US3774511A - Contact-less initiation of light emission from photo lamps synchronized with camera operation - Google Patents

Abstract

A magnetically sensitive semiconductor having a plurality of individual magnetically sensitive areas is used to trigger a photoflash lamp in synchronization with shutter operation. A magnetic field is impressed on the individual magnetic areas in time sequense. One is selectively connected to trigger the lamp to provide a selectible time delay for flash operation.

Description

United St tes Patent 1191 Harnden, Jr.

' [111 3,774,511 451 Nov. 27, 1973 CONTACT-LESS lNITlA'lIONOF LIGHT EMISSION FROM PHOTO LAMPS SYNCHRONIZED WITHCAMERA 'r OPERATION 75 lnventorz John D. l-larnden, Jr., Schenectady,

NY. I

[73] Assignee: General Electric Company,

Schenectady-,NY.

22 Filed: 0a. 27, 1969 21 Appl.No.: 869 ,800

52.] U.s.c1..... ..95/11.s11

3,106,080 lO/l963 To az... .Q 95 10 CT 3,220,326 11 1965 Scudder 95 10 CT 3,518,487 6/l970 Tanaka'etal. 315/228 2,161,355 5/1939" Jacobson ..95/11.5 2,336,633 12 1943 Parson,.lr. 95 115 ux 2,382,981 8/1945 Edgertom; 95 115 2,486,010 10 1949 Edgerton ..95 11.5 ux 3,211,069 10/1965 Rixton; ..95 11.5,

- OTHER PUBLICATIONS 1' Hall EffectPut in lC,'Robert Cushman, Edn, N0- vember II, 1968, pp. 87-93.

Primary Examiner-Samuel S. Matthews Assistant Exdminer-Michael L, Gellner Attorney-Frank L. Neuhause'r, Oscar B. Waddell, .Ioseph B. Forman, NormanC. Fulmer and Henry P.

- Truesd'ell v 57 7 ABSTRACT A magnetically sensitive semiconductor having a plurality of individual magnetically sensitive areas is used to trigger a photoflash lamp in synchronization with shutter operation. A magnetic field is impressed on the individual magnetic areas in time sequense.0ne is selectively connected to triggerthe lamp to provide a selectible time delay for flash operation.

' 1 CONTACT-LESS INITIATION OF LIGHT EMISSIONFROM PHOTO LAMPS SYNCHRONIZED "WITH CAMERA OPERATION This'invention relates to a new and improved family of contactless light emission initiation circuits for use in controllingoperation of photolamps employed in The introduction ofthe more complex shutter and variable aperturecontrolj mechanisms in cameras has required theuse of miniaturized electric motors in the cameras to operate such mechanisms. Thisin turn places a demand on the'sources of electric energy (such asbatteries) to supply the increased current necessary to operate such motors. In order to meet this -requirement, and also-maintain-the. size of the battery In practicing the invention, a contact-less photo lamp light emissioninitiation circuit is providedwhich com prises electric supply terminal means for connection to asource of electric energy andto photo lamp means to initiate light emission fromthe photo lamp means upon the establishment of a closed electric current path throughthe-electric supply terminal means, a source of I electric energy and the photo lamp means to be energized. Contact-less photo lamp light emission initiation means are connected in the current path intermediate the photo lamp means and a source of electric energy for controlling the closure of the current pathjto the photo lamp means whereby electrical resistance of films normally built up on conventional switch contacts and vibration, bounce, and chatter due to contact impact are. minimized to thereby assure proper energiza: tion of the photo lamp means. The circuitis completed by means for synchronizing the initiation of light emission from the'photo lamp means with the passage of power source within prescribedlimits for use in hand-;

held cameras, it has proven' necessary to reduce the operating voltage of the energy source'to quite lowvalues on the'order of 1 5 volts. This low voltagerequire-' ment is further dictated by the desire to fabricate the control circuits used in such systems'in mincrominiaturized integrated circuit form since such integrated circuits 'generally are required to beoperated at low voltages. r I

Because of ,the, low voltage requirement, it quite often happens that manycamera photo lamp control circuitsfail to operate reliably. Thishas been due to the buildup of oxidized'and'corrosive,surface filmson the switch contacts of little or minima1ly-used mechanical switches employed in such circuits. To' breakdown such surfacefilms (where they are allowedto buildup) -r equires higher voltage. lf'only 3 volts are availablefrom the primary energy source, (suchas a battery). the

probability of failure-in operation isquite high. To overcome this problem, the present invention was devised.

An additional problem besetting small, hand -held "cameras is the jitter or bounce inducedvinthe camera I by mechanically operable switches comprising apart of the camera control mechanism. The present invention 1 also serves to reduce such jitter, bounce or vibration whereby the chances of obtaininggood picture. quality are enhanced.

It is, therefore, a primary object of-this inventionto provide a family of new and improved contactfless light emission initiation circuits'for use incontrollingoperation'of photo lamps employed inlightingsubjects to be photographed with acamera. i 1

Another object of the invention is to provideflsuch' contact-less photo a lamp light emission initiation circuits which may be fabricated in mierominiaturized integrated circuit form, are capable of reliableoperation' with low voltage electric energy sources, and may be includedasoperating subsystems of an-overall camera control system for controlling light emission synchronously with the controlled exposure of the film plane of the camera. v i

lightthroughthe optic system of a camera with which the photo lamp light'emission initiation circuit is used. In one embodiment of the invention, the photo lamp means may. comprise an array of photo lamps having control circuit means for selectivelylighting desired ones of the photo lamps and the contact-less .photo lamp light emission initiation means initiates the operation of thecontrol circuit means for selectively lighting a-desiredone,of the array of photo lamps. If desired, a

mechanical on-off switch maybe connected in circuit relationship the contact-less photo lamp light emission initiation means for selectively enabling the circuit for operation and preserving theenergy of the low'voltage electric energy source during periods of non-use; however, such mechanical on-off switch is constructed .so that itis readily self-cleaning by involving high forces. *If the photo lamps areof a flashbulb type-,they may bepositioned in the circuit intermediate the source of electric energy. and the contact-less photo lamplightemissioninitiation means so. as to serve as :thelon-oftdswitchinthemanner of an electric fuse.

In another preferred-embodiment of theinvention, an exposure control circuit may be included in -a control systemalong with the 'lightemission initiation circuit for controlling the extent of exposure of the film plane ofthecamerato a subjectbeing photographed in conjunction with light emitted by the photo lamp means, and such-a system includes means for synchro nizing operationof the exposurecontrol'circuit with theoperatiojn of the contact-less photolamp light emission initiation=meansi In a still further arrangement according to the-invention, the photo lamp means em-v 1 ployed may. comprisean array of photo lamps having control circuit-means for selectively lighting desired ones of the photo lamps and 'thecontact-less photo v lamp light emission initiationmeans initiatesoperation ofathe'controlcircuit means for selectivelylighting a desired one of the may" of photo lamps. ln'all uch cameracontrol system arrangements, the circuit components preferably are fabricated in microminiaturized f integrated circuit form.

- According to'the particular applications in mind, the

.contact-less'photolarnp light initiationmeans may be magnetically operated, it may be radiant energy operated either by light or alpha particle radiation or the like, or it may-be pressure responsive. Several different forms. of these basically different contact-less photo lamp light emission initiation means are disclosed.

