Classifications

• • H—ELECTRICITY
  • H01—ELECTRIC ELEMENTS
  • H01R—ELECTRICALLY-CONDUCTIVE CONNECTIONS; STRUCTURAL ASSOCIATIONS OF A PLURALITY OF MUTUALLY-INSULATED ELECTRICAL CONNECTING ELEMENTS; COUPLING DEVICES; CURRENT COLLECTORS
  • H01R35/00—Flexible or turnable line connectors, i.e. the rotation angle being limited
  • H01R35/02—Flexible line connectors without frictional contact members
  • H01R35/025—Flexible line connectors without frictional contact members having a flexible conductor wound around a rotation axis

Definitions

• the present invention pertains to the field of automation technology. It relates to an apparatus for manipulating objects, in particular semiconductor chips, and to a flexible flat cable, in accordance with the preamble of the independent patent claims.
• slip rings are in general very reliable for configurations where an orientation of a rotation remains constant over a large number of revolutions, and allow for very large numbers of revolutions, they often fail after a relatively low number of cycles when used in a configuration in which a rotation direction of a ro- table part is always reversed after a cycle of a few, typically around 3 to 7 revolutions.
• the situation becomes particularly problematic in a swivel mode, in which the rotation direction is always reversed before a full revolution of 360° is carried out.
• Such a swivel mode is for example used in die bonders for picking chips from a semiconductor wafer by means of a pick tool and handing them over to a place tool at a location above the wafer, as described in International Application Publication No. WO 2007/118511 Al, which is hereby incorporated by reference in its entirety.
• FIG. 1 For configurations where the rotation direction always reverses after a limited number of revolutions, a configuration as shown in Fig. 1 is often used.
• a flexible flat cable 5 - shown from its side - is fixed to a first body section 10 of a machine by means of a first fixation 101, and fixed to a second body section 11 by means of a second fixation 111.
• the second body part 11 is capable of rotating about a rotational axis perpendicular to the plane of Fig. 1, with the second fixation 111 located on the rotational axis.
• an apparatus for manipulating objects comprises: a first body section comprising a first plurality of electrical terminals; a second body section comprising a second plurality of electrical terminals, and configured to swivel relative to the first body section around a swivel axis; a flexible flat cable for facilitating an electric connection between the first plurality of electrical terminals and the second plurality of electrical terminals, said flexible flat cable being configured for sustaining repeated bending around at least one bending axis; and means for fixing the flexible flat cable with the bending axis or the bending axes essentially parallel to the swivel axis, said means for fixing comprising a first fixation mounted to the first body portion, and a second fixation mounted to the second body portion.
• a flexible flat cable having a plurality of isolated lines comprises: a first termination at a first end of said flexible cable, said first termination comprising a first number of electrical contacts, each connected to at least one isolated line; a second termination at a second end of said flexible cable, said second termination comprising a second number of electrical contacts, each connected to at least one isolated line; a first holder fixed to the flexible cable and configured to be attached to a first external fixation; and a second holder fixed to the flexible cable and configured to be attached to a second external fixation.
• Fig. 1 shows a schematic of an apparatus according to the state of the art.
• Fig. 2 shows a perspective view of an apparatus in accordance with an exemplary embodiment of the present invention.
• Fig. 3 shows another perspective view of the apparatus shown in Fig. 2, with some parts removed for better visibility.
• Fig. 4 shows a schematic of an apparatus in accordance with an exemplary embodiment of the present invention.
• Fig. 5 shows another schematic of an apparatus in accordance with an exemplary embodiment of the present invention.
• Fig. 6 shows a schematic of a flexible flat cable in accordance with an exemplary embodiment of the present invention.
• Fig. 2 shows a perspective view of machine parts from a die bonder.
• a swivel range is defined as
• the second body section 11 may e.g. comprise a pick tool not shown in the drawing for picking dies from a wafer table.
• a bearing unit 109 contains a bearing for the second body section 11 and a drive unit (not visible in the drawing) for swivelling said second body section 11.
• a flexible flat cable 5 comprising a first termination 511 and a second termination 512 is fixed to first fixation 101 provided on the first body section 10 by means of a first holder 521 and to a second fixation 111 provided on the second body section 11 by means of a second holder 522.
• a damper 108 made of foamed material is provided in a vicinity of the flexible flat cable 5 to dampen lateral movements that an upper section of the flexible flat cable 5 may exhibit in operation.
• the first fixation 101 is mounted on a leaf spring 107 to allow for a small movement of said first fixation 101 in a direction towards the swivel axis.
