Patent Application
20240093858
The current application relates to lighting devices. More particularly, the current application is directed to an improved apparatus for optimizing light output from a lighting device.
Light emitting diodes (LEDs), and their inherent benefits, have become increasingly popular. LED devices use high power LEDs in order to use as few LEDs as possible to achieve a desired lumen output. Generally speaking, the higher the power pushed through the LED, the greater lumen output. But high power LEDs are reaching a technological limit on the amount of lumens that can be generated. In addition, high-output LEDs may each draw currents greater than is practical for packaged LED modules and dissipate more power than can be radiated or conducted away from the module efficiently. Since LED dies are packaged very small to minimize required board space, adequate heat removal is difficult. A common design is to mount high power LEDs on a flat, heat conductive substrate and provide a diffusive envelope around the substrate. Removing heat from such designs, using ambient air currents, is difficult since the LED may be mounted in any orientation. Metal fins or heavy metal heat sinks are common ways to remove heat from such systems, but such heat sinks add significant cost and have other drawbacks. It is desirable to have other methods of increasing the light output of a lighting device or the appearance of output from a lighting device.
The present technology will become more fully apparent from the following description and appended claims, taken in conjunction with the accompanying drawings. Understanding that these drawings merely depict examples of the present technology they are, therefore, not to be considered limiting of its scope. It will be readily appreciated that the components of the present technology, as generally described and illustrated in the figures herein, could be arranged and designed in a wide variety of different configurations. Nonetheless, the invention will be described and explained with additional specificity and detail through the use of the accompanying drawings in which:
Although the following detailed description contains many specifics for the purpose of illustration, a person of ordinary skill in the art will appreciate that many variations and alterations to the following details can be made and are considered to be included herein. Accordingly, the following embodiments are set forth without any loss of generality to, and without imposing limitations upon, any claims set forth. It is also to be understood that the terminology used herein is for the purpose of describing particular embodiments only, and is not intended to be limiting. Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this disclosure belongs.
As used in this specification and the appended claims, the singular forms “a,” “an” and “the” include plural referents unless the context clearly dictates otherwise. Thus, for example, reference to “a layer” includes a plurality of such layers.
In this disclosure, “comprises,” “comprising,” “containing” and “having” and the like can have the meaning ascribed to them in U.S. patent law and can mean “includes,” “including,” and the like, and are generally interpreted to be open ended terms. The terms “consisting of” or “consists of” are closed terms, and include only the components, structures, steps, or the like specifically listed in conjunction with such terms, as well as that which is in accordance with U.S. patent law. “Consisting essentially of” or “consists essentially of” have the meaning generally ascribed to them by U.S. patent law. In particular, such terms are generally closed terms, with the exception of allowing inclusion of additional items, materials, components, steps, or elements, that do not materially affect the basic and novel characteristics or function of the item(s) used in connection therewith. For example, trace elements present in a composition, but not affecting the compositions nature or characteristics would be permissible if present under the “consisting essentially of” language, even though not expressly recited in a list of items following such terminology. When using an open ended term, like “comprising” or “including,” it is understood that direct support should be afforded also to “consisting essentially of” language as well as “consisting of” language as if stated explicitly and vice versa.
The terms “first,” “second,” “third,” “fourth,” and the like in the description and in the claims, if any, are used for distinguishing between similar elements and not necessarily for describing a particular sequential or chronological order. It is to be understood that any terms so used are interchangeable under appropriate circumstances such that the embodiments described herein are, for example, capable of operation in sequences other than those illustrated or otherwise described herein. Similarly, if a method is described herein as comprising a series of steps, the order of such steps as presented herein is not necessarily the only order in which such steps may be performed, and certain of the stated steps may possibly be omitted and/or certain other steps not described herein may possibly be added to the method.
The terms “left,” “right,” “front,” “back,” “top,” “bottom,” “over,” “under,” and the like in the description and in the claims, if any, are used for descriptive purposes and not necessarily for describing permanent relative positions. It is to be understood that the terms so used are interchangeable under appropriate circumstances such that the embodiments described herein are, for example, capable of operation in other orientations than those illustrated or otherwise described herein. The term “coupled,” as used herein, is defined as directly or indirectly connected in an electrical or nonelectrical manner. Objects described herein as being “adjacent to” each other may be in physical contact with each other, in close proximity to each other, or in the same general region or area as each other, as appropriate for the context in which the phrase is used. Occurrences of the phrase “in one embodiment,” or “in one aspect,” herein do not necessarily all refer to the same embodiment or aspect.
