JP6145539B2 - Endoscope light source device - Google Patents

Description

  The present invention relates to an endoscope light source device for simultaneously performing observation using different illumination lights.

  In the medical device field, in order to more effectively diagnose a lesion, an electronic endoscope system capable of simultaneously performing observation using each of a plurality of illumination lights having different wavelength ranges is known. (Patent Document 1).

  In Patent Document 1, a neutral density filter that transmits white light (normal light) for normal observation and a special light filter that transmits only light in a specific wavelength range (special light) are alternately arranged in the circumferential direction. By using illumination light obtained through white lamp light on a rotating plate that rotates in synchronization with the imaging timing, for example, a normal observation image and a special light observation image are alternately captured for each frame. An electronic endoscope apparatus including a light source device that enables simultaneous observation of normal observation and special light observation is described. In addition, since exposure adjustment is performed using a slow-response diaphragm, it cannot follow switching of a very short cycle between normal light and special light. Therefore, proper exposure cannot be obtained for each observation image, and when there is a large difference in the amount of light between normal light and special light, whiteout or blackout occurs. Therefore, in the apparatus of Patent Document 1, the amount of normal light is adjusted using a neutral density filter so that the amounts of normal light and special light match. A metal net is used for the neutral density filter, and the amount of normal light transmitted through the metal net mesh is adjusted.

JP 2011-200377 A

  Also, the amount of special light transmitted through the special light filter varies depending on the type of lamp used. Therefore, if the transmitted light amount of the metal mesh is completely matched with the transmitted light amount of the special light filter, a special metal mesh is used. As a result, it is necessary to produce a large number of types, and the procurement cost of the metal net becomes enormous. Therefore, in reality, the most suitable metal mesh of standard specifications on the market is selected and used. Therefore, the difference in the amount of transmitted light between the special light filter and the metal net is large, the light control is insufficient, and overexposure and underexposure may occur. In addition, since the metal mesh is easily deformed, the process of attaching the metal mesh to the rotating plate requires careful processing, which requires a lot of man-hours.

  According to the embodiment of the present invention, a white light source that emits a white light beam including first and second wavelength ranges used for illumination for endoscopic observation, first illumination light having a first wavelength range, A rotary filter that sequentially switches the second illumination light having the second wavelength range and extracts it from the white light flux, and the rotary filter has first and second filter regions arranged in the circumferential direction. And a rotation driving unit that rotates the rotating plate at a constant speed so that the first illumination light and the second illumination light are switched in accordance with the timing of imaging, and the first and second filters In the region, the first and second illumination lights are respectively extracted from the white light flux and emitted, and the size of the second filter region in the circumferential direction is emitted per rotation of the rotating plate. Time integration of the amount of light of the first and second illumination light The endoscope light source device which is set to be substantially equal is provided.

  According to this configuration, the amount of transmitted illumination light passing through each filter region can be made uniform without using a metal net. In addition, since the size of the second filter region (for example, a slit functioning as an ND filter) in the circumferential direction of the rotating plate can be processed steplessly, without preparing a dedicated member for each wavelength region, The transmitted light amount difference of the illumination light passing through each filter region can be sufficiently reduced, and overexposure and blackout of the observation image are prevented.

  The illumination light in the first wavelength region may be special light, and the illumination light in the second wavelength region may be white light for normal observation.

  In addition, first and second slits extending in the circumferential direction are formed in the first and second filter regions of the rotating plate, respectively, and the first slit selectively selects the first illumination light. It is good also as a structure block | closed with the 1st filter element to permeate | transmit.

  The 1st and 2nd filter area | region is good also as a structure each arrange | positioned in the division area | region which divided | segmented the rotating plate equally in the circumferential direction.

  In addition, in the divided area obtained by dividing the rotating plate into the even number in the circumferential direction, either one of the first and second filter areas is arranged, and the divided area in which the first filter area is arranged; The divided areas where the two filter areas are arranged may be arranged alternately in the circumferential direction.

