JPH07194531A - Electronic endoscope system - Google Patents

Abstract

PURPOSE:To protect a solid-state image pick-up device from heat by detecting temperature rises in the vicinity of the solid-state image sensing device from overcurrent generated, and controlling a drive signal that is supplied to at least either the solid-state image pick-up device or a waveform shaping means. CONSTITUTION:A scope 101 has a power control means 123 for controlling driving voltages supplied to a solid-state image pick-up device 111 and to a waveform shaping means 113 and a power control means 125 for controlling the level of driving current supplied to the solid-state image pick-up device 111, both of the means 123, 125 being operated in accordance with detection signals of a temperature detection means 127 provided in the vicinity of the solid-state image pick-up device 111 located inside the scope 101, to lower at least either the driving current level or the driving voltage or to interrupt at least either of them. The temperature detection means 127 has at least one heat sensing element such as a thermistor and detects rises in ambient temperature from changes in resistance of the heat sensing element. The powder control means 123 and 125 control the driving current level and the driving voltage, respectively, in response to changes in resistance of the thermistor.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an endoscope apparatus for observing a portion that cannot be directly viewed with the naked eye, such as a body cavity and an engine cylinder, and more particularly to a solid-state image pickup device mounted on an endoscope. The present invention relates to an electronic endoscope device capable of imaging and observing.

[0002]

2. Description of the Related Art In recent years, an electronic endoscope apparatus as shown in FIG. 8 has been known as a means for observing and imaging a portion that cannot be directly observed with the naked eye, such as a body cavity and an engine cylinder. As shown in FIG. 8, the electronic endoscope device 8
00 has a scope 101, a light source 103, and an endoscope signal processing device 105, and the light emitted from the light source 103 is
The object to be observed 109 is led out to the outside through a light guide 107 of an optical fiber bundle provided along the scope 101.
Illuminate.

An object to be observed 109 is imaged by a solid-state image sensor 111 which constitutes the scope 101, and the solid-state image sensor 1
The image signal 11 is subjected to waveform shaping and amplification for transmitting a faithful waveform by the waveform shaping means 113, and then the image signal processing circuit 115 constituting the endoscope signal processing device 105.
Entered in. The endoscope signal processing device 105 further includes a drive circuit 117 that drives the solid-state image sensor 111 and the waveform shaping unit 113 and also drives the solid-state image sensor 111, and the image signal processing circuit 115 and the drive circuit 11 are included.
Reference numeral 7 denotes a central processing unit (hereinafter referred to as CPU) 1
It is controlled by 19.

The image signal from the solid-state image sensor 111 input to the image signal processing circuit 115 is converted into a predetermined video signal and then input to an external monitor 121 and an external storage device (not shown). It The image signal processing circuit 115 controls the light source 103 so that the input image signal has a required brightness.

[0005]

The electronic endoscope apparatus described above is used in various environments, and therefore, required safety must be ensured in these environments. For example, when trying to observe the inside of a body cavity, the scope comes into contact with the liquid, so that a short circuit accident or the like must be taken into consideration. Moreover, since a high voltage may be used, an accidental short circuit may occur.

When a short-circuit accident occurs, not only the short-circuited portion is destroyed but also heat is generated due to an overcurrent resulting from the short-circuiting, so that the solid-state image sensor or the like may be thermally destroyed. In particular, if an expensive solid-state image sensor is destroyed, a considerable amount of cost is required for repair. Further, since the tip of the scope on which the solid-state imaging device is mounted has a complicated structure, it takes a considerable time to repair this portion.

Therefore, the present invention has been made in view of the above circumstances, and an object thereof is to provide an electronic endoscope apparatus capable of protecting a solid-state image pickup element constituting the electronic endoscope apparatus from heat. To do.

