DE1155477B - Process for the production of a cathode ray tube with colored stripes and index stripes - Google Patents

Description

GERMAN

PATENT OFFICE

kl. 21a ¹ 32/54

INTERNATIONAL KL.

H04n; H01j

S 69872 Vraa / 21a ¹

REGISTRATION DATE: AUG U S T 10, 1960

NOTICE
LOGIN
AND ISSUE OF THE
EDITORIAL: OCTOBER 10, 1963

The invention relates to a method of manufacturing a cathode ray tube having a Screen, on the back of which is facing the cathode, parallel in repeating groups Color strips are arranged, which emit light of different colors when the electron beam hits and are covered on their back by a layer that reflects the emitted light, Each group of colored stripes has index stripes that appear when the electron beam hits it Generate index signals that are processed by a receiver located on the one facing the cathode Side of the screen.

In known embodiments of such screens, the color strips are initially with a reflective coating layer made of aluminum. Then you bring the index strips either on this reflective coating, or you can embed the index strips in the reflective Coating a. Both manufacturing processes have the disadvantage that the thin reflective layer when applied or embedding the index strips is easily injured.

In order to avoid these disadvantages, those applied to the screen are according to the invention Color strips are covered with a plastic layer, and the index strips are placed on this plastic layer upset. Finally, the side of the screen facing the cathode is in this way with the reflective layer coated so that this is continuous and therefore strong on the colored stripes reflective, on the other hand interrupted on the index strip and thus less reflective. This Method has the advantage that damage to the sensitive reflective layer is therefore is not possible because it is only applied at the end, d. H. after already having both the color streaks as well as the index strips have been made. The tube made with this process becomes the the most important demands that are to be made of the same or of the screen, which are the following claims are involved:

a) The colored stripes should have a reflective layer behind them, for example a thin layer of Aluminum, which is able to transmit cathode rays with little attenuation, however to increase the light output of the colored strips.

b) In order not to impair the colorimetry of the image, only a small amount of light should come from the index strips penetrate into the reflective layer. Method of manufacture

a cathode ray tube with colored stripes

and index strips

Applicant:

Sylvania-Thorn Color Television Laboratories Limited, London

Representative: Dr.-Ing. E. Liebau, patent attorney, Göggingen via Augsburg, V.-Eichendorff-Str. 10

Claimed Priority: Great Britain August 14, 1959 (No. 27 943)

Peter Henry Mattingly and John Kenneth Oxenham,

London,
have been named as inventors

c) As much light as possible should get from the index strips to the light multiplier, the is used to generate the indexing signals.

d) Only very little light should reach the light multiplier from the colored stripes, as this is the Signal-to-noise ratio decreased.

The plastic material is chosen so that it forms a smooth surface on which the metal coating is located the reflective layer is continuously deposited, while on the one consisting of phosphorus Index strip results in a discontinuous reflective coating. The continuous reflective layer has significantly better reflective properties than the interrupted layer on the index strip.

According to the further method, the plastic layer is removed in a firing process.

The invention is explained in more detail in the description of the exemplary embodiment shown in the drawing explained.

Fig. 1 is a block diagram of a receiving device including one made in accordance with the invention Tube;

309 727/104

Fig. 2 shows, greatly enlarged, in cross section a detail from a produced according to the invention Screen.

In Fig. 1, a portion of the glass bulb of a cathode ray tube is shown at 10, this glass bulb a transparent face plate 11, covers 12 to be described later, and a thin aluminum layer 13, a window 14 being provided in the layer 13. Behind the window 14 there is a light multiplier 15. Signals are picked up and fed into receiver circuits 16 processed, whereby color signals passed through the color circuits 17 to the electron gun 18 of the tube to control the intensity of the cathode ray zxi. Indexing signals from the light multiplier 15 are fed to the color circuits 17 to the color signals in the correct order To get electron gun 18. Operating voltages are supplied from a battery 19. Since the apparatus shown in Fig. 1 is well known, further explanation of this figure becomes unnecessary viewed.

A method of manufacturing a screen according to the invention is described with reference to FIG. Color phosphor strips R ₁ G and B are first applied to the front panel 11. In this example, protective tapes D made of an opaque material are applied between the colored strips, although this is of course not essential. A layer N of nitrocellulose is applied over the exposed surface. Index strips / are then applied and these may consist of a phosphor, such as that known as P16, which emits light primarily in the purple and ultraviolet parts of the spectrum. The exposed surface is then coated with aluminum using any suitable method known in the art to provide a thin but continuous coating of good light reflective properties at A ₁ but an intermittent coating over the index phosphor at A ₂ . For example, coating A ₂ can transmit approximately 20 to 25% of the light transmitted by the index strips.

The addition of aluminum is preferably effected by evaporation, and it has been shown that that where aluminum is evaporated onto the smooth nitrocellulose sheet, a continuous coating is easy can be formed, while on the rougher surface of the index strip the coating is not continuous is.

The tube is fired to remove the nitrocellulose N layer.

Since the color phosphor strips R, G, B are protected by the continuous aluminum coating A ₁ on the rear side, it is clear that the screen described has the properties a) and d) mentioned above. Property b) is not of great importance since the light emitted by the index strips is hardly, if at all, visible to the human eye. Requirement c) is not fully met, but the amount of light received by the light multiplier is sufficient.

Claims (2)

PATENT CLAIMS:
1. A method for producing a cathode ray tube with a screen, on the back of which, facing the cathode, parallel color strips are arranged in repeating groups which emit light of different colors when the electron beam hits and are coated on their back by a layer that reflects the emitted light, wherein Each group of color strips includes index strips which, when the electron beam hits them, generate index signals which are processed by a radiation-sensitive receiver located on the side of the screen facing the cathode, characterized in that the color strips (R, G , B) coated with a plastic layer (N) and the index strips (/) are applied to this plastic layer and that finally the side of the screen facing the cathode is coated with the reflective layer (A ₁ , A ₂ ) in such a way that it is on top the Far b stripes are continuous (A ₁ ) and thus highly reflective, whereas on the index stripe it is interrupted (A,) and thus less reflective. 2. The method according to claim 1, characterized in that the plastic layer in one Combustion process is removed. Considered publications:
U.S. Patent No. 2,633,547;
Australian Patent No. 157,632. 1 sheet of drawings © 309 727/104 10.