This lecture was first presented the 20th of May 2014 at Philips Research in the series Centennial Lectures celebrating the 100th anniversary of Philips Research. The Dutch version was presented the 25th of May 2014 at the Philips Museum and original Philips factory at the Emmasingel, Eindhoven. The lecture loosely follows the development of vacuum electronics at Philips (Research) during the interwar period. .

Klik hier voor de Nederlandse versie

Ladies and gentlemen,

It is the evening of the 9th of May 1940. Despite the fact that it is a nice and cool spring evening, the atmosphere in Eindhoven is tense and unreal. Germany has been building up a large armed force near the border, and people realize that it is only a matter of time before they will invade their country. Nevertheless, the radio tube factory of Philips in Eindhoven, known as the “White Lady,” is the scene of unusual activity. On orders of the director responsible for radio tube manufacturing and development – Theo Tromp - the factory has been working at top capacity to produce an enormous amount of the newest type of radio tubes for an unknown customer, with an unknown application. Duplicates of special machines to make these tubes have been hurriedly put together, and everything is now being loaded onto a truck which later that evening will leave for the Dutch coast, with England as destination.

Nobody could have suspected that that same night, at 5:30 in the morning, Germany would indeed start the invasion of Holland. Philips has prepared itself thoroughly for the forthcoming war.

A detailed evacuation plan has been worked out and is set into motion. That day, an enormous caravan of trucks packed with vital machinery, equipment, and staff leaves Eindhoven heading for the North of Holland. The largest part of the convoy gets stuck at the bridges over the large rivers, which are already in the hands of German paratroopers.

However, by that time, as by miracle, the truck with its mysterious cargo has already reached the harbor of Vlissingen. Despite the fact that all ferry transport between Holland en England had been suspended since the English and the French had declared war on Germany in September 1939, the truck is expected, and quickly loaded onto one of the ferries. In the meantime the news of the invasion has reached the coast and in the early morning all three ferries of the “Zeeland” Steamer Company disembark with destination Harwich. Once on sea the ships they are attacked by German fighter planes and one of the ships - “the Princess Juliana” - is damaged so heavily that it has to return to Holland. However, the “Koningin Emma” and the “Princes Beatrix” – one of them carrying our truck with its special cargo - safely reach England.

The period between the Wars was for Philips a period of tremendous growth and diversification. Before the First World War, Philips had been producing only light bulbs, but by the time the Second World War started, it had become a leading manufacturer of electronic components and systems, especially radios. In this presentation we will loosely follow the developments with respect to vacuum electronics during the interwar period, and in particular trace back the events which led up to the dramatic happenings with which we started this presentation.

To do that, we have to go back in time to 1914, the year the First World War started. Philips is now the largest private employer in Holland, and it is about to celebrate its 25th anniversary.

In the years preceding the war, Philips had gone through a small crisis because they were taken completely by surprise by two innovations of General Electric which directly threatened their successful business: the ductile tungsten filament and the gas filled light bulb.

Anton Philips, who clearly never followed any courses in business ethics, quickly sails to the US, and manages to buy the required equipment directly from the suppliers of GE. Back home he even hires technicians from GE who are working in Germany, to come to Eindhoven during the weekends to teach the engineers in Eindhoven the new technology!

The activities do not remain unnoticed and even the Meijeresche Courant reports “how strangers from who know where have been involved in mysterious experiments!”

Although the danger is averted, the Philips brothers realize that the innovations of GE are the result of fundamental research. To safeguard the future of the firm, they decide to embark on their own research program, and an advertisement is placed in the Nieuwe Rotterdamsche Courant.

In 1914 Giles Holst is hired to setup a physics lab, and a year later Ekko Oosterhuis is hired to strengthen the team.

The first lab is situated on the fourth floor of the building that preceded the white lady on the Emmasingel, and which was nick named the Sing Sing after the famous prison in New York. The first years there is not much time for exploratory research, since both Holst as well as Oosterhuis often have to help with problems in production.

