JP3864056B2 - Crystal oscillator - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a crystal unit for high stability, and more particularly to a crystal unit whose impact characteristics are improved while maintaining miniaturization.
[0002]
[Prior art]
(Background of the Invention) Crystal resonators are well known as frequency and time reference sources. For example, high-stability crystal resonators using a thermostatic chamber or the like with high frequency stability for communication devices are used. is there. In recent years, there has been a demand for downsizing, particularly, low profile in these products.
[0003]
(Example of Prior Art) FIGS. 9 and 10 are views of a crystal resonator for explaining a conventional example, FIG. 9 is a sectional view excluding a cover, and FIG. 10 is a plan view excluding a cover and a metal base. .
The quartz resonator is made of, for example, a circular quartz piece 1 having an AT cut, and the main surface thereof is held facing the surface of the metal base 2. Excitation electrodes 3 (ab) are formed on both main surfaces of the crystal piece 1, and the extraction electrodes 4 (ab) are extended to end surfaces (referred to as both end surfaces) of the outer peripheral ends of both ends. Alternatively, a conductive agent mainly composed of, for example, silver (Ag) that is connected to the extraction electrode 4 (ab) is applied to both end faces. In addition, it is set as the end surface electrode 5 including these.
[0004]
The metal base 2 has a pair of lead terminals 8 (ab) that are hermetically sealed with glass 6 and penetrate the base body, and have tips that are nail heads 7 protruding on the surface. Each horizontal portion of the L-shaped supporter 9 (ab) facing the inner surface is connected to the nail head portion 7 as the tip of each lead terminal 8 (ab) by laser welding.
[0005]
Then, a metal hammer 10 containing, for example, germanium (Ge) is applied to the opposite surface of the supporter 9 (ab), and bonded to both end surfaces of the crystal piece 1 by so-called thermocompression (so-called brazing and brazing). Here, both end faces are notched in a straight line to clearly indicate the axial direction of the crystal axis (XYZ) and facilitate thermocompression bonding. Here, the direction connecting both end faces is about +30 degrees or −30 degrees from the Z ′ axis of the crystal axis (XY′Z ′) as AT cut, and the frequency change with respect to stress is the most. The stress sensitivity zero axis in the small direction.
[0006]
As shown in FIG. 11, the AT cut is a cutting angle in which the principal plane perpendicular to the Y axis of the crystal axis (XYZ) is inclined from the Z axis to the Y axis by about 35 degrees 15 minutes. This axis is the Y′Z ′ axis.
[0007]
Then, after holding the crystal piece 1 by brazing with a hammer 10, a cover (not shown) is joined to the metal base 2 by cold pressure welding, resistance welding or the like and hermetically sealed. In the figure, the flange formed on the outer periphery of the metal base 2 for cold welding or resistance welding is omitted. Then, the crystal resonator is housed in a thermostatic chamber to form a highly stable crystal oscillator.
[0008]
In such a case, since both end surfaces of the crystal piece 1 are held by brazing using the hammer 10, the influence on the vibration displacement is reduced as compared with the case where the main surface is held, for example. Moreover, compared with the case where it hold | maintains using the electrically conductive adhesive which is not shown in figure, generation | occurrence | production of the stress by the shrinkage | contraction at the time of hardening, etc. is prevented. Therefore, the vibration characteristics (electrical characteristics) of the crystal resonator are improved, and for example, the crystal impedance (CI) is reduced.
[0009]
Further, the tip of the lead terminal 8 is projected as a nail head 7 on the surface of the metal base 2, and each horizontal portion of the L-shaped supporter 9 (ab) is connected. Therefore, compared with the conventional case where the tip of the lead terminal having the same diameter protrudes from the surface of the metal base 2 and spot support welding is performed on a flat supporter (not shown), the height dimension is particularly small and low. Promote downturning.
[0010]
[Problems to be solved by the invention]
(Problems of the prior art) However, the crystal resonator having the above structure holds both end faces of the crystal piece 1 (holds two points). There is a problem that it is weak and inferior in so-called impact resistance. In particular, in this case, in order to promote a reduction in height, the tip of the lead terminal 8 is joined point-wise by laser (beam) welding as the nail head 7.
[0011]
Therefore, the bonding strength is weaker than in the conventional case where the lead terminals 8 have the same diameter, and stress is generated in the crystal piece by the rotational moment centering on the joint point between the nail head 7 and the supporter 9 (ab). Alternatively, there is a problem that the crystal piece tends to roll about the straight line connecting both end faces, and the impact resistance is deteriorated.
