JP7290770B2 - Position adjustment method - Google Patents

Description

The present invention relates to a position adjustment method performed in an endoscope light source device that supplies illumination light to an endoscope.

In the medical field, endoscopic diagnosis using an endoscopic system is actively performed. An endoscope system includes an endoscope, a processor device that processes image signals output by the endoscope, and an endoscope light source device (hereinafter simply referred to as a light source device) that supplies illumination light to the endoscope. It has

An endoscope has an insertion section that is inserted into a living body, and an illumination window for irradiating an observation target with illumination light and an observation window for capturing an image of the observation target are arranged at the distal end of the insertion section. there is The endoscope incorporates a light guide made up 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 inside the light source device, and the exit end of the light guide through which the illumination light is emitted is arranged behind the illumination window.

An imaging sensor such as a CCD (Charge Coupled Device) image sensor is arranged behind the observation window. The imaging sensor captures an image of 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.

After the endoscope diagnosis is completed, the endoscope is removed from the processor unit and the light source unit and cleaned and disinfected. Then, when the next endoscopic diagnosis is started, the connection is made to the processor device and the light source device again. In medical practice, there are multiple endoscopes of the same model, or multiple types of endoscopes with specifications according to the details of endoscopic diagnosis. A plurality of endoscopes and a plurality of 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 for a light source device. A light source device using a semiconductor light source having a light emitting element such as a light source has been proposed (see Patent Document 1).

Patent Document 1 describes a light source device that includes blue, green, and red semiconductor light sources that emit three colors of blue, green, 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 the blue, green, and red semiconductor light sources, respectively. The second optical system converges the 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 transmitted through the first optical system.

JP 2015-047402 A

In a light source device that supplies light of a plurality of colors from a plurality of monochromatic semiconductor light sources as illumination light, as in Patent Document 1, all of the light of a plurality of colors emitted from the second optical system is emitted from the incident end of the light guide. Strictly speaking, it is ideal to have a configuration in which the light is focused at 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 broken lines), green light GL (indicated by thick solid lines), and red light RL (thin (indicated by solid lines) may deviate from each other on the optical axis OA, causing so-called color misregistration in which the color tone of the displayed image changes.

Factors that cause each focal position to shift include assembly errors and individual differences in the components that supply the illumination light, such as the blue, green, and red semiconductor light sources, and the first to third optical systems. For example, if the gap between the blue semiconductor light source and the first optical system that transmits the blue light BL is displaced due to an assembly error, the focus position BFP of the blue light BL is also displaced. Alternatively, if the wavelength range or center wavelength of the red light RL shifts 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 will change. deviate.

When each focal position shifts, the light amount waveforms BW (indicated by broken lines), GW (indicated by thick solid lines), and RW (indicated by thin solid lines) represent the light amounts on the optical axis OA of the three colors of light BL, GL, and RL in FIG. ), 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 amount waveform is a mountain-shaped waveform that peaks at the focal position and drops symmetrically before and after the focal position. Further, each light amount waveform BW, GW, RW has substantially the same shape.

If the peaks of the light intensity waveforms BW, GW, and RW shift, the light intensity balance of the three colors of light BL, GL, and RL fluctuates depending on the distance from the second optical system 200 . For example, at the focal position RFP of the red light RL, the light intensity of the red light RL is the highest, followed by the green light GL and the blue light BL in order of decreasing light intensity. Conversely, at the focal position BFP of the blue light BL, the light quantity of the blue light BL is the highest, followed by the green light GL and the red light RL in order of decreasing light quantity.

In such a case, depending on the positional relationship between the second optical system 200 and the incident end 202 of the light guide 201, the balance of the light amounts of the three colors of light BL, GL, and RL incident on the incident end 202 varies, resulting in a display image. Color misregistration in which the tint changes occurs. 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 green light GL has the highest amount of light, so the illumination light becomes greenish, 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 displayed image 203R is entirely reddish, and the incident end 202C is blue as in the light guide 201C. If it is at the focal position BFP of the light BL, a display image 203B that is entirely bluish is generated.

As described above, the endoscope is detached from or connected to the light source device each time an endoscope diagnosis is performed. Further, when a single light source device is shared by a plurality of endoscopes of the same model, the second optical system 200 and the incident end 202 may be different due to individual differences among the endoscopes, even though they are of the same model. The positional relationship with changes. Furthermore, when a plurality of types of endoscopes having different specifications are shared by one light source device, some of the plurality of types of endoscopes have different positional relationships between the second optical system 200 and the incident end 202. exist. For this reason, the positional relationship between the second optical system 200 and the entrance end 202 is not always the same, and varies depending on the connection condition to the light source device, individual differences of endoscopes, and specifications. Therefore, if there is a shift in the focal position of each of the lights of a plurality of colors, a situation may occur in which the color of the displayed image changes each time an endoscopic diagnosis is performed.

Since endoscopic diagnosis is performed based on subtle changes in color of an object to be observed, it is very important to reduce changes in color of displayed images each time endoscopic diagnosis is performed. However, if the color tone of the displayed image changes each time an endoscopic diagnosis occurs as described above, the operator feels uncomfortable, making it difficult to perform an endoscopic diagnosis.

The present invention provides a position adjustment method capable of reducing changes in color of a displayed image each time an endoscopic diagnosis is performed when a plurality of monochromatic semiconductor light sources that emit light of a plurality of colors are used. With the goal.

