GB2151578A - Tape-mounted electronic components assembly - Google Patents

Abstract

A tape carrier assembly comprising a plurality of the electronic components 12 mounted on a support tape 22 at regular intervals by fixing the lead terminals 13 to the tape is characterised in that the support tape 22 is formed from a thermoplastic synthetic resin material containing inorganic fillers. Such a tape is superior in dimensional accuracy, tensile strength and heat-resistance and facilitates the high-speed taping feeding and automatic insertion of the electronic components into a circuit substrate. When the support tape 22 is used together with an adhesive tape, the tape 22 may be subjected to surface treatments to improve adhesion of the adhesive tape. In other embodiments (Figs. 4-6), the component leads are heated and pressed into the tape 22 to bond them thereto or are adhered to the tape by adhesive. <IMAGE>

Description

SPECIFICATION Tape mounted electronic components assembly The present invention relates to an electronic components assembly in which the electronic components for example, resistors or condensers, provided with terminal leads are mounted at regular intervals on a tape.

An automatic inserting machine is used in order to mount electronic components provided with terminal leads on a print substrate and the electronic components are provided in the form of a tape-mounted assembly, in which they are mounted at regular intervals on a tape, in order to permit automatic insertion thereof.

Referring to figs. 1 and 2, which illustrate the construction of a conventional tapemounted electronic components assembly, a base tape 11 made of paperboard or cardboard, such as, Kraft liner, has the terminal leads 1 3 of a plurality of electronic components 1 2 arranged on one side thereof at a regular pitch P. An adhesive tape 1 4 is stuck onto said base tape 11 to hold the leads 1 3 between the base tape 11 and the adhesive tape 1 4 and so that the leads are fixedly held between the tapes, and the base and adhesive tapes are provided with guide holes 1 5 for transporting or positioning purposes and formed by punching along the tapes at the regular pitch P.

In the case of the above described tapemounted electronic components assembly, in general, after each electronic component 1 2 is removed from the tape in an automatic production line for electronic instruments, it is mounted on a print substrate or the like for the electronic instruments. The tape-mounted assembly is subjected to positional detection by photoelectric sensors or the like at many positions in the automatic inserting process or the production process of the assembly.However, since the conventional tape-mounted assembly is formed of a base tape 11 made of cardboard, as described above, paper dust is produced from the base tape 11 owing to friction and the like during movement of the assembly, whereby there is a problem with paper dust adhered to the luminous surfaces and light-receiving surfaces of the photoelectric sensors which results in misoperation to the automatic inserting machine or the like.

There is also a problem of environmental pollution.

In addition, since for transportation and storage purposes a tape-mounted assembly of this type is housed in a box type container (not shown) in layers formed by folding at regular lengths, there is the possibility that the base tape 11 may be torn at the folds when fed through the automatic inserting machine or the like.

Although it has been proposed that the base tape 11 should be formed of synthetic resin material instead of cardboard, synthetic resins have several disadvantages, such as (1) they have a tensile strength less than that of cardboard (2) they have a larger elongation than cardboard, and (3) they contain no functional group, thereby showing no affinity for adhesives of the adhesive tape 1 4. Accordingly, although where the base tape 11 is formed from synthetic resin material, the above described misoperation of photoelectric sensors, environmental pollution and the like due to paper dust can be prevented, since synthetic resins are inferior to cardboard in tensile strength, a base tape 11 formed from synthetic resin material is apt to be torn by an external force and, in addition, there is the possibility that the positions of the guide holes 1 5 may be shifted when a tensile force is applied to the base tape 1 1 because synthetic resin tape has a larger percentage elongation, so that accuracy is reduced. Moreover, since the adhesion of synthetic resin material to the adhesive tape 1 4 is not so strong, owing to the poor affinity of synthetic resin for the adhesives of adhesive tape 14, new problems arise, such as, the electronic components 1 2 may be unexpectedly inclined by an external force or the like, as shown by the imaginary lines in fig. 1, so that a base tape formed of synthetic resin has not hitherto been a practical proposition.

Thus, it is an object of the present invention to provide a tape-mounted electronic components assembly which has superior dimensional accuracy, tensile strength and heat- and cold-resistance, and which enables the highspeed production thereof and handling in an automatic inserting machine and, in addition, improves the reliability of handling.

