JP2020114408A - Light source device for endoscope and endoscope system - Google Patents

Abstract

To provide a light source device for an endoscope capable of reducing a change in a hue of a display image each time endoscopic diagnosis is carried out when using a plurality of monochrome semiconductor light sources which emit lights of a plurality of colors respectively, and an endoscope system.SOLUTION: A collimator lens 75 for transmitting a blue light BL from a blue semiconductor light source 35 and a collimator lens 77 for transmitting a red light RL from a red semiconductor light source 37 are provided with adjusting mechanisms 81 and 82 respectively. The adjusting mechanisms 81 and 82 cause a focal position BFP of the blue light BL and a focal position RFP of the red light RL to coincide with a focal position GFP of a green light GL by moving the collimator lenses 75 and 77 in an optical axis OA direction. The adjusting mechanisms 81 and 82 include a guide mechanism for guiding the movement of the collimator lenses 75 and 77 in the optical axis OA direction, and a moving mechanism for moving the collimator lenses 75 and 77 in the optical axis OA direction.SELECTED DRAWING: Figure 13

Description

The present invention relates to an endoscope light source device and an endoscope system for supplying illumination light to an endoscope.

In medical practice, endoscopic diagnosis using an endoscope system is actively performed. The endoscope system includes an endoscope, a processor device that processes an image signal output from the endoscope, a light source device for an endoscope that supplies illumination light to the endoscope (hereinafter, simply referred to as a light source device). Equipped with.

The endoscope has an insertion part to be inserted into a living body, and an illumination window for irradiating the observation target with illumination light and an observation window for imaging the observation target are arranged at the tip of the insertion part. There is. The endoscope has a built-in light guide made 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. An incident end of the light guide on which the illumination light is incident is arranged in the light source device, and an emission end of the light guide on which the illumination light is emitted is arranged at 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 sensor images the observation target illuminated with the 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 cleaned and disinfected. Then, when the next endoscopic diagnosis is started, it is connected to the processor device and the light source device again. In the medical field, multiple endoscopes of the same model or multiple types of endoscopes with specifications according to the contents of endoscopic diagnosis are prepared, and the processor device and the light source device are of the same model. It is possible to replaceably connect a plurality of endoscopes and a plurality of types of endoscopes having different specifications.

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, in place of these, a laser diode (LD: Laser Diode) or a light emitting diode (LED: Light Emitting Diode) is used. There has been proposed a light source device using a semiconductor light source having a light emitting element such as (see Patent Document 1).

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

Japanese Unexamined Patent Publication No. 2015-047402

In the 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 closer to the incident end of the light guide. To be precise, it is ideal to have a structure in which the light guide constitutes the focal point at the incident end of the fiber bundle.

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

Factors that cause the respective focal positions to shift include assembling errors and individual differences in each part of the configuration that supplies illumination light such as blue, green, and red semiconductor light sources and the first to third optical systems. For example, if 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 focus position BFP of the blue light BL is also displaced. Alternatively, if the wavelength range or center wavelength of the red light RL is shifted due to individual differences of the red semiconductor light sources, the refractive index of the red light RL in the first optical system and the third optical system changes, so the focus position of the red light RL is changed. It slips.

When each focus position shifts, a light amount waveform BW (indicated by a broken line), GW (indicated by a thick solid line), and RW (indicated by a thin solid line) representing the amount of light on the optical axis OA of the three color lights BL, GL, and RL in FIG. As shown by (), the peaks of the light amounts of the three-color lights BL, GL, and RL corresponding to the respective focal positions are also displaced on the optical axis OA. The light quantity waveform is a peak-shaped waveform at the focus position, and is a mountain-shaped waveform that falls symmetrically before and after the focus position. The light intensity waveforms BW, GW, and RW have substantially the same shape.

If the peaks of the respective light amount waveforms BW, GW, and RW deviate, the light amount balance of the three color lights BL, GL, and RL changes depending on the distance from the second optical system 200. For example, at the focus position RFP of the red light RL, the light amount of the red light RL is the highest, and then the light amounts of the green light GL and the blue light BL are lower. On the contrary, at the focus position BFP of the blue light BL, the light quantity of the blue light BL is the highest, and then the light quantities of the green light GL and the red light RL decrease in this order.

In such a case, the light amount balance of the lights BL, GL, and RL of the three colors 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 display image A color shift that changes the tint occurs. For example, when the incident end 202B is at the focus position GFP of the green light GL as in the light guide 201B, the illumination light is greenish because the light amount of the green light GL is the highest, and the entire display is greenish. The image 203G is generated. When the incident end 202A is at the focus position RFP of the red light RL as in the light guide 201A, a display image 203R that is entirely reddish is generated, and the incident end 202C is blue as in the light guide 201C. When it is at the focus position BFP of the light BL, a display image 203B that is entirely bluish is generated.

As described above, the endoscope is detached from the light source device or connected to the light source device each time the endoscope diagnosis is performed. Further, when a plurality of endoscopes of the same model are shared by one light source device, the second optical system 200 and the entrance end 202 may be different due to individual differences of the endoscopes even though they are of the same model. The positional relationship with and will change. Further, 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 entrance end 202. Exists. Therefore, the positional relationship between the second optical system 200 and the entrance end 202 is not always the same, and differs depending on the connection with the light source device, individual differences in endoscopes, and specifications. Therefore, in the case where the focal positions of the light of a plurality of colors are deviated, the tint of the displayed image may change each time endoscopic diagnosis is performed.

