CH688251A5 - Display device and field. - Google Patents

Description

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description

The present invention relates to a display element which can be used on its own as a display device, but is mostly used as a pixel in a field of such elements in order to form a variable display plate. It will be found that the invention is particularly useful for signs and displays that need to be viewed from a wide range of angles, such as bus destination signs.

The display element is preferably of the type in which a rotor disk defining a central plane is used, which has mutually opposite sides which contrast or correspond with its background, and which is rotatable about an axis of rotation approximately parallel to said central plane, around the light or dark Side of the disk in a viewing direction that is considered to be the axis of a viewing cone (which is not necessarily a surface of revolution) that surrounds the viewing direction. The stator that forms the background for each disk is colored dark so that it contrasts with the light side of the disk and matches the dark side of the disk. The light and dark sides are shown in the ON and OFF positions.

A light emitting diode (LED) associated with each disc is arranged so that it forms part of the pixel of the disc when the bright side is displayed (called the ON position), the LED being arranged and directed to be the the bright side of the window is illuminated when it is in the ON position. The LED is always on, so that it must be hidden from the viewer when the pane is in the OFF position.

"Forward" and "backward" are the directions from the display element to the viewer or the opposite direction.

A "field" is the entire bus sign or another display, which is composed of "subfields", each consisting of a row of individual display elements or individual elements.

An “LED” is also intended to include a group of such LEDs.

The “viewing direction” is the general center of the locations (projected onto a plane perpendicular to the viewing direction) from which the display element or any field of display elements is to be viewed.

The “viewing cone” surrounds the viewing direction and includes the projections of the positions from which the display element or a field of display elements is to be viewed on such a level.

In a preferred embodiment of the present invention, the angular range in which the illuminated panes can be viewed (in the top view) is approximately 150 = and is arranged approximately symmetrically with respect to the longitudinal axis of a bus to which the field is attached. However, the direct light from the LEDs

viewed over an arc of approx. 75 ° from the longitudinal axis on the side of the bus towards which the light from the LED is directed. This is useful because a bus sign is often viewed from the sidewalk. Thus, for buses intended for use in most countries except England and Australia, the 75 ° sector will be to the right of the center line of the bus, and to the left in England and Australia.

It is known to use such a disk, which is enlarged by the end of an optical fiber. See for example the patents: U.S. 4,974,353 of December 4, 90, Norfolk U.S. 5,022,171 of June 11, 91 to Norfolk et al. U.S. 5,055,832 of June 8, 91 to Browne

However, optical fibers that are suitable for viewing from a relatively small angle are less suitable than LEDs for viewing from a wide angle range. In addition, LEDs are significantly cheaper, so that a display application with LEDs can be implemented where a similar application with fibers would not be possible.

Rotating disc LEDs have been used in other patents. See, for example, U.S. Patent 5,050,325 dated September 24, 91. However, this patent does not provide for the LED itself to be covered by the pane, nor for viewing from a wide angle range. Therefore, the LED had to be switched off in the OFF state. When designing the present display element, it is assumed that the LED is constantly switched on while the pane is switched between the ON and OFF positions, so that the costs of a separate circuit for switching on and off for each LED are avoided. Such switching requires a complicated construction and causes costs.

Accordingly, it is an object of this invention to provide a display element for use alone or in a field of such elements, in which the appearance of a rotatable tilting disc in the ON orientation is enhanced by an LED, this LED in the OFF orientation must be hidden from the viewer by the pane, and the rays from the LED are directed so that they illuminate only the bright side of the pane associated with the LED and are directly visible.

An object of this invention is to provide a display element or array of such elements which allows viewing from a wide angular range in the ON position and obscuring the beams in a wide angular range in the OFF position, and preferably one by one the LED-illuminated disc reflects reflected rays within a sector in plan view, which is symmetrical with respect to the forward direction in plan view.

The “viewing direction of the pane” is understood here to mean the direction which is approximately perpendicular to the average position of the illuminated pane in the ON and OFF positions and perpendicular to its axis of rotation. This direction is not parallel

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to the disc in the ON and OFF orientation of the disc are slightly offset from each other to reduce the rotation to less than 180 °, using a magnetic drive for reasons related to the drive. If a field of display elements is used, the viewing direction is assumed to be perpendicular to the plane that approximates the geometric location of the field.

