US3899994A

US3899994A - Apparatus for application of lacquer coating to cathode ray tube panels

Info

Publication number: US3899994A
Application number: US438964A
Authority: US
Inventors: Charles A Cook; Thaddeus J Hajduk
Original assignee: Zenith Radio Corp
Current assignee: Zenith Electronics LLC
Priority date: 1972-12-29
Filing date: 1974-02-04
Publication date: 1975-08-19
Anticipated expiration: 1992-08-19

Abstract

This disclosure depicts improved method and apparatus for automatically processing front panels of cathode ray tubes in a continuous step-by-step fashion including spraying a lacquer coating onto a phosphor coating on the panels. The front panels are loaded in a front-side-up attitude onto an annular endless conveyor which is stepped around a plurality of discrete work stations disposed around the perimeter of the conveyor, each of the work stations being adapted to perform at least one predetermined operation on the panels. Lacquer applicator means is situated in at least one of said work stations for applying a lacquer coating on the panels. Enclosure means are provided for enclosing the lacquer applicator and associated drying stations to prevent escape of lacquer vapors to the environment. Vertically movable shroud means are provided at the lacquer application station for enshrouding the panels during the lacquer applying operation to minimize air currents which might disturb the surface of the wet lacquer coating.

Description

United States Patent Cook et a1. Aug. 19, 1975 1 APPARATUS FOR APPLICATION OF 3,319,556 5/1967 Fiore 96/36.] x LACQUER COATING o CATHODE RAY 3,440,081 4/1969 Glovatsky et a1. 1 18/321 X 3,741,149 6/1973 Gerlovich 118/326 X TUBE PANELS [75] Inventors: Charles A. Cook, Buffalo Grove; Primary Examinepnlohn p McIntosh Tfhaddeus Hajduk, Chicago both Attorney, Agent, or Firm-John H. Moore 0 Ill. 0

[731 Assignee: Zenith Radio Corporation, Chicago, ABSTRACT This disclosure depicts improved method and appara- [22] Filed; 4 1974 tus for automatically processing front panels 01 cathode ray tubes in a contlnuous step-by-step fashlon 1nl 1 PP 3 cluding spraying a lacquer coating onto a phosphor Related Application Data fcoating don the panegjs. The front panels are lgladed in a .[62] Division Of Ser. N6. 319,970, D66. 29, 1972, Pat. No, rom'sl eTup.atmu e an en 3,832,211 veyor which is stepped around a plurality of discrete work stations dlsposed around the per1meter of the 52 us. c1. 118/6; 1 18/56; 118/73; Conveyor each of the Work Stations being {idapted 118/318 1 18/319 118/326 perform at least one predetermmed operation on the [5 I 1 Int Cl 2 BOSC 7/02 panels. Lacquer applicator means is situated in at least 58 1 Field of Search 118/319, 73, 318, 322, P of f a for applying F 118/326, 52, 56, 6, 634, 320; 117 33 (3, 33 mg t e il f f? i f z 3 CP 33 CM; 96/361; 134/177 enclosing the acquer app lcator an dSSOCldIe rymg statlons to prevent escape of lacquer vapors to the en- [561 Refem'ces Cited lii' li ti;21131121123231?)5113111321":$5131 UNITED STATES PATENTS ing the panels during the lacquer applying operation 2-426-39l 8/1947 Emerson H8/3l9 X to minimize air currents which might disturb the sur- 2,723,2()6 ll/l955 Falk 118/319 X face of the wet lacquer Coating 2,792,810 5/1957 Maconeghy et a1. 118/55 X 2,941,499 6/1960 Gutzmer 118/52 X 14 Claims, 4 Drawing Figures /fl/%r -i- I mz/wm/ zwmw/w' ##9##- I 1 1 1. 1'1 1 6 e4 1 e4 66 I L 1 |1.

X T J PQTENTED AUG'] 9 I975 SHEET 1 OF 3 TEU AUG! 91975 III I'I ii iii" To :Lclcquer" Ill I'll Eli: 5 I'll N APPARATUS FOR APPLICATION OF LACQUER COATING TO CATHODE RAY TUBE PANELS CROSS REFERENCE TO RELATED APPLICATIONS This application is a division of a co-pending application Ser. No. 319,970, filed Dec. 29, 1972, now US. Pat. No. 3,832,211, entitled Improved Method and Apparatus for Application of Lacquer Coating to Cathode Ray Tube Panels, assigned to the assignee of this invention.

BACKGROUND OF THE INVENTION The present invention pertains to the manufacture of color cathode ray tubes of the shadow mask type presently in commerical use in color television receivers. It is specifically directed toward apparatus and method for processing and applying a lacquer coating to the phosphor coated side of the front panels of such tubes.

A picture tube can be thought of as consisting of two separate units, each manufactured and processed separately, which are united to form a completed picture tube. The first unit is the front panel assembly which consists of the glass front panel, the aperture (shadow) mask, and the steel frame which supports and positions the shadow mask within the front panel.

