US2446254A - Blocking-layer cell - Google Patents

Description

Patented Aug. 3? 1948l I IBLGCKING-LAYER. CELL Johannes Jacobus Annen-us Ploos van Amstel. Eindhoven, Netherlands, amener to Hturtforell llatignal Bank dr Trust @n.martiord, Conn... as

rus lee r amistades swimmer so, reis, sensi no. crasse In the Netherlands :mw ywhen' 7, 1942 section i, reune new est. ausser s. ieee Patent expirer Demher 7, 1962 v i @laluna (@l; it-366) a i 2 In blocking-layer cells constituted by a earinvention provides a construction in which these rier plate, a semi-conductive electrode, a bloclndrawbacks are obviated. ing layer, a thin conductive electrode' applied According to the invention the conductive electhereto (hereinafter briefly referred to -as trede is covered with an inert intermediate layer, blocking-layer cell of the selenium type), in 5 von the other side oi which lies the metal on which a supply conductor is soldered to the'latv which or in which the supply conductor is seter, several drawbacks are encountered in rev cured. The term "inert has to be understood gard of the properties of the conductive electrode here to mean that the material does not disadat the point where the supply conductor is sol vantageously react with or act upon the metal dered to it. s 10 o the conductive electrode. The intermediate These drawbacks particularly occur when the layer may consist, for example, of iron, aluminmetal of the conductive layer easily alloys with lum or cinc. The metal of the conductive electhe soldering metal. 1n fact, since the ccetrece may in this case consist of cold, bismuth, ductive layer is very thin, this layer will entirely mmny 0r u bismuth-anthony alloy. The dissolve in the soldering .metal when itis epis letter metals have been found to be particularly plied to it so that at this place the specific prop... suitable for the manufacture of measuring cells. erties of the cell, which are a function of the AS it Solding matell use may be made 0f the metal of the conductive electrode. may change @walled e110? 103. Consisting ci tin, cadmium completely in dependence of the soldering metal. und bismuth- These drawbacks might be @imaged .by ghe According to another form ci' construction the use of a press-contact, but ln this case there is intermediate layer may consist 0f a lgcquel l again the danger that the conductive electrode MWF- AS a lacquer ethyl'ceuulcse can Very Wen might be pressed through and deteriorated, be usedme? hmdenmg the lacquer layer is which leads to instability and even to short-cin covered with u thin layer of metal, on which or @uiting of the een. r v lin which the supply conductor is secured. As is These drawbacks chiefly occur` with bloclsingwelb'known' m this case it is Vet possible to 0b' layer Geus of vsmall Size L e ,with those WMS@ v tain a conductive connection between the underconductive electrodes have a surface smaller than myeur'; hem@ me conductive electmde of the mm?, amongst others the so-called measmimgmyer ceu" and the metal laye uring cells, since with these measuring cells the '30 The surface 0f the luiluer layer will genermetal of the conductive electrode has to satisl'iotbb Mmed tg th of thefcondluctwe elic fy particular requirements which serve to eive r u m er e Ose a nger s e' a definite variation to the characteristic of the Particularly m the @me that the latter exhibits Y cell. In the case oi' larger cells, however, it gena very small Surface' this saves much trouble erally sulce's to reinforce the conductive layer 35 It has now been found with these cells that on applying the metal on which or in which the at the place vhere tih isuplyafndultor mut supply wire is secured, even when it occupies a be secured' mater a den c o t at o t e larger surface than that of the 'conductive elecconductive layer may there be used for the soltrode, the capacity substantiall does not indering. Besides, in Gase the soldered Conil@ crease. may 'be accountedyfor the tact exhibits a small surface relatively to the l that the lacquer'layer has a thickness which is surface of the whole cell. S0 that the influence great relatively to the thickness of the blocking upon the characteristic is small, if a change of layer,

the Conductive electrode WOuld Occur, provided These steps are very appropriate to be applied that this Change C1065 11011 impair the breakdown d5 to cells. the conductive electrode of which convoltage. sists of gold and has a surface smaller than Another dimculty involved with measuring cells 30 mm.

