JPH0193090A - Illumination light source device for observation of optical instruments - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a light source device for an observation system of an optical instrument such as a WU microscope or a fundus camera.

[Conventional technology]

There are a wide variety of light bulbs used in observation light source devices, and some of them have the same shape but different loads. Therefore, it is easy for the user to install a bulb with a load higher than the rated load due to user error, in which case an overcurrent will flow in the power supply circuit, and in the power supply circuit using a transformer, heat generation will increase, creating a danger such as a fire accident. occurs. In order to prevent this danger from overheating of the transformer, conventionally a temperature fuse was installed inside the transformer, and when the temperature of the transformer exceeded a certain temperature, the temperature fuse fused and stopped the heat generation. Ta.

In addition, overcurrent may flow in the power supply circuit due to fluctuations in the negative voltage, and in this case, conventionally, the terminal voltage of the light bulb was detected and the voltage monitoring display element was made to blink.

[Problem that the invention seeks to solve]

However, in the former case of the above-mentioned conventional examples, if a light bulb with a load higher than the rated load is accidentally attached to the light source device, the user will not notice the misuse until the temperature fuse inside the transformer of the power supply circuit blows out, and By the time the user notices that the light source has been used, the temperature fuse has already blown, so it is difficult for the user to restore the light source's functionality. To restore functionality, the temperature fuse or transformer must be replaced, which is a hassle. There was a problem in that the user ended up suffering from a great deal of trouble. In addition, in the latter case of the above conventional examples, it is true that when an overcurrent flows, an abnormality is notified by flashing the voltage monitor display element, but it is difficult to observe a specimen for a long time, especially with a microscope. Therefore, there is a risk that users may continue using the device without noticing the notification.

In view of the above-mentioned problems, the present invention has been developed to prevent overcurrent from flowing in the power supply circuit due to incorrect use of a light bulb or fluctuations in the primary power supply voltage.
It is an object of the present invention to provide an observation type light source device that maintains the functions of the light source device and can reliably notify a user of abnormalities.

[Means and effects for solving the problems] The observation light source device according to the present invention includes a light source, a power supply circuit that supplies power to the light source, a current detection circuit that detects the current flowing through the light source, and a current detection circuit that detects the current flowing through the light source. When the current value detected by the current detection circuit exceeds a preset upper limit value, an overcurrent signal is output to stop the power supply from the power supply circuit, and when the current value falls below a preset lower limit value. and a current value comparison/judgment circuit that stops the overcurrent signal and restarts power supply from the power supply circuit when the overcurrent signal occurs, and the abnormality is notified by blinking the light source. Furthermore, it is characterized by the addition of an abnormality notification sounding element which is activated by an overcurrent signal from the ifL value comparison and determination circuit.

These points will be explained in more detail.゛ Fig. 1 is a conceptual diagram of the present invention, in which power controlled by a power supply circuit 1 is supplied to a light bulb 2, and at this time, a current is transmitted to a current detection circuit 3 provided between the power supply circuit 1 and the light bulb 2. flows and an output voltage is generated.

Next, the output voltage of the current detection circuit 3 is determined by the current value comparison judgment circuit 4.
The voltage is compared with a preset reference voltage value (upper limit value), and if it is less than the reference voltage value (upper limit value), the cough circuit 4 does not output an overcurrent signal and the power supply circuit 1 operates normally. Note that the reference voltage value is a value that matches the output voltage value of the current detection circuit 3 when the maximum allowable current value (upper limit value) is output to the power supply circuit 1.