As used herein, the term “substantially” refers to the complete or nearly complete extent or degree of an action, characteristic, property, state, structure, item, or result. For example, an object that is “substantially” enclosed would mean that the object is either completely enclosed or nearly completely enclosed. The exact allowable degree of deviation from absolute completeness may in some cases depend on the specific context. However, generally speaking the nearness of completion will be so as to have the same overall result as if absolute and total completion were obtained. The use of “substantially” is equally applicable when used in a negative connotation to refer to the complete or near complete lack of an action, characteristic, property, state, structure, item, or result. For example, a composition that is “substantially free of” particles would either completely lack particles, or so nearly completely lack particles that the effect would be the same as if it completely lacked particles. In other words, a composition that is “substantially free of” an ingredient or element may still actually contain such item as long as there is no measurable effect thereof.
As used herein, the term “about” is used to provide flexibility to a numerical range endpoint by providing that a given value may be “a little above” or “a little below” the endpoint. Unless otherwise stated, use of the term “about” in accordance with a specific number or numerical range should also be understood to provide support for such numerical terms or range without the term “about”. For example, for the sake of convenience and brevity, a numerical range of “about 50 angstroms to about 80 angstroms” should also be understood to provide support for the range of “50 angstroms to 80 angstroms.”
As used herein, a plurality of items, structural elements, compositional elements, and/or materials may be presented in a common list for convenience. However, these lists should be construed as though each member of the list is individually identified as a separate and unique member. Thus, no individual member of such list should be construed as a de facto equivalent of any other member of the same list solely based on their presentation in a common group without indications to the contrary.
Concentrations, amounts, and other numerical data may be expressed or presented herein in a range format. It is to be understood that such a range format is used merely for convenience and brevity and thus should be interpreted flexibly to include not only the numerical values explicitly recited as the limits of the range, but also to include all the individual numerical values or sub-ranges encompassed within that range as if each numerical value and sub-range is explicitly recited. As an illustration, a numerical range of “about 1 to about 5” should be interpreted to include not only the explicitly recited values of about 1 to about 5, but also include individual values and sub-ranges within the indicated range. Thus, included in this numerical range are individual values such as 2, 3, and 4 and sub-ranges such as from 1-3, from 2-4, and from 3-5, etc., as well as 1, 2, 3, 4, and 5, individually.
This same principle applies to ranges reciting only one numerical value as a minimum or a maximum. Furthermore, such an interpretation should apply regardless of the breadth of the range or the characteristics being described.
Reference throughout this specification to “an example” means that a particular feature, structure, or characteristic described in connection with the example is included in at least one embodiment. Thus, appearances of the phrases “in an example” in various places throughout this specification are not necessarily all referring to the same embodiment.
Reference in this specification may be made to devices, structures, systems, or methods that provide “improved” performance. It is to be understood that unless otherwise stated, such “improvement” is a measure of a benefit obtained based on a comparison to devices, structures, systems or methods in the prior art. Furthermore, it is to be understood that the degree of improved performance may vary between disclosed embodiments and that no equality or consistency in the amount, degree, or realization of improved performance is to be assumed as universally applicable.
An initial overview of technology embodiments is provided below and specific technology embodiments are then described in further detail. This initial summary is intended to aid readers in understanding the technology more quickly, but is not intended to identify key or essential features of the technology, nor is it intended to limit the scope of the claimed subject matter.
Broadly speaking, with general reference to
Thermal management can be a challenge especially with high power density LEDs. The luminous output of an LED or LED “Chip on Board” or “COB” is related to its temperature. A high temperature lowers the optical output power of an LED. The junction temperature in a LED is a function of the electrical power driven into the LED, the ratio of power turned into heat, and thermal resistance to heat dissipation. COBs are common when space is not constrained, so heat dissipation is traditionally less of a concern. COBs are also used in lighting devices with a fixed lens to cast a broad beam of light over an area. They have not been used in connection with a focusing or axially adjustable lens because the distributed source of light that accompanies a COB is not fully capture in an adjustable lens system, resulting in inefficiencies.
