JP2011050442A - Light source device and endoscope system - Google Patents

Abstract

Provided are a light source device and an endoscope system capable of emitting superimposed light with an appropriate amount of light without waiting for the light source to be turned off even at the time of start-up or restart from reset.
A plurality of LEDs arranged in an annular shape, an illumination optical system for guiding illumination light from the LEDs, a motor for rotating the illumination optical system around a central axis, and a light guide An image brightness calculation circuit 33 that detects the light intensity, a light source light amount calculation circuit 35 that calculates the light emission intensity of the LED 1 based on the detected light intensity, and a nonvolatile memory 24 that stores the calculated light emission intensity of the LED 1. And the write control circuit 25 for updating the light emission intensity of the LED 1 stored at a predetermined interval, and the update of the light emission intensity of the LED 1 is prohibited and stored when the motor 2 does not reach the constant speed rotation. A light source device including a controller that sequentially turns on the LEDs 1 with the latest emission intensity is employed.
[Selection] Figure 2

Description

  The present invention relates to a light source device including a plurality of light sources and an endoscope system including the same.

  2. Description of the Related Art Conventionally, a light source device that emits high-intensity superimposed light by sequentially illuminating light sources such as LEDs arranged in an annular shape with high output sequentially and rotating a light guide rod in accordance with the lighting cycle is known. (For example, refer to Patent Document 1).

JP 2004-71393 A

  In such a light source device, when adjusting the light emission intensity of the light source based on the brightness of the image of the imaging device or display device, that is, when performing automatic light control, in order to suppress the flicker of the color of the superimposed light, It is necessary to synchronize the imaging frame and the illumination frame so that their periods and phases coincide with each other.

  However, in order to match the period and phase of the imaging frame and the illumination frame, it is necessary to wait until the rotation speed of the light guide rod becomes constant. Therefore, at the time of starting the light source device or restarting from reset, the light source is turned off until the rotation speed of the light guide rod becomes constant. For this reason, when such a light source device is used in an endoscope system, there is a disadvantage in that the diagnosis and treatment are hindered if the extinguishing time by resetting is long.

  Further, when the number of rotations of the light guide rod becomes constant, the light source has been turned off until then, and automatic light control is performed based on a dark image acquired during that time. Therefore, the light source emits light at full power, and the image is overexposed, resulting in a problem that the image quality is significantly reduced.

  The present invention has been made in view of the above-described circumstances, and can emit superimposed light with an appropriate amount of light without waiting for the light source to be turned off even at the time of start-up or restart from reset. An object of the present invention is to provide a light source device and an endoscope system.

In order to achieve the above object, the present invention employs the following means.
According to a first aspect of the present invention, a plurality of light sources arranged in a ring at a predetermined interval and arranged with an optical axis directed inward in the radial direction of the ring, and illumination light emitted from the light source A light guide portion that is arranged with a light incident surface facing outward in a radial direction of the ring, and that guides illumination light incident on the light incident surface in a direction along a central axis of the ring, and the light guide A rotation unit that rotationally drives a portion around the central axis, a light detection unit that detects the intensity of light guided by the light guide unit, and the light source based on the intensity of light detected by the light detection unit An emission intensity calculation unit for calculating the emission intensity of the light source, a storage unit for storing the emission intensity of the light source calculated by the emission intensity calculation unit, and the emission intensity of the light source stored in the storage unit at predetermined intervals. Update means for updating, and a control unit for controlling the light source and the update means, The control unit prohibits the updating unit from updating the light emission intensity of the light source to the storage unit when the rotating unit has not reached constant speed rotation, and the latest light emission stored in the storage unit. It is a light source device that sequentially pulses the light source facing the incident surface with intensity.

  According to the first aspect of the present invention, the light guide unit is rotated around the central axis by the rotating unit, and the light source facing the incident surface of the light guide unit is sequentially pulsed by the control unit. As a result, the high-intensity illumination light emitted from the light source can be continuously incident on the incident surface of the light guide, and can be emitted while being superimposed in the direction along the central axis of the ring.

