WO1988002537A1 - Spherical pivoting actuator for read/record head - Google Patents

Abstract

An actuator system for a record and/or read head. The head is mounted in a structure which is movable in multiple directions around a pivot point (72). The head is mounted to an end of the structure opposite the pivot point. The actuator system is preferably used with a stationary media (5) which has a curved surface in the shape of a portion of a sphere with the center of the sphere being the pivot point of the actuator. The head is preferably an optical head with an objective lens (4) mounted at the end of an elongated actuator arm structure (70) which pivots around the pivot point. The remaining optical elements and the emitter (82) and detector (88) of the optical system are mounted farther up on the structure so that their weight is closer to the pivot point to reduce the inertia of the actuator arm.

Description

  
 



   SPHERICAL PIVOTING ACTUATOR
 FOR READ/RECORD HEAD
 This is a continuation-in-part of a patent application entitled "SWIVEL ACTUATOR SYSTEM", Serial
No. 916,743, filed October 6, 1986.



   BACKGROUND
 The present invention relates to systems for moving a record and/or read head across media, and particular, to systems for moving an optical head across a media.



   Most read/record heads today are used with either a disk or a magnetic tape. For disk drives, a magnetic media in the shape of a phonograph record is spun at high speeds while an actuator arm is swung across the media in the manner of a phonograph record arm. Typically, these heads will pivot on an arm about an axis parallel to the axis of rotation of the media and outside the perimeter of the media. Some head actuators use a linear movement to cross the spinning media. Optical disk drives are constructed in a similar manner except that the optical head is physically larger and need not be positioned as close to the media surface. For tape players, the tape itself is rolled past a stationary head.



   SUMMARY OF THE INVENTION
 The present invention is an actuator system for a read/record head. The head is mounted in a low inertia structure which is movable in multiple directions around a pivot point. The head is mounted to an end of the structure opposite the pivot point.  



   The actuator system is preferably used with a stationary media which has a curved surface in the shape of a portion of a sphere with the center of the sphere being the pivot point of the actuator. The head is preferably an optical head with an objective lens mounted at the end of an elongate actuator arm structure which pivots around the pivot point. The remaining optical components and the emitter and detector of the optical system are mounted farther up on the structure so that their weight is closer to the pivot point to reduce the inertia of the actuator arm.



   The objective lens is coupled via a plurality of straight extensions to a voice coil which is mounted farther up the actuator arm. The voice coil is used for focus and possibly tracking control by moving the objective lens. This positioning of the voice coil places its weight closer to the pivot point, thus reducing its inertia. The reduced inertia allows faster movement of the actuator arm with less power.



   In addition, the straight extensions coupling the focus and tracking voice coil to the objective lens angle inward from the voice coil to the objective lens.



  Thus, a large movement of the voice coil will produce only a small movement of the objective lens, enabling more precise control of the objective lens.



   The actuator arm is moved with an actuator coil which encircles the arm near the pivot point and is curved so that all points on the coil are an equal distance from the pivot point. This allows the coil to pass between magnets, which are similarly shaped, no matter where the actuator arm moves to. The projection of the actuator coil onto a plane normal to the axis of the actuator arm is preferably a parallelogram, with the corners of the parallelogram having angles of 45x and 135x, respectively. This ensures that force  vectors will be generated at an angle, giving orthogonal components which allow the generation of a force in any desired direction by appropriate activation of the coils or possibly magnets.



   The media itself has a curved surface with a shape corresponding to a portion of a sphere having the pivot point as the center of the sphere. The media can be either circular or rectangular in cross-section and could optionally be mounted or integrated into a plastic card or other means. Since the media is stationary with respect to the actuator arm, a higher density can be obtained on the media. The spacing of individual bits on the media can be uniform, and need not be varied as for disks which have a different rotation speed at the center of the disk compared to the periphery of the disk.



   The actuator of the present invention significantly reduces the number of moving parts necessary.



   By having the media stationary, the need for a motor to rotate the media is eliminated as well as the heat generated by such a motor. In addition, the variations in the distance between the media and the head are reduced since the media does not move, thereby reducing the amount of focus correction necessary. The shaping of the media as a curved surface increases the structural strength of the media and its resistance to bending.



   For a fuller understanding of the nature and advantages of the invention, reference should   be -made    to the ensuing detailed description taken in conjunction with the accompanying drawings.  



   BRIEF DESCRIPTION OF THE DRAWINGS
 Figure 1 is a front sectional view of a preferred embodiment of a pivoting actuator system according to the present invention;
 Figure 2 is a side sectional view of the embodiment of Figure 1;
 Figure 3 is a top view of the embodiment of
Figure 1;
 Figure 4 is a top view of the embodiment of
Figure 2;
 Figure 5 is a cross-sectional view showing one embodiment of Figure 1;
 Figure 6 is a top sectional view of the embodiment of Figure 5 along lines VI - VI;
 Figure 7 is a side view of the embodiment of
Figure 1 showing the pivot function and the (1-COS) element front view;
 Figure 8 is a top sectional view of the embodiment of Figure 7 along lines VIII - VIII showing the three alignment elements interfacing with the optional objective lens system retainer;

