DISPLAY WITH AT LEAST ONE TRANSLUCENT FRONT PANEL LIT FROM BEHIND

Abstract: Display comprising at least one translucent front panel, on which a text of a figure has been placed or printed, said text comprising at least one seven element digit, the elements of which comprise two differently coloured surfaces adapted to filling out alternately an aperture in the front panel, which elements are rotatable about a shaft running parallel to the front panel, and in which display means for lighting the back board of the front panel are placed. To provide a display lit from the interior, by means of which both the front panel and the movable parts of the digits are to appear as transilluminated areas essentially without shadows from the interior parts of the display, the means for lighting the front panel are placed at some distance from the front panel and in such a way that their perpendicular projection on the front panel falls outside the circumference of the seven element digit and in that the differently coloured surfaces of the digit elements are placed symmetrically around the shaft of an at least partially translucent carrier body at a distance corresponding essentially to the distance of the lighting means from the front panel.

Description: DISPLAY WITH AT LEAST ONE TRANSLUCENT FRONT PANEL LIT FROM BEHIND The present invention relates to a display comprising at least one translucent front panel, on which a text or a figure has been placed or printed, said text comprising at least one seven element digit, the elements of which comprise two differently coloured surfaces adapted to fill out alternately an aperture in the front panel, which elements are rotatable about a shaft running parallel to the front panel, and in which display means for lighting the back board of the front panel are placed. Displays for price indication often use so-called seven digit elements composed by seven plate-shaped elements, which can be moved in such a way that in one position a light coloured plate is shown and in another position a dark coloured plate is shown. Displays with digits of this kind are known from DE-OS 27 06 653, 27 07 241 and 28 22 704. Other examples of displays comprising movable elements are disclosed in the specifications to US Patents Nos. 4,040,193 and 4,441,084 as well as in the specification to Australian Utility Model No. 35671/84. However, none of these examples relates to a display, in which the front plate is transilluminated, and in which the digit elements both in their active and in their passive positions are lit from behind. With known displays it is possible to get digits, which are transilluminated in their active position towards a dark, not illuminated background, or digits, which appear as black, non-luminous areas, but not displays, in which both the background and the digits are luminous, fx with different colours or with varying light intensity. The appearance and the legibility of such a display is considerably impaired, if the internal parts thereof cast shadow on the front panel, or if the front plate is lit by discoloured light. The object of the invention is to provide a display of the afore-mentioned kind, i.e. one having a front panel, which is lit from the interior of the display, and which display may comprise digits, the elements of which are also transilluminated from the interior of the display both in their active and in their passive positions. Both the front panel and the digits should be without any essential shadows or unevenly lit areas. The object is met by a display of the kind mentioned by way of introduction, said display being characteristic by means of the subject matter of the characterizing clause of claim 1. By placing the lighting means at some distance from the front panel an approximately even lighting thereof will result, even though they are placed outside the outline of the digits, particularly because the non-active board portion has the same distance from the front panel as the lighting means and consequently will not cast shadows on the front panel or throw any significant amount of light differing in colour from that of the front panel towards said panel. The translucent carrier bodies are as to lighting essentially neutral and cast no shadows. The display according to the invention is advantageous in that it can be used with nearly all colour combinations and all light intensities, for example white digits on a luminous, coloured background, coloured or dark digits on white background or coloured digits and background of different colour. A particularly advantageous embodiment of the display, in which the front panel and the lighting means are connected by means of girder means, which are in turn connected by means of carrier frames, through which the lighting means and the front panels are accessible, is described in claim 4. This arrangement makes the renewal of lamps or fluorescent tubes particularly simple and makes the removal of the front plate for cleansing a simple process. By the embodiment according to claim 4 also problems in connection with thermal expansion of the front panels and the bearing parts of the display have been effectively overcome. Other advantages and embodiments according to the invention will be seen from the dependent claims as well as from the following detailed description, in which an embodiment of the display according to the invention is described with reference to the accompanying drawings, in which fig. 1 is a perspective view through a display according to the invention, fig. 2 is a front view of a part of a display with a seven digit element, fig. 3 is a sectional view of the front panel along the line III-III of fig. 2, fig. 4 is a diagonal view of a rotatable element for the display according to fig. 1, fig. 5 is a longitudinal section through a