GB2067138A - Erasable display device - Google Patents

Abstract

A device providing a display corresponding to selective pressure applied thereto includes a sheet of opaque material having a smooth surface and a sheet of translucent material having dye and a smooth surface. At least one of the sheets is of a pliable plastic and the sheets overlie each other with their smooth surfaces adjacent. The smooth surfaces are urged into intimate contact by selective pressure and adhere to each other, thereby maintaining a display until they are separated. Heating of the sheets prevents failure of the surfaces to adhere to each other upon the application of pressure. <IMAGE>

Description

SPECIFICATION Heatable luminescent erasable display device The present invention relates to a heatable luminescent display device. More particuiarly, the invention relates to an erasable luminescent display device which is heatable so that it functions properly in different temperatures.

Various types of display devices, including many toys, are in the form of writing pads or slates which are capable of exhibiting impressions or displays formed thereon. The slates or writing pads have the advantage that they may easily be erased to remove the impressions or displays recorded thereon by separating a film or sheet from a paraffin-coated surface which serves as a backing sheet. The film which is generally used for this purpose is a translucent sheet. Writing on the pad with the application of the requisite pressure causes an intimate contact between the translucent sheet and the paraffin-coated backing to make the backing visible through the translucent sheet. In this manner, displays or impressions are recorded on the pad.However, this arrangement generally does not permit effective printing with rubber stamps, or the like, since the requisite pressures are not achievable thereby.

In the known devices, the impressions recorded on the pad are generally dull and generally have a short lifetime due to the weak nature of the translucent sheet used therewith. The translucent sheet used is generally brittle and becomes soiled and creased with extended use.

Other forms of toys or recording devices are known which are more complex in construction than the aforedescribed pad. These recording devices do not provide an iridescent, luminescent or fluorescent sheet of material to provide a simple and inexpensive device which produces an iridescent, fluorescent of luminescent display at the points where impressions are formed thereon.

There have been various types of toys which children could use to practice drawing and/or writing. When the drawing is finished, the drawing or writing may be removed so that the toy may be reused. One of the most common of these toys was the "Magic Slate", which, at best, had but a limited life.

Children would quite often scrape the paraffin coating off the backing sheet which would destroy the toy. Furthermore, if the paraffin were eaten, the child could become quite ill.

Another toy of the same general type was provided in box form having a plastic face, a powdered metal within the box which tended to adhere to the face, and a stylus which was operated by knobs for selectively removing portions of the powder from the face. When the case or its face broke, the powder escaped and could injure anyone inhaling it.

It is generally known that when a material containing an iridescent dye or pigment is applied to an opaque surface, reflected rays of light appear to make such material glow. This general concept has been used in the manufacture of reflective types of signs, particularly signs providing a visual display at night, when illuminated by a beam of light.

Using this concept, it has been found that by appropriate selection of materials and pressure, an iridescent display or impression may be produced which will remain as presented for extended periods of time. The display may be removed when desired. A new display may be produced by the application of pressure. A device of this type may be used in many ways. One of the outstanding embodiments would probably be in toys for children, however.

Modern display devices of the aforedescribed type, as disclosed in United States patents Nos. 3,761,343, granted September 25, 1 973 to the present inventor, and 4,011,665, granted March 1 5, 1 977, utilize a sheet of translucent material and a sheet of opaque material, one sheet overlying the other so that the adjacent surfaces of the sheets form an interface. The interface surfaces are smooth, and at least one of the sheets consists of plastic: The interface surface of the plastic sheet has a characteristic which tends to cause the sheets to adhere to one another.

Although one of the sheets is plastic, the other sheet may also be plastic or any other suitable material. Both the sheets may be nonrigid, but at least one must be pliable. If both sheets are pliable or non-rigid, a rigid backing sheet is required. When both sheets are pliable or non-rigid, pressure against the outer surface or either sheet will cause a corresponding intimate contact at the interface.

The result is total reflection of light at the selected point or points of intimate contact at the interface which produces the display.

When the sheets are separated, the intimate contact at the interface is terminated and the display is erased.

A serious disadvantage of the modern type of device is that the translucent and opaque plastic sheets have properties and qualities which are completely altered with changes in temperature. The known modern devices are thus seriously deficient, since they do not function properly in all climatic conditions.

When the plastic sheets become cold, they acquire a brittle character. Selective pressure applied to one of the sheets will then not produce a display, since the sheets of the device will not adhere to each other at the points of contact, or anywhere else. The device thus does not operate to produce a display, unless the plastic sheets are at least at approximately room temperature, since, as mentioned, the plastic material of said sheets is briftle at could temperatures, below room temperature, sa that there is na intimate contact between the translucent and opaque sheets at their interface.

