Abstract:
The slider tester is capable of solely testing a slider and securely selecting good sliders so as to reduce wasteful costs. The slider tester, which tests reading and writing functions of a slider for reading data from and writing data on a recording medium, includes a testing device for testing the functions of the slider, and a setting plate holding the slider and electrically connecting the slider to the testing device. The setting plate separates the slider a prescribed distance from the recording medium during the test so as to read data from and write data on the recording medium, wherein the slider can be independently attached to and detached from the setting plate.

Description:
BACKGROUND OF THE INVENTION 
   The present invention relates to a slider tester, which tests reading and writing functions of a slider (a magnetic head) for reading data from and writing data on a recording medium. 
   The slider for reading data from and writing data on a recording medium, e.g., a magnetic disk, is tested, then it is actually assembled in, for example, a magnetic disk drive unit. In the test, the recording medium is rotated, and floating characteristics and recording and writing functions of the slider are checked. In the conventional function test of the slider, a slider unit including the slider and a suspension, on which the slider is mounted, is assembled, then the slider unit is set in the slider tester so as to execute the function test. In the conventional slider tester, the recording medium is rotated so as to float the magnetic head therefrom, and a floating distance and the reading and writing functions of the slider are checked, so that the slider is judged if it is a good slider or a bad slider. The bad slider is scrapped together with the suspension. 
   Note that, in the present specification, the word “float” means the action of the slider moving away from a surface of the recording medium. Namely, the slider may be moved not only upwards with respect to the surface of the recording medium but also downwards and sidewards. 
   If the rate of producing bad sliders is high, many sliders are scrapped together with suspensions, so wasteful costs, e.g., costs of manufacturing sliders and suspensions and assembling slider units, are compounded. In the magnetic head for accessing a recording medium having a large capacity, the suspension has high functions and additional values. Therefore, the cost of manufacturing the suspension cannot be ignored. Further, the functions of the slider must be higher with increasing th capacity of the recording medium; high manufacturing technology is required, but yield of manufacturing sliders must be lower. Namely, the number of scrapped slider units and the wasteful costs are increased. 
   To solve this disadvantage, a method of testing the slider, in which the slider alone is tested before assembling the slider unit and only the good slider is mounted onto the suspension, is proposed. In the case of testing the, slider only, a recording medium is rotated and the slider is floated therefrom so as to check the floating distance and the reading and writing functions as well as the slider mounted on the suspension. 
   A lifting force of air, which is generated by rotating the recording medium, lifts or floats the slider from the recording medium; the suspension applies a pressing force, which is balanced with the lifting force, to the slider. Therefore, the floating distance of several tens nm from the recording medium can be maintained. 
   Namely, the slider tester must support the slider without obstructing the lifting force and apply the fixed pressing force to the slider. The slider must be easily set into and taken out from the slider tester before and after the test. The slider in a floating state must be electrically connected to a testing device. 
   SUMMARY OF THE INVENTION 
   An object of the present invention is to provide a slider tester, which is capable of solely testing a slider under conditions as well as a slider mounted on a suspension and securely selecting good sliders so as to reduce wasteful costs. 
   To achieve the object, the present invention has the following structures. 
   Namely, the slider tester, which tests reading and writing functions of a slider for reading data from and writing data on a recording medium, comprises: a testing device for testing the functions of the slider; and a setting plate holding the slider and electrically connecting the slider to the testing device, the setting plate separating the slider a prescribed distance from the recording medium during the test so as to read data from and write data on the recording medium, wherein the slider can be independently attached to and detached from the setting plate. 
   With this structure, the slider can be correctly solely tested under the conditions as well as a slider mounted on a suspension, and the results of the test can be correctly judged. Since the slider can be solely tested, the costs of manufacturing the suspension and assembling a slider unit can be omitted so that manufacturing cost can be effectively reduced. Further, by reducing the wasteful costs, the manufacturing cost of the slider for accessing a recording medium having high recording density can be reduced. 
   In the slider tester, the setting plate may comprise: a gimbal made of a metal plate having a slit, the gimbal moving the slider to and away from the recording medium and inclining the slider in optional directions; a fixed base section, to which the slider is detachably attached, being attached to the gimbal; and a press pin biasing the fixed base section toward the recording medium. With this structure, the slider can be inclined in the optional directions according to a suspension on which the slider will be mounted, and a pressing force can be applied to the slider while the slider is floated. 