  Alternatively, the rotation driving unit may be configured to rotate the rotating plate so that the period during which the white light beam passes through the divided region coincides with the period during which one frame or one field is captured.

  According to this configuration, imaging for special light observation using special light transmitted through the filter element and imaging for normal observation using light that is not filtered are performed at equal time intervals for each frame (or one field). Since they are performed alternately, two observation images with relatively smooth and natural movement can be simultaneously acquired based on the imaging data obtained by each imaging.

  The rotating plate is formed with a plurality of concentric circles of filter region rows each having a plurality of filter regions arranged in the circumferential direction, and the rotating filter is a filter region row switch that switches a filter region row into which a white light beam is incident. It is good also as a structure provided with a means.

  According to this configuration, the filter area to be used can be automatically and instantaneously switched.

  Further, the configuration may be such that the amount of light is an execution light amount that has been corrected so that an imaging signal having the same amplitude is obtained when images are captured with the same amount of light.

  As described above, according to the configuration of the embodiment of the present invention, with a simple configuration, the light amount difference between illumination lights is suppressed to be low, and overexposure and blackout are prevented.

FIG. 1 is a block diagram showing a schematic configuration of an electronic endoscope apparatus 1 according to an embodiment of the present invention. FIG. 2 is a front view of the rotary filter 260 built in the electronic endoscope apparatus 1 according to the embodiment of the present invention when viewed from the condenser lens 210 side. FIG. 3 is a diagram for explaining a mechanism for switching the position where the white light beam L from the lamp 208 enters the rotary filter 260. FIG. 4 is a diagram for explaining another example of a mechanism for switching the position where the white light beam L from the lamp 208 is incident on the rotary filter 260.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

  FIG. 1 is a block diagram showing a schematic configuration of an electronic endoscope apparatus 1 according to an embodiment of the present invention. As shown in FIG. 1, the electronic endoscope apparatus 1 of this embodiment includes an electronic endoscope 100, an electronic endoscope processor 200, and one or more monitors 300.

  The electronic endoscope processor 200 includes a system controller 202 and a timing controller 204. The system controller 202 executes various programs stored in the memory 203 and controls the entire electronic endoscope apparatus 1 in an integrated manner. The system controller 202 is connected to the touch panel 218 and changes each operation of the electronic endoscope apparatus 1 and parameters for each operation in accordance with an instruction from the user input from the touch panel 218. The timing controller 204 outputs a clock pulse for adjusting the operation timing of each unit to various circuits in the electronic endoscope apparatus 1.

  The lamp 208 emits a white light beam L after being started by the lamp power igniter 206. As the lamp 208, a high-intensity lamp such as a xenon lamp, a halogen lamp, a mercury lamp, or a metal halide lamp is suitable. The white light beam L radiated from the lamp 208 passes through a rotary filter 260 described later, and is then condensed by the condenser lens 210 and is limited to an appropriate amount of light through a diaphragm (not shown), and is then LCB (Light Carrying Bundle) 102 is incident on the incident end.

  The rotary filter 260 alternately transmits two types of illumination light having different spectra (for example, white light and special light) in synchronization with the imaging timing. By using the rotary filter 260 that operates in synchronization with the imaging, for example, the illumination light used for imaging is switched between white light and special light for each frame (or for each field), and imaging for normal observation and special imaging are performed. Imaging with light observation can be performed alternately. Further, as will be described later, the rotary filter 260 is configured so that the time integrals of the amounts of illumination light (white light or special light) passing through each frame period (or field period) are substantially equal. Therefore, it is not necessary to perform dimming for each frame (or for each field), and even if the above-described stop is used that has a very slow response time with respect to the illumination light switching period, Therefore, appropriate dimming can be performed. Details of the configuration of the rotary filter 260 will be described later.

  Illumination light introduced into the LCB 102 from the incident end propagates through the LCB 102, exits from the exit end of the LCB 102 disposed at the tip of the electronic endoscope 100, and is irradiated onto the subject via the light distribution lens 104. . The reflected light from the subject forms an optical image on the light receiving surface of the solid-state image sensor 108 via the objective lens 106.

