JPS622828Y2 - - Google Patents

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a crystal resonator in which a heating electrode is arranged on a crystal plate of an AT cut to compensate for temperature.

[Prior art]

As a technique of this kind, a technique in which a heating electrode is disposed on a quartz plate is already known in Japanese Utility Model Publication No. 38-909. As shown in FIG. 1, this is a crystal resonator in which heating electrodes are arranged almost uniformly around a crystal plate. Excitation electrodes B and B' are arranged in the center of the crystal plate A, and heating electrodes C and B' are arranged around the edge of the crystal plate.
C′ are uniformly arranged.

This crystal resonator attempts to stabilize the frequency-temperature characteristics by controlling the temperature using the heating electrode as a heat source or by using another control element. However, in reality, the crystal plate causes internal distortion due to thermal stress caused by the heat generated from the heating electrode, which causes fluctuations in the resonant frequency of the crystal resonator. With heating electrodes, it is difficult to compensate for this variation.

[Structure of the present invention]

Therefore, in order to compensate for frequency fluctuations caused by thermal stress, we found out what kind of relationship the heating produces with respect to the axial direction. For example, in an AT cut, it is possible to rotate the When stress is applied to a crystal plate parallel to the plane formed by the X and Z' axes of the crystal coordinate axes (X, Y', Z') after rotating 35°18' clockwise as an axis, the frequency changes. The rate characteristic has a negative frequency change in the region of 0≦θ≦30° with ±30° as the center around the Z′ axis, and 30°≦θ.
It was found that positive frequency changes were obtained in the region of ≦90°.

FIG. 2a is a graph showing the frequency change rate on the vertical axis and the frequency change rate due to stress at each angle of ±90° with the Z' axis being 0° on the horizontal axis. Figure 2b is
It is a front view explaining the axial direction of the crystal plate, and the horizontal axis is
Z' axis, vertical axis is X axis, ±30 around Z' axis
° is a thermal central axis, and the heating electrodes may be arranged thermally symmetrically with respect to this central axis. At this time, the ratio △f/f between the frequency f when no stress is applied and the frequency difference △f before and after stress is applied is approximately ±30 from the Z' axis.
The rate of frequency change reverses between positive and negative at the border of ゜. In this invention, we focused on the fact that this frequency change due to stress is also added as thermal stress when heat is applied, and we have found a crystal oscillator that stabilizes the frequency by balancing the thermal stress. It is. Note that the heating electrodes do not necessarily have to be arranged mechanically symmetrically with respect to the thermal central axis.

By arranging the heating electrodes thermally symmetrically about ±30° from the Z' axis in this way, the influence of internal thermal stress distortion can be removed, and the heating electrodes can be uniformly arranged as shown in Figure 1. Frequency stability that cannot be achieved with a configuration in which

[Purpose of this invention]

The purpose of this invention is to eliminate the influence of internal distortion due to thermal stress while taking into account the central symmetry of the thermal stress effect, and to achieve crystal oscillation that virtually completely eliminates the influence of thermal stress on the frequency of the crystal oscillator. It is about providing children.

[Examples and Effects of the Invention]

FIG. 4 is a front view of a crystal resonator which is an embodiment of the present invention.

At the center of both sides of the crystal plate 1 are excitation electrodes 2, 2'.
are arranged, and terminal electrodes 3, 3' are arranged from there to the periphery.
has been extended. Both of these excitation electrodes 2, 2' and terminal electrodes 3, 3' are installed by vacuum-depositing a highly conductive metal such as gold or silver.

The heating electrodes 9, 10, 11, and 12 are installed by vacuum-depositing a high-resistance metal such as a nickel-chromium alloy. It lies between the angle θ ₁ = 10° and the angle θ ₂ = 60° with the Z' axis passing through the center of the excitation electrode 2 and the strip formed by the concentric circles as the starting line, which is 10 in Fig. 2a. In order to exactly cancel out the negative frequency change rate between 30° and 30° and the positive frequency change rate between 30° and 60°, the heating electrodes 9 and 1 are placed in this area.
0, 11, and 12 are provided, and are located in the fourth quadrant, the fourth quadrant, the fourth quadrant, and the fourth quadrant, respectively, which are formed when the crystal plate is divided into four by the X axis and the Z' axis. Note that the signs of the angles θ ₁ and θ ₂ are positive and negative, respectively, when the starting line Z' axis is rotated counterclockwise and clockwise toward the excitation electrode 2.