' Other objects, features and many of the attendant ad-. vantages of thisinvention will be appreciated more readily as the same becomes better understood by reference to the following detailed description when considered in connection with the accompanying drawings, wherein like parts in each of the several figures are identified by the same reference character v and wherein:

FIG. l'is a schematic circuit diagram of one form of a new'and improved photo lamp lightemission initiation'ciruit constructed in accordance with the invention; 1

FIG. 2 is a schematic circuit diagram of still another form of a contact-less light emission initiation circuit according to the invention and which employs a pres sure responsive initiation means;

FIG. 3 is a schematic functional diagram illustrating one form of mechanizing the circuit arrangement depicted in FIG. 2; I 1

FIG. 4 is a schematic circuit diagram of a magnetic sensitive contact-less photo lamp light emission initiation circuit constructed in accordance with the invention;'

FIG. 5 is a schematic circuit diagram of still another form of magnetic sensitive contact-less emission initiation circuit employing a magnetic sensitive diode;

FIG. 6 is apartial perspective view of a portion of a camera shutter mechanism illustrating the manner in which such mechanism can be modified to include either a permanent magnet or a light opening for contactless initiation of a magnetic sensitive diode or a light sensitive diode;

FIG. 7 is a schematic circuit diagram of still another control of the exposure of the film plane of a camera;

FIG. 15 isa schematic circuit diagram of an embodiment of the invention employing a light emitting diode as part of the contact-less light emission initiation means;

FIG. 16 is a schematic circuit diagram of a. different form of the contact-less light emission initiation circuit employing a light emitting diode and light activated silicon control rectifier to initiate light emission in a contact-less manner; s

FIG. 17 is a schematic circuit diagram of still a third form of contact-less light emission initiation circuit employing a light emitting diode and including a capacitor for conserving energy of the low voltage electric energy source employed for circuit energization purposes; and

FIG. 18 isa schematic circuit diagram of a modification of the circuit of FIG. 4.

FIG. 1 is a schematic circuit, diagram of a contact-less photo lamp'light emission initiation circuit constructed in accordance with the invention, and which employs a pressure sensitivestrain gauge element shown at 11 as a contact-lessphoto lamp light emission initiation means. The pressure sensitive element 11 may comprise any known form of pressure or strain sensitive device which changes its electrical resistance in response to the application of a pressure or strain to its pressure sensitive area. The pressure sensitive element 1 l is conform of contact-less light emission initiation circuit according to the invention which employs a magnetic sensitive I-Iall element and amplifier arrangement;

FIG. 8. is a functional block diagram of themagnetic sensitive Hall element and amplifier employed in the I circuit arrangement of FIG. 7;

ement that can be employed to provide certain delay functions in the operationof a light emission initiation circuit employing such' an element;

FIG. 1 1 is a series of characteristic curves illustrating the intensity of light emitted vs. time characteristic of nected in series circuit relationship with a load resistor 12 across a'pair of power supply terminals 13 and 14 that in turn are adapted to be.v connected across a source of electric energy 15. The source of electric energy 15 may comprise any known portable source of electric energy but preferably comprises a low voltage battery having a terminal output voltage of approximately 3 volts or less and a short circuit current of about 2 amperes, although the circuit is in no way restricted to use only with energy. sources of this voltage rating. With the circuit thus comprised, a conventional mechanically operable on-off. switch 16 is included in the series circuit comprising pressure sensitive element 11. and load resistor -12.'For areason to be explained I more fully hereinafter, the on-ofi' switch 16, if needed, I should be located in a position so that its variable on a light emission initiation circuit employing the circuit FIG. 14 is a functional block diagram of still different and improved camera control system a'ccording'to the invention which provides synchronized contact-less light emission initiation, control over the flashing of selected ones of an arrayof photo lamps, and electronic resistance would have minimum effect. As an alternative the switch 16 can be eliminated and a switch shown in dotted outline form could be included in the circuit in place of switch 16. In either case, higher forces and self cleaning result as compared with norm shutter operated contacts at low level. r In additionto the above-mentioned circuit components, the power supply terminals 13 and 14 also are connected across a series circuit branch formed by a photo lamp means comprising a socket or a plurality of sockets for receiving thebase of a conventional photo lamp'in the photo lamp means is connected in series circuit relationship with the load terminals of a gate operated semiconductor switching means 18. The photo lamp means may comprise a conventional bayonet type receptaclefor receiving a single photo lamp flashbulb such as the M5 or M2 flashbulbs or the A G-l flashbulb manufactured and sold by the Photo Lamp Department of the General Electric Company or some similar photo lamp. The photo lamp means also may comprise the or the photo lampmeans 17 may even comprise an'integrated circuit type of lighting control shown in dotted outline format 19 for selectively controllingjthe lighting or flashing of desired onesof an array of photo lamps such as shown in dotted outline form at 21a, 21b, etc. Thus, it will be appreciated that thephoto lamp means 17 employed in the embodiment of the invention shown in FIG. 1 as well as in other'embodiments of the invention to be described hereinafter, maycomprise any one of the above-listed devices and/or the receptacles or sockets for receiving such devices. It is to be understood, therefore, that while only a single photo lamp 17 will be shown in the remaining embodiments of the invention disclosed herein, such depiction is in-' tended to include any of the above-mentioned photo lamp means and similar devices. I

The gate control semiconductor switching means 18. may comprise a conventional gate control silicon con-.

trolled rectifier (SCR), a silicon. unilateral. switch SUS), a programmable unijunction transistor (PUT),

a silicon bilateral switch (SBS), a complementary uni- I on-off switch contacts 16 being closed and the applica tion' of a sharp striking blow or other means for suddenly increasing the pressureon the pressure sensitive surface of element 11, the current'flowing through the load resistor 12 will be sharply increased. The coupling capacitor 22 operates to convert the sharp increase in voltage appearing across the load resistor l2to a gating current applied to the gating electrode of the semiconductor switching device 18 to render it conductive and thereby supply a light'ernission initiating current'flow through the photo lamp means l7.

As was notedearlier, the on-ofi' switch 16 is physically located in a preferred position such that its switch thereafter supplies the main light flash initiating cur- I rent through the photo lamp 17. I If the photo-lamp 17 comprises a conventional, ex-

. pandable photo flash lamp of the General Electric M-2 type, it will require about 1 ampere of current at 0.7 of a volt to assure reliable flashing. With the circuit arrangement shown in FIG. 1, flashing current and voltage of this magnitude is assured since with the semiconductor switching device 18 gated on in its conducting condition the forward voltage drop through the device is only'a fraction of a volt. From a consideration of the circuit shown in FIG. I, particularly where the on-off switch 16 is included in the circuit branch with element 11 and load resistor 12'and is not connected intermediate the low voltage battery source 15 and the photo lamp 17, substantially the full voltage of the source 15 minus only the forward drop of the semiconductor switching device 18 is applied across photo lamp 17 to assure reliable flashing of the photo lamp. It should be noted that with either arrangement employing the onoff switch 16, or the alternative arrangement shown in'dotted outline form at 716a, it is neces- -sary that the switch contacts be readily accessible for of the gate controlled semiconductor switching device contacts do not carry full currents and low contactresistance is not a'requirernent. Also,'since either 16 or 16a are not tied in with the shutter they are more suc-'.

cessfully cleaned by the unskilled; This arrangement is in contrast to many prior art devices wherein mechanically operable, on-off switch contacts are mounted and operate synchronously with theshutter mechanism of the camera, etc., and must be located in a position within the camera so as not to be accessible for cleaning. Assuming therefore that the switch contacts 16 are cleaned-so as not to constitute a considerable increase cleaning so asto minimize any voltage drop across the switch contacts. l

It may be necessary to include a mechanicalon-off switch in the contact-less light emission initiation circuit shown in FIG. 1 due to the fact-that withoutsuch I a switch, current could continuously flow through the pressure sensitive resistance element'll' and load resistor 12 and ultimately bleed off the energy of the battery source '15. However, the high foff resistance of semiconductor 18, and certain pressure sensors 11 could result in leakages less than the normal battery leakages and thus would result in life approaching shelf life. In-

all events, it willbe seen that the electric current flow required to initiate light emission from the photo lamp is developed internally through intemal operation of the pressure sensitive resistor element vll so that only a minute current flow will suffice to initiate conduction 18. Because of this internal generation or development of the required light flash initiating current, and the fact that such current is not required to puncture an'ex- ,ternal oxidized or other corrosively coated surface film formed on a set of switch contacts, the circuit arrangement can be said to be contact-less in naturein that it possesses less vulnerable contact resistance than previ- 'ously available light emission initiation circuits;

