General Electric CRT Dept.
Tech's Filing Cabinet Miscellaneous General Electric RCA Tube Tech Semi Tech Audio Radio Components

Memos from the CRT Department that don't fall in to the other categories such as trip reports, government-funded reports, or the Talaria Project.

Fehr 440526 Formation of XRays in CRTs with High Anode Voltages - X-Rays from CRTs. Methods of measurement and ways to block X-Rays.

Fehr 1944 Brightness Requirements in TV Projection Tubes - Brightness requirements for projection TV tubes.

GE Meeting-480825 8 inch Metal Tube - Review of the development of an 8" round metal CRT. Interestingly, it was originally designed with a 15/16" neck, which would have cut the sweep power considerably. However, the eventual manifestation, the 8AP4, went with the conventional 1 1/2" neck.

Lake 1952 Investigation of Electrostatic Lenses - A proposed new electrostatic focussing lens, similar to Dumont's lens, less critical than GE's current electrostatic lens.

Ozeroff et al 1953 Proposed Improvement in Evacuation Technique for TV Tubes - A proposal to eliminate the diffusion pump when evacuating picture tubes. It is not clear that this scheme was adopted.

GE Progress Reports 1953 Basing Cement - The effect of adding silicone SR-98 to picture tube basing cement. Improved water resistance results. Unknown whether this was put into practice. GE was a major developer of silicones.

GE Electronics Lab 1954 Post-Acceleration Color Tube Vol 1, Vol 2 - 69 Mb each - A brief overview: General Electric designed a prototype color CRT in 1954 that they called their "Post-Acceleration" or P.A. tube. It had three in-line guns, a mask consisting of vertical wires, and three-color phosphors arranged in vertical stripes. The "post-acceleration" aspect was that the wire grid was at 7KV and the screen was at 20KV. Thus most of the tube was a low-energy, easy to deflect design, and the high voltage needed for brightness only happened in the last inch. The vertical wires acted as a vertical shadow mask. The positives: easy to deflect and converge, high brightness. Downsides: difficulty in putting down the phosphor stripes to match where the electrons were going to strike them (since the post-acceleration curved the deflection path), and haze and ghosting due to secondary electrons getting accelerated back to the screen. GE never made the P.A. tube commercially. In the mid-1960s, they came out with their "Porta-Color" tube that used inline guns, but a conventional color-dot shadow-mask, and no P.A. Note that the Sony Trinitron is nearly identical to the P.A. tube, but without the P.A.

The P.A. tube was planned to use a 22 inch rectangular monochrome bulb with a cylindrical face that had the faceplate cut off to allow the phosphor screening and attachment of the wire mask. Once done, the faceplate would be re-attached to the rest of the bulb by either heat or frit. One of the trouble points was the insertion of metal studs in the faceplate to attach the mask. RCA prototyped several versions of GE's P.A. color tube and had reservations (see LB-1026).

GE Progress Report 1 1954 Nickel-Titanium Matrix Cathode - An investigation of using a composite cathode to increase emission and life. The last sentence of the report: "All circumstances considered, it is felt that no definite conclusions about this type of cathode should be drawn at this stage of the investigation."

GE 195- Aging - No date or author, but probably mid-1950s. The concept and implementation of cathode aging, also called activation. This was written in the context of aging CRTs, but can also apply to regular oxide-cathode tubes.

Doggett 195- Tungsten Cathode Processing - No date, but probably mid- to late-1950s. Elaborate, detailed instructions for making some kind of sintered tungsten cathode. What tube this is for is unknown.

Devlin 1955 Emission Versus Cathode Temperature - Experiments to measure cathode emission verus temperature in a picture tube. Expected space charge limitation was not seen.

GE Progress Report 1 1955 Gettering of Gases with Titanium - Experiments on using titanium to help the gettering process in picture tubes. Quite interesting.

Zehner 1955 Diffusion of Hydrogen Through Steel - Lists the four ways hydrogen can penetrate steel: Gaseous H2, corrosion in water (rust), acid pickling, and electrolysis. Don't let your metal tubes get rusty!

