JPS6013155B2 - Crystal clock motor drive circuit - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a motor drive circuit for a quartz watch.

Conventionally, in the motor drive circuit of a quartz watch, the crystal oscillator, load capacitor, and oscillation integrated circuit are each independent, so even if the frequency of the crystal oscillator is adjusted, it is difficult to attach each component to the circuit board. The oscillation frequency shifts due to the influence of stray capacitance.

Furthermore, even when a capacitor is formed on a crystal resonator, in the case where the crystal drive electrode is partially exposed (for example, Hakama Kosho No. 41-9041), when the capacitor is sealed with a metal cap, the exposed drive electrode is The electrode and the cap are capacitively coupled, and the stray capacitance varies depending on the mutual positional relationship between the electrode position and the metal cap position, so that the oscillation frequency shifts. Therefore, it was necessary to insert a trimmer capacitor to adjust the frequency. The present invention aims to eliminate the above-mentioned drawbacks of the prior art and provide a crystal oscillator in which there is almost no deviation in oscillation frequency after frequency adjustment. An embodiment of the present invention will be described based on the drawings. As shown in FIG. The terminal pin 4 is electrically conductive to this metal base.

A circuit board 6 is fixed on the base 1. As shown in the second diagram, circuit patterns 6a, 6b, 6c, 6d, and 6e are formed on the surface of the circuit board 6, and the terminal pins 3; 4 are also electrically connected to the patterns 6a, 6c. An integrated circuit piece (IC chip) 7 is die-bonded to the center of the circuit board 6, and each circuit element of this IC chip and each pattern 6a to 6e are electrically connected by wire bonding. Furthermore, patterns 6a and 6b
, 6c, the upper ends of the terminal pins 3, 4, and 5 are inserted into the terminal pins 3, 4, and 5, and are fixed to each other in an electrically conductive state. As shown in the third figure, the lower ends of conductive holding springs 8 and 9 are firmly attached to the heads of the terminal pins 3 and 4 which are located opposite each other. Holding spring 8
, 9 hold the crystal resonator 10 horizontally with a gap between it and the circuit board 6. Load capacitance is formed on both sides of the crystal resonator 10, and this configuration is shown in FIGS. 4A and 4.
This will be explained with reference to FIGS. B to 6A and FIG. 68. Note that FIGS. 4A to 6A represent the front surface, and FIGS. 4B to 6B represent the back surfaces inverted with the vertical center line of FIGS. 4A to 6A as axis 0, respectively. First, on both the front and back surfaces of the crystal resonator 10, the drive electrode film 12, the noble metal 3, and the respective lead-out exposure electrodes 2a and 13a are formed by vapor-depositing silver, nickel, etc.
Figure B).

Next, on the upper surface of each drive electrode film head 2, 13, a dielectric film 14, a shell 5 is formed by vapor deposition of silicon monoxide or the like so as to completely cover the drive electrode film (FIG. 5A,
Figure 5B). Furthermore, outer electrode films (earth electrode films) 16 and 17 and lead-out electrodes 6a and 7a are deposited to prevent short circuits with the drive electrode film 12 and the part 3 (sixth electrode film).
Figure A, Figure 6B). Furthermore, the outer electrode film 16? As long as there is continuity, the film thickness may be very thin.In this way, each paper consisting of the drive electrode films 6, 17, the dielectric film 4, 15, the outer electrode film 16, and the wire 7 A load capacitance of 0 is generated by the crystal oscillator.

A crystal oscillator with a load capacity of the above configuration,
Extracting electrodes 12a and turtle 3 of drive electrode films 12 and 13 on both sides
a is connected to the connection spring groups 8 and 19 using conductive adhesive, and this connection spring is connected to the patterns 6d9 to 6e of the circuit board 6.
is electrically connected to. Furthermore, the extraction electrode groups 6a, 17a of the outer electrode films 16, 17 of the crystal oscillator turtle 0 are pulled out in the same direction, and are electrically connected to the circuit patterns 6a, 6c of the circuit board 6 via the conductive holding spring 9. Connected.
The lower end of the metal cap 20 is iron-fitted to the metal base turtle, thereby hermetically sealing the circuit board 6 and the crystal resonator 10. Next, the electrical connection state of the present invention will be explained with reference to the equivalent circuit diagram shown in FIG.