[0008]

In the electronic endoscope apparatus according to the present invention, an object to be observed is imaged by a solid-state image pickup device provided at the tip of a scope, and a signal photoelectrically converted by the solid-state image pickup device is waveform-shaped. In the electronic endoscope apparatus for observing the observation object, the solid-state imaging is performed by performing a required waveform shaping by a means and then guiding the signal to a signal processing apparatus provided outside the scope to perform a required signal processing. A temperature detecting means arranged in the vicinity of the element, and a power control means provided in at least one of the scope and the signal processing device and controlling a drive signal supplied to at least one of the solid-state image pickup element and the waveform shaping means. And a temperature increase in the vicinity of the solid-state image sensor due to the occurrence of overcurrent is detected by the temperature detection means, the power control means is operated to Body is obtained so as to control the driving signal supplied to at least one of the image pickup device and said waveform shaping means.

[0009]

According to the above-mentioned means according to the present invention, when an overcurrent is generated in the electronic endoscope apparatus and the solid-state image pickup device arranged in the scope is overheated, the temperature detecting means provided in the vicinity of the solid-state image pickup device. Detects overheating, which activates the power control means. The supply signal control means attenuates or cuts off the drive voltage and the drive current, which are the drive signals supplied to the respective circuits such as the solid-state image sensor and the waveform shaping means, which form the scope, to prevent the overcurrent generated in the device. Suppress. Therefore, overheating of the solid-state image sensor caused by overcurrent is avoided.

[0010]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 shows an embodiment of the present invention. The same parts as those of the electronic endoscope device shown in FIG. 8 are designated by the same reference numerals, and detailed description thereof will be omitted. The electronic endoscope device 100 includes a scope 101, a light source 103, and an endoscope signal processing device 105, and light emitted from the light source 103 is output to the outside via a light guide 107 provided along the scope 101. It is derived and illuminates the observation object 109.

The observation object 109 is imaged by the solid-state image pickup device 111 which constitutes the scope 101, and the solid-state image pickup device 1
The image signal obtained at 11 is input to the waveform shaping unit 113, subjected to required waveform shaping and amplification, and then input to the image signal processing circuit 115 constituting the endoscope signal processing apparatus 105. The endoscope signal processing device 105 further includes a drive circuit 117 that drives the solid-state image sensor 111 and the waveform shaping unit 113 and also drives the solid-state image sensor 111, and the image signal processing circuit 115 and the drive circuit 117.
Are respectively controlled by the CPU 119.

The image signal from the solid-state image sensor 111 input to the image signal processing circuit 115 is converted into a predetermined video signal and then input to an external monitor 121 and an external storage device (not shown). It The image signal processing circuit 115 controls the light source 103 so that the input image signal has a required brightness. Scope 101
Is a first power control unit 123 that controls the drive voltage supplied to the solid-state image sensor 111 and the waveform shaping unit 113, and a second power unit 125 that controls the level of the drive current supplied to the solid-state image sensor 111. Have

The first power control means 123 and the second power control means 125 operate based on the detection signals of the temperature detection means 127 provided in the vicinity of the solid-state image pickup device 111 in the scope 101, and drive current level. Also, at least one of the drive voltages is lowered or at least one of them is cut off. Hereinafter, the temperature detecting means 127, the first power control means 123, and the second power control means 125 will be described. The temperature detecting means 127 has at least one thermosensitive element such as a thermistor, and detects an increase in ambient temperature by a resistance change of the thermosensitive element.

For example, when the thermistor exceeds the set temperature threshold, the resistance value changes greatly. The first power control means 123 and the second power control means 125 control the drive current level and the drive voltage, respectively, in response to the resistance value change of the thermistor. It should be noted that the first power control means 123 and the second power control means 125 have the same operation, and therefore will be described below with reference to the second power control means 125.

FIG. 2 shows a circuit diagram when the thermistor 201 is used as the temperature detecting means 127, and both ends of the thermistor 201 are connected to the power control means 125, respectively. FIG. 3 is a thermistor 201 shown in FIG.
Shows a circuit diagram when is used as a thermistor having a positive temperature coefficient whose resistance value increases when the temperature exceeds a set temperature. One end of the thermistor 201 is connected to the drive circuit 117, the other end is connected to the other end of the resistor R1 whose one end is grounded, and the other end is further connected to the solid-state image sensor 111.

