JP5637667B2 - Head gimbal assembly - Google Patents

Description

  The present invention relates to a head gimbal assembly, and more particularly to a wiring layout on a suspension for transmitting a head slider signal.

  As a disk drive, devices using various types of disks such as an optical disk, a magneto-optical disk, and a flexible magnetic disk are known. Among them, a hard disk drive (HDD) is a computer system. It is used in many electronic devices such as a moving image recording / reproducing apparatus and a car navigation system.

  A magnetic disk used in the HDD has a plurality of data tracks and a plurality of servo tracks formed concentrically. Each servo track is composed of a plurality of servo sectors having address information. Each data track is composed of a plurality of data sectors including user data. Data sectors are recorded between servo sectors spaced apart in the circumferential direction. The head element portion of the head slider supported by the oscillating actuator accesses the desired data sector according to the address information in the servo sector, thereby writing data to the data sector and data from the data sector. Reading can be performed.

  In order to improve the recording density of the magnetic disk, it is important to reduce the clearance (interval) between the head element portion that floats on the magnetic disk and the magnetic disk and the change thereof. For this reason, several mechanisms for adjusting the clearance have been proposed. One of them is provided with a heater in the head slider, and the clearance is adjusted by heating the head element portion with the heater. In this specification, this is called TFC (Thermal Fly-height Control). The TFC supplies a current to the heater to generate heat, and causes the head element portion to protrude by thermal expansion. As a result, the clearance between the magnetic disk and the head element portion is reduced.

  The TFC compensates for an increase in clearance due to a decrease in temperature by increasing the heater power in response to a decrease in temperature and causing the head element portion to protrude by thermal expansion. If the temperature rises, the heater power is decreased to compensate for the decrease in clearance. Further, when the altitude increases and the atmospheric pressure decreases, the flying height of the slider decreases. For this reason, the clearance between the head element portion and the magnetic disk also decreases due to the decrease in the atmospheric pressure. Therefore, if the temperature is constant, the TFC decreases the heater power as the atmospheric pressure decreases and increases the heater power as the atmospheric pressure increases.

  The slider flying height and heater efficiency differ for each head and slider. for that reason. In a test process in HDD manufacturing, appropriate parameters for TFC are set for each head slider. Specifically, the HDD determines the heater power value at which the head slider and the magnetic disk are in contact with each other, and according to the value, the relationship between the temperature and the heater power and the relationship between the atmospheric pressure and the heater power are determined. Identify. These relationships vary depending on the radial position on the magnetic disk. Therefore, the HDD performs the contact measurement at different positions on the magnetic disk, and specifies the relationship according to the radial position.

  However, the temperature range and atmospheric pressure range of measurements that can be performed in the test process are limited. In the HDD test process, it is practically impossible to measure at all radial positions on the magnetic disk. Therefore, specify the exact relationship between temperature and heater power over the entire temperature range, identify the exact relationship between air pressure and heater power over the entire atmospheric pressure range, and the above two exact relationships over the entire recording area. It is impossible to specify.

  Therefore, in an actual HDD design, a predetermined clearance margin is secured to avoid head-disk contact due to an error between the estimated clearance and the actual clearance in TFC. The HDD performs TFC using the clear run including the clearance margin as a target clearance.

  In order to realize further data recording density, it is necessary to reduce the clearance margin. One method for realizing this is to constantly monitor the contact between the head slider and the magnetic disk, and to reduce the heater power and increase the clearance when head-disk contact occurs. A technique for mounting a sensor element for detecting contact in the head slider in this manner is disclosed in, for example, Patent Document 1.

JP 2008-16158 A JP 2002-192742 A

  A plurality of conductor lines that transmit signals (including ground potential) to elements on the head slider are disposed on the suspension. Due to the increase in recording frequency accompanying the increase in BPI, crosstalk from the write signal on the write signal line to the read signal on the read signal line becomes a problem. The generation of the crosstalk current due to the write signal reduces the sense current that can be supplied to the read element and lowers the sensitivity of the read element.

  In order to suppress this crosstalk, it is effective to increase the distance between the write signal line and the read signal line. When the head slider has a heater element, two heater signal lines are provided on the suspension in addition to two read signal lines (read signal line pair) and two write signal lines (write signal line pair). (Including the case where one is a ground line).

  Patent Document 2 proposes arranging two heater signal lines between a read signal line pair and a write signal line pair. The signal on the heater signal line can be regarded as a signal having a very low frequency compared to the write signal. Therefore, there is no crosstalk of the heater signal to the read signal, and the distance between the write signal line pair and the read signal line pair can be increased, so that the crosstalk current in the lead wire can be reduced.

  However, as described above, when the head slider has a contact sensor element, a new study is required for the wiring layout on the suspension. When the contact sensor element is mounted on the head slider in addition to the heater element, typically, eight conductor lines (including a ground line) are arranged on the suspension. Two conductor lines are assigned to each of the read element, the write element, the heater element, and the sensor element.

  In the wiring layout on the suspension, in addition to reducing crosstalk to the lead signal, it is important to prevent excessive input to the contact sensor element and to consider the heat balance of the signal transmission wiring. From the viewpoint of structure simplicity and contact detection accuracy, the contact sensor element is preferably formed of a metal thin film having a high thermal sensitivity of resistance. Such a contact sensor element is easily damaged by an excessive current. Also, if the heat from the signal transmission wiring is unbalanced, the aerodynamic characteristics of the suspension change due to thermal deformation of the gimbal, which adversely affects the positioning accuracy of the head slider.

