Patient interface device having an engineered surface for providing low friction and improved comfort to the user
A patient interface device includes an elastomeric contacting portion that is structured to directly engage the skin of the user. The contacting portion has an engineered surface that includes a plurality of non-random, predesigned surface features designed to reduce friction and improve user comfort. In one implementation, the pitch between each immediately adjacent pair of the surface features is less than or equal to a predetermined maximum pitch value, and the height of each of the surface features is less than or equal to a predetermined maximum height value.
1. A patient interface device, comprising:
a contacting portion structured to directly engage a user's skin during use of the patient interface device, wherein at least a section of the contacting portion has an engineered surface comprising a plurality of non-random, predesigned surface features each having a like geometry,
wherein in the section a pitch between each immediately adjacent pair of the surface features is:
(i) equal, or demonstrates anisotropic pitch such that the pitch between each immediately adjacent pair of the surface features in a first direction is equal to a first pitch value and the pitch between each immediately adjacent pair of the surface features in a second direction transverse to the first direction is equal to a second pitch value different than the first pitch value, and
(ii) less than or equal to a predetermined maximum pitch value, wherein the predetermined maximum pitch value is greater than or equal to 10 microns and less than or equal to 100 microns, and
wherein in the section a height of each of the surface features is less than or equal to a predetermined maximum height value.
2. The patient interface device according to claim 1 , wherein in the section the height of each of the surface features is equal to one another and less than or equal to the predetermined maximum height value.
3. The patient interface device according to claim 1 , wherein the predetermined maximum height value is greater than or equal to 10 microns and less than or equal to 20 microns.
4. The patient interface device according to claim 1 , wherein the predetermined maximum height value is any of: (i) 100 microns, (ii) 40 microns, (iii) 20 microns, or (iv) greater than or equal to 10 microns and less than or equal to 100 microns, or wherein the height of each of the surface features is any of: (i) greater than or equal to 10 microns and less than or equal to 40 microns, or (ii) greater than or equal to 10 microns and less than or equal to 20 microns.
5. The patient interface device according to claim 1 , wherein the at least a section of the contacting portion including the predesigned surface features is made of a material having a durometer of 2-55 Shore A.
6. The patient interface device according to claim 1 , wherein each of the surface features has an axi-symmetric dome-shaped profile.
7. The patient interface device according to claim 6 , wherein each of the surface features has a tip portion coupled to a base portion, wherein the tip portion has a radius of between 5 and 10 microns, and wherein the base portion has a half top angle measured with respect to a central axis of the surface feature equal to between 10 and 60 degrees.
8. The patient interface device according to claim 1 , wherein the engineered surface comprises a plurality of second surface features, each of the second surface features being a ridge member, each of the surface features being a pillar member formed by an intersection of four adjacent ones of the ridges.
9. The patient interface device according to claim 1 , wherein the contacting portion is part of a seal of the patient interface device.
10. The patient interface device according to claim 1 , wherein each of the surface features comprises one of the following types of surface features: a bump, a dimple, a pillar, a dome, a valley, a ridge, an undulation or a serration.
11. A method of making a patient interface device, comprising:
designing an engineered surface wherein at least a section of the engineered surface comprises a plurality of non-random, predesigned surface features each having a like geometry, wherein in the section a pitch between each immediately adjacent pair of the surface features is (i) equal, or demonstrates anisotropic pitch such that the pitch between each immediately adjacent pair of the surface features in a first direction is equal to a first pitch value and the pitch between each immediately adjacent pair of the surface features in a second direction transverse to the first direction is equal to a second pitch value different than the first pitch value, and (ii) less than or equal to a predetermined maximum pitch value, wherein the predetermined maximum pitch value is any of: (i) 50 microns, (ii) 100 microns, or (iii) greater than or equal to 10 microns and less than or equal to 10 microns and less than or equal to 100 microns, or wherein the pitch between each immediately adjacent pair of the surface features is any of: (i) greater than or equal to 10 microns and less than or equal to 50 microns, or (ii) greater than or equal to 20 microns and less than or equal to 50 microns, and wherein in the section a height of each of the surface features is less than or equal to a predetermined maximum height value; and
forming a contacting portion for the patient interface device in a manner wherein the contacting portion includes the engineered surface, the contacting portion being structured to directly engage a user's skin.
12. The method according to claim 11 , wherein the predetermined maximum height value is any of: (i) 100 microns, (ii) 40 microns, (iii) 20 microns, or (iv) greater than or equal to 10 microns and less than or equal to 100 microns, or wherein the height of each of the surface features is any of: (i) greater than or equal to 10 microns and less than or equal to 40 microns, or (ii) greater than or equal to 10 microns and less than or equal to 20 microns.
13. The patient interface device according to claim 6 , wherein in the section the pitch between each immediately adjacent pair of the surface features is 10-30 microns, wherein each of the surface features has a base portion having a radius of 5-7.5 microns, wherein in the section the height of each of the surface features is less than or equal to 10 microns, and wherein a deflection of each of the surface features is equal to 1 micron or less in response to a normal pressure of 0.01 MPa.
14. The patient interface device according to claim 13 , wherein the contacting portion is made of a material having a durometer of 5 Shore A and an elastic modulus of 0.1-1.5 MPa.
15. The method according to claim 11 , wherein the contacting portion is made of a material having a durometer of 2-55 Shore A.
16. The patient interface device according to claim 1 , wherein a deflection of each of the surface features is equal to 1 micron or less in response to a normal pressure of 4.4 kPa.
17. The method according to claim 11 , wherein in the section the height of each of the surface features is equal to one another and less than or equal to the predetermined maximum height value.
18. The patient interface device according to claim 1 , wherein the pitch between each immediately adjacent pair of the surface features is greater than or equal to 20 microns and less than or equal to 50 microns.
19. The method according to claim 11 , wherein the predetermined maximum height value is greater than or equal to 10 microns and less than or equal to 20 microns.
20. The method according to claim 11 , wherein the pitch between each immediately adjacent pair of the surface features is greater than or equal to 20 microns and less than or equal to 50 microns.