Quartz tuning fork

Abstract

The utility model provides a quartz tuning fork which comprises a base body and two vibrating arms extending outwards from one end of the base body, the upper surface and the lower surface of each vibrating arm are both corroded to form a first groove, and the width of each first groove is gradually increased in the direction close to the base body. According to the scheme, the folding notches are formed in the upper surface and the lower surface of the vibrating arm, so that the electric field force efficiency of the vibrating arm can be improved, and the resistance is reduced; meanwhile, the widths of the first grooves are gradually increased along the direction close to the substrate, so that the closer the first grooves are to the roots of the vibrating arms where the first grooves are located, the smaller the influence of the dependence of crystal axes on the etching speed of the two sides of the first grooves is, and the distance between the two first grooves located on the upper and lower surfaces of the vibrating arms is gradually increased. Therefore, the rigidity of the vibrating arm in the direction close to the base body is gradually increased, and twisting of the vibrating arm can be prevented from occurring from the root of the vibrating arm.

Description

TECHNICAL FIELD

[0001] The utility model relates to a tuning fork technical field especially relates to a quartz tuning fork. BACKGROUND

[0002] In the tuning fork type quartz crystal resonator, a known quartz tuning fork structure usually has a fixed part and a vibrating part extending outward from one end of the fixed part, the vibrating part includes two vibrating arms, the vibrating arms are symmetrical relative to the central axis of the quartz tuning fork wafer, and the width and length of the two vibrating arms are equal. For example, the patent with the publication number CN117579013A discloses a quartz tuning fork structure and a manufacturing method thereof, the quartz tuning fork structure includes a pair of quartz prongs (i.e., vibrating arms), a pair of hammer heads, and a quartz base; a group of V-shaped variable cross-section grooves are arranged on the upper surface and the lower surface of the quartz prongs, and the central axis of the grooves coincides with the central axis of the prongs.

[0003] However, due to the anisotropy of quartz material, in most cases, the cross-sectional shape of the groove formed on the quartz prong by etching is asymmetric with the center line of the groove or the quartz prong depending on the crystal orientation, especially since the etching rate of quartz has crystal axis dependence, in actual production, the smaller the width of the groove to be etched, the more easily the +x-axis direction of the width direction of the quartz prong is etched, which reduces the thickness of the connecting part between the grooves on the upper and lower surfaces of the quartz prong, and causes poor rigidity of the quartz prong.

[0004] During the drop test of the quartz tuning fork, small-size tuning forks are prone to twisting due to the poor rigidity of the quartz prong, which causes the metal sputtered after rough adjustment of the surface of the weighted area (or hammer part) at the top end of the quartz prong to fall off. During normal vibration of the tuning fork, the poor rigidity of the quartz prong causes the body of the quartz prong to twist, the z-direction energy transmitted to the mounting arm is too large, which causes the deformation of the adhesive silver glue, and causes frequency abnormalities. UTILITY MODEL CONTENTS

[0005] Based on the problems existing in the prior art, the utility model aims to solve the technical problem that the quartz tuning fork structure in the prior art causes poor rigidity of the vibrating arm when etching a groove on the vibrating arm due to the crystal axis dependence of the etching rate of quartz.

[0006] The utility model provides a quartz tuning fork, it includes the base body and two vibrating arms that extend outward from one end of the base body, the upper surface and the lower surface of vibrating arm all etch and form first groove, the width of first groove gradually increases along the direction close to the base body.

[0007] According to an embodiment of the utility model, the opening shape of the first groove is isosceles trapezoidal.

[0008] According to an embodiment of the present application, the width difference between the small end and the large end of the first groove is 2-20um.

[0009] According to an embodiment of the present application, the shape of the vibration arm is isosceles trapezoid, and the central axis of the vibration arm coincides with the central axis of the corresponding first groove.

[0010] According to an embodiment of the present application, the width of one end of the vibration arm close to the base is 80-125um, and the width of the other end is 70-120um.

[0011] According to an embodiment of the present application, the upper surface and the lower surface of one end of the vibration arm close to the base are further etched to form a second groove in communication with the corresponding first groove, and the width of the second groove gradually decreases in the direction away from the corresponding first groove.

[0012] According to an embodiment of the present application, the quartz tuning fork further comprises a folding arm, and the folding arm is fixedly connected to one end of the base away from the vibration arm.

[0013] According to an embodiment of the present application, one end of the folding arm away from the base has at least one folding notch.

[0014] According to an embodiment of the present application, the depth of the folding notch in the thickness direction of the folding arm is less than the thickness of the folding arm.

[0015] According to an embodiment of the present application, the folding notches are a pair and are spaced apart on the upper surface of the folding arm.

