CA1122455A

CA1122455A - Lens movement actuated reference and sequencing means for cameras having unidirectional automatic focusing

Info

Publication number: CA1122455A
Application number: CA318,864A
Authority: CA
Inventors: Edwin K. Shenk
Original assignee: Polaroid Corp
Current assignee: Polaroid Corp
Priority date: 1977-12-30
Filing date: 1978-12-29
Publication date: 1982-04-27
Also published as: ATA1279A; FR2413680B1; AU4306279A; AT377101B; GB2013353A; DE2856573A1; FR2413680A1; GB2013353B; AU525816B2; JPS54109837A; CH637222A5; IE782563L; IE48251B1

Abstract

ABSTRACT OF THE DISCLOSURE
A unidirectional focus control system for a variable focus lens moves said lens outside of its normal focusing range in order to establish a reliable reference point to which or from which said lens is moved for variable focus lens focusing. In addition, lens movement outside of its normal focusing range provides the means for actuating switch means whose actuation initiates or inhibits the initiation of an event or a series of events.

Description

584~
`` ~L~,'Z;~45i~

BACKGROU_ D OF THE INVENTION
1. Field of the Invention The present inven-tion relates to a control system for a variable focus lens in gene~al, and to such a control system for a variable focus lens in a photographic camera, in particular.

2. Description of the Prior Art Variable focus lenses and apparatus utilizing such lenses such as photographic cameras, telescopes and the like are well known and their operation are well understood in the prior art. A camera having a variable focus lens and having a focus control sys-tem coupled to said lens for auto-matically focusing image-containing light rays of a remote object at the film plane of said camera in response to a rangefinder derived signal representative of the actual distance between said camera and said remQte objectr are known in the prior art. A camera having such a focus control system that utilizes acoustical energy to determine the distance to an object remote from said camera is described in U.S. Paten-t No. 3,522,764 to BIBER et al.
A bidirectional focus control system, i.e., a focus control system that, once commanded to do SQ, can move the movable element of a variable focus lens in either of two directions from any initial position within the normal focusing range of said lens, for focusing purposes, is also known in the prior artO One example of such a system is described in the above-mentioned BIBER et al. patent.
Another type of focus control system for a variable focus lens is somethimes referred to as a unidirectional focus .,.
~

control system in that -the movable or focusing element of such a lens is always moved from the same or known reference point for focusing purposes. While such an element is movable in either of two axial directions, no lens focusing is performed as said element moves withi.n its focusing range towards sald reference point. A unidirectional focus control system of this type is signif:icantly less complex -than a bldirectional focus control system because it is unnecessary to continuously monitor lens element movement as said element is moved toward said known reference point. The cost savings a-ttendant a unidirectional focus control system over a bidirectional focus control system makes it attractive to the control system designer. An example of a unidirectional focus control system for a variable focus camera lens is described in U.S. Patent No. 3,713,371 to KURIHARA et al.

When utilizing a unidirectional focus control system for a variable focus lens, it is necessary to always return the movable element of such a lens to a known reference point as previously mentioned. As a practical matter, what this means is that an actuator must fairly rapidly drive said movable lens element into a fixed mechanical stop that functions as said known reference point, which often results in said movable element bouncing off and normally remaining at some fixed distance or at some offset from said fixed mechanical stop. The unidirectional focus control system will incorrectly assume that -the movable lens element is resting against said mechanical stop or is positioned at said known reference point and may misfocus the lens in proportion to said bounce di.stance or offset. Even if the movable element is positioned precisely at a known reference ~ Z4~5 point the mechanical coupling bet.ween said movable element and the actuator that is driving said element is normally fairly loose which will enable said actuator to move a finite distance before it moves said movable lens element, which may also resul-t in a misfocusing of said variable focus lens by said unidirectional focus control system because of said finite distance movement.
In a variable focus lens focus control system, it is sometimes desirable to be able to utilize lens movement as the triggering means to initiate a lens related function or series of functions. If such an event is to be initiated well within the focusing range of said variable Xocus lens, lens movement can often be readily utilized as said triggering or initiating means~ However, if -the event is to be initiated precisely at either end of -the variable focus lens focusing range, certain problems are encountered, especially if the event is to be both initiated and terminated at the same position. In such a situation, lens movement is required before an event is initiated at one end of the focusing range or the other. ~y definition then, the event cannot occur ; until the lens has moved, at least a finite distance away from its starting point, which necessarily causes an event initiation error that is proportional to said finite distance.
This error can be minimized, but it cannot be entirely ellmi-nated. Even when this error has been minimi~ed to what might be deemed an acceptible level, it i6 very difficult, if not impossible, to construct switch means that will open and close at precisely the same point in response to lens element move-ment, whether such movement be rotational or translational.
This diffe:rence between the opening and closing position of ~Z'~:~L55i the movable element oE a variable focus lens to open and close said switch means may introduce additional control system or event errors that might make the use of lens movement to initiate and/or terrninate events at the focusing range end points of a variabl~ Eocus lens, impractical.
In accordance with a preferred embodiment o the present invention, a unidirectional focus control system for a variable focus lens is provided that moves said lens outside of its normal focusing range in order to provide an accurately defined reference point from which or to which said lens is always moved for variable focus lens focusing.
In addition, lens movement outside of its normal focusing range is utilized to actuate switch means or lens movement sensing means whose actuation or state is utili~ed to control functions that are related to or supportive of lens focusing and/or to control other devices that might be combined with said variable focus lens.
According to a broad aspect of the invention, there is provided a focus control system for use in a camera having an image plane and comprising: means ~or selectively coupling said camera to a source of electrical energy; a lens mounted for displacement over a given operational range wherein it serves to focus images of subjects positioned within a normal range of distances at said image planeJ and also for displacement outside of its operational range into another range wherein it does not focus images at said image plane, said lens being normally located within its other range when said camera is inoperative; means for producing a signal indicative of the position of a subject within said normal distance range; and drive means responsive to said signal for effecting the movement of said lens from its other range into its operational range to focus an image of the subject at said image plane.
The invention will now be described in greater detail with reference to the accompanying drawings, in which:
Fig. 1 is a schematic diagram of an automatic focus control .

system for a variable focus lerls that is constructcd in accordance with a preferred embodiment of the presen-t inventio~
Fig. 2 is a front elevational view of the lens mounted motor driven cncoder gear, lens movement actuated switch, and the lens position sensing pick-off module of thc present invention.
Fig. 3 is a schematic diagram showi.ng the full range of movement of the variable focus lenses controlled by the focus control systems of the present invention.

J ! -4a-:1 ~22~55 Fig. ~ is a schematic diagram of an automatic and manual focus control system of a preferred embodiment of the present invention that requires manual positioning of said control system f~om its manual mode to its automatic mode.
Fig. 5 is a schematic diagram of an automatic and manual focus control system of a preferred embodiment of the present invention that automatically returns said control system to its automatic mode whenever its manual mode is utilized.
Fig. 6 is a schematic diagram of the control system depicted in Fig. 4 incorporating a two stage switch; one stage primarily for lens focusing and the other stage primarily for contxolling a film exposure cycle.
Fig. 7 is a schematic diagram of the control system depicted in Fig. 5 incorporating a two stage switch; one stage primari y for lens focusing and the other stage primarily for controlling a film exposure cycle.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
Referring now -to the drawings and, specifically, 2~ to Fig. l, where a schematic diagram of an automatic focus control system for a variable focus lens incorporating a preferred em~odiment of the present invention is depicted.
A source of electrical power (not shown) is supplied to one terminal of spring force biased, manually actuated, single pole switch Sl and to one terminal oE lens movement actuclted sinyle pole switch Sp through terminal 12, to which said source of powex is connected. Either signal Sl or signal Sl will appear a-t the output of switch Sl when said switch S
is actua-ted. Signal Sl will appear at the output of switch S
when switch Sl is closed and signal Sl will appear at the output of switch Sl when switch Sl is opened. Signal Sp wi.l appear at the output of switch S ~hen said switch Sp is closed. Rangefinder 14 determines the distance to object 16 for variable focus lens 18 focusing purposes. Rangefinder 14 may be optical, but is preferably of the acoustical type similar to that shown in United States Patent No. 3,522,764 to BIBER et al~
Rangefinder 14 is actuated by manually closing spring force biased switch Sl, said switch Sl being normally spring force biased to the open position. ~ten switch Sl is closed, transmitter 20 and clock oscillator 22 are simulta-neously activated. Transmitter 20 transmi~s an acoustical burst of energy toward object 16 and clock oscillator 2Z starts generating a series of equally spaced time related pulses.
Counter 24 counts the pulses being generated by clock oscillator 22 and transmits these pulses to decoder 26 and to counter 28. Upon receipt of an acoustical echo reflected from object 16, initially transmitted by transmitter 20, receiver 30 generates and transmits a signal to clock oscilla-tor 22 through latching OR gate 32 to stop clock oscillator 22 at a point where the number of pulses generated by said clock ascillator 22 are representative of the total time taken for said acoustical burst of energy to reach object 16 from rangefinder 14 and to return to said rangefinder 14. 'l~le speed o sound in air is well known and thereore if one knows the time it takes to transmit an acousticcLl burst of energy to and receive a reflection or an echo of that acoustical burst of energy rom a remote object, the distance to ~hat remote object can be readily determined. If clock oscillator ~ZZ4~55 22 generates 124 pulses before receiver 30 receives a reflec-tion of the acoustical energy transmitted by transmitter 20, decoder 26 will send a signal to clock oscillator 22 through latching OR gate 32 to stop clock oscillator 22 at 124 pulses.
S Decoder 26 limits clock oscilla-tor 22 to :L24 pulses because 124 pulses represents the infinity focus position of variable focus lens 18 and any object located beyond that position, which would otherwise result in clock oscillator 22 generating more than 124 pulses, ls assumed to be in focus.