The second unit consists of a funnel-shaped glass envelope containing the electron gun assembly in the neck of the envelope. The manufacturing process of interest herein applies only to the front panel unit; the discussion below will therefore be limited and directed toward that aspect of the manufacture of a color picture tube.

One part of the tube production operation involves depositing three superimposed layers of phosphor material. One well-known process for applying the phosphor layers is referred to as slurry screening. In practicing that process, a slurry coating of photosensitive re sist and one of the three color phosphors is applied over the screen area of the front panel. After the coating had dried, it is exposed to actinic light which is directed through the shadow mask of the tube in process. As a consequence of this exposure, elemental areas of the slurry coating are rendered insoluble and the pattern thus formed is developed by washing the exposed screen with a solvent to remove the unexposed portions of the coating. The exposed insoluble areas which remain constitute the elements (the dots) of the particular color associated with that slurry coating. This procedure is followed for each of the three colors with appropriate adjustment in position of the exposing actinic light source for each phosphor, so that the color phosphor dots are properly arranged in triads.

Upon completion of the screening process, a thin lacquer coating is applied to the entire surface of the front panel. This lacquer coating serves to cover and fill in the area between the triad phosphor elements in order to provide a smooth surface for the application ofa thin aluminum coating thereon. The aluminum coating serves, inter alia, to reflect light emitted by illuminated phosphor dots toward the front of the panel to effectively increase the brightness of a reproduced image as seen by a television viewer.

Before this invention, this lacquer coating operation has been a time consuming and inefficient partially manual operation having an unsatisfactory yield factor. Because of the volatile nature of the lacquer vapors which are generated during this step of the process, it has been found necessary to isolate the lacquer application apparatus from the apparatus associated with other steps of the tube manufacturing operation. In so doing, each panel has required substantial manual handling in transporting the panels to the isolated area. The need to isolate the lacquer applicating apparatus has until now created a bottleneck in the processing of cathode ray tube panels.

As a result of this bottleneck in color cathode ray tube manufacturing operations and the relatively low yield factors from the lacquer applying operation, due to handling and nonuniform quality of the applied lac quer coatings, the cost of the end product tubes has been unnecessarily high. Further, prior art lacquerapplying processes require that manual operations be performed in the unpleasant lacquer environment.

OBJECTS OF THE INVENTION Accordingly, it is a general object of this invention to provide improved apparatus for applying a lacquer coating to phosphor coatings on front panels of color cathode ray tubes.

It is a more specific object to provide improved appa ratus for applying such lacquer coatings which is fully automated and which enables the lacquer-applying operation to be performed on a continuous basis and in line with other tube panel processing operations.

It is another object to provide improve lacquerapplying apparatus which are faster than prior art methods and apparatus, which produces more uniform coatings, and which have substantially higher yield factors.

It is still another object to provide cathode ray tube lacquering apparatus which does not require human contact with a vaporous lacquer environment.

BRIEF DESCRIPTION OF THE DRAWINGS The features of this invention which are believed to be new are set forth with particularity in the appended claims. The invention, together with further objects and advantages thereof, may be best understood by reference to the following description in conjunction with the accompanying drawings in which like numbers refer to like elements and in which:

FIG. 1 is a side view, partially broken away, of cathode ray tube processing apparatus embodying the subject invention;

FIG. 2 is a sectional plan view, in part schematic, taken along the line 22 in FIG. 1, but with certain internal components removed to more clearly illustrated the invention.

FIG. 3 is an enlarged, partially sectional view of a protion of the FIG. 2 apparatus; and

FIG. 4 is a table indicating the timing of certain operations performed by the FIG. 2 apparatus.

DESCRIPTION OF THE PREFERRED EMBODIMENT As briefly described above, the processes associated with the manufacture of cathode ray tube front panels includes depositing phosphor and photoresist materials in slurry form on the back side of the panels. The phosphor deposit is then exposed and developed in a manner well known in the art in order to generate a matrix of phosphor dots of one color in accordance with a predetermined dot pattern. The process of depositing the slurry on the front panel is known as screening Apparatus for automatically performing such a screening process is depicted in US. Pat. No. 3,319,759, issued to T. J. I-Iajduk et al., assigned to the assignee of this invention. The apparatus described therein rapidly applies a uniform phosphor coating to the cathode ray tube panels with a minimum of manual handling. The panels are then screened, exposed and developed in the same manner for the other two phosphor colors to generate the well known red-blue-green dot triad phosphor pattern.

The next step in the process is the application of a lacquer coating over the phosphors. This operation, in applicants knowledge, had never been implemented in a way'which allowed the entire processing operation to proceed at a satisfactory rate, at least not with any degree of uniformity in the finished panels. One requirement of the lacquer application process which tended to slow down the entire panel processing operation was the need to isolate the lacquer application apparatus from the rest of the panel processing machinery to insure that any lacquer vapors generated would be confined to a relatively small area in order to minimize the potential fire harzard. This need for isolation further aggravated the already relatively slow lacquerapplication process by requiring that the phosphor coated panels be transported from the phosphor screening area to the lacquer application area.