One person who is particularly skillful at that is Cornelius Bol. Cornelius Bol is - although not that well known - a legend within Philips Research, and perhaps the first in the long line of eccentrics that have been so characteristics for this lab. Cornelius Bol had been an apprentice carpenter and blacksmith in his father’s workshop. After his father died, he was taken as a pupil in the famous lab of the Nobel Prize winner Kamerling Onnes’ in Leiden, where he received training in glass blowing, electrical engineering and instrument making. But Holland is too small for Bol, on his eighteenth he leaves for the US where he finds employment as a farmer, and later as a cinema manager in Montana. Finally he settles down in Princeton where he does a bachelor in Physics. Bol was in the habit of returning to Holland for vacations and when he went home in 1916 he found he had been listed as a military deserter and he is forbidden to return back to the US.

In search for a job he meets Holst who is impressed by his combination of practical skills, and his academic way of thinking, and so, in 1916, Bol became the fifth person to be employed at Philips Research. Bol’s obsession with technology, and the substantial improvements he brings to the production processes quickly impress even Gerard Philips, despite the fact that he is often reprimanded for his unorthodox conduct. In the autumn of 1916 Bol is lifted from his bed by the police, and imprisonment for desertion. In prison Bol asks for solitary confinement, paper, and pencil, and during his two weeks imprisonment works out detailed planes for the first fully automatic light-bulb manufacturing carousels. His work not only impresses the prison director, but also Gerard and Anton. After his release he is called to their office, and receives a gratification of a 1000 guilders, with the urgent advice not to talk about it to the other staff. With the money Bol is able to marry his wife Corry Barentsen.

While all this is happening the terrors of the First World Ware rage around neutral Holland. And so it happens that on a quiet summer evening in August 1917 a German seaplane is forced to make an emergency landing in de Waddenzee, in Dutch territorial waters. The plane is salvaged and on inspection the Dutch military discover something that surprises them: a radio receiver with radio tubes! It has to be understood that in 1917 the triode amplifier tube was only a few years old, and one of the most “high-tech” things around. The war had given the development of radio an impulse, but in neutral Holland the developments had lagged behind. It is therefore not surprising that the military inspect this new gadget with unusual interest. Understanding the potential of it for modern warfare, captain “de Blauw” is commissioned to construct a number of radio sets. For the necessary radio tubes captain “de Blauw” obviously turns to Philips, and he makes an appointment with Giles Holst. As it happens, this is the start of a remarkable chain of events.

Holst politely receives captain “de Blauw” and listens to his story and request for help in the fabrication of radio tube. Undoubtedly, the physicist in Holst must have been fascinated by these new gadgets. However, Holst also knew that Gerard Philips considered radio as a play thing for the military, and something with little practical and commercial value! Holst finds it difficult to do something that might upset his boss only three years after being hired, and although he is tempted, he reluctantly turns down captain de Blauw’s request for help. Disappointed, captain “de Blauw” turns to one of the other light-bulb manufacturers in Holland. They are quite willing to help, and so it happens that the first radio tubes in Holland were not made by Philips, but by “de Fijnmetaaldraad en lampenfabriek” in Utrecht.

At the time of the First World War there was nothing that can be compared with radio as it is today. During the war listing to radio had been forbidden, but after the war radio amateurism gained enormously in popularity. The technological advancements during the war now became available to private individuals. But what to listen to? Most transmissions were in Morse code originating from post offices, news agencies and of course the odd spy. Transmission of speech, let alone music was practically unheard of.

The Dutch radio pioneer and visionary “Hanso Hendricus Schotanus à Steringa Idzerda”- a difficult name to pronounce even to Dutch standards - had something different in mind. Idzerda owns a small company - the “Nederlandsche Radio-Industrie” - and it is his dream to build and sell radio receivers to ordinary civilians.

Since there is basically nothing to listen to, he provides the buyers of his radio sets with interesting radio programs consisting of news and music transmitted from the roof of his workshop in The Hague. On the 5th of November 1919, Idzerda places an advertisement in the newspapers announcing a “Soirée-Musicale.” The event is internationally recognized as the birth of public broadcasting.

For his radios Idzerda needs a steady supply of radio tubes, so naturally he turns to the only manufacturer of radio tubes in Holland - the “FijnMetaaldraad en lampenfabriek” in Utrecht. To their disappointment they are not able to supply him the tubes since they have signed a “contract of secrecy” with the ministry of war, and so Idzerda turns his hope to Philips again. One way or the other he is able to convince Gerard Philips himself of the economic significance of his enterprise, because this time Gerard orders Holst and his staff to fabricate the tubes according to Idzerda’s specifications. The tubes are advertised under the name “IDEEZET-lamps,” and in an advertisement in “Radio Nieuws” of January 1919, Idzerda proudly announces that already 1450 tubes have been sold. Just imagine what would have happened if Holst had supplied the tubes to the military! Most likely this whole campus would not have existed then.