When the ambient temperature rises and exceeds the temperature threshold value set in the thermistor 201, the resistance value of the thermistor 201 increases. Therefore, the thermistor 201 and the resistor R1
Since the voltage division ratio set by and changes, the voltage at the midpoint a becomes low and the level of the drive current is reduced. FIG. 4 shows a circuit diagram when used as a thermistor having a negative temperature coefficient in which the resistance value becomes smaller when the set temperature threshold value is exceeded. One end of the thermistor 201 is grounded, and the other end is connected to the drive circuit 117 via the resistor R2 and the solid-state image sensor 111.

When the ambient temperature rises and exceeds the temperature threshold value set in the thermistor 201, the resistance value of the thermistor 201 decreases. Therefore, the thermistor 201 and the resistor R2
Since the voltage division ratio set by and changes, the voltage at the midpoint a becomes low and the level of the drive current is reduced. As described above, in the embodiments shown in FIGS. 2 to 4, since the control of the drive current level is executed by the thermal element and the single resistor, the apparatus is downsized and simplified, and the degree of freedom of the installation place is expanded. . Therefore, the second power control unit 125 or the first power control unit is provided in each circuit of the scope, for example, the waveform shaping unit 1.
It can be located within 13.

FIG. 5 shows another embodiment of the power control means 125. Thermistor 20 constituting temperature detecting means
One end of 1 is grounded, and the other end is connected to the power source Vc via a resistor R3.
connected to c. The voltage at the midpoint a set by the thermistor 201, the power supply Vcc, and the resistor R3 is input to one end of the comparator 501. Comparator 501
The other end of the reference voltage V is set by a resistor R5 whose one end is grounded and a resistor R4 whose one end is connected to the power supply Vcc.
ref has been entered.

A comparator 501 controls opening / closing of a breaking means 503 such as a semiconductor switch or a relay. When the ambient temperature rises and exceeds the temperature threshold value set in the thermistor 201, the resistance value of the thermistor 201 changes and the voltage at the midpoint a changes. Therefore, the voltage and the reference voltage Vre
Since the output of the comparator that compares with f is inverted, the cutoff means 503 is opened, which reduces the level of the drive current.

In the embodiment shown in FIG. 5, the comparator 50
Since the comparison signal of 1 is derived, the comparison signal can be treated as a high-level and low-level binary signal, which is suitable for digital processing. Therefore, the comparison signal is sent to the CPU.
The control state can be easily displayed on the operation panel of the endoscope signal processing device or on the screen of an external monitor.

The temperature coefficient of the thermistor 201 can be set to either positive or negative by exchanging the reference voltage Vref and the voltage at the midpoint a. Further, the CPU generates the reference voltage Vref according to the type of endoscope,
The temperature threshold value set in the thermistor 201 may be changed according to the type of endoscope.

Further, as shown in FIG. 6, a switch 601 which is closed in a steady state and a switch 603 which is opened in a steady state are connected in parallel, and when the set temperature threshold of the thermistor 201 is exceeded, the switch 601 is opened and the switch is opened. 603 may be closed so that the level of drive current is reduced via resistor R6. In the embodiment described above, the case where the thermistor is used as the heat-sensitive means constituting the temperature detecting means has been described, but a heat-sensitive fuse may be used.

That is, as shown in FIG. 7, the thermal fuse 701 forming the temperature detecting means 127 and the resistor R6 forming the power control means 125 are connected in parallel. When the ambient temperature rises and exceeds the temperature threshold set in the thermal fuse 701, the thermal fuse 701 is blown, and the level of the drive current is reduced by the resistor R6.

