MXPA99003251A - Method and apparatus for manufacturing a color crt - Google Patents

Abstract

A method for manufacturing a color CRT (10) having a faceplate panel (12) includes the steps of forming a photoreceptor (36) on an interior surface of a viewing faceplate (17);establishing a substantially uniform electrostatic charge on the photoreceptor (36);and exposing selected areas of the photoreceptor (36) to visible light to form a latent charge image. The process further includes the steps of developing the latent charge image on the photoreceptor (36) by depositing (212, 213, 214) thereon charged phosphor particles;monitoring the width (218) of the deposition of the charged phosphor particles;and terminating the deposition (226, 227, 228) of the charged phosphor particles when predetermined process parameters (222, 224) are satisfied. Also, a phosphor deposition monitor (PDM) apparatus (90) for monitoring the deposition of the charged phosphor particles on the latent charge image, formed on the photoreceptor (36), includes monitoring means (96, 99, 123) external to the viewing faceplate (17) for measuring the width (218) of the deposition of the charged phosphor particles. Control means (122) responsive to the monitoring means (96, 99, 123) is utilized for terminating the deposition (226, 228) of the charged phosphor particles when the predetermined process parameters (222, 224) are satisfied.

Description

METHOD AND APPARATUS FOR MANUFACTURING A CATHODIC COLOR RAYS TUBE The invention relates to a method and apparatus for making a color cathode ray tube using a deposit of charged phosphor particles and, more particularly, to a method and apparatus. to monitor the width of the resulting elements of the phosphor screen deposited in the openings in a light absorption matrix provided on an interior surface of a front viewing plate of the cathode ray tube. BACKGROUND OF THE INVENTION An apparatus for developing a latent charge image on a photoreceptor that is placed on an interior surface of a viewing face plate of a deployment device, such as a cathode ray tube (CRT), using charged particles. triboelectrically, it is described in U.S. Patent No. 5,477,285, issued December 19, 1995, to GHN Riddle and co-inventors. The deposition of each of the three different color emitting phosphors is controlled by detecting a voltage, proportional to the charge of the triboelectrically charged phosphor particles deposited in a latent charge image formed in a photoreceptor, and monitoring this voltage to stop the deposition of the phosphor particles when the voltage reaches a predetermined value corresponding to a specific thickness of the phosphorus. The shielding process of electrostatic phosphorus, which uses dry powdered materials, is unique in that phosphorus deposits are formed from the center outwards during the deposition or revelation process. Thus, the thickness of the resulting phosphorus lines is not uniform and is routed from the center of the lines to the edges. A disadvantage of the voltage measurement approach is that, in addition to their thicknesses, the phosphor lines must also be of sufficient width to completely fill the openings in the die that has been provided on the inner surface of the face plate panel of the tube. cathode rays. The voltage detection developed by triboelectrically deposited phosphor particles does not provide an indication of the width of the phosphor line. If gaps occur between the sides of the phosphor lines and the light absorption matrix, it is determined that the quality of the screen is not satisfactory and the resulting brightness is not optimized. Therefore, it is desirable not only to monitor the voltage developed by the deposition of charged phosphor particles, but also to determine the width of the phosphorus lines as the phosphorus reveals. BRIEF DESCRIPTION OF THE INVENTION In accordance with the present invention, there is disclosed a method of making a color cathode ray tube having a faceplate panel. The method includes the steps of forming a photoreceptor on an interior surface of a viewing area of the faceplate panel; establishing an electrostatic charge substantially one iforme in the photoreceptor; and exposing selected areas of the photoreceptor to visible light to form a latent charge image. The process also includes the steps of revealing the latent charge image in the photoreceptor depositing phosphorus particles loaded therein; monitor the width of the deposition of charged phosphor particles; and finish the deposition of charged phosphor particles if predetermined process parameters are met. Also disclosed is a phosphor deposition monitor (PDM) apparatus for monitoring the deposition of