US2882631A

US2882631A - Display materials, devices and systems

Info

Publication number: US2882631A
Application number: US308096A
Authority: US
Inventors: Boone Philip
Original assignee: Individual
Current assignee: Individual
Priority date: 1952-09-05
Filing date: 1952-09-05
Publication date: 1959-04-21
Anticipated expiration: 1976-04-21

Description

APfl 2l, 1959 P. BOONE DISPLAY MATERIALS, DEVICES AND SYSTEMS Filed Sept. 5. 1952 xlHll IN VEN TOR.

United States Patent O DISPLAY MATERIALS, DEVICES AND SYSTEMS Philip Boone, Winchester, Mass.

Application September 5, 1952, Serial No. 308,096

21 Claims. (Cl. 40-130) This invention relates to improvements in decorative and display materials, devices and methods, and more particularly to such improved materials, devices and methods utilizing polarized light.

The present invention relates to decorative and display materials, devices and systems which provide visible areas of original and striking appearance through relatively simple constructions and at reasonable cost. They involve the projection, modification and reflection of polarized light and are adapted, for example, to window display, interior display, outdoor advertising, decorative and theatrical setting uses. A principal characteristic of the present materials, devices and systems is their adaptability for combination with presently used or readily accessible materials and methods in the art to obtain novel results. This permits improved visual effects relative to existing materials and methods but avoids the excessive cost which would be involved in completely discarding present techniques.

Accordingly, an object of the invention is to provide light polarizing materials, products, devices, methods and systems which provide novel and attractive visual results for decorative, advertising and display purposes.

Another object of the invention is to provide improved materials and methods for achieving the first-named object.

A further object of the invention is to provide the aforesaid materials and devices in the form of simple and eilicient constructions and at reasonable cost.

A still further object of the invention is to provide novel materials, devices and methods in combination with present materials and methods used in the art to achieve improved display and decorative products.

Another object of the invention is to provide decorative and display products wherein surface glare is substantially eliminated and effective reflectivity, contrast and width of viewing angle are obtained.

These and other objects of the invention will be apparent from the following description taken in conjunction with the accompanying drawings wherein like reference characters refer to like parts throughout the several views.

Figure 1 is a front view of an advertising display unit or assembly of the invention;

Fig. 2 is a side View, in cross section, illustrating the` method of attaching composite light-polarizing material of the invention to a section or panel thereof;

Fig. 3 is a similar View of a modification of the method shown in Fig. 2;

Fig. 4 is a similar view of a further modification of the method illustrated in Fig. 2;

Fig. 5 is a similar view of a modified panel or area of the invention;

Fig. 6 is a side view in cross section which illustrates a composite reflecting-light-polarizing material of the invention;

Figs. 7 through l0 are side views in cross section which illustrate modifications of the composite material of Fig. 6.

"ice

Referring to Fig. l, a display area of the invention such as an advertising panel or pictorial unit is illustrated. This unit is capable of showing visible changes in certain portions when subjected to controlled polarized light, and may also show various changes in other portions when subjected to other types of light. The words always, keep cool," aero and cigarettes and the

portions

12, 14, 16, 18, 20 and the border 22, in a basic construction, are formed of a composite material comprising a lightpolarizing element, a nondepolarizing reflecting element and, preferably, at least a light-diffusing element. These light-polarizing-rellecting-diflusing portions will be referred to as polarizing-reflecting herein. Other sections of the border are to be assumed to have alternate polarizing directions similar to those above. These portions are subject to the above-named changes in polarized light. The double-headed arrows indicate polarizing directions or axes of the respective portions. The surrounding area of the unit 24 and the word smoke may be formed of paints, dyes, photographic prints, composite metallic material, fluorescent or phosphorescent materials et cetera, preferably substantially depolarizing, applied to the panel and depicting any desired message, scene or design. The composite polarizing-reflecting material, in certain instances, is attached either directly to the unit or panel or to

sections

26, 28 and 30 which, in turn, are superposed and fastened to the panel. These sections may be of wood, metal, plastic or any suitable material. Other portions of the polarizing material, such as the word aero and