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

The present invention, when using a plurality of monochromatic semiconductor light sources that respectively emit light of a plurality of colors, an endoscope light source device capable of reducing a change in tint of a display image at each time of endoscopic diagnosis, An object is to provide an endoscope system.

In order to achieve the above object, the present invention provides a light source device for an endoscope that supplies illumination light to a light guide of an endoscope, and a plurality of monochromatic semiconductor light sources that respectively emit light of a plurality of colors as illumination light, and at least A plurality of first optical systems configured of a single optical member and transmitting a plurality of colors of light from a plurality of monochromatic semiconductor light sources, respectively, and a plurality of colors of light transmitted through the plurality of first optical systems are incident on a light guide. A second optical system for converging light on the end and a position adjusting mechanism for adjusting the position of the optical member in the optical axis direction of the first optical system, which can be connected to a detection unit including a detection light guide, and position adjustment The mechanism adjusts the position of the optical member so as to match the peaks of the light amount waveforms of the respective colored lights indicating the focal position of the respective colored lights, and the position adjusting mechanism is a guide mechanism for guiding the movement of the optical member in the optical axis direction, And a moving mechanism for moving the optical member in the optical axis direction.

It is preferable that the position adjustment mechanisms are provided in the same number as the number of lights of the remaining colors other than the light of one color among the lights of the plurality of colors. It is preferable to include a third optical system that is provided between the plurality of first optical systems and the second optical system and that couples the optical paths of the lights of the plurality of colors that have passed through the plurality of first optical systems. It is preferable that the position adjusting mechanism is provided closer to the monochromatic semiconductor light source side than the third optical system in the optical path from the monochromatic semiconductor light source to the second optical system. It is preferable that each of the plurality of monochromatic semiconductor light sources has a rectangular light emitting portion.

It is preferable that the plurality of monochromatic semiconductor light sources are a blue semiconductor light source, a green semiconductor light source, and a red semiconductor light source that respectively emit light of three colors of blue light, green light, and red light as illumination light. The blue semiconductor light source emits blue light having a center wavelength of 460±10 nm and a half value width of 25±10 nm, the green semiconductor light source emits green light having a center wavelength of 550±10 nm and a half value width of 100±10 nm, and the red semiconductor light source has a center wavelength. It is preferable to emit red light having a wavelength of 625±10 nm and a half width of 20±10 nm.

The position adjusting mechanism preferably adjusts the position of the monochromatic semiconductor light source in the optical axis direction in addition to the optical member. The moving mechanism has a housing in which a lens holder for holding the optical member is provided, and the moving mechanism uses the elongated hole provided in the lens holder to move the optical member in the lens holder in the optical axis direction. The guide protrusion provided on the lens holder and the guide groove formed on the housing guide the movement of the optical member in the lens holder in the optical axis direction, and the fixing mechanism fits the lens holder into the fitting hole in the housing. It is preferable that the position of the optical member in the lens holder is fixed by pressing the lens holder with the fixing portion in the retracted state.

The position adjustment mechanism matches the peak of the light quantity waveform of the green light indicating the focus position of the green light with the peak of the light quantity waveform indicating the focus position of the blue light and the peak of the light quantity waveform indicating the focus position of the red light. It is preferable to adjust the position of the optical member.

The present invention includes an endoscope having a light guide that guides illumination light, and an endoscope light source device that supplies illumination light to the light guide. In an endoscope system shared by a light source device for an endoscope, the light source device for 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 for respectively transmitting the light of a plurality of colors from the light source, and a second optical system for condensing the light of a plurality of colors transmitted through the plurality of first optical systems at the incident end of the light guide; A position adjusting mechanism that adjusts the position of the member in the optical axis direction of the first optical system, and is connectable to a detection unit that includes a detection light guide. The position adjusting mechanism is for each color indicating the focal position of each color light. The position adjustment mechanism adjusts the position of the optical member so that the peaks of the light quantity waveforms of the light coincide with each other. Have and.

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

It is an external view of an endoscope system. It is a front view of the front-end|tip part of an endoscope. It is an explanatory view of an 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 a blue semiconductor light source. It is a top view which shows a blue semiconductor light source. It is a graph which shows the emission spectrum of the blue light which a blue semiconductor light source emits. It is a graph which shows the emission spectrum of the green light which a green semiconductor light source emits. It is a graph which shows the emission spectrum of the red light which a red semiconductor light source emits. It is a graph which shows the emission spectrum of white light comprised by blue light, green light, and red light. It is a graph which shows the spectral characteristic of the micro color filter of an image sensor. It is explanatory drawing which shows the irradiation timing of white light and the operation timing of an imaging sensor. It is a figure which shows arrangement|positioning 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. It is a perspective view of a lens holder, a housing, and an eccentric driver. It is explanatory drawing which shows a mode that the lens holder is moved to an optical axis direction using an eccentric driver in the state which temporarily fixed the lens holder to the housing. It is explanatory drawing which shows the change of the focus position by the movement of the collimating lens to 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 a display image, when each focus position of blue light, green light, and red light has shifted. It is explanatory drawing which shows the relationship of the position of the incident end of a light guide, and a display image, when each focus position of blue light, green light, and red light corresponds. It is a figure which shows arrangement|positioning of each semiconductor light source in the case of providing a blue semiconductor light source, and a red semiconductor light source with an adjustment mechanism instead of a collimator lens, and a detailed structure of an optical system group. It is a figure which shows arrangement|positioning of each semiconductor light source at the time of providing an adjustment mechanism in a blue semiconductor light source, and a red semiconductor light source in addition to a collimating lens, and a detailed structure of an optical system group. It is a figure which shows arrangement|positioning of each semiconductor light source when adding a purple semiconductor light source, and the detailed structure of an optical system group. It is a graph which shows the emission spectrum of the purple light which a purple semiconductor light source emits. FIG. 10 is an explanatory diagram showing the relationship between the position of the incident end of the light guide and the display image when the focus positions of blue light, green light, and red light are deviated in the conventional light source device.

