JP6072397B1 - Scanning endoscope device - Google Patents

Abstract

The scanning endoscope apparatus includes a light guide unit that guides illumination light and emits the light from the tip, and a drive unit that swings the tip of the light guide unit when a drive voltage is applied. A scanning unit in which the amplitude of oscillation according to the frequency of the drive voltage changes due to a temperature change, a lens that collects illumination light emitted from the tip of the light guide unit toward the subject, and a lens are held Drive that is set to a frequency that suppresses changes in the irradiation position of the illumination light on the subject due to expansion or contraction of the holding part and the lens part due to temperature change by changing the frequency characteristic of the amplitude of the light guide part due to temperature change And an applying unit that applies a voltage to the driving unit.

Description

  The present invention relates to a scanning endoscope apparatus that generates an endoscopic image by scanning illumination light.

In recent years, a scanning endoscope that acquires an image of a subject by scanning illumination light two-dimensionally with respect to the subject and detecting reflected light from the subject has been put into practical use.
The scanning scope of the scanning endoscope changes depending on the environmental temperature in which the scanning endoscope is used.
For example, Japanese Patent Application Laid-Open No. 2011-4920 as a first conventional example has a drive unit that drives the tip of an optical fiber and scans the illumination light in a spiral manner toward the observation target. In the mirror apparatus, a first temperature detection unit for detecting the temperature of the endoscope tip portion and a second temperature detection unit for detecting the outside air temperature are provided, and the detected temperature of the endoscope tip portion and the outside air temperature are detected. Based on the drive characteristics of the drive unit according to the, by performing a remapping process that converts the pixel position with a displacement to the original position, observation without distortion regardless of the temperature environment during the endoscopic work The contents for obtaining images are disclosed.
Japanese Patent Application Laid-Open No. 2014-145942 as a second conventional example is a scanning endoscope apparatus in which a temperature sensor is provided in the vicinity of an oscillating portion, and based on the temperature detected by the temperature sensor. The content which suppresses the fluctuation | variation of the angle of view by ambient temperature change by changing the drive frequency which drives a moving part is disclosed.

The first conventional example discloses that the drive characteristics of the drive unit change according to the temperature of the endoscope tip and the outside air temperature, and in accordance with the disclosure, the first and second temperature detection units are disclosed. And means for eliminating the influence of the drive characteristics by the detected temperature of the endoscope front end and the outside air temperature.
In addition, the second conventional example describes that changes in the external environment such as temperature can cause not only distortion but also fluctuations in the angle of view, and oscillation based on the temperature detected by the temperature sensor. The content which suppresses the fluctuation | variation of the view angle by the surrounding temperature change by changing the drive frequency which drives a part is disclosed.
As described above, both the first conventional example and the second conventional example are caused by substantially one main characteristic as the characteristic affected by the temperature change. Therefore, a temperature sensor for detecting the influence of the temperature change and means for reducing or eliminating the characteristic affected by the temperature change according to the detection result of the temperature sensor are indispensable.
On the other hand, by effectively using the involvement of multiple members and characteristics as characteristics affected by temperature changes, at least the temperatures actually used without making the temperature sensor etc. an indispensable component. There is a demand for a scanning endoscope apparatus that can reduce the influence of temperature changes in an environment and can acquire a high-quality image.
The present invention has been made in view of the above-described points. In an actual temperature environment, scanning that can reduce an influence of a temperature change (without providing a temperature sensor) and obtain a high-quality image. An object of the present invention is to provide a mold endoscope apparatus.

A scanning endoscope apparatus according to one embodiment of the present invention guides illumination light generated by a light source unit, emits light from a distal end, a drive voltage having a predetermined frequency is applied, and the applied drive voltage is applied toward a driving unit for vibrating oscillating the tip of the light guide portion at the predetermined frequency at a frequency of a scanning unit that having a, the illumination light emitted from the light guide portion to the subject Applying the driving voltage set to the predetermined frequency to the driving unit, the lens unit having a lens for condensing, a holding unit that holds the lens and has a space that includes the scanning unit therein and applying section for, have a, by the lens unit expands or contracts in response to temperature change, the illumination position of the illumination light in the subject, the first one of the peripheral direction or the center direction of the field of view Changed in direction and oscillated at the predetermined frequency When the amplitude of the tip of the light guide portion changes according to temperature change, the illumination position changes in the second direction of either the peripheral direction or the central direction, and the predetermined frequency is The second direction is set to be opposite to the first direction.

FIG. 1 is a diagram showing an overall configuration of a scanning endoscope apparatus according to a first embodiment of the present invention. FIG. 2 is a diagram showing a configuration around the distal end portion of the insertion portion in FIG. FIG. 3 is a cross-sectional view showing the structure of the scanning section taken along line AA in FIG. FIG. 4 is a diagram illustrating a waveform of a driving voltage for driving the driving unit. FIG. 5 is a diagram showing a locus drawn by swinging the tip of the optical fiber by the driving voltage of FIG. 4. FIG. 6 is a diagram illustrating a characteristic in which the direction of illumination light emitted from the illumination lens changes due to a change in temperature around the distal end portion of the insertion portion. FIG. 7 is a diagram illustrating frequency characteristics in which the amplitude changes when the tip of the optical fiber is vibrated in the frequency range including the resonance frequency by the scanning unit due to a change in the temperature around the tip of the insertion unit. FIG. 8 is an explanatory diagram in the case where the temperature dependence by the lens unit and the temperature dependence by the scanning unit are offset at the temperature at which the endoscopic examination is actually performed. FIG. 9 is a diagram illustrating a specific frequency that cancels out the temperature dependency of the lens unit and the temperature dependency of the scanning unit at the temperature at which endoscopy is performed. FIG. 10 is a flowchart showing the operation content of the first embodiment. FIG. 11 is a diagram illustrating a frequency range in a case where the temperature dependency by the lens unit and the temperature dependency by the scanning unit are set so as to cancel within a threshold value. FIG. 12 is a diagram showing a configuration when detecting the frequency range of FIG. 9 or FIG. 11.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
(First embodiment)
As shown in FIG. 1, the scanning endoscope apparatus 1 according to the first embodiment of the present invention includes a scanning endoscope 2 that forms a scanning optical probe and a scanning endoscope 2 that are detachably connected. A main device (or a scanning endoscope control device) 3 and a monitor 4 as a display device connected to the main device 3.
The scanning endoscope 2 includes an insertion portion 6 having an elongated shape and flexibility that can be inserted into the body or body cavity of a subject 5, and scanning is performed at the proximal end (rear end) of the insertion portion 6. A connector 7 is provided for detachably connecting the mold endoscope 2 to the connector receiver 8 of the main body device 3.
Moreover, the insertion part 6 has the hard front-end | tip part 11 and the flexible tube part 12 which has the flexibility extended to the connector 7 from the rear end. A bendable bending portion is provided between the distal end portion 11 and the flexible tube portion 12, and an operation knob or the like for bending the bending portion is provided between the proximal end of the flexible tube portion 12 and the connector 7. An operation unit may be provided.