As previously mentioned, gate 32 is a latching OR

gate which means that if a normal input to gate 32 is removed, the output from said gate 32 that is caused by said input will be maintained. This is so because once there is an output at a logic gate of this type, said output is fed back into the input of the same ~ate which causes said gate to be maintained in its conducting state. The output from gate 32 is removed only when said gate is reset by a pulse that is generated by one-shot multivibrator 34, said multivibrator generating said pulse when switch Sl is ac-tuated to its closed positlon.
In variable focus lens control system 10, focusing, i.e., movement of variab]e focus lens 18 by focus control portion 35 of said control system 10 is not initiated un-til the distance to an object such as object 16 has first been deter-mined. When an ou-tput appears at latchiny OR gate 32, the dis-tance to object 16 has been determined so far as focus control portion 35 of sald control system 10 is concernecl When thc~ output from latchlng OR gate 32 is combin~d with signal Sl ~rom closed switch Sl, AND gate 36 will conduct and trans-mit a drive forward signal to drive mo-tor 38 until focusing is complete which will move lens mount 39 and the movable .

element of variable focus lens 18 in the forward direction for lens focusing purposes. Encoder wheel 40 is mounted in a fixed relation with respect ko lens mount 39 and therefore encoder wheel 40 movement is representative of the position of lens mount 39 and oE the movable element of variable focus lens 18 which is mounted on said lens mount 39.
Pick-off module 42 includes a light emitting diode and a light sensitive transistor that is sensitive to the light output from said light emitting diode. As encoder wheel 40 rotates in response to lens mount 39 movement, slots in said encoder wheel 40 alternately block and unblock the light being transmitted between the light emitting diode and the light sensitive transistor in pick-off module 42 thereby genera~ing pulses that are representative of the position of lens mount 39 and of the movable element of variable focus lens 18. The pulses from pick-off module 42 are transmitted to and are counted by counter 28. When the number of pulses generated by clock oscillator 22 and pick-off module ~2 reach a combined total of 128 in coun-ter 28, decoder 44 yenerates output signal 46 indicating that the focusing of variable focus lens 18 is complete. Focus complete signal 46 causes one-shot rnultivibrator 48 to momentarily energize pawl relay 50 which causes pawl 52 to engage encoder wheel 40 thereby stopping the motion oE saicl encoder wheel ~0 and the movable el.ement o.E va.rlable eocus lens 18. Simul-tane,ously therew:ith, focusiny complete s:igna:L ~6 :is inverted by inverter 5~ and the laclc of an output :Erom inverter 5~ causes A~D gate 36 to open, thereby shu-tting off the drive :Eorward signal to drive motor 38 which removes the lens focusing driving force from lens mount 39. At this point, an image of object 16 has been , focused at an image plane for viewing through variable focus lens 18.
When the viewing of object 16 through variable focus lens 18 is comple-te, swi-tch Sl is open~d. When switch Sl is opened, signal Sl is generated at -the output o~ switch Sl and is transmitted to AND ga-te 56. When signal Sl and signal Sp are combined, AND ~a-te 56 conducts and a reverse drive signal is sent to drive motor 38, causing said drive motor 38 to drive lens mount 39 and the movable element of variable focus lens 18 in a direction opposite to that in which it was driven in order to focus variable focus lens 18 on object 16. As previously discussed, signal Sp is generated when switch S
is actuated to the closed position. Switch Sp is coupled to lens mount 39 and it is -the movement of lens mount 39 that actuates switch Sp. When lens mount 39 moves from its initial position toward its in-focus position, switch Sp is actuated to its closed position thereby generating signal Sp at lts output. Conversely, when switch Sp is actuated to its open position by lens mount 16 movement from its in focus position to its initial position, signal Sp disappears from its output.
The actuation of switch Sp in relationship to the position of lens mount 39 constitu-tes a basic part of the present invention and the actuation of this switch with respect to said lens ~nount 39 wil:l be discussed in greater detail with respect to Figs. 2 and 3.
With continued reEerence to Fiy. 1 it should be noted that in ac1dition to -the control or logic signals provided by switches Sl and Sp, these switches can also be utilized to disconnect any and all loads from the power source that is supplying power to tèrminal 12. The outputs of switches S

and Sp are also fed to OR yate 58 and then to as many electri-cal loads as desired. When switch Sl is eventua]ly opened, power continues to be supplied to variabIe focus ~lens control system 10 and any other selected loads through lens movement actuated switch Sp. However, when switch S lS returned to its initial position, switch Sp opens and all electrical loads that are receiving power through switch Sp and terminal 12 are disconnected.
'rurning now -to Fig. 2, which is a front elevational view depicting the lens movement actuator and the lens position sensing means of the present invention. Movable~lens element 59 is mounted on lens mount 39 for rotational movement about and along axis 60. Encoder wheel 40 is mounted on lens mount 39 and the periphery of encoder wheel 40 is in the form of a gear that is coupled to drive motor 38 through drive motor pinion gear 62 and idler gear 64.
Variable focus lens 18 (Fiy. l) is mounted on support housing (not shown) in a manner that is similar to the way in which the variable focus lens depicted in U.S. Patent No.

3,914,777 to SLAVITTER is mounted on its support hous:ing.
Lens mount 39 has a threaded portion of circular cross section, that moves into and out of a ma-ting threaded member that houses the fixed elements of said variab:le focus lens 18 as in sa:id SLAVITTER patent, as saicl lens mount 39 together with movab:Le element 59:is rotated about rotational axis 60. 'rhe relationshlp between drive motor 38 and movable element 59 of variable focus lens 18 is such that drive motor 38 provides the driving force that moves movable element 59 about and along said axis 60.

. . ..

S~

Encoder wheel 40 includes a plurality of slots 66 extending through said encoder wheel 40, said slots being positioned at the same fixed radial distance from axis 60, said slots being equally spaced along said fixed radial distance. When the -threaded portion of lens mount 39 of movable lens element S9 is rotated and thereby threaded into the housing that supports the fixed lens elements of variable focus lens 18, a known relati.onship mus-t be established between the rotatianal position of slots 66 about axis 60 and the axial position of movable lens element 59 of variable focus lens 18 along said axis 60. Once this relationship has been established, the focal position of variable focus lens 18 can be determined by counting the number of pulses generated by pick-off module 42 as slots 66 are rotationally moved through pick-off module 42 by drive motor 38. The specific details of how slots 66 cooperate with pick-off module 42 to generate a series of pulses was described above with reference to Fig. 1.
Encoder wheel 40 also includes cam portion 68 pro-jecting from the front face thereof. As encoder wheel 40 is driven in a clockwise direction by manual means or by drive motor 38, cam portion 68 of encoder wheel 40 eventually enyacJes switch Sp and actuates said switch Sp to its open position. The position of encoder wheel 40 where switch Sp is in its open position is herein defined as the park position of variable focus lens 18 (F'iy. 1). The operation of cont,rol system 10 (Fig. 1) is laryely dependent upon the :rotati.onal and axial position of movable element 59 of variable :eOcus lens 18 for the actuation of switch Sp and the generation of pulse by pick-off module 42. Therefore, at this point it would be useful to refer to Fic3. 3 in order to fully appreciate . .

