.

2. Description of the Related Art

In endoscopes in a medical field, in order to reduce the burdens on subjects, various techniques are proposed, which are for reducing the diameters of the insertion portions that are inserted into the body cavities of the subjects. As one example of the techniques as above, a scanning endoscope that does not have a solid image pickup device in the portion corresponding to the aforementioned insertion portion, and a system that is configured by including the scanning endoscope are known.

More specifically, the system including the aforementioned scanning endoscope is configured to scan an object in a scanning pattern that is set in advance by swinging the distal end portion of an illuminating fiber that guides an illuminating light that is emitted from the light source portion, receive the return light from the object with light receiving fibers disposed around the illuminating fiber, and generate an image of the object by using the signals obtained by separating the return light that is received by the light receiving fibers into respective color components.

As the system including the configuration as described above, the endoscope apparatus as disclosed in, for example, Japanese Patent Application Laid-Open Publication No. 2010-131112 has been conventionally known.

SUMMARY OF THE INVENTION

A scanning endoscope system of one aspect of the present invention has a light guide portion that guides an illuminating light emitted from a light source, a drive portion capable of causing the light guide portion to swing in such a manner that an irradiation position of the illuminating light that is irradiated to an object via the light guide portion draws a locus corresponding to a predetermined scanning pattern, a light detecting portion that is configured to receive a return light of the illuminating light that is irradiated to the object, generate a signal corresponding to intensity of the return light, and output the signal, a control portion that performs control for driving the drive portion to perform scanning so that the irradiation position of the illuminating light becomes a locus in a spiral shape, and an image generating portion that generates an image of the object based on a signal that is outputted from the light detecting portion in a predetermined timing of timings at which the drive portion is controlled, wherein the control portion further performs control for driving the drive portion so that the irradiation position of the illuminating light circles on a same circumference in the predetermined timing at which the image generating portion generates the image of the object.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

FIG. 1toFIG. 13relate to the embodiment of the present invention.FIG. 1is a diagram showing an essential part of a scanning endoscope system according to the embodiment.

As shown inFIG. 1, for example, a scanning endoscope system1is configured by having a scanning endoscope2that is inserted into a body cavity of a subject, a main body apparatus3that is connected to the scanning endoscope2, and a monitor4that is connected to the main body apparatus3.

The scanning endoscope2is configured by having an insertion portion11that is formed by including an elongated shape and flexibility capable of being inserted into a body cavity of a subject. Note that at a proximal end portion of the insertion portion11, a connector or the like not illustrated for detachably connecting the scanning endoscope2to the main body apparatus3is provided.

An illuminating fiber12including a function as a light guide portion that guides an illuminating light supplied from a light source unit21of the main body apparatus3to an objective optical system14, and light receiving fibers13that receive a return light from an object and guide the return light to a detection unit23of the main body apparatus3are respectively inserted through a portion from the proximal end portion to a distal end portion inside the insertion portion11.

An end portion including a light incident face of the illuminating fiber12is disposed in a multiplexer32provided inside the main body apparatus3. Further, an end portion including a light exit face of the illuminating fiber12is disposed in a state in which the end portion is not fixed by a fixing member or the like, in a vicinity of a light incident face of a lens14aprovided at the distal end portion of the insertion portion11.

An end portion including a light incident face of the light receiving fiber13is fixedly disposed in a surrounding of a light exit face of a lens14b, in a distal end face of the distal end portion of the insertion portion11. Further, an end portion including a light exit face of the light receiving fiber13is disposed in a demultiplexer36provided inside the main body apparatus3.

The objective optical system14is configured by having the lens14aon which the illuminating light from the illuminating fiber12is incident, and the lens14bthat emits the illuminating light passing through the lens14ato an object.

An actuator15that drives based on a drive signal that is outputted from a driver unit22of the main body apparatus3is attached to an intermediate portion of the illuminating fiber12in a distal end portion side of the insertion portion11.

Here, explanation will be made hereinafter with a case in which an XY plane as shown inFIG. 2is set on a surface of an object as a virtual plane that is perpendicular to an insertion axis (or an optical axis of the objective optical system14) that corresponds to an axis in a longitudinal direction of the insertion portion11being cited as an example.FIG. 2is a diagram for explaining one example of the virtual XY plane that is set on the surface of an object.