Another serious disadvantage of the modern type of device is that the translucent sheet is easily scratched and marred by the manual pressure of a rigid instrument applied by a usdr on its surface in order to produce a display. This spoils the presentation of a cre sited display or impression.

The principal object of the invention is to provide a display device which overcomes the disadvantages of similar types of prior art devices.

An object of the invention is to provide a display device for an erasable display, which device is kept at operating temperature as desired.

Another object of the invention is to provide a display device of which the translucent sheet is protected from scratching, marring, or the like.

Yet another object of the invention is to provide a display device which functions efficiently, effectively and reliably to provide an erasable display.

Another object of the invention is to provide a display device for providing an erasable iridescent, fluorescent, luminescent, or the like, display.

Still another object of the invention is to provide a display device for providing an erasable iridescent, fluorescent, luminescent, or the like, display, regardless of ambient temperatures below room temperature-and without scratching, marring, or thelike, of the translucent sheet.

Yet another object of the invention is to provide a display device which is non-injurious to health, although it presents an erasable display which is iridescent, fluorescent, luminescent, or the like.

In accordance with the invention, a display device for providing a display corresponding to selective pressure applied thereto comprises a sheet of opaque material having a smooth surface and a sheet of translucent material having a dye and a smooth surface. At least one of the sheets is a pliable plastic. The sheets overlie each other, with the smooth surface of each adjacent to, ånd in contact with, the smooth surface of the other and forming an interface. The smooth surfaces are urged into intimate contact with each other by selective pressure applied to one of the sheets to produce a display. The smooth surfaces adhere to each other-when in intimate-contact at the interface thereby maintaining a display.

The sheets are separable from each other to terminate the intimate contact at the interface and thereby terminate the display. A heating device is provided in operative proximity with both sheets for heating the sheets to prevent failure of the surfaces to adhere to-each other upon the application of pressure.

The dye may be dispensed throughout the translucent material and is an iridescent dye, fluorescent dye or a luminescent dye.

The sheet of translucent material has a pair of spaced substantially parallel surfaces, and the dye, which may be an iridescent dye, a fluorescent dye or a luminescent dye, may be applied to either of the surfaces.

In a preferred embodiment of the display device, one of the sheets is rigid and pressure is applied to the other of the sheets.

In another embodiment of the display device, the sheet of opaque material has a pair of spaced substantially parallel surfaces, and both sheets are pliable. A rigid backing sheet is provided at the surface of the sheet of opaque material opposite that adjacent the sheet of translucent material.

The sheet of translucent material has a pair of spaced substantially parallel surfaces. A translucent protective sheet of acetate is provided on the surface of the sheet of translu cent material opposite that adjacent the sheet of opaque material.

The heating device comprises a heating unit, a source of electrical energy, an electric switch and electrical conductors connecting the heating unit, the source of electrical en ergy and the electric switch in circuit whereby the source of electrical energy selectively ener gizes the heating unit to produce heat under the manual control of the switch.

In a preferred erribodiment, the heating unit comprises an incandescent lamp and a ther mal reflecting device for directing heat pro duced by the lamp to most of the sheets of opaque and translucent material.

In another embodiment, the heating unit comprises an electric grid adjacent the sheets of opaque and translucent material.

In a preferred embodiment, the source of electrical energy comprises a battery.

In order that the invention may be readily carried into effect, it will now be described with reference to the accompanying drawings, wherein: Figure 1 is a perspective view of an embod iment of the display device of the invention; Figure 2 is a cross-sectional view of the embodiment of Fig. 1, taken along the lines ll-ll, of Fig. 1; Figure 3 is a top plan view of the embodi ment of Fig. 1; Figure 4 is a bottom plan view of the embodiment of Fig. 1; Figure 5 is a cross-sectional view of the embodiment of Figs. 1 to 4, taken along the lines V-V, of-Fig. 3; Figure 6 is a perspective view of another embodiment of the display device of the in vention; Figure 7 is a cross-sectional view of the embodiment of Fig. 6, taken along the lines VIl-VIl, of Fig. 6;; Figure 8 is a cross-sectional view of the embodiment of Fig. 6, showing the relationship of the sheets when pressure is applied, so that an impression or display is proclucedj Figure 9 is a perspective view of the embodiment of Fig. 6, showing how the sheets of the display device are separated; Figure 10 is a view, taken along-the lines X-X, of Fig. 5; and Figure ii is a top plan view of another embodiment of the heating device of the display device of the invention.

