Method of attaching a diffuser to an illuminated sign

The invention relates generally to illuminated signs (100) having multiple point light sources such as light emitting diode arrays as the illumination source for legend-bearing face panels and particularly to diffuser structure mountable in relation to such an array for facilitating an even distribution of light within such a sign to improve illumination of the typically translucent legend disposed on such a face panel. In particular, the invention employs a clear diffuser holder (120) that is secured to the inside surface of el the face panel thereby providing a means of removeably attaching a diffuser (130). The invention permits interchangeably employing diffusers of different colors while providing resistance to vandalism.

FIELD OF THE INVENTION

The invention relates generally to illuminated signs having multiple point light sources such as light emitting diode arrays as the illumination source for legend-bearing face panels and particularly to a diffuser structure mountable in relation to such an array for facilitating an even distribution of light within such a sign to improve illumination of the typically translucent legend disposed on such a face panel. In particular, the invention employs a clear diffuser holder that is secured to the inside surface of the face panel thereby providing a means of removeably attaching a diffuser. The invention permits interchangeably employing diffusers of different colors while providing resistance to vandalism.

BACKGROUND

Illuminated signs and particularly exit signs are commonly employed in commercial and industrial situations as well as in multi-unit residential buildings primarily for exit identification. Such signage takes many forms with interior illumination being provided through the use of a variety of illumination sources, an illumination source of particular utility in these energy conscious times being light emitting diodes which require greatly reduced power expenditures for operation. In order to overcome the low light generating capability of presently available light emitting diodes, various approaches have evolved including the use of a relatively large number of spaced apart light emitting diodes in various arrangements or arrays for providing the necessary candle power for satisfactory illumination of the interior of an exit sign such that the legends on face walls of such signs are evenly illuminated according to code requirements or any other reasonable standard of acceptability. Such arrangements typically use a diffuser material that is placed between the light emitting diodes and the legend sheet or plate. Such an illumination sign is described in U.S. Pat. No. 6,152,581, hereby incorporated by reference.

The present invention intends improvement upon the prior art by providing a diffuser holder arrangement which permits diffusers of different colors to be interchangeable positioned in the illuminated sign. Further, the diffuser holder arrangement of the present invention helps prevent vandalism to such an illuminated sign by precluding the insertion of foreign objects or other types of tampering.

SUMMARY OF THE INVENTION

In various embodiments of the present invention, a clear diffuser holder is formed which possesses a 180° return at two of its opposite edges. The diffuser holder is secured to the inside surface of the legend-bearing face panel of an illuminated sign. Such an illuminated sign is typically employed as an exit sign and thus the face panel or stencil typically says “EXIT.” In the discussion below, the phrases “EXIT sign” and “EXIT” stencil will be employed for simplicity although the invention is not so limited, as other types of illuminated signs are contemplated by the invention.

In various embodiments of the invention, the clear diffuser holder is typically formed of plastic and may be attached to the EXIT stencil by mechanical means such as fasteners or by heat staking plastic pins that are molded as part of the EXIT stencil where they pass thru holes in the clear diffuser holder. The clear diffuser holder provides a means of attachment for the red or green diffuser sheet and also provides resistance to vandalism. That is, by way of example, the red or green diffuser sheet cannot be pushed into the product from outside the product. The 180° return edges engage with the edges of a colored diffuser sheet, which is typically red or green in color. In this manner, the colored diffuser sheet is held tight against the inside surface of the clear diffuser holder.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS

While this invention is susceptible of embodiment in many different forms, there are shown in the drawings and will herein be described in detail one or more specific embodiments, with the understanding that the present disclosure is to be considered as exemplary of the principles of the invention and not intended to limit the invention to the specific embodiments shown and described.

In the following, for the sake of understanding, elements of embodiments are described in operation. However, it will be apparent that the respective elements are arranged to perform the functions being described as performed by them.

Further, the invention is not limited to the embodiments, and the invention lies in each and every novel feature or combination of features described herein or recited in mutually different dependent claims.

FIG.1Ashows an illuminated sign100in accordance with one embodiment of the present invention.FIG.1Bshows an exploded perspective view illustrating the primary components of the illuminated exit sign100. These components include a separate and removable diffuser holder120and a diffuser sheet130. In various embodiments of the invention, the diffuser holder is formed from clear plastic, while the diffuser sheet would be colored (e.g., red or green). The diffuser holder120is tightly attached to the EXIT stencil110by mechanical means such as fasteners or by heat staking plastic pins (not illustrated) that are molded as part of the EXIT stencil. In the embodiment illustrated inFIG.1B, these staking means mate with pass-thru holes140in the diffuser holder120. Once assembled, the diffuser holder120provides a means of attachment of the diffuser sheet130to the illuminated sign100. That is, as depicted inFIG.1B, the 180° return edges of the diffuser holder120form channels150that engage two opposing edges of the diffuser sheet130. In this manner, the diffuser sheet130is held tight against the inside surface of the clear diffuser holder120.

It should be noted that the diffuser holder120also provides resistance to vandalism. That is, as the diffuser holder is securely attached to the inside of the stencil face, it prevents foreign objects from being pushed through the character “openings” in the stencil and into the interior of the sign—as such foreign objects are precluded from passing through or around the diffuser holder.

FIGS.2A-2Cillustrate various perspective views and corresponding dimensions of an exemplary diffuser holder according to the invention. As illustrated, the diffuser holder is 11.00″ long and 6.33″ wide, which width included opposed channels each being 0.150″ wide. In a preferred embodiment of the invention, the actual channel openings provide a gap of 0.030″ to accommodate insertion and secure retention of a diffuser sheet having a thickness of 0.018″. These dimensions are not limiting. That is, by way of further examples, diffuser sheets are typically 0.010″ to 0.030″ thick and made of rigid materials like polycarbonate sheet. Thus, in additional embodiments, a channel gap opening would be provided with the appropriate size gap to accommodate insertion of the thickness of the diffuser sheets to be employed.

In additional embodiments of the invention, the face panel of the illuminated sign does not contain a stencil. Rather it comprises a transparent or translucent, solid cover. In these embodiments, the wording or indicia typically found on the stencil is instead provided on the diffuser sheet which is to be inserted into the diffuser holder. Accordingly, the wording/indicia displayed on the sign can be readily changed (e.g., the word “EXIT” can be changed to “SALIDA”). In such embodiments, the solid cover can also function as a diffuser. Further, the solid cover and/or the diffuser sheet can provide color to the output of the illuminated sign.

The foregoing detailed description has set forth a few of the many forms that the invention can take. The above examples are merely illustrative of several possible embodiments of various aspects of the present invention, wherein equivalent alterations and/or modifications will occur to others skilled in the art upon reading and understanding of the present invention and the annexed drawings. In particular, regard to the various functions performed by the above described components (devices, systems, and the like), the terms (including a reference to a “means”) used to describe such components are intended to correspond, unless otherwise indicated to any component, such as hardware or combinations thereof, which performs the specified function of the described component (i.e., that is functionally equivalent), even though not structurally equivalent to the disclosed structure which performs the function in the illustrated implementations of the disclosure.

Although a particular feature of the present invention may have been illustrated and/or described with respect to only one of several implementations, such feature may be combined with one or more other features of the other implementations as may be desired and advantageous for any given or particular application. Furthermore, references to singular components or items are intended, unless otherwise specified, to encompass two or more such components or items.