JPH0752678B2 - Lamp switching device - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a lamp switching device that detects an abnormality of an incandescent light bulb using a filament such as a halogen lamp without omission and switches to a spare incandescent light bulb.

[Prior Art] Generally, an incandescent light bulb with high illuminance is often used as a light source for illumination used in a CCD camera or the like. However, this incandescent light bulb has a relatively short life. When an incandescent lamp reaches the end of its life, it will not emit light due to the filament being cut off, or a part of the filament will be in a short-circuited state, resulting in a large change in illuminance. When the illuminance changes drastically, it may be necessary to replace the incandescent lamp well before the expected life time of the incandescent lamp when it is used in an environment where it has other adverse effects, such as when it is used in a production line. for that reason,
There is a drawback that maintenance becomes complicated and running cost becomes high.

Therefore, in order to eliminate such a defect, advance notice detection of a lamp burnout is required, but at present, there is no effective detection method. Therefore, the fusing characteristics of the incandescent lamp are important for finding an effective detection method. This will be described by taking a halogen lamp as an example.

When the halogen lamp has reached the end of its life, its filament is cut (blown) and it does not light up. FIG. 4 shows the characteristics of the current flowing through the halogen lamp at the time of this blow. As can be seen from this figure, the fusing of the filament does not occur completely at once, but rather breaks, so that each part of the filament proceeds while being short-circuited. For this reason, the current increases and decreases at each stage, and finally the process of completely melting is followed. Then, the filament is completely melted within a few seconds at the longest after the melting phenomenon starts.

By the way, a switching power supply is generally used as a power supply for supplying power to halogen lamps, and this has an overcurrent prevention function that prevents a certain amount of current from flowing in order to protect its own circuit elements. There is. Fig. 5 shows an example of this overcurrent drooping characteristic. The rated current is 8.3A, and the voltage is drooped by about 115% (9.5A) or more to limit the current.

This causes the lamp to melt and the current to increase, increasing the current to 9.5A.
When the temperature reaches 1, the switching power supply functions to stop this fusing phenomenon, and the halogen lamp continues to be lit while a part of the filament is broken (half cut state or part short circuit state). This current limited state is around point a in FIG. Since it stops at this point, the service life will be somewhat extended, but eventually it will melt. If this state can be detected, the lamp abnormality can be effectively detected.

Also, depending on the lamp, the filament may completely melt before exceeding 9.5A. The rate of complete fusing without passing through the half-cut state is small from the whole, but cannot be ignored.

FIG. 6B shows the state of the filament when it is half cut, and FIG. 6B shows the state of the filament when normal. In addition, the lamp current, lamp voltage, and
The variation characteristics of the illuminance (illuminance measured at the tip of the light guide that guides the lamp light) are shown in FIG. 7 (a), (b),
(C). However, the values shown in FIG. 7 are examples,
Since the method of fusing the filaments is different, the rate of change in lamp current, lamp voltage, and illuminance after the lamp is half cut also has different values.

As described above, the fusing phenomenon of the filament during the life of the lamp may be a half-cut state or a complete fusing. In most cases, it will be in a half-cut state, but in some cases it will be completely melted without going through the half-cut state, so two detection methods are required.

Here, the detection of the half-cut state will be taken up first.

FIG. 8 shows the lamp current with respect to the lamp voltage of a normal lamp and a lamp in a half-cut state. As can be seen from this figure, in the case of the lamp in the half cut state, the impedance of the filament is lowered, so that the lamp current becomes larger than that of the normal lamp even if the same voltage is applied.

Therefore, conventionally, focusing on this lamp current difference, by detecting the lamp current, the filament is not half-cut,
Some short circuits were detected. That is, as shown in FIG. 2, a constant current value a (eg, 9
When A) is set and the current flowing through the lamp exceeds the set value a, it is assumed that the filament is partially short-circuited.

However, in the case of the method of dimming by the voltage adjustment type dimming function in order to control the amount of emitted light, because the current of a constant current value (9A) or more flows, like the set value a in FIG. When attempting to detect a partial short circuit of the filament, the lamp current also decreases when the lamp voltage is low. Therefore, when the lamp voltage is higher than the intersection point c between the filament partial short circuit lamp current b and the set value a, the detection is performed. However, when the lamp voltage is lower than the intersection point c, the lamp current is always lower than the set value a, so that there is a drawback that a partial short circuit cannot be detected.

Next, let us take a look at lamp burnout detection in the case of complete blowout.

Conventionally, when the filament is completely melted, the impedance becomes infinite and the current stops flowing.Therefore, the supply current of the lighting power supply that supplies power to the incandescent lamp is detected, and when this current becomes zero, the lamp I was trying to detect a break.

