Patent Application
20130329411
The present disclosure relates to a focusing optic for shaping a beam of light from a light source, such as a light emitting diode (LED), for example in a flashlight or other lighting unit. In various embodiments, the lens may be combined with an adjustment mechanism for varying the focus of the beam of light.
Lenses for flashlights and other lighting units have been provided in a variety of forms, generally having in common a shape that is symmetrical about an axis along which the light is directed, e.g., the optical axis. Several such lenses have included a hole, such as a rear void, in the back side of the lens adjacent a light source. Within the hole, the light source may be adjusted in position along the optical axis. Adjustment of the light source's position relative to the rear hole of the lens enables variance of a light beam emerging from a front face of the lens. Typically, lenses are limited in their capacity to combine a maximum intensity for a spot beam with a substantial uniformity for a wide beam.
Such lenses typically also were provided with a central convex lens surface on a front face combined with at least one additional convex surface where the light was either received into the lens, reflected within the lens, or emitted from the lens. Without being bound by theory, the additional convex surface may have been deemed necessary for a proper focusing of light from the source into a beam. Such lenses were alternatively provided with light-receiving, reflecting, and emitting surfaces that were flat as viewed in cross-section. Such flat surfaces were also likely deemed necessary for light-focusing or manufacturing purposes.
Embodiments will be readily understood by the following detailed description in conjunction with the accompanying drawings. Embodiments are illustrated by way of example and not by way of limitation in the figures of the accompanying drawings.
In the following detailed description, reference is made to the accompanying drawings which form a part hereof, and in which are shown by way of illustration embodiments that may be practiced. It is to be understood that other embodiments may be utilized and structural or logical changes may be made without departing from the scope. Therefore, the following detailed description is not to be taken in a limiting sense, and the scope of embodiments is defined by the appended claims and their equivalents.
Various operations may be described as multiple discrete operations in turn, in a manner that may be helpful in understanding embodiments; however, the order of description should not be construed to imply that these operations are order dependent.
The description may use perspective-based descriptions such as up/down, back/front, and top/bottom. Such descriptions are merely used to facilitate the discussion and are not intended to restrict the application of disclosed embodiments.
The terms “coupled” and “connected,” along with their derivatives, may be used. It should be understood that these terms are not intended as synonyms for each other. Rather, in particular embodiments, “connected” may be used to indicate that two or more elements are in direct physical or electrical contact with each other. “Coupled” may mean that two or more elements are in direct physical or electrical contact. However, “coupled” may also mean that two or more elements are not in direct contact with each other, but yet still cooperate or interact with each other.
For the purposes of the description, a phrase in the form “A/B” or in the form “A and/or B” means (A), (B), or (A and B). For the purposes of the description, a phrase in the form “at least one of A, B, and C” means (A), (B), (C), (A and B), (A and C), (B and C), or (A, B and C). For the purposes of the description, a phrase in the form “(A)B” means (B) or (AB) that is, A is an optional element.
The description may use the terms “embodiment” or “embodiments,” which may each refer to one or more of the same or different embodiments. Furthermore, the terms “comprising,” “including,” “having,” and the like, as used with respect to embodiments, are synonymous.
Embodiments herein provide focusing optics for flashlights and other lighting devices. In some embodiments, a focusing optic as disclosed herein may be combined with a light source and an adjustment mechanism that allows focusing of the light from the source. In various embodiments, a light emitting diode or LED may be used as the light source, although other light sources, such as incandescent or fluorescent bulbs may be used.
In various embodiments, the lens may be generally circular, and may have a front face configured to emit light and a rear face configured to receive light from the light source. In various embodiments, the lens may be shaped to direct light from the light source in a desired direction, and may have a generally concave front face and a generally convex rear face, although portions of the front face may also be convex, and portions of the back face may be concave.
In various embodiments, the lens may include two or more distinct portions, such as a central portion surrounded by an annular ring, and the curvature of each of these two portions may vary independently of one another, depending on the desired beam-shaping properties of the lens and other factors. In various embodiments, the central portion may include a central focusing element, and in some embodiments, the central focusing element may be set off from the annular ring portion by a side wall that is configured to form a rear void in the rear face of the lens. In various embodiments, the central focusing element, side wall, and annular ring may be a single piece, whereas in other embodiments, the central portion and the annular ring portion may be separate components. In various embodiments, the rear void formed by the central focusing element and side wall may be sized and shaped to accommodate a light source and/or at least of a portion of the light source base or pedestal.
