US3823344A

US3823344A - Arrangement provided with at least two combustion flash bulbs

Info

Publication number: US3823344A
Application number: US00366445A
Authority: US
Inventors: P Havas
Original assignee: US Philips Corp
Current assignee: US Philips Corp
Priority date: 1972-06-17
Filing date: 1973-06-04
Publication date: 1974-07-09
Anticipated expiration: 1991-07-09
Also published as: FR2189978A1; NL7208320A; CH563700A5; BE801019A; CA998091A; IT988254B; SE388946B; GB1433028A; JPS4964422A; ES415962A1; FR2189978B1

Abstract

The invention relates to an arrangement for the successive ignition of at least two combustion flash bulbs in which each bulb is arranged in series with a thyristor. The invention provides a solution for rendering the thyristors conducting with the aid of a shift register which is provided with cores of a magnetic material having a substantially rectangular hysteresis loop.

Description

United States Patent [191 Havas July 9, 1974 ARRANGEMENT PROVIDED WITH AT LEAST TWO COMBUSTION FLASH BULBS [75] Inventor: Pal Geza Havas, Emmasingel,

Eindhoven, Netherlands [73] Assignee: U.S. Philips Corporation, New

York, N .Y.

[22] Filed: June 4, 1973 [2]] Appl. No.: 366,445

[30] Foreign Application Priority Data 11/1971 Ellin 431/95 3,676,045 7/1972 Watrous et a1. 431/95 Primary Examiner-Carroll B. Dority, Jr. Attorney, Agent, or Firm-Frank R. Trifari; Bernard Franzblau ABSTRACT The invention relates to an arrangement for the successive ignition of at least two combustion flash bulbs in which each bulb is arranged in series with a thyristor. The invention provides a solution for rendering the thyristors conducting with the aid of a shift register which is provided with cores of a magnetic material having a substantially rectangular hysteresis loop.

8 Claims, 2 Drawing Figures PAI I JUL 91914 3823344 sum 2 or 2 The invention relates to an arrangementprovided with at least two combustion flash bulbs and with controlled semiconductor rectifiers for successively igniting said bulbs, each bulb being arranged in series with such a controlled semiconductor rectifier, while each of these series arrangements forms part of a branch connecting two terminals of a first direct voltage source, each of the controlled semiconductor rectifiers being provided with a control circuit.

A known arrangement of the type mentioned is described, for example, in United Kingdom Pat. specification No. 1,262,623. A drawback of this known arrangement is thatfor flashing a subsequent bulb in the row a number of transistors is required to render the controlled semiconductor rectifier arranged in series with said subsequent bulb conducting. Furthermore, the closer a bulb is located near the end of the row of bulbs, the greater the number of required transistors. In addition, if only one of these transistors does not operate properly, an interconnection to a subsequent bulb is not established Anobject of the invention is to provide a simple arrangement in which the number of elements for interconnection to a subsequent bulb is small.

According to the invention an arrangement provided with at least two combustion flash bulbs and with controlled semiconductor rectifiers for successively igniting said bulbs, each bulb being arranged in series with such a controlled semiconductor rectifier and in which each of these series arrangements forms part of a branch connecting two terminals of a first direct voltage source, each of the controlled semiconductor rectifiers being provided with a control circuit is characterized in that a core of a magnetic material having a substantially rectangular hysteresis loop and two stable remanence states is added to each bulb, and that the control circuit of the controlled semiconductor rectifier arranged in series with a bulb is connected to a first winding of the core added to said bulb, a second winding of said core forming part of one of the branches connecting the two terminals of the first direct voltage source together and accommodating one of the other bulbs, a third winding of the core added to a bulb arranged in series with corresponding windings of the cores added to the other bulbs being connected to an auxiliary arrangement for generating a shift pulse.

