JP2710364B2 - Light source device for endoscope - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to an endoscope light source device that has an aperture and a shutter function and supplies illumination light to an endoscope to which an endoscope camera can be attached. About.

[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 internal body cavities and the like and performing various treatments using a treatment tool inserted into a treatment tool channel as necessary are widely used.

An endoscope light source that supplies illumination light to the endoscope is conventionally, for example, as shown in JP-A-61-13236,
Although it has an aperture mechanism for automatic light control and a shutter function for photographing, both are mechanical, and have a problem that the structure is complicated and expensive.

In addition, because of its high brightness, it is not possible to use the high-speed shutter generally used in 35 mm cameras, etc., from the viewpoint of heat resistance.For example, the conventional method of driving a plate with a solenoid to insert and remove it into the optical path However, there is a problem that a high-precision photograph cannot be obtained due to the delay time of the shutter operation.

In addition, as shown in FIG.
The conventional aperture mechanism that adjusts the amount of light by shielding a predetermined amount of light has a problem that the light distribution characteristics change with the aperture value.

The present invention has been made in view of the above circumstances, and has as its object to provide an endoscope light source device having a diaphragm and a shutter function with a simple structure.

[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 that supplies illumination light to an endoscope to which an endoscope camera can be attached, comprising: A light source capable of emitting light; light source control means capable of controlling the light emission duty of the light source, and prohibiting light emission of the light source for a predetermined period when synchronizing with a synchro signal from the endoscope camera and detecting an exposure completion signal. It is characterized by having.

[Operation] In the present invention, the aperture function is achieved by changing the light emission duty of the light source capable of multi-strobe light emission.
Further, the shutter function is achieved by inhibiting light emission of the light source for a predetermined period in synchronization with a synchronization signal from the endoscope camera.

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

FIGS. 1 to 6 relate to an embodiment of the present invention.
FIG. 2 is an explanatory diagram showing the configuration of the endoscope apparatus, FIG. 2 is a circuit diagram showing a photometric circuit, FIG. 3 is a block diagram showing a control circuit, and FIG. 4 is a timing chart for explaining the operation of the present embodiment. FIG. 5 is a waveform chart for explaining the automatic light control operation, and FIG. 6 is a waveform chart showing an example of the automatic light control operation.

As shown in FIG. 1, the endoscope apparatus includes an endoscope 1 and a photographing camera (hereinafter, referred to as a camera) 15 which is detachably attached to an eyepiece 8 of the endoscope 1. Have. The endoscope 1 has an elongated, for example, flexible insertion section 2 inserted into the body cavity 20 or the like, and a large-diameter operation section 3 is connected to the rear end of the insertion section 2. . A flexible universal cord 4 extends laterally from the operation unit 3, and a connector connected to the light source device 6 is provided at an end of the universal cord 4. An eyepiece 8 is provided at the rear end of the operation unit 3.

An illumination window and an observation window are provided at the distal end 9 of the insertion section 2. A light distribution lens 10 is mounted inside the illumination window, and a light guide 11 is connected to the rear end of the light distribution lens 10. The light guide 11 is inserted through the insertion section 2, the operation section 3, and the universal cord 4, and is connected to a connector. When this connector is connected to the light source device 6, the illumination light from the light source device 6 is guided to the distal end portion 9 via the light guide 11, and illuminates the subject through the light distribution lens 10. ing.

An objective lens 12 is provided inside the observation window. At the image forming position of the objective lens 12, a distal end surface of an image guide 13 made of a fiber bundle is arranged. The image guide 13 is inserted through the insertion section 2 and extends to the eyepiece 8, and the rear end face faces the eyepiece 14 in the eyepiece 8. And the objective lens
The subject image formed by 12 is guided to the eyepiece 8 by the image guide 13, and is observed from the eyepiece 8.

The camera 15 connected to the eyepiece 8 is
A half mirror 21 for separating the light from the camera into two light beams, and one of the light beams transmitted through the half mirror 21 is reflected by a rotatable mirror 22 and then passed through a pentaprism 23 to a camera eyepiece. Eyepiece 24. Then, an endoscope image can be confirmed through the eyepiece lens 24. When taking a picture, the mirror 22 is rotated to the position indicated by the broken line, and the one light beam is applied to the film 25.

