Method for manufacturing a flexible printed circuit board and corresponding support arrangement

Abstract

A support arrangement (2) for fixing a substrate (4) of a flexible printed circuit board / FPCB (6) in a manufacturing process of the FPCB (6) is provided. The support arrangement (2) comprises a flat and rigid frame (10) surrounding an opening (16) which is open to both sides of the frame (10). The support arrangement (2) further comprises at least three suspension elements (18, 20, 22, 24, 64, 66, 68, 70, 74) attached to the frame (10) and distributed around an edge (30) of the opening (16), for temporarily fixing the substrate (4) in the opening (16) of the frame (10). A first suspension element (18) is fixedly attached to the frame (10) at at least two points. All further suspension elements (20, 22, 24) are resiliently slidably attached to the frame (10). The support arrangement (2) may further comprise at least one carrier plate (26) that can be assembled with the frame (10) such that a support region (50) of the carrier plate (26) is aligned with the opening (16) of the frame (10). In a method of manufacturing the FPCB (6), the substrate (4) of the FPCB (6) to be assembled is fixed in said frame (10). The frame (10), together with the substrate (4) fixed therein, is assembled with the carrier plate (26) such that the substrate (4) rests on the support region (50) of the carrier plate (26). A process step in the manufacture of the FPCB (6) to be assembled is then carried out on the substrate (4) fixed in the frame (10) and resting on the support region (50) of the carrier plate (26).

Description

[0001] DESCRIPTION

[0002] Method for manufacturing a flexible printed circuit board and corresponding support arrangement

[0003] The invention relates to a method for manufacturing a flexible printed circuit board (also referred to as “FPCB” or “flexprint”) and to a support arrangement for use in the method. The term “flexible printed circuit board” (FPCB) is used here and in the following to refer to a ready-made substrate provided with conductor tracks and electronic components assembled thereon to form an electronic circuit which is optionally encapsulated in a potting compound or a housing.

[0004] The manufacture of an FPCB typically comprises a multitude of process steps, often including

[0005] - one or more screening steps in which a solder and / or flux is applied to a substrate of the FPCB;

[0006] - one or more pick-and-place steps in which surface mounted electronic components (“surface mounted devices” or “SMD”) are placed on one of the surfaces of the substrate; in successive pick-and-place steps, often both surfaces of the substrate are equipped with components;

[0007] - one or more heating steps, in particular reflow soldering steps, in which the components previously placed on one of the surfaces of the substrate are permanently fixed and electrically conductively connected to conductive tracks on the substrate;

[0008] - one or more filling steps in which at least some of the components mounted on the substrate are underfilled with and / or encapsulated in a potting compound; the or each filling step may be followed by a post-processing step in which the potting material is hardened, e.g. by application of heat or UV radiation, or in which the potting compound is otherwise processed; one or more inspection steps in which the partially or fully assembled FPCB is optically (visually) inspected for defects by a person or by automatic image processing;

[0009] - one or more testing steps in which the partially or fully assembled FPCB is subjected to an (electronic and / or mechanical) functional test; and / or

[0010] - one or more depaneling or cutting steps in which one or more individual FPCBs are cut, punched out or broken out from a so-called panel, i.e. a larger substrate on which a several such individual FPCBs are formed.

[0011] Usually, these process steps are carried out at different machines or work stations of a production line. Thus, the partially or fully assembled FPCBs have to be transported between said machines or work stations and have to be temporarily stored several times during manufacture. During at least most of the process steps as well as during transportation and storage, the flexible substrate of the FPCBs to be assembled needs to be supported mechanically to avoid bending of the substrate and, as a result, incorrect placement of components or potting compound, loss of contact of components to the substrate, or other damage.

[0012] In order to provide such support during the manufacturing process, the partially or fully assembled FPCBs are often inserted and fixed in flat or tub-shaped carriers. Such carriers typically have a recess adapted to receive the substrate such that an outer surface of the substrate is aligned (i.e. arranged coplanar) with an outer border region of the carrier. In the bottom of the recess, the carriers are often provided with one or more cavities, e.g. to receive components that had been placed on a bottom side of the substrate in a previous process step.

[0013] Because components, fillings and / or other structures are often added to both sides of the substrate, the substrate is normally flipped once or several times in the course of the manufacturing process. Also, the number of components and other structures arranged to either side of the substrate change during the manufacturing process as an increasing number of components and other structures (such as potting compound) are added. Therefore, the volume occupied or required by the FPCB on each side of the substrate changes in the course of the manufacturing process. As a result, different carriers (differing, e.g., in the cavities provided in the bottom of the respective recess receiving the substrate) have to be used in different steps of the manufacturing process. Therefore, each substrate has to be removed from its old carrier once or several times during the manufacturing process and inserted in anew carrier. Due to the flexibility and sensitivity of the FPCBs under production, the operations of removing the substrate from a carrier and inserting the substrate in a new carrier are difficult to automate. Therefore, these operations are often performed manually, which is counterproductive to the goal of fast and economic manufacturing. Another disadvantage of previous manufacturing processes is that the substrate is very likely to be bent when it is removed from a carrier which implicates a risk of damaging the substrate or the FPCB partially assembled thereon.

[0014] In view of the forgoing, an object of the present invention is to provide solutions allowing for fast and economic manufacture of an FPCB.

[0015] According to the invention, the above object is met by a support arrangement as defined by claim 1 for fixing a substrate of an FPCB to be assembled. The support arrangement is to be used in a manufacturing process of the FPCB. The above-mentioned object is also met, according to the invention, by a method for manufacturing an FPCB as defined by claim 14. Preferred embodiments of the invention are described in the dependent claims and the subsequent description.

[0016] The support arrangement according to the invention comprises a flat and rigid frame that extends in a suspension plane, in which the substrate of the FPCB is to be suspended. The frame has a first side and a second side opposite to the first side and surrounds an opening in which the substrate is to be inserted. Different from carriers as described above that have been used conventionally to support FPCB substrates during manufacture, the frame and the opening formed therein are open to both sides of the frame such that a substrate fixed in the opening of the frame is freely accessible from both sides of the frame.

[0017] In preferred embodiments of the invention, the support arrangement further comprises a plurality of suspension elements (subsequently referred to as “suspensions”) attached to the frame for temporarily fixing the substrate in the opening of the frame. Preferably, the substrate basically extends within the suspension plane when fixed by the suspensions.

[0018] Preferably, the frame and the suspensions are designed to fix the substrate such that the entire substrate is arranged inside the opening; i.e. such that the substrate does not overlap with the frame (as seen in a direction perpendicular to the suspension plane). In particular, the substrate is held in a (small) distance to the edge of the opening. In this case, each of the plurality of suspensions extends into the opening with a free end of this suspension. Thus, both sides of the substrate are accessible in entirety when the substrate is fixed in the frame. Moreover, the substrate can be equally deflected or offset from (i.e. shifted parallelly out ol) or bent out of the suspension plane towards both sides of the frame.

[0019] The free end of each suspension is provided with a coupling contour designed to engage the substrate. In advantageous embodiments, the coupling contour of each of the suspensions is designed to engage a counter-coupling contour of the substrate that may be formed complimentary to the coupling contour. E.g., the coupling contour of the suspension may be designed as a hook, a pin, or a nose; and the counter-coupling contour of the substrate may be designed, e.g., as a hole or lug (which the hook, pin or nose of the suspension may engage). In other embodiments, the coupling contours of the suspensions may be designed to fix the substrate without interacting with a counter-coupling contour of the latter. E.g., the coupling contours may be designed as clips or clamps for gripping the edge of the substrate at an arbitrary position thereof.