portions

12, 14, 16, 18 and 20 may be bonded directly to the surface 24 of the unit. Border 22 may be attached to the unit or to a strip which, in turn, is bonded to the unit. Any suitable bonding substances or fastening means may be employed for attaching the composite polarizing-reflecting material or sections. Shading 32 and eye portion 34 represent opaque, translucent or transparent paint, dye, etc. applied to the surface of the composite polarizing material. The composite polarizing-reflecting material may suitably be bonded to the display unit, to section components of the unit as shown in Figs. 2, 3 and 4, or it may of itself form a section or panel wherein letters and figure areas etc. remain clear and are given shape by painting around them with opaque paint as shown in Fig. 5. In Fig. 2 the composite polarizing-material 36 is attached to a section or unit 38 by a bonding substance 40, the section having a cut-out portion 42 through which the polarizing material is visible. In Fig. 3 the composite polarizing-reflecting material 44 is inlaid in a cut-out p0rtion 46 of a section or unit 48. In Fig. 4 the composite polarizing-reflecting material 50 is bonded to the surface of a section or unit 51 by a bonding substance 52. In Fig. 5 the polarizing-reflecting material 53 has an opaque paint 54 applied to certain surface portions so as to form the contour and surrounding area of nonpainted functional portions. Operation of the unit of Fig. 1 will further be described relative to a coacting polarizing light source providing axially changing polarized light.

Figs. 6 through l0 illustrate various constructions of composite polarizing and rellecting material which may be used in the unit of Fig. l. In Fig. 6 the construction includes a diffusely-rellecting layer 56 and a light-polarizing layer 58, the reflecting layer being somewhat exaggerated. Fig. 7 shows a reflecting means 60, a lightpolarizing element 62 and a diffusing layer or means 64. Fig. 8 represents a reflecting means 66, a light-polarizing means 68 and a diffusing lens-like surface layer 70. In Fig. 9 the assembly includes a reflecting surface 72, a light-polarizing means 74, a birefringent layer 76 and a diffusing portion 78 which may be a separate layer or incorporated with the preceding layer. Fig. l0 illustrates a reflecting layer 8|), a birefringent layer 82, a polarizing layer 84 and and a diffusing means 86. In the foregoing constructions, the respective layers are preferably laminated or bonded together by any suitable means, using subcoats as necessary, or the reflecting and diffusing layer may be coatings applied to the polarizer. In turn, the polarizer could be a coating applied to either the reflecting or diffusing layer. Bonding materials, such as polyvinyl alcohol, vinyl resins, polyvinyl butyral, cellulose acetate et cetera, may be used, depending upon the layer materials employed. The reflecting layer may be located in its functional area and held in assembled relation by any other suitable fastening means in a modification. Or. the reflecting layer could be formed on the supporting unit and any of the constructions of Figs. 5, 6, 7, 8, 9, l0, minus a reflecting element, be bonded thereto.

The light-polarizing elements of the constructions of Figs. 1, 6 through l0, and of polarizing light source means, used therewith, may be formed of any suitable commercially available polarizing material. Such material is manufactured as a film by Polaroid Corporation, Cambridge, Massachusetts, and as a coating by Polacoat Corporation, Blue Ash (Greater Cincinnati), Ohio. The reflecting coating may, for example, consist of aluminum foil (preferably employing a matte surface thereof), a deposition in vacuum of aluminum, a metallic coating applied, for example, by a spray, brush or dip method, or a chemical deposition. Alternatively, the reflecting layer could be applied as a metallic powder (i.e., aluminum) to a surface of the polarizer which has been softened by a solvent or which has been treated with a transparent adhesive. If, for example, the polarizer has an acetate supporting layer it could be treated briefly with acetone and the aluminum powder applied thereto. The diffusing layer may, for example, be a "flat varnish or lacquer, a plastic layer applied by a dipping, laminating or spraying process, a sand blasted, rubbed or otherwise produced matte surface. The birefringent layer may be formed of stretched polyvinyl alcohol, cellulose acetate, ethyl acetate, regenerated cellulose or any suitable material. The rear surface of the reflecting means, as well as edges and frontal surface of the composite material, may be protected against weathering by a suitable varnish, lacquer or other transparent coating. Any of the components of the composite materials of Figs. 6 through l0 may embody a tint, a dye, a fluorescent or phosphorescent substance or the like so as to provide a color or a luminous characteristic especially when the display unit is subjected to a source such as daylight, nonpolarized artificial light, ultraviolet light, et cetera.

