United States Patent
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`Pristash et al.
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`[19]
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`Patent Number:
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`Date of Patent:
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`5,005,108
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`Apr. 2, 1991
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`Daniel .
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`Szeles .................................... 362/32
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`362/31
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`362/32
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`5/1985
`6/1987
`3/1988
`8/1988
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`1/1989
`4/1989
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`4,519,017
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`4,765,701
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`4,802,066
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`4,825,341
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`Awai I:................................... 362/32
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`Primary Examiner—Stephen F. Husar
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`Assistant Examiner—Sue Hagarman
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`Attorney, Agent, or Firm—Renner, Otto, Boisselle &
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`Sklar
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`[57]
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`ABSTRACT
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`Thin panel illuminator includes a solid transparent panel
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`member having one or more deformed output regions
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`which cause light entering the panel along an input edge
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`thereof to be emitted along the length of the panel.
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`Light may be transmitted to one or more panel input
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`edges from one or more light sources utilizing transition
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`devices which convert easily focused light generally to
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`the shape of the panel input surfaces.
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`76 Claims, 6 Drawing Sheets
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`THIN PANEL ILLUMINATOR
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`Inventors: David J. Pristash, Brecksville;
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`Jeffery R. Parker, Concord, both of
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`Ohio
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`Lumitex, Inc., Cleveland, Ohio
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`Assignee:
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`309,424
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`Appl. No.:
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`Filed:
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`Feb. 10, 1989
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`.................................. .. F21V 7/04
`Int. Cl.’ .......... ..
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`US. Cl. ............
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`.......................... .. 362/31; 362/32;
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`362/26
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`Field of Search ...................... .. 362/26, 27, 31, 32
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`References Cited
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`U.S. PATENT DOCUMENTS
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`2,480,178 8/I 949
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`Zinberg ............................ 350/96.10
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`3,043,947 7/ 1962
`Albinger, Jr.
`.... .. 362/32
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`.... .. 362/32
`3/1973
`3,721,815
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`3,760,179
`9/1973
`Addington, Jr.
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`3,781,537 12/1973
`Ramsey ..... ..
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`4,128,332 12/1978
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`3/1981
`4,257,084
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`4,323,951 4/ 1982
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`4,373,282 2/1983
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`154]
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`[751
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`Page 1 of 14
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`TOYOTA EXHIBIT 1007
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`U.S. Patent
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`LD.A
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`IWI2’
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`Sheet 1 of 6
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`Page 2 of 14
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`U.S. Patent
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`Apr. 2, 1991
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` Sheet 2 of 6
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`5,005,108
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`U.S. Patent
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`Apr. 2, 1991
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`Sheet 3 of 5
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`5,005,108
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`|||||||l|||fll||l|||||||||||l|\||||||
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`Apr. 2, 1991
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`5,005,108
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`Apr. 2, 1991
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`Sheet 5 of 5
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`5,005,108
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`FIG. I6
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`5,005,103
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`1
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`Tl-IIN PANEL ILLUMINATOR
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`5,005,108
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`In another form of the invention, the transition device
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`vided with single or multiple input and output ends of a
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`desired shape. Also, the input and/or output ends of the
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`transition device may be lens shaped to spread the light
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`evenly across such surfaces, and such surfaces may be
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`tion. Moreover, more than one transition device may be
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`used to transmit light from more than one light source
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`to a single panel, and the panel may have one or more
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`light output regions of various shapes to produce a
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`desired light output distribution.
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`To the -accomplishment of the foregoing and related
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`ends. the invention, then, comprises the features herein-
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`after fully described and particularly pointed out in the
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`claims, the following description and the annexed draw-
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`ings setting forth in detail certain illustrative embodi-
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`of but several of the various ways in which the princi-
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`ples of the invention may be employed.
`BRIEF DESCRIPTION OF THE DRAWINGS
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`In the annexed drawings:
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`FIG. I is a schematic perspective view of one form of
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`thin panel illuminator in accordance with this invention;
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`FIG. 2 is a schematic fragmentary perspective view
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`of a solid transparent light emitting ribbon panel
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`accordance with this invention;
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`FIG. 3 is an enlarged fragmentary side elevation view
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`of the ribbon panel of FIG. 2 schematically showing
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`how light rays are transmitted through and emitted
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`from such panel;
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`FIGS. 4-6 are perspective views of various other
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`solid transparent light emitting panels in accordance
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`FIG. 7 is a side elevation view of another fortn of
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`solid transparent
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`with this invention schematically showing light rays
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`entering opposite ends of the panel and being emitted
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`therefrom;
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`FIG. 8 is a schematic side elevation view of another
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`form of thin panel illuminator in accordance with this
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`invention;
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`FIG. 9 is a top plan view of the thin panel illuminator
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`of FIG. 8;
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`FIG. 10 is a top plan view of still another form of thin
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`panel illuminator in accordance with this invention;
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`FIGS. 11-14 are schematic longitudinal sections of
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`several forms of solid transparent light emitting panels
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`in accordance with this invention;
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`FIG. 15 is a top plan view of one form of transition
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`device in accordance with this invention for converting
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`an easily focused cross-sectional shape of light to the
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`shape of a panel input surface;
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`FIGS. 16-19 are schematic perspective views of vari-
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`this invention; and
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`FIGS. 20-22 are schematic perspective views of sev-
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`eral different shapes of panels constructed in accor-
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`dance with this invention.
