CA1122456A - Auto/manual focus control mode selector - Google Patents

Abstract

ABSTRACT OF THE DISCLOSURE
Manual/automatic focus control mode selecting means are provided for an adjustable focus lens camera having both manual and automatic focus controls wherein said mode selecting means causes said automatic focus control to position said lens to a known reference point when the automatic focus control mode is selected and, in addition, reduces the power requirements of said automatic focus control.

Description

59 ~ .Z~56 BACKGROU~ID OF TEIE INVENTION
__ 1. Field of the Invention _ ThP present inv~ntion relates to a control system for an adjustable focus lens in general/ and to such a control S system for an adjustable focus lens in a photographic camera, in particular.

2. Description_of the Prior Art Adjustable focus lenses and apparatus utilizing such lenses, such as photographic cameras, telescopes and the like are well known and ~heir operation well understood in the prior art. A camera having an~adjustable focus lens and having a focus control system coupled to said lens for automatically focusing imaye carrying 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 remote object, are also known in the prior art. A camera having such a ocus control system that utilizes acoustical energy to dete~nine the distance to an object remote from said camera is described in ~.S. Patent No. 3~522,764 to BIBER, et al.
A hidirectional focus control system, i.e., a foaus control ~ystem that, once commanded to do so, can move the movable elemellt of an adjustable focus lens in either o~
two directions from any initial position within the normal ocusiny range of said lens, or focusing purposes, is also known in the prior art. One examp]e o such a system is described in the above-mentioned BIBER et al. patent.
Another type of ocus contxol system for an adjustable focus lens i5 sornethimes referred to as a ~ 5~

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 a~ial directions, no lens focusing is performed as said element moves within its focusing range towards said reference point. A unidirectional focus control system of this type is significantly less complex than a bidirection-al focus control system because ik is unnecessary to continuously moDitor lens element movement as said element is moved toward said known reference point. The cost savings attendant a unidirectional focus control system over a bidirectional focus control system makes the Imidirectional focus control system attractive to the control system designer.
In a unidirectional focus control system, the focus control mode is selected by switch means actuated by adjustable focus lens movement ;~
outside of the normal focusing range of said adjustable focus lens. The manual focus control mode is selected by manually moving said lens to any position within its normal focusing range. The automatic focus control mode of said control system is selected by actua'cing said switch means by either manually moving said adjustable focus lens to a predetermined position outside of its normal focusing range or, in another embodiment thereof, by taking a picture when said lens is within its normal focusing range which will cause the automatic focus control system to position said lens to said predetermined position after a picture has been taken and fully processed.
Pocus control mode selecting means that does not rely on lens position are not provided. Because lens movement cmd mode selection are so interrelated, and because separate focus control mocle selecting means are not provided, a camera operator may fail to take note oF lens position and incorrectly assume that the camera is in its autornatic Focus control mode at the begi~l-ning of a picture taking se~luence which may result in the taking of at least one out-of-focus picture. Another potential problem is the possibility oE a camera operator draining the camera's battery by leaving .~ -2-15~

said camera in its manual focus control mode for an extended period of time. The nature of the unidirectional focus control system is such that leakage currents are drawn by the automatic focus control system when the manual focus mode is selected, and though relatively small, these leakage currents could be enough to render the camera's battery inoperative if the camera was left in its manual focus control mode and then stored for an extended period of time.
SUMMARY OF Tll~ INVFNTION
In accordance with the teachings of the present invention, a photographic camera having an adjustable focus lens and having a manual and an automatic focus control system requiring focusing movement of said adjustable focus lens from a reference position outside of its normal focus-ing range for proper operation of said automatic focus control, is provided with manual/automatic focus controL mode selecting means that reduces control system power requirements and, in addition, causes the automatic focus control system to position said adjustable focus lens to said reference position when the automatic focus control mode is selected.
More particularly, the present invention provides a photographic camera comprising: means for defining an image plane; means for directing scene light along a given optical path to said image plane, said directing means including a lens assembly having a lens mounted for displacement over a focusing range wherein various positions thereof respectively serve to focus an image at said imagc plane oE subjects positioned i.n var:ious locations w:ith:in a predetermined rallgc of subject distances, and :eor fllrther dispLace-ment erom its said :~ocwsing range into a second range wherein it does not sorve to ~ocus images at sa1.d image plane of subjects pos:i.tioned within said predetermined subject distance range; lens position sensing means actuatab:le between an init:ial state and a second state for sensing that said lens has moved a predetermined minimum distance from a reference position within the said second range o:~ said displaceab:Le lens; energizable first

