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April 6,` 1937.
R. BECHMANN 5T A1.
2,076,060
PIEZOELEGTRIC CRYSTAL HOLDER
Filed oct. 12', 19:55'
WlLHELM SCHNEIDER
ATTORNEY.
2,076,060
Patented Apr. 6, 1937
~ PATENT »OFFICE
UNITED STATES2,076,060
PIEZOELECTRIC »Y
rCRYSTAL HOLDER
Rudolf Bechmann and Wilhelm Schneider, Berlin,
für
Germany,
Drahtlose
assignors
Telegraphie
to Telefunken
m. b. H., Gesellschaft
Berlin, Ger-- ‘
many, a corporation of Germanyk
Application October, 12, 1935, Serial No. 44,674
In Germany November 6, 1934
9 Claims.
(Cl. 17 1-327)
pheric agencies, for these are liable to cause ir
This invention relates to a new and novel hold-v
er for a piezo-electric crystal oscillator.
This application is a continuation in part of
regularities of the surface and partial changes
in the interelectrode distance, itis recommenda
application Serial No. 738,454, iiled‘r August 4,` ble to use for metallization the surface with a
kind of metal, preferably chromium, that will bc
stable both in reference to atmospheric and hu
5 1934.
In the above-mentioned patent application, ay
holder or setting means for oscillators of the
midity actions,
.
I
One exemplified embodiment of the> invention
essential feature of which is that the crystal andA is illustrated in the drawing in which Fig. 1 shows
piezo-electric crystal type has been disclosed, the
`a plan view of the crystal holder, a portion 0f
l0 the electrodes are embedded inside a casing con
sistingA of ceramic material.
Which is broken away to showk the inner construc
The present inven- f
tion discloses a further improvement of the said ~ .
tion; Fig. 2 is a cross section of‘Fig. l; Fig. 3 is
crystal holder which is predicated upon the :fol-> , an enlarged’detailed portion of Fig. 2. The ring
, like casing made kof ceramic material l, sur
lowing considerations.` o
15
20
'The temperature coefficient of a vcrystal device rounds the oscillator crystal 2 which is planar or
consists of the temperature coefficient of the crys~-; laminar in form, and which is secured by cen
tal itself, and the temperature coeiiìcient ofthe tering ring 3. SupportingA of the crystal is ef
crystal holder. >A number .of suggestions are ' fected in this manner that the crystal plate has
known from the prior art with a view to minimiz `a peripheral groove or slot into which engage
ing the temperature coefficient of the crystal it v yieldingly or elastically the peaks or supporting 20
studs 3’ inserted in the centering ring 3. The
selfA by choosing a suitable cut. .Hence still fur
ther decrease of the temperature> coeflicient of'. latter is clamped fast on both sides by insulating
the entire device is obtainable only by a reduction ringsA made of ceramic material 4, and the elec
trode holder means »5; ' These latter, as shown in
of the temperature coeflicient of the crystal hold
er. yEspecially in the case of holders of such f the drawing, are secured onthe casing I by means
crystal oscillators as are called upon to insure of a screw threadedjoint. The electrodes desig-`
an extremely high-frequency stability or con
stancy, for instance, when employed as crystal
monitors in connection with transmitters or as
quartz “clocks”, it is of essential importance that
the temperature coeflicient be kept small.
As a general rule, the electrodes are at an ex
tremely small distance from the surfaces of the
crystal; but this interval of space andl its sta
bility or preservation is essential from the View
point of the oscillatory state and the frequency
stability of the crystal. As a result, even changes
in the distance should be avoided which, per se,
would be small, but which would exercise a high
40 percentage influence. In fact, it has been for
this reason that the earlier filed patent applica
tion contains the instruction that the electrodes
should be confined inside a casing consisting of
ceramic material, the underlying idea being to
utilize the small temperature coeñicient of cera
mics rather than the higher temperature coeffi
cient of metal.
Now, according to this invention, not only for
the casing, but also for a portion of the principal
mass of the electrodes, ceramic material is em
ployed, such necessary metallic surface portions
of the electrodes as are placed opposite the crys
tal being, if desired, metallized for the purpose of
obtaining electric conductivity. In order to pre
55 clude soiling of the electrode surfaces by atmos
, nated Iby 6 are of ceramic material and they are
metallized upon the working or` active surfaces 6’
whichare located opposite `the crystal» To in
sure adjustment of the distance between the elec~
trode surfaces and the crystal, the electrode
bodies 6 are embedded in metal rings or caps 1
which have a fine-pitched male screw thread 1',
by means of which they are adjustable in the
bushing-like electrode holders 5 which have fe~ 35
male thread. In order to ñx the distance once
adjusted, there is provided the screw-threaded
rings 8 arranged on both sides.