  ;
 Figure 9 is a side sectional view of an actuator arm showing the pivoting arrangement for the track-following and offset deflection means with the suspension for the deflection plate;
 Figure 10 is a top sectional view along lines
X - X of Figure 9 showing the deflection plate and the two X-Y voice coils;
 Figure 11 is a side sectional view of an actuator arm showing the (1-COS) elements with the track-following and offset deflection means suspended by a gimbal and voice coil arrangement for track-following;  
 Figure 12 is a bottom view of the embodiment of Figure 11 showing the gimbal arrangement for deflection means;
 Figure 13 is a side view of Figure 11 showing the front view of a (1-COS) element and the junction to the housing stem;
 Figure 14 is a top sectional view along lines
XIV - XIV of Figure 13 showing the arrangement of the three voice coils of the X Y Z alignment means;

  ;
 Figure 15 is a top view of a clamping means for a round media;
 Figure 16 is a side view of Figure 15 with a double-sided round media inserted;
 Figure 17 is the view of Figure 16 with a one-sided media inserted;
 Figures 18A-C show two individual planar voice coils in Figures 18A and 18B which are combined into a voice coil assembly as illustrated in Figure   18C;   
 Figure 19 shows a variety of possible forces which can be generated from the force components of the two coils of Figures 18A and 18B;
 Figure 20 shows some linear, circular and circular track offset movements which can be generated from the force components of the two coils of Figures 18A and 18B;
 Figure 21 is a top view of the pivot arrangement of Figures 22 and 23;
 Figure 22 is a side view of a pivot arrangement, spring loaded from the bottom, pivot dead-stop and anti-rotation means;

   ;
 Figure 23 is a front view of the pivot of
Figure 22;
 Figure 24 is a side sectional view showing a pivot pin to retainer cup interface;  
 Figure 25 is a side sectional view showing a pivot arrangement with a magnet to load the pivot and also to provide some rotation prevention means;
 Figure 26 is a top view of the embodiment of
Figure 25 showing the magnet and the permeable pivot shell;
 Figure 27 is a top view of the pivot arrangement of Figure 28;
 Figure 28 is a front view of a gimbal led pivot arrangement including a dead-stop and a pivot load magnet ring;
 Figure 29 is a front view of a pivot arrangement which has the pivot loaded from the bottom and utilizes a flexible bellows ring to prevent rotation of the pivot;
 Figure 30 is a side sectional view of a pin to retainer interface for use with higher inertias;

  ;
 Figure 31 is a side sectional view of a pin to retainer interface with a small pin tip and small relative motion;
 Figure 32 is a side sectional view of a pivot arrangement similar to the embodiment of Figure 25 except that it is loaded from the top by a magnet ring;
 Figure 33 is a side sectional view of a pivot pin to retainer cup interface with only small roll-off motion but essentially no relative motion;
 Figure 34 is a side sectional view of an individual clamping means with media interface for registration in both vertical and horizontal directions;
 Figure 35 is a side sectional view of a portion of the voice coil showing the (1-COS) elements;
 Figure 36 is a schematic diagram showing the principle of counter-mass balancing for a rotary drive;

  ;  
 Figure 37 is a schematic diagram showing the movement of the objective lens with several vertically displaced voice coils coupled together;
 Figure 38 is a sectional view along lines 38-38 of Figure 39, showing the tray bracket and media;
 Figure 39 is a front sectional view of an actuator system using a balance weight on top of the pivot for portable applications;
 Figure 40 is a top view of Figure 41;
 Figure 41 is a front view of an economy version actuator system for lower performance;
 Figure 42 is a top sectional view of the embodiment of Figure 43 along lines 42-42 showing the segmentation of the spherical media;
 Figure 43 is a front sectional view of a cylindrical spherical media arrangement with a air bearing pivot;
 Figure 44 is a side sectional view of a pivot showing an implementation of a pivot pin where the manufacturing technique used is deep drawing;

  ;
 Figure 45 is the view of Figure 44, with the load pin implemented by a flexible load means;
 Figure 46 is a side sectional view of Figure 47 along lines 46-46;
 Figure 47 is a top view of a pivot load spring with minute lateral force; and
 Figure 48 is a side sectional view of a plunger type solenoid mover operating against a bias spring.



   DESCRIPTION OF THE PREFERRED EMBODIMENTS
 Figure 1 is a side sectional view of an actuator system according to the present invention. A  pivoting actuator arm 70 moves about a pivot point 72.



  A first, free end 74 of the actuator arm is directly above a spherical media surface 5.



   Actuator arm 70 is moved with an actuator coil 2 which is mounted in a curved piece of potted
FIBERGLASS coupled to the actuator arm. Figure 18A shows a cross-sectional view of one section of the coil which is in the shape of a parallelogram. The other section is shown in Figure 18B, with the combination illustrated in Figure   18C.    Coil 2 is passed between magnet 11 and yoke 76 on one side and magnet 78 and yoke 80 on another side. The yokes provide a permeable return path for the magnetic flux. Magnet 76 is reversed with respect to magnet 78 so that additive forces are generated in coil 2. These magnets can be electromagnets or any other type of magnet.

