Patent Application
20060072381
The present invention relates to apparatuses and methods for determining and adjusting one or more performance parameters of a head suspension or head suspension assembly of the type generally used in dynamic storage devices such as magnetic disk drives. In particular, the present invention relates to apparatuses and methods that use a laser based technique to adjust a performance parameter.
Head suspensions are well known and commonly used within dynamic magnetic or optical information storage devices or drives with rigid disks. The head suspension is a component within the disk drive that positions a magnetic or optical read/write head over a desired location on the storage media. Head suspensions for use in rigid disk drives typically comprise a three-piece construction having a load beam, a flexure, and a baseplate. The load beam typically includes a proximal end for attachment to the baseplate, a rigid region extending toward a distal end, and a spring region between the rigid region and the base for providing a bias force. The flexure, located at the distal end of the load beam, has a pad or tongue to which a slider capable of supporting a read/write head can be mounted. Head suspensions are normally combined with an actuator arm or E-block to which the baseplate is mounted for positioning the head suspension, and thus the slider and read/write head, with respect to data tracks of the rigid disk.
The flexure permits pitch and roll motion of the slider and read/write head as they move over the data tracks of the disk. The flexure does this by providing a gimbal connection between the head slider and load beam. This type of gimbal connection can be provided in numerous ways such as by using a flexure that is formed separately from the load beam and then attached to the load beam or a flexure that is formed integrally with the load beam. According to one version of a three-piece head suspension construction, the flexure comprises a slider mounting tongue suspended by spring or gimbal arms. The slider is mounted to the tongue, thereby forming a head suspension assembly. The slider includes a read/write magnetic transducer or head provided on the slider and the slider is aerodynamically shaped to use the air bearing generated by a spinning disk to produce a lift force. During operation of such a disk drive, the gimbal arms permit the slider to pitch and roll about a load dimple or load point of the load beam, thereby allowing the slider to follow the plane of the disk surface.
In operation, a disk(s) of a disk drive rotates at high speeds, while a read/write head is positioned so that there is only a minimal air gap separation between the head and the disk surface. Providing a consistent air gap separation during operation of the disk drive is critical to assure accurate reading and storing of information on each disk. If the air gap is too large or if it varies during operation of the disk drive, critical information can be lost or misread by the head. Conversely, if the air gap is eliminated such that a read/write head can come into contact with an adjacent hard disk, permanent loss of data can occur along with damage to the head and disk that may be difficult or impossible to repair. In order to maintain the necessary air gap separation, it is thus important to properly adjust and maintain various parameters of each head suspension during their manufacture and assembly.
In relation to this, an important performance-related parameter of a head suspension is the orientation or attitude of the head slider as it flies over a disk surface. This orientation or attitude can be termed slider flying attitude and refers to the positional orientation of the head slider with respect to the surface of the disk when the head suspension is loaded, that is, under the influence of the balanced forces created by the spring force and the air bearing. When the head suspension is not actually flying over a spinning disk, this loaded state can be simulated. This can be done by applying a force in the same direction as the air bearing force at a point on the head suspension other than the head slider or, if the slider is not attached, a head slider bond pad where the head would be attached. This force is applied to lift the head slider to its loaded position or loaded state at fly height. The orientation or attitude of the head slider or slider bond pad under this simulated loaded state is referred to as its static attitude. Measuring static attitude can be easier than measuring slider flying attitude and static attitude can be correlated to slider flying attitude. As such, static attitude is often used as a performance parameter of a head suspension.
Because of the importance of correct slider flying attitude and the ability to correlate slider flying attitude to static attitude, various methods have been developed to obtain appropriate static attitude. Known adjust techniques cause a deformation or bending in a controlled manner of some portion of a head suspension to adjust static attitude. In one approach an apparatus that mechanically acts upon the load beam is used to manipulate, by twisting or bending, the load beam to adjust static attitude. In another approach, an apparatus that mechanically acts, in a similar manner, on a gimbal portion of a suspension is used. A more recently developed technique uses a laser to cause a controlled bend in some portion of a suspension to adjust static attitude. By controlling certain parameters of the laser radiation, a desired bend in the suspension can be achieved.
