Apparatus For Increasing The Lighting Of Photoflash Discharge Lamps

Abstract

Apparatus for increasing the lighting of photoflash discharge lamps including terminals for increased lamp lighting employs a diode, a trigger condenser, voltage dividing resistors and a synchroswitch in a main lighting circuit and the same components in a second circuit for the increased lamp lighting. Each diode in the main and increased lamp lighting circuits is connected in the positive direction relative to the discharge of its respective trigger condenser between a point connecting the trigger condenser to its voltage dividing resistors and a point connecting one side of the terminal to one side of its respective synchroswitch.

Description

The invention relates to apparatus for increasing the lighting of photoflash discharge lamps, and is more particularly directed to improvements in apparatus of the type having a terminal for the increased lighting provided in parallel with a synchroswitch.

In the heretofore known systems for increasing the lighting of photoflash discharge lamps, a terminal for a synchroswitch has been provided to connect a main lamp in parallel with a synchroswitch circuit for lamps to furnish increased lighting. By closing the synchroswitch for the main lamp, light from the synchroswitch circuit is furnished at the same time for the lamp providing the increased lighting. Since the synchroswitch circuit is connected in parallel, the voltage dividing ratio is changed to a considerable extent when a voltage dividing circuit is used in conjunction with the synchroswitch circuit. When it is desired to include a monitor circuit, together with a voltage dividing circuit, the working point of the monitor also is changed to a considerable extent, and as a result, overvoltage is impressed upon the main condenser. Also, where the system includes means for indicating voltage, such as a neon tube, the voltage for lighting such tube changes to a substantial extent, and accordingly, the voltage for indicating is not suitable.

The purpose of the present invention is to overcome the limitations referred to above. Apparatus is provided to prevent the resistance value of a voltage dividing resistor from being changed, in which a trigger is discharged in the positive direction by utilizing the characteristics of a semiconductor diode, and to connect in parallel synchrocircuits so that high resistance in the reverse direction is obtained.

According to the present invention, by connecting each diode between a point connecting the trigger condenser and the voltage dividing resistors and a terminal for lamps, of a main lighting circuit and a second circuit for increased lamp lighting, respectively, it is possible to light the lamp of the second circuit without affecting the operating voltages of the monitor and the voltage indicator.

In accordance with the invention, apparatus for increasing the lighting of photoflash discharge lamps having a terminal for increased lamp lighting is arranged in parallel with a synchroswitch, and a circuit is provided in which a diode is connected in the positive direction relative to the discharge of a trigger condenser between a point connecting the trigger condenser and voltage dividing resistors, and a point connecting one end of the terminal for the increased lamp lighting and one end of the synchroswitch.

This invention will be described with reference to an illustrated embodiment shown in the attached drawing, in which:

FIG. 1 shows apparatus for increasing the lighting of photoflash discharge lamps comprising a main lighting circuit and a cooperable second circuit for increased lamp lighting.

As illustrated, the main lighting circuit comprises a DC-DC converter 1 connected to a power source 2, such as a battery, to furnish energy to the converter, a switch 3 being positioned intermediate the converter and the power source. A monitor circuit 4 is provided to control the oscillation of the converter. A main condenser 5 is connected to conductors extending from each side of the converter. As shown, a glow tube 6 is provided for indicating voltage, and voltage dividing resistors 7, 8 and 9 respectively provided to control the operating voltages of the glow tube 6, the monitor signal circuit 4, and trigger circuit. A trigger condenser 10, a diode 11, and a synchroswitch 12 are connected to the voltage dividing resistors as shown. The diode 11 is positioned in the circuit between the points b and c, with the diode connected in a positive direction relative to the discharge of the trigger condenser 10. Terminals 13 and 13a are respectively connected to the ends or sides of the synchroswitch 12. A trigger transformer 14 is connected to the opposite side of the synchroswitch 12. A photoflash discharge lamp is indicated at 15. These elements are connected to one another as shown, and as previously indicated, constitute the main lighting circuit.