  A head gimbal assembly according to an aspect of the present invention includes a suspension, a head slider fixed on the suspension, a write element, a read element, a heater element, and a contact sensor formed on the head slider. An element and a signal transmission line bundle including a plurality of signal transmission lines arranged side by side for transmitting a signal of the head slider. The signal transmission line bundle includes a read signal transmission line pair consisting of adjacent read signal transmission lines, a write signal transmission line pair consisting of adjacent write signal transmission lines, a heater signal transmission line pair, and a contact sensor signal transmission line pair. Have At least one heater signal transmission line of the heater signal transmission line pair is wired between the write signal transmission line pair and the read signal transmission line pair. Between the write signal transmission line pair and the contact sensor signal transmission line pair, at least one heater signal transmission line of the heater signal line pair is wired. With this wiring layout, high-precision clearance control can be performed by the heater element and contact sensor element on the head slider, while reducing the sensitivity of the read element, the reliability of the head slider, and the positioning system. it can.

  A head gimbal assembly according to another aspect of the present invention includes a suspension, a head slider fixed on the suspension, and a write element, a read element, a heater element, and a contact formed on the head slider. A sensor element; and an optical element that generates heat-assisted recording light; and a signal transmission line bundle including a plurality of signal transmission lines arranged to transmit a signal of the head slider. The signal transmission line bundle includes a read signal transmission line pair consisting of adjacent read signal transmission lines, a write signal transmission line pair consisting of adjacent write signal transmission lines, a heater signal transmission line pair, and an optical element signal transmission line pair. And a contact sensor signal transmission line pair. At least one signal transmission line of the heater signal line pair and the optical element signal transmission line pair is wired between the write signal line pair and the read signal line pair. At least one signal transmission line of the heater signal line pair and the optical element signal transmission line pair is wired between the write signal line pair and the contact sensor signal line pair. With this wiring layout, high-precision clearance control can be performed by the heater element and contact sensor element on the head slider, while reducing the sensitivity of the read element, the reliability of the head slider, and the positioning system. it can.

  In a preferred configuration, the contact sensor signal transmission line pair includes adjacent contact sensor signal transmissions. Thereby, a contact sensor signal can be transmitted more correctly.

  In a preferred configuration, the signal transmission wiring bundle branches into a first branch signal transmission wiring bundle and a second branch signal transmission wiring bundle in the vicinity of the head slider, and the first branch signal transmission wiring bundle, Each of the second branch signal transmission wiring bundles includes at least one of the lead signal line and the contact sensor signal line. Thereby, the branch signal transmission wiring bundle is not composed of only signal transmission lines having a large transmission current amount, which is preferable in terms of heat balance.

  More preferably, each of the first branch signal transmission wiring bundle and the second branch signal transmission wiring bundle is composed of half the signal transmission lines of the signal transmission wiring bundle. This configuration is preferable in terms of layout balance and heat balance. When the signal transmission wiring bundle is composed of an odd number of signal transmission wirings, one branch signal transmission wiring bundle composed of half the signal transmission lines is connected to the other half of the signal transmission wiring. It has one more signal transmission line than the branch signal transmission wiring bundle. This is the same in the following description.

  In a preferred configuration, the signal transmission line bundle includes a pair of piezoelectric signal transmission lines for transmitting a signal of a piezoelectric element, and at least of the heater signal line pair is interposed between the piezoelectric signal transmission line pair and the read signal line pair. One heater signal transmission line is wired. Thereby, crosstalk from the piezo signal transmission line to the read signal line can be reduced.

  In a preferred configuration, the signal transmission wiring bundle branches into a first branch signal transmission wiring bundle and a second branch signal transmission wiring bundle in the vicinity of the head slider, and the first branch signal transmission wiring bundle, Each of the second branch signal transmission wiring bundles includes at least one of the lead signal line, the contact sensor signal line, and the piezo signal transmission line. Thereby, the branch signal transmission wiring bundle is not composed of only signal transmission lines having a large transmission current amount, which is preferable in terms of heat balance.

  In a preferred configuration, connection pads of the plurality of signal transmission lines are arranged on an end face of the head slider, and two connection pads of the contact sensor element are arranged at both ends. Thereby, the wiring resistance of the contact sensor element in the head slider can be reduced.

In a preferred configuration, one heater signal transmission line of the heater signal line pair is a ground line, and the ground line is adjacent to the read signal transmission line pair.
In a preferred configuration, one signal transmission line of the heater signal line pair and / or one signal transmission line of the optical element signal transmission line pair is a ground line, and the ground line is adjacent to the read signal transmission line pair. ing. As a result, crosstalk to the read signal transmission line can be further reduced.

  In a preferred configuration, the signal transmission wiring bundle branches into a first branch signal transmission wiring bundle and a second branch signal transmission wiring bundle in the vicinity of the head slider, and the first branch signal transmission wiring bundle, Each of the second branch signal transmission wiring bundles is composed of half the signal transmission lines of the signal transmission wiring bundle, and each of the first branch signal transmission wiring bundle and the second branch signal transmission wiring bundle is , Including at least one of the read signal transmission line and the contact sensor signal transmission line, wherein connection pads of the plurality of signal transmission lines are arranged on an end surface of the head slider, and two of the contact sensor elements are arranged. One connection pad is arranged at both ends. Thereby, it is possible to realize a preferable heat balance and reduce the wiring resistance of the contact sensor element in the head slider.

  According to the present invention, high precision clearance control is performed by the heater element and the contact sensor element on the head slider, and the sensitivity of the read element, the reliability of the head slider and the positioning system are reduced. Can do.