charged phosphor particles in the latent charge image formed in the photoreceptor. The phosphor deposition monitor apparatus includes monitoring means external to the viewing face plate to measure the deposition width of the charged phosphor particles. The control means that respond to the monitoring means are used to finish the deposition of the charged phosphor particles if predetermined parameters of the process are met. BRIEF DESCRIPTION OF THE DRAWINGS In the accompanying drawings: Figure 1 is a plan view, partially in axial section, of a color cathode ray tube made in accordance with the present invention; Figure 2 is a section of a faceplate panel with a die on an inner surface thereof; Figure 3 is a section of the tube screen assembly shown in Figure 1; Figures 4 and 5 show, respectively, a front view and a top view of a novel phosphor deposition monitor (PDM) apparatus for measuring the width of a phosphor deposit; Figures 6 and 7 show, respectively, a top view and a side view of an image forming device used in the phosphor deposition monitor apparatus of Figures 4 and 5; Figures 8, 9 and 10 show phosphor line profiles for three phosphor development scenarios; and Figure 11 is a flow chart showing the steps of the process in the present invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT Figure 1 shows a color cathode ray tube 10 having a glass envelope 1 1 comprising a rectangular faceplate panel 12 and a tubular neck 14 connected by a rectangular funnel 15. Funnel 15 it has an internal conductive coating (not shown) that contacts an anode button 16 and extends into the neck 14. The panel 12 comprises a front viewing plate 17 and a peripheral flange or side wall 18, which is sealed to the funnel 15 by a glass frit 19. As shown in Figure 2, a relatively thin light absorbing matrix 20, having a plurality of openings 21, is provided on the inner surface of the viewing faceplate 17. A three-color luminescent phosphor screen 22 is on the inner surface of the faceplate 17 and is placed on the die 20. The display 22, shown in Figure 3, is preferably a a line screen which includes a multiplicity of screen elements formed of red, blue, and green emitting phosphor strips, R, A, and V, centered on matrix openings other than matrix openings 21 and arranged in groups of color or image elements of three stripes or triads, in a cyclic order. The fringes extend in a direction which is generally normal to the plane in which the electron beams are generated. In the normal viewing position of the modality, the phosphorus bands extend vertically. Preferably, portions of the phosphor strips overlap at least a portion of the light absorbing matrix 20 surrounding the openings 21. A dot screen can also be formed through the novel process. A thin conductive layer 24, preferably aluminum, is superimposed on the screen 22 and provides means for applying a uniform potential to the screen as well as for reflecting the light, emitted from the phosphor elements, through the front plate 17. The screen 22 and superimposed aluminum layer 24 comprise a screen assembly. Again with reference to Figure 1, a multi-aperture color selection electrode, such as a shadow mask or focus mask, is removably mounted by conventional means, in predetermined spaced relation to the screen assembly. The color selection electrode 25 is removably attached to a plurality of bolts 26 embedded in the side wall 1 8 of the panel 12. An electron gun 27, shown schematically by the interrupted lines, is centrally mounted in the the neck 14, to generate and direct three electron beams 28, along convergent paths, through the openings in the color selection electrode 25, to the screen 22. The electron gun is conventional and can be any suitable barrel known in the art. The tube 10 is designed to be used with an external magnetic deflection yoke, such as the yoke 30, placed in the region of the funnel-neck joint. When activated, the yoke 30 submits the three beams 28 to magnetic fields that cause the beams to scan horizontally and vertically, in a rectangular frame, on the screen 22. The initial plane of deflection (in zero deflection) is shown by the line P- P in Figure 1, approximately half of the yoke 30. Simplification does not show the actual curvatures of the trajectories of deflection beams in the deflection zone. The screen 22 is manufactured by an electrophotographic (EPS) shielding process which is described in United States Patent Serial Number 4,921, 767, issued to Datta and co-inventors on May 1, 1990. Initially, the Panel 12 is cleaned by washing with a caustic solution, rinsed in water, etched with hydrofluoric acid stabilizer and rinsed again with water, as is known in the art.