The annular ring portion may be generally curved, and in various embodiments, a surface, such as a front or rear surface of the annular ring portion may be coated with a reflective coating and configured to function as a reflector. In other embodiments, particularly when the lens is a two-part lens, the annular ring portion may be made from a separate piece of the same material, or a different material than the central portion, for example, an injection-molded, vacuum-metalized polycarbonate plastic, acrylate polymer, or acrylic, a metallic material, such as machined aluminum, or any other material having reflective properties. Although the examples illustrated herein depict single-piece focusing lenses and two-part lenses wherein the central portion includes the central focusing element and the side wall, one of skill in the art will appreciate that in other embodiments, the central focusing element may be separate from the rest of the lens, which may include the side wall and annular ring portions, or a three-part lens may be used.
In some embodiments, outside of the central focusing element, the thickness of the lens may vary very little in the different areas. In various embodiments, the thickest portion of the lens may be the central focusing element, which may be several times thicker than the surrounding lens portions in order to disperse the light in a wide beam when the light source is spaced closely behind the lens, within the rear void. In some embodiments, the thickness of this central focusing element may be varied in order to achieve a desired beam focusing effect. In various embodiments, outside the central focusing element, the rest of the lens may have a relatively uniform thickness, varying in thickness from about 0% to about 20% across the lens surface, such as about 18%, about 15%, about 12%, about 10%, about 9%, about 8%, about 7%, about 6%, about 5%, about 4%, about 3%, about 2%, or about 1%. Without being bound by theory, it is believed that the thin profile of the disclosed lenses permits a more efficient transfer of light through the lens as compared to conventional lenses, and may enable a lower-powered light source to be used to achieve a beam with equivalent or greater brightness as compared to conventional flashlight lenses. Furthermore, for single-piece embodiments, the one-piece construction may simplify assembly steps and thereby reduce the cost required to produce the light. In other embodiments, for example, a two-piece lens may be used in order to simplify machining or metalizing of the reflector, or to reduce manufacturing costs compared to those associated with a single-piece system. In a two-piece lens system, the annular ring portion may have a profile with a thickness dimension similar to that of the side wall portion, or it may be thicker or thinner, depending on the application.
In some embodiments, the lens may be housed in a flashlight bezel, which may couple to or form a portion of a body or housing member. In some embodiments, the body or housing member may include a light source fixably coupled thereto, and the bezel may be adjustable, for example by sliding or twisting, with respect to the body or housing member. In some embodiments, this slidable or twistable adjustability may permit alteration of the distance between lens and light source, thus allowing the light beam to be adjusted from flood or wide bean to spot or narrow beam. In particular embodiments, the bezel may be adapted to couple to a body member that includes the LED fixed thereupon. In these embodiments, the distance between the lens and the LED may be adjusted by virtue of adjusting the position of the bezel on the body member, for instance via a threaded coupling or one or more O-rings. In other embodiments, the position of the light source may be adjustable within the body or bezel, and the system may include an adjustment mechanism for moving the light source relative to the lens, such as a switch, tab and slot, or any other mechanism known to those of skill in the art.
In some embodiments, the annular ring portion may define in cross-section an elliptical curve, and may include a light-reflecting surface, which may be configured to reflect the light that strikes it from within the lens body. In various embodiments, the annular ring portion, viewed internally of the lens body as a reflector, may define in cross-section a concave curve. In other embodiments, the annular ring portion viewed from outside the lens body may define a convex curve. In still other embodiments, the annular ring portion may be flat, when viewed in cross section.
In various embodiments, the central focusing element may include a front surface that may be convex, and so may include a forward-most point, typically at the center of the surface. In various embodiments, the annular ring portion of the front face of the lens body may extend forward to a front rim that is farther forward than the forward-most point of the front surface of the central portion, thus protecting the lens body from impact and abrasion. The lens body may further include an outer, front rim defining a chamfer between the annular surface and the side surface.
In various embodiments, the flashlight also may include a power supply, such as batteries or an AC-DC converter with electronics to condition a voltage waveform compatible with the LED. For example, in some embodiments, a pulse width modulator may be used to adjust the effective brightness of the LED.
In various embodiments, the lens body (or just the central portion, in some embodiments) may be formed from a single piece of solid, transparent material, such as glass, an acrylate polymer such as polymethyl methacrylate (PMMA), or a thermoplastic polymer, such as a polycarbonate plastic, molded or otherwise formed as a single piece. In some embodiments, the lens or central portion may be formed from a single piece of solid, injection-molded acrylic. In some embodiments, the central portion of the lens may be co-molded with the annular ring portion of the lens. In further embodiments, the lens may be co-molded with other parts, such as all or part of the bezel. Optionally, some portions of this integrated piece may be tinted or coated, for example with a light-reflecting or obstructing coating, and/or portions of the bezel may be painted or otherwise tinted to prevent light escape. In still other embodiments, the central portion of the lens, including the central focusing element and the side wall, may be formed from a transparent material, such as glass, an acrylate polymer such as PMMA, a thermoplastic polymer such as polycarbonate plastic, or injection-molded acrylic, and the annular ring portion may be formed from a reflective material, such as injection-molded, vacuum-metalized polycarbonate plastic, acrylate polymer, or acrylic, or from a metal, such as machined aluminum. In these embodiments, although the central portion and the annular ring portion are separate components, they may be configured to mate together and they may not move relative to one another during focusing of the light.
