JP2875802B2 - Light source device for endoscope - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a light source device for an endoscope which can supply various plane-sequential illumination lights so that various images having different observation wavelength ranges and the like can be obtained. .

[Problems to be solved by conventional technology and invention] In recent years, by inserting an elongated insertion portion into a body cavity,
2. Description of the Related Art Endoscopes capable of observing organs in a body cavity and the like and performing various treatments using a treatment tool inserted into a treatment tool channel as necessary are widely used.

Also, various electronic endoscopes using a solid-state imaging device such as a charge-coupled device (CCD) as an imaging unit have been proposed.

By the way, it is known that knowing the amount of hemoglobin in blood and the distribution of oxygen saturation is useful for early detection of a lesion and the like. As a method of determining the amount of hemoglobin and oxygen saturation in blood, for example, as shown in Japanese Utility Model Application Laid-Open No. 151705/1986, it is determined from images of a plurality of specific wavelength regions related to hemoglobin in blood. There is a way.

However, in the camera shown in the conventional example, since the observation wavelength region is fixed, an image in the visible region is not generally obtained, and optimal observation is performed according to an observation site, an observation purpose, and the like. Could not.

In the case of an endoscope apparatus that performs imaging in a frame sequential manner, it is possible to obtain the above-described special image by changing the wavelength region of the frame sequential illumination light. In this light source device, a rotary filter that separates the illumination light in a time-series manner is fixed in the illumination light path. Therefore, in order to switch the type of the illumination light, the light source device has to be changed.

The present applicant has proposed a light source device in which a rotary filter is made detachable in Japanese Patent Application No. 62-110054 previously filed. If this light source device is used, a normal color image and a special image can be obtained by exchanging the rotation filter. However, the operation of exchanging the rotation filter is necessary, and a plurality of images having different illumination lights are required. In the case of comparison, the operation is complicated, and it is difficult to switch images immediately.

[Object of the Invention] The present invention has been made in view of the above circumstances, and provides an endoscope light source device capable of supplying various plane-sequential illumination lights without replacing a rotary filter. It is intended to be.

[Means for Solving the Problems] A light source device for an endoscope according to the present invention is a light source device for an endoscope capable of supplying illumination light suitable for an endoscope provided with a frame sequential imaging means. A first rotation filter having a light source, three component filters for separating light emitted from the light source into three wavelength regions capable of forming a color image in time series, and the first rotation filter. And three component filters provided at positions corresponding to the respective component filters to limit the transmission wavelength region of the respective component filters of the first rotary filter, and provided at positions between the three component filters. A second rotation filter having a transmission portion that does not limit the three transmission wavelength regions, and rotating substantially coaxially with the first rotation filter; and rotating the first rotation filter and the second rotation filter. Rotating The filter may be stopped with the transmission portion interposed in the illumination light path, or the three component filters of the first rotary filter and the transmission portion of the second rotary filter may be simultaneously placed in the illumination light path. A first state in which both rotating filters are synchronously rotated so as to be positioned, and the three component filters of the first rotating filter and the three component filters of the second rotating filter are simultaneously in the illumination light path. To a second state in which both rotating filters are rotated synchronously so that they are located within
And a rotation control means capable of controlling the rotations of these two rotation filters.

[Operation] In the present invention, when the first and second rotary filters are controlled such that the respective component filters of the first rotary filter and the transmission section of the second rotary filter are both interposed in the illumination optical path, Surface-sequential light separated in time series by each component filter of the first rotary filter is output, while each component filter of the first rotary filter and the corresponding component of the second rotary filter are output. When the first and second rotary filters are controlled so that both filters are interposed in the illumination optical path, the wavelength region transmitted through the component filters of the first rotary filter and the component filters of the second rotary filter is changed. Limited face-sequential light is output. Note that, in the present invention, the rotation control means includes a case where the second rotation filter is controlled to be stopped.

Embodiment An embodiment of the present invention will be described below with reference to the drawings.

1 to 9 relate to a first embodiment of the present invention, FIG. 1 is an explanatory view showing the structure of a light source device, FIG. 2 is a side view showing the entire oblique mirror device, and FIG. FIG. 4 is a block diagram showing a configuration of an endoscope apparatus, FIG. 5 is an explanatory diagram showing a first rotating filter for normal observation,
FIG. 6 is an explanatory view showing a second rotation filter for a special image, FIG. 7 is an explanatory view showing transmission characteristics of each filter of the first rotation filter, and FIG. 8 is each filter of the second rotation filter. FIG. 9 is an explanatory diagram showing a change in the absorbance of blood due to a change in the oxygen saturation of hemoglobin.