In the position adjustment method of the present invention, an endoscope light source device that supplies illumination light to a light guide of an endoscope includes a plurality of monochromatic semiconductor light sources each emitting light of a plurality of colors as illumination light, and at least one optical member. a plurality of first optical systems configured to transmit light of a plurality of colors from a plurality of monochromatic semiconductor light sources, respectively; 2 optical system, and a position adjustment mechanism for adjusting the position of the optical member in the optical axis direction of the first optical system , and in the case where it can be connected to a detection unit having a light guide for detection , the guide mechanism and the moving mechanism When the position of the incident end of the light guide for detection is moved in the optical axis direction using the It has a moving step of moving a lens holder holding the optical member in the optical axis direction so as to match, and a fixing step of pressing the lens holder by a fixing mechanism to fix the position of the optical member in the lens holder.

Preferably, the moving mechanism moves the lens holder in the optical axis direction by converting rotational motion into linear motion. An elongated hole is provided in the lens holder, and in the moving step, the eccentric shaft of the eccentric driver is fitted into the elongated hole, and the eccentric shaft is rotated along the elongated hole by giving rotational motion to the eccentric driver. Preferably, the lens holder is moved in the direction of the optical axis by linear motion. Preferably, in the fixing step, the position of the optical member is fixed using a fixing tool, and the fixing tool presses the upper part of the lens holder . In the fixing step, the fixing mechanism preferably presses the lens holder from a direction intersecting the optical axis direction.

Advantageous Effects of Invention According to the present invention, it is possible to reduce the change in color of a displayed image each time an endoscopic diagnosis is performed.

1 is an external view of an endoscope system; FIG. It is a front view of the tip part of an endoscope. 1 is an explanatory diagram of an endoscope system in which a single processor device and light source device are shared by a plurality of endoscopes; FIG. 1 is a block diagram of an endoscope system; FIG. 1 is a cross-sectional view showing a blue semiconductor light source; FIG. FIG. 4 is a plan view showing a blue semiconductor light source; 4 is a graph showing an emission spectrum of blue light emitted by a blue semiconductor light source; 4 is a graph showing an emission spectrum of green light emitted by a green semiconductor light source; 4 is a graph showing an emission spectrum of red light emitted by a red semiconductor light source; 4 is a graph showing emission spectra of white light composed of blue light, green light, and red light. 4 is a graph showing spectral characteristics of a micro color filter of an image sensor; FIG. 4 is an explanatory diagram showing timings of irradiation of white light and operation timings of an imaging sensor; 3 is a diagram showing the arrangement of semiconductor light sources and the detailed configuration of an optical system group; FIG. 3 is an exploded perspective view of the lens holder and housing; FIG. FIG. 10 is a perspective view of the lens holder, housing, and eccentric driver; FIG. 10 is an explanatory view showing how the lens holder is moved in the optical axis direction using an eccentric driver while the lens holder is temporarily fixed to the housing. FIG. 10 is an explanatory diagram showing a change in focal position due to movement of the collimating lens in the optical axis direction; Fig. 3 is a block diagram of a detection unit; FIG. 10 is an explanatory diagram showing the relationship between the position of the incident end of the light guide and the displayed image when the focal positions of blue light, green light, and red light are shifted; FIG. 10 is an explanatory diagram showing the relationship between the position of the incident end of the light guide and the displayed image when the focal positions of blue light, green light, and red light match. FIG. 10 is a diagram showing the arrangement of the semiconductor light sources and the detailed configuration of the optical system group when adjusting mechanisms are provided for the blue semiconductor light source and the red semiconductor light source instead of the collimator lens; FIG. 10 is a diagram showing the arrangement of the semiconductor light sources and the detailed configuration of the optical system group when adjusting mechanisms are provided for the blue semiconductor light source and the red semiconductor light source in addition to the collimating lens; It is a figure which shows the arrangement|positioning of each semiconductor light source when a violet semiconductor light source is added, and the detailed structure of an optical system group. 4 is a graph showing an emission spectrum of violet light emitted by a violet semiconductor light source; FIG. 10 is an explanatory diagram showing the relationship between the position of the incident end of the light guide and the displayed image when the focal positions of blue light, green light, and red light are shifted in the conventional light source device.

In FIG. 1, an endoscope system 10 includes an endoscope 11 that captures an image of 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 imaging, and an observation target. and a light source device 13 for supplying illumination light to the endoscope 11 to irradiate the endoscope. The processor unit 12 is connected to a monitor 14 for displaying display images and an operation input unit 15 such as a keyboard and a mouse.

The endoscope 11 includes an insertion portion 16 to be inserted into a living body, an operation portion 17 provided at a proximal end portion of the insertion portion 16, and a universal cord connecting the endoscope 11, the processor device 12, and the light source device 13. 18.

The insertion portion 16 is composed of a distal end portion 19, a bending portion 20, and a flexible tube portion 21, which are connected in order from the distal end. As shown in FIG. 2, the distal end surface of the distal end portion 19 is provided with an illumination window 22 for irradiating an observation target with illumination light, an observation window 23 for capturing an image of the observation target, and a feeder for cleaning the observation window 23 . An air/water nozzle 24 for supplying air and water, and a forceps outlet 25 for performing various treatments by protruding treatment tools such as forceps and an electric scalpel are provided. Behind the observation window 23, an imaging sensor 56 and an objective optical system 63 for imaging (both of which are shown in FIG. 4) are incorporated.

The bending section 20 is composed of a plurality of connected bending pieces, and bends vertically and horizontally by operating the angle knob 26 of the operation section 17 . In FIG. 1, the bending motion in the upward direction is indicated by dashed lines. By bending the bending portion 20, the tip portion 19 is oriented in a desired direction. The flexible tube portion 21 is flexible so that it can be inserted into tortuous ducts such as the esophagus and intestines. The insertion portion 16 includes a communication cable for communicating a drive signal for driving the imaging sensor 56 and an image signal output by the imaging sensor 56, and a light guide 55 for guiding illumination light supplied from the light source device 13 to the illumination window 22 ( 4) are inserted.