The other light beam reflected by the half mirror 21 is
The light is received by the light receiving element 27 in 15. The light receiving element 27 is connected to a photometric circuit 28,
Are connected to the control circuit 29. The control circuit 29 includes a film winding circuit 3 for controlling winding of the film 25.
1. A mirror drive circuit 32 for controlling the mirror 22, a release switch 33, and an EE line 35 are connected. The EE line 35 is introduced into the light source device 6 through a contact provided between the camera 15 and the eyepiece 8 of the endoscope 1 and a signal line inserted into the endoscope 1. Has become.

In the camera 15 having such a configuration, when the release button 33 is pressed, as shown in FIG. 4A, an EE signal, a synchro signal, an integration start signal, an exposure completion signal, An imaging sequence end signal is output. The superposition of these signals on the EE signal is performed by the control circuit 29. As described above, various signals are superimposed on one signal line. This is because it is desired to reduce the number of signal lines as much as possible.

The operation of the mirror 22, the operation of winding the film 25, and the operation of the photometric circuit 28 are respectively shown in FIGS.
As shown in FIG.

That is, when the release button 33 is pressed, FIG.
As shown in FIG. 4, a sync signal is output from the control circuit 29, and in synchronization with this sync signal, the mirror 22 is rotated and reflected by the mirror 22 as shown in FIG. Is incident on the film 25.
During the period (a ₁ ) shown in FIG. 4D until the synchro signal is output, the photometric circuit 28 operates in the amplification mode, and the output proportional to the amount of light incident on the light receiving element 27 is output. The voltage is output on the EE line 35.

Next, during a period (a ₂ ) shown in FIG. 4D from the output of the integration start signal from the control circuit 29 to the output of the exposure completion signal, the photometric circuit 28 operates in the integration mode. .

After the exposure completion signal is output, as shown in FIG. 4 (b), the mirror 22 rotates to the solid line position, and the light reaches the camera eyepiece. As shown in ()), the film 25 is wound up. Then, as shown in FIG. 4A, an imaging sequence end signal is output from the control circuit 29, and the imaging operation ends.

A general example of the photometric circuit 28 is shown in FIG. The photometric circuit 28 has an operational amplifier 36, and the operational amplifier 36
Are connected via a switch 37 via one of a capacitor 38 and a resistor 39. The inverting input terminal and the non-inverting input terminal of the operational amplifier 36 are connected via a diode 40, and the output of the light receiving element 27 is input to the inverting input terminal. In such a photometric circuit 28, when the switch 37 selects the capacitor 38 side, the integration mode is set, and when the resistor 39 is selected, the amplification mode is set.

 Next, the light source device 6 will be described.

The light source device 6 has a lamp 41 capable of emitting multi-strobe light.
The light enters the entrance end of the light guide 11 of the endoscope 1 via 2 and 43.

Further, the light source device 6 is provided with a lamp control circuit 45 for controlling the light emitting state of the lamp 41 and a control circuit 46 to which the EE line 35 from the camera 15 is connected and controls the lamp control circuit 45. Have been.

 The detailed configuration of the control circuit 46 is shown in FIG.

The control circuit 46 includes a sawtooth wave generation circuit 50 and a camera.
An EE line 35 is connected to the synchronizing signal detection circuit 51, an integration start signal detection circuit 52, an exposure completion signal detection circuit 53, and a synchro signal, an integration start signal, an exposure completion signal, and an imaging sequence end signal. An imaging sequence end signal detection circuit 54 is provided.

The sawtooth wave generating circuit 50 generates a sawtooth wave as shown in FIG. The frequency of the sawtooth wave is preferably about 200 Hz or more in consideration of the flicker of light. An output terminal of the sawtooth wave generation circuit 50 and an EE line
35 is connected to each input terminal of the comparator 55. Thus, the first pulse generation circuit is formed by inputting the output of the sawtooth wave generation circuit 50 and the EE signal to the comparator 55. FIGS. 5B and 5C show the output of the comparator 55 when the EE signal is small and when the EE signal is large, respectively. As described above, the smaller the EE signal is, the larger the duty ratio of the output pulse of the comparator 55 is.

The output terminals of the synchro signal detection circuit 51 and the integration start signal detection circuit 52 are connected to the set and reset terminals of a flip-flop (hereinafter referred to as FF) 56, and the exposure completion signal detection circuit 53 Each output terminal of the sequence end signal detection circuit 54 is connected to the set and reset terminals of the FF57. The output terminal of each of the FFs 56 and 57 is connected to an OR circuit 5
8 are connected to each input terminal. Outputs of the FF56, FF57 and OR circuit 58 are respectively shown in FIGS.
(G).