   In the slider tester, the setting plate may comprise: a gimbal made of an elastic metal plate having a slit, the gimbal biasing the slider with a fixed elastic force and inclining the slider in optional directions; and a fixed base section, to which the slider is detachably attached, being attached to the gimbal. With this structure, the function of he suspension can be gained without using the press pin, so that a structure of the setting plate can be simplified. 
   In the slider tester, a contact part of one of the fixed base section and the press pin may be formed into a smooth spherical shape. With this structure, the gimbal can be moved freely, and the pressing force can be stably applied without reference to a posture of the gimbal. 
   In the slider tester, the setting plate may be attached to an arm section, and the arm section may be detachably attached to a mounting base fixed to a body proper of the slider tester. With this structure, the slider can be easily attached and detached, therefore a mechanism for attaching and detaching the slider can be more freely designed. 
   In the slider tester, the setting plate may be attached to an arm section, the arm section may be detachably attached to an arm plate, and the arm plate having the press pin may be detachably attached to a mounting base fixed to a body proper of he slider tester. By providing the press pin in the arm plate, a floating structure of the setting plate can be simplified. Especially, in the case of having a plurality of arm sections so as to test many sliders, the cost of manufacturing the setting plate and the arm sections an be reduced. 
   The slider tester may further comprise a height adjusting mechanism for adjusting the height of the mounting base and/or a direction adjusting mechanism for adjusting a direction of a surface of the mounting base. With this structure, the degree of parallel and a distance between the slider and the recording medium can be easily adjusted. 
   The slider tester may further comprise: a position adjusting mechanism for adjusting a position of the arm section; a detecting section for detecting a position of the slider set on the setting plate; and a control section feeding back a detection result of the detecting section so as to correctly position the slider. With this structure, the degree of parallel and the distance between the slider and the recording medium can be automatically adjusted even if they are varied, so that highly precise test can be executed. 
   In the slider tester, cable patterns, which electrically connect the slider held on the fixed base section to the testing device, may be provided on the gimbal. With this structure, the thin and fine cable patterns can be formed. If toughness improved by the cable patterns is previously considered when toughness of the gimbal is designed, an optimum shape of the gimbal can be designed. 
   In the slider tester, the fixed base section may include: a contact block, on which a face of the slider including electric terminals is pressed so as to electrically connect the slider to the testing device; and a clamp spring elastically clamping the slider with the contact block. With this structure, the slider can be attached and detached in a limited space. 
   In the slider tester, an anisotropic electric conductive sheet may be adhered on the face of the contact block including the terminals. With this structure, the slider can be stably electrically connected to the contact block even if the slider is inclinedly set. 
   In the slider tester, the clamp spring may comprise: a fixed art being fixed to the fixed base section; a pressing part for pressing the slider toward the contact block, the pressing part being extended from the fixed part and including a free end; and a U-shaped bent part connecting the fixed part with the pressing part. With this structure, the clamp spring can be small-sized, the clamp spring can be moved to sufficiently attach and detach the slider, and durability of the clamp spring can be improved. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
     Embodiments of the present invention will now be described by way of examples and with reference to the accompanying drawings, in which: 
       FIG. 1  is a schematic view of a slider tester of an embodiment of the present invention; 
       FIG. 2  is an explanation view showing a setting plate supporting a slider; 
       FIGS. 3A and 3B  are plan views of a gimbal having slits; 
       FIG. 4  is a perspective view of the gimbal, on which cable patterns are formed; 
       FIG. 5  is a plan view of the gimbal, on which the cable patterns are formed; 
       FIGS. 6A and 6B  are explanation views in which the slider contacts terminals with anisotropic electric conductive sheet; 
       FIG. 7  is a perspective view of a fixed base section on which the slider is mounted; 
       FIGS. 8A and 8B  are explanation views of a clamp spring; 
       FIGS. 9A and 9B  are explanation views of a press mechanism; 
       FIG. 10  is a schematic view of the setting plate of another example; 
       FIGS. 11A and 11B  are explanation views of an arm section which is detachably attached to a mounting base; 
       FIG. 12  is an explanation view of the arm section which is detachably attached to an arm plate; 
       FIG. 13  is an explanation view of mechanisms for adjusting height and direction of the mounting base; and 
       FIG. 14  is an explanation view of a mechanism for automatically adjusting direction of the slider. 