the full range o movement of said movable element 59 and how said lens element movement relates to the operation o said control sys-tem 10.
In Fig. 3, variable focus lens 18 is depicted as a single lens element that is movable along object distance axis 70 for focusing purposes. Any object located between position Ml and col on ob~ec-t distance axis 70 is focusable by variable fbcus lens 18 at image plane 72. Oblects located at position Ml on object dis-tance axis 70 will be focused at image plane 72 when variable focus lens 18 is positioned at position ~. Therefore, the distance -to an object located at Ml represents the minimum focusing distance of said variable focus lens 18. Objects positioned at col on object distance axis 70 will have an image focused at image plane 72 by variable focus lens 18 when said variable focus lens 18 is positioned at oo. Objects appearing to the left of position Ml on object distance axis 70 cannot be sharply focused at image plane 72 by variable focus lens 18 and therefore objects appearing to the left of said position Ml will be considered as being in the out-of-focus reyions of variable focus lens 18. Objects appearing between positlon Ml and l on object distance axis 70 are withirl the norrnal. Eocus:ing reyion of said variable focus lens 18.
In addit.ion to the movement of variable :Eocus lens 18 within its normal focusing range, variable :Eocus lens :l8 is also movab:Le outside of its normal focusing range between its oo position,and position P which represents the park position of variahle focus lens 18 or the position at which switch Sp (Fig- 2) is in its open posi-tion. In this, the pre~erred embodiment, the P or park position is located between imaye plane 72 and the oo position of variable focus lens 18. However, this particular location for the park position of variable focus lens 18 is merely a design choice and could very well have been located between the M position of variable focus lens 18 and minimum focus position Ml on object distance axis 70.
Having described the full xange of movement of variable focus lens 18, the remaining s-tructural fea-tures affecting -the operation of control system 10 that are depicted in Fig. 2 will now be described. In Fig. 2, variable focus lens 18 is shown in its park position or in that position where switch Sp is in its open position. Switch S was actuated to its open position by the rotational engagement of cam portion 68 of encoder wheel 40 wi-th said switch Sp.
When commanded to do so by control system 10 (Fiy. 1), drive motor 38 will drive encoder wheel 40 in a counterclockwise ~, direction which will event~lally bring slots 66 into cooperative engagement with pick-off module 42 causing pulses to be generated by said pick-off module 42 in a manner -that was previously discussed. Any movement of encoder whee:L ~0 prior to the time slot 66A influences pick-ofE module 42 is herein referred to a.s lens park recJ:i.c)n movement or movement in the park regi.on oE var:iab:Le focus lens 18. :tf rangeeinder 14 (I~'ig. 1) has cleterlltirled that the distance -to an object to be viewed through variable t-ocus lens 18 is at inEinity, encoder wheel 40 will be moved by drive motor 38 until encoder wheel slots 64a, 64b, 64c and 64d have caused pick-off module 42 to generate four pulses for transmission to counter 28 (Fig. 1). With rangefirlder 14 having caused 124 pulses to be generated and transmitted -to counter 28 (Fig.1) -these additional four pulses generated by said encoder wheel 40and pick-off module 42 will add four addltional pulses to said counter 28 for a total of 128 counts. Once 128 pulses have been counted by counter 28, lens focusing movement is terminated by control system 10 (Fig.1) as previously discussed. Movement of variable focus lens 18 from the point where slot 66A oE encoder wheel 40 first influences pick-off module 42 to the point where slot 66d o~ encoder wheel 40 has completed its influence on pick off module 42 is herein defined as lens initializing movement because it is the minimum amount of lens movement that must occur before the automatic focus control system can correctly focus variable focus lens lg on any object and it is the minimum amount of movement required before variable focus lens 18 reaches one end of its focusing range which, in this the preferred embodiment, is the infinity position of said variable focus lens 18. If any of slots 66A, 66B, 66C or 66D were unable to cooperate with pick-off module 42 for pulse generating purposes, because of the position of said encoder wheel 40 at the time automatic focusing was initiated, a misfocuslng would be caused by the automatic focus control system that would be proportional to the number of such slots that were so positioned.
If less than 124 pulses hadbeen transmi-tted to counter 28 by range-~inder 14,encoder wheel 40would continue to be driven until the number of pulses generated by said rangefinder 14 and the number of pulses generated byencoder wheel40 and pick-of module 42 totaled 128 inorder to properly focus var.iable focus lens18 to the correct subject-in-focus positlon as determined by said rangefinder 14.
With reference to F'igs 1 and 2,varlable ~ocus lens 18 is returned to its park position,or Sp open position, by releasing spring force biased switch Sl (Fig.l)as previously discussed when viewing of an object through said variable focus lens is complete.
With variable focus lens 18 being in its normal ~ocusing range, Sp -14~
.

2~55 is closed ancl signal S is present atlts output. By openiny switch Sl and generating signal Sl,signals Sl and Sp sa-tisfy AND gate 56 which renders said AND gate 56 conductive. The output of AND gate 56 is transmitted to drive mo-tor 38 causing said drive motor 38 to drive encoder wheel 40 and variable focus lens 18 in a reverse direction towards -the park position or the S open position of said variable focus lens 18 as previously discussed. When cam portion 68 of encoder wheel ~0 engages s~itch Sp and actuates sald switch to its open position, power is removed from drive motor 38 before lens mount 39 is driven into mechanical stop 74 (Fig. 2). Movement of encoder wheel 40 after power has been removed from drive motor 38 is entirely dependent on the inertial forces supplied by drive motor 38, movable lens element 59 and the means coupling said drive motor to said lens element 59. The point at which switch S is actuated by cam portion 68 of encoder wheel 40 is not critical so long as at least two conditions are met. One condition is that when encoder wheel 40 comes to rest and switch Sp has been actuated to its open position, slot 66a or an equivalent first slot in encoder wheel 40 must be positioned between pick-off module 42 and the oo position of variable focus lens 18. Another condition that must be met, which is very much related to the first described condition, is that whe~
said switch Sp is actuated to its open position causing drive motor 38 to become deenerg.ized, there must be enouyh .i.nertia as~ociated wLth said drive motor 38, movAble lens element 5 and the means coupliny said dri.ve moto:r 33 to said movable lens element 59 to drive variable focus lens 18 into its parlc region to the point where slot 66a of encoder wheel 40 is positioned between pick-off module 42 and the o~ position of said variable focus lens 18. If slots 66a, 66b, 66c and 66d are not positioned between pick-off module 42 and the .

~2~S~

ininity position of variable ~ocus lens 18 when switch S is in its said open position, a misfocusing error will be created that will be proportional to the number of these slots that are not so positioned as previously discussed. In this the preferred embodimen~, switch Sp is actua~ed ~o its open position before variable focus lens 18 reaches its lens park region as defined in Figure 2. Also, when switch Sp is in its open position, lens mount 39 may or may not be in contact Wit}l mechanical stop 74.
Additional conditions may be placed on control system 10 requiring that lens mount 39 be in contact with mechanical stop 74 when switch Sp is open or that switch Sp be opened immediately after slot 66a of encoder ~heel 40 is moved between pick-off module 42 and the infinity position of variable focus lens 18 but, such conditions are not necessary for the operation of control system 10 as described herein.
Control system 10 depicted in ~igure 1 has been described as a control system for focusing a variable focus lens in general. However, focus complete signal 46 transmitted by decoder 44 could be utili~ed to trigger an electrically actu-ated shutter mechanism in a photographic camera or to initiate such a shutter mechanism and a film processing cycle in a self-processing film camera such as that marketed by the Polaroid Corporation under the registered trademark SX-70.

, ' .

Z~55 In Figure 4, focus control system 76 utilizing variable focus lens 77 movement outside of its normal focusing range in accordance with a preferred embodiment of the present invention, is depicted. In control system 76, a source of electrical power ~not shown) is supplied to one terminal of manually actuated, spring force biased, single pole switch S
and to one terminal of lens movement actuated single pole switch S through terminal 78, to which said source of power is connected. Either signal Sl or signal Sl will appear at the output of switch Sl when said switch Sl is actuated.
Signal Sl will appear at the output of switch Sl when switch Sl is closed and signal Sl will appear at the output o:switch Sl when said switch Sl is opened. Similarly, either signals Sp or Sp will appear at the output of switch Sp when said switch Sp is actuated. Signal Sp will appear at the output of switch Sp when switch Sp is closed and signal S ~ill appear at the output of switch Sp when said switch Sp is opened.
When switch Sl is closed for picture taking purposes thereby generating signal Sl, AND gate 80 is rendered conduc-tive if lens movement actuated switch S is open or if lens 77 is in its park position as previously discussed. If said switch S
is open, signal Sp will appear at AND gate 80 rendering said AMD gate 80 conductive when said signal S is combined with si.gnal Sl. When AND gate 80 is rendered conductive, range-finding means 82 is activated so that it can determine the 2~55 distance to a subject to be photographed, said rangefinding means 82 functionlng in a manner similar to that of range-finder 14 in Fig. 1. The output from AND gate 80 also renders latching OR gate 84 conductive. Latching OR gate 84 will remain conductive even if the input from AND gate 80 is removed, for the reasons discussed above, said OR gate 84 being rendered nonconduc~ive only when swi~ch Sl causes mul-ti-vibrator 86 to generate a single reset pulse when said switch Sl is actuated to its closed position. The output of latching OR gate 84 is fed to AND gate 88, said AND gate 88 being held nonconductive until focusing means 90 has caused the position-ing of variable focus lens 77 to the correct subject-in-focus position.

After the distance to a subject to be photographed has been determined by rangefinding means 8~, a range complete signal is sent to latching OR gate 92 and the output of latching OR gate 92 is transmitted to focus control means 90 to initiate variable focus lens 77 focusing. Latching OR gate 92 maintains a focus initiate signal to focusing means 90 after focusing movement of said variable focus lens 77 has caused the actuation of switch Sp to its closed position rendering AND gate 80 nonconductive and deactivating range-finding means 82 together with its focus initiating output.

