JP2022079732A - Position adjustment method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a position adjustment method capable of decreasing variation of hue of a display image at each time of endoscopic diagnoses when a plurality of monochrome semiconductor light sources respectively emit light of a plurality of colors.

SOLUTION: A lens holder which holds collimator lenses 75 and 77 is moved in an optical axis direction by using a guide mechanism and a moving mechanism so that peaks of light volume waveforms of respective color light beams indicating focus positions of respective color light match each other. The lens holder is pressed by a fixing mechanism so as to fix a position of an optical member in the lens holder.

SELECTED DRAWING: Figure 13

COPYRIGHT: (C)2022,JPO&INPIT

Description

The present invention relates to a position adjusting method performed by a light source device for an endoscope that supplies illumination light to the endoscope.

Endoscopic diagnosis using an endoscopic system is actively performed in the medical field. The endoscope system includes an endoscope, a processor device that processes an image signal output by the endoscope, and a light source device for an endoscope that supplies illumination light to the endoscope (hereinafter, simply referred to as a light source device). It is equipped with.

The endoscope has an insertion portion to be inserted into the living body, and at the tip of the insertion portion, an illumination window for irradiating the observation target with illumination light and an observation window for imaging the observation target are arranged. There is. The endoscope has a built-in light guide consisting of a fiber bundle in which optical fibers are bundled. The light guide guides the illumination light supplied from the light source device to the illumination window. The incident end of the light guide into which the illumination light is incident is arranged in the light source device, and the emission end of the light guide from which the illumination light is emitted is arranged in the back of the illumination window.

An image sensor such as a CCD (Charge Coupled Device) image sensor is arranged behind the observation window. The image pickup sensor captures an observation target irradiated with illumination light and outputs an image signal. The processor device generates a display image for observation based on the image signal and displays it on the monitor.

When the endoscopic diagnosis is completed, the endoscope is removed from the processor device and the light source device, and is cleaned and disinfected. Then, when the next endoscopic diagnosis is started, the processor device and the light source device are connected again. In addition, in the medical field, there are multiple types of endoscopes of the same model, or multiple types of endoscopes with specifications according to the content of the endoscope diagnosis, and the processor device and light source device are of the same model. Multiple endoscopes and multiple types of endoscopes with different specifications can be interchangeably connected.

Conventionally, a xenon lamp or a halogen lamp that emits white light has been used as a light source in a light source device, but recently, instead of these, a laser diode (LD) or a light emitting diode (LED: Light Emitting Diode) has been used. A light source device using a semiconductor light source having a light emitting element such as the above has been proposed (see Patent Document 1).

Patent Document 1 describes a light source device including blue, green, and red semiconductor light sources that emit three colors of light, blue light, green light, and red light, respectively, and supplies the three colors of light as white light. The light source device of Patent Document 1 includes three first optical systems (first lens 26a, second lens 26b, third lens 26c), second optical system (fourth lens 26d), and third optical system (first). A dichroic mirror 25a and a second dichroic mirror 25b) are provided. The three first optical systems transmit three colors of light from blue, green, and red semiconductor light sources, respectively. The second optical system focuses three colors of light on the incident end of the light guide. The third optical system combines the optical paths of the three colors of light that have passed through the first optical system.

Japanese Unexamined Patent Publication No. 2015-047402

In a light source device that supplies light of multiple colors from a plurality of monochromatic semiconductor light sources as illumination light as in Patent Document 1, all of the light of the plurality of colors emitted from the second optical system is connected to the incident end of the light guide. To be precise, it is ideal to focus on the incident end of the fiber bundle that constitutes the light guide.

However, in the light source device of Patent Document 1, as shown in FIG. 25, blue light BL (indicated by a broken line), green light GL (indicated by a thick solid line), and red light RL (thin) emitted from the second optical system 200. The respective focal positions BFP, GFP, and RFP (shown by the solid line) are displaced on the optical axis OA, which may cause a change in the tint of the displayed image, so-called color shift.

Factors that cause the focal positions to shift include assembly errors and individual differences in each part of the configuration that supplies illumination light, such as blue, green, red semiconductor light sources, and first to third optical systems. For example, when the distance between the blue semiconductor light source and the first optical system that transmits the blue light BL is deviated due to an assembly error, the focal position BFP of the blue light BL is also deviated. Alternatively, if the wavelength range or center wavelength of the red light RL deviates due to individual differences in the red semiconductor light source, the refractive index of the red light RL in the first optical system and the third optical system changes, so that the focal position of the red light RL changes. It shifts.

When each focal position shifts, the light intensity waveforms BWW (indicated by a broken line), GW (indicated by a thick solid line), and RW (in a thin solid line) representing the amount of light on the optical axis OA of the three colors of light BL, GL, and RL in FIG. As shown in (shown), the peaks of the light amounts of the three colors of light BL, GL, and RL corresponding to each focal position are also shifted on the optical axis OA. The light intensity waveform is a chevron waveform that peaks at the focal position and has a symmetrical dip before and after the focal position. Further, each light amount waveform BW, GW, and RW have substantially the same shape.

When the peaks of the respective light amount waveforms BW, GW, and RW deviate from each other, the light amount balance of the three colors of light BL, GL, and RL fluctuates depending on the distance from the second optical system 200. For example, in the focal position RFP of the red light RL, the light amount of the red light RL is the highest, followed by the green light GL and the blue light BL in that order. On the contrary, at the focal position BFP of the blue light BL, the light amount of the blue light BL is the highest, followed by the green light GL and the red light RL in that order.

In such a case, the balance of the light amounts of the three colors of light BL, GL, and RL incident on the incident end 202 varies depending on the positional relationship between the second optical system 200 and the incident end 202 of the light guide 201, and as a result, the displayed image is displayed. Color shift that changes the color will occur. For example, when the incident end 202B is at the focal position GFP of the green light GL as in the light guide 201B, the illumination light becomes greenish because the amount of the green light GL is the highest, and the entire display is greenish. Image 203G is generated. Further, when the incident end 202A is at the focal position RFP of the red light RL as in the light guide 201A, the display image 203R having a reddish color as a whole is generated, and the incident end 202C is blue as in the light guide 201C. When it is at the focal position BFP of the optical BL, the display image 203B having a bluish tint as a whole is generated.

As described above, the endoscope is removed from the light source device or connected to the light source device at each endoscope diagnosis. Further, when one light source device shares a plurality of endoscopes of the same model, the second optical system 200 and the incident end 202 are due to individual differences of the plurality of endoscopes even if they are of the same model. The positional relationship with and changes. Further, when one light source device shares a plurality of types of endoscopes having different specifications, some of the plurality of types of endoscopes have different positional relationships between the second optical system 200 and the incident end 202. exist. Therefore, the positional relationship between the second optical system 200 and the incident end 202 is not always the same, and differs depending on the connection condition to the light source device, individual differences of the endoscope, and specifications. Therefore, if the focal positions of the light of a plurality of colors are deviated from each other, the color of the displayed image may change every time the endoscopic diagnosis is made.

Since the endoscopic diagnosis is performed based on a subtle change in the color of the observation target, it is very important to reduce the change in the color of the displayed image at each time of the endoscopic diagnosis. However, if the color of the displayed image changes every time the endoscopic diagnosis is performed as described above, the operator feels uncomfortable and the endoscopic diagnosis becomes difficult.

The present invention provides a position adjusting method capable of reducing a change in the tint of a displayed image at each time of endoscopic diagnosis when a plurality of monochromatic semiconductor light sources that emit light of a plurality of colors are used. With the goal.

In the position adjusting method of the present invention, a light source device for an endoscope that supplies illumination light to a light guide of an endoscope uses a plurality of monochromatic semiconductor light sources that emit light of a plurality of colors as illumination light, and at least one optical member. A first optical system configured to transmit multiple colors of light from a plurality of monochromatic semiconductor light sources, and a plurality of colors of light transmitted through the plurality of first optical systems to be focused on the incident end of the light guide. 2 In the case where the optical system and the position adjusting mechanism for adjusting the position of the optical member in the optical axis direction of the first optical system are provided, the guide mechanism and the moving mechanism are used to indicate the focal position of each colored light. A moving step that moves the lens holder that holds the optical member in the optical axis direction so that the peaks of the light amount waveform match, and a fixing mechanism that presses the lens holder to fix the position of the optical member in the lens holder. Has steps and.

