JPH07299030A - Xenon lamp lighting device of light source device for endoscope - Google Patents

Abstract

PURPOSE:To provide an xenon lamp lighting device of light source device for endoscope which is used as a DC constant voltage source as the power source, and minimized in heating and wasteful power consumption in a circuit. CONSTITUTION:A DC constant voltage source 1, a rated voltage source 1 for supplying the DC constant voltage of about the rated voltage of an xenon lamp 2 to a constant current control circuit 5, and high voltage sources 1a, 1b for supplying a DC constant voltage higher than the rated voltage of the xenon lamp 2 to the constant current control circuit 5. This device also has DC voltage source switching means 6, 7 for detecting the lighting state of the xenon lamp 2 and switching the DC voltage source in such a manner as to connect the high voltage sources 1a, 1b to the constant current control circuit 5 until a prescribed time passes after the lighting by a starter 3, and connect the rated voltage source 1a to the constant current control circuit 5 after the lapse of the prescribed time after the lighting by the starter 3.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a xenon lamp lighting device for an endoscope light source device used for supplying illumination light to an endoscope.

[0002]

2. Description of the Related Art Conventionally, a power source for lighting a xenon lamp has been commercially available as a power source dedicated to the lamp, but all of them use a commercial AC constant voltage source.

[0003]

However, when such a commercial AC constant voltage source is used as a power source, the portability of the light source device is limited because of poor portability. Therefore, if a DC constant voltage source such as a battery is used as a power source, portability can be improved.

FIG. 3 shows a lighting circuit when such a DC constant voltage source 1 is used as a power source, and a xenon lamp 2 is provided.
To turn on, the voltage boosted by the booster circuit 4 is applied to the starter 3 to cause a dielectric breakdown between both electrodes of the xenon lamp 2 to turn on the xenon lamp 2, and then a DC constant voltage source The constant voltage of 1 is converted into a constant current by the constant current control circuit 5 and applied to the xenon lamp 2,
The xenon lamp 2 is lit continuously.

FIG. 4 shows the time variation of the inter-electrode voltage of the xenon lamp 2 during the operation of the starter 3, the current flowing out from the constant current control circuit 5, and the discharge current from the lighting capacitor C1. Is.

Simultaneously with the operation of the starter 3, discharge from the lighting capacitor C1 is started, and the inter-electrode voltage of the xenon lamp 2 drops to Vx in FIG. At this time, when the inter-electrode voltage falls below the voltage Va of the DC constant voltage source 1, the current flows out of the constant current control circuit 5 for the first time, and the continuous lighting is started.

If Vx does not fall below Va, no current flows from the constant current control circuit 5, and the discharge from the lighting capacitor C1 ends, and at the same time, the emission of the xenon lamp 2 stops. In other words, if current does not flow from the constant current control circuit 5 while the discharge from the lighting capacitor C1 continues, continuous lighting cannot be performed.

The inter-electrode voltage Vx immediately after the operation of the starter 3 varies depending on various conditions such as the variation of the xenon lamp 2 and the variation of the temperature, and varies every time the starter 3 operates. The fluctuation range of this Vx is about 10 V, and if the voltage Va of the DC constant voltage power supply 1 is set to a low value, the probability of continuous lighting decreases (lighting error).

Therefore, immediately after lighting, the xenon lamp 2
In order to prevent the lamp from being turned off, it is necessary to supply a voltage higher than the rated voltage by about 10 V from the DC constant voltage source 1 to the xenon lamp 2.

However, after the xenon lamp 2 shifts to continuous lighting and the inter-electrode voltage of the xenon lamp 2 stabilizes, a voltage of 10 V exceeding the rated voltage is consumed by the constant current control circuit 5 and becomes heat. Is released. Therefore, there is a problem of unnecessary power consumption and circuit heat generation.

Therefore, an object of the present invention is to provide a xenon lamp lighting device for an endoscope light source device which uses a direct current constant voltage source as a power source and has less heat generation in the circuit and less wasteful power consumption.

[0012]

To achieve the above object, a xenon lamp lighting device of a light source device for an endoscope according to the present invention comprises a DC constant voltage source for supplying a DC constant voltage,
A starter connected to the xenon lamp in order to cause dielectric breakdown between both electrodes of the xenon lamp to light the xenon lamp, and a voltage supplied from the DC constant voltage source is boosted to a voltage at which the starter operates. A booster circuit for applying the voltage to the starter, and a constant voltage output from the DC constant voltage source to convert the constant voltage output from the DC constant voltage source into a constant current so that the xenon lamp lit by the starter is continuously lit as it is. In a xenon lamp lighting device having a constant current control circuit for applying to the lamp, a lamp lighting state monitoring means for monitoring a lighting state of the xenon lamp, and the starter in response to a monitoring result by the lamp lighting state monitoring means. After the xenon lamp is turned on, the output voltage of the DC constant voltage source is Characterized in that a power supply control means for reducing until the voltage necessary for the continuous lighting of Senonranpu.