Focus control means 90 functions in a manner similar to focus control 35 described above in some detail and depicted in Fig. 1. Focus control means 90 sends drive forward signal 9-to drive motor 96 commanding said drive motor 96 to drive lens mount 98 together with variable focus lens 77 to the correct subject-in-focus position, said in-focus position to be sensed by lens position sensing means similar to that lLS~i in said focus control system 35 (Fig. 1). Once focusing is complete, focus complete signal 100 renders AND cJate 88 conductive and -the outpu-t from said AND gate 88 renders OR
gate 102 conductive. ~he output from OR gate 102 actuates a shutter mechanism which exposes and subsequently initiates the processing of an instan-t developing film such as that utilized in the self-processing film camera mentioned above.
In a camera where instant developing film is not utilized, the output from O~ gate 102 would merely trigger a conventional, electrically actuated shutter mechanism. Once processing is complete or, in the case of a nonself-processing film camera, once the shutter mechanism has been fully actuated, shutter actuation or film processing complete signal 103 is sent to AND gate 104. If switch Sl has been actuated to its open position by a camera operator, signal Sl will be generated at its output and AND gate 106 will be rendered conductive because latching OR gate 84 is still in its conductive state as previously discussed, and the output ~rom said OR gate 84 is present at the input of said AND gate 106 together with signal Sl. AND gate 104 will be rendered conductive upon receipt of cornpletion signal 103 because AND gate 106 has been rendered conductive by the actuation of switch Sl to its open position and signal S is already present at the input o~ said AND gate 10~ because switch S was actuated to its closed posi.tion wh~n variable focu.s Lens 77 moved toward i~s normal Eocu~incJ rancJe. When ~ND cJa-te 10~ ls rendered conductive, a reverse drive sicJnal is sent to drive mo-tor 96 which, in turn, cause~s said drive motor to drive lens mount 98 toward its initial or park position to the point where switch S has been actuated to its open position by said lens mount ~8 movement in a manner similar to that in control system 10 described above and depicted in Figs. 1 and 2. When switch Sp is actuated to its open position, signal S will disappear from its output and gate 10~ will be rendered non-conductive, thereby shutting off the :reverse drive signal to drive motor 96. At this point, variable focus lens 77 is in its park position or in the posi-tion at which switch S is open.
If switch Sp had been in the closed position instead of in the open position when switch Sl was initially closed, AND gate 108 rather than AND gate 80 would have been rendered conductive. Switch S would be in its closed position if variable focus lens 77 had heen manually focused by a camera operator. With switches Sl and Sp both closed, siynals S
and Sp appear at the input of said ~ate 108. There is an output from inverter 110 because there is no ou-tput from latching OR gate 84 due to the lack of an output from AND
gate 80,which would satisfy said AND gate 108. An output from AND gate ~08 renders latching OR gate 112 conductive, sai.d OR gate 112 remaining in its conductive state until reset as previously discussed. An output from latching OR
gate 112 renders OR gate 102 conducti.ve which, in turn, initiates a film exposure and processing cycle in the case of a self-processing film camera or merely actuates an elec-trically actuated shut-ter mechanism .in the case of a nonself-processlrlcJ ei.lm came:ra.
Upon completion Oe film exposure, o:r of film exposure and processlng, which~ver the case might be, variable :eOcus lens 77 :is not dr.iven back to the pOillt where switch Sp opens o~ to the park pos~ ion oE said variable focus lens 77 ~Z~5~

as previously defined, because there will be no input from AND gate 106 to render said ~ND gate 10~ conduetive. AND
gate 106 remains in i-ts noneonductive state because of -the lack of an output from latching OR gate 8~.
With continued referenee to FicJ. 4, it should be noted that in addi-tion to the eontrol or logie signals provided by switehes Sl and Sp, these switches ean also be utilized to disconnect any and all loads from ~he power souree that is supplying power to terminal 78. The outputs of switehs Sl and Sp are also fed to OR gate 114 and then to as many eleetrieal loads as desired. When switch Sl is eventually opened, power continues to be supplied to variable foeuS len5 eontrol system 76 and any other selected loads throughlens movement actuated switeh S . However, when lens 77 is returned to its park position, switeh Sp is openecl and all eleetrical loads that are reeeiving power through switeh S and terminal 78 are diseonneeted.
In control system 76, variable foeus lens 77 is automatieally returned to its initial position or to the position where switeh Sp is opened only if said switeh Sp is open when switeh Sl was manually actuated -to its elosed position. Under these eonditions, eontrol system 76 ean be viewed as being in its au-tomatie mode. However, if Sp has heen elosed by the manual movement of variahle focus lens 77 into its normal foeusi.ng range in orc1er to manually ~oeug said lens on a subjeet to be photographed,thc-~ actuatlon Oe sw:iteh S
to its elosed position under these condit:ions will result in vari.able Eoeus lens77rertlainincJclt-the position to which it was previously manually focused, after a Eiltn exposure cycle is complete. ~t may be desirable to always return avariable Eoeus .. . . .

~ 5~

lens to its automatic position or to the S open position after a pic-ture is taken so that the focus control system would always be in a mode that would cause said focus control system to automatically focus a variable focus lens ~
on a subject to be photographed whene~er switch Sl is actuated to its closed position unless said variable focus lens had been manually positioned within its normal focusing range some time after switch Sl is actuated to its open position.
Such a system is depicted in the schematic diagram of Fig. 5.
]0 In Fig. 5, focus control system 116 utilizing variable focus lens 118 movement outside of i-ts normal focusing range in accordance with a preferred embodiment of the present invention, is depicted. In control system 116, a source of electrical power (not shown) is supplied to one terminal of manually actuated, spring force biased, single pole switch Sl and to one terminal of lens movement actuated sinyle pole switch Sp through terminal 120, to which said source of power is connected. Either signal S
or signal Sl will appear at the output of switch Sl when said switch Sl is actuated. Signal Sl will appear at the output of switch Sl when switch Sl is closed and signal S
will appear at the output of switch Sl when said switch Sl is opened.Sirnilarly, either signals S or Sp will appear at the output of switch Sp when said switch Sp is actuated.
Signal Sp wil] appear at the output of switch Sp when switch Sp is closed and 5iynal Sp will appear at the output o~ switch Sp when said switch Sp is opened.
When switch Sl is clos~d for picture taking purposes thereb~ generating signal Sl at its output, ~MD gate 12~ is . . . . . .

~Z~55 rendered conductive if lens movemen-t actuated switch Sp is open or if lens 118 is in its park position as previGusly discussed. If said switch S is open, signal Sp will appear at AND ga-te 122 ren~ering said AND gate 122 conductive when S said signal Sp is combined with signal Sl. When AN~ gate 122 is rendered conductive, rangefinding means 124 is activated so that it can determine the distance to a subject to be photo-graphed, said rangefinding means 12~ functioning in a manner similar to that of ranyefinder 14 in Fig. 1. The output from AND gate 122 also renders latching OR gate 126 conductive.~
Latching OR gate 126 will remain conductive even if the input from AND gate 122 is removed, for reasons discussed above, sald OR gate 126 being rendered nonconductive only when switch Sl causes multivibrator 123 to generate a single reset pulse when said switch Sl is actuated to its closed position. The output of latching OR gate 126 is sent to AND gate 130, said AND gate 130 being held nonconductive until focusing means 132 has caused the positioning of variable focus lens 118 to the correct subject-in-focus position. After the distance to a subject to be photographed has been determined by rangefinding means 124, a range complete signal is sent to latching OR gate 134 and the output of latching OR gate 134 is transmitted to focus control means 132 to initiate variable Eocus lens 118 focu~iny. ~tching OR gate 134 maintains a focus initiate signal to focusing means 132 after Eocusing movement of said variable focus lens 118 has caused the actuation of switch Sp to its closed position, the effect of which i.s to render AN~
gate 122 nonconductive and -to deactivate range~inding means 124 together with its focus initiating output to focus con-trol means 132.

