JPH02153611A - Piezo-electric tuning fork vibrator - Google Patents

Abstract

PURPOSE:To improve a characteristic by notching slits in a piezo-electric substrate, to form a tuning fork part, forming an electrode on at least one surface side of the tuning fork part, and respectively specifying the distance from the deepest edge of the slit to the edge of respective electrodes on a slit notching- side and that to the edge of the electrodes on an anti-slit notching mouth-side and the width of respective electrodes. CONSTITUTION:The slit for generating tuning fork part 3 and the slits 4 for detaching tuning fork part are provided for the rectangular piezo-electric sub strate 2. An electrode 6 is installed on the nearby part of the deepest edge 3b in the slit 3, electrodes 7 and 7 along respective side edges 5c and 5c of both arm parts 5 and 5, and electrodes 10, 11 and 11 on the back side of the tuning fork part by facing the electrodes 6, 7 and 7. The distances l1 and l2 from the deepest edge 3b to the edge of the slit notching mouth 3a-side of the electrodes 6, 7 and 7 are set to be more than L/3 and less than 2L/3, the distance l3 to the edge of the electrode 6 on the anti-slit notching mouth-side to be more than L/3 and less than 2L/3. The widths of the electrodes 6, 7 and 7 are set to be less than W/2. Thus, the mountain and valley rate of the imped ance characteristic and a band are enlarged and the characteristic improves.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a piezoelectric tuning fork vibrator, and more particularly to a piezoelectric tuning fork vibrator with an improved electrode pattern.

[Conventional technology]

Fig. 5 [1111, (
This will be explained with reference to bl.

As shown in FIG. 5 011, the piezoelectric tuning fork vibrator 51 is
A square piezoelectric substrate 52 has a slit 53 for forming a tuning fork portion,
A tuning fork part having arm parts 55.55 is formed on both sides of the tuning fork part forming slit 53, and the edges of the tuning fork part forming slit 53 and both arm parts 55.55 are provided. Electrodes 56.57.57 along each side edge of 55
is formed. 58 is an extraction electrode.

Further, as shown in FIG. 5 (011), a common electrode 60 is formed on the back side of the piezoelectric substrate 52 to commonly face the electrodes 56, 57, and 57.

[Problem to be solved by the invention]

The conventional piezoelectric tuning fork vibrator 51 described above does not have sufficiently satisfactory characteristics such as large variations depending on the product, and improvements have been desired.

Therefore, an object of the present invention is to provide a piezoelectric tuning fork vibrator with improved characteristics by improving the electrode pattern.

[Means to solve the problem]

In the piezoelectric tuning fork vibrator of the present invention, a long slit is cut into a piezoelectric substrate to form a tuning fork portion having arm portions each having a width W on both sides of the slit, and at least one side of the tuning fork portion has the deepest end of the slit. Electrodes are formed near the slit and along each side edge of both arms, and the distance MIB, 12, from the deepest end of the slit to the edge of each electrode on the slit incision side is L/3 or more 2L/
3 or less, the distance t from the deepest end of the slit to the edge of the electrode in the vicinity of the deepest end on the side opposite to the slit notch is not less than L/3 and not more than 2L/3, and the width W of each electrode is is W
/2 or less.

〔Example〕

Hereinafter, the present invention will be explained in more detail based on embodiments shown in the drawings. Here, 1st TfIJial is a front view of a piezoelectric tuning fork vibrator according to an embodiment of the present invention, 1) is a back view of the same,
FIG. 2 is a conceptual diagram showing the electrode formation range of the piezoelectric tuning fork vibrator shown in FIG. 1, FIG. 3 is a diagram corresponding to FIG. 2 of another embodiment of the present invention, and FIG. FIG. 3 is an impedance characteristic diagram of a piezoelectric tuning fork vibrator according to an embodiment and a conventional piezoelectric tuning fork vibrator. Note that the present invention is not limited to the following examples.

The piezoelectric tuning fork type vibrator 1 shown in FIG. , an electrode 6 is formed near the deepest end 3 of the tuning fork forming slit 3 (see FIG. 2), and each side end 5C, 5c of both arms 5.5 is
2), and electrodes 10, 1 are formed on the back side of the tuning fork portion, facing the electrodes 6, 7.7.
1114: Provided. 8, 8.8 are extraction electrodes, and 12.12 is a connection electrode.