It is preferable that the moving mechanism moves the lens holder in the optical axis direction by converting the rotary motion into a straight motion. A slotted hole is provided in the lens holder, and in the moving step, the eccentric shaft of the eccentric driver is fitted into the slotted hole, and a rotational motion is applied to the eccentric driver to rotate the eccentric shaft along the slotted hole. , It is preferable to move the lens holder in the optical axis direction by a straight motion. In the fixing step, it is preferable that the position of the optical member is fixed by using a fixing tool, and the fixing tool covers the bearing hole through which the eccentric shaft is inserted. In the fixing step, it is preferable to press the lens holder from the direction intersecting the optical axis direction by the fixing mechanism.

According to the present invention, it is possible to reduce the change in color of the displayed image at each time of endoscopic diagnosis.

It is an external view of an endoscope system. It is a front view of the tip of an endoscope. It is explanatory drawing of the endoscope system which shares a plurality of endoscopes with one processor device and a light source device. It is a block diagram of an endoscope system. It is sectional drawing which shows the blue semiconductor light source. It is a top view which shows the blue semiconductor light source. It is a graph which shows the emission spectrum of the blue light emitted by the blue semiconductor light source. It is a graph which shows the emission spectrum of the green light emitted by the green semiconductor light source. It is a graph which shows the emission spectrum of the red light emitted by a red semiconductor light source. It is a graph which shows the emission spectrum of the white light which is composed of blue light, green light, and red light. It is a graph which shows the spectral characteristic of the micro color filter of an image pickup sensor. It is explanatory drawing which shows the irradiation timing of white light and the operation timing of an image pickup sensor. It is a figure which shows the arrangement of each semiconductor light source, and the detailed structure of an optical system group. It is an exploded perspective view of a lens holder and a housing. FIG. 3 is a perspective view of a lens holder, a housing, and an eccentric driver. It is explanatory drawing which shows the mode that the lens holder is moved in the optical axis direction by using the eccentric driver in the state which the lens holder is temporarily fixed to the housing. It is explanatory drawing which shows the change of the focal position by the movement of a collimating lens in the optical axis direction. It is a block diagram of a detection unit. It is explanatory drawing which shows the relationship between the position of the incident end of a light guide, and the display image when each focal position of blue light, green light, and red light is deviated. It is explanatory drawing which shows the relationship between the position of the incident end of a light guide, and the display image when each focal position of blue light, green light, and red light is coincident. It is a figure which shows the arrangement of each semiconductor light source, and the detailed structure of an optical system group in the case where the adjustment mechanism is provided for a blue semiconductor light source and a red semiconductor light source instead of a collimating lens. It is a figure which shows the arrangement of each semiconductor light source, and the detailed structure of an optical system group in the case where the adjustment mechanism is provided for a blue semiconductor light source and a red semiconductor light source in addition to a collimating lens. It is a figure which shows the arrangement of each semiconductor light source, and the detailed structure of an optical system group when a purple semiconductor light source is added. It is a graph which shows the emission spectrum of the purple light emitted by the purple semiconductor light source. It is explanatory drawing which shows the relationship between the position of the incident end of the light guide, and the display image when each focal position of blue light, green light, and red light is deviated in the conventional light source apparatus.

In FIG. 1, the endoscope system 10 includes an endoscope 11 that captures an observation target in a living body, a processor device 12 that generates a display image for observation based on an image signal obtained by the imaging, and an observation target. It is provided with a light source device 13 that supplies illumination light to the endoscope 11 to the endoscope 11. A monitor 14 for displaying a display image and an operation input unit 15 such as a keyboard and a mouse are connected to the processor device 12.

The endoscope 11 is a universal cord that connects an insertion unit 16 to be inserted into a living body, an operation unit 17 provided at the base end portion of the insertion unit 16, the endoscope 11, a processor device 12, and a light source device 13. It is equipped with 18.

The insertion portion 16 is composed of a tip portion 19, a curved portion 20, and a flexible tube portion 21, which are connected in order from the tip. As shown in FIG. 2, on the tip surface of the tip portion 19, an illumination window 22 for irradiating the observation target with illumination light, an observation window 23 for imaging the observation target, and an observation window 23 are sent for cleaning. An air supply / water supply nozzle 24 for performing air / water supply, and a forceps outlet 25 for projecting a treatment tool such as a forceps or an electric knife to perform various treatments are provided. An image pickup sensor 56 and an objective optical system 63 for imaging (both see FIG. 4) are built in the back of the observation window 23.

The curved portion 20 is composed of a plurality of connected curved pieces, and by operating the angle knob 26 of the operating portion 17, the curved portion 20 bends in the vertical and horizontal directions. In FIG. 1, the upward bending motion is shown by a broken line. By bending the curved portion 20, the tip portion 19 is directed in a desired direction. The flexible tube portion 21 is flexible so that it can be inserted into a winding tube such as the esophagus or the intestine. The insertion unit 16 has a communication cable for communicating a drive signal for driving the image pickup sensor 56 and an image signal output by the image pickup sensor 56, and a light guide 55 for guiding the illumination light supplied from the light source device 13 to the illumination window 22 ( (See FIG. 4) and the like are inserted.

In addition to the amble knob 26, the operation unit 17 has a forceps port 27 for inserting a treatment tool, an air supply / water supply button 28 operated when air supply / water supply is performed from the air supply / water supply nozzle 24, and a still image. A release button (not shown) for shooting is provided.

A communication cable and a light guide 55 extending from the insertion portion 16 are inserted into the universal cord 18. A connector 29 is attached to one end of the universal cord 18 on the processor device 12 side and the light source device 13 side. The connector 29 is a composite type connector including a communication connector 29A and a light source connector 29B. The communication connector 29A and the light source connector 29B are detachably connected to the processor device 12 and the light source device 13, respectively. One end of the communication cable is arranged on the communication connector 29A, and the incident end 61 (see FIG. 4) of the light guide 55 is arranged on the light source connector 29B.

When the endoscopic diagnosis is completed, the connection of the connector 29 is disconnected, and the endoscope 11 is removed from the processor device 12 and the light source device 13 to be cleaned and disinfected. Then, when the next endoscopic diagnosis is started, the processor device 12 and the light source device 13 are connected again.

In FIG. 1, only one endoscope 11 is shown, but as shown in FIG. 3, a plurality of endoscopes of the same model (indicated by reference numerals 11A to 11C) or the inside of the endoscope 11 are shown. A plurality of types (indicated by reference numerals 11D and 11E) having different specifications according to the contents of the endoscopic diagnosis are prepared. The processor device 12 and the light source device 13 can interchangeably connect a plurality of endoscopes 11A to 11C of the same model and a plurality of types of endoscopes 11D and 11E having different specifications.

In FIG. 4, the light source device 13 includes a blue semiconductor light source 35, a green semiconductor light source 36, a red semiconductor light source 37, an optical system group 41, and semiconductor light sources 35 to 37, respectively, which emit three lights of blue, green, and red. It includes a light source control unit 42 that controls driving.

As light emitting elements, the semiconductor light sources 35 to 37 are a blue LED 43 that emits light in the blue wavelength band (blue light BL), a green LED 44 that emits light in the green wavelength band (green light GL), and light in the red wavelength band. Each has a red LED 45 that emits (red light RL). As is well known, the LEDs 43 to 45 are formed by joining a P-type semiconductor and an N-type semiconductor. Then, when a voltage is applied, electrons and holes are recombined over the bandgap near the PN junction to allow a current to flow, and energy corresponding to the bandgap is emitted as light at the time of recombination. The amount of light emitted from each of the LEDs 43 to 45 increases or decreases as the power supply increases or decreases.

Drivers 50, 51, and 52 are connected to the LEDs 43 to 45, respectively. The light source control unit 42 controls the lighting, extinguishing, and the amount of light of the LEDs 43 to 45 via the drivers 50 to 52. The amount of light is controlled by changing the power supplied to each of the LEDs 43 to 45 based on the exposure control signal from the processor device 12.