In the constructions of Figs. 6, 7 and 8, incident axially varying polarized light is blocked by the polarizing layer when vibrating at 90 to the vibration direction of the layer, thus producing extinction or a dark appearance of the composite material. If the polarizing light source includes a birefringent element in the path of axially varying polarized light, an interference phenomenon produces color changes in constructions of Figs. 6, 7 and 8. Further interference color changes are possible through the construction of Fig. 9. The assembly of Fig. l0 shows interference colors in normal light and further changes of interference color and reflectivity in changing polarized light.

Again referring to Fig. 1, assuming that its composite polarizing portions are generally similar to constructions of Figs. 6, 7 or 8 and that section 28 surrounding the words keep coo is of a dark quality, than axially changing polarized light from a projector will produce the following effects. The words always and cigarette and

portions

16, 18 and 22a will change from bright to dark, or vice versa. The words keep cool and portions 14 and 22h will equally change during a second 90 rotational cycle. The word aero and

portions

12, 20 and 22e will undergo an equal change during a third 90 rotational cycle. The second and third cycles commence within the first cycle. At its dark stage, keep cool will merge into the dark surrounding area of section 28 and disappear." At its dark stage, eye 14 will apparently close. The

smoke

18, 20 and border 22 will apparently be iii continuous movement. The word smoke is formed of a conventional paint, dye, fluorescent substance or the like. Because the polarizing light source constantA ly illuminates the entire unit, areas other than those above described constantly reflect incident light rays. Shaded areas of the word aero, the figure of the girl. the cigarette and the background may be formed of other materials such as described relative to the word "smoke. lf embodying fluorescent substances, for example, they may show special effects when subjected to ultraviolet light alternatively produced, for example, by an ulti'aviolet light source and timer. Also, certain portions of the unit may be outlined by neon tubes or comprise incandescent bulbs for alternate effects controlled by a timer. The unit of Fig. l is merely illustrative and ii will be apparent that through controlled orientation of polarizing-reflecting portions, which may also include a horizontal and other directions of orientation, use of dyes and pigments therewith et cetera, many other effects mayv be obtained involving change and animation. As ex amples these could include effects of changing baci;- grounds, moving fluids, clouds, snow, objects, word messages and the like. Furthermore, certain arcas of theunit may be treated independently of other areas by limit ing areas which are illuminated by individual light sources. One light source may be a polarizing source, such as described herein, while the second source provides unpolarized light. Or, for example, both sources may be polarizing, though providing simultaneously dit ferent directions of polarization. i

Assuming the use of a birefringent element with the source of varying polarized light, color changes will be visible in the unit of Fig. l. These changes will occur in the various portions as cycles substantially in the order described relative to changes from dark to bright, and similar colors will be visible in portions similarly oriented. The colors are determined by the birefringence of the doubly refractng element employed, namely, by the thickness, relative direction of a principal axis and degree of orientation of the element. A 90 rotation of the polarizing element of the light source will, for example, provide complementary colors in any given polarizingreflecting portion of the unit of Fig. l. Additional color effects are obtained if the polarizing-reflecting material contains a light-absorbing dye, tint or the like, as above described.