1, an endoscope system 10 includes an endoscope 11 that images 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. The light source device 13 that supplies the endoscope 11 with illumination light that illuminates the endoscope 11. A monitor 14 that displays 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 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, a universal cord that connects the endoscope 11, the processor device 12, and the light source device 13. 18 and.

The insertion portion 16 is composed of a distal end portion 19, a bending portion 20, and a flexible tube portion 21, which are sequentially provided from the distal end. As shown in FIG. 2, 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 for cleaning the observation target 23 are provided on the front end surface of the distal end portion 19. An air/water supply nozzle 24 for supplying air/water and a forceps outlet 25 for projecting a treatment tool such as forceps or an electric knife to perform various treatments are provided. An imaging sensor 56 and an objective optical system 63 for image formation (both of which are shown in FIG. 4) are built in the observation window 23.

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

In addition to the amble knob 26, the operation section 17 includes a forceps port 27 for inserting a treatment tool, an air/water feed button 28 operated when air/water is fed from the air/water feed nozzle 24, and a still image. A release button (not shown) for photographing is 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 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. The communication connector 29A is provided with one end of a communication cable, and the light source connector 29B is provided with an incident end 61 (see FIG. 4) of the light guide 55.

When the endoscope diagnosis is completed, the connection of the connector 29 is released, and the endoscope 11 is removed from the processor device 12 and the light source device 13 and washed/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 A plurality of types (indicated by reference numerals 11D and 11E) having different specifications are prepared according to the contents of the 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 endoscopes 11D and 11E of 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 that emits three lights of blue, green, and red, 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, as a light emitting element, has 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, each of the LEDs 43 to 45 is formed by joining a P-type semiconductor and an N-type semiconductor. Then, when a voltage is applied, electrons and holes recombine in the vicinity of the PN junction beyond the band gap and a current flows, and at the time of recombination, energy corresponding to the band gap is emitted as light. The amount of light emitted from each of the LEDs 43 to 45 increases or decreases according to the increase or decrease in the supplied power.

Drivers 50, 51, and 52 are connected to the LEDs 43 to 45, respectively. The light source control unit 42 controls the lighting and extinguishing of the LEDs 43 to 45 and the control of the light amount via the drivers 50 to 52. The light amount 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.

Under the control of the light source control unit 42, the drivers 50 to 52 continuously apply a drive current to the LEDs 43 to 45 to turn on the LEDs 43 to 45. Then, by changing the value of the drive current to be applied according to the exposure control signal, the power supplied to each of the LEDs 43 to 45 is changed, and the light amount of each color light of the blue light BL, the green light GL, and the red light RL is controlled respectively. To do. It should be noted that PAM (Pulse Amplitude Modulation) control that changes the amplitude of the drive current pulse by applying the drive current in pulses instead of continuously and PWM (Pulse Width Modulation) control that changes the duty ratio of the drive current pulse. You may go.

The optical system group 41 combines the optical paths of the respective color lights of the blue light BL, the green light GL, and the red light RL into one optical path, and focuses the respective color lights on the incident end 61 of the light guide 55 of the endoscope 11. Although illustration is omitted, 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 regulation member that regulates the insertion amount of the light source connector 29B into the receptacle connector 54 is provided. Further, a protective glass is provided on each of the light source connector 29B and the receptacle connector 54.

The endoscope 11 includes a light guide 55, an imaging sensor 56, an analog processing circuit 57 (AFE: Analog Front End), and an imaging control unit 58. The light guide 55 includes 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 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 end portion 19 is branched into two in front of the illumination window 22 so that 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 a concave lens and widens the divergence angle of the light emitted from the light guide 55. Thereby, the illumination light can be applied to a wide range of the observation target.

An objective optical system 63 and an image sensor 56 are arranged behind the observation window 23. The image of the observation target enters 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 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 forming pixels such as photodiodes are arranged in a matrix on an image pickup surface 56A thereof. There is. The image sensor 56 photoelectrically converts the light received by the image pickup surface 56A, and accumulates signal charges corresponding to the amount of light received in each pixel. The signal charges are converted into voltage signals by the amplifier and read out. The voltage signal is output as an image signal from the image sensor 56 to the AFE 57.

The AFE 57 includes a correlated double sampling circuit, an automatic gain control circuit, and an analog/digital converter (all of which are not shown). The correlated double sampling circuit performs correlated double sampling processing on the analog image signal from the image sensor 56, and removes noise due to resetting of 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 according 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 a drive signal to the imaging sensor 56 in synchronization with a reference clock signal input from the controller 65. The image 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 sensor 56 is a color image sensor, and a micro color filter of three colors of a blue micro color filter (B filter), a green micro color filter (G filter), and a red micro color filter (R filter) is provided on the imaging surface 56A. And each filter is assigned to each pixel. The array of each filter is, for example, a Bayer array.

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

The processor device 12 includes a controller 65, 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) that stores a control program and setting data necessary for control, a RAM (Random Access Memory) that loads a program, and functions as a working memory. , CPU controls the respective units of the processor device 12 by executing the control program.

