US 12,094,326 B2
Lens for a visual alarm detector
Kenneth J. Mott, Colorado Springs, CO (US); Narval Danvers, Denver, CO (US); and Ryan Kelley, Denver, CO (US)
Assigned to CARRIER CORPORATION, Palm Beach Gardens, FL (US)
Appl. No. 17/042,643
Filed by Carrier Corporation, Palm Beach Gardens, FL (US)
PCT Filed Mar. 29, 2019, PCT No. PCT/US2019/024907
§ 371(c)(1), (2) Date Sep. 28, 2020,
PCT Pub. No. WO2019/191631, PCT Pub. Date Oct. 3, 2019.
Claims priority of provisional application 62/650,848, filed on Mar. 30, 2018.
Prior Publication US 2021/0035419 A1, Feb. 4, 2021
Int. Cl. G08B 5/36 (2006.01); G02B 3/00 (2006.01); G02B 19/00 (2006.01); G02B 27/00 (2006.01)
CPC G08B 5/36 (2013.01) [G02B 3/00 (2013.01); G02B 19/00 (2013.01); G02B 27/00 (2013.01)] 16 Claims
OG exemplary drawing
 
1. A lens for covering an array of light emitting diodes (LED) mounted to a printed circuit board (PCB) in a visual alarm device (VAD), the lens being a dome lens extending upwardly in an axial direction about a center axis and outwardly in a radial direction, the lens comprising:
a first portion which is a bottom portion, the first portion forming a first annular ring about the center axis, the first portion including a first inner surface and a first outer surface, wherein the first portion is oriented so that a first tangent to the first inner surface is at a first angle to the center axis, wherein the first angle is less than forty-five degrees,
a second portion which is an intermediate portion, the second portion being continuous with the first portion, the second portion forming a second annular ring about the center axis, the second portion including a second inner surface and a second outer surface, wherein the second portion is oriented so that a second tangent to the second inner surface is canted toward the center axis,
a third portion which is a top portion that is continuous with the second portion to enclose the lens, the third portion forming an annular solid disk about the center axis, the third portion including a third inner surface and a third outer surface,
wherein:
the first inner surface, the second inner surface and the third inner surface together form a lens composite inner surface that is aberration-free, continuous and aspheric;
the first outer surface, the second outer surface and the third outer surface are each convex and together form a lens composite outer surface that, from the first outer surface to the third outer surface, is an aberration-free and continuously convex dome, wherein the third outer surface defines a hemispherical shape; and
the lens includes a fourth portion which is a base portion that extends axially below the first portion, the fourth portion being cylindrical and having a fourth outer surface that is continuous with, and has a same outer diameter as, the first outer surface, and
a fourth inner surface that extends downwardly from the bottom surface of the first portion, wherein the fourth inner surface and the bottom surface are configured to be positioned against the PCB; and
wherein the lens is thickest along the bottom surface of the first portion; and
wherein the lens is thinnest at a first interface between the second portion and the third portion; and
wherein the lens continuously increases in thickness in the second portion between the first interface and a second interface between the first portion and the second portion; and
wherein the lens is positioned against the PCB, with a LED element in the LED array having a height HL and the LED array having a diameter of DL:
a first height H1 of the first portion is 0.75*HL<H1<3*HL,
a second height H2 of the second portion is 3*HL<H2<5*HL,
a first diameter D1 of the first portion is 1.25*DL<D1<2*DL,
a second diameter D2 at the second interface is DL<D2<1.5*DL,
a third diameter D3 at the first interface is 0.5*DL<D3<DL.