JPS6015904B2 - crystal clock - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a quartz watch that uses a quartz oscillator as a time standard, which does not have any other special frequency adjustment means, by adjusting the resonant frequency to a predetermined frequency using a laser beam.

Traditionally, crystal watches have used a crystal resonator as a time standard, but have also used variable pull capacitors or step variable capacitors to adjust the time. Although this did require the resonant frequency of the crystal resonator to be adjusted to a constant value, the error range was widened and manufacturing costs were reduced. However, on the other hand, it requires additional items such as variable capacitors and step variable capacitors, which increases the cost and space.
Moreover, changes in this additive caused a decrease in the accuracy of the time standard. The present invention provides an inexpensive and compact quartz watch that reduces the manufacturing cost of the crystal resonator itself and eliminates special means for adjusting time (such as the variable capacitor or step variable capacitor described above). .

The invention will now be explained in more detail with reference to the drawings.

FIG. 1 shows an example of a crystal oscillator circuit that produces standard time used in the present invention. lm is an amplifier made of C-MOS, X' is a crystal oscillator, Cd is a resistor Rd connected to the drain side of the amplifier lm, and is a resistor for improving the voltage characteristics of the oscillation frequency. There are various ways to make X'tal,
A tuning fork type crystal resonator shown in FIG. 2 is used here. A tuning fork shape is punched out using photo-etching technology from a quartz plate with a thickness of 0.2 or less.

A Z plate is used as the crystal plate, and the rotation angle from the Y axis is ±10.
If the value is within 0, the zero temperature coefficient temperature can be placed in the range of 1C to 35Qo, which is convenient. Because it is extremely thin, electrodes cannot be built into the thick side, and it has the electrode structure shown in FIG. 3. 1 and 2 are electrodes, and the crystal oscillator
Also on the back side of 'tal, 1' and 2' are symmetrically attached by photoetching the deposited film. The electric field is electrodes 1, 2, 1
',2' and excites the crystal resonator x'tal. 5 and 6 are weights made of vapor-deposited films, and by removing part or all of them using a laser beam, the resonant frequency of the resonator x' is kept at a constant value within an error of at least 0.9 sand/ship y. It can be arranged.

Reference numerals 3, 4, 3', and 4' are connecting portions that also serve as electrode leads and are attached to the base 7 as shown in FIG.

Other variations in the electrode structure of the crystal resonator are possible. FIG. 4 shows an example of how to attach the crystal resonator x'ta to the base. The base 7 is made of quartz material, has thin films 8 and 9, and is fixedly connected to the connecting parts 3' and 4' of the resonator x'PI by solder. Furthermore, the electrodes are drawn out to the outside by lead wires 11 and 12. The crystal resonator shown in FIG. 4 is vacuum-sealed in a ceramic case or a metal case having a partially transparent body. The transparent part is Xtal
It is positioned above the tip portions 5 and 6 of the laser beam, and a laser beam is applied through the transparent portion to remove the portions 5 and 6. Furthermore, the oscillation circuit shown in FIG. 1, a frequency dividing circuit for pdowning the signal from the oscillation circuit to S, and a drive circuit for driving means for displaying time are integrated, and an IC is integrated into one chip. The crystal resonator ×'t
It is enclosed at the same time as al. Let's discuss how to obtain the necessary frequency limit when incorporating the frequency of the time standard part surrounding this crystal oscillator into a clock. First, before the Xtal resonator shown in Figure 4 as a rough tuning is vacuum sealed in the case,
The necessary connections are connected to the oscillation circuit shown in Figure 1, and the oscillation frequency of this oscillation circuit is set to -1 min/min with a laser beam.
Remove the tip weight so that the time error is less than day. Next, the case is vacuum-sealed, and a laser beam is used to pass the tip weight of the crystal resonator Remove by irradiating. If you repeat this tuning operation not once but several times, you can reduce the time error by ±
It is ensured that the amount of sand is 0.9 sand/ship y or less. Various other methods other than the one shown in FIG. 4 are conceivable for connecting and supporting the crystal resonator and the case. FIG. 5 shows another specific example, in which the crystal resonator x'tal is connected and supported by a spring 13 to the case. In this case, the electrodes 1 and 2 shown in FIG. 4 are attached only to one side (upper surface). Although the input impedance of the crystal is high,
Because it is supported by spring material, it has excellent earthquake resistance and impact resistance. FIG. 6 shows another specific example, in which two spring members 1
It is connected to the case at 4 and 15. It is effective in cases where the temperature expansion coefficient is different from that of the crystal resonator, such as in a ceramic case, and for taking out lead wires.Furthermore, since it is attached with a spring material, the advantages of Figs. 4 and 5 are utilized. Although the oscillation circuit is of course not limited to that shown in FIG. 1, it will be further explained using FIG.