Further, the xenon lamp lighting device of the light source device for an endoscope of the present invention is, as the DC constant voltage source, rated for supplying a DC constant voltage substantially equal to the rated voltage of the xenon lamp to the constant current control circuit. A voltage source and a high voltage source for supplying a DC constant voltage higher than the rated voltage of the xenon lamp to the constant current control circuit are provided, and the lighting state of the xenon lamp is detected, and after lighting by the starter. The high voltage source is connected to the constant current control circuit until a predetermined time elapses, and the DC voltage source is switched to connect the rated voltage source to the constant current control circuit after a predetermined time elapses after lighting by the starter. It is characterized in that a switching means is provided.

[0014]

Embodiments will be described with reference to the drawings. Figure 1
The xenon lamp lighting circuit provided in the light source device for endoscopes is shown.

In the figure, reference numeral 1 is a direct current constant voltage source using a battery. As long as it supplies a constant DC voltage, not only the battery but also various kinds of general-purpose switching regulators or transformer power supplies can be used. it can. However, if a battery is used, portability is good, and if a secondary battery is used, recharging is possible.

The DC constant voltage source 1 is composed of two batteries 1a and 1b connected in series, and the first battery 1a has an electromotive force of 15 V, which is the rated voltage of the xenon lamp 2. The second battery 1b has an electromotive force of 10 V, for example. Therefore, as the high voltage source higher than the rated voltage, the first and second batteries 1a and 1b are connected in series and used.

Reference numeral 2 is a xenon lamp for supplying illumination light to the illumination light guide of the endoscope. The input voltage on the anode side of the xenon lamp 2 is, for example, 100 to 2
A starter 3 that causes a dielectric breakdown between the electrodes of the xenon lamp 2 to turn on the xenon lamp 2 at 00 volts is connected in series.

Reference numeral 4 is a DC boosting circuit for boosting the voltage supplied from the DC constant voltage source 1 to a voltage at which the starter 3 operates and applying it to the starter 3. For example, a Cockcroft-Walton voltage doubler rectifier circuit. Etc. can be used.

The output end of the DC boosting circuit 4 is connected to the input end of the starter 3, and between the connecting end A and the cathode of the xenon lamp 2, a resistor R1 for lighting and a capacitor C are provided.
1 and 1 are connected in series via the ground.

Reference numeral 5 is for converting the constant voltage output from the DC constant voltage source 1 into a constant current and applying it to the xenon lamp 2 in order to continuously light the xenon lamp 2 which has been lit by the starter 3. It is a constant current control circuit, and for example, a series regulation type constant current circuit can be used. D1 is a backflow prevention diode. In the present invention, various constant current control circuits such as a dropper type, a chopper type and the like can be used.

The input end of the constant current control circuit 5 and the input end of the DC boosting circuit 4 are connected to each other and connected to the DC constant voltage source 1 via the relay switch 6. A capacitor C2 is connected between the connection portion and the ground (that is, the negative electrode of the DC constant voltage source 1).

In the relay switch 6, in the state where no current is passed through the electromagnetic coil L, the first and second serially connected
The changeover switch SW is connected to both batteries 1a and 1b of
A voltage of 25 V is output from the DC constant voltage source 1. When a certain current or more is applied to the electromagnetic coil L, the changeover switch SW is switched to only the first battery 1a, and a voltage of 15 V is output from the DC constant voltage source 1.

Reference numeral 7 denotes a relay drive circuit which detects the lighting state of the xenon lamp 2 and switches the relay switch 6. In this relay drive circuit 7, the output end of the optical sensor SE that receives the light emitted from the xenon lamp 2 and generates a voltage is input to the positive side of the comparator CP via the RC circuit including the resistor R3 and the capacitor C3. Connected to the end.

Instead of receiving light by the optical sensor SE,
The lamp current of the xenon lamp 2 may be monitored. The reference voltage is input to the negative input terminal of the comparator CP. D3 is a diode for letting out the electric charge charged in the capacitor C3 when the output from the optical sensor SE is exhausted.

The output terminal of the comparator CP is connected to the base of the switching transistor TR connected to the electromagnetic coil L of the relay switch 6 via the resistor R4. R5 is a resistor for pull-up.

Next, the operation of the above embodiment will be described. When the circuit is not working, relay switch 6
1 is connected to both the first and second batteries 1a and 1b connected in series as shown in FIG. 1, and is in a state in which a high voltage of 25 V is applied to the circuit.

When the DC boosting circuit 4 is operated to light the xenon lamp 2, the output voltage of the DC boosting circuit 4 is charged in the lighting capacitor C1 through the lighting resistor R1.

When the potential of the input terminal A of the starter 3 reaches the operating voltage of the starter 3, the xenon lamp 2
Spark discharge occurs between both electrodes, and the impedance between the electrodes instantly becomes almost zero. Then, the electric charge of the lighting capacitor C1 flows into the xenon lamp 2 via the resistor R1 and the starter 3, and the xenon lamp 2 is lit.

