US 3922073 A
A light diffuser system suspended from a ceiling below a light source includes a framework of T-bar members depending from the ceiling and defining rectangular openings. Secured in each opening is a one-piece, translucent plastic light diffuser panel, formed in a coffer configuration with the cavity opening downward and the walls of the coffer inclined slightly from vertical toward the center of the opening. The walls are tapered from the bottom to the transverse portion, and are painted with an opaque color coating on the ceiling-facing surface. Light diffusing through the translucent, transverse portion stikes the walls, illuminating the color coating more strongly as the taper of the walls increases, and causing a color gradient effect which enhances the apparent depth of the coffer and increases the esthetic appeal of the diffuser system.
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Description (OCR text may contain errors)
United States Patent 1191 Schwartz [4 1 Nov. 25, 1975 [5 LIGHT DIFFUSER SYSTEM Primary ExaminerRonald .1. Stem  Inventor: Robert A. D. Schwartz, 513 Amman! E'mmmer conmd l Independent Road. Oakland, Calif; Attorney, Agent. or Firm-Harris Zimmerman 221 Filed: Apr. 25, 1973  ABSTRACT  Apl. No: 354,348 A light diffuser system suspended from a ceiling below a light source 1ncludes a framework of T-bar members 1 depending from the ceiling and defining rectangular  US. Cl 350/319; 240/106 R; 350/259 openings. Secured in each opening is a one-piece,  Int. Cl. G02B 5/00; F21V 5/00 translucent plastic light diffuser panel, formed in a  Field of Search 350/319, 259, 168; coffer configuration with the cavity opening down- 0/l86 108 5 10 ward and the walls of the coffer inclined slightly from A vertical toward the center of the opening. The walls  References Cited are tapered from the bottom to the transverse portion. UNITED STATES PATENTS and are painted with an opaque color coating on the 3.104.834 9/1963 Lipscomb 350/319 ceillng'facing Surface- Light diffusing 509,668 5/I97O Omnger et aL 240/51. R translucent, transverse portion stlkes the walls, 111um1- 3,760,178 9/1973 Miller 240/106 R Hating the Color coating more Strongly as h taper 0f D173,157 10/1954 .the walls increases, and causing a color gradient effect D2l2.442 10/1968 Keller, Jr. D48/16 which enhances the apparent depth of the coffer and increases the esthetic appeal of the diffuser system.
13 Claims, 5 Drawing Figures U.S. Patent Nov. 25, 1975 FIG 3.
LIGHT DIFFUSER SYSTEM BACKGROUND OF THE INVENTION Light diffusing systems suspended from a ceiling have been used to distribute illumination from ceiling mounted fluorescent or similar lamps. Often these systems have employed translucent planar panels to form a continuous, flat diffusing surface extending over large portions of a ceiling. These monotonous expanses of illuminated panel have often contributed to an oppressive, non-productive room environment which is further exacerbated by the glare produced by such a system. The lamp fixtures and suspending structure have often cast shadows on the diffusing panels, which serve not to alleviate the monotony of the diffuser surface but to cause non-uniform illumination of the room, and confusing multiple shadows on work areas. Attempts to overcome these problems by introducing new systems which recess the diffusing panels or employ secondary diffusers have resulted in a proliferation of parts to be assembled during installation of each new system. The corresponding increase in man-hours required for complete assembly has resulted in higher costs without overcoming'all of the defects of the prior art.
SUMMARY OF THE INVENTION The present invention is directed toward a light diffusing system which overcomes the problems of the prior art and provides a textured ceiling which is a source of non-glaring illumination and is pleasing to the eye. It comprises a multiplicity of rectangular or square panels, each formed in a coffer configuration defined by a lateral translucent portion supported by upwardly extending walls which terminate at their lower extremities in horizontally extending flanges. A framework of T-bar members defining square openings which is suspended from the ceiling supports the panels with the flanges resting on the T-bars and the coffer cavities opening downward. The upwardly extending walls are tapered in thickness from the flange to the lateral portion, and are painted on their ceiling-facing side with an opaque color coating. Light from ceiling-mounted lamp fixtures diffuses through the lateral translucent portion of each panel, providing illumination to the area below and also illuminating the walls of the coffer. The taper of the walls causes them to reflect more lights from the upper portions than from the lower, so that the color reflected from the walls of each panel has ,an intensity gradient which enhances the depth effect of the coffer. The coffer configuration removes most of the lateral diffusing surfaces from direct view, greatly relieving the glare and brightness of the ceiling. Furthermore, the enhanced depth effect of the coffer panels and the color of the walls of the coffers provides a pleasant visual interest which is lacking in prior lightdiffuser systems. Because each panel is a molded single unit, installation is simple and economical, and maintenance of the lamp fixtures is easily facilitated. The panels may be used in luminous bays interspersed with acoustical tile or other suspended ceiling material, or they may be employed as a complete suspended ceiling.
THE DRAWING FIG. 1 is a perspective view of the present invention as seen from above.
FIG. 2 is a perspective view of the present invention as seen from below.
2 FIG. 3 is a sectioned side view of the present invention.
FIG. 4 is an exploded sectioned side view of a portion of a light diffusing panel.
FIG. 5 is a view similar to FIG. 4 illustrating a modified form of the invention.