Another aspect of panel processing which, until now, further slowed the production of cathode ray tubes was the necessity of first drying a panel which had been previously screened, exposed and developed with all three phosphor colors before the process of applying a lacquer coating could being. Now, in accordance with this invention, because of the way in which the panel processing environment is controlled during the panel processing steps, a panel need not be first dried before receiving its lacquer coating. The elimination of the drying step permits each panel to be processed even faster. The steps taken to preserve a suitable environment for the speedier processing of the panels will be detailed in the discussion below.

In the description to follow, it will be shown how the adaptation of existing apparatus to the special requirements of the lacquer application process can result in a vastly improved method and apparatus for processing and applying the lacquer coating to a cathode ray tube panel.

Referring now to FIG. 1, there is shown, partly in schematic form, a side view of apparatus for processing color picture tube panels in accordance with the principles of this invention. As shown clearly in FIG. 2, the apparatus is generally circular. The apparatus comprises an endless annular conveyor which defines a circular processing path. Fifteen discrete work stations, labelled A-O, are equally spaced around the perimeter of conveyor 10, at each of which at least one processing operation takes place. The processing steps which occur at each work station will be detailed below after an overall description of the apparatus has been given.

Although the preferred embodiment of the invention is shown in FIGS. 1 and 2 as being circular, it is contemplated that other embodiments thereof may have different shapes. An important aspect of this invention is that the panel processing operations take place in a continuous, closed loop-type fashion in order to provide a controlled atmosphere for the processing steps which are described below. The rotary apparatus shown inFIGS. 1 and 2 is well suited for such processing.

Attached to conveyor 10 are workpiece holders 12 which move with conveyor 10 from one work station to another in a step-by-step fashion.

The step-by-step movement of conveyor 10 is controlled by indexing means 13 which may be a conven tional timer. Indexing means 13 is shown in FIG. 1 as being mounted on the outer housing 20 of the apparatus, but itmay also be situated at any convenient remote location.

Each workpiece holder 12 is mechanically coupled to a rotatable panel support 14 which is adapted to carry a picture tube panel 16 through each processing step. Note that every panel 16 is supported front side up so that its phosphor coated surface is directed downwardly toward the washing devices, lacquer application devices, etc. which are positioned beneath the panel positions at the several work stations.

Important advantages in processing the panels with their front sides up will be pointed out below when a more detailed description of the lacquer application process is given.

Mounted on each workpiece holder 12 is a motor 18 coupled to each panel support 14 for spinning each panel support and its associated panel at predetermined speeds in order to facilitate the processing operations at each station. The speed of each motor is dependent on the work station at which its supporting workpiece is situated. Switches (not shown in FIG. 2) are mounted on brackets attached to-conveyor l0 and situated to come into contact with actuating cams (also not shown in FIG. 2) positioned at each work station. By varying the position of the cams at the several work station, one or more selected speed control switches may be actuated to cause a motor 18 to run at a predetermined speed. The switches and cams will be dis cussed and pointed out in the description to follow.

The components of the apparatus are confined within a housing 20 and supported by a base 22. Housing 20 is fitted with an enclosure 21 for enclosing work stations F-J which contain the lacquer application stations and associated drying stations. By enclosing those stations, volatile lacquer vapors which may be present are prevented from escaping to the environment.

In operation, a panel 16 is loaded at station A where there is preferably a loading and unloading device 23 (not shown in detail) such as that described in US. Pat. No. 3,856,129 assigned to the assignee of this invention. Upon a signal generated by indexing means 13, conveyor 10 moves counterclockwise until each workpiece holder is advanced to the next successive work station.

Prior to being loaded on this apparatus, each panel has received three phosphor coatings, the first two of which have been exposed and developed in a manner well known and practiced in the art. The last phosphor coating will have been exposed to actinic light for rendering insoluble its respective array of dots, stripes, or in whatever geometric pattern the phosphor coating are arranged. For purposes of this invention, it is immaterial in what geometric pattern the phosphors are deposited. The panel is then loaded onto the FIG. 2 apparatus. Upon advancement to station B, the last received phosphor coating is developed by rinsing the downwardly facing phosphor coated surface with a suitable solvent to remove unexposed phosphor particles. A liquid caustic solution is then applied to the phosphor coated surface to further dissolve and remove unexposed phosphor particles. One advantage of the process and apparatus according to this invention in which each panel is maintained in a front-side-up attitude is that any excess rinse water, solvents, dissolved particles or lacquer may more easily drop way from the panels. During the rinse, panel 16 is spun at a predetermined speed, preferably at about 7.5 rpm, in order to facilitate the developing process.

In response to a signal from indexing means 13, convey--r advances panel 16 to work station C where the panel 16 is further developed and washed. At this point, the panel remains spinning at about 7.5 rpm.

