Patent Application
20140268879
1. Field of the Disclosure
The present invention generally relates to light waveguide diffusers for illuminating environments or objects and methods of manufacturing light waveguide diffusers.
2. Background Information
Light sources used for illumination typically require waveguides to transfer light from the light sources to diffusing points and diffusers to diffuse or to spread out or to scatter the light to produce soft light, which generally cast shadows with no edges or soft edges as opposed to sharp edges. For example, in photography, soft light is used to reduce visibility of wrinkles for people to achieve a more youthful look.
Typical diffusers are hazy in appearance, or the diffusers are opaque or non-transparent. That is, an observer cannot see objects clearly through a typical diffuser. Typical diffusers may include for example, ground glass diffusers, Teflon diffusers, holographic diffusers, opal glass diffusers, and greyed glass diffusers. Because such diffusers are not transparent, their presence in the view of observers may seem distracting and unpleasant. Additionally, typical diffusers may scatter significant amounts of light back toward the light source, and thus, efficiency of the light source is reduced when such typical diffusers are used.
In one example, the dots 15 may be printed onto the panel 10 by an ink jet printer, screen printing techniques, or any other ink printer. The dots may also be rolled, splattered, or sprayed onto the panel 10. The dots in any of the embodiments described herein can be formed by any of these processes, unless specifically stated otherwise.
The present disclosure, through one or more of its various aspects, embodiments, and/or specific features or sub-components, provides various device, apparatus, or structures that can achieve the transparent waveguide diffuser, as well as method that can be used to manufacture the transparent waveguide diffuser.
In one embodiment of the disclosure, there is a waveguide light diffuser panel coupled to a light source, including a first surface that is of low reflection to a plurality of wavelengths of light; and a second surface having diffusive dots, wherein visible light from the light source is transmitted through the waveguide light diffuser panel, and at least a portion of the visible light from the light source is reflected from the inkjet dots on the second surface and transmitted through the first surface.
In one aspect of the disclosure, the diffusive dots are one of micro-lenses, micro-dots and micro-bumps formed by one of molding, embossing, screen printing, and inkjet printing.
In another aspect of the disclosure, the diffusive dots cover 20-50% of the waveguide diffuser panel surface
In still another aspect of the disclosure, the diffusive dots are distributed on the waveguide light diffuser panel in a grid array in one of a sparse, staggered, random, semi-random, and interleaved arrangement.
In yet one aspect of the disclosure, a period of the diffusive dots is enlarged or reduced.
In yet another aspect of the disclosure, shape of the dots is configurable into variable designs.
In one more aspect of the disclosure, the waveguide light diffuser panel is transparent.
In still another aspect of the disclosure, the waveguide light source is an LED.
In one aspect of the disclosure, the first surface is coated with a single or multi-layer anti-reflective coating.
In another aspect of the disclosure, the waveguide light diffuser panel has a concave shape causing divergent reflection of the visible light.
In yet one more aspect of the disclosure, the light source is mounted on at least one location on an edge of the waveguide light diffuser panel and configured to transmit the plurality of wavelengths of light into the waveguide light diffuser panel.
In another embodiment of the disclosure, there is a waveguide light diffuser panel coupled to a light source, including a first surface that has a concave shape causing divergent reflection of visible light; and a second surface having diffusive dots, wherein the visible light from the light source is transmitted through the waveguide light diffuser panel, and at least a portion of the visible light from the light source is reflected from the inkjet dots on the second surface and divergently transmitted through the second surface after at least partially reflecting off of the first surface.
In still another embodiment of the disclosure, there is a method of manufacturing a waveguide light diffusing panel coupled to a light source, including preparing a first surface that is of low reflection to a plurality of wavelengths of light; and preparing a second surface having diffusive dots, wherein visible light from the light source is configured to be transmitted through the waveguide light diffuser panel, and at least a portion of the visible light from the light source is configured to be reflected from the inkjet dots on the second surface and transmitted through the first surface.
