JPS6221067Y2 - - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to an ultra-thin crystal oscillator mainly used in a crystal oscillation type electronic wristwatch.

The purpose of the present invention is to provide an ultra-thin crystal oscillator.

Another object of the present invention is to provide a crystal oscillator that is inexpensive and highly reliable.

BACKGROUND ART In recent years, as wristwatches have become thinner due to demands for greater fashionability, crystal oscillators used in crystal oscillation type electronic wristwatches have been desired to be thinner. Furthermore, with the spread of crystal oscillation type electronic wristwatches, the demand for lower prices and higher reliability of crystal oscillators has further increased. However, conventional crystal oscillators do not fully satisfy this requirement. In particular, the thickness of crystal oscillators is usually 2m/m to 3m/m, and the thickness of crystal oscillator electronic watches is One of the reasons why it is thicker than a clock is the thickness of this crystal oscillator.

FIG. 1 shows an example of a conventional crystal oscillator using two metal cases, with FIG. 1A showing a plan view and FIG. 1B showing a front sectional view. Reference numeral 1 indicates a crystal oscillator piece formed by corrosion removal processing, and reference numerals 2 and 3 indicate metal cases, which are vacuum-sealed by cold pressure welding, welding, or the like. 4 and 5 are lead wires for taking out the two electrodes of the crystal oscillation piece to the outside of the case and fixedly supporting the crystal oscillation piece; 6 is a glass 7 for electrical insulation and vacuum sealing between the lead wires; and the stem is brazed to the case 2.

The crystal oscillator in this example has the following drawbacks.

1. In order to guarantee the airtightness of the stem, it is necessary to make the stem long, and it is difficult to make it thinner.

2 The fixing part of the lead wire that fixes the crystal oscillation piece is
Satisfactory planar accuracy cannot be obtained during processing, and the crystal oscillator piece tends to be tilted in the thickness direction. Therefore, a free space is required to avoid collision with the case, and it is difficult to make the device thinner.

3. When fixing a crystal oscillator piece to a lead wire, distortion occurs due to differences in thermal expansion coefficients, and frequency shifts are likely to occur due to disturbances when dropped.

4.Manufacturing costs are high due to the large number of parts.

Further, FIG. 2 shows an example of a conventional crystal oscillator using a cylindrical metal case, with FIG. 2A showing a plan sectional view and FIG. 2B showing a front sectional view. 1 is a crystal oscillation piece, 8 is a cylindrical metal case, 9 and 10 are lead wires for taking out the two electrodes of the crystal oscillation piece to the outside of the case and fixing the crystal oscillation piece, and 11 is a line between the lead wires. The stem has a glass 12 for electrical insulation and vacuum sealing, and the stem is vacuum sealed with the case by a method such as press fitting or welding.

The crystal oscillator in this example has the following drawbacks.

1. In order to reduce the outer diameter of the metal case, it is necessary to downsize the crystal oscillator piece, or it is difficult to make the crystal oscillator thinner because making it thinner directly leads to a decrease in performance.

2 When fixing the crystal oscillation piece to the lead wire, even if there is a slight inclination between the stem and case and the crystal oscillation piece with respect to the plane direction of the crystal oscillation piece, the end of the arm of the crystal oscillation piece will not collide with the case. Therefore, a free space is required to prevent the two from colliding, making it difficult to reduce the thickness.

3. When fixing the crystal oscillator piece to the lead wire, distortion occurs due to the difference in coefficient of thermal expansion, and therefore frequency shifts are likely to occur due to external disturbances such as dropping.

Also, Figure 3 shows another example of a conventional crystal oscillator.
The case uses a three-layer laminated ceramic plate and a glass plate, and Figure 3A is a plan cross-sectional view;
Figure B shows a front sectional view. 1 is a crystal oscillation piece, 13
14 is a first layer ceramic plate, 14 is a second layer ceramic plate, 15 is a third layer ceramic plate, and between the second and third layer ceramic plates are thick film electrode patterns 16 and 17 made of conductive paste. is formed, and a crystal oscillation piece is fixedly supported on the thick film electrode pattern. Further, 18 is a glass plate, and the glass plate is vacuum-sealed with a third layer of ceramic plate using an airtight adhesive material.

The crystal oscillator in this example has the following drawbacks.

1. In order to maintain the airtightness of a ceramic case, it is difficult to make it thinner.

2. When fixing the crystal oscillator piece on the thick film electrode pattern, the third layer of ceramic plate gets in the way, making it impossible to control the inclination of the crystal oscillator piece in the thickness direction. A free space is required between the two, which hinders thinning.