The distal end portion 11 has a cylindrical member 13 that forms a hard holding portion, and the distal end of a cylindrical tube that forms a flexible flexible tube portion 12 is connected to the rear end of the cylindrical member 13. The rear end is fixed to the connector 7. The cylindrical member 13 is formed using a hard member such as stainless steel. The cylindrical member 13 is a lens holding cylinder that holds an illumination lens 16 described later.
An optical fiber 15 that forms a light guide for guiding illumination light is inserted into the insertion portion 6, and a base end (rear end) of the optical fiber 15 is an optical fiber 15 b inside the main body device 3 at the connector 7. Connected. The illumination light generated in the light source unit 31 forming the light source unit inside the main body device 3 is incident on the proximal end of the optical fiber 15 through the optical fiber 15b. Illumination light incident on the proximal end of the optical fiber 15 is guided (transmitted) to the distal end (or distal end surface) serving as the exit end of the optical fiber 15, and from the distal end facing the distal end of the cylindrical member 13. Illumination light is emitted toward an observation target site in the subject 5 through a condensing illumination lens 16 attached to the tip.
FIG. 2 shows a configuration near the tip 11. In FIG. 2, the structure of the inner side part of the cylindrical member 13 of the front end part 11 is shown.

Inside the cylindrical member 13, a scanning unit (or scanning unit) that scans the distal end side of the optical fiber 15 so as to swing in a direction orthogonal to the longitudinal direction of the optical fiber 15 (Z-axis direction in FIG. 1). An actuator 17 forming a drive unit 14 is arranged. The scanning unit 14 includes an optical fiber 15 that forms a light guide unit (a tip side portion thereof), and an actuator 17 that forms a drive unit that swings the tip of the optical fiber 15 according to an applied drive voltage. It is formed by.
Further, an illumination lens 16 that forms a lens for condensing illumination light emitted from the tip of the optical fiber 15 toward the subject 5, and a space that holds the illumination lens 16 and encloses the scanning unit 14 therein. The cylindrical member 13 forming the holding portion having the lens portion 21 forms the lens portion 21. As shown in FIG. 2, the illumination lens 16 includes a convex lens 16a disposed on the distal end side at a distance (or distance) d from the distal end of the optical fiber 15, and a convex lens 16b disposed further on the distal end side of the convex lens 16a. Consists of The interval d is a value at a normal temperature of about 25 ° C. (the temperature is represented by T1), for example.

When the distal end portion 11 is inserted into the subject 5 and becomes the temperature in the body of about 35 ° C. (the temperature is represented by T2), which is the environmental temperature when endoscopy is performed, the lens portion 21 is moved. The irradiation position when the illumination lens 16 to be formed and the cylindrical member 13 (and the holding member 19) are affected by the temperature rise, and the irradiation position (or illumination position) of the illumination light formed on the subject 5 side is the temperature T1. To the irradiation position in the peripheral direction where the field of view expands. In the present specification, the irradiation position and the illumination position have the same meaning.
In the case of FIG. 2, the state where the tip of the optical fiber 15 is vibrated in the vertical direction, for example, with a constant amplitude value that is close to the maximum amplitude corresponding to the maximum field of view (with respect to temperature change) is maintained. When the distal end portion 11 is changed from the temperature T1 to the temperature T2, the lens portion 21 having the cylindrical member 13 and the illumination lens 16 indicates the irradiation positions P1 and P2 on the subject 5 at the temperature T1 with arrows. Thus, the temperature dependency is shown such that the irradiation position on the peripheral side where the field of view (or viewing angle) expands is changed (moved).
In the present embodiment, the field of view is used as a phrase representing the range inside the maximum field of view. This field of view is on the inner side of the irradiation position in the case of the maximum field of view (the irradiation position in the case of forming the maximum spiral (maximum angle of view that is approximately the maximum circle) when performing spiral scanning). This corresponds to the irradiation position when the range is scanned. As will be described later, the scanning unit 14 also has a temperature dependency with respect to a temperature change in which the amplitude at which the tip of the optical fiber 15 is vibrated or the irradiation position of the illumination light when irradiated through the illumination lens 16 toward the subject 5 changes. Have

The actuator 17 constituting the scanning unit 14 is applied with an alternating drive voltage (or drive signal) from the drive unit 32 inside the main body device 3 via the drive lines 18 a and 18 b inserted through the insertion unit 6. Thus, it expands and contracts in the longitudinal direction.
The base end of the actuator 17 is held by a holding member 19, and the disc-shaped outer peripheral surface of the holding member 19 is fixed to the inner surface of the cylindrical member 13. The optical fiber 15 and the actuator 17 are joined by a ferrule 20 (see FIG. 3) as a joining member or a supporting member.
FIG. 3 shows the configuration of the peripheral portion of the actuator 17 along the line AA in FIG. As shown in FIG. 3, the ferrule 20 as a hard joint member having a rectangular parallelepiped shape having a square cross section disposed along the central axis O (in the cylindrical member 13) is formed of, for example, zirconia (ceramic) or nickel. ing.
The ferrule 20 fixes the optical fiber 15 disposed in the hole along the central axis O, and both side surfaces in the Y-axis direction (vertical or vertical direction on the paper surface) orthogonal to the Z-axis and the X-axis direction (on the paper surface). Actuator elements 17a, 17b and 17c, 17d forming the actuator 17 are attached to both side surfaces (left and right or in the horizontal direction).