The operation unit 17 includes an amble knob 26, a forceps port 27 for inserting a treatment instrument, an air/water supply button 28 operated when air/water is supplied from the air/water supply nozzle 24, and a still image. A release button (not shown) and the like for photographing are provided.

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

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

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

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

Each of the semiconductor light sources 35 to 37 includes, as light emitting elements, a blue LED 43 that emits light in a blue wavelength band (blue light BL), a green LED 44 that emits light in a green wavelength band (green light GL), and light in a red wavelength band. Each has a red LED 45 that emits (red light RL). Each of the LEDs 43-45 is formed by joining a P-type semiconductor and an N-type semiconductor, as is well known. Then, when a voltage is applied, electrons and holes recombine across the bandgap in the vicinity of the PN junction, current flows, and energy corresponding to the bandgap is emitted as light upon recombination. The amount of light emitted from each of the LEDs 43 to 45 increases or decreases according to an increase or decrease in power supply.

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

Under the control of the light source control unit 42, the drivers 50-52 continuously apply drive currents to the LEDs 43-45 to light the LEDs 43-45. By changing the value of the drive current to be applied according to the exposure control signal, the power supplied to each LED 43 to 45 is changed, and the light quantity of each color light of blue light BL, green light GL and red light RL is controlled respectively. do. PAM (Pulse Amplitude Modulation) control that changes the amplitude of the drive current pulse by applying the drive current not continuously but in the form of pulses, and PWM (Pulse Width Modulation) control that changes the duty ratio of the drive current pulse may be performed.

The optical system group 41 combines the optical paths of the blue light BL, the green light GL, and the red light RL into one optical path, and converges 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 contacts the outer peripheral surface of the light source connector 29B. A restricting member is provided to restrict the amount of insertion of the light source connector 29B into the receptacle connector 54 . Also, 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 imaging sensor 56 , an analog processing circuit 57 (AFE: Analog Front End), and an imaging controller 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 circumference of the fiber bundle 59 . When the light source connector 29</b>B is connected to the light source device 13 , the incident end 61 of the light guide 55 (fiber bundle 59 ) arranged at the light source connector 29</b>B faces the optical system group 41 . The output 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 illumination lens 62 is arranged behind the illumination window 22 . The illumination light supplied from the light source device 13 is guided by the light guide 55 to the illumination lens 62 and emitted from the illumination window 22 toward the observation target. The irradiation lens 62 consists of a concave lens and widens the divergence angle of the light emitted from the light guide 55 . This makes it possible to irradiate the illumination light over a wide range of the observation target.

Behind the observation window 23, an objective optical system 63 and an imaging sensor 56 are arranged. The image of the observation target enters the objective optical system 63 through the observation window 23 and is imaged on the imaging plane 56A of the imaging sensor 56 by the objective optical system 63 .

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

The AFE 57 consists of a correlated double sampling circuit, an automatic gain control circuit, and an analog/digital converter (all not shown). The correlated double sampling circuit performs correlated double sampling processing on the analog image signal from the imaging sensor 56 to remove noise caused by signal charge reset. An 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 imaging control unit 58 is connected to the controller 65 in the processor device 12 and inputs drive signals to the imaging sensor 56 in synchronization with the reference clock signal input from the controller 65 . The imaging sensor 56 outputs an image signal to the AFE 57 at a predetermined frame rate based on the driving signal from the imaging control section 58 .

The imaging sensor 56 is a color imaging sensor, and an imaging surface 56A is provided with micro color filters of three colors: 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 arrangement of each filter is, for example, a Bayer arrangement.

In the following description, a pixel assigned with a B filter is referred to as a B pixel, a pixel assigned with a G filter is referred to as a G pixel, and a pixel assigned with an R filter is referred to as an R pixel. An image signal output from a B pixel is called a B image signal, an image signal output from a G pixel is called a G image signal, and an image signal outputted from an R pixel is called an R image signal.

The processor device 12 includes a controller 65 , a DSP (Digital Signal Processor) 66 , an image processing section 67 , a frame memory 68 , and a display control section 69 . The controller 65 has a CPU (Central Processing Unit), a ROM (Read Only Memory) that stores control programs and setting data necessary for control, a RAM (Random Access Memory) that loads programs and functions as a working memory, and the like. , the CPU controls each part of the processor unit 12 by executing the control program.

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

Further, the DSP 66 calculates an exposure value based on each image signal, and increases the amount of illumination light when the amount of light for the entire image is insufficient (underexposure), and increases the amount of illumination light when the amount of light is too high. In (overexposure), an exposure control signal is output to the controller 65 for controlling the amount of illumination light to be reduced. The controller 65 transmits an exposure control signal to the light source control section 42 of the light source device 13 .

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

The image processing unit 67 generates a display image based on the B, G, and R image signals. This display image is output to the monitor 14 through the display control section 69 . The image processing unit 67 generates a display image each 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 having a cavity 76 for accommodating the blue LED 43, and a cavity 76. and a resin 78 encapsulated in the . Blue LED 43 is connected to substrate 75 by wiring 79 . Such a mounting form of the blue semiconductor light source 35 is generally called a surface mounting type.