It is another object of the invention to provide an electronic components assembly which avoids the production of dust, such as paper dust has improved mechanical strength and adhesion, and exhibits high accuracy and a greater holding power for electronic components.

It is a further object of the invention to provide a comparatively inexpensive electronic components assembly.

In order that the present invention may be more readily understood, reference will now be made to the accompanying drawings, in which: Figure 1 is a front view of a conventional tape-mounted electronic components assembly, Figure 2 is a vertical section on the line 1111 of figure 1, Figure 3 is a front view of a first embodiment of the present invention, Figures 4 to 6 are sectional views illustrating different constructions of the first embodiment shown in Figure 3, Figure 7 is a perspective view of a second embodiment of the present invention, Figure 8 is a sectional view taken along the line VIII-VIII of Figure 7, and Figure 9 is a diagrammatic flow chart illustrating one example of the production and utilisation of the second embodiment of the present invention.

Referring to Figs. 3 to 6 of the accompanying drawings, a support tape 21, on which electronic components 1 2 are mounted, comprises a thermoplastic resin tape 22 containing inorganic fillers, the terminal leads 1 3 of a large number of the electronic components 1 2 being fixedly mounted on the support tape 21 at regular intervals, and the support tape being provided with perforations 23 also formed at regular intervals.

The support tape 21 shown in Figs. 3 and 4 is formed solely of the synthetic resin tape 22 and electronic components 1 2 are mounted on this synthetic resin tape by placing the terminal leads 1 3 of the electronic components 1 2 on the tape 22 and then heating them under conditions in which the leads 1 3 are pressed against the synthetic resin tape, thereby directly to weld the leads 13 to the tape 22.

The support tape 21 shown in Figs. 5 and 6 is formed solely of the synthetic resin tape 22 but differs from the one shown in Figs. 3 and 4 in the construction for mounting the electronic components 1 2 thereon. In Fig. 5, the terminal leads 1 3 are mounted on the synthetic resin tape 22 by placing the leads 1 3 on the tape 22 and applying adhesive 24 on the leads and the tape so that leads 1 3 are covered with the adhesive 24.

In Fig. 6. terminal leads 1 3 are mounted on a synthetic resin tape 22 by applying adhesive 25 on the the upper side of the tape 22 and then placing the terminal leads 1 3 on the adhesive 25.

The synthetic resin tape 22 is formed from thermoplastic synthetic resins containing various kinds of fillers. The thermoplastic resins include vinyl-chloride, polystyrene, polyethylene, polyester. polypropylene, polyamide or mixtures of two or more of these materials.

The fillers 26 include one or more kinds of powdery or fibrous inorganic materials, such as, calcium carbonate, glass powders, silica, talc or clay. They may be contained in the synthetic resin tape in a ratio of 5 to 80% by weight and, preferably, 10 to 60% by weight.

Since synthetic resin tape 22 formed of thermoplastic resins containing fillers 26 is remarkably superior to a synthetic resin tape formed of thermoplastic resins, to which no fillers are added, in dimensional accuracy, tensile strength, heat-resistance and the like, the high-speed taping and automatic insertion of electronic components assemblies can be achieved.

The characteristics of a synthetic resin tape formed of polypropylene, as the synthetic resin, containing calcium carbonate, as the fillers 26 in a ratio of 20% by weight, will now be compared with those of a synthetic resin tape formed solely of polypropylene.

(A) Dimensional Accuracy Where a synthetic resin tape is drawn in its longitudinal direction by a force of 5009 at an interval of 20cm, the percentage elongation of a synthetic resin tape according to the present invention is reduced to about half of that of a synthetic resin tape containing no filler.

(B) Tensile Strength The tensile strength of a synthetic resin tape containing no filler amounts to merely 3.2 to 7.0 kg/mm2. On the other hand, the tensile strength of a synthetic resin tape containing fillers improved to 10.0 to 15.0 kg/mm2.

(C) Heat-resistance A synthetic resin tape containing fillers is durable up to 1 30 to 150 C whilst a synthetic resin tape containing no filler is durable only up to 100 to 110 C.

(D) Cold-resistance A synthetic resin tape containing fillers is durable down to - 1 20'C whilst a synthetic resin tape containing no filler is durable only down to -Sto -- 10"C.

