JPH0118397B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to the structure of a circuit section used in an electronic wristwatch.

[Conventional technology]

Conventionally, the structure of the circuit section used in electronic wristwatches has been constructed by mounting necessary electronic components on a circuit board made of ceramic, glass-epoxy resin, etc., and connecting them by patterns.

However, it has become impossible to obtain a circuit board as described above that satisfies the growing need for thinner products.

In response to this thinning, flexible printed circuit boards have recently appeared, and good results have been obtained.

[Problem that the invention seeks to solve]

However, since the flexible circuit board alone lacks rigidity, it has disadvantages in that it is difficult to assemble into a wristwatch and has poor retention of components.

The present invention has been made in view of the above points, and its purpose is to provide a circuit structure suitable for a thin watch.

[Means for solving problems]

In order to achieve the above object, the present invention interposes a flexible circuit board between a base plate and an elastic metal plate having a size and shape that covers most of the flexible circuit board, and the elastic metal plate is attached to a back cover. The main feature is that the elastic metal plates are arranged so as to face each other, and that an elastic holding portion for holding the electronic components is formed on the elastic metal plate.

[Effect]

With the above configuration, the electronic component can be installed while being held by the elastic metal plate as if it were mounted on a flexible circuit board, or the electronic component can be held after being installed.

〔Example〕

Hereinafter, one embodiment of the present invention will be described based on the drawings.

FIG. 1 is a plan view of the crystal oscillation wristwatch according to the present invention, viewed from the back cover side. At the upper right in the figure, a switching mechanism operated by a crown (not shown) and a needle setting mechanism are mainly arranged. The central part of the winding stem 7 is loosely fitted into a horizontal hole in the main plate 1, and a mandarin duck 8 is provided so as to straddle the winding stem 7. Mandarin duck 8
is fixed with screws, and the cannula 9 having the cleat 9b is
The switching lever 10 is swung around the switching lever stud 10a planted on the base plate 1. Small railway car 1
1 and the intermediary wheel 12 that meshes with it are the switching lever 10
It is placed on. Mandarin duck 8 and switching lever 10
A back presser 13 that clamps a part of the
The pin 8a implanted in the mandarin duck 8 is formed into two adjacent holes 13a which are determined by the spring force of the pin 8a in the upper and lower surface directions, and the battery 38 is pushed out from the side direction to conduct electricity and stabilize the position of the battery 38. It has a bent portion 13b and is fixed to the base plate 1 with two screws.
The mandarin duck 8 has an elongated hole 8b in a direction perpendicular to the axial direction of the winding stem 7 loosely fitted into a shaft 1c planted in the main plate 1, and a (+) spring 8 welded to the mandarin duck 8.
c, conducts with the (+) lead portion 25a of the conductive sheet 25, which is a flexible circuit board, and contacts the contact point 26, which is insulated and implanted in the base plate 1, by its spring force in the direction of the upper and lower surfaces. 1d is a hole into which the dial leg loosely fits, 35b is a dial screw that presses and fixes the dial leg, and 37 is a mechanical screw that fixes the watch movement to the watch case (not shown). There is another one in a symmetrical position.

An electromechanical converter serving as a prime mover is placed in the upper left portion of FIG. 1. The coil 19 is inserted into a slightly larger hole provided in the main plate 1, and the bent portions of both ends of the winding core 19a are tightly attached to the end portions of the stator 17, which is attached to the dial side of the main plate 1 with screws.
It is held by fixing it with e.

30 is a magnetic shielding plate to which a coil holder 29 is fixed with pins 29a, and these integrated pieces are attached to the base plate 1 with screws 29b. 17a
are notches in the stator 17 that determine the initial position of the rotor 6, and are also formed at symmetrical positions. 18 is a stator plate made of brass material, approximately stator 17
It has the same shape as . Reference numeral 20 denotes a terminal plate of a printed circuit board attached to a protruding portion of the coil winding core 19a that is remote from the magnetic circuit.

A deceleration wheel train and an indicator wheel train are shown in the center of FIG. 1, and in this embodiment, they are all housed in the lower surface of the main plate 1, that is, in the milled part on the dial side. The rotor 6 of the prime mover is rotated by a stator 17 which receives an alternating magnetic flux excited by a coil 19. A fourth wheel & pinion 5, a third wheel & pinion 4, and a second wheel & pinion 3, which are a reduction gear train, decelerate the rotation of the rotor 6. The shaft supports in the upper surface direction of the rotor 6, the fourth wheel 5, and the third wheel 4 are polyacetal resin bushings pressed and fixed to the main plate 1, and may be oil-free. The shaft supports in the lower surface direction of the fourth wheel 5 and the third wheel 4 are bushes similar to those described above, which are embedded in the train wheel bridge 2 screwed to the lower surface of the main plate 1. The center wheel 3 is a center shaft 1 planted in the main plate 1
It is loosely fitted in a. Hinoura car 15, which is the designated wheel train
The hour wheel 16 receives rotation from the reduction gear train. The Hino-ura carriage 15 is located between the main plate 1 and the Hino-ura support 14,
At the time of needle alignment, the intermediary wheel 12 of the needle turning mechanism is also rotated.

