JP2003115747A - Lame mode crystal oscillator - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a lame mode crystal oscillator small in equivalent series resistor R1 . SOLUTION: This oscillator is equipped with an oscillation part, a connection, and a support. The above oscillation part is connected to the frame of the support via the connection, and the thickness of the above oscillation part is made thinner than the frame. As a result, the lame crystal oscillator small in equivalent series resistor R1 can be materialized.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a Lame mode crystal oscillator having a high frequency. In particular, the present invention relates to a Lame mode crystal oscillator having an oscillator shape and an electrode configuration that are optimal as a reference signal source for portable devices and consumer devices that are highly demanded for high frequency, small size, high accuracy, impact resistance, low cost, etc. .

[0002]

2. Description of the Related Art As a conventional technique, a Lame mode crystal oscillator using crystal is well known. FIG. 2 shows a top view (a) and a side view (b) of this conventional Lame mode crystal resonator. In FIG. 2, the Lame mode crystal oscillator 15 is configured to include a vibrating portion 16, connecting portions 17 and 18, and a supporting portion 22. Further, the support portion 22 is the frame 1
It is configured by including 9, 20 and a mount portion 21. Further, the vibrating portion 16 is connected to the frames 19 and 20 via the connecting portions 17 and 18, respectively, and the frames 19 and 20 are connected to the mount portion 21. The vibrating portion, the connecting portion, the frame and the mount portion are integrally formed by a chemical etching method. Further, the fundamental wave vibration of the Lame mode can be strongly excited when the width W and the length L are equal, that is, when L = W and the signs of the piezoelectric constants in the width W and the length L directions are different. In detail, for example, 2 in FIG.
As shown by the dotted broken line, when the displacement of extension in the L direction is
A contraction displacement occurs in the direction. By applying an alternating voltage, the displacement in the vibration direction can be reversed.

[0003]

In the conventional Lame mode crystal resonator, the crystal resonator has a constant thickness T. In this case, the larger the area of the vibrating part (lower frequency), the smaller the equivalent series resistance R ₁ , and the quality factor. The Q value increases. However, the Lame mode crystal oscillator has a frequency of width W or length L.
Since it is inversely proportional to, the area of the vibrating part becomes smaller when trying to increase the frequency. At the same time, the thickness T relative to the length L and the width W becomes relatively thick. Therefore, the electromechanical conversion efficiency is reduced, and as a result, the equivalent series resistance R ₁ is increased, and the quality factor Q value is reduced. Therefore, at high frequency, the equivalent series resistance R
There has been a demand for a microminiature Lame mode crystal oscillator having an oscillator shape and an electrode configuration in which ₁ is small and the quality factor Q value is high.

[0004]

SUMMARY OF THE INVENTION It is an object of the present invention to provide a Lame mode quartz crystal resonator that advantageously solves the conventional problems by the following method.

That is, the first mode of the Lame mode crystal oscillator of the present invention is a Lame mode crystal oscillator comprising a vibrating section, a connecting section and a supporting section, wherein the vibrating section is connected via the connecting section. Is connected to the frame of the supporting portion, and the thickness of the vibrating portion is thinner than the thickness of the frame.

A second aspect of the Lame mode crystal oscillator of the present invention is the Lame mode crystal oscillator according to the first aspect, wherein the thickness of the connecting portion is smaller than the thickness of the frame.

According to a third aspect of the Lame mode crystal oscillator of the present invention, the Y plate has an angle θ of about 34 ° to 3 ° around the electric axis x axis.
The Lame mode according to the first aspect, wherein the oscillator is formed from a quartz plate that is rotated by 8 ° and further rotated by an angle φ = ± 45 ° ± 5 ° around a new axis y ′ axis of the mechanical axis y axis. It is a crystal unit.

[0008]

As described above, the Lame mode crystal oscillator of the present invention is formed so that the thickness of the vibrating portion thereof is thinner than the frame of the supporting portion, so that the electric field strength of the vibrating portion is increased. That is, since the electromechanical conversion efficiency is improved, it is possible to realize an ultra-small Lame-mode crystal oscillator having excellent electrical characteristics and a high frequency.

[0009]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be specifically described below with reference to the drawings.

