JP2594291B2 - Illumination light source device for observation of optical equipment - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an illumination light source device for observing optical devices such as a microscope and a fundus camera.

[Conventional technology]

There are various types of light bulbs used for the illumination light source device for observation of optical equipment, and among them, there are light bulbs having the same shape and different loads. For this reason, it is easy for the user to mistakenly mount a bulb with a load higher than the rated load, in which case an overcurrent flows in the power supply circuit, and the power supply circuit using the transformer increases heat generation and may cause a fire accident or the like. Occurs.
Conventionally, in order to prevent the danger caused by heating of the transformer, a thermal fuse is conventionally provided inside the transformer, and when the temperature of the transformer exceeds a certain temperature, the thermal fuse is blown to stop heat generation. Was.

In addition, an overcurrent may flow through the power supply circuit due to fluctuations in the primary voltage or the like. In such a case, conventionally, the terminal voltage of the electric bulb is detected and the voltage monitor display element is turned on and off.

[Problems to be solved by the invention]

However, in the former case of the above conventional example, once a light bulb having a rated load or more is mistakenly attached to the light source device, the user does not notice the misuse until the thermal fuse inside the transformer of the power supply circuit is blown. When the user notices that the thermal fuse has already blown, it is difficult for the user to restore the function of the light source device by himself, and it is necessary to replace the thermal fuse or the transformer to restore the function. As a result, there is a problem that the user suffers a great deal of trouble after all. Also, in the latter case of the above conventional example, when an overcurrent does flow, an abnormality is notified by blinking of the voltage monitor display element. Therefore, there is a possibility that the use may be continued without noticing the notification.

The present invention has been made in view of the above problems, and when an overcurrent flows in a power supply circuit due to an incorrect use of a light bulb or a fluctuation of a primary power supply voltage, the function of a light source device is maintained and an abnormality is reliably notified to a user. It is an object of the present invention to provide an illumination light source device for observation of an optical device which is obtained.

[Means and actions for solving the problems]

An illumination light source device for observation of an optical apparatus according to the present invention includes a light source, a power supply circuit for supplying power to the light source, a current detection circuit for detecting a current flowing through the light source, and a current value detected by the current detection circuit. An overcurrent signal is output when the current value becomes equal to or more than a preset upper limit value to stop the power supply of the power supply circuit, and the overcurrent signal is stopped when the current value becomes equal to or less than the preset lower limit value. An on / off control circuit for restarting the power supply of the power supply circuit, wherein an abnormality is notified by blinking of the light source. Furthermore, a sound element for abnormality notification which operates by an overcurrent signal from the on / off control circuit is added.

 These points will be described in more detail.

FIG. 1 is a conceptual diagram of the present invention, in which electric power controlled by a power supply circuit 1 is supplied to a light bulb 2 and at this time,
A current flows through a current detection circuit 3 provided between the power supply and the light bulb 2 to generate an output voltage. Next, the output voltage of the current detection circuit 3 is compared with a reference voltage value (upper limit value) set in advance by the on / off control circuit 4, and if the output voltage is equal to or less than the reference voltage value (upper limit value), the overcurrent signal is output from the circuit 4. No, power supply circuit 1
Works fine. Note that the reference voltage value is the power supply circuit 1
Are the same as the output voltage value of the current detection circuit 3 when the maximum allowable current value (upper limit value) is output.

By the way, the mounting of the bulb 2 having the rated load or more or the power supply circuit 1
When a current equal to or greater than the maximum allowable current value flows through the power supply circuit 1 due to fluctuations in the primary power supply voltage supplied to the power supply circuit, the output voltage of the current detection circuit 3 becomes equal to or higher than the reference voltage value of the on / off control circuit 4,
The circuit 4 immediately outputs an overcurrent signal to stop the power supply of the bulb 2. Thereafter, when the current flowing through the bulb 2 decreases and the output voltage of the current detection circuit 3 becomes lower than a reference voltage value (lower limit value) preset by the on / off control circuit,
The circuit 4 immediately stops the overcurrent signal and the power supply of the power supply circuit 1 is restarted. In this manner, the stop and restart of the power supply of the power supply circuit 1 are repeated, so that the power supply circuit 1
Of the light source device is maintained within the allowable range, the function of the light source device is maintained, and the abnormality is reliably notified to the user by the flashing of the bulb 2 itself.