The output of the OR circuit 58 is input to a prohibition circuit 59. The output of the inhibition circuit 59 is output from the OR circuit 58.
Is forcibly kept at the low level during the period when the output is at the high level.

Further, there is provided a second pulse generation circuit 61 for generating a square wave having substantially the same frequency as the sawtooth wave generated by the sawtooth wave generation circuit 50. The output of the second pulse generation circuit 61 and the first pulse Comparator 55 forming pulse generation circuit
Is input to the switching circuit 60. The switching circuit 60 is controlled by the output of the integration start signal detection circuit 52 and the output of the exposure completion signal detection circuit 53, and generates the second pulse only during the period (a ₂ ) in FIG. The signal of the circuit 61 passes through the switching circuit 60, and the inhibit circuit 59
During the period other than (a ₂ ) in FIG. 4D, the output of the comparator 55 passes through the switching circuit 60 and the inhibit circuit 59
To be entered.

To summarize the operation of the control circuit 46 having such a configuration, during the period (a ₁ ) of FIG. 4D, a pulse having a duty corresponding to the brightness of the EE signal is output from the inhibition circuit 59, ₂ )
In the period, the pulse output from the second pulse generation circuit 61 is output to the inhibition circuit 59. Further, during the periods (b ₁ ) and (b ₂ ), no pulse is output from the inhibition circuit 59.

The output of the prohibition circuit 59 is output to the lamp control circuit 45.
Is input to

On the other hand, the lamp control circuit 45 outputs the output of the control circuit 46,
That is, the lamp 41 is turned on only during the period when the output of the inhibition circuit 59 is at the high level.

Therefore, the operation of the lamp 41 is as shown in FIG.

That is, during normal observation, multi-flash emission is performed at a light emission duty corresponding to the brightness of the EE signal. As a result, an aperture function is achieved, and automatic light control is performed. For example, as shown in FIG. 6 (a), when the subject is close and bright, the light emission duty becomes small, and as shown in FIG. 6 (b), when the subject is far and dark, the light emission duty becomes large.

On the other hand, during photography, light emission is prohibited during the period (b ₁ ) from the camera 15 to the synchro signal to the integration start signal.
Thus, the film 25 of the camera 15 is not exposed.

Further, during a period (a ₂ ) from the integration start signal to the exposure completion signal, multi-flash emission is performed at a predetermined frequency and duty by the pulse output from the second pulse generation circuit 61.

Then, during the period (b ₂ ) from the completion of the exposure to the end of the photographing sequence, light emission is prohibited. Thereby, a shutter function is achieved.

As described above, according to the present embodiment, the light emission duty of the lamp 41 is changed according to the brightness.
This eliminates the need for a mechanical diaphragm, which was conventionally required.
Further, for example, in the conventional aperture stop as shown in FIG. 11, there is a problem that the light distribution characteristic is changed according to the aperture amount, but according to the present embodiment, the light emission of the lamp 41 is controlled. This solves the problem of light distribution.

Further, according to the present embodiment, the light emission of the lamp 41 can be prohibited for a predetermined period, so that a mechanical shutter which has been required conventionally becomes unnecessary.

The light emitted from the endoscope light source is guided by the light guide 11 of the endoscope 1 to the distal end 9 of the insertion section 2 to illuminate the inside of the body cavity 20 and the like. , The amount of light emitted from the light source is very large. Therefore, high-speed shutters usually used in cameras cannot be used due to heat resistance.For example, in a conventional shutter in which a plate is driven by a solenoid and inserted into and removed from an optical path,
The delay time of the operation of the shutter deteriorates the photographic accuracy.
According to this embodiment, since the light emission of the lamp 41 is purely controlled, this problem is also solved.

Further, conventional diaphragms and shutters have a problem that they are complicated, expensive, and are liable to break down due to mechanical movement. However, according to the present embodiment, a simple diaphragm without a mechanical diaphragm and shutter is used. The structure can have an aperture and shutter function.

In this embodiment, the light source device 6 is used in combination with the camera 15.
Has been described, it goes without saying that the light receiving element and the photometric circuit can be built in the endoscope to perform automatic dimming.

The light source device for an endoscope of the present invention can also be applied to a light source device for a field sequential electronic endoscope.

FIG. 7 shows an electronic endoscope apparatus to which the present invention is applied.
FIG. 10 shows a conventional electronic endoscope device.

 First, the conventional example shown in FIG. 10 will be described.