  Further, the light emission intensity of the light source is calculated by the light emission intensity calculation unit based on the intensity of light detected by the light detection unit (for example, the brightness of the image of the imaging device or the display device). The light emission intensity is stored in the storage unit and updated at predetermined intervals by the updating unit, and the light source is caused to emit light with the updated light emission intensity. Thereby, based on the intensity | strength of the light detected by the light detection part, what is called automatic light control which adjusts the light quantity of the superimposition light inject | emitted by the light guide part can be performed.

  At this time, if the rotation unit has not reached constant speed rotation, the control unit prohibits the update unit from updating the light emission intensity of the light source to the storage unit, and the latest light emission stored in the storage unit. The light source is controlled to emit light with intensity. As a result, even when the rotating unit does not reach constant speed rotation, for example, when restarting due to an abnormal reset, the light source emits light with the latest emission intensity stored in the storage unit, that is, the emission intensity before restarting. Can be made. By doing in this way, the change of the light quantity of the superimposition light before and after restart can be made small, and it can prevent that the light quantity of superimposition light becomes too large or too small.

  In the above aspect, when the rotating unit reaches a constant speed rotation, the control unit starts updating the light emission intensity of the light source to the storage unit by the updating unit, and at the updated light emission intensity, The light source may emit light.

  Automatic dimming can be started by starting the update of the light emission intensity to the storage unit by the updating means. Here, when the rotation unit reaches a constant speed rotation, the imaging frame and the illumination frame can be synchronized, and their periods and phases can be matched. By starting the automatic light control in this state, it is possible to suppress flickering of the color of the superimposed light, and it is possible to emit the superimposed light having a stable color.

The said aspect WHEREIN: The said control part is good also as controlling the pulse width and drive current of the said light source according to the rotation speed of the said rotation part.
By controlling the pulse width and driving current of the light source according to the number of rotations of the rotating unit, the light emission intensity of the light source can be easily controlled.

A second aspect of the present invention is an endoscope system including any one of the light source devices described above and an imaging device that captures an area illuminated by the light source device.
According to such an endoscope system, since the above-described light source device is provided, observation can be started immediately without waiting for the light source to be turned off when the light source device is activated or restarted by resetting. Can do. At that time, it is possible to prevent the amount of superimposing light that illuminates the observation area from being excessively large or small, and to prevent the observation image from being overexposed or dark, thereby accurately Can be observed.

  According to the present invention, there is an effect that it is possible to emit superimposed light with an appropriate amount of light without waiting for the light source to be turned off even at the time of start-up or restart from reset.

It is a longitudinal cross-sectional view which shows schematic structure of the light source device which concerns on one Embodiment of this invention. It is a functional block diagram of the light source device of FIG. It is a figure explaining the relationship between the drive current of LED, and a pulse width. FIGS. 3A and 3B are diagrams illustrating a method of determining a drive signal by the drive signal instruction circuit of FIG. 2, in which FIG. 2A is 1 at the time of increasing rotation, FIG. 2B is at the time of increasing rotation 2, and FIG. It is a figure explaining the automatic light control at the time of steady rotation in the light source device of FIG. It is a timing chart of the conventional light source device. It is a timing chart of the conventional light source device. It is a figure explaining the automatic light control at the time of unsteady rotation in the conventional light source device. It is a figure explaining the automatic light control at the time of unsteady rotation in the light source device of FIG. It is a figure explaining the control method of the drive current and pulse width of LED in the light source device of FIG. It is a timing chart of the light source device of FIG.

Hereinafter, a light source device according to an embodiment of the present invention will be described with reference to the drawings.
FIG. 1 is a schematic diagram illustrating a schematic configuration of a light source device 10 according to the present embodiment.
As shown in FIG. 1, a light source device 10 includes a cylindrical base 8, a plurality of LEDs (light sources) 1 arranged in an annular shape on the inner peripheral surface of the base 8, and LEDs 1 arranged in an annular shape. The light guide member (light guide portion) 11 disposed radially inward, the rod base 3 that supports the light guide member 11, and the light guide member 11 and the rod base 3 are integrated around the central axis L of the ring. A motor (rotating unit) 2 that rotationally drives and a control unit (not shown) that controls these motors are provided.

