EP0390270A1 - Tafel, insbesondere Schreibtafel - Google Patents

Tafel, insbesondere Schreibtafel Download PDF

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Publication number
EP0390270A1
EP0390270A1 EP90200689A EP90200689A EP0390270A1 EP 0390270 A1 EP0390270 A1 EP 0390270A1 EP 90200689 A EP90200689 A EP 90200689A EP 90200689 A EP90200689 A EP 90200689A EP 0390270 A1 EP0390270 A1 EP 0390270A1
Authority
EP
European Patent Office
Prior art keywords
photo
layer
luminescent
board according
sulphide
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Withdrawn
Application number
EP90200689A
Other languages
English (en)
French (fr)
Inventor
Jozef D'haene
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
HORIZON IMPORT-EXPORT
Original Assignee
HORIZON IMPORT-EXPORT
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by HORIZON IMPORT-EXPORT filed Critical HORIZON IMPORT-EXPORT
Publication of EP0390270A1 publication Critical patent/EP0390270A1/de
Withdrawn legal-status Critical Current

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Classifications

    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B43—WRITING OR DRAWING IMPLEMENTS; BUREAU ACCESSORIES
    • B43L—ARTICLES FOR WRITING OR DRAWING UPON; WRITING OR DRAWING AIDS; ACCESSORIES FOR WRITING OR DRAWING
    • B43L1/00—Repeatedly-usable boards or tablets for writing or drawing
    • B43L1/004—Repeatedly-usable boards or tablets for writing or drawing with illuminating devices
    • B43L1/006—Repeatedly-usable boards or tablets for writing or drawing with illuminating devices with luminescent substances