  The solid-state imaging device 108 is a single-plate color CCD (Charge-Coupled Device) image sensor in which various filters such as an IR (InfraRed) cut filter 108a and a Bayer array color filter 108b are arranged on the light receiving surface, and forms an image on the light receiving surface. Imaging signals of R, G, and B colors corresponding to the optical image thus generated are generated. The generated imaging signal is subjected to processing such as AD conversion and signal amplification in a driver signal processing circuit 112 provided in a connection portion of the electronic endoscope 100, and then subjected to pre-stage signal processing of the electronic endoscope processor 200. Input to the circuit 220. In another embodiment, the solid-state imaging device 108 is not limited to a CCD image sensor, but may be a CMOS (Complementary Metal Oxide Semiconductor) image sensor.

  In the driver signal processing circuit 112, the R, G, B image signals are converted into image signals composed of the luminance signal Y and the color difference signals Cb, Cr, and further converted into digital signals, and then the electronic endoscope processor. 200 is sent to the pre-stage signal processing circuit 220. In addition, the driver signal processing circuit 112 accesses the memory 114 to read out unique information of the electronic endoscope 100. The unique information of the electronic endoscope 100 recorded in the memory 114 includes, for example, the number of pixels and sensitivity of the solid-state image sensor 108, a compatible rate, a model number, and the like. The driver signal processing circuit 112 outputs the unique information read from the memory 114 to the system controller 202.

  The system controller 202 performs various calculations based on the unique information of the electronic endoscope 100 and generates a control signal. The system controller 202 uses the generated control signals to operate various circuits in the electronic endoscope processor 200 so that processing suitable for the electronic scope connected to the electronic endoscope processor 200 is performed. Control timing.

  The timing controller 204 supplies clock pulses to the driver signal processing circuit 112 in accordance with timing control by the system controller 202. The driver signal processing circuit 112 drives and controls the solid-state imaging device 108 at a timing synchronized with the frame rate of the video processed on the electronic endoscope processor 200 side according to the clock pulse supplied from the timing controller 204.

  The pre-stage signal processing circuit 220 of the electronic endoscope processor 200 performs various image processing on the image signal sent from the driver signal processing circuit 112 of the electronic endoscope 100. The pre-stage signal processing circuit 220 amplifies the luminance signal Y and the color difference signals Cb and Cr sent from the driver signal processing circuit 112 and then sends them to a built-in matrix circuit (not shown), and the illumination light used for imaging. The matrix coefficient value for determining the conversion characteristic is updated in accordance with the spectral characteristic (directly, the spectral characteristic of the optical filter used for filtering the illumination light), and the color correction of the image signal is performed. The matrix circuit converts the input luminance signal Y and color difference signals Cb, Cr into three primary color signals R, G, B and outputs them. The R, G, and B image signals output from the matrix circuit are amplified and adjusted to appropriate signal levels, and then stored in the image memory 230 for each color.

  As will be described later, the switching timing of the normal light and the special light by the rotary filter 260 is synchronized with the switching timing of the imaging period (frame period or field period) in the imaging element 108. Accordingly, the image sensor 108 receives white light during a certain exposure period to generate and output a normal observation image imaging signal, and then receives special light during the subsequent exposure period to generate a special light observation image imaging signal. By repeating this operation, the imaging signals of the respective observation images are alternately output. The image memory 230 includes a normal observation image memory for storing a normal observation image signal and a special light observation image memory for storing a special light observation image signal. The image memory 230 stops writing to the special light observation image memory when writing to the normal observation image memory, and writes to the normal observation image memory when writing to the special light observation image memory. Stop. The switching of the operation mode of the image memory 230 is performed in synchronization with the clock pulse from the timing controller 204.

  Further, as matrix coefficients of the matrix circuit of the pre-stage signal processing circuit 220, coefficients corresponding to white light and special light are prepared, and each matrix coefficient is stored in the memory 222. Based on the clock pulse from the timing controller 204, the type of illumination light (one of normal light or special light) used for imaging of the image signal to be processed next is synchronized with the illumination light switching timing. Corresponding matrix coefficients are sent from the memory 222 to the pre-stage signal processing circuit 220 and set in the matrix circuit.