As shown in FIG. 2, an electronic endoscope 1 connected to the light source device of the present embodiment has an elongated and flexible insertion portion 2, for example, and a large diameter An operation unit 3 is provided in series. A flexible cable 4 extends laterally from a rear end of the operation unit 3, and a connector 5 is provided at a distal end of the cable 4. The connector 5 is connected to a connector receiver 8 of a video processor 6 in which a light source device and a signal processing circuit are built. Further, a monitor 7 is connected to the video processor 6.

On the distal end side of the insertion portion 2, a rigid distal end portion 9 and a bending portion 10 which can be bent rearward adjacent to the distal end portion 9 are sequentially provided. By rotating a bending operation knob 11 provided on the operation section 3, the bending section 10 is rotated.
Can be bent in the horizontal direction or the vertical direction. The operation section 3 is provided with an insertion port 12 communicating with a treatment instrument channel provided in the insertion section 2.

As shown in FIG. 4, a light guide 14 for transmitting illumination light is inserted into the insertion section 2 of the electronic endoscope 1. The distal end surface of the light guide 14 is arranged at the distal end 9 of the insertion section 2 so that illumination light can be emitted from the distal end 9. The light guide 14 has an incident end inserted into the universal cord 4 and connected to the connector 5. Further, an objective lens system 15 is provided at the distal end portion 9, and a solid-state imaging device 16 is provided at an image forming position of the objective lens system 15. Signal lines 26 and 27 are connected to the solid-state imaging device 16. These signal lines 26 and 27 are inserted into the insertion section 2 and the universal cord 4 and connected to the connector 5.

On the other hand, a light source device 50 is provided in the video processor 6, and light emitted from the light source device 50 is incident on an incident end of the light guide 14, and is guided to the distal end portion 9 via the light guide 14. He is emitted from the tip 9 and
The observation site is illuminated.

The return light from the observation site due to the illumination light is imaged on the solid-state imaging device 16 by the objective lens system 15, and is photoelectrically converted. This solid-state imaging device 16 includes:
A driving pulse from a driver circuit 31 in the video processor 6 is applied via the signal line 26, and reading and transferring are performed by the driving pulse. The video signal read from the solid-state imaging device 16 is
The signal is input to a preamplifier 32 provided in the video processor 6 or the electronic endoscope 1 via the signal line 27. The video signal amplified by the preamplifier 32 is input to a process circuit 33, subjected to signal processing such as γ correction and white balance, and is subjected to an A / D converter 34.
Is converted into a digital signal. The digital video signal is supplied by a select circuit 35 to three memories (1) 36a, memories (2) 36b, and memories (3) corresponding to, for example, each color of red (R), green (G), and blue (B). 36c is selectively stored. The memory (1) 36a, the memory (2) 36b, and the memory (3) 36c
Are read out at the same time, converted into analog signals by the D / A converter 37, output as R, G, B color signals, input to the encoder 38, and output as NTSC composite signals from the encoder 38. It has become.

Then, the R, G, B color signal or the NTSC composite signal is input to a color monitor 7, and the color monitor 7 displays an observation region in color.

In addition, the motor driver 25, the driver circuit 31, and the selection circuit are provided by various synchronization signals from the periodic signal generation circuit 42.
Synchronization between circuits such as 35 and encoder 38 is established.

The light source device 50 is configured as shown in FIG.

The light source device 50 includes a lamp 21 that emits white light, and an illumination optical path between the lamp 21 and the incident end of the light guide 14 includes a first light for normal observation in order from the lamp 21 side.
Rotation filter 51 and second rotation filter 52 for special images
And are arranged. The rotary filters 51 and 52 are rotated by motors 53A and 53B, respectively. Photosensors 54A and 54B for detecting the rotational position are provided opposite to the filters 51 and 52, respectively. Further, on the second rotary filter 52 side, this rotary filter is further provided.
Opposite to 52, photo sensors 55a and 55b for detecting a stop position
Are arranged.

