JP3043877B2 - Electronic endoscope device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electronic endoscope apparatus for capturing an image of a subject with a solid-state image sensor such as a CCD mounted on the distal end of an endoscope scope and displaying the captured image on a monitor.

[0002]

2. Description of the Related Art As is well known, an endoscope in an electronic endoscope apparatus of this kind has an electric circuit such as a CCD image pickup device in a portion inserted into a body cavity of a patient. Therefore, if a failure occurs such that the electric circuit is short-circuited or has low resistance, the portion may generate heat and harm the subject. In addition, if the electric circuit is disconnected or the resistance becomes large, the normal operation may not be performed and the image may disappear. Further, a power supply circuit for supplying power to an electric circuit of a portion to be inserted into the body cavity of the endoscope or a driver capable of sufficiently supplying current is generally provided so as to be able to supply power stably with respect to load fluctuation. However, when the above-mentioned short-circuit or low-resistance state, disconnection or high-resistance state is maintained, the state is maintained, and in the related art, a dangerous state may be created for the subject.

[0003]

However, in the case of this type of conventional electronic endoscope apparatus, the above-mentioned short-circuit or low-resistance state, disconnection or high-resistance state is completely known when operating the endoscope. However, the above-mentioned problem, that is, the following problem was found.

(1) Failure of a part inserted into a body cavity may harm a patient.

[0005] (2) Even if a failure occurs, the operator cannot detect the danger because the failure cannot be detected.

(3) Even if the operator notices the failure,
If the operator does not perform an operation such as turning off the power, the situation remains unchanged and is dangerous.

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances. It is an object of the present invention to monitor the presence or absence of an electrical failure of an endoscope and to take an immediate action when a failure occurs. An endoscope apparatus is provided.

[0008]

According to the present invention, in order to achieve the above object, an electric circuit including at least a solid-state image pickup device is provided at a distal end portion of an endoscope, and a video signal from this electric circuit is internally transmitted. In an electronic endoscope apparatus which displays an endoscope image on a display means, detection means for detecting a state of power supply to the electric circuit or signal transmission from the electric circuit by a current value, and a current detected by the detection means If the value is higher than the first current level, a warning is issued and the device is immediately turned off. If the value is lower than the first current level but higher than the second current level, a warning is issued and the device is turned off after a first time. And a control means for issuing a warning if the current level is lower than the third current level and controlling to turn off the power of the apparatus after a second time longer than the first time has elapsed. .

[0009]

In the electronic endoscope apparatus according to the present invention, the control means comprises:
If the current value detected by the detecting means is higher than the first current level, a warning is issued and the power supply of the device is immediately turned off. If the current value is lower than the first current level and higher than the second current level, a warning is issued and the first is issued. After the time elapses, the power of the device is turned off. If the current level is lower than the third current level, a warning is issued and the power of the device is turned off after the elapse of the second time longer than the first time.

[0010]

FIG. 1 is a block diagram showing the configuration of an electronic endoscope apparatus according to a first embodiment to which the present invention is applied. In this embodiment, the processor is provided with a current detection mechanism.
This may be provided on the endoscope.

The electronic endoscope apparatus according to the first embodiment is shown in FIG.
Scope end portion 1 of endoscope 100 as shown in FIG.
In FIG. 1, a CCD module 2 includes a CCD image sensor 1 and a buffer amplifier 3 for a signal (OS signal) from the CCD image sensor 1 in the relationship shown in FIG. Such a scope distal end 100a is inserted into a body cavity of a patient. For this reason, if any failure occurs in the CCD module 2 and the electric circuit inside the scope is short-circuited or short-circuited due to low resistance, and there is a danger that the patient may be burned if an abnormal overcurrent flows and generates heat. .