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

Further, the DSP 66 calculates an exposure value based on each image signal and increases the light amount of the illumination light when the light amount of the entire image is insufficient (underexposure), while the light amount is too high. For (overexposure), an exposure control signal for controlling the light amount of the illumination light is output to the controller 65. The controller 65 sends an exposure control signal to the light source controller 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 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 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 via the display control unit 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 housing the blue LED 43, and a cavity 76. And a resin 78 encapsulated in. The blue LED 43 is connected to the substrate 75 by the 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 its width becomes narrower toward the substrate 75 side. The 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 the blue light BL. The size of the opening of the cavity 76 is, 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 the semiconductor light sources 35 to 37 have basically the same structure, 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 a wavelength component in the vicinity of 420 nm to 500 nm, which is a blue wavelength band, for example, and emits blue light BL having a central 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 a wavelength component in the vicinity of 480 nm to 600 nm, which is a green wavelength band, and emits a green light GL having a central wavelength of 550±10 nm and a half width of 100±10 nm. To do. Further, as shown in FIG. 9, the red semiconductor light source 37 has a wavelength component in the vicinity of 600 nm to 650 nm, which is a red wavelength band, and emits red light RL having a central wavelength of 625±10 nm and a half width of 20±10 nm. .. The center wavelength indicates the wavelength at the center of the emission spectrum of each color light, and the half-value width is the range of wavelengths that shows half the peak of the emission spectrum of each color light.

FIG. 10 shows an emission spectrum of a 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 the color rendering properties of the white light WL equivalent to that of the white light emitted from the xenon light source, the emission spectrum of the white light WL does not include a wavelength band having no light intensity component.

FIG. 11 is a graph showing the spectral characteristics of the B filter, G filter, and R filter provided on the imaging surface 56A of the imaging sensor 56. The B pixel to which the B filter is assigned is sensitive to light in the wavelength band of approximately 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 approximately 450 nm to 630 nm. The R pixel to which the R filter is assigned is sensitive to light in the wavelength band of approximately 580 nm to 800 nm. Of the blue light BL, the green light GL, and the red light RL that form the white light WL, the reflected light corresponding to the blue light BL mainly corresponds to the B pixel, and the reflected light corresponding to the green light GL mainly corresponds to the G pixel and the red light RL. The reflected light is mainly received by each R pixel.

In FIG. 12, the image sensor 56 performs an accumulation operation of accumulating the signal charges in the pixels and a reading operation of reading out the accumulated signal charges within the acquisition period of the image signal of one frame. The semiconductor light sources 35 to 37 are turned on at the timing of the accumulation operation of the image sensor 56, and white light WL (BL+GL+RL), which is 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 sensor 56. The image sensor 56 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 sensor 56 sequentially outputs an image signal for one frame in accordance with the frame rate in accordance with the read timing.

In FIG. 13, the optical system group 41 includes collimator lenses 75, 76 and 77 for guiding the respective color lights from the respective semiconductor light sources 35 to 37 to the incident end 61, and respective colors transmitted through the collimator lenses 75 to 77. It is composed of dichroic mirrors 78 and 79 for coupling the optical paths of light and a condenser lens 80 for condensing each color light at an incident end 61.

The collimator lenses 75 to 77 transmit the respective color lights from the respective semiconductor light sources 35 to 37 and convert the respective color lights into substantially parallel lights. The collimator lenses 75 to 77 form a plurality of first optical systems and also correspond to optical members that form the first optical system. The dichroic mirrors 78 and 79 are optical members formed by forming a dichroic filter having a predetermined transmission characteristic on a transparent glass plate. The dichroic mirrors 78 and 79 are provided between the collimator 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 matches 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 a dichroic mirror 79 is provided at a position where these optical axes are orthogonal.

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. Further, 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.

The dichroic filter of the dichroic mirror 78 has a characteristic of reflecting light in the red wavelength band of about 600 nm or more and transmitting light in the blue and green wavelength bands of less than about 600 nm, for example. 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. 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 the blue wavelength band of less than about 480 nm and transmitting light in the green and red wavelength bands of about 480 nm or more. Therefore, the dichroic mirror 79 transmits the green light GL that has passed through the dichroic mirror 78 and the red light RL that has been 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, and the white light WL is generated.

Of the collimator lenses 75 to 77, the collimator lens 75 facing the blue semiconductor light source 35 except for the collimator lens 76 facing the green semiconductor light source 36, and the collimator lens 77 facing the red semiconductor light source 37 include a position adjusting mechanism (hereinafter referred to as a position adjusting mechanism). 81, 82 are provided. The adjustment mechanisms 81 and 82 adjust the positions of the collimator 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 the blue light BL. , The green light GL and the red light RL are the mechanisms for matching the focal positions of the respective colored lights. More specifically, the adjustment mechanisms 81 and 82 move the collimator lenses 75 and 77 in the optical axis direction to match the focal positions of the respective color lights.

In the 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 focus 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 shift on the optical axis OA. The adjustment mechanisms 81 and 82 eliminate the color shift in which the tint of the display image changes due to the shift in the focus positions, so that the focus position BFP of the blue light BL emitted from the condenser lens 80 and the red color. The focus position RFP of the light RL is matched with the focus position GFP of the green light GL. That is, in the present embodiment, the green light GL corresponds to one color of light, and the blue light BL and the red light RL correspond to the remaining colors of light.