Then, the light absorbing matrix 20 is preferably provided to the interior surface of the viewing face plate 17 using, preferably, the conventional wet-matrix process described in US Pat. No. 3,558,310, issued to Mayaud. on January 26, 1971. In the wet matrix process, a suitable photoresist solution is applied to the interior surface, for example, by centrifugal coating, and the solution is dried to form a photoresist layer. Then, the color selection electrode 25 is inserted into the panel 12 and the panel is placed in a three-in-one beacon (not shown) which exposes the photoresist layer to actinic radiation from a light source that projects light through the the openings in the color selection electrode. The exposure is repeated twice more with the light source placed to simulate the trajectories of the electron beams from the three electron guns. The light selectively alters the solubility of the exposed areas of the photoresist layer. After the third exposure, the panel is removed from the headlight and the color selection electrode is removed from the panel. The photoresist layer is developed using water to remove the most soluble areas thereof, thereby exposing the underlying inner surface of the viewing face plate, and leaving the less soluble exposed areas of the photoresist layer intact. Then, a suitable solution of light absorbing material is uniformly provided on the inner surface of the faceplate panel to cover the exposed portion of the vision faceplate and the less soluble retained areas of the photoresist layer. The layer of light absorbing material is dried and developed using a suitable solution which will dissolve and remove the retained portion of the photoresist layer and the light absorbing material on lay, forming openings 21 in the layer of the matrix 20, which is adhered to the interior surface of the front faceplate. For a panel 12 to have a diagonal dimension of 51 cm (20 inches), the openings 21 formed in the matrix 20 have a width of 0.13 to 0.18 mm, and the opaque matrix lines have a width of approximately 0.1 to 0.15 mm. Then, the inner surface of the viewing faceplate 17, which has the matrix 20 therein, is coated with a suitable layer of a volatilizable organic conductive (OC) material, not shown, which provides an electrode for a photoconductive layer organic (OPC) volatile superimposed, also not shown. The organic conductive layer and the organic photoconductive layer, in combination, comprises a photoreceptor 36, shown in Figure 4. Suitable materials for the organic conductive layer include certain quaternary ammonium polyelectrolytes described in the U.S. Patent Serial Number 5,370,952, issued to P. Datta and co-inventors on December 6, 1994. Preferably, the organic photoconductive layer is formed by coating the organic conductive layer with a solution containing polystyrene; an electron donor material, such as 1,4-di (2,4-methyl phenyl) -1,4-diphenylbutatriene (2,4-DMPBT); electron-receiving materials, such as 2,4,7-trinitro-9-fluorenone (TNF) and 2-ethylanthraquinone (2-EAQ); and a suitable solvent, such as toluene, xylene, or a mixture of toluene and xylene. A surfactant, such as silicone U-7602 and a plasticizer, such as dioctyl phthalate (DOP), can also be added to the solution. Surfactant U-7602 is available from Union Carbide, Danbury, CT. The photoreceptor 36 is charged in a uniformly electrostatic manner using a corona discharge device (not shown), described in United States Patent No. Serial No. 5,083,959, issued on January 28, 1992, to Datta and co-inventors, which charges the photoreceptor 36 to a voltage in the range of about +200 to +700 volts. Then the color selection electrode 25 is inserted into the panel 12, which is placed in a headlight (also not shown) and the positively charged organic photoconductive layer of the photoreceptor 36 is exposed, through the color selection electrode 25, to the light of a xenon flashlight or other light source of sufficient intensity , such as arc of mercury, arranged in the lighthouse. The light passing through the openings in the color selection electrode 25, at an angle identical to that of the electron beams of the tube electron gun, discharges the illuminated areas in the photoreceptor 36 and forms a latent charge image. . The color selection electrode 25 is removed from the panel 12 and the panel is placed in a first phosphor developer 40, such as that shown in Figure 4. The developer 40 comprises a developing chamber 42 having a lower end 44 and a upper end or panel support 46. The panel support 46 is preferably formed of insulating material and includes an opening 48 therethrough which is slightly smaller in dimensions than the front plate panel of the cathode ray tube 12. panel 12 is supported on the panel support 46. The developing chamber 42 further includes an outer side wall 50 and extends from an inner conductive bottom end 54 to a plane A-A adjacent to the panel support 46. The conductive side wall 52 and the lower end 54 attract excess phosphorus from the charged phosphorus cloud, preventing an accumulation of space charge in chamber 42, or a high electrostatic potential in the side wall l of the camera. A space 56, positioned at the upper periphery of the chamber 42, between the outer and inner side walls 50 and 52, provides a path for removing excess phosphor particles that are not deposited in the latent charge image formed on the photoreceptor 36. An exhaust port 58 