In a typical laser bending technique, a surface of the suspension is irradiated with a laser beam so that an area of the surface is quickly heated. If the material is only heated through a portion of its thickness, a temperature gradient between the front and back surfaces results. As cooling occurs, stresses form near the heated region and cause a permanent deformation in the suspension. This deformation can be used to adjust a performance parameter, such as static attitude, of a suspension.
One developed manner of irradiating a laser beam onto a suspension surface is to scan a laser beam across one or more surfaces of a suspension to adjust a performance parameter of the suspension. Scanning a beam along a predetermined path provides a temperature gradient between the front and back surfaces of the suspension along the scan path. As such, a permanent deformation can be introduced to the suspension along the scan path and a portion of the suspension can be deformed in a controlled manner to a greater extent as compared to heating an area of the suspension corresponding only to the spot size of the laser.
Known techniques for irradiating and scanning a laser beam across a surface of a suspension use a galvanometer based beam steering system to direct a laser beam along a desired path. High speed beam steering can be achieved by using mirrors mounted on computer controlled galvanometers that move the mirror(s) to direct the laser beam along the desired scan path. Such galvanometer based systems are known in the art and typically have the ability to steer a laser beam in two dimensions within a working field on a flat working surface. Because the beam is steered around within such a working field, these galvanometer based systems also use specially designed optics for focusing the beam. These focusing optics are known as F-Theta lenses and are designed to maintain the focus of a laser beam on a surface within a large working field. As such, the F-Theta lens is provided in a position stationary to the target working field and the beam is movable within the limits of the functional area of the F-Theta lens and thus within the target working field. The location of the focused spot on the working surface as focused by the F-Theta lens is proportional to the angle of the beam on the F-Theta lens. Thus, a longer focal length is required for such a lens to achieve a larger field size.
While such galvanometer based systems are effective for providing a laser beam that can be scanned along a predetermined path on a surface of a suspension for adjusting a performance parameter such as static attitude, several limitations exist. First, the working field of the focused beam is defined by the functional area of F-Theta lens. If a larger working field is desired, a lens having a larger functional focusing area must be used. Second, an F-Theta lens is designed to maintain the focus of a beam within predetermined limits of a predetermined plane such as the working field of a working surface. Thus, it is not possible to control the focus of the beam on the working surface with this type of beam steering system. For example, it may be desirable to over-focus or under-focus the beam in order to adjust the spot size of the beam. Third, the minimum spot that can be achieved for a laser beam focused by an F-Theta lens is larger than that which can be achieved with other focusing lenses.
The present invention provides apparatuses and methods for adjusting one or more performance parameters of a head suspension or head suspension assembly by using one or more laser adjust beams provided in a controlled directional manner. Generally, performance parameters such as static attitude, gram load, spring geometry, and load beam geometry, can be adjusted in accordance with the present invention.
In one aspect of the present invention an apparatus that scan a focused adjust beam across a surface of a suspension without using galvanometers and F-Theta lenses is provided. Generally, such an apparatus of the present invention includes a light source for providing an adjust beam and a focusing device for focusing the adjust beam. The adjust beam can be directed to the focusing lens along an optical path comprising any number of optical path defining elements. The apparatus is designed so that the focusing lens can be moved relative to the light source while maintaining the position of the adjust beam within the focusing lens. As such, the focusing lens and adjust beam can be moved relative to a surface of a suspension to scan the adjust beam across the surface of the suspension.
