DE2015578A1 - Crt screen for colour television - Google Patents

Abstract

The screen which has balanced colour and mono-chrome reproduction of improved brilliance comprises (1) a red phosphor comprising a white Eu activated rare earth oxide body with particles substantially parallelo-pipedic, (2) a green phosphor having a characteristic body colour which contributes to the improved white brilliance and (3) a blue phosphor of increased brilliance. (1) is pref. of the general formula:- Y1-xGdx)0.90-0.99Eu0.01-0.10 2O3.

Description

Color cathode ray tube and method of manufacturing it priority April 2, 1969 - U.S.A. - Ser.No. 822 794 Summary It becomes a patterned Three-color screen for a color cathode ray tube described, which consists of a There is a combination of phosphorus that provides a 3-picture display with reduced luminance results, and a process for its manufacture. The red-emitting phosphor is a europium activated rare earth oxide with parallelepipedic particles, the blue-emitting phosphorus is a zinc sulfide compound activated with silver, which is synthesized to have minor amounts of selected inclusions and the green-emitting phosphor is an activated zinc-cadmium-sulfide material, that does not show a noticeable shift in shade or change in body color Reason for the tube processing shows. On the back of the screen a substantially tensioned aluminizing film is disposed; the umbrella itself contains potassium silicate.

PRIOR ART The invention relates to cathodoluminescent screens, and especially an improved combination of phosphorus ingredients for one Color cathode ray tube screen and a method for its manufacture.

The usual cathode ray tubes that are usually used on color television used to work with an internal facility with at least one Electron beam shaped according to correspondingly applied signals and transferred to a patterned one Cathod'luminescent screen is directed. A patterned umbrella of this type exists usually made up of a multitude of phosphorus groups that are considered to be in mutual separation standing strips, Stflbe or points are arranged, which individually respond to electron excitation which are usually emitted as rays by separate electron guns so that luminescent shades of the colors red, green and blue are supplied will.

An effective three-color cathodoluminescent screen in a cathode ray tube for television, three color phosphors will be the screen combination carefully selected with special attention to the definitive color characteristics, wid hue, degree of saturation and own density. Taking this into account Characteristics is very important because a mixture of all three hues creates a balanced one White should deliver a desired color temperature when all three phosphors are used at the same time be stimulated.

The desired white is a relative value of a balanced "white", shown on a standard C.I.E. color diagram will can. Such a white, which is usually referred to as standard lighting C, is defined by the intersection of the x-coordinate 0.310 with the y-coordinate 0.316.

Another white currently used in many color television applications has a slightly lower x-value and is called white at a temperature of 93000 K designated. which is defined in the C.1.E. system by x = 0.281 and y = 0.311.

Similarly, other values of relative white may vary depending on the the requirements. In the following description, a white temperature value is intended of 9300Q K can be considered representative of color television applications.

When choosing the right luminescence ratios the red ,, green and blue additive primary colors of a screen combination to generate the desired Different color-emitting phosphors become white with careful consideration of their compatible contributions to the color qualities. Unfortunately have some of the phosphors that have hue and saturation compabilities as screen components exhibit uneven luminance effects to produce the desired white Reason of their chemical composition. At times it became a conscious mindset or reduction of the luminescence of one or more of the bright phosphors applied, to get a luminance like that of the less effective Phoephor baw. Phosphors of the special shield combination. Such a compromise procedure reduces the overall screen luminance.

Another possibility, the phosphor luminance imbalance Adjust in operation, consists in that the intensities of the respective impinging Electron beam is regulated so that the correct luminance of each phosphor the combination is delivered. The less effective color emitting phosphor requires thus electron beam currents of noticeably higher value than them to the Stimulating the lighter phosphor components of the screen combination are required. The differences in operating intensity of the various electron guns that working at the same time to produce the desired white are usually used in Expressing at least two gun flow ratios denoted, for example the ratio of red to green, (R / G) and red to blue (R / B). For example, if the three cannons working at the same time to produce the desired white indicates one R / G cannon ratio of 0.9 t 1 that an electron beam current of 10K lower Intensity from the red cannon is demanded than from the green cannon to the necessary to obtain individual luminance from the red or green emitting phosphor. Similarly, a gun ratio R / B = 1.4: 1 means that the red gun Must deliver 40% more beam current than the blue cannon to the white field simultaneously to complete the stimulated screen satisfactorily.