two-sided display along the line IV-IV according to fig. 1, and fig. 6 shows the display according to fig. 5 seen from the end and with the end cover partly cut away. In fig. 1 of the drawing a part of a cross-section through the display according to the invention is shown. The display comprises as a part of its text one or more digits of the so-called seven element type. The display has a front panel 1, on which the remaining text or figures of the display have been printed. The display is therefore particularly suited for price indication or for showing the time for train departures or the like. In the front panel 1, of which a portion having a digit is shown seen from the front in fig. 2, seven oblong apertures 2 for each digit have been cut. The apertures are covered by board elements 3,4, which consist of two types depending on whether the element in question is to be active in order to form the desired digit or not. In fig. 2 the active board elements are numbered 3, whereas the passive ones are called 4. It will be seen that the digit formed in fig. 2 is a nine. The front panel 2 is translucent, to enable it to be lit from behind. The same applies to the board element 4, which, when lit from behind, has to appear with the same colour and light intensity as does the front panel. Another type of board elements are also translucent, but are of another colour than that of the front panel. They may also be somewhat wider than the front panel 2, whereby they will appear as protruding areas in comparison with the front panel. The relief effect achieved thereby contributes to increasing the legibility of the digits. The digit elements are shown in fig. 4 at a larger scale. The board portions 3,4 are fastened to a carrier body 5, generally in the shape of an H. In the middle of the center beam of the H a bearing 6 is provided, by means of which the element can be mounted on an pivot. The carrier body is made of a translucent material, preferably clear acrylic plastic. Around the bearing bore a possibly toothed driving wheel 7 likewise made of a translucent material is provided. To the carrier body a pair of studs 8 of magnetic material are fastened. These studs serve as a stop for a holding magnet for limiting the rotation of the element about the pivot as explained below. When lighting the board portion 4 from the portion connected with the carrier body, the shadow effect will be minimal, as the carrier body is translucent and because of the fact that the contact area due to the H-shape of the carrier body is small. The board portions are provided with bevelled edges 9, which makes it possible for the element to rotate in the apertures with a tight fitting leaving only a very narrow slit, through which light may penetrate or through which the interior of the display can be seen. Due to the fact that the seven digit elements are to be seen as one coherent digit, the distance between the apertures 2 should be as small as possible, and the rotating paths of the board portions 3,4 in relation to adjacent digit elements will therefore overlap each other. On account of the H-shape of the carrier body two closely placed digit elements may rotate without colliding, as the carrier body does not project outside the connection line between the ends of the board portions 3,4. Care should however be taken not to rotate two adjacent digit elements at the same time, as the ends of the board elements might thereby collide. The elements shown in fig. 4 are mounted on a carrier frame comprising side portions 10, end portions 11 and a cross wall. The frame is made from a translucent material, for instance clear acrylic board. The frame serves as a hold for the pivots 13, about which the elements rotate, for a permanent magnet motor for each element and for stop magnets 15 (fig. 3) limiting the rotating angles of the elements and keeping the elements in their end positions of their rotating movements, in order that vibrations or the like may not make the elements move the board portions out of level with the front panel 1. On the shaft of each permanent magnet motor a pinion 16 is mounted, said pinion being in mesh with the driving wheel 6 of the elements. As will be seen from fig. 3, which is a section through the front panel 1 at the end of the frame for a digit, the end portion has been partly cut away, whereby a digit element fastened to the side portion becomes visible and a stop magnet 15 becomes visible too. It should be noted that the permanent magnet motors placed on the side portions and on the cross wall are placed at a greater distance from the front panel than the pivots 13 in order to reduce the possibility of shadows forming on the front panel. The motors on the end portions 11 are, however, placed at the same level as the pivots 13 to make room for the lighting means. By placing the digit elements on a frame adhering to the front panel, the effect of differences as to thermal expansion between the front panel and the remaining parts of the digit will be minimal, and the rotatable elements will therefore be freely movable even with narrow tolerances, irregardless of whether the front panel on account of the sun is exposed to a considerable heating and a subsequent thermal expansion or not. As will be seen from fig. 1 the front panel 1 is placed in a groove 17 along the edge of a girder means 18. The girder means is provided with an additional groove 19 for holding a slide 20, on which the lighting means in the shape of a fluorescent tube 21 are mounted. The fluorescent tube is placed approximately at the same distance from the front panel 1 as the board elements that are not present in the cuttings in the front panel. These not active board elements cannot therefore cast shadow on the front panel from the light emitted by the lighting means. In a similar