Pressure transistors with high ofi-resistances are presently more common than 2 terminal pressure de- 1 vices with similar properties. Thus, an arrangement such as shown in FIG. 2 of the drawings may be em- I ployed to'avoid all switches. The circuit arrangement shown in FIG. 2 is comprised by a contact-less photo lamp light emission initiation means 25 connected in series circuit relationship with a load resistor 12 across in resistance, and ifa low voltage batterysource 15 is employed having a voltage on the ord r of 3 volts, sufficient current will be supplied through the load resistor 12 to gate on the SCR or other gate-controlled semi conductor switching device l8. For this purpose, some thing on the order of 20 200 microamperes of gating current must be supplied to the gate electrode of the switching device 18. It will be appreciated, therefore,

, that only a minute amount of current is required to trigger on the gate control switching device '18 which the power supply terminals 13 and 14 which are designed to be connected across the load terminals of a low voltage battery source 15. The contact-less photo lamp light emission initiation means 25 comprises a pressure sensitive semiconductor device such as piezoelectric pressure transistor similar to that offered for sale by the Stow Laboratories of Stow, Mass, announced in the Electronics Magazine, January 23, I967 issue. The pressure sensitive transistor 25'includes a pressure sensitive area 36 that is exposed to a small cap The juncture of the load resistor 12 and pressure sen-- sitive transistor is connected to the control gate of a semiconductor switching element 18 such as an SCR, SUS, etc., that in turn has its load terminals connected in series circuit relationship with the receptacle for re ceiving a photo lamp means 17 which of course may comprise either a single photo flash lamp or similar de receptacle itself is external of the camera or other housing for the light emission initiating circuit, j and hence can be cleaned readily by auser of the equipment should-the abrasive cleaning action of the insertion and removal of the photo flash lamp not prove sufficient. For these reasons the contact-less photo lamp light emission initiation circuit shown in FIG. 2 is highly reliable in operation even with very low voltage battery sources.- 7

FIG. 3A of the drawings illustrates one form of a mechanical actuating mechanism for applying pressure or stress to a stress'sensitive area of the semiconductor element 25. In this arrangement, a pushbutton 31 foracvice. It is necessary in the circuit of FIG. 2, however,

that the photo lamp means 17 be of the photo flash type which burns out or open-circuits upon being flashed. With this arrangement, thephoto flash lamp 17 will function as an on-off switch in the manner of a fuse to open the circuit connection through the load terminals of the gate control semiconductor switch 18 after being flashed. This is important since the gate controlled semiconductor 18 is of the thyristor type which once being gated into conduction remains in conduction until the current flowing through the device hasbeen,

reduced below a minimum holding value. Upon this 00,-

casion, the device will re-assume its blocking condition u'ntil again gated on by the application of a gating signal to its gating electrode. Thus, it will be seen that; the

With the circuit arrangement shown in FIG. 2, it i should be noted that with respect to the gating on circuit element comprised by the contact-less, pressure sensitive transistor 25, load resistor 12 and low voltage 1 battery source 15, there are no mechanical on-off switch contacts in this circuit branch.The light emission initiating switching action takes'place internally in the pressure sensitive semiconductor switching device 25 upon the cap or anvil 26 contacting the pressure sensitive area of the semiconductor device 25 as shown' in FIG. 3. Thus, the light flash emission initiating current need not'puncture or pass through a .high resistance film in order to develop the desired light emission initiating gating on current pulse to be supplied to the control gate of the semiconductor switching device 18. Similarly, the switching device 18 operates only through intemally'protected current paths to supply the'light flash initiating current to the input terminals of the photo flash lamp 17. The only contact surfaces in the circuit arethose provided by the socket or receptacle in which the photo flash lamp 17 is secured. These contact surfaces normally will be subjected to a cleaning action by reason of the insertion and removal .of the photo flash lamp base into theireceptacle under high force levels. Additionally, it should be noted that the tuating a camera associated with the light emission-initiation circuit, is attached to a lever arm 32 pivoted at a point 33 against the action of a return spring 34. An anvil 35 is formed on one surface of the lever arm 32 and hasthe cap 26 attached thereto at a point directly opposite the pressure sensitive surface 36 of the pressure sensitive semiconductor element 25. The end of lever arm 32 operates against a cam surface 37 of a shutter 38 which normally closes the aperture shown at 39 used to expose the film plane of the camera. Upon the pushbutton 31 and lever arm 32 being depressed by auser of the camera, the anvil 35 and cap 26 will be broughtinto contact and will apply stress or pressure to the pressure sensitive area of the semiconductor de vice 25 thereby initiating current flow through the device and hence photo lamp :17 of FIG. 2 in the manner previously described. Simultaneously with this action, the cam surface 37 will cause the shutter 38 to bepivoted to the position shown in dotted outline form thereby exposing the aperture 39 and hence the film plane of the camera.

'The mechanical angular relationship of the opening of shutter 38 to the point where the cap 26 on anvil 35 strikes pressure sensitive transistor 25 is such that the opening of aperture 39 occurs after a short delay period related to the time required for the flash bulb to emit its peak intensity of light. This relationship is depicted in FIG. 3B of the drawings wherein the percent opening of the aperture 39 is plotted against time. From a review of FIG. 3B it will be seen that the percent opening of aperture 39 goes from 0 value to a I maximum value after'a period of about 10 milliseconds following depression of the pushbutton 31. The curve shown in FIG. 38 also could be employed to illustrate the emission of light characteristics of the photo flashbulb where the intensity of light is plotted as the ordinate and the time required to emit a given amount of light is plotted as the abscissa. It will be seen that the mechanical relationship of the opening of the aperture v 39 is designed to coincide substantially with the maximum light intensity emission of the photo flash lamp 17 with which the circuit is designed to be used. It might also be noted that while in FIG. 3 the cap 26 is shown as being mounted on anvil35, the mounting of the cap v on the semiconductor surface 36, orother similar alternatives also could readily be achieved. a

' FIG. 4 of the drawings isa schematic illustration of still another form of contact-less photo lamp light emission initiation circuit employing a magnetic sensitive diode 41 as the contact-less photo lamp light emission initiation means. The magnetic sensitive'diode 41 is connected in series circuit relationship with a load resister 12 across thepower supply terminals 13 and 14 and through on-off switch 16 to the electric energy v 9 source 15 which may comprise a low voltage battery of about 3 volts. The magnetic sensitive diode 4lmay be similar to the one manufactured and sold by; the Sony tivev Hall element or other magnetic sensitive semiconductor device could be employed in place of the diode 41 as will be described more fully hereinafter. Similar to earlier described circuits, the juncture of the magnetic sensitive diode 41 and load resistor 12 is coupled through a coupling capacitor 22 to the control gate of the semiconductor switching device 18 such as an SCR, SUS, etc. The load terminals of the switching device 18 in turn are connected in series with the photo lamp means 17 for selective energization in themanner described hereinafter.