An advantage of an arrangement according to the invention is that the interconnection to a subsequent flash bulb can be realized with a small number of elements namely magnetic cores. It is ensured beforehand that only one of these cores is located in a preferred position. Subsequently the said core is brought to its other stable remanence state by means of a shift pulse. As a result a voltage is applied to the control circuit of a controlled semiconductor rectifier via the so-called second winding of this core. This semiconductor rectifier is rendered conducting thereby so that the flash bulb arranged in series therewith flashes. The said shift pulse does not have any influence on the other cores of the arrangement because these cores were not located in their preferred position. By flashing the said bulb a current will flow which causes the core added tothe subsequent bulb to be changed over to its other remanence state. The result of all this is that only one core is located in its preferred position again, namely the core which is added to the subsequent bulb in the rowv of bulbs. .When a subsequent shift pulse is applied to the third winding of the cores, the subsequent bulb will flash in a manner similar to that as described hereinbefore, etc.

It is to be noted that it is known from Swiss Pat. Specification No. 382,224 to use cores having three windings in a circuit in which one of these windings receives a shift pulse and in which always a subsequent core is brought to the preferred position. In this known circuit the duration of the current through a user is, however, dependent on the duration of conductance of a transistor arranged in series with said user. For use in combustion flash bulbs this is a drawback because either the flash bulb does not sufficiently flash or extra auxiliary circuits are required to maintain the transistor conducting for a longer period.

It is not necessary that a flash bulb in an arrangement according to the invention is only in series with one of the controlled semiconductor rectifiers. It is alternatively possible for this bulb to be arranged in series with, for example, two of the controlled semiconductor rectifiers.

The shift pulse may be generated, for example, in an auxiliary circuit which is provided with a controlled semiconductor rectifier rendered conducting for a short period and which is arranged in series with the socalled third windings of the cores.

In a preferred embodiment according to the invention in which the shift pulse auxiliary arrangement is also provided with a core of a magnetic material having a substantially rectangular hysteresis loop and two stable remanence states, the latter core has a first winding which is connected through a switching element to a first auxiliary voltage source, and the series arrangement of the third windings of the cores added to the bulbs is connected to a second winding of the core of the shift pulse auxiliary arrangement, the branches comprising the bulbs and connecting the two terminals of the first direct voltage source together also accommodating a further winding of the core of the shift pulse auxiliary arrangement.

An advantage of this preferred embodiment is that the shift pulse auxiliary arrangement may be very simple. The core in this shift pulse auxiliary arrangement is brought to the other remanence state due to the switching element being rendered conducting so that the shift pulse is generated. This pulse is then applied through the third windings of the cores added to the bulbsFinally the core of the shift pulse auxiliary arrangement is reset to the original remanence state by the return currentof the bulbs. Then this core in the shift pulse auxiliary arrangement is thus ready again for generating a subsequent shift pulse.

It is feasible that the return currents of the bulbs flow through different further windings of the core of the shift pulse auxiliary arrangement.

In a further preferred embodiment of an arrangement according to the invention in which the branches comparing the bulbs and connecting the two terminals of the first direct voltage source together have a common conductor part, the further winding of the core of the shift pulse auxiliary arrangement is present in this common conductor part.

An advantage of this preferred embodiment is that the number of windings on the common core, that is to say, the core of the shift pulse auxiliary arrangement may be very small.

It is feasible, that the sequence viewed from the positive terminal to the negative terminal of the first direct voltage source is completely arbitrary for, the bulbs the controlled semiconductor rectifier and the second winding of a core.

In a preferred embodiment according to the invention in which in each branch comprising a bulb and connecting the two terminals of the first direct voltage source together the bulb is located closer to the positive terminal of the first direct voltage source than the controlled semiconductor rectifier forming part of said branch and the second winding of a core added to one of the other bulbs, the end of each bulb remote from the positive terminal is connected to its own second auxiliary voltage source of limited capacity.

An advantage of this preferred embodiment is that if a bulb is defective or if it were removed from its holder, a current still flows through the relevant second winding of the core when the controlled semiconductor rectifier becomes conducting, which current brings this core to its other remanence state. This current is then withdrawn from this second auxiliary voltage source of limited capacity. When the second auxiliary voltage source is discharged, the controlled semiconductor rectifier, if chosen to be a thyristor, will become nonconducting again.

In a further improvement of the latter preferred embodiment the second auxiliary voltage sources of limited capacity each consist of a capacitor which is connected in series with a resistor to a second direct voltage source. This capacitor is thus always charged through this resistor. The RC-time is chosen to be such that during discharge of the capacitor substantially no current flows through the resistor.