-3 45~

means for determirling the distance between sald camera and the position of a particular subject within said focusing range for producing a signal i.ndicative of said particular subject distance; manually actuatable second means actuatable between an initial state and a second state for selecting the focus control mode of said camera; manually actuatable third means actuatable between an initial state and a second state for coupling said first means to a source of electrical energy when said second means is in its said second state; drive means responsive to the second state of said lens position sensing means for driving said lens to said reference position within its said second range and for actuating said lens position sensing means to its said initial state, and responsive to said subject distance signal for positioning said lens to the correct subject-in-focus position~
when said second means is in its said second state; means responsive to said drive means for producing a signal indicating that said lens has been focused on a subject to be photographed; and means responsive to said subject-in-focus signal for unblocking and blocking said optical path to produce an exposure interval.
The invention will now be described in greater detail with reference to the accompanying drawings, in which:
~igure 1 is a schematic diagram of an automatic and manual focus control system for an adjustable focus lens that is constructed in accord-ance with a preEerred embodiment oE the present invention; and F:igure 2 is a logic diagram oE the operation of the manual and aukomatic focus control system dep:ictecl ln l~:igure lo Referr:ing now to the draw:ings and specifically to Figure 1, a schematic d:i.agram of manua.l and automatic eocus control system 10 for adjustable :eocus lens 12, of self-processing camera 14, is depicted. In order to automatically focus adjustable focus lens 12, both mode select swi.tch SA/~ and switch Slr, must be actuated to their closed positions.
If switches SA/M and SlF are actuated to their closed positions, a portion ~ -4-of the source of power from an i.nternal camera 14 battery (not shown~ which is connected to terminal 16 will, in turn, be routed to the input of range-finder 18 through control logic 20 thereby activating said rangefinder 18.
When so activated, rangefinder 18 acoustically determines the distance to a subject to be photographed such as subject 22. When the distance to subject 22 has been determined, rangefinder 18 causes automatic focus control 24 to transmit a lens element posi.tioning force to the movable element of adjustable focus lens 12 causing said lens 12 to form an in-focus image of subject 22 at film plane 26 of said camera 14 when shutter mechanism 28 has been actuated to its open position by a signal from automatic focus control 24 through path 30. As mentioned above, camera 14 is of the self-processing type and therefore, once the actuation of shutter mechanism 28 is complete, film processing and transport cycle 32 is initiated. Tllis cycle initiates film processing and film movement out of said camera 14. If switch SlF is in its open position when film processing and transport cycle complete signal 34 is transmitted to automatic focus control 24, said automatic focus control 24 will cause the movable element of adjustable focus lens 12 to be driven to the point where lens movement actuated switch Sp is actuated to its open position by adjustable focus lens 12 movement through mechanical linkage 36.
In order to take a manually focused picture of a remote object with sel:E-processing camera 14, mode select switch SA/M must be actuated to its open pOs:iti.oll. W:ith lnode se].cct sw:itch SA/M actuatcd to its open posltion, sw:i.tches Slf~ and Sp are disab:Led. With switch SA/M so positioned, adjustable :eOcus lens L2 is focused by the rnanual movement oE focus wheel. 38. Once adjustable focus lens L2 has been focwsed to the correct subject-ln-:Eocus pos:ition, shutter mechanism 28 is actuatcd, for pi.cture taking purposes, by manually ac-tuated switch SlT to its closed position which will cause a shutte:c actuating signal to be sent to shutter mechanism 28 through path 40. When shutter mechanism 28 has been fully actuated, film processing and transport cycle 32 is then automatically initiated, said cycle ~unctioning in the same manner as when initiated in the automatic focus control mode. If lens movement actuated switch Sp was actuated to and left in its closed position by the manual movement of adjustable focus lens 12 by ~ocus wheel 38, automatic focus control 24 will sense said switch Sp closure through path ~2 when mode select switch 5A/~ is subsequently actuated *o its closed position and Gause said adjus-table focus lens 12 to be driven until switch Sp, which is mechanically linked to adjustable focus lens 12 through linkage 36, i~ actuated to its open position by adjustable focus lens l~ movement. Lens movement actuated switch Sp is actuated to its open position when said adjustable focus lens 12 moves a predetermined minimum distance outside of its normal focusing range. This predetermined distance corresponds to the reference position from which all auto-mat~c focusing is initiated by unidirectional automatic focus control lO. A loqic diagram of automatic and manual focus control system lO for ad~ustable focus lens 12 is depicted ;in Fig. 2.