  A plurality of LEDs 1 are arranged with a predetermined interval in the circumferential direction with the optical axis directed inward in the radial direction of the ring, and when a drive current is supplied from a power source (not shown), the radial direction of the ring Illumination light is emitted inward.

  The light guide member 11 has an incident surface 9 on which the illumination light emitted from the LED 1 is incident. The light guide rod 4 guides the illumination light incident on the incident surface 9 inward in the radial direction of the ring, A reflection prism 5 that reflects the illumination light guided by the light guide rod 4 in a direction along the center axis L of the ring, and a light that guides the illumination light reflected by the reflection prism 5 in a direction along the center axis L And a guide 6. By having such a configuration, the light guide member 11 emits illumination light emitted radially inward from the LED 1 in a direction along the central axis L.

The rod base 3 is a columnar member that rotatably supports the light guide member 11 around the central axis L in a state where the incident surface 9 of the light guide member 11 is disposed radially outward.
The motor 2 is disposed below the rod base 3 in the direction along the central axis L, and integrally rotates the light guide member 11 and the rod base 3 around the central axis L.

  A heat pipe 13 that recovers heat generated from the LED 1 and transmitted to the base 8 is provided on the outer peripheral surface of the base 8. Moreover, the heat pipe 13 is connected to the radiation fin 14 that performs heat exchange with the outside air. By having such a configuration, the heat generated from the LED 1 is dissipated outside the light source device 10 by the radiation fins 14 via the base 8 and the heat pipe 13.

FIG. 2 is a functional block diagram in which the functions of the light source device 10 are developed.
Here, a case where the light source device 10 according to the present embodiment is applied to an endoscope 50 including the imaging device 31 will be described. The endoscope 50 illuminates an object to be illuminated, images reflected light from the object to be illuminated by the imaging device 31, and controls the amount of illumination light based on the brightness of the screen. .

As shown in FIG. 2, the endoscope 50 includes an illumination system 20 that illuminates an object to be illuminated, and an imaging system 30 that captures reflected light from the object illuminated by the illumination system 20.
The illumination system 20 outputs a drive signal to the light source drive circuit 22 by referring to the light source unit 21 that emits illumination light, the light source drive circuit 22 that supplies a drive current to the light source unit 21, and the pulse width / current table 28. A drive signal instruction circuit 23, a nonvolatile memory (storage unit) 24 that outputs a light source light quantity instruction value to the drive signal instruction circuit 23, and a write control circuit (update means) 25 that writes the light source light quantity instruction value to the nonvolatile memory 24. ing. Here, the light source light quantity instruction value is an output value instructing the light emission intensity of the LED 1.

The light source unit 21 includes the above-described LED 1, illumination optical system 26, the above-described motor 2, and rotation detection means 27.
The illumination optical system 26 includes the light guide rod 4, the reflection prism 5, and the light guide 6 described above, and emits illumination light emitted from the LED 1 toward the object to be illuminated.

  The rotation detection means 27 is, for example, an optical sensor arranged with the optical axis facing the side surface of the motor 2, and detects a reflection plate (not shown) attached to a part of the side surface of the motor 2. ing. The rotation detection means 27 outputs a lighting timing signal to the light source drive circuit 22 based on a signal detected when the reflectors face each other, and also outputs a rotation speed signal of the motor 2 to the drive signal instruction circuit 23 and the write control circuit 25. Is output.

In the pulse width / current table 28, a preset current value of the LED 1 and a pulse width are recorded in association with each other.
Here, the relationship between the maximum value of the current value and the pulse width that can be driven without destroying the LED 1 is known to be able to increase the current value as the pulse width is reduced, as shown by the characteristic L in FIG. Yes. With reference to the pulse width / current table 28 in which this characteristic L is recorded, the drive signal instruction circuit 23 outputs a drive signal to the light source drive circuit 22.

  Further, the drive signal instruction circuit 23 is preset in the pulse width / current table 28 based on the rotation number signal output from the rotation detection means 27 and the latest light source light quantity instruction value written in the nonvolatile memory 24. A drive signal is output to the light source drive circuit 22 so that the LED 1 emits light with a current value and a pulse width.