It is feasible that in the factory where an arrangement according to the invention is made one of the cores is already set to its preferred position and the other cores are set to the non-preferred position.

In a further preferred embodiment according to the invention in which the switching element in series with the first winding of the shift pulse auxiliary arrangement is a thyristor, the control electrode of this thyristor is connected through a flash contact of a photocamera to the positive terminal of a second direct voltage source.

An advantage of this embodiment is that the user of the arrangement can bring the cores to the nonpreferred position himself without flashing. In fact, it is feasible that sometimes more than one of the cores has come to its preferred position while this is not desirable. The used switch shunting the flash contact may then serve for a renewed setting, also sometimes referred to as reset.

When such a reset has taken place it is also to be ensured that it is possible to subsequently place one of the cores in its preferred position again. This may be effected by providing, for example, one or more of the cores with extra windings and by subsequently connecting them to a voltage source.

In a further embodiments of the latter preferred arrangement according to the invention in which a first switch connected in parallel with the flash contact is present between the control electrode of the thyristor and the positive terminal of the second direct voltage source, this first switch is mechanically coupled to an auxiliary switch in a part which is common for (n l) of the branches, where n is the number of bulbs, an in the open state of the first switch the auxiliary switch is closed, and in the closed state of the first switch the auxiliary switch is open.

An advantage of this preferred embodiment is that during the reset a current which is not too large flows through a winding of the core of the shift pulse auxiliary arrangement. A too large current is then prevented by the so-called auxiliary switch.

In a further preferred embodiment according to the invention a third auxiliary voltage source is connected through a second switch to the second winding of a core added to one of the bulbs, which second winding is present in that branch which connects the terminals of the first direct voltage source and which is free from the auxiliary switch.

An advantage of this embodiment is that by closing this switch the relevant core can be brought to its preferred position in a simple manner after resetting. The preferred position is then understood to mean a remanence state of the core which is reversed when a shift pulse is applied to the core.

The invention will be described in greater detail with reference to a drawing. In this drawing:

FIG. 1 shows an electrical circuit diagram of a first arrangement according to the invention;

FIG. 2 shows a second electrical circuit arrangement according to the invention.

In FIG. 1, 1 denotes a low-voltage combustion flash bulb. 2, 3 and 4 are similar combustion flash bulbs. A core provided with three windings is added to each bulb. For bulb 1 this is core K1, for bulb 2 it is K2, for bulb 3 it is K3 and for bulb 4 it is K4. 5 is an input terminal of the arrangement which is intended to be connected to the positive terminal of a direct voltage source. The terminals 6 and 6a to 6d are all connected to the negative terminals of said direct voltage source. The terminal 5 is connected to a resistor 7. The other end of this resistor 7 is connected to a capacitor 8. The other end of this capacitor 8 leads to the negative terminal 6b of the direct voltage source. The lamps l to 4 are arranged in parallel and are connected to the junction of the resistor 7 and the capacitor 8. The other end of the bulb l is connected to a controlled semiconductor rectifier Tl, a thyristor. The cathode of this thyristor T1 is connected to a winding W22 of the annular core K2 of a magnetic material having a rectangular hysteresis loop and two remanence states. The other end of winding W22 is connected to a common return lead 9. This return lead is connected through an auxiliary switch 18a and a winding N2 of a further core G to the negative terminal 6d of the direct voltage source. The core G constitutes the most important part of a shift pulse auxiliary arrangement.

Furthermore the thyristor T1 is provided with a control circuit. This control circuit is connected to a first winding Wll of the core Kl. One end of the winding Wll is connected through a diode 11 to a capacitor 12. The junction between the diode 11 and the capacitor 12 is connected to the control electrode of the thyristor T1. The other end of the capacitor 12 is connected to the cathode of the thyristor T1.