[0020] As an alternative to suspensions that protrude into the opening, the frame may be equipped with a plurality the suspension elements that are located outside the opening. In this case, the substrate is attached to the frame such that it overlaps with the frame (as seen in a direction perpendicular to the suspension plane). In particular advantageous embodiments of the invention, the substrate may be provided with lateral extensions (flaps) that are designed to overlap with the frame for fixing the substrate to the frame. Preferably, the comers of the substrate are free from such flaps such the substrate can be deflected or offset from or bent out of the suspension plane towards both sides of the frame, when fixed at the frame, without formation of wrinkles in the substrate. In certain embodiments of the invention, the frame may comprise two separate or folda- bly connected parts which are designed to clamp the substrate between them.

[0021] The frame allows for a significant improvement in the production of an FPCB, as it can fix and support the substrate during the entire manufacture of the FPCB. Clamping the loose and flexible substrate into the frame and removing the substrate from the frame - which operations are complex and difficult to automate - thus have to be carried out only once in the entire manufacturing process of the FPCB. The multiple insertion and removal of the loose, flexible substrate into and from different carriers, which is common to conventional manufacturing processes, is no more necessary when using the support arrangement according to the invention, which saves a considerable amount of work and time in the manufacture of the FPCBs. Due to the free accessibility of the substrate from both sides of the frame, both sides of the substrate can be processed in the course of the manufacturing process, in particular equipped with electronic components, without having to detach the substrate from the frame; rather, the frame can be simply flipped together with the substrate clamped therein. In addition, the fact that the substrate remains clamped in the frame throughout the entire manufacturing process means that it is less bent (and thus less mechanically stressed) than in conventional processes. In particular, the frame allows for safely storing the substrate and the FPCB partially mounted thereon between manufacturing steps. This reduces the risk of the FPCB being damaged during the manufacturing process.

[0022] In preferred embodiments of the invention, the plurality of suspensions comprises at least three suspensions distributed around an edge of the opening of the frame. In order to assure a well-defined position of the substrate in relation to the frame, when the substrate is inserted the frame, the at least three suspensions comprise a first suspension element (“first suspension”) that is fixedly attached to the frame such that the coupling contour of this first suspension is held in an approximately stationary position relative to the frame in the two dimensions of the suspension plane. In other words, the first suspension is attached to the frame such that its coupling contour is not movable relative to the frame in the two dimensions of the suspension plane. In contrast, in preferred embodiments of the invention, all further suspensions of said at least three suspensions are resiliently slidably attached to the frame such that the respective coupling contour of these further suspensions is movable perpendicularly or obliquely relative to an adjacent region of the edge of the opening. In other words, the coupling elements of the further suspensions can be dislocated from their respective resting position against a restoring force directed (perpendicularly or obliquely) towards the edge of the opening. The further suspensions are, thus, designed and operable to stretch or tension the substrate within the opening of the frame, similar to the jumping cloth of a trampoline. In particular, the further suspensions may be spring-loaded.

[0023] In a particularly advantageous embodiment, the plurality of suspensions comprises four suspensions that are distributed relative to each other in a rectangular arrangement around the edge of the opening. Herein, the four suspensions comprise the first suspension element (“first suspension”) as described. Moreover, the four suspensions further comprise a second suspension element (“second suspension”), which is arranged adjacent to the first suspension in the rectangular arrangement of the four suspensions, and which is fixedly or pivotally attached to the frame at one point and is resiliently slidably attached to the frame at another point (e.g. against the restoring force of a spring) such that the coupling contour of said second suspension is movable within the suspension plane in a direction pointing towards the first suspension (more precisely towards the coupling contour of the first suspension). The four suspensions further comprise a third suspension element (“third suspension”), which is arranged diagonally opposite to the first suspension in the rectangular arrangement of the four suspensions, and which is resiliently slidably attached to the frame (e.g. against the restoring force of a spring) such that the coupling contour of said third suspension is movable within the suspension plane in an inclined direction, with respect to adjacent sides of the rectangular arrangement of the four suspension elements. The four suspensions finally comprise a fourth suspension element (“fourth suspension”), which is arranged diagonally opposite to the second suspension in the rectangular arrangement of the four suspensions, and which is resiliently slidably attached to the frame (e.g. against the restoring force of a spring) such that the coupling contour of said fourth suspension is movable within the suspension plane in an inclined direction, with respect to adjacent sides of the rectangular arrangement of the four suspension elements. In this configuration, the first suspension approximately defines a fixed reference point of the substrate’s position in the two dimensions of the suspension plane. The second suspension, by virtue of its fixed connection to the frame, defines a fixed rotational position of the substrate with respect to the frame in the two dimensions of the suspension plane. By virtue of their resiliently slidably coupling to the frame, as defined above, the second suspension, together with the third and fourth suspensions, homogeneously stretch or tension the substrate in the opening of the frame.

[0024] In general, the coupling contour of said third and fourth suspension being movable in an inclined direction means that the direction in which the respective coupling contour can move is at an acute angle (i.e. an angle larger than 0° and smaller than 90°) to the respective adjacent sides of the rectangular arrangement of the four suspension elements.

[0025] Herein, in an embodiment of the invention, the third and fourth suspensions are resili- ently slidably attached to the frame such that their respective coupling contour is movable in a direction pointing towards the respective opposite suspension (more precisely towards the coupling contour of said opposite suspension). Thus, the coupling contour of the third suspension is movable in a direction pointing towards the first suspension (or its coupling contour), and the coupling contour of the fourth suspension is movable in a direction pointing towards the second suspension (or its coupling contour). This embodiment is particularly advantageous (and, thus, preferred) if the four suspension elements are arranged in similar next neighbor distances (i.e. close to a square arrangement).

[0026] In a further embodiment, the third and fourth suspensions are resiliently slidably attached to the frame such that their respective coupling contour is movable in a direction being aligned at an angle of 45° to the respective adjacent sides of the rectangular arrangement of the four suspension elements. This embodiment is particularly advantageous (and, thus, preferred) for elongated rectangular arrangements of the four suspension elements (i.e. if two sides of the rectangular arrangement of the four suspension elements are considerably larger than the remaining two sides). For such elongated arrangements, the 45° orientation of third and fourth suspensions ensures a particularly homogenous distribution of mechanical stress in the substrate when the latter is stretched between the suspensions.

[0027] For elongated rectangular arrangements of the four suspensions, preferably, the first suspension and the second suspension are positioned at a long side of the rectangular arrangement. I.e., the first suspension and the second suspension are positioned in neighboring angles of the rectangular arrangement of the suspensions which angles are connected by a long side of the arrangement. This ensures a particularly precise alignment of the substrate being fixed in the frame with particularly low inaccuracy with respect to rotational misalignment of the substrate.

[0028] Preferably, each of the plurality of suspensions is pivotally attached to the frame or can be bent resiliently in a direction perpendicular to the suspension plane. This allows for slightly lifting (deflecting or offsetting) the substrate out of the suspension plane without removing the substrate from the frame, which is advantageous for some process steps in the manufacturing process of the FPCB. In particular, a small planar displacement (offset) of the substrate surface is beneficial for screening steps, to allow for clearance between scraper and frame when mounted on carrier.

[0029] In order to achieve this effect, the suspensions may be designed as leaf springs. Optionally, to support the capability of each suspension to be pivoted or bent out of the suspension plane, each of the plurality of suspensions is attached to the frame at a distance from the edge of the opening. In this case, preferably, the suspensions are arranged in slots of the frame such that they can be pivoted or elastically bent out of the suspension plane toward both the first side and the second side of the frame.

[0030] In addition to the frame provided with the suspensions, the support arrangement according to the invention may further comprise at least one carrier plate that can be assembled with the frame such that a support region of the carrier plate, being provided for supporting the substrate fixed in the frame, is aligned with the opening of the frame. To this end, the frame may be designed to be placeable on the carrier plate in a well-defined relative position.