A method of determining the drive signal by the drive signal instruction circuit 23 will be described below with reference to FIGS. 4 (a) to 4 (c). 4A to 4C, VS represents a current value during steady rotation, and VDC represents a rated current value.
As shown in FIGS. 4A and 4B, when the rotation of the motor 2 is increased, the current value V is larger than the rated current value VDC and smaller than the current value VS during steady rotation. In addition, the drive current of the LED 1 is controlled.

  On the other hand, as shown in FIG. 4C, when the motor 2 reaches the steady rotation speed, the pulse width is reduced and the current value V is increased until it matches the current value VS during steady rotation. By doing in this way, the electric current larger than a rated current can be instantaneously sent with respect to LED1, and bright light can be obtained instantaneously.

The nonvolatile memory 24 is a nonvolatile memory, and holds the latest light source light quantity instruction value output from the write control circuit 25.
The writing control circuit 25 updates the light source light quantity instruction value stored in the nonvolatile memory 24 based on the rotation number signal from the rotation detection means 27. Specifically, the writing control circuit 25 is prohibited from updating the light source light quantity instruction value to the nonvolatile memory 24 when the motor 2 has not reached the constant speed rotation. On the other hand, when the motor 2 reaches a constant speed rotation, the writing control circuit 25 updates the light source light quantity instruction value to the nonvolatile memory 24 at a predetermined interval.

  Based on the lighting timing signal output from the rotation detecting means 27, the light source driving circuit 22 sequentially turns on the LEDs 1 facing the incident surface 9 of the light guide rod 4 in pulses. At this time, the light source drive circuit 22 pulses the LED 1 based on the drive signal output from the drive signal instruction circuit 23, that is, the latest light source light quantity instruction value written in the nonvolatile memory 24.

  The imaging system 30 includes an imaging device 31, an image processing circuit 32, an image brightness calculation circuit (light detection unit) 33, an image brightness setting unit 34, and a light source light amount calculation circuit (emission intensity calculation unit) 35. I have.

  The imaging device 31 is an imaging element such as a CCD (Charge Coupled Device) or a CMOS (Complementary Metal Oxide Semiconductor), for example, and images an object to be illuminated. More specifically, the imaging device 31 converts reflected light from the object to be illuminated into an electrical signal by photoelectric conversion, and outputs the electrical signal to the image processing circuit 32 as an imaging signal.

  The image processing circuit 32 performs image processing on the imaging signal from the imaging device 31, that is, the image of the illumination object acquired by the imaging device 31, and outputs the processed image signal to the image brightness calculation circuit 33. .

  The image brightness calculation circuit 33 calculates image brightness such as an average brightness value and a brightness peak value from the image signal image-processed by the image processing circuit 32, and the light source light quantity calculation circuit 35 as an image brightness signal. To output.

  The image brightness setting means 34 is an input device such as a keyboard, for example. The image brightness setting means 34 can set the brightness of the image by the user's operation, and the set image brightness value is used as the light source light quantity calculation circuit 35. To output.

  The light source light quantity calculation circuit 35 is based on the image luminance signal output from the image brightness calculation circuit 33 and the image brightness value output from the image brightness setting means 34, that is, the light emission of the LED1. The intensity is calculated. Further, the light source light quantity calculation circuit 35 outputs the calculated light source light quantity instruction value to the write control circuit 25.

  By having the said structure, the automatic light control of the illumination light inject | emitted toward an to-be-illuminated object is performed. Specifically, the image brightness is calculated by the image brightness calculation circuit 33 from the image signal of the illumination object acquired by the imaging device 31, and the light quantity of the LED 1 is set so that the value becomes a predetermined image brightness value. Is adjusted.

Here, as a comparative example, a method for adjusting illumination light in a conventional light source device will be described.
In the conventional light source device, automatic light control is started after the rotation of the motor reaches a constant speed. In the case of performing automatic light control based on the brightness of the image of the imaging device or the display device, in order to suppress flickering of the color of the superimposed light, as shown in FIG. This is because it is necessary to synchronize and match their periods and phases.

