JP7256051B2 - Endoscopes and endoscopic systems - Google Patents

Description

The present disclosure relates to endoscopes and endoscope systems that are inserted into a subject.

U.S. Patent No. 6,000,003 discloses an elongated endoscope shaft having an outer tube and an inner tube containing one or more illumination fiber optic bundles terminating in an exit face at the distal end of the endoscope shaft. A speculum is disclosed. In this endoscope, in the distal region of the endoscope shaft, an entrance optical element with a field direction that can be swiveled in at least one swivel plane is arranged and laterally illuminated by one or more illuminating fiber optic bundles. lighting is possible. At least a first illuminating fiber optic bundle illuminates a forward region of the distal end of the endoscope shaft at a viewing angle of 0 degrees. At least a second illumination fiber optic bundle illuminates another area with a side viewing angle or range of side viewing angles from 0 degrees to 90 degrees.

Japanese Patent Publication No. 2016-500538

When observing a subject inside a human body or the like with an endoscope over a wide angle of view of about 90 degrees as in Patent Document 1, it is important to be able to illuminate as uniformly as possible within the angle of view, thereby suppressing deterioration in image quality of captured images. is preferable from the viewpoint of However, in Patent Document 1, two types of illumination optical fiber bundles and an LED (Light Emission Diode) are arranged at the distal end of the endoscope. It has a configuration in which the optical fiber is bent. For this reason, there is a possibility that the image sensor will not be arranged at the tip because a sufficient space cannot be secured at the tip, and the image quality of the captured image will be degraded. In addition, in Patent Document 1, since lighting is performed by simply switching on and off lighting with two types of illumination fiber bundles and one LED, the technology of Patent Document 1 is used from the viewpoint of efficient illumination of a subject such as the human body. It is considered that there is room for improvement.

The present disclosure has been devised in view of the above-described conventional situation, efficiently illuminates and images a subject such as the human body while changing the field of view in a wide angle of view, and adjusts the lighting balance of light and dark to the subject. An object of the present invention is to provide an endoscope and an endoscope system that adaptively suppress deterioration of the image quality of a captured image based on the technique.

The present disclosure is an endoscope that is inserted into a subject, and includes an imaging unit that is arranged at a distal end of the endoscope and captures an image of the subject with a variable field of view within a predetermined angle of view; a plurality of illumination units arranged in a unit for illuminating an irradiation range in a plurality of different directions; According to the detected irradiation ranges of the plurality of lighting units included in the visual field direction of the imaging unit, among the lighting units included in the visual field direction of the imaging unit, the irradiation range within the visual field direction of the imaging unit. is the largest, and the light amount of the second illumination unit, which has a smaller irradiation range in the viewing direction of the imaging unit than the first illumination unit, is made smaller than that of the first illumination unit. To provide an endoscope which illuminates by changing the amount of light of a.

Further, the present disclosure is an endoscope system including an endoscope to be inserted into a subject and a control device for controlling the operation of the endoscope, wherein the endoscope an imaging unit arranged at the tip portion for imaging the subject with a variable field of view within a predetermined angle of view; a plurality of illumination units arranged at the tip portion for illuminating irradiation ranges in a plurality of different directions ; and a detection unit that detects a viewing direction of the imaging unit, wherein each of the plurality of illumination units covers an irradiation range of the plurality of illumination units included in the viewing direction of the imaging unit detected by the detection unit. According to the control of the control device according to the response, the amount of light of the first lighting unit having the largest irradiation range in the viewing direction of the imaging unit among the lighting units included in the viewing direction of the imaging unit is maximized. Provided is an endoscope system that illuminates by changing the light amount of illumination light so that the light amount of a second illumination section, which has a smaller irradiation range in the viewing direction of the imaging section than that of the first illumination section, is smaller than that of the first illumination section. .

According to the present disclosure, it is possible to efficiently illuminate and image a subject such as the inside of the human body while changing the field of view in a wide angle of view, and adaptively reduce image quality deterioration of the captured image based on the lighting balance of light and dark on the subject. can be suppressed.

1 is a diagram showing an overall configuration example of an endoscope system according to Embodiment 1; FIG. Perspective view showing a structural example of a camera head Side view showing a structural example of a camera head Block diagram showing an example of the internal configuration of the CCU and light source control device Circuit diagram showing a configuration example of a switching control circuit Diagram showing an example of the shape of a rotary encoder A diagram showing a parameter table showing an example of the detection state of the photoreflector and an example of the lighting balance ratio of the LED corresponding to the camera angle. FIG. 11 is a diagram showing an example of a correspondence relationship between the volume value of the lighting balance volume and the ratio of the lighting balance of the two selected LEDs; A diagram showing an example of the correspondence relationship between the volume value of the total light intensity volume and the ratio of the total light intensity Timing chart showing an example of light amount adjustment by PWM control A diagram explaining an example of illumination of two LEDs selected when the optical axis of the camera is oriented within the range of 0 to 7.5 degrees with respect to the axial direction of the scope. A diagram explaining an illumination example of two LEDs selected when the optical axis of the camera is oriented within the range of 7.5 degrees to 22.5 degrees with respect to the axial direction of the scope. A diagram explaining an example of illumination of two LEDs selected when the optical axis of the camera is oriented within the range of 22.5 degrees to 45 degrees with respect to the axial direction of the scope. A diagram explaining an example of illumination of two LEDs selected when the optical axis of the camera is oriented within the range of 45 degrees to 60 degrees with respect to the axial direction of the scope. A diagram explaining an example of illumination of two LEDs selected when the optical axis of the camera is oriented within the range of 60 to 75 degrees with respect to the axial direction of the scope. A diagram explaining an example of illumination of two LEDs selected when the optical axis of the camera is oriented within the range of 75 to 90 degrees with respect to the axial direction of the scope. 4 is a flow chart showing an example of an operation procedure of automatic illumination control of the endoscope system according to Embodiment 1; 4 is a flow chart showing an example of an operation procedure for adjusting the overall light intensity of the endoscope system according to Embodiment 1; 4 is a flowchart showing an example of an operation procedure for changing the camera angle of the endoscope system according to Embodiment 1; 4 is a flow chart showing an example of an operation procedure for illumination balance adjustment of the endoscope system according to Embodiment 1; FIG. 4 is a side view showing the structure of the camera head of the endoscope system according to the modified example of Embodiment 1;

Hereinafter, embodiments specifically disclosing the configuration and operation of an endoscope and an endoscope system according to the present disclosure will be described in detail with reference to the drawings as appropriate. However, more detailed description than necessary may be omitted. For example, detailed descriptions of well-known matters and redundant descriptions of substantially the same configurations may be omitted. This is to avoid unnecessary verbosity in the following description and to facilitate understanding by those skilled in the art. It should be noted that the accompanying drawings and the following description are provided for a thorough understanding of the present disclosure by those skilled in the art and are not intended to limit the claimed subject matter.

<Configuration of endoscope system>
FIG. 1 is a diagram showing an example of the overall configuration of an endoscope system 5 according to Embodiment 1. As shown in FIG. The endoscope system 5 includes an endoscope 10 , a light source control device 60 and a CCU (Camera Control Unit) 80 .

The endoscope 10 is a medical camera that can be handled with one hand by a user such as a doctor, as an example of a medical instrument. The endoscope 10 includes a scope 11 to be inserted into a subject such as the inside of a human body, and an operation section 12 for a user to operate the scope 11 at hand. The endoscope 10 may include a branch box 13 for branching each of the video signal line and the light amount adjustment signal line arranged to pass through the scope 11 . In FIG. 1, the branch box is abbreviated as "branch BOX".

