JPH0642616B2 - Crystal oscillator - Google Patents

Description

TECHNICAL FIELD The present invention relates to a thickness-shearing quartz crystal resonator.

(Prior Art) A conventional thickness-sliding quartz crystal resonator is shown in FIG.

Electrodes 3a and 3b are provided substantially in the center of the front surface and the back surface of the disk-shaped crystal diaphragm 2, the electrode 3a on the surface contacts one end of the circumference of the crystal diaphragm 2, and the electrode 3a on the back surface is the crystal. It is in contact with the other end of the circumference of the diaphragm 2.

Then, one end of the circumference of the crystal vibrating plate 2 in contact with the electrode 3 a on the front surface and the other end in contact with the electrode 3 b on the back surface are formed into a pair of metal plate springs provided on the airtight terminal 7. The holders 6a and 6b are sandwiched and held in the slits, and the sandwiched portions are held by the epoxy-based conductive paste 8
They are fixed by a and 8b respectively.

(Problems to be Solved by the Invention) The epoxy conductive paste for fixing the crystal diaphragm to the holder has a pencil hardness of 2 to 3H after curing. For this reason, the Q value of the thickness-sliding mechanical vibration system of the quartz crystal diaphragm is lowered and the electrical resistance is also increased.

Further, even with respect to shock, the shock is directly applied to the crystal diaphragm without being shock-absorbed at the fixed part, and thus the fixed part and the electrode part are often cracked or the crystal itself is damaged.

Therefore, in the present invention, by using a flexible silicon-based conductive paste, the Q value is high and the electrical resistance is low.
It is an object to provide a crystal unit that is resistant to impact.

(Means for Solving the Problems) As means for achieving the above object, a quartz diaphragm having electrodes on both sides, a holder for holding the quartz diaphragm, electrodes for the quartz diaphragm, and a holder. And a conductive paste obtained by mixing flaky silver powder hardened on a silicon-modified resin in a weight ratio of 60% to 80% as the conductive paste. The present invention is intended to provide a crystal unit characterized by being used.

(Example) FIG. 1 shows an example of the crystal resonator of the present invention.

Electrodes 3a and 3b are provided substantially in the center of the front surface and the back surface of the disk-shaped crystal diaphragm 2, the electrode 3a on the surface contacts one end of the circumference of the crystal diaphragm 2, and the electrode 3a on the back surface is the crystal. It is in contact with the other end of the circumference of the diaphragm 2.

The holder 4a is in contact with one end of the circumference of the crystal diaphragm 2 with which the front surface electrode 3a is in contact, and the rear surface electrode 3
The retainer 4b is in contact with the other end with which b is in contact.

At the contact points where the electrodes 3a, 3b and the holders 4a, 4b are in contact with each other, the surface electrode 3a and the holder 4a are fixed with a silicon-based conductive paste 5a, and similarly the surface electrode 3b and the holder 4b are fixed. It is fixed with the silicon-based conductive paste 5b.

The silicon-based conductive pastes 5a and 5b are more flexible than the epoxy-based conductive pastes 8a and 8b, and the epoxy-based conductive pastes 8a and 8b have a pencil hardness of about 2 to 3H. In contrast, the silicon-based conductive pastes 5a and 5b can have a pencil hardness of about 5 to 7B.

Therefore, as shown in the figure, the crystal diaphragm 2 and the cages 5a, 5
Even if the contact area with b is reduced, since the silicon-based conductive pastes 5a and 5b in the fixed portion have flexibility, cracks do not occur. Further, since the degree of freedom of the thickness shear vibration of the crystal diaphragm 2 is increased, the Q value is also improved. Further, even if a shock is applied from the outside, the silicon-based conductive pastes 5a and 5b in the fixed portion absorb the shock, so that the crystal diaphragm 2 and the electrodes 3a and 3b can be prevented from being damaged.

Further, as shown in FIG. 2, the silicon-based conductive pastes 5a and 5b can be used for the crystal resonator 1b having the same shape as the conventional one.

That is, the electrodes 3a and 3b are provided substantially in the center of the front surface and the back surface of the disk-shaped crystal diaphragm 2, and the electrode 3a on this surface contacts one end of the circumference of the crystal diaphragm 2 and the electrode 3a on the back surface. Is in contact with the other end of the circumference of the crystal diaphragm 2.