is connected to a pump (not shown) to remove excess phosphor particles from the developer 40. An electrical contact, such as a pin contact spring 60 is provided to contact one of the bolts 26 embedded in the side wall 18 of the faceplate panel 12. The conductive coating of the photoreceptor 36 is electrically connected by a contact patch (not shown) to the bolt 26. The contact patch is described in U.S. Pat. from North America Serial Number 5, 156,770, issued to Wetzel and co-inventors on October 20, 1992. The electrical contact 60 is connected and grounded through of a capacitor 64 that develops a voltage proportional to the charge of the triboelectrically charged phosphor particles deposited in the latent charge image in the photoreceptor 36. The voltage developed in the capacitor 64 is monitored by an electrometer 66 and is connected to a controller 68 which is programmed to teate the phosphor deposition when the voltage reaches a predeteed value corresponding to the required phosphor thickness. Before each development cycle, the voltage in the capacitor 64 is discharged to ground through a contact 70, by the action of the controller 68. A high voltage source 72 is connected to a developing grid 74 to control the electric field in the vicinity of the latent charge image formed in the photoreceptor 36. The structure and function of the developing grid 74 are described in United States Patent Serial No. 5,093,217, issued March 3, 1992, to Datta and co-inventors. The grid 74 is positively polarized at about 3kV and has the same polarity as that of the triboelectrically charged phosphor particles that are being deposited in the latent charge image. A separate developer 40 is required for each of the three color emitting phosphors, to avoid cross-contamination which would otherwise occur if a single developer were used and different color-emitting phosphor materials were fed into a common chamber. External to the developing camera 42 is a phosphor deposit 76, which contains a supply of dried phosphorus powder particles. During the developing operation, the phosphor particles are transported from the tank 76 to a venturi chamber 78 where the phosphor particles are mixed with a suitable amount of air. The actuation of the air supply is achieved by opening a valve 80 controlled by the controller 68. A pressure regulator 82 establishes the air pressure. The phosphor particles are carried to the chamber 42 and through a triboelectric barrel 84, where the phosphor particles are positively and triboelectrically charged and are directed towards the latent charge image in the photoreceptor 36. The phosphorus particles emitting the first positively charged colors are repelled by the positively charged areas in the photoreceptor 36 and are deposited in the areas discharged therefrom by the process known in the art as "reverse" developing. In reverse development, the triboelectrically charged phosphor particles of the material of the screen structure are repelled by similarly charged areas of the photoreceptor 36 and are deposited in the areas discharged therefrom. The phosphorus lines of the emitter phosphor of the first color are deposited in selected openings of the openings 21 in the matrix 20 and accumulate in width and height from the center of the openings 21 to the edges of the surrounding matrix. When the deposition is complete, it is necessary that the phosphor lines be slightly larger than the openings 21 in the light absorption matrix 20, as shown in Figure 3, to completely fill each of the openings and slightly overlap the matrix absorption of light surrounding the openings. With reference to Figures 4 and 5, a novel phosphor deposition monitor apparatus 90, includes a support assembly having a pair of side rails 92 and 93 that are mounted to the support surface 46 of the developer 40, adjacent to the opening 48. The side rail 92 and 93 are sufficiently spaced apart to allow a front panel panel 12 to be placed on the support surface 46 without interference from the side rails. A first pair of cross rails 94 and 95 are slidably attached to the cross rails 94 and 95. A second pair of cross rails 97 and 98 are also slidably attached to the side rails 92 and 93 and support a second cross-over device. image formation 99 which is slidably connected to the second pair of cross rails 97 and 98. Imaging devices 96 and 99 are mounted about 15 cm (6 inches) above the viewing face plate. Each of the imaging devices 96 and 99 moves in the x-yy plane and can be tilted to be substantially parallel to the curvature of the viewing face plate 17. Additionally, the imaging devices 96 and 99 are they can be placed anywhere above the viewing faceplate 17. As shown in Figure 5, one of the imaging devices 96 and 99, e.g., the device 99, is usually positioned near the center of the panel 12. while the other imaging device 96 is adjacent to the periphery of the panel. The side rails 92 and 93 are sufficiently long to allow the imaging devices 96 and 99 to be removed from above the opening 48 to facilitate placing and removing the faceplate panels 12 of the developer 40. The imaging device 96, shown in Figures 6 and 7, includes a support structure 100 comprising a main body portion 102 and two opposite disposed end portions 104 and 106, which are attached to the main body portion 102. A mounting bracket 107 is attached to each end portion 104 and 106 to facilitate assembly of imaging devices 96 and 