JP2004096568A - It-cut quartz crystal resonator - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an IT-cut quartz crystal resonator capable of obtaining excellent vibration characteristics by defining a holding position. <P>SOLUTION: A surface crossing an Y-axis of a crystal of quartz crystal at right angles is rotated at about 34° around an X-axis, the surface is rotated at about 19° around a Z-axis from the above rotated position, a round or rectangular quartz crystal piece is cut out from the rotated surface, and an electrode is formed on both front and rear surfaces of the quartz crystal piece. The product obtained by this method holds at least a pair of opposing edge portions of portions of 18°±18° and 198°±18° and portions of 108°±18° and 288°±18° from the Z'-axis of the plate surface of the quartz crystal piece. <P>COPYRIGHT: (C)2004,JPO

Description

[0001]
BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an IT-cut quartz resonator, and more particularly to a holding position at which good vibration characteristics can be obtained.
[0002]
[Prior art]
(Background of the Invention) As a conventional twice-rotating quartz oscillator, for example, an SC-cut quartz oscillator disclosed in JP-A-11-177376 is known.
In this SC-cut quartz resonator, for example, as shown in FIG. 4, a plane orthogonal to the Y axis of the quartz crystal is rotated by about 33 ° about the X axis, and from this rotated position, about the Z axis. An electrode is formed on a crystal blank 1 cut out from a plane rotated by about 22 °.
[0003]
This SC-cut crystal resonator has a cubic curve-like temperature characteristic similar to that of the AT cut, and its inflection point is 94 ° C., and is used as a crystal resonator of a so-called constant-temperature-bath type crystal oscillator. .
[0004]
However, since the temperature of the inflection point is 94 ° C. in the SC-cut crystal resonator, if an extreme value lower than this is set as the target temperature of the thermostat, the target temperature will be 65 ° C. to 85 ° C.
For this reason, in the case of an oscillator having a wide operating temperature range, for example, when it is required to use the high-temperature side up to 80 ° C., the margin with respect to the set temperature of the thermostatic chamber is reduced.
For this reason, it becomes difficult to control the temperature of the thermostat at a constant temperature, and it becomes impossible to maintain a constant oscillation frequency.
[0005]
Therefore, it has been considered to use an IT-cut quartz resonator.
The IT-cut crystal resonator is a twice-rotating crystal resonator similar to the SC-cut crystal resonator.
In the IT cut crystal resonator, for example, as shown in FIG. 5, a plane orthogonal to the Y axis of the crystal is rotated about 34 ° about the X axis, and further from this rotated position about the Z axis. An electrode is formed on a crystal blank 2 cut out from a plane rotated by about 19 °.
[0006]
The temperature characteristics of this IT-cut quartz resonator are also substantially the same as those of the SC-cut quartz resonator, and the inflection point temperature is as low as 74 ° C.
Therefore, the extreme value on the higher temperature side than the inflection point is 85 ° C. to 105 ° C.
Therefore, even when the highest temperature in the operating temperature range is required to be 80 ° C., the set temperature of the constant temperature bath can be set in the range of 85 ° C. to 105 ° C., and the temperature control can be performed relatively easily. .
[0007]
However, there are few practical examples of IT-cut quartz resonators, and the relationship between the supporting position and the vibration characteristics has not been clarified at all.
[0008]
[Problems to be solved by the invention]
The present invention has been made in view of the above circumstances, and it is an object of the present invention to provide an IT-cut crystal resonator that can obtain good vibration characteristics by defining a supporting position.
[0009]
[Means for Solving the Problems]
According to the first aspect of the present invention, a plane orthogonal to the Y axis of the quartz crystal is rotated by about 34 ° about the X axis, and cut out from a plane rotated by about 19 ° about the Z axis from the rotated position. In the case where the electrodes are formed on the quartz piece, the 18 片 ± 18 ゜ and 198 ゜ ± 18 ゜ parts and the 108 ゜ ± 18 ゜ and 288 ゜ ± 18 ゜ parts are mutually An IT-cut crystal unit characterized by holding at least one pair of opposing edge portions.
[0010]
According to a second aspect of the present invention, in the first aspect, the crystal element is an IT-cut crystal element characterized in that the crystal element is a round plate, and in the third aspect, the crystal element is a rectangular element. A fourth aspect of the present invention is an IT-cut crystal resonator, wherein one of the diagonal lines connecting the corners of the crystal element is within 18 ° ± 18 ° from the Z ′ axis, and the other is the other. This is an IT-cut crystal resonator characterized by being within a range of 108 ° ± 18 ° from the Z ′ axis.