  The image signal read from the normal observation image memory or the special light observation image memory in the image memory 230 in synchronization with the clock pulse from the timing controller 204 is sent to the subsequent signal processing circuit 240. The post-stage signal processing circuit 240 generates monitor display screen data based on the normal observation and special light observation image signals sent from the image memory 230 and information such as the observation conditions sent from the system controller 202. Screen generation processing is performed, and the generated monitor display screen data is converted into various digital or analog video signals. In the screen generation processing, for example, processing for reducing and combining the observation images to generate a divided display screen, processing for reducing one observation image and inserting it as a sub-screen in a part of the other observation image, and each observation Processing for generating a screen for selecting one of the images and displaying the selected image in full screen, or the operator name, patient name, observation date and time, the type of illumination light used for observation, etc., input via the touch panel 218 A process of superimposing information related to endoscopic observation is performed. Note that the monitor display screen data for simultaneously displaying the normal observation image and the special light observation image on the same monitor 300 can be generated by the processing for generating the divided display screen and the sub-screen. By displaying the normal light observation image and the special light observation image on one screen, the surgeon can easily diagnose and identify the affected area while simultaneously viewing both observation images. The screen generation process is performed based on the control of the system controller 202.

  The video signal generated by the post-stage signal processing circuit 240 is input to the monitor 300 and displayed on the screen. The surgeon observes and treats a site in the body cavity while confirming the observation image displayed on the monitor 300.

  Further, the post-stage signal processing circuit 240 is configured to simultaneously output a plurality of video signals for displaying different screens. The electronic endoscope processor 200 includes a plurality of video output terminals (not shown) corresponding to a plurality of video signals output from the post-stage signal processing circuit 240. The monitor 300 is configured to display different screens. For example, the post-stage signal processing circuit 240 simultaneously generates a video signal for displaying the normal observation image on the full screen and a video signal for displaying the special light observation image on the full screen, and outputs them to another monitor 300 to output the normal observation image. And a special light observation image can be displayed simultaneously.

  Here, the configuration of the rotary filter 260 will be described. FIG. 2 is a front view of the rotary filter 260 according to the present embodiment as viewed from the condenser lens 210 side. FIG. 3 is an enlarged plan view of the vicinity of the rotary filter 260. As illustrated in FIGS. 1 to 3, the rotary filter 260 includes a rotary plate 261, filters 264 a to 264 c fixed to the rotary plate 261, a motor 266, a driver 265 that drives and controls the motor 266, and the rotary plate 261. And a photo interrupter 267 for detecting the rotational position. The center of the rotary plate 261 is connected to the drive shaft 266 a (FIG. 3) of the motor 266 and is driven to rotate by the motor 266. As the motor 266, a stepping motor capable of highly accurate rotation angle control is used.

  The rotating plate 261 is a disk-shaped member in which a plurality of slits 262a to c, 263a to c and an opening 261a are formed. The slits 262a to 262c and 263a to 263c are arc-shaped openings formed on concentric circles around the rotation axis C of the rotating plate 261, respectively. The slits 262a and 263a, 262b and 263b, and 262c and 263c are formed on the same circumference, and constitute a pair of slits. The rotating plate 261 is arranged so that the white light beam L is perpendicularly incident on one of the circumferences where each pair of slits is formed, and is formed on this circumference when the rotating plate 261 rotates at a constant speed. White light beams L are periodically and alternately incident on the slit pairs. Of each pair of slits, filters 264a-c are fitted into one slit 263a-c formed on the half surface (upper left part in FIG. 2) of the rotating plate 261, and the other side (lower right in FIG. 2). The other slits 262a to 262c formed in the portion) are not provided with a filter.

