BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is illustrative of a cross-sectional view of embodiment of surface mounting piezoelectric oscillator related to this invention.
FIG. 2 is illustrative of a fixation of the base print board 10 and sub print board 40 by the first metal strut 50.
FIG. 3 is illustrative of a fixation of the base print board 10 and sub print board 40 by the second metal strut 60.
FIG. 4 is illustrative of a fixation of the base print board 10 and sub print board 40 by the third metal strut 70.
FIG. 5 is illustrative of to change piezoelectric oscillator 80 with two or four lead terminals into surface mounting piezoelectric oscillator 80.
FIG. 6 is illustrative of transformation samples of a plate-shape metal strut that is mentioned above.
DETAILED DESCRIPTION OF ILLUSTRATIVE EMBODIMENTS
Embodying Example
FIG. 1 is a cross-section view showing an embodying example of the surface mounting piezoelectric oscillator. A piezoelectric oscillator 100 consists of a base print board 10 and a sub print board 40. Some of electric parts 31 for an oscillating circuit are fixed to the base print board 10 by solder. Some of the electric parts 31 for the oscillating circuit and a crystal oscillator 32 are fixed to the sub print board 40 by solder. In order for the piezoelectric oscillator to be mounted on the surface at the circuit oscillator, an external terminal 15 which are set 4 or 6 areas are set on the bottom or side of base print board 10.
Also, an edge of a first metal strut 50 which is formed by brass and others is inserted to a concave portion 11 and fixed by solder 21 at the base print board 10. The other edge of the first metal strut 50 is fixed to the sub print board 40 by solder 21. A metal case 48 covers all as it seals the two-tiered base print board 10 and the sub print board 40. The size of piezoelectric oscillator 100 of such features is 3 mm corner to 50 mm corner.
FIG. 2 shows fixation of the base print board 10 and the sub print board 40 by the first metal strut 50. FIG. 2A is a perspective-view of the first metal strut 50. FIG. 2B shows fixation of the base print board 10 and the first metal strut 50, and the sub print board 40 and the first metal strut 50.
As FIG. 2 shows that the first metal strut 50 has a first flange 51 and a second flange 53 at both ends of brass shaft 54. The brass shaft 54 has a first shaft 52 and a second shaft 56 which penetrated both the first flange 51 and the second flange 53. The diameter of the brass shaft is from about 0.03 mm to 1 mm, and the diameter of first flange 51 and second flange 53 is 0.04 mm to 3 mm which should be twice as much as the diameter of the brass shaft 54.
As FIG. 2 shows, there is the concave portion 11 at the base print board 10 into which the first shaft 52 can be inserted. The base print board 10 is composed of a grass epoxy material. The thickness of base print board 10 is about 0.6 mm to 3 mm, and the depth of concave portion 11 is 30 to 90% of thickness of the base print board 10. The diameter of concave portion 11 is smaller than of the first flange 51 and same as or bigger than shaft 52. A flat mill is used for making the concave portion 11 at the base print board 10. The concave portion 11 is coated with copper coat 12. An external terminal 15 and the copper coat 12 are electrically connected. First flange 51 of the metal strut 50 is fixed to the copper coat 12 by solder. Instead of using solder 21, electrically conductive adhesive can be used to fix them. Since concave portion 11 is not penetrated to the external terminal 15 end, solder 21 does not melt and leak by heat. When first flange 51 and the copper coat 12 are attached tenaciously, they can be fixed by nonconductive adhesive instead of by solder 21.
The sub print board 40 has a hole 41 which is completely penetrated through to the other side of the board for inserting a second shaft 56. The hole can be a concave portion instead of penetrated hole. The diameter of the hole 41 is smaller than the diameter of the second flange 53 and the same or bigger diameter than the second shaft 56. The sub print board 40 is a glass epoxy material and a thickness of the sub print board 40 is about 0.6 mm to 3 mm. The hole 41 is coated with copper coat 43. The second shaft 56 of the first metal strut 50 is fixed to the copper coat 43 formed at the surface of the sub print board 40 by solder and connected electrically. Thus, the electric power of the external terminal 15 reaches the sub print board 40.
FIG. 3 shows a fixation of the base print board 10 and the sub print board 40 by a second metal strut 60. FIG. 3A shows a fixation of the base print board 10 and the sub print board 40 by the second metal strut 60. FIG. 3B shows a fixation of the base print board 10 and the sub print board 40 by using the metal strut 60 in another process.