In various embodiments, central portion 106 includes a central focusing element 110, which may be configured to direct light in a desired direction. In various embodiments, central focusing element 110 may include a convex front surface 112 and a flat rear surface 114, although in other embodiments, rear surface 114 may be flat or convex, depending on the desired focusing properties of the lens. In various embodiments, central focusing element 110 may be set off from annular ring portion 108 by a side wall 116 that may be configured to form a rear void 118 in the rear face 104 of the lens. In various embodiments, rear void 118 may be sized and shaped to accommodate a light source and/or at least of a portion of the light source base or pedestal (not shown). In various embodiments, side wall 116 may be flat as illustrated in
In various embodiments, annular ring portion 108 may have a reflective front or back surface, and may be shaped in order to reflect light from the light source in a desired direction. In various embodiments, as described in greater detail below, central focusing element 110, side wall 116, and annular ring portion 108 may be configured to cooperate to direct light from a light source in a desired direction. Although a particular configuration of lens components is illustrated in
Additionally, although lens body 100 includes slight concavities and/or convexities in various portions, one of skill in the art will appreciate that the overall lens shape includes a generally concave front face 102, a generally convex rear face 104, a central focusing element 110, a side wall 116 configured to form a rear void 118, and an annular ring portion 108 configured to function as a reflector. Although the illustrated embodiment depicts central focusing element 110 as being continuous with side wall 116, one of skill in the art will appreciate that in other embodiments these features may be partially or completely discontinuous. In various embodiments, the overall thickness of the lens body 100, excluding central focusing element 110, when seen in cross section, is fairly uniform throughout lens body 100, despite being adapted to bend in and out of plane in order to achieve a desired focusing effect. In various embodiments, the thickness (T) of lens body 100, excluding central focusing element 110, may vary less than about 20% (for example, 15%, 10%, 5%, or 2%) over the entire width of lens body 100. For example, in one specific, non-limiting example, the thickness may vary by less than about 10% over the full width of lens body 100, excluding central focusing element 110, for example, 9%, 8%, 7%, 6%, 5%, 4%, 3%. 2%, 1%, or even 0%. In specific, non-limiting embodiments, a suitable lens thickness for a small-diameter lens may be about 2-3 mm, and a suitable thickness for a large-diameter lens may be 2-3 cm, or even more. In general, thickness (T) may be measured across a lens body in a direction generally perpendicular to any position on a front surface of the lens body, excluding the central focusing element.
In various embodiments, central portion 106 may include a convex front surface 112 defining a forward-most point. In various embodiments, convex front surface 112 may incorporate any of various curvatures, and in some embodiments, the curvature may be substantially arcuate with a radius of no more than about 4 mm for a small-diameter flashlight having an overall lens diameter of less than about 2 cm, for example a lens having an overall diameter of about 12 mm. One of skill in the art will appreciate that this central portion diameter may be generally proportionately larger for larger diameter lenses. For example, a large diameter lens of 5-10 cm may have a central portion having a diameter of 1-4 cm, for example about 1.5-2.5 cm. The measurements described with reference to the embodiments of the lens are merely exemplary. Those of ordinary skill in the art will readily understand that other measurements may be used without deviating from the scope of the disclosure.
In various embodiments, annular ring portion 108 of lens body 100 may extend forward to front rim 124. In various embodiments, front rim 124 may extend farther forward than the forward-most point of central portion 106. In various embodiments, front rim 124 may include a chamfer between annular ring portion 108 and front rim 124 of at least about 0.2-0.5 mm of width for a small diameter flashlight. In some embodiments, the chamfer may have a width selected for a desired lens size and operational characteristics, and, as examples only, may be about 1.5 mm, about 2.0 mm, about 2.5 mm, or about 3.0 mm in width for a larger diameter lens.
In one specific, non-limiting example of a lens, e.g., for a small-sized lens system, the lens may have a width of about 8 mm, a thickness of about 2 mm, an inner diameter of about 3 mm, a chamfer width of about 1 mm, and a range of position adjustment of about 2 mm. Other combinations may be selected for desired operational characteristics and lens sizes. Typically such dimensional ratios may be varied by at least about ±10%.