   

   DETAILED DESCRIPTION OF THE EMBODIMENTS 
   Preferred embodiments of the present invention will now be described in detail with reference to the accompanying drawings. 
     FIG. 1  is a schematic view of a slider tester of the present embodiment. A body proper  10  of the slider tester includes: a driving section for rotating a recording medium  12  as well as an actual disk drive unit; a travel control section for moving the recording medium  12  toward test positions, at each of which the slider  14  is set; and a testing device, which tests reading and writing functions of each slider  14  for reading data from and writing data on the recording medium  12 . 
   Setting sections, to each of which the slider  14  to be tested is set, are provided to each comer of an upper face of the body proper  10 . The recording medium  12 , e.g., a magnetic disk, is supported by a spindle  13 , which is provided between the setting sections located on a front side and those located on a rear side with prescribed separations. The spindle  13  can be moved in a direction D 1  together with the recording medium  12 . Namely, two sliders  14  can be tested when the recording medium  12  is located at a right end of a stroke or a left end thereof. 
   Each setting section includes: a setting plate  20  supporting the slider  14 ; an arm section  22  supporting the setting plate  20 ; and a mounting base  24  supporting the arm section  22 . The mounting base  24  is fixed to a setting table  10   a . A pair of the arm sections  22 , which are located on the right side or the left side, are extended in the opposite directions from the mounting bases  24  so as to flow air in the same direction with respect to the sliders  14  to be tested. 
   The recording medium  12  is supported in a horizontal plan by the spindle  13 . As described above, the spindle  13  is provided between the setting sections located on the front side and those located on the rear side with prescribed separations, and it can be moved in the direction D 1  together with the recording medium  12 . By moving th recording medium  12  supported by the spindle  13  in the direction D 1 , all of the sliders  14  an be tested. Each slider  14  can be solely attached to and detached from the setting plate  20 . By attaching the sliders  14  to the setting plates  20  in order, the sliders  14  can be solely tested. 
   In  FIG. 2 , the slider  14  is set on the setting plate  20 . 
   The setting plate  20  includes: a gimbal  30  supporting the slider  14  in a state of floating from a surface of the recording medium  12 ; a fixed base section  40  detachably holding the slider  14 ; and a press mechanism  50  pressing and supporting the fixed base section  40 . Note that, in the present embodiment, the gimbal  30  supports the slider  14  under the recording medium  12  as the floating state. 
   The gimbal  30 , the fixed base section  40  and the press mechanism  50  will be explained in order. 
   (The Gimbal) 
   The gimbal  30  supports the slider  14 , which has been supported by the fixed base section  40 , and allows the slider  14  to incline in optional directions, e.g., a pitching direction and a rolling direction. The gimbal  30  is made of a thin metal plate, and it has arc-shaped slits  32  so as to allows the slider  14  to incline in optional directions. An outer edge of the gimbal  30  is adhered on an upper face of the setting plate  20 . There is formed a space, in which the fixed base  40 , etc. are provided and the fixed base section  40  can be inclined, under the gimbal  30 . Examples of the slits  32  of the gimbal  30  are shown in plan views of  FIGS. 3A and 3B . In each example, a setting section  34 , to which the slider  14  is set, is provided at a center of the gimbal  30 , and an inner slit(s)  32   a  and an outer slit(s)  32   b  are coaxially formed with respect to a center of the setting section  34 . 
   In  FIG. 3A , a pair of the inner slits  32   a  and a pair of the outer slits  32   b  are formed into half-arc shapes. Inner connecting sections  35   a , which are symmetrically arranged with respect to the setting section  34 , and outer connecting sections  35   b , which are also symmetrically arranged with respect to the setting section  34 , are arranged with angular separations of 90 degrees. By crossing a line L 1  connecting the inner connecting sections  32   a  and a line L 2  connecting the outer connecting sections  32   b  at the right angle, the setting section  34  can be supported and inclined in optional directions. 
   In  FIG. 3B , the arc-shaped inner slit  32   a  and the arc-shaped outer slit  32   b  nearly enclose the setting section  34 . The setting section  34  is supported by one inner connecting section  35   a  and one outer connecting section  35   b . The connecting sections  35   a  and  35   b  are symmetrically arranged with respect to the setting section  34 , so that the setting section  34  can be supported and inclined in optional directions. 
   Cable patterns are formed in the gimbal  30 . The cable pattern electrically connects the slider  14  to a testing device  80 , which is provided in the body proper  10 . 
     FIG. 4  is a perspective view of the gimbal  30  including the cable patterns  36 . The cable patterns  36  are extended to terminals  38  via the inner connecting sections  35   a , a rib  37  and the outer connecting section  35   b . An insulating layer is formed on a surface of the gimbal  30 , then an electric conductive film is formed on the conductive film so as to form the cable patterns  36  running through the rib  37 , etc. Shapes of the cable patterns  36  may be optionally designed. 
   The slider  14  to be tested is set on the fixed base section  40  located at the center of the setting section  34 . In  FIGS. 4 and 5 , a contact block  42  is provided in the gimbal  30 . The contact block  42  electrically connects the cable patterns  36  to electrodes of the slider  14  when the slider  14  is set on the fixed base section  40 . There are provided contact terminals in an inner face of the contact block  42 . The contact terminals correspond to the electrodes of the slider  14 , which are formed in a side face of the slider  14 . By electrically connecting the cable patterns  36  to the contact terminals, the slider  14  can be electrically connected to the cable patterns  36  when the slider  14  is set on the fixed base section  40 . 
   Another process of forming the contact terminals in th inner face of the contact block  42  will be explained. Firstly, the contact terminals are formed at ends of the cable patterns  36  by patterning. The contact terminals are formed at positions corresponding to the contact block  42  on the gimbal  30 . A part of the gimbal  30 , in which the contact terminals have been formed, is cut and vertically bent, so that t e contact block  42  including the contact terminals can be formed. The contact block  42  is extended upward from the gimbal  30 , and an opening part is formed by bending th contact block  42  upward. 
   (The Fixed Base Section) 
   As shown in  FIG. 2 , the fixed base section  40  is fixed on a bottom face of the setting section  34 , which is provided at the center of the gimbal  30 . The fixed base section  40  has the contact block  42 , to which the slider  14  is detachably attached, an a clamp spring  44  facing to the contact block  42 . The contact block  42  and the clamp spring  44  are upwardly extended from an opening part of the gimbal  30 . The heights of the contact block  42  and the clamp spring  44  are nearly equal to the thickness of the slider  14 . 
   The clamp spring  44  elastically biases a side face of the slider  14 , which is the opposite face of the face including the electrodes, toward the contact block  42 , so that the slider  14  can be elastically clamped between the contact block  42  and the clamp spring  44 . By elastically biasing the slider  14  toward the contact block  42 , the electrodes of the slider  14  can be pressed onto the contact terminals of the contact block  42 , so that the slider  14  can be securely electrically connected to the cable patterns  36 . 
   In an example shown in  FIG. 6A , the electrodes  14   a  of the slider  14  are securely electrically connected to the contact terminals  42   a  of the contact block  42  even if the slider  14  is not correctly pressed when the clamp spring  44  presses the slider  14  onto the contact block  42 . If the slider is diagonally pressed with respect to the contact block  42  as shown in  FIG. 6B , a gap is formed between the electrodes  14   a  of the slide  14  and the contact terminals  42   a  of the contact block  42 , so that the slider  14  is not electrically connected to the cable patterns  36 . 
   In  FIG. 6A , an anisotropic electric conductive sheet  46  is adhered on the face of the contact block  42 , in which the contact terminals  42  are formed. A part of the anisotropic electric conductive sheet  46  compressed is capable of conducting electricity. Therefore, even if the slider  14  is diagonally pressed onto the contact block  42 , a part of the anisotropic electric conductive sheet  46 , which is compressed by the electrodes  14   a  and the contact terminals  42   a , is capable of electrically connecting them. Namely, even if the slider  14  is slightly inclined when it is diagonally pressed onto the contact block  42  by the clamp spring  44 , the anisotropic electric conductive sheet  46  is capable of securely electrically connecting the slider  14  to the cable patterns  36 . 
     FIG. 7  is a perspective view showing the slider  14  mounted on the fixed base section  40 . The clamp spring  44  is provided to face the contact block  42  on the upper face of the fixed base section  40 , and a side stopper  45  is provided set and positioned at a prescribed position with respect to the contact block  42 .  FIGS. 8A and 8B  show examples of the clamp spring  44 . In  FIG. 8A , a V-shaped pressing part  44   b  is extended from a fixed part  44   a . A front end of the pressing part is a free end. 
   In  FIG. 8B , the fixed part  44   a  and the V-shaped pressing part  44   b  are connected by a U-shaped bent part  44   c . As clearly shown in  FIG. 8B , in the case of supporting the pressing part  44   b  by the U-shaped bent part  44   c , a distance between the fixed part  44   a  and the pressing part  44   b  can be longer than that of the clamp spring  44  shown in FIG.  8 A. With this structure, a stroke of the clamping spring  44  for clamping and releasing the slider  14  can be long, so that the slider  14  can be easily attached and detached. Further, the clamp spring  44  is actuated within elastic limit, so a span of life of the clamp spring  44  can be extended.
 
By the U-shaped bent part  44   c , the fixed part  44   a  can be located on the inner side of the pressing part  44   b , so that the clamp spring  44  can be provided in a narrow space and bad influence to the floating characteristics can be restricted.
 
(The Press Mechanism)
 
   As shown in  FIG. 2 , the press mechanism  50  has a press pin  51 , which is provided under the center part of the fixed base section  40 , and a coil spring  52 , which covers the press pin  51 . The coil spring  52  makes an upper end of the press pin  51  contact a bottom face of the fixed base section  40  so as to apply a pressing force which presses the slider  14  supported by the gimbal  30  onto the surface of the recording medium. By adjusting the elasticity of the coil spring  52 , a load applied to the slider  14  is adjusted when the slider is floated by the rotation of the recording medium, so that a floating distance from the surface of the recording medium can be adjusted. 
   In  FIG. 9A , an upper part  51  a of the press pin  51  is formed into a smooth half-spherical shape. With this structure, the press mechanism  50  does not obstruct inclination of the slider  14  in optional directions. 
   In  FIG. 9B , an upper end of the press pin  51  is a flat face; a smooth half-spherical-shaped section  54  is expanded from the bottom face of the fixed base section  40  so as to contact the upper end of the press pin  51 . Since the contact part of the fixed base section  40  or the press pin  51  is formed into a smooth spherical shape, the fixed base section  50  can be inclined in optional directions. 
   The press mechanism  50  applies the pressing force or load, which is equal to an elastic force applied to the slider  14  by a suspension, to the slider  14  when the recording medium  12  is rotated to execute the reading and writing function test. Note that, a structure of the press mechanism  50  is not limited to that shown in FIG.  2 . 
   In another example of the press mechanism  50  shown in  FIG. 10 , the pressing force is applied to the slider  14  by elasticity of the gimbal  30  without using the press pin  51  and the coil spring  52 . The gimbal  30  is made of an elastic member, e.g., a leaf spring, and the slits  32  are formed in the gimbal  30 , so that the gimbal  30  can elastically apply a proper pressing force. The elastic pressing force applied by the gimbal  30  is used as a counter force against the lifting force for floating the slider  14 , so that the floating distance of the slider  14  can be adjusted. 
   (The Mounting Base of the Setting Plate) 
   As described above, the slider  14  is detachably attached to the arm section  22  of the setting plate  20  for executing the test. A structure of the arm section  22  and the mounting base  24  is shown in  FIGS. 11A and 11B . 
   In  FIG. 11A , the arm section  22  is set on the mounting base  24 ; in  FIG. 11B , the arm section  22  is detached from the mounting base  24 . Positioning pins  26  are provided so as to correctly position the arm section  22  on the mounting base  24 . 
   The arm section  22 , which has been correctly position on the mounting base  24 , may be fixed by air suction. 