  In order to match the cycle and phase of the imaging frame and the illumination frame, it is necessary to wait until the number of rotations of the motor becomes constant. Therefore, in the conventional light source device, as shown in FIG. 6, when the light source device is started up or restarted from reset, the light source is turned off until the rotational speed of the motor reaches the steady rotational speed. For this reason, when such a light source device is used in an endoscope system, there is a disadvantage in that the diagnosis and treatment are hindered if the extinguishing time by resetting is long.

  Further, at the time of restart, the LED 1 has been turned off until then, and automatic light control is performed based on a dark image acquired during that time. Therefore, when automatic light control is performed immediately after restarting in a conventional light source device, the LED 1 emits light at full power as shown in the region W of FIG. . As a result, there is an inconvenience that the image is overexposed and the image quality is significantly deteriorated.

  On the other hand, in the conventional light source device, when the LED is turned on immediately after restarting and automatic dimming is performed when the steady rotation speed is reached, as shown in regions X and Y of FIG. LED1 emits light at full power until, and the deviation from the required luminance becomes large. As a result, the image becomes dark (area Y), the image is overexposed (area X), and the image quality is significantly deteriorated.

  Further, in the conventional light source device, when the automatic light control is started before the rotation speed of the motor reaches the steady rotation speed, as shown in FIG. 8, the imaging frame and the illumination frame do not coincide with each other. The illumination brightness adjusted based on the brightness is switched in the middle of the illumination frame. As a result, in the case of a light source device that configures a spectrum with LEDs of a plurality of colors, the color balance in the illumination frame is lost.

  Specifically, in the example of FIG. 8, only the R and G components are illuminated in the first imaging frame, and illumination light having a high ratio of G components is irradiated in the third imaging frame. Even considering that the human eye perceives the integral value of the brightness of several frame images due to the visual afterimage phenomenon, the flickering of the color remains strong due to such fluctuations in the spectral components.

  On the other hand, in the light source device 10 according to the present embodiment, as shown in FIG. 9, dimming is performed before the rotation speed of the motor 2 reaches the steady rotation speed, that is, when the imaging frame and the illumination frame do not match. Control to fix the value. By performing such control, it is possible to fix the RGB ratio of the illumination light that irradiates the object to be illuminated in each imaging frame, and it is possible to prevent the color flickering feeling.

The operation of the light source device 10 that performs the above control will be described below.
When the light source device 10 is activated, the light guide member 11 is rotationally driven around the central axis L by the motor 2, and the LEDs 1 facing the incident surface 9 of the light guide member 11 are sequentially pulsed. Thereby, the high-intensity illumination light emitted from the LED 1 is continuously incident on the incident surface 9 of the light guide member 11, and is superimposed and emitted from the light guide 6 toward the object to be illuminated.

  The reflected light from the object to be illuminated is acquired by the imaging device 31 and sent as an image signal to the image brightness calculation unit 33 via the image processing circuit 32. In the image brightness calculation unit 33, an image luminance signal is calculated as image brightness information and is sent to the light source light quantity calculation circuit 35. In the light source light quantity calculation circuit 35, the light source light quantity instruction value, that is, the light emission of the LED 1, based on the image luminance signal output from the image brightness calculation circuit 33 and the image brightness value output from the image brightness setting means 34. The intensity is calculated, and the calculated light source light quantity instruction value is output to the write control circuit 25.

  In this case, when the rotation speed of the motor 2 has reached the steady rotation speed, the light source light quantity instruction value calculated by the light source light quantity calculation circuit 35 is written into the nonvolatile memory 24 for each frame by the write control circuit 25. . The drive signal instruction circuit 23 outputs a drive signal to the light source drive circuit 22 in accordance with the contents written in the nonvolatile memory 24, the rotation number signal from the rotation detection means 27, and the value of the pulse width / current table 28. The light source drive circuit 22 sends the drive current generated by the drive signal and the lighting timing signal to each LED 1, and sequentially turns on the LEDs 1 facing the incident surface 9 of the light guide member 11 in a pulse manner.

  On the other hand, when the motor 2 is in the middle of starting and the rotation speed of the motor 2 has not reached the steady rotation speed, writing of a new light source light amount value to the nonvolatile memory 24 by the writing control circuit 25 is prohibited. Thereby, the value immediately before starting (or restarting) is held in the nonvolatile memory 24. Then, the drive signal instruction circuit 23 generates a drive signal to the light source drive circuit 22 from the light source light quantity instruction value immediately before starting (or restarting) and the current value / pulse width corresponding to the rotation speed of the motor 2.

