Patent Application
20170038030
The present invention relates generally to a lighting fixture. In particular, the present invention relates reflective matte coating method for a lighting fixture.
A lighting fixture is designed to direct light to provide efficient illumination of objects or surface areas. An important component of the lighting fixture is a reflective surface, which may comprise a metal surface which provides directivity of the light produced by the light sources. The lighting fixture includes a base metal material which is typically coated with a reflective layer to provide visible light reflectivity at the surface and to protect the metal material from the environment.
The reflective layer is often applied as an adhesive film or as a single coating layer via a curing process. The use of thermal processes may result in a high gloss coating. Efficient total reflectivity and low gloss can be difficult to achieve with a single coating layer.
In light emitting diode (LED) applications, it is often desirable to achieve a low gloss (i.e., matte) coating in order to prevent the appearance of individual LED devices as reflected from the fixture surface. Therefore, in existing LED applications, implementation of thermal curing processes fails to result in a desired low gloss coating on the lighting fixture.
Given the foregoing deficiencies, a need exists for a highly reflective matte coating using an infrared (IR) gradient curing method for a lighting fixture.
In one exemplary embodiment, a lighting fixture is provided. The lighting fixture includes a metal layer including an inner surface and an outer surface; and a powder coating layer disposed on the outer surface of the metal layer, wherein an IR gradient curing operation is performed on the inner surface of the metal layer, to form a reflective matte coating at an external surface of the lighting fixture.
In another exemplary embodiment, a reflective matte coating on a metal layer is provided. The reflective matte coating includes a powder coating layer formed of reflective material disposed on an outer surface of a metal layer, wherein the powder coating layer is adhered to the metal layer by performing an IR gradient curing operation on an inner surface of the metal layer opposite the outer surface, to form the reflective matte coating on an external surface of the metal layer.
The foregoing has broadly outlined some of the aspects and features of various embodiments, which should be construed to be merely illustrative of various potential applications of the disclosure. Other beneficial results can be obtained by applying the disclosed information in a different manner or by combining various aspects of the disclosed embodiments. Accordingly, other aspects and a more comprehensive understanding may be obtained by referring to the detailed description of the exemplary embodiments taken in conjunction with the accompanying drawings, in addition to the scope defined by the claims.
The drawings are only for purposes of illustrating preferred embodiments and are not to be construed as limiting the disclosure. Given the following enabling description of the drawings, the novel aspects of the present disclosure should become evident to a person of ordinary skill in the art. This detailed description uses numerical and letter designations to refer to features in the drawings. Like or similar designations in the drawings and description have been used to refer to like or similar parts of embodiments of the invention.
As required, detailed embodiments are disclosed herein. It must be understood that the disclosed embodiments are merely exemplary of various and alternative forms. As used herein, the word “exemplary” is used expansively to refer to embodiments that serve as illustrations, specimens, models, or patterns. The figures are not necessarily to scale and some features may be exaggerated or minimized to show details of particular components. In other instances, well-known components, systems, materials, or methods that are known to those having ordinary skill in the art have not been described in detail in order to avoid obscuring the present disclosure. Therefore, specific structural and functional details disclosed herein are not to be interpreted as limiting, but merely as a basis for the claims and as a representative basis for teaching one skilled in the art.
Embodiments of the present invention provide a reflective matte coating to be applied to a metal layer (e.g., a metal layer of a lighting fixture) including a powder coating layer that includes a reflective material and a binder content, wherein a single side IR gradient curing operation is performed on the outer metal surface coated with the powder coating layer, to thereby form the reflective matte coating on an external surface of the lighting fixture. It may be implemented within various types of lighting fixtures to provide efficient illumination of display and surface areas.
The outer metal layer can be formed of any suitable material for the purpose set forth herein. The outer metal layer 20 includes an inner surface 22 and an outer surface 24. The reflective matte coating 100 is formed on the outer surface 24 of the outer metal layer 20 of the lighting fixture 10. The reflective matte coating 100 is a powder coating layer formed of particles 108 (e.g., pigment particles) and a binder 110. The reflective matte coating 100 includes a first surface 102 adhered to the outer surface 24 of the outer metal layer 20, and a second surface 104 forming the matte external surface of the lighting fixture 10.