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`DETAILED DESCRIPTION OF THE
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`PREFERRED EMBODIMENTS
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`Referring now in detail to the drawings, and initially
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`to FIG. 1, there is schematically shown one form of thin
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`panel
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`including a solid transparent light emitting panel 2 and
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`a light source 3 which generates and focuses light, in a
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`5
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`BACKGROUND OF THE INVENTION
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`This invention relates generally, as indicated, to a
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`thin panel
`illuminator including a solid transparent
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`panel member for conducting light and extractor means
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`for causing light conducted by the panel member to be
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`emitted along the length thereof.
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`Light panel illuminators are generally known. How-
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`ever, the present invention relates to several different
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`panel illuminator configurations which are less expen-
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`sive to make and/or provide for better control over the
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`light output from the panel. Also, the present invention
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`provides for more efficient transmission of light from a
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`light source to the light emitting panel.
`SUMMARY OF THE INVENTION
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`In one form of the invention disclosed herein, the
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`panel illuminator includes a light emitting panel mem-
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`ber made of a thin light conducting ribbon or film bent,
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`cast or formed into a predetermined pattern to cause
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`light conducted thereby to be emitted along the length
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`thereof. The effective radius of the bends, the number of 25
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`bends per unit length, the panel thickness, the index of
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`refraction ratio, and the internal ray distribution may be
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`controlled to control the panel light output and effi-
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`ciency.
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`In another fortn of the invention, the panel member
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`comprises a solid transparent wave guide having a pris-
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`matic surface on one side to cause the light rays entering
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`the wave guide through an input surface (end edge) to
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`exceed the internal critical angle and be emitted. The
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`size, shape and depth of the surface deformities may be
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`varied along the length of the panel to produce a de-
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`sired light output distribution. Also, a back reflector
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`may be used to redirect emitted light back through the
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`panel. Moreover, a second prismatic film may be placed
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`in closely spaced relation to the panel prismatic surface
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`to redirect the emitted light rays toward a particular
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`application.
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`In still another form of the invention, the panel mem-
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`ber comprises a prismatic film having prism ridges run-
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`ning generally parallel to each other, with deformities
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`along the tops of the prism ridges to cause light to be
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`emitted. Also, diffuser surfaces, which may vary in
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`depth and/or width, may be formed along the length of
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`the prismatic surfaces.
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`S0
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`In each instance, the panels may be shaped to fit a
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`particular application. Also, different light sources may
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`be used to supply the panels with different types of
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`radiation and reduce or eliminate others.
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`Further in accordance with the invention, the panel
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`input surfaces may be lens shaped or tapered to alter the
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`input light ray distribution. Also, such panel input sur-
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`faces may be coated with an antireflective or other
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`coating.
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`In accordance with another aspect of the invention, a
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`transition device is provided for converting easily fo- 60
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`cused light received from a light source to the shape of
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`the panel input surface. In one form of the invention, the
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`transition device includes an optical fiber transition
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`member having a round or other shaped connector at
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`one end to permit a source of light to be easily focused 65
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`thereon, and a rectangular or other shaped connector at
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`the other end corresponding in shape to the panel input
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`surface.
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`Page 8 of 14
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`3
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`predetermined pattern, either directly on a panel input
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`edge 4 or on a transition device 5 which is used to make
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`the transition from the light source 3 target shape to the
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`light emitting panel input edge 4 shape as shown. The
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`light that is transmitted from the light source 3 to the
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`light emitting panel 2 may be emitted along the length
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`of the panel as desired to produce a desired light output
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`distribution to fit a particular application.
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`A light source 3 of any suitable type may be used,
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`including, for example, any of the types disclosed in
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`copending application Ser. No. 125,323, filed Nov. 24,
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`1987, now U.S. Pat. No. 4,897,771, granted Jan. 30,
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`1990, and assigned to the same assignee as the present
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`application, which is incorporated herein by reference.