way and by means of an opposite girder means the other edge of the front panel is connected to another lighting means. To protect the movable parts of the display and the text and figures placed on the front plate, the display is surrounded by an external transparent tube 22 consisting of acryl or polycarbonate depending on whether greatest importance is attached to light constancy or impact resistance. The two girder means 18 are, as will appear from the longitudinal section through a double-sided display according to fig. 5, fastened at their ends to a pair of frames 23 forming closed frames around a central aperture 24, best seen in fig. 6, through which both the front panel 1 and the lighting means are accesible and possibly exchangeable. The fluorescent tube 21, which is placed on a slide 20, may be withdrawn lengthwise, the energy supply in the shape of a plug connection 25 being disconnected thereby. In the same way the front panels may be removed from their girder means for cleansing or inspection of the movable digits mounted thereon. The transparent tube 22 is mounted on the frames 23, and the central aperture of the frames is closed by means of a cover 26, which with an intermediate layer in the shape of a packing 27 with a rim engages the exterior of the tube 22. The end cover 26 may as shown in fig. 6 be provided with an air valve 28 with a filter to prevent dirt and small insects from penetrating into the interior of the display. Internal end plates 29 may be placed under the end covers 26, to which plates the various supply elements for the lighting may be mounted, such as energy supply transformers 30, or logical circuits or similar controlling equipment for movement of the movable digit elements. The display according to invention is suited for the the making of modular displays, which may be put on top of each other in a common frame, where the displays with • movable digits are combined with displays constructed in the same way, but where the front panels do not have movable digits but text and figures.

Claims: We claim: 1. Display comprising at least one translucent front panel, on which a text or a figure has been placed or printed, said text comprising at least one seven element digit, the elements of which comprise two differently coloured surfaces adapted to filling out alternately an aperture in the front panel, which elements are rotatable about a shaft running parallel to the front panel, and in which display means for lighting the back board of the front panel are placed, c h a r a c t e r i z e d in that the means for lighting the front panel are placed at some distance from the front panel and in such a way that their perpendicular projection on the front panel falls outside the circumference of the seven element digit and in that the differently coloured surfaces of the digit elements are placed symmetrically around the shaft of an at least partially translucent carrier body at a distance corresponding essentially to the distance of the lighting means from the front panel. 2. Display according to claim 1, c h a r a c t e r i z e d in that the carrier body comprises a translucent board in the shape of an H, to the center beam of which a possibly toothed driving wheel also made from a translucent material is fastened. 3. Display according to claim 2, c h a r a c t e r i z e d in that the driving wheel is in gear with a pinion mounted on the shaft of a permanent magnet motor, which motor is mounted on a frame likewise made from a translucent material and adhering to the front panel. " 4. Display according to any of the claims 1, 2, or 3, c h a r a c t e r i z e d in that the front panel and the lighting means are connected by means of girder means, in which the front panel is placed in a groove running in the lengthwise direction of the display, and in which the lighting means are running on a slide in another groove, the dislay comprising to parallelly running, opposite girder means connected at their ends by means of closed frames, through the central apertures of which the lighting means and the front panel are accessible. 5. Display according to claim 4, c h a r a c t e r i z e d in that the frames are surrounded and connected by a transparent tube, said tube being closed at the ends by means of covers fastened to the frames, the covers being provided with connection means for energy supply to the lighting means and the driving means of the digit element. 6. Display according to any of the claims 2-5, c h a r a c t e r i z e d in that two studs of a magnetic material have been mounted on the H-shaped carrier body. 7. Display according to any of the claims 1-6, c h a r a c t e r i z e d in that the driving means for the digit elements are adapted to move one of them at a time or at least adapted not to move two adjacent elements simultaneously. 8. Display according to any of the claims 2-7, c h a r a c t e r i z e d in that the carrier means of the digits and the frame for each digit are made of clear acrylic plastic. 9. Display according to any of the claims 1-8, c h a r a c t e r i z e d in that one board portion of the digit element is made from the same material as the front panel, while the other board portion is made from translucent plastic and is surface-coloured. 10. Display according to any of the claims 2-9, c h a r a c t e r i z e d in that the distance between the two board portions of a digit element approximately corresponds to the length of the board portions, that the shaft, about which the digit elements rotate, runs perpendicular to the longest dimensions thereof, and that the board portions are tapering at their ends.

Inventors: NIELSEN BOERGE LEIF, NIELSEN, BOERGE, LEIF
Applicants: NIELSEN BOERGE LEIF, NIELSEN, BOERGE, LEIF
Application year: 1989
Main classification: G09F9
IPC codes: G09F9, G09F13