In Fig. 2, focus control sy~stem lO including focus control. mode select sw.itch S~/M and utilizing adjustable focus lens 12 movernent outside of its normal focusing range in accor-dance with a preferred embodiment of the present invent.ion, is depicted. In control system lO, a source of electrical power from an internal battery (not shown) of camera 14 (Ii'ig. l) is supplied to one terminal of mode select switch SA/M and to one terminal of manually actuated, spring force biased, single pole switch SlT. In addition, when mode select switch S~jM
has been actuated to its closed position, power will be supplied to one terminal of lens movement actuated single pole switch Sp and to one terminai of manually actuated, spring orce biased, single pole switch SlF. Switches Sly and SlT are mechanically interlocked such that switch SlF
closes before switch SlT. Signal Sp will appezr at the output of switch Sp when switches SA/M and Sp are both closed.
Signal SlF will appear at the output of swltch SlF when both switches SA/M and SlF are closed. S~gnal SlF will appear at the output of swi~ch SlF when either switches S~/M or SlF are open. Signal SlT will ap~ear at the output of switch ST when switch SlT is closed and signal S1T will appear at the output of switch SlT when switch SlT is open. When signals ~p, SlF, or ST are generated, power will be supplied to loads other than those depicted in Fig. 2 through OR gate 43. The loads depicted in Fig. 2 will receive their power in accordance with the control system of Fig. 2.
In order to have control system 10 automatically focus adjustable focu3 lens 1~ on a subject to be photo~raphed, ~utomatic/manual mode select switch SA/M must be actuated to its closed position. If lens mo~ement actuated switch Sp is closed at the time that ~witch 5A/M is closed, control system 10 will cause adjustable focus lens 12 to be driven until said switch Sp opens. The operation o switch Sp under these conditions will be discussed in greater detail elsewhere herein. With mode select switch SA/M closed, an automatically focused picture will be taken by camera 14 (Fig. 1) by ~Z;Z~;i6 actuating switch SlF to its closed position. When switches SA/M and SlF are both closed, signal 51F will appear at the output of said switch SlF and at the input of rangefinder 18.
When signal SlF appears at the input to rangefinder 18, said rangefinder 18 is activated such that it determines the distance to a subject to be photographed, said rangefinder 18 functioning as it does in Fig. 1. Signal SlF al50 appears at the input to latching OR gate 44 which renders said OR gate 44 conductive. Latching OR gate 44 wil:L remaln conductive until reset, once there is an output rom said gate 44. A
latching OR gate will remain conductive once it has an output because said output is fed back into the input o said OR
gate which causes said gate to be maintained in its conductive state. The ~utput from gate 44 is removed only when said ga~e is reset by a pulse that is generated by one-shot multivibrator 45, said multivibrator generating said pulse when switch SlF
is initially actuated to its closed position while sw~tch SA/M
is closed. The output of latching VR gate 44 is fed to ~ND
gate 46, said AND gate 46 being held nonconductive until focusing means 24 has positioned adjustable focus lens 12 to the correct subject-in-ocus pos;tion.
After the distance to a subject to be photographed has been determined by rangefinder 18, a range complete signal i9 sent to latching OR gate 50 and the output of latchiny OR yate 50 is transmitted to focus control means 24 to initiate adjustable focus lens 12 focuslng. Latching OR
gate 50 maintains a focus initiate signal to focu~iny means 24 iE switch SlF is opened before focusing is c~mplete.
Focus control means 24 functions in the same manner as it does in Fig. 1. Focus control means 24 sends drive ~orward signal 48 to drive motor 52 commanding said drive motor 52 to drive lens mount 54 together with the movable element of adjustable focus lens 12 to the correct subject-in-focus position. Once focusing is complete, focusing complete signal 56 renders AND gate 46 conductive and the output from said ANn gate 46 renders OR gate 58 conductive. The output from OR gate 58 actuates a shutter mechanism which exposes and subsequently initiates the processing of an instant developing film such as that sold by the Polaroid Corporation under the registered trademark SX-70. In a camera where instant developing film is not utilized, the output from OR gate 58 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 60 is sent to AND gate 62. If spring biased open switch SlF has been released by a camera operator, signal SlF will be generated at its output and be present at the input to AND gate 64.
Signal SlT is already present at the input to AND gate 64 because switch SlT was never closed and therefore, said AND gate 64 will have an output that will be present at the input to AND gate 62. Signal Sp is alreacly present at the input to AND gate 62 because switch Sp was actuated to its closed position when adjustable focus lens 12 moved toward its normal focusing range. When AND gate 62 is rendered conductive by the presence of processing complete signal 60~ an output signal .~