• This permits to choose a length / of the flexible flat cable between the first and second fixation 101, 111 sufficiently short so that a corresponding section of the cable forms a straight line when the second body section 11 is at an angular position ⁇ 0, which corresponds to the angular position shown in Fig. 2.
• the first and second fixation form an essentially straight line intersected by the swivel axis, and such that length / of the flexible flat 5 cable between the first and second fixation 101, 111 runs along said straigth line.
• / is chosen such that leaf spring 107 is under tension for angular positions ⁇ ⁇ 0, and is relaxed for angular positions with
• a flexible tube 9 is fixed to the flexible flat cable 5 by means of clamps
• the second body section 11 comprises a cable mounting section 110 on which the second fixation 111 is provided.
• Two cable guiding blocks 115 are provided on the cable mounting section 110.
• Each cable guiding block 115 has a curved surface 1151 having a curvature redius r guide that equals at least approximately a minimum bending radius r bend , mm of the flexible flat cable 5, preferably satisfying 0.9 ''bend, mm ⁇ ''guide ⁇ 1.5 r ben d, mm-
• the minimum bending radius r ben d, mm is commonly specified by a vendor and/or manufacturer of the flexible flat cable 5.
• the cable may be bent repeatedly without failure for a given number of bending cycles.
• the flexible tube 9 is also guided by the guiding blocks 115 to prevent that kinks form in said flexible tube 9 as a result of the swivel movement.
• Slits 11511 formed in the curved surfaces 1151 allow for usage of flexible tubes having a diameter larger than a thickness of the flexible flat cable 5 while permitting the guiding blocks 115 to be positioned directly adjacent to said flexible flat cable 5, thus preventing that the cable may be forced into shapes comprising bending radii smaller than r bend , mm -
• one or more spikes or poles may also be provided for the same purpose.
• FIG. 3 shows another perspective view of the machine parts shown in
• a hollow axis 117 acts as support for cable mounting section 110, and also for the pick tool (not shown in Fig. 3).
• a cable 8 having a plurality of lines extends from the cable mounting section 110 to the pick tool through the hollow axis 117.
• the lines are preferably formed by wires, braids or strands electrically insulated with respect to one another.
• the flexible tube 9 also extents through the hollow axis 117 to allow for the pick tool to be provided with vacuum and/or pressurized air.
• FIG. 4 shows a schematic of an exemplary embodiment of the inventive apparatus, illustrating how angular position ⁇ and a distance d between the second fixation 522 and the swivel axis S are measured.
• Fig. 5 shows another schematic of an exemplary embodiment of the inventive apparatus. If parameters, in particular d and /, are properly chosen, the flexible flat cable does not come into contact with the cable guiding blocks 115 as long as the second body section 11 is not swivelling, independent of the angular position ⁇ . Under such conditions, a shape assumed by the flexible flat cable 5 is governed by an equilibrium state, which in turn depends primarily on a flexibility and a weight of the flexible flat cable 5, the angular position ⁇ and an orientation of the first body section 10. Only when the second body section 11 swivels with high frequency does the flexible flat cable 5 touch the cable guiding blocks 115 at angular positions ⁇ ⁇ 0. [0019] Fig. 6 shows a flexible flat cable 5 comprising a plurality of lines 50.
• the lines are preferably formed by wires, braids or strands electrically insulated with respect to one another.
• a first termination 511 at a first end of said flexible cable comprises a first number N 1 of electrical contacts, each connected to at least one of the plurality of lines 50.
• a second termination 512 at a second end of said flexible cable comprises a second number /V 2 of electrical contacts, each connected to at least one of the plurality of lines 50.
• First and second outer lines 501 and 502 are connected to one another at the second end and are used for monitoring a state of the flexible flat cable 5.
• outer lines of flexible flat cables are generally the first to fail, e.g. by breaking, due to fatigue after repeated bending cycles, an indication when to replace the flexible flat cable 5 may thus be obtained when a electrical circuit between contacts of the first termination 511 connected to the first outer line 501 and the second outer line 502 is interrupted.
• N 2 ⁇ N 1 in such a configuration.

Landscapes

• Electric Cable Arrangement Between Relatively Moving Parts (AREA)
• Insertion, Bundling And Securing Of Wires For Electric Apparatuses (AREA)

Priority Applications (2)

Applications Claiming Priority (2)

Publications (1)

Family

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Family Applications (1)

Country Status (3)

Cited By (1)

Citations (8)

• 2009
  • 2009-08-31 EP EP09782385A patent/EP2335329A1/en not_active Withdrawn
  • 2009-08-31 WO PCT/EP2009/061194 patent/WO2010026123A1/en active Application Filing
  • 2009-08-31 CN CN2009801331545A patent/CN102204036A/zh active Pending

Patent Citations (8)

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