The scope 11 is formed, for example, in a long, substantially cylindrical shape, and includes a flexible base-side soft section and a rigid distal-side hard section connected to the flexible section. A camera head 14 (see FIG. 2) is arranged inside the rigid portion. The proximal side indicates the side closer to the user of the endoscope 10, and the distal side indicates the side closer to the subject into which the endoscope 10 is inserted.

The camera head 14 has one camera 40 with a variable viewing direction and an illumination light source 30 . The illumination light source 30 includes three LEDs (Light Emitting Diodes) 31, 32, 33, for example.

The camera 40 is an imaging unit including a camera housing 41 (see FIG. 2) and an optical lens unit 42 (see FIG. 2). Hereinafter, in Embodiment 1, it is assumed that one camera 40 is arranged in the camera head 14 . However, although FIG. 2 shows an example in which one camera 40 is arranged in the camera head 14, a plurality of cameras (for example, two cameras) are arranged in the camera head 14 in the first embodiment. may be In this case, each camera can be moved independently to change the direction of view, or can be moved synchronously to change the direction of view. Also, the two cameras function as a stereo camera composed of, for example, a right-eye camera and a left-eye camera. The two cameras are synchronously moved together to capture images in the same imaging direction. It should be noted that, as described above, the two cameras can also operate separately and capture images in different imaging directions. In this case, the imaging range captured by the two cameras is relatively wider than the imaging range captured by the single camera 40 .

The camera 40, which is an example of an imaging unit, can change the viewing direction (an example of the camera angle) within a range of 0 to 90 degrees with respect to the axial direction of the scope 11, for example. A camera angle of 0 degrees is an angle at which the optical axis of the camera 40 coincides with the axial direction of the scope 11 . A camera angle of 90 degrees is an angle at which the optical axis of the camera 40 is perpendicular to the axial direction of the scope 11 .

Among the three LEDs 31, 32, and 33 as an example of the plurality of illumination units, the LED 31 is arranged so that the main irradiation direction is the axial direction of the scope 11, and illuminates at a predetermined (constant) irradiation angle. The LED 32 is arranged so that the main irradiation direction is a direction inclined downward by 45 degrees with respect to the axial direction of the scope 11, and illuminates at a predetermined (constant) irradiation angle. The LED 33 is arranged so that the main irradiation direction is the direction perpendicular to the axial direction of the scope 11 (downward by 90 degrees), and the LED 33 illuminates at a predetermined (constant) irradiation angle.

In the first embodiment, two of the three LEDs 31, 32, and 33 are lit at the same time, but it is not excluded that the three LEDs are lit at the same time, and only one LED is lit is not excluded.

The operating portion 12 is provided on the proximal side (base end side) of the flexible portion of the scope 11 . The operation unit 12 has a dial 25 that can be operated by the user. The dial 25 is rotatable around the rotation axis. When the dial 25 is operated, the operation unit 12 applies a pushing force or a pulling force to the support arm 142 (see FIG. 2) arranged inside the rigid portion of the scope 11 via a transmission member (for example, a wire or a belt). to move the support arm 142 in the front-rear direction (in other words, in the axial direction of the scope 11). By moving the support arm 142 in the front-rear direction, the camera 40 arranged on the distal end side of the scope 11 rotates within the range of 0 to 90 degrees around the rotation axis, thereby changing the camera angle. A rotating shaft of the dial 25 is provided with a rotary encoder 21 (see FIG. 6) for detecting the amount of rotation of the dial 25 (that is, the camera angle). Note that the operation unit 12 may have a slide switch or lever instead of the dial 25 .

The operation unit 12 has a dimming reset button 22 for resetting the lighting balance ratio of the lighting lights from the three LEDs 31, 32, and 33 to the default initial state. The operation unit 12 has a total light quantity volume 24 for varying the total light quantity of the illumination light emitted from the three LEDs 31, 32, and 33, and a variable ratio of the illumination balance of the illumination light from the three LEDs 31, 32, and 33. and a lighting balance volume 23 for The total light quantity indicates the overall light quantity (intensity) of the illumination light emitted from the LEDs. On the other hand, the illumination balance indicates the balance of the illumination light emitted from each of the two LEDs. The total light amount volume 24 and the illumination balance volume 23 are slide-type volumes (knobs) whose resistance values are changed by operating sliders. By operating the lighting balance volume 23, the user can change the ratio of the optimum lighting balance while watching a captured image displayed on a monitor (not shown), for example. Further, even after changing the lighting balance ratio, the user can press the dimming reset button 22 to return the lighting balance ratio to the default initial state.

FIG. 2 is a perspective view showing a structural example of the camera head 14. As shown in FIG. FIG. 3 is a side view showing a structural example of the camera head 14. As shown in FIG. The camera head 14 is arranged inside the rigid portion 111 . Camera head 14 includes transparent dome 35 , camera 40 and illumination source 30 . Inside the rigid portion 111 of the scope 11 , a plate-like partition member 131 having a step is provided to partition a part of the space inside the rigid portion 111 . 2 and 3 show the camera 40 and its drive mechanism.

Camera 40 has optical lens unit 42 and camera housing 41 . The optical lens unit 42 includes a lens barrel 42z that houses a focus lens and the like. The camera housing 41 includes an imaging device 43 arranged behind the optical lens unit 42 . The optical lens unit 42 has an angle of view of, for example, 90 degrees, receives light from a subject (target) within the angle of view, and forms an optical image on the imaging element 43 . The imaging device 43 converts the optical image formed on the imaging surface into an electrical signal and outputs the electrical signal as a video signal. The depth of field of the optical lens unit 42 is set to, for example, about 30 mm to 200 mm so that all organs observed inside the body are in focus when the scope 11 is inserted into the body.

The imaging device 43 is mounted on a long flexible substrate 150 arranged inside the scope 11 . The imaging device 43 is driven by drive signals transmitted from the CCU 80 via signal lines wired to the flexible substrate 150 , and also transmits captured video signals to the CCU 80 .

A rotary shaft is provided on the side surface of the camera housing 41 and is supported by a through hole formed in the side surface of the partition member 131 . The camera 40 is rotatable in directions of arrows e1 and e2 in the figure with respect to the partition member 131 about this rotation shaft (not shown). An engagement shaft 141 is provided on the side surface of the camera housing 41 to engage with the tip of a support arm 142 arranged inside the scope 11 . When the dial 25 of the operation unit 12 is operated by a user such as a doctor, the support arm 142 moves so as to be pushed out or pulled back.

When the support arm 142 is pushed in the direction of the arrow f1 in the figure, the engagement shaft 141 with which the tip of the support arm 142 engages is pushed forward, and the camera housing 41 moves in the direction of the arrow e1 in the figure around the rotation axis. direction. When the engagement shaft 141 is pushed out halfway, the camera housing 41 is tilted downward at an angle of 45 degrees, for example. When the engagement shaft 141 is pushed out by the maximum amount, the camera housing 41 faces directly downward, which is perpendicular to the axial direction of the scope 11 .

Further, when the support arm 142 is pulled back in the direction of the arrow f2 in the figure, the engagement shaft 141 with which the tip of the support arm 142 engages is pulled back, and the camera housing 41 rotates around the rotation axis. It rotates in the direction of e2. When the engagement shaft 141 is pulled back halfway, the camera housing 41 is tilted downward at an angle of 45 degrees, for example. When the amount of retraction of the engagement shaft 141 is maximum, the camera housing 41 faces the front, which is the axial direction of the scope 11 .

As the camera housing 41 rotates, the imaging element 43 arranged on the rear end side of the camera housing 41 also rotates at the same time. At this time, the long flexible substrate 150 on which the imaging element 43 is mounted is slightly bent and straightened.