In a lightpolarizing display system such as exemplified by the present invention, it is of the utmost importance to prevent visible surface reflection of the light source and to substantially eliminate visible surface reflection of extraneous light by the light-polarizingreflecting material employed. It will be apparent that such surface reflections would prevent the material from appearing dark when the polarizing axes of the projector and material components are crossed at 90. Color effects produced by a birefringent projector element would also be seriously impaired. The type of reflection required is that wherein the incident rays pass through polarizing means. and, according to the construction, through diffusing and retarding means, to the reflecting means and return. The aforesaid undesirable surface reflections are substantially reduced by providing reflection-reducing, diffusing or matte surface means, examples of which are shown in Figs. 7 through 10. Any remaining surface reflections may be rendered substantially imperceptible by controlling the location and projection characteristics of polarizing light source means with respect to a display unit so that surface reflection of rays by the unit is caused to be invisible to the viewer. As an example, using a Projector Flood" lamp manufactured by General Electric Company, Schenectady, N.Y., in a polarizing projector having an optical axis tilted at 45 relative to the plane of a display unit and spaced at ve feet from the unit, no surface glare from polarizing-reflecting portions distributed throughout the unit were visible at distances exceeding live feet from the unit. It will be apparent that correct angles of rays may be determined for all viewing positions relative to polarizing display systems located at various heights, horizontal positions and distances and that projectors may be predeterminedly positioned for providing these angles. It will be further apparent that a slight tilting of the display unit may be employed for contributing to correct angles of the rays relative thereto.

A second important consideration in an efficient polarizing-reflecting display system is the reflection of polarized rays from the unit throughout a sufliciently wide angle for general viewing purposes. This may be achieved by providing within a polarizing-reflecting portion suitable reflecting and diffusing properties of its reflecting means, predetermined diffusing properties of its surface layer or element, diffusing and collimating means associated with the light source and by a predetermined projection angle (optical axis) of the polarizing light source (projector). Each of these constructions or controls may be utilized or they may be employed in the system as a carefully balanced combination of cooperating means. For example, a polarizing-reflecting material providing an extremely wide angle of reflected rays includes a reflecting means formed by spraying an aluminum paint, powder or lacquer on a surface of polarizing material comprising a film of treated polyvinyl alcohol bonded to cellulose acetate or cellulose acetate butyrate. A polarizing film backed by the matte surface of aluminum foil provides possibly a more brilliant reflectivity but a narrower angle of reflected rays. A chemical or vacuum deposition of metal (i.e., aluminum) on a preferably matte-formed surface of the polarizer, constitutes another suitable reflecting means.

A third important consideration in display devices and systems of the invention is the reflection of adequate light from polarizing-reflecting areas relative to the type of display unit and viewing distances contemplated. Thus, a unit providing changes in wording which are intended to be visible at a considerable distance may require greater brilliance in the polarizing-reflecting portions than is required of figure or design changes in window display or other interior use. For maximum brilliance throughout a relatively narrow angle, aluminum foil, deposition coatings and the like may, for example, be employed as a reflecting means, as above described. The intensity of the light source may also be increased. Because commercial types of polarizers often transmit preferentially within certain wavelength bands, light sources which provide illumination preferentially or substantially completely within those bands may advantageously be used. Thus, for example, where the polarizer transmits more favorably a yellow-green wavelength, a sodium type of light source may present advantages in producing reflected rays from the polarizing-reflecting areas of increased visibility. In other instances, a mercury vapor type of lamp may be employed. In general, however, conventional incandescent light means are satisfactory. It will be understood that the limitations of the relatively narrow angle, above-referred to, may be overcome by using a plurality of light source means, in which case functional reflected rays are visible from all required viewing angles. Thus, for example, a plurality of projectors may project a plurality of cones of light of given angular width and, through the reflecting, polarizing and diffusing properties of the constructions exemplified in Figs. 6 through 10, coacting therewith, a plurality of cones of reflected rays of light of narrower angular width may be produced. These reflected rays may be of marked brilliance and, through the aforesaid angular positioning of the projectors, bundles of the rays are visible from any required viewing position. Where, as above-described, less brilliance is required, the reflecting-polarizing material may have a reflecting element which provides adequate but less brilliant reflectivity throughout a wide angle. Such an element is provided by the metallic paints, powders, sprays or lacquers, above referred to, applied to the polarizer. A very satisfactory reecting means of this type is provided by Krylon Aluminum Acrylic Spray manufactured by Krylon, Inc., Philadelphia, Pa. It is to be understood that the diffusing layer or treatment shown in Figs. 7 through 10 and above described relative to elimination of surface reflections also widens the angle of visible rays from the polarizing-reflecting material and may be employed to advantage with the various types of reflecting means of the invention. The diffusing layer also modifies the polarization of polarized rays from the projector and thus modifies the contrast and quality of colors provided in the polarizing-reflecting areas. Thus the degree of diffusion provided depends upon the exigencies of reduction of Surface glare, increase in visual angle and modification of polarization of incident rays required in a given system to produce a given result. To be balanced with the aforesaid diffusing means of various degree are the various reflecting means, types of light sources and relative positioning of light means and display units previously described.