In this embodiment, it is a block diagram which shows typically the whole structure of a hard-disk drive. In this embodiment, it is a top view which shows typically the structure of a head gimbal assembly. In this embodiment, it is a figure which shows typically one of the preferable layouts of a signal transmission wiring. In this embodiment, it is a figure which shows typically the preferable arrangement | sequence of the connection pad of a head slider. In this embodiment, it is a figure which shows typically one of the preferable layouts of a signal transmission wiring. In this embodiment, it is a figure which shows typically one of the preferable layouts of a signal transmission wiring. In this embodiment, it is a figure which shows typically one of the preferable layouts of a signal transmission wiring. In this embodiment, it is a figure which shows typically the preferable layout of the signal transmission wiring which has the signal transmission line pair of an optical element. In this embodiment, it is a figure which shows typically the preferable layout of the signal transmission wiring which has the signal transmission line pair of a piezoelectric element.

  Embodiments to which the present invention is applied will be described below. For clarity of explanation, the following description and drawings are omitted and simplified as appropriate. Moreover, in each drawing, the same code | symbol is attached | subjected to the same element and the duplication description is abbreviate | omitted as needed for clarification of description. In the following, an embodiment in which the present invention is applied to a hard disk drive (HDD) which is an example of a disk drive will be described.

  In addition to the read element and the write element, the head element portion on the head slider of this embodiment includes a heater element for adjusting the clearance between the magnetic disk and the head element section, and further includes a head element and a magnetic disk. A contact sensor element for detecting contact. The HDD can control the clearance between the head element portion and the magnetic disk by controlling the heat generation from the heater element. Such clearance control using the heater element on the slider is referred to as TFC (Thermal Fly height Control).

  The HDD further monitors the contact between the head slider and the magnetic disk by a contact sensor element. When the contact sensor element detects contact, the HDD decreases the heater power to the heater element and increases the clear run. As a result, the HDD can perform clear run control with a small clearance margin.

  The contact sensor element is composed of a metal thin film having a large temperature resistance coefficient. The HDD can detect the contact between the magnetic disk and the head slider by measuring the resistance value of the metal thin film. As described above, by configuring the contact sensor element with the metal resistive thin film, the contact between the magnetic disk and the head slider (head element portion) can be detected with high accuracy. Moreover, the head element part which has a contact sensor element can be comprised with a simple structure.

  The present embodiment is characterized by the arrangement of conductor lines for transmitting signals to the head element section and the arrangement of connection pads on the head slider. A conductor line connected to the heater element transmits power to the heater. In this specification, a conductor line including this conductor line and connected to the four elements is referred to as a signal transmission line. One of the conductor lines of the heater element may be a ground line. In such a configuration, the ground line is also called a signal transmission line. A group of these signal transmission lines is called a signal transmission wiring.

  Before specifically describing the signal transmission wiring layout and the connection pad arrangement on the head slider in this embodiment, the entire structure of the HDD to which the present invention can be applied will be described. FIG. 1 is a top view schematically showing a basic configuration of the HDD in the present embodiment. The magnetic disk 11 is an example of a disk for storing data, and records data by magnetizing the magnetic layer. The base 12 constitutes an enclosure by being fixed to a cover (not shown) that closes the upper opening of the base 12 via a gasket (not shown), and accommodates each component of the HDD 1.

  A spindle motor 13 fixed to the bottom surface of the base 12 rotates the magnetic disk 11 fixed thereto at a predetermined angular velocity. The head slider 15 for accessing the magnetic disk 11 has a head element unit for writing data to and reading data from the magnetic disk 11, and a slider on which the head element unit is formed.

  The actuator 16 supports the head slider 15 and moves it. The actuator 16 is rotatably held on a rotary shaft 17 and is driven by a voice coil motor (VCM) 19. The actuator 16 includes constituent members coupled in order of a suspension 161, an arm 162, and a voice coil 163 from the tip portion where the head slider 15 is disposed. The voice coil 163 is a part of the VCM 19.

  When the actuator 16 rotates on the shaft 17, the head slider 15 moves in the radial direction on the rotating magnetic disk 11. The head slider 15 floats on the magnetic disk 11 with a predetermined clearance by balancing the buoyancy generated on the flying surface of the slider facing the magnetic disk 11 and the pressing force by the suspension 161.

  The signal of the head slider 15 is transmitted by a signal transmission wiring 164 disposed on the actuator 16. Typically, the signal transmission wiring 164 is formed on the metal layer (backing metal layer) of the suspension 161 via a polyimide insulating layer. Further, a polyimide overcoat layer is laminated on the signal transmission wiring 164. Each signal transmission line (conductor line) of the signal transmission wiring 164 is separated by polyimide.

  One end of the signal transmission wiring 164 is electrically and physically connected to the head slider 15 and the other end is electrically and physically connected to an FPC (Flexible Printed Circuit) 18 on which a preamplifier IC 182 is mounted. Typically, the FPC 18 is formed on a plate made of metal or resin. The signal transmission wiring 164 transmits a signal between the head slider 15 and the preamplifier IC 182 or a signal between the head slider 15 and another circuit connected via the FPC 18.

  Typically, the read signal and the write signal are transmitted through the preamplifier IC 182. A configuration is also known in which the heater element signal is supplied from another circuit without passing through the preamplifier IC 182. The FPC 18 is electrically connected to a control circuit board (not shown) mounted on the outer back surface of the base 12 via the connector 181. The FPC 18 transmits a signal between the control circuit and the preamplifier IC 182. The control circuit on the control circuit board performs operation control and signal processing of the HDD 1.

  FIG. 2 is a plan view schematically showing a configuration of a head gimbal assembly (HGA) 160 that is an assembly of the head slider 15 and the suspension 161, and shows a surface facing the recording surface of the magnetic disk 11. . The suspension 161 includes a gimbal 611, a load beam 612, and a mount plate 613. The load beam 612 has a hinge portion 621 and exhibits a spring function for pressing the head slider 15 toward the disk. The load beam 612 has a rigidity function for supporting the gimbal 611 in a stable posture when the actuator 16 rotates. The base plate 613 has a strength for fixing the load beam 612 to the arm 162.

