JPS59221997A - Device for firing discharge lamp - 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 The present invention relates to a lighting device for a small discharge lamp light source that is suitable for use in photographing and filming images such as photographs and videos.

Light sources used for imaging purposes such as photographs and videos include light bulbs such as incandescent lamps and halogen lamps.

Although these bulbs have the advantage of being relatively inexpensive,
The luminous efficiency is as low as 10 to 15-6m, about 4, and it consumes a lot of power, so it has the disadvantage that the lighting time is short, especially when used as a battery power source.

Therefore, it is conceivable to use a high-pressure metal vapor discharge lamp such as a mercury lamp or a metal halide lamp, which has high luminous efficiency, as a light source.

However, using such a light source requires an inductor ballast for lighting, and has the disadvantage that the device becomes large. In addition, there is a drawback that it takes time for the discharge lamp to start up and restart.

High-pressure metal capped discharge lamps such as mercury lamps and metal halide lamps require 2 to 3 minutes to stabilize after being turned on, and once they are turned off, they do not turn on again until the temperature of the arc tube has fallen sufficiently. It takes about a minute to restart. Such starting,
To solve the problem of restarting, conventional methods have applied high voltage pulses to discharge lamps to cause them to start and restart instantly.

However, since this requires the use of high voltage pulses of several tens of kilovolts, there are problems with the insulation of the lighting circuit and the insulation distance between the lead wires of the lamp base, making it difficult to put it into practical use. In other words, it was necessary to use a specially designed lighting device and a lamp with a special base, which increased the price and caused the inconvenience of increasing the size of the device, which hindered the spread of general use. .

For these reasons, high-pressure metal vapor discharge lamps have rarely been used in the fields of photography and videography.

The present invention aims to provide a novel and practical compact discharge lamp lighting device that solves the above-mentioned problems.

Hereinafter, the discharge lamp lighting device according to the present invention will be explained with reference to the drawings. In FIG. 1, 1 is a DC power source obtained by rectifying a battery or a commercial AC power source, and 2 is a power switch. 3 is a high frequency inverter using semiconductors such as transistors, and has a frequency of several 10 KH2 to 100 K1-I
Generates high frequency power of about 2. On the output side of this high frequency inverter 3, a plurality of impedance elements 4a,
A (full wave) rectifier 6 is connected via a current limiting device g4 consisting of 4t) and an impedance value conversion means of the current limiting device 4.

(A discharge lamp 7 is connected to the output side of the full-wave rectifier 6.

Next, the operation of the discharge lamp lighting device according to the present invention will be explained.

First, when waiting to irradiate the discharge lamp 7,
Turn on the mold temperature switch 2.

Then, high-frequency power is output to the output side of the high-frequency inverter 3, which is energized by the DC power source 1, and this output is rectified by the full-wave I rectifier 6 and supplied to the discharge lamp 7. 7 lights up when starting □.In this case,
The impedance value of the current limiting device 6 may be made small by the conversion means 5 or made large, but if it is made small, it will take 7 minutes for the discharge lamp, but only at the beginning. It is unavoidable that it will take this much time.

However, one of the features of the present invention is that the restart time of the discharge lamp 7 can be shortened by operating the converting means 5. When a switch is used as the conversion means 5, the beginning of the discharge lamp! 11
The converting means 5 is closed when the lamp is turned on and during normal lighting, but if the converting means is opened when the use is interrupted, the power is transferred to the impedance element 4a.

4b, the discharge lamp 7 is lit in a dimmed state and maintains discharge with low power. When starting to use θ again, the converting means 5 is closed, and the luminous flux of the discharge lamp is restored with a slight delay.

Although this delay depends on the amount of power input to maintain the discharge and the interruption time of use, that is, the waiting time for restart, it can be made to such an extent that it is not a problem in practice.

The solid line in FIG. 2 is a graph obtained by examining the rise of the luminous flux when a 50 W shimetal halide lamp was lit using the lighting device according to the present invention and then restarted with various restart waiting times. This figure shows that when the restart wait time is short, about several tens of seconds, the rate of rise of the luminous flux varies depending on the length of the restart wait time, but when it exceeds 1 minute, there is a constant delay no matter how long it is. and stands up. this is,
If the restart wait time is longer than 1 minute, the arc tube will be cooled 1.
This is thought to be because the e-tube heat generation is almost in equilibrium with the heat generated by the operation of the e-tube, and the heat generated by the e-tube is due only to the power input during restart standby.