For increased lamp lighting, a second circuit is provided comprising the elements or components designated 5' through 15'. These components correspond to or are the same as the components of the main lighting circuit having the reference characters 5 through 15, respectively. The diode 11' is positioned in the circuit between the points b' and c', with the diode connected in a positive direction relative to the discharge of the trigger condenser 10'. For a power source to charge the main condenser 5' of the increased lamp lighting circuit, it will be apparent that a DC-DC converter, an integrating high voltage dry element battery, or the like, may be used. Also, the power source for this second circuit may be the same one as used to furnish power for the main lighting circuit.

By connecting the terminals 13', 13a' of the increased lamp lighting circuit to the terminals 13, 13a of the main lighting circuit by means of cords 16, 16a, the light provided by the photoflash discharge lamp 15', together with the light furnished by the lamp 15, is provided upon closing the synchroswitches 12, 12'.

When the power source switch 3 is closed to cause the converter 1 to operate, the main condenser 5 of the main lighting circuit is charged. When charged to a given voltage, monitor circuit 4 operates and the converter interrupts its operation. Under this condition, and when the synchroswitch 12 is closed, the energy charged in the trigger condenser 10 is discharged through the diode 11 and the primary side of the trigger transformer 14 causing the trigger circuit to operated and the photoflash discharge lamp 15 to be lighted. When the terminals 13, 13a of the main lighting circuit are connected to the terminals 13', 13a' of the increased lamp lighting circuit, as by the cords 16, 16a, increased light is simultaneously furnished by the photoflash discharge lamp 15' upon the closing of the synchroswitch 12'.

The significance of the presence of the diodes 11, 11' in the main lighting and increased lamp lighting circuits will be apparent from the following. When the terminals 13, 13a and the terminals 13', 13a' are connected by the cords 16 and 16a, the voltage dividing circuit of the main lighting circuit or side and the voltage dividing circuit on the increased lamp lighting circuit or side are connected in parallel. Accordingly, the resistances in series of the voltage dividing resistors 8 and 9 and of the voltage dividing resistors 8' and 9' result in resistance values which are respectively halved. Therefore, the charging voltage in the trigger condensers 10 and 10' drop to a substantial extent, and it becomes impossible to obtain enough trigger pulses to discharge the photoflash discharge lamps 15 and 15'. Also, the signal voltage from the voltage dividing resistor 8 drops to a considerable extent so that the working point of the monitor circuit 4 ascends to impress overvoltage on the main condenser 5. As a result, the main condenser would incur damage.

On the other hand, when a diode is connected to the trigger condenser and the synchroswitch in each of the main lighting and increased lamp lighting circuits, as above described, and when the synchroswitches of the two circuits are connected in parallel, the discharge current of the trigger condenser in each circuit is discharged through the primary side of the respective circuits without difficulty, utilization being made of the positive directional characteristic of each of the diodes. Due to the relationship of the voltage dividing resistors 8 and 9 in the main lighting circuit and the voltage dividing resistors 8' and 9' in the increased lamp lighting circuit, the diode 11' will turn to the reverse direction and diode 11 will turn to the reverse direction so that there is no flow of current, and no variation will occur in the operating voltage.

Claims

What I claim:

1. Apparatus for increasing the lighting of photoflash discharge lamps comprising a first circuit for main lighting and a second circuit for increased lamp lighting, the first and second circuits each comprising a trigger condenser, voltage dividing resistors, a synchroswitch and diode, and each circuit having terminals connected to its respective synchroswitch for the connection of the first and second circuits in parallel, each diode in the first and second circuits being connected in the positive direction relative to the discharge of its respective trigger condenser between a point connecting the trigger condenser to the voltage dividing resistors and a point connecting one side of each circuit's terminals to one side of its respective synchroswitch.

2. Apparatus according to claim 1 including a monitor circuit in said first circuit, and further including a main condenser and a glow tube in each of said first and second circuits; wherein one of the voltage dividing resistors in said first circuit controls the operating voltage in the monitor circuit; and wherein the voltages of the glow tube and of the trigger condenser in each of the first and second circuits are each respectively controlled by a voltage dividing resistor in each of said circuits.

3. Apparatus according to claim 2 including a trigger transformer in each of said first and second circuits; and wherein each trigger transformer is connected to the opposite side of its respective synchroswitch.