Further, if a sound-generating element 5 operated by an overcurrent signal from the on / off control circuit 4 is added, the abnormality can be more reliably notified to the user.

〔Example〕

Hereinafter, the present invention will be described in detail based on the illustrated embodiments. FIG. 2 is a circuit diagram of a first embodiment of the light source device according to the present invention, and FIG. 3 is a block diagram of a power supply circuit of the above embodiment.

The power supply circuit 1 is a phase control type dimming circuit, and as shown in FIG. 3, a transformer 6 for generating a secondary voltage, a full-wave rectifier circuit 7, a time constant setting circuit 8, and a triac trigger circuit 9
And a switching circuit 10 in order, a stabilizing circuit 11 is connected to both the full-wave rectifier circuit 7 and the time constant setting circuit 8, and a dimming volume 12 is connected to the time constant setting circuit 8. It is. The current detection circuit 3 includes a current detection element 13 for detecting a current A flowing from the power supply circuit 1 to the electric bulb 2, a load resistor 14 for generating an output voltage B by an output current of the current detection element 13, and an output thereof. Rectifier 15, a capacitor 17 for charging the output voltage C of the rectifier 15 via the charge resistor 16, and a discharge resistor 18 for discharging the charge accumulated in the capacitor 17 (this value is the value of the charge resistor 16). Much larger). Further, the on / off control circuit 4 compares the output voltage D at the connection point between the capacitor 17 and the discharge resistor 18 with the reference voltage E determined by the DC power supply 19 and the resistors 20 and 21 to determine the output voltage D as the reference voltage E The output voltage F is at the “L” level when
Is higher than the reference voltage E, the output voltage F becomes the "H" level, and the output voltage F is inputted to the trigger signal line of the time constant setting circuit 8 of the power supply circuit 1. ing. (FIG. 3).

 Next, the operation of the present embodiment will be described.

The output waveform of each part in the steady state is as shown in FIG. A current A flows from the power supply circuit 1 to the light bulb 2, and an output current of the current detection element 13 generates an output voltage B by the load resistor 14. The output voltage B is rectified by the rectifying element 15 and charged in the capacitor 17 via the charging resistor 16. At this time, since the value of the discharge resistor 18 is much larger than the value of the charge resistor 16, there is no influence when the discharge resistor 18 is charged. If the charging voltage D of the capacitor 17 is saturated and is smaller than the reference voltage E of the comparison / determination circuit 22, the output F of the comparison / determination circuit 22 remains at "L" level, and the power supply circuit 1 operates normally. continue.

Next, a case where an overcurrent flows through the power supply circuit 1 due to an incorrect use of the light bulb 2 and mounting of the light bulb 2 having a rated load or more or an abnormal fluctuation of the primary power supply voltage supplied to the power supply circuit 1 will be described. . The output waveform of each part at that time is as shown in FIG. As described above, the current A flows through the current detection element 13 and the output voltage B is generated by the load resistor 14.
The output voltage B is rectified by the rectifier 15 and charging of the capacitor 17 via the charging resistor 16 is started. Since an overcurrent flows in the power supply circuit 1, the charging voltage D of the capacitor 17 reaches _{VH of the} reference voltage E (point b in FIG. 5). Then, the output voltage F of the comparison determination circuit 22 is inverted to the “H” level, and the time constant setting circuit 8 of the power supply circuit 1 is stopped to stop the trigger signal to the triac trigger circuit 9, and to the light bulb 2. Stop the power supply. Comparison judgment circuit
When the output voltage F of the inverter 22 is inverted to the “H” level, the resistors 20, 2
Due to 1, the reference voltage E drops to _VL . And light bulb 2
When the supply of power to the capacitor 17 is stopped, the output voltage B of the current detecting element 13 is also lost, and the charging operation of the capacitor 17 is stopped. Then, the discharging is started by the capacitor 17 and the discharging resistor 18. When the discharge voltage D drops to the reference voltage _{VL that} has dropped with the inversion of the output of the comparison and judgment circuit 22, the output voltage F of the comparison and judgment circuit 22 is again inverted to the "L" level (point C in FIG. 5), and the power supply circuit 1 Power supply is started again. As a result, the fifth
The light bulb 2 is turned on between FIGS. A and b, turned off between bc and c,
During the period -d, the lamp is turned on again, and this operation is repeated, so that the light bulb 2 blinks, and the user is notified of the abnormality. Further, since the power supply from the power supply circuit 1 to the light bulb 2 is intermittent, the current value is kept within an allowable range, and damage to the circuit due to an overcurrent is prevented. Therefore, when the bulb 2 is erroneously mounted, normal use within the rated current can be performed again.