   Many types of the sliders  14  exist and their sizes, arrangement of the electrodes, etc. are different. Therefore, the gimbal  30 , the contact block  42 , the clamp spring  44 , etc. of the setting plate  20  are different according to the sliders  14  to be tested. Thus, the arm section  22  can be separated from the mounting base  24  so as to exchange the arm section  22  and the setting plate  20  according to types of the sliders. Namely, many types of the sliders  14  can be effectively tested. In  FIG. 12 , an arm plate  22   a  is attached to the mounting base  24 , and the arm section  22  is detachably attached to the arm plate  22   a . The press pin  51  is provided to a front end part of the arm plate  22   a , and the arm section  22  is set on the arm plate  22   a . With this structure, the fixed base section  40  of the setting plate  20 , which is set on the arm section  22 , is pressed by the press pin  51 . In this case too, the arm section  22  including the setting plate  20  can be exchanged to test many types of the sliders  14 . In another case, the arm plate  22   a  may be exchanged to test many types of the sliders  14 . 
   In  FIG. 13 , a height adjusting mechanism for adjusting the height of the mounting base  24  and a direction adjusting mechanism for adjusting a direction of a surface of the mounting base  24  are provided in the mounting base  24 . A slide block  62  is pushed by a micrometer  60 . A sloping plate  64  and a parallel plate  66  are provided. The slide block  62  is reciprocally moved in the direction D 2  by the micrometer  60 . Namely, the height of the mounting base  24  can be adjusted by adjusting the position of the slide block  62 . 
   Adjust screws  68   a  and  68   b  are provided to adjust a direction or a heading of an upper surface of the mounting base  24 . The direction of the upper surface of the mounting base  24  can be adjusted by adjusting projection length of the adjust screws  68   a  and  68   b.    
   The thickness of the slider  14  and the distance between the slider  14  and the surface of the recording medium  12  are different according to the type of the sliders  14 . The height adjusting mechanism and the direction adjusting mechanism are used to precisely adjust the height of the mounting base  24 , etc. when the slider  14  to be tested is exchanged. 
   An example in which arrangement of the arm section  22  claim can be automatically controlled is shown in FIG.  14 . The position of the slider  14 , which has been mounted on the setting plate  20 , is detected and the arrangement of the arm section  22  is controlled on the basis of the results of the detection. A detecting section  70  detects a position, a height and inclination of the slider  14  set on the setting plate  20 . The detecting section  70  detects the inclination of the slider  14 , etc. by, for example, irradiating a laser beam toward the slider  14 . A control section  72  controls the micrometers  60  on the basis of the detected inclination of the slider  14 , etc. so as to position the slider  14  at the prescribed position Function rods  60   a  of the micrometers  60  are engaged between a base plate  24   a , which is fixed to the body proper  10 , and the arm section  22 . With this structure, the height and inclination of the arm section  22  are adjusted by respectively adjusting the projecting length of the function rods  60   a  of the micrometers  60 , so that the position of the slider  14  can be adjusted. The detecting section  70  actuates the micrometers  60 , and the position of the slider  14  detected by the detecting section is fed back. By feed-back controlling the position of the slider  14 , the position of the slider  14  can be correctly adjusted. 
   By the method of feed-back-controlling the position of the slider  14 , deviation of positions of the arm section  22  and the setting plate  20  can be disappeared, and the slider  14  can be correctly set. 
   Note that, in the above described embodiment, the micrometer(s)  60  is used as the position adjusting mechanism for adjusting the position of the a section, but the position adjusting mechanism may be constituted by other means, e.g., an adjustment screw(s) driven by a servo motor(s). 
   In the slider tester, the slider  14  can be solely tested and easily attached to and detached from the setting plate  20 , so that the efficiency of the slider test can be improved. The floating distance of the slider  14  from the surface of the recording medium  12  can be set as well as a slider mounted on an actual suspension. Therefore, the result of the reading and writing function test can be executed with proper accuracy, so that the sliders can be correctly judged. By securely selecting the good sliders, only the good sliders can be mounted onto actual suspensions, therefore efficiency and yield of manufacturing magnetic drive units can be improved. Further, manufacturing cost of magnetic drive units can be effectively reduced. 
   The invention may be embodied in other specific forms without departing from the spirit or essential characteristics thereof. The present embodiments are therefore to be considered in all respects as illustrative and not restrictive, the scope of the invention being indicated by the appended claims rather than by he foregoing description and all changes which come within the meaning and range of equivalency of the claims are therefore intended to be embraced therein.