A difference between the second metal strut 60 drawn in FIG. 3A and the first metal strut 50 drawn in FIG. 2B is the presence of the first flange 51. Other components are substantially the same. The concave portion 11 is formed on the base print board 10 for inserting brass shaft 64. The thickness of the base print board 10 is about from 0.6 mm to 3 mm, and the depth of the concave portion 11 is 30 to 90% of the thickness of the base print board 10. The diameter of the concave portion 11 is the same diameter of the brass shaft 64 or bigger than that. The concave portion 11 is coated with the copper coat 12. The external terminal 15 and the copper coat 12 is electrically connected. The brass shaft 64 of the metal strut 60 is fixed to the copper coat 12 by solder. Since the concave portion 11 is not penetrated to the external terminal 15 end, solder 21 does not melt and leak by heat. Note that compared to FIG. 2B, because there is no first flange 51 at the second metal strut 60, it is weak against vibration but it is low cost to manufacture. The configuration of the second shaft 66 of the metal strut 60 inserted to the hole 41 of the sub print board 40 and fixed by the solder 21 is the same configuration as FIG. 2B.
In FIG. 3B, structure of the base print board 10 is different from FIG. 3A. A penetrated hole 19 is formed instead of the concave portion 11 on the base print board 10. A cap 68 with flange is inserted into the penetrated hole 19. The cap 68 with flange is composed of a heat resistance non-conductor such as a thermosetting plastic. A diameter of the flange is smaller than an area where the copper coat 12 is formed. Also, an insert hole (concave) 69, where a brass shaft 64 of the second metal strut 60 is inserted, is formed on a cap 68 with flange. The insert hole 69 does not penetrate a cap 68 with flange completely. The copper coat 12 is finished around the penetrated hole 69. The external terminal 15 and copper coat 12 are electrically connected. The brass shaft 64 of the second metal strut 60 and the copper coat 12 is fixed by the solder 21. The penetrated hole 19 is sealed with the cap 68, and also the insert hole 69 formed on the cap 68 is not fully penetrated, therefore, the solder 21 does not melt and leak out. The external terminal 15 of FIG. 3B, which has the penetrated hole 19, is shorter than the one of FIG. 3A. Because it avoids contact failure, the bigger external terminal is recommended when it is mounted to the circuit board. Note that the configuration of the second shaft 66 of the metal strut 60 inserted to a hole 41 of the sub print board 40 and fixed by the solder 21 is the same configuration as FIG. 2B.
FIG. 4 shows fixation of the base print board 10 and the sub print board 40 by a third metal strut 70. FIG. 4A is a perspective view of the third metal strut 70 and FIG. 4B shows fixation of the base print board 10 and the third metal strut 70, and the sub print board 40 and the third metal strut 70.
As show in FIG. 4A, the third metal strut 70 is bent 90 degrees in the middle of the brass shaft 74 and has a first fold 71 and a second fold 73. The diameter of the brass shaft 74 is 0.03 mm to 1 mm. The length between the first fold 71 and second fold 73 is 1 mm to 3 mm.
As shown in FIG. 4B, a concave portion 18 is formed on the base print board 10 to insert into the first fold 71. The thickness of the base print board 10 is 0.6 mm to 3 mm, and the depth of the concave portion 18 is formed 30 to 90% of the thickness of the base print board 10. The width of the concave portion 18 is bigger than or the same size as the diameter of the first fold 71. The concave portion 18 is thinner than the concave portion 11 drawn in FIG. 2. Therefore, the copper coat 19 is finished not only around the concave 18 but also the concave portion 18 itself. The external terminal 15 and the copper coat 19 are electrically connected. The first fold 17 of the third metal strut 70 and the copper coat 19 are fixed by the solder 21. Because the concave portion 18 is not fully penetrated to the external terminal 15 end of the base print board 10, the solder 21 does not melt and leak out.
A concave 42 is formed on the sub print board 40 for inserting the second fold 73. The width of concave 42 is bigger than or the same size as the width of second fold 73. The sub print board 40 is comprised of a glass epoxy material and a thickness of the sub print board 40 is 0.6 mm to 3 mm. The depth of the concave 42 is formed 30 to 90% of the thickness of the sub print board 40. The copper coat 44 is finished both concave 42 itself and around the concave. The second fold 73 and copper coat 44 is electrically connected. Thus electricity of the external terminal 16 reaches the sub print board 40. As this configuration, the sub print board 40 is supported by the base print board 10 as two-tiered. The first fold 71 or the second fold 73 become stronger against vibration by bending because the wide area of metal strut attaches to the concave portion 18 and 42. Also, it is cost less because it is just to fold the metal.