More specifically a point SA on the XY plane ofFIG. 2shows an intersection point of the insertion axis and a paper surface in a case in which the insertion axis of the insertion portion11is assumed to be present in a direction corresponding to a direction from a front side of the paper surface to a back side and is virtually set. Further, an X axis direction in the XY plane ofFIG. 2is set as a direction toward a right side from a left side of the paper surface. Further, a Y axis direction in the XY plane ofFIG. 2is set as a direction toward an upper side from a lower side of the paper surface. Further, the X axis and the Y axis that configure the XY plane ofFIG. 2intersect each other in the point SA.

The actuator15is configured by having an X axis actuator (not illustrated) that acts so as to swing the end portion including the light exit face of the illuminating fiber12in the X axis direction based on a first drive signal that is outputted from the driver unit22of the main body apparatus3, and a Y axis actuator (not illustrated) that acts to swing the end portion including the light exit face of the illuminating fiber12in the Y axis direction based on a second drive signal that is outputted from the driver unit22of the main body apparatus3. The actuator15can cause the end portion including the light exit face of the illuminating fiber12to swing so that an irradiation position of the illuminating light with which the object is irradiated draws a locus corresponding to a predetermined scanning pattern by actions of the X axis actuator and the Y axis actuator as described above.

Inside the insertion portion11, a memory16is provided, in which endoscope information including various kinds of information such as individual identification information of the scanning endoscope2is stored in advance. The endoscope information that is stored in the memory16is read by a controller25of the main body apparatus3when the scanning endoscope2and the main body apparatus3are connected.

The main body apparatus3is configured by having the light source unit21, the driver unit22, the detection unit23, a memory24and the controller25.

The light source unit21is configured by having a light source31a, a light source31b, a light source31cand the multiplexer32.

The light source31aincludes, for example, a laser light source, and is configured to emit a light of a wavelength band of a red color (hereinafter, also called an R light) to the multiplexer32when the light source31ais turned on by control of the controller25.

The light source31bincludes, for example, a laser light source, and is configured to emit a light of a wavelength band of a green color (hereinafter, also called a G light) to the multiplexer32when the light source31bis turned on by control of the controller25.

The light source31cincludes, for example, a laser light source, and is configured to emit a light of a wavelength band of a blue color (hereinafter, also called a B light) when the light source31cis turned on by control of the controller25.

The multiplexer32is configured to multiplex the R light emitted from the light source31a, the G light emitted from the light source31b, and the B light emitted from the light source31cto be able to supply the multiplexed lights to the light incident face of the illuminating fiber12.

The driver unit22is configured by having a signal generator33, digital-analogue (hereinafter, called D/A) converters34aand34b, and an amplifier35.

The signal generator33is configured to generate a signal of a predetermined waveform as shown inFIG. 3, for example, to output the signal to the D/A converter34a, as the first drive signal that swings the end portion including the light exit face of the illuminating fiber12in the X axis direction based on control of the controller25.FIG. 3is a diagram for explaining one example of the signal waveform of the drive signal that is supplied to the actuator provided in the scanning endoscope.

Further, the signal generator33is configured to generate a signal of a waveform obtained by a phase of the aforementioned first drive signal being shifted by 90° to output the signal to the D/A converter34b, as the second drive signal that swings the end portion including the light exit face of the illuminating fiber12in the Y axis direction based on control of the controller25.

The D/A converter34ais configured to convert the digital first drive signal outputted from the signal generator33into an analogue first drive signal to output the analogue first drive signal to the amplifier35.

The D/A converter34bis configured to convert the digital second drive signal outputted from the signal generator33into an analogue second drive signal to output the analogue second drive signal to the amplifier35.

The amplifier35is configured to amplify the first and the second drive signals that are outputted from the D/A converters34aand34bto output the first and the second drive signals to the actuator15.

Here, an amplitude value (a signal level) of the waveform of the drive signal illustrated inFIG. 3gradually decreases with a time point T1at which the amplitude value becomes a maximum value as a starting point, and gradually increases immediately after the amplitude value becomes zero at a time point T2to be the maximum value at a time point T3. The amplitude value gradually decreases immediately after the amplitude value keeps the maximum value in a time period from the time point T3to a time point T4, and becomes zero at a time point T5.

