Patent Application
20130343036
The following description is provided to assist the understanding of the reader. None of the information provided or references cited is admitted to be prior art.
Light Emitting Diodes (LEDs) have recently surpassed 100 lumen/Watt (lm/W) efficacy and, as such, are now around 7 times as efficient as incandescent lamps and about 2 to 3 times as efficient as compact fluorescent lamps. LEDs, therefore, are now a viable option for use in many applications to replace former light sources.
Refrigeration and freezer units can use incandescent lamps or compact fluorescent lamps. To attract consumers' attention, products stored in refrigeration or freezer units need to be clearly visible. Lighting and transparent doors are ways that ensure the products are illuminated. Lighting typically consists of a light source located within the refrigeration units that are separate from the door. The light source, therefore, operates independently from the door, and the opening and closing of the door has little to no impact on how the encased products are illuminated.
The present invention relates to a door of a refrigeration or freezer unit that illuminates products within a refrigeration unit without creating glare when the door is either opened or closed.
An illustrative refrigeration unit door includes a light source, a window portion, and a plurality of uniformly-sized prisms that are non-uniformly spaced. The window portion receives light from the light source at a first face and the light exhibits total internal reflection in the window portion. The plurality of prisms ejects light from a second face of the window portion at angles between 10 and 80 degrees.
An illustrative process of manufacturing a refrigeration unit door comprises attaching a light source to the refrigeration unit door. The light source emits light to a first face of a window portion and the light exhibits total internal reflection within the window portion. A plurality of uniformly-sized prisms that are non-uniformly spaced are affixed to the window portion. The prisms eject light from a second face of the window portion at angles between 10 and 80 degrees.
The foregoing summary is illustrative only and is not intended to be in any way limiting. In addition to the illustrative aspects, embodiments, and features described above, further aspects, embodiments, and features will become apparent by reference to the following drawings and the detailed description.
The foregoing and other features of the present disclosure will become more fully apparent from the following description and appended claims, taken in conjunction with the accompanying drawings. Understanding that these drawings depict only several embodiments in accordance with the disclosure and are, therefore, not to be considered limiting of its scope, the disclosure will be described with additional specificity and detail through use of the accompanying drawings.
In the following detailed description, reference is made to the accompanying drawings, which form a part hereof. In the drawings, similar symbols typically identify similar components, unless context dictates otherwise. The illustrative embodiments described in the detailed description, drawings, and claims are not meant to be limiting. Other embodiments may be utilized, and other changes may be made, without departing from the spirit or scope of the subject matter presented here. It will be readily understood that the aspects of the present disclosure, as generally described herein, and illustrated in the figures, can be arranged, substituted, combined, and designed in a wide variety of different configurations, all of which are explicitly contemplated and made part of this disclosure.
Described herein are illustrative illuminating doors for use in refrigeration and/or freezer units. The term refrigeration unit is used interchangeably with freezer unit. In an illustrative embodiment, a refrigeration door includes multiple light sources, for example light-emitting diodes (LEDs), which provide light to a transparent window pane of the refrigeration door. The light sources can be located at any of the edges of the window pane. Upon entering the window portion, the light exhibits total internal reflection, such that the light stays within the window pane.
Because the light stays within the window pane due to total internal reflection, to provide lighting or additional lighting to products within the refrigeration unit, the light from the light sources must be ejected toward the interior of the refrigeration unit. An illustrative way of achieving this is by attaching a thin film containing a number of uniformly-sized prisms to the window pane. In an exemplarily embodiment, the prisms are between 20 to 30 micrometers in size. While prisms can provide a way to eject the light, the angle of the ejected light is important. To avoid unwanted glare or light being ejected onto the person opening the door, the light should be ejected at an angle that is not perpendicular to the open door. In an exemplarily embodiment, 90/30/60 prisms are used to eject light at around a 60-degree angle for light traveling in a first direction and at around a 30-degree angle for light traveling in a second direction. The second direction is substantially opposite to the first direction. In one embodiment, 95% of the ejected light that was traveling in the first direction is ejected from the prisms at an angle of 60 degrees plus or minus 2 degrees. In this embodiment, 95% of the ejected light that was traveling in the second direction is ejected from the prisms at an angle of 30 degrees plus or minus 2 degrees. In other embodiments, other angles of ejection are possible such as 10 degrees, 20 degrees, 45 degrees, 75 degrees, 80 degrees, etc.
The light loses intensity as it travels in the first direction through the window pane away from the light source as a result of some of the light being ejected by the prisms. To achieve uniform lighting, the prisms are non-uniformly spaced. The prisms are spaced closer to one another as the prisms get farther away from the light source. This ensures that the light ejected from the window pane is relatively uniform along the entire window pane.
Any light that is not ejected during a first pass through the window pane can be reflected back into the pane using a reflective material that coats the edge of the window pane opposite the light sources. Light that is reflected back, in the second direction, into the window pane also needs to be ejected at some non-perpendicular angle. In the exemplarily embodiment using the 90/30/60 prisms, the reflected light can be ejected at around a 30-degree angle.
In an illustrative embodiment, an open refrigeration unit door ejects light into the refrigeration unit. To avoid an unwanted glare seen by consumers passing an open door, the amount of light ejected from the window pane away from the refrigeration unit should be minimized or eliminated. Thus, the prisms are configured to eject light into the refrigeration unit, but not away from the refrigeration unit. In an exemplary embodiment, collimated light is used to minimize the amount of light ejected away from the refrigeration unit. For instance, a collimated light to +/−15 degrees significantly reduces the amount of light ejected away from the refrigeration unit. In one embodiment a collimator is operably coupled between the LED light source and the input edge of the pane. The collimator further collimates the light, which reduces the amount of light ejected away from the refrigeration unit. In one embodiment, the collimator collimates the light to +/−7 degrees.