The bulb 2 is arranged in series with a thyristor T2. The bulb 3 is arranged in series with a thyristor T3, and the bulb 4 is arranged in series with a thyristor T4. The thyristors T2, T3 and T4 are provided with a control circuit similarly as the thyristor T1. The control circuit of the thyristor T2 is connected to a winding W21 of the core K2. The core K2 is furthermore provided with a third winding W23. Windings similar to those of W23 are also provided in the form of winding W13 on the core K1, as winding W33 on the core K3 and as winding W43 on the core K4. The'windings W43, W33, W23 and W13 are arranged in series and are connected through a diode to a winding N3 of the coreG in the shift pulse auxiliary arrangement. The other windings of the core K3 are denoted by W32 and W31. The other windings of the core K4 are denoted by W42 and W41. The other winding of core K1 is denoted by W12. The core G has a winding N1 one end of which is connected to a junction between a resistor 14 and a capacitor 15 which constitute a connection between the positive terminal 5 and the negative terminal 6 of the direct voltage source. The other end of the winding N1 is connected through a thyristor 16 to the terminal 60. The control electrode of the thyristor 16 is connected to a contact 17 of the camera flash contact as well as to a switch 18. This switch 18 is mechanically coupled to the auxiliary switch 18a. The other end of the switch 18 is connected both through a resistor 20 to the positive terminal 5 and to the other end 19 of the camera flash contact. 21 denotes a resistor which in series with a capacitor 22 is connected between the positive terminal 5 and the negative terminal 6a of the direct voltage source. The junction between the resistor 21 and the capacitor 22 is connected through a switch 23 to a point between the thyristor T4 and the'winding W12 of the core K1. I

Finally'a series arrangement of a resistorand a capacitor is added to each bulb. These are the resistor R1 and the capacitor C1 for bulb 1. The junction between this resistor R1 and the capacitor C1 is connected to a junction between the bulb l and the thyristor T1. Similarly, a series arrangement of a resistor R2 and a capacitor C2 is added to bulb 2. Further there are resistor R3 and capacitor C3 for bulb 3 and resistor R4 and capacitor C4 for the last bulb (4).

The circuit described operates as follows. Firstly the switch 18 is brought to its closed state and consequently the auxiliary switch 18a is brought to its open state. As a result thyristor 16 will be rendered conducting. This means that the previously charged capacitor 15 is discharged across the winding N1 of the core G and across the said thyristor 16. Consequently, the remanence state of the core G is changed. This results in a voltage induction in the winding N3 of the core G, which is passed over the shift line via the diode 10 across the winding W13, W23, W33 and W43 of the cores. All these cores will then be brought to the socalled non-preferred position (reset). A possible return current through winding N2 and originating from the resistor 20 so that this thyristor becomes conducting. As a result the capacitor 15 will again be discharged through the winding N1 and the remanence state of 1 core G will be reversed so that a pulse is again given through the shift line. This shift line will not bring about anything for the cores K2, K3 and K4, but the remanence state of core K1 will now be reversed to the nonpreferred position. As a result a pulse will be generated in the winding W11, which pulse renders the thyristor T1 conducting. Consequently the bulb 1 flashes. The current flowing in the circuit 8, 1, T1, W22, N2, 6d will firstly bring the core K2 to its preferred position and furthermore reset the core G to its original remanence state again. When subsequently the camera flash contact is operated for a second time the magnetic state of the core K2 will be reversed by the shift pulse so that the thyristor T2 is rendered conducting. The other cores are not influenced in this case because all of them, also the core K1, are in their non-preferred position, etc. If the thyristor T4 is rendered conducting a current flows through the winding W12 of the core K1 so that this first core is set to its preferred position again. If for some reason or other a bulb might be defective or removed from its holder, the relevant capacicapacitor C4, across winding W12, will bring the core G to its original remanence state.

Subsequently switch 18 is opened and switch 180 is closed. The switch 23 is then closed so that the capacitor 22 is discharged across the winding W12 and the winding N2. As a result the core K1 is brought to the preferred position and the remanence state of core G is reversed. The arrangement is then ready for flashing.

tor added thereto, for example, C1, C2, C3 or C4 will be discharged through the relevant thyristor, that is to say, T1, T2, T3 or T4 and then still set the next core to its preferred position. v

The arrangement for resetting and writing in with the resistor 21, capacitor 22 and switch 23 may be omitted if the preferred position of only one of the cores is set in the factory where the arrangement is made and if the cores are sufficiently shielded from magnetic fields. In that case the thyristor 16 may also be omitted and the camera flash contact may be provided between the winding N1 and the negative terminal 6d of the direct voltage source.

