close

Вход

Забыли?

вход по аккаунту

?

Патент USA US2410268

код для вставки
0er. 29,v 1946.
w, L. CARLSON l, ‘
-
2,410,268
CRYSTAL DETECTOR
“
Filed Feb. A26, 1942
Sli/60N
.
CÁ’YSTHL 0575670@ 5
Enventor
@gwn y
Gttorneg
Y
`
I
?
2,410,268
Patented Oct. 29, Y1946
UNITED ÍsTATEs PATENT OFFICE
’ CRYSTAL DETECTOR..
Wendell L. Carlson, Haddonlield, N. J.,Íassignor
to Radio Corporation of America, a corporaf
tion of Delaware
Application‘February 26, 1942,.v Serial'No. 432,381
.12 claims. (erase-.31)
2
This invention relates to improvements in crys
tal detectors for use inthe demodulation, recti
has been `found that the desired sensitization
can be simply'achieved by rubbing or stroking
fication and “detection” of oscillations of radio
the surface to be treated with a piece of iron
frequency.
or steel.
,
There are two general types of detectors: the
crystal rectifier and the vacuum tube rectifier.
The vacuum tube rectifier has almost entirely
supplanted the crystal rectiñer in the "detection”
In carrying the invention into effect, the sili
con or other crystal S which is to be sensitized
may be ground to a flat surface or to a V-shape
or knife-like edge, V. The crystal is then pref
of oscillations within the frequency bands now
erably, but not necessarily, etched in a concenf
commonly employed in the transmission of intel 10 trated solution of sodium hydroxide and the
ligence. However, it is now appreciated by those
residue removed. Such solution may comprise
skilled in the radio‘art that there are certain
50 grams NaOH in 50 cc. of H2O at 90° C. There
signalling systems which lend themselves more
after, and in accordance with‘ the invention, a
readily to the use of a crystal rectifier than to a
deposit of a ferrous metal, oxide or alloy there
vacuum type rectifier.
15 of is applied to the said V-edge, or other con
The principal object of the present invention is
tact surface, either by one of the above men
to provide an improved crystal detector, and one
tioned conventional deposition methods or, more
highly sensitive to oscillations of ultra-high fre
simply, by rubbing or stroking the said surface
quencies. Another and specific object of the pres
with an iron wire or steel needle N (Fig. 1).
ent invention is to provide a silicon detector of 20 A very few strokes will usually suñice to greatly
enhanced sensitivity, and to provide a simple, in
increase the number of highly -sensitive contact
expensive and reliable method of sensitizing such
points on the crystal.
crystals.
The sensitized crystal may then ibe mounted
In the accompanying drawing:
in a conventional manner with its sensitized sur
Fig. 1 is a View in perspective of a crystal detec 25 face or edge V presented to a “cat whisker” or
tor element showing one form of instrument
other suitable contact C. The contact C may
which may be employedvin sensitizing said ele
comprise a conventional round wire, as shown in
ment in accordance with the method of the in
Fig. 2, or it may be cuneifo'rm, in cross section,
vention, Fig. 2 is a. view in perspective of the
as shown at C' in Fig. 3. The sharpened con
sensitized crystal detector and showing one form 30 tact portion may be made by grinding or filing
the wire of Fig. 2.
of contact therefor, and Fig. 3 shows, in cross
section, another form o-f contact for the crys
At present it is only possible to theorize as to
tal.
the reason for the improved operating charac
The foregoing and related objects are achieved
teristics of silicon crystals which have been
in accordance with the invention by the appli
treated in accordance with the invention. It is
cation of an extremely thin deposit, layer, or film
«believed that rectification of radio frequency
oscillations cannot be achieved with chemically
of a ferrous metal, oxide or alloy thereof, to the
pure silicon and that the impurities, principally
exposed or “contact” surface ofthe silicon or
equivalent crystal. This deposit, or layer, ‘or
iron, present in commercial grades of silicon are
ñlm may be submicroscopic in character, that is 40 essential to rectiñcation. Accordingly, it may be
to say, the added metal particles comprising the
that the ferrous “impurities” necessary to recti
deposit may be so fine and so sparsely distributed
fication are not evenly distributed in commercial .
grades of silicon and that the added ferrous de
as to prevent visual observation when examined
under a SOO-power light microscope, yet must be
posit of the present invention supplies the miss
in a quantity or of a character suflicient to pro 45 ing ingredient in the necessary quantity and with
duce a positive reaction when the treated sur-y `
the necessary distribution on the surface of the
crystal.
’
face is subjected to certain standard chemical
tests for the presence of ferrous materials.
What is claimed is:
The ferrous material may be deposited on the
l. Method of increasing the sensitivity of a
surface of the crystal by thermal evaporation in 50 silicon element to oscillations of radio frequency,
vacuo, by cathodic disintegration, by electrolysis,
said method comprising forming a ferrous deposit
precipitation, or by any other conventional meth
y on a surface of said silicon.
od. However, in using such methods, diñ‘ìculties
2. Method of increasing the sensitivity of a
may be experienced in achieving a. deposit of
the requisite distribution and particle size.l It
.silicon element to oscillations of radio frequency,
said method comprising forming a sub-micro
2,410,268
scopic ferrous deposit on a surface of said sili- A
con element.
3. Method of increasing the sensitivity of a
silicon element to oscillations of radio frequency,
said method comprising formingl a deposit con
stituted of discrete ferrous particles on a surface ‘
of sai-d silicon.'
f
.Y
4
said method comprising etching a surface of said
silicon piece and thereafter forming a ferrous de
posit on said etched surface.
8. Method of increasing the sensitivity of a
piece of silicon to oscillations of radio frequency,
said method comprising subjecting a surface of
Said silicon piece to the action of sodium hydrox
ide and thereafter forming a ferrous deposit on
4. Method of increasing the sensitivity of a
said surface.
piece of silicon to oscillations of radio frequency,
9. A crystal detector comprising a piece of sili
said method comprising rubbing said silicon piece 10
with a piece of ferrous material.
5. Method of increasing the sensitivity of a
con having a ferrous deposit on a surface thereof.
10. A crystal detector in accordance with claim
piece of silicon to oscillations of radio frequency
said method comprising rubbing said silicon piece
9> and wherein said deposit is sub-microscopic in
piece of silicon to oscillations of radio frequency
said method comprising rubbing said silicon piece
tially of discrete ferrous particles.
character.
11. A crystal detector in accordance with claim
15
with a piece of iron.
9 vand wherein said deposit is constituted essen
6. Method of increasing the sensitivity of a
v12. The invention as set forth in claim 9 and
wherein the surface to which said deposit is
with a piece of steel.
'
7. Method of increasing the sensitivity of a 20 applied comprises a. “knife edge.” f
‘
'
WENDELL L. CARLSON.
piece of silicon to oscillations of radio frequency,
Документ
Категория
Без категории
Просмотров
0
Размер файла
234 Кб
Теги
1/--страниц
Пожаловаться на содержимое документа