The bottom side of Figure 1 is the electronic circuit section, and the right side is the battery section. The circuit base 21, which serves as an elastic metal plate on which electronic circuit components are placed, is made of nickel silver material, and a thin flexible conductive sheet 25 having a conductive pattern is adhered to the lower surface thereof. The circuit base 21 is placed on the milling part 1j of the base plate 1, and the upper surface of the base plate 1 is at the same height as the upper surface thereof, and is arranged substantially in a plane with the reduction gear train. 22 is a crystal oscillator, 2
3 is an IC chip, 24 is a temperature compensation capacitor,
28 is a trimmer capacitor. The holding structure for the crystal resonator 22 exemplifying the features of the present application is as follows:
The bent portion 21e having a spring force and the bridge 21f provided in the crystal resonator 22 are configured to press and hold the end face of the crystal resonator 22. Temperature compensation capacitor 2
4 is similarly held by the spring force of the bent portion 21i. The trimmer capacitor 28 is connected to the conductive sheet 2
Step part 2 of circuit board 21 which can also bend that part of 5
It is fixed to 1h with solder, and adjustments can be made from the top side by removing the back cover. 21g is conductive sheet 2
5 is also a coil connection portion having the same shape, and presses the coil terminal plate 20 with spring force. 25a is a + lead portion extending to the contact point 26 of the sheet 25, and 25c is a cable in which a conductive pattern of the conductive sheet 25 that does not fit within the plane of the circuit base 21 is provided along the side surface of the crystal resonator 22. Reference numeral 27 denotes a (-) spring of the battery 38, which is fixed by caulking the studs 27a to the circuit base 21. 21c is the circuit base 21
By taking advantage of the fact that the circuit board 21 is made of nickel silver material, the surface of the circuit board 21 is given a mirror finish or has beautiful lines, while the surface of the main board 1 is flat and wide as mentioned above. Since the main plate 1 is spread out, if the surface of the main plate 1 is finished in the same way, the movement can be made to have an extremely high-class feel. The circuit base 21 is fixed to the ground plate 1 with screws 21a and the like, and has the same potential as the (+) potential of the battery 38. Countersinking of screws 21a, etc., mark engraving, surface finishing, maintaining strength as a base,
The circuit base 21 has a spring function due to bending and planar shape, step formation by constriction and bending that allows free design of the height position of the mounted parts, and component bonding strength.
The effect of using metal as the material is significant, and it is possible to consider its use as an electrostatic shield, a function of reinforcing the thin part of the main plate 1, the train wheel bridge 2, the rear wheel bridge 14, etc. Milling section 1j of the main plate 1 in which the circuit board 21 is accommodated
Thick parts 1e, 1f, and 1g are left on the outer periphery of the main plate to match the recesses of the circuit board 21, and these parts come into contact with the inner periphery of the case and have the function of determining the position of the movement. One of the thick parts 1g is provided with a mechanical screw and a dial screw.

FIG. 2 is a sectional view taken along line E-E in FIG.
The circuit base 21 has a shaped portion that matches the outer peripheral side surface of the battery 38, and the spring force of the bent portion 13b allows the battery 3
8 is in contact with the circuit base 21. It is fixed to the base plate 1 by a screw 21j inserted into a counterbore 21b in the vicinity thereof, and assists in positioning the battery 38. Since the circuit base 25 is made of metal, it can be sufficiently fixed with a small pressure contact area such as a countersunk head screw 21j as shown in the figure, and the conductive sheet 25 is attached to the base plate 1.
It is interposed between the circuit board 21 and the circuit board 21, and is held between the base plate 1 and firmly fixed. The temperature compensation capacitor 24 is connected to the circuit board 21
Electrical conduction occurs at the folded portion 25b of the conductive sheet 25 supported by the two-folded portion 21i, and there is an epoxy resin adhesive 24a to supplement the holding function of the capacitor 24 by the clamping force of that portion. The temperature compensation capacitor 24 made of barium titanate material changes its temperature characteristics even when heated with solder, but this structure does not have this problem, and it is possible to solder long lead material to the capacitor body in advance like in the past. There is a significant difference in time and space required for aging and mounting the capacitor on the board compared to soldering the ends of the lead material without applying heat to the capacitor body. In the center of Figure 2,
A bent conductive sheet cable portion 25c is shown passing outside the crystal resonator 22, and its conductive pattern is coated with an insulating coating. A trimmer capacitor 28 is installed in the drawn step 21h of the circuit board 21 which is fixed to the main plate 1 with screws 21k nearby.
is fixed with solder 28h. The position of the stepped portion 21h of the circuit base 21 can be set according to the quasi-trimmer capacitor that is desired to be used commonly in various watches.