[0031] Herein, preferably, the support region of the carrier plate protrudes from a border region of the carrier plate surrounding it such that the support region extends into the opening of the frame or through the opening of the frame in order to lift (deflect or offset) the substrate out of the suspension plane when the carrier plate is assembled with the frame.

[0032] In an advantageous embodiment, the frame is designed such that it can be assembled with the carrier plate in two alternative positions, i.e. in a first position in which the first side of the frame faces the carrier plate and in a second position in which the second side of the frame faces the carrier plate. As an alternative, different carrier plates may be provided to be assembled with the first side of the frame and with the second side of the frame, respectively.

[0033] In order to assure precise alignment of the frame (and the substrate fixed therein) with respect to the carrier plate, preferably, the frame and the carrier plate are provided with corresponding pilot structures. For instance, said pilot structures may comprise a plurality of pilot pins on the carrier plate engaging in corresponding pilot holes of the frame, or a plurality of corresponding pilot holes in both the frame and the carrier plate which may be mutually aligned by separate pilot pins.

[0034] In some embodiments of the invention, the support region of the carrier plate may be provided with at least one cavity providing free space adjacent to the substrate when the frame with the substrate fixed therein is assembled with the carrier plate. The at least one cavity may, e.g., be provided to receive one or more electronic components placed on a bottom side of the substrate.

[0035] In some embodiments, the support arrangement according to the invention comprises a plurality of carrier plates which differ in the configuration of the support region, and which may be used, in exchange with one another, together with the frame. In other words, the frame can be assembled selectively with each of the plurality of carrier plates. In particular, the support arrangement may be designed such that the frame with substrate fixed therein can be successively assembled with different carrier plate in different process steps of a manufacturing process.

[0036] The method of manufacturing an FPCB according to the invention uses the support arrangement according to the invention as previously described. Herein, the various embodiments of the support arrangement described in the foregoing correspond to embodiments of the method. Thus, the disclosure relating to embodiments of the support arrangement and their respective effects and advantages can be transferred to embodiments of the method, and vice versa. In the method, a substrate of the FBCB to be assembled is suspended in the frame of the support arrangement (e.g. by connecting the coupling contours of the suspensions to the counter-coupling contours of the substrate). The frame, together with the substrate fixed therein, is assembled with the carrier plate or one of the plurality of carrier plates of the support arrangement such that the second side of the frame faces the carrier plate and the substrate rests on the support region of the carrier plate. Subsequently, a process step in the manufacture of the FPCB to be assembled is carried out while the substrate is fixed in the frame and rests on the support region of the carrier plate.

[0037] Preferably, the process step is selected from one of

[0038] - a screening step in which a solder and / or flux is applied to the substrate;

[0039] - a placement step (pick-and-place step) in which surface-mounted electronic components are placed on a surface of the substrate;

[0040] - a heating step, in particular a reflow soldering step, in which the components previously placed on the surface of the substrate are permanently fixed and electrically conductively connected to conductor tracks on the substrate;

[0041] - a filling step in which at least some of the components mounted on the substrate are underfilled with a potting compound or embedded in a potting compound;

[0042] - an inspection step in which the partially or fully assembled FPCB is optically (visually) inspected for defects by a person or automatic image processing;

[0043] - a test step in which the partially or fully assembled FPCB is subj ected to a (electronic or mechanical) functional test; and

[0044] - a depaneling step or cutting step in which at least one individual FPCB is cut out, punched out or broken out from the substrate comprising a plurality of such individual FPCBs.

[0045] Preferably, the frame is disassembled from the carrier plate (directly or indirectly) after carrying out the process step and is assembled (again directly or indirectly thereafter) with another carrier plate of the support arrangement, together with the substrate fixed therein. Subsequently, a further process step in the manufacture of the FPCB to be assembled, in particular one the process steps mentioned above, is carried out on the substrate fixed in the frame and resting on the support region of the further carrier plate.

[0046] In preferred embodiments, the frame is flipped together with the substrate fixed therein before connection with the further carrier plate and is assembled with the further carrier plate such that, now, the first side of the frame faces the further carrier plate.

[0047] In at least one further process step, according to embodiments of the invention, the frame with the substrate fixed therein may be used without being assembled with a carrier plate. Especially, for a reflow-soldering step or another heating step, using the frame without a carrier plate may be advantageous in order to lower the heat capacity of the support arrangement and, thus, allow for fast and energy-saving heating and cooling of the substrate.

[0048] Subsequently, embodiments of the present invention will be described in more detail with reference to the accompanying drawings in which

[0049] Fig. 1 shows a perspective, exploded view of a first embodiment of a support arrangement for fixing a substrate of a flexible printed circuit board (FPCB), the support arrangement comprising a frame surrounding an opening in which the substrate is inserted, a plurality of suspension elements for temporarily fixing the substrate in the opening, and a carrier plate with which the frame can be assembled;

[0050] Fig. 2 shows a perspective view of the frame with the suspension elements fixing the substrate in the opening of the frame;

[0051] Fig. 3 shows a plan view to one the suspension elements;

[0052] Fig. 4 shows a cross-section IV-IV (according to Fig. 3) of the frame and the suspension element of Fig. 3;

[0053] Fig. 5 shows a perspective view of the carrier plate; Fig. 6 shows a (fragmentary) perspective, exploded view of a second embodiment of the support arrangement in which the frame comprises two separate frame parts that can be assembled such that the substrate is clamped between said frame parts,

[0054] Fig. 7 shows a (fragmentary) perspective view of the frame according to Fig.

[0055] 6 in which the frame parts are assembled and the substrate clamped between the frame parts,

[0056] Figs. 8 shows a (fragmentary) perspective, exploded view of a third embodiment of the support arrangement in which the frame comprises two separate frame parts that can be assembled such that the substrate is clamped between said frame parts,

[0057] Fig. 9 shows a (fragmentary) perspective view of the frame according to Fig.

[0058] 8 in which the frame parts are assembled and the substrate clamped between the frame parts,

[0059] Figs. 10 shows a (fragmentary) perspective, exploded view of a fourth embodiment of the support arrangement in which the frame comprises two separate frame parts that can be assembled such that the substrate is clamped between said frame parts,

[0060] Fig. 11 shows a (fragmentary) perspective view of the frame according to Fig.

[0061] 10 in which the frame parts are assembled and the substrate clamped between the frame parts, and

[0062] Fig. 12 shows a simplified flow-chart of a method of manufacturing an FPCB in which the support arrangement (in one of the embodiments shown in Figs. 1 to 11) is used for fixing and supporting the substrate of the FPCB.

[0063] Like reference numerals indicate like parts, structures and elements unless otherwise indicated. Fig. 1 shows a support arrangement 2 for fixing a substrate 4 of an FPCB 6 to be assembled. The support arrangement 2 is designed to fix and support the substrate 4 in a manufacturing process of the FPCB 6. As shown in outline in Figs. 1 and 2, the substrate 4 and the FBCB 6 assembled thereon may be a panel containing a plurality of (in particular identical) individual FPCBs 8 manufactured together in a same process.

[0064] The support arrangement 2 comprises a (for example rectangular) flat and rigid frame 10, e.g. made from a steel sheet, that extends in a suspension plane P which is spanned by a (longitudinal) direction x and a lateral direction y. Together with a (vertical) direction z, the directions x and y form a Cartesian (i.e. orthogonal) coordinate system. The frame 10 has a first side 12 and a second side 14 opposite to the first side 12. It surrounds an (for example rectangular) opening 16 in which the substrate 4 is to be inserted.