Definitions

  • This invention relates to a board, in particular a writing board comprising a base layer and a cover layer provided for erasably writing thereon.
  • Such boards are generally known. There are for example known white boards on which erasable texts or drawings can be written or drawn by means of filt-tip pens even of different colours.
  • An object of the present invention is to provide a board on which the texts or drawings present thereon are still visible in the dusk or even in the dark.
  • a board according to the invention is characterized in that a photo-luminescent layer is disposed between said base layer and said cover layer made of a transparent material, which photo-luminescent layer comprises photo-luminescent particles embedded in a polymeric layer.
  • a text or drawings applied on this board can be seen clearly in the dusk or even in the dark since said photo-luminescent layer provides a light emitting plane behind the transparent cover layer.
  • photo-luminescence light is agreable to look at and thus offers an advantage from an aesthetical point of view.
  • said photo-luminescent layer comprises from 30 to 95 % by weight and preferably from 40 to 60 % by weight of said photo-luminescent particles. Even if a relatively small amount of photo-luminescent particles is used, the photo-luminescent activity of said photo-luminescent layer is sufficient to make the applied texts or drawings in an agreable way visible in the dark. Moreover, a smaller amount of photo-luminescent particles improves the mecha­nical properties of the photo-luminescent layer.
  • said photo-luminescent particles have a diameter comprised between 5 and 100 microns.
  • Such small particles offer the advantage that they allow to obtain a homogeneous distribution of the photo-luminescent material over the photo-luminescent layer and they have a larger specific surface resulting in a higher photo-­luminescent activity and a more agreable appearance.
  • said photo-luminescent layer is an extruded layer.
  • Figure 1 shows a preferred embodiment of a writing board according to the invention comprising a frame 1 applied at least around the actual writing board 2.
  • the frame 1 can be made of any suitable material and can have any shape and dimensions according to its destination.
  • Figure 1 it shows for example a recess 3 provided for applying a sticker and a groove 4 for carrying a pen 5 to be used for writing on the board.
  • the board 2 is composed of different superimposed layers and comprises at least a base layer 6, a transparent cover layer 7 and a photo-luminescent layer 8 disposed between the base layer 6 and the cover layer 7.
  • the base layer 6 constitutes usually a support layer for the writing board 2. Preferably it is a dull layer in order to avoid that too much light would reflect on the writing board 2.
  • the base layer 6 may be formed for example of a film, a plate, a sheet, a woven or a non wover fabric, a felt or a wadding.
  • the base layer 6 may further comprise a more rigid layer which has not been shown in the figures and which is for example a part of the frame 1.
  • the photo-luminescent layer 8 comprises photo-­luminescent particles embedded in a polymeric layer. These photo-­luminescent particles are made of a photo-luminescent material. A large group of such materials are suitable for that purpose and they comprise for example zinc sulphide, selenide and telluride; cadmium sulphide, selenide and telluride; alkaline earth sulphide, selenide and telluride and mixtures thereof.
  • the photo-luminescent activity of all these materials is due to the presence of a metallic activator such as for example copper, cobalt or bismuth powders and mixtures thereof. All of these photo-luminescent materials have a particular body colour in the dark.
  • the photo-luminescent particles are embedded in the polymeric layer in the form of a fine powder, the particles of which have a diameter comprised between 2 and 200 microns and preferably between 5 and 100 microns. This can be done by means of an extrusion.
  • the thus obtained photo-luminescent layer 8 comprises from 30 to 95 % by weight and preferably from 40 to 60 % by weight of said photo-luminescent particles and has a thickness of 400 to 1200 microns. Two or more of such photo-luminescent layers can be superimposed.
  • the cover layer 7 is a transparent layer and is in particular transparent for the light emitted by the photo-luminescent layer 8.
  • the cover layer is made of a polymeric material. It may consist of one or several layers which have all to be transparent. A particular characteristic of this cover layer 7 is that text or drawings written thereon with the pen 5 can be wiped out. It's thickness is preferably comprised between 10 and 100 microns.
  • the polymeric material of the photo-luminescent layer 8 as well as of the cover layer 7 can be selected from the following polymers or copolymers : polyethylene, polypropylene, ethylene-propylene copolymers and other olefinic polymers and copo­lymers; vinyl-acetate polymers and copolymers (especially copolymers with ethylene and/or propylene); methyl-methacrylate polymers and copolymers and other resins coming from acrylic or methacrylic esters and nitriles; aromatic polycarbonates; thermoplastic polyurethanes; polyethylene terephthalate, polybutylene terephthalate and other crystalline aromatic polyesters; vinyl or vinylidene fluoride polymers and copolymers; polyvinyl-chloride; elastomeric polymers and copoly­mers and in particular ethylene-propylene elastomeric copolymers (EPM) or ethylene-propylene-diene elastomeric terpolymers and poly­
  • polypropylene, polymethylacrylate, polystyrene and high impact polystyrene are especially preferred.
  • the polymeric material of the photo-luminescent layer 8 may be different from the one of the cover layer 7. Both layers 7 and 8 can be glued to each other. If the compatibility of the layers with each other is however so that a good adhesion between the layers can be obtained, said board can be made by means of lamination, extrusion or co-extrusion or by means of a combination thereof.
  • two or more layers are applied to each other by leading them between the hot rollers of a rotary press (calender).
  • the photo-­luminescent layer 8 is extruded for example on the cover layer 7 or possibly on the base layer 6.
  • the co-extrusion method comprises the simultaneous extrusion of several layers which flow together into a single head wherein the stratified streams of the different components are superimposed to form a multilayer object.
  • the photo-luminescent layer 8 is preferably extruded. In order to get a product of good quality, this extrusion has to be carried out very carefully as will be explained hereunder.
  • the following successive steps are preferrably executed: - pre-mixing the photo-luminescent particles with said polymeric material, both in the powder form, the difference between the particle size of both of these powders being smaller than 10 % of the smallest size, preferably said particle sizes are substantially equal; this pre-mixing can be carried out for example in a rotary drum or in a tumbling drum; - feeding the obtained mixture to an extruder; - extruding this mixture very smoothly, i.e.
  • pellets or granules are fed via a second hopper, indicated in Figure 3 by reference 9, to a sheet co-extrusion unit 10 wherein a first extruder 11 forms the photo-luminescent layer 8.
  • a second extruder 12 is fed via a third hopper 13 the same isotactic polypropylene powder as used for the photo-­luminescent layer 8.
  • the extruded sheet obtained by means of this second extruder 12 forms the transparent cover layer 7 and is led together with the extruded photo-luminescent layer 8 into a co-­extrusion head 14 wherein a composite layer 15 consisting of the photo-luminescent layer 8 and the cover layer 7 is formed.
  • This compo­site layer 15 is led together with an opacified polypropylene layer 6, forming the base layer 6 and coming from a first roller 16 of a calender 17, between rollers 18, 19 and 20 and is at the same time cooled down.
  • the formed layer is then stretched by means of a train 21.
  • the thus obtained board 2 shows a wonderfull yellow afterglow persistent in the dark after exposure to daylight even for a time of 5 hours or more. Texts or drawings applied thereon are in clear contrast with the light-emitting photo-luminescent layer 8.
  • a board according to the invention can have many different shapes and can be used for various applications. It can con­ stitute the whole or part of differently shaped objects, for example toys, especially toys for teaching purposes; warning signals; direction signals; machine parts; dials or portions of a dials; sport equipments; switches and furnishings of rooms for example of dancing rooms.
EP90200689A 1989-03-31 1990-03-23 Tafel, insbesondere Schreibtafel Withdrawn EP0390270A1 (de)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
BE8900362A BE1003132A6 (nl) 1989-03-31 1989-03-31 Bord voor uitwisbare aantekeningen.
BE8900362 1989-03-31