[0016] The present application has the following beneficial effects:

[0017] The quartz tuning fork provided by the present application has the following advantages: the width of the first groove etched on the vibration arm gradually increases in the direction close to the base, so that the distance between the two first grooves on the upper surface and the lower surface of the vibration arm gradually increases in the direction close to the base, thereby gradually increasing the rigidity of the vibration arm in the direction close to the base, and thus preventing the vibration arm from being twisted at the root. BRIEF DESCRIPTION OF DRAWINGS

[0018] In order to more clearly illustrate the technical solutions in the embodiments or the prior art, the following will briefly introduce the drawings needed to be used in the embodiments or the prior art description. Obviously, the drawings in the following description are only some embodiments of the present application, and for those skilled in the art, other drawings can also be obtained without creative labor.

[0019] Figure 1 is a front structure schematic view of a quartz tuning fork provided by the present application.

[0020] Figure 2 is a back structure schematic view of a quartz tuning fork provided by an embodiment of the present application;

[0021] Figure 3 is a state schematic view of a quartz tuning fork connected with a wafer piece through a folding arm in an embodiment of the present application;

[0022] Reference signs: 1 - base body; 11 - connecting part; 12 - fixing part; 10 - waist groove; 101 - curved surface; 2 - vibrating arm; 20 - first groove; 21 - second groove; 3 - folding arm; 30 - folding notch. DETAILED DESCRIPTION

[0023] The following description of the embodiments is made with reference to the accompanying drawings, which are used to illustrate specific embodiments of the present application that can be implemented.

[0024] The present application provides a quartz tuning fork, which has a structure as shown in Figure 1 and Figure 2 , comprising a base body 1 and two vibrating arms 2 extending outward from one end of the base body 1, the upper surface and the lower surface of the vibrating arm 2 are both etched to form a first groove 20, so as to improve the electric field force efficiency of the vibrating arm 2, reduce the resistance, and the width of the first groove 20 gradually increases along the direction close to the base body 1.

[0025] The influence mechanism and application research of additives on the etching characteristics of quartz single crystal (Zhang Zhaoyun, China Academy of Engineering Physics, 2018) discusses the changes of the etching morphology of quartz with the etching direction, opening size, etching depth and other related factors on pages 36-44, especially Figure 2 .24 directly shows the changes of the lateral etching morphology with the opening size and etching depth, specifically, when the opening is 50um, the etched groove is basically symmetrical relative to the central axis, when the opening is 100um, the “sharp corner” at the bottom of the etched groove has disappeared, it can be determined that the etching speed on both sides of the groove is basically consistent, thereby eliminating the influence of crystal axis dependence on the etching speed on both sides of the groove.

[0026] In the present scheme, since the width of the first groove 20 gradually increases along the direction close to the base body 1, the closer the first groove 20 is to the root of the vibrating arm 2, the greater the width of the first groove 20, and the smaller the influence of the crystal axis dependence on the etching speed on both sides of the first groove 20, thereby making the distance between the two first grooves 20 located on the upper and lower surfaces of the vibrating arm 2 gradually increase, and further determining that the rigidity of the vibrating arm 2 gradually increases along the direction close to the base body 1, which can prevent the vibrating arm 2 from twisting from the root of the vibrating arm 2, and is conducive to promoting the miniaturization design of the quartz tuning fork.

[0027] Further, the opening shape of the first groove 20 is isosceles trapezoid, which can make the corrosion morphology on both sides of the first groove 20 consistent. Further, the shape of the vibration arm 2 is also isosceles trapezoid, and the central axis of the vibration arm 2 and the corresponding first groove 20 coincide.

[0028] Specifically, the width of the vibration arm 2 close to one end of the base body 1 is 80-125 um, preferably 90-120 um, and more preferably 100-120 um; the width of the other end is 70-120 um, preferably 80-115 um, and more preferably 90-110 um; the width of the first groove 20 close to one end (i.e. the large end) of the base body 1 is 60-120 um, preferably 70-105 um, and more preferably 78-96 um; the width of the other end (i.e. the small end) is 55-105 um, preferably 60-95 um, and more preferably 70-88 um; the difference between the small end and the large end is 2-20 um, preferably 4-16 um, and more preferably 4-12 um. Since the width difference between the two ends of the first groove 20 is small, the shape of the first groove 20 formed by etching on the vibration arm 2 is close to a rectangular shape. The thickness of the part of the vibration arm 2 connecting the two first grooves 20 on its upper and lower surfaces is relatively uniform in the x-axis direction, and has good rigidity. Table 1 shows the effect of the width difference between the two ends of the first groove 20 on the frequency (HZ) and the corresponding resistance CI (KΩ) of the quartz tuning fork wafer before weighting:

[0029] Table 1 Effect of the width difference between the two ends of the first groove on the frequency and the corresponding resistance CI of the quartz tuning fork wafer before weighting

[0030]

[0031] As can be seen from Table 1, when the width difference between the two ends of the first groove 20 is in the range of 0-20 um, as the width difference between the two ends gradually increases, the frequency of the quartz tuning fork wafer before weighting increases, and the resistance CI value decreases. Although the resistance CI is the smallest when the width difference is 20 um, the frequency before weighting is too high, which makes it difficult to perform the weighting and coarse adjustment process in actual production.