[0012]
For this reason, it has been considered that the other end surfaces orthogonal to the both end surfaces of the crystal piece 1 are also held by brazing so as to hold the four-point end surfaces. However, in this case, since the other end surfaces of the crystal piece 1 do not need to be electrically connected, there is a problem that the holding by brazing using the hammer 10 or the like is economically wasteful.
[0013]
(Object of the Invention) An object of the present invention is to provide an economical crystal resonator while maintaining its electrical characteristics, impact resistance and miniaturization.
[0014]
[Means for Solving the Problems]
According to the present invention, as shown in the claims (Claim 1), the crystal piece having the end face electrodes electrically connected to the excitation electrode and the extraction electrode provided on both main faces on both end faces of the outer periphery, and A metal base having a lead terminal with a nail head projecting on the surface facing the main surface of the crystal piece; and an L-shaped first supporter formed by joining a horizontal portion to the nail head. In the quartz resonator, the both end faces of the outer peripheral portion having the end face electrode are linearly cut out to clearly indicate the axial direction and minimize the change of the vibration frequency with respect to the stress. The outer peripheral end face and the supporter are connected to each other by thermocompression bonding using a germanium containing germanium, and both outer peripheral end faces other than the outer peripheral end face having the end face electrode are mechanically connected to the second supporter only by an adhesive. And
[0015]
[Action]
In the present invention, since the other end surfaces are mechanically held in addition to being electrically and mechanically connected to both end surfaces having the end surface electrodes, the holding strength is increased. And since all hold | maintain an end surface, the influence with respect to a vibration displacement is made small. Furthermore, since the end surfaces that are held only mechanically are connected using an adhesive, the cost is lower than brazing using a hammer. Further, both end faces of the outer peripheral portion having the end face electrodes are notched in a straight line, so that the axial direction is clearly shown and thermocompression bonding is facilitated. An embodiment of the present invention will be described below.
[0016]
[First embodiment]
1 and 2 are diagrams for explaining an embodiment of the present invention. FIG. 1 is a plan view of a crystal resonator excluding a cover and a metal base, and FIG. 2 is a plan view of a metal base excluding a flange. is there. In addition, the same number is attached | subjected to the same part as a prior art example figure, and the description is abbreviate | omitted or abbreviate | omitted.
As described above, the quartz resonator has the excitation electrode 3 (ab) on both principal surfaces as an AT cut, and the end surface electrode 5 connected to the excitation electrode 3 (ab) on one end surface serving as the zero axis of stress sensitivity. It consists of a circular crystal piece 1. Then, a supporter connected to the nail head 7 of the lead terminal 8 (ab) by brazing using the hammer 10 with the main surface of the crystal piece 1 facing the metal base 2 (for convenience, it is referred to as a first supporter). ) 9 (ab) is held with both end surfaces electrically and mechanically connected (see FIG. 9).
[0017]
In this embodiment, a pair of lead terminals 8 (cd) is further added in a direction orthogonal to the pair of airtight lead terminals 8 (ab) of the metal base 2. And the horizontal part of the 2nd supporter 9 (cd) made into the above-mentioned L shape is connected to the nail head part 7 of each lead terminal 8 (cd), and the other both ends orthogonal to one both end surfaces of crystal piece 1 The surfaces are mechanically connected by the adhesive 11 around the end surface.
[0018]
With such a configuration, the brazing using the hammer 10 is provided on one end face and connected to the end face electrode 5 reaching the excitation electrode 3 (ab), so that the electrical connection is ensured and the crystal piece 1 is excited. Since the other end surfaces of the crystal piece 1 orthogonal to the one end surfaces are connected by the adhesive 11, the four-end end surfaces that are geometrically most stable in combination with the one end surfaces are obtained.
[0019]
Therefore, compared with the conventional two-point end face holding, the joint strength is also increased as a whole, and the rotational moment around the joint point between the nail head 7 and the supporter 9 is weakened to prevent the crystal piece 1 from being stressed. Also, rolls around a straight line connecting one end face are prevented. And the retention strength of the crystal piece 1 is raised and impact resistance is improved. Further, since the four end faces of the crystal piece 1 are basically held, the influence on the vibration displacement is small, and the electrical characteristics (vibration characteristics) such as CI are maintained.
