US4038524A — Data carrier optically readable by transmission a…

Claim 1

Independent Claim 127 words

A data carrier optically readable by transmission using an optical radiation, said data carrier comprising: a sheet of material transmitting said radiation; said sheet having at least one face carrying a permanent relief impression; said relief impression being in the form of a track; said track being made up of a succession of diffractive elements formed by alternating peaks and troughs constituting the transcription of a carrier wave angularly modulated by said data; said data carrier further comprising at least one protective layer transmitting said radiation; said protective layer having smooth faces and adhering by one of said smooth faces to said peaks without filling up said troughs; the bottom of said troughs being in contact with a space having a refractive index substantially equal to unity.

Claim 2

Dependent Claim 127 words

A data carrier optically readable by transmission using an optical radiation, said data carrier comprising: a sheet of material transmitting said radiation; said sheet having at least one face carrying a permanent relief impression; said relief impression being in the form of a track; said track being made up of a succession of diffractive elements formed by alternating peaks and troughs constituting the transcription of a carrier wave angularly modulated by said data; said data carrier further comprising at least one protective layer transmitting said radiation; said protective layer having smooth faces and adhering by one of said smooth faces to said peaks without filling up said troughs; the bottom of said troughs being in contact with a space having a refractive index substantially equal to unity.

Claim 3

Dependent Claim 40 words

A data carrier as claimed in claim 1, wherein said diffractive elements are constituted by depressions in the engraved face of said data carrier; said protective layer adhering to those portions of said engraved face at which no depressions occur.

Claim 4

Dependent Claim 34 words

A data carrier as claimed in claim 1, wherein said diffractive elements are constituted by elevations on the engraved face of said data carrier; said protective layer adhering to the tips of said elevations.

Claim 5

Dependent Claim 46 words

A data carrier as claimed in claim 1, wherein said protective layer adheres to the peaks of said relief, by welding; said welding being produced by dissolving a superficial section of said protective layer; said section having a thickness less than the depth of said relief.

Claim 6

Dependent Claim 38 words

A data carrier as claimed in any of claim 1, wherein the adhesion of said protective layer is achieved by means of an under-layer transmitting said radiation and having a thickness smaller than the depth of said relief.

Claim 7

Dependent Claim 22 words

A data carrier as claimed in claim 5, wherein said under-layer is a self-adhesive under-layer constituted by a film of plasticised material.

Claim 8

Dependent Claim 17 words

A data carrier as claimed in claim 5, wherein said under-layer is constituted by an adhesive material.

Claim 9

Dependent Claim 15 words

A data carrier as claimed in claim 1, wherein said data carrier is a disc.

Claim 10

Dependent Claim 20 words

A data carrier as claimed in claim 1, wherein said data carrier and said protective layer form a flexible structure.

Claim 11

Dependent Claim 36 words

A data carrier as claimed in claim 1, wherein the adhesion of said protective layer to said data carrier is supplemented by the formation of weld beads located outside the engraved areas of said data carrier.

Claim 12

Dependent Claim 43 words

A data carrier as claimed in claim 1, wherein said protective layer comprises an underlayer transmitting said radiation; said underlayer adhering to said relief impression along said peaks; said protective layer comprising a complementary layer transmitting said radiation and deposited on said underlayer.

Claim 13

Dependent Claim 39 words

A data carrier as claimed in claim 11, wherein said complementary layer has a thickness substantially greater than the depth of said relief impression; said complementary layer being overlayed with a thin film of hard material transmitting said radiation.

Claim 14

Dependent Claim 16 words

A data carrier as claimed in claim 12, wherein said underlayer is made of cellulose nitrate.

Claim 15

Independent Claim 113 words

A method of manufacturing a data carrier optically readable by transmission using an optical radiation, said method comprising the steps of: forming on at least one face of a sheet of material transmitting said radiation a permanent relief impression; said relief impression being in the form of a track made up of a succession of alternating peaks and troughs constituting the transcription of a carrier wave angularly modulated by said data; and causing a protective layer transmitting said optical radiation and having smooth faces to adhere to said peaks without filling up said troughs; the bottom of said troughs being in contact with a space having a refractive index substantially equal to unity.

Claim 16

Independent Claim 113 words

A method of manufacturing a data carrier optically readable by transmission using an optical radiation, said method comprising the steps of: forming on at least one face of a sheet of material transmitting said radiation a permanent relief impression; said relief impression being in the form of a track made up of a succession of alternating peaks and troughs constituting the transcription of a carrier wave angularly modulated by said data; and causing a protective layer transmitting said optical radiation and having smooth faces to adhere to said peaks without filling up said troughs; the bottom of said troughs being in contact with a space having a refractive index substantially equal to unity.

Claim 17

Dependent Claim 27 words

A method of manufacture as claimed in claim 14, wherein the adhesion of said protective layer is provided in accordance with the process of welding by dissolution.

Claim 18

Dependent Claim 40 words

A method as claimed in claim 14, wherein the adhesion of said protective layer is provided in accordance with a process comprising the step of spreading an adhesive material upon said protective layer in the form of a thin film.

Claim 19

Dependent Claim 22 words

A method of manufacture as claimed in claim 16, wherein said process is carried out with a device performing a liquid-phase coating.

Claim 20

Independent Claim 140 words

A method of manufacturing a data carrier optically readable by transmission using an optical radiation, said method comprising the steps of: forming on at least one face of a sheet of material transmitting said radiation a permanent relief impression; said relief impression being in the form of a track made up of a succession of alternating peaks and troughs constituting the transcription of a carrier wave angularly modulated by said data; dipping said sheet in a filtered solution containing a second material transmitting said radiation and a very volatile solvent of said second material, and withdrawing said sheet from said solution at a constant speed; subjecting said sheet to a drying in a dust-free atmosphere producing the rapid evaporation of said solvent so as to form a sub-layer on said relief impression; and, depositing a complementary layer on said sub-layer.

Claim 21

Independent Claim 140 words

A method of manufacturing a data carrier optically readable by transmission using an optical radiation, said method comprising the steps of: forming on at least one face of a sheet of material transmitting said radiation a permanent relief impression; said relief impression being in the form of a track made up of a succession of alternating peaks and troughs constituting the transcription of a carrier wave angularly modulated by said data; dipping said sheet in a filtered solution containing a second material transmitting said radiation and a very volatile solvent of said second material, and withdrawing said sheet from said solution at a constant speed; subjecting said sheet to a drying in a dust-free atmosphere producing the rapid evaporation of said solvent so as to form a sub-layer on said relief impression; and, depositing a complementary layer on said sub-layer.

Claim 22

Dependent Claim 19 words

A method as claimed in claim 18, wherein said second material is cellulose nitrate and said solvent is ether.

Claim 23

Dependent Claim 17 words

A method of manufacture as claimed in claim 16, wherein said process is a process of sticking.

Claim 24

Dependent Claim 17 words

A method of manufacture as claimed in claim 16, wherein said process is a process of self-adhesion.

Annuity Stage	Window Opens	Payment Deadline	Surcharge Period Until	Estimated Fee	Status
3.5 Years (Year 4)	1980-07-25	1981-01-24	1981-07-26	$2000.00	Window Closed / Lapsed
7.5 Years (Year 8)	1984-07-25	1985-01-24	1985-07-26	$3760.00	Window Closed / Lapsed
11.5 Years (Year 12)	1988-07-25	1989-01-24	1989-07-26	$7700.00	Window Closed / Lapsed

Data carrier optically readable by transmission and method of manufacturing such a data carrier

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