Moreover, the distal end surface of the partition member 131 is formed on a surface perpendicular to the axial direction of the scope 11, a 45-degree slope, and a parallel surface. LEDs 31, 32, and 33 are arranged on the vertical plane, the 45-degree inclined plane, and the parallel plane, respectively. The three LEDs 31 , 32 , 33 irradiate the object (target) with illumination light through the transparent dome 35 .

FIG. 4 is a block diagram showing an internal configuration example of the CCU 80 and the light source control device 60. As shown in FIG. The CCU 80, which is an example of a control device, performs various types of image processing on image signals captured by the two cameras 40 and displays them on a monitor (not shown), as well as the illumination light source 30 (see FIG. 1). is controlled via a light source control device 60 as an example of a control device. The CCU 80 has a sensor control section 81 , a memory 82 , a CPU 83 and an illumination control section 84 .

The sensor control unit 81 drives the imaging element 43 of the camera 40 and inputs a video signal imaged by the imaging element 43 . The imaging device (an example of an image sensor) 43 is a solid-state imaging device such as a CCD (Charged-Coupled Device) or a CMOS (Complementary Metal-Oxide-Semiconductor). It forms an image, converts the formed optical image into an electrical signal, and outputs a video signal.

The memory 82 includes a primary storage device (eg, RAM (Random Access Memory), ROM (Read Only Memory)). The memory 82 may also include a secondary storage device (eg, HDD (Hard Disk Drive), SSD (Solid State Drive)) and a tertiary storage device (eg, optical disk, SD card). The memory 82 stores a parameter table Tb1 (an example of lighting control information) in which automatic lighting control parameters, which will be described later, are registered. The automatic lighting control parameter defines the correspondence relationship between the camera angle and the ratio of the light amount (that is, lighting balance) of the illumination light of each of the three LEDs 31, 32, and 33 (see FIG. 7).

The CPU 83 comprehensively controls the operation of each section within the CCU 80 . The CPU 83 realizes various functions by, for example, reading and executing a processing program held in the memory 82 by the CPU 83 . A processor such as an MPU (Micro processing Unit), a DSP (Digital Signal Processor), or a GPU (Graphical Processing Unit) may be used instead of the CPU 83 .

The illumination control unit 84 controls illumination operations by the three LEDs 31 , 32 , 33 . The lighting control section 84 has an automatic lighting balance switching control section 91 and a PWM control section 92 . Note that the illumination control unit 84 may also be configured using a processor (see above) including a CPU, like the CPU 83 .

The automatic lighting balance switching control unit 91 automatically controls the ratio of lighting balance by two of the three LEDs 31 , 32 , 33 . By selectively turning on two LEDs instead of all the three LEDs 31, 32, 33, it is possible to extend the life of the LEDs, suppress heat generation, and suppress an increase in power consumption. The automatic lighting balance switching control unit 91 can also automatically adjust the ratio of the lighting balance according to the reflection of illumination light by the subject (target) or the distance to the subject (target). Detection of the state of reflection of illumination light by the subject (target) or detection of the distance to the subject (target) may be realized by known techniques using, for example, one or more cameras.

When selectively lighting two of the three LEDs 31, 32, and 33, the PWM control unit 92 controls the on/off duty ratio of the drive signal (for example, drive current) supplied to each LED. Dim percentage of lighting balance.

The light source control device 60 turns on, off, or dims the three LEDs 31 , 32 , 33 according to the lighting balance ratio set by the CCU 80 . The light source control device 60 includes an A/D converter 61 , a switching control circuit 62 and LED drive circuits 63 and 64 . Note that the configuration of the light source control device 60 may be provided within the CCU 80 .

When the user rotates the dial 25 of the operation unit 12 to change the camera angle of the camera 40, the amount of rotation of the dial 25 is detected by the rotary encoder 21 supported on the rotary shaft. A rotary encoder 21 as an example of a detector outputs a 4-bit encoded value indicating the amount of rotation of the dial 25 . The details of the detection principle of the rotary encoder 21 will be described later.

A 4-bit encoded value is transmitted to the CPU 83 via the illumination control section 84 . Based on the parameter table Tb1 (see FIG. 7) stored in the memory 82, the CPU 83 reads the automatic lighting control parameters corresponding to the 4-bit encoded values and transfers them to the lighting control section 84. The lighting control section 84 generates a control signal based on the automatic lighting control parameters and outputs it to the switching control circuit 62 of the light source control device 60 .

The switching control circuit 62 selects two of the three LEDs 31, 32, and 33 according to the control signal from the illumination control section 84, and controls the lighting balance ratio of these selected two LEDs. Note that the lighting control based on the automatic lighting control parameters may be performed in synchronization with the video brightness information or the Vsync signal of the video signal.

Further, the resistance values manually adjusted by the total light amount volume 24 and the illumination balance volume 23 are converted into digital data by the A/D converter 61 . Digital data of this resistance value is transmitted to the illumination control section 84 . The illumination control unit 84 performs PWM (Pulse Width Modulation) control based on the digital data of the resistance value. The dimming reset button 22 is pressed when returning from the manually changed lighting balance mode (manual lighting mode) to the automatic lighting mode based on the automatic lighting control parameters.

FIG. 5 is a circuit diagram showing a configuration example of the switching control circuit 62. As shown in FIG. The automatic lighting balance switching control unit 91 inputs the automatic lighting control parameters registered in the parameter table Tb1 stored in the memory 82, and the volume value indicated by the lighting balance volume 23 or the pressing of the dimming reset button 22. input signal. The PWM control unit 92 inputs the volume value indicated by the total light quantity volume 24 .

A switching control circuit 62 of the light source control device 60 has a selector circuit 72 , LED drive circuits 63 and 64 , and analog switches (SW) 75 and 76 . The selector circuit 72 selects the analog SW 75 or the analog SW 76 according to the signal from the automatic lighting balance switching control section 91 . The analog switch 75, when selected by the selector circuit 72, conducts between the LED drive circuit 63 and the anode terminal of the LED 31. FIG. In addition, the analog switch 76, when selected by the selector circuit 72, conducts between the LED drive circuit 63 and the anode terminal of the LED 32. FIG.

The LED drive circuit 63 supplies an LED drive current to the LED 31 when the analog switch 75 is turned on. The LED drive circuit 63 supplies an LED drive current to the LED 32 when the analog switch 76 is turned on. Also, the LED drive circuit 64 supplies an LED drive current to the LED 33 in accordance with a signal from the automatic lighting balance switching control section 91 .

In this switching control circuit 62, one of the three LEDs 31, 32, 33 is selected according to the automatic lighting control parameters and according to the volume value of the lighting balance volume 23 and the volume value of the total light quantity volume 24 operated by the user. The light intensity of the two LEDs is adjusted.

Further, when the user presses the dimming reset button 22, the light amounts of two of the three LEDs 31, 32, and 33 are restored to the values based on the automatic lighting control parameters. Of the three LEDs 31, 32, and 33, the LED 32, which is arranged in the middle position, lights up regardless of the camera angle of 0 degrees to 90 degrees.

The switching control circuit 62 normally performs lighting control of the three LEDs 31, 32, 33 according to the proportion of the lighting balance based on the automatic lighting control parameters. When the user operates the illumination balance volume 23, priority is given to performing illumination control according to the ratio of the illumination balance based on the volume value of the illumination balance volume 23. FIG. When the user presses the dimming reset button 22, the switching control circuit 62 preferentially returns to the lighting control by the balance ratio based on the automatic lighting control parameters.

Further, when the user operates the total light intensity volume 24, the switching control circuit 62 performs PWM control regardless of the light intensity control based on the automatic lighting control parameters, and supplies the LED driving currents to the LEDs 31, 32, and 33 respectively. can be varied in the range of 0% to 100% of the maximum current value. For example, when the overall light intensity is set to 80% of the maximum current value by operating the total light intensity volume 24, 80% of this maximum current value corresponds to 100% of the PWM ratio.

