DE737997C - Electric discharge tubes for the visual display of voltages - Google Patents

Description

GERMAN EMPIRE

ISSUED JULY 30, 1943

REICH PATENT OFFICE

PATENT LETTERING

JVI73J997 CLASS 21g " GROUP 13

N 42180 VIII φι g

Gerrit van der Hoeven in Eindhoven, Netherlands,

has been named as the inventor

Philips Patent Administration G. m. B. H. in Berlin

Electric discharge tube for the optical display of voltages

* Patented in the German Reich from July 2, 1938

The invention relates to electrical discharge tubes for the visual display of Stresses consisting of an at least partially transparent piston in in which an electrode system is arranged, which inter alia. consists of a cathode and a Anode that can light up completely or partially, e.g. fluorescent, which light phenomenon can be observed from the outside through the upper end of the piston.

There are already known electric discharge tubes in which, for example bowl-shaped anode is covered with fluorescent material, which is under the influence of incident electrons are completely or partially made to glow, which light phenomenon observed from the outside through the top of the transparent flask can be. The size of the light phenomenon depends on the one to be displayed Voltage that is applied to a specific control electrode. There are already such tubes are known in which a glowing cross is visible on the anode, the width of the legs of this cross being a measure of the voltage applied. Such a tube contains an electrode system in which between the fluorescent The anode and the cathode are arranged in rod-shaped or strip-shaped control electrodes, their voltage and thus also the width of the fluorescent surface of the one to be displayed Voltage is dependent. According to a particular embodiment of this known The tube becomes the control electrode with the anode of a triode or pentode amplifier system connected and the voltage to be displayed to the control grid of the amplifier system created. The voltage applied to this grid controls the current through the amplifier system and therefore the potential the anode and the associated control electrode. The size of the fluorescent Area is from the potential of the control electrode and therefore from the voltage to be displayed addicted.

Optical voltage indicator tubes have also been proposed in which the display anode is designed so thin that it is completely or by incident electrons is partially made to glow. With these tubes, too, the size of the light

appearance depends on the voltage to be displayed.

It has now been found that with such tubes the contrast between the illuminated Part of the anode and the non-illuminating part is often too small to allow for something that is noticeable from the outside when it is relatively strong Light can still be observed sharply. The reason for this low contrast can include the fact that the light phenomenon is both fluorescent how glowing anode is very weak. In addition, tubes with fluorescent anodes in particular tend to grow over time t5 decrease light intensity, whereby the contrast becomes even lower. Another cause of the poor perceptibility of the appearance of light lies in the execution of the above End of the piston. You're at this Bauao kind of the usual dome-shaped top of an ordinary electric discharge tube went out. This upper end of an ordinary tube is strongly curved outwards, so that the inside of the tube cannot be observed sharply enough. Prepared for the usual amplifier tubes this deficiency is not a problem, but with indicator tubes it is of course necessary to be able to perceive the luminous phenomenon inside the bulb without distortion. For this purpose one has with such The indicator tubes have already given the upper end of the piston a somewhat flatter shape. Regardless this flattening but the original curvature can only be changed a little to enable both a comfortable manufacture and a good resistance to maintain against external pressure.

There is also known a cathode ray tube in which the upper end, i.e. H. the end, through which the fluorescent image is viewed is curved inward. The fluorescent The mass is attached to the inside of the bulb on the curved glass wall. Every fluorescent image is thus created on a curved surface, and then it is possible to enlarge this image with the help of an uncorrected lens. The fluorescence image of such a So tube is also very small.

In the case of an electrical discharge tube for the optical display of voltages with a at least partially transparent piston, inside of which there is an electrode system with a cathode and an anode, which are wholly or by incident electrons can partially be made to light up and at some distance from the vessel wall is arranged, is according to the invention according to the wall part opposite the anode, through which the lighting of the anode is observed from the outside, bent inwards.

By bending the upper end of the piston inward, it becomes like the inventor on the basis of tests has established the contrast between the illuminated part and the non-illuminating part of the anode is greatly increased. This will increase the contrast caused by the fact that there is a difference between the beam path that of comes out inside, and your beam path, which hits the tube wall from the outside. These last rays are partially * weakened and partially bent in such a way that they can no longer fall into the eye of the observer. As a result of this difference the contrast between illuminated parts and non-illuminated parts is increased.

In the known cathode ray tube with an inwardly curved wall, a Contrast increase does not occur because the fluorescent material directly hits the glass wall is applied, while in contrast to this, a besummier in the tube according to the invention There is a distance between the illuminated anode and the glass wall.

The upper end of a tube according to the invention can now be carried out in various ways will. It is Z. B. a construction possible, wherein the upper end of the tube is bent inward and a flat base Has. According to another embodiment, it is possible that the upper end is a Represents part of an inwardly curved spherical surface. The latter embodiment is particularly advantageous because it has been found to be particularly useful in this construction the contrast between the illuminated and the non-illuminated part of the anode is sharply perceptible.

Tubes according to the invention can be made in very different ways. Man can, for example, make use of a blown glass bulb, the upper one End is first bent outwards as usual and then bent inwards, or you can blow the piston into the desired shape right away. With another Embodiment, the piston is made of pressed glass, the final Shape is produced by pressing. According to yet another embodiment a piston is used that is largely made of metal and only the top of which is made of glass, the is then bent inwards according to the invention. The invention is based on a drawing, in which some embodiments of a tube according to the invention are shown, explained in more detail.

In Fig, ι is a tube according to the invention shown, the top of which is curved inward and flat.

Fig. 2 shows a tube, the upper end of which is part of a sphere.

In Fig. 3 is an electric discharge tube having a largely metal one Piston shown, of which only the upper end is made of glass.

ίο In Fig. ι there is the actual display electrode system of a cathode i, an anode 2 and an intermediate one Control electrode 3. Furthermore, a cathode 4, a grid 5, is located in the tube

and an anode 6 existing amplifier system arranged. The control electrode 3 is directly connected to the anode 6. The glass bulb 7 of the tube is bent inwards at the upper end and has the flat part 8 through which the light phenomenon on the anode can be observed. The tube also has a normal base 9 with contacts 10. Only the piston of a tube according to the invention is shown in FIG. 2, the upper end 11 being bent inwards and representing part of a sphere. 3 shows a piston of a tube according to the invention, the wall 12 of which is made of metal, to which an inwardly bent glass part 13 is melted at the top.

Claims (4)

Patent claims: 1. Electric discharge tube for the visual display of voltages, consisting of from an at least partially transparent bulb in which a cathode and one at a distance from the vessel wall located anode, which can be made to light up in whole or in part by incident electrons, are provided, characterized in that the upper end of the piston, through which the anode is illuminated from the outside is observed is bent inward. 2. Electrical discharge tube according to claim 1, characterized in that the upper inwardly bent end has a flat base. 3. Electrical discharge tube according to claim 1, characterized in that, the upper end of the piston is part of an inwardly curved spherical surface represents. 4. Electrical discharge tube according to claims 1, 2 or 3, characterized in that that the piston is made of metal and at the upper end with a inside bent glass part is provided. '. For this purpose ι sheet of drawings