However, this conventional method has a drawback in that the lamp burnout cannot be detected when the lamp is not lit or when the voltage supplied to the lamp is lowered by dimming.

For example, in the case of a light source device for robot vision,
Power is not always supplied to the lamp from the power supply for lighting, and in order to extend the lamp life, if the robot returns to the standby position even when the robot is operating, the power supply should be turned off to turn it off. I have to.

Usually, in the light source device, in order to keep the reflected light from the subject constant regardless of the type of subject photographed by the camera,
The dimming control is performed to change the power supply voltage of the lamp according to the reflected light from the subject. Therefore, when the lamp voltage is high, there is no problem, but when the lamp voltage is low, the current supplied to the lamp is also low.

In this way, when the power is turned off or the voltage becomes low, there is a problem that the lamp is erroneously determined to be a lamp burnout by detecting the zero current, even though the conventional lamp does not burn out. .

[Problems to be Solved by the Invention] As described above, in the conventional lamp abnormality detection circuit, the set current for detecting the abnormal current due to the partial short circuit of the filament is set to a constant value set at the rated voltage, so that the dimming is performed. If the power supply voltage supplied to the incandescent lamp is lowered for
Since the partial short-circuit current also drops, it is difficult to detect this partial short-circuit when the voltage is lower than the rated voltage.

Further, as described above, in the conventional lamp burnout detection circuit that detects the lamp current of the lighting power supply and detects the lamp burnout when this detected current is zero, when the incandescent bulb is turned off, When the voltage supplied to the power supply voltage decreases due to the dimming and the lamp current becomes zero, it is also determined that the lamp is burnt out. Therefore, there is a drawback that the lamp burnout cannot be detected under these conditions.

In addition, in the conventional type, partial short-circuit detection and complete fusing detection are performed independently of each other, and those that detect partial short-circuit lack detection of complete fusing. Some of the things that were done lacked short-circuit detection, so lamp failure could not be detected 100% completely.

Further, in the conventional apparatus, even if the lamp abnormality can be detected, the irradiation cannot be continued until the incandescent light bulb is replaced, so that the photographing is interrupted during that time.

The object of the present invention is to eliminate the above-mentioned drawbacks of the prior art, and to detect an abnormality due to a partial short circuit or complete fusing of the filament even when the supply voltage of the incandescent light bulb is low or when the lamp is turned off, and without error. SUMMARY OF THE INVENTION It is an object of the present invention to provide a lamp switching device capable of detecting a lamp abnormality without omission and automatically switching to a normal lamp when a lamp abnormality is detected.

Another object of the present invention is to provide, in addition to the above objects, a lamp switching device in which the illuminance does not drop even when the lamp is switched at the time of an abnormality.

[Means for Solving the Problems] In order to achieve the above object, in the lamp switching device according to the present invention, an output voltage of a lighting power supply for supplying power to an incandescent light bulb using a filament such as a halogen lamp has an output voltage of an incandescent light bulb. In the light source device that changes in order to vary the power supply and intermittently supplies power to the incandescent light bulb, two incandescent light bulbs, one of which is the irradiation side and the other of which is the standby side, and the incandescent light bulbs, which extend from the incandescent light bulb respectively The cores of the bundled optical fibers are evenly mixed, and a light guide that guides the light of the incandescent lamp on the irradiation side or the incandescent lamp on the standby side equally to the subject, and a minute current for detecting the fusing of the filament is supplied to the lighting power supply. It detects the lamp burnout detection power supply that is superimposed on the supply current and supplies it to the incandescent light bulb, and the current that is supplied from this lamp burnout detection power supply to the incandescent light bulb. The zero current detection circuit that outputs an abnormal signal when it becomes low, and the current value that matches the characteristics of the abnormal current that flows in the incandescent light bulb in proportion to the power supply voltage when the filament is partially short-circuited before the filament is blown are preset. , The abnormal current detection circuit that compares this set current with the detected current flowing through the incandescent light bulb and outputs an abnormal signal when the detected current becomes larger than the set current, and the abnormal current detection circuit or zero current detection circuit It is provided with a switching means for switching the power supply of the lighting power source from the irradiation side incandescent lamp to the standby side incandescent lamp by the signal output.

