US2630512A

US2630512A - Semiconductor unit

Info

Publication number: US2630512A
Application number: US767309A
Authority: US
Inventors: Rahbek Knud
Original assignee: Individual
Current assignee: Individual
Priority date: 1946-02-27
Filing date: 1947-08-07
Publication date: 1953-03-03
Anticipated expiration: 1970-03-03
Also published as: GB631804A

Description

106- 4 CROSS REFERENCE EXAMINER March 3, 1953 K. RAHBEK 2,630,512

SEMICONDUCTOR UNIT Filed Aug. 7, 1947 SEMICONDUCTOR UNIT Knud Rahbek, Frederiksberg, Denmark Application August 7, 1947, Serial No. 767,309 In Denmark February 27, I946 This invention relates to semi-conductor units for the utilisation of electro-adhesion.

In the production of semi-conductor units for this purpose, it'has appeared that natural semiconductors, such as agate, slate, soapstone and others, suffer from the disadvantage that they are laminated and therefore do not give a perfectly uniform effect independent of their orientation. If, thus, in the semi-conductor unit a cylinder produced, for instance, of agate is being used and rotated in relation to a band made of an electrical conductor which is held pressed against its surface, the tension caused in the longitudinal direction of the band by electroadhesion'vary with the immediate position of the agate in relation to the band, which may cause considerable trouble in the use of the unit.

The object of the present invention is to indicate a method"'for the production of artificial semi-conductors which are homogenous and therefore do" not suffer from the said defect. Thisis attained by using a unit consisting of a semi-conducting body composed of semi-conducting powdery particles bound together by an electrically conducting binding agent, a metallic electrical conductor contacting the surface of said semi-conducting body, means for moving said body and said conductor relatively to each other along their contacting surfaces and means for applying an electrical potentiaL. difference between the contacting surfaces of said body and said conductor. y

Moulded pieces produced in this manner have proved to possess excellent semi-conductor properties, and they may easily be given such mechanical properties as to make them suitable for use in the semi-conductor units in question. The production of artificial semi-conductors entails the further advantage, that the semi-conductor may easily be given the form suitable for the purpose for which it is to be used, which isotherwise rather difficult, when for instance natural semi-conductors are used, which like agat'epossess very great hardness and therefore can be worked only with difliculty.

Onthe drawing two examples of semi-conducting units in accordance with the invention are shown in side elevation in Figs. 1 and 2 re-, spectively.

The unit shown in Fig. 1 consists of a rotatable metallic drum I, which by means not shown can be rotated in direction of the arrow 2. Upon the cylindrical surface of the drum I a cylindrical layer -3 is fastened, which according to Section 1, Public Law 690, August 8, 1948 Patent expires February 27, 1966 10 Claims. (01. 201-66) means of springs 5 and 6 attached at oneoim their ends to the ends of the band 4 and fixed at the other of their ends to holding means 1 and 8 in the apparatus, in which the unit is used. These means are only shown quite diagrammatically onthe drawing. The spring 6 attached to that end of the band 4 against which the layer 3 is rotating is a weak spring, whereas the other spring 5 is more powerful. Between the metallic drum 1 and the metallicband 4 an electrical potential E is impressed as indicated on the drawing.

Thelunit shown in Fig. 2 consists also of a metallic drum I, which can. be rotated in direction of the arrow 2. Against the cylindrical surface of this drum a semi-conducting band consisting of a layer 9 of powdery particles bound together by an electrically conducting binding agent on a reinforcing wire netting I0 is pressed. Also this band is by means of springs 5 and 6 attached to its ends connected to holding means I and 8 in the apparatus, in which the unit is used and an electrical potential E is impressed between the metallic drum I and the band 9 as shown.

When the potential E is varied during the rota'tion of the drum I, the force exerted by the spring 5 on the holding means I and the position of the band in relation to the holding means in both examples will in known manner vary in accordance with the variations of the potential.

By a suitable choice of the substances used in the production, semi-conductors possessing different properties, corresponding to the various uses to which they are to be put, may be produced. It has proved that the powder used may be produced by pulverising natural semi-conductors, such as agate, slate, Solenhofen stone or %a gs tgn q, but also natural powders or im'neral pow ersin commercial use may be used, as for instance talc or flint powder.- As binding agent coagulent mineral substances, as for instance, water glass, may be used. It may be pointed out that flint powder stirred up in waterglass will make an artificial semi-conductor which is as hard as natural agate, and which can be out only with a diamond. Such an artificial semiconductor possesses eminent properties as such. Likewise talc cast in water glass will make an excellent semi-conductor. Both possess the advantage of coagulating slowly, so that the semithe inventign consists of powdery particles bound 56 wnductors y j lly be formed, for instance in hands when they are cast on wire netting. A semi-conductor produced of talc is to a certain extent self-lubricating, so that it will be especially suitable for units destined to be used in loudspeakers.

'- As bindin t may also be used coa ulent, organic su stances", especially substances containing cellulose or 'lastic substances which in connection with even a hard powder may make a relatively soft semi-conductor.

As already mentioned in the foregoing and shown on Fig. 2 on the drawing the mixture of powder and binding agent may prior to coagulation be placed on reinforcing wires, preferably one or more wire nettings, whereby it will be possible to cast the semi-conductor in many different forms, which may only with difliculty be obtained when natural semi-conductors are used.

The mass may also as shown in Fig. 1 be cast as a surface layer on a base formed in accordance with the purpose for which the semi-conductor is to be used. Such a base may preferably consist of metal, the surface of which has beforehand been made rough or rifled, so that the mass will hold securely onto the surface.

I claim:

1. A semi-conductor unit consisting of a semiconducting body composed of semi-conducting powdery particles bound together by an electrically conducting binding agent, a metallic electrical conductor contacting the surface of said semi-conducting body. means for moving said body and said conductor relatively to each other along their contacting surfaces and means for applying an electrical potential-diiference between the contacting surfaces of said body and said conductor.

2. A semi-conductor unit as stated in claim 1 wherein the semi-conducting body is built up of pulverized agate.

3. A semi-conductor unit as stated in claim 1 wherein the semi-conducting body is built up of pulverized slate.

4. A semi-conductor unit as stated in claim 1 wherein the semi-conducting body is built up of pulverized Solenhofer stone.

5. A semi-conductor unit as stated in claim 1 wherein the semi-conducting body is built up of pulverized soapstone.

6. A semi-conductor unit as stated in claim 1 wherein the semi-conducting body is built up of pulverized tale.

7. A semi-conductor unit as stated in claim 1 wherein the semi-conducting body is built up of pulverized flint.

8. A semi-conductor unit as stated in claim 1 wherein the semi-conducting body is built up by the said powdery particles being bound together by water glass.

9. A semi-conductor unit as stated in claim 1 wherein the said powdery particles are bound together by the said binding agent on a reinforcement base.

10. A semi-conductor unit as stated in claim 1 REFERENCES CITED The following references are of record in the file of this patent;

UNITED STATES PATENTS Number Name Date 129,096 Brown July 16, 1872 956,870 Wright et al May 13, 1910 1,393,346 Cook Oct. 11, 1921 1,533,757 Rahbek et al. Apr. 14, 1925 1,638,849 Haverstick Aug. 16, 1927 1,638,888 Slepian Aug. 16, 1927 1,883,675 Frank et al Oct. 18, 1932 1,973,732 Snell Sept. 18, 1934 1,983,498 Lux Dec. 4, 1934 2,278,072 Gould et al Mar. 31, 1942 FOREIGN PATENTS Number Country Date 503,218 Great Britain June 30, 1937 I I y