In another aspect of the present invention, the ability to deliver a laser adjust beam to different surfaces, such as oppositely facing surfaces, of a head suspension for adjusting a performance parameter in different adjust directions. For example, in one aspect of the present invention, an adjust beam can be delivered or directed to a surface of a predetermined portion of a head suspension along a first predetermined optical path to adjust a performance parameter in a first direction. The adjust beam can be delivered along a second predetermined optical path to another surface, such as an oppositely facing surface of the predetermined portion, to adjust the performance parameter in a second direction.
In another aspect, the present invention also provides adjust beams that have a small spot size as compared to those previously used for adjustment of performance parameters such as static attitude. As such, the present invention provides apparatuses and methods that facilitate the use of such small spot sizes to adjust such performance parameters. For a given material thickness and the same laser power density, a smaller spot size provides finer control over the magnitude of the stresses and increased adjust resolution. Thus, a small spot size, in accordance with the present invention, can provide increased precision and accuracy for adjusting performance parameters.
Accordingly, in one aspect of the present invention, a fiber laser and a gradient index focusing lens can be used to provide an adjust beam having a spot size that is significantly smaller than those previously used for laser adjust of performance parameters such as static attitude, for example. Moreover, in another aspect of the present invention, an apparatus can be provided that includes the ability to translate an adjust beam across a surface portion of a head suspension in order to adjust a performance parameter.
In another preferred aspect of the present invention, a method for directionally adjusting a performance parameter of a head suspension by impinging an adjust beam on first and second surfaces of the head suspension is provided. This method preferably comprises the steps of providing a light source, directing an adjust beam of the light source to impinge on a first surface of a head suspension by movably positioning an optical path defining element of a first optical path relative to the adjust beam. An adjust beam can be used to controllably heat a predetermined region of the head suspension for adjusting a performance parameter of the head suspension. By impinging an adjust beam on the first surface of the head suspension, the performance parameter of the head suspension can be adjusted in a first direction. In a similar manner, an adjust beam can be impinged on a second surface of the head suspension. By impinging an adjust beam on the second surface of the head suspension, the performance parameter of the head suspension can be adjusted in a second direction. That way, cooperative adjustment by plural beams in either the first or second directions can be used to adjust a performance parameter.
In yet another aspect of the present invention, a method for adjusting a performance parameter of a head suspension with a laser adjust beam that has a small spot size is provided. The method includes impinging a laser adjust beam on a surface of a portion of the head suspension wherein the laser adjust beam has a spot size that is less than the thickness of the portion of the head suspension. The laser adjust beam controllably heats a predetermined region of the surface of the portion of the head suspension with the laser adjust beam for adjusting a performance parameter of the head suspension.
These and other features, aspects, and advantages of the present invention will become better understood with regard to the following description, appended claims, and accompanying drawings where:
Dynamic data storage devices, such as magnetic or optical storage drives are well known in the industry and typically include rigid or floppy disks. Rigid magnetic drives, for example, use a rigid disk coated with a magnetizable medium for storage of digital information in a plurality of circular, concentric data tracks. The disk is usually mounted on a motorized spindle which spins the disk and causes the top and/or bottom surfaces of the disk to pass under respective read/write heads. A typical head includes a hydrodynamically designed air bearing slider and a transducer for writing information to and/or reading information from the disk surface. An actuator mechanism moves the heads from track to track across the surfaces of the disk under control of electronic circuitry. The actuator mechanism typically includes an arm, or e-block and each arm is then connected with one or more head suspension assemblies.
Head suspension assemblies, also sometimes known as head gimbal assemblies, are commonly used in rigid disk drives to support the heads in close proximity to the rotating disk surfaces. Typically, such head suspension assemblies provide a preload bias that forces the read/write heads toward a disk surfaces to counteract an aerodynamic lift force that acts in an opposite direction as the head flies on a generated air bearing above the rotating disk surface. The force of such bias is often referred to as the gram load and can be adjusted by controlling the shape and geometry of a spring section of the head suspension.