Publications (1)

Publication Number Publication Date
EP0390270A1 true EP0390270A1 (de) 1990-10-03

Family

ID=3884104

Family Applications (1)

Application Number Title Priority Date Filing Date
EP90200689A Withdrawn EP0390270A1 (de) 1989-03-31 1990-03-23 Tafel, insbesondere Schreibtafel

Country Status (3)

Country Link
EP (1) EP0390270A1 (de)
JP (1) JPH03114791A (de)
BE (1) BE1003132A6 (de)

Cited By (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2000061382A1 (de) * 1999-04-07 2000-10-19 Katja Hardenfels Notizsystem, insbesondere für patienten- und pflegedaten
WO2005037925A1 (de) * 2003-10-22 2005-04-28 Studiengesellschaft Kohle Mbh Lunineszierende transparente kompositmaterialien
WO2010117100A1 (ko) * 2009-04-10 2010-10-14 (주)넥손 라이팅 보드
WO2011114325A1 (en) * 2010-03-13 2011-09-22 Uri Fisher Bidirectional illuminated display system and a method therewith for facilitating human interaction
WO2021052582A1 (fr) * 2019-09-18 2021-03-25 Biwi S.A. Objet manufacturé luminescent et son procédé de réalisation
DE202020004269U1 (de) 2020-10-10 2022-01-26 Hermedia Verlag Gmbh Löschbares Grafikfeld als Schiefertafelersatzprodukt
DE102020006228A1 (de) 2020-10-10 2022-04-14 Hermedia Verlag Gmbh Löschbares Grafikfeld als Schiefertafelersatzprodukt

Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB559124A (en) * 1942-08-25 1944-02-04 Arthur Marcus Rewald Improvements relating to writing tablets
FR2308155A1 (fr) * 1975-04-18 1976-11-12 Aerospatiale Procede et panneau d'affichage photoluminescent
FR2427211A1 (fr) * 1978-05-31 1979-12-28 Scerab Tablettes a usage graphique pour zone d'eclairement faible ou nul

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB559124A (en) * 1942-08-25 1944-02-04 Arthur Marcus Rewald Improvements relating to writing tablets
FR2308155A1 (fr) * 1975-04-18 1976-11-12 Aerospatiale Procede et panneau d'affichage photoluminescent
FR2427211A1 (fr) * 1978-05-31 1979-12-28 Scerab Tablettes a usage graphique pour zone d'eclairement faible ou nul

Non-Patent Citations (1)

* Cited by examiner, † Cited by third party
Title
PATENT ABSTRACTS OF JAPAN vol. 6, no. 239 (C-137)(1117) 26 November 82, & JP-A-57 139171 (NIPPON DENSHIN DENWA KOSHA) 27 August 82, *

Cited By (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2000061382A1 (de) * 1999-04-07 2000-10-19 Katja Hardenfels Notizsystem, insbesondere für patienten- und pflegedaten
DE19915680B4 (de) * 1999-04-07 2005-11-17 Katja Hardenfels Nicht-elektronisches Notizsystem für insbesondere Patienten-und Pflegedaten
WO2005037925A1 (de) * 2003-10-22 2005-04-28 Studiengesellschaft Kohle Mbh Lunineszierende transparente kompositmaterialien
WO2010117100A1 (ko) * 2009-04-10 2010-10-14 (주)넥손 라이팅 보드
WO2011114325A1 (en) * 2010-03-13 2011-09-22 Uri Fisher Bidirectional illuminated display system and a method therewith for facilitating human interaction
WO2021052582A1 (fr) * 2019-09-18 2021-03-25 Biwi S.A. Objet manufacturé luminescent et son procédé de réalisation
DE202020004269U1 (de) 2020-10-10 2022-01-26 Hermedia Verlag Gmbh Löschbares Grafikfeld als Schiefertafelersatzprodukt
DE102020006228A1 (de) 2020-10-10 2022-04-14 Hermedia Verlag Gmbh Löschbares Grafikfeld als Schiefertafelersatzprodukt

Also Published As

Publication number Publication date
BE1003132A6 (nl) 1991-12-03
JPH03114791A (ja) 1991-05-15

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