# US 11,298,968 B2 · Method for labeling products with a transparent photoluminescent label, and transparent photoluminescent label

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- Number: US 11,298,968 B2
- Document ID: US11298968B2
- Status: Granted
- Kind: B2
- Application number: 16/988,238
- Filed: 2020-08-07
- Published: 2020-11-26
- Granted: 2022-04-12
- Earliest claimed: 2020-08-07
- Assignees: Ecole Polytechnique Federale de Lausanne
- Applicants: Ecole Polytechnique Federale De Lausanne (Epfl)
- Inventors: Nasser Hefyene; Nicolas Grandjean
- Web page: https://patentgrep.com/patent/US11298968B2

## CPC

- B42D 25/387: absorbing or reflecting ultraviolet light
- B42D 25/36: comprising special materials
- B42D 25/373: Metallic materials
- B42D 25/415: using chemicals (B42D25/445 takes precedence)
- B42D 25/43: by removal of material
- B42D 25/465: using chemicals or adhesives
- C09K 11/0883: {Arsenides; Nitrides; Phosphides}
- C09K 11/62: containing gallium, indium or thallium
- C09K 11/64: containing aluminium
- C23C 14/042: {using masks}
- C23C 14/0617: {AIII BV compounds, where A is Al, Ga, In or Tl and B is N, P, As, Sb or Bi}
- C23C 16/042: {using masks}
- C23C 16/303: {Nitrides}
- G04B 39/00: Watch crystals; Fastening or sealing of crystals; Clock glasses
- G04B 39/006: {out of wear resistant material, e.g. sapphire}
- G04B 45/0015: {Light-, colour-, line- or spot-effects caused by or on stationary parts (change of appearance by exchangeable case parts G04B47/046)}
- G04B 45/0084: {Pictures or inscriptions on the case or parts thereof, attaching complete pictures (decoration and manfuacture thereof G04B45/0076; special decorative parts which are attached to the case or other parts G04B47/04)}
- G09F 3/0294: {where the change is not permanent, e.g. labels only readable under a special light, temperature indicating labels and the like}
- G09F 2003/0213: {Concealed data}
- B42D: BOOKS; BOOK COVERS; LOOSE LEAVES; PRINTED MATTER CHARACTERISED BY IDENTIFICATION OR SECURITY FEATURES; PRINTED MATTER OF SPECIAL FORMAT OR STYLE NOT OTHERWISE PROVIDED FOR; DEVICES FOR USE THEREWITH AND NOT OTHERWISE PROVIDED FOR; MOVABLE-STRIP WRITING OR READING APPARATUS
- C09K: MATERIALS FOR MISCELLANEOUS APPLICATIONS, NOT PROVIDED FOR ELSEWHERE
- C23C: COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; SURFACE TREATMENT OF METALLIC MATERIAL BY DIFFUSION INTO THE SURFACE, BY CHEMICAL CONVERSION OR SUBSTITUTION; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL (making metal-coated products by extrusion B21C23/22; covering with metal by connecting pre-existing layers to articles, see the relevant places, e.g. B21D39/00, B23K; metallising of glass C03C; metallising mortars, concrete, artificial stone, ceramics or natural stone C04B41/00; enamelling of, or applying a vitreous layer to, metals C23D; treating metal surfaces or coating of metals by electrolysis or electrophoresis C25D; single-crystal film growth C30B; by metallising textiles D06M11/83; decorating textiles by locally metallising D06Q1/04)
- G04B: MECHANICALLY-DRIVEN CLOCKS OR WATCHES; MECHANICAL PARTS OF CLOCKS OR WATCHES IN GENERAL; TIME PIECES USING THE POSITION OF THE SUN, MOON OR STARS (spring- or weight-driven mechanisms in general F03G; electromechanical clocks or watches G04C; electromechanical clocks with attached or built-in means operating any device at pre-selected times or after predetermined time intervals G04C23/00; clocks or watches with stop devices G04F7/08)
- G09F: DISPLAYING; ADVERTISING; SIGNS; LABELS OR NAME-PLATES; SEALS

## Abstract

A method for marking a product (1) with a photoluminescent mark, said mark comprising a photoluminescent portion (10) which is transparent under normal light conditions and revealed by photoluminescence under UV illumination, said mark further comprising a non photoluminescent portion (9) which is transparent under normal light conditions as well s under UV illumination, said method comprising: deposing on said product a stack, said stack comprising alternatively layers (2,4) such as AlN, with a thickness of less than 1 micron and layers (3) of a second material, such as GaN with a thickness of less than 10 nm; raising the transparency of said non photoluminescent portion (10) with a deposition of transparent material (6) or incorporation of ions into said non photoluminescent portions.