Each actuator element is composed of, for example, a piezoelectric element, and expands and contracts in the longitudinal direction when a driving voltage is applied to electrodes (not shown) on both sides of the piezoelectric element. Accordingly, in a state where the base end is held or fixed, for example, by applying a driving voltage (or a driving signal) to the actuator elements 17a and 17b via the driving line 18a (extending one and contracting the other), FIG. 1, the tip side of the optical fiber 15 can be swung (or vibrated) in the vertical direction. For example, in FIG. 1, the output signals of the amplifiers 32d and 32e are applied to the actuator 17 (actuator elements 17a, 17b and 17c, 17d) through the drive lines 18a and 18b. FIG. 2 also shows a case where the tip end side of the optical fiber 15 is swung (vibrated) in the vertical direction.
4 shows waveforms of drive voltages applied to the actuator elements 17a, 17b and 17c, 17d, and the tip of the optical fiber 15 has a spiral (or spiral) path (or locus) as shown in FIG. Draw. As shown in FIG. 4, the drive voltage phases in the X-axis direction and the Y-axis direction are applied to the actuator elements 17a, 17b, 17c, and 17d in a state of being shifted by 90 °, and the drive voltage is changed little by little with time. The tip of the optical fiber 15 draws a circular or spiral locus.

In the present embodiment, the actuator 17 is formed by using a pair of actuator elements 17a and 17b and actuator elements 17c and 17d in order to swing (vibrate) in two orthogonal directions. The present invention can also be applied to the case where one actuator element (for example, 17a and 17c) is used.
The actuator 17 constituting the scanning unit 14 has a characteristic that the amplitude changes when the tip of the optical fiber 15 is swung (or vibrated) due to a temperature change. In this case, the influence of the temperature change varies depending on the drive frequency (also simply referred to as frequency) of the drive voltage (the alternating current whose polarity changes) that drives the actuator 17. Usually, the driving frequency of the (alternating current) driving voltage for driving the actuator 17 is set in the peripheral portion of the resonance frequency fr of the scanning unit 14 (in this case, the optical fiber 15 is more efficiently driven by the applied driving voltage. Can be swung greatly.)
In the present embodiment, as will be described in detail later, by appropriately setting the drive frequency for driving the actuator 17 constituting the scanning unit 14, the lens unit 21 emits illumination light on the subject 5 due to a temperature change. By offsetting the influence of the position change, the irradiation position of the illumination light is suppressed from being shifted due to a temperature change.

As shown in FIG. 1, a light receiving optical fiber bundle (abbreviated as a light receiving optical fiber) for receiving illumination light reflected on the side of the examination site of the subject 5 along the outer peripheral surfaces of the cylindrical member 13 and the cylindrical tube. Return light (or reflected light) (or from the observation target site side of the subject 5) arranged in a ring shape and received by the light receiving optical fiber 23 passes through the connector 7 and passes through the connector 7. The light is guided to the light receiving optical fiber 23b. The return light guided to the light receiving optical fiber 23b enters the detection unit 33 and is converted into an electric signal.
The light receiving optical fiber 23 arranged in a ring shape is covered and protected by a flexible exterior member 24.
Further, in each scanning endoscope 2, the actuator 17 drives the driving data for driving the tip of the optical fiber 15 along a predetermined scanning pattern having a spiral shape, and the irradiation position (or scanning position) when driven. 2 has a memory 25 that stores information such as two-dimensional coordinate position data (also referred to as mapping data). The information stored in the memory 25 is input to the controller 34 in the main body device 3 through the contacts and signal lines of the connector 7. The controller 34 stores the input information in the memory 35, for example, and refers to the information stored in the memory 35 to control the light source unit 31, the drive unit 32, and the like.

Further, the return light (or reflected light) reflected at the irradiation position of the illumination light irradiated on the subject 5 side is detected by the light receiving optical fiber 23 and is photoelectrically converted by the detection unit 33 as a return light signal. The image is input to the image generation unit 34 c in the controller 34. Then, the image generation unit 34c refers to the mapping data read from the memory 25 and stored in the memory 35, and the return light signal is converted into a pixel signal associated with the irradiation position of the illumination light.
For this reason, for example, when mapping data is generated at the temperature T1, when the irradiation position of the illumination light changes when the temperature T1 changes to the temperature T2, if the mapping data generated at the temperature T1 is used, the actual irradiation position is shifted. Since an image is generated as the irradiated position, the image quality deteriorates. On the other hand, if the irradiation position of the illumination light at the temperature T2 is set so as to be substantially the same position as that at the temperature T1, the irradiation position of the illumination light can be determined even using the mapping data generated at the temperature T1. Since it does not change, an image with good image quality can be generated.

In the present embodiment, as described below, mapping data is generated at least at the temperature T2 in the body, which is the environmental temperature at which the endoscopy is actually performed, by effectively using different temperature characteristics of a plurality of components. By setting so that the irradiation position of the illumination light at the temperature (T1 in the present embodiment) substantially matches, an image with good image quality can be generated or acquired.
The memory 25 provided in each scanning endoscope 2 stores in advance information on a specific frequency fd when driving the actuator 17 mounted on each scanning endoscope 2 at the time of factory shipment or the like. Storing. For this reason, the memory 25 forms a storage unit or a storage unit that stores information of the specific frequency fd. The configuration for detecting the specific frequency fd and storing it in the memory 25 will be described later with reference to FIG.
The main unit 3 includes a light source unit 31, a drive unit 32, a detection unit 33, a controller 34 that controls each unit of the main unit 3, and a memory 35 that is connected to the controller 34 and stores various types of information. Have. Further, an input unit (or input unit) 36 through which a user performs various input instructions is connected to the controller 34 of the main body device 3. The input unit 36 includes a keyboard, a mouse, and the like.

The light source unit 31 includes an R light source 31a that generates light in a red wavelength band (also referred to as R light), a G light source 31b that generates light in a green wavelength band (also referred to as G light), and a blue wavelength band. It has a B light source 31c that generates light (also referred to as B light) and a multiplexer 31d that combines (mixes) R light, G light, and B light.
The R light source 31a, the G light source 31b, and the B light source 31b are configured using, for example, a laser light source and the like, and respectively emit R light, G light, and B light to the multiplexer 31d. The controller 34 includes a light emission control unit (or light emission control circuit) 34a including a central processing unit (abbreviated as CPU) that controls pulse light emission of the R light source 31a, the G light source 31b, and the B light source 31b.
The light emission control unit 34a that performs light emission control on the R light source 31a, the G light source 31b, and the B light source 31b further emits R light, G light, and B light (illumination light thereof) from the emission end of the optical fiber 15 when emitted. The light is emitted to the observation region side through the illumination lens 16.
The light emission control unit 34a of the controller 34 sends a control signal for causing the R light source 31a, the G light source 31b, and the B light source 31b to emit light in pulses at the same time, and the R light source 31a, the G light source 31b, and the B light source 31b G light and B light are generated and emitted to the multiplexer 31d.

The multiplexer 31d combines the R light from the R light source 31a, the G light from the light source 31b, and the B light from the light source 31c, and supplies the combined light to the light incident surface of the optical fiber 15b. Supplies the combined R light, G light, and B light to the optical fiber 15 as illumination light.
The drive unit 32 includes a signal generator 32a that generates a digital AC signal close to a sine wave, and the digital AC signals output from the two output terminals of the signal generator 32a are two D / A converters 32b. , 32c. The two analog AC signals converted by the two D / A converters 32b and 32c are amplified by the amplifiers 32d and 32e, respectively, to become two drive voltages (or drive signals), and the drive lines 18a and 18b. Are applied to the actuator elements 17a and 17b and 17c and 17d, respectively.
The signal generator 32a has a built-in voltage controlled oscillator (VCO) 32f whose oscillation frequency can be varied by, for example, a voltage value input from the input terminal.
A drive control unit 34 b provided in the controller 34 controls the oscillation frequency of the signal generator 32 a of the drive unit 32. The drive control unit 34 b and the drive unit 32 form an application unit that applies a drive voltage with a specific frequency fd to the drive frequency to the actuator 17 of the scanning unit 14 to swing the tip of the optical fiber 15. .

The drive control unit 34b constituting the application unit changes the illumination position of the illumination light in the subject 5 caused by expansion or contraction of the lens unit 21 due to a temperature change, and the scanning unit 14 moves the tip of the optical fiber 15 due to the temperature change. The amplitude when the oscillation is changed changes (and the irradiation position of the illumination light that changes with the amplitude change thereby changes) and is suppressed by canceling using the frequency characteristic of the drive voltage. In order to describe the function of the application unit, first, a change in the irradiation position of the illumination light due to a temperature change in the lens unit 21 will be described.
As described above, when the illumination lens 16 forming the lens portion 21 and the cylindrical member 13 (and the holding member 19) are affected by the temperature rise, the irradiation position of the illumination light formed on the subject 5 side is the temperature T1. Changes from the irradiation position to the irradiation position in the peripheral direction where the field of view expands.
Actually, the cylindrical member 13 forming the holding portion in the lens portion 21 expands or contracts due to the temperature change, and the distance d from the tip of the optical fiber 15 to the convex lens 16a is changed. Is a major factor when changes occur. The cylindrical member 13 expands and contracts mainly in the longitudinal direction due to a temperature change, and as a result, the distance d from the tip of the optical fiber 15 to the convex lens 16a is changed.
In the case of FIG. 2, when the temperature T1 changes to the temperature T2, the cylindrical member 13 expands (extends) in the longitudinal direction as indicated by a two-dot chain line, so that the positions of the convex lenses 16a and 16b are also indicated by the two-dot chain line. And the interval d (at temperature T1) increases as indicated by d '. And the irradiation position of P1 and P2 changes (moves) to the irradiation position of the peripheral side (or outer side) direction which expands a visual field.

FIG. 6 shows how the irradiation position or field of view of the lens unit 21 changes due to temperature changes. As shown in FIG. 6, the irradiation position P (or visual field θ) in the Y-axis direction at the temperature T1, for example, is a change characteristic V when the temperature changes, and the periphery where the visual field expands when the temperature increases. It changes (moves) to the irradiation position on the side. 6 shows, for example, the irradiation position when the temperature is raised in a state where the tip of the optical fiber 15 is set to a constant amplitude close to the scanning range or maximum visual field in the Y-axis direction as described in FIG. Alternatively, the state of the field of view is shown (in practice, the scanning unit 14 side also has a temperature-dependent characteristic).
Note that the irradiation position is similarly changed not only in the Y-axis direction but also in the X-axis direction and the like. That is, the lens unit 21 exhibits change characteristics V as shown in FIG. 6 with respect to an arbitrary direction in a plane perpendicular to the central axis passing through the optical axis of the illumination lens 16 or the central axis of the optical fiber 15.
Further, the rate of change of the irradiation position P or the visual field θ due to the temperature change from the temperature T1 to T2 is about 5% in the vicinity of the scanning range or the maximum visual field, and is closer to the inside or the center than the vicinity of the end of the scanning range or the maximum visual field. In the irradiation position or field of view, the effect becomes small, and the effect can be approximated to be approximately proportional to the amplitude value or the size of the field of view.

Therefore, at the irradiation position P corresponding to the case of the maximum amplitude or close to this, for example, when the temperature is changed from the temperature T1 to the temperature T2, a device (setting) is made so as to eliminate the deviation of the irradiation position P at both temperatures. Then, even when the illumination light is scanned with an amplitude smaller than the maximum amplitude, the deviation of the irradiation position at both temperatures can be substantially eliminated.
In other words, by setting the maximum amplitude or the end of the scanning range or in the vicinity of the maximum visual field so as to suppress or eliminate the influence of the temperature change, the irradiation position or visual field inside the scanning range from the peripheral side of the scanning range. The influence due to the temperature change can be substantially suppressed or eliminated.
On the other hand, FIG. 7 shows the tip of the optical fiber 15 when the driving frequency for driving the actuator elements 17a and 17b of the actuator 17 is swept in the frequency range including the resonance frequency fr (T1) at the temperature T1. A change curve C1 (T1) of the amplitude A in the Y-axis direction is shown.