FIG. 5 shows changing the piezoelectric oscillator with lead terminal 80 which has two or four lead terminals into the surface mounting piezoelectric oscillator 80. FIG. 3A shows the piezoelectric oscillator with lead terminal 80. FIG. 3B is a cross-sectional view of the surface mounting piezoelectric oscillator 80. In the past, the piezoelectric oscillator with lead terminal 80 is used as a surface mounting piezoelectric oscillator by making holes to a base print board and penetrating shortened lead terminal to the hole. However, on this features, there is a possibility that lead terminals stick out and be exposed from the base print board or may cause a short out on the surface mounted circuit board.
The piezoelectric oscillator with lead terminal 80 illustrated in FIG. 5A is equipped with a chassis 88 with crystal oscillator, a seal board 86 to seal the chassis, and four lead terminals 84 sticking out from the seal board 86. The four lead terminals 84 are the same as the brass shaft 74 showed in FIG. 4. The base print board 10 drawn in FIG. 5B is the same as the base print board 10 drawn in FIG. 4. In FIG. 5B, the four lead terminals 84 of the piezoelectric oscillator with lead terminal 80 are bended to 90 degrees in the middle.
A concave portion 18 is formed on the base print board 10 for inserting bended lead terminal 84. The thickness of the base print board 10 is 0.6 mm to 3 mm, and the depth of the concave portion 18 is 30 to 90% of the base-print 10. The width of the concave portion 18 is the same diameter or bigger than the lead terminal 84. The copper coat 19 is finished not only around the concave portion 18 but also the concave portion 18 itself. The external terminal 15 and the copper coat 19 are electrically connected. The lead terminal 84 and the copper coat 19 are fixed by a shortened solder 21. Because the concave portion 18 is not fully penetrated to the external terminal 15 end of the base print board 10, the solder 21 does not melt and leak out. Also, the lead terminal 84 does not stick out at the side of the external terminal 15 on the base print board 10.
FIG. 6 shows transformation samples of a metal strut. The metal strut as explained above is cylinder or wire shape, but it can be a plate shape as well. The piezoelectric oscillator often requires high reliability and a long term performance guarantee. Especially the support stiffness toward a lateral direction of the metal strut is low and when the piezoelectric oscillator receives an unexpected high impact, the metal strut may get transformed, and it enormously affects reliability and electrical performance.
If the metal strut touches a case because of the elasticity of the metal strut or transformation caused by high impact, an electrical short or diffusion of heat to the case may occur and can cause change of capability or destroy circuit parts. In preparation for such a case, a metal strut with plates shape may be prepared.
FIG. 6 is the metal strut 91 which has a flange on the side of the base print board 10 and a folded board part on the side of the sub print board 40. Note that a board protruding portion 91-2 has some short width protruding. FIG. 6B shows the metal strut 91 has a flange on the base print board 10 side and the sub print board 40 side. As shown in FIG. 6B, short width protruding portion are formed on the board because if the protruding portion of the board are formed same width of the board, they might be broken and cut by the concave portion of the sub print board 40. The protruding portion 93-1 of the base print board 10 is the same spec as previous protruding portion.
FIG. 6C is a metal strut 95 having a bend in its board of sub print board 40 side. Note that some short width protruding portion 95-2 are formed on the side of the base print board 10 side. This is because if the protruding portion 95-2 is formed full width of the board, they might be broken and cut by the concave of the base print board 10. FIG. 6D shows the metal strut 95 having bended both sides of base print board 10 side and sub print board 40 side.
For each metal strut shown in FIG. 6, a concave portion is formed on the base print board 10. Also, the concave itself and around the concave are finished with the copper coat. The concave part is not fully penetrated to the external terminal 15 side of the base print board 10 so that the solder 21 does not melt and leak out by heat from it. Because of this, high reliable piezoelectric oscillator with improved impact resistance can be made.
The piezoelectric oscillators of this embodiment may be Temperature Compensated Crystal Oscillators (TCXO), Voltage Controlled Crystal Oscillator (VCXO), Oven-Controlled Crystal Oscillator (OCXO), or Oscillator with lead terminal, but can also be of a surface mounting terminal configuration of not only an oscillator but also an LC oscillator, SAW oscillator, or other electric parts. As piezoelectric material, crystal oscillators or ceramics can be used. Also, as explained with respect to the metal strut part, it can be any material if it is conductive material, for example, conductive plastic can be used.
Patent Application
20080079505