Further, the lamp switching device in the present invention, one of the irradiation side,
Two incandescent lamps using a filament such as a halogen lamp with the other as the standby side, and the cores of the optical fibers extending from each of these incandescent lamps and bundled in the middle are evenly mixed, and the irradiation side incandescent lamp or A light guide that guides the light of the incandescent light bulb on the standby side to the subject equally, a light-shielding unit that shields the light of the incandescent light bulb, and a dividing unit that divides the dimming level for changing the light amount of the incandescent light bulb into two types, high and low. , The irradiation side incandescent lamp and the standby side incandescent lamp are supplied with the power supply voltage according to the dimming level respectively, the irradiation side lighting power source and the standby side lighting power source, and the minute current for detecting the fusing of the filament, the lighting power source. The power supply for lamp burnout detection that is superimposed on the current supplied to the incandescent light bulb and the current that is supplied from this power supply for lamp burnout detection to the incandescent light bulb are detected, and the current is reduced to zero. If a zero current detection circuit that outputs an abnormal signal when there is a short circuit occurs and a set current value that matches the characteristics of the abnormal current that flows in the incandescent light bulb in proportion to the power supply voltage when the filament is partially short-circuited before the filament is blown. An abnormal current detection circuit that outputs an abnormal signal when the detected current exceeds the set current as compared with the detected current flowing through the incandescent light bulb, and when normal, the side with the higher dimming level output from the dividing means is the irradiation side. To the power source for lighting, while giving the lower one to the power source for lighting on the standby side, cancel the light blocking of the incandescent lamp on the irradiation side by the light shielding means, and shield the light of the incandescent lamp on the standby side.
When abnormal, the higher dimming level is supplied to the standby side lighting power source, the lower one is supplied to the irradiation side lighting power source, and the light blocking of the standby side incandescent light bulb is released to control the light of the irradiation side incandescent light bulb. It is also possible to prepare for and.

[Operation] In the first lamp switching device of the present invention, when the output voltage of the lighting power source is lowered to reduce the light amount of the incandescent light bulb, a set current for detecting a partial short circuit of the filament is generated accordingly. Also decreases. Then, since the lowered set current is compared with the detected current, the abnormal signal can be output from the abnormal current detection circuit even when the detected current has a low value. Therefore, even when the power supply voltage is lower than the rated voltage, it is not difficult to detect a partial short circuit.

In addition, a current for detection is always supplied from the power supply for lamp burnout detection to the incandescent light bulb, separately from the power supply for lighting. For this reason,
The current for detection always keeps a constant value even when the current is not supplied from the power source for lighting and the light source is turned off or when the output voltage of the power source for lighting is dimmed. Therefore, the detection current becomes zero only when the filament is blown, and the lamp burnout signal is output from the current detection circuit. Therefore, the filament blowout is detected even when the filament is extinguished or at a low voltage.

In this way, no matter what the state of the light source device,
Not only a partial short circuit of the filament but also the complete melting of the filament is detected.

Further, when an abnormal current flows in the incandescent lamp on the irradiation side or when a minute current for detecting lamp burnout stops flowing, the current detection circuit detects this and an abnormal signal is output. Then, due to this abnormal signal, the switching means switches the power supply of the lighting power supply from the irradiation side incandescent bulb to the standby side incandescent bulb, so that the standby side incandescent bulb is automatically turned on. Therefore,
Continuous irradiation can be done without waiting for the incandescent bulb replacement work.

Further, even if the incandescent light bulb is switched, since the fiber core wires are evenly mixed, the amount of light emitted to the subject by any of the incandescent light bulbs is the same, and the illuminance of the subject does not change due to the light bulb switching.

Further, in the second lamp switching device of the present invention, the lower dimming level is applied to the standby side lighting power source from the dividing means during normal operation. For this reason, a low supply voltage is supplied to the incandescent lamp on the standby side, and the incandescent lamp is preheated and lit with a lower illuminance than originally. At this time, the light blocking means of the standby-side incandescent light bulb is closed to shield the light, so that the light of the standby-side incandescent light bulb does not leak to the outside.

At the time of abnormality, the control means operates by the abnormality signal output of the current detection circuit, and the irradiation side incandescent lamp whose illuminance has changed due to the abnormality is shielded by the irradiation side light shielding means. At the same time, the dividing means adds the higher dimming level to the standby side lighting power supply to which the lower dimming level was added until then, so that the standby side incandescent lamp rapidly reaches its original brightness. Since the light blocking means on the standby side releases the light blocking, the illuminance does not drop when the light source is automatically switched.

[Embodiment] An embodiment of the present invention will be described below with reference to FIGS. 1 to 3.

FIG. 1 is a configuration diagram showing an embodiment of the present invention, and particularly illustrates a two-lamp type fiber light source device constituting a visual part mounted on a robot.

Reference numeral 1 denotes a lamp house attached to the movable part of the robot, and two halogen lamps with mirrors 2 and 3 with uniform characteristics are provided inside. One is the standby side or the standby side, and the other is the irradiation side or the main side.