~ s Focus control means 132 functions in a manner similar -to focus control 35 described in some detail above and depicted in Fig. 1. Focus control means I32 sends drive forward signal 136 to drive motor 138 commanding said drive motor 138 to drive lens mount 140 together with variable focus lens 118 to the correct subject-in-focus position, said in-focus position to be sensed by lens position sensing means similar to that in focus control system 35 (Fig. 1). Once focusing is complete, focus complete signal 142 renders AND
gate 130 conductive and the outpu-t from said AND gate 130 renders OR gate 144 conductive. The output from OR gate 144 actuates a shutter mechanism which exposes and subsequently initiates the processing of an instant developing film such as that utilized in the above-mentioned self processing film camera. In a camera where instant film is not utilized, the output from OR gate 144 would merely trigger a conventional, electrically ac-tuated shutter mechanism. Once processing is complete or, in the case of a nonself-processing film camera, once the shutter mechanism has been fully actuated, shutter actuation or film processing complete signal 146 is sent to AND gate 148. If switch Sl has been actuated to its open position by a camera operator, signal Sl will be generated at its output and AND gate 150 will be rendered conductive because latching OR gate 126 is still in its conductive state, and the output from said OR gate 126 is present at the input Gf said AND gate 150. AND gate 148 will be rendered conductive upon recelpt of completion signal 146 because AND gate 150 has heen rendered conductlve by the actuation of switch Sl to its open position and the output of said AND gate 150 is con.nected to the input of AND gate 148 through OR gate 152. Signal Sp ss is already present at the input of said AND gate 148 because switch Sp was actuated -to its closed position when variable focus lens 118 was moved toward its normal focusing range.
~hen AND gate 148 is rendered conauctive, a reverse drive signal is sen-t to drive motor 138 which, in turn, causes said drive motor to drive lens mount 140 ~owarcl its park position to the point where switch S has been actuated to its open posi-tion by said lens mount 140 movement. When switch Sp is actuated to its open position, signal Sp will disappear from its output and AND gate 1~8 wiIl be rendered nonconductive, thereby shutting off the reverse drive signal to drive motor 138. At this point, variable focus lens 118 is in its park position or in the position at which switch Sp is open.
If switch Sp had been in its closed rather than in its open position when swi-tch Sl was inltially closed, AND
gate 154 rather than AND gate 122 would have been rendered conductive. Switch S would be in said closed position if variable focus lens 118 had been manually focused by a camera operator. When switches Sl and Sp are both closed, signals S
and Sp appear at the input to said AND gate 154. There is an output from inverter 156 because there is no output from latching OR gate 126 due to the lac]c of an output from AND
gate 122~which would satisEy said AND gate 154. An output ~rom AND gate 154 renders latahing OR gate 158 conductive, said OR gate 158 remaining :in its conductive state until it is reset. An outpu-t from latching OR gate 158 renders OR
gate 144 conductive which, in turn, initiates a film exposure and processing cycle in -the case of a self-processing film camera or merely actuates a conventional, electrically actuated -2~-~z~

shutter mechanism in the case of a nonself-processing film camera. Upon completlon of film exposure, or of film exposure and processing, whichever the case migh-t be, shutter actuation ox film processing complete ~ignal 146 is sent to AND gate 148.
If switch Sl has been actuated to its open position by a camera operator, thereby generating signal Sl at its outpu-t, AND gate 160 will be rendered conductive because latching OR gate 158 is still in its conductive state, and the output from OR gate 158 and said signal Sl is present at the lnput of said AND
gate 160. AND gate 148 will be rendered conductive upon receipt of completion signal 146 because AND gate 160 was rendered conductive by the actuation of switch Sl to its open position and the output of said AND gate 160 ls present at the input of AND gate 148 through OR gate 152. Signal Sp is already present at the input of said AND gate 148 because switch Sp wàs actuated to its closed position when variable focus lens 118 was moved toward its normal focusing range.
When AND gate 148 is rendered conductive, a reverse drive signal is sent to drive motor 138 which, in turn, causes said drive motor to drive lens mount 140 toward its park position to the point where switch S is actuated to its open position hy said lens mount 140 movement. When switch S is eventually actuated to its open position, s.igrlal Sp will disappear from its output and AND gate 148 will be rendered nonconductive, thereby shutting o~f the reverse drive signal to drive motor 13~. At this point, variable focus lens 118 is in its park position or in the positlon at which switch Sp is open.
With continued reference to Fiy. 5, it should be noted that in addition to the control or logic signals provided by switches Sl and Sp, these switches can also be utilized to ~Z~5~3;

disconnect any and all loads from the power source that i5 supplying power to terminal 120. ~he outputs of switches S
and Sp are also fed to OR gate 162 and then to as many electrical loads as desired. When switch Sl is eventually opened, power continues to be supplied to control system 116 and to any other selected loads through lens movement actuated switch Sp. However, when variable focus lens 118 is returned to its park position, switch Sp is opened and all electrical loads that are receiving power through said switch Sp and terminal 120 are disconnected.
If control sys-tem 76 ~Fig. 4) focuses variable focus lens 77 on the subject to be photographed and a camera operator is able to view that subject as focusing is taking place, as in a single lens reflex camera, said camera operator ~ay want the~option of being able to prevent a picture from being taken after focusing is complete and prior to the initiation of a film exposure cycle. The focus control system depicted in Fig. 6 modifies the control system depicted in Fig. 4 such that switch Sl is replaced by two switches or as an alterna-tive, by a single switch having two stages. One switch or stage is primarily for the control of focusing and the other switch or staye is primarily for the control of picture taking.
In Fig. 6, focus control system 164 incorporating a two-stage switch, one stage primarily for lens focusing and the other stage primarily or controlliny a film exposure cycle, and utilizing variable focus lens 166 movement outside of its normal focusing range, in accordance with a preferred embodiment of the present invention, is depicted. In control system 164, a source of electrical power (not shown) is supplied to one terminal of manually actuated, spring force 5~i biased, single pole switch S1~, to one terminal o~ manually actuated, spring force biased, single pole switch SlT and to one terminal of lens movement actuated single pole switch Sp through terminal 168, to which said source of power is connected. Switches SlF and SlT are mechanically linked to one another to form a two stage switch such that switch 51F
must be closed before switch SlT can be closed. Either signal SlF or SlF will appear at the output of switch SlF when said switch SlF is actuated. Signal SlF will appear at the output of switch SlF when switch SlF is closed and signal SlF w111 appear at the output of switch Sl~ when said switch SlF is opened. Similarly, ~ither signal SlT or signal SlT will appear at the output of switch SlT when said switch SlT is actuated. Signal SlT will appear at the output of switch SlT
when said switch SlT is closed and signal Sl~ will appear at the output of switch SlT when said switch SlTisopened. Also, either signals Sp or Sp will appear at the output of switch Sp when said switch Sp is actuated. Signal 5p will appear at the output of switch Sp when switch Sp is closed and signal Sp will appear at the output of switch Sp when said switch Sp is opened.
Switch SlF primarily controls the automatic focusing of variable focus ].ens 166. When switch SlF is closed for focusing purposes thereby yenerating signal SlF, AND yate 170 is rendered conductive if lens movement actuated switch Sp is open or if lens 166 is in its park position as previously discussed. If said switch Sp is open, signal Sp will appear at the input of AND gate 170 rendering said AND gate 170 conductive when said signal Sp is combined with signal SlF.
When AND gate 170 is renclered conductive, rangef:inding means . .

172 is activated so that i~ can determine the distance to a subject to ~e photographed, said rangefinding means 172 functions in a manner similar to that of rangefinder 14 described above and depicted in Fig. I. The output from AND gate 170 also renders latching OR gate 17~ conductive.
Latching OR gate 174 will remain conductive even if the input from AND gate 170 is removed, said OR gate 174 being rendered nonconductive only when switch S1F causes multivibrator 176 to generate a single reset pulse when said switch SlF is actuated to its closed position. The output of latching OR
gate 174 is fed to the input of AND gate 178, saicl AND gate 178 being held in a nonconductive state until focusing means 180 has caused the positioning of variable focus lens 166 to the correct subject-in-focus position and switch S1T has been actuated to its closed position.
After the distance to a subject to be photographed has been determined by rangefinding means 172, a range complete signal lS sent to latching OR gate 182 and the output of latching OR gate 182 is transmitted to focus control means 180 to initiate variable focus lens 166 focusing. Latching OR
gate 182 maintains a focus initiate signal to focusing means 180 after focusing movement of variable focus lens 166 has caused the actuation of switch Sp to its closed position which renders AND gate 170 nonconductive and deactivates rangefindirlg means 172 together with its focus initiating O~ltpUt. Focus con-trol means 180 eunctions in a manner similar to focus control 35 (Fig. 1). Focus control means 180 sends drive forward signal ]8~ to drive motor 186 commanding said drive motor 186 to drive lens mount 188 toyether with variable Eocus lens 166 -to the correc-t subject-in-focus position, said ss in~focus position to be sensed by lens posltion sensing means similar to that in said focus control system 35 (Fig. 1).
Once focusing i5 complete, focus complete signal 190 is transmitted to AND gate 178. AND gate 178 will remain in a nonconductive state until switch SlT is actuated to its closed position for picture taking purposes. However, if a camera operator has determined that he does not want to initiate a film exposure cycle after focusing is complete, he would merely release or open switch SlF which would return variable focus lens 166 to its park position or to the siwtch Sp open position. Movement of variable focus lens 166 to its park or Sp open position under the5e conditions occurs because signals SlF and SlT are present at the input ~f AND gate 192 when switches SlF and SlT are in their open positions, and signal Sp is already present at the input of AND gate 192 because switch Sp was actuated to its closed position when variable focus lens 166 was moved toward its normal focusing range. In addition, there would be an output from inverter 193 because AND gate 194 would be in a nonconduct:ing state due to a lack of an exposure initia-te signal :Erom OR gate 195.
.The function of AND gate 194 is toprevent variable focuslens166 from being moved to its initial state before a film exposure cycle is complete. With signals Sp, SlF, S1T and anoutput frominverter 193 present at the input of AND gate 192, said AND gate 192 is rendered conductive and transmits a reverse drive signal to drive motor 186 through OR gate 196, and said dr.ive motor 186 drives lens mount 188 toward the lens 166 park position -to the point where switch Sp is actuated to its open position by said lens mount 188 movement in a manner similar to that in control system 10 described above and depicted in Figs. 1 and 2. When switch Sp is eventually actuated -to its open position, signal Sp will. d.isappear from its output and AND