The CCD module 2 has a power supply,
Power is supplied from the DC power supply 4 for DC bias of the CD, bias for the buffer amplifier 3, and the like. At the same time, the CCD image sensor 1 is supplied with a vertical clock 5 and a horizontal clock 6 for scanning pixels. These are signals that may cause an overcurrent to flow due to a short circuit or the like. Furthermore, since the video output signal (OS signal) 7 from the CCD module 2 is supplied from the buffer amplifier 3, if a short circuit occurs in the CCD module 2, the bias current of the buffer amplifier 3 becomes an overcurrent.

Therefore, in this embodiment, the DC power supply 4 for supplying power to the CCD module 2 and the vertical clock 5 for supplying the CCD module 2 are produced by the processor 28 of the apparatus main body (not shown), and the horizontal clock 6 is internally generated. The horizontal clock driver 29 in the endoscope 100 creates
A plurality of power supply currents 8 supplied to the endoscope 100
And the vertical clock driver 16 inside the processor 28
Supply currents 9 to the current sensor circuits 10 and 13
Monitoring using the endoscope 100
The detection of the overcurrent generated in the above is performed. Although only one power supply current 8 and one supply current 9 are shown in FIG. 1, there is actually only a necessary power supply. For example, the power supply to the vertical clock driver 16 is +15
V, + 5V, -7, + to the endoscope 100
There are two types, 15V and + 9V.

The operation of the DC power supply applied to the CCD image pickup device 1 is as follows.

The current from the power supply 17 is supplied to the current sensor circuit 1
0, the current is supplied to the scope through the current limiter circuit 11 and the current cutoff circuit 12. Although only one set of these is shown in FIG. 1, when there are a plurality of DC voltages, they are provided for each of them.

The power supply of the CCD image pickup device 1 is +15 V, and usually flows only about 15 mA. Therefore, the current sensor circuit 10 outputs an overcurrent signal 10a when a current of 23 mA or more increases by 50% in consideration of component variation, noise, and the like.
Is output. When the signal 10a is detected by the controller 21, the controller 21 writes a warning indicating that the overcurrent is flowing to the graphic memory 23. The output of the graphic memory 23 is added to the video signal by the addition circuit 25, and a warning is displayed on the display device 24. On the other hand, the overcurrent signal is output to the video signal processing circuit 22.
It is connected to. When there is an overcurrent signal, the video signal processing circuit 22 changes its built-in color processing circuit to change the color of the image on the display device 24 so that the image looks apparently abnormal. Thus, even if the controller 21 or the graphic memory 23 is abnormal, an operator can know that an abnormality has occurred.

On the other hand, when an overcurrent is detected, the timer 19 operates. This is provided so that even if an overcurrent is generated due to an abnormality of the CCD module 2 but an image is displayed, the image continues to be output even a little. In endoscopy, it is dangerous if images can be obtained immediately because surgery is performed. Therefore, if an image appears, it is desirable to continue to output the image even a little. Normally, the timer 19 is set to 30 seconds because it is said that the human body can be removed from the body in about 30 seconds. While the timer 19 is operating, a warning is displayed on the display image, and the color is changed so that the color is apparently abnormal. First, an operation of removing the endoscope 100 from the body is performed.

When the set time of the timer 19 comes, the timer 19 activates the current cutoff circuit 12 to cut off all power to the CCD module 2. Thus, even if the operator does not perform the operation of removing the endoscope 100, the user can escape from a situation that may endanger the patient.

In the above case, the temperature rise at the distal end of the scope was gradual, and an image continued to appear due to a short circuit having a low resistance instead of a module short circuit. However, a short circuit with almost no resistance can be considered. In this case, when a short circuit occurs at the distal end of the scope, the temperature at the distal end of the scope rapidly rises. In this example, the current limiter 11 is used as a countermeasure. The current limiter 11 does not perform any function up to a certain current, but if a current higher than a preset current flows, the voltage is reduced and only the set current flows. If the temperature is about 100 mA experimentally from the state of heat generation at the tip of the scope, a dangerous temperature will not be reached in 30 seconds, so in this example, 100 mA is set as the limiter setting value. Even if the load is short-circuited and the resistance is reduced, no more than 100 mA will flow. Also at this time, since the current sensor circuit 10 has detected an overcurrent, a warning is displayed as described above.
All power is turned off in 30 seconds.