~Z4S~

rom AND yate 64, and ~iynal S at its input, AND gate 64 will send a reverse drive signal.to drive motor 52 thxough OR gate 66 causiny said drive motor 52 to drive lens mount 54 until len~ actuated switch Sp has been actuated to its Open position by such lens mount 54 mo~ement. When switch Sp is actuated to its open position, signal Sp will disappear ~rom its output and gate 62 will be rendered nonconductive, thereby shutting off the reverse drive signal to drive motor 52. At this point, adjustable focus lens 12 i9 positioned a predetermined minimum distance outside of its normal focusing range and lens actuated switch Sp is in its open position, said lens position being the referénce point from which all automatic focusing is initiated. Control system 10 is now ready to again focus the movable element o adjustable focus lens 12 to another subject-in-focus position as determined by range~inder 18, if switch S1F is again actuated to its closed position.
To manually focus adjustable focus lens 12, focus control mode switch S~/M is actuated to its open position.
The movable element of adjustable focus lens 12 is then manually positioned to the correct subject-in-focus position by focus wheel 67. With mode swltch S~/M in its open position, switch SlT is ~ctuated to its closed position to initiate a picture taking sequence. Even though the mechanically interloclc~d switch SlF will be actuated to its closed position before switch S1~ is closed, the fact that mode select switch SA/M is in its open position will prevent signal SlF from be.ing generated at the output o~
switch SlE,. With switch SlT in its closed position, signal SlT will appear at the input to AND gate 68. There would ~e no output from latching OR gate 44 and therefore, AND gate 6 would be rendered conductive upon the arrival of signal SlT
at its input. An output from AND gate 68 renders latching OR gate 70 conductive, said OR gate ? remaining in its conductive state until reset by signal SlT. An output from latching OR gate 70 renders OR gate 58 conductive which, in turn~ initiates a film exposure and processing cycle in the case of a self-processing camera or merely actuates an electricaIly actuated shutter mechanism in th~
case of a nonself-proces~ing camera.
Upon completion of film exposure, or of film exposure and processing, whichever the case might be, adjust-able focus lens 12 is not driven to ~he point where switch Sp opens because of a lack of a reverse drive outpu signal from AND gate 62 to cause drive motor S2 to be driven to the point where said switch Sp opens. AND gate 62 is nonconductive in this instance because mode select switch SA/M is open which prevents signal Sp from being generated at the output of switch Sp. When 5pring force biased switch SlT is subse-quently released and i~ therefore actuated to its open position and with mode select switch SA/M also being in its open posStion, camera 14 (Fig. l) can then ~e stored for an extended period of time without draining the internal battery of said camera 14. If ~witch Sp'is left in its closed position and automatic/manual mode select switch S~/M is actuated to its closed positlon which is the position where the automatic focus control modc is ~elected, adjustable focu5 lens 12 will be driven to the point where lens movement actuated switch Sp ls actuated to its open position. Lens movement actuated switch Sp is driven to the position where said switch 5p is actuated to its open position when mode select ~LZ~4~6 switch SA/M is closed because AND gate 72 is, rendered conductive under these circumstances. AND gate 72 is rendered condl1ctive because signal Sp appears at its input due to switch S being closed, an output from AND gate 74 is present at its input because swltches Sl~ and SlT are spring force ~iased to their open positions and, an exposure initiate signal is not present at the output o OR gate 58 and at the output of AND gate 76. Because lens actuated switch Sp is actuated to its open position when mode select switch SA/Mis placed in its automa-tic or closed position, the internal battery o~ camera 14,(Fig. l) will not be drained by control system 10 evén if said camera 14 is stored for an extended perio~ of time while said mode seleat switch SA/~ remains in its automatic or closed po~ition.
DISCUSSION
Focus control mode select switch SA/~ in control systemA10 readily inaicates the focus control mode' of said control system 10. In addition to readily indicating the focus control mode of said control system 10, the inclusion of switch SA/M in said focus control system avoids the posslbility of electrical components in said control system draining the internal battery of camera 14 when said camera is stored for an extended period of time. I~ lens movement actuated switch Sp i8 in its closed pos.iti.on as the result o the movable element of adju~table focus lens 12 having been manually moved and left within the foausiny range of said len~ 12, there is no possibility o current being unnecessarily drained from said internal battery of camera 14, If switch SA/M is open when ~witch Sp is closed, current is precluded from flowing through said swi,tch Sp. If switch ~L~LZ2g~5~