..

gate 192 will be rendered nonconductive thereby shutting off the reverse drive signal to drive motor 186. At this point, variable focus lens 166 is in its park position or in the position at which switch Sp is open.
If, on the other hand, switch SlT is actuated to its closed position when focus complete signal 190 is present at the input of AND gate 178, signal S11, will appear at the output of switch SlT and AND gate 178 will be rendered con-ductive. The output from AND gate 178 causes latching OR
gate 198 to conduct and the output from latching OR gate 198 causes OR gate 195 to conduct. The output from OR gate 195 actuates a shutter mechanism which exposes and subsequently initiates the processing of an instant developing film such as that utilized in the self-processing film camera mentioned above. In a camera where instant film is not utilized, the output from OR gate 195 would merely trigger a conventional, electrically actuated shutter mechanism. Once processing is complete, or in the case of a nonself-processing film camera, once the shutter mechanism has been fully actuated, shutter actuation completion or film processing complete siynal 200 is sent to AND gate 202. If switch SlF has been released or actuated to its open position by a camera operator, signal SlF
will be generated at its output and AND gate 204 will be rendered coslductive because la-tching OR gate 174 is still in its conductive state and the output from said OR gate 174 is present at the input Oe sald AND gate 204 together with signal Sl~,. AND gate 202 will be rendered conductive upon receipt of completion signal 200 because ANV gate 204 has been rendered conductive by the actuation of switch SlF to its open position and signal Sp is already present at the input of said AND gate Z4~5~

202 because swltch Sp was actuated to its closed position when variable focus lens 166 was initially moved toward its normal focusing range. When AND gate 202 is rendered con-ductive, a revexse drive signal is s~nt to drive motor 186 through OR gate 196 which causes said motor to drive lens mount 188 toward its initial or park position until switch Sp is actuated to its open position. When switch S ls eventually actuated to its open position, signal S w111 disappear from its output and gate 202 will be rendered nonconductive thereby shutting off the reverse drive signal to drive motor 186. At this point, variable focus lens 166 is in its park position or in the position at which switch Sp is open.
If switch Sp had been in its closed rather than in its open position when switch SlF was initially closed, AND
gate 170 would not have been rendered conductive and focusing ~
by focus control means 180 would not have occurred. Switch Sp would be in said closed position if variable focus lens 166 had been manually focused by a camera operator. In order to initiate a picture taking sequence in this situation, switch SlT must be closed. With switches SlT and Sp both closed, signals SlT and Sp would appear at the input of gate 206.
There would be an output from inverter 208 because there would he no output from Latching OR gate 114 due to the lack of an output from AND ga-te 170. Rn output from RND gate 206 renders :Latching OR yate 210 conductive, said OR gate 210 remaining in its conductive state until it i5 reset as previously discussed.
An output from latching OR gate 210 renders OR gate 195 con-ductive which, in turn, initiates a film exposure and processing cycle in the case of a self-processing film camera or merely actuates a conventional, electrically actuated shutter mechanism in the case of a nonself-processing film camera.
Upon completion of film exposure or of film exposore and processing, each of which are herein referred to as a film 'j exposure cycle, whichever the case might be, completion signal 200 will render AND gate 194 conductive which will result in no output from inverter 193 and in variable focus Iens 166 r~maining at its subject-in-focus position.
With continued reference to Fig. 6, it should be noted that in addition to the control or logic signals provided by switches SlF and Sp, these switches can also be utilized to disconnect any and all loads from the power source that is supplying power to terminal 168. The outputs of switches SlF
and Sp are also fed to OR gate 214 and then to as many electri-cal loads as desired. When switch SlF is eventually opened,power continues to be supplied to control system 164, and to any other selected loads, through lens movement actuated switch Sp- However, when variable focus lens 166 is eventually returned to its park position, switch Sp is opened and all electrical loads that are receiving power through switch Sp and terminal 168 are disconnected.
If control system 116 depicted in Fig. 5 focuses variable focus lens 118 on a subject to be photographed and a camera operator is able to v.iew that subject ag focusing 2S is taking place, as in a s.ingle lens reflex camera, sai.d camera operator may want the option of being able to prevent a picture from being taken after focusing is complete and prior to the initiation oE a film exposure cycl~. The focus control system depicted in Fig. 7 modifies the focus control system dep.icted in F:i.g. 5 such that switch Sl is replaced by :

two switches or, as an alternative, by a single switch having two stages. One switch or stage is primarily for the control of focusing and the other switch or stage is primarily for the control of picture taking.
In Fig. 7, focus ~ontrol system 216 incorporatiny a two~stage switch, one stage primarily for lens focusing and the other stage primarily for controlling a film exposure cycle, and utilizing variable focus lens 218 movement outside of its normal focusiny range, in accordance with a preferred embodiment of the present invention, :is depicted. In control system 216, a source of electrical power (not shown) is supplied to one terminal of manually ac~uated, spring force biased, single pole switch SlF, to one terminal of manually actuated, spring force biased, single pole swi-tch SlT and to one terminal of lens movement actuated single pole switch Sp throuyh terminal 220, to which said source of power is connected. Switches SlF and SlT are mechanically linked to one another to form a two-staye switch such that switch SlF
must be closed before switch SlT can be closed. Either signal SlF or SlF will appear at the output of switch SlF
when said switch SlF is actuated. Siynal SlF will appear at the output of switch SlF when switch SlF is closed and signal SlF will appear at the output of switch SlF when said switch SlF is opened. ~Similarly, either ~ignal SlT or SlT
will appear at the output of switch S1T when said switch SlT
is actuated. Signal SlT will appear at the output of switch SlT when switch SlT is closed and siynal SlT wilL appear at the output of switch SlT when said switch Sl,l, is opened.
Alsol either siynals Sp or Sp will appear at the output of switch Sp when said switch Sp i5 actuated. Siynal Sp will Z45~i appear at the output of switch S when switch S is closed and signal S will appear at the output of switch Sp when said switch S is open.
Switch SlF primarily controls the automatic focusing of variable focus lens 218. When switch SlF is closed for focusing purposes thereby generating signal SlF at its output, AND gate 222 is rendered conductive if lens movement actuated switch Sp is open or if lens 218 is in its park position as previously discussed. If said switch Sp is open, signal Sp will appear at the input of AND gate 222 rendering said AN~
gate 222 conductive when said signal Sp is combined with signal SlF. When AND gate 222 is rendered conductive, range~
finding means 224 is activated so that it can determine the distance to a subjec~ to be photographed, said rangefinding means 224 functioning in a manner similar to that of rangefinder 14 described above and depicted in Fig. l. ~The output from AND gate 222 also renders latching OR gate 226 conductive. Latching OR gate 226 will remain conductive even if the input from AND gate 222 is removed, said OR gate 226 being rendered nonconductive only when switch SlF causes multivibrator 228 to generate a single reset pulse when said switch SlF is actuated to its closed position. The output of latching OR gate 226 is fed to the input of AND gate 230, said ~ND gate 230 being held nonconductive until focusing means 232 has caused the positioning of variable focus lens 2l8 to the correct subject-in-focus position and switch SlT
has been actuated to its closed position.
After the distance to a subject ko be photographed has been determined by rangefinding means 224, a range complete ~ignal is sent to latchiny OR gate 234 and the output of . . . .