“Top view” is understood to mean the view in the direction that is perpendicular to the viewing direction and parallel to the central plane of a field. The top view of a bus is therefore roughly a vertical view, but in other applications it can have any orientation.

From what has already been said, it can be seen that for a destination sign of a bus or other vehicle, the plan view is approximately in a horizontal plane, and that the viewing locations for the direct viewing of the light from the LED are all on one side of the light viewing direction for the illuminated panes are located.

The display element according to the invention is characterized by the features of patent claim 1.

In one embodiment, the invention provides a display element suitable for use as a pixel in a field, which has a disc that is between an ON position (in which a bright side is shown to a viewer) and an OFF position (in which shows the observer a dark side) with an LED arranged to illuminate the bright side of the windshield in the ON position, and the element or field of such elements in the immediate vicinity of the windshield Busses (or other vehicle) can be arranged to be seen by pedestrians through them. The proximity of the display element to the windshield is only limited by the distance that is required to enable the movement of the windshield between the ON and OFF positions and the interaction between the windshield and the windshield due to static charge.

The closer the field is to the windshield, the wider the viewing angle can be.

An object of this invention is to provide a display element in which the light source is completely maintenance free and inexpensive compared to other designs.

An object of this invention is to provide a display element for producing a pixel which is suitable for relatively large, many pixel-wide fields (for example from 20 to 40 pixels) in order to provide a good resolution in the sense of providing a ratio in relation to the size of the field small pixel and a pixel that has a relatively large effective area to provide.

“Effective area” means the percentage of the shield area that is occupied by the bright areas of the panes when they are all in the ON position. This is a measure of the effectiveness of the sign, even though it may not be exactly accurate given the effects of the light effects of the LED and the preferred angle of the bright fields of the panes with regard to the viewing direction. The requirement to have as large an effective area as possible means that the use of rectangular elements is preferred, since these tend to have the best "packing density" and consequently ensure the largest ON area in a display. Due to the requirement to provide pixels that have a small area in relation to the size of the field, the use of square pixels is therefore obvious.

“LED” here refers to the chip that is built into a lens, although the chip plus lens are often referred to together as LED elsewhere.

The invention thus provides, in one embodiment, a display element or a row or array of display elements, the stator preferably being an open front housing, usually of approximately square shape, and a disc constructed to be about an axis rotates to show a light or dark side in the line of sight. (The background of the disk, viewed in the viewing direction, is typically colored in such a way that it contrasts with the light side of the disk and matches the dark side of the disk.) An LED belonging to the stator is arranged and provided with covering means that the beams The LED illuminates the bright side of the pane for viewers on both sides of the viewing direction. Suitable means prevent the rays of the LED from emerging in directions transverse to the direction of view.

The preferred drive for the disc is electromagnetic, according to methods well known to those skilled in the art. However, other drives can be used within the scope of the invention.

In a preferred embodiment of the invention, a printed circuit board ("PCB") is attached to one side of the disk and an LED is attached so that its rays illuminate the bright side of the disk when the latter is in the ON position. This depends on the position of the disc when it is ON. In the ON position, the bright side of the pane is preferably inclined slightly towards the LED, and the rays of the LED are directed transversely to the viewing direction. Suitable means, preferably a housing on the sides of the lens of the LED (with respect to the desired direction of the rays of the LED), and the printed circuit board («PCB») on the back prevent the escape of rays whose direction is very different from the desired direction of the Rays of the LED deviate. There is sufficient divergence of rays from the LED with respect to the desired direction of window illumination of the rays from the LED so that viewers on a sidewalk in front of the bus (on a selected side) can see the direct rays from the LED when the window is in in the ON position.

In the context of the invention, the wall does not have to be a printed circuit board (“PCB”). However, this is considered the cheapest because it is then convenient to

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Apply tall strips to the printed circuit board (“PCB”) to provide the leads for the LED.

Preferably, only one side wall instead of two is provided for each element or each row of elements. The opposite wall is then formed by the adjacent element or rows of elements in the direction of the radiation of the LED.