A rotatable shutterplate 42 which is spring biased to rotate in a counterclockwise direction as shown by the arrow 'includes an aperture opening shown at 43 which upon rotation into alignmentwith the aperture orpassageway providing an opticpath to thefilm plane of a camera (shown at 44), will'operate to'expose the film plane to a subject being photographed. The shutter plate 42 can be pre-wound be means of a trigger mech anism (not shown) by an operator of the camera and is prevented from unwinding by a stop 45 formed on its periphery. In the pre-wound condition, the stop 45 is engaged by the .end of a release lever arm 46 that in turn is actuated by a pushbutton 47. Upon the pushbutton" 47 being depressed against the action of .a return spring 48, the end of lever arm 46 allows the rotatable shutter member 42 to be rotated in the direction shown bythe arrow. t

The rotatable shutter plate 42 also includes a permanent magnet shown at 49 which is mounted on its periphery and which is adapted to influence or magnetically permeatethe magnetically sensitive area of the magnetically sensitive switching element 41 upon being rotated in the previously described manner. It is desir-, able that themagnetic energization of the magnetically sensitive semiconductor diode 41' take place slightly in advance of the aperture opening 43 becoming aligned ate in the manner of a fuse. However, for such anarrangement, the photo lamp17 would have to be of a filament type which will allow sufiicient trickle current to flow through its filament to render the diode 41 conductive. v

After conditioning the circuit of, FIG. 4, an operator of the-camera is then ready to trip the camera for pictur'etak ingpurposes Upon this occasion, the pushbutton 47 is depressed thereby releasing the rotatable shutter 42 in the above briefly described manner. This results in aligning the magnetic field of the pennanent magnet 49 (at least instantaneously by reason of the rotational scanning of the field of the permanent magnet past the magnetically sensitive semiconductor diode 41) so as to trigger the diode 41 intoconduction. This results in the production of a current pulse in the gateemitter circuit of SCR 18'by reason of the co-action of the load resistor 12 and coupling capacitor 22 and triggers the semiconductor switch 18 into conduction thereby igniting or flashing the photo lamp 17. As previouslystated by reason of their relative angular location on rotatable shutter 42, flashing of the photo lamp 17 is initiated somewhat in advance of the aperture opening 43 exposing theaperture 44 and hence film plane of the camera so that such exposure coincides substantially with the maximum or peak intensity of the light emitted by the photo lamp 17..It will be appreciated, therefore, that the resulting light flash initiation is derived through internal action of the magnetically sensitive semiconductor, diode 41 without requiring that the low voltage. source 15 provide sufficient energy to punch through anyoxidized or corrosive surface film with the aperture 44 so that upon the latter occurrence,

the light emitted by the photo lamp 17 has reached substantially its peak intensity. This can be accomplished by appropriate design of the angular location of the permanent magnet 49 on'therotatableshutter plate 42 relative to the positions of the aperture opening 43 on theshutter plate and the aperture 44 which is of course located on -a different part of the camera and is in a fixed position relative to the rotatable. shutter plate 42.

In operation, the circuit of FIG. 4 functions in the fol- I lowing mannerqln this description, it is assumed that an operator has inserted a photo lamp 17 in the socket designed to receive such photo lamp and has pre-wound or cocked the camera so as .to condition the rotatable shutter plate42 to be rotated through theaction of a pre-wound spring (notshown) in the manner described, I above. If a mechanical on-off switch 16 is located in the .circuit as indicated, it would then be closed to condition the circuit for operation. However, it should be noted that the circuit could be modified to eliminate the on-off switch 16 by placement of the photo lamp 17 the 'on-off switch 16 (sould it be used as shown in FIG.

4) can be designedto be selfcleaning and operable at high force levels. Thus, it will be appreciated that the magnetically sensitive diode 41 constitutes another 7 fonn'ofconta'ct-l essphoto lamp light emission initiation means according to the invention.

- FIG. 50f the drawings is a schematic illustration, of

a contact-less light emissioninitiation circuit which has been constructed using the trigger mechanism (shown in FIG. 6) along with-the other components of an Eastman Kodak model 134 lnstarnatic" camera. This particular camera includes an electro-optic exposure contr'ol'shown at 51 which operates in conjunction with a light source 52 through the medium of anintermediate.

switch contact 53 that is closed initially upon the oper- ,atorof the camera depressing the pushbutton 47 against the action of a return spring 48. The closing of the intermediateswitch contact 53 onto a switchconthe exposure control circuit 51 and to a light source 52' tact 54 formed on the pivoted lever arm 55. (with the pushbutton 47 in the depressed position), allows electric current from the electric energy source 15 (which may comprisea low voltage battery source) to flow to to indicate to theuser of the camera that the battery source 15 is working, and that the exposure control 51 r is energized. The exposure control 51 then operates autr'ol circuit 51 the pushbutton 47 will continue its'travel tomatically inthe manner of a photometer to set the aperture opening of the camera in accordance with ambient lighting conditions. I

Subsequent to the energization of the exposure condownwardly so as to close the intermediate switch contact 53 onto a third switch contact 56. Contact 56 includes an extension 57 that operates against the end 46a of a centrally pivoted lever arm 46. The remaining end of the centrally pivoted lever arm 46 operates to stop the rotation of a rotatable shutter member 42 as was described previously in connection with FIG. 4 of the drawings. The rotatable shutter member 42 is acted upon by a pro-wound spring (not shown) which tends to rotate the shutter member 42 counterclockwise in the direction of the arrow. Mounted on the rotatable shutter member 42 is a permanent magnet 49 and an aperture opening 43 is formed in the member for exposing the aperture 44 shown in dotted outline form to thereby expose the film plane of the camera. This portion of the circuit operates in precisely the same man net as the embodiment shown in FIG. 4.

Upon an operator of the camera placing the camera in condition for the taking of a picture, he will have pre-wound the spring that drives the rotatable shutter member 42, inserted an unused photo flashbulb 17 in the socket for receiving the same and properly lined up the camera forthe taking of a picture. Thereafter; upon depressing the pushbutton 47, the following sequence of operations will occur. First, during the initial portion of the downward travel of the free end of the pivoted lever arm 55, the switch contacts 54 and 53 will close soas to energize the'exposure control 51 and the indicause the extension 57 to rotate the end 46aof lever arm 46 downwardly in a counterclockwise direction so as to release the end 46 from the stop 45. The prewound spring will rotate the shutter member 42 in a counterclockwise direction shown by the arrow so asto align the magnetic field of the magnet 49with the magnetically sensitive, contact-less, photo lamp light emission initiation means comprised by the magnetically sensitive diode 41. This results in the production of a gating-on current in the gate-emitter of the semiconductor switch means 18 causing it to be rendered conductive and to supply a light emission initiating current to the filament, fibrous material, gaseous material, or

other light emission substance in the photo lamp 17. As I stated previously, the relative positions of the, per'ma nent magnet 49 and the aperture opening 43 on the ro-' tatable shutter member 42 are predesigned to allow coincidence of peak or maximum light emission with the exposure of the aperture or other optic path opening to being advanced, it will automatically cock the trigger plate 69 into its preset or wound condition shown in cludes a shutter plate 61 which is rotatably suspended v by a pivot 63 over an aperture of the camera shown at 44 formed in a back supporting plate 62. The shutter 12 plate 61 includes a spring tensioning arm 64 which is acted upon by a wire tension spring 65 supported between the pivot 63, the tension arm 64 and a pin 66 secured to the back supporting plate 62. The springis arranged such that in its normal, quiescent condition, the

shutter plate 61 is supported in the position shown 'inv supporting plate 62. The extension supporting surface 68 has rotatably mounted on it a trigger plate 69 having an amplifying am 71 which is designed to engage the trigger arm 67 of the shutter plate 61 and to rotate it in a clockwise direction from its quiescent position shown in FIG. 6. When the trigger arm 67 is rotated clockwise by the amplifying arm 71, aperture 44 will be exposed allowing the image of an object being viewed by the camera to be projected through the optical path provided by the aperture 44 to the film plane of the camera, in a well-known manner. To assure proper operator controlof the opening of the shutter plate 61, the trigger plate 69 is designed to be'rotated clockwise from the position in which it is shown in FIG. 6 to the dotted line position shown. When this. prewound or cocked, the amplifying arm 71 is engaged behind a release pin 72 formed on a cantilever arm 73 pivotably supported at 74 and tensioned in an upward position by the action of a bias spring 75. The bias spring 75'holds the cantilever arm 73 in its upward position so that the stop 72 prevents the amplifier 'arm 71 from rotating into engagement with the trigger 67 of shutter plate 61. The trigger plate 69 is rotated into its cocked or set condition by means of a conventional film advance and cocking mechanism (not shown) having a wiper arm shown at 76 that engages an upwardly ex tending tab 77 formed on the trigger plate 69. Trigger plate 69 is rotated around the pivot point 78 against the action ofa hair spring shown at 79 supported between a pin 81 secured to the surface 68, or some similar fixed surface on the housing of the camera, and a pin 82 secured on the trigger plate 69. I

