US2519387A

US2519387A - Glake free lighting device

Info

Publication number: US2519387A
Authority: US
Publication date: 1950-08-22
Anticipated expiration: 1967-08-22

Description

s- 22, 1950 A. M. MARKS 2,519,387

GLARE FREE LIGHTING DEVICE Filed June 15, 1946 INVENTOR. fi; w/v M Mann's faxm planes.

Patented Aug. 22, 1950 UNITED STATES PATENT OFFICE GLARE FREE LIGHTING DEVICE Alvin M. Marks Flushing, 181.1. Application June 15, 1946, SerialNo. 676,916 7 Claims. (01. 88-65) This invention relates to devices for providing glare-free illumination.

An object of this invention is to provide a lighting device which gives glare-free illumination to both horizontal and vertical surfaces.

The novel features characteristic of this invention are set forth with particularity in the appended claims. The invention itself, however, both as to its organization and its method of operation, together with additional objects and advantages thereof, will best be understood from the following description of a specific embodiment when read in connection with the accompanying drawing, in which:

,Figure 1 shows a means for providing glarefree illumination in the form of selectively polarized light adapted to illuminate both horizontal and vertical surfaces from a single source.

Figure 2 shows a diagrammatic showing of a system of general room illumination adapted to provide low intensity light and glare-free illumination of vertical and horizontal surfaces simultaneously.

In Figure 1 I show a particular meansfor providing polarized illumination in all radial directions from a central source so as to provide simultaneous glare-free illumination for objects having both vertical and. horizontal surfaces. To eifect this result, it is necessary that light directed onto the vertical and horizontal surfaces be respectively polarized in different planes in its path from the source of illumination. By way of illustrating the vertical surfaces which are to be illuminated, I show a picture I55 and a ray I5I polarized in a vertical plane as indicat"d at I52 impinging upon that picture to provide a glare-free illumination. I also show ahorizontal surface such as a table or a floor I53 and a ceiling I56 and rays I55 and I56 respectively impinging on these respective surfaces, said ravs I55 and I56 being polarized in a plane which is normal to their plane of incidence as shown by the dots I5'II58 respectively.

To provide this dual glare-free illumination by means of properly positioned polarized media cooperating with directed beams of light, I have shown by way of illustration, a fixture in which I provide a light source I60 surrounded by a sheet polarizer containing aligned herapathite crystals or other suitable polarizers.

first pass through a circumferential polarizer. It comprises segmented radial portions I62 with the axis of polarization I63 lying in the indicated The. axis of polarization of these seg- The rays which impinge upon the horizontal surface I53 ments coincide with the tangent of the circle whose center is the common vertical axis passing through the light source. By means of these radial segments of polarized sheets, light passing downwardly from light source IE0 is plane polarized to provide the properly polarized light beam I55 as described above. I I;

In lace of the segmented circular sheet a sheet which has the crystals thereof aligned in concentric circles may be employed. Such a sheet may be made, for example, by the method disclosed in the patent to Zocher, No. 1,873,951 by applying a dichroic dye to the surface of a transparent support and rubbing the surface in a rotating direction. Such a polarizer may also be produced by polishing a sheet of polyvinyl alcohol containing a dichroic dye in a circular direction or by other ways known in the art.

Another means of polarizing rays which are directed upon horizontal surfaces is shown as a frustum of a cone I65 which may be a completed cone as shown by the dotted lines I65 or may terminate in a cut-off section I61 as shown in dotted lines. The cut-off section I61 may comprise an absorbing surface or an internal refleeting surface of suitable characteristic or may be left open for the passage of non-polarized illumination as here shown. The frustum of the cone I65 may be constructed of any suitable polarizer such as a plastic sheet polarizer containing properly aligned crystals. The axis of polarization of the frustum of the cone is shown by dotted line I68 and said axis of polarization follows the circumference of concentric circles having a center in the common vertical axis of the cone. Light then passing from the light source through this cone comprising the polarized sheet is properly polarized as shown'at I58 for the light beam I 56. It is understood that the frustum of the cone or the completed cone shown may also be applied in lieu of the circumferential polarizer I62 to the lower horizontal surface. In other words, I provide the cone or cone frustum shape having a polarizing axis as indicated, as an'important, independent aspect of my invention to provide proper polarization'for light to be directed upon horizontal surfaces. Y Forlight which is to be simultaneously directe onto vertical surfaces such as picture I 50. I provide a cylinder which may comprise a sheet polarizer or segmented flat strips. It is important that the axes of polarization be'as indicated by the dotted lines IT!) for illuminating vertical-surfaces. In this case, the axes of polarization of the polarizing cylinder is such that theseaxes are all parallel to the common vertical axis. The effect of this construction is to polarize horizontallydirected rays I5I in a vertical plane as shown at I52 and furthermore provide glare-free illumination for such vertical surfaces. These horizontally directed rays are such that they are substantially parallel to horizontal surfaces I53I54 and so cannot be reflected from these horizontal surfaces to cause a glare. It is understood that rays I5I arealso directed upon vertical surfaces at approximately 33 so as to provide the proper angle of incidence for best glare-free illumination.