The first rotary filter 51, the second rotary filter 52
Are configured as shown in FIGS. 5 and 6, respectively. FIGS. 5 and 6 are views of the rotary filter as viewed from the emission side.

As shown in FIG. 5, the first rotating filter 51 includes filters 51a, 51b, and 51c that transmit light in each of red (R), green (G), and blue (B) wavelength regions in the circumferential direction. Are arranged along. The respective wavelength ranges of R, G and B are shown in FIG. A rotation position detection mark 58A is formed on the inner peripheral side of each of the filters 51a, 51b, 51c. The photo sensor 54A detects the mark 58A.

On the other hand, as shown in FIG. 6, filters 52a, 52b, and 52c that transmit the narrowband R ', G', and B 'wavelength regions are provided in the second rotation filter 52 along the circumferential direction. While being arranged, a white light (W) is provided between each of the filters 52a, 52b, 52c.
There is provided a white light transmitting portion 52W that transmits light. still,
Each of the wavelength regions R ', G', and B 'has a narrow band centered at 450 nm, 500 nm, and 650 nm, as shown in FIG. 8, for example.

Reflector plates 56a and 56b facing the photosensors 55a and 55b are provided on the outer peripheral portion of each white light transmitting portion 52W, respectively. As shown in FIG. 6, the photo sensors 55a, 55
b is arranged so that the photosensor 55a is located outside the second rotary filter 52 along the radial direction. On the other hand, the reflection plates 56a and 56b are arranged such that the outer reflection plate 56a is shifted in the left rotation direction with respect to the inner reflection plate 56b. Further, each of the filters 52a, 52b, 52
On the inner peripheral side of c, a rotational position detection mark 58B is formed. The photo sensor 54B detects the mark 58B.

In the present embodiment, the first rotary filter 51, the motor 53
A, the photo sensor 54A is stored in the filter cassette 60A, and the second rotary filter 52, the motor 53B, and the photo sensors 54B, 55a, 55b are stored in the filter cassette 60B. As shown in FIG. 3, each filter cassette 60A, 60B
The light source device 5 in the video processor 6 is opened through openings 59A and 59B provided on the upper surface of the video processor 6, for example.
It can be attached to and detached from 0. The filter cassettes 60A and 60B are provided with windows 61A and 61B at positions corresponding to the illumination light path, respectively. Further, on the outer peripheral portions of the packages of the filter cassettes 60A and 60B, electric contacts 62 for connecting the motors 53A and 53B, the photo sensors 54A, 54B, 55a and 55b, and the circuits in the light source device 50 are provided.
A and 62B are provided.

As shown in FIG. 1, a driver 63A for driving the motor 53A is provided in the light source device 50. The output of the phase control circuit 65A and the output of the speed control circuit 66A are added to the driver 63A by the adder 67A and input. The phase control circuit 65A is configured to receive a phase signal from the photosensor 54A, and a vertical synchronization signal VD and a subcarrier SC from the synchronization signal generation circuit 42 as reference signals. And this phase control circuit
The 65A compares the phase of the phase signal from the photo sensor 54A with the reference signal and outputs a signal corresponding to the phase difference. Further, the speed control circuit 66A receives a speed signal FG from a speed sensor (not shown) provided in the motor 53A and a subcarrier SC from the synchronization signal generation circuit 42 as a reference signal. I have. And
The speed control circuit 66A outputs a signal corresponding to a speed difference from a reference speed. In this way,
The first rotary filter 51 is controlled to rotate by phase synchronization control using speed control.

Similarly, a driver 63B for driving the motor 53B is provided in the light source device 50. This driver 63B
The output of the adder 67B for adding the output of the phase control circuit 65B and the output of the speed control circuit 66B, and the photosensors 55a and 55b
One of the outputs of the gate circuit 63 to which the output of the gate circuit 63 is input is selectively input via the switch 69.
That is, the gate circuit 68 is connected to one input terminal 69a of the two-input switch 69, and the other input terminal 69b is connected to the gate circuit 68.
The adder 67B is connected, and the output terminal 69c is connected to the driver 63B. The phase control circuit 65B is configured to receive the phase signal from the photosensor 54B, the phase signal from the photosensor 54A, and the subcarrier SC from the synchronization signal generation circuit 42 as a reference signal. The phase control circuit 65B compares the phase of the phase signal from the photosensor 54B with the reference signal and outputs a signal corresponding to the phase difference. Further, the speed control circuit 66B receives a speed signal FG from a speed sensor (not shown) provided in the motor 53B, and a subcarrier SC from the synchronization signal generation circuit 42 as a reference signal. I have. The speed control circuit 66B outputs a signal corresponding to a speed difference from a reference speed. Therefore, when the input terminal 69b is selected by the switch 69, the second rotation filter 52
The rotation filter 51 and the phase are synchronized and rotated. In this case, the filters 52a, 52b, 52c transmitting the R ', G', B 'of the second rotary filter 52 are replaced with the filters 51a transmitting the R, G, B of the first rotary filter 51. ,Five
The phase is controlled so as to overlap with 1b and 51c.