The drivers 50 to 52 light the LEDs 43 to 45 by continuously applying a drive current to the LEDs 43 to 45 under the control of the light source control unit 42. Then, the power supplied to each of the LEDs 43 to 45 is changed by changing the value of the applied drive current according to the exposure control signal, and the amount of light of each color light of blue light BL, green light GL, and red light RL is controlled. do. It should be noted that PAM (Pulse Amplitude Modulation) control that changes the amplitude of the drive current pulse by giving the drive current in a pulse shape instead of continuously giving it, and PWM (Pulse Width Modulation) control that changes the duty ratio of the drive current pulse. May be done.

The optical system group 41 combines the optical paths of each color light of blue light BL, green light GL, and red light RL into one optical path, and collects each color light on the incident end 61 of the light guide 55 of the endoscope 11. Although not shown, the light source connector 29B is provided with an engaging member such as a C ring that engages with the receptacle connector 54, and the receptacle connector 54 is in contact with the outer peripheral surface of the light source connector 29B. A regulating member is provided to regulate the amount of the light source connector 29B inserted into the receptacle connector 54. Further, the light source connector 29B and the receptacle connector 54 are each provided with protective glass.

The endoscope 11 includes a light guide 55, an image pickup sensor 56, an analog processing circuit 57 (AFE: Analog Front End), and an image pickup control unit 58. The light guide 55 is composed of a cylindrical fiber bundle 59 in which a plurality of optical fibers are bundled, and a protective tube 60 that covers the outer periphery of the fiber bundle 59. When the light source connector 29B is connected to the light source device 13, the incident end 61 of the light guide 55 (fiber bundle 59) arranged in the light source connector 29B faces the optical system group 41. The emission end of the light guide 55 located at the tip portion 19 is branched into two at the front stage of the illumination window 22 so that the light is guided to the two illumination windows 22.

An irradiation lens 62 is arranged behind the illumination window 22. The illumination light supplied from the light source device 13 is guided to the irradiation lens 62 by the light guide 55 and is emitted from the illumination window 22 toward the observation target. The irradiation lens 62 is composed of a concave lens, and widens the divergence angle of the light emitted from the light guide 55. As a result, it is possible to irradiate a wide range of the observation target with the illumination light.

An objective optical system 63 and an image pickup sensor 56 are arranged behind the observation window 23. The image to be observed is incident on the objective optical system 63 through the observation window 23, and is imaged on the image pickup surface 56A of the image pickup sensor 56 by the objective optical system 63.

The image pickup sensor 56 is composed of a CCD image sensor, a CMOS (Complementary Metal-Oxide Semiconductor) image sensor, or the like, and a plurality of photoelectric conversion elements constituting pixels such as a photodiode are arranged in a matrix on the image pickup surface 56A. There is. The image pickup sensor 56 photoelectrically converts the light received by the image pickup surface 56A, and accumulates a signal charge corresponding to the amount of light received in each pixel. The signal charge is converted into a voltage signal by the amplifier and read out. The voltage signal is output from the image pickup sensor 56 to the AFE 57 as an image signal.

The AFE57 includes a correlated double sampling circuit, an automatic gain control circuit, and an analog / digital converter (all not shown). The correlated double sampling circuit performs a correlated double sampling process on the analog image signal from the image pickup sensor 56 to remove noise caused by resetting the signal charge. The automatic gain control circuit amplifies the image signal from which noise has been removed by the correlated double sampling circuit. The analog / digital converter converts the image signal amplified by the automatic gain control circuit into a digital image signal having a gradation value corresponding to a predetermined number of bits and outputs the digital image signal to the processor device 12.

The image pickup control unit 58 is connected to the controller 65 in the processor device 12, and inputs a drive signal to the image pickup sensor 56 in synchronization with the reference clock signal input from the controller 65. The image pickup sensor 56 outputs an image signal to the AFE 57 at a predetermined frame rate based on the drive signal from the image pickup control unit 58.

The image pickup sensor 56 is a color image pickup sensor, and the image pickup surface 56A is provided with three color micro color filters, a blue micro color filter (B filter), a green micro color filter (G filter), and a red micro color filter (R filter). And each filter is assigned to each pixel. The array of each filter is, for example, a Bayer array.

In the following description, the pixel to which the B filter is assigned is referred to as a B pixel, the pixel to which the G filter is assigned is referred to as a G pixel, and the pixel to which the R filter is assigned is referred to as an R pixel. Further, the image signal output from the B pixel is referred to as a B image signal, the image signal output from the G pixel is referred to as a G image signal, and the image signal output from the R pixel is referred to as an R image signal.

In addition to the controller 65, the processor device 12 includes a DSP (Digital Signal Processor) 66, an image processing unit 67, a frame memory 68, and a display control unit 69. The controller 65 has a CPU (Central Processing Unit), a ROM (Read Only Memory) for storing a control program and setting data required for control, a RAM (Random Access Memory) for loading the program and functioning as a working memory, and the like. , The CPU controls each part of the processor device 12 by executing a control program.

The DSP 66 acquires an image signal from the image sensor 56. The DSP 66 performs pixel interpolation processing on each of the B image signal, the G image signal, and the R image signal corresponding to each pixel of the B pixel, the G pixel, and the R pixel. In addition, the DSP 66 performs signal processing such as gamma correction and white balance correction for each of the B, G, and R image signals.

Further, the DSP 66 calculates an exposure value based on each image signal so as to increase the amount of illumination light when the amount of light of the entire image is insufficient (underexposure), while when the amount of light is too high. In (overexposure), an exposure control signal for controlling to reduce the amount of illumination light is output to the controller 65. The controller 65 transmits an exposure control signal to the light source control unit 42 of the light source device 13.

The frame memory 68 stores the image signal output by the DSP 66 and the processed image signal processed by the image processing unit 67. The display control unit 69 reads out the image processed image signal from the frame memory 68, converts it into a video signal such as a composite signal or a component signal, and outputs the image signal to the monitor 14.

The image processing unit 67 generates a display image based on the image signals of B, G, and R. This display image is output to the monitor 14 through the display control unit 69. The image processing unit 67 generates a display image every time the image signal in the frame memory 68 is updated.

As shown in FIGS. 5 and 6, the blue semiconductor light source 35 includes a substrate 75 on which the blue LED 43 is mounted, a mold 77 formed on the substrate 75 and a cavity 76 for accommodating the blue LED 43, and the cavity 76. It is composed of the resin 78 enclosed in. The blue LED 43 is connected to the substrate 75 by wiring 79. Such a mounting form of the blue semiconductor light source 35 is generally called a surface mount type.

The cavity 76 has a rectangular opening, and the width becomes narrower toward the substrate 75 side. Blue light BL is emitted from the rectangular opening of the cavity 76. That is, the opening of the cavity 76 functions as a light emitting portion of the blue light BL. Further, the inner surface of the cavity 76 functions as a reflector that reflects blue light BL. The dimensions of the opening of the cavity 76 are, for example, 2 mm on the long side and 1.5 mm on the short side. A diffusing material that diffuses light is dispersed in the resin 78. Since each of the semiconductor light sources 35 to 37 has basically the same configuration, the blue semiconductor light source 35 will be described as an example, and the description of the green and red semiconductor light sources 36 and 37 will be omitted.

As shown in FIG. 7, the blue semiconductor light source 35 has, for example, a wavelength component in the vicinity of 420 nm to 500 nm, which is a wavelength band of blue, and emits blue light BL having a center wavelength of 460 ± 10 nm and a half width of 25 ± 10 nm. Further, as shown in FIG. 8, the green semiconductor light source 36 has, for example, a wavelength component in the vicinity of 480 nm to 600 nm, which is a green wavelength band, and emits green light GL having a center wavelength of 550 ± 10 nm and a half width of 100 ± 10 nm. do. Further, as shown in FIG. 9, the red semiconductor light source 37 has a wavelength component in the vicinity of, for example, 600 nm to 650 nm, which is a wavelength band of red, and emits red light RL having a center wavelength of 625 ± 10 nm and a half width of 20 ± 10 nm. .. The center wavelength indicates the wavelength at the center of the width of the emission spectrum of each color light, and the half width is a wavelength range indicating half of the peak of the emission spectrum of each color light.