14 and 15 showing the specific configuration of the adjusting mechanism 81, the collimator lens 75 is held by a cylindrical lens holder 90 and attached to the housing 91 of the optical system group 41. An elongated hole 92 is provided on the upper portion of the lens holder 90, and a guide protrusion 93 is provided on the lower portion facing the elongated hole 92. The long 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 long hole 92 functions as a moving mechanism that moves 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 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. The guide groove 97 is formed over 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 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 collimator 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 above the cutout 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 the lens holder 90 is fitted into the fitting hole 95, the fixture 100 is attached to the housing 91. The fixture 100 includes a main body 101 having a shape that follows the upper portion of the lens holder 90 exposed by the notches 96, and mounting portions 102 that project from both ends of the main body 101. An insertion hole 104 is formed in the mounting portion 102. The screw 105 is inserted into the insertion hole 104. The screw 105 is screwed into a 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 the screw 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 the upper portion. As a result, 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 collimator lens 75 is fixed. The fixture 100, the screw 105, and the screw hole 106 function as a fixing mechanism.

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 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 includes a grip 111 that an operator grips, a rotating shaft 112 that projects from a lower portion of the grip 111, and an eccentric shaft 113 that projects from a lower portion of the rotating 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 rotating shaft 112 coincide. The radius of the eccentric shaft 113 is 1/2 of the radius of the rotating shaft 112. The center of the eccentric shaft 113 is displaced from the center of the rotating shaft 112 by the radius of the eccentric shaft 113. The rotary 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 eccentric driver 110 is used to move the lens holder 90 in the optical axis OA direction. When the eccentric driver 110 is rotated 180° from the state shown in FIG. 16A in which the eccentric shaft 113 is located at the center of the elongated hole 92 and the front surfaces 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 elongated hole 92. With the rotation of the eccentric shaft 113, the lens holder 90 projects 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 is capable of transitioning 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 includes 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 fixture 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 is replaced with the collimator lens 75 from the collimator lens 77, and therefore the illustration and description thereof are omitted.

In FIG. 17, when the adjusting mechanism 81 moves the collimator lens 75 in the optical axis OA direction, the focus position BFP of the blue light BL emitted from the condenser lens 80 changes. Specifically, when the collimator lens 75 moves to the blue semiconductor light source 35 side 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. 17B. The focal length of the blue light BL is increased, and the focal position BFP moves away from the condenser lens 80. Conversely, when the collimator lens 75 moves from the state shown in FIG. 17A to the side opposite to the blue semiconductor light source 35 along the optical axis OA, it is emitted from the condenser lens 80 as shown in FIG. 17C. The focal length of the blue light BL which becomes short becomes shorter, and the focal position BFP approaches the condenser lens 80. In the present embodiment, by utilizing such optical properties, the adjusting mechanism 81 moves the collimator lens 75 in the optical axis OA direction, thereby adjusting the focus position BFP of the blue light BL emitted from the condenser lens 80. .. Note that the dichroic mirror 79 is not shown in FIG. 17 to avoid complication. Further, the change of the focal position RFP of the red light RL by the adjusting mechanism 82 is the same as in the case of FIG.

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

The detection unit 120 includes a detection light guide 121, an incident end scanning device 122, a light quantity waveform detection device 123, and a light quantity 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 the condensing lens 80 in the light source device 13 and the incident end 125 are separated from each other. 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 the plurality of endoscopes 11A to 11C of the same model is set.

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

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

The horizontal axis of the light quantity 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 scan width of the incident end 125 by the incident end scanning device 122. The horizontal axis indicates the position of moving away from the condenser lens 80 as it moves toward the negative 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 the 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. Shows the case where the scan width of is set to -1.5 mm to 1.5 mm.

The operation of the above configuration will be described below. First, assembling work of the light source device 13, such as fitting the lens holder 90 into the fitting hole 95, is performed. After the assembling 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 in which the focal positions of the blue light BL, the green light GL, and the red light RL are matched. Final inspection before shipping including work is performed.

In the color misregistration 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 quantity waveform detection device 123, and the light quantity waveform monitor 124 of the detection unit 120 are driven. As a result, the incident end 125 of the detection light guide 121 is reciprocally moved in the optical axis OA direction by the incident end scanning device 122 with a predetermined scan width and time interval. Further, the light quantity waveform detection device 123 detects the light quantity of the light emitted from the emitting end of the detection light guide 121 at a predetermined timing, and the light quantity waveform as the detection result is displayed on the light quantity waveform monitor 124.

The operator observes the light quantity waveform displayed on the light quantity waveform monitor 124, and at the peak of the light quantity waveform GW indicating the focus position GFP of the green light GL, the peak of the light quantity waveform BW indicating the focus position BFP of the blue light BL, And the positions of the collimating 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 focus position RFP of 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 move the collimator lenses 75 and 77 to the optical axes. Move in OA direction.

Here, "to match the focal positions of the respective colored lights" naturally includes 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 displayed by the line segment indicated by reference numeral 128 in FIG. The operator preferably sets the peaks of the light intensity waveforms GW, BW, RW of each color light to be at least within the predetermined range indicated by the line segment 128, more preferably the peaks of the light intensity waveforms GW, BW, RW of each color light completely. 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 moved to the optical axes. It is only necessary to move 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 adjusting mechanisms 81 and 82 are provided only on the collimating lenses 75 and 77, and the focus position BFP of the blue light BL and the focus position RFP of the red light RL are set to the focus position of the green light GL with reference to the focus position GFP of the green light GL. Since the GFP and the GFP are matched with each other, the adjusting mechanism can be provided in each of the collimating lenses 75 to 77, and the labor of the adjustment can be saved as compared with the case of adjusting the focus positions of the lights of the three colors.