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`Light source 3 includes a radiation source 8 such as an
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`arc lamp, an incandescent bulb, a lens end bulb, an LED
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`or a fluorescent tube or the like, and may have a collec-
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`tor 9 which collects the light emitted by the radiation
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`source 8 and uniformly focuses the light on the input
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`end 10 of the transition device 5 with predetermined ray
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`angles to fit a particular application. For the thin panel
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`illuminator 1 of the present invention to operate effi-
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`ciently, the light source 3, transition device 5 and light
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`emitting panel 2 must be designed to fit each other as
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`well as the particular application. However, it should be
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`understood that the light source 3, transition device 5
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`and light emitting panel 2 may also be used separately if
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`Light emitting panel 2 comprises a solid transparent
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`or translucent wave guide 15 made of glass, plastic or
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`other suitable transparent or translucent material, with
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`disruptions 16 on at least one side 17 formed as by cut-
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`ting, molding, coating, forming or otherwise causing
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`mechanical, chemical or other deformations in the exte-
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`rior surface l8 thereof. When these disruptions 16 are
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`struck by the light rays entering the panel input edge 4,
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`they cause some of the light rays to exceed the internal
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`critical angle and be emitted from the panel. The
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`amount of light emitted from the panel will depend on
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`the type, shape, depth and frequency of the disruptions
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`16. For example, if the exterior surface 18 is mechani-
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`cally deformed at decreasingly spaced intervals as the
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`distance from the light source 3 increases, there will be
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`more uniform emission of light from the surface 18
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`when viewed from a distance. Also, such disruptions 16
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`may vary in depth and shape along the length of the
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`panel 2 to produce a desired light output distribution.
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`A back reflector 20 may be provided on the side 21 of
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`the panel 2 opposite the side 17 with the disruptions 16 50
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`therein. In like manner, an end reflector 22 may be
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`provided on the end edge 23 opposite the input edge 4
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`to minimize the amount of light escaping from these
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`surfaces.
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`Another light emitting panel 24 in accordance with
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`this invention is schematically shown in FIG. 2 and
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`comprises a thin light conducting ribbon or film 25 bent
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`into a wave form of predetermined pattern. Although
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`the dimensions of the panel 24 may vary, as an example,
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`the panel 24 may be approximately 0.020 inch thick and
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`have an overall height of approximately 0.040 inch, and
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`be of any desired width or length depending on the
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`particular application. Such a panel 24 may be made in
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`any suitable manner, for example, by vacuum forming
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`or injection molding. During the forming operation, the
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`ribbon or film 25 is bent in a predetermined pattern,
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`with the number of bends 26 per unit length, the effec-
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`tive bend radius, the panel thickness, the index of refrac-
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`45
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`4
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`tion ratio, and the internal ray distribution determining
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`the light output and efficiency of the panel.
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`When the wave guide 25 is bent, certain light rays
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`that were previously internally reflected will be emitted
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`if the bends are below a critical radius. The critical
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`radius is the radius of curvature at which these light
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`rays first start to be emitted. By making the bends 26
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`more or less pronouced, the percentage of light emitted
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`can be controlled for a given input ray distribution.
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`As schematically shown in FIG. 3, as certain light
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`rays strike a bend surface 26 of panel 24, they exceed the
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`internal critical angle and are emitted. If desired, one
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`side of panel 24 may be provided with a back reflector
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`27 that reflects the light emitted from that side back
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`through the panel towards an application as schemati-
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`cally shown in phantom lines in FIG. 3. Moreover,
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`selected light emitting areas 28 of the panel 24 may be
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`coated with a transparent coating 29 having a different
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`refractive index than the light conducting ribbon or film
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`25 to cause changes in the attenuation of light being
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`emitted from the panel 24 as further schematically
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`shown in phantom lines in FIG. 3.
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`FIG. 4 shows another form of light emitting panel 30
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`in accordance with this invention including a solid
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`transparent wave guide 31 similar to the wave guide 15
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`of FIG. 1 but having a prismatic surface 32 on a side 33
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`which is covered by a back reflector 34. Accordingly,
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`when the prismatic surface 32 is struck by light rays
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`entering an input end edge 35 of the wave guide 31,
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`causing the light rays to exceed the internal critical
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`angle and be emitted,
`the emitted light rays will be
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`reflected back through the panel by the back reflector
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`34 and out the other side 36 of the panel as schemati-
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`cally shown in FIG. 4. The angles and/or depth of these
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`prismatic surfaces 32 may be varied along the length of
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`the panel 30 to produce uniform or other desired light
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`output from the other side 36 of the panel.
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`In FIG. 4, the light rays are shown entering the panel
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`30 through an end edge 35 generally perpendicular to
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`the prism edges 37. Also, an end reflector 38 is shown
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`on the end edge 39 of the panel opposite the input end
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`edge 35. However, if desired, light rays may be caused
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`in
`to enter the panel 30 from both end edges 35, 39,
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`which event the end reflector 38 would be eliminated.