FIG. 3 is a sectional view taken along line FF in FIG.
The crystal resonator 22 is mounted by absorbing the length error by the spring force of the bent portion 21e and the bridge portion 21f of the circuit base 21 disposed facing the back cover 39.
A glass 22c is attached to the end of a cylinder 22b made of Kovar material.
The sealed lead plate 22f and the crystal resonator piece 22a
A spring 22e fixed with solder 22g is pressed into the hole 22d' of the ceramic block 22d. Reference numeral 22h is a vacuum sealing stopper made of metal, and it is also possible to change the structure to a structure in which a concave portion is provided and the structure is firmly fixed to the bent portion 21e. The lead plate 22f of the crystal resonator 22 is connected to the conductive sheet 25 with solder 22i. The right side of FIG. 3 shows an IC chip 23 mounted using a flip-chip method.

23a is an epoxy resin coating.
The circuit base 21 is located at approximately the same height as the top surface of the movement.
Since the upper surface of the conductive sheet 25 is set and the conductive sheet 25 is thin, the thickness of the mounting portion is ensured. Also, IC chip 2
Since most of the surface of 3 is covered with the circuit board 21,
This is also effective for shielding the IC chip 23 from light.

〔Effect of the invention〕

As described above, according to the present invention, even if a flexible circuit board is assembled into a watch by itself, it has no strength and will undulate, but by supporting this with a metal plate, a thin flexible circuit board can be used, and the watch can be made thinner. In addition, since the flexible circuit board is fixed through the metal plate, the conductive sheet can be fixed with a small pressure contact area, and the hoop production, which is possible with thin circuit boards, helps reduce the cost of circuit blocks. becomes possible. Furthermore, since almost the entire IC chip is covered with a metal plate, it is effective in shielding the IC chip from light, and the circuit board is set within the thickness of the movement to maximize the space in the thickness direction, making it possible to protect the IC chip from light. It can also facilitate implementation.

In addition, by using the elastic force of the elastic metal plate to hold other parts on the elastic metal plate, a separate holding member for holding the parts can be omitted, and furthermore, the elastic metal plate and the flexible circuit board can be If it is fixed, the elastic metal plate can hold large electronic parts such as crystal oscillators with a strong holding force, and the circuit board can be connected for continuity, such as by soldering, etc. Furthermore, by placing the elastic metal plate facing the back cover, it is possible to create a pattern that gives it a sense of luxury.For example, even if the back cover is not made of metal, the elastic metal plate can be used. Since it is made of metal, it can provide electrostatic shielding, and it also has great effects on making watches easier to disassemble and assemble, and making watches thinner, smaller, and cheaper.

[Brief explanation of drawings]

FIG. 1 is a plan view of a crystal oscillation wristwatch according to an embodiment of the present invention, FIG. 2 is a cross-sectional view taken along line E-E in FIG. 1, and FIG. 3 is a cross-sectional view taken along line F-F in FIG. . 1...Main plate, 3...Second wheel, 4...Third wheel, 5
... Fourth wheel, 6... Rotor, 21... Circuit base,
21e, 21f...Bending portion, 21i...Bending portion, 22...Crystal resonator, 24...Temperature compensation capacitor, 25...Flexible conductive sheet.

Claims (1)

[Claims] 1 Consisting of a flexible circuit board in which a conductive pattern is formed on a thin plastic sheet, an elastic metal plate having a size and shape that can cover most of the flexible circuit board, a base plate, and the base plate and the circuit board. The elastic metal plate faces the watch back cover and is approximately at the same height as one surface of the back cover side that determines the main thickness direction of the front watch movement. In this case, the flexible circuit board is electrically connected to have the same potential as one of the batteries, and the flexible circuit board is interposed between the base plate and the elastic metal plate, and the flexible circuit board is interposed between the base plate and the elastic metal plate. The elastic metal plate is fixed to the base plate by fastening means such as screws, and the elastic metal plate is formed with an elastic holding portion that holds at least a part of the electronic component by the pressing force due to the elasticity of the elastic metal plate. An electronic wristwatch.