  Because the coil is shaped as a parallelogram, with the portions passing between the magnets being at a 45x angle, force components in any direction can be generated by activation of the appropriate voice coils.



  The force components are shown in Figure 19.



   Any type of read/record head can be used in actuator arm 70. For purposes of illustration, an optical head with an objective lens 4 is shown which focuses a beam from a laser diode 82 which is reflected off of a mirror 84. The beam then passes through other optical components until it is focused by objective lens 4 onto media surface 5. The return beam is deflected by a beam splitter 3 through a lens 86 to a photodetector 88. The wire leads to photodetector 88 and laser diode 82, (1-COS) voice coils 7 and prime mover voice coil 2 are combined into a Kapton Flat cable 90 leading through the center of actuator arm 70 or outside arm 70 towards pivot 72. Near the pivot, flex motion is small and only a small service loop is  required to couple to a PC board 92 containing the control circuitry.



   Also connected to actuator arm 70 are three voice coils 7 which are coupled via straight extensions 94 and 96 to objective lens 4. Three voice coils are included to allow movement of the objective lens in three dimensions, the X, Y and Z directions. As can be seen, extensions 94 and 96 angle inward from voice coils 7 to objective lens 4 so that a large movement of the voice coils produces a small movement of the objective lens. This allows increased accuracy in the movement of the objective lens. The relative amount of movement of the objective lens to the voice coil is a (1-COS) function.



   Except for objective lens 4, the remainder of the optical elements are mounted higher up on the actuator arm to reduce the inertia of their weight.



  The closer these elements can be mounted to pivot point   2,    the less inertia they will cause, and thus the less power is required to move the actuator arm. The same principle applies to voice coils 7, which are mounted up away from end 74 of the actuator arm to lower their inertia. For minimal inertia, the optical components are mounted right next to the pivot above the actuator coils 2.



   The media 5 can be slid in through an opening 100 in the wall of housing 12. Actuator arm 70 is stationed on opposite side of opening 100 when the optical media is inserted or removed. A magnetic latch 132 with a shallow field and a permeable slug 134 on arm 70 could also be used. Prime mover voice coil 2 would pull arm 70 off latch 132 into the data area of the medium. When current is removed from coil 2 (such as by a switch activated by opening a drive door across opening 100), the coil will pull arm 70 up against  latch 132. A media container could also be employed for insertion and removal. Media 5 is positioned on a tray 8 with registration and clamping mechanisms as shown in more detail in Figure 16, discussed later.



   As can be seen from Figure 2, an internal frame 102 supports media tray 8 as well as the pivot arm assembly. Magnets 76, 78 and yokes 11, 80 are mounted to the exterior housing 12. Frame 102 is separated from exterior housing 12 with shock absorbers 10. A significant separation between interior frame 102 and exterior housing 12 is provided to allow isolation from large shocks. A relatively large air gap 13 is used to accommodate large excursions.



   To keep the weight low and also establish adequate magneto-motive force for the long air-gap, a   Neodymium-tron-Boron    magnetic material is used. Since the mass to be isolated (structure 70) is small, only relatively small excursions are required. Other magnetic materials will suffice for lesser performance.



   For proper operation, the polarity of the two magnet halves has to be uneven, plus on one side, minus on the other. The permeable portion of the magnetic loop can be iron material, coated against corrosion. This portion has to be separable for insertion of the stem and voice coil. To achieve shorter current rise times, copper rings may be employed encircling the magnetic flux path. This common practice may also be applied for the X, Y and Z voice coils in the voice coil deflection means 6. 
 For weight reduction, cobalt iron with a saturation level of about 23,500 gauss could be used. To lower inertia, the lower, thinner part of actuator arm 70 serves essentially only as a shading tube and the material could be aluminum or plastic material, or other lightweight means.  



   In addition to an application for an optical information and data storage and retrieval system, some other potential uses for the present invention are printers and optical scanners.



   The X, Y and Z alignment of the objective lens is implemented by a three-part translation means with essentially a (1-COS) function. Track-following is performed by the same means and/or by a tilting optical deflection assembly operated by a one or more voice coil arrangement or other suitable means with gimbal led or pivoted suspension. For X and Y alignment alone, only two mover means would be required.



   The system omits the conventional spindle and other costly carriage parts of the prior art.



   Although there are other possible applications, such as printers, character readers and others, the description will focus primarily on optical storage and retrieval systems. The system can be applied to all optical technologies, such as OROM, WORM and
Erasable. The media may be removable or fixed.



   For practical considerations, there is only one area of potential wear which is the swivel or pivot assembly. However, even in circular or spiral motion, only essentially rolling movement (rather than turning motion with its relative movement of surfaces) exists.



   For certain applications, a pivot as in Figure 30 or 31 with minute relative motion and perhaps lubrication may have to be used.



   The flex-leads are proven in existing products for long life. The X, Y and Z alignment and deflection means 6 experience only very slight bending stress to assure almost infinite life.



   A pivot retainer cup 104 shown in Figure 2 can be manufactured with ultra-high molecular weight polyethylene with six million molecular weight or a  dense high temperature polyimide as plastics. Both materials can be filled with graphite for permanent lubrication to maintain low friction. The high inherent damping of these materials will suppress mechanical vibrations. The dead band for servo operation is low.