As described above, the DC power applied to the CCD image pickup device 1 is monitored, and when an abnormality is detected, the power is shut off. This also applies to vertical and horizontal clocks. But for the clock,
The energy that causes heat generation is an average over time. Since this is just the power supply current supplied to the clock driver, in this embodiment, similar to the case of the DC power supply described above, the vertical clock driver 1
6 is monitored by the current sensor circuit 13, the controller 21 detects the occurrence of the overcurrent signal 13 a in the current sensor circuit 13, and issues a warning indicating that the overcurrent has flowed to the graphic memory 23. A warning is displayed on the writing and display device 24.
The timer 20 is activated by the detection of the overcurrent, and after a lapse of a predetermined time, the signal cutoff circuit 15 is activated to stop the supply of the vertical clock signal to the CCD module 2 or to suppress the signal supply by the current limiter circuit 14. I have. Note that the horizontal clock is set in accordance with the cutoff of the DC power supply.

Next, the interruption when the illumination system is abnormal will be described.

In the endoscope, the inside of the body must be illuminated. Generally, light from a powerful lamp 102 inside the processor is guided to the tip by a light guide 101 made of an optical fiber for illumination. Light guide 101 from lamp 102
In the meantime, it is possible to change the intensity of the lighting by making an aperture or the like. In normal operation, CCD1
The intensity of the illumination is changed so that the luminance of the video signal output from the LCD falls within a certain range. The mechanism is ALC (auto
matic lighit contrller) 26. The problem here is that the lighting is so powerful that heat is generated.
The distal end of the scope is illuminated from the light guide 101 through an illuminating lens (not shown), but it is difficult to reduce light loss between glass and air due to size restrictions. Therefore, when the lighting is performed, the loss is converted to heat.

In normal observation, it is rare that the amount of light becomes maximum, so that heat generation is not so great as to cause a problem. But CCD
If the module 2 fails and no image appears, ALC2
In the case of No. 6, since the light amount is maximized, a dangerous state is generated due to heat generation at the distal end of the scope.

As a countermeasure, in this embodiment, the controller 2
When 1 detects an abnormality, a command is sent to the lamp controller 27 after a certain period of time has elapsed, and the lamp 102 is turned off. This time is set to be slightly longer than the time during which the power is cut off due to the overcurrent, so that the image is continuously output as long as the image is output.

Next, embodiments of an overcurrent detecting circuit composed of a combination of a current sensor circuit, a timer and a current limiter will be described.

FIG. 3 is a circuit diagram showing a configuration of the first embodiment of the overcurrent detection cutoff circuit. The operation is described below.

The overcurrent is detected by a resistor 201 and a transistor 202. As the current flowing to the load increases, the voltage drop across the resistor 201 increases. When this voltage exceeds the emitter-base voltage (VBE) of transistor 202, transistor 202 turns on. As a result, the transistor 203 is turned on, so that the output of the gate 204 becomes H
Becomes For example, if a silicon transistor is used as the transistor 202, VBE is about 0.6 V, so that the resistance 201 may be set to 24Ω to make the detection current 25 mA.

The current limiter is composed of a transistor 205 and a transistor 206.
06 and the transistor 209. At a current smaller than the limit value, the voltage drop of the resistor 210 does not turn on the transistor 205 and the transistor 205 has no relation to the operation. At that time, when the output of the gate 208 becomes H, the transistor 209 is turned on, the base current of the transistor 206 flows, and the transistor 206 is turned on. Gate 20
When the output of 8 becomes L, the base current stops flowing, so that the transistor 206 is turned off and the current can be cut off.