All of the components shown in FIG. 1 can be integrated into one chip.
Of course, it is possible to remove the capacitors Cg and Cd, but
The case will be discussed later. Figure 7 shows the power consumption curve of Figure 1, with the values of capacitors Cg and Cd taken as the axis,
Power consumption is plotted on the vertical axis. FIG. 8 shows the oscillation start voltage Ps. FIG. 9 shows the deviation of the oscillation frequency by the same voltage. As can be seen from the curves in FIGS. 7, 8, and 9, it can be seen that the capacitors Cg and Cd have optimal values rather than being freely selected. As a result of coupling the manufactured crystal oscillator and oscillation circuit, if the oscillation frequency is matched with a laser beam to the optimum value, only the IC chip and the crystal oscillator are required, so excellent aging results can be obtained. Stable oscillation operation can be expected, and furthermore, the conditions for the oscillation circuit can be relaxed. Furthermore, since the electronic circuit and the crystal resonator are housed in one case, there is no need for a special board for wiring, resulting in a very small space and low cost. Let's discuss the advantages of removing capacitors Cg and Cd.

Of course, as mentioned above, the optimum value is selected. but,
Since the crystal resonator shown in Figure 3 is 4-type when touched, it is inevitable that the impedance will be high, so even if you change the value of capacitor Cg or Cd to speed up the time, it will only take a few seconds at most. It's nothing more than that. Therefore, the conventional method has been to use a variable capacitor as the capacitor Cg to adjust the time, but the reality is that it is difficult to correct the temperature characteristics with this method. Therefore,
In the present invention, the oscillation frequency is changed for temperature correction, in other words, the above-mentioned
By using a range of several seconds at most and making one or both of the capacitors Cg and Cd with a temperature variable element, such as a titanium sambarium capacitor, it is possible to improve the temperature characteristics of the crystal resonator depending on the temperature. As described above, according to the present invention, a tuning fork crystal oscillator whose inflection point of temperature frequency characteristics has been brought to room temperature (2000) by a new solar angle and a new electrode arrangement is used, and a tuning fork crystal oscillator with a frequency adjustment point at its tip is used. A weight is installed and the IC chip is sealed in a partially transparent container, and then the frequency of the tuning fork crystal resonator is adjusted by removing the weight with a laser beam at room temperature. The fact that the IC chip is stable and that the IC chip is sealed in the same container as the vibrator makes it possible to provide a highly accurate and stable frequency.

[Brief explanation of the drawing]

FIG. 1 is a circuit diagram of a conventionally used oscillation circuit, and FIG. 2 is a perspective view showing the cut angle of a resonator used in the present invention.
Figure 3 is a plan view of the resonator shown in Figure 2 with electrodes arranged;
5 and 6 are perspective views of embodiments showing the mounting structure of a resonator used in the present invention, and FIGS. 7, 8, and 9 are oscillation circuits used in the present invention, respectively. 7 is a graph showing the power consumption, FIG. 8 is a graph showing the oscillation start voltage, and FIG. 9 is a graph showing the voltage characteristics. X'tal...Crystal resonator, Cd, Cg...
・Output of the inverter lm of the oscillation circuit, capacitor attached to the input side, 1, 2... Electrodes, 3, 4...
... Connection portion, 5, 6 ... Weight, 7 ... Crystal base, 13, 14, 15 ... Spring support material. Many figures, two figures, three figures, a four figures, many figures, five figures *7 figures, many figures, 91 army tagawabe

Claims (1)

[Claims] 1. In an electronic watch that has an oscillator including a crystal oscillator as a time standard, the crystal oscillator is cut out from a quartz plate by rotating a Z plate within a range of ±10 degrees around the Y axis. A tuning fork type crystal resonator formed by photo etching, the tuning fork type crystal resonator having an electrode pair formed between an electrode extending along the center part and an electrode extending along the peripheral part in separate forks. The IC chip, which includes the tuning fork crystal resonator and the oscillation circuit, is enclosed in a transparent container at least in part, and the laser beam is used to illuminate the container. A crystal watch characterized in that a frequency adjustment weight that is removed from the outside is provided at the tip of each of the tuning fork type crystal oscillators.