Patent GB-355795-A (GB)
Title: Improvements in or relating to apparatus for the transmission and/or reproduction of views, scenes, and other objects by electrical means
IPC: H04N3/04
Filed: 1930-05-24
Abstract: 355,795. Television. MALONEY, P. E., 9, Main Street, Dundrum, Co. Dublin. May 24, 1930, No. 16063. [Class 40 (iii).] Relates to scanning devices and has for its object to scan more finely. In one form of the invention, a disc A, Fig. 1, has apertures 3 arranged on a spiral of several convolutions. I n order to prevent more than one aperture 3 scanning the object O, a disc B having a spiral slit is arranged to rotate with the disc A, the spiral slit having a width greater than the width of an aperture 3. The disc B rotates at the speed of the normal scanning device while the disc A rotates faster according to the number of convolutions of the apertured spiral. If more than one cell is used and more than one area of the object is scanned simultaneously, the disc B has a spiral of more than one convolution, or several equal spirals. The disc A may be replaced by two discs, one having radial slits and the other having a spiral slit of several convolutions, the two discs having any desired relative speed, Figs. 13 and 14 (not shown). The spiral slot in the disc B is formed by rotating a suitable spiral about the centre of the disc in both directions and it has a length preferably greater than one convolution. The width of the slot is uniform, but tapers in the overlapping portion. The apertures 3 are preferably arranged on radial lines, and the last aperture of the spiral is not situated at the end of the spiral curve. The spirals preferably have their poles at the centre of the disc. If synchronism is attained by use of a phonic wheel, the number of teeth of the wheel is made equal to the number of radii upon which apertures are situated. The disc B may be replaced by two discs, one having spiral slots, each of one convolution, equal in number to the convolutions of the spiral in disc A, and the other having an equal number of spiral slots of onequarter convolution, these discs rotating with speeds such as to allow only one aperture 3 to scan the object at a time. For colour transmission, the two discs replacing disc B are used ; one has three spirals of one-quarter revolution, each fitted with a colour fitter and rotates at three times the speed of the usual scanning disc ; the other has one spiral slot like disc B and rotates three times faster. Stereoscopic effects are obtained by scanning an object consisting of two views from different points in juxtaposition, the received image being viewed through suitable apparatus. For duplex working, one-half of the field scanned is transmitted, while the other half is used as a receiver screen ; thus half the apertures act as analysing elements and the other half as recomposing elements. The apertures may be fitted with lenses or other optical devices, cells or light sources. In these two latter instances, the disc is fitted with distributers so that each cell or light source is connected in circuit in turn, Figs. 16 and 17 (not shown). The discs may be replaced by cylinders or hollow conical bodies, and the object may be scanned with light outside the visible range. The scanning devices may be modified for use with kinema films by leaving a portion of the disc without apertures so that scanning ceases while the picture is changing. Specification 302,228, [Class 40 (iii), Telegraphs, Electric], as open to inspection under Sect. 91 of the Acts is referred to.