  The gimbal 611 can be formed of stainless steel, for example, and has a desired elasticity. At the front part of the gimbal 611, a tongue-like gimbal tongue is formed, and the head slider 15 is fixed thereon by a low elastic epoxy resin or the like. The gimbal tongue rotates the head slider 15 around the dimple of the load beam 612 in the pitch direction or the roll direction. In this specification, the side on which the head slider 15 is fixed is referred to as a front side, and the side on which the base plate 613 is fixed is referred to as a rear side.

  The signal transmission wiring 164 is formed on the gimbal 611. The gimbal 611 has a tail portion 614 extending from the main body portion toward the preamplifier IC 182 (rear). The tip of the tail portion 614 is a multi-connector tab 169 that is electrically and physically connected to the FPC 18 on which the preamplifier IC 18 is mounted. In this example, the multi-connector tab 169 has eight connection pads, and the signal transmission line of the signal transmission wiring 164 is connected to each of them. As described above, the signal transmission wiring 164 is routed on the gimbal 611 between the connection pad of the head slider 15 and the connection pad of the multi-connector tab 169.

  The HDD 1 can have one or a plurality of magnetic disks. The actuator 16 has the same number of HGAs 160 as the recording surface of the mounted magnetic disk. They have the same structure and have exactly the same or symmetrical structure. The signal transmission wiring layout of the present invention is not limited to the above suspension structure, and can be applied to suspensions having other structures.

  Hereinafter, the layout of the signal transmission wiring 164 in the present embodiment will be specifically described. FIG. 3 schematically shows one preferred layout of the signal transmission wiring 164. FIG. 3 shows a wiring layout viewed from the magnetic disk 11 or a wiring layout viewed from the back (from the gimbal 611). A mirror image of any of the transmission wiring layouts shown below has the same effect as the transmission wiring layout. Therefore, the mirror image of the transmission wiring layout described below is also a preferred configuration of the present invention.

  The head slider 15 includes a write element 151, a read element 152, a heater element 153, and a contact sensor element 154. In FIG. 3, the upper end of the head slider 15 is a trailing end, and the lower end is a leading end. A plurality of connection pads are arranged on the trailing end of the head slider 15. In this configuration, the head slider 15 has eight connection pads.

  The connection pads are connected to the write element 151, the read element 152, the heater element 153, and the contact sensor element 154 by internal wiring on the head slider. In FIG. 3, W is a connection pad (write pad) of the write element 151, R is a connection pad (read pad) of the read element 152, H is a connection pad (heater pad) of the heater element 153, and a contact sensor. S is attached to the connection pad (sensor pad) of the element 154. Two connection pads are connected to each element.

  In general, the write element 151 is composed of one or a plurality of magnetic poles and coils, and the read element 152 is composed of a magnetoresistive element. The heater element 153 can be formed of, for example, a permalloy meandering thin film resistor. The contact sensor element 154 is a thin film resistor formed of a metal having a large temperature resistance coefficient. A metal generally used in the head element portion such as nickel, iron or cobalt can be used. The contact sensor element 154 may be a magnetoresistive effect element that is one of thin film resistors.

  The HDD 1 controls the amount of heat generated by controlling the power to the heater element 153. The amount of thermal expansion of the head element portion changes according to the amount of heat generated by the heater element 153, and the clearance can be changed. The control circuit of the HDD 1 controls the clear run by controlling the power to the heater element 153.

  The control circuit monitors the contact between the head slider 15 and the magnetic disk 11 by the contact sensor element 154. When the head slider 15 and the magnetic disk 11 come into contact with each other, the temperature of the contact sensor element 154 rises and the resistance value increases accordingly. The control circuit can detect contact between the head slider 15 and the magnetic disk 11 by monitoring the resistance value of the contact sensor element 154. In a preferred example, the control circuit constantly monitors the resistance value of the contact sensor element 154 including during recording and reproduction. When the resistance value of the contact sensor element 154 exceeds a threshold value and a specified time elapses, the control circuit causes contact. It is determined that

  When contact is detected by the contact sensor element 154, the control circuit increases the clear run by decreasing the heater power to the heater element 153. Thus, by monitoring the contact between the head slider 15 and the magnetic disk 11, a smaller clearance can be realized. Note that the present invention can also be applied to an HDD that uses contact detection by the contact sensor element 154 in another method. For example, the control circuit may monitor the resistance value of the contact sensor element 154 only during the following process.

  As shown in FIG. 3, the connection pads of the head slider 15 are arranged as an example in the left-right direction at the trailing end. The left-right direction is a direction perpendicular to the sliding direction and the flying direction of the head slider 15. A typical head slider 15 has such a pad arrangement and is preferably arranged in a line in the left-right direction. The present invention can be applied to other pad arrangements.

  In the configuration of FIG. 3, the connection pads of the head slider 15 are arranged in the following order: sensor pad, heater pad, write pad, write pad, read pad, lead pad, heater pad, and sensor pad. Has been. These connection pads are connected to signal transmission lines for signals (including ground) of the respective elements. In FIG. 3, reference numerals of corresponding elements are given to the respective signal wirings.

  A signal transmission line extending from the four connection pads (SHWW) on the left half extends backward (toward the multi-connector tab 169) along the left side surface of the head slider 15. In this signal transmission line bundle 641, the four signal transmission lines are parallel to each other. On the other hand, the signal transmission line extending from the four connection pads (RRHS) in the right half extends backward (toward the multi-connector 169) along the right side surface of the head slider 15. In the signal transmission line bundle 642, the four signal transmission lines are parallel to each other.

  The two bundles of signal transmission lines merge at the rear of the leading end of the head slider 15 to form one bundle 643, and further extend rearward to reach the multi-connector 169. In the bundle 643 composed of eight signal transmission lines after joining, the signal transmission lines are parallel to each other. In FIG. 3, the signal transmission lines of the respective elements are denoted by the same reference numerals as the connection pads.