From a commercial aspect, it is to be understood that materials described herein and exemplified in Figs. 5 through l0, may be supplied with or without reflecting elements, that adhesive means may be formed on the back or specially supplied therewith, that opaque or translucent designs or configurations may be formed on the front surface and that polarizing elements may have a plurallty of orientations. The latter may be achieved by a single layer having several orientations or a plurality of sections carried by a support. Where birefringent elements are employed they may similarly have several retardation values. The materials may be marketed in panel or roll form or in special shapes.

Polarizing elements of the display unit may be composed, entirely, or partially in conjunction with the plane polarizing elements hereinbefore described, of circularly polarizing materials, i.e., of right-handed and left-handed polarizing film materials, in which instance they would be used with light sources having variable rightand left-handed light-polarizing filters. The use of circular polarizers as supplementary means would provide changes, such as those of animation and color, additional to the changes visible in the plane polarizing areas of the display.

Where half-tone effects are desired, translucent paints or dyes may be applied to areas of the polarizing-reflecting material. It will also be apparent that a transparent photosensitive layer may be applied to said material and photographic prints produced thereon. If desired, one or more of the functional portions of Fig. 1 may be cut out of the supporting unit 24 and have any of the constructions of Figs. 7 through l0, without the reflecting element thereof, placed over the cut out portions. For projecting polarized rays on said portions, a projector of the type described herein could be positioned at the rear of the unit to provide, through a transmission system, changes somewhat similar to those of the reflection systems of the invention. Polarizing or retardation material used in the display unit may be of a type having a continuously varying orientation rather than the fixed orientations shown, for providing modified effects. It will further be apparent that any of the constructions of Figs. 7 through 10 could be made without the reflecting layer and could be applied to suitable reflecting areas of the display unit or panel by an adhesive associated with said constructions or separately applied.

For further modification of color eects, where bircfringement and polarizing elements are included in a projector, both elements may be mounted for movement.

Or, a plurality of optically aligned birefringent elements may be used, one or more of which are axially movable. The use of colors or tones in areas of the unit surrounding the polarizing-reflecting portions which are of lighter shade or hue than the extinction (dark) appearance of said portions provides an effect of motion, Le., swinging movement, in the portions during the change cycle thereof, above described. Shading applied to marginal areas of polarizing-reflecting lettering or figures, as in the word aero of Fig. l, also contributes to a visual sense of motion of said lettering or figures during the change cycle. This effect is enhanced by positioning differently oriented polarizing-reflecting areas adjacent one another. The use of complementary colors in polarizing-reflecting and surrounding portions may be used for contrast effects as well as other colors and contrasts in quality or intensity of color and the like.

Polarizers having various transmission properties may be employed in the polarizing-reflecting elements of a display unit or projector, or both. Where a maximum "dark" is desired at extinction relation of the axes, a polarizer providing a lower percent of transmitted light may be used. Where maximum brightness of reflected light is required at transmission relation of the axes, a polarizer providing a higher percent may be employed. Treatment of surrounding areas may well determine the type of polarizer to be used. ln general, polarizers transmitting 38% or greater of incident light have been found satisfactory. The aforementioned tendency of certain polarizers to transmit preferentially in certain wavelength K bands may, in addition to influencing choice of a light source, be employed of itself to provide color in polarizing-reflecting areas of a display unit or to reinforce or modify interference colors produced by the use of birefringent components in the system. Where a tint, dye or the like is used in the polarizing-reflecting assembly, as for example, in a surface layer to provide color by daylight, as above described, deep colors should be avoided in favor of pastel shades or too great absorption of incident polarized rays will occur during operation therewith of the polarizing projector. Furthermore, the colors utilized should preferably be within the preferential wavelength transmittal band of the polarizer, the preferential wavelength band of the light source means and, where a birefringent element is used, should reinforce interference colors produced thereby. Soft green, yellow-green, yellow or rose tints have been found to be satisfactory for this purpose. Any of the other components of the assembly may comprise such a tint or dye, if desired, as for example, to reinforce other color-providing means above described. Where lettering, figures, etc. of the display unit of Fig. l are shown as polarizing-reflecting portions, it will be understood that background areas may be of polarizing-reflecting construction and that said lettering and figures may be as described or formed of nonpolarizing materials.