The cavity 76 has a rectangular opening, and the width narrows toward the substrate 75 side. Blue light BL is emitted from the rectangular opening of this cavity 76 . That is, the opening of the cavity 76 functions as a light emitting portion for the blue light BL. Also, the inner surface of the cavity 76 functions as a reflector that reflects the blue light BL. The dimensions of the opening of the cavity 76 are, for example, a long side of 2 mm and a short side of 1.5 mm. A diffusion material for diffusing light is dispersed in the resin 78 . Since the semiconductor light sources 35 to 37 have 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 emits blue light BL having a wavelength component near 420 nm to 500 nm, which is the blue wavelength band, with 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 emits green light GL having a wavelength component in the vicinity of 480 nm to 600 nm, which is the wavelength band of green, for example, and 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 emits red light RL having a wavelength component in the vicinity of 600 nm to 650 nm, which is a red wavelength band, for example, and having a center wavelength of 625±10 nm and a half width of 20±10 nm. . Note that 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 the range of wavelengths indicating half of the peak of the emission spectrum of each color light.

FIG. 10 shows the emission spectrum of mixed light of blue light BL, green light GL, and red light RL whose optical paths are combined by the optical system group 41 . This mixed light is used as white light WL, which is illumination light. In order to maintain a color rendering property equivalent to that of the white light emitted by the xenon light source, the white light WL is designed so that its emission spectrum does not have a wavelength band without a light intensity component.

FIG. 11 is a graph showing spectral characteristics of the B filter, G filter, and R filter provided on the imaging surface 56A of the imaging sensor 56. As shown in FIG. A B pixel assigned with a B filter is sensitive to light in a wavelength band of about 380 nm to 560 nm, and a G pixel assigned with a G filter is sensitive to light in a wavelength band of about 450 nm to 630 nm. Also, the R pixel assigned with the R filter is sensitive to light in the wavelength band of approximately 580 nm to 800 nm. The blue light BL, the green light GL, and the red light RL forming the white light WL are such that the reflected light corresponding to the blue light BL mainly corresponds to the B pixels, the reflected light corresponding to the green light GL mainly corresponds to the G pixels, and the red light RL. The reflected light is mainly received by the R pixels.

In FIG. 12, the imaging sensor 56 performs an accumulation operation of accumulating signal charges in pixels and a readout operation of reading out the accumulated signal charges within an image signal acquisition period of one frame. The semiconductor light sources 35 to 37 are turned on in synchronization with the timing of the accumulation operation of the imaging sensor 56, and white light WL (BL+GL+RL) composed of mixed light of blue light BL, green light GL, and red light RL is irradiated to the observation object. , and the reflected light is incident on the imaging sensor 56 . The imaging sensor 56 color-separates the reflected light of the white light WL with each filter. The B pixels receive the reflected light corresponding to the blue light BL, the G pixels receive the reflected light corresponding to the green light GL, and the R pixels receive the reflected light corresponding to the red light RL. The imaging sensor 56 sequentially outputs image signals for one frame according to the frame rate in accordance with the readout timing.

In FIG. 13, the optical system group 41 includes collimating lenses 75, 76, and 77 for guiding each color light from each of the semiconductor light sources 35 to 37 to the incident end 61, and each color light transmitted through each of the collimating lenses 75 to 77. It is composed of dichroic mirrors 78 and 79 that combine the optical paths of light, and a condensing lens 80 that converges each color light onto the incident end 61 .

The collimating lenses 75 to 77 transmit the respective colored lights from the respective semiconductor light sources 35 to 37 and collimate the respective colored lights. 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 dichroic filters having predetermined transmission characteristics are formed on transparent glass plates. Dichroic mirrors 78 and 79 are provided between collimator lenses 75 to 77 and condenser lens 80 . Dichroic mirrors 78 and 79 constitute 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 intersect 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 a dichroic mirror 79 is provided at a position where these optical axes intersect.

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. Also, the dichroic mirror 79 is arranged in a posture inclined by 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 blue and green wavelength bands of less than about 600 nm. The dichroic mirror 78 transmits the green light GL from the green semiconductor light source 36 downstream and reflects the red light RL from the red semiconductor light source 37 . Thereby, 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 green and red wavelength bands 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 . Furthermore, the dichroic mirror 79 reflects the blue light BL from the blue semiconductor light source 35 . By the action of this dichroic mirror 79, all optical paths of blue light BL, green light GL, and red light RL are combined to generate white light WL.

Of the collimating lenses 75 to 77, the collimating lens 75 facing the blue semiconductor light source 35 and the collimating lens 77 facing the red semiconductor light source 37, excluding the collimating lens 76 facing the green semiconductor light source 36, are provided with position adjustment mechanisms (hereinafter referred to as , simply referred to as an adjustment mechanism) 81 and 82 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, thereby adjusting the blue light BL , green light GL, and red light RL. More specifically, the adjustment mechanisms 81 and 82 match the focal positions of the respective color lights by moving the collimating lenses 75 and 77 in the optical axis direction.

Like 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, a light source device having a plurality of monochromatic semiconductor light sources has a condensed light as described with reference to FIG. The focal positions BFP, GFP, and RFP of the blue light BL, green light GL, and red light RL emitted from the lens 80 may shift on the optical axis OA. The adjusting mechanisms 81 and 82 adjust the focal position BFP and the red light BL emitted from the condenser lens 80 to eliminate the color shift that changes the color of the displayed image due to the shift of each focal position. The focal position RFP of the light RL is matched with the focal position GFP of the green light GL. That is, in this embodiment, the green light GL corresponds to one color of light, and the blue light BL and red light RL correspond to the remaining colors of light.