When a current flows while the transistor 209 is in the ON state, the voltage drop of the resistor 210 increases as the current increases, and when the current reaches the VBE of the transistor 205, the collector current of the transistor 205 starts flowing.
Then, the voltage drop of the resistor 211 increases, and the base current of the transistor 206 decreases. The reduction of the base current of the transistor 206 limits the current to the load, and acts as a current limiter. Limit current about 100mA
The resistance 210 may be set to 6Ω so that the voltage drop of the resistance 210 becomes 0.6V.

These are affected by temperature changes because the VBE of the transistor is used. However, since the values of both the overcurrent detection and the current limit have a margin, no problematic error occurs in the operating temperature range.

FIG. 4 is a circuit diagram showing a configuration of a second embodiment of the overcurrent detection cutoff circuit. This allows the CPU to vary the set voltage. As an operation, when the CPU writes voltage data to be set in the register 301 through the data bus, the D / A converter 302 outputs a voltage corresponding to the data. This voltage is amplified by the DC amplifier and output. An operational amplifier 303 includes transistors 304 and 3
05 together with a DC amplifier. Load current flows from the power supply through the path of the resistor 306, the resistor 307, and the transistor 308. As in the first embodiment, the detection of the overcurrent is performed by the resistor 306 and the transistor 309.

Here, the capacitor 310 forms a time constant with the resistor 311. Usually, a load includes a capacitor for noise suppression. Therefore, at the moment when the set voltage is increased, a current required for charging the capacitor flows. This current is instantaneous and has nothing to do with heat generation, but is detected by the overcurrent detection circuit. Therefore, the capacitor 31
0, the output is output only when the overcurrent continues for a certain period of time or more with the time constant of the resistor 311. In this example, the time is determined by a capacitor and a resistor. However, the accuracy is improved by using a digital circuit such as counting a fixed clock by a counter.

In FIG. 3, the current is cut off by setting the output voltage to 0V. Although the CPU may set 0 V, it is desirable that the voltage can be set to 0 V by hardware in order to increase reliability.
In this example, a reset (clear) signal of the register 301 is used. When this signal becomes L, the outputs of the registers all become L, and the D / A converter 302 outputs 0V. This interrupts the current.

In each of the above-described embodiments of the present invention, only overcurrent can be detected. However, when the current value is smaller than the specified value, a failure such as disconnection can be considered. In this case, the possibility of causing harm due to heat generation or the like is smaller than the overcurrent, but it is still a failure, and abnormality detection is important.

Therefore, in the electronic endoscope apparatus according to the second embodiment of the present invention, as shown in FIG. 5, a current sensor 401 for detecting a current by the amount of magnetism generated around the electric wire is used as the current sensor. . The output of the current sensor 401 is amplified by the amplifier 402, digitized by the A / D converter 403, and transmitted to the CPU.

The CPU performs the processing as shown in FIG.
This processing is always performed at regular intervals using, for example, a timer interrupt, so that any abnormality can be dealt with.

First, a current sensor is read in step ST1. Next, in step ST2, it is determined whether or not this value is within a normal range. If it is between IMIN and IMAX1, it is normal and exits without doing anything. If the current is too large or too small, the process branches here and waits for T1 in the timer processing of step ST3, and then reads the current sensor again in step ST4. This timer processing eliminates any transient overcurrent such as inrush current, and waits for a time of, for example, several tens of milliseconds.

The value read from the current sensor again is IMAX
If it is larger than 2, the flow branches at step ST5. This value is a value at which the current should be immediately interrupted due to a short circuit or the like. For example, about 200 mA. If the current is higher than this, it is displayed in step ST8, and the output is immediately cut off in step ST13. At the same time, the illumination lamp is turned off in step ST14. In the endoscope apparatus of the first embodiment shown in FIG. 1, only this is performed. However, it is dangerous even if the operator gets upset and keeps supplying air, so that the next step S
At T15, the air supply pump is also turned off.