In various embodiments, central focusing element 210 may interact with LED 226 in various manners dependent upon, for example, the position of LED 226. For instance, in various embodiments, when LED 226 is far away from central focusing element 210 (e.g., a narrow angle position), only a small fraction of the light may interact with central focusing element 210. Consequently, in various embodiments, central focusing element 210 may not noticeably influence narrow light distribution. Conversely, when LED 226 is near to rear surface 214 of central focusing element 210 (e.g., a wide angle position), central focusing element 210 may influence the beam pattern in a desired manner. Thus, in various embodiments, central focusing element 210 may enable wide angle light distribution, with little effect on narrow angle distribution. Thus, in various embodiments where LED 226 is in a forward position (e.g., within rear void 218 and close to rear surface 214 of central focusing element 210), the bulk of the light from LED 226 will pass through central focusing element 210, and will be directed in a wide beam pattern.
Conversely, in various embodiments when LED 226 is in a rearward position (e.g., toward the back of rear void 218 and spaced apart from rear surface 214 of rear void 218), only a small portion of the light from LED 226 will pass through central focusing element 210. Instead, light from LED 226 will pass through side wall 216, and it will reflect off of the reflective surface of annular ring portion 208 to be directed in a desired direction, for example in a narrow or spot beam.
This phenomenon is illustrated in
In other embodiments, as shown in
In various embodiments, body member 430a, 430b may include a heat sink member 436a, 436b adapted to disperse heat from the LED. In some embodiments, heat sink member 436a, 436b may be shaped to fit closely within rear void 418. Without being bound by theory, it is believed that maximizing the size of heat sink member 436a, 436b within rear void 418 may allow for better heat transfer away from LED 426a, 426b. In particular embodiments, at least a portion of heat sink member 436a, 436b may be frustoconical.
In various embodiments, the system may be adjusted with the adjustment mechanism as described in order to provide a light beam with a wide beam having a distribution with an angular range of about +/−45° over which the intensity is at least 50% of the maximum or on-axis value. For that wide beam, the system may provide a substantially uniform intensity between at least about +/−10° of angular distribution.
In some embodiments, bezel 428a, 428b may be provided with a grip-enhanced region, such as a region having grooves, ridges, swellings, textures, or the like, which may extend partially or completely around bezel 428a, 428b. In various embodiments, the grip-enhanced region may aid a user, e.g., in a one-handed adjustment of the focus of the beam by providing a convenient grip for the thumb and forefinger on bezel 428a, 428b while body member 430a, 430b is gripped by the other three fingers. In some embodiments, a control button may be provided on the flashlight body, e.g., at an end opposite bezel 428a, 428b, or on bezel 428a, 428b itself.
In various embodiments, body member 426a, 426b or other housing structures may be made from a metal such as aluminum or steel or a plastic such as ABS. Component materials may be selected to be compatible with lighting unit operation in harsh environments such as very high or very low ambient temperatures.
As is true with the single-piece lens, in the illustrated two-piece lens embodiment, central portion 606 may include a central focusing element 610, which may be configured to direct light in a desired direction. As may be best seen in
In various embodiments, annular ring portion 608 may have a reflective front or back surface, and may be shaped in order to reflect light from light source 626 in a desired direction. In various embodiments, as described in greater detail above, central focusing element 610, side wall 616, and annular ring portion 608 may be configured to cooperate to direct light from a light source in a desired direction.
As described above, in various embodiments, the overall thickness of the lens body 600, excluding central focusing element 610, when seen in cross section, may be fairly uniform throughout lens body 600, despite being adapted to bend in and out of plane in order to achieve a desired focusing effect. In some embodiments, such as in the illustrated embodiment, side wall 616 and annular ring portion 608 may have similar thickness dimensions, and in other embodiments, annular ring portion 608 may be thicker or thinner than side wall 616, depending on the application and the materials selected. Additionally, although central portion 610 and annular ring portion 608 are illustrated as having a particular size ratio relative to one another, one of skill in the art will appreciate that the diameters of the central portion and annular ring portion 608 may be varied in order to suit a particular application. For example, central portion 610 may be paired with a narrow annular ring portion 610 in a small diameter flashlight, and it may be paired with a much larger diameter annular ring portion in a large diameter flashlight.
Although certain embodiments have been illustrated and described herein, it will be appreciated by those of ordinary skill in the art that a wide variety of alternate and/or equivalent embodiments or implementations calculated to achieve the same purposes may be substituted for the embodiments shown and described without departing from the scope. Those with skill in the art will readily appreciate that embodiments may be implemented in a very wide variety of ways. This application is intended to cover any adaptations or variations of the embodiments discussed herein. Therefore, it is manifestly intended that embodiments be limited only by the claims and the equivalents thereof.
The present application is a continuation-in-part of U.S. patent application Ser. No. 13/490,278, filed Jun. 6, 2012, titled “FOCUSING OPTIC FOR FLASHLIGHT,” the entire specification of which is hereby incorporated by reference in its entirety for all purposes, except those sections, if any, that are inconsistent with this specification.
| Number | Date | Country | |
|---|---|---|---|
| Parent | 13490278 | Jun 2012 | US |
| Child | 13710820 | US |