Work station D includes apparatus for further rinsing each panel, scrubbing the outer skirt of each panel with brushes (not shown) and spraying a prewet solution onto the downwardly exposed surface of each panel. The prewet solution may be of any suitable type such as a water, polyvinyl alcohol, and potassium silicate combination which will provide a suitable liquid foundation for the subequent application of a lacquer coating. At station D, the panel continues to spin at about 7.5 rpm.

At station E, panel 16 is spun at about 65 rpm to level off the prewet while receiving an air blast to facilitate drying. Stations F and G are also drying stations at which the panel 16 continues to spin at about 65 rpm.

Work station H is the location at which each panel receives a lacquer coating. Details of the lacquer application assembly are shown in FIG. 3 and will be more thoroughly discussed below after a brief description of each of the processing stations has been completed. After a panel 16 has been positioned at work station H, a shroud 26 having an open upper end is positioned around the panel 16. Positioned below panel 16 at work station H is a spray applicator assembly 28 which sprays the lacquer coating directly onto the downwardly exposed phosphor coated surface of the panel. Shroud 26 surrounds spray applicator 28 and when the panel above is ready to receive the lacquer spray, shroud 26 is vertically displaced so that it encloses, at least partially, both spray application 28 and panel 16. Thus enclosed within shroud 26, panel 16 is shielded from undesirable air currents during the lacquer application process which might otherwise cause unwanted distrubances on the lacquer coating. During the application of the lacquer spray, panel 16 is spun at 140 rpm to insure a uniform distribution of lacquer. When the spray cycle is complete, shroud 26 is lowered away from panel 16.

At work stations I and J, each panel is spun at about 130 rpm to level off and make uniform the previously applied lacquer coating.

At station K, the rotational speed of each panel is reduced to about 7.5 rpm. This lower speed is continued at station L where there is applied a blast of hot air to assist the drying of the lacquer coating. At station M, spray nozzles (not shown) are situated beneath the panel in process for spraying a material on the underside of each panel effective to eliminate the formation of blisters when the panel is heated and baked in subsequent processing. Hot air is then directed at the panel while it continues to spin about 7.5 rpm.

Stations N and O are both drying stations at which the panels in process continue to spin at about 7.5 rpm while they are dried by the application of hot air. The dried panel is then advanced to station A where it is unloaded.

The total processing time for each panel is about six minutes from loading to unloading. The table shown in FIG. 4 indicates how much time is allotted to each processing step at each of the 15 work stations. With only 24 seconds allocated to each work station, panels are processed at the rate of 150 per hour. This rate is a factor of 2 to 4 times greater than the speeds at which panels may be processed and lacquered by known prior art methods. An important advantage in practicing this invention is that the speed at which each panel is processed by the method and apparatus described herein is comparable with the speeds at which phosphor screening machines operate. The panels may be indexed from station to station at the same rate at which they are indexed from station to station in the three associated phosphor screening machines. The lacquer application apparatus described herein and the three phosphor screening machines may therefore all be indexed by a central timer. This will enable all four machines to proceed at the same speed and will reduce bottlenecks which result from one processing step being substantially slower than the others.

Referring to FIG. 3, a more detailed description will be given of the apparatus and method used at station H to apply the lacquer coating. As shown, panel 16 is in position to receive the lacquer coating. By means of motor 30, gear reducer 32 and cam lifter 34, shroud 26 and its supporting assembly 36 are driven upward to the elevated position as shown. Base 38 is vertically displaced until its lip 40 engages limit switch 42 which deactivates motor 30. Upon completion of the lacquer application cycle at station H, motor 30 lowers shroud 26 and its entire supporting assembly until lip 40 engages lower limit switch 44; switch 44 in turn deactivates motor 30. Excess lacquer drains from shroud 26 through drain 47 and is collected in a pan 49.

Note that panel support 14 includes overhanging members 46 which, along with the upward extending elements 48, enclose panel 16 within the housing 50 at station H. When panel support 14 is in its proper position at station H,

elements

46 and 48 are positioned relative to one another as shown so as to partially seal and confine lacquer vapors within housing 50. Similar housings 50 are situated at stations F, G, I and J to further assist in the confinement of the lacquer vapors. Housing 50 and elements 46 also serve to preserve Within their boundaries an atmosphere which is suitable for the processes at the several work stations. The sealing of the selected work stations is made easier because of the fact that the panels 16 remain in a frontside-up attitude throughout the entire processing operation. The same sealing method can then be used at each work station, if desired.

Panel support 14 also includes extending members 51 which, when shroud 26 is in its elevated position as shown in FIG. 3, assist in confining the lacquer and its vapor within shroud 26.

Spray applicator 28 preferably includes two spray nozzles 52 for applying a uniform lacquer coating to the panel. The lacquer is supplied to spray nozzles 52 via a flexible hose 54 which is connected to a source of lacquer (not shown).