latching OR gate 234 is transmitted to focus control means 232 to initiate variable focus lens 218 focusing. Latching OR gate 234 maintains a focus initiate signal to focusing means 232 after focusing movement of variable focus lens 218 has caused the actuation of switch Sp to its closed position which renders AND gate 222 nonconductive and deactivates rangefinding means 224 together with its focus initiating output. Focus control means 232 functions in a manner similar to focus control 35 described in some detail above and depicted in Fig. 1. Focus control means 232 sends drive forward signal 236 to drive motor 238 commanding said drive motor 238 to drive lens mount 240 together with variable focus lens 218 to the correct subject-in-focus position, said in-focus position to be sensed by lens position sensing means similar to that in said focus control system 35 (Fig. 1). Once focuslng is complete, focus complete signal 242 is trans-mitted to AND gate 230. AND gate 230 will remain in a nonconductive state until switch SlT is actuated to its closed position for the purpose of initiating a film exposure cycle. However, if a camera operator has determined that he does not want to initiate a film exposure cycle after focusing is complete, he would merely release or open switch Sl~, which would return variable Eocus lens 218 to its park position or to its switch Sp open position. Movement of variable focus lens 218 to its park or Sp open position under these conditions occurs hecause signa:Ls SlF and SlT are present at the input of AND gate 244 when switches SlF and SlT are in their open positions, and signal Sp is already present at the input of ~ND gate 244 because switch S was actuated to its closed 3() position when varia~le focus lens 218 was moved toward lts ~ ~Z2~5~i normal focusing range. In addition, there would be an outpu~
from inverter 245 because AND gate 246 would be in a noncon-ducting state due to a lack of an exposure initiate signal from OR gate 247. The function of AND gate 246 is to prevent variable focus lens 218 from being moved back to its initial state before a film exposure cycle is complete. With signals Sp, SlF, SlT and an output from inverter 245 present at the input of AND gate 244, said AND gate 244 is rendered conductive and transmits a reverse drive signal to drive motor 238 through ]0 OR gate 248, and said drive motor 238 drives lens mount 240 toward the lens 218 park position to the point where switch Sp is actuated to its open position by said lens mount 240 movement in a manner similar to that in control system 10 described above and depicted in Figs. l and 2. When switch S is eventually actuated to its open position, signal Sp will disappear from its output and AND gate 244 will be rendered nonconductive thereby shutting off the reverse drive signal to drive motor 238. At this point, variable focus lens 218 is in its park position or in the position at which switch Sp is open.
IE, on the other hand, switch SlT is actuated to its closed position when focus complete signal 242 is present at the input of AND gate 230, signal SlT will appear at the output of switch SlT and AND gate 230 will be rendered con-ductive. The output from AND gate 230 causes latching OR
gate 250 to conduct ancl the output from said latching OR gate 250 causes OR yate 247 to conduct. The output from OR gate 247 actuates a shutter mechanism which exposes and subsequently initiates tlle processing of an instant developing Eilm such as that utilized :in the self-processinq film camera merltiorl~!d 245~

above. In a camera where self-processing fllm is not utilized, the output from OR gate 247 would merely trigger a conventional, elec-trically actuated shutter mechanism. Once processing is complete, or in the case of a nonself-processing film camera, once the shu-tter mechanism has been fully actuated, shutter actuation completion or film processing complete signal 252 is sent to AND gate 254. If switch SlF has been released or actuated to its open position by a camera operator, signal SlF
will be generated at its output and AND gate 256 will be rendered conductive because latching OR gate 226 is still in its conductive state and the output from said OR gate 226 is present at the input of said AND gate 256 together with said signal SlF- AND gate 254 will be renderéd conductive upon receipt of completion signal 252 because AND gate 256 has been rendered conductive by the actuation of switch S1~
to its open position and signal S is already present at the input of said AND gate 254 because switch Sp was actuated to its closed position when variable focus lens 218 was moved toward its normal ~ocusing range. When AND gate 254 is rendered conductive, a reverse drive signal is sent to drive motor 238 through OR gate 248 which causes said motor to drive lens mount 240 toward its initial or park position until switch Sp is actua-ted to its open position. When swltch Sp is eventually actuated to its open posi-tion, signal Sp will disappear from its output and gate 254 will be rendered nonconductive thereby shutting off the reverse drive signal to drive motor 238. At this point, variable focus lens 218 is in its park position or in the position at which switch Sp is open.

~'Z'~55 If switch Sp had been in its closed rather than in its open posi-tion when switch SlF was initially closed, AN~
gate 222 would not have been rendered conductive and focusing by focus control means 232 would not have occurred. Swi.tch Sp would be in said closed position if variable focus lens 218 had been manually focused by a camera operator. In order to initiate a picture taking sequence in this situation, switch SlT must be closed. With switches S1T and Sp both closed, signals S1T and Sp would appear at the input of gate 258.
There would be an output from inverter 260 because there would be no output-from latching OR gate 226 due to the lack of an output from AND yate 222. An output from AND gate 258 renders latching OR gate 262 conductive, said OR gate 262 remaining in its conductive state until it is reset as pre-viously discussed. An output from latching OR gate 262 renders OR gate 247 conductive which, in turn, initiates a film exposure and processing cycle in the case of a self-processing film camera or merely actuates a conventional, electrically actua-ted shutter mechanism in the case of a nonsel--processing film camera.
Vpon completion of film exposure or of film exposure and processing, each of which are herein referred to as a film exposure cycle, whichever the case might be, completion signal 252 will render AND gate 254 conductive if switch SlF
has be~n actua-te~d to its ope~n po~ition. W.ith swltch Sl~, in its open posit:ion, s.ignal SLF appe~ars at its output and at the input of AND gate 264. When siynal SlE, appears at the illpUt to AND gate 264, sa:id AND gate 264 will. conduct because th~ ou-tput from previously latched latching OR gate 262 is 3~ also ~.)res~nt: at the .i.nput. t.o sai.d AND gate 264. The OUtpllt z;~

of conducting AND gate 264 will appear at the input of AND gate 254 when OR gate 257 is rendered conductive by an output from said AND gate 264. Signal Sp is already present at the input of AND gate 254 because switch Sp was actuated to its closed position when variable focus lens 218 was moved toward its normal focusing range. When AND gate Z54 is rendered con-ductive, a reverse drive signal is sent to dri~e motor 238 through OR gate 248 which causes said drive motor to drive lens mount 240 toward its initial or park position until switch Sp has been actuated to its open position by said lens mount 248. OR gatc 248 would also be rendered conduct~ive by AND gate 244 because if switch SlF is open, switoh SlT must also be open and therefore signals SlF, SlT, and Sp together with an output from inverter 245 will appear at the input of said AND gate 244, rendering said AND gate 244 conductive.
There will be an output from AND gate 246 when a film exposure cycle is complete which will render said AND gate nonconductive which will result in an output from said inverter 246. When switch Sp is even-tually actuated to its open position, signal Sp will disappear from its output and AND gates 244 and 254 will be rendered nonconductive, thereby shutting off the reverse drive signal to drive motor 238. ~t this point, variable focus lens 218 is in its park position or in the position at which Sp is open.
With continued reference to Fig. 7, it shou~d be noted that in addition to the control or logic signals pro-vided by switches SlF and Sp, these switches can also be utllized to disconnect any and all loads from the power source that is supplying power to terminal 220. The outputs of switches SlF and Sp are also fed to ()R gate 266 al-d then -to as many electrical loads as desired. When switch SlF is eventually opened, power continues to be supplied to control system 216, and to any other selected loads, throu~h lens movement actuated switch Sp- However, when variable focus lens 218 is eventually returned to its park position, switch Sp is opened and all electrical loads that are receiving power through switch Sp and terminal 220 are disconnected.
GENERAL CONSIDERATIONS
A variable focus lens includes both fixed and movable lens elements for variable focus lens focusing. In a conventional variable focus lens, the movable lens element is movable between both ends of its focusing range for focusing purposes. In such a conventional lens, movement of the movable lens element a significant distance outside of its normal focusing range would normally bring said movable element into physical contact with a relatively fixed lens element. The focal characteristics of a conventional variable focus lens must be modified to obtain additional clearance between fixed and movable variable focus lens elements in order to incorpor-ate the inventive concept of the present invention.
Lens actuated switch Sp, whlch may be of themechanical or solid state type or some combination of each, may be dir~ctly actuated by lens movement outside of its normal .focusing range as described above or may be indirectly actuated by means that sense or react to such lens movement.
The variable focus lens control systerns depicted herein are functionally represented in but one of a number of possible alternate representa-tions. In addition, these functions are not necessarily represented by the least number of functional blocks or the actual manner in which these 3~1;Z29~5~

functional blocks must be combined. AND gates, OR gates, latching OR gates and inverters are the basic functional blocks that are utilized in the functionally represented control systems depicted herein. An AND gate block will have an output so long as all of its inputs are present. ~n OR gate block will have an output so long as any of its inputs are present.
A latchiny OR gate block continues to have an output once any inpu-t is present, even when all such inputs are removed. The output from a latching OR gate can only be removed by rese~ting said latching OR gate after all inputs have been removed in a manner such as that described above. An inverter will have an output whenever it has no input and will have no output when-ever it does have an input.
Switches SlF and S1T depicted herein have been described as either two switches or a single switch having two stages that are mechanically interlocked and are spring force biased to their open positions such that the switch or stage representiny switch SlF must be actuate~ to its closed position before the switch or stage representing switch SlT
can be actuated to :its closed position. An alternate arrangement for switches Slp and SlT might be to permit either switch SlF or SlT to be actuated to its closed position first. However, the output from switch SlT would be electri-cally inhibited until there was an output from switch Slp.
Sw:itches SlF and SlT, whether two switches or two stages of a sinyle switch, are mounted on a camera housing such that said switch or switches are readily accessible for manual actuation hy a camera operator.
The term normal focusing range as used herein means that focusing range that is actually being utilized by the ~L~Z2~i5 variable focus lens, and said normal focusing range may be equal to or less than the complete focusing range of said variable focus lens.
It will be apparent to those skilled in the art ~rom the foregoing description of my invention that various improvements and modifications can be made in it without departing from its true scope. The embodiments described herein are merely illustrative and should not be viewed as the only embodiments that might encompass my invention.