One such exemplary head suspension assembly 10 is illustrated in
When incorporated into a disk drive, the mounting region 18 of the load beam 16 can be mounted to an actuator or positioning arm (not shown) which supports the head suspension assembly 10 over a rotating disk. A baseplate 22, which usually includes a mounting hole 24, is typically welded to the mounting region 18 to increase the rigidity of the mounting region and to provide a mechanism for securely mounting the head suspension assembly 10 to the positioning arm.
The load beam 16 is an elongated and often generally triangularly-shaped member, which includes a spring section 26 adjacent to the mounting region 28 for creating the preload bias, and a rigid section 28, which extends from the spring section 26. Typically, the rigid section 18 includes stiffening features 30, such as rails, that extend along at least a portion of the sides of the rigid section 28 for transferring the preload bias to the flexure 20 and thus slider 12.
The spring section 26 of the head suspension assembly 10 shown in
The head slider 12 contains a head (not shown) for reading and/or writing data, has an air bearing surface 13, and is typically bonded to the flexure 20 by adhesive or the like. The air bearing surface is aerodynamically designed to ride on an air bearing created above a spinning disk so that the head can fly with respect to the spinning disk. The spring force thus counteracts to balance and define the “flying height” of the head slider as described in more detail below.
In
In
As can be seen in
Referring to
The preload bias and the hydrodynamic lifting force reach equilibrium based upon the hydrodynamic properties of the slider 12 and the speed of rotation of the disk 44. The preload bias is transferred from the load beam 16 to the slider 12 through the load point dimple 42. Accordingly, the load point dimple 42 provides a point about which the slider 12 can pitch and roll and it limits vertical displacement of the slider 12 and flexure 20 in a direction away from the disk surface. The rotation of the disk 44 causes the slider 12 to be positioned a distance 46 from the surface of the disk 44. The distance 46 is referred to as the slider “flying height” and represents the position that the slider 12 occupies when the disk 44 is rotating during normal operation. It is desirable to maintain the flying height 46 within a limited range in order to ensure high quality of the data read from or written to the disk 44.
Static attitude includes a pitch component and a roll component. In
Shown in
While static attitude and gram load are considered to be critical performance parameters, another critical performance parameter of a suspension relates to its resonance characteristics. In order for the head slider to be accurately positioned with respect to a desired track on the magnetic disk, the head suspension should be capable of precisely translating or transferring the motion of the positioning actuator arm to the slider. An inherent property of moving mechanical systems, however, is their tendency to bend and twist in a number of different modes when subject to movements or vibrations at certain rates known as resonant frequencies. At resonant frequencies that may be experienced during disk drive usage, the movement of a distal tip of the head suspension assembly, or its gain, is at is maximum, so such gain is preferably minimized by the construction of the head suspension assembly. Any bending or twisting of a head suspension can cause the position of the head slider to deviate from its intended position with respect to the desired track, particularly at such resonant frequencies. Because the disks and head suspension assemblies are driven at high rates of speed in high performance disk drives, the resonant frequencies of a head suspension should be as high as possible. Resonance characteristics are usually controlled by precision construction, design and manufacture of the load beam. Accordingly, any changes or deformation to a head suspension may adversely affect the resonant characteristics of the head suspension assembly. In order to control such resonance characteristics it may be necessary to adjust the shape and/or geometry of certain portions of the head suspension assembly such as the load beam and spring region, for example.
With reference to
The apparatus 100 can be used to measure and adjust either or both roll static attitude and pitch static attitude of a head suspension or head suspension assembly during manufacture or assembly of such suspensions, for example. As shown, the apparatus 100 generally includes a tool head 102 and an autocollimator 106 for measuring a surface orientation such as static attitude and may include any other measurement and/or characterization devices for measuring any desired performance parameters. The tool head 102 preferably includes a working region 104 that can receive a component to be measured and/or adjusted. For example, an exemplary component 108 is schematically shown positioned in the working region 104 of the tool head 102 as provided by a carrier strip 111 supported by a workpiece holder 109 that is schematically shown and described in more detail below.