Panel 16 and its support 14 are spun at about rpm by means of motor 18 and connecting assembly 58. As mentioned briefly above, switches are mounted on each workpiece holder and situated so as to contact actuating cams positioned at each work station. These switches 60 and the earns 62 associated with work station H are schematically shown in FIG. 3. The cams 62 are positioned differently in each of the several work stations and serve as preprogrammed control means to cause each motor 18 to run at a predetermined speed at each work station.

workpiece holder 12 also supports hanger 64. The mask frame assembly 66 associated with each front panel 16 hangs from hanger 64 as shown in FIG. 3. By keeping each mask frame assembly 66 with its panel 16 throughout the process, the chance of a mask being matched to the wrong panel is minmized.

Thus, it is apparent that there has been provided, in accordance with the invention, an improved color picture tube processing and lacquer application method and apparatus that fully satisfies the objects as set forth above. While the invention has been described in conjunction with specific embodiments thereof, it is evident that many alterations, modifications and variations will be apparent to those skilled in the art in the light of the foregoing invention. Accordingly, it is intended to embrace all such alternations, modifications and variations which fall within the spirit and scope of the appended claims.

We claim:

1. Rotary apparatus for automatically applying a lacquer coating over a phosphor coating on partially processed front panels of cathode ray tubes in a continuous step-by-step fashion while said panels are continuously maintained in a front-side-up attitude so that the phosphor coated surfaces of said panels are continuously directed downwardly, comprising:

an annular endless conveyor defining a predetermined processing path;

a plurality of workpiece holding means serially attached to said conveyor for each receiving and supporting a panel front side up such that the phosphor coated surface of said panel is directed downwardly during its processing;

a plurality of discrete work stations disposed around the perimeter of said conveyor for receiving said workpiece holding means and panels;

indexing means for effecting step-by-step movement of said conveyor between said work stations;

spray applicator means situated on at least one of said work stations for spraying a lacquer coating onto the downwardly directed phosphor coating of a received panel;

moveable shroud means situated at the work station at which the lacquer coating is applied and means for positioning said shroud means over a panel to be coated in order to minimize undesirable air currents which might cause unwanted distrubances on the surface of the lacquer coating and to help contain lacquer vapors within the lacquer application work station;

drying means situated at at least one of said work stations for drying said lacquer coating; and

loading and unloading means for receiving panels to be conveyed to a first of said work stations and for presenting for removal lacquered panels conveyed from a final work station.

2. The apparatus as defined in claim 1 including stationary enclosure means for enclosing said applicator means and associated drying stations so as to contain and separate said applicator means and associated drying stations from the external environment, thereby preventing lacquer vapors from escaping to the environment.

3. The apparatus as defined in claim 1 wherein selected work stations include a preprogrammed control means and wherein each workpiece holding means is provided with both a rotatable support for receiving a panel and a motor coupled to said support for spinning said support and its panel at predetermined intervals and speeds in response to said control means.

4. Rotary apparatus for automatically applying a lacquer coating over a phosphor coating on front panel areas of cathode ray tubes in a continuous step-by-step fashion, comprising:

an annular endless conveyor disposed along a predetermined processing path;

a plurality of workpiece holding means serially attached to said conveyor;

a rotatable panel support on each of said workpiece holding means for receiving and supporting a panel during its processing;

spray applicator means situated at at least one of said work stations for spraying a lacquer coating into a received panel;

movable shroud means having an open end and means for moving said shroud means vertically such that said shroud means at least partially surrounds said panel only during the process of lacquer application to minimize undesirable air currents which might cause unwanted disturbances on the surface of the lacquer coating;

t. enclosure means enclosing said spray applicator means and associated drying stations and so disposed as to contain and separate said spray applicator means and said associated drying stations from the external enviroment, thereby preventing lacquer vapors from escaping from the area immediately surrounding said spray applicator means and associated drying station;

a motor mounted on each of said workpiece holding means and coupled to the panel thereon for rotating said support and its associated panel;

preprogrammed control means situated at selected work stations for controlling the operation of said motor in order to spin said supports and panels at predetermined intervals and speeds; and

5. The apparatus as defined in claim 4 wherein said work stations include at least one developing station in advance of the station which contains the applicator means for receiving panels whose last phosphor coating is undeveloped, said developing station being adapted to develop said last exposed phosphor dots by rinsing said panel with a solvent to remove unexposed phosphor particles.

6. The apparatus as defined in claim 5 wherein said developing station is followed by at least one washing station adapted to wash said panels prior to the application of the lacquer coating.

7. The apparatus as defined in claim 4 wherein said work stations include at least one drying station at which each panel is exposed to preheated forced air after having received a lacquer coating.

8. The apparatus as defined in claim 4 wherein each of said panel supports carries a first sealing means, and

the spray applicator station and said associated drying stations each include a second sealing means, said first and second sealing means cooperating to at least partially seal a received panel within said spray applicator station and said associated drying stations, thereby containing lacquer vapors within the respective work staions.