The first drive signal including the waveform as shown inFIG. 3is supplied to the X axis actuator of the actuator15, and the second drive signal obtained by the phase of the first drive signal being shifted by 90° is supplied to the Y axis actuator of the actuator15. Thereby the end portion including the light exit face of the illuminating fiber12is caused to swing with the point SA as a center. Further, in response to the swing of the illuminating fiber12as above, the locus of the illuminating light with which the surface of the object is irradiated changes in a sequence ofFIG. 4toFIG. 5toFIG. 6toFIG. 4. . . .FIG. 4is a diagram for explaining a locus in a first spiral shape that is drawn when the virtual XY plane as inFIG. 2is scanned.FIG. 5is a diagram for explaining a locus in a second spiral shape that is drawn when the virtual XY plane as inFIG. 2is scanned.FIG. 6is a diagram for explaining a locus in a circular shape that is drawn when the virtual XY plane as inFIG. 2is scanned.

More specifically, in the time point T1corresponding to a scan start timing for an object, a point YMAX that is an outermost point of irradiation coordinates of the illuminating light in the surface of the object is irradiated with the illuminating light. Subsequently, as the amplitude values of the first and the second drive signals decrease from the time point T1to the time point T2, the irradiation coordinates of the illuminating light in the surface of the object displace in such a manner as to draw the locus in the first spiral shape inward with the point YMAX as the starting point, and further, when the time point T2arrives, a position corresponding to a point SA in the surface of the object is irradiated with the illuminating light (seeFIG. 4).

Further, as the amplitude values of the first and the second drive signals increase from the time point T2to the time point T3, the irradiation coordinates of the illuminating light in the surface of the object displace in such a manner as to draw the locus in the second spiral shape outward with the point SA as the starting point. Further, when the time point T3arrives, the point YMAX that is the outermost point of the irradiation coordinates of the illuminating light in the surface of the object is irradiated with the illuminating light (seeFIG. 5).

Thereafter, in a time period from the time point T3until the time point T4, the irradiation coordinates of the illuminating light in the surface of the object displace in such a manner as to circle a predetermined times along a locus in a circular shape with a radius RMAX that corresponds to a distance between the point SA and the point YMAX (seeFIG. 6).

Subsequently, as the amplitude values of the first and the second drive signals decrease from the time point T4to the time point T5, the irradiation coordinates of the illuminating light in the surface of the object displace in such a manner as to draw the locus in the first spiral shape inward with the point YMAX as the starting point. Further, when the time point T5arrives, the point SA in the surface of the object is irradiated with the illuminating light (seeFIG. 4).

The detection unit23is configured by having the demultiplexer36, detectors37a,37band37c, and analogue-digital (hereinafter, called A/D) converters38a,38band38c.

The demultiplexer36includes a dichroic mirror or the like, and is configured to separate the return light emitted from the light exit face of the light receiving fiber13into lights of respective color components of R (red), G (green) and B (blue) to emit the lights to the detectors37a,37band37c.

The detector37ais configured to detect intensity of the R light that is outputted from the demultiplexer36, generate an analogue R signal corresponding to the detected intensity of the R light and output the analogue R signal to the A/D converter38a.

The detector37bis configured to detect intensity of the G light that is outputted from the demultiplexer36, generate an analogue G signal corresponding to the detected intensity of the G light and output the analogue G signal to the A/D converter38b.

The detector37cis configured to detect intensity of the B light that is outputted from the demultiplexer36, generate an analogue B signal corresponding to the detected intensity of the B light and output the analogue B signal to the A/D converter38c.

The A/D converter38ais configured to convert the analogue R signal that is outputted from the detector37ainto a digital R signal and output the digital R signal to the controller25.

The A/D converter38bis configured to convert the analogue G signal that is outputted from the detector37binto a digital G signal and output the digital G signal to the controller25.

The A/D converter38cis configured to convert the analogue B signal that is outputted from the detector37cinto a digital B signal and output the digital B signal to the controller25.