This electronic endoscope device includes an electronic endoscope 72 and a control device 73.
And a monitor 83. The control device 73 includes:
Having, for example, 74 controlled by a lamp control device 75,
The light emitted from the lamp 74 is incident on the incident end of the light guide 80 of the electronic endoscope 72 via the condenser lenses 76 and 77, the stop 78 and the rotating filter 83.

An output from a solid-state imaging device (not shown) in the electronic endoscope 72 is input to a video processing circuit 81 in the control device 73,
The video signal is converted into a television signal, input to the monitor 83, and an endoscopic image is displayed on the monitor 83.

On the other hand, from the video processing circuit 81, an aperture control signal
It is input to the aperture control device 79, and the aperture control device 79 controls the aperture 78 according to the brightness.

Further, from the video processing circuit 81, a synchronization signal is input to a motor 82 for driving a rotation filter 83, and the rotation filter
83 rotates in synchronization with the video processing circuit 81.

Next, an electronic endoscope apparatus to which the present invention is applied will be described with reference to FIG.

The same members as those in the conventional example in FIG. 10 are denoted by the same reference numerals, and only the portions different from the conventional example will be described.

In this example, there is no aperture 78 and aperture control device 79, and instead, a control circuit 84 for controlling the lamp control circuit 75 is provided.

From the video processing circuit 81, the EE signal and the synchronization signal relating to the brightness are input to the control circuit 84, and the control circuit 84 outputs pulses as shown in FIG. 9 (b).

By the way, as shown in FIG.
Filters 83R, 83G, and 83B that transmit light in red (R), green (G), and blue (B) wavelength regions, respectively, are arranged along the circumferential direction. A light shielding portion 84 is provided between the filters 83R, 83G, 83B. This rotary filter 83 rotates in the direction of the arrow in the figure.

FIG. 9A shows the position of the rotary filter 83 on the illumination optical path.
This shows that the filters G and B are sequentially interposed in the illumination light path.

The control circuit 84 generates a pulse as shown in FIG. 9 (b) only in the period shown in FIG. 9 (a) by the EE signal and the synchronization signal. The duty of this pulse is
It depends on the EE signal level.
Duty increases.

Then, the lamp control circuit 75 turns on the lamp 74 only during the high level period of the pulse shown in FIG. 9B.

As described above, by varying the duty of the pulse shown in FIG. 9B, the same function as that of the conventional diaphragm can be achieved.

Further, by changing the period shown in FIG. 9A, it is possible to adjust the white balance and change the color balance without changing the aperture ratio of the rotary filter.

It should be noted that the present invention is not limited to the above-described embodiment.
The light emission duty is not limited to the one that changes the light emission duty in accordance with the signal level to perform automatic light control, but may be one that changes the light emission duty manually.

[Effects of the Invention] As described above, according to the present invention, by changing the light emission duty of a light source capable of multi-strobe light emission,
The aperture function is achieved, and the light emission of the light source is inhibited for a predetermined period in synchronism with the synchronization signal from the endoscope camera, so that the shutter function is achieved. With such a simple structure, the aperture and shutter functions can be achieved.

[Brief description of the drawings]

1 to 6 relate to an embodiment of the present invention, FIG. 1 is an explanatory diagram showing the configuration of an endoscope device, FIG. 2 is a circuit diagram showing a photometric circuit, and FIG. 3 is a control circuit. Block diagram, fourth
FIG. 5 is a timing chart for explaining the operation of this embodiment, FIG. 5 is a waveform chart for explaining the operation of automatic light control,
FIG. 6 is a waveform diagram showing an example of an automatic dimming operation, FIG. 7 is an explanatory diagram showing an electronic endoscope apparatus to which the present invention is applied, FIG. 8 is an explanatory diagram showing a rotary filter, and FIG. FIG. 7 is a waveform diagram for explaining the operation of the control circuit in the device of FIG.
FIG. 10 is an explanatory view showing a conventional electronic endoscope apparatus, and FIG. 11 is an explanatory view showing a conventional stop. DESCRIPTION OF SYMBOLS 1 ... Endoscope, 6 ... Light source device 15 ... Photographing camera, 29 ... Control circuit 35 ... EE line, 41 ... Lamp 45 ... Lamp control circuit, 46 ... Control circuit 59 ... Prohibited circuit

Claims (1)

(57) [Claims] 1. An endoscope light source device for supplying illumination light to an endoscope to which an endoscope camera can be attached, wherein a light source capable of emitting multi-strobe light and a light emission duty of the light source can be controlled. Light source control means for inhibiting light emission of the light source for a predetermined period when synchronizing with a synchro signal from the endoscope camera and detecting an exposure completion signal. apparatus.