In display units of the type described herein, marked contrast between polarizing-reflecting and adjacent areas is of extreme importance for heightened visibility of the polarizing-reflecting areas. Accordingly, colors or neutral tones employed in areas surrounding the polarizingreflecting portions are advantageously of low reflections or high absorption and "flat or matte surfaces are suitably provided in said surrounding areas. Treatment of these areas may be predetermined with respect to characteristics, i.e., predominant wavelengths, of the light source so that maximum reflectivity of the polarizingreflecting portions is accompanied by low reflectivity of the surrounding areas. Large surrounding White areas may well be avoided.

Where a sheet or film type of light polarizer has been referred to herein which comprises a transparent plastic support as, for example, a sheet of cellulose acetate or cellulose acetate butyrate to which a thin light-polarizing film such as oriented polyvinyl alcohol is bonded, a modification of this construction could be employed at reduced cost in a material of the present invention. This modification contemplates elimination of the abovementioned initially supporting plastic sheet and bonding of the polarizing film to a metallic surfaced paper or the ilte of any desired rigidity or flexibility. An inherently unsupported film is defined herein as one which, prior to a described construction, has not been laminated to a supporting material. Assuming such a paper having a metallic reflecting and preferably diffusing surface to be used, and tnyt a thin film of oriented polyvinyl alcohol is to be used in forming the light polarizer, a subcoat comprising polyvinyl alcohol is formed on the metallic surface. 'The inherently unsupported polarizing film is then laminated to the surface, using a polyvinyl alcohol dope or water as the laminating agent. The polyvinyl alcohol film may subsequently be treated with a polarizing dye or the lil-ze, or may be treated to become light polarizing prior to lamination by various methods known to the art. The exposed surface of the polarizing film may then be treated with any of the protective, diffusing or color providing coatings disclosed herein. Alternatively, the metallic reflecting layer may first be formed on the oriented film of polyvinyl alcohol as, for example, by any suitable method of forming a reflecting layer described herein, and the surface so formed may be bonded to the supporting paper. Another method would involve forming a rear surface-reflecting coating on a transparent base material and bonding the polarizing film to a subcoat formed on the front surface of said base material. If a paper is used as the supporting or backing material, it may advantageously be coated or impregnated with a substance to repel moisture and thus acquire hydrophobic characteristics. Where a birefringent layer is included in the construction, as for example an oriented film of polyvinyl alcohol, this layer could first be bonded to the metallic surface, as described relative to the polarizing film. The polarizing film could then be bonded directly to the birefringent layer using a polyvinyl alcohol dope or Water as the bonding agent. If other types of light polarizers requiring a supporting element are employed, it will be apparent that an opaque material, such as a paper, may similarly be used for the purpose. Thus, for example, if a light polarizer formed as a coating applied to a prepared surface and previously referred to herein is employed, such a coating could be applied to the metallic reflecting surface of the paper. Although the polarizing elements shown in Figs. 5 through l0 are represented as of substantial thickness, it is to be understood that they may either incorporate a transparent supporting layer or be relatively much thinner than shown and rely upon a backing material for the reflecting layer as a support. It is also to be understood that where the polarizer incorporates a transparent supporting layer, the reflecting layer may be in the form of a relatively thin reflecting coating applied thereto, as described herein. Thus, the actual and relative thicknesses of the layers in Figs. l through 5 are generally exaggerated and are only to be construed in an illustrative sense to indicate the type and relative location of components.

It is to be understood that the display area or assembly referred to herein does not necessarily have a planar working surface and that said surface may be curved or comprise portions which are curved or otherwise formed to provide a three-dimensional effect and that depolarizing and nondepolarizing portions may be included. Thus the display assembly may have a plurality of working surfaces, such surfaces being considered as those comprising an area or portion constructed and responsive to polarized light of the type described herein.