The body's own color, which corresponds to the degree of transparency or opacity of the color-emitting phosphor crystal in question is a important characteristic of cathodoluminescent phosphors. The phosphors that Substantially translucent, are usually considered to be white in body color CLASSIFIED WITH BETTER LIGHT TRANSMISSION. With the use of phosphors made of rare earths, especially red-emitting materials, the higher moisture density show than previously used phosphors. there was an improvement in the screen luminance in white. For example, resulted in the use of a red-emitting component on the basis of a rare earth, for example yttrium vanadium activated with europium, that in combination with a compatible green-emitting component, for example with silver activated zinc-cadmium-sulfide, and a compatible blue-emitting one Component, for example zinc sulfide activated with silver with luminance blocking additives a Colored cane umbrella, the opposite of older usual umbrellas However, it was noted. that both the hue of the emitted light as well as the body color of the green-emitting one activated with silver Zinc-Cadmium-Sulphide-Phosphorus to shifts due to the temperature range tends to occur during tube manufacture.

Such variables affect the quality of the picture of the subject Umbrella combination. So this screen is an improvement over older ones Umbrella combinations, however, there is still a desire to increase both of the luminance- all also of the hue characteristics of color picture tubes to the To improve the quality of the color presentation in strong ambient light.

Summary of the Invention The invention is intended to provide those described Disadvantages are reduced and an improved color cathode ray tube be made available with an improved method luminescent screen, as well a method for its manufacture.

The invention is also intended to provide a discrete combination of color-emitting Phosphors are being made available that make up an improved color cathode ray tube screen can be made available with improved luminance and hue characteristics.

The invention also aims to provide a color cathode ray tube be made available with an umbrella that combines a combination of compatible, having color-emitting phosphor, with which an improved white luminance can be presented.

According to one aspect of the invention, therefore, an arbbild- Katho @ enstrahlröhre made available with a device with dr generating a number of electron beams and directed so that they appear on a three-colored cathodolumineeæenz screen hit, the electron-sensitive red, green or blue-emitting phosphor components having. The red-emitting material is an oxide activated with europium rare earth with parallelepipedic particles, consisting essentially of gadolinium oxide, Yttrium oxide or mixed gadolinium-yttrium oxide.

The green-emitting phosphorus is a zinc-cadmium sulfide, which is none shows a measurable shift of the hue or the body color due to the temperatures, that occur during tube manufacture. The blue-emitting phosphor is a silver activated zinc sulfide compound so synthesized that it has minor amounts of selected inclusions. The three color-emitting Phosphors are selectively combined in such a way that a three-component system results, with which a patterned screen is built up, the considerably improved luminance, Shows color purity and resolution.

To prevent the temperature-dependent changes in silver activated zinc-cadmium-sulfide as green-emitting phosphorus is in the tube der Weisé treats that this phosphor has an improved hue and a better one Body color that is close to the values in question prior to tube manufacture lie.

Further objects, advantages and possibilities of the invention result from the following description in conjunction with the drawing; show it = 1 schematically shows a section through a typical color picture cathode ray tube with their essential characteristics; Fig. 2 schematically and in perspective a portion of a color picture cathode ray tube with a discreetly patterned phosphor screen; Fig. 3 parts of the. Umbrella structure; Fig. 4 shows a conventional C.I.E. - Color diagram with the Parb coordinates of two three-color screens according to the invention; Fig. 5 a usual eye sensitivity curve with the dominant wavelengths of the invention Umbrella combination; and FIG. 6 graphically the. improved luminance of the inventive Umbrella.

In Fig.1 a color picture cathode ray tube is shown as it commonly used in television applications. The tube consists of an evacuated one Piston 13 with a viewing plate 15, a funnel part 17 and a retracted one Neck 19. A base 21 is attached to the connection of the neck, lead through the conductor, with which the tube electrodes are connected to the associated receiver circuit will. In the neck there is an electron beam generating device 23 in the form from one or more electron guns, one or more of which are electron beams 25, which are used in the operation of the tube. A cathodoluminescent screen 2? Which consists of a pattern of color-emitting phosphors is on the Inside 29 of the transparent viewing plate 15 is arranged. In the piston there is a Madken or grid electrode 31 with a large number of openings 33, in the vicinity of the screen 27. In the case of the tube type according to FIG 31 mainly used to either the electron beam 25 to focus or deflect, or to mask or to mask the beam to mask and focus to get the desired electron impact on the patterned Effect screen 27 The special grid electrode and screen structures as well the applied voltages determine the special operating mode in a known manner.

In particular in Figs. 2 and 3 is the principle of a special embodiment a cathode ray tube, which has a screen and grid electrode structure as used in a three-gun shadow mask tube.

In this case, the Kathodolumineezenzechirm 27 consists of one Pattern of three-color phosphor groups in a variety of red, green and red blue-emitting phosphorus dots. The three electron guns of the electron generating device 23 are arranged essentially at equal distances from one another in such a way that that a static convergence of the respective electron beams in the central Mask opening is caused. For example, the three electron guns emit 37, 39 and 41 single-elnen electron beam 37 ', 39' and 41 ', which are so directed are that they converge in an opening 33 in the mask 31. There they cross each other and keep walking until they are on a triad of related red, green- and blue-emitting phosphor points 43, 45 and 47, respectively, impinge on the part of the screen pattern placed on the transparent viewing panel 15 is. As will be described later, the electron beam currents are of the individual gun according to the luminance efficiency of the different color-emitting Phosphorus Adjusts that compattbel make the discreet combination that in that special umbrella pattern is used.

A color screen with improved earbone and luminance characteristics It takes more than a simple substitution of phosphorus to achieve this. About the compatible parameters of the additive primary colors of a three-color phosphor combination To achieve this, a great deal of creativity is required because of the interaction between the color components. This is clear from the description of a Embodiment of the invention consisting of a red-emitting, activated with europium Oxide consists of a rare earth with a white body color, the particles of which are higher Have moisture density under electron excitation, a green-emitting one with Silver activated zinc sulfide-cadmium sulfide-phosphorus used during the tube manufacturing process is treated so that it has a characteristic body color that is close that it has before the tube processing, resulting in an improved Contributing to density under electron excitation, and a blue-emitting one, with Silver activated zinc sulfide compound that shows better luminance because they have smaller inclusions of elements from groups la and 2a of the periodic System together with a small amount of aluminum.

An embodiment of a three-color phosphor combination ox after The invention is to be discussed with reference to Fig. 4, in which a common C.I.E. with color defining x and y coordinates shows by the hue and degree of The perimeter of the horseshoe-shaped figure is defined a monochromatic place with the blue and red ends of the spectrum through connected by a line representing a place for pure purple. Within the location of the color chart is a range of colors for which normal human Eye is sensitive. A consecutive series of numbers the notated near the curves indicate pure spectral wavelengths in millimicrons (n µ) an, equal to nmo The hue of any color can be defined by s and y coordinates To be defined. Due to the peculiarities of measuring instruments, the x and y values, which are mentioned in the application, essentially in a range of + 0.004 units.

As mentioned earlier, white is a relative value of the combined additive primary color components. The white of the temperature of 9300 ° K as it is for The purposes of the Bosch description should be considered representative, iet by denotes the letter K, where the values x. 0.281 and y = 0.311 A color picture cathode ray tube used for telephoto purposes is said to be primary colors show that are close to those caused by the color excitation system used It is true that there is a certain spectral overview for each of the additive Primary tones allowed, however efforts will be made to each of the three primary tones to be defined in such a way that each vertex of its triangle is formed in the C.I.E. diagram that encloses such a range of hues that it becomes as full as possible Color rendering area results.

An embodiment of the three-color phosphor combination according to the invention, which shows improved luminance will now be described in more detail. The red-emitting probe Phosphorus component according to the invention is an oxide activated with europium rare earth with perallelepipedic particles, namely a phosphor with white Body color, consisting mainly of gadolinium oxide, yttrium oxide and mixed @ m Gadolinium Yttrium Oxide is made up of what is empirical in mole values by the following Formula is expressed: [(Y1-xGdx) 0.90-0.99Eu0.01-0.10] 2O3 where x is between 0 and 1 lies.

The term "parallelepiped" is intended to include the well-defined forms These new phosphor particles describe in terms de their geometric outer surfaces concern, this term is not intended to have any specific relation to the internal crystal structure of the particles have The yttrium-oxide-phosphorus particles according to the invention are in essentially cubic and have six essentially square-like faces while some of the mixed crystals of gadolinium yttrium oxide have a parallelepiped structure show in which at least four planes have a more rectangular shape. A special one Example of a red-emitting rare earth oxide with parallelepipedes Particles are defined as (Y0.940-0.990Eu0.01-0.06) 2O3 those in the finished screen C.I.E. color coordinates, which are essentially represented by the values x = 0.644 and y = 0.330 are defined. A straight line K-R-S, the one from point K, the 93000 K white passes through the x and y coordinates denoting point R, intersects the Monochromatic curve at point S, creating a dominant wavelength of essentially 612 m (x is designated. The color shade in question is essentially 94% saturated. Sea parallelepipedic phosphorus is synthesized by a new process, whereby it has the same shape and larger particle size, and it results thereby a better luminance after electron arrangement compared to known, available Yttrium oxide as phosphorus, which is an agglomerate of irregularly shaped,? A subdivided Particles that newly cover a large size range. Since the parallelepiped Rare Earth Oxide is larger and more uniform in particle size can be it will absorb a higher europium content at luminance levels that are the same those of older oxides activated with low europium content, without any Luminance losses result, and therefore the new phosphor has a redder hue, compared to the regular agglomerate whose coordinates are essentially x = 0.628 and y = 0.347, which is denoted by R 'on the line K-R'-S' in Figure 3 is. The parallelepiped material approximates the hue characteristics of the mentioned yttrium vanadium and is advantageously lighter than the latter Phosphorus.

The red-emitting parallelepipedic phosphor particles can for example, be prepared in such a way that a suitable oxalate of the rare Earth is made by precipitating the oxalate from an acidic, aqueous solution which contains the source material for the rare earth, the oxalate of the rare Earth is separated as a solid, the solid oxalate of the rare earth with a aqueous solution of oxalic acid is washed and then treated with heat, around the oxalate of the rare earth into an oxide of the rare earth suitable as phosphorus Transform earth.

The manufacturing process for a red-emitting phosphor the base of rare earths with parallel @ pipedischon particles is the subject of a separate application filed at the same time, attorney's file number: 8 6 P 100 D. This method is used extensively to increase and control particle size. of rare earth oxides in the sllg @ m @ inen g @@ ign @ t.

The novel particle shape of some of the nouen phosphors on the The basis of rare earth oxides enables the phosphors to have a broader application and the phosphorus addition itself is therefore the subject matter one further patent application, attorney's file number: s 6 P 99 Do As blue-emitting Phosphorus is commonly used in color cathode ray tubes with silver activated ' Zinc sulphide used0- In conjunction with vanadate activated with europium as a red-emitting one Phosphorus often requires the density of the blue-emitting material suppress or lock to maintain proper cannon ratios.

It was found that a much brighter, blue-emitting Phosphorus in the three-color combination is advantageous in which the described, red-emitting, europium activated rare earth oxides with parallelepipedic Particles can be used as phosphors0 Further experiments have shown that a greater luminance in the new phosphor combination is desired than it is through regular, silver-activated zinc sulfides that are free from luminance inhibitors Accordingly, additional efforts have been made in the Searching for higher excited luminance will result in a new blue-emitting Phosphorus with a white body color is used from one activated with silver Zinc sulfide compound is made up of smaller inclusions of elements of the group 1a and 2a of the periodic table together with a small amount of aluminum. The total amount of the various inclusions is less than about 5% of the weight the total amount of silver activated zinc sulfide present. More precisely, the minor inclusions consist of the following elements, expressed in Weight percent: between 0.01 and 0.10 of an alkaline earth metal, mainly barium, Magnesium and / or calcium; 0.01 to 0.10 alkali metal, mainly sodium, potassium and / or lithium, and 0.01 to 1.00 aluminum This zinc sulfide compound is activated with 0.02 to 0.05 percent by weight silver. Disser new blue-emitting Phosphorus is synthesized from the zinc sulfide. A number of is subjected to specific flows containing the elements of inclusion. In general will these elements are embedded in the zinc sulfide before this3 is burned to produce the to generate new phosphorus compound. It was found that under electron excitation this new phosphor 25 to 50 percent higher luminance compared to the usual, zinc sulphide phosphorus activated with silver and of essentially similar hue shows and without brightness inhibitors at the maximum attainable density level can be used, as will be explained. For example, the new blue-emitting Zinc sulfide phosphorus which is indicated at B in Fig. 3, small inclusions of magnesium, Sodium and Aluminum on This phosphorus composition gives essentially the color coordinates x - 0.152 and y = 0.068, a straight line K-3-V -vcm point K through the z and y coordinates of point B intersects the monochrome curve V, so that a dominant wavelength vo; essentially 462 mµ is designated. The blue hue of the improved phosphor is essentially 87% saturated.

When choosing the green-emitting component of the improved phosphor combination several interrelated factors need to be considered. The excited phosphor is said to show a luminescence, the color tone and density of which are different compatible with the other phosphors of the combination that work together with it is, through in-depth optical observations of color picture tubes with green-emitting Phosphors showing variants of chromaticity have been found to be a certain desaturation of the green component can be allowed without affecting the operating behavior the color rendering is significantly impaired. It was also found that that when the hue of the green-emitting phosphor increases to higher x-coordinate values and smaller y-coordinate values are shifted, lower beam currents from the Red and blue electron guns are required to make a white of the desired @ en Parbe temperature to get. Since in television there is usually a specified total beam current required, it enables the reduction of the current from the red and blue cannons, that the green gun delivers more beam current, so that there is a greater white luminance for a given total amount of beam current. Through this process the luminance of the green phosphor component in the white field is effectively increased, although the efficiency of the phosphorus remains essentially the same.

The green-emitting component that is responsible for the improved three-color combination selected is a zinc sulfide-cadmium sulfide-phosphorus activated with silver, in which a part of the cadmium sulfide in the range of 40 to 42 percent by weight of the total host weight, the amount of silver activator in the range is from essentially 0.0005 to 0.020 percent by weight. This phosphor has off-white as the body color, it is somewhat yellowish, which indicates the present is returned by cadmium sulfide in the material. It is known that this is body color of zinc sulfide-cadmium sulfide phosphors activated with silver become the orange part The spectrum shifts when the phosphorus in question is subjected to high temperatures becomes, for example, d20 to 450 ° C, as it is during cathode ray tube machining appear. It is also known that the hue of the luminance emission, which is by electron excitation of the phosphor, also to the orange part of the spectrum shifted when the phosphor is exposed to high temperatures. It results there is also a loss of luminous flux, which leads to a drop in phosphor efficiency which results from the oxidation of zinc sulfide and cadium sulfide, from which it is also assumed that thereby the light absorption properties of the Phosphor crystals in the blue spectral range due to the stronger orange body color be increased0 It would be found experimentally that by treating the manufacture Sample of the color screen described before painting with a 0.01 to 1.00% strength aqueous solution of potassium silicate itself has a decrease in the amount of body color shift and the hue shift of silver activated green phosphor gives the results from the high temperatures encountered in the pipe treatment Such a reduction in the respective postponements results in a 5 to 10% increase in green and white field luminance levels. According to Figure 4 has an untreated, silver-hardened zinc sulfide-cadmium sulfide-phosphorus component a hue shift, due to the tube processing, which is labeled "G '" and is essentially defined by the coordinate values x 0.325 and o = 0.605. The line K-G'-T 'defines a dominant wavelength of essentially 554 mµ and a color saturation of essentially 85%. When the finished screen with for example, a 0.5% aqueous solution of potassium silicate is treated, If the zinc sulphide-cadmium sulphide activated with silver shows a reduction in the hue shift, as indicated by the point G, which roughly has the coordinates x = 0.313 and y - Has .590. The line K-G-T defines a dominant wavelength of essentially 552 mµ The color saturation is essentially 75%, i.e. it is smaller than at u @ treated phosphorus. Accordingly, it turns green, less red lt and blue B to get the desired white K of 9300g t0 vator material are between about 0.005 to 0.030 weight percent swabs and about 0.005 to about ' 0.060 weight percent aluminum. A special example of this type of green-emitting Phosphorus is a phosphor in which the amount of cadmium sulfide is about 7 to 8 percent by weight of the entire host, and in which the amounts of co-activator material between about 0.010 and 0.025 weight percent copper and about 0.007 and 0.030 weight percent Aluminum lying. Because of the low percentage of cadmium it has co-activated Matsrial a whiter body color than that described above, activated with silver Phosphorus with a higher cadmium content. It also shows such a co-activated Phosphorus no change in body color and no change in shade due to the Tube processing temperature. The co-activated material is therefore not required Potassium silicate to be treated to get the body color you want and the one you want Maintain hue. The x and y color coordinates are also in Fig. 4 in the point G, they are stwa x = 0.317 and y = 0.593. The line K-G-T defines a dominant wavelength of essentially 552 mµ. The color saturation is essentially 75%, which is essentially the saturation of the treated, with silver activated, green-emitting phosphor. So it was found that each of the described green-emitting materials is about the same amount of red R and blue B in order to obtain the desired white K of 9300 ° K.

The green-emitting, co-activated zinc sulfide-cadmium sulfide-phosphorus can, for example, be prepared in the manner The d @@@ farh @ emitting Phosphorkomponsntel d @@ verbasserten Fonh @ nation @ earth individually as part of the screen pattern Arranged in a similar way, example sw @@@@ can be a fo @ ografischs printing technique we @ an used to manufacture the umbrella wobai a lichtampfindlicnes @material for this purpose, the color-changing phosphor is used on the viewing panel 15 to tie the tube In such a process, @as Pame @ l with a thin @@ n film of a licntensitive substance coated, for example with dichromet sensitized polyvinyl alcohol and one of the color-effecting phosphor materials. This layering can be done in the manner that initially in film light-sensitive substance is applied to the plate, and then dry @ s Phosphor powder is deposited, or it can be a suspension of the phosphor be applied in the light-sensitive substance, as in the usual Aufechlmmingstechnik. The coated plate is then essentially ultraviolet through the perforated mask 31 exposed, which is inserted into the plate and positioned in a suitable manner, to cause the photosensitive substance to polymerize or harden and adheres to the surface of the panel, according to the exposed point pattern, holding the respective phosphor particles on it, the parts of the screen, which are not exposed because they are covered by the remaining parts of the mask are then removed in a @ m development step in which the expose Parts of the photosensitive layer with a suitable one Solvents are removed, for example water.

This procedure is used for the precipitation of any light-emitting Repeated phosphor pattern that makes up the screen, robei dis succession the color precipitation is not critical The multitude of points each the -related to each other @ n phosphor patterns are essentially compact and uniform structures with acceptably rough surfaces into which the Phosphorus particles are well embedded.

Zinc sulphide-cadmium sulphide activated as green-emitting phosphorus with silver is used in the umbrella combination, it has been found that it is favorable then an aqueous solution of at least one oxygen-containing compound of Sodium, potassium, lithium and / or silicon to be applied Including alkali silicates and -Hydroyde to understand.

An alkali silicate, for example potassium silicate, is used in this Context considered when a 0.01 to 1.00% aqueous solution of this alkali compound is applied over the patterned @ n screen after the third screen pattern in the way has been developed that it will be retained during the subsequent screen processing will. An example of such a solution is a recipe for aur molar basis, which in a molar ratio of 3.5 parts of silicon dioxide (SiO2) to 1.0 part of potassium oxide (K20) included. It has been found that the application of aluminum silicate causes the shift of the hue and the size of the body color change of the green- @ mittierend @ n, with Silver activated zinc sulfide-cadmium sulfide-phosphorus lowers itself through the heat produced during the attachment of the faceplate and the processing the tube occurs. In some cases @ it is shown that the presence of Potassium silicate in the finished cathodoluminescent screen 27 ensures the adhesion of the adjoining auf @ bracht @ n aluminum film on the screen pattern improved and the luminance of all color-emitting phosphors that make up the screen combination.

Improved A suitable click is also placed on the finished screen Abraaht to form a carrier film with a substantially firmer and smooth surface to build.

The application of the potassium silicate and the varnish on the bemu @ t @ rten Screening can be done in different ways, for example that can Potassium silicate can be applied to the screen when this is still from the pattern development is damp or re-humidified north. After application, the silicate coating is left set and dry, and after that the coated screen becomes uniform with a moistened with an aqueous medium, for example water or a weak alcohol solution in water to # a flawless surface @ for the subsequent application of a leak to obtain. Care must be taken when performing humidification, because a flow of the aqueous medium accidentally part of the potassium silicate protective layer can remove. In another embodiment, the potassium silicate is on Au the dry patterned umbrella as part of the umbrella wetting solution f brought, which is necessary to a flawless surface for application of the leak to be obtained A film of a methacrylate that is essentially free from plasticizers, is then applied to the damp screen, around to bridge the phosphor points and obtain a methacrylate carrier film, which has a substantially firm and smooth surface. The methac has a viscosity in the range of 2.5 to 4.5 centistokes and a methacrylate solids content between 4.6 and 5.0 percent by weight, dissolved in an organic solvent system the at least toluene, xylene, methyl isobutyl ketone, methyl ethyl ketone and / or Contains ethyl acetate.

This type of application of the alkali silicate and varnish is not absolutely necessary, the potassium silicate can also be used as a component of a conventional Emulsion varnish recipe can be applied on a water basis, or it can be used as a separate Layer to be applied before an emulaioaralaek0 After the lacquer film has dried is a thin reflective metal layer such as aluminum Applied to the tight lacquer surface for a smooth and gu reflective To get the back for the color screen.

The viewing plate with the aluminized screen is then at a temperature in the range of substantially 420 to 4400 a for about half an hour Burned long to remove the organic photo sack and lacquer components from the screen remove. Z ¢ Schsttenmsske 31 is then finally back in the front panel 15 is inserted and then the mask-plate assembly is hermetically sealed Frits attached to the funnel part 17 along the end line 16 by the plate and the funnel a connection temperature of about 425 to 465 ° C for about an hour be exposed for a long time. The basic process of tube manufacturing is positioning and sealingly inserting the electron guns into the neck 19 and then working and seal closed.

The finished tube has an improved Dreila @ @@@ cathodoluminescent screen 27 on (Fig 3), the one from a repetier dot pattern of rotan 43, green 45 and blue is: color-emitting components of the specified phosphor combination formed is In the screens treated so that they are sprinkled potassium silicate 49 contained, the greater concentration of the potassium silicate is between the points the Muste @ alemente provided. In certain cases it was determined that the present This potassium silicate layer in the similar screen is responsible for the adhesion of the aluminum film improves and the screen luminance increases It is believed that the precipitate the potassium silicate layer 49 between the screen pattern and the straf arranged metallic reflective layer 51 works in such a way that the light is scattered by the compact points is decreased, so that the reflection effect of the aluminum back film A number of rectangular, 63 cm - 900 - color cathode ray tubes, (RE25AJP22) with faceplates made of glass with about 69% transmission were used with screens the special three-color phosphor combination according to the invention described above One set of tubes had a tight aluminum reflective film over it arranged on a screen in which the green-emitting phosphor is activated with silver Zinc sulfide-cadmium sulfide that had been treated with potassium silicate. Tubes this set were in terms of hue and luminance characteristics compared with other tubes that have the improved phosphorus combinstion without potassium Contained silicate coating and a substantially conforming to the pattern Aluminum reflective film. A further comparison was made with commercially available Pipes carried out with screens, which consisted of: Yttrium-Vanadst activated with europium as red phosphorus, untreated zinc sulfide-cadmium sulfide activated with silver as green phosphorus and common zinc sulfide treated with silver as blue phosphorus, wherein an aluminum reflective film substantially conforming to the pattern is arranged above the screen. Values of the relative leek density of the different Screen types @ were measured under similar conditions, with the phosphors individually and then were stimulated at the same time. With a tension of essentially 25 kV on the screen, each color field was tested for luminance by adding the The corresponding electron probe is set to a beam current of 500 microamps became. After the individual measurements were completed, the three cannons operated at the same time with the respective beam intensities, which are based on a specified Total value, for example 800 μA, were set, EO that a sufficient luminance in each phosphor was evoked to a white of 93000 K: rialten Die unequal electron beam intensities that produce the desired white were measured in microsmpers and in the usual manner in cannon proportions of R / G and R / B compared as benchmarked above. The comparison measurement results are the improved color and luminance properties of the new phosphor system are shown in Table I, to @ smmen with the jet current-gun ratios compiled that are required to generate the 9300 ° K white: New Phosphorus system Improved oxides Common phosphorus-improved oxides less often Soils and System, Regular Va Table I tener Soils and Improved Sulphides nadate rare earth improved sulfides (sil- (silver-activated and regular sulfides, over-activated green) green) three-point screen three-point screen without three-point screen with without potassium silicate potassium silicate, Al film potassium silicate, tight Al film adapted to adapted to pattern Al-film pattern field color total luminous color coordinates Luminous color coordinate - luminous color coordinate radiation density dense naten dense naten electricity (asb) (asb) (asb) (µ A) x y x y x y red 500 127 0.644 0.330 112 0.641 0.329 85 0.644 0.329 green 500 467 0.313 0.589 405 0.325 0.605 409 0.307 0.614 blue 500 100 0.152 0.068 91 0.153 0.067 72 0.151 0.061 Neiss (9300 ° K) 800 418 372 327 Jet current ratio Beam current ratio Beam current ratio for 9300 ° K-White for 9300 ° K-White for 9300 ° K white beam ratios: R / G (800) 0.77 0.66 0.93 R / B (800) 1.21 1.09 1.35 In Fig.5 are the dominant wavelengths of the three phosphorus components of the new Phosphorus combinations shown in relation to the eye sensitivity curve. Obviously the green emission plays a prominent role in the white luminance because the wavelengths of the green part of the spectrum are at the top of the curve, However, green alone does not significantly increase the white luminance level. A strong Improvement of the white luminance density can only be achieved if the epidemic density of all three interacting phosphors is increased or an increase in the Phosphor efficiency of one or more phosphors with a change in chromaticity Another phosphor is combined to increase eye sensitivity for the resulting Knows to effectively raise -Peld.

In Fig. 6 are the moisture densities of the new and improved phosphor system compare graphically with those of the usual system To further the influence of lighter red, green and blue emitting phosphors on the improved white luminance To demonstrate, the respective jet currents are compared, which the 800 zicroampere Total jet flow, with which the 93000 K white is achieved.

Usual umbrella system red cannon (µA) + green cannon (+ A) + blue cannon (µA) = total current 800 gun ratios: R / G = 0.93 G = R / 0.93 R / B = 1.35 B = R / 1.35 R + R / 0.93 + R / 1.35 = 800 red cannon = 285µA = 36% green cannon = 305µA = 38% Blue cannon = 210µA = 26 800µA total current for 9300 ° K @ white; Luminance 327 asb (30.4 FtL) Improved Screen System: (aren activated and treated with Ag; tighter aluminizing gun ratios: R / G = 0.77 G = R / 0.77 R / B = 1.21 B = R / 1.21 R + R / 0.77 + R / 1.21 = 800 red cannon = 256 µA = 32% green cannon = 333 µA = 42% blue cannon = 211 µA = 26% 800 µA total current for 9300 ° K white; Luminance 418 asb (38.8 FtL) The individual jet streams generated by the respective Red, green and RIau guns supplied are components of the total jet stream of 800µA where the size of each current depends on the efficiency of the respective phosphor is fixed.

In the screen phosphor system according to the invention, the excitation requires the improved red-emitting oxide phosphor to achieve better white luminance the desired temperature 256A beam current of the red cannon, compared to about 285µA in the standard system. The improved blue-emitting phosphor provides one higher luminance with approximately the same beam flux. The use of improved red and blue emitting materials allow an additional 28 * A beam current like this to judge that they also have the silver-activated green-emitting phosphorus stimulates, so that a greater luminance is obtained from this component. at the screen according to the invention with an improved phosphor system are approx 42% of the combined beam currents needed to produce a bright white of about 93000 K are required, supplied by the green electron gun.

The invention thus results in a significantly improved * sathodoìumnneezenz screen Made available for a color cathode ray tube of a carefully selected one new combination of phosphors with lighter red and blue emitting materials in conjunction with a special green-emitting phosphor with practically stabilized Has chromaticity coordinates. According to the invention, the screen is treated in such a way that that the luminance characteristics of the new screen combination are improved.

Claims (16)

Expectations Color image @ cathode ray tube with a cathodoluminescent screen, fer has a combination of color-emitting phosphors, characterized in that that the red-emitting phosphorus is an oxide activated with europium of a rare one Earth with white body color is the essentially parallelepiped particle with the property of higher moisture density under electron excitation, the green-emitting end Phosphorus has a characteristic body color that is essentially the same as that of before the tube processing and which lead to a better light density under electron excitation contributes, and the blue-emitting phosphor is so synthesized that it is higher Luminance supplies. 2. Tube according to claim 1, characterized in that the red-emitting Phosphorus gadolinium oxide, yttrium oxide and / or a g dolinium-yttrium mixed oxide where the molar ratios can be represented by the following empirical formula: [(Y1-xGdx) 0.90-0.99Eu0.01-0.10] 2O3 where x is between 0 and 1. 3. Tube according to claim 2, characterized in that the red-emitting Phosphorus is essentially (Y0.940-0.990Eu0.01-0.06) 2O3. 4, tube according to claim 3, characterized in that the C.I.E. color coordinates of the red-emitting phosphor im finished screen are X # 0.644 and y # are 0.330, and that the red-emitting phosphor is a dominant wavelength of about 612 myhat, based on a white of about 93000 K. 5. Tube according to one of claims 1 to 4, characterized in that that the green-emitting phosphor is a zinc-sulfide-cadmium-sulf activated with silver id, the proportion of cadmium sulfide preferably being in the range from 40 to 42 Percentage by weight and the proportion of the @ silver activator about preferably 0.0005 to 0.020 percent by weight. 6. Tube according to claim 5, characterized in that the C.I.E - color coordinates of the green-emitting phosphor in the finished screen are x x # 0.313 and y # 0.590, and that the green-emitting phosphor has a dominant wavelength of about 552 m µ on the basis of a white of about 93000 K. Has. 7 tube according to one of claims 1 to 6, characterized in that that the blue-emitting phosphor is silver activated zinc sulfide, the minor one Inclusions of elements of groups la and 2a of the periodic table as well as aluminum having, wherein the total amount of inclusions is preferably less than about 5% by weight of the total present, silver activated zinc sulfide, 8th tube after Claim 7, characterized in that the inclusions dio the following elements contain: 0.01 to 0.10% by weight of barium, magnesium and / or calcium, 0.01 to 0.10 % By weight of sodium, potassium and / or tiithium, and 0.01 to 1.00% by weight of aluminum, and that the zinc sulfide phosphorus is activated with 0.02 to 0.05% by weight of silver. 9 R @@ re according to one of claims 5 to 8, characterized in that that at least one oxygen-containing compound of N - trium, potassium, lithium and / or Silicon is arranged as an indentation on the screen, with the greater concentration lies between the pattern points. 10. Tube according to one of claims 1 to 9, characterized in that that with an anode voltage of about 25000V and beam currents of 500 microamps the respective red, green and blue pattern fields individually luminescent from huber 110, 410 and 80 asb (11, 41 and 8 ft.L) show, and the luminance that is derived from a total discharge current of 800 microamps at essentially 9300 ° K results in exceeding 370 asb (37 Ft.L). @@ Tube according to claim 10, characterized in that at least 40% of the combined beam currents required to produce a bright white from to produce about 93000 K, to be delivered by the green cannon. 12 tube still one of claims 1 to 11, with a metallic, reflective layer over the cathodoluminescent screen, characterized in, that this layer is arranged smoothly and essentially tautly in such a way that that they are essentially the phosphor particles that make up the screen is bridged. 13 Method of making a three color emitting cathodoluminescent screen for a tube according to claim 12, characterized in that after the development of the third screen pattern, the screen is uniformly moistened with an aqueous medium is, a methacrylate L @ ckfilm is applied with such a viscosity that The phosphor dots are overprinted to form a carrier film with a substantially To get a firm and smooth surface, the paint film is dried, a reflective metal layer is applied to the tight paint surface in order to to get a smooth and well reflective back of the screen, and so on the coated screen is baked to remove the photoresist and the resist film, 80 that the metallic reflective layer remains so that it is the phosphor dots essentially bridged. 14. The method according to claim 13, characterized in that the methacrylate lacquer mixture is essentially free of plasticizers and has a viscosity of has about 2.5 to 4.5 centistokes. 15. Process for the manufacture of a three-color-emitting cathodoluminescent screen for a tube according to claim 5 or 6, characterized in that after developing of the third screen pattern is a 0.01 to 1.0% aqueous solution of at least an oxygen-containing compound of sodium, potassium, lithium and / or silicon is applied to the screen, the screen being moist during application is, and the screen that is noticeable in this way is dried, possibly after a methacrylate paint film is applied to the drying process h 16. Procedure after Claim 15, characterized in that the oxygen-containing compound has a molar ratio of 3.5 parts of silicon dioxide to 1.0 part of potassium oxide contains.