US2293485A - Piezoelectric device holder - Google Patents

Description

PZEZOELEGTRIC DEVICE HOLDER.

Filed NOV. 4, 1941 Z9 Charles F. Baldwin,

by Wan/1 75 His Attohneg.

Patented Aug. 18, 1942 PIEZOELECTRIC DEVICE HOLDER Charles F. Baldwin, Schenectady, N. Y., assignor to General Electric Company, a corporation of New York Application November 4, 1941, Serial No. 417,816 4 Claims. (Cl. 17132'l) My invention relates to piezoelectric devices, and has for an object to provide an improved and simplified holder for a plurality of such devices.

When a plurality of high frequency piezoelectric devices is arranged in a single holder with a double-faced electrode interposed between each pair of adjacent piezoelectric devices, difficulties arise in providing suitable connections from the respective electrodes to terminals on the holder.

Quartz crystal vibrators for operation at high frequencies are thin. For example, such vi,- brators for operation in the range from 2 to 8 megacycles, may be from fifty to twelve thousandths of an inch thick. Electrodes for such devices may conveniently be made 1 3' inch or less in thickness, so that a large number of such devices and electrodes may be stacked in small space. For example, a typical assembly of twenty-five quartz crystal vibrators and twenty-six electrodes stacked alternately may be less than 3 inches long. Standard pin terminals are usually mounted not less than A inch apart, so that a single row of such terminals is twice as long as the stack, thereby making connections diificult. If twenty-seven such terminals be spaced in three rows and nine columns, the overall length can readily be made the same as the stack and interconnection is facilitated.

It is an object of my invention to provide such an assembly of piezoelectric devices in a holder having a plurality of rows and columns of terminals with improved and simplified means whereby connections may be completed between electrodes and corresponding terminals with minimum possibility of short circuits between electrodes.

It is also an object of my invention to provide such an improved arrangement which occupies a minimum of space and is easily manufactured and rugged in use.

The features of my invention which I believe to be novel are set forth with particularity in the appended claims. My invention itself, both as to its organization and manner of operation, together with further objects and advantages thereof may best be understood by reference to the following descriptiontaken in connection with the accompanying drawing in which Fig. l is an elevational side view partly in section, of one modification of my invention, and Fig. 2 is a sectional view in perspective of one end of the modification of Fig. 1.

In Fig. 1 there is illustrated a holder which includes a lower rectangular wall II] with integral sides II and right and left ends I2 and I3 respectively. A lid I4 is fastened to the sides II and ends I2 and I3 of the holder by means of suitable screws I5. The Wall I0, sides II, ends I2 and I3, and the lid I4 are all formed of insulating material, preferably a moldable thermosetting resin. The lid I4 may be provided with shoulders I6 which engage the sides II and ends I2 and I3 of the holder to form a good joint therebetween. If desired, a gasket may be provided between the lid I4 and the holder for sealing the holder against the entrance of moisture and foreign matter.

Within the lower portion of the holder I0, including the lower wall I0, sides II, and ends I2 and I3, a plurality of electrodes I1, I8, I9 20, 2| are placed alternately between a plurality of quartz crystal vibrators 22, 23, 24 25, 26. The electrodes may be of any suitable form and, as shown, are rectangular, each electrode having each face centrally recessed a small amount. A spring 21 is placed between the right end I2 of the holder and the adjacentend of the stack of electrodes I'I, I8, I9 20, 2I and vibrators 22, 23, 24 25, 26 to maintain such stack closely pressed together and held against the opposite end I3 of the holder,

A connection, to be described in detail later, is provided from each of the electrodes Il, I8, I9 20, 2I to a corresponding pin terminal, such as connection 28 from electrode Il to terminal 29. The terminal 29 and the space between it and the adjacent terminal 30 is considerably greater than the thickness of electrode I1 and the adjacent quartz crystal vibrator 22, and is much greater than the thickness of vibrator 26 and electrode 2|. As shown in Fig. 1 the terminals which are shown are connected to every third electrode. As may be seen more clearly in Fig. 2, behind the terminal 29 there is a second similar pin terminal 3I and a third terminal 32.