  The filters 264a to 264c are wavelength filters that selectively transmit light in different wavelength ranges, are fitted into the slits 263a to 263c without any gap, and are fixed to the rotating plate 261 with an adhesive or the like. Examples of the filters 264a to 264c include an ultraviolet region near a wavelength of 400 to 500 nm that is effective as excitation light for fluorescence observation, a narrow band near a wavelength of 415 nm or 540 nm that is an absorption region of blood moglobin and is effective for blood vessel observation, Various absorption and reflection type optical filters that selectively transmit a specific wavelength region such as a narrow band near a wavelength of 650 nm effective for deep layer observation are used. A bimodal filter having a plurality of discrete transmission regions can also be used.

  While the white light beam L is incident on the slits 263a to c covered by the filters 264a to 264c, light in a specific wavelength region (that is, special light) among a plurality of wavelength regions included in the white light beam L. Only passes through the rotary filter 260 via the filters 264a-c and the slits 263a-c, and is supplied to the LCB 102 as illumination light for special light observation. Further, while the white light beam L is incident on the slits 262a to 262c not covered with the filter, white light is supplied as illumination light to the LCB 102 without passing through the wavelength filter, and normal observation is performed.

  Further, the center angles of the slits 263a-c in which the filters 264a-c are embedded are uniform, but the center angles of the slits 262a-c not covered by the filter are non-uniform. By changing the size of the central angle of the slits 262a-c, the time during which the white illumination light passing through each slit 262a-c is supplied to the LCB 102 during one rotation of the rotating plate 261, that is, one frame (or The exposure time during the imaging period of one field can be changed. In the present embodiment, the time integral (energy) of the amount of white light supplied to the LCB 102 via each slit 262a-c during one rotation of the rotating plate 261 is formed on the same circumference. The central angles of the slits 262a to 262c are set so as to be approximately equal to the time integration of the amount of special light supplied to the LCB 102 via the slits 263a to 263c and the filters 264a to 264c. As a result, the exposure level becomes substantially constant during normal observation and special light observation. Therefore, if exposure adjustment is performed by controlling the aperture for one observation (eg normal observation), the other observation (eg special light) Appropriate exposure can be obtained even in (observation), and an image free from overexposure and underexposure can be obtained in both observations.

  In addition, an opening 261 a indicating the reference position of the rotating plate 261 is formed on the outer peripheral portion of the rotating plate 261. The opening 261 a is detected by a photo interrupter 267 disposed in the vicinity of the outer peripheral portion of the rotating plate 261 and is used for controlling the rotational position of the rotating plate 261. When the photo interrupter 267 detects the opening 261a, the photo interrupter 267 outputs a reference position detection signal to the driver 265. The opening 261a is formed on the opposite surface (upper left portion in FIG. 2) of the rotating plate 260 where the slits 263a-c covered with the filters 264a-c are formed, and slits 262a-c not covered with the filters 264a-c. It arrange | positions in the boundary part with the other half surface (lower right part in FIG. 2). That is, if the rotation of the rotating plate 261 is completely synchronized with the imaging, the clock pulse of the timing controller 204 and the reference position detection signal of the photo interrupter 267 are output simultaneously. If there is a time difference between the reception of the clock pulse and the reference position detection signal, the driver 265 adjusts the rotation phase of the motor 266 so that this time difference is eliminated.

  Next, switching means for switching the slit pair on which the white light beam L is incident will be described. As shown in FIG. 3, the rotary filter 260 is attached to a linear actuator (not shown), and is configured to be movable in a direction perpendicular to the path of the white light beam L (the arrow direction in the figure). When the surgeon performs an operation of changing the type (wavelength range) of the special light using an operation button (not shown) provided on the operation unit of the touch panel 218 or the electronic endoscope 100, the operation is performed based on this operation. The system controller 202 sends a control signal to the driver 265, moves the rotary filter 260 in a direction perpendicular to the optical axis of the white light beam L (that is, the radial direction of the rotating plate 261), and the pair of slits into which the white light beam L is incident. Is switched. As a result, the type of special light emitted from the rotary filter 260 is switched.