FIG. 10 shows the emission spectra of the mixed light of the blue light BL, the green light GL, and the red light RL in which the optical paths are coupled in the optical system group 41. This mixed light is used as white light WL which is illumination light. In order to maintain the same color rendering property as the white light emitted by the xenon light source, the white light WL prevents a wavelength band having no light intensity component from being generated in its emission spectrum.

FIG. 11 is a graph showing the spectral characteristics of the B filter, the G filter, and the R filter provided on the image pickup surface 56A of the image pickup sensor 56. The B pixel to which the B filter is assigned is sensitive to light in the wavelength band of about 380 nm to 560 nm, and the G pixel to which the G filter is assigned is sensitive to light in the wavelength band of about 450 nm to 630 nm. Further, the R pixel to which the R filter is assigned is sensitive to light in the wavelength band of about 580 nm to 800 nm. The blue light BL, the green light GL, and the red light RL constituting the white light WL mainly correspond to the B pixel for the reflected light corresponding to the blue light BL and the G pixel and the red light RL mainly for the reflected light corresponding to the green light GL. The reflected light is received mainly by the R pixel.

In FIG. 12, the image pickup sensor 56 performs a storage operation of accumulating signal charges in pixels and a reading operation of reading out the accumulated signal charges within the acquisition period of an image signal of one frame. Each semiconductor light source 35 to 37 is turned on according to the timing of the accumulation operation of the image pickup sensor 56, and white light WL (BL + GL + RL) composed of a mixed light of blue light BL, green light GL, and red light RL is irradiated to the observation target. , The reflected light is incident on the image pickup sensor 56. The image pickup sensor 56 color-separates the reflected light of the white light WL by each filter. The B pixel receives the reflected light corresponding to the blue light BL, the G pixel receives the reflected light corresponding to the green light GL, and the R pixel receives the reflected light corresponding to the red light RL. The image pickup sensor 56 sequentially outputs an image signal for one frame according to the frame rate according to the read timing.

In FIG. 13, the optical system group 41 is a collimating lens 75, 76, 77 that guides each color light from each semiconductor light source 35 to 37 to an incident end 61, and each color transmitted through each collimating lens 75 to 77. It is composed of dichroic mirrors 78 and 79 that combine the optical paths of light, and a condenser lens 80 that collects each color light on the incident end 61.

The collimating lenses 75 to 77 transmit each color light from each of the semiconductor light sources 35 to 37 to make each color light substantially parallel. The collimating lenses 75 to 77 constitute a plurality of first optical systems, and correspond to optical members constituting the first optical system. The dichroic mirrors 78 and 79 are optical members in which a dichroic filter having a predetermined transmission characteristic is formed on a transparent glass plate. The dichroic mirrors 78 and 79 are provided between the collimating lenses 75 to 77 and the condenser lens 80. The dichroic mirrors 78 and 79 form a third optical system. The condenser lens 80 constitutes a second optical system.

The green semiconductor light source 36 is arranged at a position where its optical axis coincides with the optical axis of the light guide 55. The green semiconductor light source 36 and the red semiconductor light source 37 are arranged so that their optical axes are orthogonal to each other. A dichroic mirror 78 is provided at a position where the optical axes of the green semiconductor light source 36 and the red semiconductor light source 37 are orthogonal to each other. Similarly, the blue semiconductor light source 35 is also arranged so as to be orthogonal to the optical axis of the green semiconductor light source 36, and the dichroic mirror 79 is provided at a position where these optical axes are orthogonal to each other.

The dichroic mirror 78 is arranged at an angle of 45 ° with respect to the optical axis of the green semiconductor light source 36 and the optical axis of the red semiconductor light source 37, respectively. Further, the dichroic mirror 79 is arranged at an inclination of 45 ° with respect to the optical axis of the blue semiconductor light source 35 and the optical axis of the green semiconductor light source 36, respectively.

The dichroic filter of the dichroic mirror 78 has a characteristic of reflecting light in a red wavelength band of, for example, about 600 nm or more, and transmitting light in a blue or green wavelength band of less than about 600 nm. The dichroic mirror 78 transmits the green light GL from the green semiconductor light source 36 to the downstream side and reflects the red light RL from the red semiconductor light source 37. As a result, the optical paths of the green light GL and the red light RL are combined.

On the other hand, the dichroic filter of the dichroic mirror 79 has a characteristic of reflecting light in a blue wavelength band of, for example, less than about 480 nm and transmitting light in a green and red wavelength band of about 480 nm or more. Therefore, the dichroic mirror 79 transmits the green light GL transmitted through the dichroic mirror 78 and the red light RL reflected by the dichroic mirror 78. Further, the dichroic mirror 79 reflects the blue light BL from the blue semiconductor light source 35. By the action of the dichroic mirror 79, all the optical paths of the blue light BL, the green light GL, and the red light RL are combined to generate the white light WL.

Among the collimating lenses 75 to 77, the collimating lens 75 facing the blue semiconductor light source 35 excluding the collimating lens 76 facing the green semiconductor light source 36 and the collimating lens 77 facing the red semiconductor light source 37 have a position adjusting mechanism (hereinafter,). 81, 82 (simply referred to as an adjusting mechanism) are provided. The adjustment mechanisms 81 and 82 adjust the positions of the collimating lenses 75 and 77 in the optical axis direction to adjust the focal positions of the blue light BL and the red light RL emitted from the condenser lens 80, and adjust the focal positions of the blue light BL. , Green light GL, Red light RL is a mechanism for matching the focal positions of each color light. More specifically, the adjusting mechanisms 81 and 82 align the focal positions of the colored lights by moving the collimating lenses 75 and 77 in the optical axis direction.

In a light source device having a plurality of monochromatic semiconductor light sources such as the light source device 13 having the blue semiconductor light source 35, the green semiconductor light source 36, and the red semiconductor light source 37 of the present embodiment, as described with reference to FIG. The respective focal positions BFP, GFP, and RFP of the blue light BL, the green light GL, and the red light RL emitted from the lens 80 may be displaced on the optical axis OA. The adjustment mechanisms 81 and 82 have the focal position BFP of the blue light BL emitted from the condenser lens 80, red, in order to eliminate the color shift in which the color tone of the displayed image changes due to the shift of each focal position. The focal position RFP of the optical RL is matched with the focal position GFP of the green light GL. That is, in the present embodiment, the green light GL corresponds to the light of one color, and the blue light BL and the red light RL correspond to the light of the remaining colors.

In FIGS. 14 and 15, which show the specific configuration of the adjusting mechanism 81, the collimating lens 75 is held by the cylindrical lens holder 90 and attached to the housing 91 of the optical system group 41. An elongated hole 92 is provided in the upper portion of the lens holder 90, and a guide protrusion 93 is provided in the lower portion facing the elongated hole 92. The elongated hole 92 is formed along a direction perpendicular to the optical axis OA. Further, the elongated hole 92 is formed so that its center coincides with the optical axis OA when viewed from above and is symmetrical with respect to the optical axis OA. The elongated hole 92 functions as a moving mechanism for moving the lens holder 90, that is, the collimating lens 75 in the optical axis OA direction. The guide protrusion 93 is formed over the entire width of the lens holder 90 along the direction parallel to the optical axis OA.

The housing 91 is formed with a fitting hole 95 into which the lens holder 90 is fitted. A notch 96 is provided in the upper part of the fitting hole 95, and a guide groove 97 is provided in the lower part facing the notch 96. The notch 96 is provided to expose the upper portion of the lens holder 90 provided with the elongated hole 92 when the lens holder 90 is fitted into the fitting hole 95. Like the guide protrusion 93, the guide groove 97 is formed over the entire width of the fitting hole 95 along the direction parallel to the optical axis OA.

The guide groove 97 receives the guide protrusion 93 when the lens holder 90 is fitted into the fitting hole 95. The guide protrusion 93 and the guide groove 97 guide the movement of the lens holder 90, that is, the collimating lens 75 in the optical axis OA direction. That is, the guide protrusion 93 and the guide groove 97 function as a guide mechanism.