Similarly, at the temperature T2, the drive frequency for driving the actuator elements 17a and 17b of the actuator 17 is swept in the frequency range including the resonance frequency fr (T2), and the optical fiber 15 in the Y-axis direction is swept. A change curve C2 (T2) of the amplitude A at the tip is also shown. Even when the actuator elements 17c and 17d are driven, the characteristics are almost the same as those shown in FIG. That is, the characteristics shown in FIG. 7 are obtained in an arbitrary direction in a plane perpendicular to the central axis passing through the central axis of the optical fiber 15.
The amplitude A corresponds to the irradiation position or visual field of the illumination light on the subject 5, and the larger the amplitude A is, the larger the irradiation position or the larger visual field on the peripheral side. By adopting the illumination lens 16 shown in FIG. 2 or a lens having the same characteristics as this (for example, analysis by simulation or evaluation), the change in the amplitude A can be converted into the change amount of the irradiation position of the illumination light.
As can be seen from the change curves C1 (T1) and C2 (T2) in FIG. 7, the resonance frequency fr (T1) is the lower resonance frequency with respect to the temperature change in which the temperature rises from the temperature T1 to the temperature T2. It changes to fr (T2). In this case, the change curve C2 (T2) is close to the characteristic obtained by shifting (translating) the change curve C1 (T1) to the lower frequency side.

In the case of the change curves C1 (T1) and C2 (T2) in FIG. 7, for example, the amplitude A1 when the actuator elements 17a and 17b are driven at the resonance frequency fr (T1) has the temperature T from T1 to T2. If it changes, it will fall to amplitude A2.
On the other hand, for example, the amplitude A3 when the actuator elements 17a and 17b are driven at a frequency slightly higher than the resonance frequency fr (T1) decreases to the amplitude A4 when the temperature T is changed from T1 to T2. If the characteristic in this case is expressed using the irradiation position, when the temperature rises, the irradiation position changes to the irradiation position in the direction of reducing the field of view (or the irradiation position in the center side direction).
In other words, when the temperature rises, the cylindrical member 13 holding the illumination lens 16 in the lens unit 21 expands to widen the distance d between the illumination lens 16 and the irradiation position as shown in FIG. Whereas P functions to change the irradiation position in the peripheral side direction that expands the field of view, for example, when a drive voltage having a drive frequency higher than the resonance frequency fr (T1) is applied to the actuator 17, The irradiation position is changed to the irradiation position in the central direction that narrows the field of view.

Therefore, by setting the driving frequency of the driving voltage applied to the actuator 17 to an appropriate frequency by the applying unit, the change in the irradiation position from the temperature T1 by the lens unit 21 at the temperature T2 can be offset.
FIG. 8 shows the change characteristic V of FIG. 6 and the change characteristic C representing the change curves C1 (T1) and C2 (T2) of FIG. 7, and the irradiation position P or field of view θ at the temperature T1 is at the temperature T2. The figure which adjusted the change characteristic C so that it may become the same irradiation position or a visual field is shown. In FIG. 8, the change curves C1 (T1) and C2 (T2) whose amplitude changes with temperature in FIG. 7 are converted into change characteristics C whose irradiation position changes with temperature.
In FIG. 8, a change characteristic V indicates a characteristic in which the irradiation position P shifts to the irradiation position in the peripheral direction in which the field of view is enlarged when the temperature rises. Further, in the change characteristic V, the amount of change from the irradiation position P of the temperature T1 when changing from the temperature T1 to the temperature T2 is represented by Δ1. On the other hand, the change characteristic C indicates a characteristic in which the irradiation position shifts to the irradiation position in the central direction that reduces the visual field when the temperature rises. In the change characteristic C, the change amount from the irradiation position P of the temperature T1 when the temperature T1 is changed to the temperature T2 is represented by -Δ2.

The change amounts Δ1 and −Δ2 have different polarities. Therefore, the irradiation position changes or the field of view changes due to the temperature change in the vicinity of the temperature T2 by equalizing the sum of the changes Δ1 and −Δ2, Δ1−Δ2 or absolute values | Δ1 | and | −Δ2 | This can be offset and suppressed.
FIG. 9 shows a specific frequency fd when the sum of the change amounts Δ1 and −Δ2 is set to 0 at the temperature T2. The memory 25 of the scanning endoscope 2 stores in advance information of a specific frequency fd as a driving frequency of a driving voltage applied to the actuator 17 of the scanning endoscope 2 at the temperature T2.
In the memory 25, for example, the temperature at which the actuator 17 of the scanning endoscope 2 is scanned along the spiral scanning trajectory at the temperature T1, and the irradiation position at the timing at which the light is emitted are stored. It also stores mapping data as related data.
When the scanning endoscope 2 is connected to the main body device 3, the controller 34 in the main body device 3 reads the mapping data stored in the memory 25 and information on the specific frequency fd and stores them in the memory 35. To do. Then, the controller 34 drives the actuator 17 by setting the drive frequency of the drive voltage applied to the actuator 17 of the scanning endoscope 2 connected to the main body device 3 to a specific frequency fd.

  The scanning endoscope apparatus 1 according to the first embodiment of the present invention guides illumination light generated by a light source unit 31 that forms a light source unit, and forms an optical fiber 15 that forms a light guide unit that emits light from the tip. And an actuator 17 that forms a drive unit to which a drive voltage is applied, vibrates at a frequency of the applied drive voltage, and swings the tip of the light guide unit, and a temperature (from a first temperature). The scanning unit 14 in which the amplitude of the swing of the tip of the light guide unit changes according to the frequency of the drive voltage due to the change, and the illumination light emitted from the light guide unit is collected toward the subject 5. A lens unit 21 having an illumination lens 16 that forms a lens to be formed, and a cylindrical member 13 and a holding member 19 that form a holding unit that holds the lens and has a space that includes the scanning unit 14 therein. The scanning unit 14 and the lens unit The temperature at which the distal end portion 11 of the scanning endoscope 2 provided with 1 is different from the first temperature set at the time of endoscopic examination or in the vicinity of the second temperature) A change in the illumination position of the illumination light in the subject 5 caused by expansion or contraction of the lens unit 21 due to a change is set to a frequency that is suppressed by a change in frequency characteristics of the amplitude of the light guide unit tip due to the temperature change. The drive control unit 34b and the drive unit 32 form an application unit that applies the drive voltage to the drive unit.

