Pioneers in CRT’s and Television Sir William Crookes,Sir J J Thomson, Philo Farnsworth and Vladimir Zworykin

Early CRT tubes

Television pioneer Philo Farnsworth

Pioneer in Television Vladimir Zworykin - at RCA in and around the mid 1930's as he and his team were developing the Iconoscope.

The first Iconoscope built by RCA The unit scanned 120 lines at 24 frames/second RCA, 1934

The first Iconoscope and test pattern RCA, 1934

Early TV Picture (RCA) from first Iconoscope-1934

RCA Image Orthicon(1948) and Hitachi single tube colour camera

8 mm colour camera tube

The Iconoscope

The Iconoscope The Iconoscope was developed by  Vladimir Zworykin, and used in electronic TV broadcasting from 1939 until it was replaced by more advanced tubes. Inside the Iconoscope, the image is projected on a mosaic (M) consisting of granules of photo-emissive material. Emission of photo-electrons from each granule in proportion to the amount of light  results in a charge image being formed on the mosaic. Each granule, together with the conductive plate behind the mosaic, forms a small capacitor, all of these having a common plate. The capacitors are discharged in succession when the mosaic is scanned by a high velocity electron beam (E) from the electron gun, and the resulting changes in potential at the metal plate constitute the picture signal. The "sensitivity" is 75 000 lux.The picture shows RCA 1850A. The price in 1948 was USD 540,- An unusual application with an Iconoscope can be found here at Tubepedia

Image-Iconoscope This has a kind of electron multipier to improve the sensitivity which has been increased to 1000 lux.

P.E.S-Photikon Here, a bias light further improves the sensitivity to 300-500 lux

Orthicon The electron beam has a relatively low speed and magnetic focusing is needed to keep the beam narrow. The anode is placed in the same end as the electron gun and the return beam is modulated according to the light input. Sensitivity 3000 lux

Image Orthicon

Image Orthicon The Image Orthicon was a big step forward. It includes a five stage electron multiplier. The picture shows the 3" RCA 5820. Sensitivity 200 lux Dimensions: 75 mm diam,  385 mm length, weight 400 grams.Vidicon  Sensitivity 500 lux Picture shows:   Philips XQ1270 3/4", diam 19 mm, length 100 mm, weight 23 g. Philips XQ1030 1", diam 27 mm, length 140 mm, weight 50 g. Vidicon with magnetic deflection unit. The Spectraplex vidicon type 4445 was RCA's attempt to create a single tube color TV camera. They made one camera model with this tube. Further history is unknown. The size is : diam: 25 mm, length 140 mm. Weight: 50 grams. Plumbicon Philips improvement of the vidicon. The picture shows XQ1074 which were available in three versions, R, G and B for colour TV camera. And for comparison only:   A small solid state color TV camera "Mintron" with C-mount for lens. Dimensions: 110 x 55 x 50 mm. Weight: 360 grams excl. lens, 470 grams incl. F1,4/16mm lens. Power needed: 12 VDC, 100mA. Sensitivity:  4 lux.  Output signal: 1,0 Vpp composite video. Can be externally synchronized. An ultra miniature solid state pin hole color TV camera with 1/4" CCD sensor. Built in 4,3 mm lens / f2,8. Dimensions: 19 x 33 x 29 mm. Weight:  50 grams. Power needed: 5 VDC  Sensitivity: 2 lux, 330 lines resolution, 290 000 pixels. B/W version of camera has 0,1 lux sensitivity !!! Output signal: 1,0 Vpp composite video. Made by COP Security Taiwan. (Yes, it is the same matchbox) A micro sized monochrome camera for surveillance use, type CAMZWCMM. It measures 15 x 15 x 17 mm. Weight: 5 grams, Power needed 12 VDC. Sensitivity 0,5 lux. Made somewhere in Taiwan. (Still the same matchbox) NEW 2002-01-27 HOME © 2001, Åke Holm, Sweden

TheVidicon TVcamera

Plumbicon Philips improvement of the vidicon. The picture shows XQ1074 which were available in three versions, R, G and B for colour TV camera.

Solid-state CCD cameras A small solid state color TV camera "Mintron" with C-mount for lens. Dimensions: 110 x 55 x 50 mm. Weight: 360 grams excl. lens, 470 grams incl. F1,4/16mm lens. Power needed: 12 VDC, 100mA. Sensitivity:  4 lux.  Output signal: 1,0 Vpp composite video. Can be externally synchronized. A micro sized monochrome camera for surveillance use, type CAMZWCMM. It measures 15 x 15 x 17 mm. Weight: 5 grams, Power needed 12 VDC. Sensitivity 0,5 lux. Made somewhere in Taiwan. (Still the same matchbox)

Crookes Maltese Cross Tube

The Maltese Cross tube is one of the most famous Crookes tubes The Maltese Cross tube is one of the most famous Crookes tubes. The tube demonstrates that electrons go in a straight line and don't go through metal.  The cross can actually lay down and stand up (mechanical).  When the cross lies down, the glass face of the tube emits a green glow when the electrons strike the glass wall, when it's right up you will see the shadow of the cross.

The Cathode Ray Deflecting tube The Cathode Ray Deflecting tube demonstrates  the influence of a magnetic field to the electron beam. The beam will bent away from the center when a magnet is held near the tube.

Crookes Mineral Tube

Crookes Flower Tube

Crookes Railway Tube

The Goldstein Canal Ray tube. This tube demonstrates that besides the cathode rays there  is another stream that travels in the opposite direction as the  electron flow. Discovered in 1886 by Eugen Goldstein who  called it "canal rays". In fact these are positively charged  protons, producing a reddish light in the upper part of the tube  while in the lower part the usual green emission of electrons    can be seen when they hit the glass wall. The curious thing is  that the electrons in the lower part of the tube can be deflected  by a magnet but the canal rays are not.  Goldstein could not explain this phenomenon, it took 12 years  before Goldstein's paper was published. Goldstein Canal Ray Tube The perforated cathode. Canal Rays This tube demonstrates that besides the cathode rays there  is another stream that travels in the opposite direction as the  electron flow. Discovered in 1886 by Eugen Goldstein who  called it "canal rays". In fact these are positively charged  protons, producing a reddish light in the upper part of the tube  while in the lower part the usual green emission of electrons    can be seen when they hit the glass wall. The curious thing is  that the electrons in the lower part of the tube can be deflected  by a magnet but the canal rays are not.  Goldstein could not explain this phenomenon, it took 12 years  before Goldstein's paper was published. Goldstein Canal Ray Tube The perforated cathode. Canal Rays

Sir J J Thomson Excuse me... how can you discover a particle so small that nobody has ever seen one?

Cathode Ray Tube J J Thomson at office J J Thomson’s Cathode ray Tube J J Thompson at Office J J Thompson’s Cathode ray Tube

Cathode-Ray Demonstration Tube

Geissler Tubes

Colour Science

Vectorscope Display & Graticule

References-Internet Resources Wikipedia website Ake’s CRT Tube data site Sparkmuseum site Brittanica Online Texas A&M Univ.- Color Science web-site Monochrome and Colour Television- R R Gulati http://members.tripod.com/~FrameMaster/ Zworykin images credit to Steve Restelli,Restelli Corporation,USA. Compiled by S R Norman,Faculty SSNCE,Chennai (for educational use only)