  The switching means (FIG. 3) of the present embodiment described above is configured to switch the slit pair into which the white light beam L is incident by moving the rotary filter 260, but on the contrary, the path of the white light beam L A configuration in which a pair of slits into which the white light beam L is incident is switched by moving a part of the light beam is also possible. An example of the latter configuration is shown in FIG. The switching unit shown in FIG. 4 includes a pair of movable deflection mirrors 272 and 273 and a pair of fixed deflection mirrors 271 and 274. The movable deflection mirrors 272 and 273 are attached to a linear actuator (not shown), and are configured to be movable in the radial direction of the rotating plate 261 (the arrow direction in the figure). By moving the movable deflection mirrors 272 and 273 in the arrow direction by the linear actuator, the path of the white light beam L deflected by the fixed deflection mirror 274 and the movable deflection mirror 273 is moved in the arrow direction, and the slit into which the white light beam L is incident. Pairs are switched. The illumination light emitted from the rotary filter 260 is deflected by the movable deflection mirror 272 and the fixed deflection mirror 271 and introduced into the LCB 102 via the condenser lens 210. In this configuration of another example, the number of optical components is increased as compared with the configuration of FIG. 3, but the movement of the large and heavy rotary filter 260 is not required, so that a small linear actuator can be used, and the switching means Weight reduction is possible.

  Furthermore, an optical filter that cuts ultraviolet light or infrared light in a wavelength region that is not used for normal observation or special light observation may be provided on the path of the white light beam L between the lamp 208 and the rotary filter. Thereby, deterioration of a special optical filter can be suppressed.

  The above is the description of the present embodiment, but the present invention is not limited to the configuration of the present embodiment, and various modifications can be made within the scope of the technical idea expressed by the claims. Is possible.

  For example, in the above embodiment, the size of the central angle of the slits 262a to 262c provided in the rotating plate 261 so that the amount of white light supplied to the LCB 102 and the amount of special light supplied to the LCB 102 during each imaging period are approximately the same. However, the sensitivity of the image sensor and the reflectance of the subject may be different between white light and special light, so that the effective light amount corrected for these effects is comparable. Further, a configuration may be adopted in which the central angle of the slit is set (that is, the amplitude of the obtained image pickup signal is approximately the same).

  In the above embodiment, the normal observation and the special light observation are alternately performed for each frame (or for each field). However, the special light observation using illumination light in two different wavelength ranges is used. It is good also as a structure which performs alternately. In this case, the slits 262a to 262c are provided with optical filters having different transmission wavelength ranges from the filters 264a to 264c.

  Further, in the above-described embodiment, the rotating plate 261 is configured to rotate 1/2 in one imaging period (one frame period or one field period), and the plane of the rotating plate 261 is corresponding to this. The region is divided into two in the circumferential direction, and slits 262a to c and 263a to 263c corresponding to the respective imaging are provided in each divided region, but the rotating plate 261 is divided into a plurality of divisions of three or more (n division). A configuration may be adopted in which slits are arranged in the divided areas, and the rotating plate 261 rotates a plurality of times (n rotations) three or more times during one imaging period. In this case, three or more types of observations (for example, normal observation, blood vessel observation using a wavelength region of 540 nm, and deep layer observation using a wavelength region of 650 nm) can be performed simultaneously. Further, in the case where one cycle of rotation of the rotating plate is configured to be an even number of times of imaging, for example, a slit with a filter and a slit without a filter are alternately arranged in the circumferential direction. It is good also as a structure.

  In the above embodiment, no filter is provided in the slits 262a to 262c through which the illumination light for normal observation passes, but a filter for normal observation may be provided. As a normal observation filter, for example, a filter that cuts a wavelength region other than the visible region or a flattening filter that flattens the wavelength spectrum of a light source in the visible region can be used.

  Moreover, in said embodiment, although filter 264a-c is embedded in 263a-c of the rotating plate 261, it is good also as a structure which covers a slit with a filter from the single side | surface of a rotating plate. Moreover, you may provide the filter holding member holding a filter separately from the rotating plate in which the slit was formed.