  The system has very low audible noise. Porous phosphor bronze is another choice. A pivot pin 106 can be coated with hard nickel to assure low friction and good wear characteristics. Other materials are possible and, if needed, very long life lubricating means are in existence.



   The media can be of various shapes and different utilizations. The data surface will be spherical, with or without grooves for positioning and data information. The position information should preferably be permanent However, servoing of data is a possibility. Position information may-consist of arrangements of discernible features or pits from regular data related pits. Spherical media integrity is high.



  Flat media, by comparison, can be bent so that sensitive layers could be subjected to tensile or compressive forces degrading grain structure and other functional properties. Sensitive layers, such as seed layers or layers for phase change or magneto-optic media are examples. The media can have a round shape.



  For certain applications, operation may preferably be in spiral fashion and constant linear speed. To avoid excessive rotational speed, the inner diameter should not go below a certain minimum. The remaining area, unlike for conventional flat round disks, can be utilized for data also. The spherical shape of the media provides some surface protection since the concavity provides a recess against a flat surface. In circular operation, like hard magnetic disk drives, constant angular velocity is used sacrificing some data  capacity. For certain applications, transfer-frequency changes for different zones can be applied for increasing data capacity.



   The media can also be rectangular, either square or oblong or any shape. Square and particularly oblong media could be used where maximum capacity is desired but being constrained by a mandatory footprint to be compatible with existing drives. The motion can be back and forth. The moves would have short acceleration or deceleration ramps before achieving or after leaving plateau speed. In order to maintain a constant frequency for continual data transfer, small buffers would have to be used, which already exist for errordetection and error-correction. The square and oblong media's center could be data arranged in circles or spirals while the data in other areas could be arranged as linear, in smaller circles or in a spiral or any other arrangement. The media can be of different size, perhaps up to a practical limit.

  A penny or a silver dollar size could prove useful, for example, where a so-called optical card or a CD-ROM is to be used. If, however, an optical card with about credit card size is used, several spherical indentations could be spaced on both sides, front and back of the card in symmetrical fashion as to upper and lower surface for higher capacity. Particularly if the size of a penny or silver dollar was used, the use of a metal substrate for certain technologies may be indicated. This would allow well proven and extremely low cost coining manufacturing methods. For highest demands, low expansion Invar as a substrate could be used. Especially for nonremovable applications, glass or Cervit with a coefficient of thermal expansion of half a micro inch per degree Fahrenheit could satisfy the most demanding applications. Surfaces could also be lapped.  



   Since the media are stationary, only a. very small amount of vibrations will be transmitted.



  Furthermore, no heat source is placed under the media, assuring stable conditions. Smaller media are easier to process, transport and store. Higher yields and less defects can be expected.



   The media could have a hole or a bottom hole for registration A container can be used to improve portability. The corners of the container can be devised to withstand hard impact.



   The parts count is very low in comparison to conventional drives. The spindle drives, with electronics, costly drivers, bigger power supply, test, assembly and storage are eliminated. The carriage equivalent is greatly simplified. Tight tolerances are avoided. Parts are typically small. Large cost savings are realized. A disk drive by comparison has many more parts, which for the same storage capacity requires a larger envelope, more power, clean room assembly techniques, and precise assembly alignment procedures.



   There are many applications where the drive is accessing only a few sectors with a very low duty cycle. Here, a linear movement would prove very favorable. At idling times, the actuator will rest at some location on the media. Very minute current is required. To emphasize speed, one has to realize that many positions, a hundred or more, can be accessed from the same major track by merely tilting the highly responsive mirror 3. Overall, power is very small, and the controlling electronics could also go in standby mode, reducing power even further. Operation may be with internal battery and photovoltaic cells on the housing in certain instances. One application is for  data collection in remote areas. Typically, lowly utilized home computers may fall under this category.



   Circular or spiral motion, however, would use much less peak power than a hard disk drive. In a hard disk drive, the time to attain rotational speed has to be very short because heads are in contact with the disk. Gliding time on disk should be short to avoid damage. After gliding, the heads will fly and are separated from the media as in optical disk drives, where, however, the distance is much larger. For this reason, the optical drive will need much less peak power even for circular motion. Running power is only a small fraction of starting power in hard disk drives. Only a little more than running power is needed for an optical drive.



   Another important aspect is the low inertia and very low weight of the moving part (the actuator) and the inherent low friction of the pivot. Minute movements at the pivot will facilitate relatively large movements on the media surface. The weight of the drive is also very low. The load inertia of individual mass concentrations can be calculated by mass times distance from the pivot squared (mr2). The closer the mass is located to the pivot, the less inertia the same mass will have. In the future, a highly integrated, low weight optical means may be located near the pivot and fiberoptics will facilitate coupling to the objective lens for lowest inertia.



   The principle of the present invention has high upward mobility to apply the higher areal densities and technologies of the future. Since the media is stationary and no heat source is in close proximity, the functional behavior will be very stable. The actuator principle also eliminates many conventional vibration sources. The pivot has very high inherent  damping, almost isolating the moving parts from the tray structure. Vibrations play a key role for ultra-precise and responsive positioning. The media being stationary will also allow the use of the most stable glass substrates. The principle's merits will improve with higher areal densities of the future.