Next, the operation of this embodiment will be described. FIG. 10 shows the processing contents in the case of a typical operation in the present embodiment.
The surgeon connects the scanning endoscope 2 to the main unit 3 as shown in the first step S1, and turns on the main unit 3. Then, in step S <b> 2, the controller 34 enters an operating state, and reads information from the memory 25 in the scanning endoscope 2 connected to the main body device 3. That is, the controller 34, together with the mapping data, has a frequency that cancels the characteristic at the temperature T2 with respect to the characteristic that the irradiation position changes when the temperature of the cylindrical member 13 that shows the main temperature dependence in the lens unit 21 rises. Information on a specific frequency fd is read out and stored in the memory 35.
In step S <b> 3, the controller 34 (the drive control unit 34 b) sets the read specific frequency fd as the drive frequency of the drive voltage applied from the drive unit 32 to the actuator 17.
As shown in step S4, the operator inserts the insertion portion 6 into the subject 5 from the distal end portion 11 side. As shown in step S5, when the tip 11 is inserted into the subject 5, the temperature near the tip 11 becomes a temperature near T2.

As shown in step S6, the drive control unit 34b of the controller 34 controls the drive unit 32 to drive the actuator 17 with a drive voltage having a specific frequency fd. The actuator 17 swings the tip of the optical fiber 15 in a spiral shape, and the irradiation position of the illumination light irradiated on the subject 5 moves in a spiral shape.
As described above, when the temperature rises, the cylindrical member 13 expands, and the distance d from the tip of the optical fiber 15 shown in FIG. 2 to the first convex lens 16a in the illumination lens 16 becomes wider (or larger). Although the irradiation position to be shown is shifted as indicated by an arrow on the peripheral side, as described above, the application unit cancels the deviation of the irradiation position by setting the drive frequency to the specific frequency fd. That is, as shown in step S7, the application unit functions to cancel the deviation of the irradiation position with respect to the temperature change from the temperature T1 to T2.
As shown in step S8, the reflected light or return light reflected at the irradiation position of the subject 5 is input to the detection unit 33 and detected as a return light signal subjected to photoelectric conversion.

As shown in step S <b> 9, the return light signal is input to the image generation unit 34 c in the controller 34. The image generation unit 34c refers to the mapping data and converts the return light signal into a signal value of the irradiation position. In other words, the image generation unit 34c refers to the mapping data, converts the signal value of the return light signal into a pixel signal or image signal data at a pixel position representing the two-dimensional position, and further converts it into an image signal for raster scanning. And output to the monitor 4.
As shown in step S10, the monitor 4 displays the image of the input image signal as an endoscopic image. Then, the process of FIG.
Note that the order of steps S3 and S4 may be interchanged. Next, the processing content of step S7 in FIG. 10 will be supplementarily described.
As described above, when the temperature rises, the lens unit 21 has an irradiation position of the illumination light irradiated on the subject 5 through the illumination lens 16 as shown in FIG. Change (move) to the irradiation position. As a main factor in this case, as shown in FIG. 2, when the temperature rises, the cylindrical member 13 expands (expands) in the longitudinal direction, so that the distance d from the tip of the optical fiber 15 to the convex lens 16a is widened. In addition, the irradiation position on the subject 5 (P1, P2 in FIG. 2) moves (changes) to the peripheral side (outside), which is the direction in which the field of view is enlarged, as indicated by the arrows.

On the other hand, when the drive frequency of the drive voltage applied to the actuator 17 is set to a frequency higher than the resonance frequency fr (T1) at the temperature (for example, T1) before the temperature is raised, the tip of the optical fiber 15 is swung. The amplitude of the tip of the optical fiber 15 changes so that the amplitude decreases as the temperature rises.
In this embodiment, as shown in FIG. 9, by setting the drive frequency of the drive voltage applied to the actuator 17 to a specific frequency fd when the change amount Δ1-Δ2 shown in FIG. When the scanning endoscope 2 is inserted into the subject 5 and the endoscopic examination is performed, the irradiation position of the illumination light changes when the temperature rises from the temperature T1 to the temperature T2 within the subject 5. It is possible to effectively prevent the deviation from the irradiation position at T1.
That is, according to the present embodiment, it is possible to realize the scanning endoscope apparatus 1 that can acquire an image with good image quality with little influence of temperature change in a temperature environment that is actually used.
Further, according to the present embodiment, when the temperature of the distal end portion 11 is known when it is inserted into the subject 5 and subjected to endoscopy, there is no need to provide a temperature sensor near the distal end portion 11. It is easy to reduce the diameter of the tip 11.

9 shows an example in which the specific frequency fd is set when the change amount Δ1-Δ2 becomes 0 at the temperature T2, but as shown in FIG. 11, in the body temperature environment near the temperature T2, A threshold value may be provided so that the change amount Δ1−Δ2 can be set to a driving frequency within an allowable range.
As shown in FIG. 11, the change amount Δ1−Δ2 may be set to a drive frequency within a frequency f1 to f2 in a range in which the change is equal to or less than the positive threshold th1 and equal to or greater than the negative threshold −th1 in the environment of body temperature.
Next, a configuration for detecting the above-described specific frequency fd or a drive frequency within f1 to f2 will be described with reference to FIG.
A scanning endoscope apparatus 1B shown in FIG. 12 is the same as the scanning endoscope apparatus 1 shown in FIG. 1, and further includes a heater 51 for heating the vicinity of the distal end portion 11 from the temperature T1 to at least a temperature near the temperature T2, and the distal end portion. 11, a reference screen (or chart) 52 for detecting an irradiation position (or for visual field detection) having a plane perpendicular to the central axis of the optical fiber 15 and facing the longitudinal direction of the optical fiber 15, and disposed on the back surface of the reference screen 52. The relationship between the drive frequency and the irradiation position is determined by a two-dimensional position sensor (hereinafter simply referred to as a sensor) 53 that detects the two-dimensional position of the irradiation position of the illumination light irradiated on the reference screen 52 and the output of the sensor 53. And a drive frequency / irradiation position (or field of view) analysis device 54 for analysis. The drive frequency / irradiation position analyzing device 54 can be configured by a personal computer or the like.