Ribs 33 and 34 are formed inside the holder integral with the lower wall I0, and extending longitudinally from one end I2 tothe outer end I3 of the holder. Three channels 35, 36 and 31 are formed in the holder bythe ribs 33 and 34, and in these channels the inside ends of the terminals 29, 3I and 32 and the respective connections from such terminals to the corresponding electrodes II, I8 "and I9 are accommodated.

The ribs 33 and 34 are of suflicient depth to maintain the stack of electrodes and vibrators such terminals underneath such triads.

' thickness.

spaced from the terminals 29, 3| and 32 and the corresponding connections, so that undesirable short circuits therebetween are prevented. By the use of these ribs 33 and 34 it is possible to arrange the terminals in rows and columns, as illustrated, and to make connections from each of the terminals in a single column to a corresponding one of three adjacent electrodes without having any one terminal or corresponding connection'short circuit with any other connection.

As may be seen clearly in Fig. 2, in which the right end electrode l1 and the adjacent vibrator 22 are partially broken away at the lower right hand corner, the connecting conductor 28 is embedded in the end electrode I! and extends through the channel 35, underneaththe second and third electrodes l8 and H! to the terminal 29 into which the conductor 28 is conductively fastened, as by soldering. A similar connecting conductor 38 is embedded in the second electrode l8 and extends through the channel 36, underneath the third electrode l9 to the terminal 3|, into which this conductor 38 is conductively fastened. A third similar connecting conductor 39 is embedded in the third electrode 19 and, since this electrode I9 is almost vertically above the terminal 32, the conductor 39 extends downward through the channel 31 into the terminal 32, into which it is conductively fastened.

Succeeding triads of electrodes are similarly connected through conductors extending respectively through channels 35, 36 and 31 to corresponding terminals in succeeding columns of The ribs 33 and 34 hold the electrodes and vibrators away from the lower Wall 50 of the holder a distance sufiicient to insure that no connecting conductor can make a short circuit to any other connecting conductor or terminal except that to which it is connected. .For example, the third electrode I9, as may be seen clearly in Fig. 1, is

. held up by the rib 33 and thereby prevented from touching the conductor 28 or the terminal 29 connected thereto.

It will be noted upon inspection of Fig. 1 that the piezoelectric vibrators are arranged in the stack of electrodes and vibrators in order of That is, the thinnest vibrator 26 is at the left end of the stack, and vibrators to the right thereof are progressively thicker, the

thickest vibrator 22 being at the right. end of the stack. Although it is not necessary that the vibrators be arranged in such order, it is at present preferredto arrange them in such fashion.

Afterthe vibrators have been arranged as desired, the pin terminals 29, 30, 3|, 32, etc., are

. somewhat differently.

fastened into the lower wall If! equally spaced apart in rows and columns, and so positioned with respect to the electrodes l1, I8, ['9 20, 2| asto avoid the possibility of any terminal being touched by the conductor from an adjacent terminal in the same row. In Fig. 1, the terminals are so spaced that the terminal 29 cannot make contact with the conductor 40 of the terminal 30 in the second column. Similarly, the third terminal behind terminal 4| in the left-hand column of terminals in Fig. 1 is spaced sufiiciently from the conductor 42- of the third terminal behind terminal 43 in the column next to the leftthat there is no possibility of contact therebetween.

or more, it may be desirable to arrange them One arrangement by which the electrodes may be spaced somewhat more uniformly results by stacking the thickest vibrator 22 first, the thinnest vibrator 26 second, the next thickest vibrator 23 third, the next thinnest vibrator 25 fourth, and so on to a vibrator 44 of medium thickness at the other end of the stack. The electrodes stacked between such vibrators are more uniformly spaced and may, in certain cases, provide more convenient connections to the terminals.

