The present invention relates generally to optic assemblies for automotive rearview mirrors. More particularly, the present invention relates to an improved optic assembly and method of manufacturing the assembly using selective metallization.
An automotive rearview mirror needs to provide certain visual information to a driver, while at the same time, not causing a disturbance to the driver or passengers, or to those in other vehicles travelling nearby. Some examples of existing automotive rearview mirrors and optic assemblies used for illuminating lighted features are shown in U.S. Pat. No. 8,708,536, which is incorporated herein by reference for all purposes. It is desirable for optic assemblies used in rearview mirrors to be as light and as small as possible, and to use as few LEDs or light sources as necessary. To reduce the number of light sources used, light rays from a light source in the optic assembly are reflected and directed by a reflector or reflectors in the optic assembly to direct light through apertures to illuminate the lighted features or manage light as otherwise desired. Reflectors used in the optic assembly can be angled, flat, stepped, curved or otherwise shaped to direct and orient light emitted from the light source. These angles, flats, curves or other shapes that form the topography of the reflective surface are referred to as “facets” by the inventors.
As automobile designers and manufacturers continue to desire smaller and thinner optic assemblies, a need exists for better light reflection control in optic assemblies used with rearview mirrors and other mirror assemblies. Small, thin reflectors are desirable because they offer lower weight, and a smaller form factor, thereby reducing the overall size and weight of the automotive mirror. With thin reflectors with shallow facets, it becomes more difficult to control the light in the optic assembly, and thus the amount of “stray light,” that is, light emitted in undesired or less than ideal directions. Manufactures also need increasingly efficient ways to manufacture complex and small optic assemblies to meet the specifications of automobile designer and manufacturers.
By using selective reflection in an optic assembly in an automotive rearview mirror, the light control challenges inherent in thin reflectors can be reduced. This enables more light control to be built directly into the reflector, such that additional light control elements, such as light control screens, are no longer needed to control stray light. Selective reflection is applied to the reflector in a selective metallization process using a mask to cover portions of the reflector that should not be metallized, and allowing metallization of the portions of the reflector that should be metallized. The process is efficient and cost effective and allows very effective improvement of light control to meet the desires of automobile designers and manufacturers for smaller, thinner, optic assemblies.
An automotive rearview mirror assembly includes a housing, a mirror mounted within the housing, an optic assembly mounted behind the mirror for lighting an illuminated feature, the optic assembly including a light source within the assembly, and a reflector, the reflector having an interior surface comprising a plurality of facets for managing the direction of light, and a reflective layer is selectively applied to the interior surface of the reflector.
An optic assembly for lighting an illuminated feature in an automotive rearview mirror assembly includes a reflector, the reflector having an interior surface, a light source emitting light into the interior surface of the reflector, the interior surface of the reflector including means for managing light rays emitted into the reflector to minimize stray light, and wherein the interior surface is selectively reflective to provide desired light control in dim zones and bright zones for viewing the illuminated feature.
A method of manufacturing an optic assembly for an automotive rearview mirror assembly including a reflector with a plurality of facets, the method including the steps of identifying a light source and reflector shape to provide desired luminescence for an illuminated feature in an automotive rearview mirror assembly, identify the facets of the reflector to apply a reflective layer to provide the desired luminescence of the illuminated feature in dim zones and in bright zones, prepare a mask assembly to selectively cover facets and expose other facets that will receive the reflective layer, apply a reflective layer using a metallizing process, and wherein the method results in metallized areas and non-metallized areas of the reflector to provide desired luminescence without the use of a light control screen or other light control elements.
It will be understood by those skilled in the art that one or more aspects of this invention can meet certain objectives, while one or more other aspects can lead to certain other objectives. Other objects, features, benefits and advantages of the present invention will be apparent in this summary and descriptions of the disclosed embodiments, and will be readily apparent to those skilled in the art. Such objects, features, benefits and advantages will be apparent from the above as taken in conjunction with the accompanying figures and all reasonable inferences to be drawn therefrom.
a,
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b, and 7c illustrate selective reflection as accomplished by selective metallization in a series of views of a reflector for an optic assembly for a lighted BSDD feature.
a,
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b, and 8c illustrate selective reflection as accomplished by selective metallization in a series of views of an optic assembly for a lighted turn signal feature in the left hand side rearview mirror assembly on an automobile.
a is an isometric view of an embodiment of a mask for use with an injection molded reflector.
a,
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b, and 12c are a series of illustrations showing the benefits of selective reflection and selective metallization in an optic assembly.
The present invention will be particularly useful in the context of optic assemblies used in rearview mirrors in the automotive industry, but will also be useful in other contexts for other assemblies with illuminated features, for example in industrial, construction, farm vehicles, residential and commercial lighting, and in other machines or equipment.
As noted above, automotive rearview mirrors must provide certain visual information to a driver, while at the same time, not causing a disturbance to the driver or passengers, or to those in other vehicles travelling nearby.
The inventors have invented improved optic assemblies that address and solve the challenges described above by using an optic assembly with selective reflection, manufactured using a selective metallization process.