DESCRIPTION OF THE PREFERRED EMBODIMENT area below. It should be noted that the framework may be formed with openings of various standard sizes with the panels dimensioned to' match, thus providing a selection of panel sizes to suit a wide variety of situations.
Each light diffusing panel is formed by molding translucent white acrylic plastic, plexiglass or the like into a single unit with a square coffer configuration, as shown in cross-section in FIG. 3. The panel 1 1 includes a horizontal flange 12 formed about the perimeter of the panel and resting on the horizontal portion 9 of the framework on all sides of the panel. Upwardly directed walls 13, which are inclined inwardly from vertical toward the center of the panel, support a laterally extending planar portion or top wall 14, and define a coffer cavity 20 therebetween which opens downward. Walls 13 are joined to the flanges 12 by a shoulder 15. All of the vertices are rounded to prevent stress concentrations.
Because each light diffusing panel is of unitary construction, it may be appreciated that installation is quick and economical. Each panel is lifted through its opening diagonally, turned and properly oriented, and set in place. No screws or bolts or other fasteners are required.
As shown in FIG. 4, each of the walls 13 is tapered in thickness from the base 16 to the top 17. The ceiling facing surface of the walls is painted or otherwise coated with an opaque pigmented coating 19. The coating blocks all light from the lamps above, so that the only illumination of the walls 13 comes from the light diffusing through the white, translucent portion 14. Because each wall is tapered in thickness, the incident light from 14 is reflected more strongly by the pigmented coating 19 at the top 17 of the wall, and is more dispersed and less intense at the thicker bottom 16 of the wall. Thus the color reflected from the wall has a gradient of decreasing intensity from the top to the bottom of the wall. This gradient serves to enhance the perceived depth of the cavity 20 and make the panels 11 more visually interesting and esthetically pleasing. The panels of the present invention may be arrayed in luminous bays interspersed with acoustical ceiling tile or the like, or may be extended over an entire ceiling, as shown in FIG. 2. It may be appreciated that due to the coffer configuration of the panels 11, the lateral, light-diffusing portions 14 are only partially visible at most from below, thus reducing glare and brightness while delivering optimum illumination. The luminous portions 14 set off in the coffer cavity by the colored 3 walls 13 and the dark frame of the framework 7 provide a striking and effective, yet economical light diffusing system.
It should be noted that the taper of the walls l3 may be inverted; i.e., thicker at the top portion 17 and thinner at the lower extremity 16, thereby inverting the intensity gradient and creating another striking yet pleasing visual effect. Also, it will be appreciated that instead of painting or otherwise laminating an opaque coating or layer on the outer surfaces of walls 13, the same general effect could be obtained by placing an opaque collar or sleeve over the walls.
A modified form of invention is disclosed in'FlG. in which the walls 13 are not provided with their outer opaque layer or coating. Instead, an acoustical ceiling is readily provided by coating or spraying a conventional acoustical material on the inner surface of walls 13 to form a layer 21. Such layer may be formed of any suitable open cell sound absorbing material, such as polyurethane foam, sprayed flocking and the like.
With this latter arrangement, light will only pass through the horizontal translucent wall portion 14, with the remainder of the coffer bearing the sound absorbing material.
As a further feature of the invention, it has been found that the color provided in the coating 19, described in the first described embodiment, has a substantial effect in providing novel harmonized lighting in a room. In other words, by selecting various colors for the coating, the color temperature of the room can be readily modified. For example, by providing a coating possessing an amber color, blue light will be absorbed.
It should also be understood that in order to optimize this color effect, the walls 13, which define an included obtuse angle with top wall 14, should be offset from the vertical by from about l0 to about 35, and preferably about 15 as shown in the drawing. This gives an included angle of about 105. Too great an angle will result in most light passing through the top wall and completely missing the side walls and entering the room directly.
1. Light diffusing means for a ceiling with a light source above comprising: a unitary member having side walls joined to a laterally extending top planar wall and defining a downwardly directed cavity, said top planar wall being translucent for the passage of light from the light source therethrough, and said side walls being translucent; and opaque means substantially completely covering at least one of the inside and outside surfacesvof all said side walls for preventing passage of light through said side walls and reflecting incident light passing through said top wall.
2. The light diffusing means of claim 1 in which said opaque means is affixed to the inner surface of said side walls and constitutes a sound absorbing material.
3. The light diffusing means of claim 1 in which said side walls and top wall define a coffer, and in which said side walls converge towards said top wall.
4. The light diffusing system of claim 1, in which the outer surfaces of said side walls are provided with said opaque means as a film to reflect incident light passing through said top wall.
5. The system of claim 4 in which said film comprises a pigmented paint applied to said surfaces.
6. The system of claim 1 in which said side walls are tapered in thickness from said top wall to the distal ends of said side walls.
7. The system of claim 6 in which said side walls have a minimum thickness adjacent said top wall.
8. The system of claim 1 wherein said member includes horizontally extending flanges extending outwardly from the distal end portions of said side walls.
9. The system of claim 1 wherein said opaque means is provided with a color.
10. The system of claim 4 wherein said opaque means is provided with a color.
11. The system of claim 1 wherein said side walls define included obtuse angles with said top wall.
12. The system of claim 11 in which said obtuse angles are in the range of about to 125 13. The system of claim 11 wherein said angles are about