-With the above arrangement, upon the camera film dotted outline form against the action of the hair spring 79 which tends to return the trigger plate to its quiescent condition shown in solid lines in FIG.-6. The magnetic diode shown at 41 in FIG. 5 is mounted on the camera housing in a position closely adjacent the trigger plate 69 and a permanent magnet 49 is secured to the trigger plate 69 in a' position such that its magnetic field will sweep past and act upon the magnetic sensitive diode 41 upon the trigger plate 69 traveling from its cocked or wound position shown in dottedoutline form'to its quiescent condition shown in solid form in mum light intensity produced by photolamp 17 is r l3 achieved substantially concurrently with the full opening of the aperture 44 by theshutter plate 61 y In operation, it will be seenthat upon the film of the camera being advanced to a new, unused portion, the film advance and cocking mechanism automatically will cock the trigger plate 69 to its prewound condition shown in dotted outline form. In moving to this condition, the amplifying arm 71 will be enabled to ride over the tapered or curved surfaces of the release pin 72 and trigger lever arm 67. A stop or pin 83 prevents the shut ter plate 61..from being rotated counterclockwise to a 7 position sufficient to expose the aperture 44 during the cocking or film advance operation. There, the amplifying arm 71 will be blocked in back of release pin 72 until such time that the operator of the "camera depresses the pushbutton 47. Atthis point, the amplifying arm is swept to its solid line position by the action of hair spring 79 thereby rotating lever arm 67 and shutter plate 61 in a clockwise direction, triggering the magnetic sensitive diode 41 and exposing the aperture opening 44 in the above-described manner.

I plifier 88 will be triggered into conduction at a point,

43 is formed in the rotatable member93 at an angular position such that it will coincide with the aperture or other optical coupling path, to thefilm plane of the camera such as is sho'wn in dotted outline form at 44. Here, again, the'arrangement is such that the magneti cally sensitive Hall element and integrated circuit amsuch that maximum light intensity is produced bythe photo lamp means 17 substantially simultaneously with the exposure of the aperture 44 by ap'erture opening 43. However, because no large mass in the form of a I permanent magnet is attached to a'movable part, the

dynamic performance of the apparatus can be im- The embodiment of the invention shown in FIG. 6

possesses certain undesirable characteristics in that it requires the 'use of a relatively high mass permanent magnet 49 to be mounted upon the movable trigger plate 69. This requirement in'itself tends to limit the speed of response of the overall trigger mechanism and adversely affects its performance. To avoid this possible limitation, an arrangement such as shownin FIG. 7 may be employed. In FIG. 7 a photo lamp means 17 is designed to be energized from'a'low voltage source of 7 electric: energy comprised bya battery l5 .through power supply terminals 13 and 14 and the selective switching action of a contact-less, magnetic sensitive,

integrated circuit Hall element and amplifiershown at 88. The construction and operation of the magnetic sensitive Hall element and integrated circuit amplifier 88 will be described more fully hereinafter in connection with FIG. 8 of the drawings. However, for the pur-, pose of the present description, it is believed to be sufficient to point out that this element is magnetically sensitive and can be designed to provide a sharp output current pulse in response to the application of a magnetic field to the magnetic sensitive areas of the element. i

A permanent magnet 89 having a pair of magnetically permeable legs 9l and 92 positioned with the legs 91 and 92 straddling the magnetically senstive Hall element and amplifier 88. A magnetically permeable rotatable member 93 which may be in the form of a very thin disc of magnetically permeable material, is secured I so that its periphery normallyis disposed opposite the ends of the legs 91 and 92. While thus arranged, the rotatable member 93 serves to short circuit or bypass the lines of magnetic flux from the ends of the legs 91 and 92 around the magnetically sensitive Hall element and integrated circuit amplifier 88. Aslot shown at 94 is FIG. 4 and other figures of the drawings. An aperture proved. v

FIG. 8 is a functional block diagram of the construction of the integrated "circuit, magnetically sensitive E Hall element and integrated circuit amplifier shown at 88 in FIG. 7. The Hall element employed in this structure, is shown at l0l and may comprise a combined metal oxide surface semiconductor Hall element and amplifier of the type described in US. Pat. No. 3,524,997, issued Aug. 18, 1970, for a Monolithic Integrated Phase Control CircuitZ John D. Harnden, Jr., et'. al., inventors, and assigned to the assignee of the present invention. The Hall element is a well-known magnetically sensitive device having a conducting channel or inversion layer extending between a source and drain electrode. Upon a strong magnetic field on the orderofabout 2 kilogauss beingapplied perpendicular to the-current flow of the device,it produces through the medium of the well known Hall Effect, a voltage component which is mutually perpendicular-to both the current flow and the'magnetic field, and is proportional to the product of the. current and the magnetic field. This output voltage is supplied to a suitable signal-shaping circuit 102 which may comprise a field effect transistor. amplifier circuit whose output in turn supplies a power amplifier stage 103. The power amplifier stage 103 may itself comprise a device such as a silicon control rectifier (SCR), a PUT, a SUS, or other known power amplifier device and may be directly connected in circuit relationship with the photo lamp means 17 andbattery source 15 for controlling electric current flow through the photo lamp means 17 shown in FIG. 7. All of the elements 101, 102 and 103 of the overall circuit structure 88may be fabricated in mono lithic integrated circuit form so as to be readily mounted within the housing of a hand-held camera. For

a more detailed description of the construction and operation of the Hall element magnetic sensor and integrated circuit amplifier structure, reference is made to the above-identified U.S. Pat. No. 3,524,997.

FIG. 9 is a schematic illustration of still another form of magnetically triggered, contact-less, light emission initiation control circuit constructed in accordance with the invention. In the embodiment of the invention shown in FIG. 9, a magnetically sensitive semiconductor switch element shown at l05controls the initiation of light emission from a photo lamp means 17in the manner described above. For example, the semiconductor switch element 105 may comprise either a magnetically sensitive diode, a magnetically sensitive transistor, such as that described in (LS. Pat. No. 3,389,230, or a magnetically sensitive Hall element together with associated integrated circuit amplifier elements. A rotatable permanent magnet trigger member shown at 106 is positioned over the semiconductor switch element 105 and includes an aperture opening 43 that is rotated into alignment with an aperture shown in dotted outline form at 44, upon the rotatable member 106 being rotated in a counterclockwise direction as shown by the arrows. The releasemechanisrns and spring drive mechanism forrotating member 106 are not shown for purposes of simplifying the description. The rotatable trigger member 106 includes apole piece 107 which upon being aligned with a coacting pole piece 108 disposed adjacent the semiconductor switch element 105, causes the semiconductor switch element to be triggered to its conducting condition as described previously. In the arrangement shown in FIG. 9, however, the linear position of pole piece 108 is physically adjustable to different locations such as shown in dotted outline form at 108a whereby the particular point at which the semiconductor switch element 105 is triggered into conduction relative to the angular position of the aperture 43 with respect to the aperture 44, can be adjusted physically by a user of the flash initiation control circuit. This can be achieved by a simple sliding support for the pole piece 108 which is calibrated in terms of time delay so as to achieve either minimum or maximum delay of the light emission relative to the alignment of the aperture opening 43 over the aperture 44. By this means, the user of the camera can control to a greater degree the timing relation between the pulsed maximum intensity light out put from the photo lamp means 17 relative tothe opening of the aperture of the camera. 7

FIGS. 10 and 11 of the drawings illustrate still another form of the invention wherein by suitable fabrication of the semiconductor switch element employed in the arrangement of FIG. 9, and proper disposition of several magnetically sensitive areas on a semiconductor substrate to form a multiple semiconductor switch element such as shown at 111, a selectable built-in time delay can be obtained wherein an operator of a camera can by appropriate choice of an output terminal, achieve any one of a plurality of different time delays relative to the opening of the aperture of the camera. For example, if a semiconductor switch element such as111 has formed, on its substrate three different magnetically sensitive switch areas 112, 113, 114, with each respective area having its own output terminal T is illustrated in FIG. 11 wherein the light outputfrom a photo lamp triggered by respective ones of the output terminals T T and T is plotted vs. time. It will beseen in FIG. 1 1 that if the operator connects the photo lamp means 17 to the output terminal T the maximum intensity light flash will be produced only about 1 millisecond in advance of the opening of the aperture 44 by aperture opening 43. For certain types of pictures, under certain conditions, this kind of exposure is desirable. However, for other conditions, it may be desirable to connect the photo lamp means 17 to the output terminal T whereby maximum -,light intensity from the photo lamp would be produced some 2 milli-' seconds in advance of the opening of the camera aperture. Similarly, by connecting the photo lamp means 17 to the output terminal T; a full lOmillisecond delay can be obtained. The selection of the delay can be made by the, operator in advance of taking the picture, and is a fixed highly predictable, reliable time delay since there are .no physical adjustments that have to be madeby. the operator other than connecting the photo lamp means to the desired output terminal T 'T T T etc. It should be noted that the particular time delays described are for purpose of illustration only and may be the embodiment of the invention shown inFIG. 12, a 7

photo lamp means 17 isdesign'ed to be flashed by controlling electric current flow through the photo lamp means 17 from a source ofelectric energy such as 15.