FIG. 6 is a diagram showing an example of the shape of the rotary encoder 21. As shown in FIG. The rotary encoder 21 has a quarter disc 211 and a photoreflector 212 . The 1/4 disc 211 is pivotally supported by the rotating shaft of the dial 25 passing through a hole 211z formed near the center of the sector. When the rotary shaft of the dial 25 rotates in the range of 0° to 90°, the quarter disk 211 also rotates together with the rotary shaft. The quarter disc 211 is formed with a plurality of slits 211a, 211b, 211c, and 211d which are concentric openings formed around the hole 211z.

Also, the photoreflector 212 is arranged to face the surface of the quarter disk 211 . The photoreflector 212 has four photoreflectors FR1, FR2, FR3 and FR4. The four photoreflectors FR1, FR2, FR3 and FR4 each have a set of light emitting elements and photosensors LS1, LS2, LS3 and LS4.

Each light-emitting element emits projection light toward positions P1, P2, P3, and P4 in the axial radial direction of the quarter disc 211 . The four photosensors LS1, LS2, LS3 and LS4 respectively receive reflected light reflected at positions P1, P2, P3 and P4. When slits are formed at positions P1, P2, P3, and P4 of the quarter disc 211, projected light from the light emitting element is not reflected. The photosensor outputs an H level signal when it receives the light reflected by the surface of the quarter disc 211 . The photosensor outputs an L level signal when it does not receive reflected light.

For example, in FIG. 6, since the slit 211d is formed at the position P3 of the quarter disc 211, the projection light from the light emitting element passes through the slit 211d and is not reflected at the position P3. Since the photosensor LS3 does not receive the reflected light, it outputs an L (Low) level signal. Other photosensors LS1, LS2, and LS4 receive reflected light reflected at positions P1, P2, and P4, respectively, and output H (High) level signals. The H level signal and L level signal output from photosensors LS1, LS2, LS2 and LS4 are output as 4-bit encoded values representing the detection state of photoreflector 212. FIG.

FIG. 7 is a diagram showing a parameter table Tb1 showing detection state examples of the photoreflector 212 and lighting balance ratio examples of the LEDs corresponding to camera angles. Angle no. 1 to No. Each of the 12 is assigned each time there is a change in the presence or absence of slits in the rotation direction of the quarter disc 211 . Here, for example, the angle No. is set in units of 7.5 degrees. changes.

For example, the state of the rotary encoder 21 shown in FIG. 12. Angle no. 12, the camera angle is between 82.5 degrees and 90 degrees. A 4-bit encoded value indicating the photoreflector detection state is "1, 0, 1, 1". The lighting balance ratios of the LEDs 31, 32 and 33 are 0%, 25% and 100%, respectively. Also, the angle no. 1, the camera angle is between 0 and 7.5 degrees. The 4-bit encoded value is "0, 1, 1, 1". The lighting balance ratios of the three LEDs 31, 32, and 33 are 100%, 25%, and 0%, respectively.

As an example, when dimming each of the three LEDs 31, 32, and 33, the automatic lighting balance switching control unit 91 sets the total value (sum) of the balance ratios to a default value (for example, 125%) in 32 steps. to change the balance ratio. The 32-step number is merely an example. At this time, the automatic lighting balance switching control unit 91 can also adjust the total light amount while maintaining the balance ratio of the two LEDs.

FIG. 8 is a diagram showing the correspondence relationship between the volume value of the illumination balance volume 23 and the illumination balance ratio of the selected two LEDs. The lighting balance ratio of the LEDs corresponds to the PWM ratio (duty ratio in PWM control). Combinations of the two selected LEDs include a combination of the LEDs 31 and 32 and a combination of the LEDs 32 and 33 . For example, angle no. 1 to angle No. Each of 7 corresponds to a combination of LED31 and LED32. Angle no. 8 to angle No. Each of 12 corresponds to the combination of LED32 and LED33. Angle no. 1 to angle No. In any of the 12 cases, the total value of the lighting balance percentage of the two LEDs is 125%. For example, angle no. In the case of 3, the lighting balance percentage for LED 31 is 75% and the lighting balance percentage for LED 32 is 50%.

FIG. 9 is a diagram showing an example of the correspondence relationship between the volume value of the total light amount volume 24 and the ratio of the total light amount. The total light amount volume 24 can adjust the total light amount in 32 steps, for example. The resistance value of the total light amount volume 24 is divided into 32 steps. When the dividing number of the resistance value of the total light amount volume 24 is 0, the ratio of the total light amount is 0%. In this case, the LED drive current by PWM control becomes the minimum value. When the dividing number of the resistance value of the total light amount volume 24 is 32, the ratio of the total light amount is 100%. In this case, the LED drive current by PWM control becomes the maximum value.

FIG. 10 is a timing chart showing an example of light amount adjustment by PWM control. During the exposure time included in the line period of the imaging element 43, the LED is lit by PWM control. If the PWM ratio is a small value, the LED drive current will be less and the illumination will be darker. If the PWM ratio is a large value, the LED drive current will be high and the illumination will be bright.

Next, an example of illumination in the case of controlling illumination with an automatic illumination control pattern with respect to the camera angle will be described. Illumination is performed using two of the three LEDs 31 , 32 , 33 . The maximum light amount is a light amount corresponding to 125%, which is the sum of the balance ratios of the two LEDs, in which the illumination light emitted by the two LEDs overlaps.

11A and 11B are diagrams for explaining an illumination example of two LEDs selected when the optical axis of the camera 40 points in a direction within the range of 0 to 7.5 degrees with respect to the axial direction of the scope 11. FIG. The axial direction of the scope 11 is the horizontal direction in the figure. The irradiation angles of the three LEDs 31, 32, 33 are the same. Angle no. In 1, the proportion of lighting balance for LED 31 is 100%. The proportion of illumination balance for the LEDs 32 is 25%. The lighting balance ratio of the LED 33 is 0%. That is, it is selectively and efficiently illuminated from the LEDs 31 and 32 that match the illumination in the direction of the optical axis of the camera 40 (in other words, the depth of field of the target tg), and the illumination from the LED 33 is omitted. In this case, the LED 31 mainly illuminates the target tg (for example, the wall surface of the organ) brightly from the front. The imaging device 43 captures a front image of the brightly illuminated target tg. The area where the irradiation range irradiated by the LED 31 and the irradiation range irradiated by the LED 32 overlap corresponds to a balance ratio of 125% and is illuminated more brightly.

FIG. 12 is a diagram for explaining an illumination example of two LEDs selected when the optical axis of the camera 40 is oriented within the range of 7.5 degrees to 22.5 degrees with respect to the axial direction of the scope 11. FIG. be. Angle no. 2 or angle no. In the case of 3, the proportion of illumination balance for LED 31 is 75%. The lighting balance percentage of the LEDs 32 is 50%. The lighting balance ratio of the LED 33 is 0%. That is, it is selectively and efficiently illuminated from the LEDs 31 and 32 that match the illumination in the direction of the optical axis of the camera 40 (in other words, the depth of field of the target tg), and the illumination from the LED 33 is omitted. In this case, both the LEDs 31 and 32 mainly illuminate the target tg slightly obliquely (slightly obliquely downward from the axial direction of the scope 11). The imaging element 43 captures a slightly oblique image of the brightly illuminated target tg. The area where the irradiation range irradiated by the LED 31 and the irradiation range irradiated by the LED 32 overlap is angle No. Similar to 1, more brightly illuminated.