  Specifically, as shown in FIG. 10, when the required light amount after activation is 100% of the light amount before activation, the driving current and pulse width of the LED 1 are set so that A point → D point → E point. Is controlled. Similarly, when the required light amount after activation is 75% before activation, point A → C point → F point, and when it is 50% before activation, point A → B point → G point, light amount 25 before activation. In the case of%, the drive current and the pulse width of the LED 1 are controlled so that the point I changes from the point I to the point H.

The above operation will be described below with reference to the timing chart shown in FIG.
FIG. 11 shows an operation when the light quantity instruction value recorded in the nonvolatile memory 24 before starting is 100%.
When the light source device 10 is started from the stop state shown in the area a of FIG. 11, the rotational speed of the motor 2 gradually increases as shown in the area b of FIG. 11. At this time, if the pulse width of the LED 1 is reduced and the current value is increased, the amount of light emitted from the LED 1 increases accordingly. In this state, the motor 2 is increasing in rotation, and the LED 1 is driven with a pulse width corresponding to the rotation speed and a current value determined by the above-described characteristic L corresponding to the pulse width. In this case, the light amount of the LED 1 is 100% of the light source light amount instruction value recorded in the nonvolatile memory 24, so that the LED 1 is driven with a current value determined by the characteristic L (the state from point A to point D in FIG. 10).

  Then, as shown in a region c in FIG. 11, when the current value of the LED 1 becomes constant at the maximum value while the rotation of the motor 2 is increasing, the LED 1 is driven with a pulse width and a maximum current value corresponding to the rotational speed (FIG. 10 is a state from point D to point E).

And as shown to the area | region d of FIG. 11, when the rotation speed of the motor 2 reaches a steady rotation speed, the automatic light control according to image brightness will be performed by adjusting the pulse width of LED1.
In this state, for example, when resetting is performed due to an abnormality or the like, the rotation speed of the motor 2 gradually decreases and the current value of the LED 1 becomes zero as shown in a region e in FIG.

  Thereafter, when the light source device 10 is restarted by an abnormal reset or the like, as shown in a region f in FIG. 11, the rotational speed of the motor 2 gradually increases, and the LED 1 is driven with a pulse width corresponding to the rotational speed. . At this time, the LED 1 is driven with the current value determined by the characteristic L until the light amount when the LED 1 is driven with the current value determined by the characteristic L exceeds the light source light amount instruction value recorded in the nonvolatile memory 24.

Then, as shown in a region g in FIG. 11, the current value is such that the light amount when the LED 1 is driven with the current value determined by the above-described characteristic L according to the pulse width is equal to the light amount value recorded in the nonvolatile memory. Is adjusted to be the light source light quantity instruction value recorded in the nonvolatile memory 24. Specifically, for example, when the amount of light when the LED 1 is driven exceeds the amount of light recorded in the nonvolatile memory, the current value indicated by point B to point G in FIG. Adjust to the current value shown in.
Then, as shown in a region h in FIG. 11, when the rotational speed of the motor 2 reaches the steady rotational speed, automatic light control according to the image brightness is performed by adjusting the pulse width.

  As described above, according to the light source device 10 according to the present embodiment, the light source light quantity instruction value of the LED 1 is calculated by the light source light quantity calculation circuit 35 based on the brightness of the image calculated by the image brightness calculation unit 33. The This light source light quantity instruction value is stored in the nonvolatile memory 24 and is updated at a predetermined interval by the writing control circuit 25, and the LED 1 is caused to emit light with the updated light source light quantity instruction value. Thereby, based on the brightness of the image calculated by the image brightness calculation unit 33, it is possible to perform so-called automatic light control that adjusts the amount of superimposed light emitted from the light guide 6.