[0020]
Note that the adhesive 11 that connects the other end faces is somewhat applied to both main surfaces by wraparound or the like, but the vibration characteristics are maintained. That is, in this embodiment, one end face on which the end face electrode 5 is formed is +30 (or −30) degrees inclined from the Z ′ axis, and the other end face only for mechanical holding is in the orthogonal direction. Therefore, the direction connecting the other end faces deviates from the X-axis direction, which is the displacement direction of vibration, so that the influence of the application of the adhesive 11 on the main surface is small, and the vibration characteristics are maintained.
[0021]
[Second embodiment]
FIG. 3 is a plan view of a crystal resonator for explaining a second embodiment of the present invention. In addition, description of the same part as a previous Example is abbreviate | omitted.
In the first embodiment, although the direction connecting one end face where the end face electrode 5 is formed is electrically and mechanically held as the stress sensitivity zero axis, the other end face orthogonal to this is held basically. 4 points end face holding. However, the direction connecting the other end faces is not the zero axis of the stress sensitivity, and the secular change characteristic is deteriorated by changing the vibration frequency due to the change of the vibration frequency due to the stress, for example, the change of the fixing strength of the adhesive 11.
[0022]
In the second embodiment, this point is improved. One end face of the other end orthogonal to the other end face orthogonal to the one end face having a stress sensitivity zero axis as an electrical / mechanical connection by brazing using a hammer. Only the adhesive 11 is connected to the second supporter 9c and held.
[0023]
In this way, since only one end is held between the other end faces orthogonal to one end face having the end face electrode 5, no stress is basically generated between the end faces. Therefore, the secular change characteristic by the stress sensitivity characteristic can be improved, the holding strength can be increased, and the impact resistance can be improved.
[0024]
[Third embodiment]
FIG. 4 is a plan view of a crystal unit for explaining the third embodiment of the present invention, and a description of the same parts as those of the previous embodiment is omitted.
The third embodiment improves the deterioration of the secular change characteristic due to the stress sensitivity characteristic of the first embodiment as in the second embodiment. That is, in the third embodiment, one end face in a direction inclined by +30 degrees from the stress sensitivity zero axis, for example, the Z ′ axis, is electrically and mechanically connected by brazing using a hammer. Here, the other end faces in the direction inclined by −30 degrees from the other stress sensitivity axis, that is, the Z ′ axis, are mechanically connected only to the second supporter 9 (cd) by the adhesive 11.
[0025]
In such a case, both of the directions connecting both end surfaces electrically and mechanically connected by brazing and both end surfaces connected only mechanically by the adhesive 11 are defined as zero axes of stress sensitivity. For example, the linear direction connecting the supporters 9a and 9d or 9b and 9c is at the center of the largest vibration displacement, and in this example, the excitation electrode 3 (ab) that is the vibration region is removed. Reduce change. Therefore, a change in vibration frequency due to a stress change is prevented, the four-point end face holding has symmetry, and the holding strength is further increased to improve the impact resistance.
[0026]
[Fourth embodiment]
FIG. 5 is a plan view of a crystal unit for explaining the fourth embodiment of the present invention, and the description of the same parts as those of the previous embodiment is omitted.
Unlike the first to third embodiments, the fourth embodiment differs from the first to third embodiments in that the end face electrode 5 of the crystal piece is not both end faces of the stress sensitivity zero axis, but both end faces 120 degrees away from the center by brazing, so that electrical and mechanical Connect to. Then, the end face that is 120 degrees away from each end face electrode 5 is mechanically connected to the second supporter 9c by the adhesive 11 and held.
[0027]
In such a case, since the geometrically stable three-point end face is retained, the impact resistance is improved. As described above, the straight line connecting the end faces deviates from the central vibration region , thereby reducing the influence of stress on the vibration frequency.
[0028]
[Other matters]
In the above embodiment, the crystal piece 1 is described as an AT cut, but an SC cut may be used as long as it is a thickness-shear vibration state. However, the stress sensitivity axis in this case is an axial direction inclined by +8 degrees from the Z ′ to the X ′ direction of the crystal axis (X′Y ″ Z ′) of SC cut by two rotations.
[0029]
As shown in FIG. 6, the SC cut is performed by rotating the principal plane perpendicular to the Y-axis of the crystal axis about 22 degrees from the X-axis to the Y-axis around the Z-axis. The rotation is about 34 degrees in the direction of a new Y ′ axis (not shown) from the Z axis around the axis.
[0030]
Moreover, although it was set as the brazing by the metal hammer 10, silver (Ag) etc. may be sufficient as a glaze material, and what is necessary is just a metal. The second supporter 9 (cd) is connected to the nail head 7 of the airtight lead terminal 8 (cd), but is directly connected to the metal base 2 to remove the lead terminal 8 (cd). You can do it.
