Methods for managing the scattering of incident light and articles created therefrom
The present disclosure provides engineered surfaces that exhibit reduced specular reflection and gloss while still providing a high intensity of reflected light at multiple incident angles. The structured metal surfaces include engineered topography that increases diffuse reflection, leading to a greater intensity of light perceived at multiple viewing angles. A viewer engaging such surfaces is likely to perceive a stronger ‘white’ reflection of the incident light and an improvement, particularly in orthodontic and other oral applications, of aesthetic appearance. Methods of creating the engineered surfaces and orthodontic articles incorporating the engineered surfaces are also disclosed.
1. An orthodontic archwire comprising:
an exterior surface including metal; and
a plurality of engineered features on the exterior surface, wherein the engineered features include a plurality of recesses in the exterior surface, wherein the average depth of the plurality of recesses is at least 0.5 microns and no greater than 20 microns, wherein the pitch between adjacent recesses is at least 15 microns and no greater than 60 microns, and wherein the surface including the plurality of features provides an engineered surface that exhibits a Total CIE Chroma of no greater than 14 and a minimum L* value of at least 20 at an incident angle of 0 degrees and a view angle of 70 degrees, as measured by the Diffuse Scattering Test.
2. The orthodontic archwire of claim 1 , wherein the recesses are arranged in an array having a transverse axis and a longitudinal axis, and wherein the pitch between adjacent recesses along the transverse axis is greater than a pitch between adjacent recesses along the longitudinal axis.
3. The orthodontic archwire of claim 2 , wherein the cross-sectional dimension includes a diameter, the diameter is at least 25 and no greater than 35 microns, and wherein the pitch is at least 25 and no greater than 35 microns.
4. The orthodontic archwire of claim 1 , wherein the plurality of recesses are arranged in a periodic array, and wherein the surface includes interstitial space between any two recesses in an array, and, wherein the interstitial space between recesses include one or more protrusive features.
5. The orthodontic archwire of claim 1 wherein at least one recess includes protrusive features on a bottom surface of the recess.
6. The orthodontic archwire of claim 1 , wherein the surface exhibits a L* ratio of at least 0.4 in the absence of any aesthetic coating.
7. The archwire of claim 1 wherein at least one recess includes a depth of about 10 microns.
8. The orthodontic archwire of claim 1 , the exterior surface is an electroplated metal coating.
9. The orthodontic archwire of claim 1 , wherein an electroplated metal coating is disposed on the engineered surface.
10. The orthodontic archwire of claim 1 , wherein at least 75% of the area of the engineered surface is contained within the recesses.
11. The orthodontic archwire of claim 8 , wherein the electroplated metal coating comprises at least one of aluminum and rhodium.
12. The orthodontic archwire of claim 9 , wherein at least one recess of the plurality of recesses is arranged in a unit cell with at least two other recesses, and wherein the pitch between recesses in the unit cell is at least 20 microns and no greater than 50 microns.
13. The orthodontic archwire of claim 9 , wherein the electroplated metal coating comprises at least one of aluminum and rhodium.