14 and 15 showing the specific configuration of the adjustment mechanism 81, the collimating lens 75 is held by a cylindrical lens holder 90 and attached to the housing 91 of the optical system group 41. As shown in FIG. 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, respectively. The long hole 92 is formed along a direction perpendicular to the optical axis OA. The long hole 92 is formed such that its center is aligned with the optical axis OA when viewed from above and is bilaterally symmetrical with respect to the optical axis OA. The long hole 92 functions as a moving mechanism for moving the lens holder 90, that is, the collimator lens 75, in the optical axis OA direction. The guide protrusion 93 is formed over the entire width of the lens holder 90 along a direction parallel to the optical axis OA.

A fitting hole 95 into which the lens holder 90 is fitted is formed in the housing 91 . A notch 96 is provided in the upper portion of the fitting hole 95 , and a guide groove 97 is provided in the lower portion 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 . The guide groove 97 is formed across the entire width of the fitting hole 95 along the direction parallel to the optical axis OA, like the guide protrusion 93 .

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

A bearing portion 98 is provided above 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 body portion 101 having a shape that follows the upper portion of the lens holder 90 exposed by the notch 96 , and mounting portions 102 projecting from both ends of the body portion 101 . An insertion hole 104 is formed in the mounting portion 102 . A screw 105 is inserted through the insertion hole 104 . The screw 105 is screwed into a threaded hole 106 formed in the top surface of the housing 91 .

When the fixture 100 is fastened and fixed to the housing 91 with the screws 105, the main body 101 is in 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 direction of the optical axis OA 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 a fixing mechanism.

FIG. 15 shows the state of temporary fixing before fitting the lens holder 90 into the fitting hole 95 and attaching the fixture 100 to the housing 91 . In this temporarily fixed state, the eccentric driver 110 can be used to move the lens holder 90, that is, the collimator lens 75 in the optical axis OA direction.

The eccentric driver 110 is composed of a grip 111 gripped by an operator, a rotating shaft 112 projecting from the bottom of the grip 111 , and an eccentric shaft 113 projecting from the bottom of the rotating shaft 112 . The grip 111, the rotating shaft 112, and the eccentric shaft 113 are all cylindrical. The center of the grip 111 and the rotating shaft 112 are aligned. The radius of eccentric shaft 113 is half the radius of rotating shaft 112 . Also, the center of the eccentric shaft 113 is shifted from the center of the rotating shaft 112 by the radius of the eccentric shaft 113 . The rotating shaft 112 is inserted through 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 eccentric driver 110 is used to move the lens holder 90 along the optical axis OA. When the eccentric driver 110 is rotated 180° from the state shown in FIG. 16A where the eccentric shaft 113 is positioned at the center of the elongated hole 92 and the front surfaces of the lens holder 90 and the housing 91 are aligned, the state shown in FIG. , the eccentric shaft 113 rotates 180° along the elongated hole 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 indicated by the double-headed arrow, the lens holder 90 can transition between the state shown in FIG. 16(A) and the state shown in FIG. 16(B). It has an adjustment allowance for 113 diameters.

The adjusting mechanism 81 includes a guide projection 93 functioning as a guide mechanism, a guide groove 97, an elongated hole 92 functioning as a moving mechanism, and a fixture 100, a screw 105, and a screw hole 106 functioning as a fixing mechanism. Note that the adjustment mechanism 82 has the same configuration as the adjustment mechanism 81 except that the collimator lens 75 is replaced with the collimator lens 77, so illustration and description thereof will be omitted.

In FIG. 17, when the collimator lens 75 is moved in the optical axis OA direction by the adjustment mechanism 81, the focal position BFP of the blue light BL emitted from the condenser lens 80 changes. Specifically, when the collimator lens 75 moves toward the blue semiconductor light source 35 along the optical axis OA from the state shown in FIG. 17A, the light is emitted from the condenser lens 80 as shown in FIG. The focal length of the emitted blue light BL becomes longer, and the focal position BFP moves away from the condenser lens 80 . On the other hand, when the collimator lens 75 moves along the optical axis OA from the state shown in FIG. 17(A) to the side opposite to the blue semiconductor light source 35, the light is emitted from the condenser lens 80 as shown in FIG. 17(C). The focal length of the blue light BL becomes shorter, and the focal position BFP approaches the condensing lens 80 . In this embodiment, using such optical properties, the adjustment mechanism 81 moves the collimator lens 75 in the optical axis OA direction, thereby adjusting the focal position BFP of the blue light BL emitted from the condenser lens 80. . Note that the illustration of the dichroic mirror 79 is omitted in FIG. 17 to avoid complication. Also, 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, and thus the description is omitted.

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

The detection unit 120 includes a detection light guide 121 , 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 . An incident end 125 of the detection light guide 121 is provided with a connector 126 similar to the light source connector 29B of the endoscope 11 , 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 light guide 121 for detection in the optical axis OA direction at predetermined scan widths and time intervals, so that the condenser lens 80 in the light source device 13 and the incident end 125 Periodically change the positional relationship. 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 the light amount of each color light in the optical axis OA direction. Outputs a light amount waveform that indicates the amount of light.

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

The horizontal axis of the light amount waveform is assigned to the position on the optical axis OA, and the vertical axis is assigned to the light intensity. “0” on the horizontal axis indicates the center position of the scanning width of the incident end 125 by the incident end scanning device 122 . The horizontal axis indicates the position away from the condensing lens 80 toward the left minus 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. is set to -1.5 mm to 1.5 mm.

The operation of the above configuration will be described below. First, the light source device 13 is assembled such as by fitting the lens holder 90 into the fitting hole 95 . 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 match the focal positions of the blue light BL, the green light GL and the red light RL to eliminate the color shift. A final inspection including work is done before shipment.