In the memory24, a control program for performing control of the main body apparatus3and the like are stored in advance. Further, in the memory24, the endoscope information that is read by the controller25of the main body apparatus3is stored.

The controller25includes a CPU or the like, and is configured to read the control program stored in the memory24, and perform control of the light source unit21and the driver unit22based on the control program that is read.

The controller25is configured to be able to generate an image based on the respective color signals that are outputted from the detection unit23and cause the monitor4to display the image, while the controller25keeps control for supplying the illuminating light to the illuminating fiber12from the light source unit21, and control for supplying the drive signal to the actuator15from the driver unit22, respectively.

More specifically, the controller25generates an image corresponding to one frame based on the respective color signals outputted from the detection unit23in the time period corresponding to the time period from the time point T1to the time point T2, and an image corresponding to one frame based on the respective color signals outputted from the detection unit23in the time period corresponding to the time period from the time point T2to the time point T3, during the time period from the time point T3until the time point T4and causes the monitor4to display the images, while the controller25keeps control for supplying the illuminating light to the illuminating fiber12from the light source unit21, and control for supplying the drive signal to the actuator15from the driver unit22respectively. Namely, the respective color signals that are outputted from the detection unit23during the time period corresponding to the time period from the time point T3to the time point T4do not contribute to generation of the images.

According to the embodiment described above, an action similar to the action in the time period from the time point T3to the time point T4described above is performed every fixed time period in which scanning for obtaining the image corresponding to two frames is completed. Therefore, according to the embodiment described above, a timing relating to irradiation of the illuminating light to the object, and a timing relating to generation of the image corresponding to the return light from the object can be favorably synchronized without control or the like that temporarily stops at least any one of swing of the illuminating fiber12and supply of the illuminating light to the illuminating fiber12being performed. As a result, according to the embodiment described above, stability of a frame rate at a time of observation using the scanning endoscope can be enhanced as compared with the conventional system.

Note that according to the present embodiment, instead of the drive signal that includes the waveform illustrated inFIG. 3, a drive signal including a waveform as shown inFIG. 7, for example, may be supplied to the actuator15.FIG. 7is a diagram for explaining a first modification of the signal waveform of the drive signal that is supplied to the actuator provided in the scanning endoscope.

Here, an amplitude value (a signal level) of the waveform of the drive signal illustrated inFIG. 7gradually decreases with a time point T11at which the amplitude value becomes a maximum value as a starting point, and gradually increases immediately after the amplitude value becomes zero at a time point T12to be the maximum value at a time point T13. The amplitude value is attenuated to a predetermined value that is less than the maximum value during the time period from a time substantially immediately after the time point T13to a time substantially immediately before a time point T14, is amplified to the maximum value at the time point T14again, and gradually decreases from a time immediately after the time point T14to be zero at a time point T15. Note that the aforementioned predetermined value may be properly set in accordance with, for example, a length of the end portion of the illuminating fiber12that is caused to swing by the actuator15, or the like.

The first drive signal including the waveform as shown inFIG. 7is supplied to the X axis actuator of the actuator15, and the second drive signal that is obtained by the phase of the first drive signal being shifted by 90° is supplied to the Y axis actuator of the actuator15, whereby the end portion including the light exit surface of the illuminating fiber12is caused to swing with the point SA as the center. Further, in response to the swing of the illuminating fiber12as above, the locus of the illuminating light with which the surface of the object is irradiated changes in a sequence ofFIG. 4toFIG. 5toFIG. 8toFIG. 4. . . .FIG. 8is a diagram for explaining an example, which differs fromFIG. 6, of the locus in the circular shape that is drawn when the virtual XY plane as inFIG. 2is scanned.

More specifically, at the time point T11corresponding to the scan start timing for an object, the point YMAX that is the outermost point of the irradiation coordinates of the illuminating light in the surface of the object is irradiated with the illuminating light. Subsequently, as the amplitude values of the first and the second drive signals decrease from the time point T11to the time point T12, the irradiation coordinates of the illuminating light in the surface of the object displace in such a manner as to draw the locus in the first spiral shape inward with the point YMAX as the starting point. Further, when the time point T12arrives, the position corresponding to the point SA on the surface of the object is irradiated with the illuminating light (seeFIG. 4).