In the following years, the fabrication of receiver tubes remains a relatively insignificant activity. This is however not the case for X-ray and transmission tubes. There, a stroke of luck places Philips in an ideal position. In the early years of 1920, Holst visits one of the glass-blowing factories where light-bulbs are being made. He notices that some of the glass-blowers have more difficulty in removing the glass bulb from their blow-pipe than others. He finds this intriguing, and decides to investigate the cause. He discovers that when the blow-pipes are made from a particular chromium-iron alloy, they have an almost perfect adhesion and thermal match to the glass. The story goes that Holst after finding the cause immediately rushed to the patent department and got the discovery filed.

The patent indeed proved of immense value to Philips. It allowed them to enter the medical market with a safe and robust X-ray tube, and it allowed the fabrication of powerful water cooled transmission tubes.

Finally in 1923 the idea of public radio broadcasts really sets off, and the demand for radio tubes explodes. Tube manufacturers are hardly able to supply the demand and also Philips quickly changes gears. After the fabrication of light-bulbs was moved to a location just outside the center of Eindhoven, the huge plant on “de Emmasingel” became available for the production of radio tubes. Whereas in 1921 only 320 radio tubes were fabricated in total, in 1923 the production had increased to a 1000 tubes a day!

In 1922 Holst hires the Dutch Scientist Balthasar van der Pol to head the research and development of radio tubes. Van der Pol who had worked under Thomson and Fleming in England was a brilliant scientist who already in 1917 in “Wireless World” had featured in an article “Personalities of the Wireless World.” Van der Pol’s first job was to work on one of the most critical aspects of radio tubes, the cathode.

Van de Pol and his staff develop a process to coat the filaments of radio tubes with a special oxide which makes it possible to operate them at a much lower power consumption. Philips successfully introduces these tubes in 1924, and even today these tubes are still known by the iconic brand name “Miniwatt”. At that moment already 9 out of the 16 researchers at Philips are working on radio tubes.

In the period before the war the national markets in Europe were heavily protected by import regulations. Therefore the only way for Philips to expand their radio tube business in Europe is to partner with - or even take over- local tube manufacturers and produce the tubes under their local brand names. In Germany this was VALVO in Hamburg, and in England Philips finds a willing partner in Mullard.

During the first World War, Stanley Mullard was the head of the valve testing department in Portsmouth with the rank of Captain. After the war Mullard starts his own company and establishes the Mullard Radio Valve Co. in 1920. By 1924 the demand for radio tubes was growing explosively and Captain Mullard needs to expand. He finances the expansion by selling half the shares of his company to Philips. A few years later Philips takes over all the shares. It was for Mullard a good deal because without the technological expertise of Philips in the areas of cathodes and metal to glass connections, Mullard would have never survived. Although owned by Philips, the tubes continue to be produced under the brand name Mullard. The brand name was and is so strong that even today original Mullard tubes are extremely popular among audiophiles and sometimes sell for a 100 to 1000 times their original price!

Back to Holland in the Twenties. In 1924 Bernard Tellegen joins the radio tube research group of van der Pol. He is then 24 years of age, and has only just graduated. Tellegen is put on a very practical problem. Due to new safety regulations, the anode voltage in radio receivers had been limited to less than 250V. At these low voltages it is difficult to generate enough output power for a loud speaker with a simple triode. Tetrode tubes - which have two grid electrodes - can generate much more power, but sound terrible due to a nasty kink in their characteristics caused by secondary emission from the anode. In an interview in 1961, Holst remembers how Tellegen suggested, “what if we insert a loosely winded third grid to push these electrons back to the anode?” This simple observation marked the birth of the pentode. It worked like a dream, and Holst and Tellegen immediately apply for a patent. It turned out to be perhaps the most valuable patent of Philips ever. It not only generated huge revenues, but it also opened the way to important cross-licenses in the area of radio.

In 1927, Philips becomes the largest radio tube manufacturer in Europe, and in 1932, little more than 10 years after the first samples were made at the research lab, Philips produces its 100 millionth’s tube.