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 predetermined scan widths and time intervals. The light amount waveform detector 123 detects the amount of light emitted from the output 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 intensity waveform displayed on the light intensity waveform monitor 124, and observes the peak of the light intensity waveform GW indicating the focal position GFP of the green light GL, the peak of the light intensity waveform BW indicating the focal position BFP of the blue light BL, The positions of the collimator lenses 75 and 77 on the optical axis OA are adjusted by the adjusting mechanisms 81 and 82 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 are aligned. 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 move the collimating lenses 75 and 77 to the optical axis. Move in the OA direction.

Here, "matching the focal position of each color light" naturally includes the case of completely matching the focal position of each color light, but also includes the case where the focal position of each color light falls within a predetermined range. This predetermined range is indicated by a line segment denoted by reference numeral 128 in FIG. The operator should ensure that the peaks of the light intensity waveforms GW, BW, and RW of the respective colored lights are at least within the predetermined range indicated by the line segment 128, and more preferably, the peaks of the light intensity waveforms GW, BW, and RW of the respective colored lights are completely adjusted. 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 so as to align the peaks of the light amount waveforms BW and RW with the peaks of the light amount waveform GW to move the collimating lenses 75 and 77 to the optical axis. By moving in the OA direction, 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 for the collimator 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 they are matched with GFP, each of the collimator lenses 75 to 77 is provided with an adjustment mechanism, 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 same adjustment mechanism as the adjustment mechanisms 81 and 82 may be provided for the collimating lens 76 as well. If the collimating lens 76 is also provided with an adjusting mechanism, the position of one of the collimating lenses 75 to 77, for example, the collimating lens 76, is first adjusted in order to eliminate the color misregistration so that the peak of the light amount waveform GW reaches the maximum. The position of the collimating lens 76 is searched for. After fixing the collimating lens 76 at the searched position, the positions of the collimating lenses 75 and 77 may be adjusted.

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

After moving the collimating lenses 75 and 77 in the direction of 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 screws the screw 105 into the screw hole 106. Together, the fixture 100 is fastened and fixed to the housing 91 to fix the positions of the collimator lenses 75 and 77 . This completes the color misregistration elimination work.

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

When endoscopic diagnosis is performed at a medical site, the endoscope 11 is connected to the processor device 12 and the light source device 13, the processor device 12 and the light source device 13 are powered on, and the endoscope system 10 is activated. .

The insertion portion 16 of the endoscope 11 is inserted into the living body to start observing the living body. The light source control unit 42 sets the drive current value to be applied to each of the LEDs 43-45, and starts lighting of each of the semiconductor light sources 35-37. Then, light amount control is performed while maintaining the target emission spectrum.

Each of the semiconductor light sources 35-37 emits blue light BL, green light GL, and red light RL from each of the LEDs 43-45. Blue light BL, green light GL, and red light RL enter collimator lenses 75 to 77 of optical system group 41, respectively.

Blue light BL is reflected by dichroic mirror 79 . Green light GL passes through dichroic mirrors 78 and 79 . Red light RL is reflected by dichroic mirror 78 and passes through dichroic mirror 79 . Dichroic mirrors 78 and 79 combine the optical paths of blue light BL, green light GL, and red light RL. These blue light BL, green light GL, and red light RL enter the condenser lens 80 . As a result, white light WL composed of mixed light of blue light BL, green light GL, and red light RL is generated. The condenser lens 80 converges 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 through the light guide 55 to the illumination window 22 and irradiated from the illumination window 22 onto the observation target. The reflected light of the white light WL reflected by the observation target enters the imaging sensor 56 through the observation window 23 . The imaging 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 section 67 . The imaging operation by the imaging sensor 56 is repeated at a predetermined frame rate. The image processing unit 67 generates a display image based on each input image signal. A 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 imaging sensor 56 .

The DSP 66 also 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 controller 42 of the light source device 13 . Based on the received exposure control signal, the light source control unit 42 determines the driving current values of the semiconductor light sources 35 to 37 so that the ratio of the amount of light of each color is constant (so that the target emission spectrum does not change). . Then, the semiconductor light sources 35 to 37 are driven with the determined drive current value. Thereby, the light amounts of the blue light BL, the green light GL, and the red light RL that constitute the white light WL by 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 elimination work is not performed and, for example, the light source device 13 is shipped with the focal positions BFP, GFP, and RFP as shown in FIG. As you can see, the color tone 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 varies due to individual differences. When the incident end 61A is at the focal position RFP of the red light RL like the light guide 55A of the endoscope 11A, a reddish display image 130R is generated as a whole. In addition, 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 whose entirety is greenish is generated, and the light of the endoscope 11C is generated. When the incident end 61C is at the focal position BFP of the blue light BL as in the guide 55C, a display image 130B that is entirely bluish is generated. Although illustration is omitted, if the positional relationship between the condensing lens 80 and the incident end 61 is different for a plurality of types of endoscopes 11D and 11E having different specifications, the endoscopes 11D and 11E The color tone of the displayed image changes.

On the other hand, in this embodiment, as shown in FIG. 20, the focal positions BFP, GFP, and RFP of the blue light BL, green light GL, and red light RL are matched by the color shift elimination work. In the endoscopes 11A to 11C, even if the positional relationship between the condensing lens 80 and the incident ends 61A, 61B, 61C changes due to individual differences, the light amount balance of each color light incident on the incident ends 61A, 61B, 61C fluctuates. As a result, the display image 130 with the same color tone is generated. Although illustration is omitted, the same is true when using a plurality of types of endoscopes 11D and 11E with different specifications. Therefore, the situation that the color tone of the displayed image changes every time the endoscopic diagnosis does not occur, and the operator can smoothly perform the endoscopic diagnosis without feeling uncomfortable.

