Thomson Consumer Electronics Inc.

Rca Thomson Licensing Corp.

Owen H Roberts, Jr

Peter M Ritt

Harry R Stork

Leonard P Wilbur, Jr

Charles M Wetzel

Istvan Gorog

Robert A Duschl

David Paul Ciampa

Peter David Southgate

Robert E Kreider

The invention includes an apparatus 40, 140 for developing a latent charge image formed on a photoreceptor 36 disposed on an interior surface of a faceplate panel 12. The apparatus 40, 140 comprises a developer tank 42 having a sidewall 44 closed at one end by a bottom portion 46 and at the other end by a panel support 48 having an opening 50 therethrough to provide access to the faceplate panel 12. The back electrode 52 has a potential applied thereto to establish an electrostatic drift field between the back electrode and the photoreceptor 36, which is grounded. Triboelectrically-charged, dry-powdered, light emitting phosphor material, having a charge of the same polarity as the potential applied to the back electrode 52, is injected into the developer tank 42, between the back electrode 52 and the faceplate panel 12. The triboelectrically-charged phosphor material is directed toward the photoreceptor 36 on the faceplate panel 12 by the applied electrostatic drift field. Panel skirt sidewall shields 66, 68 are disposed around a peripheral sidewall 18 of the faceplate panel 12 to repel the triboelectrically-charged phosphor material from the panel sidewall 18. The method of developing the latent charge image formed on the photoreceptor 36 that is disposed on an interior surface of a faceplate panel 12 includes the steps of placing the faceplate panel 12 on the panel support 48 of the apparatus 40, 140 and positioning the panel skirt sidewall shield means 66, 68 in proximity to the sidewall 18 of the of the faceplate panel 12. The photoreceptor 36 is grounded and a potential is applied to the back electrode 52. Triboelectrically-charged phosphor materials, having a charge of the same polarity as the potential applied to the back electrode 52 are introduced into the developer tank 42, between the back electrode 52 and the faceplate panel 12. The phosphor material is directed toward the photoreceptor 36 on the faceplate panel 12 by the applied electrostatic drift field and repelled from the sidewall 18 of the faceplate panel by the panel skirt sidewall shields 66, 68.

Apparatus and method of developing a latent charge image

In accordance with the present invention, a method for manufacturing a color CRT (10) having a faceplate panel (12) is disclosed. The method 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. 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), also is described. The PDM apparatus (90) 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.

Method and apparatus for manufacturing a color CRT

An apparatus (38) for rapidly and uniformly electrostatically charging a photoconductive layer (34) disposed on a conductive layer (32) provided on an interior concave surface of a viewing faceplate (18) of a CRT faceplate panel (12) is disclosed. The apparatus includes a housing (40) having a faceplate panel support surface (42), an electrical contact (52) for grounding the conductive layer, a corona charger (48), and power supplies (200, 204) for corona charging. The corona charger (48) includes a charging head (46) that substantially conforms to the contour of the interior concave surface of the viewing faceplate (18). The charging head comprises a base plate (54) having a mounting surface (56) to which a plurality of discrete charging modules (82) are attached. Each of the charging modules includes a focusing blade (86) and a charging blade (88, 188) insulated from the focusing blade. An ultimate focusing blade (186) is attached to the ultimate discrete charging module. The dimensions of the charging head are slightly less than the interior dimensions of the faceplate panel. The first power supply applies a first voltage to each of the charging blades and a second power supply applies a second voltage to each of the focusing blades. The apparatus further includes a motor (210) with an eccentric cam (212) that is connected by a shaft (214) to the charging head for laterally moving the charging head within the faceplate panel for a distance substantially equal to the periodic spacing (P) between charging blades of adjacent discrete charging modules, thereby providing a substantially uniform electrostatic charge to the photoconductive layer on the viewing faceplate.

Apparatus for charging an organic photoconductive layer for a CRT

In accordance with the present invention, a method of electrophotographically manufacturing a luminescent screen assembly on a photoreceptor disposed on an interior surface of a faceplate panel for a color CRT includes the steps of: charging the photoreceptor to establish a substantially uniform electrostatic voltage thereon; positioning the panel on an exposure device having a light source therein; exposing selected areas of the photoreceptor to visible light from the light source to affect the voltage thereon, without affecting the voltage on the unexposed area of the photoreceptor; and depositing a triboelectrically charged, first color-emitting phosphor onto the selected areas of the photoreceptor. The charging, positioning, exposing and depositing steps are repeated for a second and a third triboelectrically charged, color-emitting phosphor. The present method is an improvement over prior methods because after each of the phosphor deposition and panel recharging steps, the light source is offset in the exposure device by an amount determined by the voltage difference between the photoreceptor and the phosphor, or phosphors, previously deposited onto the panel, thereby counteracting the repulsive effect of the previously deposited phosphor and minimizing the misregister of subsequently deposited phosphors.

method of electrophotographic phosphor deposition

A solution for making a wear-resistant conductive contact patch for a faceplate panel of a color CRT which facilitates the electrophotographic manufacturing of a luminescent screen on the panel consists essentially of, in weight percent, solvent 22 to 70, conductive material 62 to 21, and the balance being other compatible additives.

Conductive contact patch for a CRT faceplate panel

The method of electrophotographically manufacturing a luminescent screen on a substrate of a color CRT, according to the present invention, includes the steps of forming a photoreceptor by sequentially coating the substrate to form a conductive layer and an overcoating of a photoconductive layer, establishing an electrostatic charge on the photoconductive layer, and exposing selected areas of the photoconductive layer to visible light to affect the charge thereon. Then the photoconductive layer is developed by the application of suitable triboelectrically charged, dry-powdered screen structure materials. The improved process provides at least one wear-resistant, conductive contact patch on a peripheral portion of a surface of the substrate. The contact patch has a first portion which underlies at least one of the layers of the photoreceptor and is in electrical contact with the conductive layer, and a second portion which extends from the photoreceptor. The contact patch is utilized during the manufacturing process to electrically ground the conductive layer during charging of the photoconductive layer. The contact patch also is utilized to measure the charge on the photoconductive layer during the developing process. Additionally, the contact patch provides an electrical contact, in the finished tube, between an aluminized layer on the screen and at least one support for a shadow mask.

Growing community of inventors

Landisville, PA, United States of America

Owen H Roberts, Jr