For this purpose, a magnetically sensitive semiconductor switch element 111 is provided having a first mag- T and T then the output flash initiating signal pulses obtained from each of these areas will have different time delays if the switch element 111 is included in a physical circuit arrangement such as shown in FIG. 9.,

Thus, with a semiconductor switch element such as 1 11, no physically movable parts are required to obtain different timed output signal pulses for producing light flashes in different time sequence relative to the open ing of the aperture of the camera.

For example, assuming the switch element 111 were inserted physically in the circuit of FIG. 9, it will be seen that as the pole piece 107 is being rotated counterclockwise sequentially scans across the magnetically sensitive switch areas 112, '1 13, 114-in that order. Thus it will be-seen that an electric output signal pulse will 'be produced at 112 some 10 milliseconds (for examnetically sensitiveswitch area 112 connected to control electric current flow through the photo lamp means 17.

.A second magnetically sensitive semiconductor switch area 1 13 is formed on element 111 and is connected to control energization or actuation of a relay winding 1 15 that then in turn controls release, or actuation of a rotatable shutter wheel 42 having an aperture opening '43 thereinfor controlling exposure of the film plane of i the camera through the aperture 44' shown indotted outline form. This arrangement 'may be similar to that employedv on bellows type cameras used for better quality picture taking by professional photographers. With such cameras, it is-necessary to provide some remote control means for synchronizing operation of the shuttermechanism located at the end of the bellows when it is in its expanded conditiomwith the emission .of light from a photo lamp such as 17.

inwardly from the position shown due to thecontinued depression of the'pushbutton 47, the strength of the magnetic field influencing the magnetically sensitive switch area 113 will become sufficiently strongto ren-,

der this switch area conductive. Uponthis occurrence, the relay winding 112 controlling the shutter member 42 will be actuated to thereby obtain a synchronized of FIGS. 4 -12. The magnetic light emission initiation circuitserves to control light emitted from alight source 122.that can comprise 'a-single photo lamp, an;

array of photo lamps, a flash cube or the like, which emits light when energized from asuitable energy source such as 123 under the control of the magnetically sensitive, contact-less, light emission initiation circuit 121. The energy source 123 may comprise a low voltage battery source, a piezoelectric generator, a

spring wound generator, or other type of knownsmall power source. Operation of the magnetically sensitive light emission initiation circuit 121 is under the control of a pushbutton switch 124 that depresses a permanent magnet 125 so as to cause its magnetic fieldjto influence the magnetically sensitive area of theinitiation control circuit 121. This occurs upon the Ipushbutton 124 being depressed so as to bring the permanent magnet 125 from the solid line position shown in FIG. 3

down to the first dotted lineposition shown at 125a. Upon, this occurrence, the magnetically sensitive light emission initiation control circuit l2l will function in the previously described manner to cause the photo lamp means122 to be energiz'ed,.and emitlightfor lightinga subject to bephotographed;

Further depression of the pushbutton 124 will cause the permanent magnet 125 to be moved to its second position shown in dotted outlineformat 125b where its magnetic fieldwill influence the magnetic sensitive sur- 18 trolled exposure element 127 reference is made to an article entitled GMO A New Optical Material by Professor Terutaro' Nakamura of the-University of 1 Tokyo appearing in Technocrat Magazine, vol. 2, No. 5,,

shown at 121 and may be constructed according toany 13A of the drawings.

1969, pages 44-46. The device comprises a GMO crystal having ferro-electric properties such that it can be made transparent to light upon the application of a control. electricfield to its terminals. For a more detailed description of this property, reference is made to the above-identified article. The device does constitute, however, a solid state semiconductor type of device so that it allows substantially the complete camera control system to be fabricated in accordance with in.

tegrated circuit manufacturing techniques. The device in its unexcited state will serve to block all light passage between the lens 128 and the filmplane 129.'I-Iowever, upon appropriate excitation by an applied direct current electricfield, thedevice can berendered sufficiently light'transmissive to form an image of the subject being photographed on the film plane 129. By controlling the time .duration of this direct current exciting field, an appropriate photograph of the image can be obtained. The time duration of the exposure can of course be'controlled by appropriate design of the magnetic initiation andJconversion circuit 126 to provide the desired exposure time period as depicted in FIG.

In, operation, .assuming'that the camera has been appropriately loaded with unused-film, and unused flashbulbs, and has been aligned on a subject to be photographed bya user of the camera, a picturecan be recorded in accordance withthe following sequence. De-.

' pression of the pushbutton 124 first initiates operation of the magnetically sensitive contact-less light emission initiation circuit 121 as to. emit light from the photo lens light source 122. This is depicted in the curve shown inFIG. 13A (1) wherein the .solid line depicts l. the electric current pulse supplied by the magnetically i trates the intensity of the ensuing light'pulse produced sensitive light emission initiationcircuit 121 to the photo lamp light means 122, and the dotted line illusas .a result of the excitation of the photo lamp light I source 122. Continued sequential depression of the 1 down to its second dotted line position 125b to thereby face of a second magnetic initiation control circuit shown at 126 The magnetic initiation control circuit 126, in place of initiating operation of a photo lamp light source such as 122, instead initiates operation of a conversion circuit of conventional construction. The conversion circuitmay be comprised by a push-pull transistor power converter circuit of known construc- Y posure element 127 because it operates as a combined shutter/aperture controls both the time of opening, as well as the extent ofexposure of the film plane 129 to a subject being photographed through the lens 128. For

a more detailed description of the electricallyconpushbutton 124 brings the permanent magnet 125 initiate operation of the. magnetic initiation and conversion circuit 126. This circuit thereafter. functions to produce an output electric current pulse having the wave shape shown in FIG. 13A (2) to provide appropriate excitation of the electrically controlled shutter/aperture exposure control element 127. From a comparison of the time relation of the current pulse shown in FIG. 13A(2) to that shown in curve (l), it will be seen that the timed exposure control of the electrically operable exposure control element'l27 coincides substantially with the light pulse a light source122.

FIG. 14 is a functional block' diagram of an even more complete electronic control system for a camera wherein the required time delays between operation of the several subsystems of the camera is achieved electronically. The controlsystem shown in FIG. 14 also is designed for use with an array of photo lamp means which may be selectively sequentially flashed. The control system shown in FIG. 14 employsa magnetically sensitive, contact-less light emission initiation circuit 121 whose operation is controlled by a permanent magproduced by the photo lamp net 125 through the medium of a pushbutton 124. The magnetically sensitive light emission initiation circuit 121 may be fabricated in accordance with the teachings of any of FIGS. 4-12, and operates to supply direct .current energy from an energy source 123 to a delay synchronizing circuit 131: The delay synchronizing cir- 129 is extremely high speed, or the lighting background, etc. produces a high intensity image, the control pulse supplied to theelectrically controlled exposure element 127 may be extremely short in duration such as depicted by the pulses 136a, 136b, etc., to.

