Correcting lenses utilized in the manufacture of fluorescent screen of color picture tubes

• US 4,052,123 A
• Filed: 09/29/1975
• Issued: 10/04/1977
• Est. Priority Date: 11/29/1971
• Status: Expired due to Term

• Current Assignee: Hitachi, Ltd.
• Original Assignee: Hitachi, Ltd.
• Inventors: Yamazaki, Eiichi, Maruyama, Koichi, Ueda, Toshio
• Primary Examiner(s): Corbin, John K.
• Assistant Examiner(s): Clark, Conrad
• Application Number:
  US05/617,939
• Time in Patent Office: 736 Days
• Field of Search: 350/189, 350/193, 350/194, 350/211, 350/213, 354/1
• US Class Current: 359/742
• CPC Class Codes: G02B 3/08 with discontinuous faces, e.g. Fresnel lens diffractive Fresnel lenses G02B5/1876
• CPC Class Codes: H01J 9/2273 Auxiliary lenses and filters

Abstract

The correcting lens comprises a plurality of regions which are formed at at least one portions of the effective surfaces on both sides of the lens by means of a plurality of border lines which are discontinuous in only one direction. The regions on one side are inclined in a direction different from that of the regions on the opposite side of the lens.

Claims

1. A correcting lens of an exposure device utilized to form a fluorescent screen of a colour picture tube, the correcting lens having effective surfaces on opposite sides thereof, each effective surface comprising a plurality of regions divided by a plurality of border lines and each having a specified refractive characteristic to exposure light, said border lines on the respective sides dividing one effective surface of the correcting lens in a direction different from another direction in which the opposite effective surface of the correcting lens is divided, and being discontinuous in only one direction, the regions on said opposite sides being inclined in substantially different directions to provide said specified refractive characteristic such that the exposure light path through the correcting lens approximates the ultimate electron beam locus by cooperation of the regions on one side of the correcting lens with those on the opposite side thereof, and wherein said correcting lens comprises a plurality of regions, at least one portion of the effective surface on one side of said correcting lens having a plurality of concentric border lines which are discontinuous in the radial direction for dividing said regions.

2. The correcting lens according to claim 1 wherein the surfaces of the regions on both sides are flat.

3. The correcting lens according to claim 1 wherein the surfaces of the regions on both sides of the correcting lens are curved.

4. The correcting lens according to claim 1 wherein said border lines which are discontinuous in only one direction are parallel with each other.

5. The correcting lens according to claim 1 wherein the regions divided by said discontinuous border lines are inclined substantially in the same direction.

6. A correcting lens for use in the formation of a colour picture tube screen including,

a first effective surface comprising a plurality of parallel stripe-shaped elements separated by boundaries of discontinuity, each of said elements separately contoured to reduce a misregister in said tube, and

a second effective surface opposite said first effective surface, said second effective surface comprising a plurality of elements separated by boundaries of discontinuity, each of said elements of said second effective surface separately contoured to additionally reduce misregister in said tube wherein said second effective surface comprises concentric annular ring-shaped elements.

7. A correcting lens for use in the formation of a colour picture tube screen comprising,

two effective surfaces on opposite sides of said lens, each surface comprising a plurality of elements separated by boundaries of discontinuity, one of said surfaces having concentric circular boundaries of discontinuity and elements on opposite sides of said lens contoured to cooperatively reduce misregister in said tube.