The particles 108 can be formed of a material such as metal oxide inorganic particles (e.g., TiO2, Al2O3, Y2O3, ZrO2, Ta2O5, Nb2O5), mixed metal oxide particles (MMOs), complex inorganic color pigments (CICPs), inorganic metal particles (e.g., BN, SiC), or other inorganic pigments known for white or colored pigmentation of coatings, or combinations thereof. The particles can also be formed of triglycidyliocyanurate.
The particles 108 are reflective to light having wavelengths in a certain range. A single type of pigment particle 108 can be used to provide a color to the reflective matte coating layer 100 by reflecting certain wavelengths of light. The pigment particles 108 can be included in the reflective matte coating layer 100 based on its composition, particle size, and/or density for its reflective characteristics.
The binder 110 can be any cross-linked binder that includes at least one of a cross-linkable polymeric binder that interacts with a cross-linker to from a 3-dimensional polymeric structure. The cross-linkable binder can include any suitable cross-linkable material prior to cross-linking and can encompass monomers, oligomers, and copolymers which can be further processed to form cross-linking binders that include materials such as reactive carboxyl groups (e.g., acrylics and meth-acrylic, polyurethanes, and ethylene-acrylic acid copolymers, reactive hydroxyl groups (e.g., polyesters such as polyethylene terephthalate), and combinations of these materials or any other materials suitable for the purpose set forth herein.
During manufacturing, a sheet of metal material is used to form the outer metal layer 20 of the lighting fixture 10. An IR gradient curing process is performed on the inner surface 22 of the metal layer 20 (as depicted by the arrow in
The curing process can be performed at low temperatures ranging from approximately 100° C. or less. For example, the curing process may be performed at a range of approximately 75° C. to approximately 95° C. or higher. The curing process is performed for a duration ranging from approximately 5 minutes to approximately 2 hours, for example. However, the present invention is not limited hereto and the time may extend outside this range (i.e., less or greater). The curing operation can be performed in two operations, a first curing operation being performed at a temperature of approximately 75° C. to approximately 95° C. or higher for approximately 5 minutes to 2 hours, and a second curing operation being performed at a temperature of approximately 100° C. to approximately 150° C. or higher for approximately 5 minutes to 2 hours.
When the curing operation is performed, the outer metal layer 20 is directly heated from the inner side 22 thereof, causing gradient temperature from the inner surface 22 to the second surface 104 (e.g., outer external surface) of the reflective matte coating 100. Due to higher temperature at an interface of the outer surface 24 of the metal layer 20 and the first surface 102 of the reflective matte coating layer 100, more binder 110 flowing during crosslinking to enhance adhesion and due to lower temperature at the second surface 104 (e.g., the external surface), less binder 110 flowing during cross-linking, to thereby achieve a matte (e.g., low glossy) finish.
The reflective matte coating 100 can be formed of a thickness ranging from approximately 50 μm to approximately 250 μm. However, the present invention is not limited hereto and the thickness may vary, as needed.
As shown in
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From operation 410, the process continues to operation 420 where an IR gradient curing operation is performed on an inner surface of the outer metal layer of the lighting fixture, to adhere the powder coating layer to the outer metal layer and provide a reflective matte coating at the external surface of the lighting fixture.
Embodiments of the present invention provide the advantages of forming a reflective matte coating layer on a lighting fixture by performing an IR gradient curing operation on a single side of the outer metal layer of the lighting fixture. The embodiments provide advantages of more uniform temperature distribution due to high energy exposure on the thermal conductive substrate (e.g., the outer metal layer) and good surface finish.
This written description uses examples to disclose the invention, including the best mode, and also to enable any person skilled in the art to practice the invention, including making and using any devices or systems and performing any incorporated methods. The patentable scope of the invention is defined by the claims, and may include other examples that occur to those skilled in the art. Such other examples are intended to be within the scope of the claims if they have structural elements that do not differ from the literal language of the claims, or if they include equivalent structural elements with insubstantial differences from the literal languages of the claims.