In this way, in the present invention, a small amount of power is input during restart standby to keep the arc tube temperature high, so even if the restart standby time is long, the delay in the rise of the luminous flux during re-excitation can be shortened. It has the advantage of being able to The dotted line in the figure shows that the conventional upstream circuit using high voltage pulses, which does not implement the present invention, has a significant IC delay.

Note that in order to minimize the input power for maintaining discharge during restart standby, it is generally more advantageous to use a DC lighting method that does not generate a restriking voltage. Therefore, in the present invention, the output of the high frequency inverter 3 is applied to the discharge lamp 7 via the (residual) rectifier 6 and filter capacitor 8. In this case, part of the current limiting impedance is shared by the inductance of a single cage transformer (not shown) inside the high frequency inverter, and the other part is shared by the capacitance of the capacitor 4a.

During restart standby, the capacitances 4a and 4b are connected in series by opening the conversion means 5, so the current decreases due to the combined impedance of 4a and 4b, resulting in a standby state. 115 during normal lighting of discharge lamp manual gravity during restart standby
It can be reduced to 8 degrees. For example, the tube power is 50W for a discharge lamp.
When using the rated metal ride brake, the restart delay time can be sufficiently shortened with low I restart standby input power. Although Fig. 1 shows an example in which a plurality of impedance elements 4a and 4b are connected in series, the total impedance can be reduced by connecting them in parallel via a switch and turning on the switch during restart standby. It may be configured to increase the amount. Impedance elements 4a, 4b, which constitute the current limiting device...-
... may be a choke coil, and in the case of a choke coil, it is more economical to provide a tap and cut it because only one core is required. However, in general, using a capacitor is smaller and lighter. Further, the impedance value converting means 5 of the current limiting device 4 may be an electrical or mechanical switch.

According to the discharge lamp lighting device of the present invention, since the high-frequency inverter 3 is used, the current limiting device 4, which acts as a stabilizer, is small, and a small choke coil using a ferrite core and a small capacitor are used. Use 'fc@'. Since the cylindrical frequency inverter itself is miniaturized using semiconductor switching elements such as transistors, the device as a whole can be made extremely small and lightweight, and can also be made portable.

Moreover, as mentioned above, the rise time of the luminous flux at the time of restart can be shortened, so that it is suitable as a lighting device in the field of video shooting such as photography.

High-pressure metal vapor several watt lamps can be used as the light source, so
Compared to those using white light bulbs, it also has the advantage of providing a highly efficient and compact light emitting device.

[Brief explanation of the drawing]

FIG. 1 is a circuit diagram showing an embodiment of the discharge lamp lighting device according to the present invention, and FIG. 2 is a diagram showing the relationship between the restart standby time, 'Jt, and the start-up of the bundle, showing the effects of the present invention. In Fig. 1, (-) indicates 1.--DC power supply, 3. High-frequency inverter, 4. Current-limiting device, 4a, 4b.. Impedance element, 5. 6... (Full wave I rectifier, 7... Discharge lamp, 8... Filter capacitor.

Claims (2)

[Claims] (1) A plurality of impedance elements (4
A current limiting device (4) consisting of a), (4b)... and a means (5) for converting the impedance value of the current limiting device (4)
A full-wave rectifier (6) is connected through the (full-wave) rectifier (6), and a discharge lamp (7) is connected to the output side of the (full-wave) rectifier (6). During standby, the impedance value of the current limiting device (4) is increased to dim the discharge lamp (7), and when the discharge lamp (7) is irradiating, the converting means (5) is used to limit the current. A discharge lamp lighting device characterized in that the impedance value of the device (4) is reduced to perform brighter lighting. (2) Part or all of the current limiting device ff6' (41 impedance elements (4a), (4b), etc. are constituted by capacitors, claim 1). Discharge and lamp lighting device described.