In accordance with preferred uses of the present invention, the component 108 is a head suspension or a head suspension assembly such as the exemplary head suspension assembly 10 described above with respect to
As illustrated, the apparatus 100 includes a baseplate 110. The tool head 102 and the autocollimator 106 are preferably operatively positioned with respect to the baseplate 110. The autocollimator 106 is preferably supported and positioned with respect to the baseplate 110 by an arm 112 so that the autocollimator 106 is positioned in a fixed position with respect to the baseplate 110. As shown in
Preferably, the autocollimator 106 comprises a measurement device that is capable of measuring an angular orientation such as the static attitude of a surface of the component 108. Generally, the autocollimator 106 provides a light beam that can be used to determine the angular orientation of such a surface with respect to a predetermined frame of reference. The light beam is directed to impinge upon the surface so that a detector can sense a reflected portion of the light beam. Information such as the position of the reflected beam on the detector can then be used to determine the angular orientation of the surface, which can be used to determine static attitude of the surface. Exemplary autocollimators that can be used in accordance with the present invention are the subject of currently co-pending and co-assigned U.S. patent application Ser. No. 10/138,728, filed May 3, 2002, and entitled “Static Attitude Determination and Adjust of Head Suspension Components,” the entire disclosure of which is incorporated fully within this application by reference for all purposes. Although autocollimator based devices are preferred, any measurement device, probe, or instrument whether utilizing optical, electrical, or mechanical means and that is capable of determining the static attitude or angular orientation of a surface in accordance with the present invention can be used.
The tool head 102 can be used to deliver a laser adjust beam to a surface of the component 108 for adjusting the static attitude of the component 108 as based on a measured static attitude and a predetermined desired static attitude. However, it is noted that static attitude can be adjusted as based on any information, however attained, and/or static attitude can be adjusted without first measuring static attitude with any device such as the autocollimator 106. Moreover, static attitude can be measured in an unloaded or loaded state of a head suspension or head suspension assembly as described above with respect to
With respect to the tool head 102, the apparatus 100 is preferably designed so that the tool head 102 is movably positionable with respect to the baseplate 110 in one or more directions. As such, the working region 104 of the tool head 102 can be positioned and moved with respect to the component 108 for providing an adjust beam to a surface of the component 108 as described in more detail below.
In one aspect of the present invention, the ability to scan an adjust beam along a predetermined path and controllably focus the beam on a surface of the component 108 by moving the tool head 102 is provided. Thus, the apparatus 100 preferably includes movable stages 118 and 120 and movable stage 128 (see
Such moveable stages typically include a first portion that is movably provided with respect to a second portion of the moveable stage such as by using bearings, shafts, lead screws, and the like as are conventionally known. Generally, the first and second portions are drivable with respect to each other such as by using a motor or the like. Such driving of the movable stage can be controlled by using a control system as mentioned below. The first portion of such a moveable stage can be attached to the tool head 102 and the second portion of the moveable stage can be attached to the baseplate 110 so that the tool head 102 and the baseplate 110 can be controllably moved with respect to each other by driving one portion of the moveable stage relative to the other.
As shown, the movable stage 118 is mounted to the baseplate 110 by an adapter plate 122 and the movable stage 120 is mounted to the movable stage 118 by an adapter plate 124. The tool head 102 is preferably mounted to the movable stage 120, as shown. The adapter plates 122 and 124 make it easier to assemble the moveable stages 118 and 120 with respect to each other and with respect to the tool head 102 and the baseplate 110. However, the moveable stage 118 could be mounted directly to the baseplate 110 without using the adapter plate 122, if desired. Similarly, the movable stage 120 could be mounted directly to the moveable stage 118 without using the adapter plate 124, if desired. Preferably, the movable stage 118 is capable of providing motion to the tool head 102 in the y-axis. In any case, any type of mechanism or device can be used to provide any desired relative motion between the tool head 102 and a component, such as component 108, positioned with respect to the working region 104 of the tool head 102 including moving the component 108. Also, the apparatus 100 preferably includes a control system (not shown) for controlling the motion of the movable stages 118, 120, and 128 (controlling the driving of motors on movable stages, for example). The control system can be used to control other aspects of the apparatus 100 such as those related to control aspects of measurement and adjust processes as described below.