In addition, the drive frequency / irradiation position analyzing device 54 is connected to the controller 34 of the main body device 3 through a communication line, and when the controller 34 (the drive control unit 34b) changes the drive frequency to sweep, the drive frequency / irradiation position analyzing device 54 Information is transmitted to the drive frequency / irradiation position analyzer 54.
The signal line 55 that connects the memory 25 and the controller 34 is also connected to the drive frequency / irradiation position analyzer 54. Then, when the drive frequency / irradiation position analyzing device 54 analyzes the relationship between the drive frequency and the irradiation position and detects the specific frequency fd, the drive frequency / irradiation position analysis device 54 stores the specific frequency fd in the memory 25 via the signal line 55. Write information. When the drive frequency / irradiation position analyzing device 54 detects the specific frequency fd, the information may be transmitted to the controller 34 and the controller 34 may write the information of the specific frequency fd into the memory 25. In the following description, for example, the temperature T1 is assumed to be a temperature when mapping data is generated.

First, at the temperature T1 before the heater 51 is operated, the drive control unit 34b sweeps the drive frequency and applies the drive voltage to the actuator 17, and the irradiation position of the illumination light irradiated on the reference screen 52 is detected by the sensor 53. Detected. Then, the sensor 53 sends information on the detected irradiation position to the drive frequency / irradiation position analyzer 54. The drive frequency / irradiation position analysis device 54 analyzes information on the relationship between the drive frequency and the irradiation position, calculates information on the relationship between the drive frequency and the irradiation position in the case of the temperature T1, and the inside of the drive frequency / irradiation position analysis device 54 Save to memory.
The above process is repeated by changing the value of the drive voltage, for example, in the drive voltage near the maximum visual field.
Next, the drive frequency / irradiation position analyzer 54 controls the heater 51 to operate so that the temperature of the distal end portion 11 is raised to the internal temperature T2. The drive frequency / irradiation position analyzer 54 recognizes that the tip 11 has reached the temperature T2 by a temperature sensor (not shown), and sends the information of the controller 34 to the drive controller 34b.

Then, similar to the case of the temperature T1, the same processing as described above is repeatedly performed at the temperature T2.
Then, in the case of the temperature T1 and the temperature T2, when the drive voltage is the same value, the drive frequency with which the irradiation position matches is determined as the specific frequency fd.
In the scanning endoscope apparatus 1B shown in FIG. 12, when the temperature of the distal end portion 11 is changed, the cylindrical member 13 forming the lens portion 21 expands or contracts to illuminate the reference screen 52. Illumination light irradiated on the reference screen 52 due to the influence of the change in the light irradiation position and the amplitude when the tip of the optical fiber 15 is swung by the scanning unit 14 (at the tip of the optical fiber 15). Therefore, the driving frequency at which the irradiation position is the same at the temperature T2 with the same driving voltage as the temperature T1 becomes the specific frequency fd.
Then, the drive frequency / irradiation position analyzing apparatus 54 writes the information of the determined specific frequency fd directly into the memory 25 or writes it into the memory 25 via the controller 34.

In the above-described embodiment, for example, when the lens unit 21 changes the irradiation position in the direction in which the field of view is enlarged due to a temperature rise, the drive frequency of the drive voltage applied to the actuator 17 is increased before the temperature rises. Is set to a frequency higher than the resonance frequency (fr (T1) in the specific example of FIG. 7), so that the distal end portion 11 (provided with the scanning unit 14 and the lens unit 21) is set at the time of endoscopy. A specific example has been described in which the effect of changing the irradiation position due to a temperature change at the temperature T2 can be offset.
However, the present invention is not limited to the above-described specific example. For example, even when the lens unit 21 changes the irradiation position in the direction in which the field of view is reduced due to a temperature rise, the resonance before the temperature rises. By setting the frequency lower than the frequency (fr (T1) in the specific example of FIG. 7), the distal end portion 11 (provided with the scanning unit 14 and the lens unit 21) is set at the time of endoscopy. It is also possible to cancel the influence that the irradiation position changes due to the temperature change at the temperature T2.
However, a part of the frequency range lower than the resonance frequency before the temperature rise (fr (T1) in the specific example of FIG. 7) (in FIG. 7, change curves C1 (T1) and C2 (T2)) By setting in the frequency range below the driving frequency at which the two intersect, the tip portion 11 (provided with the scanning unit 14 and the lens unit 21) is irradiated by a temperature change at a temperature T2 set at the time of endoscopy. The effect of changing the position can be offset. In addition, in order to cope with the case where the temperature in the subject is different, information on a plurality of specific frequencies in which Δ1−Δ2 is in the range of 0 or a threshold value or less at each of a plurality of temperatures is stored in a storage unit such as the memory 25. You may make it store.
Further, based on the description of the present specification, the content of the claims as shown in the following supplementary notes can be made.

[Appendix 1]
A light guide unit that guides the illumination light generated by the light source unit and emits it from the tip, and a drive unit that is applied with a drive voltage and vibrates at the frequency of the applied drive voltage to swing the tip of the light guide unit And a scanning unit in which the amplitude of the oscillation of the tip of the light guide unit changes according to the frequency of the drive voltage due to a temperature change from the first temperature T1 as a reference,
A lens unit that condenses the illumination light emitted from the light guide unit toward a subject, and a holding unit that holds the lens and includes a space that includes the scanning unit therein;
Illumination of the illumination light on the subject caused by expansion or contraction of the lens portion due to the temperature change at a temperature T2 at which the scanning unit and the lens unit reach inside the subject (different from the temperature T1) The drive voltage set to the same value as the case of the temperature T1 with the drive voltage set to a specific frequency that suppresses the change in position by the change in the frequency characteristic of the amplitude of the light guide tip due to the temperature change An application unit for applying to the drive unit;
A scanning endoscope apparatus comprising:
[Appendix 2]
At the first temperature, illumination light is irradiated to the subject side through the lens unit when the driving unit is driven so that the scanning unit scans along a predetermined spiral scanning trajectory. A mapping data storage unit that stores in advance the information of the two-dimensional coordinate position of each illumination position as mapping data,
The scanning endoscope apparatus according to appendix 1, wherein the application unit applies a driving voltage under the same condition as the temperature T1 at the specific frequency at the temperature T2.
[Appendix 3]
A return light signal is generated by detecting a return light of illumination light applied to the subject by applying the drive voltage at the specific frequency, and the mapping (generated at the temperature T1) is generated from the return light signal. The scanning endoscope apparatus according to appendix 2, wherein the data is converted into an image signal using data.