In yet another embodiment of the disclosure, there is a light fixture having a waveguide diffusing panel coupled to a light source, including the light waveguide diffusing panel according to the first described embodiment.
The present invention is further described in the detailed description which follows, in reference to the noted plurality of drawings, by way of non-limiting examples of preferred embodiments of the present invention, in which like characters represent like elements throughout the several views of the drawings.
The present disclosure, through one or more of its various aspects, embodiments and/or specific features or sub-components, is thus intended to bring out one or more of the advantages as specifically noted below.
A transparent waveguide light diffuser panel is disclosed in which the panel diffuses source lights and transmits ambient light. Conventional waveguide light diffusers diffuse all light and therefore provide a hazy outcome. In manufacturing a transparent waveguide diffuser, a printing method, such as inkjet printing, screen printing techniques or any other ink printing, may be used. In this method, micro-lenses in the form of dots are printed on one side of a panel, which micro-lenses cover at least a portion of the panel in a variety of arrangements. For example, the dots may cover between 20%-50% of the panel (it is appreciated that the dot coverage range is not limited to 20%-50 and may extend beyond these ranges in either direction), and arranged in a sparse, staggered, random, semi-random, interleaved or any other pattern. The other side of the panel is coated with an anti-reflective material (or multiple layers of material), or the shape of the panel may be formed to diffuse, converge or diverge light. For example, the panel may be in a concave shape. However, the disclosure is not limited to a concave shape as understood by the skilled artisan. The dot shape and size is designed for efficient reflection of the incident light, as opposed to conventional hazy diffusers in which the reflection efficiency is low. High reflection efficiency in this case compensates for the reduced dot coverage.
Manufacturing using inkjet based printing is typically based on a grid positioning method. Using this method, inkjet dots are deposited on an imaginary grid on a panel. Depositing dots using this method introduces a Talbot image, which is a periodic image of the micro-lenses formed by the dots. Unfortunately, the Talbot image disturbs the appearance quality of the light.
The waveguide light diffuser panel 10 may be integrated with a light emitting element or light source 20 on one edge of the waveguide diffuser panel 10. The light source 20 may be for example, a LED (light emitting diode), laser diode and SLD (super luminescent diode), or coupling optics such as collection lens, collimator, and beam shaper, etc. which transmit light generated from a source of light. The light source 20 may be mounted or bonded on one edge of the waveguide light diffuser panel 10, for example by mechanical mounting structures, chemical adhesives, heating, or a combination of such mounting methods. The light source 20 may be, for example, designed to direct light of one or more visible wavelengths into the waveguide light diffuser panel 10 from one edge, at one or more oblique angles relative to the plane of the waveguide light diffuser panel 10, or at one or more angles that are greater than the total internal reflection (TIR) angle or critical angle of the waveguide light diffuser panel 10.
In this configuration, the light transmitted by the light source 20 into the waveguide light diffuser panel 10 will be waveguided and diffused from generally the entire surface of waveguide light diffuser panel 10, as noted above, to illuminate objects on both sides of the panel via bi-directional illumination. As also noted above, the illuminated objects would be clearly visible when viewed through the waveguide light diffuser panel 10. This provides a transparent waveguide light diffuser that can provide higher efficiency of lighting and a more pleasant transparent view.
As explained, the light source resulting in the Talbot image is the reflection of light from the front-side of the waveguide light diffuser panel 10. This reflection may be reduced or eliminated, for example, using a regular anti-reflective (AR) coating or material. The following are examples of coating techniques that may be applied to the front-side of the panel.
(1) Regular single film AR coating:
A coating with a refractive index of in, where √n is the panel index. For example, a panel formed of acrylic has an index of about 1.51 for most visible light range. Accordingly, the index of the AR coating material for the acrylic panel should be √1.51≈1.23.