GE 1955 Lacquer Studies - A set of memos on lacquer "filming". This was used as a base for the aluminum layer for aluminized picture tubes. The 27EP4 mentioned was registered in 1952 by GE. GE was one of the first companies to aluminize their tubes.

Burnette 1955 Condition of D.P.I. Buggy #17B - How to debug a production vacuum problem, circa 1955. A "buggy" is the cart that travels around holding a picture tube while it is being made.

GE 1956 PA Tube Processing Instructions - 60Mb. The various processing steps for making the 22" "P.A." color picture tube (see 1954 link above). Some processes are specific to this tube, but others are of general interest for tube manufacturing in general.

McLeland 1956 Some Temperature and Emission Characteristics of the 9QP4 vs the 21ATP4A - The 9QP4 (used in GE's "belly-telly") had low emission problems, so it was compared to the main-line 21ATP4A. The problem was traced back to cathode material formulation. Lots of curves of Ik vs If.

Sullivan & Kunz 1957 The Evolution of Picture Tube Size and Shape - How deflection angle, etc. determines the size and shape of picture tubes.

GE TV Receiver & CRT Departments 1957 An Evaluation of Color TV Display Systems - Here is a big one (302 pages, 142 Mbytes) - a 1957 analysis by GE of color TV display technology. GE was looking for something cheaper than the RCA shadow mask system, so they looked at everything available. This is large, not very organized, and is made up of various technical memos, trip reports, patent disclosures, and detailed cost estimates. There is some terminology used here that isn't obvious:

If some of the pages seem dark and fuzzy, this is because they were faded Ditto Machine copies that I had to enhance in Photoshop. If you saw the originals, you would be amazed that I was able to get anything at all from these.

Nonnekens 1957 Investigation of RF Heating - A detailed analysis of the RF induction heaters used in the picture tube "buggies" at GE.

Coppola Festa 1958 Sylvania Electrophoretic Heater Coating - The formula for Sylvania's electrophoretic heater coating, plus a copy of a Sylvania article on electrophoretic coating in general.

Perkins 1958 Effect of Immersion Lens Parameters on Beam Cutoff Voltage and Spot Size - Experiments run to determine the effect of various electron gun parameters on the beam cutoff voltage and spot size.

Coppola 1958 Cathode Temperature During Gun Seal - Experiments to determine the temperature rise of the cathode while the gun is being sealed to the CRT bulb. Since this is in an oxidizing environment (air), both the nickel supports and the barium oxide can be oxidized with bad effects on reliability. The short guns with mica in them aggravate this problem.

Coppola 1959 Operating Cathode Temperatures in 17 inch 110 degree CRTs - A study showing excessive variation in cathode temperatures in B&W CRTs. A big list of possible causes, but no concrete solutions.

Krackhardt 1960 Progress Report - Monochrome Product Engineering - Heater Design - Investigation into the design of a 12-volt CRT heater for use in a transistorized TV. Existing heater/cathode designs prove to be too fragile with the thin filament 12 volts requires.

Krackhardt 1960 Gun Design for 8 inch TV Tube - Designed for a transistorized set that never went into production, this gun has small spot size.  The tube has a "necked-down" design, where the neck is 1 1/2" at the socket, but shrinks to 3/4" at the deflection yoke. How does the deflection yoke go on?

Sullivan 1960 Picture Tube Reliability - A detailed report on efforts to increase 110 degree CRT yields and reliability. The desire for short electron guns forces reliability compromises, but nonetheless GE was able to improve quite a bit from 1957 to 1960. Note the comment that Philco's ultra-short CRTs used in the Predicta sets had awful lifetimes - less than 500 hours.

Miller 1965 Cathode Ray Tube Course - An in-house on making picture tubes. Since this is 1965, all the issues from the 1940s and '50s have been resolved. Decent details on all the steps involved. Some pages are missing.

Coffman 1967 Letter from Corning re XRays in Color Tubes - The crisis over X-Rays from color TVs is beginning to heat up. Corning has a new glass (9024) that has lead oxide, and is almost OK. Corning wants GE to limit maximum anode voltage.