As described above, according to the present embodiment, the light bulb 2 itself is turned on and off as an abnormality notification method in which an overcurrent flows through the power supply circuit 1 due to misuse of the light bulb 2 or fluctuation of the primary power supply voltage of the power supply circuit 1. As a result, the use of the light source device becomes impossible, and the user can be reliably notified of the abnormality. Therefore, there is no fear that the user will continue to use without noticing. In addition, in the abnormal state, the damage of the light source device itself can be prevented, so that the function of the light source device can be restored immediately if the cause of the abnormal state is removed. Therefore, it does not take much effort to recover the function, and the trouble that the user suffers is small.

FIG. 6 shows a second embodiment, in which the current detection method and the judgment method are the same as those in the first embodiment, but as an abnormality notifying means, a comparison judgment is made as shown by a broken line in FIG. The sounding element 5 is connected to the output line of the circuit 22,
Operate according to an overcurrent signal from the comparison / determination circuit 22. Therefore, the abnormality is also notified by the warning sound, so that the user can be more reliably notified of the abnormality.

〔The invention's effect〕

As described above, the light source device according to the present invention can prevent loss of function of the light source device due to fusing of a fuse or the like when an overcurrent flows in a power supply circuit due to an incorrect use of a light bulb or fluctuation of a primary power supply voltage. This has an important advantage that the user can be reliably notified of an abnormality even when the specimen is observed for a long time.

[Brief description of the drawings]

1 is a conceptual diagram of the present invention, FIG. 2 is a circuit diagram of a first embodiment of an illumination light source device for observation of optical equipment according to the present invention, FIG. 3 is a power supply circuit and a block diagram of the first embodiment, FIG. 4 and 5
FIGS. 6A and 6B are diagrams showing output waveforms of respective parts in a steady state and an abnormal state in the first embodiment, respectively. FIG. 6 is a circuit diagram of the second embodiment. 1 power circuit 2 light bulb 3 current detection circuit 4
... On-off control circuit, 5 ... Sound generator, 6 ... Transformer, 7 ... Full-wave rectifier circuit, 8 ... Time constant setting circuit, 9 ...
... triac trigger circuit, 10 switching circuit, 11 stabilization circuit, 12 dimming volume control, 13 ...
Current detection element, 14… Load resistance, 15… Rectifier element, 16…
… Charge resistance, 17 …… Capacitor, 18 …… Discharge resistance, 19…
... DC power supply, 20, 21 ... resistor, 22 ... comparison judgment circuit.

Claims (1)

(57) [Claims] A light source; a power supply circuit for supplying power to the light source; a current detection circuit for detecting a current flowing through the light source; and a current value detected by the current detection circuit being equal to or greater than a predetermined upper limit value. When this happens, an overcurrent signal is output to stop the power supply to the power supply circuit, and when the current value falls below a preset lower limit, the overcurrent signal is stopped and the power supply to the power supply circuit is restarted. An illumination light source device for observation of an optical device, comprising: an on / off control circuit for performing an abnormality notification by blinking the light source.