Further, as the amplitude values of the first and the second drive signals increase from the time point T12to the time point T13, the irradiation coordinates of the illuminating light in the surface of the object displace in such a manner as to draw the locus in the second spiral shape outward with the point SA as the starting point. Further, when the time point T13arrives, the point YMAX that is the outermost point of the irradiation coordinates of the illuminating light in the surface of the object is irradiated with the illuminating light (seeFIG. 5).

Thereafter, in the time period from the time substantially immediately after the time point T13to the time substantially immediately before the time point T14, the irradiation coordinates of the illuminating light in the surface of the object displace so as to circle predetermined times along a locus in a circular shape with a radius R1 (<RMAX) that corresponds to a distance between the point SA and a point Y1(seeFIG. 8).

Subsequently, as the amplitude values of the first and the second drive signals decrease from the time point T14to the time point T15, the irradiation coordinates of the illuminating light in the surface of the object displace in such a manner as to draw the locus in the first spiral shape inward with the point YMAX as the starting point. Further, when the time point T15arrives, the point SA in the surface of the object is irradiated with the illuminating light (seeFIG. 4).

The controller25generates an image corresponding to one frame based on the respective color signals that are outputted from the detection unit23in a time period corresponding to a time period from the time point T11to the time point T12, and an image corresponding to one frame based on the respective color signals that are outputted from the detection unit23in a time period corresponding to a time period from the time point T12to the time point T13, during a time period from the time point T13until the time point T14and causes the monitor4to display the images, while the controller25keeps control for supplying the illuminating light to the illuminating fiber12from the light source unit21, and control for supplying the drive signal to the actuator15from the driver unit22respectively. Namely, the respective color signals that are outputted from the detection unit23during the time period corresponding to the time period from the time point T13to the time period T14do not contribute to generation of the images.

According to the first modification described above, an action similar to the action in the time period from the time point T13to the time point T14described above is performed every fixed time period in which scanning for obtaining the image corresponding to two frames is completed. Therefore, according to the first modification described above, a timing relating to irradiation of the illuminating light to the object, and a timing relating to generation of the image corresponding to the return light from the object can be favorably synchronized, without control or the like that temporarily stops at least any one of swing of the illuminating fiber12and supply of the illuminating light to the illuminating fiber12being performed. As a result, according to the first modification described above, stability of the frame rate at the time of observation with use of the scanning endoscope can be enhanced as compared with the conventional system.

Note that according to the present embodiment, instead of the drive signal including the waveform illustrated inFIG. 3orFIG. 7, a drive signal including a waveform as shown inFIG. 9, for example, may be supplied to the actuator15.FIG. 9is a diagram for explaining a second modification of the signal waveform of the drive signal that is supplied to the actuator provided in the scanning endoscope.

Here, an amplitude value (a signal level) of the waveform of the drive signal illustrated inFIG. 9gradually decreases until a time point T22with a time point T21at which the amplitude value becomes a maximum value as a starting point, keeps a predetermined value in a time period from the time point T22until a time point T23, and gradually decreases from the time point T23to be zero at a time point T24. The amplitude value gradually increases from a time immediately after the amplitude value becomes zero at the time point T24until a time point T25, keeps a predetermined value in a time period from the time point T25to a time point T26, and gradually increases from the time point T26to be a maximum value at a time point T27. The amplitude value gradually decreases from the time point27until a time point T28, keeps a predetermined value in a time period from the time point T28to a time point T29, and gradually decreases from the time point T29to be zero at a time point T30.

A first drive signal including the waveform as shown inFIG. 9is supplied to the X axis actuator of the actuator15, and a second drive signal obtained by a phase of the first drive signal being shifted by 90° is supplied to the Y axis actuator of the actuator15. Thereby, the end portion including the light exit face of the illuminating fiber12is caused to swing with the point SA as a center. Further, in response to the swing of the illuminating fiber12as above, the irradiation position of the illuminating light that is irradiated along the locus in the spiral shape ofFIG. 4temporarily shifts to a locus in a circular shape illustrated inFIG. 10, and the irradiation position of the illuminating light that is irradiated along the locus in the spiral shape ofFIG. 5temporarily shifts to a locus in a circular shape illustrated inFIG. 11.FIG. 10is a diagram for explaining an example, which differs fromFIG. 6andFIG. 8, of the locus in the circular shape that is drawn when the virtual XY plane as inFIG. 2is scanned.FIG. 11is a diagram for explaining an example, which differs fromFIG. 6,FIG. 8andFIG. 10, of the locus in the circular shape that is drawn when the virtual XY plane as inFIG. 2is scanned.