The window pane can also include an anti-reflective coating on one or both sides of the window pane. The anti-reflective coating reduces or eliminates visible streaks than can be created by the multiple light sources when an anti-reflective coating is not used.
In another embodiment, the window pane comprises three panes of glass or other suitable transparent material. The LED light source can enter any of these panes. The thin film of prisms can be operably connected to any of the panes that include an LED light source. In some embodiments, the different panes provide insulation and anti-fogging properties. In one embodiment, the anti-reflective coating can be added to an innermost interior pane and the LED light source can enter the middle pane. A second anti-reflective coating can be applied between the innermost interior and middle panes to further reduce reflection and unwanted glare.
Additional details and embodiments are described with reference to the figures.
In another embodiment, a substrate layer (not shown) can be included that is between the window pane 108 and the prism portion 104. The substrate layer can be used to achieve total internal reflection of the light from a light source 106 within the window pane 108.
A light source 106 provides light that will be ejected by the prisms 102a and 102b. As
In embodiments using multiple light sources, the light sources can be placed along any edge of the door 100. For instance, the light sources can be at the top, bottom, left, or right side of the door 100. Based upon the location of the light sources, the prisms 102a and 102b can be positioned vertically or horizontally along the door 100. In embodiments using a single light source, the light source can be located near any corner of the door 100. The steps can be located along any of the edges of the door 100 based upon the location of the single light source.
The door 100 of
The spacing of prisms illustrated in
In addition to the various refrigeration door embodiments described above, one of skill in the art would recognize numerous other applications of the above disclosed invention. For example, a troffer can incorporate a prism portion that directs light at various angles to minimize glare on surfaces such as a CRT screen. In another embodiment, a window can include a prism portion that provides an indirect lighting source. For example, an exterior window can include a layer of prisms that ejects light, such as light from the sun, into an interior at particular angles, such as 60 degrees. In one embodiment, the prisms are configured such that the light is ejected toward a particular portion of the interior, such as, but not limited to, the floor, walls, the ceiling, the center of the room, an object within the room, etc. In one embodiment, the prisms do not eject light at a common angle. Instead, the prisms can eject light out at different angles, such that the light is focused onto a particular area of the interior. In yet another embodiment, a prism portion can be used in a reach-in refrigeration case to illuminate products contained therein.
With respect to the use of substantially any plural and/or singular terms herein, those having skill in the art can translate from the plural to the singular and/or from the singular to the plural as is appropriate to the context and/or application. The various singular/plural permutations may be expressly set forth herein for the sake of clarity.
It will be understood by those within the art that, in general, terms used herein, and especially in the appended claims (e.g., bodies of the appended claims) are generally intended as “open” terms (e.g., the term “including” should be interpreted as “including but not limited to,” the term “having” should be interpreted as “having at least,” the term “includes” should be interpreted as “includes but is not limited to,” etc.). It will be further understood by those within the art that if a specific number of an introduced claim recitation is intended, such an intent will be explicitly recited in the claim, and in the absence of such recitation no such intent is present. For example, as an aid to understanding, the following appended claims may contain usage of the introductory phrases “at least one” and “one or more” to introduce claim recitations. However, the use of such phrases should not be construed to imply that the introduction of a claim recitation by the indefinite articles “a” or “an” limits any particular claim containing such introduced claim recitation to inventions containing only one such recitation, even when the same claim includes the introductory phrases “one or more” or “at least one” and indefinite articles such as “a” or “an” (e.g., “a” and/or “an” should typically be interpreted to mean “at least one” or “one or more”); the same holds true for the use of definite articles used to introduce claim recitations. In addition, even if a specific number of an introduced claim recitation is explicitly recited, those skilled in the art will recognize that such recitation should typically be interpreted to mean at least the recited number (e.g., the bare recitation of “two recitations,” without other modifiers, typically means at least two recitations, or two or more recitations). Furthermore, in those instances where a convention analogous to “at least one of A, B, and C, etc.” is used, in general such a construction is intended in the sense one having skill in the art would understand the convention (e.g., “a system having at least one of A, B, and C” would include but not be limited to systems that have A alone, B alone, C alone, A and B together, A and C together, B and C together, and/or A, B, and C together, etc.). In those instances where a convention analogous to “at least one of A, B, or C, etc.” is used, in general such a construction is intended in the sense one having skill in the art would understand the convention (e.g., “a system having at least one of A, B, or C” would include but not be limited to systems that have A alone, B alone, C alone, A and B together, A and C together, B and C together, and/or A, B, and C together, etc.). It will be further understood by those within the art that virtually any disjunctive word and/or phrase presenting two or more alternative terms, whether in the description, claims, or drawings, should be understood to contemplate the possibilities of including one of the terms, either of the terms, or both terms. For example, the phrase “A or B” will be understood to include the possibilities of “A” or “B” or “A and B.”
The foregoing description of illustrative embodiments has been presented for purposes of illustration and of description. It is not intended to be exhaustive or limiting with respect to the precise form disclosed, and modifications and variations are possible in light of the above teachings or may be acquired from practice of the disclosed embodiments. It is intended that the scope of the invention be defined by the claims appended hereto and their equivalents.
This application claims the benefit of U.S. Provisional Application No. 61/479,266, filed Apr. 26, 2011.
| Filing Document | Filing Date | Country | Kind | 371c Date |
|---|---|---|---|---|
| PCT/US2012/034834 | 4/24/2012 | WO | 00 | 9/13/2013 |
| Number | Date | Country | |
|---|---|---|---|
| 61479266 | Apr 2011 | US |