[0065] In the example shown in Figs. 1 to 5, the support arrangement 2 further comprises four suspension elements (subsequently referred to as “suspensions” 18, 20, 22 and 24) for temporarily fixing (suspending) the substrate 4 in the opening 16 such that the substrate 4 is basically orientated in the suspension plane P. The opening 16 is open to both sides 12, 14 of the frame 10. Thus, the substrate 4 is freely accessible from both sides 12,14 when it is fixed in the opening 16.

[0066] The support arrangement 2 also comprises a carrier plate 26, which may be made, e.g., from cast or machined aluminum, and with which the frame 10 can be assembled (as indicated in Fig. 1 by an arrow 28).

[0067] In Figs. 2 to 4, the frame 10 and the suspensions 18, 20, 22, 24 are shown in more detail. As can be seen here, each of the suspensions 18, 20, 22, 24 is attached to the frame 10, preferably by rivets, with a distance to an edge 30 of the opening 16. From their respective attachment points, the suspensions 18, 20, 22, 24 extend in slots 32 of the frame 10 towards the edge 30 of the opening 16. Each of the suspensions 18, 20, 22, 24 extends into the opening 16, with a free end 34 of the respective suspension 8, 20, 22, 24. At this free end, each of the suspension 8, 20, 22, 24 is provided with a coupling contour which is formed as a hook 36 that engages a counter-coupling contour of the substrate 4 which is formed as a hole 38. The suspensions 18, 20, 22, 24 hold the substrate 4 such that the entire substrate 4 is received inside the opening 16, preferably with a small distance to the edge 30 of the opening 16.

[0068] In the embodiment of Figs. 1 to 5, the four suspensions 18, 20, 22, 24 are distributed relative to each other in a rectangular arrangement around the edge 30 of the opening 16. In fact, each of the four suspensions 18, 20, 22, 24 is attached in one comer of the opening 16.

[0069] The first suspension 18 has an L-shaped body. Both ends of said L-shaped body are fixedly attached to the frame 10 by means of rivets 39 such that the free end 34 of this first suspension 18 (and the hook 36 formed at this free end 34) is held in an approximately stationary position relative to the frame 16 in the directions x and y. The first suspension 18, thus, defines a reference point (approximately fixed in both directions x and y) for positioning the substrate 4 relative to the frame 10.

[0070] The second suspension 20 is arranged adjacent to the first suspension 18. It also has a L- shaped body, one end of which is fixedly or pivotally (within the suspension plane P) attached to the frame 10 whereas the other end of the L-shaped body is slidably attached to the frame 10, loaded by a spring 40 (preferably a helical compression spring) which pulls the suspension 20 outwardly. As a consequence, in relation to the frame 10, the free end 34 of this second suspension 20 (and the hook 36 formed at this free end 34) is fixed in the direction x, but movable in the direction y (that points to the first suspension 18). By virtue of its fixedly attached end, the second suspension 20 defines the rotatory position of the substrate 4 within the suspension plane P, relative to the frame 10. The slidably coupled end the second suspension 20, being loaded by the spring 40, stretches (tensions) the substrate 4 in the direction y.

[0071] Different from the embodiment shown in Figs. 1 and 2 but preferred, especially if the opening 16 has an elongated form, the first suspension 18 and the second suspension 20 may also be arranged at a long side of the opening 16.

[0072] The third suspension 22 has an elongated, rod-like shape. It is arranged diagonally opposite to the first suspension 18, where it is slidably attached to the frame 10 in a diagonal direction (pointing to the first suspension 18). It is loaded by a spring 41 (preferably a helical compression spring) that pulls the suspension 22 outwardly. Similarly, the fourth suspension 24 has an elongated, rod-like shape. It is arranged diagonally opposite to the second suspension 20, where it is slidably attached to the frame 10 in a diagonal direction (pointing to the second suspension 20). It is loaded by a spring 42 (preferably a helical compression spring) that pulls the suspension 24 outwardly. Together, the third and fourth suspensions 22 and 24 stretch (tension) the substrate 4 in the directions x and y.

[0073] Different from the embodiment shown in Figs. 1 and 2 but preferred, especially if the opening 16 has an elongated form, the third suspension 22 and the fourth suspension 24 may also be arranged such that they are slidable in a direction that is aligned at an angle of 45° to the respective adjacent sides of the opening 16.

[0074] As is best seen in Figs. 3 and 4, the L-shaped second suspension 20 comprises two legs 43 and 44 being articulated with each other by means of a hook 45 formed at an inner end of the leg 44 which engages a lug 46 formed at an inner end of the leg 43. Instead of the hook 45 engaging the lug 46, a rivet rotatably connecting the two legs 43 and 44 may be used.

[0075] The leg 44 consists of three T-shaped parts 47a, 47b and 48. Herein, the two identically formed parts 47a and 47b are fixed to both sides of the frame 10 by means of one of the rivets 39 with the horizontal leg of its T-shape (also referred to as “horizontal T-leg” or “roof’) being arranged near to the edge 30 of the opening 16 and the free end of the vertical leg of its T-shape (also referred to as “vertical T-leg” or “trunk”) pointing away from the first suspension 18. The third T-shaped part 48 is arranged in the corresponding slot 32 of the frame 10 with the horizontal T-leg (“roof’) being arranged distantly to the edge 30 of the opening 16 and the free end of the vertical T-leg (“trunk”) pointing towards the first suspension 18 and carrying the hook 45. The parts 47a, 47b and the part 48 pass through the spring 40 from opposite sides with the respective vertical T-legs such that the spring 40 is clamped between the respective horizontal T-legs of the parts 47a,47b and the horizontal T-leg of part 48.

[0076] Whereas the width of the horizontal T-leg of the part 48 is smaller than the corresponding width of the slot 32 (such that the part 48 is entirely received in the slot 32), the horizontal T-legs of the parts 47a and 47b protrude beyond the slot 32 and, thus, overlap with the frame 10 at both sides thereof. The third and fourth suspensions 22 and 24 have the same or a similar structure as the leg 44 of the second suspension 20. In particular, though not explicitly indicated in the figures, they also comprise the parts 47a, 47b and 48 or similar parts.

[0077] The respective bodies of the suspensions 18, 20, 22 and 24 can be elastically bent in the direction z, towards both sides 12 and 14 of the frame 10. They, thus, act as leaf springs and allow the substrate 4 to be lifted (deflected or offset) out of the suspension plane P. However, as a consequence of the horizontal T-legs of the parts 47a, 47b of the suspensions 20, 22, and 24 overlapping with the frame 10, the respective parts 47a and 47b retain the springs 40, 41 and 42 within the corresponding slots 32 (and, thus, within the suspension plane P) when the substrate 4 is deflected (offset) out of the suspension plane P.

[0078] The carrier plate 26 is shown in Fig. 5. As can be best seen in this figure, the carrier plate 26 has central support region 50 that protrudes from a surrounding border region 52 and the shape of which at least approximately corresponds to the shape of the opening 16. When assembled with the frame 10 as shown in Fig. 1, the latter is placed on said border region 52 of the carrier plate 26. Thus, in the assembled state of the frame 10 and the carrier plate 26, the support region 50 is aligned with the opening 16 of the frame 10 and extends into or through said opening 16. The support region 50 thereby rests against the substrate 4 fixed in the frame 10 and slightly deflects (offsets) it out of the suspension plane P, towards the first side 12 of the frame 10.

[0079] In order to avoid unwanted interference of the suspensions 18, 20, 22, 24 with the carrier plate 26, the border region 52 of the carrier plate 26 is provided with recesses 54, in which the suspensions 18, 20, 22, 24 may be received when the frame 10 is placed on the carrier plate 26. Moreover, to the same effect, the support region 50 is provided with beveled comers.