In the meantime the popularity of radio increased explosively, and it had not remained unnoticed by Anton Philips that, whereas the price of a radio tube on average was 10 guilders, the price of a complete radio was about 200. So obviously making radio sets was a very profitable business. This combined with the fact that Philips now had their hands on a superior radio tube, the pentode, made them feel confident enough to start thinking about producing radio’s themselves. For Philips in 1926 this was something of a revolution. Until then Philips had been a component manufacturer. A radio was a system, and manufacturing a system would require a completely different approach altogether. From the onset it was clear that the receiver had to be suitable for mass-production, had to be reliable, easy to use, of high quality and reasonably priced. Visits were paid to RCA in the US to study mass production, and a thorough study was made on how something so complex as a radio could be made on a large scale by unskilled hands.

Obviously Philips Research played an important role in this for Philips completely new area. Although radio was a topic that typically would belong to the group of van de Pol, van de Pol himself found the development of a standard domestic radio receiver a bit too mundane for a man of his capabilities. It is typical for the management style of Holst that rather than forcing van de Pol to work on something he didn’t like, Holst asked Oosterhuis to study the problem. And so we have two groups working on radio: the group of Oosterhuis designing a radio according to a more conventional principle to enter the market quickly, and the group of van de Pol working on future receiver architectures.

For the final construction of the first radio two design studies were made. One design had the shape of an old fashioned circular pendulum clock. The other design, which looked like a simple rectangular box was made by Cornelius Bol. In his biographical notes, Bol recalls an amusing anecdote about how the final design was chosen. In a meeting in Mr. Anton Philips’s office, managers and specialists from the factories and research were gathered. Mr. Anton was a little late, and the specialists had taken the opportunity to already evaluate both designs. After some discussion it was clear that the pendulum shaped receiver was preferred from a standpoint of manufacturability and ease of service. At that moment Mr. Anton entered the room. Everybody was silent as Mr. Anton with his hands in his pockets walked over to the table with the two different designs. He looked at them for a moment and then said ‘We are going to make that one,’ pointing at the rectangular design. ‘But Sir,’ somebody argued, we discussed both designs and everybody thinks the other design has many advantages. ‘That can very well be,’ replied Mr. Anton, ‘but we are going to make the other one.’ Finally somebody tried, ‘But what if we put both models in the corridor of the office and we ask the people to vote!’ ‘You can do that,’ replied Anton, ‘and people might choose the other one, but we are still going to make that one.’ And so it happened.

As it turned out, the 2501, in Holland nick-named “the loaf of bread,” turned out to be a huge success. When we look at photos of the radio now, it is difficult to imagine that this was the iPhone of the twenties, but it really was! Before it you virtually needed a training to operate a radio. The selection of a radio station required a whole series of complicated adjustments. On top of that high voltage - and lead acid batteries required regular recharging and maintenance. This radio had a simple mains power supply, only a few intuitive controls, and a new and modern look. In 1927, 6000 receivers were sold, and in 1930 the production had already increased to half a million radio’s a year.

In January 1930 Hans Jonker joins the radio research group of Ekko Oosterhuis. By the time Jonker joined Philips, the development and production of radio tubes had grown to such an extent that it took a heavy toll on the resources of the research groups. It was felt necessary to organize a separate radio tube development and application laboratory close to the production site so that the research groups could concentrate on more fundamental issues. In contrast to van de Pol and Oosterhuis, Jonker is a real electrical engineer, and apart from that, a talented organizer. In the years after the war Jonker would play an important role in the foundation of the Technical University in Eindhoven as well as the city theatre. In November 1931, Jonker leaves Philips Research to organize the new development lab on the fourth floor of the radio tube production plant in the White Lady. This lab, which later became known as the “tube-lab,” would become the birthplace of virtually all the tubes which would make Philips the largest tube manufacturer in Europe.

A few years later Jonker returns to Philips Research to head the radio tube research group.

It is now the 26th of February 1935. In Germany Hitler signs a secret document ordering the organization of the Reich Luftwaffe. At the same moment in England a small wooden van is positioned in a country field for a secret experiment.

There were in England many rumors that the Germans had developed a terrible weapon that could kill a person or destroy an enemy plane by means of death-rays.

