JPH0143708Y2 - - Google Patents

Description

[Detailed explanation of the invention] This invention mainly applies to through-hole boards.
This article relates to improvements in circuit burning films for burning electrical circuits, including terminal connection rounds for IC electronic components such as SSI, MSI, and LSI.

Electrical circuits on through-hole boards are generally made by baking a circuit onto a copper foil that has been surface-treated and pasted onto the board, exposing unnecessary parts of the copper foil surface other than the circuit, and exposing the exposed parts to light. It is formed by removing it by electrical or chemical etching.

On the other hand, on the through-hole board, a round of copper foil is formed on the opening edge of the insertion hole for the electronic component terminals arranged at a fixed pitch to establish electrical continuity with the terminals. Therefore, as shown in FIG. Naturally, the baked film 1 also has a round 2 for leaving a copper foil round. This film round is especially suitable for double-sided printed through-hole board printing films.
Because it is necessary to determine the pitch of the rounds on both sides, it is not possible to apply a solid coating.
Therefore, a translucent hole 2a with a diameter of 0.4 mm is usually provided at the center of a round having a predetermined diameter.

By the way, if this center hole remains as it is when the circuit is printed onto the board, the copper foil round of the board will be etched more than necessary due to the light leaking through the hole, which may cause a poor connection between the terminals. Therefore, it is filled before printing to prevent light leakage.

Filling the center hole has traditionally been done manually because film is not a mass-produced product, but this work is extremely inefficient and often causes defects in the electrical circuit. ing.

That is, conventionally, the center hole of the round is filled in one by one using a thin-shaft felt pen, which requires a considerable amount of effort and time to fill in the holes on a single sheet of printed film. Also, as the tip of the felt pen gradually collapses, the ink will overflow from the round, and in areas where circuits are intricately squeezed into a narrow space, the overflowing ink layer may become a bridge and cause a short circuit with other circuits. When this type of situation occurs, finding the short circuit becomes a difficult task.

The present invention has been made in view of the above, and its object is to provide a circuit-printed film that allows filling of rounds easily, quickly, and accurately.

That is, in this invention, the round size is usually 2.54 mm x 7.62 mm.
A large number of regularly arranged points with a pitch of mm or twice that (14, 16, 24,
Focusing on the 40 and 50 pin package, in which rounds are formed in one place, we placed a transparent sheet film on top of the printed film rounds printed at a fixed pitch and applied a transparent adhesive. According to this structure, the center hole of the printing film round is hidden by a light-shielding printed layer formed on this sheet film at the same pitch as the printing film round.
The rounds of one or more packages can be filled all at once, and short circuits do not occur between circuits.

FIGS. 2 and 3 show an example of the printed film of the present invention, in which the center hole 2a of the round 2 is filled on one side of the printed film 10 on which the same circuit as that shown in FIG. 1 is printed. A sheet film 11 is attached via a transparent adhesive 12.

The above-mentioned sheet film 11 is made of a light-transmitting material with a light-shielding printed layer 13 (Fig. 3) that fits completely inside the round at the same pitch as the round 2 but is larger than the diameter of the center hole. , the round center hole 2a is hidden by this printed layer 13.

The adhesive 12 may be applied when pasting the sheet film 11, but workability may be improved by applying a pressure-sensitive adhesive to a sheet having the required number of printed layers 13 in advance and pasting it on release paper. Excellent.

Further, the printed layer 13 of the sheet film is desirably formed on the adhesive side of the sheet to prevent damage.

Furthermore, as shown by the chain line A in Figure 2, between the round packages arranged vertically and horizontally every other row, other round packages connected to the terminals of the electronic components provided on the other side of the board are placed in a staggered manner with the previous round. When the holes are arranged so that the round holes are hidden, as shown in Fig. 4, the sheet film 11' that hides the remaining round holes is superimposed and pasted on the sheet film 11 that hides the rounds in every other row. This is more economical than using a single sheet film for blindfolding as shown in FIG. 2, since fewer types of sheet films need to be prepared.

Here, the random round denoted by 2' is
Considering the total number of rounds, there are only a few, so the center hole can be crushed with a felt-tipped pen or the like as usual.

Note that the round shape of the baked film of the present invention is not limited to a circular shape. Further, in the margin of the film 10, photoelectric marks 14 for positioning with respect to the substrate are provided, as in the case of conventional films.

As described above, in the circuit printing film of the present invention, the regularly arranged round center holes are covered with a sheet film having a light-shielding printed layer of the same pitch, so that one or more packages can be printed. round holes can be filled all at once, which greatly improves work efficiency.

Also, filling in the eyes with a felt-tip pen is done only for random rounds. Depending on the circuit configuration, this random round may not occur at all, so short circuits in the circuit due to operational errors are greatly reduced.

[Brief explanation of the drawing]

FIG. 1 is a plan view showing a conventional printing film, and FIG. 2 is a plan view showing an example of the printing film of the present invention.
FIG. 3 is an enlarged sectional view showing the main parts thereof, and FIG. 4 is a plan view showing the main parts of another embodiment. 2, 2'...Round, 2a...Center hole,
10... Baking film, 11, 11'... Sheet film, 12... Adhesive, 13... Light-shielding printing layer, 14... Photoelectric mark.

Claims (1)

[Scope of Claim for Utility Model Registration] (1) In a circuit printing film in which an electric circuit including rounds for connecting terminals of electronic components is printed on a through-hole board, a translucent A light-shielding printing layer formed on the sheet film at the same pitch as the round of the printing film hides the center hole of the round of the printing film. Circuit printing film for through-hole boards. (2) The circuit-printed film for through-hole boards according to claim 1, wherein the light-transmitting adhesive is a pressure-sensitive adhesive applied to a sheet film in advance. (3) A circuit for a through-hole board according to claim 1 or 2 of the utility model registration claim, wherein the light-shielding printed layer is formed on the adhesive side of the sheet film. Burnt film. (4) Circuit burning for a through-hole board according to any one of claims (1) to (3) of the utility model registration claim, characterized in that several film sheets are laminated and pasted at the same location. film.