A bearing portion 98 is provided on the upper portion of the notch 96. The bearing portion 98 is provided at a position facing the upper portion of the lens holder 90 exposed by the notch 96. A bearing hole 99 is formed in the bearing portion 98.

After fitting the lens holder 90 into the fitting hole 95, the fixture 100 is attached to the housing 91. The fixture 100 includes a main body portion 101 having a shape that resembles the upper part of the lens holder 90 exposed by the notch 96, and a mounting portion 102 that projects from both ends of the main body portion 101. An insertion hole 104 is formed in the mounting portion 102. A screw 105 is inserted into the insertion hole 104. The screw 105 is screwed into the screw hole 106 formed on the upper surface of the housing 91.

When the fixture 100 is fastened and fixed to the housing 91 with screws 105, the main body 101 comes into close contact with the upper portion of the lens holder 90 exposed by the notch 96, and presses the lens holder 90 from above. As a result, the movement of the lens holder 90 in the optical axis OA direction is restricted, and the position of the lens holder 90, that is, the collimating lens 75 is fixed. These fixtures 100, screws 105, and screw holes 106 function as fixing mechanisms.

FIG. 15 shows a state of temporary fixing before the lens holder 90 is fitted into the fitting hole 95 and the fixture 100 is attached to the housing 91. In this temporarily fixed state, the lens holder 90, that is, the collimating lens 75 can be moved in the optical axis OA direction by using the eccentric driver 110.

The eccentric driver 110 includes a grip 111 gripped by an operator, a rotation shaft 112 protruding from the lower part of the grip 111, and an eccentric shaft 113 protruding from the lower part of the rotation shaft 112. The grip 111, the rotating shaft 112, and the eccentric shaft 113 are all cylindrical. The centers of the grip 111 and the rotation shaft 112 are aligned. The radius of the eccentric shaft 113 is ½ of the radius of the rotating shaft 112. Further, the center of the eccentric shaft 113 is deviated from the center of the rotating shaft 112 by the radius of the eccentric shaft 113. The rotating shaft 112 is inserted into the bearing hole 99, and the eccentric shaft 113 is fitted into the elongated hole 92 (see also FIG. 16).

FIG. 16 shows how the lens holder 90 is moved in the optical axis OA direction by using the eccentric driver 110. When the eccentric driver 110 is rotated by 180 ° from the state shown in FIG. 16 (A) in which the eccentric shaft 113 is located at the center of the slotted hole 92 and the front surface of the lens holder 90 and the housing 91 coincide with each other, FIG. As shown in, the eccentric shaft 113 rotates 180 ° along the slot 92. As the eccentric shaft 113 rotates, the lens holder 90 protrudes from the front surface of the housing 91 by the diameter of the eccentric shaft 113.

As shown by the arrows in both directions, the lens holder 90 can transition between the state shown in FIG. 16 (A) and the state shown in FIG. 16 (B), and the eccentric axis with respect to the optical axis OA direction. It has an adjustment allowance for the diameter of 113.

The adjusting mechanism 81 is composed of a guide protrusion 93 that functions as a guide mechanism, a guide groove 97, an elongated hole 92 that functions as a moving mechanism, a fixing tool 100 that functions as a fixing mechanism, a screw 105, and a screw hole 106. The adjustment mechanism 82 has the same configuration as the adjustment mechanism 81 except that the adjustment target changes from the collimating lens 75 to the collimating lens 77, and therefore the illustration and description thereof will be omitted.

In FIG. 17, when the collimating lens 75 is moved in the optical axis OA direction by the adjusting mechanism 81, the focal position BFP of the blue light BL emitted from the condenser lens 80 changes. Specifically, when the collimating lens 75 moves toward the blue semiconductor light source 35 along the optical axis OA from the state shown in FIG. 17 (A), it emits light from the condenser lens 80 as shown in FIG. 17 (B). The focal length of the blue light BL is increased, and the focal position BFP is moved away from the condenser lens 80. On the contrary, when the collimating lens 75 moves to the opposite side of the blue semiconductor light source 35 along the optical axis OA from the state shown in FIG. 17 (A), it is emitted from the condenser lens 80 as shown in FIG. 17 (C). The focal distance of the blue light BL becomes shorter, and the focal position BFP approaches the condenser lens 80. In the present embodiment, the focal position BFP of the blue light BL emitted from the condenser lens 80 is adjusted by moving the collimating lens 75 in the optical axis OA direction by the adjusting mechanism 81 by utilizing such optical properties. .. In FIG. 17, the dichroic mirror 79 is not shown in order to avoid complication. Further, since the change in the focal position RFP of the red light RL by the adjusting mechanism 82 is the same as in the case of FIG. 17, the description thereof will be omitted.

In FIG. 18, the adjustment mechanism 81, 82 adjusts the focal position BFP of the blue light BL and the focal position RFP of the red light RL before the light source device 13 is shipped by using the detection unit 120.

The detection unit 120 includes a light guide 121 for detection, an incident end scanning device 122, a light amount waveform detection device 123, and a light amount waveform monitor 124. The detection light guide 121 has the same specifications as the light guide 55 mounted on the endoscope 11. A connector 126 similar to the light source connector 29B of the endoscope 11 is provided at the incident end 125 of the detection light guide 121, and the connector 126 is connected to the receptacle connector 54 of the light source device 13.

The incident end scanning device 122 reciprocates the incident end 125 of the detection light guide 121 in the optical axis OA direction at a predetermined scan width and time interval, and causes the condenser lens 80 and the incident end 125 in the light source device 13 to move back and forth. The positional relationship is changed periodically. For the scan width, for example, the tolerance of the distance between the condenser lens 80 and the incident end 61 of the light guide 55 in a plurality of endoscopes 11A to 11C of the same model is set.

The light amount waveform detection device 123 detects the light amount of each color light of blue light BL, green light GL, and red light RL emitted from the emission end of the detection light guide 121 at a predetermined timing, and detects each color light in the optical axis OA direction. Outputs a light intensity waveform indicating the light intensity.

The light amount waveform monitor 124 displays the light amount waveform of each color light output from the light amount waveform detection device 123 (light amount waveform GW of green light GL in FIG. 18).

The horizontal axis of the light amount waveform is assigned the position on the optical axis OA, and the vertical axis is assigned the light intensity. “0” on the horizontal axis indicates the center position of the scan width of the incident end 125 by the incident end scanning device 122. The horizontal axis indicates the position away from the condenser lens 80 as it goes to the minus side on the left side.

In FIG. 18, the tolerance of the distance between the condenser lens 80 and the incident end 61 of the light guide 55 in a plurality of endoscopes 11A to 11C of the same model is, for example, 1.5 mm, and the incident end 125 by the incident end scanning device 122. The scan width of is set to -1.5 mm to 1.5 mm.

Hereinafter, the operation of the above configuration will be described. First, the assembly work of the light source device 13 such as fitting the lens holder 90 into the fitting hole 95 is performed. After the assembly work, the focal positions of the blue light BL and the red light RL emitted from the condenser lens 80 are adjusted to eliminate the color shift to match the focal positions of the blue light BL, the green light GL, and the red light RL. A final inspection before shipment, including work, is performed.

In the color shift elimination work, first, the connector 126 provided at the incident end 125 of the detection light guide 121 of the detection unit 120 is connected to the receptacle connector 54 of the light source device 13.

Then, the incident end scanning device 122, the light amount waveform detection device 123, and the light amount waveform monitor 124 of the detection unit 120 are driven. As a result, the incident end 125 of the detection light guide 121 is reciprocated in the optical axis OA direction by the incident end scanning device 122 at a predetermined scan width and time interval. Further, the light amount waveform detection device 123 detects the light amount of the light emitted from the emission end of the detection light guide 121 at a predetermined timing, and the light amount waveform which is the detection result is displayed on the light amount waveform monitor 124.