9. Rotary apparatus for automatically processing and applying a lacquer coating over a phosphor coating on front panel areas of cathode ray tubes in a continuous step-by-step manner, comprising:

an annular endless conveyor defining a predetermined processing path;

a plurality of workpiece holding means serially at tached to said conveyor;

a plurality of discrete work stations disposed around the perimeter of said conveyor for receiving said workpiece holding means and panels, each of said work stations being particularly adapted to perform at least one predetermined operation on said panels;

indexing means for effecting step-by-ste'p movement of said conveyor between said work stations;

developing means, situated at a first work station for receiving panels whose last phosphor coating is undeveloped and for developing said last phosphor coating by rinsing said panel with a solvent to remove unexposed phosphor particles;

washing means situated at a second work station following said developing means for washing each panel as it arrives at said second work station;

spray applicator means situtated at a third one of said work stations for spraying a lacquer coating on each received panel;

movable shroud means having an open end, and means for moving said shroud means vertically such that said shroud means at least partially surrounds said panel only during the porcess of lacquer application to minimize undesirable air currents which might cause unwanted disturbances on the surface of the lacquer coating.

enclosure means enclosing said applicator means and its associated drying stations and so disposed as to certain and separate said applicator means and said associated drying stations from the external environment, thereby preventing lacquer vapors from escaping from the area immediately surrounding said spray applicator means and said associated drying stations;

a motor mounted on each of said workpiece holding means and coupled to the panel support thereon for rotating said support and its associated panel;

preprogrammed control means situated as selected work stations for controlling said motors and the rotational speed thereof in order to spin said supports and panels at predetermined intervals and speeds; and

loading and unloading means for receiving panels to be conveyed to said first work station and for presenting for removal lacquered panels conveyed from a final work station.

10. The apparatus as defined in claim 9 wherein each of said panel supports carries a first sealing means, and wherein the spray applicator station and said associated drying stations each include a second sealing means, said first and second sealing means cooperating to at least partially seal a received panel within said spray applicator station and said associated drying stations, thereby containing lacquer vapors within the respective work stations.

11. Rotary apparatus for automatically processing and applying a lacquer coating over a phosphor coating on front panel areas of cathode ray tubes in a continuous step-by-step fashion while said panels are continuously maintained in a front-side-up attitude so that the phosphor coated surfaces of said panels are continuously directed downwardly, comprising:

an annular endless conveyor defining a predetermined processing path;

a plurality of workpiece holding means serially attached to said conveyor;

a rotatable panel support on each of said workpiece holding means for receiving and supporting a panel front side up such that the phosphor coated surface of said panel is directed downwardly during its processing;

a plurality of discrete work stations disposed around the perimeter of said conveyor for receiving said workpiece holding means and said front-side-up panels, each of said work stations being particularly adapted to perform at least one predetermined operation on said panels;

spray applicator means situated at at least one of said work stations for spraying a lacquer coating onto the downwardly directed phosphor coating on a received panel;

movable shroud means having an open end, and means for moving said shroud means vertically such that said shroud means at least partially surrounds said front-side-up panel only during the process of lacquer application to minimize undesirable air currents which might cause unwanted disturbances on the lacquer coating;

enclosure means enclsoing said spray applicator means and its associated drying stations and so disposed as to contain and separate said spray applicator means and said associated drying stations from the external environment, thereby preventing lacquer vapors from escaping from the area immediately surrounding said spray applicator means and associated drying stations;

preprogrammed control means situated at selected work stations for controlling the operation of said motor in order to spin said supports and said frontside-up support panels at predetermined intervals and speeds; and

12. The apparatus as defined in claim 11 wherein 13. Rotary apparatus for automatically processing and applying a lacquer coating over a phosphor coating on front panel areas of cathode ray tubes in a continuous step-by-step fashion while said panels are continuously maintained in a front-side-up attitude so that the phosphor coated surfaces of said panels are continuously directed downwardly, comprising:

an annular endless conveyor disposed along a predetermined processing path.

a plurality of workpiece holding means serially attached to said conveyor;

a rotatable panel support on each of said workpiece holding means for receiving and supporting a panel front side up such that the phosphor coating on said panel is directed downwardly;

a plurality of discrete work stations disposed around the perimeter of said conveyor for receiving said workpiece holding means and panels, each of said work stations being particularly adapted to perform at least one predetermined operation on said panels while said panel is supported in said frontside-up attitude;

developing means, situated at a first work station for receiving panels whose last phosphor coating is undeveloped and for developing said last phosphor coating by rinsing said panel with a solvent while in said front-side-up attitude to remove unexposed phosphor particles.