By the way, the installation of a light bulb 2 with a load higher than the rated load is also 1! Source circuit 1
When a current greater than the maximum allowable current flows through the power supply circuit 1 due to fluctuations in the primary power supply voltage supplied to the Immediately outputs an overcurrent signal to stop power supply to the light bulb 2. After that, when the current flowing through the light bulb 2 becomes smaller and the output voltage of the current detection circuit 3 becomes lower than the reference voltage value (lower limit value) set in advance by the current value comparison judgment circuit, the circuit 4 immediately stops the overcurrent signal. Power supply circuit 1
power supply will be resumed. In this way, by repeatedly stopping and restarting the power supply from the power supply circuit 1, the current value flowing through the power supply circuit 1 is suppressed within the permissible range, and the function of the light source device is maintained, and the light bulb 2 The abnormality is reliably notified to the user by blinking.

Furthermore, the current value comparison judgment circuit 4 outputs an over T! By adding a sound generating element 5 that operates based on the L flow signal, it is possible to reliably notify the user of an abnormality.

〔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 a 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-controlled dimming circuit, and as shown in FIG. 3, it includes a transformer 6 for generating a secondary voltage, a full-wave rectifier circuit 7, a time constant setting circuit 8, a triac trigger circuit 9, and a switching circuit. The stabilizing circuit 11 is connected to both the full-wave rectifier circuit 7 and the time constant setting circuit 8.
and connect the dimming volume 12 to the time constant setting circuit 8.
are connected. Moreover, the current detection circuit 3 is
? ! A current detecting element 13 that detects the current flowing from the power supply circuit to the light bulb 2, a load resistor 14 that generates an output voltage B from the output current of the current detecting element 13, a rectifying element 15 that rectifies the output, and a rectifying element 15 that rectifies the output. Output voltage C of element 15
The capacitor 17 charges the capacitor 17 via the charging resistor 16, and the discharging resistor 17 discharges the charge accumulated in the capacitor 17 (this value is significantly larger than the value of the charging resistor 16). Further, the current value comparison and determination circuit 4 compares the output voltage at the connection point between the capacitor 17 and the discharge resistor 19 and the DC power supply 19. Comparing with the reference voltage E determined by the resistor 20.21, when the output voltage is below the reference voltage E, the output voltage F is at the rLJ level, and when the output voltage is above the reference voltage E, the output voltage It consists of a comparison/judgment circuit 22 in which F is at the rHJ level, and its output voltage F is the power supply circuit 10.
The signal is now input to the trigger signal line of the time constant setting circuit 8 (FIG. 3).

Next, the operation of this embodiment will be explained.

The output waveforms of each part in a steady state are as shown in FIG. A current 1 flows from the power supply circuit 1 to the light bulb 2, and the output current of the current detection element 13 generates an output voltage B by the load resistor 14. Output voltage B is rectified by rectifier 15 and charged to capacitor 17 via charging resistor 16 .

At this time, since the value of the discharging resistor 18 is slightly larger than the value of the charging resistor 16, there is no influence of the discharging resistor 18 on charging.
0, and if the charging voltage D i of the capacitor 17 is smaller than the reference voltage E of the comparison/judgment circuit 22 in the saturated state, then
The output F of the comparison/judgment circuit 22 remains at the rLJ level, and the power supply circuit 1 continues to operate normally.

Next, we will explain the case where a light bulb 2 with a load higher than the rated load is attached due to incorrect use of the light bulb 2, or when an overcurrent flows into the power supply circuit 1 due to abnormal fluctuations in the primary power supply voltage supplied to the power supply circuit 1. . The output waveforms of each section at that time are as shown in FIG.

Similarly to the above, current A flows through current detection element 13 and output voltage B is generated by load resistor 14. The output voltage B is rectified by the rectifying element 15, and charging of the capacitor 17 via the charging resistor 16 is started.