[0031]
The second supporter 9 (cd) has an L-shaped flat plate shape. For example, as shown in FIG. 7, the second supporter 9 (cd) is provided with an inclined portion for temporarily holding the outer peripheral portion of the crystal piece 1 and the end face of the crystal piece 1. May be provided so that the adhesive is applied from the outside centering on the end face (FIG. 8). In this way, the crystal piece is stabilized when the adhesive is applied, and at the same time, the application work centering on the end face is facilitated.
[0032]
【The invention's effect】
The present invention includes a crystal piece having end face electrodes electrically connected to an excitation electrode and an extraction electrode provided on both main surfaces on both end surfaces of the outer peripheral portion, and the main surface and the surface of the crystal piece are opposed to each other on the surface. A crystal resonator comprising a metal base having a lead terminal protruding from the head and an L-shaped first supporter formed by joining a horizontal portion to the nail head, and an outer peripheral portion having the end face electrode Both end faces are linearly cut to clearly indicate the axial direction and minimize the change in vibration frequency with respect to stress, and the outer peripheral end face having the end face electrode and the supporter are made of a metal cage containing germanium. Since the connection is made by thermocompression bonding and both end faces of the outer peripheral part other than the end face of the outer peripheral part having the end face electrodes are mechanically connected to the second supporter by an adhesive, electrical characteristics, impact resistance and miniaturization are achieved. Maintain and pass It is possible to provide a specific crystal oscillator.
[Brief description of the drawings]
FIG. 1 is a plan view of a crystal resonator excluding a cover and a metal base, illustrating a first embodiment of the present invention.
FIG. 2 is a plan view of a metal base for explaining the first embodiment of the present invention.
FIG. 3 is a plan view of a crystal resonator for explaining a second embodiment of the present invention.
FIG. 4 is a plan view of a crystal resonator for explaining a third embodiment of the present invention.
FIG. 5 is a plan view of a crystal resonator for explaining a fourth embodiment of the present invention.
FIG. 6 is a cut orientation view of a crystal piece having an SC cut to which the present invention is applied.
FIG. 7 is another example of the second supporter in each embodiment of the present invention.
FIG. 8 is an application diagram of an adhesive according to another example of the second supporter in each embodiment of the present invention.
FIG. 9 is a cross-sectional view of a crystal resonator for explaining a conventional example.
FIG. 10 is a plan view of a crystal resonator illustrating a conventional example.
FIG. 11 is a cut orientation view of a crystal piece having an AT cut applied to the present invention while explaining a conventional example.
[Explanation of symbols]
1 crystal piece, 2 metal base, 3 excitation electrode, 4 extraction electrode, 5 end face electrode, 6 glass, 7 nail head, 8 lead terminal, 9 supporter, 10 metal cage, 11 adhesive, 12 slit.

Claims (5)

A crystal piece having end face electrodes electrically connected to the excitation electrode and the extraction electrode provided on both main faces on both outer peripheral surfaces, and the main face of the crystal piece face each other and the nail head protrudes from the surface. In the crystal resonator comprising the metal base having the lead terminals and the L-shaped first supporter formed by joining the horizontal portion to the nail head, both end faces of the outer peripheral portion having the end face electrodes are straight lines. a direction to minimize the change in the oscillation frequency with respect to stress with Jo in the cutout by explicitly axial, thermocompression bonding the outer peripheral end face and the supporter that by the gold braze containing germanium having the end surface electrode crystal oscillator connected, characterized by being connected only to the mechanical outer peripheral portion end surfaces other than the outer peripheral end face having the end surface electrode on the second supporter by adhesive by. The crystal piece is a AT-cut quartz crystal of 請 Motomeko 1 outer circumference end faces are inclined in the X-axis direction from the crystal axis Z 'axis of an AT-cut with the end surface electrode. The crystal piece is a SC-cut quartz crystal of 請 Motomeko 1 outer circumference end faces are inclined 'from the axis X' Z from the crystal axis to SC-cut in the axial direction with the end surface electrode. 2. The crystal resonator according to claim 1, wherein the nail head portion of the lead terminal and the horizontal portion of the first supporter are laser welded. 2. The crystal resonator according to claim 1, wherein the second supporter has a flat plate shape and has a slit through which an outer peripheral end face of the crystal piece is exposed.

Images