A light source employing a variably polarizing element which is rotated by other than electro-mechanical means may be employed where a less expensive projector is desired. As an example, a cylinder formed of lightpolarizing sections having different directions of polarizaaesaeai tion is suspended from a support having vanes formed therein. The support is rotatably mounted over a light source having a refiector so that light rays are directed through alternate polarizing sections during rotation of the cylinder, rotation occurring through action of heat from the light source relative to said varies in a manner known to the art. Alternatively, the rotating polarizer could be a frusto conical element formed from a suitably shaped area of polarizing sheet material. Such a polarizer would provide a continuous change of direction of polarization of the light rays during its rotation. It will be apparent that birefringent elements could also be similarly formed and rotated by heat actuated means for providing varying retardation of components of the light rays.

A rear reecting surface having particularly desirable properties of reflectivity and diffusion is that in which small dry metallic particles are applied to a prepared rear surface of a transparent material. This method is exemplified in constructions of Figs. through 10 wherein the reflecting layer is described as formed on a polarizing or birefringent element. A method of forming such a reflecting surface as a continuous process is as follows. A supply of transparent sheet material, such as a lightpolarizing film, is mounted on a feed roller and is metered through a suitably compartmented chamber. A thin coating of a transparent adhesive or bonding substance, such as a lacquer, is continuously applied to the sheet material. The coating is brought to a tacky condition, as by heat and/or air circulation means. Fine, dry metallic particles, such as powdered aluminum, are evenly applied to the tacky surface. These particles may suitably be blown upon the tacky surface by compressed ar means from one or more appropriately directed apertures to provide a fine dispersion or dusting on" of the particles. Alternatively, the chamber may be continuously filled with circulating particles or they may be applied by falling upon the surface from controlled feed means. During application of the metallic particles, the edges of the moving sheet material may advantageously slide upon or between strips of felt or the like so that a seal is formed to prevent the metallic particles from entering the area of the compartment facing the opposite side of the sheet material. After the metallic particles are applied, the tacky surface is at least partially hardened by heat and/or air circulation means and a protective coating is then applied to the exposed area of the metallic coating by any suitable method, such as by spraying a lacquer thereon. After suiciently hardening the bonding and protective materials, the coated sheet material may be wound on a takeup roll, preferably using a nonadhering paper between successive layers of the roll. Alternatively to employing an adhesive or bonding substance, where the construction of the sheet material permits, a surface thereof may be softened, as by a solvent or by heat, and brought to a suitable tacky condition for applicaton of the metallic particles. The above procedure is not necessarily limited to a continuous process or to the material described but may be applied in separate steps and to various light transmitting materials and products where such a reflecting coating is of advantage.

Various other modifications of the devices and systems described herein will be apparent. Accordingly, such examples as have been presented are to be regarded as illustrative and the invention may be otherwise embodied and practiced within the scope of the following claims.

I claim:

l. A composite sheet material comprising a light polarizing layer, and a light transmitting and diffusing layer, said layers being held together in bonded relation and said diffusing layer having an exposed surface area providng a given diffusion of incident light rays.

2. A composite sheet material according to claim l in which the light transmitting and diffusing layer comprises a color-providing substance.

3. A composite sheet material comprising in order of arrangement a light refiecting layer, a light polarizing layer, and a light transmitting and diffusing layer, said layers being held together in bonded relation.

4. A composite sheet material comprising a light polarizing layer, a birefringent layer, and a light transmitting and diffusing layer, said layers being held together in bonded relation.

5. A composite sheet material comprising a supporting layer, a light reflecting layer formed on said supporting layer, a light polarizing film bonded to said light reiiecting layer, and a light transmitting and diffusing layer formed on the exposed unbonded surface of said light polarizing film.

6. A composite light refiecting sheet material comprising a sheet-like base material, a reflecting layer formed on a surface of said base material, a subcoat bonding layer formed on said refiecting layer, and a light transmitting inherently unsupported oriented film bonded to said subcoat bonding layer.