A light guide 4 using an optical fiber for illuminating a subject 6 located at a position away from the lamp house 1 is provided on the front surface of the lamp house 1 facing the halogen lamps 2 and 3. The base end is divided into two pieces and merges into one piece in the middle, and the tip end extends to a position near the camera, for example, the CCD camera 5. This light guide 4 is a halogen lamp 2
Even if light is emitted from either of 3 or 3, the subject 6 has the same illuminance.
The fiber core wires forming the branched portion are bundled so that they are evenly mixed at least at the tip of the merged portion. The light guide 4 is used because infrared rays are cut and the optical path is flexible,
In addition, the tip shape can be any shape, whether ring-shaped or line-shaped.

On the rear surface of the lamp house 1, power lines for the halogen lamps 2 and 3 are drawn out and connected to a lamp lighting power source 7 attached to a fixed portion. The power supply 7 uses a switching regulator having an overcurrent prevention function here, but may be a series regulator as long as it has an overcurrent prevention function. The overcurrent prevention function is provided to protect its own circuit element.

The light receiver 9 such as the photodiode PD generates a voltage proportional to the intensity of the light quantity reflected from the subject 6, and this voltage is applied to the lamp voltage control analog voltage generation circuit 8. Here, the lamp voltage control analog voltage generation circuit 8 controls the output voltage of the lamp lighting power supply 7 in the form of an analog voltage dimming command for keeping the reflected light of the subject 6 constant regardless of the type of the subject 6. For analog input terminal. As a result, the CCD camera 5 can always capture a fixed amount of reflected light.

The negative output line of the lamp lighting power supply 7 is commonly connected to one terminal of each halogen lamp 2 and 3, and the positive output line is connected to either the other terminal of the lamp 2 or 3 via the relay RY. It is designed to be connected as an alternative.

The relay RY is controlled by an abnormal current detection circuit 18 that detects a partial abnormality of the filament, or an OR circuit 31 that outputs an output when an abnormal signal is detected by the zero current detection circuit 21.

The abnormal current detection circuit 18 compares the detection voltage proportional to the lamp current extracted from the reference voltage generation circuit 10 and the resistor R1 inserted in the negative output line with the reference voltage output from the reference voltage generation circuit 10. And a comparator circuit 11 for outputting an abnormal signal. As shown in FIG. 2, the reference voltage generating circuit 10 generates a reference voltage proportional to the current set value d proportional to the lamp supply voltage which is the output of the lamp lighting power supply 7. The variable current setting value d, which is not a constant value, is set so as to take a value according to the characteristic of the abnormal current intermediate between the lamp current b when the filament is partially short-circuited and the lamp current e when the lamp is normal. . This is because the partially short-circuited lamp electrode b and the normal lamp current e that can be known in advance are average values, and therefore taking into account actual variations, an intermediate value between these values is preferable as the set value. The reference voltage generator 10 is composed of, for example, a known adder or function generator.

Thus, the comparison circuit 11 compares the lamp detection current with the set current, and when the detected current becomes larger than the set current, outputs the lamp half-breakage abnormality signal to the switching circuit 19 via the OR circuit 31.

The zero current detection circuit 21 detects the current supplied to the lamp 2 or 3 from the lamp burnout detection power supply 20 provided separately from the lamp lighting power supply 7. Power supply for lamp burnout detection
Reference numeral 20 denotes a power supply for supplying a minute current to the lamp 2 or 3 for detecting the filament blowout of the lamp 2 or 3. The power source 20 is a constant voltage source in the illustrated example, but may be a constant current source. The minute current is passed in order to prevent the lamp from lighting. In order to supply the lamp 2 or 3 with the minute current superposed on the supplied current without flowing back to the lighting power supply 7, the lamp burnout detection power supply 20 outputs its negative output line to the lamp lighting power supply 7. While being commonly connected to the negative output line, the positive output line led out via the diode D2 is commonly connected to the positive output line of the lighting power source 7 also led out via the diode D1. That is, the cathodes of the diodes D1 and D2 are connected in common so that the currents of the two power supplies 7 and 20 do not flow back to each other but are superposed and supplied to the lamps 2 and 3.

The zero current detection circuit 21 detects a detection voltage proportional to a minute current extracted from both ends of the resistor R2 inserted in the positive output line of the lamp burnout detection power supply 20, and the detection voltage is zero, that is, the current is zero. At this time, the lamp burnout abnormality signal is output to the switching circuit 19 via the OR circuit 31. If the lamp burnout detection power source 20 is a constant current source, the zero current detection circuit
21 may also be a voltage detection circuit that detects an abnormally high voltage generated in the constant current source by opening the circuit.

The switching circuit 19 is composed of a T-type flip-flop 12 and a relay RY, and is connected to the OR circuit 31 by an abnormal signal.
The type flip-flop 12 is inverted, the relay RY is turned on, and the positive output line is switched from the irradiation side lamp 3 to the standby side lamp 2. At the same time, the alarm lamp 13 attached to the lamp lighting power supply 7 is turned on by an abnormal signal. Note that an alarm device may sound instead of the alarm lamp.