The drawings, which illustrate a preferred embodiment of the invention, show:

1 is a partial view of a row of display elements according to the invention,

2A shows an assembly of LED, lens and housing according to the invention,

2B shows a detail of the LED housing and the printed circuit board (“PCB”),

Fig. 3A is a section along line 3A-3A of Fig. 1 showing a section of a disk in the ON position showing its light side,

3B is a section along lines 3B-3B of FIG. 1 showing a section of a disk in the OFF position showing its dark side,

4 is a front view of a row of display elements;

5 is a schematic view of the front of a bus, the destination plate of which is formed by a field according to the invention,

6 is a schematic section of part of the bus and the shield, taken in a vertical plane along the longitudinal axis of the bus,

7 is a view showing the viewing angles for the illuminated spot and for the LED directly,

8A and 8C show arrangements of a field of a shield in a prior art bus,

FIG. 8B shows the arrangement of a field of display elements according to the invention, which is intended for comparison with FIG. 8A and shows an alternative to FIG. 6.

In the drawings, Fig. 1 shows a section of a row of display elements according to the invention. The stator 10 of each element is an open front housing with a base 12, side walls 14S and end walls 14E that extend forward from the base to define a square display element that has good packing density and the display area effectively exploited.

At diametrically opposite corners of the square element, supports 16 have bores 18 for receiving the spindles 20 of an indicator disc, which has a dark side 22D and a light side 22B. The disk is provided with a notch in FIG. 31 so that it can rotate past the then adjacent magnetic core 26 when moving between the limit positions.

The drive is preferably magnetic and a magnet 24 has a north-south axis transverse to the axis of rotation of the disk and is driven by switching the megnet cores 26B and 26D, which are always of opposite polarity but are switched to rotate the disk to cause. A permanent magnet 29, the polar axis of which extends in the viewing direction V and which is arranged in the center of the base plate 12, is provided to change the field generated by the cores 26 in order to ensure a better starting torque. The drive is preferably in accordance with the explanations of patent 3,518,664 by M.K. Taylor of June 30, 1970, the contents of which are incorporated herein. The polarities of the magnetic cores are switched by coils 28 surrounding them from a current source, not shown.

(A magnetically driven disc typically rotates between the ON and OFF limit positions by 160 ° to <180 °, since a full 180 ° rotation is difficult due to the lack of a (magnetic) starting torque.)

Magnet 24 is preferably included in the middle layer of a coated disk as described in U.S. Patents 3,953,274 and 3,871,945, both by Winrow et al., The contents of which are incorporated herein. However, the magnet can also be installed or fastened in another way.

Another magnetic drive or a non-magnetic drive can be used, all within the scope of the invention.

A side wall 30 is provided on one side of each element and extends forward from walls 22E and walls 22S. As indicated in FIG. 4, all of the walls 30 of a row of individual elements 10 can be connected to a single wall and the elements 10 can be connected to a single shape. Wall 30 is preferably a printed circuit board ("PCB"). An LED chip (not shown) and a lens 32 are fastened in a housing 34 on the wall opposite the pane. The LED is attached to the circuit board 30 by means of its anode and cathode 36 and 38 with foil conductors 40. The housing 34 is provided with an opening to allow the beams to be emitted from the LED in a small cone centered around an LED beam axis A which is transverse to the line of sight and is directed towards the pane. The disc (in the ON position) is slightly inclined towards the LED (by adjusting the length of core 26B), the end of which acts as a stop in the ON limit position of FIG. 3A, so that the bright surface 22B of the disc is visible through the around the LED beam axis arranged cone is illuminated by LED rays. The emergence of rays in undesired directions is prevented in the transverse direction by the opaque walls of the housing 34 (which has an open rear for the LED connections) and on the rear by the wall 30.

The direction of the LED beam axis depends on the position of the pane in the ON orientation, so that it is possible within the scope of the invention to change the angle of the pane and its bright side 22B, but in such a case the housing 34 would have to be changed again so that the rays on axis A illuminate the bright side 22B.

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It should also be noted that some rays from the LED can pass in front of the bright side of the pane (only in the ON position) so that they reach the viewer directly. (See arc DIR in Fig. 7 (approx. 75 °)).

On the other hand, the bright sides of the disc illuminated by the LED can be seen from any point of the symmetrical arc I.DISK from approximately 150 °.