The display device of the invention provides a display corresponding to selective pressure applied thereto. The pressure is applied, manually, via any rigid instrument 6r device such as, for example, a pointed rod of wood, soft metal, or the like, or a fingernail, or the like.

The point is rounded to avoid puncture or cutting of the sheet of the device to which pressure is applied.

The display device of the invention comprises a sheet 1 of opaque material (Figs. 1, 2 and 4 to 9) having a pair of spaced, substantially parallel, smooth surfaces 2 and 3 (Figs.

2, 5 and 7).

A sheet 4 of the translucent material (Figs.

1 to 3 and 5 to 9) has a pair of spaced, substantially parallel, smooth surfaces 5 and 6 (Figs. 2, 5 and 7).

At least one of the translucent and opaque sheets 4 and 1 is pliable and may comprise any suitable plastic material such as, for example, vinyl or acrylic. In the embodiment of Figs. 1 to 5, the translucent sheet 4 is pliable.

In the embodiment of Figs. 6 to 9, both the translucent and opaque sheets 4 and 1 are pliable.

The opaque sheet 1 of the embodiment of Figs. 1 to 5 may comprise any suitable plastic material such as, for example, vinyl or acrylic.

The sheets 4 and 1 are rectangular and have common dimensions, with the adjacent opposing edges thereof being held together by any suitable means such as, for example, tape. Any suitable retaining means such as, for example, metal or plastic clamps or channels 7 and 8 may be used for this purpose (Figs. 3 to 5).

The impressions or displays which are - formed are iridescent, luminescent or fluorescent and appear in a brilliant color. To achieve the luminescent effect, the translucent sheet 4 comprises a substantially transparent material provided with a luminescent'dye of any desired color dispersed therethrough or on either of its surfaces 5 or 6. A fluorescent dye may be dispersed throughout the sheet 4 or on either of its surfaces 5 or 6. An iridescent dye may be applied to either surface of the translucent sheet 4 or, preferably, dispersed throughout the translucent material before the sheet is made.

The sheet 4 is advantageously transparent and is provided with an iridescent, luminescent or fluorescent dye dispersed therethrough. While the sheet 4 may also be translucent, more brilliant displays are achievable when said sheet is transparent. A green or blue iridescent dye is dispersed throughout the sheet 4.

The sheet 1 is opaque and non-absorbent.

The opaque sheet 1 preferably is white or of a light color to take full advantage of the light reflecting characteristics of such colors. The smooth surface 2 of the opaque sheet 1 which faces the surface 6 of the translucent sheet 4 is a dispersive surface which causes parallel light impinging thereon to be randomly dispersed at different reflective angles.

The use of non-absorbent colors increases the amount of light which is reflected through the translucent sheet 4 to enhance the brightness or brilliance of the impressed information. A preferred material for the opaque sheet 1 is a white vinyl sheet. Where colored opaque dispersive sheets are used, it is preferable that both sheets 4 and 1 be of the same color or close shades thereof. This is to prevent excessive absorption by each sheet of the color light associated with the other sheet. When both sheets are of the same color, the translucent sheet 4 transmits the respective colored light and the opaque sheet 1 reflects the same light with minimal absorption.

The translucent and opaque sheets 4 and 1 overlie each other, with the smooth surface 6 of said translucent sheet adjacent to, and in contact with, the smooth surface 2 of said opaque sheet and forming an interface, as shown in Figs. 2, 5 and 7. The smooth surfaces 6 and 2 are urged into intimate contact with each other by selective pressure applied to one of the sheets 4 and 1, as shown in Fig. 8, resulting in a display, which is iridescent, fluorescent or luminescent, dependent upon the dye of the translucent sheet 4.

The surfaces of vinyl sheets have wetting characteristics. Thus, the sheets 4 and 1, when they are urged against one another in pressure relation, appear to have a wet surface therebetween. The wetting characteristic causes the two facing surfaces of the adjacent sheets to adhere to each other. The surfaces are advantageously smooth and pliable to an extent which permits adherence between the two sheets, to the extent that all residual air therebetween is forced out. The consequence of such an arrangement is the resulting change in the reflective characteristics of the interface between the two sheets. The opaque characteristic of the sheet 1 prevents light from passing therethrough and its non-absorbency causes the light to be reflected instead of being dissipated.Any material which exhibits the dispersive and wetting surface characteristics is suitable as the opaque sheet 1.

