Transparent optical element for a motor vehicle

Abstract

A transparent optical element for a motor vehicle includes at least one first transparent layer of a polymer material. The optical element further has at least one second transparent layer including at least silicon, titanium, oxygen and nitrogen.

Claims

1. A transparent optical element, for a motor vehicle comprising at least one first transparent layer of a polymer material, wherein the optical element further comprises at least one second transparent layer comprising at least silicon, titanium, oxygen and nitrogen. the second layer comprises a nitrogen derivative of titanium dioxide of formula: TiO.sub.2-xN.sub.x with 0.001<x<1.00, and the second layer has a core/shell structure wherein at least one particle of SiO.sub.2 is covered by a shell of nanoparticles of TiO.sub.2-xN.sub.x distributed on a surface of said particle of SiO.sub.2.

2. The optical element according to claim 1, wherein the second layer comprises: one or more silicon-oxygen (Si—O) groups, one or more titanium-oxygen (Ti—O) groups, and one or more titanium-nitrogen (Ti—N) groups.

3. The optical element according to claim 1, wherein 0.01≤×≤0.10.

4. The optical element according to claim 1. wherein the second layer has a. thickness of at most 100 nm.

5. The optical element according claim 1, wherein the second layer is a hydrophilic layer.

6. The optical element according to claim 1, characterized in that wherein the second layer is directly in physical contact with the first layer.

7. The optical element according to claim 1, wherein the polymer material of the first layer comprises at least one polymer P chosen from among polycarbonate (PC), high temperature modified polycarbonate (PC-HT), polymethyl methacrylate (PMMA), polymethacrylimide (PMMI), cyclo-olefin polymer (COP), cyclo-olefin copolymer (COC), polysulfone (PSU), polyarylate (PAR), transparent polyarmide (PA), and mixtures thereof.

8. The optical element according to claim 1, wherein the element is a closure outer lens of a lighting device.

9. The optical element according to claim 8, wherein the closure outer lens of a lighting device comprises an interior face and an exterior face, the first layer being the exterior face of the closure outer lens.

10. The optical element according to claim 1, wherein a ratio of a mean diameter of the nanoparticles of TiO.sub.2-xN.sub.x to a mean diameter of the particles of SiO.sub.2 is abo 1:10.

11. The optical element according to claim 1, wherein the first transparent layer has a thickness of 1.0 mm to 5 mm.

12. A lighting device of a motor vehicle, comprising the transparent optical element according to claim 1.

Description

EXAMPLE

(1) Fabrication of an Optical Element According to the Invention

(2) The support used as the first layer is a transparent polycarbonate (PC), marketed by the company KUDEB under the brand M.AL2447. This polycarbonate is in the form of a rectangular sheet with the following dimensions: 15 cm in length, 10.5 cm in width, and 3.2 mm in thickness.

(3) The following compounds were used: PR1: TEOS marketed by the company Sigma Aldrich under the brand 86578 purity ≥99% (CAS No. 78-10-4); PR 2: TTIP marketed by the company Sigma Aldrich under the brand 87560 purity≥97% (CAS No. 546-68-9); and The nitrogen used as the carrier and dopant gas is marketed by the company Air Liquide under the brand Alphagaz 1 Azote (CAS No. 7727-37-9).

(4) The atmospheric plasma method is carried out.

(5) The power of the generator powering the electrode is 1000 Watts. The mass flow rate of precursor PR1 TEOS is 1.5 ml.sub.s/min and the flow rate of precursor PR2 TTIP is 0.1 ml.sub.s/min, the flow rate of the dopant gas (N.sub.2) is 50 ml.sub.s/min, the flow rate of air (O.sub.2) is 100 mLm. The distance between the nozzle and the substrate is 15 mm. The rate of deposition is set at 100 mm per second.

(6) One thus obtains a first layer of PC comprising a second layer of silicon, titanium, oxygen and nitrogen, deposited directly on its surface, the second layer having a thickness of around 85 nm.

(7) This second layer is characterized by a structure of “core/shell” type, in which at least one particle of SiO.sub.2 is covered by a shell of nanoparticles of TiO.sub.2-xN.sub.x distributed on the surface of said particle of SiO.sub.2. The ratio of the mean diameter of the nanoparticles of TiO.sub.2-xN.sub.x to the mean diameter of the particles of SiO.sub.2 is around 1:10. This structure was characterized by using SEM/EDS (scanning electron microscope outfitted with a probe).

(8) Various tests were conducted on the piece so treated:

(9) 1—Evaluation of the Anti-Condensation Effect:

(10) The samples were placed above a kettle containing water for one minute and then laid flat and left for 10 minutes at 60° C. The samples were then left for 3 days at room temperature (23° C.) in an unconfined atmosphere. The test of exposure to the kettle is repeated (20 times). Observation shows there is no visible condensation in the zone treated according to the invention whereas it is very visible, with formation of droplets of condensed water, on a specimen not treated according to the invention.

(11) 2—Climate Cycles

(12) The samples were placed: for 16 hours at 85° C. in an atmosphere with relative humidity of 95%, then for 3 hours at −20° C. in a dry atmosphere (relative humidity equal to 0%), and finally for 6 hours at 85° C. in an atmosphere with relative humidity less than 30%.
The cycle is repeated 5 times. No alteration or modification of the appearance of the treatment was observed.
3—Angle of Contact

(13) The angle of contact with distilled water is less than 10°, showing the elevated level of hydrophilia of the second layer realized according to the invention (“superhydrophilia”). This characteristic is preserved after tests 1 and 2.