The metallization process used may be any suitable metallization process, for example, a vacuum deposition process. Vacuum deposition is a family of processes used to deposit layers of material on a solid surface. These processes operate at pressures well below atmospheric pressure (vacuum) and the deposited layers can range from a thickness of one atom up to several millimeters. Thermal evaporation is a common method of thin-film deposition. The source material is evaporated in a vacuum, the vacuum allows vapor particles to travel directly to the target object (substrate), where they condense back to a solid state. One example of a vacuum deposition process may include: a polycarbonate substrate (without a base coat); followed by aluminum vacuum metallization; further followed by an in-chamber top coat. As another example, the process could include: an ABS substrate; an enamel base coat; aluminum vacuum metallization; followed by an enamel top coat. Other metallization processes may be used as well within the scope of the invention.
Selective metallization according to this disclosure is especially beneficial when it is applied to a thin reflector with shallow facets. Such thin reflectors are beneficial, for they offer lower weight, and a smaller form factor, thereby reducing the overall size and weight of the automotive mirror. With thin reflectors with shallow facets, it becomes more difficult to control the direction of any reflected light and manage stray light, but with the selective metallization process of this disclosure, the amount of stray light is significantly reduced. This has been found to be especially true and selective metallization especially effective with thin reflectors of less than 10 millimeters in depth, and even more so with reflectors of less than 7 millimeters in depth.
Further, by using selective reflection in an automotive rearview mirror reflector, the light control problems inherent in thin reflectors can be reduced, without the need to resort to other light control elements, such as light control screens, which increase the depth of the reflector package. Since these additional elements are no longer needed, this reduces the number of parts and the overall reflector depth required to obtain the desired light pattern. Fewer parts mean lower cost, and this provides a commercial advantage. And without the need to add a light control screen between a reflector and the outer transparent layer, the reflector may even be sealed directly to the transparent layer. An additional benefit of selective reflection is that optic assemblies or reflectors employing selective reflection require less plastic parts or multi-injection, and perhaps less or simpler faceting on the interior surface of the reflector.
Another example of selective reflection in a different illuminated feature is shown in
To accomplish this selective reflection, a mask 90 is used during manufacturing of the optic assemblies to selectively metalize the reflector or other components of the optic assembly, resulting in metallized areas and non-metallized areas. As an example of a mask 90 can be seen in
a and 11b illustrate another embodiment of mask 99 and also illustrate a method of manufacturing a reflector 95 for a BSDD illuminated feature, the reflector 95 including an interior surface 96 with a plurality of facets 97, and a layer of reflective material 98 applied to less than all of the surface areas on the interior surface 96. More particularly, a method of selectively metallizing two reflectors 95 at once is shown. A mask 99 is created that selectively covers certain covered surface areas 100 of each of the reflectors 95, the covered surface areas being those that should not be metallized. Mask 99 is shown in
As shown in
In one embodiment, the reflector 95 is formed by injection molding a non-reflective material, such as a black plastic, such as ABS (Acrylonitrile butadiene styrene) or PC (polycarbonate) material. But in other embodiments, any means of forming the base is within the scope of this disclosure. For example, other materials could be used, such as wood or metal, and other methods of creating the desired surface areas, such as by machining or by carving, are within the scope of this disclosure. In the illustrated embodiments, the various surface areas constitute facets which extend at various angles relative to a longitudinal axis of the reflector base, thereby creating various possible light reflection directions. In order to permit light reflection in some but not all directions, only selected surface areas have a layer of applied reflective material.
In a BSDD application, for example, selective metallization is deployed to achieve a high level of display luminance and acceptable appearance including uniformity in the direction of the driver's viewing angle (for example 40°-75°) while significantly attenuating the display luminance at the adjacent lane angles (for example 120° or higher). The selective metallization works in conjunction with the reflector being injection molded with a non-reflective material; typically a black thermoplastic like ABS or PC.
The process of selective metallization involves analysis of the optic capabilities and reflective capabilities of a given reflector and light source. Light source and reflector shape are identified as well as the desired luminescence characteristics for the particular application and lighted feature. Covered surface areas and exposed surface areas of the reflector must be identified as those will become the metallized and non-metallized areas of the reflector. A mask may be designed and used during the metallization process for the reflector. The materials for a metalized layer are selected and the metallized layer is applied to the reflector, thereby metallizing some areas of the reflector, but not others.
a,
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b, and 12c are a series of illustrations showing the benefits of selective reflection and selective metallization in an optic assembly.
b shows the same reflector 57 as in
c shows the improvement in accordance with the present invention, including a reflector 57 for the same lighted feature, but employing selective reflection and selective metallization to manage light, and in which the light control film is not necessary. A selectively metallized surface is denoted with reference number 106 in
Although the invention has been herein described in what is perceived to be the most practical and preferred embodiments, it is to be understood that the invention is not intended to be limited to the specific embodiments set forth above. Rather, it is recognized that modifications may be made by one of skill in the art of the invention without departing from the spirit or intent of the invention and, therefore, the invention is to be taken as including all reasonable equivalents to the subject matter of the appended claims and the description of the invention herein.
This application claims the benefit of U.S. Provisional Patent Application Ser. No. 62/037,837, filed Aug. 15, 2014, the disclosure of which is herby incorporated by reference in its entirety for all purposes.
Number | Date | Country | |
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62037837 | Aug 2014 | US |