The primary factors affecting the thermal resistance of LEDs are its internal thermal resistance, the thermal resistance of electrical interconnections, the thermal resistance of any heat dissipating (heat sink) structures, and the heat convection capability of the LED's encapsulation. The sum of all thermal resistances in a component together with the thermal power or heat generated, defines how much the temperature rises in the component over the ambient temperature.
LEDs are assembled on a metal core printed circuit board (MCPCB), or on aluminum substrate, which is connected to a ceramic, plastic or aluminum heat sink. Ceramic heat sinks make it possible to use different thick film methods to manufacture the interconnections directly on top of the heat sink. Plastic heat sinks are used mainly with MCPCBs for relatively low power solutions. After the heat has been conducted through the thermal interfaces between the heat dissipating body and the PCB or MCPCB into its aluminum plate, further heat conduction is done from the bottom of the PCB, enhanced by different thermal interface materials and different fastening methods, e.g. screws. In many LED lighting applications, several high power LEDs need to be placed in close configuration. Such applications include, but are not limited to, spot lights, COB LED module structures, etc. The heat generating components, their power supplies, the PCBs, the thermal interface materials and solutions, the fixing structures and heat dissipating bodies, all together dictate the achievable performance level in the lighting application. The amount of lumens achievable from the application is a function of the heat transfer capacity of the structure.
In one aspect of the technology, a plurality of LEDs having a similar power rating or intensity, or a single high power LED, is disposed about a single substrate as part of an LED assembly and fixed in a lighting device, such as a flashlight. An axially moveable or adjustable lens is coupled to a distal end of the lighting device in the light path of the LED assembly. In another aspect of the technology, a perceived high-lumen output is achieved by mixing different intensity LEDs on the same substrate or chip forming an LED assembly. For purposes of the present disclosures, and in aspects of the technology, LED intensity is generally categorized by “high-power” LEDs, “mid-power” LEDs, and “low-power” LEDs. While there may be overlap between ranges, generally speaking, a high-power LED comprises a diode having an output ranging from 110 lumens/watt to 150 lumens/watt, a mid-power LED comprises a diode having an output ranging from 80 lumens/watt to 120 lumens/watt, and a lower-power LED comprises a diode having an output ranging from 50 lumens/watt to 100 lumens/watt. With reference generally to
In one aspect of the technology, different portions of a substrate can have different densities of LED assemblies. Meaning, a first portion may have a first density of LEDs and a second portion may have a second density of LEDs, where the first density is greater than the second density, though in one aspect of the technology the density of the LEDs is substantially consistent across the surface of the substrate. In one aspect, the power rating of the different LEDs may be the same or they may be different. In one aspect, the LEDs are COB LEDs and are placed within the void of an elongate handheld lighting device housing, with the LEDs oriented in a direction to propagate light in the axial direction of the elongate housing. In this aspect, an axially adjustable lens is placed at a distal end of the housing and operates to focus the light propagated from the COB LEDs.
In accordance with one aspect of the technology, an LED assembly comprises a sapphire substrate and includes at least an N type semiconductor layer, a semiconductor light emitting layer and a P type semiconductor layer, which are sequentially stacked. In one aspect, the N type semiconductor layer is an N type GaN (gallium nitride) layer, the semiconductor light emitting layer may consist of gallium nitride or indium gallium nitride, and the P type semiconductor layer is a P type GaN layer. Other substrates are contemplated for use herein, including thin film substrates, and other flexible polymer substrates. The P type semiconductor layer and the N type semiconductor layer are respectively connected to a positive end and a negative end of an external power source by at least one electrical connection line. A thermally conductive binding layer is used to bind the LED chip to the substrate. In general, the thermally conductive binding layer consists of silver paste, tin paste, copper-tin alloy or gold-tin alloy. A circuit layer is formed on the substrate and includes a circuit pattern. Electrical connection lines are used to connect the LED chip to the circuit layer. That is, the positive and negative ends of the LED chip are respectively connected to the positive and negative terminals of the circuit layer so as to supply power to the LED chip and activate the LED light. In one aspect, a fluorescent binder or coating is deposited directly on top of the LED chip to provide the effect of fluorescence. More specifically, the fluorescent binder can convert the original light generated by the LED chip into output light within the spectrum of visible light with a specific wavelength. For example, the original light with the spectrum of ultraviolet may be converted into substantially blue (425 to 450 nm) or substantially red (650 to 700 nm) light, or a mixture of different wavelengths. In one aspect of the technology, there is no fixed lens or cover placed over the binder. Rather, the binder 30 or coating is placed directly on top of the face of the LED such as that shown in