  This application is filed on the basis of the priority claim of Japanese Patent Application No. 2015-124908 filed in Japan on June 22, 2015, and the above disclosed contents include the present specification, claims, It shall be cited in the drawing.

Claims (12)

Guided illumination light source unit is generated, and a light guide section that emits from the distal end, the driving voltage of a predetermined frequency is applied to vibrate at a frequency of the applied driving voltage to the tip of the light guide portion a scanning unit that having a, a driving unit for swinging at a predetermined frequency,
A lens unit that condenses the illumination light emitted from the light guide unit toward a subject, and a holding unit that holds the lens and includes a space that includes the scanning unit therein ;
An application unit that applies the drive voltage set to the predetermined frequency to the drive unit;
I have a,
When the lens unit expands or contracts in accordance with a temperature change, the illumination position of the illumination light in the subject changes in the first direction of either the peripheral direction or the central direction of the visual field,
The illumination position changes in the second direction of either the peripheral direction or the central direction by changing the amplitude of the tip of the light guide section oscillated at the predetermined frequency according to a temperature change. And
The scanning endoscope apparatus according to claim 1, wherein the predetermined frequency is set so that the second direction is opposite to the first direction . The temperature change is a temperature increase from a first temperature to a second temperature higher than the first temperature;
Said scanning unit, by the temperature rise, chromatic said amplitude of the light guide portion resonance frequency that Do a peak low Kunar frequency characteristics at the time of sweeping the frequency of the drive voltage applied to the drive unit And
The lens unit, by the temperature rise, a position variation characteristics illumination position changes of the illumination light in a direction the visual field of the scanning endoscope is enlarged,
The scanning endoscope apparatus according to claim 1, wherein the application unit sets the predetermined frequency to a value larger than the resonance frequency of the first temperature . The scanning unit is inserted into the body of the subject,
The application unit is configured to cancel the change in the illumination position of the illumination light in the subject caused by expansion or contraction of the lens unit due to insertion of the scanning unit into the body of the subject. The scanning endoscope apparatus according to claim 1, wherein the driving voltage set at a frequency at which the amplitude of the swing of the tip changes is applied. The lens portion has a gap widens characteristics between the tip and the lens of the light guide portion by the holding portion by the temperature rise is inflated,
The application section, scanning according to claim 2, characterized in that for applying the driving voltage having a frequency of suppressing a change in the illumination position caused by the expansion of the holding portion due to the temperature rise in the drive unit Endoscopic device. The scanning unit and the lens unit are provided at a distal end of an insertion unit that is inserted into the subject in a scanning endoscope,
For the first change characteristic V in which the illumination position of the illumination light in the subject changes due to expansion or contraction of the lens unit due to the temperature change, the application unit causes the scanning unit to perform the change due to the temperature change. by amplitude when swinging the distal end of the light guide section is changed, is emitted from the tip of the light guide portion, a second change characteristic C the irradiation position of the illumination light in the subject is changed, the The drive is set to the predetermined frequency at which the illumination position of the illumination light does not change and becomes an offset value in the vicinity of the environmental temperature reached by the tip when the tip is inserted into the subject. The scanning endoscope apparatus according to claim 1, wherein a voltage is applied to the driving unit. The scanning endoscope cancels the first change characteristic V with the second change characteristic C at the environmental temperature in the scanning section and the lens section mounted on the scanning endoscope. The scanning endoscope apparatus according to claim 5, further comprising a storage unit that stores information of the predetermined frequency in the case of performing . The scanning unit has a resonance frequency when the amplitude reaches a peak as the amplitude of the light guide unit when the frequency of the driving voltage applied to the driving unit is changed, according to the temperature change due to a temperature rise. Has a lower frequency characteristic,
When the irradiation position of the illumination light on the subject by the lens section has a characteristic of changing to a peripheral position that expands the field of view according to the temperature rise, the application section applies driving to the driving section. As the voltage, applying the driving voltage set to a frequency higher than the resonance frequency before the temperature rise,
When the irradiation position of the illumination light on the subject by the lens section has a characteristic of changing to a position on the center side that reduces the visual field due to the temperature rise, the application section applies driving to the driving section. The scanning endoscope apparatus according to claim 1, wherein the driving voltage set at a frequency lower than the resonance frequency before the temperature rise is applied as a voltage. The drive unit swings in the two directions so as to draw a spiral trajectory at the tip of the light guide unit by applying two drive voltages respectively driving in two orthogonal directions,
At the reference first temperature T1, the irradiation position P1 of the illumination light on the subject at the drive voltage when the locus of the spiral shape becomes maximum, and the temperature change from the first temperature T1. At the second temperature T2, the amount of deviation from the irradiation position P2 of the illumination light on the subject at the drive voltage when the trajectory of the spiral shape becomes maximum is within a threshold range. The scanning endoscope apparatus according to claim 1, wherein the applying unit sets a frequency of the driving voltage applied to the driving unit to a specific frequency.   The storage unit stores a plurality of pieces of frequency information as the specific frequencies corresponding to the plurality of second temperatures T2 having different values of the temperature change from the first temperature T1. The scanning endoscope apparatus according to claim 8.   The scanning endoscope apparatus according to claim 9, wherein the storage unit further stores, as mapping data, information on a two-dimensional coordinate position that specifies the irradiation position P1 of the illumination light in the subject. .   The scanning endoscope apparatus according to claim 9, wherein the storage unit is provided in a scanning endoscope including the scanning unit and the lens unit.   The scanning endoscope apparatus according to claim 10, wherein the storage unit is provided in a scanning endoscope including the scanning unit and the lens unit.

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