In the circuit described the number of control elements is only small by the choice of the annular cores, and generating of the shift pulse is very simple. The return current for the bulbs is used to reset the common core to its original remanence state.

The arrangement of FIG. 1 may be provided, for example, at least partly on a printed wiring board (integrated circuit).

The arrangement of FIG. 1 may be accommodated, for example, for a larger or smaller part in a photocamera. It is also feasible that this arrangement is formed as an adapter which constitutes the connection be tween a camera and an expandable flash bulb unit. This unit accommodates the bulbs 1 to 4. The invention relates of course also to arrangements in which the number of bulbs is larger or smaller than four.

In a practical embodiment the cores K1 K4 were ferrite cores. The resistor 7 had a value of approximately 2.2 k. ohm and the capacitor 8 had a value of approximately 200 #F. The resistors R1 R4 each had a value of approximately 47 k.ohm and the capacitors Cl C4 had a value of approximately 2.2 F. The capacitor 12 had a capacitance of approximately 47 kpF. The

resistors

14 and 21 each had a value of approximately 47 k.ohms and the

capacitors

15 and 22 had a capacitance of approximately 1 MP and 6.8 11F, respectively.

FIG. 2 shows a slightly different circuit using five bulbs denoted by 101 to 105. These again are low voltage combustion flash bulbs. 106 denotes the positive terminal of a direct voltage battery "and 107 denotes the negative terminal of this battery. Bulb 101 is in series with a thyristor T101 and with awinding D12 of a core Bl. Bulb 102 is in series with a winding D22 of a core B2 and a thyristor T102. Bulb 103 is in series with the thyristor T101 and with the winding D32 of a core B3. In addition this bulb 103 is in series with the thyristor T102. The bulb 104 is in series with the thyristor T102. The bulb l04 is in series with a thyristor T104 and with a winding D42 of a core B4. The bulb 105 is also in series with the thyristor T104 and in addition with a winding D52 of a core B5. The windings D13, D23, D33, D43 and D53 of the five cores are connected in series and are connected to a shift pulse auxiliary arrangement 108. As in the case of FIG. 1 the return current of the bulbs flows through a core'(15) of the shift pulse auxiliary arrangement. The sequence in which the bulbs are flashed is 101, 102, 103, 104, 105. To this end the thyristor T101 is rendered conducting and subsequently the thyristor T102 is rendered conducting. Subsequently both the thyristor T101 and the thyristor T102 are rendered conducting so that the bulb 103 flashes. Finally the thyristor T104 is rendered conducting. Subsequently both the thyristor T104 and the thyristor T102 are rendered conducting for flashing the last bulb 105.

All this is realized by causing the core B1 to reverse when the bulb 101 is flashed, and by causing the core B2 to reverse when the bulb 102 is flashed while for the next shift pulse the core B2 applies a trigger pulse both to thyristor T101 and to thyristor T102 so that the third bulb, namely bulb 103 is subsequently flashed. Similarly, when applying a shift pulse to the core B4 set to its preferred position a control signal is passed both to thyristor Tl04 and to thyristor T102 causing the bulb 105 to be flashed. I

An advantage of the arrangement of FIG. 2 is that only three thyristors are required for flashing five bulbs.

What is claimed is:

1. An arrangement provided with at least two combustion flash bulbs and with controlled semiconductor rectificrs for successively igniting said bulbs, each bulb being arranged in series with such a controlled semiconductor rectifier and in which each of said series arrangements forms part of a branch connecting two terminals of a first direct voltage source, each of the controlled semiconductor rectifiers being provided with a control circuit, characterized in that a core of a magnetic material having a substantially rectangular hysteresis loop and two stable remanence states is added to each bulb, and that the control circuit of the controlled semiconductor rectifier arranged in series with a bulb is connected to a first winding of the core added to said bulb, a second winding of said core forming part of one of the branches connecting the two terminals of the first direct voltage source together and accommodating one of the other bulbs, a third winding of the core added to a bulb arranged in series with corresponding windings of the cores added to the other bulbs being connected to an auxiliary arrangement for generating a shift pulse.