Next, the operation of the above configuration will be described.

Initially, the relay RY is turned off and switched to the irradiation side lamp 3 side. Therefore, the lamp 3 supplied with power from the lamp lighting power source 7 serves as an irradiation light source, and the light is guided to the light guide 4 to illuminate the subject 6 from the tip of the light guide.

Here, when the filament of the lamp 3 has reached the end of its life, the filament is partially short-circuited, and the lamp current flowing through the lamp 3 becomes large, and exceeds the set current converted and output from the reference voltage generation circuit 10, the comparison circuit An abnormal signal “H” is output from 11 to the OR circuit 31. Then, the T-type flip-flop 12 is inverted and becomes "H", and the relay RY is turned on. Therefore, power is automatically supplied from the irradiation side lamp 3 to the standby side lamp 2 which had been supplied with power from the lamp lighting power supply 7 until then. And the standby-side lamp 2 becomes a new light source. At the same time, the warning lamp 13 is turned on, so that the worker recognizes the lamp abnormality. Therefore, the worker uses the time during which the robot is stopped to replace the abnormal halogen lamp 3 with a new lamp.

On the contrary, when the auxiliary lamp 2 which has begun to be supplied with power becomes abnormal, the comparator circuit 11 again outputs an abnormal signal, and this time the T type flip-flop 12 is set to "L", so the relay RY is turned off. Therefore, the power supply is switched from the lamp 2 to the newly replaced lamp 3.

On the other hand, under normal conditions where the lamp 3 serves as the irradiation light source and the lamp 2 serves as the standby light source, the voltage of the lamp lighting power supply 7 is set to V1,
Assuming that the voltage of the lamp burnout detection power supply 20 is V2, if V2> V1, a minute current I ₂ shown by the following equation flows in the positive output line of the lamp burnout detection power supply 20.

I ₂ = {V ₂ − (V ₁ −VD ₁ ) −VD 2} / R where VD ₁ and VD 2 are the forward voltage of the diodes D 1 and D 2,
For the current detection resistor R2, select a resistance value that is considerably higher than the impedance of the lamp filament.

Here, when the filament of the lamp 3 has reached the end of its life and the filament is completely melted, the power source for detecting lamp burnout is generated.
Since the impedance of the cathode side of the diode D2 inserted on the 20 side becomes almost infinite, regardless of the mode state (light off or low voltage state) of the lamp lighting power supply 7, the lamp burnout detection power supply 20 The lamp current flowing in the lamp 3 at the indicated value becomes I ₂ ≈0. As a result, the voltage drop across the resistor R2 becomes zero, so that the zero current detection circuit 21 outputs the lamp burnout abnormality signal “H” to the OR circuit 31. Then, after that, the same operation as in the case of the filament short circuit detection described above is performed, the lamp is automatically switched, and the alarm lamp is turned on.

As described above, in this embodiment, the current setting value d set in the comparison circuit 11 is changed in proportion to the lamp supply voltage as shown in FIG. Even if it is lowered, it is possible to detect a partial short circuit phenomenon of the filament. That is, in FIG. 2, detection is possible if the lamp voltage is higher than the intersection f of the filament partial short-circuit lamp current b and the variable current setting value d. Since it is significantly closer to the low voltage side (5 V or less) than the intersection point c, the partial short circuit abnormality can be reliably detected even at the low voltage. The lamp voltage is 5
Since dimming smaller than the bolt does not provide illuminance, it is out of the practical range and is not a problem.

Further, a lamp burnout detection power source 20 is provided outside the lamp lighting power source 7 so that a minute current for detection is supplied to the lamps 2 and 3 independently of the lamp current of the lamp lighting power source 7. Therefore, not only during lighting, but also during lighting, when the robot-equipped light source device is stopped during operation of the robot and does not receive power from the lamp lighting power supply 7, the lamp burnout detection current is supplied to the lamp. You can continue to run.
Even when the power supply voltage of the lamp lighting power supply 7 is lowered by the light control and the value of the current supplied from the lamp lighting power supply 7 to the lamp 2 or 3 is reduced, the lamp burnout is similarly detected. It is possible to continue passing a current as large as possible.

Therefore, by always detecting the current of the lamp burnout detection power source 20 by the zero current detection circuit 21, it is possible to reliably detect the lamp burnout without error.

In addition, since both power supplies 7 and 20 are connected so that the diodes D1 and D2 have a common cathode and do not flow backwards from each other, the current supplied from the lamp burnout detection power supply 20 to the lamp 2 or 3 is a minute current. There is no disturbance of control and no inconvenience of lighting due to the detected current.