' thereby obtain onlya very short time duration exposure cuit 131 may be fabricated in accordancewith an'ysof comprise any known transistor converter circuit, or a SCR, SUS, or other known DC to DC power converter of the film plane to the subject being photographed. Alternatively, if the film employed is relatively slow in speed, or the background, etc, produces only a very low level intensity image, the time duration of the control' pulse to the exposure element 127 may extend out to the point 136], etc. By this means, closed loop control over the extent of exposure of the film plane to the circuit susceptible of fabrication in accordance with insor 135 then controls tum-off of the IC converter 134 so as to provide a substantially closed loop control of the exposure time of the film plane 129. I

In operation, assuming that a camera employing the system of FIG. 14 has been properly conditioned for the taking of a picture,the operator then depresses the pushbutton 124. This results in moving the permanent magnet from the solid line position shown at 125 to the dotted line position at 125a and thereby initiatesoperaw' tion of the magnetically sensitive-light emission initiation control circuit-1'21 in the-manner previously de scribed'in connection with FIGS. 4-12 to supply energization current to the'delay synchronizingcircuit 131. Delay synchronizing circuit 131 then supplies a current pulse such as shown in solid form in FIG. 14A( 1) to the array control circuit 132 which contains selectively to flash or emit light from 'a desired one of an array of photo lamps comprising light source 133 as depicted by l the dotted line curve shown in FIG. 14A(l). Concurrently with this action, the delay synchronizing circuit subject being photographed is positively provided to assure acceptable quality image reproduction at the film plane 129. Because substantially all of the elements of the camera control system shown in FIG. 14 are electronic in nature, the entiresystem is susceptible "to. manufacture in integrated circuit form whereby it canbe employed in a hand-held camera. Thus, it can be produced and sold at relatively low cost while assuring relatively high quality image production.

FIG.15 is a schematic circuit diagram of still another different form of contact-less light emission initiation control circuit constructed in accordance with the invention and which employs a light emitting diode and light activated SCR to achieve contact-less light emission-initiation. The arrangementrshown in FIG. 5 employs a spring wound rotatable shutter plate 42 that automatically is rotated in a counterclockwise direction upon the pushbutton 47 being depressed to release the end of lever arm 46 from the stop upon the user'of the camera desiring to snap a picture, all in the. manner previously described with relation to FIG. 4 of the drawings. The arrangement'further includes a photo lamp means '17 that may comprise a single photo lamp, a. fla'shcube, a linear array of flashbulbs, or an array control circuit selectively controlling desired ones of an array of flash lamps, etc., as described previously. The photo lamp means "is designed to be inserted into, a

L pressure socketfitting so that it is self-cleaning insertion and removal of the photorlamp bulbs. The ter- 131 supplies a'delay energizing pulse to the electrically controlled shutter/aperture exposure element :127 to,

the current pulse. These different trailing edges depict the manner in which the time duration of the excitation current supplied to the electrically controlled exposure element 127 can be varied in accordance with the setting of the sensor 135 for different. film speeds employed at the film plane 129 or as determined by the intensity or level of light of the image beingphotographed. Thus, if the film employed atthe film plane v minals of the socket for the photo lamp means 17 are connected in series circuit relationship with a source of electric energy 15 that may comprise a battery, piezoelectric generator, etc. The source of electric energy 15 mayieven comprise an expendable paper battery such as that described by the Norelco Manufacturing Company in recent literature released by that company.

Theseries circuit comprises by 17 and 15 is con.- nected across a first circuit branch comprised by a light emitting diode 141 (referred to as a LEDlconnected in series circuit relationship with a limiting resistor 142. The light emitting diode'l4l may comprise any con- 4 ventional, commercially available light emittingdiode such as the gallium arsenide diode manufactured and sold by the Miniature Lamp Department of the General Electric Company, a visible light emitting diode of gal- .lium phosphide also manufactured and sold by the Miniature Lamp Department of the General Electric Company, and other such similar devices. Light emitted by v thelight emitting diode 141 is'intended to pass through an initiating opening 143 formed in the rotatable shutter member 142 upon the opening 143 becoming aligned with an opening 144 in a stop. Light transmitted from the light emitting diode141 through openings 143 and 144 will impinge upon the light sensitive surface of a light activated silicon control rectifierl45 re ferred to asa LASC R); v e

The .LASCR is a. conventional, commercially available device manufactured andsold by the Semiconduc-f tor Products Department of the General Electric Company and may befabricated in either discrete or inte grated .circuit form, and constitutes a second circuit branch connected inparallel with the circuit branch comprisedby LED 141 and limiting resistor 142. With the circuit arrangement thus comprised, the' photo.

lamp 17 serves as anon-off switchin the mann'er'of an electric fuse and requires that the bulb notbe placed in the terminal until such time that the camera isready for use. Thus, while the circuit is stored on a shelf, etc., between periods of use, the flashbulb should not be inserted in its receiving socketfwhen it is desired to take a picture, the photo lamp '17 is inserted in the receiving socket thereby conditioning thecircuit for the taking of a closed circuit is produced through thejcircuit branch including the LED 141*.This device is designed to draw a current of about-0.0lampere which is so small asnot to constitute a serious drain on the battery source '15 while the'user of the camera is otherwiseoccupied in aiming, etc., the camera..I -Iowe'ver' it necessary that the photo la'mpll be of the varietythat'includes a filaelectric fuse-so that a further drain on the battery does not occur until the new bulb .is placed in the light socket to thereby condition the system to take a new picture. This operation would be carried out by user of the camera along with pre-winding the rotatable shutter member 42 to condition it for the taking of a new picture.

. a picture. It will be noted, that when thusconditioned,

Should it be d esired, the contact-less light-emission control circuitshown at 15 could'be modified by replacing the light emitting diode 141 and limiting resis-- tor l 42jfwith an alpha particle source such as that shown in dotted outline form at 146., With the control thus modified, itis essential that the rotatable shutter member 42 or other shielding member be fabricated of a material which will shield the film at the film plane of the camera from alpha particle radiation from the source 146. In operation, the circuit will function in. substantially the same manner as describedearlier with relation to the LED version of FIG. 15, with the excep tion that the alpha particle source 146 now constitutes the source of initiating radiation that is directed onto a the radiant energy sensitive 'surfaceof the LASCR 145' m'ent for'supplying the required 0.01 ampere excitation current to LED 141.

When it is desired to take a'picture, the pushbutton I 47 is'released' thereby relea'sin'gthe spring driven rotat able shuttermember 42. As stated above, the LED 141 already has been energized so that it is emitting' light, l

which under priorconditions has beenblocked by the rotatable shutter plate 42. Upon the shutter plate rotatingthe two openings 143 and 144 into alignment, light from LED 141 passes through and impinges upon the light sensitive surface of the LASCR 145. This results in renderingLASCR l45. conductive and supplying plate 42 in the previously described manner. This will result in exposing the film planeof the camera'substantially concurrently jintime with the production of the light pulse by the photo lamp v 17.

upon the openings 143 and 144 coming intoialignment'.

Otherwise, the control circuit would function in substantially the samemanner as described in the preceding paragraphs.

'FIG. 1 s a schematic circuit diagram or an embodiment of theinvention which was built employing an Eastman Kodak Model 134 Instamatic camera modified to'include'a' contact-less light emission initiation control circuitshown in FIG. 16. The circuit elements employed in FIG.,16 are substantially identical to those described in connection with FIG. 5 of the" drawings,

and hence will not be againdescribed in detail. The only difference between the FIG. 16 circuit and that shown in FIG. 5 is the substitution of a light emitting diode 141 for themagnetically sensitive diode 41 used in FIG. 5, and the substitution of a light activated SCR 145 for the conventional gate controlled .SCR 18 and its associated gate control circuitry. Another distinction of importance is the inclusion of the additional initiating openingsl43 in the rotatable shutter member 42 and the additional opening 144 in a back plate (not shown) but depicted by dotted outline form in FIG. 16.