The ceramic
casing caps or cover pieces l0 on both sides are
united with the casing l by means of screws l2. ,.
The preferable plan is to make the casing fasten«
ing screws I2, as shown, in such a Way that one
and the same bolt serves to secure, on the one
hand, the electrode holder 5, and, on the other
hand, the casing cap I0.
For the purpose of establishing conductive con
nection with the electrode metallized surfaces,
there is provided a metallic spindle 9 which is
fixed within the electrode body 6 and in conduc
tive connection with the electrode rnetallized sur"
faces, said spindle 9 being maintained in elec
trical contact with a lead-in supported in cap I0.
In order to insure safe contact-making, lead Il
is made yielding such that its spindle stud i I’ is
pressed against the end surface of conductor B
2.
2,076,060
by virtue of spring I3 applying pressure to mem
ber 9.
Having thus described our invention, what we
claim is:
l. A piezo-electric Crystal holder comprising
crystal within said casing, a ring-like supporting
member for supporting and surrounding said
crystal, securing means whereby said supporting
an insulating casing, a crystal within said casing,
a supporting member for said crystal, two insulat
ing members located at each side of said crystal,
said insulating members having their Surfaces
said crystal, said insulating members having
their surfaces that face said crystal coated with
10 that face said crystal lcoated with metal to act as
an electrode for said crystal.
2. A piezo-electric crystal holder comprising
an insulating casing of ceramic material, a crys
tal within said casing, a supporting member for
15 said crystal, two insulating members of ceramic
material located at each side of said crystal, said
insulating members having their surfaces that
face said crystal coated with metal to act as an
electrode for said crystal.
20
3. A piezo-electric crystal holder comprising an
insulating casing, a crystal within said casing,
a supporting member for said crystal, two adjust
metal, each of said metal surfaces acting as an
electrode for said crystal.
7. A piezo-electric crystal holder comprising an
insulating casing having removable end caps, a
crystal within said casing, a ring-like supporting
member for supporting and surrounding said crys
tal, securing means whereby said supporting
member is secured within said casing, two in
sulating members located each side of said crystal,
said insulating members having their surfaces
that face said crystal coated with metal, each of
said metal surfaces acting as an electrode for
said crystal, and means passing through the end
of said Casing for connecting said metallic sur
to act as an electrode for said crystal, and
faces outside of said casing.
8. A piezo-electric crystal holder comprising an
insulating casing having removable end caps, a
crystal within said casing, a ring-like supporting 25
member for supporting and surrounding said
means for connecting said metal surfaces outside
of said casing.
4. A piezo-electric crystal holder comprising
a ring-like insulating casing having removable
member is secured within said casing, two insu
lating members located each side of said crystal,
said insulating members having their surfaces 30
end caps, a crystal within said casing, a support
ing member for said Crystal, two insulating mem
Said metal surfaces acting as an electrode for
able insulating members located at each side of
said crystal, said insulating members having their
25 surfaces that face said crystal coated with metal
30
member is secured within said casing, two ad
justable insulating members located each side of
bers located at each side of said crystal, said
insulating members having their surfaces that
35 face said crystal coated with metal to act as an
electrode for said crystal.
5. A piezo-electric crystal holder comprising
an insulating casing having removable end caps,
a crystal within said casing, a ring-like support
40 ing member for supporting and surrounding said
crystal, securing means whereby said supporting
member is secured within said casing, two insu
lating members located each side of said crystal,
said insulating members having their surfaces
45 that face said crystal coated with metal, each of
said metal surfaces acting as an electrode for said
crystal.
6. A piezo-electric crystal holder comprising an
insulating 'casing having removable end caps, a
crystal, securing means whereby said supporting
that face said crystal coated with metal, each of
said crystal, and means passing through the cen
tral portion of said insulating members and
through the end of said casing for connecting said
metal surfaces outside of said casing.
9. A piezo-electric crystal holder comprising an
insulating casing having removable end caps, a
crystal within said casing, a supporting member
surrounding said crystal, securing means whereby
said supporting member is secured within said
casing, two insulating members having threaded
bushings secured to each end thereof for adjust
ing said members with respect to said crystal,
said insulating members having their surfaces
that face said crystal coated with a metal to act
as an electrode for said crystal.
RUDOLF BECHMANN.
WILHELM SCHNEIDER.