   When and if components for optical aiming are developed, the moving mass of the actuator arm or stem will be reduced further. Optical aiming means the use of electrically controllable lenses with variable focal length for focusing. The deflection means for the tilting function could be implemented in a similar fashion. Electrical calibration can be utilized and wider manufacturing tolerances are another one of the benefits.



   A multitude of rectangular, round or any shape media and sizes can be projected. For highest data transfer; a cylinder with a spherical surface could be employed. The actuator would spin around a high revolution air bearing pivot. A spinning head would be balanced by a symmetrical mass, or opposite pairs of optical heads could be used for parallel operation. The spherical surface could be continuous, segmented and also be removable by segment. The same spherical voice coil, single pivot principle would be applied. The air bearing could be a self-acting design similar to a herringbone construction. In larger systems a small peristaltic pump could provide air pressure for starting, if needed. A pressurized air bearing could, however, be used also. The bearing surfaces could be coated with the newer economical diamond-like surface treatment processes. No rotation prevention is required.

  Besides being spherical, the voice coil or mover means will have preferably a round shape and the  magnet and wiring arrangement will be more like a conventional motor.



   A balancing means, as shown, in principle, in
Figure 36 could be employed. A floating mass on the frame could be employed instead or in addition.



   For certain applications an actuator can be devised where the actual voice coil extends only on one side of stem, allowing sideways insertion into the magnetic circuit.



   Two or more drives could operate in tandem, either in parallel or mostly with the same electronics.



  Tandem operation could also cancel operational impact like in a boxer-motor. A combination of two could prove useful with a 3-1/2 inch half high envelope with one fixed, one removable. To address larger data bases, it will be more favorable to use several single pivot drives with a virtual buffer. Lower transfer rates could be used and back up is inherent for highest reliability.



   It is the object of the present invention to reduce the cost of optical storage and avail it to a larger user base. The elimination of the conventional spindle and associated components, the simplification of the carriage means, and manufacturing and operation with low inertia for low power consumption give the principle a decisive cost advantage. The pivot actuator and spherical media concept has several other advantages, which are a large market, high reliability, low weight and low audible noise.



   The principle of the present invention has very favorable functional features to serve highest areal densities of the future. To highlight the application of the principle, two cases perhaps emphasizing some extremes are displayed. One would be an arrangement like in Figure 41. Another is shown in Figure 43,  utilizing a cylinder structure with a spherical surface, an air bearing pivot, multiple heads, high rotational speed, rotor forces induced, and data transmitted through short distance in air. A compact 5-1/2 inch cylinder, 2 inches high, could yield well over 4
Gbytes or even 10 Gbytes in the future at 120 or 300    2
Mbytes/inch . Applications may be radiation count,    scientific data processing, and others. The rotor would consist of a permeable material and/or permanent magnets.

  The stator coils would be overlays facilitating both rotation and lateral movement for track accessing. Between or beyond these two extremes, an almost limitless spectrum of applications exists.



   All existing and future anticipated optical technologies, besides X-ray, can be applied to the present invention. The next generation of optical storage may be frequency domain,   i.e.,    photon gating and multiple color lasers may be used. A second harmonic generator could quadruple bit densities in the   future.   



   The optical card for identification is a WORM application. Every identification is different and individual imaging is required. One use may be medical records. The card can also be used for erasable media.



  It remains to be seen whether a small round media instead of the optical card will prove to be more practical and popular.



   To access a relatively small flat surface, a second set of movers could be added to the (1-COS) system. In its simplest form, only a stationary (1-COS) system without pivot and spherical voice coil could be devised. Here, the use of narrow strips with alignment notches on the sides and the length of a credit card may prove popular. Several contiguous areas could be accessed. Spherical indentations can also be applied to strips with offsets on each side so that centers  would not coincide. If multi-color laser beam techniques become available, much higher capacities and speeds become feasible. To gain perspective on average access time, it has to be considered that much shorter strokes are required in the present invention for the same amount of data as recorded on magnetic discs because of higher areal densities. The speed/power relationship is also very favorable.

  The actuator arm of the present invention is also faster because it does not need to wait for rotation of the media to access a particular sector, it simply moves directly to that sector.



   The excursion clearance of the tray structure to the housing can be observed in Figures 1, 2, 3 and 4. The placement of the connectors for power and signal lines will depend on the application. A stop means 16 is provided to soften impact of stem on overtravel should the system be out of control.



   An opening 100 in the housing for insertion and removal of the media is provided. The media can also be devised for stackability. A small recess at the bottom will reach over the upper rim or contour to prevent sideways movement when placed on each other.



   Figure 11 shows the preferred embodiment of the X, Y and Z direction alignment means with the (1-COS) elements. The deflection means 17 (for trackfollowing or offset) is also shown. A glass plate, a grating, or other suitable optical means 108 is suspended from the actuator arm structure by way of a gimbal 18. The gimbal can also be cylindrical, mounted on top of the voice coil arrangement. Stop means 110 limit the plate excursion upon excessive shock.