To effect this proper angular direction, 'it' is best to provide block-outs or louvres and prevent a direct 90 angular impingement of the'polarized light onto the vertical surface. .Areas which are not illuminated because of these block-outs can be properly illuminated with glare-freepolarized lamps suitably spaced apart which are positioned to direct, at -the 'proper angle, *pola'r'ized light'therefrom. The figure is diagrammaticand is reduced-toessentials,' but "it is understoodthat "the principles embodied therein can be improved'or enhanced-by additions of suitable reflectors, "diif'u'sin'g' mediums and all other-well known devices common-in the art.

In FigureZI'showa sys'temiorpro'viding glarefree low intensity light for a room and its 'contents which, of-course, compriseboth horizontal and vertical sur f aces. 'To do this ,"I provide simultaneously horizontally directed light rays containing vertically plane polarized light and light directed-upon horizontal surfaces containinglight polarized 'ina'plane normal toits plane: of inci- 'dence, both such families of rays being simultaneously-projected. 'To carryout this system of illumination, "I provide a light souroe I15 whichsimultaneouslyprojects light rays I18, I11 and I18 throug-h polarizers I 14 and I88. Polarizer l li' has an axis of polarization adapted topolarize lightbeam 16 so as to provide light vibrating in a plane normal to"the"plane of final incidence of light as show-net I8I. Thisso-polarized light is directed :onto' a suitable reflecting surface I82.

'Surface 182 has a suitable reflecting surface su'clr'asa ameta llic reflecting surface. For example; "F82 might be a wall of 'suitablecurvature ":covered with aluminum :particles in a transparent vehicle or the wall mightcomprise ametallic *foil paper whichsmight contain embossed designs for the purpose of ornamentation. Inthe event that thegeneralplan'epf the wall is desiredto'be substantially vertical, it'isx'contemplated that the wall :paper be suitably=embossed orimolded with directional metallic'i-planes to cooperate-with the *a'forementionedilight 's0ll1Ce s0 :as 'to direct "a polarized beam zupon? horizontal surfaces at the angles indicated'intthis' figure. 'Spec'rficallyI'mean :by this that I'may'provideangular directing're- .Tfle'cting surfaces comprisinga'multiplicity of suitaablyxoriented facets obtaind by rmoldingxor em- 'bossing which, although collectively positioned'in :-'a substantially vertical :p1ane,'efiectively act 'to direct light therefrom in theangularrange which would :normally'be obtained by a plane surface having the curvature indicatediat i815.

Referring now to the path of the light ray I18 "after reflection from the reflecting surface I82,

this polarized light is directed downwardly upon horizontal surfaces at the best angle to provide glare-free illumination. This range is, for example; from 20 to 70 with a preferred angleof approximately 33. Now referring to the rays -i-I'it'ended forthe illumination of vertical surfaces,

and

I88 and I89 are all traveling in horizontal directions; any appearance to the contrary being due to'the perspective of the drawing. By horizontal directions is.meant that the rays travel in a substantially'horizontal direction, but of course there wilkbesomerdeviation therefrom due to scattering and diffusing effect on the reflecting surface I83. A bottle- I90 is shown as illustrative of an object having vertical surfaces.

It is to'- be "pointed-"out further that vertical rays I81, I88 and I89 are preferably constrained 'byproperlydirecting the reflecting surfaces or'by blocking members so that said rays impinge upon said vertical surfaces at substantially the proper 'angle therewith.

.By the provision ofa wall surface which 'imparts the indicatedangular-direction of therespective rays=and which comprises a'reflector that reflects po'lar'izedlight, I provide not only for the aforementioned glare free illumination of both vertical and horizontalsurfaces, butI also provide "a low intensity soft illumination within the room.

"Particularlylhave provided a new 'system of illumination which comprises the directing simultaneously of a multiplicity "of "light rays, polarizing these in suitable planes for the ultimate purpose of providing .glare free illumination'for'the particular surfaceswhich thelight rays are to illuminate and 'for further carrying out this scheme I have provided' metallized or other suitable nondepolarizing reflecting surfaces of large area 'whichgfor example, may be the walls or ceiling :of the room :andas'a further'modification' of this 'system I provide an-ornamentation of these surfaces, such ornamentation being such as to'fully absorb the light in certain'areas or to reflectiit without depolarization.

It is to 'be 'noted'that'the polarizing means I14 I88 comprise two polarizers having their axes of polarization at right angles and that these polarizers are respectivelr, positioned soias to intercept and properly polarize light which after reflection from the cooperating reflecting surface is directed substantially onto particular planes.

partingfrom the .broad scope of this invention.

This alpplicationlis 'a continuation-impart of .applicatiomSerial -No; 240,608,.filed November 16, .1938 (now Patent 2,402,176,.June18, -1946)"which in turnis a: continuation-in -part of application :No."755;55'1,*filedTDecember'l, 1934,"now abandoned.