Even if the current value does not exceed IMAX2, I
If it exceeds MAX1, the process branches at step ST6. Although this value is abnormal, it does not cause dangerous heat generation immediately, and it is desirable to keep outputting an image for a little longer because an image is generated. Therefore, at the same time as the warning display in step ST9, the timer processing in step ST10 waits for the time T2. For example, this IMAX1 can be 25 mA, and T2 can be 30 seconds. Note that the warning display in step ST9 indicates that the image can be obtained in 30 seconds, so that the patient is immediately removed from the body. After T2, the output is similarly turned off (step ST13), the lamp is turned off (step ST14),
The pump is stopped (step ST15).

Next, when the current is smaller than IMIN, the process branches at step ST7. In this case, it is not immediately dangerous but it is a failure. Therefore, step ST
A warning is issued at 11, and only T3 is waited. This time may be longer than T2, but if it is too long, there is a possibility that the failure will be enlarged. Also in this case, the output is cut off in the same manner as in the above two examples.

When the above three abnormalities are detected, step ST16 is performed. This is used to indicate that an abnormality has occurred in the past when the scope is connected to the processor by writing the current abnormality into the history management memory of the scope, indicating that the scope cannot be used. This memory uses a nonvolatile memory such as an EEPROM. The memory may be inside the processor, but it can also be used as data for repairs by having the memory inside the scope.

[0042]

As described above, according to the present invention,
The monitoring mechanism can detect a failure of an electric circuit inside the endoscope scope, notify the operator of the failure, and enable a processing operation to automatically secure the operation. Along with this, the reliability of the electronic endoscope apparatus is greatly improved as compared with the related art.

[Brief description of the drawings]

FIG. 1 is a block diagram illustrating a configuration of an electronic endoscope apparatus according to a first embodiment to which the present invention has been applied.

FIG. 2 is a perspective view showing an appearance of an endoscope.

FIG. 3 is a circuit diagram showing a configuration of a first embodiment of an overcurrent detection circuit.

FIG. 4 is a circuit diagram showing a configuration of a second embodiment of the overcurrent detection circuit.

FIG. 5 is a circuit diagram showing a main part of a monitoring mechanism in an electronic endoscope apparatus according to a second embodiment to which the present invention is applied.

FIG. 6 is a flowchart illustrating a processing operation of a monitoring mechanism in the electronic endoscope apparatus according to the second embodiment of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 CCD imaging device 2 CCD module 3 Buffer amplifier 4 DC power supply 5 Vertical clock 7 Video output signal 8 Power supply current supplied to an endoscope scope 9 Current supplied to a vertical clock driver 10 Current sensor circuit 11 Current limiter circuit 12 Current cutoff circuit DESCRIPTION OF SYMBOLS 13 Current sensor circuit 14 Current limiter circuit 15 Signal cutoff circuit 16 Vertical clock driver 17 Power supply 18 Timing generator 19 Timer 20 Timer 21 Controller 22 Video signal processing circuit 23 Graphic memory 24 Display device 25 Addition circuit 26 ALC 27 Lamp controller 28 Processor 29 Horizontal Clock driver 100 Endoscope scope 101 Light guide 102 Lamp

Claims (3)

(57) [Claims] 1. An electronic endoscope apparatus comprising: an electric circuit including at least a solid-state imaging device installed at a distal end portion of an endoscope scope; and a video signal from the electric circuit displayed on a display unit as an endoscope image. Detecting means for detecting the state of power supply to the electric circuit or signal transmission from the electric circuit by a current value; and issuing a warning if the current value detected by the detecting means is higher than a first current level. Powering down the device, issuing a warning if lower than the first current level and higher than the second current level, and powering down the device after a first period of time; issuing a warning if lower than the third current level; Control means for controlling the power supply of the device to be turned off after a lapse of a second time longer than the first time. 2. The electronic endoscope apparatus according to claim 1, wherein the warning is issued by changing a color of the endoscope image. 3. The electronic endoscope apparatus according to claim 1, further comprising a storage unit configured to store that an abnormality that causes the warning is detected.