The operator observes the light amount waveform displayed on the light amount waveform monitor 124, and the peak of the light amount waveform GW indicating the focal position GFP of the green light GL and the peak of the light amount waveform BW indicating the focal position BFP of the blue light BL. The adjustment mechanisms 81 and 82 adjust the positions of the collimating lenses 75 and 77 on the optical axis OA so that the peaks of the light amount waveform RW indicating the focal position RFP of the red light RL and the red light RL coincide with each other. More specifically, after inserting the rotating shaft 112 of the eccentric driver 110 into the bearing hole 99 and fitting the eccentric shaft 113 into the elongated hole 92, the eccentric driver 110 is rotated to rotate the collimating lenses 75 and 77 to the optical axis. Move in the OA direction.

Here, "matching the focal positions of the respective colored lights" includes, of course, the case where the focal positions of the respective colored lights are completely matched, but also includes the case where the focal positions of the respective colored lights are within a predetermined range. This predetermined range is represented by a line segment indicated by reference numeral 128 in FIG. The operator more preferably completes the peaks of the light intensity waveforms GW, BW, and RW of each color light so that the peaks of the light intensity waveforms GW, BW, and RW of each color light are at least within the predetermined range indicated by the line segment 128. Adjust to match.

In the position adjustment, while observing the light amount waveform displayed on the light amount waveform monitor 124, the eccentric driver 110 is rotated to match the peaks of the light amount waveforms BW and RW with the peaks of the light amount waveform GW, and the collimating lenses 75 and 77 are optical axes. It may be moved in the OA direction, and the focal positions of the blue light BL, the green light GL, and the red light RL can be matched very easily.

Further, the adjustment mechanisms 81 and 82 are provided only on the collimating lenses 75 and 77, and the focal position BFP of the blue light BL and the focal position RFP of the red light RL are set to the focal position of the green light GL with the focal position GFP of the green light GL as a reference. Since each of the collimating lenses is matched with the GFP, an adjustment mechanism is provided for each of the collimating lenses 75 to 77, and the adjustment work can be saved as compared with the case of adjusting the focal position of each of the three colors of light.

Of course, the collimating lens 76 may be provided with the same adjustment mechanism as the adjustment mechanisms 81 and 82. When the collimating lens 76 is also provided with an adjustment mechanism, the position of one of the collimating lenses 75 to 77, for example, the collimating lens 76 is first adjusted in the color shift elimination work, and the peak of the light amount waveform GW is maximized. The position of the collimating lens 76 is searched. Then, after fixing the collimating lens 76 to the searched position, the positions of the collimating lenses 75 and 77 may be adjusted.

The adjusting mechanisms 81 and 82 have a simple configuration of a guide protrusion 93 as a guide mechanism, a guide groove 97, an elongated hole 92 as a moving mechanism, a fixing tool 100 as a fixing mechanism, a screw 105, and a screw hole 106. Therefore, it is possible to minimize the increase in size and cost of the light source device 13 by providing the adjustment mechanisms 81 and 82.

After moving the collimating lenses 75 and 77 toward the optical axis OA to match the focal positions of the blue light BL, the green light GL, and the red light RL, the operator screwed the screw 105 into the screw hole 106. Then, the fixture 100 is fastened and fixed to the housing 91, and the positions of the collimating lenses 75 and 77 are fixed. This completes the color shift elimination work.

After the final inspection including the color shift eliminating work is completed, the light source device 13 is shipped to the customer.

When performing endoscopic diagnosis in a medical field, the endoscope 11 is connected to the processor device 12 and the light source device 13, the power of the processor device 12 and the light source device 13 is turned on, and the endoscope system 10 is started. ..

The insertion portion 16 of the endoscope 11 is inserted into the living body, and observation in the living body is started. The light source control unit 42 sets the drive current value given to each of the LEDs 43 to 45, and starts lighting each of the semiconductor light sources 35 to 37. Then, the amount of light is controlled while maintaining the target emission spectrum.

Each of the semiconductor light sources 35 to 37 emits blue light BL, green light GL, and red light RL by the LEDs 43 to 45, respectively. The blue light BL, the green light GL, and the red light RL are incident on the collimating lenses 75 to 77 of the optical system group 41, respectively.

The blue light BL is reflected by the dichroic mirror 79. The green light GL passes through the dichroic mirrors 78 and 79. The red light RL is reflected by the dichroic mirror 78 and passes through the dichroic mirror 79. The optical paths of blue light BL, green light GL, and red light RL are coupled by the dichroic mirrors 78 and 79. These blue light BL, green light GL, and red light RL are incident on the condenser lens 80. As a result, a white light WL composed of a mixed light of blue light BL, green light GL, and red light RL is generated. The condenser lens 80 concentrates the white light WL on the incident end 61 of the light guide 55 of the endoscope 11 and supplies the white light WL to the endoscope 11.

In the endoscope 11, the white light WL is guided to the illumination window 22 through the light guide 55 and is irradiated to the observation target from the illumination window 22. The reflected light of the white light WL reflected by the observation target is incident on the image pickup sensor 56 from the observation window 23. The image pickup sensor 56 outputs a B image signal, a G image signal, and an R image signal to the DSP 66 of the processor device 12. The DSP 66 color-separates each image signal and inputs it to the image processing unit 67. The image pickup operation by the image pickup sensor 56 is repeated at a predetermined frame rate. The image processing unit 67 generates a display image based on each input image signal. The display image is output to the monitor 14 through the display control unit 69. The displayed image is updated according to the frame rate of the image pickup sensor 56.

Further, the DSP 66 calculates an exposure value based on each image signal, and transmits an exposure control signal corresponding to the calculated exposure value to the light source control unit 42 of the light source device 13. The light source control unit 42 determines the drive current values of the semiconductor light sources 35 to 37 so that the ratio of the amount of light of each color light becomes constant (so that the target emission spectrum does not change) based on the received exposure control signal. .. Then, each semiconductor light source 35 to 37 is driven by the determined drive current value. As a result, the amount of blue light BL, green light GL, and red light RL constituting the white light WL by each of the semiconductor light sources 35 to 37 can be kept constant at a ratio suitable for observation.

As shown in FIG. 19, if the color shift eliminating work is not performed and the light source device 13 is shipped with the shifts of the focal positions BFP, GFP, and RFP similar to those in FIG. 25, the light source device 13 is also described in FIG. As you can see, the color of the displayed image changes. For example, even in the endoscopes 11A to 11C of the same model, the positional relationship between the condenser lens 80 and the incident end 61 changes depending on individual differences. When the incident end 61A is at the focal position RFP of the red light RL as in the light guide 55A of the endoscope 11A, the display image 130R having a reddish color is generated as a whole. Further, when the incident end 61B is at the focal position GFP of the green light GL as in the light guide 55B of the endoscope 11B, a display image 130G having a greenish color as a whole is generated, and the light of the endoscope 11C is generated. When the incident end 61C is located at the focal position BFP of the blue light BL as in the guide 55C, the display image 130B having a bluish tint as a whole is generated. Although not shown, the endoscopes 11D and 11E have different specifications when the positional relationship between the condenser lens 80 and the incident end 61 is different from each other. The color of the displayed image changes with.

On the other hand, in the present embodiment, as shown in FIG. 20, the focal positions BFP, GFP, and RFP of the blue light BL, the green light GL, and the red light RL are the same due to the color shift elimination work, so that the same model is used. Even if the positional relationship between the condenser lens 80 and the incident ends 61A, 61B, 61C changes due to individual differences in the endoscopes 11A to 11C, the light amount balance of each color light incident on the incident ends 61A, 61B, 61C fluctuates. As a result, the display image 130 in which the color tone does not change is generated. Although not shown, the same applies to the case where a plurality of types of endoscopes 11D and 11E having different specifications are used. Therefore, the color of the displayed image does not change every time the endoscopic diagnosis is made, and the operator can smoothly perform the endoscopic diagnosis without feeling any discomfort.

When the semiconductor light sources 35 to 37 are used, since the semiconductor light sources 35 to 37 having a rectangular light emitting portion are used, the condensed image of each color light emitted from the condenser lens 80 is also rectangular. In such a case, a semiconductor light source having a circular light emitting portion is used, and the condensed image of each color light is more likely to protrude from the incident end 61 than in the case where the condensed image is circular. Therefore, the adjustment mechanisms 81 and 82 of the present invention are particularly useful in the light source device 13 having the semiconductor light sources 35 to 37 having such a rectangular light emitting portion.