Because the autocollimator 106 of the exemplary apparatus 100 is preferably in a fixed position with respect to the baseplate 110, the workpiece holder 109 can be capable of positioning the component 108 in a measurement position with respect to the autocollimator 106. However, as noted above, the autocollimator 106 can be movable in order to perform a measurement on the component 108. A measurement position generally refers to a position where a desired surface of the component 108 is positioned with respect to the autocollimator 106 so that the autocollimator 106 can determine the angular or planar orientation of such surface. For example, a measurement position may be the location of the focal point of a measurement beam of the autocollimator 106.
After a measurement has been made with the autocollimator 106, the movable stages 118, 120, and 128 are preferably used to position the working region 104 of the tool head 102 with respect to the component 108 (while still positioned in the measurement position) so that a laser adjust beam can be delivered to the component 108 for adjusting a performance parameter such as static attitude as described in greater detail below.
The component 108 can be provided to the working region 104 of the tool head 102 in any manner. Preferably, the apparatus 100 is integrated into a manufacturing line or system. As such, the workpiece holder 109 can comprise any mechanisms or devices that are capable of controllably positioning the component 108 in a measurement position with respect to the autocollimator 106. For example, the workpiece holder 109 may include clamping and/or fixturing devices. Preferably, in the exemplary apparatus 100, the autocollimator 106 remains stationary, as shown, and the component 108 is moved into the measurement position with respect to the autocollimator 106.
For example, the apparatus 100 can be used as a station of a head suspension assembly manufacturing system. In some systems currently in use for manufacturing head suspensions, suspensions are provided on a carrier strip (such as the carrier strip 111 illustrated in
With reference to
As can best be seen in
With reference to
Also, with respect to the mirror 139 the mounting plate 126 preferably includes a bore 162 that can slidingly receive a post 164. As shown, the post 164 preferably includes a mounting surface 166. Preferably, a surface 168 of the mirror 139 can be attached to the mounting surface 166 of the post 164 as described above, for example. Like the post 144, the post 164 can preferably rotate within the bore 162 and translate with respect to the bore 162 (along the y-axis) in order to adjust the orientation of the mirror 139 with respect to the mounting plate 126. Also a set screw (not shown) is preferably provided in a tapped hole 180 for the post 164 within the bore 162.
Further referring to
Referring to
Referring to
Referring to
Referring to
As described above with respect to
The optical system 105 shown schematically in
As mentioned above, the optical path 220 can be selected by impinging the beam 232 from the laser 132 on the mirror 134. This can be accomplished by moving the movable stage 128 so that the objective mount 130 positions the mirror 134 with respect to the beam 232. The optical path 222 can be selected in a similar manner by impinging the beam 232 from the laser 132 on the mirror 138. Accordingly, the movable stage 128 can be used to move the objective mount 130 so that the mirror 138 is positioned with respect to the beam 232. Alternatively, it is contemplated that the laser 132 could be moved in order to selectively impinge the beam 232 on either of the mirror 134 or the mirror 138. It is further contemplated that multiple lasers could be used to selectively deliver an individual beam to the mirrors 134 and 138 or that the beam 232 could be split into multiple beams that could be selectively directed to the mirrors 134 and 138. In any case, the optical system 105 is preferably designed so that a laser adjust beam, for adjusting static attitude, can be delivered to one or more surfaces of a head suspension or head suspension assembly, either independently (by selecting a particular surface, or example) or simultaneously (selecting plural surfaces) for adjusting one or more performance parameters.