99, on the appropriate cross rails 94, 95 and 97, 98. A support bracket 108 and a motor 1 10 are secured to the main body portion 102, in spaced relationship therebetween. A motor shaft 112 extends from the motor 1 10 and is attached to a camera 1 14 to move the camera on the support bracket 108, in a plane parallel to the main body portion 102. An objective lens 116 is attached to the camera 1 14. To minimize the height of the imaging device 96 and not to interfere with the panel transfer equipment, not shown, a 45 degree angle mirror, shown in Figure 7, is used to bend the optical path . If the height of the imaging devices 96 and 99 is not critical, then the mirror 118 is not required and the imaging devices can be mounted vertically. The motor 1 10 moves the entire camera / lens assembly instead of just the objective lens 1 16, to focus the camera 1 14 on the phosphor lines comprising the screen elements. This focusing configuration provides a constant magnification for any focus position, thus improving the accuracy of line width measurements. A coaxial fiber optic light ring 120 is placed below the mirror 1 18 to provide uniform glow-free illumination of the object to be observed. The electrical connections to the motor 1 10, the camera 1 14 and the light ring 120 are conventional and therefore not shown. Again with reference to Figures 4 and 5, an image processor 122, such as a personal computer having a video monitor 123, is connected to the cameras of the first and second imaging devices 96 and 99 for storing and display line width data and form the images of the triads comprising an arbitrarily defined measurement window, such as a window 124, shown in Figure 5, on the front view plate 17. The video monitor 123 of the processor Images 122 shows the width of the phosphor lines during the deposition process. The deposition is complete when the phosphor completely fills the openings 21 in the matrix 20 and at least partially overlaps the light absorbing material of the matrix 20 surrounding the openings 21.

During the deposition of the phosphorus emitter of the first color, the phosphorus deposition accumulates from the center of the openings 21 towards the edge of the matrix 20, as shown by the monotonic drop and increase at the edges of the phosphor profile in the Figure 8. In Figure 8, the matrix lines 20 are designated "M", the emitting phosphor of the first color is designated P1 and the matrix openings, 21. Under the matrix and phosphorus is the photoreceptor 36 and the inner surface of the front panel panel 12. When viewed on monitor 123, the matrix lines appear black and the openings between the adjacent matrix lines, where the phosphors are to be deposited, appear dark and less pronounced than the matrix lines. The present sequence of phosphorus deposition provides that the phosphorus emitter of the first color, P1, deposited in the photoreceptor, is the phosphorus emitter of blue. In Figure 8, phosphor P1 does not completely fill aperture 21 to show phosphorus during deposition by the EPS process. However, the deposition continues until the openings 21, in which the first phosphorus is deposited, are filled and preferably, there is an overlap of the matrix 20, as shown in Figure 3. The output of each of the devices of image formation 96 and 99 is fed to the image processor 122, so that the line width data is updated approximately twice every second. The line width data can be used with values of elapsed time or electrostatic charge and its proportional voltage, measured in sample panels that are used to establish calibration values, so that a smooth growth function can be coupled for width of line to the accumulated data. As it is not possible to visually measure the line width growth after filling the openings 21, the calibration, elapsed time and / or electrostatic charge values obtained in sample panels are used to determine the cut-off time for the deposition of phosphorus in production panels. After the deposition of the first phosphor is complete, the panel 12 is removed from the phosphor developer 40 and transferred to the corona discharge apparatus, described above, where it is electrostatically charged. The recharge restores a positive voltage in the photoreceptor 36 and in the phosphor material of the first color, P1, deposited therein. The steps of light exposure and phosphor development are repeated for each of the phosphors emitting the two remaining colors, P2 and P3. When the panel 12 is placed in the second and third phosphor developers 40, the imaging devices 96 and 99 form the image of the phosphor lines deposited above and act as inspection devices to allow the completion of the deposition process if Previous phosphorus deposits are not recorded correctly or are otherwise unacceptable. As shown in Figures 9 and 10, the size of each of the lines of the emitting phosphors of the two remaining colors, P2 and P3, in the photoreceptor 36 is also larger than the size of the matrix openings 21, for ensure that no spaces occur and provide a slight overlap of the light absorption matrix "M" surrounding the openings. The interaction between the phosphor deposition monitor apparatus 90 and the phosphor developer 40 is shown in Figure 11. The faceplate panel 12 with the matrix 20 and the photoreceptor 36 therein are charged to the panel holder 46 in the process step 200. The imaging devices 96 and 99, which contain cameras 1 14, are positioned above the