Then, one end of the circumference of the crystal vibrating plate 2 in contact with the electrode 3 a on the front surface and the other end in contact with the electrode 3 b on the back surface are formed into a pair of metal plate springs provided on the airtight terminal 7. The holders 6a and 6b are sandwiched and held in the slits, and the sandwiched portions are held by the silicon-based conductive paste 5
They are fixed by a and 5b respectively.

Even in this case, the impact resistance and the Q value are improved as compared with the case where the epoxy-based conductive pastes 8a and 8b are used.

Next, the characteristics of the silicon-based conductive pastes 5a and 5b will be described below.

[Experiment 1] In order to impart conductivity to flexible silicon, it is optimal to mix silver. Therefore, 1a of a crystal resonator using a conductive paste having a different silver content ratio is used. 2 each
Zero of them were prepared, their impedances were measured, and their variations and average values are shown in FIG.

The crystal unit 1a used in this experiment has a model name of H
C-49 / u, blank diameter 8.9 mm, oscillation frequency 4.0
MHz.

From the graph of FIG. 3, when the silver content exceeds 60%, the variation in impedance is extremely reduced, and the average value of impedance is the lowest in the range of 60 to 80% and 16 to 2
You can see that it is 1Ω.

In the case of the crystal resonator 1c using the epoxy-based conductive pastes 8a and 8b, the impedance variation is larger than that of the crystal resonator 1a using the silicon-based conductive paste, and the silver content is 70% to 90%. The average value of the impedance in each is about 30Ω, and is 16 to 21 of the crystal unit 1a using the silicon-based conductive paste.
It becomes a value larger than Ω.

[Experiment 2] Next, a crystal oscillator 1a using a silicon-based conductive paste having a silver content of 60%, 70%, and 80% and an epoxy-based conductive paste having a silver content of 70% was used. Two
The drop impact strength was examined by dropping 0 pieces each on a 5 mmt bake plate while changing the height and measuring the damage rate at that height. The result is shown in FIG.

The crystal unit 1a used in this experiment has a model name of H
C-49 / u, blank diameter 8.0mm, oscillation frequency 19MH
z's.

According to the graph of FIG. 4, the drop impact strength of the silicon conductive paste is stronger than that of the epoxy conductive paste.
Also, it is understood that the smaller the content of silver, the stronger.

From the experimental results of [Experiment 1] and [Experiment 2], it is found that the crystal oscillator using the silicon-based conductive paste containing silver in a weight ratio of 60% to 80% is the best.

(Effects of the Invention) Since the crystal resonator of the present invention uses the silicon-based conductive paste in which silver is mixed in a weight ratio of 60% to 80%,
Since the degree of freedom of thickness-shear vibration of the crystal diaphragm 2 increases and the impedance also decreases, it is possible to provide a crystal resonator having a high Q value.

Furthermore, since the fixed part itself is flexible, not only is it difficult for cracks to occur in the fixed part, but also when an impact is applied from the outside,
Since the silicon-based conductive paste in the fixed portion absorbs the shock, it is possible to prevent damage to the crystal diaphragm and the electrodes, and thus it is possible to provide a crystal resonator resistant to shock.

[Brief description of drawings]

FIG. 1 is a perspective view showing an embodiment of the crystal unit of the invention,
FIG. 2 is a plan view showing another embodiment of the present invention, FIG. 3 is a graph showing the silver content of the silicon-based conductive paste and the impedance characteristics of the crystal unit, and FIG. 4 is the silver of the conductive paste. Fig. 5 is a graph showing the characteristics of the content and the drop impact strength of the crystal unit, and Fig. 5 is a plan view showing a conventional example. 1a, 1b, 1c ... Crystal oscillator, 2 ... Crystal diaphragm, 3a, 3b ... Electrode, 4a, 4b, 6a, 6b ... Retainer, 5a, 5b ... Silicon-based conductive paste, 7 ... Airtight terminal, 8a, 8b ... Epoxy conductive paste.

Claims (1)

[Claims] 1. A crystal resonator comprising a crystal vibrating plate having electrodes on both sides, a holder for holding the crystal vibrating plate, and a conductive paste for fixing the electrode and the holder of the crystal vibrating plate. A crystal resonator, wherein the conductive paste is a conductive paste obtained by mixing flaky silver powder cured in a silicon-modified resin at a weight ratio of 60% to 80%.