(Embodiment) FIG. 1 is a top view (a) and a side view (b) of a Lame mode crystal resonator 1 according to an embodiment of the present invention. The Lame mode crystal oscillator 1 is configured to include a vibrating portion 2, connecting portions 4 and 5, frames 6 and 7, and a supporting portion 13 including a mount portion 8. That is, the vibrating portion 2 is connected to the frames 6 and 7 through the connecting portions 4 and 5, respectively, and further,
The frames 6 and 7 are connected to the mount portion 8.

Further, the thickness T ₀ of the vibrating portion 2 is formed to be thinner than the thickness T ₁ of the frames 6 and 7 of the support portion 13 and the mount portion 8. In this embodiment, the thickness is reduced from one surface of the vibrating portion 2, but it may be reduced from both surfaces. Further, in this embodiment, the thickness of the connecting portions 4 and 5 is formed to be smaller than the thickness of the frames 6 and 7 and the mount portion 8, but the thickness of the connecting portions 4 and 5 is equal to that of the frames 6 and 7.
The thickness of 7 and the mount portion 8 may be the same. Further, the processing of the vibrator shape and the control of the thickness are performed by a chemical etching method.

Further, an electrode 3 and an electrode 11 which are opposed to each other with different polarities are arranged on the upper surface and the lower surface of the vibrating portion 2. The electrode 3 is arranged so as to extend to the mount portion 8 via the one connection portion 4 and the frame 6, and the mount portion 8 is provided with an electrode 9 serving as one electrode terminal. The electrode 11 is connected to the other connecting portion 5
An electrode 14 is formed on the mount portion 8 so as to extend to the mount portion 8 via the frame 7 and serve as the other electrode terminal. That is, a two-electrode terminal is formed. Furthermore,
In this embodiment, in order to improve the workability of supporting and fixing with a lead wire or the like, the electrode 14 is connected to the electrode 10 arranged on the upper surface of the mount portion 8 through the electrode 12 arranged on the side surface of the mount portion 8. Has been done. That is, the electrode 9 and the electrode 10 are arranged on the same plane of the mount portion 8. In this embodiment, only the electrodes of the vibrating section are arranged so as to oppose each other. However, the electrodes in other portions may be arranged to face each other, and the influence on the equivalent series resistance R ₁ is negligibly small.

The vibrating portion 2 has a width W ₀ , a length L ₀ and a thickness T.
_It has a dimension of ₀ (the thickness of the frame and the mount portion is T ₁ ). In this embodiment, the Lame mode crystal resonator having a shape in which the width W ₀ and the length L ₀ are equal to each other has been described. That is, the vibrator vibrates in the fundamental wave mode. However, the present invention is not limited to the above-mentioned oscillator, and for example, the present invention includes an overtone Lame mode crystal oscillator. More specifically, the electrodes that oppose each other in the thickness direction of the vibrating portion are arranged so as to have different polarities, and the adjacent electrodes are also arranged so as to have different polarities.
By thus configuring the electrodes of the vibrating portion, an overtone Lame mode crystal oscillator can be obtained. As an example, by further connecting two vibrating portion having dimensions of width W _{0 =} length L ₀ in the length L ₀ direction, the electrode of the vibrating portion is divided into three parts, the third overtone Lame mode A crystal unit can be realized. That is, n
By connecting the individual pieces, a (n + 1) th-order overtone Lame mode crystal resonator can be obtained.

Further, in the Lame mode crystal resonator of the present invention, the four corners are the nodes regardless of the fundamental wave and overtone modes. Therefore, the present invention also includes a shape in which the connecting portions are provided at the four corners and the vibrating portion and the frame are connected via the connecting portions. As an example, two connecting parts are connected to the frame, and the remaining two connecting parts are connected to the frame or the mount part.

Next, the cut angle of the Lame mode crystal oscillator of the present invention will be described. Now, assuming that the electric axis x axis, the mechanical axis y axis, and the optical axis z axis, which are crystal axes of quartz, rotate a plate perpendicular to the y axis and a Y plate around the x axis by an angle θ = 34 ° to 38 °. , Furthermore, the angle φ = ± 45 ° around the new y-axis of the y-axis
The vibrator of the present invention is formed from a quartz plate rotated by ± 5 ° (± (40 ° to 50 °)). In other words, the angle θ =
The crystal plate rotated by 34 ° to 38 ° is further ± (40 °
˜50 °) is rotated to form a Lame mode crystal oscillator. Since the oscillator formed from such a cut angle has a primary temperature coefficient α of zero at any temperature including room temperature, a Lame mode crystal oscillator having a small frequency change with respect to temperature can be realized. That is, a Lame mode crystal oscillator having excellent frequency-temperature characteristics can be obtained.