faceplate panel 12, one camera in the vicinity of the center of the faceplate 17 and the other in a location near the edge of the panel, in process step 202. When the cameras are in position, a communications signal 203 is sent to the phosphor deposition monitor 90 to determine if the cameras are in place. The placement of the cameras is determined in step 204. When it is determined that the cameras are in place, the cameras are focused on the step 206 and the measurement window 124 on the viewing face plate 17 is defined in step 208. At this point in the operation, a ready camera signal 209 is sent to the developer 40. If determines that the phosphor deposition monitor 90 is ready in step 210, the developer 40 initiates the deposition of the first phosphor in step 212. A communications signal 213 is sent from the developer 40 to the phosphor deposition monitor 90 to determine if deposition has begun in step 214. When deposition of the first tribo-charged phosphorus is initiated, the charge deposited in the photoreceptor is read by the electrometer 66 and the elapsed time is recorded by the phosphor deposition monitor, as indicated in step 216. The imaging devices 96 and 99 are used in conjunction with suitable computer programs so that the image processor 122 measures the width of the phosphor lines, and any displacement thereof, in the appropriate matrix openings 21, of the measurement window 124, as indicated in step 218, as the phosphor deposition continues in step 220. The parameters of the process of accumulated charge, elapsed time and phosphor width are compared with the established limits, as indicated in step 222, and if the limits have not been exceeded, a communications signal 223 is sent to phosphor 40, where in step 224, it is determined if the process limit or the maximum deposition time has been exceeded. If the process limit or the maximum deposition time has not been exceeded, the phosphor deposition is continued. However, if the process limit or the maximum deposition time has been exceeded, the deposition is stopped, as indicated in step 226, and a communications signal 227 is sent to the phosphor deposition monitor 90, as indicated. in step 228. When the deposition is stopped, the process data is analyzed in step 230 and recorded in step 232. At this time the cameras are removed from above the front panel 12, as indicated in step 234 , and a communications signal 235 is sent, to determine the camera positions, to the phosphor deposition monitor 90, in step 236. Then, the faceplate panel 12 is discharged in step 238 and the deposition monitor phosphor 90 is restarted, in step 240, by sending initialization signals 241 and 242 to ensure that the cameras are ready and that process limitations are set, respectively, for the next panel. The panel 12 having the first phosphor, P1, is electrostatically charged and the color selection electrode 25 is placed back in it. Then, the panel 12 is placed in a headlight, not shown, where the photoreceptor 36 is exposed to light in the areas where the second phosphor will be deposited, P2. The color selection electrode is removed from the panel 12 and the panel is transferred to a second developer 40 for the deposition of the emitter phosphor of the second color, P2. The process is repeated, again the phosphorus emitter of the third color, P3. Each of the phosphor developers 40 has a phosphor deposition monitor 90 associated therewith for monitoring line width data for each of the phosphors.

Claims (10)

1. REVIVAL NAMES 1. A method for making a color cathode ray tube (10) having a front panel panel (12) with a light absorbing matrix (20) disposed on an inner surface thereof, said matrix having a plurality of openings (21) therein, said method includes the steps of: forming a photoreceptor (36) superimposed on said matrix; establishing a substantially uniform electrostatic charge in said photoreceptor; exposing selected areas of said photoreceptor to visible light to affect the charge therein, without affecting the charge in the unexposed area of such photoreceptor, thereby forming a latent charge image to reveal the said latent charge image in such photoreceptor depositing (212). , 213, 214) phosphorus particles loaded therein; externally monitoring the width (218) of the deposition of charged phosphor particles through the openings in said matrix; and generate a control signal to complete the deposition (226, 227, 228) of the charged phosphor particles when predetermined process parameters are met (222, 224).
2. 2. A phosphor deposition monitor apparatus (P DM) (90) for monitoring the width (218) of the deposition of the charged phosphor particles in the latent charge image, formed in a photoreceptor (36) superimposing a matrix of light absorption (20) having a plurality of openings (21) therein, said matrix is disposed on an inner surface of a front viewing plate (17) of a cathode ray tube front plate panel (12). ), including a monitoring device (96, 99, 123) external to said viewing face plate to measure the width (218) of the phosphor lines formed in the openings of such matrix due to the deposition of the phosphor particles charged, and a control device (122) responsive to said monitoring device of such a phosphor deposition monitor apparatus, to generate a control signal (227) to complete the deposition (226, 228) of the charged phosphorus particles. as when predetermined process parameters (222, 224) are met.
