JPS6132641Y2 - - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to a light source device in an endoscope for observing inside a body cavity, and is particularly intended to improve the operability and safety of the light source device.

An endoscope inserts a flexible thin tube containing a light guide made of optical glass fiber into a body cavity.
The image of the subject to be examined from the endoscope window at the tip of the tube is guided to the viewing section of the hand control section for observation.
A powerful light source device is required to illuminate the observation surface within the body cavity. Conventionally, a xenon discharge tube lighting device has been used as this kind of light source device, but the discharge tube requires application of a high voltage to start the discharge when the discharge tube starts lighting. As a means for applying a high voltage to start lighting, in conventional devices, this high voltage is generated while the start button is pressed to measure the application of the discharge tube, and when it is visually confirmed that the discharge tube has reached the lighting connection state, the This was done by releasing a button.

According to such a lighting starting operation, it is necessary to keep pressing the start button until the lighting connection state is reached, and this high voltage application imposes harsh conditions on the discharge tube and its circuit device. Continuing to apply a high voltage for an unnecessarily long period of time even after the discharge tube has reached a sustained lighting state may cause deterioration in the durability of the tube.

On the other hand, since the endoscope is used in a particular manner, that is, a part of the device is inserted into a body cavity, extreme care must be taken to avoid electrical leakage to the high-voltage endoscope section of the light source device.

Therefore, the present invention aims to provide a device configuration that compensates for the drawbacks of conventional devices and is effective in ensuring safety in view of the special characteristics of light source devices in endoscopes.

Hereinafter, the gist of the device of the present invention will be explained in more detail with reference to the illustrated embodiments.

Figure 1 is a circuit diagram of one embodiment of the present invention, in which two DC power supplies E ₁ and E ₂ are provided, each independently transforming and rectifying the output from an AC main power supply (not shown). There is. These DC power supplies include an initial discharge connection power supply E ₁ (supply voltage 70 volts) that supplies the initial discharge voltage (for example, 65 volts) necessary to sustain the discharge when lighting the discharge tube F; A power supply E ₂ (power supply voltage: 17 volts) for normal discharge supplies the lighting voltage (for example, 15 volts) that needs to be applied to the discharge tube F after the lamp is lit.

A high resistance R ₁ is connected in series to the power supply E ₁ for initial discharge connection, and a diode D ₁ is connected in series in the forward direction to the power supply E ₂ for normal discharge, and these two power supply circuits A discharge power supply circuit for the discharge tube F is configured by connecting them in parallel. RY is a relay and its drive circuit, which is a Zener diode.
It is connected to the power supply circuit under series connection with _D2 . A capacitor C is connected in parallel to the series connection between the drive circuit RY and the Zener diode _D2 , and forms a CR time-fixing circuit with the high resistance _R1 . V momentarily outputs a DC high voltage current when AC power is input, and generates a high voltage for starting the discharge tube F (for example, 20
This is a well-known high voltage application device that generates a high voltage (kilovolt), and in FIG. The voltage is input to a high voltage application device V, and a switch S responsive to the drive circuit RY is inserted in the middle of the connection line.

The specific configuration of the high voltage application device V is known, and for example, the primary coil of a transformer is connected to the input circuit from the main power source via a rectifier,
Connect the secondary coil of the transformer to the connecting wires connected to the left and right sides of the high voltage application device V in FIG. (inserted in the middle of the connecting wire with the side) so that the voltage between the terminals of the capacitor C is
At the same time, when an input is applied to the primary coil, a high voltage instantaneously generated in the secondary coil is applied to the discharge tube F. Further, the cathode side of the discharge tube F (lower side in the figure) is connected to the secondary side circuit of the high voltage application device V, so that high voltage is not applied to circuits other than the discharge tube F. Additionally, _R2 is a low resistance connected in series to the discharge tube F. Furthermore, the mechanical part indicated by the dotted line in the figure is a timer M that acts on the drive circuit RY.
Any configuration such as an electronic type, a mechanical type, or a bimetal type can be used to activate the device when a predetermined time has elapsed. Note that this timer M may be configured to act directly on the high voltage application device V.