  At this time, if the rotation speed of the motor 2 does not reach the steady rotation speed, the writing control circuit 25 prohibits the update of the light source light quantity instruction value of the LED 1 to the nonvolatile memory 24 and stores it in the nonvolatile memory 24. The LED 1 is controlled to emit light at the latest light source light quantity instruction value. Thereby, for example, even when the motor 2 does not reach the steady rotational speed at the time of restart due to an abnormal reset, the latest light source light quantity instruction value stored in the nonvolatile memory 24, that is, the light source light quantity instruction before restarting. LED1 can be made to emit light by the value. By doing in this way, the change of the light quantity of the superimposition light before and after restart can be made small, and it can prevent that the light quantity of superimposition light becomes too large or too small.

  Further, when the motor 2 reaches the steady rotation speed, the automatic light control can be started by starting the update of the light emission intensity to the nonvolatile memory 24 by the write control circuit 25. Here, when the motor 2 reaches the steady rotation speed, the imaging frame and the illumination frame can be synchronized so that their periods and phases coincide with each other. By starting the automatic light control in this state, it is possible to suppress flickering of the color of the superimposed light, and it is possible to emit the superimposed light having a stable color.

  Further, by controlling the pulse width and driving current of the LED 1 according to the number of revolutions of the motor 2, the light emission intensity of the LED 1 can be easily controlled.

  Moreover, according to such an endoscope 50, since the above-described light source device 10 is provided, when the LED1 device is started up or restarted by resetting, the LED1 is not put on standby in an off state, and observation can be performed immediately. Can start. Further, at that time, it is possible to prevent the amount of superimposing light that illuminates the observation area from being excessively large or small, and to prevent the observation image from being overexposed or darkened. It can be observed with high accuracy.

As mentioned above, although embodiment of this invention was explained in full detail with reference to drawings, the specific structure is not restricted to this embodiment, The design change etc. of the range which does not deviate from the summary of this invention are included.
For example, in the present embodiment, the example in which the light source device 10 is applied to the endoscope 50 has been described. However, the light source device 10 may be applied to other devices such as a projector.
In this embodiment, the brightness of the reflected light from the object to be illuminated is detected by an imaging device such as a CCD. However, the light amount of the superimposed light itself may be detected by an optical sensor or the like.

1 LED
2 Motor 3 Rod base 4 Light guide rod 5 Reflective prism 6 Light guide 9 Incident surface 10 Light source device 11 Light guide member 20 Illumination system 21 Light source unit 22 Light source drive circuit 23 Drive signal instruction circuit 24 Non-volatile memory (storage unit)
25 Write control circuit (update means)
26 Illumination optical system 27 Rotation detection means 28 Pulse width / current table 30 Imaging system 31 Imaging device 32 Image processing circuit 33 Image brightness calculation circuit (light detection unit)
34 Image brightness setting means 35 Light source light quantity calculation circuit (emission intensity calculation unit)
50 Endoscope L Center axis

Claims (4)

A plurality of light sources arranged in a ring at a predetermined interval and arranged with the optical axis directed radially inward of the ring;
An incident surface on which illumination light emitted from the light source is incident is arranged outward in the radial direction of the ring, and the illumination light incident on the incident surface is guided in a direction along the central axis of the ring. A light guide unit to
A rotating unit that rotationally drives the light guide unit around the central axis;
A light detection unit for detecting the intensity of light guided by the light guide unit;
A light emission intensity calculation unit for calculating the light emission intensity of the light source based on the light intensity detected by the light detection unit;
A storage unit for storing the emission intensity of the light source calculated by the emission intensity calculation unit;
Updating means for updating the light emission intensity of the light source stored in the storage unit at predetermined intervals;
A control unit for controlling the light source and the updating means,
The control unit prohibits updating of the light emission intensity of the light source to the storage unit by the updating unit when the rotating unit has not reached constant speed rotation, and the latest stored in the storage unit A light source device that sequentially pulses the light source facing the incident surface with emission intensity.   When the rotation unit has reached a constant speed rotation, the control unit starts updating the light emission intensity of the light source to the storage unit by the updating unit and causes the light source to emit light with the updated light emission intensity. The light source device according to claim 1.   The light source device according to claim 1, wherein the control unit controls a pulse width and a driving current of the light source according to a rotation speed of the rotating unit. The light source device according to any one of claims 1 to 3,
An endoscope system comprising: an imaging device that captures an area illuminated by the light source device.

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