Although certain "specific embodiments of this invention have been ShOWIl and describe'dfit will be understood that-many modifications thereof are possible. This invention, therefore, is not to be restricted except insofar asis necessitated by the prior art and by the spirit of the appended claims.

I claim:

1. In a nonglare lighting device, of the type in which the lighting device is supported from a substantially fiat surface which is to be illuminated, the novel combination which comprises a supporting member extending in a perpendicular direction with respect to said flat surface, a light source held by said supporting member and positioned on an axis normal to said flat surface and adapted to cast light in divergent directions, a polarizing disc also held by said supporting memher and being parallel to said flat surface and centered on said normal axis, the polarizing disc comprising a plurality of segments, the polarizing axis of which are substantially normal to the radii from the center of said disc, whereby nongl-aire polarized illumination is obtained in a plurality of directions simultaneously,

2. The device of claim 1 in which the polarizing disc is composed of segments so combined that the planes of polarization of light transmitted through the disc is tangential with respect to circles centered on said normal axis, in planes parallel to the illuminated surface whereby radially directed nonglare polarized illumination is obtained in a plurality of directions simultaneously.

3. The device of claim 1 in which the segments of said polarizing disc are so numerous as to produce essentially circular lines of polarization.

4. In a nonglare lighting device of the type in which the lighting device is supported from a substantially horizontal flat surface which is to be illuminated, the novel combination which comprises, a light source positioned on a vertical axis adapted to cast light in substantially all directions, and in proximity thereto a compound polarizing screen comprising a segmented disc, each of said segments having a polarizing axis substantially perpendicular to the line bisecting the angle of the segment of the disc to polarize light tangentially with respect to circles in horizontal planes .and centered on said vertical axis,

said lighting device being placed so that the said disc is located between the light source and the said flat surface which is to be illuminated, said compound polarizing screen also comprising a portion surrounding the light source extending from the periphery of said disc, said surrounding portion having its plane of polarization in a vertical direction being adapted to polarize horizontally directed light from said light source in a. vertical plane, whereby radially directed nonglare polarized illumination for both horizontal and vertical surfaces is obtained in a plurality of directions simultaneously.

5. In a nonglare lighting device of the type in which the lighting device is supported from a substantially horizontal flat surface which is to be illuminated, the novel combination which comprises, a light source positioned on a vertical axis adapted to cast light in substantially all directions, and in proximity thereto a compound polarizing screen comprising a segmented polarizing disc each of said segments having a polarizing axis substantially perpendicular to the line bisecting the angle of the segment of the disc to polarize light from said light source tangentially with respect to circles centered on said vertical axis and in horizontal planes, said disc being located between the light source and the said flat surface which is to be illuminated, said compound polarizing screen also comprising a portion surrounding the light source extending from the periphery of said disc, said surrounding portion having its plane of polarization in a vertical direction being adapted to polarize horizontally directed light in a vertical plane, said compound polarizing screen further comprising a frustoconical portion the larger end of which is united to the end of said surrounding portion opposite to the disc, said frustoconical portion having polarizing elements oriented so that the transmitted light is plane polarized tangential to circles constructed on the frustoconical surface whereby radially directed nonglare polarized illumination is obtained in a plurality of directions, for horizontal and vertical surfaces, simultaneously.

6. In a nonglare lighting device, a light source adapted to cast light in substantially all directions in combination with a compound polarizing screen, said screen comprising a cylindrical portion surrounding the light source and having polarizing axes adapted so as to polarize horizontally directed light in a vertical plane and a frustoconical portion closing one end of the cylindrical portion, said light source being located on the axis of said frusto-conical portion and said frustoconical portion being composed of a polairizing element so constructed that transmitted light is plane polarized tangential to circles constructed on the frustoconical surface.

7. In a nonglare lighting device, a source of light, an enclosure made of polarizing material surrounding said light source said polarizing enclosure comprising a dichroic polarizing member in the form of a frustoconical section, the polarizing axes extending substantially along circles, the planes of which circles are normal to the axis of the frustoconical section, said source of light being located in the axis and adjacent the larger end of said frustoconical section so that every ray passing through said frustoconical section will be polarized in a, plane normal to the plane of incidence of the ray on the surface viewed whereby radially nonglare illumination is obtained in a plurality of directions simultaneously.

ALVIN M. MARKS.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 1,610,423 Ca wley Dec. 4, 1926 1,733,915 Short Oct. 29, 1929 1,873,951 Zocher Aug. 30, 1932 2,096,696 Land Oct. 19, 1937 2,122,225 Wheelwright June 28, 1938 2,252,324 Land Aug. 12, 1941 FOREIGN PATENTS Number Country Date 803,464 France July 6, 1936 48,249 France Aug. 10, 1937 (1st addition to No. 803,464) 603,326 Germany Sept. 27, 1934 460,666 Great Britain Jan. 28, 1937