JPS5812451Y2 - Circuit mounting structure for crystal wristwatches - Google Patents

Description

[Detailed explanation of the invention] The purpose of this project is to simplify the implementation of electronic circuits, which account for a major part of the manufacturing cost of precision instruments such as quartz wristwatches, which are expected to be exhibited in all four versions in the future, and to improve reliability. The aim is to provide stable products at high prices and at low prices.

The gist of this proposal is a printed circuit board (copper foil bonded to an insulating board) that was conventionally used to configure electronic circuits.
This means that the IC 1 and each electrical element are connected directly to other electrical elements using the lead frame of the IC.

The conventional method using printed circuit boards leaves only the necessary parts of the copper foil on the printed circuit board due to corrosion.
Alternatively, an electronic circuit was constructed by removing unnecessary parts and soldering electrical elements there.

Here, when considering the manufacture of printed circuit boards, corrosion → repressing (external shape removal, hole drilling, etc.) → burr removal (external shape).

(polishing inside the hole), but corrosion takes time, accuracy is poor, and plating requires special consideration, unlike metal plating, and there are many burrs and burrs when punching out, which must be removed. However, if barrel polishing, which has the highest workability, is used, the plating on the copper foil parts may come off, or the copper foil parts themselves may come off, so the only option is to manually polish each piece one by one.

As described above, the printed circuit board method is relatively expensive, and since each element is connected through the copper foil, there are inevitably many soldering points, which is also a factor that reduces the reliability of electronic circuits. It is.

According to the present invention, each element can be wired using the lead frame of the IC, so there is no need for the conventional method, and it is very advantageous in producing a cheap and stable electronic circuit.

The details of the present invention will be explained with reference to figures showing one embodiment.

FIGS. 1, 2, and 1 show conventional circuit mounting structures. Reference numeral 1 denotes a printed circuit board, which consists of a board 1a and a copper foil portion 1b.

2 is the IC block, which is the heart of the crystal clock. MOS IC3 has a built-in oscillation frequency division by 9 and a drive circuit, and lead frames 4a, 4b, 4C, 4d, which are connected to the respective electrodes of MOS IC3. 4e, 4f, and 4g are integrally molded with resin.

Further, 5 is a trimmer capacitor for adjusting the rate of the crystal clock, and 6 is a crystal oscillator, each of which is soldered to the copper plate 1b of the printed circuit board 1 as shown in the figure.

This structure has the drawbacks mentioned above. Next, the present invention will be explained with reference to FIGS. 3 and 4.

7 is an insulating plate, which corresponds to 1a in FIGS. 1 and 2.

IC block 2. Trimmer capacitor 5. crystal oscillator 6
The structure and function are the same as those in FIGS. 1 and 2 except for the lead frame of the IC block.

IC block 2 leads 7L/-A8 a, 8 b,
8C, 8d, 8e, 8f, 8g are MOS I
It is the same as 4a to 4g in FIGS. 1 and 2 in that it is connected to C3 and integrally molded with resin, but it also functions as the copper foil 1b in FIGS. 1 and 2.

That is, as shown in the figure, node frames 8a to 8g are bonded to an insulating plate 7, and trimmer capacitors 5. to 8g are attached to lead frames 8a to 8g. A crystal oscillator 6 and the like are soldered.

Further, the lead frame 8f passes through a hole in the circuit board and serves as an elastic contact piece that is elastically connected to the coil lead plate electrode 9.

With the structure shown in the figure according to the present invention, a printed circuit board is unnecessary and the drawbacks of the conventional method are eliminated.

That is, since the lead frame is made of metal, it can be press-cut and can be plated freely.

Furthermore, when the insulating plate is pressed out, burrs, cracks, etc. will appear as in the past, but peeling of the copper foil will not be a problem, so it can be efficiently removed by barrel polishing.

As described above, according to the present invention, manufacturing costs are significantly reduced.

Also, when comparing the locations of soldering in FIG. 1 and FIG. 3, there are four fewer locations in FIG. 3 than in FIG. 1.

The biggest factor that reduces the reliability of electronic circuits is soldering, and the fewer places there are soldered, the higher the reliability will be.

Also, of course, manufacturing costs are reduced.

As mentioned above, this project is aimed at lowering the cost of electronic circuits for precision instruments such as crystal watches, which are becoming increasingly electronic.

It greatly contributes to stabilization.

Incidentally, the lead frames 8a to 8g in the figure and the insulating plate 7 only have to be fixed to each other, and any means for doing so may be used.

Further, if there is no problem in terms of strength, the insulating plate 7 may be omitted, and in this case, the cost will be further reduced.

[Brief explanation of the drawing]

FIG. 1 is a plan view showing the circuit mounting structure of a conventional quartz wristwatch, and FIG. 2 is a sectional view thereof. 1... Printed circuit board, 1a... Board part of printed board, 1b... Copper foil part of printed board, 4a, 4b, 4C, 4d, 4e, 4f ,
4 g-.
...Insulating plate, 8a, 8b, 8C, 8d
, 8e, 8f, 8g...IC lead frame.

Claims (1)

[Scope of utility model registration request] In a circuit mounting structure for a crystal wristwatch, which includes an IC block in which a MOS IC chip is resin-molded, electronic components such as a crystal resonator and a trimmer capacitor, and an insulated circuit board that holds at least the IC block, the IC block is The resin mold has a lead frame end and a wire connection from the MO8IC chip electrode to the lead frame end, and the lead frame is connected to the I
It is fixed to the insulated circuit board integrally with the C block, and the other end of the lead frame serves as an elastic contact piece with the coil lead plate electrode, and also serves as a direct connection terminal for the leads of the crystal resonator and trimmer condenser. A circuit mounting structure for a crystal wristwatch characterized by being configured to