More specifically, at the time point T21corresponding to a scan start timing for an object, the point YMAX that is the outermost point of the irradiation coordinates of the illuminating light in the surface of the object is irradiated with the illuminating light. Subsequently, as the amplitude values of the first and the second drive signals decrease from the time point T21to the time point T22, the irradiation coordinates of the illuminating light in the surface of the object displace in such a manner as to draw the locus in the first spiral shape inward with the point YMAX as the starting point. Further, when the time point T22arrives, a position corresponding to a point Y2in the surface of the object is irradiated with the illuminating light (seeFIG. 4).

In the time period from the time point T22until the time point T23, the irradiation coordinates of the illuminating light in the surface of the object displace so as to circle predetermined times along a locus in a circular shape with a radius R2 (<RMAX) that corresponds to a distance between the point SA and the point Y2(seeFIG. 10).

Thereafter, as the amplitude values of the first and the second drive signals decrease from the time point T23to the time point T24, the irradiation coordinates of the illuminating light in the surface of the object displace in such a manner as to draw the locus in the first spiral shape inward with the point Y2as the starting point. Further, when the time point T24arrives, the position corresponding to the point SA in the surface of the object is irradiated with the illuminating light (seeFIG. 4).

Further, as the amplitude values of the first and the second drive signals increase from the time period T24to the time period T25, the irradiation coordinates of the illuminating light in the surface of the object displace in such a manner as to draw the locus in the second spiral shape outward with the point SA as the starting point. Further, when the time point T25arrives, a position corresponding to a point Y3in the surface of the object is irradiated with the illuminating light (seeFIG. 5).

In the time period from the time point T25until the time point T26, the irradiation coordinates of the illuminating light in the surface of the object displace so as to circle predetermined times along a locus in a circular shape with a radius R3 (<RMAX) that corresponds to a distance between the point SA and the point Y3(seeFIG. 11).

Thereafter, as the amplitude values of the first and the second drive signals increase from the time point T26to the time point T27, the irradiation coordinates of the illuminating light in the surface of the object displace in such a manner as to draw the locus in the second spiral shape outward with the point Y3as the starting point. Further, when the time point T27arrives, the position corresponding to the point YMAX in the surface of the object is irradiated with the illuminating light (seeFIG. 5).

Subsequently, as the amplitude values of the first and the second drive signals decrease from the time point T27to the time point T28, the irradiation coordinates of the illuminating light in the surface of the object displace in such a manner as to draw the locus in the first spiral shape inward with the point YMAX as the starting point. Further, when the time point T28arrives, the position corresponding to the point Y2in the surface of the object is irradiated with the illuminating light (seeFIG. 4).

In the time period from the time point T28until the time point T29, the irradiation coordinates of the illuminating light in the surface of the object displace so as to circle a predetermined times along the locus in the circular shape with the radius R2 (<RMAX) that corresponds to the distance between the point SA and the point Y2(seeFIG. 10).

Thereafter, as the amplitude values of the first and the second drive signals decrease from the time point T29to the time point T30, the irradiation coordinates of the illuminating light in the surface of the object displace in such a manner as to draw the locus in the first spiral shape inward with the point Y2as the starting point. Further, when the time point T30arrives, the position corresponding to the point SA in the surface of the object is irradiated with the illuminating light (seeFIG. 4).

