JPH0362086B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an endoscope apparatus, and more particularly to an endoscope apparatus equipped with a safety circuit.

In recent years, the application of microcomputers to various devices has progressed, and various proposals have been made for application to endoscope devices. One problem with this application is that since endoscopes are used to diagnose the human body, minimum safety measures are required even if the microcomputer's CPU goes out of control due to inadvertent noise or heat. The point is that In particular, in endoscopes equipped with a light source device, when the CPU goes out of control, illumination light is not supplied to the subject area, making it impossible to observe the subject area through the eyepiece of the endoscope, making it safe. It has been pointed out that there are problems with the above.

The present invention was made in view of the above-mentioned circumstances, and it is an object of the present invention to provide an endoscope device that can ensure a minimum level of safety even if the CPU goes out of control.

The present invention will be described below with reference to the drawings.

As shown in FIG. 1, a microcomputer consisting of a CPU 2, an I/O port 4, a ROM 6, a chip select IC 8, and an oscillator 10 is provided in the light source device (not shown). CPU2 is
The address terminals Aφ to A15 are connected to the I/O port 4, ROM 6, and chip select IC 8 via the address bus 13, and address data is supplied from the CPU 2 to each device. Also
CPU2 has its data terminals Dφ to D7 as data terminals.
It is connected to the I/O port 4 and the ROM 6 via the bus 15, and data is read from the ROM 6 to the CPU 2, and between the I/O port 4 and the CPU 2,
Data is transferred.

Input terminals PAφ and PA1 of I/O port 4 are
Resistor 1 connected between power supply Vcc and ground, respectively
0, 12 and lamp light intensity setting switch 14, 1
It is connected to the connection point between the 6 series circuits. Furthermore, a zero-cross detection circuit 20 is connected to the input terminal PC of the I/O port 4 for detecting the zero-cross point of the AC voltage supplied from the commercial AC power supply 18 . Furthermore, the I/O where the lamp lighting signal is generated is
The output terminal PB of the O port is connected to the base of the first transistor 24 via the resistor 22. The emitter of this transistor 24 is grounded, and its collector is connected via a photo diode of a photo coupler 26 and a resistor 28 to the power supply V _DD . The commercial AC power supply 18 is a light source 30
A resistor 34 and the above-mentioned photo coupler 26 are connected to the light source 30 via a triax 32 for phase control of the power supplied to the light source 30, and between the connection point between the triax 32 and the light source 30 and the gate of the triax 32 A triax is connected to fire the triax 32 at predetermined intervals.

Chip select IC8 is connected to the chip select terminal of I/O port 4, and the ROM
Connected to the chip enable terminal of 6,
The CPU 2 selects chips according to address data. Memory read signal terminal and machine cycle signal terminal 1 of CPU2
is connected to OR36, the output of this OR36 and the output of inverter 37 connected to the chip enable signal line are connected to NOR38,
The output of NOR 38 is connected to latch 40. The output of latch 40 is connected to the second
The collector and emitter of this second transistor 44 are connected between the photo diode of the photo coupler 26 and ground.

The light source device configured as described above is operated as follows. When the commercial AC power supply voltage is supplied to the zero-cross detection circuit 20 as shown in FIG. 2a, the zero-cross detection circuit 20 detects the zero-cross point and generates a zero-cross signal as shown in FIG. Occur. The generated zero-cross signal is input to the input terminal PC of the I/O port 4. Here, turn the lamp light intensity setting switch 16.
is closed, the input terminal of I/O port 4
A low level signal is supplied to PAφ. This low level signal and zero crossing signal are connected to the data bus 15.
The CPU 2 reads the data of the programmed delay time t ₁ from the ROM 6 based on the applied signal, and outputs the data to the output terminal of the I/O port 4 as shown in Fig. 2c. A low level signal is generated for a delay time t ₁ from the zero crossing point, and then a high level signal is generated for a time t ₂ until the next zero crossing point. Therefore, the first transistor 24 is turned off during the delay time t ₁ and the first transistor 24 is turned on during the time t ₂ . During the ON time _t2 of the first transistor 24, the photodiode of the photocoupler 26 emits light, and its phototriac is turned on and the triac 32 is turned on.
turns on. As a result, the light source 30 is supplied with power from the AC power supply 18 during the time _t2 , and the light source 30 is
A current as shown in FIG. 2d is continuously supplied to the lamp, and the lamp is turned on at an appropriate predetermined brightness.

