Antireflection optical coating with antistatic properties

Claim 2

In an optical article, a transparent substrate having two major surfaces, and an optical coating formed on one of said two major surfaces on the side of incident radiation and having an antireflection optical coating comprising a first thin film layer of transparent dielectric material having low index of refraction, a second thin film layer of transparent dielectric material having high index of refraction, and a third layer of transparent material having substantial electrical conductivity and high index of refraction, said third layer being positioned beneath the top surface of said optical coating with at least one surface thereof adjacent said layer of high refractive index material.

Claim 3

The optical article of Claim 1, wherein said third layer of transparent material lies between said first and second layers.

Claim 4

The optical article of Claim 1, further comprising a fourth thin film layer of transparent dielectric material having high index of refraction, said third layer of transparent material being formed between said second and fourth layers.

Claim 5

The optical article of Claim 2, wherein the optical thickness of said third layer is less than about twenty-five percent of the total optical thickness of said second and third layers.

Claim 6

The optical article of Claim 3, wherein the optical thickness of said third layer is less than about twenty-five percent of the total optical thickness of said second, third and fourth layers.

Claim 7

In an optical article, a transparent substrate having two major surfaces, and an optical coating formed on one of said two major surfaces on the side of incident radiation and having an antireflection optical response to said incident radiation, said optical coating comprising a first thin film layer on the side of incident radiation and formed of a transparent dielectric material having low index of refraction, and a composite thin film layer adjacent said first thin film layer and formed from a plurality of layers of transparent material having high index of refraction including at least one layer of a dielectric material and at least one layer of transparent material having substantial electrical conductivity.

Claim 8

In an optical article, a transparent substrate having two major surfaces, and an optical coating formed on one of said two major surfaces on the side of incident radiation and having an antireflection optical response to said incident radiation, said optical coating comprising a first thin film layer on the side of incident radiation and formed of a transparent dielectric material having low index of refraction, and a composite thin film layer adjacent said first thin film layer and formed from a plurality of layers of transparent material having high index of refraction including at least one layer of a dielectric material and at least one layer of transparent material having substantial electrical conductivity.

Claim 9

The optical article of Claim 6, wherein the optical thickness of said layer of material having substantial electrical conductivity is less than twenty-five percent of the total optical thickness of said composite thin film layer.

Claim 10

The optical article of Claim 6 or Claim 7, wherein said layer of material having substantial electrical conductivity is formed in contact with said first thin film layer.

Claim 11

The optical article of any of Claims 6 to 8, wherein said composite thin film layer comprises two layers of said dielectric material and said layer of material having substantial electrical conductivity is formed between said two separate layers.

Claim 12

A cathode ray tube having a face panel arrangement with an electron sensitive light emitting phosphor on an interior surface thereof and an antireflection optical coating formed on a front exterior surface thereof, said optical coating comprising a first thin film layer on the side of said incident radiation and formed of a transparent dielectric material having low index of refraction, and a composite thin film layer adjacent said first thin film layer and formed from a plurality of layers including at least one layer of a dielectric material and at least one layer of transparent material having substantial electrical conductivity, said layer of material having substantial electrical conductivity being adapted to be connected to an electrical ground to prevent static charge build up on said face panel.

Claim 13

A cathode ray tube having a face panel arrangement with an electron sensitive light emitting phosphor on an interior surface thereof and an antireflection optical coating formed on a front exterior surface thereof, said optical coating comprising a first thin film layer on the side of said incident radiation and formed of a transparent dielectric material having low index of refraction, and a composite thin film layer adjacent said first thin film layer and formed from a plurality of layers including at least one layer of a dielectric material and at least one layer of transparent material having substantial electrical conductivity, said layer of material having substantial electrical conductivity being adapted to be connected to an electrical ground to prevent static charge build up on said face panel.

Claim 14

The cathode ray tube of Claim 10, wherein the optical thickness of said layer of material having substantial electrical conductivity is less than twenty-five percent of the total optical thickness of said composite thin film layer.

Claim 15

The cathode ray tube of Claim 10 or Claim 11, wherein said antireflection coating is formed directly on the face panel of said cathode ray tube.

Claim 16

The cathode ray tube of any of Claim 10 to 12 wherein said face panel arrangement comprises the face panel of said tube and a separate transparent panel bonded to the front surface of said face panel, said antireflection optical coating being formed on a front surface of said separate transparent panel.