7. A composite sheet material according to claim 6 in which a light transmitting and diffusing layer is formed on the exposed surface of the oriented film.

8. A composite light reecting and polarizing sheet material comprising a sheet-like base material, a reliecting layer formed on a surface of said base material, a subcoat bonding layer formed on said reflecting layer, and an inherently unsupported light polarizing film bonded to said subcoat bonding layer.

9. A composite sheet material comprising a sheet-like base material, a refiecting layer formed on a surface of said base material, a subcoat bonding layer formed on a surface of said base material, a birefringent layer, lightdiffusing means and an inherently unsupported light polarizing film, one of said brefringent layer and light polarizing film being bonded to said subcoat bonding layer and said birefringent layer and light polarizing film being bonded together.

10. A display device for use with a source of substantially white polarized light and means for varying the direction of the polarizing axis of said polarized light, said display device comprising a vertically extending support means, a display area mounted on said support means, isotropic image means forming a first part of the subject material carried by said display area, and a plurality of laterally disposed and at least in part contiguous isotropic and light-polarizing image means forming a second part of said subject material, said first part of the subject material appearing stationary when subjected to axially varying polarized light and said second part of the subject material appearing to undergo movement when subjected to said axially varying polarized light.

1l. A display device as defined in claim l0 wherein said isotropic image means constitutes a major portion of said subject material.

l2. A display device as defined in claim 10 wherein said isotropic image means is substantially opaque and said light-polarizing image means is substantially transparent.

13. A display device as defined in claim l0 wherein said isotropic image means is formed of nondichroic lightabsorbing densities and said light-polarizing image means is formed of dichroic differentially light-absorbing densities.

14. A display device as defined in claim 10 wherein said image means are substantially nonbirefringent.

l5. A display device as defined in claim l0 wherein said support means is formed of an opaque sheet material.

16. A display device for use with a source of substantially white polarized light and means for varying the polarizing axis of said polarized light, said display device comprising vertically extending support means, a display area mounted on said support means, isotropic image means forming a first part of the subject material carried by said display area, a plurality of laterally disposed and substantially contiguous isotropic and transparent light-polarizing image means forming a second and complementary part of said subject material, and rellecting means optically aligned with at least said light polarizing image means, said rst part of the subject material appearing stationary when subjected to axially varying polarized light and said second part of the subject material appearing to undergo movement when subjected to said axially varying polarized light.

17. A display device as defined in claim 16 wherein a frontal surface facing said light source comprises lightdiffusing means.

18. A display device for use with a source of substantially white polarized light and means for varying the polarizing characteristics of said polarized light, said display device being adapted to functionally reect light which is incident thereupon and comprising a generally vertically arranged support means, means providing a display area adapted to carry pictorial subject material mounted on said support means, nondichroic image-forming means providing a first part of the subject material carried by said display area, a plurality of laterally contiguous dichroic and nondichroic image-forming means providing a second and complementary part of said subject material, metallic diffusely light-reflecting means positioned behind at least said dichroic image-forming means, and lightdiffusing means incorporated with a surface of said display device, said first part of the subject material appearing stationary when subjected to axially varying polarized light and said second part of the subject material appearing to undergo movement when subjected to said axially varying polarized light.

19. A display device as defined in claim 18 wherein is included a source of polarized light focused to direct polarized light rays upon a frontal surface of said device at an acute angle.

20. A display device as defined in claim 19 wherein a substantially uniformly birefringent element is optically aligned with one of said source of polarized light and said dichroic image-forming means.

2l. A display device for use with a source of substantially White polarized light and means for varying the direction of the polarizing axis-of said polarized light, said display device comprising means providing a substantially planar display area, nondichroic density-providing means forming a major part of the subject material of said display area, a plurality of complementary laterally contiguous dichroic and nondichroic density-providing means forming a first minor part of said subject material, and a plurality of laterally contiguous dichroic density-providing means having relatively differing polarizing axes forming a second minor part of said subject material, said nondichroic major part of the subject material appearing stationary when subjected4 to axially changing polarized light and said first dichroic and said second dichroic and nondichroic minor parts being complementary to said major part and appearing to undergo movement when subjected to said axially changing polarized light.

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