2. An arrangement as claimed in claim 1, in which the shift pulse auxiliary arrangement is also provided with a core of a magnetic material having a substantially rectangular hysteresis loop and two stable remanence states, characterized'in that the latter core has a first winding which is connected through a switching element to a first auxiliary voltage source, the series arrangement of the third windings of the cores added to the bulbs being connected to a second winding of the core of the shift pulse auxiliary arrangement, the branches comprising the bulbs and connecting the two terminals of the first direct voltage source together also accommodating a further winding of the core of the shift pulse auxiliary arrangement.

3. An arrangement as claimed in claim 2 in which the branches comprising the bulbs and connecting the two terminals of the first direct voltage source together have a common conductor part, characterized in that the further winding of the core of the shift pulse auxiliary arrangement is present in said common conductor part.

4. An arrangement as claimed in claim 1, in which in each branch comprising a bulb and connecting the two terminals of the first direct voltage source together the bulb is located closer to the positive terminal of the first direct voltage source than the controlled semiconductor rectifier forming part of said branch and the second winding of a core added to one of the other bulbs, characterized in that the end of each bulb remote from the positive terminal is connected to its own second auxiliary voltage source having a limited capacity.

5. An arrangement as claimed in claim 4, characterized in that the second auxiliary voltage sources of limited capacity each consist of a capacitor which is connected in series with a resistor to a second direct voltage source.

6. An arrangement as claimed in claim 2 in which the switching element in series with the first winding of the shift pulse auxiliary arrangement is a thyristor, characterized in that the control electrode of said thyristor is connected through a flash contact of a photocamcra to the positive terminal of a second direct voltage source.

7. An arrangement as claimed in claim 6, characterized in that a first switch connected in parallel with the flash contact is present between the control electrode of the thyristor and the positive terminal of the second direct voltage source, said first switch being mechanically coupled to an auxiliary switch in a part which is common for (n l) of the branches, where n is the number of bulbs, and in which in the open state of the first switch the auxiliary switch is closed, and in the closed state of the first switch the auxiliary switch is open.

8. An arrangement as claimed in claim 7, characterized in that a third auxiliary voltage source is connected through a second switch to the second winding of a core added to one of the bulbs, said second winding being present in that branch which connects the terminals of the first direct voltage source and which is free from the auxiliary switch.

Claims

1. An arrangement provided with at least two combustion flash bulbs and with controlled semiconductor rectifiers for successively igniting said bulbs, each bulb being arranged in series with such a controlled semiconductor rectifier and in which each of said series arrangements forms part of a branch connecting two terminals of a first direct voltage source, each of the controlled semiconductor rectifiers being provided with a control circuit, characterized in that a core of a magnetic material having a substantially rectangular hysteresis loop and two stable remanence states is added to each bulb, and that the control circuit of the controlled semiconductor rectifier arranged in series with a bulb is connected to a first winding of the core added to said bulb, a second winding of said core forming part of one of the branches connecting the two terminals of the first direct voltage source together and accommodating one of the other bulbs, a third winding of the core added to a bulb arranged in series with corresponding windings of the cores added to the other bulbs being connected to an auxiliary arrangement for generating a shift pulse.

2. An arrangement as claimed in claim 1, in which the shift pulse auxiliary arrangement is also provided with a core of a magnetic material having a substantially rectangular hysteresis loop and two stable remanence states, characterized in that the latter core has a first winding which is connected through a switching element to a first auxiliary voltage source, the series arrangement of the third windings of the cores added to the bulbs being connected to a second winding of the core of the shift pulse auxiliary arrangement, the branches comprising the bulbs and connecting the two terminals of the first direct voltage source together also accommodating a further winding of the core of the shift pulse auxiliary arrangement.

6. An arrangement as claimed in claim 2 in which the switching element in series with the first winding of the shift pulse auxiliary arrangement is a thyristor, characterized in that the control electrode of said thyristor is connected through a flash contact of a photocamera to the positive terminal of a second direct voltage source.

7. An arrangement as claimed in claim 6, characterized in that a first switch connected in parallel with the flash contact is present between the control electrode of the thyristor and the positive terminal of the second direct voltage source, said first switch being mechanically coupled to an auxiliary switch in a part which is common for (n -1) of the branches, where n is the number of bulbs, and in which in the open state of the first switch the auxiliary switch is closed, and in the closed state of the first switch the auxiliary switch is open.