SA~M is closed when switch Sp is closed, control system l0 will cause the movable element oE.lens 12 to be driven until lens 12 movement actuated switch Sp is actuated to its open position which will also preclude unnecessary current flow through said switch Sp.
Switches SlF and SlT are mechanically interlocked and collectively form a two-stage switch. As an alternate arrangement, the outputs from switches SlF and SlT could have been electrically interlocked. Switch stage 51F
is actuated to its closed position before switch stage SlT
can be fully closed. If switch SA/M is closed when switch stage SlF is closed, a subsequent ou~ut from switch stage SlT will not result in camera 14 shutter mechanism actuation by such switch stage SlT closure. Once there is an output lS from switch stage SlF, control system l0 inhibifs the subsequent output from switch stage SlT. However, an output ~rom switch stage SlT and no output from switch stage SlF will result in the actuation of shutter mechanism 2~ and in the processing and transport of exposed self-processing film. When shutter mechanism 28 has been actuated by switch stage SlT, it is assumed that the camera operator has previously positioned the movable element of adjustable focus lens 12 to the correct subject-in-focu.s position. Failure to so foc:us adiust;ab1e focus lens 12 prior to the actuation of switch stage SlT
will result in an vut-of-focus picture.
lt will be apparent to those skilled in the art from the ~oregolng description of my invention that various improvements and modifications can be made in it without dep~rting 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 (7)

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

1. A photographic camera comprising:
means for defining an image plane;
means for directing scene light along a given optical path to said image plane, said directing means including a lens assembly having a lens mounted for displacement over a focusing range wherein various positions thereof respectively serve to focus an image at said image plane of subjects positioned in various locations within a predetermined range of subject distances, and for further displacement from its said focusing range into a second range wherein it does not serve to focus images at said image plane of subjects positioned within said predetermined subject distance range;
lens position sensing means actuatable between an initial state and a second state for sensing that said lens has moved a predetermined minimum distance from a reference position within the said second range of said displaceable lens;
energizable first means for determining the distance between said camera and the position of a particular subject within said focusing range for producing a signal indicative of said particular subject distance;
manually actuatable second means actuatable between an initial state and a second state for selecting the focus control mode of said camera;
manually actuatable third means actuatable between an initial state and a second state for coupling said first means to a source of electrical energy when said second means is in its said second state;
drive means responsive to the second state of said lens position sens-ing means for driving said lens to said reference position within its said second range and for actuating said lens position sensing means to its said initial state, and responsive to said subject distance signal for position-ing said lens to the correct subject-in-focus position, when said second means is in its said second state;
means responsive to said drive means for producing a signal indicating that said lens has been focused on a subject to be photographed; and means responsive to said subject-in-focus signal for unblocking and blocking said optical path to produce an exposure interval.

2. The camera of claim 1, further comprising:
manually actuatable fourth means actuatable between an initial state and a second state; and said means for unblocking and blocking said optical path is additionally responsive to said fourth means.

3. The camera of claim 2, wherein said third means is the first stage and said second means is the second stage of a single two-stage switch.

4. The camera of claim 3, wherein the stages of said two-stage switch are interlocked such that said first stage must be actuated to its closed state before said second stage is actuated to its closed state.

5. The camera of claim 3, wherein an output signal from the first stage precludes an output signal from said second stage of said two-stage switch.

6. The camera of claim 1 further comprising fifth means (a) responsive to the actuation of said third means from its initial state to its second state when said lens positive sensing means is in its initial state indicating that said lens is in its second range and said second means is in its initial state, for effecting the energization of said first means, for effecting the displacement of said lens as a function of the determined distance to a position in the focusing range wherein it is adapted to focus an image of a subject to be photographed at said focal place, for effecting the operation of said unblocking and blocking means to define an exposure interval, and for then returning said lens to its second range; and (b) responsive to the actuation of said third means from its initial state to its second state when said lens position sensing means is in its second state indicating that said lens is in its said focusing range and said second means is in its second state, for effecting the operation of said unblocking and blocking means to define an exposure interval without effect-ing the energization of said first means and without effecting any displace-ment of said lens, said fifth means being subsequently responsive to the actuation of the second means to its initial state to effect the displace-ment of said lens to its second range.

7. The camera of claim 6, wherein said third means is additionally actuable into a third state and said unblocking and blocking means is responsive to the actuation of said third means to its third state and not responsive to the actuation of said third means to its third state and not responsive to the actuation of said third means into its second state when said lens position sensing means is in its initial state and said second means is in its initial state, and responsive to said actuation of said third means to its third state, not responsive to the actuation of said third means to its second state, and independent of the state of the lens position sensing means when said second means is in its second state.