In the above embodiment, the collimating lenses 75 and 77 are provided with the adjusting mechanisms 81 and 82, but the adjusting mechanism is more suitable than the dichroic mirrors 78 and 79 in the optical path from the semiconductor light sources 35 to 37 to the condenser lens 80. It may be provided on the semiconductor light source 35 to 37 side. For example, as shown in FIGS. 21 and 22, adjustment mechanisms 131 and 132 may be provided in the blue semiconductor light source 35 and the red semiconductor light source 37 in place of or in addition to the collimating lenses 75 and 77. In this case, the adjustment mechanisms 131 and 132 move the blue semiconductor light source 35 and the red semiconductor light source 37 in the optical axis OA direction. As shown in FIG. 22, when the adjusting mechanism is provided in the blue semiconductor light source 35 and the red semiconductor light source 37 in addition to the collimating lenses 75 and 77, only the collimating lenses 75 and 77 or the blue semiconductor light source 35 and red in FIG. 21 are provided. It is possible to earn an adjustment allowance as compared with the case of using only the semiconductor light source 37.

However, unlike the collimating lens, the semiconductor light source is connected to a member such as a wiring that is likely to hinder the movement in the optical axis OA direction. Therefore, the semiconductor light source is not provided with an adjustment mechanism as in the above embodiment. It is preferable to provide an adjustment mechanism only on the collimating lens and move the collimating lens in the optical axis OA direction to match the focal positions of the light of each color.

In the above embodiment, the example in which one collimating lens 75 to 77 constitutes the first optical system has been described, but the first optical system may be composed of a plurality of optical members. Similarly, the second optical system may be composed of a plurality of optical members instead of the one condenser lens 80 exemplified in the above embodiment. When the first optical system is composed of a plurality of optical members, an adjusting mechanism may be provided in at least one of the plurality of optical members.

In the above embodiment, the focal position BFP of the blue light BL and the focal position RFP of the red light RL are matched with the focal position GFP of the green light GL with reference to the focal position GFP of the green light GL. The focal position BFP of, or the focal position RFP of red light RL may be used as a reference. When the focal position BFP of the blue light BL is used as a reference, the collimating lenses 76 and 77 are provided with an adjusting mechanism, but the collimating lens 75 may or may not be provided with an adjusting mechanism. When the focal position RFP of the red light RL is used as a reference, the collimating lenses 75 and 76 are provided with an adjusting mechanism, but the collimating lens 77 may or may not be provided with an adjusting mechanism.

In the above embodiment, it has been described that the color shift eliminating work is performed at the time of the final inspection before shipment of the light source device 13, but the time of performing the color shift eliminating work is not particularly limited. For example, after the light source device 13 is shipped, a worker may go to the customer with the detection unit 120 to perform color shift elimination work at the request of the customer.

The adjusting mechanism is not limited to the configuration exemplified in the above embodiment. For example, the guide mechanism can be configured by the lens holder 90 and the fitting hole 95 itself without providing the guide protrusion 93 and the guide groove 97 of the above embodiment. Further, as the moving mechanism, instead of the slotted hole 92 of the above embodiment, a well-known moving mechanism such as a ball screw, a push-pull bolt, an eccentric cam, or the like that converts a rotary motion into a straight motion may be used. Further, the fixing mechanism may also be composed of a pair of C-rings that sandwich the lens holder 90 from both sides and a screw that fastens and fixes the pair of C-rings. In short, any mechanism can be used as long as it is possible to guide the movement of the optical member such as the collimating lens 75 in the optical axis OA direction, move the optical member in the optical axis direction, and fix the position of the optical member. good.

In the above embodiment, three semiconductor light sources 35 to 37 of blue, green, and red are exemplified as monochromatic semiconductor light sources, but as shown in FIG. 23, a purple wavelength band for emphasizing and observing surface blood vessels. A purple semiconductor light source 135 that emits light (purple light VL) may be added.

In FIG. 23, the purple semiconductor light source 135 has a purple LED (not shown) that emits purple light VL as a light emitting element. The specific structure of the purple semiconductor light source 135 is the same as that of the blue semiconductor light source 35 shown in FIGS. 5 and 6. As shown in FIG. 24, the purple semiconductor light source 135 has a wavelength component in the vicinity of, for example, 380 nm to 420 nm, which is a purple wavelength band, and emits purple light VL having a center wavelength of 405 ± 10 nm and a half width of 20 ± 10 nm.

The optical system group 136 includes a collimating lens 137 that transmits purple light VL to make it substantially parallel light, and a dichroic mirror 138 that combines the optical paths of blue light BL and purple light VL in the optical system group 41 of the above embodiment. This is the added configuration. The blue semiconductor light source 35 and the purple semiconductor light source 135 are arranged so that their optical axes are orthogonal to each other, and a dichroic mirror 138 is provided at a position where these optical axes are orthogonal to each other. The dichroic mirror 138 is arranged at an angle of 45 ° with respect to the optical axes of the blue semiconductor light source 35 and the purple semiconductor light source 135.

The dichroic filter of the dichroic mirror 138 has a property of reflecting light in a purple wavelength band of, for example, less than about 430 nm and transmitting light in a wavelength band of blue, green, or red. The dichroic mirror 138 transmits the blue light BL from the blue semiconductor light source 35 to the downstream side and reflects the purple light VL from the purple semiconductor light source 135. As a result, the optical paths of the blue light BL and the purple light VL are combined. The purple light VL reflected by the dichroic mirror 138 has the characteristic that the dichroic mirror 79 reflects light in the blue wavelength band of less than about 480 nm as described above, so that the light is reflected by the dichroic mirror 79 and directed toward the condenser lens 80. .. As a result, all the optical paths of the blue light BL, the green light GL, the red light RL, and the purple light VL are combined.

The collimating lens 137 is provided with an adjusting mechanism 139, similarly to the collimating lenses 75 and 77 of the above embodiment. The adjusting mechanism 139 moves the collimating lens 137 toward the optical axis OA to match the focal position of the purple light VL with the focal positions of the blue light BL, the green light GL, and the red light RL.

As is well known, the reflectance of superficial blood vessels drops significantly in the wavelength band below 450 nm, and drops most in the vicinity of 405 nm. When the observation target is irradiated with light in a wavelength band having a low reflectance, absorption is large in the blood vessel, so that a display image having a difference in contrast between the blood vessel and the other portion can be obtained.

In addition, the scattering characteristics of light in living tissues also have a wavelength dependence, and the shorter the wavelength, the larger the scattering coefficient. Scattering affects the depth of light penetration into living tissue. That is, the larger the scattering, the more light is reflected near the mucosal surface layer of the living tissue, and the less light reaches the mesopelagic zone. Therefore, the shorter the wavelength, the lower the depth of penetration, and the longer the wavelength, the higher the depth of penetration.

The purple light VL with a central wavelength of 405 ± 10 nm emitted by the purple semiconductor light source 135 has a relatively short wavelength and a low invasion depth, so that it is largely absorbed by the surface blood vessels. Therefore, purple light VL can be used as special light for enhancing surface blood vessels. By using the purple light VL, it is possible to obtain a display image in which the surface blood vessels are visualized with high contrast.

When observing the surface blood vessels with emphasis, the purple semiconductor light source 135 is turned on in addition to the semiconductor light sources 35 to 37 in accordance with the timing of the accumulation operation of the image pickup sensor 56. When the semiconductor light sources 35 to 37 and 135 are turned on, purple light VL is added to the white light WL of the above embodiment, and the mixed light (WL + VL) thereof is irradiated to the observation target as illumination light.

The illumination light to which the purple light VL is added to the white light WL is separated by the micro color filter of the image pickup sensor 56. The B pixel receives the reflected light corresponding to the purple light VL in addition to the reflected light corresponding to the blue light BL. The G pixel and the R pixel receive the reflected light corresponding to the green light GL and the reflected light corresponding to the red light RL, respectively, as in the above embodiment. The image pickup sensor 56 sequentially outputs the B, G, and R image signals according to the frame rate according to the read timing.