If both sheets 4 and 1 are pliable, as in the embodiment of Figs. 6 to 9, a rigid backing sheet 9 (Figs. 6 to 9) is provided at the surface 3 of the sheet of opaque material 1, as shown in Figs. 7 and 8., The surface~3 of the opaque sheet 1 is opposite its surface 2, which is adjacent the surface 6 of the translucent sheet 4. The rigid backing sheet 9 may comprise any suitable material such as, for example, plastic, wood, cardboard, or the like.

The rigid backing sheet 9 is adjacent to, and coextensive with, the opaque sheet 1 to provide a rigid support for facilitating the application of pressure to form depressions.

In accordance with the invention, atranslu- cent protective sheet of acetate 1Q, shown only in Figs. 2 and 7, in order to maintain the clarity of illustration, is provided on the surface 5 of the translucent sheet 4. The surface 5 of the translucent sheet 4 is opposite the surface 6 thereof adjacent the surface 2 of the opaque sheet 1 (Figs. 2 and 7). The protective sheet 10 prevents scratching or marring of the surface 5 of the translucent sheet 4 by any instrument, such as the instrument 11 (Fig. 6), utilized to apply pressure to said sheet to produce a display.

When the pointed or blunt instrument 11 is uitlized to apply pressure on the translucent sheet 4 to cause said sheet to abut against the opaque sheet 1 to form a desired display or impression 12, said translucent sheet is deflected or depressed, as shown at 1 3 in Fig.

8. Any suitable device for forming a depression may be utilized to impress a line or a complete figure on the sheets. Sufficient pressure must be manually applied via the instrument 11 to substantially reduce the gap or space 1 4 to zero distance and thereby expel the air layer along the portion which has been selected for producing a display or an impression (Fig. 8). The pressure applied to the translucent sheet 4 moves said sheet into intimate contact with the opaque sheet 1 at the portions where such depression occurs and the appearance of wetting results from the adjesion, between the surfaces 6 and 2 of the sheets 4 and 1, respectively. The effect of the adjesion or intimate contact at the selected portions, which have been depressed, is to modify the reflective properties of the translucent sheet 4 at its surface 6.The presence of an air layer 14 causes rays of light within the translucent sheet 4 to undergo multiple reflections due to the smooth surface 6 of said sheet. The reflective properties at the adhesion point 1 3 essentially become those of the smooth diffractive surface 2 of the opaque sheet 1. The opaque sheet 1 is this opaque and non-absorbent.

The translucent and opaque sheets 4 and 1, respectively, are separable from each other to terminate the intimate contact at the interface and thereby terminate the display or impression. The separation of the translucent and opaque sheets 4 and 1 from each other may be accomplished by moving the translucent sheet away from the opaque sheet, as shown by an arrow 1 5 in Figs. 2 and 7, moving the opaque sheet away from the translucent sheet, as shown by an arrow 1 6 in Figs. 2 and 7, or moving said sheets away from each other, simultaneously, as shown by the arrows 1 5 and 1 6 in Figs. 2 and 7, The translucent sheet 4 is shown being peeled off the sheet 1 in Fig. 9.The separation of the sheets 4 and 1 from each other in this manner terminates the adhesive contacts 1 3 therebetween at the interfaces thereof to restore the air spaces or gaps 14, and consequently terminates the iridescent, fluorescent or luminescent effect. The pad is then ready to be depressed along selected portions thereof by the instrument 11 to form a new impression 1 2 thereon. Separation of the sheets thus erases anything which has been recorded on the opaque sheet 1.

In accordance with the invention, a heating device is provided to heat both the opaque sheet 1 and the translucent sheet 4, as desired, to bring said sheets up to room temperature, and thereby permit operation of the display device when the ambient temperature is below room temperature. The display device may thus be operated under all kinds of temperature conditions. The heating device 17 (Figs. 2 and 5) or 17' (Fig. 11) is positioned in operative proximity with both the opaque sheet 1 and the translucent sheet 4 and functions to heat said sheets to prevent failure of the surfaces 6 and 2 of said sheets, respectively, to adhere to each other upon the application of pressure via the instrument 1 1, or the like.

The heating device 1 7 comprises a heating unit of any suitable type for heating most, if not all, of the opaque and translucent sheets 1 and 4. In the preferred embodiment of Figs.

2 and 5, the heating unit comprises an incandescent lamp 1 8 (Figs. 2, 5 and 10) and a thermal reflector 1 9 (Figs. 2, 5 and 10) for directing heat produced by said lamp to most, if not all, of the opaque and translucent sheets 1 and 4.