[0080] Moreover, as shown in outline in Fig. 5, the support region 50 of the carrier plate 26 may be provided with one or more cavities 56, e.g., to receive electronic components placed on a bottom side of the substrate 4. In order to assure precise alignment of the frame 10 with the carrier plate 26, both the frame 10 and the carrier plate 26 are provided with matching pilot holes 58 in which an external pilot pin (not shown) can be inserted.

[0081] In an advantageous embodiment, the frame 10 is designed such that it can be assembled with the carrier plate 26 in two alternative positions. In a first position shown in Fig. 1 the first side 12 of the frame 10 faces away from the carrier plate 26 while the second side 14 faces the carrier plate 26. In a second position, the second side 14 of the frame 10 faces away from the carrier plate 26 while the first side 12 faces the carrier plate 26. As an alternative, the support arrangement 2 may comprise different carrier plates 26 to be assembled with the first side 12 and the second side 14 of the frame 10, respectively. In particular, such different carrier plates 26 may differ in the height of the support region 50 and / or the configuration (i.e. shape, number, size and / or depth) of the cavities 56 formed therein.

[0082] The Figs. 6 and 7 show a second embodiment of the support arrangement 2 in which the frame 10 comprises two separate frame parts 60, 62 that can be assembled such that the substrate is clamped between said frame parts 60, 62. In fact, the Figs. 6 and 7 show a fragment of the frame 10 only. A right comer of the frame 10 that is formed identically to the other comers, is not shown in the Figs. 6 and 7.

[0083] The frame parts 60, 62 have congruent shapes, wherein both frame parts form an entire frame surrounding the opening 16. In the embodiment of Fig. 6 and 7, the support arrangement 2 has four suspensions 64, 66, 68, 70 that are located in the comers of the frame 10. Each of the suspensions 64, 66, 68 and 70 is formed by two arms 72, one of which is attached to the frame part 60 while the other one is attached to the frame part 62. Herein, each arm 72 is formed as a monolithic part of the respective frame part 60 and 62, respectively, by cutting the arm 72 free from the respective frame part 60, 62. Each arm 72 is connected monolithically to the respective frame part 60, 62, at a fixed end of the arm 72, and protmdes into the opening 16 with a free end. All arms 72 point to a center of the opening 16.

[0084] In order to fix the substrate 4 to the frame 10, the two frame parts 60, 62 are separated from each other. The substrate 4 is then positioned on the frame part 62 such that the comers of the substrate 4 overlap with the free ends of the suspension 64, 66, 68, 70. Subsequently, the frame part 60 is assembled with the frame part 62 such that both frame parts 60, 62 overlap entirely and that the substrate 4 is clamped between the free ends of each pair of arms 72. In the assembled state of the frame parts 60, 62 (shown in Fig. 7), each pair of arms 72 grips a corresponding comer of the substrate 4 like a forceps; said pair of arms 72 thus forms one of the suspensions 64, 66, 68, 70.

[0085] In order to more securely hold the substrate 4, the free end of each arm 72 of the frame part 62 may be equipped with a coupling contour that may be formed, e.g. as a hook or a pin protruding in direction z. In this embodiment, counter-coupling contours (holes) are formed in the comers of the substrate 4. Further holes may be provided in the free ends of the arms 72 of the frame part 60. In assembled state of the frame 10, the pins may protrude through the holes provided in the substrate 4 and the arms 72 of the frame part 60. Each of the suspensions 64, 66, 68, 70 can be equally bent out of the suspension plane P to both sides 12, 14 of the frame 10.

[0086] The Figs. 8 and 9 show a third embodiment of the support arrangement 2 in which the frame 10 comprises the two separate frame parts 60, 62 as described above for the second embodiment. However, different from the first and second embodiment, the frame 10 according to Figs. 8 and 9 is not equipped with suspensions that protrude into the opening and can be bent out of the suspension plane P. Instead, the support arrangement 2 according to Figs. 8 and 9 has a plurality of suspensions 74 that are distributed around the four sides of the (rectangular) opening 16 (e.g. six suspensions 74 on each side of the opening 16). The suspensions 74 are formed as hooks or pins that are attached to the frame part 62, outside the opening 16. The hook- or pin-shaped suspensions 74 protrude in direction z from the frame part 62 and act as coupling contours to interact the substrate 4. Preferably, the frame part 60 is equipped with holes through which the suspensions 74 protrude when the frame part 60 is attached to the frame part 62.

[0087] Here, the substrate 4 is provided with lateral extensions (flaps 76) that overlap with the frame 10 (as seen in direction z) when the substrate 4 is attached to the frame 10. The flaps 76 are provided with counter-coupling contours (holes) that engage the suspensions 74 of the frame 10. In assembled state, the substrate 4 is suspended in the opening 16 such as a jumping cloth of a trampoline or a drum head. It, thus, can be bent out of the suspension plane P to both sides thereof. In order to prevent the substrate 4 from forming wrinkles when bent out of the suspension plane P, the comers of the substrate 4 are free from flaps 76. Optionally, the flaps 76 may be separated from a main body of the substrate 4 by one or more lines of perforations 77 to support bending and stretching of the substrate 4 in this region. In an advantageous embodiment, the perforations 77 may be realized as one or more lines of elongated slits. In order to further support bending and stretching of the substrate 4, the slits of different lines of perforations 77 may be offset with respect to each other, as shown in Figs. 8 and 9.

[0088] The Figs. 10 and 11 show a fourth embodiment of the support arrangement 2 in which the frame 10 comprises the two separate frame parts 60, 62 as described above for the third embodiment. However, different from the latter, the frame 10 according to Figs. 10 and 11 has an opening 16 with beveled comers 78. The frame 10 according to Figs. 10 and 11 is equipped with four suspensions 74 similar to those of the third embodiment. However, in the example of Figs. 10 and 11, the suspensions 74 are arranged in beveled comers 78 only, i.e. one of the suspensions 74 in each comer 78 of the opening. As in the case of third embodiment, the frame part 60 may be equipped with holes through which the suspensions 74 protrude when the frame part 60 is attached to the frame part 62.

[0089] Preferably, the substrate 4 is designed such that it overlaps with the frame 10 in the beveled comers 78 only, when it is fixed to the frame 10. The comers of the substrate may be provided with counter-coupling contours (holes) that engage with the suspensions 74 of the frame 10.

[0090] Fig. 12 shows an exemplary embodiment of a method of manufacturing an FPCB 6 in which the support arrangement 2 (in any of the embodiments shown in Figs. 1 to 11) is used.

[0091] In a first step 100 of said method, an empty (i.e. not yet equipped) substrate 4 is fixed in the frame 10, e.g. by hooking the substrate 4, with the holes 38 thereof, on the hooks 36 on the free ends 34 of the suspensions 18, 20, 22 and 24. In a subsequent step 102, the frame 10 with substrate 4 fixed therein is assembled with a first carrier plate 26 such that the first side 12 of the frame 10 faces away from the first carrier plate 26.

[0092] In a subsequent step 104 (screening step), a first side of the substrate 4 fixed in the frame 10 and supported by the first carrier plate 26 is subjected to screening, i.e. a solder and / or flux is applied to selected points or regions of the substrate 4 using an aperture mask through with the solder and / or flux is applied. In order to allow precise application of the solder and / or flux, the support region 50 of the first carrier plate 26 is designed to lift (deflect or offset) the substrate 4 out of the suspension plane P such that the substrate 4 is not surpassed by any structure of the support arrangement 2, as seen in the direction z. This allows for tightly pressing the entire surface of the substrate 4 against the aperture mask.

[0093] In a subsequent step 106 (placement step or pick-and-place step), surface-mounted electronic components are placed on the first side of the substrate 4 fixed in the frame 10 and supported by the first carrier plate 26. The thus equipped first side of the substrate 4 may then be inspected for defects in a subsequent inspection step (not shown), either visually by a person or by electronic image processing.