These rumors were so persistent, that a special committee in charge of organizing the British air defense, chaired by the visionary Sir Henry Tizard, asked the physicist Watson-Watt to investigate if there was any truth in these rumors.

Watson-Watt had worked on the detection of dangerous thunderstorms. To do this he had designed and built an elementary radio direction finder that on a screen gave the direction of thunderstorm activity.

Watson-Watt was quickly able to prove that anything like a death ray was nonsense, however, during his calculations he realized that if radio waves were sent in the direction of an approaching aircraft it would be possible to find the position of the aircraft from the radio waves that were reflected by the plain. On the 12th of February Watson-Watt submits his ideas to the Air Ministry in his famous memorandum “Detection and Location of Aircraft by Radio Methods.” Air Vice-Marshal Sir Hugh Dowding is not impressed and asks for a demonstration. So Watson-Watt modifies his thunderstorm receiver, and loads it into the wooden van which is now parked in a field in Daventry.

The demonstration is a huge success. Radio waves transmitted from the nearby BBC short-wave transmitter are reflected by an RAF Heyford that was used as the first Radar target. And so Brittain embarks on an ambitious air defense program, today known as radar.

A research and development team is quickly recruited amongst the most competent man of the country and Bawdsey Manor, not far from Harwich becomes the center of radar research in Britain. Huge 80 meter high antennas arise and at the start of the war Britain is protected by a Chain of 25 radar stations called “the Home Chain.” With the Home Chain system fighters could be directed to roughly the location of the enemy bombers and from their they could locate and attack them at sight. However, as early as 1936 it was realized that at night the situation would be completely different. The range at which an enemy aircraft could be seen at night was less than 300 m, and it was clearly beyond the capability of the Home Chain system to guide a fighter that accurate to its target. What was required was a Radar small enough to be installed in a night fighter.

But such an airborn radar system required a radio frequency of at least 200 Mhz which was on the edge of what was technological possible in those days. A small team consisting of A.G. Touch, Perc Hibbert and Keith Wood under quidance of Taffy Bowen was formed to look into the problem. One way or the other they managed to build the required transmitter, but a sensitive, low noise, receiver remained a problem even as late at 1939 when things really were coming to a head in Europe! Then, by a stroke of luck, the group comes into contact with B.J. Edwards, the head designer at Pye Radio, and he had exactly what they needed!

Pye radio was at that time managed and partly owned by the flamboyant C.O. Stanley. With the invention of television in 1922 by John Logie Baird, Brittan had taken the lead in the development and commercialization of television, and the BBC had already as early as 1936 started with regular television transmissions from Alexandra Palace in London. C.O. Stanley had put it into his head to play an important role in this new medium, not only by making and selling television sets, but also by offering attractive television programs by breaking the monopoly of the BBC.

To achieve this, Stanley had asked his engineers to design a television that was so sensitive that it could receive the transmissions from Alexandra Palace, even as far as Cambridge. They succeeded, and the heart of this receiver was what became later became known as “the Pye strip,” a tuned frequency receiver with no less than five brand new super tubes from Mullard, coined EF50s. Via, via the Pye strip came into the hands of Taffy Bowen who tried it in his airborn radar. The whole team was delighted, not only did it work like a dream, it was also produced in Brittan and with British valves from Mullard, at least so they assumed ……

In the meantime Philips in Eindhoven was taking a halfhearted approach towards television. On one hands Holst himself thought nothing of it, he didn’t think people would pay a few months wages for a toy which still had a pretty poor image quality while it was also not clear how the content provision would develop. Besides that, something as frivolous as television was nothing for the Calvinistic Dutch! In fact it was Holst himself who significantly delayed the industrialisation of television at Philips. On the other hand, Holst was clever enough to initiate research programs to follow the developments in the new medium on foot, both for the mechanically scanned Baird system, as well as for the electronic EMI system. The development of television had also stimulated the development of a new generation of radio or if you want television tubes which could work at the high frequencies required for television. The work in the tube research group of Jonker concentrated on two topics: The use of secondary emission to increase the gain, and the development of new tube envelopes which were better suitable for high frequency operation.

After the invention of the radio tube, it were naturally the light bulb manufacturers who started producing them. By re-using as much as possible the fabrication techniques that were already developed for light bulbs, they were able to quickly ramp-up production. In practice this meant that radio tubes, like light bulbs, were made on “a pinch,” a piece of glass tube that was heated and squeezed and which contained the electrical connections. This arrangement worked quite well for the first decade or so, but for the high frequencies required for television, the limitations of this simple technology became apparent. The long wires through the glass pinch introduced large parasitic inductances and also caused a lot of tube-to-tube variations.