A stretched synthetic resin tape may be used in order further to improve the synthetic resin tape 22 in dimensional accuracy and tensile strength. Either uniaxial stretching for improving the strength in the longitudinal direction (X in Fig. 3) of the synthetic resin tape, or biaxial stretching for improving the strength in both the longitudinal and widthwise directions (X,Y in Fig. 3) of the tape may be adopted. Stretched synthetic resin tape 22 is remarkably superior to the unstretched tape in dimensional accuracy, tensile strength and the like for achieving high-speed production of electronic components assemblies and automatic insertion of components.

In the second embodiment of the invention illustrated in Figs. 7 and 8, a support tape 21 comprises a thermoplastic synthetic resin tape 22 containing inorganic fillers and an adhesive tape 27 stuck on to the tape 22, the terminal leads 1 3 of the electronic components 1 2 being disposed between the tape 22 and the adhesive tape 27, and perforations 23 for positioning purposes being formed between the leads of adjacent components 1 2. The synthetic resin tape 22 is formed of resin materials, such as, thermoplastic resins containing inorganic fillers and at least one side thereof, to which the adhesive tape 27 is stuck, is subjected to surface treatment to improve the bonding capacity.

Referring now to Fig. 9, thermoplastic resin material 28 used in the synthetic resin tape 22 comprises, for example, polypropylene which is inexpensive and superior in workabil ity. However, since polypropylene shows insu fficient tensile strength, bending strength and percentage elongation and is remarkably inferior in its affinity for the adhesive of the adhesive tape 27 owing to the absence of functional groups therein, that is to say, it is remarkably inferior in bonding capacity, inorganic fillers 29 are added to polypropylene 28 to give functional groups to the tape 22, itself, to some extent and, in addition, improve the tensile strength, bending strength and percentage elongation thereof. For example, calcium carbonate (CaCO3), which is inexpensive and superior in practical usefulness, is used as the inorganic fillers 29.

Specifically illustrating a method of compounding, powdery calcium carbonate is added to the powdery polypropylene 28 at a ratio of 5 to 80% by weight, preferably 10 to 60% by weight, and the mixture is heated to blend in a mixer 30. Then, the resulting compound is molded in a molding machine 31 to give the appointed shape and size. The molded sheet is formed as a tape to obtain a half-finished product 22a of synthetic resin tape 22. At this time, surfactants (not shown) may be disposed in the mixer 30 in order uniformly to disperse the calcium carbonate 29 in the polypropylene.

Not only the above described tensile strength, bending strength and percentage elongation can be improved but, also, functional groups are formed on the surface of the synthetic resin tape 22, whereby comparatively superior bonding capacity is given to the synthetic resin tape 22. However, in order further to improve bonding capacity to give the sufficient durability required for the final products, one side of the synthetic resin tape 22 is subjected to a surface treatment. For example, an easily practicable flame treatment may be adopted as this surface treatment.

That is to say. the selected surface of the synthetic resin tape 22 Is oxidized to form a sufficient amount of functional group near the surface by feeding the synthetic resin tape 22, at high speed, over the flame of a gas burner 32 having temperatures of 1000 to 2500"C, preferably 1 500 to 2000"C.

In addition, since functional groups can be prevented from being eliminated even after the compound is formed in the form of synthetic resin tape, whereby the effect of surface treatment is kept for a long time by adding calcium carbonate 29 to polypropylene 28, the synthetic resin tape 22 can be easily controlled.

Also in this embodiment, vinyl chloride, polystyrene, poiyethylene, polyamide, polyester or mixtures of two or more of these materials can be used as the thermoplastic resin material 28 in addition to polypropylene.

Moreover, one or more kinds of powdery or fibrous inorganic materials, such as, glass powder, silica, talc or clay can be used as fillers in addition to calcium carbonate. In this event, polyamide, polyester, or the like have functional groups per se and practicable superior bonding capacity differently from polypropylene. It is however necessary, even for resin materials 28, which have sufficient bonding capacity per se, such as polyamide and polyester, in order to improve mechanical strength and percentage elongation, to add the inorganic fillers 29 to the resin materials 28.

However, although mechanical strength and the like can be improved by adding the inorganic fillers 29, since bonding capacity is reduced in comparison with that prior to the addition of inorganic fillers 29, it is necessary that the surface on which the adhesive tape 27 is stuck be subjected to surface treatment.