  W for signal transmission lines that transmit write signals, R for signal transmission lines that transmit read signals, H for signal transmission lines that transmit heater signals (meaning heater power), and sensor signals The signal line to be attached is marked with S. In addition, although it is preferable that the signal transmission line which comprises each of the bundles 641-643 is mutually parallel, it does not necessarily need to be so. Typically, in the signal transmission wiring, all the signal transmission lines are formed on the same surface. Therefore, the signal transmission lines do not cross each other.

  In the signal transmission wiring layout of FIG. 3, the signal transmission line branches into two bundles 641 and 642 in the vicinity thereof so as to avoid the head slider 15. On the other hand, behind the leading end, the signal transmission lines form a single bundle 643, which extends to the multi-connector tab 169 without changing the arrangement order. In the signal transmission wiring layout, since the signal transmission wiring length in the vicinity of the head slider 15 is short, the portion behind the leading end having a long distance is more important in terms of signal quality (crosstalk).

  In the configuration of FIG. 3, the arrangement order of the signal transmission wirings behind the leading end (signal transmission line bundle 643) is WWHSSHRR from the left end in FIG. The signal transmission lines of the read element and the write element are composed of adjacent signal transmission line pairs. There is no other signal transmission line between adjacent signal transmission lines. In each of the write signal transmission line pair WW and the read signal transmission line pair RR, the two conductor lines are adjacent to each other. Thereby, the signal of these elements can be transmitted more correctly. The signal of the heater element 153 is less changed than other signals, and there is no substantial problem even if the two conductor lines of the signal transmission wiring pair HH are separated.

  One of the important points in this configuration is that the heater signal transmission line H exists between the write signal transmission line pair WW and the read signal transmission line pair RR, and the write signal line pair WW and the contact sensor signal transmission line S. The heater signal transmission line H is also wired between the two. By arranging the heater signal transmission line H between the read signal transmission line pair RR and the write signal transmission line pair WW, the distance between them becomes longer, and crosstalk from the write signal transmission line to the read signal transmission line is reduced. can do.

  Since the heater signal has a larger time constant than the write signal and the frequency of change is low, crosstalk to the read signal due to the heater signal does not occur. In crosstalk, the time constant is an important characteristic. The time constant is the time required for signal change. It is the time for the signal to change from a lower level to a target high level, or to reach a target lower level from a high level. In typical control, the time constant at the rise and fall of the signal is the same, and is constant regardless of the level of signal change.

  As described above, the contact sensor element 154 is formed of a metal thin film. Therefore, there is a high possibility that the contact sensor element 154 is damaged when an excessive current flows. In the contact sensor signal transmission line adjacent to the write signal transmission line, a crosstalk current due to the write signal is likely to occur. This crosstalk current is added to the current for resistance detection of the contact sensor element 154, and there is a possibility that the contact sensor element 154 is damaged. Therefore, as shown in FIG. 3, the contact sensor signal transmission line pair is a pair of adjacent transmission lines, and the heater signal transmission line W is wired between the write signal transmission line pair WW and the contact sensor signal transmission line pair SS. It is desirable to do. This wiring increases the distance between the write signal transmission line pair WW and the contact sensor signal transmission line pair SS, reduces the possibility of occurrence of excessive current in the contact sensor signal transmission line S, and improves the reliability. .

  Further, as for the influence from the write signal transmission line pair WW, the influence on the read signal transmission line pair RR is more important than the influence on the sensor signal transmission line pair SS. Therefore, it is preferable that the sensor signal transmission line pair SS exists between the read signal transmission line pair RR and the write signal transmission line pair WW. The configuration example of FIG. 3 satisfies this condition. Further, a configuration in which the contact sensor signal transmission line pairs are adjacent to each other is more desirable.

  There is another important point in the layout of signal transmission wiring. It is heat balance in signal transmission wiring. In the signal transmission wiring, signal transmission lines that have a large transmission current value and can serve as a heat source are a light signal transmission line and a heater signal transmission line. It is not preferable that the write signal transmission line pair WW and the heater signal transmission line pair HH are all integrated into one of the branched signal transmission line bundles. That is, it is preferable to wire the signal transmission lines so that a part of these signal transmission lines is in the signal transmission line bundle 641 and the other part is in the signal transmission line bundle 642.

  In the configuration of FIG. 3, two write signal transmission lines W and one heater signal transmission line H are wired in the left branch bundle 641. Another heater signal transmission line H is wired in the right branch bundle 642. In this configuration, one signal transmission line of the write signal transmission line and the heater signal transmission line is separated from the other signal transmission lines and wired on the opposite side of the head slider 15 with the head slider 15 interposed therebetween. As a result, heat in the signal transmission wiring can be prevented from being concentrated only on one side of the head slider 15, and positioning accuracy can be prevented from being lowered due to a change in suspension dynamics due to thermal deformation.

  The contact sensor element 154 is an element that measures a resistance change. Therefore, it is important that the signal transmission line has a low resistance. This applies not only to the signal transmission line on the suspension but also to the signal transmission line in the head slider 15. Therefore, the connection pads of the contact sensor element are preferably formed at both ends of the pad row on the trailing end face of the head slider. Thereby, the signal transmission line of the contact sensor element 154 can be made thicker easily in the head slider 15.

  FIG. 4 schematically shows the connection pad row on the leading end face. In the top view of FIG. 4, the contact sensor pads S are at both ends of the pad row. In the figure below, the two contact sensor pads S are only on one side. A hatched portion in each figure indicates a signal transmission line (electrode) in the head slider 15. As can be easily understood from the two figures, by arranging the contact sensor pads S at both ends of the pad row, the wiring in the head slider 15 can be made thicker, and the resistance change of the contact sensor 154 can be reduced by the S / N ratio. It can be measured well.