(2) Multi-layer coating: Multiple coatings are used to coat the panel. Exemplary coatings include SiO2, TiO2 and ZrO2. It is appreciated that the coatings are not limited to the described embodiments, which are for exemplary purposes.
(3) Sub-wavelength periodic structure surface:
Instead of using a regular AR coating, the front surface of the panel 10 is embossed or imprinted with holes or bumps to avoid or significantly reduce reflection. The holes or bumps, in one embodiment, are sub-wavelength holes and bumps. That is, if the structure period is smaller than λ, where λ is the maximum wavelength of the light source (e.g. LED) spectrum, reflection does not occur for visible light.
When the dot period is small, the resultant Talbot image period is also small. Accordingly, by making the Talbot image small, the individual dot images overlap with each other and eventually become homogenized to create a uniform Talbot image (as illustrated, for example, in
Although the invention has been described with reference to several exemplary embodiments, it is understood that the words that have been used are words of description and illustration, rather than words of limitation. Changes may be made within the purview of the appended claims, as presently stated and as amended, without departing from the scope and spirit of the invention in its aspects. Although the invention has been described with reference to particular means, materials and embodiments, the invention is not intended to be limited to the particulars disclosed; rather the invention extends to all functionally equivalent structures, methods, and uses such as are within the scope of the appended claims.
Although the present specification describes components and functions that may be implemented in particular embodiments with reference to particular standards and protocols, the disclosure is not limited to such standards and protocols. Such standards are periodically superseded by faster or more efficient equivalents having essentially the same functions. Accordingly, replacement standards and protocols having the same or similar functions are considered equivalents thereof.
The illustrations of the embodiments described herein are intended to provide a general understanding of the various embodiments. The illustrations are not intended to serve as a complete description of all of the elements and features of apparatus and systems that utilize the structures or methods described herein. In this regard, no attempt is made to show structural details of the present invention in more detail than is necessary for the fundamental understanding of the present invention. Many other embodiments may be apparent to those of skill in the art upon reviewing the disclosure. Other embodiments may be utilized and derived from the disclosure, such that structural and logical substitutions and changes may be made without departing from the scope of the disclosure. Additionally, the illustrations are merely representational and may not be drawn to scale. Certain proportions within the illustrations may be exaggerated, while other proportions may be minimized. Accordingly, the disclosure and the figures are to be regarded as illustrative rather than restrictive.
One or more embodiments of the disclosure may be referred to herein, individually and/or collectively, by the term “invention” merely for convenience and without intending to voluntarily limit the scope of this application to any particular invention or inventive concept. Moreover, although specific embodiments have been illustrated and described herein, it should be appreciated that any subsequent arrangement designed to achieve the same or similar purpose may be substituted for the specific embodiments shown. This disclosure is intended to cover any and all subsequent adaptations or variations of various embodiments. Combinations of the above embodiments, and other embodiments not specifically described herein, will be apparent to those of skill in the art upon reviewing the description.
The Abstract of the Disclosure is provided to comply with 37 C.F.R. §1.72(b) and is submitted with the understanding that it will not be used to interpret or limit the scope or meaning of the claims. In addition, in the foregoing Detailed Description, various features may be grouped together or described in a single embodiment for the purpose of streamlining the disclosure. This disclosure is not to be interpreted as reflecting an intention that the claimed embodiments require more features than are expressly recited in each claim. Rather, as the following claims reflect, inventive subject matter may be directed to less than all of the features of any of the disclosed embodiments. Thus, the following claims are incorporated into the Detailed Description, with each claim standing on its own as defining separately claimed subject matter.
The above disclosed subject matter is to be considered illustrative, and not restrictive, and the appended claims are intended to cover all such modifications, enhancements, and other embodiments which fall within the true spirit and scope of the present disclosure. Thus, to the maximum extent allowed by law, the scope of the present disclosure is to be determined by the broadest permissible interpretation of the following claims and their equivalents, and shall not be restricted or limited by the foregoing detailed description.