Of course, the collimating lens 76 may be provided with the same adjusting mechanism as the adjusting mechanisms 81 and 82. When 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 the color misregistration elimination work so that the peak of the light quantity waveform GW is the maximum. The position of the collimating lens 76 is searched for. Then, after fixing the collimator lens 76 to the searched position, the positions of the collimator lenses 75 and 77 may be adjusted.

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

After moving the collimator lenses 75 and 77 in the optical axis OA direction 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. Then, the fixture 100 is fastened and fixed to the housing 91, and the positions of the collimator lenses 75 and 77 are fixed. This completes the color misregistration elimination work.

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

When performing an endoscopic diagnosis in a medical field, 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 turned on, and the endoscope system 10 is activated. ..

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

The semiconductor light sources 35 to 37 emit blue light BL, green light GL, and red light RL from the LEDs 43 to 45, respectively. The blue light BL, the green light GL, and the red light RL enter the collimator 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 transmitted through the dichroic mirror 79. The dichroic mirrors 78 and 79 combine the optical paths of the blue light BL, the green light GL, and the red light RL. The blue light BL, the green light GL, and the red light RL enter the condenser lens 80. As a result, the white light WL including the mixed light of the blue light BL, the green light GL, and the red light RL is generated. The condenser lens 80 condenses 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 through the illumination window 22. The reflected light of the white light WL reflected by the observation target enters the image sensor 56 through the observation window 23. The image sensor 56 outputs the B image signal, the G image signal, and the 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 via the display control unit 69. The display image is updated according to the frame rate of the image sensor 56.

Further, the DSP 66 calculates an exposure value based on each image signal, and transmits an exposure control signal according 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 value of each semiconductor light source 35 to 37 based on the received exposure control signal so that the ratio of the light amount of each color light becomes constant (the target emission spectrum does not change). .. Then, the semiconductor light sources 35 to 37 are driven by the determined drive current value. As a result, the light amounts of the blue light BL, the green light GL, and the red light RL that form 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 misregistration elimination work is not performed, and the light source device 13 is shipped with each of the focal positions BFP, GFP, and RFP misaligned as in FIG. As described above, the tint 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 entrance end 61 changes due to individual differences. When the incident end 61A is at the focus position RFP of the red light RL as in the light guide 55A of the endoscope 11A, the display image 130R that is entirely reddish is generated. When the incident end 61B is at the focus position GFP of the green light GL as in the light guide 55B of the endoscope 11B, a display image 130G that is entirely greenish is generated and the light of the endoscope 11C is displayed. When the incident end 61C is at the focus 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, with respect to a plurality of types of endoscopes 11D and 11E having different specifications, if the positional relationship between the condenser lens 80 and the incident end 61 is different from each other, the endoscope 11D and the endoscope 11E are different. And the color of the displayed image changes.

On the other hand, in the present embodiment, as shown in FIG. 20, the focus 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 misregistration elimination work. In the endoscopes 11A to 11C, even if the positional relationship between the condenser 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 varies. As a result, the display image 130 whose color tone does not change is generated. Although illustration is omitted, the same applies when a plurality of types of endoscopes 11D and 11E having different specifications are used. Therefore, the color tone of the display image does not change each time endoscopic diagnosis is performed, and the operator can smoothly perform endoscopic diagnosis without feeling discomfort.

When the semiconductor light sources 35 to 37 are used, since the semiconductor light sources 35 to 37 having the rectangular light emitting portion are used, the condensed image of each color light emitted from the condenser lens 80 also has a rectangular shape. In this 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 when the condensed image is circular. Therefore, the adjusting mechanisms 81 and 82 of the present invention are particularly useful in the light source device 13 including the semiconductor light sources 35 to 37 having such rectangular light emitting portions.

In the above-described embodiment, the collimating lenses 75 and 77 are provided with the adjusting mechanisms 81 and 82. However, in the optical paths from the semiconductor light sources 35 to 37 to the condensing lens 80, the adjusting mechanisms are provided more than the dichroic mirrors 78 and 79. It may be provided on the semiconductor light sources 35 to 37 side. For example, as shown in FIGS. 21 and 22, adjusting mechanisms 131 and 132 may be provided to the blue semiconductor light source 35 and the red semiconductor light source 37 instead of or in addition to the collimating lenses 75 and 77. In this case, the adjusting 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 an adjusting mechanism is provided for the blue semiconductor light source 35 and the red semiconductor light source 37 in addition to the collimator lenses 75 and 77, only the collimator lenses 75 and 77, or the blue semiconductor light source 35 and the red color shown in FIG. The adjustment allowance can be earned more than the case where only the semiconductor light source 37 is used.

However, unlike the collimator lens, the semiconductor light source is connected with a member such as a wiring that may hinder the movement in the optical axis OA direction. Therefore, unlike the above-described embodiment, the semiconductor light source does not have an adjusting mechanism. It is preferable to provide an adjusting mechanism only on the collimator lens and move the collimator lens 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 one collimator lens 75 to 77 constitutes the first optical system has been described, but the first optical system may be constituted by a plurality of optical members. Similarly, the second optical system may be composed of a plurality of optical members instead of the single condenser lens 80 exemplified in the above embodiment. When the first optical system is composed of a plurality of optical members, the adjusting mechanism may be provided in at least one of the plurality of optical members.