In aspects of the technology, portions of a single substrate are populated with high-power LEDs while other portions of the substrate are populated with LEDs that are lower powered (i.e., mid-power or low-power) than the high power LEDs forming a lighting assembly. A lens is disposed in front of (forward of the LED light emission pathway) the substrate or lighting assembly, wherein the axial distance between the lens and the lighting assembly is fixed or, in another aspect, is adjustable. In one aspect of the technology, the portion of the lighting assembly that comprises the high-power LEDs has a first fluorescent binder or coating and the portion of the lighting assembly with the lower powered chips has a second fluorescent binder. In one aspect of the technology, the composition of the first binder is different than the composition of the second binder. The combination of light emanating from the two different portions of the assembly through the different binders optimizes the total beam of light from the assembly. In one aspect of the technology, the high-power LEDs with a first binder are rated at between 6000 and 7000 CCT and the lower-powered section is rated at between 3500 and 4500 CCT. In order to differentiate the various hues of white, artificial light sources like LEDs are labeled with a correlated color temperature, or CCT. CCT is measured in degrees Kelvin (K), and this temperature rating indicates what tone of white light will be emitted from the fixture.
In other aspects of the technology, an adjustable lens is shaped to provide different focal lengths to the different portions of the light assembly. For example, portions of the light assembly having the high-powered LEDs may correspond to a portion of the lens configured to provide a focal length that is greater than a portion of the lens corresponding to the portions of the light assembly having mid or low-powered LEDs. Advantageously, the different focal lengths of the single lens corresponding to different portions of the light assembly with different powered LEDs creates a uniform beam of light at an optimized lumen value using less power and creating less heat to be dissipated by the light assembly. In another aspect of the technology, the lens may have a fixed portion and an adjustable portion, each portion corresponds to a different section of the substrate populated with different powered LEDs. In one aspect, a portion of the lens corresponding to the center of the substrate (e.g., center portion 51 shown on lens 50) is adjustable axially with respect to the direction of light propagated from the LEDs, a second portion of the lens (e.g., outer portion 52 on lens 50) corresponding with an outer portion of the substrate is fixed, though the opposite arrangement is also contemplated herein. Meaning, an inner portion may be fixed while the outer portion is moveable. In one aspect of the technology, the adjustable lens is associated with an LED assembly with LEDs having similar power ratings or intensities, the different shaped portions (e.g., lenses shown in
In aspects of the technology, the distribution or grouping of different powered LEDs varies as suits a particular design. For example, with reference to
A conventional LED has a plastic plano-convex dome placed on top of the LED itself to focus or spread the light. Typical spatial distribution (divergence characteristics) of light emitted from an LED is measured in degrees from a center point of the LED. For example, an LED may be rated at 115 degrees in both x and y directions (i.e., the beam will extend 57.5 degrees on either side). The light will be stronger the closer one is to the center. Along the center axis, the LED emits 100% of its relative luminous intensity and will lose intensity farther away from the center. An LED running at 350 mA, for example, rated at 139 lumens at the central axis will drop to 125 lumens at 30 degrees from center. This continues to drop until at 57.5 degrees one is only getting about half the lumen output at 70 lumens. In one aspect of the technology, optics are used to collimate the light rays into a controlled beam that will bring the greater light intensity to a desired area. In aspects of the technology, reflectors are used in connection with an internal lens. With LEDs, the majority of light rays coming from the center of the emitter may pass out of the system without even touching the reflector. This means that even with a narrow reflective system, a significant portion of the light strays wide of the target. This results in lost lumen output or creates an unwanted glare. In one aspect of the technology, an internal adjustable lens is used either alone or in connection with a reflector and is generally injection molded from a polymer and is used a refractive lens, by itself or inside a reflector. In other aspects of the technology, however, a LED assembly is used without a reflector.