By forming the vibrator in this way,
Since the electric field applied in the thickness direction of the vibrating portion is large and the electromechanical conversion efficiency is improved, it is possible to realize a Lame mode crystal resonator having a small equivalent series resistance R ₁ and a high quality factor Q value. Further, since the frame and the mount portion having the outer shape can be thickened, the strength of the vibrator can be further increased. As a result, since one end of the vibrator can be fixed to the pedestal or the lead wire with an adhesive or solder, workability in mass production is excellent and the number of steps can be reduced. That is, an inexpensive Lame mode crystal oscillator can be realized. At the same time, a Lame mode crystal unit that is strong against impact can be obtained. Further, since the thickness dimension with respect to the contour dimension (width W ₀ , length L ₀ ) is extremely small, it is possible to realize an ultra-small Lame mode crystal oscillator having a high R value, a small R ₁ and a high frequency.

[0017]

As described above, by providing the Lame mode crystal oscillator having the oscillator shape, the electrode structure and the cut angle according to the present invention, the following remarkable effects can be obtained. (1) The thickness dimension of the vibrating portion can be made extremely small relative to the width and length dimensions of the vibrating portion. Therefore, the electric field strength of the vibrating portion that drives the Lame mode crystal oscillator becomes extremely large, and the electromechanical conversion efficiency is significantly improved. As a result, the equivalent series resistance R ₁ is small, the quality factor Q value is high,
Moreover, it is possible to obtain an ultra-small Lame mode crystal oscillator. (2) Since the outline dimension of the vibrating portion can be reduced, a high-frequency Lame mode crystal oscillator can be realized. (3) By arranging electrodes having different polarities on the opposing surface of the vibrating portion, the electric field acts perpendicularly to the electrodes. As a result, the electromechanical conversion efficiency is improved, so that a Lame mode crystal resonator having a small R ₁ and a high Q value can be realized. (4) Since the vibrator including the vibrating portion, the connecting portion, and the supporting portion is integrally formed by the chemical etching method, workability in mass production is excellent and the number of steps can be reduced. That is, an inexpensive Lame mode crystal oscillator can be provided. (5) Since the first-order temperature coefficient α of the oscillator becomes zero, it is possible to realize a high-precision Lame mode crystal oscillator having excellent frequency-temperature characteristics. (6) Since the outer frame and the mount portion can be made thicker, a Lame mode crystal oscillator that is strong against impact can be obtained.

[Brief description of drawings]

FIG. 1 is a top view (a) and a side view (b) of a Lame mode crystal resonator according to an embodiment of the present invention.

FIG. 2 is a top view (a) and a side view (b) of a conventional Lame mode crystal oscillator.

[Explanation of symbols]

W, W ₀ width of the vibrating part L, length of the L ₀ vibrating part T, T ₀ thickness of the vibrating part T ₁ frame, mount part thickness 1,15 Lame mode crystal resonator 2,16 vibrating part 3,9, 10, 11, 12 Electrodes 4, 5, 17, 18 Connection part 13, 22 Support part 8, 21 Mount part 6, 7, 19, 20 Frame

Claims (3)

[Claims] 1. A Lame mode quartz crystal resonator comprising a vibrating section, a connecting section and a supporting section, wherein the vibrating section is connected to the frame of the supporting section through the connecting section, A Lame mode crystal unit having a thickness smaller than that of the frame. 2. The Lame mode quartz crystal resonator according to claim 1, wherein the thickness of the connecting portion is smaller than the thickness of the frame. 3. The Y plate has an angle θ = 34 about the electric axis x axis.
The oscillator is formed of a quartz plate which is rotated by 38 ° to 38 ° and further rotated by an angle φ = ± 45 ° ± 5 ° around a new axis y ′ axis of the mechanical axis y axis. The Lame mode crystal oscillator according to Item 1.