  As shown in the preferred configuration example of FIG. 3, the signal transmission line bundle 643 is preferably branched into two signal transmission line bundles 641 and 642 composed of half of the signal transmission lines. When the signal transmission wiring is composed of an odd number of signal transmission lines, the difference in the number of the signal transmission line bundles after the branching is 1 in the configuration in which the signal transmission wiring is branched into two signal transmission line bundles. In the case of having this configuration, the signal transmission lines from the contact sensor pads at both ends are two signal transmission lines extending in the center in the signal transmission line bundle 643 after joining. Therefore, the present configuration shown in FIG. 3 is a preferable configuration also from the viewpoint of reducing the resistance of the head / slider wiring of the contact sensor element 154.

  For heater signal transmission, both balanced transmission and unbalanced transmission are possible. In unbalanced transmission, one signal transmission line H of the heater signal transmission line pair HH is a ground line G. In this configuration, as shown in FIG. 3, the ground line G is preferably adjacent to the read signal transmission line pair RR. This is because the ground line has less noise than the other signal transmission line, and therefore, adverse effects on the read signal can be further reduced.

  FIG. 5 schematically shows another preferred configuration in the present embodiment. One difference from the configuration of FIG. 3 is that the arrangement order of the signal transmission lines is reversed. As described above, in the present embodiment, one array and its mirror image array have the same effect, and thus are not substantially different. Another difference is that the heater signal transmission line H wired between the read signal transmission line pair RR and the contact sensor signal transmission line pair SS in the configuration of FIG. 3 is in contact with the read signal transmission line pair RR interposed therebetween. This is the point arranged on the opposite side of the sensor signal transmission line pair SS. With the change in the arrangement of the signal transmission lines, the arrangement of the connection pads also changes.

  In the configuration of FIG. 5 as well, adjacent to the signal transmission line pair of elements other than the heater element 153, the heater signal transmission line H and the contact sensor signal transmission line pair between the read signal transmission line pair RR and the write signal transmission line pair WW. Each condition of the heater signal transmission line H between the SS and the write signal transmission line pair WW is satisfied.

  Of the heater signal transmission line H and the write signal transmission line W, three are in the branched signal transmission line bundle 642 and the other is in the other signal transmission line bundle 641. Furthermore, contact sensor pads are formed at both ends of the pad row. In order to increase the distance between the read signal transmission line pair RR and the write signal transmission line pair WW, the configuration of FIG. 3 is preferable to the configuration of FIG. In other respects, the configuration of FIG. 5 has the same effects as the configuration of FIG. When one of the heater signal transmission lines is the ground line G, the heater signal transmission line adjacent to the lead signal transmission line R is preferably the ground line G, as in the configuration of FIG.

  FIG. 6 schematically shows another preferred configuration in the present embodiment. The difference from the configuration in FIG. 3 is that the contact sensor signal transmission line pair SS and the write signal transmission line pair WW are interchanged. With the change in the arrangement of the signal transmission lines, the arrangement of the connection pads also changes. Also in this configuration, adjacent to the signal transmission line pair of elements other than the heater element 153, the heater signal transmission line H between the read signal transmission line pair RR and the write signal transmission line pair WW, and the contact sensor signal transmission line pair SS Each condition of the heater signal transmission line H between the write signal transmission line pair WW is satisfied.

  In this configuration, two of the heater signal transmission line H and the write signal transmission line W are in one signal transmission line bundle 641 after branching, and the other two are in the other signal transmission line bundle 642. It is in. Therefore, this configuration is superior to the configuration of FIG. 3 in terms of heat balance. On the other hand, the contact sensor pads are arranged only on one side of the pad row, and the distance between the read signal transmission line pair RR and the write signal transmission line pair WW is smaller than the distance in the configuration of FIG. In these respects, the configuration of FIG. 3 is preferable to the configuration of FIG. When one of the heater signal transmission lines is a ground line, the heater signal transmission line adjacent to the lead signal transmission line R is preferably the ground line G, as in the configuration of FIG.

  FIG. 7 schematically shows another preferred configuration in the present embodiment. The difference from the configuration of FIG. 3 is that the contact sensor signal transmission line pair SS and the read signal transmission line pair RR are interchanged. With the change in the arrangement of the signal transmission lines, the arrangement of the connection pads also changes. Also in this configuration, adjacent to the signal transmission line pair of elements other than the heater element 153, the heater signal transmission line H between the read signal transmission line pair RR and the write signal transmission line pair WW, and the contact sensor signal transmission line pair SS Each condition of the heater signal transmission line H between the write signal transmission line pair WW is satisfied.

  In the configuration of FIG. 7, as in the configuration of FIG. 3, among the heater signal transmission line H and the write signal transmission line W, three are in the branched signal transmission line bundle 641 and the other is the other signal transmission. It is in the wire bundle 642. Since both adjacent signal transmission lines of the read signal transmission line pair RR are heater signal transmission lines H, any heater signal transmission line may be a ground line in unbalanced transmission. On the other hand, in the configuration of FIG. 7, the contact sensor pads are arranged only on one side of the pad row, and the distance between the read signal transmission line pair RR and the write signal transmission line pair WW is larger than the distance in the configuration of FIG. Is also small. In these respects, the configuration of FIG. 3 is preferable to the configuration of FIG.

  As can be understood from the above description, the crosstalk from the write signal transmission line to the read signal transmission line, the crosstalk from the write signal transmission line to the sensor signal transmission line, the heat balance of the signal transmission wiring, and the connection pad arrangement In view of the above, the signal transmission wiring layout shown in FIG. 3 is most preferable.