3. 3. An apparatus for depositing and monitoring the deposition of triboelectrically charged phosphor particles in an electrostatic latent charge image formed in a photoreceptor (36) disposed in a matrix (20) having a plurality of openings (21) therein, said matrix superimposes an inner surface of a front viewing plate (17) of a cathode ray tube front plate panel (12), said apparatus comprises a phosphor developer (40) having a developing chamber (42) with a panel support (46) for supporting such a faceplate panel, said chamber provides triboelectrically charged phosphor particles to reveal such a latent charge image in said photoreceptor, an electrical contact (60) connected to said photoreceptor, a first monitoring device, including an electrometer (66) connected through a capacitor (64) to such electrical contact, to measure the amount of charge that is being deposited in such a latent charge image by the triboelectrically charged phosphor particles: comprising a second monitoring device, including a imaging device (96, 99) external to said viewing faceplate, an image processor (122) and a video monitor (123) for forming the deposition image of the triboelectrically charged phosphor particles in such an image of latent load, such a video monitor being connected to such imaging device to facilitate the deployment of a measurement window (124) in said viewing face plate; and such first and second monitoring devices generate a control signal (227) to complete the deposition (226.228) of the triboelectrically charged phosphor particles when predetermined process parameters are met (222)., 224).
4. 4. An apparatus for depositing and monitoring the deposition of triboelectrically charged phosphor particles in an electrostatic latent charge image formed in a photoreceptor (36) disposed in a matrix (20) having a plurality of openings (21) therein, said matrix is on an interior surface of a front viewing plate (17) of a cathode ray tube front plate panel (12), said apparatus comprises a phosphor developer (40) having a developed camera (42) with a panel support (46) for supporting such a front panel, said chamber further includes means (84) p triboelectrically charging the phosphor particles and an aperture (48) in such a panel support to allow tribo-charged phosphor particles pass through such an image latent charge in said photoreceptor, an electrical contact (60) connected to said photoreceptor, a first monitoring means (66) connected to such electrical contactor , to measure the amount of charge that is deposited in such a latent charge image by phosphorus particles triboelectrically charged; comprising a phosphor deposition monitor apparatus (90) including second monitoring means (96, 99) external to said cold viewing plate, for measuring the size of the image elements formed by the deposition of the phosphorus particles triboelectrically charged in such a latent charge image; and control means (122) responding to such first monitoring means and said second monitoring means, to generate a control signal (227) to complete the deposition (226,228) of phosphorus particles charged triboelectrically when they meet predetermined parameters of the process ( 222, 224).
5. The apparatus described in claim 4, wherein the monitoring means comprises an image forming device (96, 99) separated from an outer surface of said viewing face plate (17) to view a measurement window (124). ) on such a viewing face plate, and an image processor (122) having a video monitor (123) connected to such an image forming device to display said measurement window.
6. The apparatus described in claim 5, wherein said imaging device (96, 99) includes a support structure (100) comprising a main body portion (102) and two end portions arranged in an opposite manner. (104, 106) attached to said main body portion, a support bracket (108) and a motor (1 10) are secured to such a main body portion, a motor shaft (12) extends from said motor. and is attached to a camera (1 14) having a target lens (1 16) attached thereto, said motor moves said camera and objective lens in a plane parallel to said main body portion to focus said camera to form in images such screen elements in said objective lens.
7. The apparatus described in claim 6, further including an inclined mirror (118) spaced apart from said objective lens (16) and a glow-free light source (120) disposed between said inclined mirror and such screen elements.
8. 8. The apparatus described in claim 7, wherein said glow-free light source (120) and is a coaxial fiber optic light ring (120) and said mirror (18) is inclined at an angle of 45 °. degrees.
9. 9. The apparatus described in claim 4, wherein said control means comprises a series of periodic phosphor line width measurements made during the deposition of such phosphor particles in said photoreceptor (36), such line width measurements of phosphorus are compared to a desired line width value. The apparatus described in claim 4, wherein said control means further comprises a predetermined calibration value of line width versus deposited charge, the amount of charge measured by such an electrometer (66) is used to regulate the deposition time. by reference to the predetermined calibration value. eleven . The apparatus described in claim 4, wherein said control means comprises a visual measurement of phosphor line width in such a video monitor (123).