Illumination – Revolving
Reexamination Certificate
2000-01-10
2001-04-17
Tso, Laura K. (Department: 2875)
Illumination
Revolving
Reexamination Certificate
active
06217186
ABSTRACT:
This application is the national phase under 35 U.S.C. §371 of PCT International Application No. PCT/AU97/00650 which has an International filing date of Sep. 26, 1997 which designated the United States of America.
1. Background of the Invention
The present invention relates to display systems and more particularly relates to an illuminated display system which utilises a matrix of half tone arrays.
2. Prior Art
Australian patent 647834 by Ashall discloses a display system which comprises at least one transparent sheet having two opposing surfaces wherein at least one of these surfaces has a matrix of dots applied to the surface. That specification clearly indicates a preference that both surfaces which are to be illuminated be adapted with a matrix of dots applied to the respective surfaces to achieve the appropriate degree of refraction and reflection along the sheet from the light source to the point on the sheet most remote from the light source.
This patent specification sets out a table which compares the parameters of sign size, distance from the light source that the light from the illumination source must travel and a light meter reading (lux) taken midway between the light source and the end of the display sign most distant from the light source with the light meter readings being dependent upon whether one or both sides of the sheet is adapted with the matrix of dots. It is clear from the table in that patent specification that the two sided embodiment of the application of the dot matrix is preferred and indeed is indicated as providing more light particularly midway from the light source. This phenomenon is repeated as the area of the sheet increases and as the distance from the light source that the light must travel increases.
For larger sheet sizes where the light must travel a greater distance from the source, the light meter readings are lower but clearly the light intensity is greater when a two sided matrix is used.
SUMMARY AND OBJECTS OF THE INVENTION
The inventor has found that it is possible to dramatically increase the light intensity emanating from a sign or the like by using a particular form of matrix applied on one surface of a sheet of material which forms the sign compared with the light intensity emanating from an identical sized sheet having a dot matrix applied to both of two opposite sides of the sheet. This means that the sign can be produced more cheaply and with less material whilst at the same time the light intensity is increased by at least 50% in comparison to a sheet forming a sign of substantially like size with a dot matrix pattern applied to two opposing surfaces of the sheet.
It is an object of the invention to provide an illuminated sign wherein the sign comprises a sheet of transparent material such as glass or perspex which when a half tone array is applied to one surface and in the presence of a light source emits light at a greater intensity in comparison to that which would be emitted by a sign of the same or substantially the same size with a dot matrix applied to at least two surfaces of the sheet.
In its broadest form, the present invention comprises:
an illuminated display assembly comprising; a transparent sheet of material such as an acrylic comprising;
at least one surface forming at least one edge of the sheet and first and second outer surfaces, separated by said at least one surface,
a light source which delivers light via said at least one edge surface through and along the plane of the sheet and intermediate the outer surfaces; wherein, at least one of said outer surfaces has applied thereto at least one half tone translucent array arranged so as to distribute the light from said light source across said at least one or both surfaces of the sheet wherein said at least one half tone array covers a substantial part of the entire first or second surfaces with the remainder of the surface free of said array thereby increasing the intensity of light issuing from the display particularly in the region remote from the light source to at least fifty percent more than the light which issues by comparison from a display of like or substantially the same dimensions incorporating a dot matrix.
In another form the present invention comprises;
an illuminated display system comprising; a transparent sheet of material such as an
acrylic, including first and second outer surfaces;
a light source which delivers light along the plane of the sheet and between the outer surfaces via an edge surface of the sheet; wherein one of said outer surfaces has at least one half tone translucent array arranged on said surface so as to distribute the light across said first or second surfaces of the sheet; wherein said at least one half tone array covers a part of the entire surface of said first or second outer surfaces with the remaining part including a region free of half tones thereby increasing the intensity of light issuing from the display in the region remote from the free region compared to that which would issue from the same region were a dot matrix array used.
Preferably the light is evenly distributed across the outer surface. According to a preferred embodiment the display system is manufactured utilizing an acrylic sheet which is sandwiched between two outer layers which carry some form of message to be illuminated. The display system includes a light source and a support means for attaching the display system to a support structure. The light shines through the thickness dimension of the acrylic sheet along the plane of the material which has two large faces through which light from the light source is reflected via the matrix of half tone translucent arrays. The half tone matrix is arranged in such a way that the light is evenly distributed over the outer surface area of the acrylic sheet. The half tone arrays are not dots as described in patent 647834 previously mentioned. The referenced prior art document does not teach that it is possible to place a matrix of half tone translucent arrays on one side of the sheet to actually increase the light intensity compared to the dot matrix described on two sides of the sheet.
Preferably the half tone array covers a substantially part of the entire first and/or second outer surfaces. Thus, the present invention actually decreases the extent of the matrix necessary to effect refraction and reflection of the light within the sheet yet with at least a 50% increase in intensity thereby reducing time and labour and cost involved in producing the sign.
According to a preferred embodiment the region free of half tone array or arrays is located at or near the upper region of the first or second surfaces adjacent the illumination or light source. This has the effect of preventing refraction of light in the upper portion of the display so that by internal reflection increased illumination is achieved via the arrays which refract the light and facilitate an even distribution of light over the surface area of the display over the area of the half tone array.
According to the prior art dots are used and in the preferred embodiment of the invention disclosed in patent 647834 they were used on both sides of the acrylic sheet.
The unique matrix of half tone translucent arrays according to the present invention results in a 50% increase in light intensity for up to a 50% reduction in overall surface area of the matrix.
Further scope of applicability of the present invention will become apparent from the detailed description given hereinafter. However, it should be understood that the detailed description and specific examples, while indicating preferred embodiments of the invention, are given by way of illustration only, since various changes and modifications within the spirit and scope of the invention will become apparent to those skilled in the art from this detailed description.
REFERENCES:
patent: 5390436 (1995-02-01), Ashall
patent: 5433024 (1995-07-01), Lerner
patent: 5641219 (1997-06-01), Mizobe
patent: 5711589 (1998-01-01), Oe et al.
patent: 2064288 (1989-02-01), None
patent: 8622691 (1992-0
Birch & Stewart Kolasch & Birch, LLP
Eleven Lighting Pty. Limited
Tso Laura K.
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