Preferably, in accordance with the present invention the optical system 105 is designed so that the ratio of the diameter of the spot size of an adjust beam (beam 226 and/or beam 229, for example) to the thickness of the material being adjusted is less than one. More preferably, the ratio of the diameter of spot size of an adjust beam to the thickness of the material being adjusted is less than 0.7. In other words, the diameter of spot size of adjust beam is preferably less than the thickness of the material being adjusted and more preferably less than 70 percent of the thickness of the material being adjusted. As an example, for a head suspension or head suspension assembly that has a gimbal portion that has a thickness of 10 microns, a preferred spot size diameter would be less than 10 microns and more preferably about 7 microns.
A spot size diameter that is less than the thickness of the material being adjusted provides significant advantages for adjusting static attitude as provided by the present invention. Bending occurs when thermal stresses are created in the material to be bent. Such thermal stresses can be created by heating an area of one side of the material so that a temperature gradient is created between oppositely facing surfaces of the material with respect to the heated area (across a material thickness, for example). In other words, a temperature gradient is provided through the thickness of the material by increasing the temperature of the material through a portion of its thickness. Where a laser beam is used to provide such heating, the thermal gradient is provided in the region that corresponds with the spot size diameter of the laser beam. As the material cools, thermal stresses are created because of differential thermal contraction of the material through its thickness. These stresses cause the material to bend, which bending can be controlled by controlling the application of heat to the material. Accordingly, by heating a smaller area of the material a greater adjust resolution can being provided. Moreover, increased adjust resolution can provide increased repeatability for adjusting static attitude. Combined with the ability to selectively direct an adjust beam to oppositely facing surfaces of a head suspension or a head suspension assembly, the present invention provides techniques for adjusting static attitude with increased resolution and with greater control especially in that the static attitude can be adjusted in plural directions.
In order to provide such spot sizes, the laser 132 preferably comprises a laser that is capable of being focused to have a spot size diameter in accordance with the present invention. As mentioned above, one such laser that can be used is a fiber laser. For example, ytterbium based fiber lasers as commercially available may be used. Also, gradient index focusing lenses are preferably used. However, any lenses that can provide spot sizes in accordance with the present invention can be used. For example, conventional lenses with focal lengths less than about 50 mm can be used to achieve such spot sizes.
The apparatus 100 described above can therefore be used to adjust a performance parameter such as static attitude of a head suspension or a head suspension assembly with greater control, accuracy, resolution, and repeatability than that previously known in the prior art. As described below with respect to one exemplary method of adjusting a performance parameter such as static attitude, the apparatus 100 provides many functional features and parameters that can be utilized for adjusting such performance parameters all of which may be controlled by a control system.
Preferably, a component such as the component 108 shown in
Preferably, when the component 108 is positioned in a measurement position with respect to the autocollimator 106, the tool head 102 is retracted in the y-axis so that the tool head 102 does not block a line of site between the autocollimator and the component 108. It is noted, however, that the autocollimator 106 can be positioned or movable in any manner so that the autocollimator 106 can measure the static attitude of the component 108 in accordance with the invention. It is contemplated, however, that the static attitude of the component 108 does not need to be measured and the component 108 can be adjusted in any desired manner as based on information or parameters (empirical, theoretical, etc.) related to a desired bending or adjust or desired static attitude.
After the autocollimator 106 has measured the static attitude of the component 108, the tool head 102 is preferably moved in the y-axis so that the component 108 is positioned in the working region 104 of the tool head 102. The tool head 102 can then be used to deliver an adjust beam to a surface of the component 108 for adjusting the static attitude of the component 108 by causing a predetermined portion of the component to bend as described above. For example, the object mount 130 can be moved into a position to select the optical path 220 for delivering the adjust beam 225 to the surface 224 of the component 108. As such, the static attitude can be adjusted in a first direction. If needed, the static attitude can be adjusted in a second direction. For example, the object mount 130 can be moved into a position to select the optical path 222 for delivering the adjust beam 229 to the surface 228 of the component 108.