[0094] In a subsequent step 108, the frame 10 with substrate 4 fixed thereon is disassembled from the first carrier plate 26.

[0095] In a subsequent step 110 (soldering step), the substrate 4 fixed in the frame 10 is heated in an oven such that the components that had been placed on the first side of the substrate 4 are permanently fixed and conductively connected to conductive traces in substrate 4 by reflow soldering. Preferably, no carrier plate 26 is used in this step 110. However, in an alternative embodiment, the order of the steps 108 and 110 may be reversed. Thus, the soldering step 110 may be performed with the frame 10 being assembled with the first carrier plate 26, and the substrate 4 resting on the support region 50 of this carrier plate 26.

[0096] In steps 112 to 120, the steps 102 to 110 are repeated for the second side of the substrate

[0097] 4. Thus, in step 112, the frame 10 with the substrate 4 attached thereon is flipped and assembled with a second carrier plate 26 such that the second side 14 of the frame 10 faces away from the second carrier plate 26. In subsequent steps, the second side of the substrate 4 is subjected to the screening as described above (step 114) and electronic components are placed on the second side of the substrate (step 116). Again, the placement of the components may be checked for defects in a subsequent inspection step (not shown). The frame 10 with the substrate 4 fixed thereon is then disassembled from the second carrier plate 26 (step 118) and made subject to soldering (step 120) to permanently fix and conductively connect the components to conductive traces on the substrate 4. As in the case of the steps 108 and 110, the order of the steps 118 and 120 may be reversed.

[0098] In a subsequent step 122, the frame 10 with the substrate 4 attached thereon is flipped again and assembled with a third carrier plate 26 such that the first side 14 of the frame 10 faces away from the third carrier plate 26.

[0099] In a subsequent step 124, the components mounted on the first side of the substrate 4 are underfilled with a potting compound.

[0100] In a subsequent step 126, the frame 10 with substrate 4 fixed thereon is disassembled from the third carrier plate 26.

[0101] In a subsequent step 128 (post-processing or hardening step), the substrate 4 fixed on the frame 10 is heated in an oven in order to harden the potting compound applied to the first side of the substrate 4. Preferably, no carrier plate 26 is used in this step 128. However, in an alternative embodiment, the order of the steps 126 and 128 may be reversed. Thus, the hardening step 128 may be performed with the frame 10 being assembled with the third carrier plate 27, and the substrate 4 resting on the support region 50 of this third carrier plate 26.

[0102] In steps 130 to 134, the steps 122 to 128 are repeated for the second side of the substrate 4. Thus, in step 130, the frame 10 with the substrate 4 attached thereon is flipped again and assembled with a fourth carrier plate 26 such that the second side 14 of the frame 10 faces away from the fourth carrier plate 26. Then, the components mounted on the second side of the substrate 4 are underfilled with a potting compound (step 132), the frame 10 with substrate 4 fixed thereon is disassembled from the fourth carrier plate 26, and the substrate 4 fixed on the frame 10 is heated in an oven in order to harden the potting compound applied to the second side of the substrate 4, to thereby finish the FPCB 6, i.e. the panel of individual FPCBs 8. As in the case of the steps 126 and 128, the order of the steps 132 and 134 may be reversed.

[0103] In a subsequent step 136, the frame 10 with the substrate 4 attached thereon is flipped again and assembled with a fifth carrier plate 26 such that the first side 14 of the frame 10 faces away from the fifth carrier plate 26.

[0104] In a subsequent step 138 (test step), the FBCB 6, i.e. the electronic circuits formed by the components placed on the first and second side of the substrate 4 are subjected to an (electronic) functional test. Subsequently, the first side of the substrate 4 and parts of the FPCB 6 mounted thereon are inspected for defects (step 140), either visually by a person or by electronic image processing.

[0105] In a subsequent step 142, the frame 10 with the substrate 4 and the FPCB 6 fixed thereon is disassembled from the fifth carrier plate 26. Optionally, in an alternative embodiment of the method, different carrier plates 26 may be used in the steps 138 and 140.

[0106] In steps 144 to 148, the steps 136, 140 and 142 are repeated for the second side of the substrate 4 and the FPCB 6. Thus, the frame 10 with the substrate 4 attached thereon is flipped again and assembled with a sixth carrier plate 26 such that the second side 14 of the frame 10 faces away from the sixth carrier plate 26. Then the second side of the substrate 4 and the parts of the FPCB 6 mounted thereon are inspected for defects (step 146), either visually by a person or by electronic image processing, and the frame 10 with the substrate 4 and the FPCB 6 fixed thereon is disassembled from the sixth carrier plate 26 (step 148).

[0107] In a subsequent step 150, the frame 10 with the substrate 4 attached thereon is flipped again and assembled with a seventh carrier plate 26 such that the first side 14 of the frame 10 faces away from the seventh carrier plate 26.

[0108] In a subsequent step 152 (depaneling step or cutting step), the individual FPCBs 8 are cut from the substrate 4, preferably using laser cutting. In finals step 154 and 156, the frame 10 is disassembled from the seventh carrier plate 26 (step 154) and the remains of the substrate 4 (i.e. the waste material after depaneling) is removed from the frame 10 (step 156).

[0109] As is apparent from the above, the operation of fixing the loose and flexible substrate 4 to the support arrangement 2 (step 100 of the method shown in Fig. 12), which is complex and thus difficult to automate, is performed only once in the entire manufacturing process. Advantageously, this step is performed at the beginning of the process, before the electronic components and potting compound are applied the substrate 4. Therefore, the substrate 4 can be fixed to the frame 6 without any risk of damaging the partially or fully assembled FPCB 6.

[0110] The seven different carrier plates 26 used in the method according to Fig. 12 differ from each other in the configuration of their respective support region 50. In particular, the number, shape, size and depth of the cavities 56 provided in the respective support region 50 differs to adapt to the growing structure of the FPCB 6 under construction.

[0111] Itemized embodiments of the invention:

[0112] 1. A support arrangement for fixing a substrate of a flexible printed circuit board to be assembled in a manufacturing process of the flexible printed circuit board, the support arrangement comprising a flat and rigid frame extending in a suspension plane, said frame having a first side and a second side opposite to the first side and surrounding an opening in which the substrate is to be inserted; wherein the frame and the opening formed therein are open to both sides of the frame such that a substrate fixed in the opening of the frame is freely accessible from both sides of the frame.

[0113] 2. The support arrangement according to item 1, comprising a plurality of suspension elements for temporarily fixing the substrate in the opening of the frame, each of the plurality of suspension elements being attached to the frame.

[0114] 3. The support arrangement according to item 2, wherein each of the suspension elements protrudes into the opening with a free end, said free end being provided with a coupling contour to engage the substrate, in particular a counter-coupling contour thereof.

[0115] 4. The support arrangement according to item 2 or 3,

[0116] - wherein the plurality of suspension elements comprises at least three suspension elements distributed around an edge of the opening of the frame,

[0117] - wherein the at least three suspension elements comprise a first suspension element fixedly attached to the frame at at least two points such that a coupling contour of this first suspension element is held in a stationary position relative to the frame within the suspension plane, and

[0118] - wherein all further suspension elements are resiliently slidably attached to the frame such that a respective coupling contour of these further suspension elements is movable perpendicularly or obliquely relative to an adjacent region of the edge of the opening.

[0119] 5. The support arrangement according to items 2 or 4, wherein the plurality of suspension elements comprise four suspension elements distributed relative to each other in a rectangular arrangement around the edge of the opening, the four suspension elements comprising.