Almost at the same time, the DC constant voltage source 1
From the first and second batteries 1a, 1b having a total of 25 volts,
A constant current passing through the constant current control circuit 5 flows into the xenon lamp 2 via the diode D1 and the xenon lamp 2
Starts continuous lighting.

Then, as shown in FIG. 2, when the xenon lamp 2 is turned on, the output from the photosensor SE becomes a high level, and the voltage passes through the RC circuit and the input voltage of the positive input terminal of the comparator CP. Rises slowly.

The input voltage reaches the reference voltage input to the negative side input terminal of the comparator CP after a predetermined time t1. This predetermined time t1 is set to a time until the inter-electrode voltage of the xenon lamp 2 becomes stable and can be continuously lit at a rated voltage of 15 V without any problem.

When the voltage on the positive side input terminal of the comparator CP reaches the reference voltage input on the negative side, the switching transistor T is output from the output terminal of the comparator CP.
A voltage is output to the base of R and the switching transistor TR is turned on.

Then, the electromagnetic coil L of the relay switch 6
A current flows through the switching switch SW, and the voltage supplied from the DC constant voltage source 1 to the circuit drops to 15 volts, which is the rated voltage of the xenon lamp 2. During the time Δt required for switching the relay switch 6, current is supplied from the capacitor C2, so that the lamp current is not interrupted.

In this way, after the xenon lamp 2 is in a stable lighting state, the supply voltage from the DC constant voltage source 1 is reduced to 15 V which is the rated voltage of the xenon lamp 2 and constant current control is performed. Power consumption and heat generation in the circuit 5 are greatly suppressed.

[0035]

According to the present invention, since the direct current constant voltage source is used as the power source of the xenon lamp, the portability of the light source device can be improved. It can have high portability. Then, the voltage required for initial lighting of the xenon lamp is supplied to the constant current control circuit when the starter lights up, and the low voltage required for continuous lighting of the xenon lamp is supplied to the constant current control circuit after lighting by the starter. I did so,
After the voltage between the electrodes of the xenon lamp is stabilized, it is possible to suppress unnecessary power consumption and heat generation in the circuit, and to stably and continuously light the xenon lamp.

[Brief description of drawings]

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

FIG. 2 is a time chart diagram showing the operation of the embodiment of the present invention.

FIG. 3 is a block diagram of a xenon lamp lighting circuit using a DC constant voltage source.

FIG. 4 is a diagram showing a change in voltage between electrodes of a xenon lamp.

[Explanation of symbols]

 1 DC constant voltage source 2 Xenon lamp 3 Starter 4 DC booster circuit 5 Constant current control circuit 6 Relay switch 7 Relay drive circuit

Claims (2)

[Claims] 1. A DC constant voltage source for supplying a constant DC voltage, and a starter connected to the xenon lamp for causing a dielectric breakdown between both electrodes of the xenon lamp to light the xenon lamp. A booster circuit for boosting the voltage supplied from the DC constant voltage source to a voltage at which the starter operates and applying the booster circuit to the starter, and for continuously lighting the xenon lamp lit by the starter as it is. In a xenon lamp lighting device having a constant current control circuit for converting a constant voltage output from a DC constant voltage source into a constant current and applying it to the xenon lamp, a lamp lighting state for monitoring the lighting state of the xenon lamp. The xenon lamp by the starter in response to the monitoring result by the monitoring means and the lamp lighting state monitoring means. After lighting, the power supply control means for lowering the output voltage of the DC constant voltage source to a voltage required for continuous lighting of the xenon lamp is provided as compared with the time of lighting, and the xenon of the light source device for an endoscope is provided. Lamp lighting device. 2. A DC constant voltage source for supplying a DC constant voltage, and a starter connected to the xenon lamp for causing a dielectric breakdown between both electrodes of the xenon lamp to light the xenon lamp. A booster circuit for boosting the voltage supplied from the DC constant voltage source to a voltage at which the starter operates and applying the booster circuit to the starter, and for continuously lighting the xenon lamp lit by the starter as it is. In a xenon lamp lighting device having a constant current control circuit for converting a constant voltage output from a DC constant voltage source into a constant current and applying it to the xenon lamp, as a DC constant voltage source, a rated xenon lamp is used. Higher than the rated voltage source for supplying the DC constant voltage of the voltage to the above constant current control circuit and the rated voltage of the above xenon lamp. A high voltage source for supplying a constant DC voltage to the constant current control circuit is provided, and the high voltage source is detected until the predetermined time elapses after detecting the lighting state of the xenon lamp and lighting by the starter. Is connected to the constant current control circuit, and a direct current voltage source switching means is provided for switching to connect the rated voltage source to the constant current control circuit when a predetermined time has elapsed after lighting by the starter. Xenon lamp lighting device for light source device for endoscopes.