[0032] Please continue to refer to Figure 1 or Figure 2 Further, the upper surface and the lower surface of the vibration arm 2 close to one end of the base body 1 are also etched to form a second groove 21 in communication with the corresponding first groove 20, and the width of the second groove 21 gradually decreases in the direction away from the first groove 20, to facilitate wiring at the root of the vibration arm 2.

[0033] Specifically, the width of the large end of the second groove 21 is the same as the width of the large end of the first groove 20, both of which are 78-96um, and the width of the small end of the second groove 21 is 76-94um.

[0034] By setting the width of the large end of the second groove 21 to be the same as the width of the large end of the first groove 20, the size discontinuity between the first groove 20 and the second groove 21 is avoided, which can improve the electric field force efficiency of the vibrating arm 2 and reduce the resistance.

[0035] In this embodiment, the quartz tuning fork further comprises a folding arm 3 fixedly connected to one end of the base 1 away from the vibrating arm 2, and the base 1 is fixedly connected to the external wafer piece through the folding arm 3. The base 1 can be separated from the wafer piece by folding the wafer to break the folding arm 3. Specifically, after the quartz tuning fork is processed, the wafer is folded upwards to break the folding arm 3 to separate the quartz tuning fork from the wafer piece.

[0036] Further, the end of the folding arm 3 away from the base 1 has at least one folding notch 30, so that the folding arm 3 is easier to break at the folding notch 30, avoiding the wafer from being broken due to the need to apply a large force when folding the wafer because the strength of the folding arm 3 is too large.

[0037] Further, according to the relative relationship between the depth of the folding notch 30 and the thickness of the folding arm 3, the folding notch 30 has two setting modes on the folding arm 3, that is, when the depth of the folding notch 30 is equal to the thickness of the folding arm 3, the folding notch 30 penetrates the folding arm 3; when the depth of the folding notch 30 is less than the thickness of the folding arm 3, the folding notch 30 does not penetrate the folding arm 3. Preferably, in order to make the folding arm 3 breakable while having a certain strength, the depth of the folding notch 30 along the thickness direction of the folding arm 3 is less than the thickness of the folding arm 3, so as to avoid the quartz tuning fork from falling off the wafer piece during processing due to insufficient strength of the folding arm 3. More preferably, the folding notch 30 is a pair and is spaced apart on the upper surface of the folding arm 3, so that the force point can be determined according to the position of the folding notch 30.

[0038] As Figure 3 shown is a state diagram of the quartz tuning fork and the wafer piece connected through the folding arm 3. The quartz tuning fork and the wafer piece can be separated by breaking at the folding notch 30 of the folding arm 3, that is, the quartz tuning fork shown in Figure 1 is obtained.

[0039] In the embodiment, waist grooves 10 are arranged on two sides of the base body 1 respectively, the waist grooves 10 divide the base body 1 into a connecting part 11 and a fixing part 12 which are connected to each other, the connecting part 11 is fixedly connected with the vibrating arm 2, and the fixing part 12 is fixedly connected with an external wafer piece, so that the quartz tuning fork cannot fall off during processing.

[0040] The waist grooves 10 reduce the connecting area between the connecting part 11 and the fixing part 12, so that, during vibration of the quartz tuning fork, mechanical vibration transmitted from the connecting part 11 to the fixing part 12 through the vibrating arm 2 is attenuated at the waist grooves 10, so as to avoid more vibration from being transmitted to the fixing part 12, thereby improving the stability of the output frequency of the quartz tuning fork.

[0041] Further, the opening of the waist groove 10 is gradually enlarged outward from the central axis of the connecting part 11, so that the mechanical vibration transmitted from the connecting part 11 to the fixing part 12 is gradually attenuated, thereby reducing the vibration transmitted to the connecting part 11 and the fixing part 12, prolonging the service life of the quartz tuning fork.

[0042] Preferably, the inner wall of the waist groove 10 near the connecting part 11 is a curved surface 101 which is curved towards the connecting part 11, one end of the curved surface 101 is smoothly and transitionally connected with the side wall of the corresponding fixing part 101, and the other end is smoothly and transitionally connected with the remaining inner wall of the waist groove 10.