FIG. 2 is a time chart showing the operating state of the main parts of the device of the present invention, and the time charts of the high voltage application device V and the discharge tube both show the operating principle and timing of the operation. FIG. 3 is a longitudinal sectional side view of the main mechanism showing an advanced embodiment of the device of the present invention. A switching operation piece 6 of a switch mechanism 5 for controlling the power supply circuit and the like of the high voltage application device V of the first illustrated circuit is exposed to the entry area of the shaft body 4 that enters into the housing.

Although the switch mechanism 5 shown in FIG. 3 is not shown in FIG. 1, since the switch mechanism 5 controls the power supply circuit of the high voltage application device V, it is usually connected to the switch S. connected in series. or,
Reference numerals 7 and 7 indicate connecting pins that change the electrical state when the connecting mechanism section 2 and the connecting section 3 are connected.

According to the device of the present invention having such a configuration,
When using the light source device, at the same time as turning on the main power, the voltage for initial discharge connection E ₁ and the power supply for normal discharge E ₂
outputs, and the power supply E ₁ passes through a high resistance R ₁ , and
Power supply E ₂ passes through diode D ₁ to capacitor C
Start charging. When the voltage between the terminals of the capacitor C, that is, the voltage applied to the relay and its drive circuit RY increases as shown in the second diagram and reaches the initial discharge connection voltage, the breakdown voltage operation of the Zener diode _D2 causes the drive circuit RY to A current flows, and its operation closes the responsive switch S, generating a high voltage in the high voltage applying device V. On the other hand, when the power supplies E ₁ and E ₂ output, the voltage of E ₁ charges the capacitor C because the power supply voltage of E ₁ is higher than that of E ₂ .
As mentioned above, since the capacitor C terminal and the discharge tube F are connected via the secondary coil of the high voltage application device V, the terminals of the capacitor C reach the initial discharge voltage (65 volts). At the same time that voltage is applied to the discharge tube F, a high voltage (20 kilovolts) generated by the high voltage application device V is momentarily applied between the poles of the discharge tube F, thereby causing the discharge tube F to start discharge. , the charge in the capacitor C is rapidly discharged through the tube V and the low resistance _R2 , so the voltage between its terminals drops and the operating current to the drive circuit RY, which is regulated by the Zener diode _D2 , is cut off, and its response is The switch S becomes open and interrupts the output operation of the high voltage application device V.

If the discharge of the discharge tube F continues after the voltage across the terminals of the capacitor C drops, a current path is formed between the electrodes of the discharge tube, so that the voltage of the power source E ₂ is applied to the discharge tube. F while the power E ₁
The voltage of R ₁ is a high resistance inserted in the power supply circuit.
In this state, the discharge tube F continues to discharge and is lit by the power supplied by the power source _E2 .

Furthermore, if the discharge tube F does not continue to discharge due to the high voltage applied during the operation of the drive circuit RY, a current path is not formed between the electrodes of the discharge tube, so that the power supply E ₁ is connected to both terminals of the capacitor C. , the capacitor C starts charging again until the voltage between the terminals reaches the discharge sustaining voltage, and after time _T1 in FIG. 2 has elapsed, the high voltage generation operation is repeated. This repetitive operation is continued with the time width and period of T _H and T _I shown in FIG. 2 until the discharge tube F is lit.

In the device of the present invention, by appropriately selecting the time constant determined by the capacitor C and the low resistance _R2 , the application time of the high voltage applied to the discharge tube F is adjusted, and the high voltage is applied to the discharge tube F more than necessary. The capacitor C and high resistance _R1 prevent the electrodes of the discharge tube F from being consumed by the high voltage of By appropriately adjusting the time constant, it is possible to turn on the lamp at any time after the power is turned on, when other control circuits are not adversely affected.