In the above-described embodiment, the focus position BFP of the blue light BL and the focus position RFP of the red light RL are matched with the focus position GFP of the green light GL with the focus position GFP of the green light GL as a reference. The focus position BFP or the focus position RFP of the red light RL may be used as a reference. When the focus 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 focus 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-described embodiment, the color misregistration elimination work is performed at the time of the final inspection before the shipment of the light source device 13, but the timing of performing the color misregistration elimination work is not particularly limited. For example, after the light source device 13 is shipped, the worker may carry the detection unit 120 to the customer to carry out the color misregistration elimination work in response to the customer's request.

The adjusting mechanism is not limited to the configuration illustrated 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-described embodiment. Further, as the moving mechanism, a well-known moving mechanism such as a ball screw, a push-pull bolt, an eccentric cam or the like, which converts a rotary motion into a linear motion, may be used instead of the elongated hole 92 of the above embodiment. Further, the fixing mechanism may also be configured by 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 can guide the movement of the optical member such as the collimator 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 illustrated as the monochromatic semiconductor light source, but as shown in FIG. 23, a purple wavelength band for emphasizing and observing superficial blood vessels. A purple semiconductor light source 135 that emits the 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 violet 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 violet semiconductor light source 135 has a wavelength component in the vicinity of 380 nm to 420 nm, which is a violet wavelength band, for example, and emits violet light VL having a center wavelength of 405±10 nm and a half width of 20±10 nm.

The optical system group 136 includes, in addition to the optical system group 41 of the above-described embodiment, a collimating lens 137 that transmits the violet light VL to make the violet light VL substantially parallel, and a dichroic mirror 138 that couples the optical paths of the blue light BL and the violet light VL. This is the added configuration. The blue semiconductor light source 35 and the violet semiconductor light source 135 are arranged such 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 in a posture inclined by 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 characteristic of reflecting light in the violet wavelength band of less than about 430 nm and transmitting light in the blue, green, and red wavelength bands beyond that. The dichroic mirror 138 transmits the blue light BL from the blue semiconductor light source 35 to the downstream side and reflects the violet light VL from the violet semiconductor light source 135. Thereby, 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 a characteristic that the dichroic mirror 79 reflects light in the blue wavelength band of less than about 480 nm as described above, and thus is reflected by the dichroic mirror 79 and travels to the condenser lens 80. .. Thereby, the optical paths of all the blue light BL, the green light GL, the red light RL, and the 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-described embodiment. The adjusting mechanism 139 moves the collimator lens 137 in the optical axis OA direction to match the focal position of the purple light VL with the focal position of the blue light BL, the green light GL, and the red light RL.

As is well known, the reflectance of the superficial blood vessels greatly drops in the wavelength band below 450 nm, and drops most near 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 other portions can be obtained.

Further, the light scattering characteristics 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 mucosal surface layer of the living tissue, and the less light reaches the middle and deep layers. Therefore, the shorter the wavelength, the lower the depth of penetration, and the longer the wavelength, the higher the depth of penetration.

The violet light VL having a central wavelength of 405±10 nm emitted from the violet semiconductor light source 135 has a relatively short wavelength and a low depth of penetration, and therefore is absorbed by the superficial blood vessels. Therefore, the purple light VL can be used as special light for surface layer blood vessel enhancement. By using the purple light VL, it is possible to obtain a display image in which the superficial blood vessels are depicted with high contrast.

When observing the superficial blood vessels in an emphasized manner, the purple semiconductor light source 135 is turned on in addition to the semiconductor light sources 35 to 37 at the timing of the accumulation operation of the image sensor 56. When each of the semiconductor light sources 35 to 37, 135 is turned on, the purple light VL is added to the white light WL of the above-described embodiment, and the mixed light (WL+VL) of these lights is applied to the observation target as illumination light.

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

In this case, the B image signal contains the reflected light component corresponding to the purple light VL in addition to the reflected light component corresponding to the blue light BL forming the white light WL. It is depicted in contrast. In lesions such as cancer, the surface blood vessels have a characteristic that the density of the surface blood vessels tends to be higher than that in normal tissues. Therefore, when the purple semiconductor light source 135 is added, the surface blood vessels can be clearly visualized. This is preferable because it makes it easier to identify the lesion.

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

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 the semiconductor light sources 35 to 37 set by the exposure control so that the light amount becomes the target value. Finely adjust the drive current value. In this way, the light amount of each color light is constantly monitored by the light amount measuring sensor, and the drive current value given based on the measurement result of the light amount is finely adjusted, whereby the light amount can be controlled so as to always follow the target value. Therefore, it is possible to more stably obtain the illumination light having the target emission spectrum.

In the above embodiment, the semiconductor light source composed of only the LED is cited, but for example, the green semiconductor light source is excited by the blue excitation light LED that emits the blue excitation light in the wavelength band from purple to blue, and the blue excitation light. It is also possible to use 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, a red semiconductor light source is used as a blue excitation light LED that emits blue excitation light in the wavelength band of purple to blue, and red fluorescence in the wavelength band of red that is excited by the blue excitation light. It 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 the blue excitation light emitting element that emits blue excitation light in the wavelength band of violet to blue, and the green light that emits green excitation light in the green wavelength band. It may be an excitation light emitting element. In this case, a fluorescent substance is enclosed in the cavity 76 shown in FIGS. 5 and 6 instead of the resin 78 to form a fluorescent semiconductor light source.

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 shell-shaped case in which the microlens is formed instead of the surface mounting 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 these 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 through 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 modifications can be made. For example, a dichroic mirror having a dichroic filter formed on a transparent glass plate is used as an optical member forming the third optical system, but a dichroic prism having a dichroic filter formed on a prism may be used instead. Further, instead of an optical member such as a dichroic mirror or a dichroic prism formed with a dichroic filter, 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 are provided. The optical paths may be combined using a branched light guide having a. The branch type light guide is one in which an optical fiber is divided into a plurality of predetermined numbers at one end, and the incident end is branched into a plurality. In this case, each semiconductor light source is arranged corresponding to each branched incident end.