In this case, the B image signal contains a component of the reflected light corresponding to the violet light VL in addition to the component of the reflected light corresponding to the blue light BL constituting the white light WL, so that the surface blood vessel is high. It is depicted in contrast. In lesions such as cancer, the pattern of superficial blood vessels tends to be higher than that of normal tissue, and the pattern of superficial blood vessels is characteristic. Therefore, the superficial blood vessels can be clearly visualized by adding a purple semiconductor light source 135. This is preferable because it makes it easier to identify the lesion.

In the above embodiment, the amount of light of each color light is controlled by changing the drive current value given to each LED 43 to 45 based on the exposure control signal from the processor device 12, but the influence of heat generation of the LED and deterioration with time are performed. The output light amount of the semiconductor light source may fluctuate with respect to the drive current value due to the influence of. Therefore, a light amount measurement sensor for measuring the light amount of each color light is provided in the optical system group, and it is monitored whether or not the light amount of each color light reaches the target value based on the light amount measurement signal output by the light amount measurement sensor. You may.

In this case, the light source control unit compares the light amount measurement signal with the target light amount, and based on the comparison result, gives each semiconductor light source 35 to 37 set by the exposure control so that the light amount becomes the target value. Fine-tune the drive current value. In this way, the light amount of each color light is constantly monitored by the light amount measurement sensor, and the drive current value given based on the measurement result of the light amount is finely adjusted, so that the light amount can always be controlled so as to be in line with the target value. Therefore, the illumination light of the target emission spectrum can be obtained more stably.

In the above embodiment, a semiconductor light source composed of only LEDs is mentioned. For example, a green semiconductor light source is excited by a blue excitation light LED that emits blue excitation light in a wavelength band from purple to blue, and a blue excitation light. It may be a fluorescent semiconductor light source composed of a green phosphor that emits green light in the green wavelength band. Further, in place of or in addition to the green semiconductor light source, the red semiconductor light source is excited by a blue excitation light LED that emits blue excitation light in the purple to blue wavelength band, and red fluorescence in the red wavelength band that is excited by the blue excitation light. It may be composed of a red phosphor that emits light. When the red semiconductor light source is composed of a fluorescent semiconductor light source, the excitation light LED is not limited to a blue excitation light emitting element that emits blue excitation light in the purple to blue wavelength band, but green that emits green excitation light in the green wavelength band. It may be an excitation light emitting element. In this case, a fluorescent material is enclosed in the cavity 76 shown in FIGS. 5 and 6 instead of the resin 78 to form a fluorescent semiconductor light source.

Further, the mounting form of the LED shown in FIGS. 5 and 6 is an example, and other forms may be adopted. For example, a microlens for adjusting the divergence angle may be provided on the light emitting surface of the resin 78, or the LED may be housed in a bullet-shaped case in which the microlens is formed instead of the surface mount type. When a fluorescent semiconductor light source is used as the green semiconductor light source or the red semiconductor light source, the fluorescent semiconductor light source is not limited to the one in which the excitation light LED and the phosphor are integrally provided, and may be provided separately. .. In this case, a light guide member such as a lens or an optical fiber is added between the excitation light LED and the phosphor, and the excitation light of the excitation light LED is guided to the phosphor via the light guide member.

Further, as the light emitting element, an organic EL (Electro-Luminescence) element may be used instead of the LED.

The configuration of the optical system group in the above embodiment is an example, and various changes can be made. For example, as an optical member constituting the third optical system, a dichroic mirror having a dichroic filter formed on a transparent glass plate is used, but a dichroic prism having a dichroic filter formed on a prism may be used instead. Further, instead of an optical member having a dichroic filter such as a dichroic mirror or a dichroic prism, for example, a plurality of incident ends facing each semiconductor light source and one emitting end facing the incident end of the light guide of the endoscope. The optical path may be coupled using a bifurcated light guide with. In the branched light guide, an optical fiber is divided into a plurality of optical fibers at one end by a predetermined number, and the incident end is branched into a plurality of pieces. In this case, each semiconductor light source is arranged so as to correspond to each of the branched incident ends.

In the above embodiment, the light source device 13 having three monochromatic semiconductor light sources 35 to 37 or four monochromatic semiconductor light sources 35 to 37 and 135 has been exemplified, but a blue semiconductor light source and a green semiconductor light source, and a green semiconductor light source and a purple semiconductor light source have been exemplified. The present invention can also be applied to a light source device having two monochromatic semiconductor light sources. The observation target may be irradiated with a mixed light of blue light BL and green light GL or a mixed light of green light GL and purple light VL to acquire a green light GL-based display image.

In the above embodiment, as the image pickup sensor 56, a color image pickup sensor that color-separates the illumination light by a micro color filter of B, G, and R is exemplified, and each image signal of B, G, and R is simultaneously acquired by the color image pickup sensor. The simultaneous endoscope system and the light source device used for the simultaneous endoscope system have been described as an example, but each image signal of B, G, and R is described by sequentially irradiating each color light of blue, green, and red with a monochrome image pickup sensor. The present invention may be applied to a surface-sequential endoscope system and a light source device used therein.

In the above embodiment, the example in which the light source device and the processor device are configured separately has been described, but these devices may be integrally configured. Further, the present invention is an endoscopic system using a fiber scope that guides the reflected light of the observation target of the illumination light with an image guide, and an ultrasonic endoscope having an image sensor and an ultrasonic transducer built in at the tip. And it can also be applied to the light source device used for it.

10 Endoscope system 11, 11A to 11E Endoscope 13 Light source device 35 Blue semiconductor light source 36 Green semiconductor light source 37 Red semiconductor light source 55, 55A to 55C Light guide 61, 61A to 61C Incident end 75 to 77, 137 Collimated lens ( 1st optical system, optical member)
78, 79, 138 Dichroic mirror (third optical system)
80 Condensing lens (second optical system)
81, 82, 139 Adjustment mechanism 92 Long hole 93 Guide protrusion 97 Guide groove 100 Fixture 105 Screw 106 Screw hole 110 Eccentric driver 120 Detection unit 135 Purple semiconductor light source BL Blue light GL Green light RL Red light WL White light VL Purple light BFP Focus position of blue light GFP Focus position of green light RFP Focus position of red light BW Light amount waveform of blue light GW Light amount waveform of green light RW Light amount waveform of red light

Claims (5)

The light source device for an endoscope that supplies illumination light to the light guide of the endoscope is composed of a plurality of monochromatic semiconductor light sources that emit light of a plurality of colors as the illumination light, and at least one optical member, and the plurality of monochromatic colors. A plurality of first optical systems that transmit the light of the plurality of colors from the semiconductor light source, and a second optical system that collects the light of the plurality of colors transmitted through the plurality of first optical systems to the incident end of the light guide. In the case of providing a system and a position adjusting mechanism for adjusting the position of the optical member in the optical axis direction of the first optical system.
Using a guide mechanism and a moving mechanism, a moving step of moving the lens holder holding the optical member in the optical axis direction so that the peaks of the light amount waveforms of the light quantities indicating the focal positions of the colored lights match.
A position adjusting method including a fixing step of pressing the lens holder by a fixing mechanism to fix the position of the optical member in the lens holder. The position adjusting method according to claim 1, wherein the moving mechanism moves the lens holder in the optical axis direction by converting a rotary motion into a straight motion. The lens holder is provided with an elongated hole.
In the movement step, the eccentric shaft of the eccentric driver is fitted into the slotted hole, and the rotational motion is applied to the eccentric driver to rotate the eccentric shaft along the slotted hole to rotate the lens holder. The position adjusting method according to claim 2, wherein the lens is moved in the direction of the optical axis by the straight motion. In the fixing step, the position of the optical member is fixed by using a fixture.
The position adjusting method according to claim 3, wherein the fixture covers a bearing hole through which the eccentric shaft is inserted. The position adjusting method according to any one of claims 1 to 4, wherein in the fixing step, the lens holder is pressed from a direction intersecting the optical axis direction by the fixing mechanism.

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