On the other hand, when the input terminal 69a side is selected by the switch 69, the second rotary filter 52 has the white light transmitting portion 52W interposed in the illumination optical path based on the output of the gate circuit 68. It stops at the position.

The operation of the gate circuit 68 will be described with reference to FIG. In the gate circuit 68, the photo sensor 55a is
Is detected, and when the photo sensor 55b does not detect the reflection plate 56b, a signal for rotating the rotation filter 52 clockwise is output. When the photo sensor 55a does not detect the reflection plate 56a and the photo sensor 55b detects the reflection plate 56b, a signal for rotating the rotation filter 52 counterclockwise is output. When both the photo sensors 55a and 55b detect the reflection plates 56a and 56b, the photo sensors 55a and 55b output a signal for stopping the rotation filter 52. When the two photosensors 55a and 55b do not detect the reflection plates 56a and 56b, they output a signal for rotating the rotation filter 52 clockwise. For example, when the input end 69a is selected by the switch 69 while the rotation filter 52 is rotating counterclockwise, first, only the photo sensor 55a detects the reflection plate 56a. Therefore, the gate circuit 68 outputs a signal for rotating the rotation filter 52 clockwise. As a result, the rotation filter 52 is decelerated, and when the photo sensors 55a and 55b stop at the position where the reflection plates 56a and 56b are detected, the photo sensors 55a and 55b are held at that position. When the stop position is passed by inertia, only the photo sensor 55b detects the reflection plate 56b, and the rotary filter 52 is rotated counterclockwise and returned to the stop position again. In this way, the rotary filter 52 is stopped at a predetermined stop position, that is, at a position where the white light transmitting section 52W is interposed in the illumination light path.

In the present embodiment configured as described above, when performing normal observation, the first rotary filter 51 is rotated by controlling the phase, and the switch 69 selects the input terminal 69a side. Then, the second rotation filter 52 is connected to the white light transmitting section.
52W stops at the position where it is interposed in the illumination light path. Therefore,
The light emitted from the lamp 21 passes through the first rotating filter 51.
The light is separated in time series into light of each wavelength region of R, G, and B, passes through the white light transmitting portion 52W of the second rotating filter 52, and is incident on the light guide 14 incidence end. Then, the R, G, and B lights are transmitted to the distal end portion 9 via the light guide 14 and illuminate the subject. The return light from the subject due to the R, G, B plane-sequential illumination light in this visible range is reflected by the objective lens system 15.
Thus, an image is formed on the solid-state imaging device 16, and a subject image is captured by the solid-state imaging device 16. Therefore, monitor 7
, A normal visible image is displayed in color.

On the other hand, when observing a special image in the wavelength region of R ', G', B ', the first rotating filter 51 is rotated by controlling the phase, and the switch 69 selects the input terminal 69b side. Then, the second rotation filter 52 outputs R ′, G ′,
Each of the filters 52a, 52b, and 52c transmitting B 'is phase-controlled and rotated so as to overlap with each of the filters 51a, 51b, and 51c transmitting R, G, and B of the first rotating filter 51. Therefore, the lamp
Light emitted from 21 is filtered by a first rotating filter 51 into R, G,
The light of R, G, B is separated in time series into light of each wavelength region of B, and the light of R, G, B is
The light passes through 52b and 52c, is limited to the wavelength region of R ', G', and B ', and is incident on the light guide 14 incident end. In this case, an image in the wavelength range of R ', G', B 'is displayed on the monitor 7 in a pseudo color.