13A and 13B are diagrams for explaining an illumination example of two LEDs selected when the optical axis of the camera 40 points in a direction within the range of 22.5 degrees to 45 degrees with respect to the axial direction of the scope 11. FIG. Angle no. 4, angle no. 5 or angle No. In the case of 6, the proportion of illumination balance for LED 31 is 25%. The lighting balance percentage of the LEDs 32 is 100%. The lighting balance ratio of the LED 33 is 0%. That is, it is selectively and efficiently illuminated from the LEDs 31 and 32 that match the illumination in the direction of the optical axis of the camera 40 (in other words, the depth of field of the target tg), and the illumination from the LED 33 is omitted. In this case, the LED 32 mainly illuminates the target tg in an oblique direction (diagonally downward from the axial direction of the scope 11). The imaging device 43 captures an oblique image of the brightly illuminated target tg. The area where the irradiation range irradiated by the LED 31 and the irradiation range irradiated by the LED 32 overlap is angle No. As in case 1, it is illuminated more brightly.

14A and 14B are diagrams for explaining an illumination example of two LEDs selected when the optical axis of the camera 40 points in a direction within a range of 45 degrees to 60 degrees with respect to the axial direction of the scope 11. FIG. Angle no. 7 or angle No. In the case of 8, the lighting balance percentage of the LED 31 is 0%. The lighting balance percentage of the LEDs 32 is 100%. The lighting balance ratio of the LEDs 33 is 25%. That is, it is selectively and efficiently illuminated from the LEDs 32 and 33 that match the illumination in the direction of the optical axis of the camera 40 (in other words, the depth of field of the target tg), and the illumination from the LED 31 is omitted. The LED 32 mainly illuminates the target tg more obliquely (more obliquely downward from the axial direction of the scope 11). The imaging device 43 captures a more oblique image of the brightly illuminated target tg. In this case, the amount of illumination light is large above the optical axis of the camera 40, and the far field is illuminated brightly. The amount of illumination light is small on the lower side with respect to the optical axis of the camera 40, and the near field is illuminated darkly. In addition, the area|region where the irradiation range which LED32 irradiates and the irradiation range which LED32 irradiates overlaps is illuminated more brightly.

15A and 15B are diagrams for explaining an illumination example of two LEDs selected when the optical axis of the camera 40 points in a direction within the range of 60 to 75 degrees with respect to the axial direction of the scope 11. FIG. Angle no. 9 or angle no. In the case of 10, the proportion of illumination balance for LED 31 is 0%. The lighting balance percentage of the LEDs 32 is 50%. The lighting balance percentage of the LEDs 33 is 75%. That is, it is selectively and efficiently illuminated from the LEDs 32 and 33 that match the illumination in the direction of the optical axis of the camera 40 (in other words, the depth of field of the target tg), and the illumination from the LED 31 is omitted. The LEDs 32 and 33 also mainly brightly illuminate the target tg obliquely downward. The imaging device 43 captures an obliquely downward image of the brightly illuminated target tg. The area where the irradiation range irradiated by the LED 32 and the irradiation range irradiated by the LED 33 overlap is angle No. 7 or angle No. As with 8, it is illuminated more brightly.

FIG. 16 is a diagram for explaining an illumination example of two LEDs selected when the optical axis of the camera 40 faces in a direction within the range of 75 to 90 degrees with respect to the axial direction of the scope. Angle no. 11 or angle no. In the case of 12, the lighting balance percentage of LED 31 is 0%. The proportion of illumination balance for the LEDs 32 is 25%. The lighting balance ratio of the LEDs 33 is 100%. That is, it is selectively and efficiently illuminated from the LEDs 32 and 33 that match the illumination in the direction of the optical axis of the camera 40 (in other words, the depth of field of the target tg), and the illumination from the LED 31 is omitted. The LED 33 mainly brightly illuminates the target tg directly downward. The imaging device 43 captures an image of the brightly illuminated target tg directly below. The area where the irradiation range irradiated by the LED 32 and the irradiation range irradiated by the LED 33 overlap is angle No. 7 or angle No. As with 8, it is illuminated more brightly.

In the lighting example described above, the lighting balance ratio of the LEDs 31, 32, and 33 was set according to the camera angle. may be set.

<Operation of the endoscope system>
Next, the operation of the endoscope system 5 according to Embodiment 1 will be described in detail. When the user turns on the CCU 80, the endoscope system 5 is activated.

(lighting control)
FIG. 17 is a flow chart showing an operation procedure example of automatic lighting control of the endoscope system 5 according to the first embodiment.

In FIG. 17, the CPU 83 of the CCU 80 instructs the sensor control section 81 and the lighting control section 84 to initialize the camera 40 (S1). Each of the sensor control unit 81 and the lighting control unit 84 causes the camera 40 to transition to the initial state according to instructions from the CPU 83 . In the initial state of the camera 40, for example, the sensor control unit 81 puts the imaging device 43 into a non-exposure state. Also, the lighting control unit 84 turns off the three LEDs 31 , 32 , 33 .

The lighting control unit 84 starts lighting control (S2). The illumination control unit 84 reads the current values (4-bit encoded values) of the four photosensors LS1, LS2, LS3, and LS4 included in the rotary encoder 21 (S3).

The automatic lighting balance switching control unit 91 refers to the parameter table Tb1 (see FIG. 7) registered in the memory 82 and reads automatic lighting control parameters corresponding to camera angles indicated by 4-bit encoded values (S4). Automatic lighting control parameters include LED selection and lighting balance percentage for each LED. The automatic lighting balance switching control unit 91 stores the current (initial) automatic lighting control parameters in the memory 82 (S5). By storing the initial automatic lighting control parameters obtained from the camera angle in the memory 82 , when the user presses the dimming reset button 22 , the automatic lighting balance switching control unit 91 changes the parameters stored in the memory 82 . Initial automatic lighting control parameters can be read from memory 82 and used.

The automatic lighting balance switching control unit 91 reads the data of the camera angle and the balance ratio changed by manual operation, which are stored in the memory 82 (S6).

The automatic lighting balance switching control unit 91 selects the LED corresponding to the camera angle changed by manual operation and sets the PWM ratio (S7). The LED selection is a combination of LED31 and LED32 or LED32 and LED33. The PWM control unit 92 sets the PWM ratio on the LED drive circuit 63 side and the PWM ratio on the LED drive circuit 64 side based on the selected combination of LEDs.

The PWM control unit 92 reads the total light quantity data stored in the memory 82 (S8). The PWM control unit 92 calculates the ratio of the total light intensity on the LED drive circuit 63 side according to Equation (1) based on the PWM ratio and the total light intensity data on the LED drive circuit 63 side (S9).

Ratio of total light intensity on the LED drive circuit 63 side = PWM ratio on the LED drive circuit 63 side x total light intensity ...... (Formula 1)

Similarly, the PWM control unit 92 calculates the ratio of the total light intensity on the LED drive circuit 64 side according to Equation (2) based on the PWM ratio and the total light intensity data on the LED drive circuit 64 side.

Ratio of total light intensity on LED drive circuit 64 side = PWM ratio on LED drive circuit 64 side × total light intensity (Formula 2)

The switching control circuit 62 performs lighting control for the selected combination of LEDs according to the control signal from the PWM control section 92 (S10). The LEDs 31 and 32 (or the LEDs 32 and 33) are lit according to lighting control based on PWM control. After that, the lighting control unit 84 returns to step S6 and performs the same processing until the CCU 80 is turned off.

(Overall light intensity adjustment)
Immediately after the endoscope system 5 is started, each of the LEDs 31 and 32 illuminates with a light amount corresponding to the volume value of the total light amount volume stored in the memory 82 when the CCU 80 is powered on. The user can manually adjust the light amount of the LEDs 31 to 32 with the total light amount volume 24 . Here, it is assumed that the user operates the total light amount volume 24 to adjust the total light amount.