Claims

THE EMBODIMENTS OF THE INVENTION IN WHICH AN EXCLUSIVE
PROPERTY OR PRIVILEGE IS CLAIMED ARE DEFINED AS FOLLOWS:

1. A focus control system for use in a camera having an image plane and comprising:
means for selectively coupling said camera to a source of electrical energy;
a lens mounted for displacement over a given operational range wherein it serves to focus images of subjects positioned within a normal range of distances at said image plane, and also for displacement outside of its operational range into another range wherein it does not focus images at said image plane, said lens being normally located within its other range when said camera is inopera-tive;
means for producing a signal indicative of the position of a subject within said normal distance range;
and drive means responsive to said signal for effecting the movement of said lens from its other range into its operational range to focus an image of the sub-ject at said image plane.

2. The system of claim 1 wherein said drive means includes means for automatically returning said lens to its other range subsequent to its focusing an image at said image plane.

3. The system of claim 1 including means for sensing when said lens has moved from its other range toward a focusing position within its operational range under the influence of said drive means whereby said sensing means may control the operation of a selected camera function.

44 9. The system of claim 3 wherin said sensing means is arranged to sense when the said lens has moved from its other range before said lens has reached its said operational range.

5. The system of claim 3 wherein said sensing means additionally senses when said lens returns from its operational range to its other range under the influence of said drive means whereby said sensing means may be utilized to control the operation of a selected camera function at such time.

6. The system of claim 5 wherein said sensing means senses that said lens is returning to an inoperative position when said lens is in its said other range.

7. The system of claim 2 including means for sensing when said lens returns from the said operative range to its other range under the influence of said drive means whereby said sensing means may be utilized to control the operation of a selected camera function.

8. The system of claim 1 wherein said coupling means serves to energize both said signal producing means and said drive means with power from the source of electri-cal energy.

9. The system of claim 2 wherein said coupling means includes a manually accessible actuator mounted for displacement between a normally inoperative position and a second position, means for urging said actuator toward its said normally inoperative position and a normally non-conductive first switch operably associated with said actuator so as to he rendered conductive to energize said drive means as said actuator is displaced from its said inoperative position to its said second position and again non-conductive when said actuator is returned to its said inoperative position under the influence of said actuator urging means, and wherein said drive means includes a second normally non-conductive switch and means responsive to the movement of said lens from its said normally inoperative position towards its said focus-ing position within its said operational range for coupling said drive means to the source of electrical energy thereby effecting the return movement of said lens to its other range after said lens has served to focus an image of the subject at the image plane and under conditions when said actuator has returned to its said inoperative position rendering said second switch non-conductive prior to said lens returning to its other range.

10. The system of claim 1 wherein said camera additionally includes an actuable exposure shutter and wherein said coupling means includes a manually accessible actuator mounted for displacement between a normally inoperative position through a second position to a third position, means for urging said actuator towards its said normally inoperative position, a normally non-conductive first switch operably associated with said actuator so as to be rendered conductive to energize said drive means when said actuator is displaced from its said inoperative position into its said second position and again non-conductive when said actuator is returned to its said inoperative position under the influence of said urging means and a normally non-conductive second switch operably associated with said actuator so as to be rendered conductive to actuate said shutter when said actuator is displaced from its said second position into its said third position and again non-conductive when said actuator is returned to its said inoperative position whereby said lens is displaced by said drive means from its other range into its operational range, responsive to said actuator being displaced from its said inoperative position into its said second position and back to its said inoperative position, to effect the focusing of said lens without causing said shutter to be actuated.

11. The system of claim 8 wherein said signal producing means is automatically responsive to being energized from the source of electrical energy and said camera additionally includes an exposure shutter and wherein said coupling means includes a manually accessible actuator mounted for displacement between a normally inoperative position through a second position to a third position, means for urging said actuator towards its said normally inoperative position, a normally non-conductive first switch operably associated with said actuator so as to be rendered conductive to energize both said signal producing means and said drive means as said actuator is displaced from its said inoperative position into its said second position and again non-conductive when said actuator is returned to its said inoperative position under the influence of said urging means and a second normally non-conductive switch operably associated with said actuator so as to be rendered conductive to actuate said shutter when said actuator is displaced from its said second position into its said third position and again non-conductive when said actuator is returned to its said inoperative position whereby said signal producing means is rendered operative and said lens is automatically displaced by said drive means from its other range into its operational range, responsive to said actuator being dis-placed from its said inoperative position into its said second position and back to its said inoperative position, to effect the focusing of said lens without causing said shutter to be actuated.

12. The system of claim 2 wherein said camera additionally includes an actuable exposure shutter and wherein said coupling means includes a manually accessible actuator mounted for displacement between a normally inoperative position through a second position to a third position, means for urging said actuator towards its said normally inoperative position, a normally non-conductive first switch operably associated with said actuator so as to be rendered conductive to energize said drive means when said actuator is displaced from its said inoperative position into its said second position and again non-conductive when said actuator is returned to its said inoperative position under the influence of said urging means and a normally non-conductive second switch operably associated with said actuator so as to be rendered conductive to actuate said shutter when said actuator is displaced from its said second position into its said third position and again non-conductive when said actuator is returned to its said inoperative position whereby said lens is displaced by said drive means from its other range into its operational range and back to its other range responsive to said actuator being displaced from its said inoperative position into its said second position and back to its said inoperative position, to effect the focusing of said lens without causing said shutter to be actuated.

13. The system of claim 1, further comprising:
a shutter; and energizable first means for determining the distance between said camera and a subject for producing a signal indicative of said distance and, responsive to said signal, for effecting the movement of said lens from its other range to a position within its operational range at which the image of the subject is in focus at said image plane, for then actuating said shutter and for sub-sequently automatically returning said lens to its other range.

14. The system of claim 13, wherein said lens may be focused manually, and comprising:
manually actuable second means for selectively energizing said first means from a source of electrical energy; and third means for sensing when said lens has been manually displaced from its other range into its said operational range and for then altering the response of said first means to effect actuations of said shutter without effecting movement of said lens.

15. The system of claim 14 wherein said third means includes means for altering the response of said first means to effect actuations of said shutter without determining the distance between said camera and the subject.

16. The system of claim 14 wherein said third means includes a normally non-conductive switch and means for rendering said switch conductive as said lens moves from its other range to its operational range and for rendering said switch again non-conductive when said lens returns to its other range.

17. The system of claim 14 wherein said second means includes a manually accessible actuator mounted for displacement between a normally inoperative position through a second position to a third position, means for urging said actuator towards its said normally inoperative position, a normally non-conductive first switch operably associated with said actuator so as to be rendered conductive, to energize said first means to determine the distance between said camera and the position of the particular subject, to produce said signal and for effect-ing said movement of said lens into its said focused position without actuating said shutter, when said actuator is dis-placed from its said inoperative position into its said second position and again non-conductive when said actuator is returned to its said inoperative position under the influence of said urging means and a normally non-conductive second switch operably associated with said actuator so as to be rendered conductive to actuate said shutter when said actuator is displaced from its said second position into its said third position and again non-conductive when said actuator is returned to its said inoperative position whereby said lens is displaced by said first means from its other range into its operational range, responsive to said actuator being displaced from its said inoperative position into its said second position and back to its said inoperative position, to effect the focusing of said lens without causing said shutter to be actuated.

18. The system of claim 17 wherein said second means includes means responsive to said actuator being returned from its said second position to its normally inoperative position for returning said lens from its focused position to its other range.

19. The system of claim 15 wherein said third means includes a normally non-conductive switch and means for rendering said switch conductive as said lens moves from its other range to its operational range and for rendering said switch again non-conductive when said lens returns to its other range.

20. The system of claim 1, wherein said means for deriving a signal indicative of the position of a subject comprises an encoder gear mounted in a fixed relation with respect to a portion of and having a known relationship with respect to the focal length of the lens, said encoder gear having equally spaced openings positioned in a fixed radial distance from a relatively fixed point, said openings cooperating with light emitting and light sensitive devices to periodically block and unblock light transmitted by said light emitting device to said light sensitive device, each combination of said light blocking and unblocking causing the generation of a pulse, the sum total of such pulses being representative of the focal position of the lens.

21. The system of claim 20, including means for stopping the movement of said lens in its operational range at which the subject is in focus, the stopping means comprising a relay actuated pawl, the actuation of said relay causing said pawl to engage and stop the motion of said encoder gear.

22. The system of claim 1, wherein said drive means comprises an electrical motor and said motor is mechanically coupled to said lens through a gear train, at least one gear in said gear train being mounted in a fixed position with respect to a movable portion of said lens, said fixedly mounted gear being mounted for rotation about the optical axis of said lens.