In the device of the present invention, the power source is divided into the power source E ₁ for initial discharge connection and the power source E ₂ for normal discharge, so the resistance values of the resistors R ₁ and R ₂ can be freely selected. In addition to being able to freely adjust the time constant, it is also possible to insert a smoothing capacitor into the power supply circuit of power supply E ₂ to prevent flickering in the discharge tube F. If the capacity of C is increased, there is a risk that an enormous amount of energy will be accumulated compared to the energy required for sustaining the discharge and the discharge tube F will deteriorate or be damaged, but there is no risk of this happening.

By the way, if the discharge tube F or the circuit section does not turn on due to functional deterioration, the above repetitive operation is meaningless, so the high voltage application operation for starting the lighting is performed for a certain period of time by the timer M. This is effective in terms of power consumption and circuit protection by stopping the process after the elapsed time has elapsed.

Furthermore, in the above-mentioned operation, the device of the present invention controls the high voltage generation time to only the minimum time required to start the lighting, reducing the risk of accidents due to electrical leakage. , safety can be further improved by using the mechanical device shown in the third figure. That is, for example, when the endoscope side connection part 3 is connected to the connection mechanism part 2 of the light source device housing 1 by connecting the switch mechanism 5 or the connection pins 7, 7 in series to the switch S, Input from main power supply to high voltage application device V
By turning it off, you can prevent the generation of high voltage and prevent high voltage current from leaking to the operator or patient through the endoscope. Then, by pulling out the endoscope side connection part 3 from the connection mechanism part 2, the power input to the high voltage application device V is turned on, and if the light source device has been started once, the start operation is performed. It is possible to shift the device to the lighting start state without repeating the process. Even if the timer M is provided, it operates in the same way as long as the timer does not turn off the drive circuit RY.

As described above, the device of the present invention automatically generates and applies a high voltage for starting lighting to the discharge tube intermittently and repeatedly until the lighting state is reached, so the operation is extremely simple, and the high voltage Since the generation and application of energy is carried out in the shortest time necessary when starting the lighting, it is possible to prevent deterioration of the durability of the discharge tube and circuit equipment as much as possible, and to reduce the danger to the human body as much as possible. This has the advantage of allowing the lamp to be turned on at will during times when the control circuit is not adversely affected by high frequencies and high voltages.

[Brief explanation of drawings]

FIG. 1 is a circuit diagram showing an embodiment of the device of the present invention;
Fig. 2 is a time chart showing the operating state of the main parts in the above embodiment of the device of the present invention, and Fig. 3 is a partially longitudinal side view showing an embodiment of an effective connecting part attached to the device of the present invention. be. E ₁ ... Power supply for initial discharge connection, E ₂ ... Power supply for normal discharge, R ₁ ... High resistance, R ₂ ... Low resistance, D ₁ ...
...Diode, RY...Relay and drive circuit, D ₂
... Zener diode, C ... capacitor,
V...High voltage application device, S...Response switch, F
...discharge tube.

Claims (1)

[Scope of utility model registration request] a first power supply circuit consisting of an initial discharge connection power supply and a high resistance connected in series to the initial discharge connection power supply; a normal discharge power supply connected in parallel to the first power supply circuit; a second power supply circuit consisting of a diode connected in the forward direction to the power supply for the
A discharge tube constitutes a discharge current circuit by the first power supply circuit and the second power supply circuit, and at the time of power-on and recharging, a CR time-fixing circuit is constituted between the high resistance and the above-mentioned high resistance. A capacitor that is discharged through a low resistance connected in series with the discharge tube during the starting discharge of the discharge tube, and a relay drive that is connected in parallel with the capacitor and operates when the capacitor receives charge from the power source and reaches a predetermined voltage. A high voltage that is placed under the control of a circuit and a relay switch that responds to the relay drive circuit, and applies a high voltage for starting discharge intermittently to the discharge tube until it starts lighting, depending on the operation or non-operation of the relay drive circuit. The time from when the power is turned on until the relay drive circuit operates and the subsequent non-operation time of the relay drive circuit are as described above.
A light source device for an endoscope, wherein the time constant of the CR time constant circuit is adjusted, and the operating time of the relay drive circuit is adjusted by the time constant of the low resistance and the capacitor.