When the lamp light intensity setting switch 14 is closed instead of the lamp light intensity setting switch 16, the delay time _t3 is read out instead of the delay time _t1 , and the second An output signal as shown in Figure e is generated. Accordingly, a current as shown in FIG. 2f is supplied to the light source 30, causing it to be illuminated at a modified and appropriate constant brightness.

By counting zero-crossing signals as shown in Figure 2b, the CPU 2 can determine whether the frequency of the AC power source is 50Hz or 60Hz, and by selecting an appropriate delay time based on the determination. Therefore, the light source 30 can maintain the specified brightness regardless of whether the frequency is 50 Hz or 60 Hz.

Next, the timing of the CPU 2 when the CPU 2 is operating normally and when the CPU 2 goes out of control due to noise, heat, etc. will be explained with reference to FIG. FIG. 3 shows the timing in a machine cycle for fetching an instruction code, and the oscillator 10 supplies the CPU 2 with a basic clock as shown in FIG. 3a. Chip select IC8 to ROM6
A signal as shown in FIG. 3b is applied to the chip enable terminal of the ROM 6, and when this signal becomes low level, the ROM 6 is maintained in a readable state. When data is read from the memory to the CPU 2 as shown in FIG. 3c, the memory read terminal is maintained at a low level, and
Machine cycle signal terminal 1 when the instruction code is fetched to CPU 2 as shown in Figure 3d.
is similarly maintained at a low level. Therefore, the third
As shown in Figure e, while the output of the OR 36 is at a low level, the CPU 2 is in the instruction reading operation. If the chip enable terminal of ROM6 is at a low level during this period, it means that data is being read from ROM6. Therefore, the output of the inverter 37 becomes as shown in FIG. 3f, and as a result of this output and the output of the OR 36 being supplied to the NOR 38, the output of the NOR 38 remains at a low level as shown in FIG. 3g. , and the second transistor 44 remains in the off state. In this state, the current supplied to the light source 30 is controlled depending on the on/off operation of the first transistor 24.

When CPU2 goes out of control, CPU2
This results in fetching instructions from other memory. That is, the chip enable terminal of ROM6
CE is held high and instructions are fetched even during periods when no chips are selected. Therefore, the output of the inverter 37 becomes low level and
The output of OR 36 is held low and NOR 38 generates a high signal, as shown in FIG. 3h, which is held in latch 40. As a result, a signal as shown in FIG. As shown in Figure 2, a non-phase controlled alternating current is supplied and the lamp is turned on at maximum brightness to ensure the field of view within the endoscope connection.

In the embodiment described above, while the second transistor 44 is in the on state, the alternating current is supplied to the light source 30 as it is, but the phase-controlled alternating current is supplied to the light source 30 and the limited You may also set the brightness.

According to the above-described light source device, even if the CPU goes out of control, the endoscope light source continues to be turned on, thereby ensuring the safety of the endoscope device.

[Brief explanation of drawings]

FIG. 1 is a circuit diagram showing a microcomputer and its related circuits incorporated in the endoscope apparatus of the present invention, FIG. 2 is a waveform diagram showing waveforms of each part in the phase control circuit of FIG. 1, and FIG. is a tamming chart showing tamming in each part of the CPU and the CPU runaway detection circuit. 2...CPU, 4...I/O port, 6...
ROM, 8... Chip select IC, 10...
Oscillator, 13... Address bus, 15... Data bus, 20... Zero cross detection circuit, 30...
...Light source, 40...Latch.

Claims (1)

[Claims] 1 An endoscope that adjusts brightness, comprising means for controlling the electric power supplied to the light source for an endoscope, and a microprocessor for processing a setting signal given from the outside and generating a control signal to the control means. The mirror device further comprises means for detecting runaway of the microprocessor, and means for causing the endoscope light source to emit light at a preset constant brightness state in response to the detection output. Endoscope equipment.