FIG. 18 is a flow chart showing an example of an operation procedure for adjusting the total light amount of the endoscope system 5 according to Embodiment 1. FIG.

In FIG. 18, when the total light amount volume 24 is operated, the light source control device 60 acquires the value of the total light amount volume 24 from the operation section 12 (S11). The A/D converter 61 performs analog-to-digital conversion on the volume value of the total light quantity volume 24 to obtain total light quantity data (S12). The illumination control unit 84 determines whether or not the volume value of the total light quantity volume 24 has changed (S13). When the volume value of the total light amount volume 24 changes, the illumination control section 84 externally interrupts the CPU 83 and sends the total light amount data to the CPU 83 . The CPU 83 stores the total light quantity data in the memory 82 . After that, the illumination control unit 84 returns to the process of step S11 and repeats the same process. On the other hand, if the value of the total light amount volume 24 has not changed, the lighting control unit 84 returns to the process of step S11 and repeats the same process. Although the illumination control section 84 performs an external interruption to the CPU 83 here, the CPU 83 may perform polling processing and read the total light amount data from the illumination control section 84 .

(change camera angle)
When the user rotates the dial 25 of the operation unit 12 to change the camera angle, the rotary encoder 21 rotates by the same rotation amount as the dial 25 . When the amount of rotation of the rotary encoder 21 detected by the four photoreflectors FR1, FR2, FR3, and FR4 exceeds a predetermined amount of rotation, the 4-bit encoded value indicating the camera angle changes. The illumination control unit 84 issues an external interrupt to the CPU 83 and transmits a 4-bit encoded value to the CPU 83 . The CPU 83 stores the 4-bit encoded value in the memory 82 .

FIG. 19 is a flow chart showing an example of an operation procedure for changing the camera angle of the endoscope system 5 according to the first embodiment.

In FIG. 19, the illumination control unit 84 detects the states of the four photoreflectors FR1, FR2, FR3, and FR4 of the rotary encoder 21, and determines whether or not the 4-bit encoded value has changed (S31). If the 4-bit encoded value has not changed, the lighting control unit 84 repeats the process of step S31. On the other hand, if the 4-bit encoded value has changed, the illumination control unit 84 reads the 4-bit encoded value (S32).

The lighting control unit 84 refers to the parameter table Tb1 registered in the memory 82, and selects the automatic lighting control parameters (LED combination and each PWM ratio) corresponding to the 4-bit encoded value (S33). The lighting control unit 84 issues an external interrupt to the CPU 83 and transmits a 4-bit encoded value and automatic lighting control parameters (S34). CPU 83 stores the 4-bit encoded value and the automatic lighting control parameter in memory 82 . After that, the illumination control unit 84 returns to the process of step S31 and repeats the same process. Although the illumination control unit 84 externally interrupts the CPU 83 here, the CPU 83 may perform polling processing to read the 4-bit encoded value and the automatic illumination control parameter from the illumination control unit 84 .

(lighting balance adjustment)
When an illumination light source is provided at the tip of the scope of an endoscope, the illumination light is reflected by a target (for example, the wall surface of an organ) close to the tip, causing a flare phenomenon within a part of the camera's angle of view. may cause The flare phenomenon varies depending on the distance and angle from the camera to the target and the material of the target. Also, the illumination varies between when the target is close to the tip of the scope and when it is far away from the tip of the scope.

In particular, in the case of an endoscope inserted into the body, etc., the depth of field is required to be approximately 30 mm to 200 mm, and all organs to be observed within the body must be in focus. In other words, the illuminating light must reach a distance of about 200 mm inside the body. However, since the illumination light source has a wide irradiation angle of approximately 90°, it is not possible to uniformly irradiate the entire irradiation range with the illumination light.

Also, when the camera 40 is inserted into the body, there are many cases where the camera 40 is inserted from the upper side of the body. Therefore, the camera 40 is far from the target on the upper side, and the camera 40 is close to the target on the lower side. As a result, the illumination balance is biased.

The user can adjust the vertical lighting balance by manually varying the lighting balance volume 23 of the operation unit 12 . When manually adjusting the lighting balance, the lighting control transitions from automatic lighting control mode to manual mode. The value of the lighting balance volume 23 is analog-to-digital converted by the A/D converter 61 . The analog-to-digital converted lighting balance data is input to the CPU 83 through polling processing of the CPU 83 or an external interrupt to the CPU 83 . The CPU 83 stores the lighting balance data in the memory 82 .

The lighting control unit 84 transitions from the automatic lighting control mode based on the automatic lighting control parameters to the manual mode based on the value of the lighting balance volume 23 to vary the balance ratio. Here, the lighting balance volume 23 is a sliding volume and adjusts the balance ratio of the two LEDs.

Also, the amount of heat generated by the illumination light source is limited. For example, if the sum of the balance ratios of the two LEDs is 125%, setting the illumination balance volume 23 to the center position results in the balance ratios of the two LEDs being 75% and 50%. Also, when the illumination balance volume 23 is set to the upper limit position and the lower limit position, the balance ratio of the two LEDs becomes 125% at maximum by addition.

Further, when the user moves the camera head 14 to the next position, there are cases where the user wants to change the balance ratio and cases where the user does not want to change the balance ratio. A dimming reset button 22 is provided on the operation unit 12 . By pressing the dimming reset button 22, the user can return from the manual mode to the automatic lighting control mode. When returning to the automatic lighting control mode, the lighting control unit 84 can return to the lighting state corresponding to each value of the camera angle (encoded value of 4 bits), the total light amount volume 24 and the lighting balance volume 23 .

20 is a flowchart illustrating an example of an operation procedure for lighting balance adjustment according to Embodiment 1. FIG.

In FIG. 20, the automatic lighting balance switching control unit 91 inputs the value of the lighting balance volume 23 and determines whether or not the value of the lighting balance volume 23 has been changed (S41). If the value of the lighting balance volume 23 has not been changed, the automatic lighting balance switching control section 91 repeats the process of step S41.

When the value of the illumination balance volume 23 is changed in step S41, the A/D converter 61 analog-to-digital converts the value of the illumination balance volume 23 to obtain illumination balance data (S42). The illumination control unit 84 performs an external interruption to the CPU 83 and transmits illumination balance data (S43). The CPU 83 stores the lighting balance data in the memory 82 . Although the illumination control unit 84 performs an external interrupt to the CPU 83 here, the CPU 83 may perform polling processing to read the illumination balance data from the illumination control unit 84 .

The lighting control unit 84 reads the lighting balance data stored in the memory 82 (S44). The automatic lighting balance switching control section 91 turns off the automatic lighting control mode (S45). The PWM control unit 92 sets the PWM ratio based on the lighting balance data (S46). After that, the illumination control unit 84 returns to the process of step S41.

As described above, in the endoscope system 5 according to Embodiment 1, the endoscope 10 has the dimming ratio (illumination Since the lighting is performed by changing the balance ratio), heat generation due to LED light emission can be suppressed. Therefore, changing the camera angle does not cause the target to become hot. In addition, the endoscope 10 can turn off one LED by not illuminating an area (outside the field of view) exceeding the imaging range of the camera 40, and can lower the dimming ratio of the two LEDs. It is possible to extend the life of the LED. In addition, the endoscope 10 is likely to cause halation (a phenomenon in which the periphery of a portion hit by strong light becomes white and blurry) and stray light (optical instrument unwanted light scattering in the interior) can be eliminated. In addition, the endoscope 10 can illuminate the far portion strongly, and can prevent the far portion from becoming extremely dark. Therefore, the endoscope 10 can suppress the deterioration of the image captured by the camera 40 and improve the image quality of the captured image.