When the semiconductor light sources 35 to 37 are used, since the semiconductor light sources 35 to 37 having rectangular light emitting portions are used, the condensed image of each color light emitted from the condensing lens 80 also becomes rectangular. In such a case, a semiconductor light source having a circular light-emitting portion is used, and the condensed image of each color of light is more likely to protrude from the incident end 61 than in the case where the condensed image of each color light 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 rectangular light emitting portions.

In the above embodiment, the collimating lenses 75 and 77 are provided with the adjusting mechanisms 81 and 82. The adjusting mechanisms are arranged in the optical paths from the semiconductor light sources 35 to 37 to the condenser lens 80 rather than the dichroic mirrors 78 and 79. It suffices if it is provided on the side of the semiconductor light sources 35 to 37 . For example, as shown in FIGS. 21 and 22, adjusting mechanisms 131 and 132 may be provided for the blue semiconductor light source 35 and the red semiconductor light source 37 in place of or in addition to the collimator 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, in addition to the collimator lenses 75 and 77, when the adjustment mechanism is provided for the blue semiconductor light source 35 and the red semiconductor light source 37, only the collimator lenses 75 and 77 or the blue semiconductor light source 35 and the red semiconductor light source in FIG. An adjustment allowance can be earned more than when only the semiconductor light source 37 is used.

However, unlike the collimator lens, the semiconductor light source is connected to wiring and other members that may hinder movement in the optical axis OA direction, so the semiconductor light source is not provided with an adjustment mechanism as in the above embodiment. Preferably, only the collimating lens is provided with an adjusting mechanism, and the collimating lens is moved in the direction of the optical axis OA to match the focal positions of the respective color lights.

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

In the above embodiment, with the focal position GFP of the green light GL as a reference, 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. or the focal position RFP of the 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 was explained that the color deviation elimination work is performed during the final inspection before shipment of the light source device 13, but the timing of performing the color deviation elimination work is not particularly limited. For example, after shipment of the light source device 13, an operator may carry the detection unit 120 and go to the customer's site to perform the color misregistration work according to the customer's request.

The adjustment mechanism is not limited to the configuration illustrated in the above embodiment. For example, the guide mechanism can be composed of the lens holder 90 and the fitting hole 95 itself without providing the guide projections 93 and the guide grooves 97 of the above embodiment. Further, as the moving mechanism, instead of the elongated hole 92 of the above embodiment, a well-known moving mechanism such as a ball screw, a push-pull bolt, an eccentric cam, etc., which converts rotary motion into rectilinear motion may be used. Furthermore, the fixing mechanism may also be composed of a pair of C-rings that sandwich the lens holder 90 from both sides and screws that fasten and fix the pair of C-rings. In short, any mechanism can be used as long as it can guide the movement of the optical member such as the collimator lens 75 in the direction of the optical axis OA, move the optical member in the direction of the optical axis, 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. (violet light VL) may be added.

In FIG. 23, the violet semiconductor light source 135 has, as a light emitting element, a violet LED (not shown) that emits violet light VL. A specific structure of the violet semiconductor light source 135 is the same as that of the blue semiconductor light source 35 shown in FIGS. As shown in FIG. 24, the violet semiconductor light source 135 emits violet light VL having a wavelength component in the vicinity of 380 nm to 420 nm, which is a wavelength band of violet, and 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 the violet light VL and converts the violet light VL into substantially parallel light, and a dichroic mirror 138 that combines the optical paths of the blue light BL and the violet light VL. This is an added configuration. The blue semiconductor light source 35 and the violet 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. 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 violet semiconductor light source 135 .

The dichroic filter of the dichroic mirror 138 has the property of reflecting light in the violet wavelength band, eg, less than about 430 nm, and transmitting light in the blue, green, and red wavelength bands above that. The dichroic mirror 138 transmits the blue light BL from the blue semiconductor light source 35 downstream and reflects the violet light VL from the violet semiconductor light source 135 . Thereby, the optical paths of the blue light BL and the violet light VL are combined. The violet light VL reflected by the dichroic mirror 138 is reflected by the dichroic mirror 79 toward the condenser lens 80 because the dichroic mirror 79 has the characteristic of reflecting light in the blue wavelength band of less than about 480 nm as described above. . Thereby, the optical paths of all the blue light BL, green light GL, red light RL, and violet light VL are combined.

The collimating lens 137 is provided with an adjusting mechanism 139, like the collimating lenses 75 and 77 of the above embodiments. The adjustment mechanism 139 moves the collimating lens 137 in the direction of the optical axis OA to match the focal position of the violet 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 sharply in the wavelength band below 450 nm, and drops most around 405 nm. When an object to be observed is irradiated with light in a wavelength band with a low reflectance, a display image with a difference in contrast between the blood vessel and other parts is obtained because the blood vessel absorbs the light significantly.

Moreover, the light scattering properties of living tissue also have 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 greater the scattering, the more light is reflected near the surface layer of the mucous membrane of the living tissue, and the less light reaches the middle and deep layers. Therefore, the shorter the wavelength, the lower the penetration depth, and the longer the wavelength, the higher the penetration depth.

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

When emphasizing superficial blood vessels, 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 imaging sensor 56 . When the semiconductor light sources 35 to 37 and 135 are turned on, violet light VL is added to the white light WL of the above embodiment, and the mixed light (WL+VL) is irradiated as illumination light to the observation object.

The illumination light obtained by adding the violet light VL to the white light WL is separated by the micro color filters of the imaging sensor 56 . The B pixels receive the reflected light corresponding to the violet light VL in addition to the reflected light corresponding to the blue light BL. The G pixel and the R pixel receive reflected light corresponding to the green light GL and reflected light corresponding to the red light RL, respectively, as in the above embodiment. The imaging sensor 56 sequentially outputs the B, G, and R image signals according to the frame rate in accordance with the readout timing.