Since 1934 the group of Jonker had been working on new tube constructions that would be better suitable. Designing an envelope that would satisfy all the performance requirements was not so difficult, in fact competitors came up with a large variety of technically perfect solutions, however, for Philips one of the main design constraints was that the tube also had to be mass producible at very low cost.

Working closely together with the glass factory, eventually a tube concept was developed that satisfied all the technical criteria and was simple and cheap to produce. It was the first mass-produced all-glass valve. It became known as the “Key-” or Loctal-9 tube base, and one of the first tubes to be made in this envelope was the EF50, which now, via Mullard and Pye had found its way into the heart of British air defense systems.

Not everybody is prepared to wait for coming war. In 1936 Bol immigrates with his family to the US where he buys and estate near Paolo Alto. He becomes a professor in Stanford, and after his death a large part of his estate is donated to the local community.

In 1939 Philips Research celebrates its 25th anniversary. Despite the tense international situation the fact is celebrated with a big party made up of comical sketches, music, a dance by the girls and jokes. Center of the celebrations is of course Gilles Holst who is also celebrating his 25th year jubilee with Philips.

Later that year the situation in Europe becomes more grim when Germany invades Poland. Despite an Anglo-French ultimatum, the Germans continue their blitzkrieg. So on the 3rd of September 1939 Britain and France declared war on Germany. It was now only a matter of time before Germany would direct its aggression towards Britain, most likely in the form of a massive air attack.

Fortunately the Home-Chain radar system was fully operational at that time, and also the airborne fighter radar made good progress. Up to that moment nobody seemed to have worried about the supply of EF50’s, which were so crucial for the radar system. Everybody assumed that Mullard was producing these tubes on a large scale. The truth was however, that Mullard had the greatest difficulties to produce the glass tube bases. In fact, so far all EF50 tubes, although they were labeled Mullard, had come directly from Holland!

What happened next is not recorded, but at some moment Mullard must have admitted that they had problems producing the new valve. Shocked, the military realize that for the production of one of the key components in their precious radar system, they depend on tubes imported from Holland, which itself was under an immediate threat of invasion by Germany! Through diplomatic channels, and probably also through Anton Philips himself, Theodor Tromp, the director responsible for tube development and production is asked to come to London. That was not so easy, ever since Britain had declared war on Germany all normal transport of people and goods to and from the continent had been reduced to a minimum and was under the strictest regulations. As soon as the official documents have been arranged, Tromp travels to London, and on one Saturday afternoon in February or March, after closing hours, Tromp has a meeting with Watson-Watt in the office of Eriks in the head office of Mullard in Century House, Shaftsburry Avenue, London. Watson-Watt informs Tromp that the British government is anxious to setup a large scale production of EF50s, and requests Tromp, if possible, to supply Mullard as soon as possible with all the necessary production equipment, component parts and finished EF50 that he can provide. Although Tromp obviously is left in the dark about the purpose of these tubes, he realizes that they must be of vital importance for the impeding war. This was exactly what Tromp liked. If anything, Tromp was a man of action, an organizer. As soon as Tromp is back, production is stepped up, and the truck which leaves the gate of the plant that evening in May contains some 25 thousand finished EF50 tubes and a quarter of a millions tube bases, as well as the machines to make them.

As mentioned earlier the large scale evacuation plan of Philips eventually fails because by the time that the large caravan of trucks and people reaches the large rivers, the bridges are already in the hands of German paratroopers. Most of the Philips family including Anton Philips and almost the complete board of directors reach The Hague safely. On the evening of the 13th of May they are, together with the Dutch government, evacuated from Hoek van Holland by the British Destroyer H.M.S. Windsor. Just before they board a small wooden box is delivered to Anton Philips under very difficult circumstances. The box contains industrial diamonds for the Mullard plant in Blackburn needed for the production of the tungsten filaments. It was the last the mother company in Eindhoven could do for their daughter Mullard; from then on they would be on their own.