[0120] - a first suspension element fixedly attached to the frame at at least two points such that a coupling contour of this first suspension element is held in a stationary position relative to the frame within the suspension plane,

[0121] - a second suspension element,

[0122] — which is arranged adjacent to the first suspension element in the rectangular arrangement of the four suspension elements, and

[0123] — which is fixedly or pivotally attached to the frame at one point and is resili- ently slidably attached to the frame at another point such that a coupling contour of said second suspension element is movable within the suspension plane in a direction pointing towards the first suspension element,

[0124] - a third suspension element,

[0125] — which is arranged diagonally opposite to the first suspension element in the rectangular arrangement of the four suspension elements, and

[0126] — which is resiliently slidably attached to the frame such that a coupling contour of said third suspension element is movable within the suspension plane in a direction pointing towards the first suspension element, and

[0127] - a fourth suspension element,

[0128] — which is arranged diagonally opposite to the second suspension element in the rectangular arrangement of the four suspension elements, and

[0129] — which is resiliently slidably attached to the frame such that a coupling contour of said fourth suspension element is movable within the suspension plane in a direction pointing towards the second suspension element.

[0130] 6. The support arrangement according to any one of items 2 to 5, wherein each of the plurality of suspension elements is pivotally or resiliently bendably attached to the frame in a direction perpendicular to the suspension plane.

[0131] 7. The support arrangement according to items 6, wherein each of the plurality of suspension elements is attached to the frame at a distance from the edge of the opening, and wherein the suspension elements are arranged in slots of the frame such that they can be pivoted or elastically bent out of said suspension plane towards both the first side and the second side of the frame.

[0132] 8. The support arrangement according to any one of items 1 to 7, further comprising at least one carrier plate that can be assembled with the frame such that a support region of the carrier plate for supporting the substrate fixed in the frame is aligned with the opening of the frame.

[0133] 9. The support arrangement according to item 8, wherein the support region of the carrier plate protrudes from a border region of the carrier plate surrounding it, such that the support region extends into the opening of the frame or through the opening of the frame for deflection of the substrate out of the suspension plane when the carrier plate is assembled with the frame.

[0134] 10. The support arrangement according to any one of items 8 or 9, wherein the frame can be assembled with the carrier plate in two alternative positions such that either the first side or the second side of the frame faces the carrier plate.

[0135] 11. The support arrangement according to any one of items 8 to 10, wherein the frame and the carrier plate are provided with corresponding pilot structures for aligning the frame with the carrier plate.

[0136] 12. The support arrangement according to any one of items 8 to 11, wherein the support region of the carrier plate is provided with at least one cavity providing free space adjacent to the substrate when the frame with the substrate fixed therein is assembled with the carrier plate.

[0137] 13. The support arrangement according to any one of items 8 to 12, comprising a plurality of carrier plates which differ in the configuration of the support region, wherein the frame can be assembled selectively with each of the plurality of carrier plates.

[0138] 14. A method of manufacturing a flexible printed circuit board using a support arrangement according to any one of items 8 to 13, - wherein a substrate of the flexible printed circuit board to be assembled is fixed in the frame of the support arrangement;

[0139] - wherein the frame together with the substrate fixed therein is assembled with the carrier plate or one of a plurality of carrier plates of the support arrangement such that the second side of the frame faces the carrier plate and the substrate rests on the support region of the carrier plate; and

[0140] - wherein a process step in the manufacture of the flexible printed circuit board to be assembled is carried out on the substrate fixed in the frame and resting on the support region of the carrier plate.

[0141] 15. The method according to item 14, wherein the process step is selected from one of

[0142] - a screening step in which a solder and / or flux is applied to the substrate;

[0143] - a placement step in which surface-mounted electronic components are placed on a surface of the substrate;

[0144] - a heating step, in particular a soldering step, in which components previously placed on the surface of the substrate are electrically conductively connected to conductor tracks on the substrate;

[0145] - a filling step in which at least some of the components mounted on the substrate are underfilled with a potting compound or embedded in a potting compound;

[0146] - an inspection step in which the partially or fully assembled flexible printed circuit board is optically inspected for defects by a person or automatic image processing; a test step in which the partially or fully assembled flexible printed circuit board is subjected to a functional test; and a depaneling step in which at least one individual flexible printed circuit board is cut out, punched out or broken out from the substrate comprising a plurality of such individual flexible printed circuit boards.

[0147] 16. The method according to any one of items 14 or 15,

[0148] - wherein the frame is disassembled from the carrier plate after carrying out of the process step and is assembled, together with the substrate fixed therein, with another carrier plate; and

[0149] - wherein a further process step in the manufacture of the flexible printed circuit board to be assembled, in particular one of the process steps according to item 15, is carried out on the substrate fixed in the frame and resting on the support region of the further carrier plate.

[0150] 17. The method according to item 16,

[0151] - wherein the frame is flipped together with the substrate fixed therein before assembling the frame with the further carrier plate such that the first side of the frame faces the further carrier plate.

[0152] It will be appreciated by persons skilled in the art that numerous variations and / or modifications may be made to the invention as shown in the specific examples without departing from the spirit and scope of the invention as broadly described in the claims. The present examples are, therefore, to be considered in all aspects as illustrative and not restrictive.

[0153] LIST OF REFERENCE NUMERALS

[0154] 2 support arrangement

[0155] 4 substrate

[0156] 6 FPCB (panel)

[0157] 8 individual FPCB

[0158] 10 frame

[0159] 12 (first) side

[0160] 14 (second) side

[0161] 16 opening

[0162] 18 (first) suspension

[0163] 20 (second) suspension

[0164] 22 (third) suspension

[0165] 24 (fourth) suspension

[0166] 26 carrier plate

[0167] 28 arrow

[0168] 30 edge

[0169] 32 slot

[0170] 34 free end

[0171] 36 hook

[0172] 38 hole

[0173] 39 rivet

[0174] 40 spring

[0175] 41 spring

[0176] 42 spring

[0177] 43 leg

[0178] 44 leg

[0179] 45 hook

[0180] 46 lug

[0181] 47a,b part

[0182] 48 part

[0183] 50 support region

[0184] 52 border region 54 recess

[0185] 56 cavity

[0186] 58 pilot hole

[0187] 60 frame part

[0188] 62 frame part

[0189] 64 suspension

[0190] 66 suspension

[0191] 68 suspension

[0192] 70 suspension

[0193] 72 arm

[0194] 74 suspension

[0195] 76 flap

[0196] 77 perforations

[0197] 78 comerlOO - 165 step x (longitudinal) direction y (lateral) direction z (vertical) direction p suspension plane

Claims

CLAIMS1. A support arrangement (2) for fixing a substrate (4) of a flexible printed circuit board (6) to be assembled in a manufacturing process of the flexible printed circuit board (6), the support arrangement (2) comprising- a flat and rigid frame (10) extending in a suspension plane (P), said frame (10) having a first side (12) and a second side (14) opposite to the first side (12) and surrounding an opening (16) in which the substrate (4) is to be inserted; wherein the frame (10) and the opening (16) formed therein are open to both sides (12,14) of the frame (10) such that a substrate (4) fixed in the opening (16) of the frame (10) is freely accessible from both sides (12,14) of the frame (10);- at least three suspension elements (18, 20, 22, 24, 64, 66, 68, 70, 74) being distributed around an edge (30) of the opening (16) and attached to the frame (10) and each having a coupling contour (36) for temporarily fixing the substrate (4) in the opening (16) of the frame (10), said suspension elements (18, 20, 22, 24) comprising a first suspension element (18) fixedly attached to the frame (10) at at least two points such that the coupling contour (36) of this first suspension element (18) is held in a stationary position relative to the frame (10) within the suspension plane (P), and wherein all further suspension elements (20, 22, 24) are resiliently slidably attached to the frame (10) such that the respective coupling contour (36) of these further suspension elements (20, 22, 24) is movable perpendicularly or obliquely relative to an adjacent region of the edge (30) of the opening (16).