In this case, the B image signal includes a reflected light component corresponding to the violet light VL in addition to the reflected light component corresponding to the blue light BL constituting the white light WL. rendered in contrast. In lesions such as cancer, the density of surface blood vessels tends to be higher than in normal tissue, and the pattern of surface blood vessels is characteristic. This is preferable because it makes it easier to identify lesions.

In the above embodiment, the light amount of each color light is controlled by changing the driving current value applied to each LED 43 to 45 based on the exposure control signal from the processor device 12. , the semiconductor light source may fluctuate in output light intensity with respect to the driving current value. Therefore, a light amount measuring sensor for measuring the light amount of each color light is provided in the optical system group, and whether or not the light amount of each color light has reached the target value is monitored based on the light amount measurement signal output by the light amount measuring sensor. may

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

In the above embodiments, semiconductor light sources composed only of LEDs are mentioned. It is also possible to use a fluorescent semiconductor light source composed of a green phosphor that emits green light in a green wavelength band. Further, instead of or in addition to the green semiconductor light source, the red semiconductor light source is a blue excitation light LED that emits blue excitation light in a wavelength band from violet to blue, and a red fluorescence LED that is excited by the blue excitation light and has a red wavelength band. may be composed of a red phosphor that emits 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 a wavelength band from violet to blue, but a green excitation light emitting element that emits green excitation light in a green wavelength band. It may be an excitation light emitting device. In this case, instead of the resin 78, the cavity 76 shown in FIGS. 5 and 6 is filled with a phosphor to form a fluorescent semiconductor light source.

Moreover, 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 having microlenses instead of a surface mount type. Further, 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 provided integrally, but 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 from the excitation light LED is guided to the phosphor via the light guide member.

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

The configuration of the optical system group in the above embodiment is an example, and various modifications are possible. For example, a dichroic mirror in which a dichroic filter is formed on a transparent glass plate is used as an optical member constituting the third optical system, but a dichroic prism in which a dichroic filter is formed on a prism may be used instead. Also, instead of optical members forming dichroic filters such as dichroic mirrors and dichroic prisms, 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 A bifurcated light guide may be used to combine the optical paths. A branch type light guide is obtained by dividing a predetermined number of optical fibers at one end into a plurality of fibers and branching the incident end into a plurality of branches. In this case, each semiconductor light source is arranged so as to correspond to each branched incident end.

In the above embodiments, 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 was exemplified. The present invention can also be applied to a light source device having two monochromatic semiconductor light sources. A mixed light of blue light BL and green light GL or a mixed light of green light GL and violet light VL may be irradiated to the observation target to obtain a display image based on green light GL.

In the above embodiment, the image sensor 56 is an example of a color image sensor that separates illumination light by B, G, and R micro color filters, and the color image sensor acquires B, G, and R image signals at the same time. A simultaneous type endoscope system and a light source device used therein have been described as an example. The present invention may also be applied to a frame sequential endoscope system that acquires .

In the above embodiment, an example in which the light source device and the processor device are configured separately has been described, but these devices may be configured integrally. In addition, the present invention provides an endoscope system using a fiber scope that guides the reflected light of an observation target of illumination light with an image guide, and an ultrasonic endoscope that has an imaging sensor and an ultrasonic transducer built in the tip. and the light source device used therein.

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 collimating lens ( first optical system, optical member)
78, 79, 138 dichroic mirror (third optical system)
80 condenser lens (second optical system)
81, 82, 139 adjustment mechanism 92 long hole 93 guide projection 97 guide groove 100 fixture 105 screw 106 screw hole 110 eccentric driver 120 detection unit 135 violet semiconductor light source BL blue light GL green light RL red light WL white light VL violet light BFP Blue light focal position GFP Green light focal position RFP Red light focal position BW Blue light intensity waveform GW Green light intensity waveform RW Red light intensity waveform

Claims (5)

An endoscope light source device for supplying illumination light to a light guide of an endoscope, comprising a plurality of monochromatic semiconductor light sources each emitting light of a plurality of colors as the illumination light, and at least one optical member, a plurality of first optical systems that respectively transmit the plurality of colors of light from the semiconductor light source; and a second optical system that converges the plurality of colors of light transmitted through the plurality of first optical systems onto an incident end of the light guide. system and a position adjusting mechanism for adjusting the position of the optical member in the optical axis direction of the first optical system , and connectable to a detection unit including a light guide for detection ,
When the position of the incident end of the light guide for detection is moved in the optical axis direction using a guide mechanism and a moving mechanism, the position of each color light through the light guide for detection is changed with respect to the position of the incident end. 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 respective colored lights shown match ;
and a fixing step of fixing the position of the optical member in the lens holder by pressing the lens holder with a fixing mechanism. 2. The position adjusting method according to claim 1, wherein the moving mechanism moves the lens holder in the optical axis direction by converting rotational motion into linear motion. The lens holder is provided with an elongated hole,
In the moving step, the eccentric shaft of the eccentric driver is fitted into the elongated hole, and the rotational motion is imparted to the eccentric driver to rotate the eccentric shaft along the elongated hole, thereby moving the lens holder. 3. The position adjustment method according to claim 2, wherein the linear movement is performed in the direction of the optical axis. In the fixing step, a fixture is used to fix the position of the optical member;
4. The position adjusting method according to claim 3, wherein the fixture presses the upper part of the lens holder . 5. The position adjusting method according to claim 1, wherein, in said fixing step, said fixing mechanism presses said lens holder from a direction intersecting said optical axis direction.

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