Further, the resistor R6 is eliminated, and when the ambient temperature rises and exceeds the temperature threshold value set in the thermal fuse 701, the thermal fuse 701 is melted and the level of the driving current is cut off. Is also good. In this case, since the thermal fuse fulfills the temperature sensing function and the interruption function, the temperature detecting means 127 and the power control means 125 can be used in common and the number of parts can be reduced.

Further, as shown by the arrow, the temperature detecting means 127
A heat sensitive switch 7 such as a bimetal is used as the heat sensitive means constituting the
If the ambient temperature rises and exceeds the temperature threshold value set in the heat sensitive switch 703, the heat sensitive switch 703 is opened and the level of the driving current may be reduced by the resistor R6. Further, the resistor R6 may be eliminated, and the drive current may be cut off by opening the heat-sensitive switch 703 due to the rise in ambient temperature.

The heat-sensitive switch 703 automatically returns and closes when the ambient temperature falls below the set temperature threshold.
Therefore, unlike the thermal fuse described above, continuous use becomes possible and maintenance is facilitated. As described above, in each of the embodiments shown in FIGS. 1 to 7, the case where the first and second power control means are provided in the scope has been described. However, each power control unit may be provided in the image signal processing apparatus to control the drive current level and the drive voltage supplied to the scope, and both in the scope and the image signal processing apparatus. It may be provided.

[0027]

According to the invention described above, the temperature rise of the solid-state image pickup device due to the overcurrent is detected by the temperature detection means provided in the vicinity of the solid-state image pickup device, and the solid-state image pickup device or the like constituting the scope is detected. The drive signal supplied to each circuit is controlled to be attenuated or cut off. Therefore, the overcurrent is suppressed,
As a result, it is possible to avoid overheating that occurs in the solid-state image pickup element, and consequently protect the solid-state image pickup element from heat.

[Brief description of drawings]

FIG. 1 is a block diagram showing an embodiment of the present invention.

FIG. 2 is a diagram showing a first embodiment of the temperature detecting means shown in FIG.

FIG. 3 is a circuit diagram showing temperature detection means and second power control means shown in FIG.

FIG. 4 is a circuit diagram showing temperature detection means and second power control means shown in FIG.

FIG. 5 is a circuit diagram showing a temperature detecting means and a second power control means shown in FIG.

FIG. 6 is a circuit diagram showing temperature detection means and second power control means shown in FIG.

FIG. 7 is a diagram showing a second embodiment of the temperature detecting means shown in FIG.

FIG. 8 is a block diagram showing a conventional electronic endoscope apparatus.

[Explanation of symbols]

 100 electronic endoscope device 101 scope 103 light source 105 endoscope signal processing device 107 light guide 109 observation object 111 solid-state image sensor 113 waveform shaping means 115 image signal processing device 117 drive circuit 119 CPU 121 monitor 123, 125 power control means 127 Temperature detecting means 201 Thermistor 501 Comparator 503 Breaking means 601 603 Switch 701 Thermal fuse 703 Thermal switch

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Yasuo Komatsu 2-43-2 Hatagaya, Shibuya-ku, Tokyo Inside Olympus Optical Co., Ltd.

Claims (1)

[Claims] 1. An object to be observed is imaged by a solid-state image sensor provided at the tip of a scope, and a signal photoelectrically converted by the solid-state image sensor is shaped by a waveform shaping means to a desired waveform and then provided outside the scope. In the electronic endoscope apparatus for observing the observation object by deriving the required signal processing by deriving the signal processing apparatus, a temperature detecting unit arranged in the vicinity of the solid-state image sensor, the scope, and And a power control unit that is provided in at least one of the signal processing devices and controls a drive signal supplied to at least one of the solid-state image sensor and the waveform shaping unit, and the vicinity of the solid-state image sensor due to generation of an overcurrent. Is detected by the temperature detection means, the power control means is operated to operate at least one of the solid-state imaging device and the waveform shaping means. An electronic endoscope device characterized in that a drive signal supplied to the device is controlled.