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

In the above embodiment, as the image sensor 56, a color image sensor that color-separates illumination light by B, G, and R micro color filters is illustrated, and the B, G, and R image signals are simultaneously acquired by the color image sensor. The simultaneous endoscope system and the light source device used for the simultaneous endoscope system have been described as an example. However, a monochrome image sensor is provided, and blue, green, and red color lights are sequentially irradiated to generate B, G, and R image signals. The present invention may be applied to a frame-sequential endoscope system that acquires a frame sequentially and a light source device used for the system.

In the above embodiment, an example in which the light source device and the processor device are separately configured has been described, but these devices may be integrally configured. Further, the present invention provides an endoscope system using a fiberscope that guides reflected light of illumination light to be observed by an image guide, or an ultrasonic endoscope having an imaging sensor and an ultrasonic transducer built in a distal end portion. And the light source device used therefor.

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 (3rd 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 intensity waveform of blue light GW Light intensity waveform of green light RW Light intensity waveform of red light

Claims (11)

In an endoscope light source device that supplies illumination light to a light guide of an endoscope,
A plurality of monochromatic semiconductor light sources that respectively emit light of a plurality of colors as the illumination light,
A plurality of first optical systems configured of at least one optical member, each of which transmits the light of the plurality of colors from the plurality of monochromatic semiconductor light sources,
A second optical system that collects the light of the plurality of colors that has passed through the plurality of first optical systems at an incident end of the light guide;
A position adjusting mechanism for adjusting the position of the optical member in the optical axis direction of the first optical system,
The position adjusting mechanism adjusts the position of the optical member so as to match the peaks of the light amount waveforms of the respective colored lights indicating the focal position of the respective colored lights,
The position adjusting mechanism, a guide mechanism for guiding the movement of the optical member in the optical axis direction,
A light source device for an endoscope, comprising: a moving mechanism that moves the optical member in the optical axis direction. The light source device for an endoscope according to claim 1, wherein the position adjusting mechanism is provided in the same number as the number of lights of the remaining colors other than the light of one color among the lights of the plurality of colors. .. A third optical system is provided between the plurality of first optical systems and the second optical system, and includes a third optical system that couples optical paths of the lights of the plurality of colors that have passed through the plurality of first optical systems. The light source device for an endoscope according to claim 1. The position adjusting mechanism is provided closer to the monochromatic semiconductor light source side than the third optical system in an optical path from the monochromatic semiconductor light source to the second optical system. Light source device for endoscopes. The light source device for an endoscope according to any one of claims 1 to 4, wherein each of the plurality of monochromatic semiconductor light sources has a rectangular light emitting portion. The plurality of monochromatic semiconductor light sources are a blue semiconductor light source, a green semiconductor light source, and a red semiconductor light source that respectively emit blue light, green light, and red light as the illumination light. The light source device for an endoscope according to any one of 5 above. The blue semiconductor light source emits the blue light having a central wavelength of 460±10 nm and a half width of 25±10 nm,
The green semiconductor light source emits the green light having a central wavelength of 550±10 nm and a half width of 100±10 nm,
7. The light source device for an endoscope according to claim 6, wherein the red semiconductor light source emits the red light having a center wavelength of 625±10 nm and a half width of 20±10 nm. 8. The endoscope light source according to claim 1, wherein the position adjusting mechanism adjusts the position of the monochromatic semiconductor light source in addition to the optical member in the optical axis direction. apparatus. A housing having a lens holder for holding the optical member,
The moving mechanism moves the optical member in the lens holder in the optical axis direction by using an elongated hole provided in the lens holder,
The guide mechanism guides the movement of the optical member in the lens holder in the optical axis direction by a guide protrusion provided on the lens holder and a guide groove formed on the housing,
The fixing mechanism fixes the position of the optical member in the lens holder by pressing the lens holder by a fixing portion with the lens holder fitted in a fitting hole in the housing. The light source device for an endoscope according to any one of 1 to 8. The position adjustment mechanism, the peak of the light amount waveform of the green light indicating the focus position of the green light, the peak of the light amount waveform indicating the focus position of the blue light, and the light amount waveform indicating the focus position of the red light The light source device for an endoscope according to claim 1, wherein the position of the optical member is adjusted so as to coincide with the peak. An endoscope having a light guide for guiding illumination light,
An endoscope light source device that supplies the illumination light to a light guide,
In an endoscope system in which a plurality of endoscopes are shared by a single endoscope light source device,
The light source device for an endoscope is
A plurality of monochromatic semiconductor light sources that respectively emit light of a plurality of colors as the illumination light,
A plurality of first optical systems configured of at least one optical member, each of which transmits the light of the plurality of colors from the plurality of monochromatic semiconductor light sources,
A second optical system that collects the light of the plurality of colors that has passed through the plurality of first optical systems at an incident end of the light guide;
A position adjusting mechanism for adjusting the position of the optical member in the optical axis direction of the first optical system,
The position adjusting mechanism adjusts the position of the optical member so as to match the peaks of the light amount waveforms of the respective colored lights indicating the focal position of the respective colored lights,
The position adjusting mechanism, a guide mechanism for guiding the movement of the optical member in the optical axis direction,
An endoscope system having a moving mechanism that moves the optical member in the optical axis direction.

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