  The above embodiment is an example in which the present invention is applied to an electronic endoscope apparatus including an imaging device at the distal end portion of the endoscope. However, the proximal end portion (end portion on the processor side) of the endoscope The present invention can also be applied to another type of endoscope apparatus (for example, a fiberscope in which a video camera is attached to the eyepiece unit) provided with an imaging mechanism.

  Moreover, although said embodiment is a thing of the structure which incorporated the light source device in the processor, the structure which isolate | separated the processor and the light source device is also contained in the scope of the present invention. In this case, wired or wireless communication means for transmitting and receiving timing signals between the processor and the light source device is provided.

  In this embodiment, the solid-state image sensor 108 having R, G, B Bayer array color filters 108b is used, but complementary colors Cy (cyan), Mg (magenta), Ye (yellow), A configuration using a solid-state imaging device having a G (green) filter may also be used.

1 Electronic Endoscope Device 100 Electronic Endoscope 102 LCB
104 Light Distribution Lens 106 Objective Lens 108 Solid-State Image Sensor 200 Electronic Endoscope Processor 202 System Controller 204 Timing Controller 206 Lamp Power Supply Igniter 208 Lamp 210 Condensing Lens 260 Rotating Filters 262a-c, 263a-c Slits 264a-c Filter 267 Photo interrupter 266 Motor 265 Driver 218 Touch panel 300 Monitor

Claims (8)

A white light source that emits a white light beam including first and second wavelength ranges used for illumination for endoscopic observation;
The image of the subject illuminated with the first illumination light having the first wavelength range and the image of the subject illuminated with the second illumination light having the second wavelength range are displayed on one screen of the monitor. A rotating filter for alternately taking out the first illumination light and the second illumination light from the white light flux at a timing synchronized with a predetermined imaging cycle for displaying simultaneously;
With
The rotary filter is
A rotating plate having first and second filter regions arranged in a circumferential direction;
A rotation drive unit that rotates the rotating plate at a constant speed so that the first illumination light and the second illumination light are switched in accordance with the timing of imaging,
In the first and second filter regions, the first and second illumination lights are extracted from the white light flux and emitted, respectively.
The amplitude of the imaging signal output from the image sensor when the subject illuminated with the first illumination light is imaged, and the image sensor output when the subject illuminated with the second illumination light is imaged. The circumferential size of the second filter region is set so that the amplitude of the imaging signal is substantially equal;
Endoscope light source device. The circumferential size of the second filter region is:
It is set in consideration of at least one of a difference in sensitivity of the image sensor and a difference in reflectance of the subject with respect to the first illumination light and the second illumination light.
The endoscope light source device according to claim 1. The illumination light in the first wavelength range is special light,
The illumination light in the second wavelength region is white light for normal observation,
The endoscope light source device according to claim 1 or 2. First and second slits extending in a circumferential direction are formed in the first and second filter regions of the rotating plate, respectively.
The first slit is blocked by a first filter element that selectively transmits the first illumination light;
The endoscope light source device according to any one of claims 1 to 3. The first and second filter regions are respectively disposed in divided regions obtained by equally dividing the rotating plate in the circumferential direction.
The light source device for endoscopes according to any one of claims 1 to 4. Either one of the first and second filter regions is disposed in the divided region obtained by dividing the rotating plate into an even number in the circumferential direction.
The divided areas in which the first filter areas are arranged and the divided areas in which the second filter areas are arranged are alternately arranged in the circumferential direction.
The light source device for an endoscope according to claim 5. The rotation driving unit rotates the rotating plate so that a period in which the white light beam passes through the divided region coincides with a period in which imaging of one frame or one field is performed;
The endoscope light source device according to claim 5 or 6. In the rotating plate, a plurality of filter region rows composed of a plurality of filter regions arranged in the circumferential direction are formed on a concentric circle,
The rotary filter includes a filter region row switching unit that switches the filter region row on which the white light beam enters.
The light source device for endoscopes according to any one of claims 1 to 7.

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