As described above, in the endoscope system 5 according to Embodiment 1, the endoscope 10 is inserted into the body (inside the object) such as a human body. The endoscope 10 is arranged at the distal end of the scope 11, and has a camera 40 for imaging the target tg with a variable field of view within a predetermined angle of view. Three LEDs 31, 32, 33 are provided for illuminating irradiation ranges in a plurality of different directions as a reference. Each of the three LEDs 31 , 32 , 33 illuminates the corresponding illumination range by changing the amount of illumination light according to the viewing direction of the camera 40 .

Thus, in the endoscope system 5, the endoscope 10 can efficiently illuminate and image the inside of the body such as a human body while changing the field of view within a wide angle of view. Therefore, the endoscope 10 can adaptively suppress image quality deterioration of the captured image based on the lighting balance of light and dark on the subject.

Moreover, the endoscope 10 further includes a rotary encoder 21 that detects a camera angle, which is the viewing direction of the camera 40 . Two of the three LEDs 31, 32, and 33 change the balance ratio of the amount of illumination light to the corresponding illumination range according to the camera angle detection result. As a result, the endoscope 10 can accurately detect the camera angle and illuminate the target with the optimum amount of light for the camera angle.

The endoscope 10 also includes an operation unit 12 that is arranged on the proximal side of the scope 11 (in other words, on the proximal side of the endoscope 10) and receives operations by the user. The camera 40 changes the viewing direction according to the user's operation. As a result, the user can easily change the field of view of the camera by manual operation.

Also, the illumination balance volume 23 of the operation unit 12 accepts an adjustment operation of the balance ratio of the illumination light from each of the two LEDs to the target tg. Thereby, the user can easily adjust the balance ratio by hand operation.

Further, the total light amount volume 24 of the operation unit 12 receives an operation for adjusting the total light amount based on the illumination light from each of the two LEDs to the target tg. As a result, the user can easily adjust the total amount of light by manual operation.

The endoscope system 5 also includes an endoscope 10 that is inserted into a body such as a human body, and a CCU 80 that controls the operation of the endoscope 10 . The endoscope 10 is inserted into a body (inside a subject) such as a human body. The endoscope 10 is arranged at the distal end of the scope 11, and has a camera 40 for imaging the target tg with a variable field of view within a predetermined angle of view. Three LEDs 31, 32, 33 are provided for illuminating irradiation ranges in a plurality of different directions as a reference. Each of the three LEDs 31 , 32 , 33 illuminates the corresponding irradiation range by changing the amount of illumination light under the control of the CCU 80 according to the viewing direction of the camera 40 .

As a result, the endoscope system 5 can efficiently illuminate and image the inside of the body such as the human body with the endoscope 10 while changing the field of view within a wide field angle. Therefore, the endoscope system 5 can adaptively suppress image quality deterioration of the captured image based on the lighting balance of light and dark on the subject.

Moreover, the endoscope 10 further includes a rotary encoder 21 that detects a camera angle, which is the viewing direction of the camera 40 . The CCU 80 holds in the memory 82 a parameter table Tb1 in which are registered automatic lighting control parameters that define the relationship between the camera angle and the lighting balance ratio of the amount of illumination light of each of the three LEDs 31 , 32 , 33 . The CCU 80 instructs two of the three LEDs 31, 32, and 33 to change the balance ratio of the amount of illumination light to the corresponding irradiation range based on the camera angle detection result and the parameter table Tb1. do. Thereby, the CCU 80 can accurately detect the camera angle of the endoscope 10 . The endoscope 10 can illuminate the target with the optimal amount of light for the camera angle.

Also, the illumination balance volume 23 of the operation unit 12 accepts an adjustment operation of the balance ratio of the illumination light from each of the two LEDs to the target tg. The automatic illumination balance switching control unit 91 of the CCU 80 changes the balance ratio of the amount of illumination light to the corresponding irradiation range for each of the two LEDs according to the adjustment operation of the balance ratio of the illumination light to the target tg. Indicates a change from one value to another. Thereby, the user can easily adjust the balance ratio by hand operation.

Further, the total light amount volume 24 of the operation unit 12 receives an operation for adjusting the total light amount based on the illumination light from each of the two LEDs to the target tg. The automatic illumination balance switching control unit 91 of the CCU 80 changes the intensity of the illumination light intensity to the corresponding irradiation range for each of the two LEDs according to the adjustment operation of the overall light intensity based on the illumination light to the target tg. Indicates a change from one value to another. As a result, the user can easily adjust the total amount of light by manual operation.

The endoscope 10 also includes three LEDs 31 , 32 , 33 . The CCU 80 adjusts the irradiation range corresponding to each of the two LEDs 31, 32, and 33 so that the sum of the balance ratios of the illumination light amounts of the two LEDs is 125% (predetermined value). command to change the balance ratio of the amount of illumination light. As a result, the endoscope 10 can appropriately change the amount of light in accordance with the target tg and capture an image with high image quality.

The operation unit 12 also has a dimming reset button 22 (an example of a reset button related to the balance ratio) that resets the balance ratio of the amount of illumination light from each of the two LEDs to the target tg to the initial state. The automatic illumination balance switching control unit 91 of the CCU 80 determines the balance ratio of the amount of illumination light from each of the two LEDs to the target tg in response to the pressing operation of the dimming reset button 22, based on the detection result of the camera angle and the parameter table. The control is returned to the control based on the automatic lighting control parameters registered in Tb1. As a result, the user can easily restore the lighting balance by manual operation.

(Modification)
In the above-described embodiment, the illumination is performed using the three LEDs 31, 32, and 33 as illumination light sources, but a single light source may be used for illumination. That is, the plurality of lighting units may be realized by a plurality of LEDs or the like, or may be realized by a single light source. The single light source here has a plurality of light emitting surfaces arranged at different angles with respect to the axial direction of the scope 11 of the endoscope 10, as will be described later. Moreover, the single light source here has a plurality of irradiation areas, and the light amount of the irradiation light can be individually adjusted for these plurality of irradiation areas. By configuring the single light source in this manner, it can operate as a plurality of illumination units. Details are provided below.

FIG. 21 is a side view showing the structure of the camera head 14A of the endoscope system 5 according to the modified example of the first embodiment. Camera head 14A has a single light source. The same reference numerals are given to the same members as in the first embodiment, and the description thereof is omitted.

The distal end face of the partition member 131 is formed on a plane perpendicular to the axial direction of the scope 11, a 45-degree slope, and a plane parallel thereto. A sheet light source 230 (an example of a plurality of illumination units), which is a single light source, is provided on the tip surface of the partition member 131 so as to cover the vertical plane, the 45-degree slant plane, and the parallel plane. It is attached so as to be in close contact with each surface of the surface. Here, the portions of the sheet light source 230 attached to the vertical plane, the 45-degree inclined plane, and the parallel plane are respectively referred to as a partial sheet light source 230a, a partial sheet light source 230b, and a partial sheet light source 230c.

As an example, the sheet light source 230 has a surface emitting LED sheet 231 and a liquid crystal shutter 232 laminated on this surface. The LED sheet 231 arranges LEDs on the side surface of a light guide plate made of, for example, fluorescent acrylic, and diffuses the illumination light from the LEDs while guiding the light to the light guide plate, thereby irradiating the diffused illumination light from the front of the light guide plate. The liquid crystal shutter 232 transmits or shields the diffused illumination light emitted from the front of the LED sheet 231 in units of predetermined pixel groups, so that each tip surface of the partition member 131 (vertical surface, 45-degree inclined surface and parallel surface). ) to change the balance ratio of the diffuse illumination light emitted from the

For example, the liquid crystal shutter 232 is driven so that the transmittance of the sheet light source 230a is 100% and the transmittance of the sheet light source 230b is 25%. Angle no. An illumination pattern similar to that of 1 is realized.