  In the configuration described with reference to FIGS. 3 to 7, the head slider 15 includes a write element 151, a read element 152, a heater element 153, and a contact sensor element 154. As a technique for improving the recording density, heat-assisted recording is known. Thermally assisted recording records magnetic data by a recording magnetic field from a write element while applying energy to the magnetic recording layer.

  A head slider for thermally assisted recording has an element for applying heat to the magnetic disk. The element used for the heat-assisted recording is a heater for applying heat or an optical element for supplying light. In a configuration in which a light emitting element is formed on the head slider 15 for heat assist by light, the signal transmission wiring may include a signal transmission line to the light emitting element. In such a configuration, the signal transmission wiring has ten signal transmission lines.

  FIG. 8 shows a preferred example of a layout of signal transmission wiring to a head slider having a read element, a write element, a heater element, a contact sensor element, and an optical element. An arrangement of signal transmission line bundles before branching in the vicinity of the head slider 15 is shown. Each alphabet in FIG. 8 indicates a signal transmission line to the element, and O indicates a signal transmission line to the optical element. FIG. 8 shows 24 preferred layout examples.

  In terms of crosstalk and heat balance, the signal transmission line to the optical element can be regarded as having the same properties as the heater element signal transmission line. In the ten signal transmission lines, the signal transmission line pairs other than the heater signal transmission line pair HH and the optical element signal transmission line pair OO are configured by adjacent corresponding signal transmission lines. At least one of the heater signal transmission line H or the optical element signal transmission line O is wired between the write signal transmission line pair WW and the read signal transmission line pair RR. Further, at least one of the heater signal transmission line H or the optical element signal transmission line O is wired between the write signal transmission line pair WW and the contact sensor signal transmission line pair SS.

  From the viewpoint of heat balance, the signal transmission line bundle on the left and right half is not composed of only the write signal transmission line W, the heater signal transmission line H, and the optical element signal transmission line O, and other read signal transmission lines R or contacts. A sensor signal transmission line S is included. In this example, the signal transmission wiring is branched into half (five) signal transmission line bundles on the left and right. All layouts in FIG. 8 have a contact sensor signal transmission line pair SS in the center. This pair branches into different signal transmission line bundles. Therefore, the contact sensor signal transmission line S is included in both signal transmission line bundles. In the connection pad row of the head slider, the contact sensor pads are located at both ends.

  In the layout shown in FIG. 8, the distance between the write signal transmission line pair WW and the read signal transmission line pair RR in the upper six layouts is the largest. That is, these pairs are at both ends of the signal transmission line bundle, and all other signal transmission lines are wired between them. In this respect, these layouts are preferred over other layouts. Further, between the write signal transmission line pair WW and the read signal transmission line pair RR and between the write signal transmission line pair WW and the contact sensor signal transmission line pair, the heater signal transmission line H and the optical element signal transmission are provided. It is preferable that two or more signal transmission lines of the line O are wired. The above six layouts also satisfy this condition.

  When one heater signal transmission line pair HH and / or one optical element signal transmission line pair OO is a ground line, the ground line is a signal transmission line adjacent to the read signal transmission line pair RR. Is preferred. This is the same as the above eight signal transmission lines. If the heater signal transmission line pair HH and the optical element signal transmission line pair OO share a ground line, the ground line can be regarded as both a heater signal transmission line and an optical element signal transmission line. In this configuration, since the signal transmission wiring is composed of nine signal transmission lines, one signal transmission line bundle branched in half is composed of four (half) signal transmission lines, and the other signal transmission line bundle is It consists of five (half) signal transmission lines.

  FIG. 9 shows a preferred example of a layout of signal transmission wiring on an HGA having a read element, a write element, a heater element, a contact sensor element, and a piezo element. The piezo element is disposed on the head slider 15 or on the suspension 161 in the vicinity of the head slider 15. The position of the head slider 15 can be finely adjusted by extending or contracting one or two piezoelectric elements. In FIG. 9, the piezo signal transmission line is indicated by P, and when one is a ground line, the line is indicated by Pg.

  Since the piezo signal transmission line pair PP transmits a high-frequency (small time constant) signal, it can be regarded as having the same characteristics as the write signal transmission line in terms of crosstalk. Accordingly, it is preferable that heater signal transmission lines are wired between the pair and the read signal line pair RR and further between the contact sensor signal line pair SS (upper two layout examples).

  When one of the piezo signal line pairs is the ground line Pg, the crosstalk from the ground line Pg is small. Therefore, as in the two layout examples on the lower side of FIG. 9, the ground line and the contact sensor signal transmission line pair SS can be allowed to be adjacent in design. Also in the layout, the heater signal transmission line H is wired between the read signal transmission line pair RR and the piezo signal transmission line pair PPg. If the crosstalk from the piezo signal transmission line P is small, the piezo signal transmission line P and the contact sensor signal line pair SS may be arranged adjacent to each other.

  The current flowing through the piezo signal transmission line pair PP, PPg is small, and it is not necessary to consider heat generation in the design. Therefore, in terms of heat balance, the piezo signal transmission line pair PP, PPg can be regarded as having the same characteristics as the read signal transmission line pair RR and the contact sensor signal line pair SS. Each of the branched signal transmission line bundles includes at least one of the read signal transmission line R, the heater signal transmission line H, and the piezo signal transmission lines P and Pg. The signal wiring layout shown in FIG. 9 is based on the premise that ten signal transmission line bundles are branched into two five signal transmission line bundles. In each layout of FIG. 9, one of the read signal transmission line R, the heater signal transmission line H, and the piezo signal transmission lines P and Pg is included in the right and left half signal transmission lines.