Since overcurrent is flowing in power supply circuit 1, capacitor 17
The charging voltage reaches up to 6 of the reference voltage E (point shown in Figure 5), and the output voltage F of the comparison/judgment circuit 22 becomes rHJ.
level, and the time constant setting circuit 8 of the power supply circuit 1 is stopped, thereby stopping the trigger signal to the triac trigger circuit 9 and stopping the power supply to the light bulb 2. When the output voltage F of the comparison/judgment circuit 22 is inverted to the rHJ level, the reference voltage E is lowered to VL by the resistor 20.21. Then, when the power supply to light bulb 2 stops,
The output voltage B of the current detection element 13 also disappears, and the capacitor 1
The charging action on the capacitor 7 stops, and the capacitor 17 and the discharging resistor 18 start discharging. The reference voltage (■) at which the discharge voltage drops as the output of the comparison/judgment circuit 22 is reversed;
When the output voltage F of the comparison/judgment circuit 22 drops to
is reversed to "■," (point C in Figure 5), power supply circuit 1
power supply is restarted. As a result, Figure 5 a-b
The light bulb 2 is turned on during the period between b and c, turned off during the period b and c, and turned on again during the period c and d. By repeating this operation, the light bulb 2 is blinked and the user is notified of the abnormality. Furthermore, is
By intermittent power supply from the circuit 1 to the light bulb 2, the current value is kept within an allowable range, and damage to the circuit due to overcurrent is prevented. Therefore, even if the light bulb 2 is installed incorrectly, normal use within the rated current is possible again.

As described above, according to this embodiment, whether the light bulb 2 is misused or Tt, the primary of the i circuit 1? The light bulb 2 itself is made to blink as a notification method for an abnormality in which an overcurrent flows in the power supply circuit 1 due to fluctuations in the source voltage.As a result, the light source device cannot be used and the user is not informed. It is possible to reliably notify abnormalities. Therefore, there is no possibility that the user will continue using the device without noticing. Furthermore, since damage to the light source device itself can be prevented in an abnormal state, the function of the light source device can be immediately restored as long as the cause of the abnormal state is removed. Therefore, it does not take much time to recover the function, and the user suffers less inconvenience.

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

〔Effect of the invention〕

As described above, the light source device according to the present invention maintains the function of the light source device and reliably notifies the user of the abnormality when an overcurrent flows in the power supply circuit due to misuse of the light bulb or fluctuations in the primary power supply voltage. It has the important advantage of being able to

[Brief explanation of the drawing]

FIG. 1 is a conceptual diagram of the present invention, FIG. 2 is a circuit diagram of a first embodiment of a light source device for an observation system according to the present invention, FIG. 3 is a block diagram of a power supply circuit of the first embodiment, and FIGS. Figure 5 shows the first
FIG. 6 is a diagram showing output waveforms of each part in a steady state and an abnormal state in the embodiment, and is a circuit diagram of the second embodiment. DESCRIPTION OF SYMBOLS 1... i source circuit, 2... light bulb, 3... current detection circuit, 4... current value comparison judgment circuit, 5...
Sound generating element, 6...Transformer, 7...Full wave rectifier circuit, 8...Time constant setting circuit, 9...Triac trigger circuit, 10...Switching circuit, 11...
... Stabilization circuit, 12 ... Light control volume, 13
...Current detection element, 14...Load resistance, 15.
... Rectifying element, 16... Charging resistor, 17...
Capacitor, 18...Discharge resistor, 19...DC power supply, 20.21...Resistor, 22...Comparison/judgment circuit. Figure 1 Figure 2 Figures 1-3 Figure 4

Claims (2)

[Claims] (1) A light source, a power supply circuit that supplies power to the light source, a current detection circuit that detects the current flowing through the light source, and a current value detected by the current detection circuit that exceeds a preset upper limit value. A current that outputs an overcurrent signal to stop the power supply to the power supply circuit, and when the current value becomes equal to or less than a preset lower limit value, stops the overcurrent signal and restarts the power supply to the power supply circuit. A light source device for observation, comprising a value comparison and determination circuit, and for notifying an abnormality by blinking the light source. (2) The light source device according to claim (1), further comprising an abnormality notification sounding element operated by an overcurrent signal from a current value comparison and determination circuit.