[0011]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, an embodiment of the present invention will be described in detail with reference to the drawings.
FIG. 1 is a plan view of a round plate-shaped IT-cut crystal blank 3.
Such an IT-cut crystal blank rotated a plane orthogonal to the Y-axis of the crystal of the crystal about 34 ° about the X-axis, and further rotated about 19 ° about the Z-axis from this rotated position. It is cut out from the surface.
[0012]
In FIG. 1, the horizontal direction is the Z ′ axis, and the vertical direction is the X ′ axis.
Then, 18 ° ± 18 ° (illustrated A) and 198 ° ± 18 ° (illustrated B), and 108 ° ± 18 (illustrated C) and 288 ° ± 18 ° (illustrated A) from the Z ′ axis of the plate surface of the crystal blank. At least one pair of opposing edges of the part shown in D) is held.
[0013]
The reason for defining the holding position of the crystal blank 1 in this way is as follows.
That is, when the displacement distribution of the plate surface when the piezoelectric vibration was excited on the IT-cut quartz piece was measured, it was observed as shown in FIG.
Generally, in a crystal resonator, it is desirable to hold a portion with little displacement in order to minimize the influence on the vibration characteristics.
[0014]
In FIG. 2, the horizontal direction is the Z ′ axis, and the vertical direction is the X ′ axis.
The position and magnitude of the displacement are represented by contour lines.
Accordingly, the relatively large displacement is located on a line connecting the directions of 160 ° and 340 ° from the Z ′ axis.
Therefore, avoiding this direction, a portion of 108 ° ± 18 ° (shown in A), preferably 18 ° ± 9 ° and 198 ° ± 18 ° (shown in B), and more preferably 198 ° ± 9 ° from the Z ′ axis and 108 Retain at least one pair of opposing edges of a portion of {± 18} (shown C), preferably 108 ± 9 ° and 288 ± 18 ° (shown D), more preferably 288 ± 9 °. To do.
[0015]
In this way, a portion having a relatively small vibration displacement can be held, whereby good vibration characteristics can be obtained.
In addition, the influence of the stress from the holding structure on the vibration characteristics can be reduced, and the stability can be improved.
[0016]
In addition, since such a crystal oscillator is used in a thermostat heated to about 100 ° C., use of a conductive adhesive is avoided, and a holding and excitation electrode is led out using, for example, an alloy of gold-germanium. Electrical continuity may be performed.
In some cases, four points are held to maintain mechanical strength.
In such a case, by holding the four points A, B, C, and D described above, the holding positions can be arranged at equal intervals, which is convenient, and a mechanical balance can be realized.
[0017]
In the embodiment shown in FIG. 1, a description has been given of a case using a crystal plate 3 of a round plate. However, the present invention is not limited to such a case. For example, as shown in FIG. Is also applicable.
In this case, the diagonal line of the crystal blank is 18 ° ± 18 ° (shown in A), preferably 18 ° ± 9 ° and 198 ° ± 18 ° (shown in B), and more preferably 198 ° ± 9 ° from the Z ′ axis. And at least two points facing each other so as to be located at 108 ° ± 18 ° (shown C), preferably 108 ° ± 9 ° and 288 ° ± 18 ° (shown D), more preferably 288 ° ± 9 °. What is necessary is just to hold a corner.
[0018]
【The invention's effect】
As described in detail above, the present invention holds a portion with as little vibration displacement as possible, without impairing the vibration characteristics, and reducing the influence of the holding system on the vibration characteristics. It is possible to provide an IT-cut crystal resonator that can obtain various vibration characteristics.
[Brief description of the drawings]
FIG. 1 is a plan view of a crystal blank according to an embodiment of the present invention.
FIG. 2 is a diagram illustrating a distribution of vibration displacement of an IT-cut quartz piece.
FIG. 3 is a plan view of a crystal blank according to another embodiment of the present invention.
FIG. 4 is a view for explaining a cutting angle of a crystal piece in an SC cut.
FIG. 5 is a diagram for explaining a cutting angle of a crystal piece in an IT cut.
[Explanation of symbols]
1, 2, 3, 4 crystal pieces

Claims (4)

An electrode was formed on a piece of crystal cut out from a plane rotated about 34 ° about the X-axis from a plane orthogonal to the Y-axis of the crystal of the crystal and rotated about 19 ° about the Z-axis from this rotated position. At least one pair of opposing edges of 18 ° ± 18 ° and 198 ° ± 18 ° and 108 ° ± 18 ° and 288 ° ± 18 ° from the Z ′ axis of the plate surface of the crystal blank. An IT-cut crystal unit characterized by holding parts. 2. The crystal resonator according to claim 1, wherein the crystal piece is a round plate. 2. The crystal resonator according to claim 1, wherein the crystal piece is a rectangular plate. 4. The IT according to claim 3, wherein one of the diagonal lines connecting the corners of the crystal blank is in a range of 18 ° ± 18 ° from the Z ′ axis, and the other is in a range of 108 ° ± 18 ° from the Z ′ axis. Cut crystal oscillator.

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