is that the electrode is frequently so small that In arder that the invention may be more clearly it is dicult t0 keep the soldering material solely understood and readily carried into eii'ect, it will within this surface. When it passes outside this be described more fully with reference to the .acsurface, then in the ilrst place the soldering compenying drawing.

metal will start to serve as an electrode, result- Figure 1 shows a blocking-layer cell in which ing in a variation of the characteristic curve, a layer of .inert metal is applied to the conductive whilst in addition the capacity oi the cell inelectrode whereas creases in a detrimental manner. The present du Figure 2 shows a blocking-4ever cell in which various layers in the correctV proportions.

the celi'is enveloped by a thin lacquer layer which has the supply conductor secured to it.

Both figures represent the cells on a greatlyenlarged scale and only diagrammaticaily.

The blocking-layer cell shownA -in Figure 1 comprises a carrier plate l which has a selenium layer 2 applied to it. This selenium layer has formed on it a genetic or a non-genetic blocking layer 3 which has applied to it a conductive electrode 4 of gold having a small surface, for example of 1 mm. in diameter. This gold electrode has applied to i't by vaporisation a thin layer of iron 5 which has secured to it a supply conductor 8 by means of a small quantity of solder 1. Since gold does not alloy with iron, the good properties of the gold electrode are thusensured, but it is evident that in view of the small size of these parts there is a great danser that the iron or the soldering material l may pass outside the boundaries of the gold electrode. These drawbacks are largely suppressed by the construction shown in Figure 2. The blocking-layer cell shown in this gure comprises, as before, a carrierV plate I. a selenium layer 2. a blocking layer 3 and a con-` ductive gold electrode l. After the blocking-layer cell has been built up so far, it is dipped in lacquer, for which purpose ethyl cellulose is appropriate. The hardened lacquer layer. which is indicated by 8, has applied to it a thin layer 9 of alloy 103 in which a supply wire 6 is secured.

The thickness of the lacquer layer is estimated to be of the order of magnitude of 10 microns. It appears that in such a lacquer layer such apertures still exist that the metal layers on each side of the lacquer layer are in contact with one another. However. rthe lacquer layer prevents the conductive electrode from being dissolved. from forming an alloy or from being changed inany other way.\\.\ l

When use is made of the invention the thickness of the conductive electrode may be chosen much thinner-'up to 10 times thinner-than it used to be.

The :ligure does not show the thickness of ltltile e blocking layer'is muchY thinner than can be shown in the figure. It is evident that due to the small thicknessof this blocking layer relatively to the thickness ofthe lacquer layer the capacity of the cell is fullydetermined by the surface of the electrode 4 and not by that of the quantity of metal 9.

What I claimis:

1 A blocking-layer cell, comprising a carrier plate. a semi-conductive electrode, a .blocking layer, a lconductive electrode applied to said blocking layer, an intermediate layer of inert material deposited on at least a portion of the exposed surface of said conduct-ive electrode, a metal contact layer applied to said intermediate layer. and a supply conductor secured to said metal contact layer.

2. A blocking-layer cell as claimed in claim 1, in which the intermediate layer consists of a metal which is chemically inert towards said conductive electrode.

-3. A blocking-layer cell as claimed in claim 1. in which the intermediate layer consists of a lacquer layer.

4. A blocking-layer cell as claimed in claim 1. in which the intermediate layer consists of ethylcellulose.

5. A blocking-layer cell as claimed in claim 1, in which the intermediate layer covers a substantially greater surface than the surface area of the `conductive electrode.

6. A blocking-layer cell as claimed in claim 1,

in which the layer of metal to which the supplyl conductor is secured also covers a surface area which is larger than the surface area of the conductive electrode, and smaller than the surface area ofthe intermediate layer.

7.l A blocking-layer cell as claimed in .claim-1, in which the conductive electrode consists of gold and has a surface smaller than 30 mm3.

JOHANNES JACOBUS ASUERUS PLOOS VAN AMSTEL.

REFERENCES CITED The following references are of record in the

Images