washing means situated at a second work station fol- I lowing said developing means for washing each panel as it arrives at said second work station;

spray applicator means situated at a third one of said work stations for spraying a lacquer coating on each received panel while in said front-side-up attitude;

movable shroud means having an open end and means for moving said shroud means vertically such that said shroud means at least partically surrounds said panel only during the process of lacquer application to minimize undesirable air currents which might cause unwanted distrubances on the surface of the lacquer coating;

enclosure means enclosing said spray applicator means and its associated drying stations and so disposed as to contain and separate said spray applicator means and said associated drying stations from the external environment, thereby preventing lacquer vapors from escaping from the area immediately surrounding said spray applicator means and associated drying stations;

preprogrammed control means situated at selected work stations for controlling said motors and the rotational speed thereof in order to cause said supports and panels to spin at predetermined intervals and speeds; and

14. The apparatus as defined in claim 13 wherein each of said panel supports carries a first sealing means, and wherein the spray applicator station and said associated drying stations each include a second sealing means, said first and second sealing means cooperating to at least partially seal a received panel within said spray applicator station and said associated drying stations, thereby containing lacquer vapors within the respective work stations.

Claims

1. Rotary apparatus for automatically applying a lacquer coating over a phosphor coating on partially processed front panels of cathode ray tubes in a continuous step-by-step fashion while said panels are continuously maintained in a front-side-up attitude so that the phosphor coated surfaces of said panels are continuously directed downwardly, comprising: an annular endless conveyor defining a predetermined processing path; a plurality of workpiece holding means serially attached to said conveyor for each receiving and supporting a panel front side up such that the phosphor coated surface of said panel is directed downwardly during its processing; a plurality of discrete work stations disposed around the perimeter of said conveyor for receiving said workpiece holding means and panels; indexing means for effecting step-by-step movement of said conveyor between said work stations; spray applicator means situated on at least one of said work stations for spraying a lacquer coating onto the downwardly directed phosphor coating of a received panel; moveable shroud means situated at the work station at which the lacquer coating is applied and means for positioning said shroud means over a panel to be coated in order to minimize undesirable air currents which might cause unwanted distrubances on the surface of the lacquer coating and to help contain lacquer vapors within the lacquer application work station; drying means situated at at least one of said work stations for drying said lacquer coating; and loading and unloading means for receiving panels to be conveyed to a first of said work stations and for presenting for removal lacquered panels conveyed from a final work station.

4. Rotary apparatus for automatically applying a lacquer coating over a phosphor coating on front panel areas of cathode ray tubes in a continuous step-by-step fashion, comprising: an annular endless conveyor disposed along a predetermined processing path; a plurality of workpiece holding means serially attached to said conveyor; a rotatable panel support on each of said workpiece holding means for receiving and supporting a panel during its processing; a plurality of discrete work stations disposed around the perimeter of said conveyor for receiving said workpiece holding means and panels; indexing means for effecting step-by-step movement of said conveyor between said work stations; spray applicator means situated at at least one of said work stations for spraying a lacquer coating into a received panel; movable shroud means having an open end and means for moving said shroud means vertically such that said shroud means at least partially surrounds said panel only during the process of lacquer application to minimize undesirable air currents which might cause unwanted disturbances on the surface of the lacquer coating; enclosure means enclosing said spray applicator means and associated drying stations and so disposed as to contain and separate said spray applicator means and said associated drying stations from the external enviroment, thereby preventing lacquer vapors from escaping from the area immediately surrounding said spray applicator means and associated drying station; a motor mounted on each of said workpiece holding means and coupled to the panel thereon for rotating said support and its associated panel; preprogrammed control means situated at selected work stations for controlling the operation of said motor in order to spin said supports and panels at predetermined intervals and speeds; and loading and unloading means for receiving panels to be conveyed to a fiRst of said work stations and for presenting for removal lacquered panels conveyed from a final work station.

8. The apparatus as defined in claim 4 wherein each of said panel supports carries a first sealing means, and the spray applicator station and said associated drying stations each include a second sealing means, said first and second sealing means cooperating to at least partially seal a received panel within said spray applicator station and said associated drying stations, thereby containing lacquer vapors within the respective work staions.

9. Rotary apparatus for automatically processing and applying a lacquer coating over a phosphor coating on front panel areas of cathode ray tubes in a continuous step-by-step manner, comprising: an annular endless conveyor defining a predetermined processing path; a plurality of workpiece holding means serially attached to said conveyor; a rotatable panel support on each of said workpiece holding means for receiving and supporting a panel during its processing; a plurality of discrete work stations disposed around the perimeter of said conveyor for receiving said workpiece holding means and panels, each of said work stations being particularly adapted to perform at least one predetermined operation on said panels; indexing means for effecting step-by-step movement of said conveyor between said work stations; developing means, situated at a first work station for receiving panels whose last phosphor coating is undeveloped and for developing said last phosphor coating by rinsing said panel with a solvent to remove unexposed phosphor particles; washing means situated at a second work station following said developing means for washing each panel as it arrives at said second work station; spray applicator means situtated at a third one of said work stations for spraying a lacquer coating on each received panel; movable shroud means having an open end, and means for moving said shroud means vertically such that said shroud means at least partially surrounds said panel only during the porcess of lacquer application to minimize undesirable air currents which might cause unwanted disturbances on the surface of the lacquer coating. enclosure means enclosing said applicator means and its associated drying stations and so disposed as to certain and separate said applicator means and said associated drying stations from the external environment, thereby preventing lacquer vapors from escaping from the area immediately surrounding said spray applicator means and said associated drying stations; a motor mounted on each of said workpiece holding means and coupled to the panel support thereon for rotating said support and its associated panel; preprogrammed control means situated as selected work stations for controlling said motors and the rotational speed thereof in order to spin said supports and panels at predetermined intervals and speeds; and loading and unloading means for receiving panels to be conveyed to said first work station and for presenting for removal lacquered panels conveyed from a final work station.