  Plate 108 also preferably connects to at least one element voice coil arrangement 19 which can facilitate track following and track-to-track movement for  circular, spiral, linear, or any movement. A magnet ring of   Neodymium-Iron-Bordn,    or other suitable material 20 and the permeable loop element 21, preferably
Cobalt iron for low weight, comprise the magnetic circuit. The magnetic circuit can be devised for magnetization of ring in axial or radial direction.



  The upper part 6 of the (1-COS) elements are spot-welded (or joined with other suitable joining means) at position 22 (also shown in Figure 13) to the actuator arm housing. The material may be stainless steel or beryllium copper. The (1-COS) elements are moved with voice coils 118, 120 and magnets 122, 124.



   Figure 35 explains the function of the magnetic circuit for the (1-COS) element. One of the magnet rings and special washers could be eliminated, however, the force constant would be cut in half. Returning to Figure   Il,    the lower extension 112 of the (1-COS) element is connected to the objective lens system retainer 23 by a swivel or pivot arrangement 24 loaded by a circular spring 25 or other suitable means of joining. Lower extension 112 includes a flat member 114 and a reinforcement wedge 116. Wedge 116 adds stiffness to structure 114. All three of elements 23, 24, 25 comprise a system which performs the X, Y and Z direction alignment. This same system can also provide small offsets in the X-direction (lateral to track) by tilting. Track following can also be facilitated with this system, up to a point.



     Figures'    5, 6, 7, 8 and 9 show essentially the same element, except that the interface to the stem is implemented by a swivel allowing a wider operating range since the spring of (1-COS) element is longer.



   Another way would be to permanently attach the pivot point to the actuator arm, or stem is by resistance welding or similar techniques and by extending  the spring portion 6 to the top portion of the actuator arm close to the pivot. The deflection means (in its function similar to the conventional mirror tilt) of
Figure 9 is suspended by a swivel 26 mounted into a cup formed by the permanent pivot of the (1-COS) elements.



  Plate 108 of the deflection means shown in Figure 10 is inserted into the optical path through an opening 27 in the stem housing. This deflection means is devised to operate with the same magnet ring or rings as the X, Y and Z alignment means. A mover as in Figure 48 can be used. The voice coils are stationary on the stem and a plunger of a small magnet or permeable material transmits the force to the (1-COS) element. The system may also operate against biasing springs in one or both ways. The biasing means could also be implemented with a high damping means. A center position with essentially no bias can also be utilized.



   A resting stop facilitating a position at an upper end of the operation range, i.e. farthest away from media, could be employed while the drive is not operating. Due to the high mechanical integrity of the media, lower focusing requirements can be expected.



  The (1-COS) function means that a relatively large excursion at the voice coil (or piezo crystal or other suitable mover means) results in a relatively small or finely resolved motion at the lower end interfacing with the objective lens retainer.



   Damping means could be employed in critical areas of the stem system besides the shock isolation and stop means for the drive. If the magneto-optic recording technique is used, an erase coil 28 as shown in Figure 9 can be attached to the objective or pick-up lens retainer.



   Figure 15 shows the top view of a clamping means for round media. Initially, a clamp lever 29 is  lifted by a spring 30 backing against the excenter means 31 which is also in the unloaded position.



   An insertion means 32, here called media retainer, gets inserted with the media. The guided retainer in turn gets inserted through an opening of the housing onto the tray with the registration pins 33 for
X and Y alignment of the media. Appropriate recesses 34 in the media extension ring engage with the registration means, here pins 33. Registration means 33 can be implemented with coined projections on the tray.



  Since the retainer has adequate clearance, it will float, except for an extraction spring 35 which will hold it against the media.



   Once the media is engaged with the registration means, the excenter 31 will force the clamping lever downwards against the tray 8. A properly devised spring 36 engages with the media, forcing the media against the pins; while clamping it against the tray for control in the Z direction.



   The excenter 31 has an angular overtravel and also an overtravel spring 37 in the clamping lever in order to retain position and allow for large parts tolerances. To isolate the excenter from the drive housing, overtravel clearances in the lever coupling means in all directions are provided. A clamping and registration means to also accommodate different sizes and shapes for spherical media can be devised with passing or clearing recesses. The spherical media and tray will have high spots engaging the tray in the area of the engagement protrusions.



   Figure 16 is a side view of Figure 15 and shows the application for dual-sided media 38. Also displayed are the spring-loaded engagement protrusions 39 to the media ring for clamping the media to the tray.  



   Figure 17 shows a similar arrangement for single-sided media 40.



   Figures 18A-C show individual planar voice coils 41 and the combined overlay into a functioning unit 42. A stem passes through the center. This stem is actuator arm 70 of Fig. 1. At least the leads for the voice coils will be passed to the swivel area and be connected via flex leads to a printed circuit board.



  For assembly purposes, the stem structure may be round,
U, H or of other convenient shapes. In Fig. 1, only portion 140 need be closed to shade the laser beam.



  The electrical connections to the optical alignment and deflection means may also pass through the stem into the vicinity of the swivel. In certain applications, however, these connections may interface with printed circuit boards situated below the magnet assembly.