Further, as shown in FIG. 9, since the difference in absorbance of hemoglobin is large between around 500 nm and around 650 nm,
From the G ′ and R ′ images, changes in the amount of hemoglobin can be observed.

The oxygen saturation of hemoglobin (hereinafter referred to as SO ₂ ) is defined as a narrow-band wavelength region of the second rotation filter 52.
Region where the change in blood absorbance is small due to changes in
By setting a region near 450 nm and a region where the absorbance of blood changes due to a change in SO ₂ , for example, around 530 nm, it is possible to observe the change in SO ₂ with images in both wavelength regions.

The opening angle of the white light transmitting portion 52W of the second rotary filter 52 is different from that of the first rotary filter 51 and the second rotary filter.
52 is rotated so as to be controlled in phase so that the white light transmitting portion 52W of the second rotating filter 52 and the filters 51a, 51b, 51c of the first rotating filter do not overlap. ing.

As described above, according to this embodiment, by switching the rotation / stop of the second rotary filter 52 by the switch 69, the field sequential light for normal observation and the special image for the special image can be obtained without replacing the rotary filter. , And can be supplied by switching between the lights.

Further, a first rotation filter 51, a second rotation filter 52
However, both are housed in the filter cassettes 60A and 60B and are detachable, so that a switchable combination can be arbitrarily selected by preparing various filter cassettes.

In addition, both the filter cassettes 60A and 60B are
When it is removed from the endoscope, white light can be output, and suitable illumination light can be supplied even to an endoscope capable of visual observation such as a fiberscope or an endoscope having a simultaneous imaging means. it can.

Note that a plurality of second rotary filters 52 may be provided so that three or more types of plane-sequential light can be supplied. In this case, of the plurality of second rotation filters, a desired rotation filter is rotated in phase synchronization with the first rotation filter, and the other rotation filters are rotated at a position where the white light transmitting portion is interposed in the illumination optical path. Just stop it.

Note that the white light transmitting portion 52W of the second rotary filter 52 may be a hole.

FIG. 10 is an explanatory view showing a light source device according to a second embodiment of the present invention.

In the light source device 70 of the present embodiment, the second rotation filter 52
Are not provided with the reflection plates 56a and 56b for detecting the stop position, and are not provided with the photo sensors 55a and 55b for detecting the reflection plates 56a and 56b. Further, the gate circuit 68 and the switch 69 are not provided, and the adder 67B is directly connected to the driver 63B. Also, a phase control circuit 65B for the second rotation filter 52
For this, a switching circuit 71 for switching the phase of the second rotary filter with respect to the first rotary filter 51 is provided.
Other configurations are the same as those of the first embodiment.

In the present embodiment, the second rotation filter 52 is always the first rotation filter.
Is rotated in phase synchronization with the rotary filter of
With 71, the phase of the second rotary filter with respect to the first rotary filter 51 can be switched. The filters 52a, 52b, and 52c that transmit R ', G', and B 'pass through the second rotation filter 52 and the R,
When the phase is controlled so as to overlap the filters 51a, 51b, 51c transmitting G and B, plane-sequential light of R ', G', and B 'is output.
On the other hand, the second rotating filter 52 is divided into three white light transmitting portions 52.
When the phase is controlled so that W overlaps each of the filters 51a, 51b, 51c transmitting the R, G, B of the first rotary filter 51, the normal
R, G, B plane-sequential light is output.

As described above, according to the present embodiment, the configuration is further simplified, and it is possible to more quickly switch between the field sequential light for normal observation and the field sequential light for a special image.

 Other functions and effects are the same as those of the first embodiment.

FIG. 11 is an explanatory view showing a rotary filter in the light source device according to the third embodiment of the present invention.

In this embodiment, the second rotary filter 72 is provided with filters 72a, 72b, and 72c that transmit R, G, and B at the positions of the three white light transmitting portions 52W of the rotary filter 52 in the second embodiment. It is something that was taken.

In the present embodiment, the second rotation filter 72 is set to R ', G',
When the phases of the filters 52a, 52b, 52c transmitting B 'are controlled so as to overlap the filters 51a, 51b, 51c transmitting R, G, B of the first rotary filter 51, R', G ', B ′ plane-sequential light is output. On the other hand, the second rotary filter 72 is formed by combining the filters 72a, 72b, 72c transmitting the R, G, B with the filters 51a, 51b, 51c transmitting the R, G, B of the first rotary filter 51. When the phases are controlled so as to overlap, plane-sequential light of R, G, and B is output.