Somehow normal life is resumed in Eindhoven. Frits Philips, who did not evacuate, is now in charge of Philips in Holland. It is for individual people as well as for the company as a whole a matter of surviving. Daily life is about finding the balance in not working for the Germans, and not working too much against them. In 1941 the people celebrate the fiftieth anniversary of Philips with a spontaneous and illegal demonstration. Starting from 1942 Tromp becomes heavily involved with the Dutch resistance movement and in espionage for the allied forces. Whereas the German tube manufacturers produce the radio tubes for the German army, Philips is ordered to produce the radio tubes for the German consumer market. Wherever possible the production is carefully sabotaged. One anecdote told to me by the son of Tromp tells how a small cylinder with chlorine gas had been hidden on the roof of the White Lady. A small tube leaked tiny amounts of chlorine into the inlet of the installation that purified the nitrogen that was used to flush the radio tubes before they were pumped vacuum. When the tubes were tested after fabrication they were perfect, but after a few weeks of use the minute traces of chlorine would render the tubes useless due to cathode poisoning.

Eindhoven was liberated the 18th of September, and only five days later Philips Research is visited by a delegation of the “Combined Intelligence Sub-Committee” headed by no one else than Watson-Watt.

The committee compiles dossiers about Nazi- and foreign scientists. In their extensive report they conclude that ‘The Germans clearly did not entrust to Philips any secret project. Thus they made substantially no use at all of the exceptionally fine laboratory organization!’ As a part of the visit, Watson-Watt gives a lecture on the discovery and development of radar and Watson-Watt thanks the Philips scientists mentioning that during the war the Mullard/Philips plants produced no less than 40% of all the British radio tubes. He confirms that the EF50, with its for that time exceptional performance, contributed significantly to the success in the Battle, of Britain and with that in the outcome of the war as a whole.

We are approaching the end of this story. The period after the war brought two important new developments: in the first place - in contrast to what Holst had thought - television really took off. During the war television had seen a tremendous development in the US and Europe was now catching up! It meant an enormous demand for radio tubes. Whereas a radio only contained only 4 or 5 tubes, a television could easily contain as much as 20 to 30 tubes. Although Philips Research certainly contributed, the real work was done at the radio tube lab in the White Lady at the Emmasingel.

Much of the success of the Philips program can be attributed to the legendary Dammers. Dammers was a master in circuit design, and in the art of combining more than one function into a single tube. Soon a form of standardization was achieved in the form of so called line-ups. Series of tubes which were designed to be used in combination with each other to form the simplest and best television receiver. These line-ups were sold to the hundreds of set makers which were then operating in Europe.

It is now hard to imagine the scale on which radio tubes were being manufactured those days. At Valvo in Hamburg alone 5000 people, mostly woman, were involved in assembly. At the peak in the fifties Philips produced 200 million radio tubes a year.

At the same time Philips Research had its hands full on something completely different all together. Already before the war, Bell labs had worked on a solid state amplifier. At that time it didn’t result in a working device because the quality of the semiconductor materials that were available before the war was too poor. That changed during the war. The search for a reliable point contact rectifier for micro-wave radar led to the development of ultrapure germanium and silicon which in 19478 resulted in the discovery of the transistor by Bardeen Shockley and Brattain.

Philips used their knowledge and patent position on ferrites to negotiate a license. It meant that whole research groups almost from one day to the other had to change focus, a change not unlike the change that we made about 10 years ago when we stopped the research on displays and optical storage. Soon the first transistors were made, and the first transistor radio made within Philips could be heard, and with the invention of the Pushed Out Base transistor Philips Research made one of the most contributions to transistor development during the fifties.

In 1954 the first transistor factory is opened in Nijmegen. Throughout the fifties Philips is the only transistor manufacturer of any significance in Europe and in 1961 Philips produces 20% of the world market.

Over the past 100 years Philips Research has been the origin of many great innovations: the pentode, the all glass tube, ferroxcube, LOCOS, the CD… We also - as we say in Holland – “sometimes missed the boat.” To be honest, we were late with radio, radio tubes, television, transistors, and LEDs … But almost always, through a combination of: craftsmanship, ingenuity and shrewd business insight we came out for the best. Even today, where the whole light industry is going through a complete paradigm shift, we have been able to maintain our number one position in lighting. I dare to say that in all those moments of change and peril, our research organization played an important role bringing the innovations that made the difference.

Thank you for your attention

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