The terminal pin 5 is an output terminal for clock driving, and is connected to the clock driving circuit 21 of the IC chip through the circuit pattern 6c of the circuit board 6. 22 is a frequency dividing circuit, 23 is a buffer, 24 is an amplifier.

It is connected to the outer electrode film 16 and the oven 7 via the pin 4. Note that since the holding spring 9 is electrically connected to the metal cap 20 via the terminal pin 4 and the metal base 1, the crystal resonator 10 and the metal cap are at the same potential. Terminal pin 3 is a power terminal, and in this case is in a negative state. Next, the driving state of the timepiece by the crystal oscillator according to the present invention will be explained with reference to FIG. A capacitor 2 is connected to the drive coil 25 of the inductor motor M.
6 is directly connected to the IC chip T, and a DC power supply 27 is connected in series to this series circuit via a switching circuit in the drive circuit 21 of the IC chip T. Therefore, current flows in one direction through the drive coil 25 and charges the capacitor 26, and by switching the switching circuit, the capacitor is discharged and current flows in the other direction through the drive coil. In this way, the driving inductor motor M rotates. In the present invention having the above configuration, the load capacitance is formed in the crystal oscillator and hermetically sealed together with the driving integrated circuit in one cap. Because of this, no stray capacitance occurs in relation to the installation position of the crystal resonator within the metal cap.

Therefore, there is no deviation in oscillation frequency. Since the area of the load capacitor can be widened, the capacitance can be increased, and since it is hermetically sealed, the load capacitance is not affected by humidity, resulting in high reliability, and there is no need for an external trimmer capacitor for frequency adjustment. In addition, because the integrated circuit is die-bonded to the circuit board, even if the integrated circuit is defective, the base can be reused by removing the circuit board, and the pattern on the circuit board can be formed close to the integrated circuit, so autobonder
Recruitment becomes easier. In addition, the capped base can be sealed with cold weld or resistance welding, increasing the reliability of the finished product. Also, since there are very few parts, it is extremely easy to assemble and has excellent workability.

[Brief explanation of drawings]

The drawings show an embodiment of the present invention, and FIG. 1 is a sectional view;
Figure 2 is a plan view of the circuit board, Figure 3 is a plan view with the cap omitted in Figure 4, Figures 4A and 6A and 6B are the order of deposition of load capacitance on the crystal resonator. FIG. 7 is an equivalent circuit diagram, and FIG. 8 is a wiring diagram of the drive circuit of the Isodo motor. 1...Metal base, 3, 4...Power terminal, 5...Output terminal for clock drive, 6...Circuit board, 6a to 6e... Circuit pattern, 7...
...Integrated circuit, 8,9...Holding spring, 10...Crystal resonator, 11...Load capacity, 12,13...
... Drive electrode film, 14, 15... Dielectric film, 16,
17...Outer electrode film, 18, 19... Connection spring, 2
0...Metal cap. Lacquer 1 drawing*2 Box drawing 3 drawing 4A drawing Tsutomu 48 drawing Tsutomu 5A drawing 58 drawing 8A drawing 68 drawing Mazu drawing 8 drawing

Claims (1)

[Claims] 1. A crystal resonator is sealed in a sealed container with a metal cap fitted to the base via a plurality of retaining springs, and a drive unit formed at the center of both sides of the crystal resonator. A dielectric film and an electrode film are sequentially deposited to completely cover each of the electrode films, and each set of the drive electrode film, dielectric film, and outer electrode film increases the load capacity of the crystal resonator. and the outer electrode films of each set are short-circuited by one of the retaining springs, a circuit board on which an integrated circuit piece is mounted is placed on the base, and an appropriate one of the circuit patterns of the circuit board is placed on the base. Two connection springs fixed to something,
It is connected to each of the drive electrode films. A motor drive circuit for a crystal clock characterized by: