EP0148530B1 - Cathode ray tube - Google Patents
Cathode ray tube Download PDFInfo
- Publication number
- EP0148530B1 EP0148530B1 EP84201897A EP84201897A EP0148530B1 EP 0148530 B1 EP0148530 B1 EP 0148530B1 EP 84201897 A EP84201897 A EP 84201897A EP 84201897 A EP84201897 A EP 84201897A EP 0148530 B1 EP0148530 B1 EP 0148530B1
- Authority
- EP
- European Patent Office
- Prior art keywords
- faceplate
- screen
- cathode ray
- ray tube
- thin film
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired
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Classifications
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01J—ELECTRIC DISCHARGE TUBES OR DISCHARGE LAMPS
- H01J29/00—Details of cathode-ray tubes or of electron-beam tubes of the types covered by group H01J31/00
- H01J29/86—Vessels; Containers; Vacuum locks
- H01J29/89—Optical or photographic arrangements structurally combined or co-operating with the vessel
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01J—ELECTRIC DISCHARGE TUBES OR DISCHARGE LAMPS
- H01J29/00—Details of cathode-ray tubes or of electron-beam tubes of the types covered by group H01J31/00
- H01J29/02—Electrodes; Screens; Mounting, supporting, spacing or insulating thereof
- H01J29/10—Screens on or from which an image or pattern is formed, picked up, converted or stored
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01J—ELECTRIC DISCHARGE TUBES OR DISCHARGE LAMPS
- H01J29/00—Details of cathode-ray tubes or of electron-beam tubes of the types covered by group H01J31/00
- H01J29/02—Electrodes; Screens; Mounting, supporting, spacing or insulating thereof
- H01J29/10—Screens on or from which an image or pattern is formed, picked up, converted or stored
- H01J29/18—Luminescent screens
- H01J29/185—Luminescent screens measures against halo-phenomena
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01J—ELECTRIC DISCHARGE TUBES OR DISCHARGE LAMPS
- H01J2229/00—Details of cathode ray tubes or electron beam tubes
- H01J2229/89—Optical components associated with the vessel
- H01J2229/8907—Image projection devices
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01J—ELECTRIC DISCHARGE TUBES OR DISCHARGE LAMPS
- H01J2229/00—Details of cathode ray tubes or electron beam tubes
- H01J2229/89—Optical components associated with the vessel
- H01J2229/8913—Anti-reflection, anti-glare, viewing angle and contrast improving treatments or devices
- H01J2229/8916—Anti-reflection, anti-glare, viewing angle and contrast improving treatments or devices inside the vessel
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01J—ELECTRIC DISCHARGE TUBES OR DISCHARGE LAMPS
- H01J2229/00—Details of cathode ray tubes or electron beam tubes
- H01J2229/89—Optical components associated with the vessel
- H01J2229/8913—Anti-reflection, anti-glare, viewing angle and contrast improving treatments or devices
- H01J2229/8918—Anti-reflection, anti-glare, viewing angle and contrast improving treatments or devices by using interference effects
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01J—ELECTRIC DISCHARGE TUBES OR DISCHARGE LAMPS
- H01J2229/00—Details of cathode ray tubes or electron beam tubes
- H01J2229/89—Optical components associated with the vessel
- H01J2229/893—Optical components associated with the vessel using lenses
Definitions
- the invention relates to a cathode ray tube having a faceplate arrangement for suppressing halo, said arrangement comprising a faceplate consisting essentially of a transparent material and an internally diposed thin film luminescent screen having an index of refraction larger than that of the faceplate and having opposing surfaces, one of said surfaces being a light scattering surface disposed further from the faceplate than the other, an intermediate thin film layer being disposed between the screen and the faceplate.
- a cathode ray tube is known from US-A-4 132919.
- Cathode ray tubes can be operated at higher electron beam currents, and thus at higher brightness levels, if the conventional powdered layer luminescent screen is replaced with a thin film luminescent screen capable of operating at higher temperatures. This improvement in brightness is offset, however, by the adverse effects of multiple reflections within the thin film screen. Thin film screen cathode ray tubes are especially useful in projection systems because of the high brightness required in these systems.
- cathode ray tubes with a thin film screen are known from GB-A-2 000 173 and also from GB-A-2 024 842.
- U.S.-A-4,310,783 discloses a cathode ray tube faceplate construction including a multilayer absorbing filter disposed between a faceplate and a luminescent screen for reducing halo by attenuating light rays multiply-reflected within the filter, which would otherwise contribute to halo.
- This absorbing filter not only reduces halo, but also useable light.
- the absorption filter is combined with a multilayer layer halo suppressing interference filter disclosed in U.S. Patent 4,310,784.
- This interference filter is angle sensitive to provide low observer side reflectances and high screen side reflectance. Such a combination of a multilayer interference filter on a multilayer absorption filter is overly complicated.
- the cathode ray tube as disclosed at the beginning is characterised in that said intermediate layer has a refractive index smaller than that of the faceplate and a thickness greater than one-half of the wavelength of the light emitted by the luminescent screen.
- Said faceplate arrangement may include according to the invention a multilayer interference filter disposed between the screen and the faceplate, the layers of said interference filter having alternating lower and higher refractive indices, one of said layers being said intermediate thin film layer.
- the objects of the invention are accomplished by providing a faceplate arrangement which not only substantially prevents transmission of light rays that would ordinarily contribute to halo, but which also partially converts these rays to useable light which does not contribute to halo, thereby increasing image brightness and improving contrast.
- Figure 2 graphically depicts as a function of emission angle the distribution of light rays emitted from any excited point on the luminescent screen. This figure illustrates only the principle sources of light transmitted through the faceplate-air interface 28 and ignores the relatively weak rays I' H which are derived from light rays that have been largely transmitted through interface 28.
- the rays I' H do not derive from rays originally emitted at any particular and of angles, but from rays distributed over the entire range of angles outside ⁇ CFA ⁇ CPF are thus dispersed over a large area of the face-plate arrangement, thereby preventing their collective contribution to any localized halo effect. This is not true of the rays I H , however, which are high intensity rays deriving from fully reflected rays emitted in the screen at angles within the well defined band of angles ⁇ CFA ⁇ CPF .
- the light rays emitted from the screen within this band of angles are largely converted to rays I B which are reflected back toward the scattering surface, which radiates part of the rays toward the interface at angles within the useful band of angles 0° -S COL'
- This conversion is effected by disposing between the faceplate and the screen a thin film intermediate layer of a material having an index of refraction which is sufficiently smaller than that of the faceplate to decrease the angle S CPF to a value near that of ⁇ CFA , thereby causing reflection of rays within a band of angles which would otherwise have contributed to halo.
- the refractive index of the intermediate layer should be smaller than that of the screen material.
- the intermediate layer may be provided as the sole layer between the faceplate and the screen or in combination with other layers disposed between the faceplate and the screen.
- the intermediate layer is incorporated as one of the layers of an interference filter, which further improves performance of the faceplate arrangement for a narrow band of wavelengths near the primary emission wavelength of the luminescent screen, by converting a large part of both the rays I H and 1 M to rays Is which are reflected toward the scattering surface.
- This arrangement has the advantage that it can be designed to convert spurious rays having wavelengths outside the narrow band to rays 1 M which totally miss the lens in a projection system, thereby reducing chromatic aberration.
- This amount can be doubled by covering the inner surface of the screen with a highly reflective layer 18 of a material such as aluminum, thereby reflecting light directed toward the vacuum of the tube back toward the faceplate.
- a further increase in the amount of light reaching the lens can be achieved by roughening the inner surface of the screen 16, such as by chemically etching this surface before applying the reflective layer 18.
- the roughened surface 20 serves to scatter light emitted within the screen and reflected from a faceplate-screen interface 21 such that some of this light is redirected toward the interface at angles for which there is less reflection and more light directed toward the lens.
- the reflective layer 18 and the scattering surface 20 not only increase the amount of useful light reaching the lens 12, however, they also increase light contributing to halo surrounding the image of the electron beam spot focussed by the lens.
- FIG. 1 shows a plurality of light rays emitted at different angles from a point 22 in a spot excited by an electron beam 24. All angles are measured relative to a line 26 originating at point 22 and passing perpendicularly through the faceplate-screen interface 21 and a faceplate-air interface 28. All light rays emitted toward the interface 21 are at least partly reflected back toward the scattering surface 20 as rays Is, where they are scattered and redirected toward the interface. Light rays emitted at angles equal to or greater than the critical angle ⁇ CPF for total internal reflection from the interface 21 are totally reflected to the scattering surface 20.
- Part of this light is redirected toward the interface 21 at an angle less than ⁇ CPF and passes through the interface.
- the lateral shift between point 22 and the point at which the reflected rays impinge on the scattering surface 20 are typically on the order of the thickness of the thin film screen 16 (e.g. 1-3 mm) and thus does not substantially increase the diameter of the luminscent electron beam spot, which is typically about 100 ⁇ .
- the light rays emitted from point 22 which pass through the faceplate-screen interface 21 reach the faceplate-air interface 28.
- Portions I L of these rays, emitted from point 22 at angles between 0° and ⁇ COL pass through interface 28 and are collected by lens 12.
- Portions 1 M emitted from point 22 at angles between ⁇ COL and ⁇ CFA (the critical angle for the face-plate-air interface) totally miss the lens and are lost within the system.
- a portion I H or I' H of each ray reaching the interface 28 is reflected, passes through or is reflected by interface 21, and eventually returns to and passes through interface 28.
- the lateral shifts between the point 22 and the points at which the rays I H and I' H eventually pass through the interface 21 are on the order of the faceplate thickness (e.g. 2-5 millimeters). These laterally-shifted rays form a number of concentric ringshaped halos around the image of the electron beam spot, causing a decrease in image contrast.
- FIG. 3 illustrates a first embodiment of a cathode ray tube faceplate arrangement including a thin film halo suppression layer in accordance with the invention.
- the face plate arrangement 30 includes the same faceplate 14, thin film screen 16, reflective layer 18 and scattering surface 20 as the arrangement in Figure 1, but further includes a thin film layer 32 disposed between the faceplate and the screen.
- the thickness of the intermediate layer 32 must be greater than one-half the wavelength of the light emitted by the screen to prevent interference effects and should be substantially smaller than the diameter of the luminescent spot produced by the electron beam.
- the exemplary arrangement shown in Figure 3 will reduce halo intensity by a factor of three and increase image brightness by a factor of two.
- FIG 4 illustrates a second embodiment of a cathode ray tube faceplate arrangement in which a thin film halo suppression layer in accordance with the invention is incorporated into an interference filter.
- the faceplate arrangement 40 includes the same faceplate 14, thin film screen 16, reflective layer 18 and scattering surface 20 as the arrangement in Figure 3, but the halo suppression layer 42 also serves as a low refractive index layer in the multilayer interference filter 44 which has alternating low and high refractive indices.
- the halo suppression layer 42 need n6t be disposed on the thin film screen 16 itself, as is shown, but may serve as any one of the low refractive index layers in the filter 44.
- a ray diagram is not presented in Figure 4 because of the difficulty in illustrating the operation of the interference filter, but the angles illustrated in Figure 3 would be identical in the Figure 4 embodiment.
- Both the thickness and the refractive index of the halo suppression layer 42 will be determined by the same criteria as for the Figure 3 embodiment.
- the refractive indices of the remaining layers in the interference filter 44 are not critical, but the difference between the refractive indices of any two adjacent layers should be as large as possible to maximize the reflection of rays originating from point 22 at angles between ⁇ COL and ⁇ CPF .
- the thickness of the layers in the filter 44 are very important and are determined by use of conventional techniques such as those described in Born and Wolf, Principles of Optics, Pergamon Press, 6th edition, 1980.
- the thicknesses of the layers are selected to provide a pass band centered around the primary wavelength of luminescent light emitted by the screen 16.
- An exemplary, 8 layer interference filter has been designed for use in a face plate arrangement, such as that of Figure 4, having a primary emission wavelength of 544 nm (5440 A) and refractive indices and thickness as listed in Table 2.
- the layers are listed in order of successive distance from the screen 16, with layer A corresponding to the halo suppression layer 42.
Landscapes
- Cathode-Ray Tubes And Fluorescent Screens For Display (AREA)
- Vessels, Lead-In Wires, Accessory Apparatuses For Cathode-Ray Tubes (AREA)
- Transforming Electric Information Into Light Information (AREA)
Description
- The invention relates to a cathode ray tube having a faceplate arrangement for suppressing halo, said arrangement comprising a faceplate consisting essentially of a transparent material and an internally diposed thin film luminescent screen having an index of refraction larger than that of the faceplate and having opposing surfaces, one of said surfaces being a light scattering surface disposed further from the faceplate than the other, an intermediate thin film layer being disposed between the screen and the faceplate. Such a cathode ray tube is known from US-A-4 132919.
- Cathode ray tubes can be operated at higher electron beam currents, and thus at higher brightness levels, if the conventional powdered layer luminescent screen is replaced with a thin film luminescent screen capable of operating at higher temperatures. This improvement in brightness is offset, however, by the adverse effects of multiple reflections within the thin film screen. Thin film screen cathode ray tubes are especially useful in projection systems because of the high brightness required in these systems.
- Other cathode ray tubes with a thin film screen are known from GB-A-2 000 173 and also from GB-A-2 024 842.
- U.S.-A-4,310,783 discloses a cathode ray tube faceplate construction including a multilayer absorbing filter disposed between a faceplate and a luminescent screen for reducing halo by attenuating light rays multiply-reflected within the filter, which would otherwise contribute to halo. This absorbing filter not only reduces halo, but also useable light. In an alternative embodiment disclosed in the patent, the absorption filter is combined with a multilayer layer halo suppressing interference filter disclosed in U.S. Patent 4,310,784. This interference filter is angle sensitive to provide low observer side reflectances and high screen side reflectance. Such a combination of a multilayer interference filter on a multilayer absorption filter is overly complicated.
- It is an object of the invention to provide a simple cathode ray tube faceplate arrangement which effective suppresses halo.
- It is another object of the invention to provide such a faceplate arrangement which suppresses halo without substantially reducing luminescent light which does not contribute to halo.
- According to the invention the cathode ray tube as disclosed at the beginning is characterised in that said intermediate layer has a refractive index smaller than that of the faceplate and a thickness greater than one-half of the wavelength of the light emitted by the luminescent screen.
- Said faceplate arrangement may include according to the invention a multilayer interference filter disposed between the screen and the faceplate, the layers of said interference filter having alternating lower and higher refractive indices, one of said layers being said intermediate thin film layer.
- The objects of the invention are accomplished by providing a faceplate arrangement which not only substantially prevents transmission of light rays that would ordinarily contribute to halo, but which also partially converts these rays to useable light which does not contribute to halo, thereby increasing image brightness and improving contrast. The manner in which this is accomplished can be best understood by referring to Figure 2 which graphically depicts as a function of emission angle the distribution of light rays emitted from any excited point on the luminescent screen. This figure illustrates only the principle sources of light transmitted through the faceplate-
air interface 28 and ignores the relatively weak rays I'H which are derived from light rays that have been largely transmitted throughinterface 28. Further, the rays I'H do not derive from rays originally emitted at any particular and of angles, but from rays distributed over the entire range of angles outside ⊖CFA ―⊖CPF are thus dispersed over a large area of the face-plate arrangement, thereby preventing their collective contribution to any localized halo effect. This is not true of the rays IH, however, which are high intensity rays deriving from fully reflected rays emitted in the screen at angles within the well defined band of angles ⊖CFA―⊖CPF. In accordance with the invention, the light rays emitted from the screen within this band of angles are largely converted to rays IB which are reflected back toward the scattering surface, which radiates part of the rays toward the interface at angles within the useful band of angles 0° -SCOL' This conversion is effected by disposing between the faceplate and the screen a thin film intermediate layer of a material having an index of refraction which is sufficiently smaller than that of the faceplate to decrease the angle SCPF to a value near that of ⊖CFA, thereby causing reflection of rays within a band of angles which would otherwise have contributed to halo. The refractive index of the intermediate layer should be smaller than that of the screen material. - The intermediate layer may be provided as the sole layer between the faceplate and the screen or in combination with other layers disposed between the faceplate and the screen. In one embodiment the intermediate layer is incorporated as one of the layers of an interference filter, which further improves performance of the faceplate arrangement for a narrow band of wavelengths near the primary emission wavelength of the luminescent screen, by converting a large part of both the rays IH and 1M to rays Is which are reflected toward the scattering surface. This arrangement has the advantage that it can be designed to convert spurious rays having wavelengths outside the narrow band to rays 1M which totally miss the lens in a projection system, thereby reducing chromatic aberration.
- The present invention will now be described by way of example with reference to the accompanying drawings, in which:
- Figure 1 is a sectional view of one end of a cathode ray tube faceplate and a lens in a projection system employing a prior art cathode ray tube;
- Figure 2 is a schematic diagram showing the angular distribution of light rays emitted from the cathode ray tube screen in the system of Figure 1;
- Figure 3 is a sectional view of one end of a cathode ray tube faceplate and a lens in a projection system employing a first embodiment of a cathode ray tube in accordance with the invention.; and
- Figure 4 is a sectional view of one end of a cathode ray tube faceplate and a lens in a projection system employing a second embodiment of a cathode ray tube in accordance with the invention. The multiple reflections are illustrated in Figure 1, which depicts part of a cathode ray tube projection system including the right end of a cathode ray tube
face plate arrangement 10 spaced from a focusinglens 12, both shown in cross-section. Thelens 12 magnifies an image formed by light rays received from thefaceplate arrangement 10 and projects the image onto a relatively large reflective or transmissive screen (not shown). Thearrangement 10 included afaceplate 14 made of a material having good thermal conductivity, such as sapphire, and a thin filmluminescent screen 16 deposited onto the faceplate. Typical thickness for the face plate and the screen, which are not drawn to scale, are 2-5 millimeters and 1-3 µm, respectively. - Although Figure 1 is not drawn to scale, it demonstrates conceptually the effects of multiple reflections within the thin film luminescent screen. Because the refractive indices of luminescent screen materials are higher than those of conventionally used faceplate materials, a very small percentage of light emitted by the excited screen succeeds in reaching the
lens 12. For example, in a projection cathode ray tube having asapphire faceplate 14 with a refractive index n, = 1.8 and a thinf filmluminescent screen 16 with a refractive index np = 2.3, the amount of emitted light actually leaving the faceplate was determined to be less than 5%. This amount can be doubled by covering the inner surface of the screen with a highlyreflective layer 18 of a material such as aluminum, thereby reflecting light directed toward the vacuum of the tube back toward the faceplate. A further increase in the amount of light reaching the lens can be achieved by roughening the inner surface of thescreen 16, such as by chemically etching this surface before applying thereflective layer 18. The roughenedsurface 20 serves to scatter light emitted within the screen and reflected from a faceplate-screen interface 21 such that some of this light is redirected toward the interface at angles for which there is less reflection and more light directed toward the lens. - The
reflective layer 18 and thescattering surface 20 not only increase the amount of useful light reaching thelens 12, however, they also increase light contributing to halo surrounding the image of the electron beam spot focussed by the lens. - The manner is which light rays emitted by the luminescent screen are transmitted through the
faceplate arrangement 10 can be best understood by referring to Figure 1 which shows a plurality of light rays emitted at different angles from apoint 22 in a spot excited by anelectron beam 24. All angles are measured relative to aline 26 originating atpoint 22 and passing perpendicularly through the faceplate-screen interface 21 and a faceplate-air interface 28. All light rays emitted toward theinterface 21 are at least partly reflected back toward thescattering surface 20 as rays Is, where they are scattered and redirected toward the interface. Light rays emitted at angles equal to or greater than the critical angle ⊖CPF for total internal reflection from theinterface 21 are totally reflected to thescattering surface 20. Part of this light is redirected toward theinterface 21 at an angle less than ⊖ CPF and passes through the interface. The lateral shift betweenpoint 22 and the point at which the reflected rays impinge on the scatteringsurface 20 are typically on the order of the thickness of the thin film screen 16 (e.g. 1-3 mm) and thus does not substantially increase the diameter of the luminscent electron beam spot, which is typically about 100 µ. - The light rays emitted from
point 22 which pass through the faceplate-screen interface 21 reach the faceplate-air interface 28. Portions IL of these rays, emitted frompoint 22 at angles between 0° and θCOL pass throughinterface 28 and are collected bylens 12. Portions 1M emitted frompoint 22 at angles between θCOL and θCFA (the critical angle for the face-plate-air interface) totally miss the lens and are lost within the system. A portion IH or I'H of each ray reaching theinterface 28 is reflected, passes through or is reflected byinterface 21, and eventually returns to and passes throughinterface 28. The lateral shifts between thepoint 22 and the points at which the rays IH and I'H eventually pass through theinterface 21 are on the order of the faceplate thickness (e.g. 2-5 millimeters). These laterally-shifted rays form a number of concentric ringshaped halos around the image of the electron beam spot, causing a decrease in image contrast. - Figure 3 illustrates a first embodiment of a cathode ray tube faceplate arrangement including a thin film halo suppression layer in accordance with the invention. The
face plate arrangement 30 includes thesame faceplate 14,thin film screen 16,reflective layer 18 and scatteringsurface 20 as the arrangement in Figure 1, but further includes athin film layer 32 disposed between the faceplate and the screen. Thelayer 32 consists essentially of MgF2 having a refractive index nM = 1.38, which substantially decreases the angle θCPF from that of the prior art Figure 1 embodiment. This is demonstrated by Table 1 which lists the angles θCFA and θCPF for the Figure 1 and Figure 3 embodiments. The smaller band of angles lying between θCPF and θCFA is also apparent from the rays shown in Figure 3. - According to the invention, the thickness of the
intermediate layer 32 must be greater than one-half the wavelength of the light emitted by the screen to prevent interference effects and should be substantially smaller than the diameter of the luminescent spot produced by the electron beam. For an intermediate layer thickness of 0.8 pm it has been determined that the exemplary arrangement shown in Figure 3 will reduce halo intensity by a factor of three and increase image brightness by a factor of two. - Figure 4 illustrates a second embodiment of a cathode ray tube faceplate arrangement in which a thin film halo suppression layer in accordance with the invention is incorporated into an interference filter. The faceplate arrangement 40 includes the
same faceplate 14,thin film screen 16,reflective layer 18 and scatteringsurface 20 as the arrangement in Figure 3, but thehalo suppression layer 42 also serves as a low refractive index layer in themultilayer interference filter 44 which has alternating low and high refractive indices. Thehalo suppression layer 42 need n6t be disposed on thethin film screen 16 itself, as is shown, but may serve as any one of the low refractive index layers in thefilter 44. A ray diagram is not presented in Figure 4 because of the difficulty in illustrating the operation of the interference filter, but the angles illustrated in Figure 3 would be identical in the Figure 4 embodiment. - Both the thickness and the refractive index of the
halo suppression layer 42 will be determined by the same criteria as for the Figure 3 embodiment. The refractive indices of the remaining layers in theinterference filter 44 are not critical, but the difference between the refractive indices of any two adjacent layers should be as large as possible to maximize the reflection of rays originating frompoint 22 at angles between θCOL and θCPF. The thickness of the layers in thefilter 44 are very important and are determined by use of conventional techniques such as those described in Born and Wolf, Principles of Optics, Pergamon Press, 6th edition, 1980. The thicknesses of the layers are selected to provide a pass band centered around the primary wavelength of luminescent light emitted by thescreen 16. - An exemplary, 8 layer interference filter has been designed for use in a face plate arrangement, such as that of Figure 4, having a primary emission wavelength of 544 nm (5440 A) and refractive indices and thickness as listed in Table 2. The layers are listed in order of successive distance from the
screen 16, with layer A corresponding to thehalo suppression layer 42. The materials used for this filter are M8F2(nm = 1.38) and ZnS (nz = 2.3).
Claims (2)
Applications Claiming Priority (2)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
US56568383A | 1983-12-27 | 1983-12-27 | |
US565683 | 1983-12-27 |
Publications (2)
Publication Number | Publication Date |
---|---|
EP0148530A1 EP0148530A1 (en) | 1985-07-17 |
EP0148530B1 true EP0148530B1 (en) | 1988-03-02 |
Family
ID=24259674
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
EP84201897A Expired EP0148530B1 (en) | 1983-12-27 | 1984-12-18 | Cathode ray tube |
Country Status (6)
Country | Link |
---|---|
EP (1) | EP0148530B1 (en) |
JP (1) | JPS60157143A (en) |
KR (1) | KR850004342A (en) |
CA (1) | CA1221725A (en) |
DE (1) | DE3469639D1 (en) |
ES (1) | ES8602298A1 (en) |
Family Cites Families (2)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US4132919A (en) * | 1977-12-12 | 1979-01-02 | Lockheed Missiles & Space Company, Inc. | Absorbing inhomogeneous film for high contrast display devices |
US4263061A (en) * | 1978-03-27 | 1981-04-21 | Minnesota Mining And Manufacturing Company | Process for forming a high resolution X-ray intensifying screen with antireflecting substrate |
-
1984
- 1984-12-18 EP EP84201897A patent/EP0148530B1/en not_active Expired
- 1984-12-18 DE DE8484201897T patent/DE3469639D1/en not_active Expired
- 1984-12-20 CA CA000470630A patent/CA1221725A/en not_active Expired
- 1984-12-24 KR KR1019840008312A patent/KR850004342A/en not_active Application Discontinuation
- 1984-12-24 ES ES539027A patent/ES8602298A1/en not_active Expired
- 1984-12-24 JP JP59272734A patent/JPS60157143A/en active Pending
Also Published As
Publication number | Publication date |
---|---|
DE3469639D1 (en) | 1988-04-07 |
ES539027A0 (en) | 1985-11-16 |
ES8602298A1 (en) | 1985-11-16 |
EP0148530A1 (en) | 1985-07-17 |
KR850004342A (en) | 1985-07-11 |
CA1221725A (en) | 1987-05-12 |
JPS60157143A (en) | 1985-08-17 |
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