2. The support arrangement (2) according to claim 1, wherein each of the suspension elements (18, 20, 22, 24, 64, 66, 68, 70, 74) protrudes into the opening (16) with a free end (34), said free end (34) being provided with the respective coupling contour (36).

3. The support arrangement (2) according to claim 1 or 2,wherein the plurality of suspension elements (18, 20, 22, 24) comprise four suspension elements (18, 20, 22, 24) distributed relative to each other in a rectangular arrangement around the edge (30) of the opening (16), the four suspension elements (18, 20, 22, 24) comprising, in addition to said first suspension element (18),- a second suspension element (20),— which is arranged adjacent to the first suspension element (18) in the rectangular arrangement of the four suspension elements (18, 20, 22, 24), and— which is fixedly or pivotally attached to the frame (10) at one point and is resiliently slidably attached to the frame (10) at another point such that the coupling contour (36) of said second suspension element (20) is movable within the suspension plane (P) in a direction pointing towards the first suspension element (18),- a third suspension element (22),— which is arranged diagonally opposite to the first suspension element (18) in the rectangular arrangement of the four suspension elements (18, 20, 22, 24), and— which is resiliently slidably attached to the frame (10) such that the coupling contour (36) of said third suspension element (22) is movable within the suspension plane (P) in an inclined direction, with respect to adjacent sides of the rectangular arrangement of the four suspension elements (18, 20, 22, 24); and- a fourth suspension element (24),— which is arranged diagonally opposite to the second suspension element (20) in the rectangular arrangement of the four suspension elements (18, 20, 22, 24), and— which is resiliently slidably attached to the frame (10) such that the coupling contour (36) of said fourth suspension element (24) is movable within thesuspension plane (P) in an inclined direction, with respect to adjacent sides of the rectangular arrangement of the four suspension elements (18, 20, 22, 24).

4. The support arrangement (2) according to claim 3,- wherein the third suspension element (22) is resiliently slidably attached to the frame (10) such that the coupling contour (36) of said third suspension element (22) is movable within the suspension plane (P) in a direction pointing towards the first suspension element (18); and- wherein the fourth suspension element (24) is resiliently slidably attached to the frame (10) such that the coupling contour (36) of said fourth suspension element (24) is movable within the suspension plane (P) in a direction pointing towards the second suspension element (20).

5. The support arrangement (2) according to claim 3,- wherein the third suspension element (22) is resiliently slidably attached to the frame (10) such that the coupling contour (36) of said third suspension element (22) is movable within the suspension plane (P) in a direction being aligned at an angle of 45° to adjacent sides of the rectangular arrangement of the four suspension elements (18, 20, 22, 24); and- wherein the fourth suspension element (24) is resiliently slidably attached to the frame (10) such that the coupling contour (36) of said fourth suspension element (24) is movable within the suspension plane (P) in a direction being aligned at an angle of 45° to adjacent sides of the rectangular arrangement of the four suspension elements (18, 20, 22, 24).

6. The support arrangement (2) according to any one of claims 1 to 5, wherein each of the plurality of suspension elements (18, 20, 22, 24, 64, 66, 68, 70) is pivotally or resiliently bendably attached to the frame (10) in a direction (z) perpendicular to the suspension plane (P).

7. The support arrangement (2) according to claim 6, wherein each of the plurality of suspension elements (18, 20, 22, 24, 64, 66, 68, 70) is attached to the frame (10) at a distance from the edge (30) of the opening (16), and wherein the suspension elements (18, 20, 22, 24, 64, 66, 68, 70, 74) are arranged in slots (32) of the frame (10) such that they can be pivoted or elastically bent out of said suspension plane (P) towards both the first side (12) and the second side (14) of the frame (10).

8. The support arrangement (2) according to any one of claims 1 to 7, further comprising at least one carrier plate (26) that can be assembled with the frame (10) such that a support region (50) of the carrier plate (26) for supporting the substrate (4) fixed in the frame (10) is aligned with the opening (16) of the frame (10).

9. The support arrangement (2) according to claim 8, wherein the support region (50) of the carrier plate (26) protrudes from a border region (52) of the carrier plate (26) surrounding it, such that the support region (50) extends into the opening (16) of the frame (10) or through the opening (16) of the frame (10) for deflection of the substrate (4) out of the suspension plane (P) when the carrier plate (26) is assembled with the frame (10).

10. The support arrangement (2) according to any one of claims 8 or 9, wherein the frame (10) can be assembled with the carrier plate (26) in two alternative positions such that either the first side (12) or the second side (14) of the frame (10) faces the carrier plate (26).

11. The support arrangement (2) according to any one of claims 8 to 10, wherein the frame (10) and the carrier plate (26) are provided with corresponding pilot structures (58) for aligning the frame (10) with the carrier plate (26).

12. The support arrangement (2) according to any one of claims 8 to 11,wherein the support region (50) of the carrier plate (26) is provided with at least one cavity (56) providing free space adjacent to the substrate (4) when the frame (10) with the substrate (4) fixed therein is assembled with the carrier plate (26).

13. The support arrangement (2) according to any one of claims 8 to 12, comprising a plurality of carrier plates (26) which differ in the configuration of the support region (50), wherein the frame (10) can be assembled selectively with each of the plurality of carrier plates (26).

14. A method of manufacturing a flexible printed circuit board (6) using a support arrangement (2) according to any one of claims 8 to 13,- wherein a substrate (4) of the flexible printed circuit board (6) to be assembled is fixed in the frame (10) of the support arrangement (2);- wherein the frame (10) together with the substrate (4) fixed therein is assembled with the carrier plate (26) or one of a plurality of carrier plates (26) of the support arrangement (2) such that the second side (14) of the frame (10) faces the carrier plate (26) and the substrate (4) rests on the support region (50) of the carrier plate (26); and- wherein a process step in the manufacture of the flexible printed circuit board (6) to be assembled is carried out on the substrate (4) fixed in the frame (10) and resting on the support region (50) of the carrier plate (26).

15. The method according to claim 14, wherein the process step is selected from one of- a screening step (104, 114) in which a solder and / or flux is applied to the substrate (4); a placement step (106, 116) in which surface-mounted electronic components are placed on a surface of the substrate (4);a heating step, in particular a soldering step (110, 120), in which components previously placed on the surface of the substrate (4) are electrically conductively connected to conductor tracks on the substrate (4);- a filling step (124, 132) in which at least some of the components mounted on the substrate (4) are underfilled with a potting compound or embedded in a potting compound;- an inspection step (140, 146) in which the partially or fully assembled flexible printed circuit board (6) is optically inspected for defects by a person or automatic image processing;- a test step (138) in which the partially or fully assembled flexible printed circuit board (6) is subjected to a functional test; and- a depaneling step (154) in which at least one individual flexible printed circuit board (8) is cut out, punched out or broken out from the substrate (4) comprising a plurality of such individual flexible printed circuit boards (8).

16. The method according to any one of claims 14 or 15,- wherein the frame (10) is disassembled from the carrier plate (26) after carrying out of the process step and is assembled, together with the substrate (4) fixed therein, with another carrier plate (26); and- wherein a further process step in the manufacture of the flexible printed circuit board (6) to be assembled, in particular one of the process steps according to claim 15, is carried out on the substrate (4) fixed in the frame (10) and resting on the support region (50) of the further carrier plate (26).

17. The method according to any one of claim 16,- wherein the frame (10) is flipped together with the substrate (4) fixed therein before assembling the frame (10) with the further carrier plate (26) such that the first side (14) of the frame (10) faces the further carrier plate (26).

Images