11. Rotary apparatus for automatically processing and applying a lacquer coating over a phosphor coating on front panel areas of cathode ray tubes in a continuous step-by-step fashion while said panels are continuously maintained in a front-side-up attitude so that the phosphor coated surfaces of said panels are continuously directed downwardly, comprising: an annular endless conveyor defining a predetermined processing path; a plurality of workpiece holding means serially attached to said conveyor; a rotatable panel support on each of said workpiece holding means for receiving and supporting a panel front side up such that the phosphor coated surface of said panel is directed downwardly during its processing; a plurality of discrete work stations disposed around the perimeter of said conveyor for receiving said workpiece holding means and said front-side-up panels, each of said work stations being particularly adapted to perform at least one predetermined operation on said panels; indexing means for effecting step-by-step movement of said conveyor between said work stations; spray applicator means situated at at least one of said work stations for spraying a lacquer coating onto the downwardly directed phosphor coating on a received panel; movable shroud means having an open end, and means for moving said shroud means vertically such that said shroud means at least partially surrounds said front-side-up panel only during the process of lacquer application to minimize undesirable air currents which might cause unwanted disturbances on the lacquer coating; enclosure means enclsoing said spray applicator means and its associated drying stations and so disposed as to contain and separate said spray applicator means and said associated drying stations from the external environment, thereby preventing lacquer vapors from escaping from the area immediately surrounding said spray applicator means and associated drying stations; a motor mounted on each of said workpiece holding means and coupled to the panel support thereon for rotating said support and its associated panel; preprogrammed control means situated at selected work stations for controlling the operation of said motor in order to spin said supports and said front-side-up support panels at predetermined intervals and speeds; and loading and unloading means for receiving panels to be conveyed to a first of said work stations and for presenting for removal lacquered panels conveyed from a final work station.

12. The apparatus as defined in claim 11 wherein each of said panel supports carries a first sealing means, and wherein the spray applicator station and said associated drying stations each include a second sealing means, said first and second sealing means cooperating to at least partially seal a received panel within said spray applicator station and said associated drying stations, thereby containing lacquer vapors within the respective work stations.

13. Rotary apparatus for automatically processing and applying a lacquer coating over a phosphor coating on front panel areas of cathode ray tubes in a continuous step-by-step fashion while said panels are continuously maintained in a front-side-up attitude so that the phosphor coated surfaces of said panels are continuously directed downwardly, comprising: an annular endless conveyor disposed along a predetermined processing path. a plurality of workpiece holding means serially attached to said conveyor; a rotatable panel support on each of said workpiece holding means for receiving and supporting a panel front side up such That the phosphor coating on said panel is directed downwardly; a plurality of discrete work stations disposed around the perimeter of said conveyor for receiving said workpiece holding means and panels, each of said work stations being particularly adapted to perform at least one predetermined operation on said panels while said panel is supported in said front-side-up attitude; indexing means for effecting step-by-step movement of said conveyor between said work stations; developing means, situated at a first work station for receiving panels whose last phosphor coating is undeveloped and for developing said last phosphor coating by rinsing said panel with a solvent while in said front-side-up attitude to remove unexposed phosphor particles. washing means situated at a second work station following said developing means for washing each panel as it arrives at said second work station; spray applicator means situated at a third one of said work stations for spraying a lacquer coating on each received panel while in said front-side-up attitude; movable shroud means having an open end and means for moving said shroud means vertically such that said shroud means at least partically surrounds said panel only during the process of lacquer application to minimize undesirable air currents which might cause unwanted distrubances on the surface of the lacquer coating; enclosure means enclosing said spray applicator means and its associated drying stations and so disposed as to contain and separate said spray applicator means and said associated drying stations from the external environment, thereby preventing lacquer vapors from escaping from the area immediately surrounding said spray applicator means and associated drying stations; a motor mounted on each of said workpiece holding means and coupled to the panel support thereon for rotating said support and its associated panel; preprogrammed control means situated at selected work stations for controlling said motors and the rotational speed thereof in order to cause said supports and panels to spin at predetermined intervals and speeds; and loading and unloading means for receiving panels to be conveyed to said first work station and for presenting for removal lacquered panels conveyed from a final work station.