3. Frequency shifts are likely to occur due to disturbances such as dropping due to distortion due to the difference in thermal expansion coefficients between the crystal oscillator piece and the ceramic plate.

As mentioned above, the common drawbacks of conventional crystal oscillators are that it is difficult to make them thin and that distortion occurs in the fixed part of the crystal oscillator piece, reducing reliability.The present invention solves these drawbacks. is removed completely,
An embodiment of the present invention is shown in FIGS. 4 and 5. FIG. 4 is a front sectional view of this example, and FIG. 5 is an exploded perspective view of this example. In FIG. 4, the piezoelectric oscillator of the present invention includes a flat crystal oscillating piece 19, and the crystal oscillating piece 1.
a crystal frame 20 in which 9 is fixedly supported by face-to-face contact;
A plate body 21 joined to the crystal frame 20, and the crystal frame 2
0 and a lid body 22 joined to the crystal frame 20.
is a plane 20 on which the crystal oscillation piece 19 is fixedly supported.
a and the lid body 2 which is on the same plane as the plane 20a.
The plate body 21 is made of a crystal plate or a metal plate, and the lid body 22 is made of metal. It is characterized by the above configuration.

In FIGS. 4 and 5, two electrodes (not shown) on the crystal oscillation piece are fixedly supported by the crystal frame 20, so that one electrode can be connected to the crystal from the electrically conductive portion 23 on the crystal frame. The plate body 21 is connected to the plate body 21 through the electrically conductive portion 25 on the plate body 21 through the side surface of the hole 20c of the frame.
The other electrode is taken out to the lid 22 through the electrically conductive portion 24 on the crystal frame 20.

In addition, the crystal oscillator piece, crystal frame, plate,
The lid is formed by corrosion removal processing to make it thinner.

As described above, according to the present invention, the following advantages can be obtained.

(1) Since the crystal resonator, plate body, and crystal frame use the same crystal material, it is not doped with other ions and is highly reliable without contamination even after long-term use.

(2) Since there are no holes drilled in the plate or crystal frame for the contacts, the cost is reduced, and since the contacts do not require low-melting glass, high airtightness can be maintained over a long period of time.

(3) Since the conductive part can also be obtained on the bottom surface of the plate and the metal lid, there is flexibility in securing space as a small component.

(4) Since the crystal oscillator piece and the crystal frame that fixes and supports the crystal oscillator piece have the same coefficient of thermal expansion, even when fixed by surface bonding, almost no distortion due to thermal stress occurs, improving long-term reliability.

(5) The base plane of the tuning fork type crystal oscillator piece is fixed by surface bonding to a crystal frame whose both planes are parallel, and a plate is joined to one side of the crystal frame, and a lid is attached to the other side. Since the crystal resonators are joined together, it is possible to easily maintain the parallelism of the vibrating layer and the plate body with respect to the crystal frame, making it possible to manufacture and provide highly airtight, thin crystal resonators.

[Brief explanation of the drawing]

FIG. 1, FIG. 2, and FIG. 3 are diagrams showing conventional examples of crystal oscillators. FIG. 4 and FIG. 5 are diagrams showing an embodiment of the present invention. 19 is a crystal oscillation piece, 20 is a crystal frame, 21 is a plate, 22 is a lid, and 23, 24, and 25 are electrically conductive parts.

Claims (1)

[Scope of utility model registration request] A flat tuning fork type crystal oscillation piece and both planes are formed parallel to each other, the tuning fork type crystal oscillation piece is fixedly supported by surface bonding, and two electrodes connected to the crystal oscillation piece are surface bonded. A crystal frame disposed on the surface, a plate member connected to one side of the crystal frame, and a lid body connected to the other side of the crystal frame, and the crystal frame is connected to the tuning fork type crystal oscillator piece. It consists of a plane on which the base is fixedly supported, a sealing joint surface with the lid formed on the plane, and a hole facing the tuning fork part of the tuning fork type crystal oscillation piece and serving as a vibration space, The plate body is formed from a crystal plate, the lid body is formed from metal, one of the electrodes provided on the crystal frame is arranged circumferentially around the crystal frame, and the other electrode is arranged around the crystal frame. Through the inner circumference of the frame,
A crystal oscillator, characterized in that the crystal oscillator is connected to an outer lower surface of the plate through an upper surface and an outer peripheral side surface.