Different LEDs have different patterns of light distribution which require collimation in order to be effective, whether used with a reflector or without a reflector. For example, in one aspect of the technology, an LED has a divergence of 38 degrees in x and 47 degrees in y. The focal length is given by the formula f=D/(2*tan(alpha/2)), where D is the desired beam diameter and alpha is the full beam divergence in the direction in question. For this example, for a desired beam diameter of 25 mm:
fx=25/(2_tan(38/2)=36 mm fy=25/(2_tan(47/2)=29 mm
A different LED may have different divergence characteristics resulting in a different focal length at the same desired beam diameter. A lens configured to optimize the focal lengths of the different LEDs (or LED assemblies) for the same desired beam diameter will advantageously optimize beam lumens while minimizing power consumption and heat production.
With reference to
It is also understood that the different LED configurations may be used with a conventional convex lens if that is desired by a person skilled in the art. For example,
With reference to
Support Components
In another aspect of the technology, the different zones of different LED configurations or different LED intensities allows for placement of different support components 80 on the substrate 20 that would otherwise be required to be placed on the different chip (e.g., power control chip, memory chip, or conventional printed or integrated circuit board. Placing the support components 80 on the substrate 20 amongst the LEDs 81 (see, e.g.,
Control Circuits
With reference to
With reference to
In accordance with one aspect of the technology, a method of propagating light from a portable lighting device is disclosed comprising providing power to an LED assembly, the LED assembly comprising a substrate and a plurality of LEDs disposed thereon. In one aspect of the technology, the plurality of LEDs comprises a first plurality of LEDs having a first power rating and a second plurality of LEDs having a second power rating and wherein a fluorescent binder is disposed about a top face of the first and second plurality of LEDs. The first plurality of LEDs propagates light from through a first portion of a lens disposed coaxially with the LED assembly to form a first beam of light having a first pattern. The second plurality of LEDs propagates light through a second portion of the lens to form a second beam of light having a second pattern. In one aspect of the technology, the first portion of the lens has a first focal length and the second portion of the lens has a second focal length, the first focal length being different than the second focal length. The method further comprises adjusting the distance between the lens and the LED assembly to adjust the pattern of the first beam of light and the second beam of light.
The foregoing detailed description describes the invention with reference to specific exemplary embodiments. However, it will be appreciated that various modifications and changes can be made without departing from the scope of the present invention as set forth in the appended claims. The detailed description and accompanying drawings are to be regarded as merely illustrative, rather than as restrictive, and all such modifications or changes, if any, are intended to fall within the scope of the present invention as described and set forth herein. Moreover, while different aspects of the technology or described individually, it is understood that different parts of the different aspects may be combined in any number of different configurations.
More specifically, while illustrative exemplary embodiments of the invention have been described herein, the present invention is not limited to these embodiments, but includes any and all embodiments having modifications, omissions, combinations (e.g., of aspects across various embodiments), adaptations and/or alterations as would be appreciated by those skilled in the art based on the foregoing detailed description. The limitations in the claims are to be interpreted broadly based on the language employed in the claims and not limited to examples described in the foregoing detailed description or during the prosecution of the application, which examples are to be construed as non-exclusive. For example, in the present disclosure, the term “preferably” is non-exclusive where it is intended to mean “preferably, but not limited to.” Any steps recited in any method or process claims may be executed in any order and are not limited to the order presented in the claims. Means-plus-function or step-plus-function limitations will only be employed where for a specific claim limitation all of the following conditions are present in that limitation: a) “means for” or “step for” is expressly recited; and b) a corresponding function is expressly recited. The structure, material or acts that support the means-plus-function are expressly recited in the description herein. Accordingly, the scope of the invention should be determined solely by the appended claims and their legal equivalents, rather than by the descriptions and examples given above.
This application claims priority as a continuation to U.S. Non-Provisional patent application Ser. No. 17/473,461 filed on Sep. 13, 2021, now issued as U.S. Pat. No. 11,821,609, and claims benefit to U.S. Non-Provisional patent application Ser. No. 16/569,958 filed on Sep. 13, 2019, now issued as U.S. Pat. No. 11,149,924, all of which are also entitled “System, Apparatus, and Methods for Adjustable Focal Length Light”, and all of which are incorporated herein by reference in their entirety.
| Number | Date | Country | |
|---|---|---|---|
| Parent | 17473461 | Sep 2021 | US |
| Child | 18514918 | US | |
| Parent | 16569958 | Sep 2019 | US |
| Child | 17473461 | US |