In the embodiment of Fig. 11, the heating unit 17' comprises an electric heating element 20, bent as a grid and positioned adjacent the opaque and translucent sheets 1 and 4. The heating devices 1 7 and 17' further comprise any suitable source of electrical energy 21, an electric ON-OFF switch 22 and electrical conductors 23, 24 and 25, as shown in Figs. 2, 5 and 11. The electrical conductors 23, 24 and 25 electrically connect the heating unit 1 8 (Figs. 2 and 5) or 20 (Fig. 11), the source of electrical energy 21 and the switch 22 in circuit with a signal lamp 26 (Figs. 2, 5 and 11).

The source of electrical energy 21 may comprise any suitable electrical power source such as, for example, a battery or batteries, a rechargeable battery or batteries, or a com mercial power source, although a battery is preferred. The source of electrical energy 21 selectively energizes the heating unit 1 8 or 20 to produce heat under the manual control of the switch 22. The signal lamp 26 is ON during energization of the heating circuit and thus acts as a reminder to anyone using the device to open the switch 22 when the user is finished with it and plans to put it aside. This avoids needless dissipation of the battery or batteries, if such are used as the energy source 21 and prevents a waste of energy when a commercial power source is used.

While the invention has been described by means of specific examples and in specific embodiments, I do not wish to be limited thereto, for obvious modifications will occur to those skilled in the art without departing from the spirit and scope of the invention.

Claims (16)

1. A display device for providing a display corresponding to selective pressure applied thereto, said device comprising a sheet of opaque material having a smooth surface; a sheet of translucent material having a dye and a smooth surface, at least one of said sheets being a pliable plastic, said sheets overlying each other with the smooth surface of each adjacent to and in contact with the smooth surface of the other and forming an interface, said smooth surfaces being urged into intimate contact with each other by selective pressure applied to one of said sheets to produce a display, said smooth surfaces adhering to each other when in intimate contact at the interface thereby maintaining a display, and said sheets being separable from each other to terminate the intimate contact at said interface and thereby terminate the display; and heating means in operative proximity with both said sheets for heating said sheets to prevent failure of said surfaces to adhere to each other upon the application of pressure.

2. A display device as claimed in claim 1, wherein the dye is dispersed throughout said translucent material.

3. A display device as claimed in claim 1, wherein the dye is an iridescent dye and is dispersed throughout said translucent material.

4. A display device as claimed in claim 1, wherein the dye is a fluorescent dye and is dispersed throughout said translucent material.

5. A display device as claimed in claim 1, wherein the dye is a luminescent dye and is dispersed throughout said translucent material.

6. A display device as claimed in claim 1, wherein said sheet of translucent material has a pair of spaced substantially parallel surfaces and the dye is applied to either of said surfaces.

7. A display device as claimed in claim 1, wherein said sheet of translucent material has a pair of spaced substantially parallel surfaces and the dye is an irridiscent dye and is applied to either of said surfaces.

8. A display device as claimed in claim 1, wherein said sheet of translucent material has a pair of spaced substantially parallel surfaces and the dye is a fluorescent dye and is applied to either of said surfaces.

9. A display device as claimed in claim 1, wherein said sheet of translucent material has a pair of spaced substantially parallel surfaces and the dye is a luminescent dye and is applied to either of said surfaces.

10. A display device as claimed in claim 1, wherein said heating means comprises a heating unit, a source of electrical energy, an electric switch and electrical conductors connecting the heating unit, the source of electrical energy and the electric switch in circuit whereby said source of electrical energy selectively energizes said heating unit to produce heat under the manual control of said switch.

11. A display device as claimed in claim 1, wherein one of said sheets is rigid and pressure is applied to the other of said sheets.

12. A display device as claimed in claim 1, wherein said sheet of opaque material has a pair of spaced substantially parallel sufaces and both said sheets are pliable, and further comprising a rigid backing sheet at the surface of said sheet of opaque material opposite that adjacent said sheet of translucent material.

1 3. A display device as claimed in claim 1, wherein said sheet of translucent material has a pair of spaced substantially parallel surfaces, and further comprising a translucent protective sheet of acetate on the surface of said sheet of translucent material opposite that adjacent said sheet of opaque material.

14. A display device as claimed in claim 10, wherein said heating unit comprises an incandescent lamp and thermal reflecting means for directing heat produced by said lamp to most of said sheets of opaque and translucent material.

1 5. A display device as claimed in claim 10, wherein said heating unit comprises an electric grid adjacent said sheets of opaque and translucent material.

16. A display device as claimed in claim 10, whereby said source of electrical energy comprises a battery.

1 7. A display device for providing a display corresponding to selective pressure applied thereto substantially as described herein with reference to the accompanying drawings.