JPS5871708A - Container of crystal oscillator - Google Patents

Abstract

PURPOSE:To obtain a miniaturized, thin and flat crystal oscillator, by using a crystal plate to at least one of a supporting case which is half-etched with double stages and a cover body of the flat crystal oscillator. CONSTITUTION:A supporting case 7 is made of a crystal plate and half-etched with double stages. Thus the double-stage half-etching is possible with a large etching factor and high precision. This can reduce the size and thickness of a flat crystal oscillator. While a cover body 5 is made of a flat plate of a metal or glass. This improves the precision of a sealing surface. As a result, the yield is improved for the airtight sealing.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a material for a flat crystal resonator container.

In recent years, the demand for small, thin crystal wristwatches has increased, and along with this, there has been a growing demand for smaller and thinner crystal units.

Figures 1 and 2 are cross-sectional views of a flat type crystal resonator.
The figure shows a first conventional example, and FIG. 2 shows a second conventional example in which the support case is etched in two stages.

Conventionally, a flat, small, thin crystal resonator as shown in FIG. 1 has been used. In FIG. 1, a support case 1 has a concave portion 1a formed on a glass plate by half etching. A crystal piece 2 is fixed to the upper surface 1b of the recess 1a, and the crystal piece 2 is hermetically sealed by the lid 3&C.

In order to meet the demand for further thinning of such a structure, it is necessary to make the support case 1 thinner. In order to make the support case 1 thinner, it is necessary to reduce the thickness of the glass plate that is its material.

However, in the case of glass, it is currently relatively easy to process glass up to a thickness of about 0.5 mm, but when the thickness decreases to 0.3 mm or less, the processing technology becomes extremely difficult and costs increase. Furthermore, even if thin glass could be used, the yield would suffer because many of the glasses would warp or break due to the effects of heat during the buttering process during the manufacturing process of the support case.

For this reason, it has been difficult to reduce the thickness of flat crystal resonators.

Furthermore, in the case of the crystal resonator having the configuration shown in FIG. 1, the lid 6 is made of metal by stamping and pressing, so the surface precision of the sealing surface 6a of the lid 6 deteriorates, making airtight sealing difficult and reducing yield. It also had the disadvantage of decreasing.

In order to improve the drawbacks of the conventional example shown in FIG. 1, a flat type crystal resonator shown in FIG. 2 was used as a second conventional example.

In FIG. 2, the support case 4 is a so-called two-stage half-etched glass plate in which a first recess 4a is formed by first half-etching and a second recess 4b is formed by second half-etching.

Reference numeral 5 denotes a flat plate lid made of metal or glass, which has a structure in which the crystal piece 2 is fixed to the upper surface 4C of the first recess 4a and then hermetically sealed with the lid 5. This two-stage half-etching manufacturing method has made it possible to make the glass material of the support case 4 relatively thick, making it possible to make crystal resonators thinner, but it has been difficult to make them smaller. In other words, in glass etching, since the glass is amorphous, the etching progresses uniformly, and the side etch below the etching mask is thick (this is a measure of the size of the side etch shown in Figure 3). The etch factor d/r becomes extremely small. Also, since the value of the etch factor also varies, it is difficult to ensure dimensional accuracy and it is necessary to design with the amount of variation taken into account, making it difficult to downsize the flat crystal resonator. Note that 6 is an etching mask made of metal such as A11.

The present invention aims to eliminate such drawbacks, and aims to provide a small and thin flat crystal resonator.

The present invention is to use a quartz plate as the material of at least one of the two-stage/t-fenced support case and the lid of the conventional flat type quartz crystal resonator.

FIG. 4 shows a cross-sectional view of a flat crystal resonator using the present invention. Components having the same reference numerals as those in the conventional example will not be described.

7 is a support case made of a crystal plate with two-stage half-etching. 7a and 7b are side wall portions formed by etching. Since a pattern of electrode extensions from a crystal piece is formed on the stepped side wall portion 7b, an appropriate inclination is provided to facilitate pattern formation. On the other hand, the side wall portion 7a on the opposite side is almost upright, and the side wall opposite to the stepped portion of the crystal piece 2 and the support case 7 is designed to prevent the crystal piece 2 from colliding with the support case 7 due to impact or the like. The structure is such that the gap with the portion 7b can be minimized.

By using a quartz plate as the material for the support case, it is possible to perform highly accurate two-stage half-etching with a large etch factor, with little side etching, using anisotropic etching, which is the difference in etching speed due to the crystal axis of the quartz crystal. We were able to make the type crystal unit smaller and thinner.

In addition, since the lid body 5 is made of a flat plate of metal or glass, the lid body 5 can be manufactured by etching, etc., so the surface precision of the sealing surface 5a is improved, the yield of hermetic sealing is improved, and reliability is also increased. .

Further, the respective inclination angles of the side wall portions 7a and 7b are generally different. This is derived from the crystal structure of quartz.

By appropriately selecting the cut-out angle of the crystal plate, the inclination angle of the side wall portion 7a on the opposite side to the stepped side can be set to a substantially right angle, making it easy to form an electrode pattern with the inclination of the side wall portion 7b on the stepped side. It is also possible to do so.

Although only the support case, which is a component of the flat crystal resonator container, has been described above, as in another embodiment of the present invention shown in FIG. You can also do that.

Figure 5 is a cross-sectional view, and in this crystal oscillator, there are many parts where the support case 7 and the lid 8 can be manufactured in a common process (which increases the mass production effect and greatly reduces costs). (You can obtain an inexpensive crystal oscillator.

By implementing the present invention in this way, a thin and small crystal resonator can be obtained at low cost.

The effect was great.

[Brief explanation of drawings]

Figure 1 shows the first conventional example, Figure 2 shows the second conventional example in which the support case is etched in two stages, and both are cross-sectional views of a flat crystal resonator. Figure 3 explains the etching factor. Schematic diagram of sudame. FIG. 4 is a cross-sectional view of a flat type crystal resonator according to one embodiment of the present invention, and FIG. 5 is a cross-sectional view of a flat type crystal resonator according to another example of the present invention. 2...Crystal piece, 5.8...Lid body, 7...Support case, 7a...Side wall portion opposite to stepped side, 7b ...
...Stepped side wall part. Fig. 1 Fig. 2 Fig. 3 Fig. 4' / 10 No. 5
figure

Claims (1)

[Claims] In a container for a flat type crystal oscillator consisting of a support case and a lid for hermetically sealing a crystal piece, at least one of the support case and the lid is half-etched in two stages. A crystal resonator container, wherein at least one of the case and the lid is formed from a crystal plate.