As described above, according to the present embodiment, it is possible to detect the lamp burnout at the same time without stopping at the lamp half burnout.
Since it is possible to detect 100% of lamp abnormalities and automatically switch to a normal lamp when a lamp abnormality occurs, it is possible to effectively avoid interruption of shooting due to a lamp abnormality.

By the way, in the above-mentioned two-lamp type fiber light source that is switched to the lamp on the standby side when the lamp on the irradiation side has reached the end of life, the lamp on the standby side, which has not been energized at all, becomes a new light source. It takes time and the illuminance drops temporarily. FIG. 3 shows another embodiment in which the drop in illuminance at the time of switching is eliminated.

Two (NO1, NO2) halogen lamps in lamp house 1
Shutters 24 and 14 which are light-shielding means for opening and closing the optical paths to the branch light guide 4 are provided on the front surfaces of 2 and 3, respectively. These shutters 24, 14 are controlled to be opened and closed by shutter drive rotary solenoids 26, 16 which are operated by applying a voltage from a rotary solenoid drive power source 23. The output voltage of the rotary solenoid driving power source 23 is selectively applied to the shutter driving rotary solenoid 26 or 16 by the relay RY2. When the relay RY2 is off, the power supply voltage is the NO2 side shutter drive rotary solenoid 26 as shown in the example.
, The shutter 24 is opened to guide the light of the NO2 lamp 2 to the light guide 4, and the shutter 14 on the NO1 side is closed to block the light of the NO1 lamp 3. When the relay RY2 is on, the light from the NO1 lamp 3 is passed through and the NO2 lamp 2
The light is blocked.

The shutter is not limited to the mechanical one as described above, and may be an optical one such as an optical switch.

The lamps 2 and 3 are separately supplied with electric power by the NO2 lamp lighting power supply 27 and the NO1 lamp lighting power supply 17, and the output lines for supplying those powers are described in FIG. An NO2 current detection circuit 25 and an NO1 current detection circuit 15 each composed of an abnormal current detection circuit 18 and a zero current detection circuit 21 are interposed. Further, a NO2 lamp burnout detection power supply 42 and a NO1 lamp burnout detection power supply 32 are connected to the NO2 current detection circuit 25 and the NO1 current detection circuit 15, respectively.

An output signal of the lamp voltage control analog voltage generation circuit 8 for dimming is applied to the output voltage control analog input terminals of the respective lighting power supplies 27 and 17 on the NO2 side and the NO1 side. This output signal is divided by the voltage generating circuit 8 and the lighting power sources 27 and 17 so that one of the lamps is lit at a lower voltage than the other lamp so that the lamp is on the standby side. Circuit 30
2 types are made by either, and either one is NO2 side or NO1
In addition to the lighting power sources 27 and 17 on the side, the type of signal can be switched by the relay RY1 so that either lamp can be the irradiation side or the standby side. Here, the voltage dividing circuit 30 supplies the analog voltage for controlling the lamp voltage to 10
Although it is divided into 0% and 90% and taken out, the partial pressure ratio of 90% is not limited to this. To turn on the standby lamp with a lower voltage than the irradiation lamp,
This is to extend the life of the lamp on the standby side. Generally, if the voltage applied to the lamp is reduced by 10%, the life is extended three times.

Further, when the relay RY1 is turned off, a 100% analog voltage is applied to the lamp lighting power supply 27 of NO2 and a 90% analog voltage is applied to the lamp lighting power supply 17 of NO1 as shown in the illustrated example.
When the relay RY1 is turned on, 90% voltage is applied to the NO2 lighting power source 27 and 100% voltage is applied to the NO1 lighting power source 17 on the contrary.

Control means for controlling ON / OFF of the relays RY1 and RY2 described above
40 comprises a lighting lamp discrimination circuit 28 and a switching circuit 22. The lighting discrimination circuit 28 determines from the abnormal signal output from the current detection circuit 25 or 15 which of NO1 and NO2 lamps has become abnormal. Further, based on the determination result of the lighting discrimination circuit 28, the switching circuit 22 outputs a relay output that changes the NO1 to the standby side and changes the NO2 to the irradiation side if the lamp 3 of the NO1 being irradiated is abnormal, and vice versa. If the NO2 lamp 2 is abnormal, the relay output that changes NO2 to the standby side and changes NO1 to the irradiation side is output.

In the illustrated example, the switching circuit 22 is composed of an RS flip-flop composed of NAND-C and NAND-D. The lighting lamp discrimination circuit 28 operates when the output of the RS flip-flop is "L".
NAND-A that inverts the abnormal signal "H" of the NO2 current detection circuit 25 to the set input terminal S of the RS flip-flop and inputs it
And NAND-B for inverting and inputting the abnormal signal "H" of the NO1 current detection circuit 15 to the reset input terminal R of the RS flip-flop when the output of the RS flip-flop is "H". However, these circuits are examples and are not limited to these.