Preferably, in order to cause a desired bend for adjusting static attitude, an adjust beam is scanned or traced across a surface of the component 108. Preferably, an electrical control system is used for controlling movements of the apparatus 100. The apparatus 100 therefore provides the ability to scan an adjust beam in any desired direction. For example, the movable stage 118 can be used to scan an adjust beam with respect to a surface of the component 108 in the y-axis. An adjust beam can also be scanned in the x-axis by moving the object mount 130 with the movable stage 128. For example, the mirror 134 can be translated in the x-axis with respect to the beam 232 thereby causing the adjust beam to also move in the x-axis. The same approach can be used with respect to the mirror 138 and adjust beam.
Typically, an adjust beam is scanned linearly in one or both of the x-axis and y-axis. However, it is contemplated that an adjust beam can be scanned in any desired direction and can change direction in any desired manner. In other words, an adjust beam does not need to be scanned linearly in order to adjust static attitude in accordance with the invention. An adjust beam can be scanned in a back and forth or zigzag pattern or in a curving manner for providing any desired bending effect for adjusting static attitude. An electrical control system can be used to control such scanning motion as well as for controlling aspects of the adjust beam such as an on or off state of the adjust beam, for example.
An adjust beam can be scanned in a continuous manner or may be pulsed depending on the desired bending effect that is desired. Also, other parameters can be used in order to control or provide a desired bending effect. Parameters such as the power density of the adjust beam as well as the scan rate of the adjust beam can be used in order to control the amount of energy or heat that is provided to the component 108. Control over any of these parameters can be integrated within the control functionality of a control system.
The apparatus 100 also provides the ability to focus an adjust beam with respect to a surface of the component 108. Preferably, the movable stage 120 is used to position an adjust beam on a surface of the component 108 so that a focal point of the adjust beam, as focused by a focusing lens, is focused on the desired surface. For example, the movable stage 120 (as controlled by a control system, for example) can be used to move the focal point of the adjust beam 225 in the z-axis so that the focal point is focused on the surface 224 of the component 108. Likewise, the focal point of the adjust beam 229 can be similarly focused on the surface 228 of the component 108. It is also contemplated that an adjust beam can be positioned with respect to a surface of the component 108 so that the adjust beam is out of focus with the surface. Such a technique can be used to increase or decrease the diameter of the spot size of an adjust beam in order to controllably provide a desired bending effect for adjusting static attitude.
In accordance with the present invention, the above-described bending is preferably correlated to a determination or measurement of the static attitude (or other performance parameter). That is, a desired or target static attitude may be determined prior to making an adjustment. As described above, determination of the static attitude or of the planar orientation of a surface can be accomplished by utilizing the preferred autocollimator 106. For example, the planar orientation of a slider mounting tongue or a slider to be adjusted may be determined and the above-described adjustment may be performed and the planar orientation remeasured until a desired planar orientation is accomplished. Additionally, the planar orientation of a reference surface may also preferably be determined and then utilized to accomplish a desired adjustment to the static attitude of the slider mounting tongue or the slider. That is, the planar orientation of a surface such as a surface of a load beam, flexure, gimbal arm, or any other surface may be used as a reference surface. In certain aspects of the present invention, a predictable relationship between the static attitude of head suspensions or head suspension assemblies in an unloaded state and a loaded state may be determined by measuring both the static attitude and the planar orientation of a reference surface such as a surface of a load beam. Such a relationship may also be based on theoretical and/or empirical data.
The present invention has now been described with reference to several embodiments thereof. The entire disclosure of any patent or patent application identified herein is hereby incorporated by reference. The foregoing detailed description and examples have been given for clarity of understanding only. No unnecessary limitations are to be understood therefrom. It will be apparent to those skilled in the art that many changes can be made in the embodiments described without departing from the scope of the invention. Thus, the scope of the present invention should not be limited to the structures described herein, but only by the structures described by the language of the claims and the equivalents of those structures.