In addition to flame treatment, physical treatments, such as corona discharge treatment and plasma etching treatment, chemical treatments, such as treatments which acids and treatments with solvents, mechanical surface-roughening treatments by sanding and the like, can be adopted as the surface-treating method for the synthetic resin tape 22.

The resulting electronic components assembly according to the present invention may be housed in a box-like container (not shown) for transportation and storage purposes in a condition in which it is folded in appropriate lengths or wound around a reel (not shown).

In use, for example, in a production line for electronic instruments, the perforations 23 are engaged with positioning means of an automatic inserting machine (not shown) to convey the electronic components assembly to the appointed position, the terminal leads 1 3, being cut at the midway portion, as shown by the chain dotted line I in Fig. 7, and then only the electronic components 1 2 are separated and inserted in a circuit substrate of an electronic instrument.

Since, as described above, the support tape, to which the terminal leads of the electronic components are attached, comprises a synthetic resin tape formed of thermoplastic synthetic resin to which inorganic fillers are added, the dimensional accuracy and tensile strength of the support tape can be remarkably improved in comparison with a conventional resin tape and, in addition, the highspeed production and handling of electronic components in an automatic inserting machine, as well as the accuracy of the automatic insertion of electronic components can be improved, Furthermore, since heat-resistance and coldresistance of the support tape can be improved, the quality of a tape-mounted electronic components assembly does not exhibit deterioration even in a high-temperature or low-temperature working environment.

In addition, since the support tape is formed of a synthetic resin tape, dust can be prevented from being produced, contrary to the case where cardboard is used, whereby the control of the automatic inserting machine and the like by means of sensors can be more surely achieved and, as a result, automatic production and insertion can be achieved.

Claims (11)

1. A tape-mounted electronic components assembly in which the support tape to which leads of the electrical or electronic components are attached comprises a synthetic resin tape formed from thermoplastic synthetic resin material and inorganic fillers.

2. A tape-mounted electronic components assembly as claimed in claim 1, in which the thermoplastic synthetic resin material comprises vinyl chloride, polystyrene, polyethylene, polypropylene, polyamide, polyester or mixtures thereof.

3. A tape-mounted electronic components assembly as claimed in claim 1 or 2, in which the inorganic fillers comprise one or more kinds of powdery or fibrous inorganic materials, such as, calcium carbonate, glass powder, silica, talc or clay.

4. A tape-mounted electronic components assembly as claimed in claim 1, 2 or 3, in which the inorganic fillers are contained in the synthetic resin tape in a ratio of 5 to 80% by weight, preferably 10 to 60% by weight.

5. A tape-mounted electronic components assembly as claimed in any one of the preceding claims, in which the synthetic resin tape is a uniaxially stretched tape.

6. A tape-mounted electronic components assembly as claimed in any one of the preceding claims 1 to 4, in which the synthetic resin tape is a biaxially stretched tape.

7. A tape-mounted electronic components assembly as claimed in any one of the preceding claims, in which the support tape comprises said synthetic resin tape in combination with an adhesive tape.

8. A tape-mounted electronic components assembly as claimed in claim 7, in which the surface of the synthetic resin tape is subjected to surface treatment in order to give it bonding capacity to the adhesive tape.

9. A tape-mounted electronic components assembly as claimed in claim 8, in which the synthetic resin tape is formed from resin exhibiting superior bonding capacity, the deterioration in bonding capacity due to the addition of the inorganic fillers being alieviated by the surface treatment.

1 0. A tape-mounted electronic components assembly as claimed in claim 8 or 9, in which the surface treatment comprises a flame treatment, corona discharge treatment, plasma etching treatment, treatments with acids, treatments with solvents or sanding.

11. A tape-mounted electronic components assembly asd claimed in claim 10, in which the surface of the synthetic resin tape is oxidized by a flame treatment, said flame treatment being carried out by the high-speed advance of the synthetic resin tape over a flame having temperatures from 1000 to 2500"C and preferably 1 500 to 2000"C.

1 2. A tape-mounted electronic components assembly substantially as hereinbefore described with reference to Figs. 3 and 4 or 5 or 6 or Figs. 7 and 8 of the accompanying drawings.

1 3. A method of making a tape-mounted electronic components assembly substantially as hereinbefore described with reference to the accompanying drawings.