Next, the operation of the above configuration will be described.

When the relays RY1 and RY2 are turned on, the shutter 14 on the NO1 side is opened, and the NO1 lamp lighting power supply 17 is dimming-controlled by the 100% voltage signal of the lamp voltage control analog voltage generation circuit 8. As a result, the NO1 lamp 3 is turned on with the original brightness, and the light is emitted to the external subject 6 through the two-branch light guide 4. At this time, the analog input of the power supply 27 for the NO2 lamp is about the analog voltage for lamp voltage control.
Since 90% voltage is applied, NO2 lamp 2 is NO1 lamp 3
It is lit at a lower voltage (90%). Moreover, since the NO2 shutter 24 is closed, the light of the NO2 lamp 2 does not go outside.

In the above-mentioned state, when the NO1 lamp 3 has reached the end of its life (partial short circuit or complete melting of the filament), the current detection circuit 15 on the NO1 side operates and the abnormal signal “H” is output. Since the NAND-B output of the discrimination circuit 28 becomes "L",
The output of NAND-C of switching circuit 22 is inverted to "L" and relay RY
1, RY2 turns off. Therefore, the voltage of the rotary solenoid drive power supply 23 is applied from the NO1 side to the shutter drive rotary solenoid 26 on the NO2 side, and the NO that has been closed until then.
The shutter 24 of 2 opens. Further, the lighting power supply 27 for NO2, which had been driven by 90% voltage until then, operates at full power with the 100% voltage signal of the lamp voltage control analog voltage generation circuit 8 being applied, and the light of the NO2 lamp 2 is 2%. It is irradiated to the outside through the branch light guide 4.

At this time, about 90% of the analog voltage for lamp voltage control is applied to the analog input of the power supply 17 for the NO1 lamp. If the abnormality of NO1 lamp 3 becomes abnormal and the filament is completely melted, there is no problem, but if the filament is partially short-circuited, NO1 lamp 3 will light up at a low voltage that dropped from 100% to 90%, affecting the subject. Will be given. But,
Since the shutter 14 that has been open up to now is closed by releasing the drive of the shutter driving rotary solenoid 16, the light of the NO1 lamp 3 with reduced illuminance does not go outside. Therefore,
The illuminance of the subject 6 emitted through the light guide 4 is
Correct illuminance is maintained. After replacing the NO1 lamp 3 with a new one, it will be on standby at a low voltage.

Similarly, when the NO2 lamp 2 becomes abnormal, the NO1 lamp 3 is switched through the above process.

During the irradiation of the NO1 lamp 3, when the pre-energized NO2 becomes abnormal and the current detection circuit 25 operates, the output of the NAND-B of the lighting lamp discrimination circuit 28, which is the main switching unit for NO2, is output. Since it does not become "L", it does not switch to NO2. This also applies to the irradiation of the NO2 lamp 2.

As described above, in the above embodiment, the two-lamp type lamps 2, 3
Since a low voltage is constantly applied to the standby side of the lamp to cause residual heat, even if the light source switches to the standby side due to a short circuit or complete melting of the filament on the irradiation side and the light source switches to the standby side, Since the lamp can quickly rise to the original illuminance, the illuminance does not drop when switching. Therefore, there are no shooting problems associated with reduced illuminance,
The visual function of the robot can be maintained. Also, when the lamp on the standby side is on, the shutter is closed to block the light, and the light is prevented from overlapping the light from the lamp on the irradiation side. Is never high.

Further, since 90% voltage is applied to the lamp on the standby side by the voltage dividing circuit 30, the lamp life on the standby side can be extended nearly three times.

[Effects of the Invention] The present invention has the following effects.

In the lamp switching device according to the first aspect of the present invention, since the abnormality of both the partial short circuit and the complete fusing of the filament is detected, the lamp abnormality can be detected without omission, and the supply voltage of the incandescent lamp is low. In this case, even if the lamp is turned off, the setting current of the abnormal current detection circuit is made variable, and the power supply for detecting lamp burnout is provided separately from the power supply for lighting so that these effects are not affected. Therefore, the abnormality can be detected without error. Moreover, when the abnormal signal is output, the power supply is switched from the incandescent light bulb on the irradiation side to the incandescent light bulb on the standby side, so that continuous irradiation can be performed without exchanging the incandescent light bulb at the time of abnormality.