The controller25generates an image of a first half portion based on the respective color signals, which are outputted from the detection unit23in a time period corresponding to a time period from the time point T21to the time point T22, during a time period from the time point T22until the time point T23, generates an image of a latter half portion based on the respective color signals, which are outputted from the detection unit23in a time period corresponding to a time period from the time point T23to the time point T24, during a time period from the time point T25until the time point T26, and further generates an image corresponding to one frame obtained by the image of the first half portion and the image of the latter half portion being synthesized during the time period from the time point T25until the time point T26to cause the monitor4to display the image corresponding to one frame, while the controller25keeps control for supplying the illuminating light to the illuminating fiber12from the light source unit21, and control for supplying the drive signal to the actuator15from the driver unit22respectively. Namely, the respective color signals that are outputted from the detection unit23during the time period corresponding to the time period from the time point T22to the time point T23, and during the time period from the time point T25until the time point T26do not contribute to generation of the image.

Further, the controller25generates an image of a first half portion based on the respective color signals, which are outputted from the detection unit23in a time period corresponding to a time period from the time point T24to the time point T25, during a time period from the time point T25until the time point T26, generates an image of a latter half portion based on the respective color signals, which are outputted from the detection unit23in a time period corresponding to a time period from the time point T26to the time point T27, during a time period from the time point T28until the time point T29, and further generates an image corresponding to one frame obtained by the image of the first half portion and the image of the latter half portion being synthesized during the time period from the time T28until the time T29to cause the monitor4to display the image corresponding to one frame, while the controller25keeps control for supplying the illuminating light to the illuminating fiber12from the light source unit21, and control for supplying the drive signal to the actuator15from the driver unit22respectively. Namely, the respective color signals that are outputted from the detection unit23during the time period corresponding to the time period from the time point T28to the time point T29do not contribute to generation of the image.

According to the second modification described above, an action similar to any one of the action in the time period from the time point T22to the time point T23, the action in the time period from the time point T25to the time period T26, and the action in the time period from the time point T28to the time point T29is performed every predetermined time period provided in the process of scanning for obtaining the image corresponding to one frame. Therefore, according to the second modification described above, the timing relating to irradiation of the illuminating light to the object, and the timing relating to generation of the image corresponding to the return light from the object can be favorably synchronized without control or the like that temporarily stops at least any one of swing of the illuminating fiber12and supply of the illuminating light to the illuminating fiber12being performed. As a result, according to the second modification described above, stability of the frame rate at the time of observation with use of the scanning endoscope can be enhanced as compared with the conventional system.

Note that according to the present embodiment, instead of the drive signal including the waveform illustrated inFIG. 3,FIG. 7orFIG. 9, a drive signal including a waveform as shown inFIG. 12, for example, may be supplied to the actuator15.FIG. 12is a diagram for explaining a third modification of the signal waveform of the drive signal that is supplied to the actuator provided in the scanning endoscope.

Here, a first drive signal including the waveform as shown inFIG. 12is supplied to the X axis actuator of the actuator15, and a second drive signal that is obtained by a phase of the first drive signal being shifted by 90° is supplied to the Y axis actuator of the actuator15. Thereby, in each of a time period from a time point T41until a time point T42, and a time period from a time point T43until a time point T44, the end portion including the light exit face of the illuminating fiber12is caused to swing in such a manner as to draw a locus in a spiral shape with the point SA as a center, namely, in a sequence of the locus in the second spiral shape as illustrated inFIG. 5to the locus in the first spiral shape as illustrated inFIG. 4.

Note that according to the waveform of the drive signal shown inFIG. 12, a maximum amplitude value in the time period from the time point T43until the time point T44is set to be smaller as compared with a maximum amplitude value in the time period from the time point T41until the time point T42. Therefore, according to the waveform of the drive signal shown inFIG. 12, when a coordinate position of an outermost point of the irradiation coordinates of the illuminating light in the time period from the time point T41until the time point T42is set as a point YMAX1, and a coordinate position of an outermost point of the irradiation coordinates of the illuminating light in the time period from the time point T43until the time point T44is set as a point YMAX2, for example, the relation of YMAX1>YMAX2 is established.

The controller25generates an image corresponding to two frames based on the respective color signals, which are outputted from the detection unit23in the time period corresponding to the time period from the time point T41to the time point T42, during the time period from the time point T43until the time point T44to cause the monitor4to display the image, while the controller25keeps control for supplying the illuminating light to the illuminating fiber12from the light source unit21, and control for supplying the drive signal to the actuator15from the driver unit22. Namely, the respective color signals that are outputted from the detection unit23during the time period corresponding to the time period from the time point T43to the time period T44do not contribute to generation of the image.