Here, the liquid crystal shutter is used to change the lighting balance ratio of the LED sheet, but a sheet-like liquid lens may be used to change the lighting balance ratio of the LED sheet. In this case, a surface-emitting LED sheet and a sheet-like liquid lens laminated on this surface are used as the sheet light source. A liquid lens seals a conductive aqueous solution and a non-conductive oil in a frame, and changes the interface between the water and the oil by applying a voltage to the water.

When a sheet-shaped liquid lens is used, for example, when increasing the balance ratio of a part of the sheet light source 230b attached to the 45-degree slope, the sheet-shaped liquid lens in the portion corresponding to the 45-degree slope has a liquid refractive index of By changing , it becomes a convex lens. As a result, the diffused illumination light emitted from the LED sheet 231 can be condensed in the oblique 45-degree direction, and the balance ratio in the oblique 45-degree direction is increased. When the balance ratio of the partial sheet light source 230b attached to the 45-degree slope is reduced, the sheet-like liquid lens in the portion corresponding to the 45-degree slope becomes a concave lens by changing the refractive index of the liquid. As a result, the diffused illumination light emitted from the LED sheet 231 can be diffused from the oblique 45-degree direction, and the balance ratio in the oblique 45-degree direction is reduced.

In this manner, sheet-like liquid lenses are individually used for each of the vertical surface, the 45-degree inclined surface, and the parallel surface, which are the tip surfaces of the partition member 131, so that the balance ratio of the sheet light source is partially adjusted. Adjustable.

It should be noted that the single light source may be, for example, a single LED mounted on the side of the camera housing or optical lens unit 42 . The single LED rotates at the same time as the camera 40 rotates in the range of 0 degrees to 90 degrees, and emits illumination light in the direction of the optical axis of the camera 40 . Also, the overall light intensity of a single LED may be manually adjustable.

Various embodiments have been described above with reference to the drawings, but it goes without saying that the present disclosure is not limited to such examples. It is obvious that a person skilled in the art can conceive of various modifications, modifications, substitutions, additions, deletions, and equivalents within the scope of the claims. Naturally, it is understood that it belongs to the technical scope of the present disclosure. In addition, the constituent elements of the various embodiments described above may be combined arbitrarily without departing from the gist of the invention.

For example, in the first embodiment described above, the camera head arranged at the tip of the scope 11 is provided with three LEDs as illumination light sources, which emit light in the irradiation directions of 0 degrees, 45 degrees, and 90 degrees. , for example, four LEDs may be provided that irradiate 0, 30, 60, and 90 degree irradiation directions, respectively.

The present disclosure efficiently illuminates and images a subject such as the inside of the human body while changing the field of view in a wide angle of view, and adaptively suppresses image quality deterioration of the captured image based on the lighting balance of light and dark on the subject. It is useful as an endoscope and endoscope system.

5 Endoscope system 10 Endoscope 11 Scope 12 Operation unit 13 Branch box 14 Camera head 22 Dimming reset button 23 Illumination balance volume 24 Overall light amount volume 60 Light source control device 80 CCU
84 lighting control unit 91 automatic lighting balance switching control unit 92 PWM control unit

Claims (10)

An endoscope inserted into a subject,
an imaging unit arranged at the distal end of the endoscope for imaging the subject with a variable field of view within a predetermined angle of view;
a plurality of illumination units arranged at the tip portion for illuminating irradiation ranges in a plurality of different directions;
and a detection unit that detects the viewing direction of the imaging unit,
Each of the plurality of illumination units is included in the direction of the field of view of the imaging unit according to the irradiation range of the plurality of illumination units included in the direction of the field of view of the imaging unit detected by the detection unit. Among them, the light amount of the first illumination unit having the largest irradiation range in the viewing direction of the imaging unit is maximized, and the irradiation range in the viewing direction of the imaging unit is smaller than that of the first illumination unit. illuminating by changing the light amount of the illumination light so that the light amount of the illumination light is smaller than that of the first illumination unit ;
Endoscope. Of the plurality of lighting units, a third lighting unit that is not included in the viewing direction of the imaging unit is not lit.
The endoscope according to claim 1. an operation unit disposed on the proximal end side of the endoscope and receiving an operation by a user;
The imaging unit changes the viewing direction according to the user's operation.
The endoscope according to claim 1. an operation unit disposed on the proximal end side of the endoscope and receiving an operation by a user;
The operation unit receives an operation for adjusting a balance ratio of illumination light to the subject from each of the first illumination unit and the second illumination unit .
The endoscope according to claim 1 . an operation unit disposed on the proximal end side of the endoscope and receiving an operation by a user;
The operation unit receives an operation for adjusting an overall light amount based on illumination light to the subject from each of the first illumination unit and the second illumination unit .
The endoscope according to claim 1 . An endoscope system including an endoscope inserted into a subject and a control device for controlling the operation of the endoscope,
The endoscope is
an imaging unit arranged at the distal end of the endoscope for imaging the subject with a variable field of view within a predetermined angle of view;
a plurality of illumination units arranged at the tip portion for illuminating irradiation ranges in a plurality of different directions;
and a detection unit that detects the viewing direction of the imaging unit,
Each of the plurality of illumination units is controlled by the control device according to the irradiation range of the plurality of illumination units included in the viewing direction of the imaging unit detected by the detection unit . Among the illumination units included therein, the light amount of the first illumination unit having the largest irradiation range in the visual field direction of the imaging unit is maximized, and the irradiation range in the visual field direction of the imaging unit is larger than that of the first illumination unit illuminating by changing the light amount of the illumination light so that the light amount of the second illumination unit is smaller than that of the first illumination unit ,
endoscope system. The endoscope further comprises an operation unit arranged on the proximal end side of the endoscope and receiving a user's operation,
The control device controls each of the first illumination section and the second illumination section in accordance with an operation for adjusting a balance ratio of illumination light to the subject from each of the first illumination section and the second illumination section. , instructing to change the balance ratio of the amount of illumination light for the corresponding irradiation range from the current value to another value;
The endoscope system according to claim 6 . The endoscope further comprises an operation unit arranged on the proximal end side of the endoscope and receiving a user's operation,
The control device controls each of the first illumination unit and the second illumination unit according to an operation for adjusting an overall light amount based on the illumination light to the subject from each of the first illumination unit and the second illumination unit. Instructing to change the intensity of the amount of illumination light for the corresponding irradiation range from the current value to another value,
The endoscope system according to claim 6 . The endoscope further includes a third lighting unit as the plurality of lighting units in addition to the first lighting unit and the second lighting unit ,
The control device controls the first illumination unit and the second illumination unit so that the sum of the balance ratios of the amounts of illumination light of the first illumination unit and the second illumination unit among the plurality of illumination units becomes a predetermined value. instructing to change the balance ratio of the light amount of the illumination light to the irradiation range corresponding to each of the second illumination units ;
The endoscope system according to claim 6 . The operation unit has a reset button related to a balance ratio of the amount of illumination light to the subject from each of the first illumination unit and the second illumination unit ,
The control device adjusts the balance ratio of the light amount of the illumination light to the subject from each of the first illumination unit and the second illumination unit in the viewing direction of the imaging unit in response to the pressing operation of the reset button. Returning to the control based on the detection result, the lighting control information defining the relationship between the visual field direction of the imaging unit and the balance ratio of the light amount of each of the plurality of lighting units,
The endoscope system according to claim 7 .

Images