In the lamp switching device according to claim 2, the standby-side incandescent light bulb is pre-energized, and when abnormality occurs in the irradiation-side incandescent light bulb, it is switched to the main energization to shield the standby-side incandescent light bulb from light-shielding means. Since the above is canceled, it is possible to prevent the illuminance from dropping when the lamps are switched, without affecting the illuminance in the normal state.

[Brief description of drawings]

FIG. 1 is a configuration diagram of a lamp switching device showing an embodiment of the present invention, and FIG. 2 is a voltage-current characteristic diagram comparing set currents of a conventional example for detecting a lamp filament half-break and an example of the present invention. FIG. 3 is a configuration diagram of a lamp switching device showing another embodiment of the present invention, FIG. 4 is a current characteristic diagram when a halogen lamp is blown, and FIG. 5 is a current drooping characteristic diagram of a power source having an overcurrent prevention function. Fig. 6 is a filament comparison diagram when normal and half cut,
FIG. 7 is a variation characteristic diagram when the filament is half cut, and FIG. 8 is a voltage-current characteristic diagram of the halogen lamp. In the figure, 2 is a standby side halogen lamp (incandescent light bulb), 3 is an irradiation side halogen lamp (incandescent light bulb), 6 is an object, 7 is a power source for lighting the lamp, and 8 is a lamp voltage control analog as a dimming level generator. Voltage generation circuit, 14 is a shutter on the irradiation side, 15 is a current detection circuit on the irradiation side, 17 is a power source for lighting on the irradiation side, 18 is an abnormal current detection circuit, 19 is a switching circuit, 24 is a shutter on the standby side, 20 is A lamp burnout detection power supply, 21 is a zero current detection circuit, 25 is a standby side current detection circuit, 27 is a standby side lighting power supply, 30 is a voltage dividing circuit as dividing means, and 40 is a control circuit.

Claims (2)

[Claims] 1. A light source device for changing the output voltage of a lighting power source for supplying power to an incandescent lamp using a filament such as a halogen lamp to change the light amount of the incandescent lamp, and intermittently supplying power to the incandescent lamp. In the above, two incandescent lamps, one of which is on the irradiation side and the other of which is on the standby side, and the cores of the optical fibers which are respectively extended from these incandescent lamps and bundled in the middle are evenly mixed, A light guide that guides the light from the incandescent lamp on the standby side equally to the subject, a lamp burnout detection power supply that superimposes a minute current for detecting the fusing of the filament on the supply current of the lighting power supply, and this lamp A zero current detection circuit that detects the current supplied to the incandescent light bulb from the power supply for disconnection detection and outputs an abnormal signal when the current reaches zero When a part of the generated filament is partially short-circuited, a current value is set in advance in proportion to the power supply voltage according to the characteristics of the abnormal current flowing through the incandescent light bulb, and the detected current is set by comparing this set current with the detection current flowing through the incandescent light bulb An abnormal current detection circuit that outputs an abnormal signal when it becomes larger than the current, and the abnormal signal output of the abnormal current detection circuit or the zero current detection circuit causes the irradiation side incandescent light bulb to supply power to the standby power supply A lamp switching device, comprising: switching means for switching. 2. Two incandescent lamps using filaments such as halogen lamps, one of which is on the irradiation side and the other of which is on the standby side, and the cores of the optical fibers that extend from these incandescent lamps and are bundled in the middle. A light guide that guides the light of the incandescent lamp on the irradiation side or the incandescent lamp on the standby side equally to the subject, a light-shielding unit that shields the light of the incandescent lamp, and a dividing unit that divides the dimming level into two types, high and low. And the irradiation side incandescent lamp and the standby side incandescent lamp are supplied with the power supply voltage according to the dimming level respectively, the irradiation side lighting power supply and the standby side lighting power supply, and the minute current for detecting the fusing of the filament. It detects the lamp burnout detection power supply that superimposes on the power supply current and supplies it to the incandescent light bulb, and the current that is supplied from this lamp burnout detection power supply to the incandescent light bulb, and that current becomes zero. In case of a short circuit of the filament current that occurs before the filament is blown, the current value that matches the characteristics of the abnormal current flowing through the incandescent light bulb in proportion to the power supply voltage is used as the set current. An abnormal current detection circuit that outputs an abnormal signal when the detected current exceeds the set current as compared with the detected current flowing through the incandescent light bulb, and when normal, the one with the higher dimming level output from the dividing means is the irradiation side. As for the power source for lighting, the lower one is supplied to the power source for lighting on the standby side, the light blocking of the light bulb on the irradiation side by the light blocking means is released, and the light on the standby light bulb on the standby side is blocked. The higher one is supplied to the standby side lighting power source, the lower one is supplied to the irradiation side lighting power source, and the control means for releasing the light blocking of the standby side incandescent light bulb and blocking the light of the irradiation side incandescent light bulb is provided. And run Switching device.