Other configurations, operations, and effects are the same as those of the second embodiment.

It should be noted that the present invention is not limited to the above embodiments, and for example,
Only the rotating filter may be stored in the filter cassette, and the motor and the like may be fixed in the light source device. Also,
The rotating filter may be fixed in the light source device.

In addition, the present invention is not limited to an endoscope that receives reflected light of an object to be observed, but can also be applied to an endoscope that receives light transmitted through the object to be observed for observation.

In addition, the present invention is not limited to an electronic endoscope having a solid-state imaging device at the distal end of the insertion portion, and may be replaced with an eyepiece of an endoscope such as a fiberscope capable of observing the naked eye or with the eyepiece. Thus, the present invention can also be applied to an endoscope apparatus used by connecting a television camera.

[Effects of the Invention] As described above, according to the present invention, by controlling the rotation of the first and second rotary filters, it is possible to supply various plane-sequential illumination light without replacing the rotary filters. There is.

[Brief description of the drawings]

FIGS. 1 to 9 relate to a first embodiment of the present invention.
FIG. 2 is an explanatory view showing the configuration of the light source device, FIG. 2 is a side view showing the entire endoscope device, FIG. 3 is a perspective view of the video processor, and FIG. 4 is a block diagram showing the configuration of the endoscope device. , Fifth
FIG. 6 is an explanatory diagram showing a first rotating filter for normal observation, FIG. 6 is an explanatory diagram showing a second rotating filter for special images,
FIG. 7 is an explanatory diagram showing the transmission characteristics of each filter of the first rotation filter, FIG. 8 is an illustration showing the transmission characteristics of each filter of the second special image rotation filter, and FIG. FIG. 10 is an explanatory view showing a change in absorbance of blood due to a change in oxygen saturation, FIG. 10 is an explanatory view showing a light source device according to a second embodiment of the present invention, and FIG. 11 is a light source device according to a third embodiment of the present invention. It is explanatory drawing which shows a rotation filter. DESCRIPTION OF SYMBOLS 1 ... Electronic endoscope, 6 ... Video processor 50 ... Light source device 51 ... First rotary filter 52 ... Second rotary filter 52W ... White light transmitting part 53A, 53B ... Motor 63A, 63B …… Driver 65A, 65B …… Phase control circuit 69 …… Switch

──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Hiromasa Suzuki 2-43-2 Hatagaya, Shibuya-ku, Tokyo Inside O-limpus Optical Co., Ltd. (72) Inventor Kazunari Nakamura 2-4-2-3 Hatagaya, Shibuya-ku, Tokyo No. O-Limpus Optical Industry Co., Ltd. (72) Inventor Takeaki Nakamura 2-43-2 Hatagaya, Shibuya-ku, Tokyo In-Olympus Optical Industry Co., Ltd. (72) Inventor Yoshinao Daiaki 2-43, Hatagaya, Shibuya-ku, Tokyo No. 2 Within Olympus Optical Co., Ltd. (56) References JP-A-62-217216 (JP, A) (58) Fields investigated (Int. Cl. ⁶ , DB name) G02B 23/00

Claims (1)

(57) [Claims] 1. An endoscope light source device capable of supplying illumination light suitable for an endoscope provided with an image pickup device of a frame sequential type, comprising: a light source; Formable 3
A first rotary filter having three component filters separated in time series into three wavelength regions; and a first rotary filter provided at a position corresponding to each component filter of the first rotary filter. A three-component filter that limits the transmission wavelength region of each component filter, and a transmission section that is provided at a position between the three component filters and does not limit the three transmission wavelength regions, A second rotating filter that rotates substantially coaxially with the first rotating filter; and a second rotating filter that rotates the first rotating filter.
Or the three filter elements of the first rotating filter and the transmitting part of the second rotating filter simultaneously illuminate the rotary filter in a state where the transmitting section is interposed in the illumination optical path. A first state in which both rotary filters are rotated synchronously so as to be located in the optical path; three component filters of the first rotary filter and the second state;
And a second state in which both of the three filters are rotated in synchronization with each other so that the three component filters are simultaneously positioned in the illumination light path. A light source device for an endoscope, comprising: rotation control means.