  More than two layer pairs can be arranged, perhaps one more with a 90x offset, or two more with a 60x offset and so on. The voice coil assemblies can be implemented with copper or aluminum magnet wires or by multilayer processing as in thin film heads, or insulated laminates. A functioning unit of voice coils may only extend on only one side of the actuator arm.



  This is mandatory for the arrangement of Fig. 41, but could be used for the two-sided arrangement in Fig. 18.



   Figure 19 shows how any force components and relative directions are generated by changing the current amplitudes of the individual coils, or operating similar to pulse width modulation. Figure 20 shows, in particular, how linear, circular, spiral and track offsets are generated. It also shows the components 43 for circular or spiral motion once a rotational speed is attained. Here, centrifugal forces have to be contained or counteracted, depending on speed.  



   Figures 21, 22 and 23 show a pivot arrangement. A pin 44 with a small, round shape interfaces with a swivel or pivot retainer 45 allowing motion for degrees of freedom to describe a spherical motion of an objective lens to interface with a spherical media sur   face   
 The side view of Figure 22 shows a spring 46 loading the pivot while exerting little lateral force to keep force bias in the pivot low. A rotation prevention means 47 is also shown, consisting of an environmentally stable flex medium to minimize rotation.



  The prime mover voice coils 2 are capable of aligning the optics in the direction of the track, preventing rotation of the actuator arm about its own axis. This can be done by providing the voice coil more current in response to a rotation detected by the optical system.



  The need for rotation prevention depends on the particular application. The flex-lead close to the pivot is adequate for certain instances.



   Figure 23 shows a front view of the
C-structure 48 connecting the upper to the lower part of pivot. The dead-stop 49 prevents the swivel pin from moving out of the pivot retainer when extremely high shock is imparted on the system. The clearance from the stop to the bottom of the retainer is only a few thousandths of an inch For this reason, the dead-stop and the bottom of the retainer are shaped to maintain clearance in lateral operations of swivel.



   Figures 27 and 28 show a swivel or pivot arrangement with a gimbal 50 for control against rotation of the pivot. The loading of the pivot is implemented with a magnet ring 51. The planar offset 52 of the gimbal is optional.



   Figures 25 and 26 show a swivel arrangement whereby the loading is done by a magnet 53 which also  prevents rotation. The magnet protrusions are polarized plus and minus. The assembly will settle into the position of most favorable reluctance, thus re-zeroing into this position when rotational forces try to disturb its equilibrium.



   Figure 29 shows a pivot which is loaded from the bottom by a magnet ring. Rotation prevention is implemented by a suitably devised circular flex ring 54. The drive can also operate upside down.



   Figure 30 shows a pivot interface to the retainer cup for heavier inertial loads. Slight relative motion occurs and outside lubrication may enhance operation. The shape of the pin tip can be used for all approaches.



   Figure 31 is also a pivot interface. Relative motion occurs, however, little since the round tip of pivot pin is small.



   Figure 32 shows a swivel arrangement similar to Figure 29 except the loading occurs from the top.



  The difference may be functional and/or assembly philosophy.



   Figure 33 is a pivot interface showing the regular envisioned operation. No relative motion occurs, essentially only rolling motion. To prevent rotation, a pivot interface like a Philips screw driver or Allen wrench could be employed. The shape of the interfacing surfaces would have to be optimized for this application; lubrication may be indicated depending upon the application.



   Figure 34 shows individual clamping means for both lateral and vertical directions.



   Figure 35 shows the magnetic circuit assembly for the X, Y, Z alignment means and the generation of the forces.  



   Figure 36 shows, in principle, a floating mass 55 for balancing.



   Figure 37 shows, in principle, an additional set of movers for the (1-COS) system. The system can now access a small flat surface considerably larger than the one set system could. Flexible containment rings prevent rotation of individual segments, keep a favored center position and also allow slight lateral movements. Though the one mover system, as in Figure 11, can move laterally and also tilt the objective lens, it could not also focus the objective lens properly. Initially, smaller capacities could be accessed.



  In the future, when highest density techniques, like multi-color lasers, become viable, the capacity and speed become considerable. A stationary system with two sets of movers would only be required, up to a certain data-base size. More responsive voice coils could be employed.



   Figure 38 shows the bottom tray to pivot connection means 56 whereby the columns allow more overtravel 57 of the objective lens or allow a larger media surface to be placed into same footprint of a given housing. The pivot assembly is connected to the tray by columns placed in the remote corners of the drive so that the objective lens has more clearance for excursion.



   Figure 39 also shows a connection means 56 in a front view. Also shown is a balance weight 58 on top of the swivel for portable applications of the drive.



  The balance weight assures no change in force bias for the voice coil due to gravitational forces when the unit operates upside right, upside down, on its side, or combinations thereof. Dynamic balancing can also be achieved.



   Figure 40 is a top view of Figure 41.  



   Figure 41 shows a model employing a C-frame 59 tray structure and a one-sided voice coil and magnet assembly 60. A C-type bracket is used. The magnetic circuit assembly is only on one side, making it smaller and less expensive. Insertion of the voice coil is simplified. A one-sided voice coil and magnet assembly could also be utilized with a frame similar to that shown in Fig. 38 and 39. A right side 130 of the voice coil may be used as a balance weight or may be omitted.