[0043] It can be understood that, by arranging the inner wall of the waist groove 10 near the connecting part 11 as the curved surface 101 which is curved towards the connecting part 11, the length of the inner wall of the waist groove 10 near the connecting part 11 can be greatly prolonged, so that the vibration of the connecting part 11 can be fully attenuated at the inner wall, thereby greatly reducing the mechanical vibration transmitted to the connecting part 11 and the fixing part 12.

[0044] In order to facilitate understanding of the scheme, the following will be described in combination with Figures 1-3 The working principle of the utility model will be described in detail as follows:

[0045] In the preparation of the quartz tuning fork, the first grooves 20 are etched in the middle of the upper and lower surfaces of the vibration arm 2 respectively, the central axis of the first grooves 20 coincides with the central axis of the corresponding vibration arm 2, and in particular, when the first grooves 20 are etched, the width of the first grooves 20 gradually increases in the direction opposite to the extension direction of the vibration arm 2, so that the distance between the two first grooves 20 on the upper and lower surfaces of the vibration arm 2 gradually increases in the direction opposite to the extension direction of the vibration arm 2, thereby gradually increasing the rigidity of the vibration arm 2 in the direction opposite to the extension direction of the vibration arm 2, and thus preventing the vibration arm 2 from being twisted from the root.

[0046] After the preparation of the quartz tuning fork is completed, the quartz tuning fork is folded upwards (in the positive direction of the z-axis, that is, perpendicular to the wafer sheet), so that the folded arm 3 is broken from the folding notch 30, thereby separating the prepared quartz tuning fork from the wafer sheet.

[0047] When the quartz tuning fork works, the mechanical vibration generated by the vibration arm 2 is transmitted to the fixed part 12 through the connecting part 11, and due to the waist groove 10 arranged at the connecting part 11 and the fixed part 12, the transmitted mechanical vibration is attenuated at the waist groove 10, so as to reduce the vibration transmitted to the fixed part 12, thereby improving the stability of the output frequency of the quartz tuning fork.

[0048] In summary, the quartz tuning fork provided by the utility model, because the width of the first grooves 20 etched on the vibration arm 2 gradually increases in the direction opposite to the extension direction of the vibration arm 2, so that the distance between the two first grooves 20 on the upper and lower surfaces of the vibration arm 2 gradually increases in the direction opposite to the extension direction of the vibration arm 2, thereby gradually increasing the rigidity of the vibration arm 2 in the direction opposite to the extension direction of the vibration arm 2, and thus preventing the vibration arm 2 from being twisted from the root.

[0049] It should be noted that although the utility model is disclosed as above with specific embodiments, the above embodiments are not used to limit the utility model, and those skilled in the art can make various changes and decorations without departing from the spirit and scope of the utility model, therefore the protection scope of the utility model is defined by the scope of claims.

Claims

1. A quartz tuning fork, characterized by, The vibration arm (2) includes a base (1) and two vibration arms (2) extending outward from one end of the base (1), the upper and lower surfaces of the vibration arm (2) are each corroded to form a first groove (20), the width of the first groove (20) gradually increases in the direction close to the base (1).

2. A quartz tuning fork according to claim 1, wherein The opening shape of the first groove (20) is isosceles trapezoidal.

3. A quartz tuning fork according to claim 2, wherein The width difference between the small end and the large end of the first groove (20) is 2-20um.

4. A quartz tuning fork according to any one of claims 1 to 3, characterized in that The shape of the vibration arm (2) is isosceles trapezoidal, and the central axis of the vibration arm (2) coincides with the central axis of the corresponding first groove (20).

5. A quartz tuning fork according to claim 4, wherein The width of the vibration arm (2) close to the base (1) is 80-125um, and the width of the other end is 70-120um.

6. A quartz tuning fork according to claim 1, wherein The upper and lower surfaces of the vibration arm (2) close to the base (1) are each corroded to form a second groove (21) in communication with the corresponding first groove (20), the width of the second groove (21) gradually decreases in the direction away from the corresponding first groove (20).

7. A quartz tuning fork according to claim 1, wherein It also includes a folding arm (3) fixedly connected to the end of the base (1) away from the vibration arm (2).

8. A quartz tuning fork according to claim 7, wherein The end of the folding arm (3) away from the base (1) has at least one folding notch (30).

9. A quartz tuning fork according to claim 8, wherein The depth of the folding notch (30) in the thickness direction of the folding arm (3) is less than the thickness of the folding arm (3).

10. A quartz tuning fork according to claim 9, wherein The folding notch (30) is a pair of notches and is spaced apart on the upper surface of the folding arm (3).

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