  As mentioned above, although this invention was demonstrated taking preferable embodiment as an example, this invention is not limited to said embodiment. A person skilled in the art can easily change, add, and convert each element of the above-described embodiment within the scope of the present invention. The present invention may be applied to disk drive devices other than HDDs. The signal transmission line bundle is preferably branched in half near the head slider, but a configuration in which the number of signal transmission lines in one bundle is two or more than the number of signal transmission lines in the other bundle is also possible. The present invention can also be applied to an HGA in which both a piezo element and an optical element are mounted.

DESCRIPTION OF SYMBOLS 1 Hard disk drive, 11 Magnetic disk, 12 Base 13 Spindle motor, 15 Head slider, 16 Actuator 17 Rotating shaft, 18 Flexible printed circuit 19 Voice coil motor, 151 Write element, 152 Read element 153 Heater Element, 154 Contact sensor element, 160 Head gimbal assembly 161 Suspension, 162 Arm, 163 Voice coil 164 Signal transmission wiring, 169 Multi-connector tab, 181 Connector IC182 Preamplifier, 611 Gimbal, 612 Load beam 613 Mount plate , 614 tail part, 621 hinge part 641, 642 branched signal transmission line bundle, 643 signal transmission line bundle

Claims (11)

Suspension,
A head slider fixed on the suspension;
A write element, a read element, a heater element and a contact sensor element formed on the head slider;
A signal transmission line bundle comprising a plurality of signal transmission lines arranged side by side for transmitting the signal of the head slider;
The signal transmission line bundle is:
A lead signal transmission line pair consisting of adjacent lead signal transmission lines;
A pair of write signal transmission lines consisting of adjacent write signal transmission lines;
A heater signal transmission line pair;
A contact sensor signal transmission line pair, and
The light and signal transmission line pair between the read signal transmission line pair, and at least one heater signal transmission line is a wiring of the heater signal transmission line pair,
Between the contact sensor signal transmission line pair and the write signal transmission line pair, at least one heater signal transmission line of the heater signal transmission line pair are wired,
The signal transmission line bundle branches into a first branch signal transmission line bundle and a second branch signal transmission line bundle,
Each of the first branch signal transmission line bundle and the second branch signal transmission line bundle includes at least one of the lead signal transmission line and the contact sensor signal transmission line,
Head gimbal assembly. Suspension,
A head slider fixed on the suspension;
A write element, a read element, a heater element, a contact sensor element, and an optical element that generates heat-assisted recording light formed on the head slider;
A signal transmission line bundle comprising a plurality of signal transmission lines arranged to transmit the signal of the head slider,
The signal transmission line bundle is:
A lead signal transmission line pair consisting of adjacent lead signal transmission lines;
A pair of write signal transmission lines consisting of adjacent write signal transmission lines;
A heater signal transmission line pair;
An optical element signal transmission line pair;
A contact sensor signal transmission line pair, and
Between the write signal transmission line pair and the read signal transmission line pair, at least one signal transmission line of the heater signal transmission line pair and the optical element signal transmission line pair is wired.
Between the light signal transmission line pair and the contact sensor signal transmission line pair, at least one signal transmission line of the heater signal transmission line pair and the optical element signal transmission line pair is wired .
The signal transmission line bundle branches into a first branch signal transmission line bundle and a second branch signal transmission line bundle,
Each of the first branch signal transmission line bundle and the second branch signal transmission line bundle includes at least one of the lead signal transmission line and the contact sensor signal transmission line.
Head gimbal assembly. The contact sensor signal transmission line pair is composed of adjacent contact sensor signal transmission lines ,
The head gimbal assembly according to claim 1 or 2. The contact sensor signal transmission line pair is composed of adjacent contact sensor signal transmission lines,
The first branch signal transmission line bundle includes one of the contact sensor signal transmission lines,
The second branch signal transmission line bundle includes the other of the contact sensor signal transmission lines,
The connection pads of the plurality of signal transmission lines are arranged on the end surface of the head slider, and the two connection pads of the contact sensor element are arranged at both ends.
The head gimbal assembly according to claim 1 or 2. Wherein each of the first branch signal Den Ochsen flux and the second branch signals Den Ochsen bundle, and a signal transmission line of half of the signal Den Ochsen bundle,
The head gimbal assembly according to claim 4. The signal transmission line bundle includes a pair of piezoelectric signal transmission lines for transmitting a signal of a piezoelectric element,
Between the read signal transmission line pair and the piezoelectric signal transmission line pair, at least one heater signal transmission line of the heater signal transmission line pair are wired,
The head gimbal assembly according to claim 1. Before SL Each of the first branch signal Den Ochsen flux and the second branch signals Den Ochsen bundle, the lead signal transmission line, the contact sensor signal transmission line, at least one of said piezoelectric signal transmission line including,
The head gimbal assembly according to claim 6. The connection pads of the plurality of signal transmission lines are arranged on the end surface of the head slider, and the two connection pads of the contact sensor element are arranged at both ends.
The head gimbal assembly according to claim 1, 2 or 3. One heater signal transmission line of the heater signal transmission line pair is a ground line,
The ground line is adjacent to the lead signal transmission line pair;
The head gimbal assembly according to claim 1. One signal transmission line of the heater signal transmission line pair and / or one signal transmission line of the optical element signal transmission line pair is a ground line,
The ground line is adjacent to the lead signal transmission line pair;
The head gimbal assembly according to claim 2. Before SL Each of the first branch signal Den Ochsen flux and the second branch signals Den Ochsen bundle, which consists of a signal transmission line of half of the signal Den Ochsen bundle,
Wherein each of the first branch signal Den Ochsen flux and the second branch signals Den Ochsen bundle includes at least one of said read signal transmission line and the contact sensor signal transmission lines,
The connection pads of the plurality of signal transmission lines are arranged on the end surface of the head slider, and the two connection pads of the contact sensor element are arranged at both ends.
The head gimbal assembly according to claim 1, 2 or 3.

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