As shown in detail in FIG. 2, when the length of the tuning fork forming slit 3 is L and the width of the arm 5.5 of the tuning fork is W, the area where the electrodes 6.7.7 are formed is It is stipulated as follows:

That is, the electrode 6 is connected from the deepest end 3 of the tuning fork forming slit 3.
, 7.7 slit notch 3. Distance to side edge 1.
．． 12 is L/3 or more and 2L/3 or more), and the maximum ff of the tuning fork forming slit 3! Distance from 3I to the edge of the electrode 6 on the opposite side of the slit notch! 13 is greater than or equal to L/3 and less than or equal to "i?2L/3" @ jl and 12.t are each independent and do not necessarily need to match.

Further, the width W1 of the portion of the electrode 6 along the tuning fork forming slit 3 and the width W2 of the electrode 7.7 are equal to or less than W/2.

The electrode 10 on the back side is formed in a region facing the electrode 6 on the front side. Further, the electrode 11.11 on the back side is formed in a region opposite to the electrode 7.7 on the front side, in a portion closer to the tip of the tuning fork portion than the edge of the electrode 1O on the side opposite to the slit notch. ing.

FIG. 3 shows a piezoelectric tuning fork vibrator 21 according to another embodiment of the present invention.
This figure shows a tuning fork part, and an electrode 26 is formed near the deepest end 23 of the tuning fork part forming slit 23.
Its shape is rounded. Further, electrodes 27.2 along the side ends 25c, 25c of the arms 25, 25
The edge shape of 7 is also rounded.

In this case as well, the formation area of each electrode 26, 27, 27 is defined in the above-mentioned area. However, the length to the edge l,
,j! 2. l, is the length to the maximum position of the rounded edge, and @W+, Wq is the maximum width.

FIG. 4 shows the measured impedance characteristics of the piezoelectric tuning fork vibrator 1 shown in FIG. 1, which is represented by a solid line. For comparison, the impedance characteristics of the conventional piezoelectric tuning fork vibrator 51 shown in FIG. In this case, the peak-to-valley ratio and band of the impedance characteristics become larger, and the characteristics are improved.

Furthermore, the stability of the characteristics was also good, with little variation.

〔Effect of the invention〕

According to the present invention, a slit of length L is cut into a piezoelectric substrate to form a tuning fork portion having arm portions of width W on both sides of the slit, and at least one side of the tuning fork portion has a portion near the deepest end of the slit. Electrodes are formed along each side edge of both arm parts, and the distance 11.12 from the deepest end of the slit to the edge of each electrode on the slit incision side is not less than L/3 and not more than 2L/3, and the slit Distance from the deepest end to the edge of the electrode near the deepest end on the side opposite to the slit incision! 3 is L/3 or more 2
L/3 or less, and the width W of each electrode is W/2 or less. A piezoelectric tuning fork vibrator is provided, which improves characteristics such as reducing variations among products. can.

[Brief explanation of the drawing]

Impie of a vibrator and a conventional piezoelectric tuning fork vibrator [Explanation of symbols] 1.21 Piezoelectric tuning fork vibrator 2 Piezoelectric ceramic plate 323 Tuning fork portion forming slit 3, . 23. . . . slit notch 31, . 231. ...Deepest end of slit 5.25...
Arm portions 5c, 25c... Side ends of arm portions 6.7.10, 11, 26.27... Electrodes.

Claims (1)

[Claims] 1. A slit of length L is cut in the piezoelectric substrate to form a tuning fork portion having arm portions of width W on both sides of the slit, and at least one side of the tuning fork portion includes a portion near the deepest end of the slit and each side of both arm portions. Electrodes are formed along the edges, and the distance l from the deepest edge of the slit to the edge of each electrode on the slit incision side
_1, l_2 are L/3 or more and 2L/3 or less, and the distance l_3 from the deepest end of the slit to the edge of the electrode near the deepest end on the side opposite to the slit notch is L/3 or more and 2L/3.
A piezoelectric tuning fork vibrator characterized in that the width W of each electrode is equal to or less than W/2.