These additional apertures serve to time or synchronize the exposure of the LASCR to light emitted from The voltage vs. time characteristic curve to the right of FIG. 15 illustratesthe voltage characteristicsof an expendable paper battery of the type described by the Norelco Company. It will be noted that this type of battery must be activated by the user by squashing a suit- I able electrolyte fluid vial in advance of using the expendable paper battery as an energy source. Following the squashing of the electrolyte vial, voltage across the battery will rise substantially in the manner'shown by the characteristic curve shown in FIG. 15. Atsome point indicated by the dotted line, thereafter, the system of FIG. 15 may safely be employed by the user of the circuit to take reliable flash pictures,and he will be assured of an adequate energy source to operate the system in the manner described abovei It should be further noted that following the flashing of the photo lamp LED 141 and theLASCR 145 (not shown in FIG. 6 of thelight emitting'diode 141 as described previously in 1 connection with'FIG. '15 of the drawings. I

The particular trigger mechanism thatwas employed to'trigger the shutter plate isthe same as that shown in FIG 6 of the drawings and described-previously in connection with FIG. 5. The trigger mechanism of FIG. 6 when, used with the light activated system of. FIG. 16 is moditiedto remove the permanent magnet previously described and insert instead the two openings. l43 'and 144 to allow for timed passage of light between the the drawings).ln all other respects, the trigger mecha 17 it will become open-circuited in the manner of an nism was constructed and operates in substantially the same manner as described previously in connection with FIG. 6, and-is substantially the same as that em- -ployed in a Model 134 lnstamatic camera. e Briefly, however, it will be seen that upon placing the camera control system of FIGS. 16 and 6 in operation,

, depression of the pushbutton 47 will release the ampli-' fying arm 71 for movement counterclockwise from its dotted line position to its solid line position'shown in FIG. 6. Upon this occurrence, the amplifying arm 71 sweeps across the lever arm 67 causing the shutter plate 61 to rotate clockwise thereby opening or exposing the aperture opening 44. Prior to this occurrence, in the sequence of events, the additional opening 143 in the rotatable plate 69 will have swept across the additional opening 144 thereby-allowing light emitted from diode 141 to impinge upon the light sensitive surface of the LASCR 145. This renders LASCR 145 conductive and initiates light emission from a photo lamp (not shown) connected to the terminals 17a, 17b shown'in FIG. 16. This light emission is timed to occur substantially simultaneously with the maximum opening of the aperture 44 by the shutter plate 61 The extent (diameter) of the optical path provided through the aperture opening 44 is controlled by the exposure control 51 in accordance with the ambient light level as iswell-known inthe art. The time duration of the opening of the aperture 44 will of course be controlled by the time required for the return spring 65 to return the shutter plate 61 to its normal, quiescent position shown in solid line,in FIG. 6. It will be appreciated tingdiode 141 to thelightsensitive surface of the LASCR 145 at a particular point in the angular travel of shutter member 61' where it is desired to render the LASCR. 145 conductive. By thusmodifyng the arrangement of FIGS.'16 and 6, it nolonger becomes necessary to cut the openings 143 and 144 in the trigger mechanism shown in FIG. 6. This simplifies the manufacture of the assembly, as well as relaxes some of the requirements on the location of the LASCR 145 and LED 141. Additionally, because only the formation of a light reflecting surface 149 is required, no substantial mass, is

I added to the shutter mechanism 61 thereby enhancing its performance. Further, it might be noted that the provision of the low mass, light reflective shutter member light emission initiation shown in FIG. 6A, and similar arrangements described herein allows a designer of a camera shutter trigger mechanism to go todirect acting shutter arrangements in contrast to indirect acting shutter trigger mechanisms. This is due to the fact that the trigger mechanism will now no longer be required to actuate auxiliary electrical contacts or other similar tasks which impose a mechanical loading on the trigger mechanism. The result is to greatly simplify the task of 24 of non-use. To avoid this from happening, a capacitor 151 is inserted in thecircuit branch between the light emitting diode 141 and the limiting resistor 142. In this arrangement, the LASCR 145 again is connected through the photo lamp 17 in parallel with the circuit branch including the light emitting diode 141 across the, batterysource 15. Here again the photo lamp 17 will serve as an on-off fuse'for discontinuing conduction through the LASCR 145 after being flashed, and a new bulb must be inserted in the circuit by the user in order tocondition it for re-use.

Withthe circuit arrangement of FIG. 17, prewinding or cocking of the trigger mechanism of the camera will automatically open theswitch 16. However, due to the fact that the switch 16 previously was closed'on its fixed contact, the capacitor 151 will have been charged to the full voltageof the battery source 15. Assuming that there is a fresh flashbulb 17 in the circuit, then upon closure of switch 16 by the user of the camera, sufficient energy will bedischarged from the capacitor 151 through LED 141 to initiate light emission and selectively activate the light activated SCR 145. This recharacteristic of the LED 141. It can be seen that by appropriate design location of the exposure openings of the camera (not shown) relative to the energization of the LED 141 at a point such as shown by the dotted line, synchronized, contact-less light emission initiation can be obtained with the circuit of FIG. 17. Further, because the switching mechanism of the camera is of the type wherein the contacts 16remain closed after use, the inclusion of the capacitor 151 will prevent further 'current drain on the battery source 15 after it has once become charged to the voltage of the battery.

From the foregoing description, it will be appreciated that the present inventionprovides a family of new and improved'contact-less light 'emission initiation circuits for use incontrolling operation of photo lamps, flashbulbs, flash cubes, lamp arrays, etc., employed in lighting subjects to be photographed with a camera. The

' contact-less photo lamp light emission initiation circuits may be fabricated in micro-miniaturized integrated circuit form, are capable of reliable operation even with low voltage electric energy sources, such as expendable paper batteries, and the like, and may be 4 for camera control systems constructed in accordance with the invention, it is believed obvious that'other modifications and variations of the 'inventionare possithe designer of the trigger mechanism as well as to allow for improved performance of the mechanism.

FIG. 17 is a schematic circuit diagram of a different form of light activated, contact-less light emission initiation circuit for use with a camera control of the type having an on-off switch 16 that is-jnormally closed and maintained closed after the taking of a picture.- With such on-off control switch design, it can be seen that the circuit arrangement-of'FIGS. 15 and 16 would.

ble in the light of the above teachings. It is, therefore, to be understood that changes may be made in the particular embodiments of .the invention described which are in the full intended scope of the invention as deinitiate light emission from the same upon the establishment of a closed electric current path through the elecacross said electric supply terminal means, means coupling said control electrode of the semiconductor 1 synchronization.

switch means to the junction of said device and load resistor, and magnetic means to impress a magnetic field on said magnetically sensitive semiconductor device in synchronism with the opening of a camera shutter, said magnetically sensitive semiconductor device being provided with aplurality of individual magnetically sensitive areas, said magnetic means being adapted to impress said magnetic field on said magnetically sensitive areas in time sequence, and including means for selectively connecting any of said magnetically sensitive areas in series with said load resistor for achieving flash

Claims (1)

1. A contact-less photo lamp flashing circuit comprising electric supply terminal means for connection to a source of electric energy and to photo lamp means to initiate light emission from the same upon the establishment of a closed electric current path through the electric supply terminal means, the source of electric energy and the photo lamp means to be energized, semiconductor switch means connected in the current path intermediate the photo lamp means and source of electric energy for controlling the closure of the current path to the photo lamp means, said semiconductor switch means being provided with a control electrode for selectively rendering said semiconductor switch means conductive, a magnetically sensitive semiconductor device and a load resistor connected in series across said electric supply terminal means, means coupling said control electrode of the semiconductor switch means to the junction of said device and load resistor, and magnetic means to impress a Magnetic field on said magnetically sensitive semiconductor device in synchronism with the opening of a camera shutter, said magnetically sensitive semiconductor device being provided with a plurality of individual magnetically sensitive areas, said magnetic means being adapted to impress said magnetic field on said magnetically sensitive areas in time sequence, and including means for selectively connecting any of said magnetically sensitive areas in series with said load resistor for achieving flash synchronization.

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