Lens, electromagnetic lens assembly having the lens, and wireless communication device having the electromagnetic lens assembly
A wireless communication device includes a casing having a wireless signal penetrating area, an antenna sending a wireless signal through the wireless signal penetrating area, and an electromagnetic lens assembly including a lens barrel and a lens. The lens barrel has a first end and a second end. The first end is closer to the wireless signal penetrating area than the second end. The lens disposed in the lens barrel has an incident surface and an emission surface on an axis of the lens. The incident surface is a flat surface facing the first end. The emission surface is a convex surface and has a curvature, which is not equal to 0, from a perspective of a first axis perpendicular to the axis of the lens, and has a curvature of 0 from a perspective of a second axis perpendicular to the axis of the lens and the first axis.
1. A wireless communication device, comprising:
a casing and an antenna, wherein the casing has a wireless signal penetrating area; the antenna located in the casing corresponds to the wireless signal penetrating area and sends a wireless signal through the wireless signal penetrating area; and
an electromagnetic lens assembly comprising a lens barrel and a lens, wherein the lens barrel has a first end and a second end opposite to the first end on an axis of the lens barrel; the first end is closer to the wireless signal penetrating area than the second end; the lens is disposed in the lens barrel for concentrating an electromagnetic wave; the lens has an incident surface and an emission surface on an axis of the lens, wherein the incident surface of the lens is a flat surface and faces the first end, and the emission surface is a convex surface; the emission surface has a curvature, which is not equal to 0, from a perspective of a first axis perpendicular to the axis of the lens, and has a curvature of 0 from a perspective of a second axis perpendicular to the axis of the lens and the first axis;
wherein a radius of a projection circle that the emission surface projects along the axis of the lens is defined as R; a curvature radius of the emission surface on the second axis is defined as Rc; a distance between the incident surface and the antenna on the axis of the lens is defined as D; the lens satisfies 0.50≤R/Rc≤0.6 and 0.4≤R/D≤0.5.
2. The wireless communication device as claimed in claim 1 , wherein an inner wall of the lens barrel has a shoulder portion; the lens is a cylinder and has a flange portion protruding in a radial direction of the lens; the flange portion abuts against the shoulder portion.
3. The wireless communication device as claimed in claim 2 , wherein the lens barrel comprises a tube body and a protective cover; the tube body has the first end and the shoulder portion; the shoulder portion abuts against a side of the flange portion on the axis of the lens; the protective cover is engaged with the tube body and has an abutting portion abutting against another side of the flange portion on the axis of the lens.
4. The wireless communication device as claimed in claim 3 , wherein the flange portion has at least one notch, and an inner wall of the tube body of the lens barrel has at least one first positioning rib entering the at least one notch to restrict the lens from rotating.
5. The wireless communication device as claimed in claim 4 , wherein the at least one first positioning rib includes two first positioning ribs respectively abut against two sides of the at least one notch; the protective cover has two second positioning ribs entering between the two first positioning ribs and respectively abutting against the two first positioning ribs.
6. The wireless communication device as claimed in claim 3 , wherein an inner wall of the tube body has a plurality of supporting ribs constituting the shoulder portion; the protective cover has a plurality of abutting ribs constituting the abutting portion.
7. The wireless communication device as claimed in claim 1 , wherein the second end of the lens barrel is an open end; the lens is located between the first end and the second end, and the emission surface faces the second end; an anti-ultraviolet coating is at least provided on the emission surface of the lens.
8. The wireless communication device as claimed in claim 1 , wherein the casing comprises a body and a flat lens; the body has an opening; the flat lens is disposed on the body and is located at the opening and constitutes the wireless signal penetrating area.
9. An electromagnetic lens assembly, comprising:
a lens barrel having a first end and a second end opposite to the first end on an axial direction of the lens barrel; and
a lens disposed in the lens barrel for concentrating an electromagnetic wave, wherein the lens has an incident surface and an emission surface on an axis of the lens; the incident surface is a flat surface facing the first end; the emission surface is a convex surface, and has a curvature, which is not equal to 0, from a perspective of a first axis perpendicular to the axis of the lens, and has a curvature of 0 from a perspective of a second axis perpendicular to the axis of the lens and the first axis;
wherein a radius of a projection circle that the emission surface projects along the axis of the lens is defined as R; a curvature radius of the emission surface on the second axis is defined as Rc; the lens satisfies 0.50≤R/Rc≤0.6.
10. The electromagnetic lens assembly as claimed in claim 9 , wherein an inner wall of the lens barrel has a shoulder portion; the lens is a cylinder and has a flange portion protruding in a radial direction of the lens; the flange portion abuts against the shoulder portion.
11. The electromagnetic lens assembly as claimed in claim 10 , wherein the lens barrel comprises a tube body and a protective cover; the tube body has the first end and the shoulder portion; the shoulder portion abuts against a side of the flange portion on the axis of the lens; the protective cover is engaged with the tube body and has an abutting portion abutting against another side of the flange portion on the axis of the lens.
12. The electromagnetic lens assembly as claimed in claim 11 , wherein the flange portion has at least one notch, and an inner wall of the tube body of the lens barrel has at least one first positioning rib entering the at least one notch to restrict the lens from rotating.
13. The electromagnetic lens assembly as claimed in claim 12 , wherein the at least one first positioning rib includes two first positioning ribs respectively abut against two sides of the at least one notch; the protective cover has two second positioning ribs entering between the two first positioning ribs and respectively abutting against the two first positioning ribs.
14. The electromagnetic lens assembly as claimed in claim 11 , wherein an inner wall of the tube body has a plurality of supporting ribs constituting the shoulder portion; the protective cover has a plurality of abutting ribs constituting the abutting portion.
15. The electromagnetic lens assembly as claimed in claim 9 , wherein the second end of the lens barrel is an open end; the lens is located between the first end and the second end, and the emission surface faces the second end; an anti-ultraviolet coating is at least provided on the emission surface of the lens.