The connection electrode 13 connects the excitation electrode 2 and the heating electrodes 9 and 1.
Similarly, the connection electrode 14 is located between the excitation electrode 2 and the heating electrodes 10 and 11 and is located between the first and second quadrants. and connection electrode 1
5 is similarly located between the excitation electrode 2 and the heating electrodes 9 and 12, spanning the first and second quadrants, respectively, and is arranged mutually with the heating electrode, and each connecting electrode connects the ends of the heating electrode to each other. Connected. Connecting electrodes 16 and 17 used as terminals are connected to the ends of the heating electrodes 11 and 12.

These connection electrodes 13, 14, and 15 are placed between the heating electrodes 9, 10, 11, and 12 and the excitation electrode 2, with a distance maintained so as not to contact each other, and are made of the same quality as the excitation electrode 2. Manufactured by vacuum deposition of conductive metal. Note that connection electrodes 16 and 17 used as terminals are also deposited in the same manner.

In the crystal resonator constructed in this manner, the heat distribution of the crystal plate 1 is centrally symmetrical at an angle of about ±30° from the Z' axis due to the heat generated in the heating electrodes 9, 10, 11, and 12. Since it is possible to eliminate the influence of internal distortion caused by thermal stress.

FIG. 5 shows another embodiment in which only the heating electrode 9 of the previous example is used as the heating electrode, and connection electrodes 18 and 19 are arranged almost as far around the entire circumference of the crystal plate 1 as possible. be.

Note that this heating electrode may be replaced with the heating electrodes 10, 11, or 12 shown in the previous example.

FIG. 6 shows yet another embodiment, using the heating electrodes 9 and 11 in the embodiment of FIG.
Further, interconnection is performed by the connection electrode 20, and terminal extraction is performed by the connection electrodes 21 and 22.

As described above, by arranging the thermal stress generated in the heating electrode part of the crystal plate symmetrically with respect to the thermal center axis of the heating electrode, the influence of thermal stress is removed and a stable crystal resonator is realized. .

In the above embodiments, the lower limit of the angle θ ₁ and the upper limit of the angle θ ₂ specifying the angular region of the heating electrode can be determined by adjusting the angular region and area of the connecting electrode as appropriate, according to experiments, |θ ₁ |min =5° and |θ ₂ |max=90°, and it was confirmed through experiments that the range of θ ₁ =10° and θ ₂ =60° is a good angular range.

FIG. 3 is an example of a temperature compensation control circuit diagram of a crystal resonator according to the present invention, in which a heater H constituted by a heating electrode and a positive temperature sensitive resistance element Th (a temperature sensitive element whose resistance value increases as the temperature rises) are shown. This is a series circuit with a resistor element, etc.). Here, the temperature sensing element Th
may be attached to the outer wall of the container that seals the crystal resonator, or may be mounted on the printed circuit board of the oscillation circuit OSC.

Even with such a temperature control circuit, the crystal resonator according to the present invention can obtain a frequency change rate within ±1×10 ⁻⁶ with respect to temperature changes from −10° C. to +50° C. That is, from the relationship between the angle θ measured with the Z' axis as the starting line on the X-Z' plane in Figure 2a and the frequency change rate, by setting the heating electrode with the axis of symmetry around ±30 degrees, By eliminating the influence of thermal stress and canceling out frequency changes, we were able to perform frequency temperature compensation stably.

[Brief explanation of the drawing]

Figure 1 is a front view of a conventional crystal resonator;
Figure a is a frequency change rate characteristic curve diagram due to stress at each angle of the crystal plate, Figure 2 b is a front view explaining the axial direction of the crystal plate, and Figure 3 is temperature control used in the crystal resonator according to the present invention. The circuit diagrams, FIGS. 4, 5 and 6 are front views of a crystal resonator which is an embodiment of the crystal resonator of the present invention. 1... Crystal plate, 2, 2'... Excitation electrode, 9, 1
0,11,12...Heating electrode, 13,14,1
5, 18, 19, 20, 21, 22... connection electrode.

Claims (1)

[Scope of Claim for Utility Model Registration] In a crystal resonator in which an excitation electrode is provided on a crystal plate of an AT cut, a connection electrode on the outer periphery of the excitation electrode, and a heating electrode located on the periphery of the connection electrode, ( ) at least one heating electrode made of a high-resistance metal along the edge of the quartz plate, the at least one heating electrode comprising a high-resistance metal having ± With an angle of 30° as the central axis of the thermal stress, a region where the frequency change changes positively and a region where the frequency changes negatively from the central axis of the thermal stress are thermally symmetrical and pass through the center of the excitation electrode. (b) At least two connecting electrodes made of a highly conductive metal are arranged in an angular range of ± (10° to 60°) measured from the Z' axis as the starting line, and are connected to the excitation electrode. between the heating electrode,
A crystal resonator characterized in that the heating electrode and the connecting electrode are electrically connected in series with a distance maintained so as not to contact each other.