Lens system for manufacturing crt screens
AssigneeKoninklijke Philips Electronics N.V.
InventorAlbertus Sluyterman
Life of this patent
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Abstract
A lens system (10, 20) is disclosed, comprising a first (13, 23) and a second (11, 21) lens. The refractive index of the second lens (11, 21) is higher than that of air, but lower than the refractive index of the first lens (13, 23). The lenses (13, 11, 23, 21) are arranged in direct contact with each other such that a critical refractive interface (22) is formed. The invention provides for exposure of CRT screens with a lower sensitivity to surface roughness, in particular when manufacturing screens with large deflection angles.
Claims7
A lens system for use in manufacturing CRT screens, the lens system comprising:
- a first lens having a first refractive index and
- a second lens having a second refractive index, the second refractive index being higher than the refractive index of air and lower than the first refractive index, wherein the first and the second lens each have an outer surface and a generally aspherical critical refractive surface, said critical refractive surfaces having complementary shapes and being arranged in direct contact with each other such that a refractive interface for the lens system is formed between the first and the second lens.
Dependencies are inferred from the claim text.