   Figures 42 and 43 show another extreme, in principle. An air bearing, preferably a self-acting swivel 61, operates on a cylinder-like spherical media 62 with continual high-speed rotation. The X, Y and Z alignment means will rest against a stop means until rotational speed is attained before moving into the operating range.



   Figure 44 shows a pivot arrangement with a deep drawn integral C-structure. The pin is loaded to the retainer via a padded needle and a load spring.



  The dead stop is also shown.



   Figure 45 shows a similar arrangement. The pin portion has a slant to allow for a shallower construction. A flexible means loads the pin via a spring.



   Figure 46 is a side view of Figure 47.



   Figure 47 shows a pivot load spring 64 which exerts only minute lateral motion.



   Figure 48 shows voice coil or solenoid arrangement with a plunger 65 operating against a bias spring 66.



   While several embodiments in accordance with the present invention are shown, it is understood that the same is not limited thereto but is susceptible of numerous changes and modifications as known to those skilled in the art and the inventor therefore does not  wish to be limited to the details shown and described herein but intends to cover all such changes and modifications as are encompassed by the scope of the appended claims. For example, the voice coils could be made stationary with the magnets moving. Additionally, the (1-COS) element of the present   invention-could    be mounted on a head arm for a floppy or hard disk, coupled to a standard magnetic head A magnetic head with a megnetic media could be substituted for the optical head and optical media. A mirror tilt for the tracking and track offset and focusing means could be used.

   Holographic technologies could be used for the optics. 

Claims

WHAT IS CLAIMED IS:

1. An actuator for a record and/or read head comprising: a structure containing said head, said structure having a first, free end for placement adjacent a media; pivot means, coupled to a second end of said structure opposite said first end, for supporting said structure and allowing at least partial movement of said structure about said pivot means in at least two directions; and means for moving said structure about said pivot means.

2. The actuator of claim 1 wherein said head is an optical head.

3. The actuator of claim 2 wherein said optical head includes: an objective lens proximate said first end of said structure; and a photo emitter and photodetector mounted in said structure closer to a midpoint of said structure than to said first end.

4. The actuator of claim 3 further comprising: tracking and focus means, mounted to said structure between said pivot means and said objective lens for moving relative to said structure; and means for coupling said tracking and focus means to said objective lens.

5. The actuator of claim 4 wherein said means for coupling generates, for a given movement of said tracking and focus means, a smaller movement of said objective lens.

6. The actuator of claim 4 wherein said tracking and focus means comprises at least one voice coil, and said coupling means comprises at least one elongate member coupling said voice coil to said objective lens.

7. The actuator of claim 1 wherein said means for moving comprises: a coil coupled to said structure; and at least one magnet, fixed with respect to said coil for interacting with said coil to cause movement of said coil.

8. The actuator of claim 7 wherein said coil encircles said structure and is curved so that all points of said coil are equidistant from a pivot point of said pivot means, a projection of said coil onto a plane normal to an axis of said structure between said first and second ends being a parallelogram.

9. The actuator of claim 7 wherein said coil is mounted on only one side of said structure.

10. A media for storing data having an exposed concave surface with the shape of a portion of a sphere.

11. The apparatus of claim 10 wherein said media is contained in a planar card.

12. An actuator for an optical head comprising: an elongate, hollow arm containing said head, said arm having a first, free end; pivot means, coupled to a second end of said arm opposite said first end, for supporting said arm and allowing at least partial movement of said arm about said pivot means in at least two directions; a voice coil coupled to said arm proximate said pivot means, said coil encircling said arm and being curved so that all points of said coil are equidistant from a pivot point of said pivot means, a projection of said coil onto a plane normal to an axis of said arm between said first and second ends of said arm being a parallelogram; at least one magnet, fixed with respect to said coil for interacting with said coil to cause movement of said coil, said magnet being shaped to allow passage of said coil as said arm is moved;

; an objective lens of said optical head and on the proximate said first end of said structure; a photoemitter and photodetector of said optical head mounted in said arm between said pivot means and said first end; at least one focus and tracking voice coil mounted proximate a midpoint of said arm; means for coupling said focus and tracking voice coil to said objective lens; and a media for storing data having an exposed concave surface with the shape of a portion of a sphere on a proximate said first end of said arm, said sphere having a centerpoint at said pivot point.

13. The apparatus of claim 12 further comprising: means for deflecting a laser beam mounted inside said arm proximate a midpoint of said arm; and means for moving said deflecting means to track data on said media.

14. The apparatus of claim 12 further comprising a second arm coupled to said pivot means opposite said first arm.

15. The apparatus of claim 11 wherein a plurality of said media are contained in said planar card.

16. The media of claim 10 wherein said media includes at least two segmented surfaces.

17. An apparatus for moving a record and/or read head or portion of a head mounted on the end of an arm, comprising: means, mounted between said end of said arm and a pivot point of said arm, for moving relative' to said arm; and means for coupling said means for moving to said head or portion of a head, such that a given movement of said means for moving generates a smaller movement of said head or portion of a head.

18. The apparatus of claim 17 wherein said portion of a head is an objective lens of an optical head.