## Claims

### Claim 1

A product comprising a photoluminescent pattern, wherein said pattern comprises:
a photoluminescent portion which is transparent under normal light conditions and revealed by photoluminescence under UV illumination, said photoluminescent portion comprising a stack comprising successive pairs of layers, said pairs of layers each comprising a first layer of a first material with a thickness of less than or equal to 1 micron and a second layer of a second material with a thickness of less than or equal 10 nm, wherein the interface between the first layer and the second layer of the pairs of layers includes quantum nano-structures;
a non-photoluminescent portion which is transparent under normal light conditions as well as under UV illumination, said non-photoluminescent portion comprising an additional transparent material or ions for raising the transparency.

### Claim 2 (depends on 1)

The product of claim 1, wherein said ions include Oxygen, Nitrogen, Hydrogen, Helium, Neon, Argon, Magnesium, Lithium, Beryllium, Boron, Phosphor, Aluminum, Zinc, Arsenic, Gallium, Silicon, Cadmium and/or any element capable of degrading the photoluminescent stack and creating non-radiative recombination center defects into the stack.

### Claim 3 (depends on 1)

The product of claim 1, wherein said transparent material as a refractive index substantially equal to the refractive index of said stack.

### Claim 4 (depends on 1)

The product of claim 1, wherein said product is transparent.

### Claim 5 (depends on 1)

The product of claim 1, wherein said stack comprises fewer than or equal to 100 layers.

### Claim 6 (depends on 1)

The product of claim 1, wherein said second layers of second material comprise GaN alloys with less than 50% of Indium, Aluminum, Arsenic and/or Phosphor.

### Claim 7 (depends on 1)

The product of claim 1, wherein said second layers of second material comprise less than or equal to 10% rare-earth elements.

### Claim 8 (depends on 1)

The product of claim 1, wherein said quantum nano-structures comprise quantum dots.

### Claim 9 (depends on 1)

The product of claim 1, wherein said first layers of first material comprise less than 20% of Magnesium, Silicon, Lithium, Beryllium, Cadmium and/or Zinc as dopant elements.

### Claim 10 (depends on 1)

The product of claim 1, wherein said ions include Oxygen, Nitrogen, Hydrogen, Helium, Neon, Argon, Magnesium, Lithium, Beryllium, Boron, Phosphor, Aluminum, Zinc, Arsenic, Gallium, Silicon, or Cadmium.

### Claim 11 (depends on 1)

The product of claim 1, wherein said ions are disposed in a pattern.

### Claim 12 (depends on 11)

The product of claim 11, wherein said pattern comprises alpha-numeric text, figures, drawings, identification codes, or logos.

### Claim 13 (depends on 1)

The product of claim 1, wherein said transparent material has a refractive index substantially equal to the refractive index of said stack.

### Claim 14 (depends on 1)

The product of claim 1, Wherein the photoluminescent portion emits light in response to UV illumination and the color of light emitted by the photoluminescent portions depends on the intensity of the UV illumination.

### Claim 15 (depends on 1)

The product of claim 1, wherein said UV illumination comprises UV wavelengths of less than or equal 400 nm.

### Claim 16 (depends on 1)

The product of claim 1, wherein the transparent material covers the photoluminescent portion.

### Claim 17 (depends on 1)

The product of claim 1, wherein the non-photoluminescent portion comprises the stack and wherein the stack of the non-photoluminescent portion comprises non-radiative defects that deactivate the photoluminescent ability of the stack in the non-photoluminescent portion.

### Claim 18 (depends on 1)

The product of claim 1, wherein the photoluminescent portion emits light in response to UV illumination and the color of light emitted by the photoluminescent portions depends on the quantum nano-structure size.

### Claim 19 (depends on 1)

The product of claim 1, wherein at least one layer of second material is roughened.

### Claim 20 (depends on 1)

The product of claim 1, wherein the quantum nano-structures are quantum wires, quantum wells, or quantum dots.