By the use of the ribs 33 and 34 I am enabled to construct a holder for piezoelectric devices in which a large number of such devices and corresponding electrodes are contained in a small space and are conveniently connected to terminals arranged in rows and columns so that they are spaced apart by satisfactory distances. It is obvious that various numbers of terminals, electrodes, and piezoelectric devices, different from those illustrated, may be used without departing from the spirit of my invention. Similarly, the terminals may be arranged in different numbers of rows and columns.

It is obviously within the scope of my invention that the pins 29, 30, 3|, 32, 4|, 43 may take any suitable form for completing circuits for the electrodes ll through 2|. Such suitable forms, other than that shown, may, for example, be screws, posts, switch contacts, or the like.

While I have shown and described a particular embodiment of my invention, itwill be ob:

vious to those skilled in the art that changes and modifications may be made without departing from my invention in its broader aspects, and I, therefore, aim in the appended claims to cover all such changes and modifications as fall within the true spirit and scope of my invention.

What I claim as new and desire to secure by Letters Patent of the United States is:

1. In combination, an insulating terminal strip to which a plurality of terminals is aflixed, said terminals being spaced apart at least a predetermined distance, a plurality of conducting members spaced along said strip at less than said predetermined distance, said pluralityof terminals corresponding in number to the number of said members, said terminals being afilxed along said strip in a plurality of rows with each of said terminals positioned in proximity to a corresponding member, means lying between each adjacent pair of rows of saidterminals for maintaining said members separated from said strip whereby open channels are defined between each row of said terminals and said members, and

means passing through each respective channel for connecting each or said members to its corresponding terminal, said means being spaced from the remaining terminals, members, and connecting means associated with said channel, whereby the possibility of undesired short circuits between said connecting means, terminals, and members is minimized.

2. In combination, an elongated insulating terminal strip to which terminals maybe affixed, said terminals being spaced apart at least a predetermined distanee, a plurality of conducting plates disposed transversely tov saidstrip and spaced apart therealong at less than said predetermined distance, a plurality of rows of terminals disposed lengthwiseof said strip, the number of said terminals corresponding to the number of said plates and each of said terminals being positioned in proximity to a corresponding plate, insulating spacer means lying between each adjacent pair of rows of said terminals for maintaining said plates separated from said strip whereby open channels are defined between each row of said terminals and said plates, and a conducting member passing through each respective channel for connecting each of said plates .to its corresponding terminal, said conducting members being spaced from the remaining terminals, plates and conducting members associated with said channel, whereby the possibility of undesired short circuits between said conducting members, terminals and plates is minimized.

3. In combination, a plurality of piezoelectric yibrators and a plurality of electrodes therefor arranged alternately in a stack, a holder for said stack having a side wall and a rib on said wall against which a side of said stack rests, said stack, said Wall and said rib defining an open channel between said stack and wall on each side of said rib, a row of terminals afiixed to said wall on each side of said rib and extending into a respective channeL'and a conductor passing through a respective channel from eachof said electrodes to a corresponding terminal in proximity to said electrodes, whereby the possibility of undesirable short circuits between said electrodes, said conductors and said terminals is minimized.

4. In combination, a container having a side wall, a plurality of piezoelectric devices and a plurality of electrodes therefor stacked alternately along said wall, a terminal for each of said electrodes affixed in said wall in proximity to a corresponding electrode, said terminals being spaced apart a distance greater than the average distance between said electrodes and being disposed in a plurality of rows, conducting means connected between each of said electrodes and a corresponding terminal, and insulating spacer means between said wall and said electrodes lying between each pair of adjacent rows of said terminals for maintaining said electrodes spaced. from said wall and from said terminals and conducting means, whereby the possibility of undesired short circuits between said electrodes, said conducting means and said terminals is minimized.

CHARLES F. BALDWIN.

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