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`FIG. 5 shows another form of light emitting panel 40
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`in accordance with this invention comprising a solid
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`transparent prismatic film 41 having deformities 42 cut,
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`molded or otherwise formed along the top of the prism
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`edges 43. Although the deformities 42 are shown as
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`being of a generally triangular shape, they may be of
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`any desired shape that causes light to be emitted, and
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`may vary in depth and shape along the length of the
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`prism edges 43 to produce a desired light output distri-
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`bution. In this embodiment, light rays are caused to
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`enter the panel 40 from one or both side edges 44, 45 in
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`a direction generally parallel to the prism edges 43.
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`Alternatively, diffuser surfaces 46 may be formed
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`along the top edges 47 of the prismatic surfaces 48‘of a
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`prismatic film light emitting panel 49 as schematically
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`shown in FIG. 6. These diffuser surfaces 46 may vary in
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`depth and/or width along the length of the panel 49,
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`and may comprise a roughened surface, a lenticular
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`surface, or a prismatic surface or the like that consists of
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`multiple surface deformities. A roughened surface, for
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`example, may be produced by grinding, sanding, laser
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`cutting or milling. Also, both of the light emitting pan-
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`els 40 and 49 shown in FIGS. 5 and 6 may have pris-
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`matic surfaces on both the top and bottom surfaces
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`5,005,108
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`30
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`Page 9 of 14
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`6
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`mitting light from multiple light sources 82, 83 to differ-
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`ent panel input edges 84, 85. In the FIG. 10 embodi-
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`ment, two such transition devices 80, 81 are shown
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`connected to two panel input edges 84, 85 which are
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`substantially perpendicular to each other. The sides and
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`back of the panel 76 may have reflective coatings 86
`thereon.
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`Each output region 77-79 contains deformities 87
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`produced, for example, by molding, machining, stamp-
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`ing, etching, abrading, or laser cutting or the like to
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`cause light to be emitted therefrom. The light output
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`pattern or uniformity of light output from these output
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`regions 77-79 may be controlled by varying the shape,
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`depth and frequency of the deformities 87 relative to the
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`input light ray distribution. For example, the various
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`light output regions 77-79 of the panel 76 may be
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`etched, roughened or cut into different shapes and lev-
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`els of deformities using a laser by varying the power,
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`position and cutting speed of the laser.
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`FIGS. 11-14 schematically illustrate solid transparent
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`light emitting panels having differently shaped light
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`output regions. FIG. 11 shows a panel 90 with light
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`input at one end edge 91 only and typical light ray
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`travel. In this embodiment, panel 90 has a back reflector
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`92 on the bottom surface 93, an end reflector 94 on the
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`end edge 95 opposite the input end edge 91, and a de-
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`formed light output region 96 whose depth progres-
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`sively decreases along the length of the panel from the
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`input end edge 91 toward the opposite end edge 95.
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`FIG. 12 shows a panel 100 with light input at oppo-
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`site end edges 101 and 102 and a deformed output re-
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`gion 103 that progressively decreases in depth from
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`both input end edges 101, 102 toward the middle of the
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`length of the panel. FIG. 13 shows a panel 104 with
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`light input at one end edge 105 only and a deformed
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`light output region 106 on the bottom surface 107
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`whose depth progressively decreases from the input end
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`edge 105 toward the opposite end edge 108. Also, a
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`back reflector 109 is shown mounted on the bottom
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`surface 107 of the panel 108 to redirect the light that is
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`emitted from the light output region 106 back through
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`the panel and out the top surface 110. In this embodi-
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`ment, either an air gap or a transparent fill material 111
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`having a suitable index of refraction may separate the
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`back reflector 109 from the panel 104.
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`Panel 115 shown in FIG. 14 is similar to panel 104 of
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`FIG. 13 except that the back reflector 116 of FIG. 14 is
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`deposited directly on the deformed light output region
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`117 and the depth of the panel is substantially uniform
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`throughout its length.
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`In each instance, the light input surfaces (end or side
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`edges) of the light emitting panels may be lens shaped or
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`tapered to alter the input light ray distribution. Also,
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`such light input surfaces may be coated with an anti-
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`reflective coating or a coating that changes the numeri-
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`cal aperture of the panel. The numerical aperture is the
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`sine of the vertex angle of the largest cone of input rays
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`that can enter an optical system or element multipled by
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`the refractive index of the medium in which the vertex
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`of the cone is located. Moreover, the light input sur-
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`faces, bottom surface and/or top surface of the panels
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`may be coated to reflect or absorb certain frequencies of
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`light.
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`From the foregoing it will be apparent that the wave
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`guide confines and directs light in a direction deter-
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`mined by its boundaries, whereas the extractor causes
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`light to be emitted from the wave guide. Examples of
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`wave guides that may