According to the third modification described above, an action similar to the action in the time period from the time point T43to the time point T44that is described above is performed every fixed time period in which scanning for obtaining the image corresponding to two frames is completed. Therefore, according to the third modification described above, the timing relating to irradiation of the illuminating light to the object, and the timing relating to generation of the image corresponding to the return light from the object can be favorably synchronized, without control or the like that temporarily stops at least any one of swing of the illuminating fiber12and supply of the illuminating light to the illuminating fiber12being performed. As a result, according to the third modification described above, stability of the frame rate at the time of observation with use of the scanning endoscope can be enhanced as compared with the conventional system.

Note that according to the present embodiment, instead of the drive signal including the waveform illustrated inFIG. 3,FIG. 7,FIG. 9orFIG. 12, a drive signal including a waveform as shown inFIG. 13, for example, may be supplied to the actuator15.FIG. 13is a diagram for explaining a fourth modification of the signal waveform of the drive signal that is supplied to the actuator provided in the scanning endoscope.

Here, a first drive signal including the waveform as shown inFIG. 13is supplied to the X axis actuator of the actuator15, and a second drive signal that is obtained by a phase of the first drive signal being shifted by 90° is supplied to the Y axis actuator of the actuator15. Thereby, in a time period from a time point T51until a time point T52, the end portion including the light exit face of the illuminating fiber12is caused to swing in such a manner as to draw a locus in a spiral shape with the point SA as a center, namely, in a sequence of the locus in the second spiral shape as illustrated inFIG. 5to the locus in the first spiral shape as illustrated inFIG. 4.

Further, the first drive signal including the waveform as shown inFIG. 13is supplied to the X axis actuator of the actuator15, and the second drive signal obtained by the phase of the first drive signal being shifted by 90° is supplied to the Y axis actuator of the actuator15. Thereby, in a time period from a time point T53until a time point T54, the end portion including the light exit face of the illuminating fiber12is caused to swing in such a manner as to draw a locus in a circular shape with the point SA as the center.

Note that according to the waveform of the drive signal shown inFIG. 13, a maximum amplitude value (a signal level) in the time period from the time point T53until the time point T54is set to include a fixed value that is larger than zero and smaller as compared with a maximum amplitude value in the time period from the time point T51until the time point T52. Therefore, according to the waveform of the drive signal shown inFIG. 13, in the time period from the time point T53until the time point T54, the end portion including the light exit face of the illuminating fiber12may be caused to swing along the locus in the circular shape ofFIG. 8, may be caused to swing along the locus in the circular shape ofFIG. 10, or may be caused to swing along the locus in the circular shape ofFIG. 11, for example.

The controller25generates an image corresponding to two frames based on the respective color signals, which are outputted from the detection unit23in the time period corresponding to the time period from the time point T51to the time point T52, during the time period from the time point T53until the time point T54to cause the monitor4to display the image, while the controller25keeps control for supplying the illuminating light to the illuminating fiber12from the light source unit21, and control for supplying the drive signal to the actuator15from the driver unit22, respectively. Namely, the respective color signals that are outputted from the detection unit23during the time period corresponding to the time period from the time point T53to the time point T54do not contribute to generation of the image.

According to the fourth modification described above, an action similar to the action in the time period from the time point T53to the time point T54that is described above is performed every fixed time period in which scanning for obtaining the image corresponding to two frames is completed. Therefore, according to the fourth modification described above, the timing relating to irradiation of the illuminating light to the object, and the timing relating to generation of the image corresponding to the return light from the object can be favorably synchronized without control or the like that temporarily stops at least any one of swing of the illuminating fiber12and supply of the illuminating light to the illuminating fiber12being performed. As a result, according to the fourth modification described above, stability of the frame rate at the time of observation with use of the scanning endoscope can be enhanced as compared with the conventional system.

The present invention is not limited to the embodiment and the modifications described above, and various changes and applications can be made within the range without departing from the gist of the invention, as a matter of course.