The lens of the LED can be constructed in a manner well known to those skilled in the art to ensure a range of viewing angles DIR of approximately 75 degrees to the right of the longitudinal axis of the bus (Fig. 9) and to provide a range of viewing angles I. Ensures DISK of about 150 °, which is approximately symmetrical with respect to the longitudinal axis.

It is noted that the disc, in its OFF position, sufficiently prevents light from escaping in the line of sight or in the cone of view. The end of the core 26D stops the disk in the OFF position. The circuit board wall 30 prevents the lateral exit of rays from the LED in both positions of the pane.

Although a wall could be provided on the other side of the element, it is preferred to use only one wall 30 so that light leakage through the dashed wall 30A (Figures 1 and 4) is avoided, which is the wall 30 of the next adjacent element is on the side of the element opposite the wall 30.

Figure 4 shows a row of seven elements, with five of the elements showing the light side 22B and two of the elements showing the dark side 22D. Figure 4 also shows wall 30A of the next element in the field.

Fig. 5 shows a bus carrying a field that shows a destination. The schematic in FIG. 5 is not intended to represent an example of the ratio of pixel size to field size. In reality, the destination sign could be 20 pixels high and 40 pixels wide, for example.

FIG. 6 illustrates how close the field A can be to the windshield C in the bus B for viewing by a pedestrian through the windshield. This “close proximity” can be achieved due to the lighting generated by the LED inside the element.

The distance of the field and its display elements in the shield of a bus or other vehicle is also shown in FIGS. 8A and 8C (prior art) and FIG. 8B, which shows a field produced using elements according to the invention. The arrangement according to the prior art is shown in FIG. 8A. Here, a bus BA has a windshield CA and a dot matrix display (or windshield matrix display) AA which is arranged so that it can be viewed through the windshield CA. However, the AA indicator must be reset away from the CA window to allow the light sides of the panes to be illuminated by a lamp or

Lamps DA are illuminated. In Fig. 8B, the point field (or pane field) AB can be arranged as close to the windshield CB of the bus BB as the function of the panes in terms of the actuation of the panes and the avoidance of an interaction between the panes and the windshield due to a static Charging is allowed, as discussed below. (Since each pane according to the invention is illuminated by its own LED). It can be seen that the arrangement made possible by the display elements according to the invention allows viewing of the field AB from an angle range that is much wider in all directions than when viewing the field AA. Another example of the prior art is shown in Fig. 8C, in which the halogen lamp is located next to or behind the display AA and is arranged to shine on a mirror EC which is angular and / or shaped to be the reflected rays spread over the field. It is readily apparent from the geometry that, in the prior art device of FIG. 8C, the viewing angle range is significantly smaller than that of FIG. 8B, just as the prior art device of FIG. 8A has a smaller viewing angle range than that of FIG. 8B.

In addition, in the case of both devices 8A and 8C corresponding to the prior art, it should be noted that the panes of the field are illuminated unevenly, since the light beams travel a further way from their source to the upper end (or the “lamp-remote” side) of the field need to go to the bottom. In contrast, in the field according to the invention from FIG. 8B, the illumination is more uniform since each pane is illuminated by its corresponding LED. The proximity of the field to the window is limited by two criteria.

First, in some cases, the non-conductive windshield, especially if it is made of plastic, may tend to take up a significant static charge that, up to close proximity to the windshield, may interact with the static electricity that has developed on isolated portions of the windshield. kick and disrupt the function of the disc. Therefore, the location of the windshield must be a sufficient distance from the windshield so that this does not happen. In an exemplary embodiment only, washers with a diameter of 1.27 cm and a distance of 2.54 cm between the axis of rotation of the disk and the windshield C (or CB) were provided. (See also Figures 3A and 3B (which are not to scale)).

Second, there must be some distance between the location of the disc's rotation and the windshield (see arc EA in Figures 3A and 3B) for the disc to rotate.

The phrase "immediate proximity" is therefore subject to such first and second restrictions.

Thus, based on simple geometric considerations, it is obvious that the improved (near

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re) arrangement of the field and its elements on the windshield extends the possible angle of viewing the field.

The vertical field of FIG. 8B can be compared to the slightly inclined field of FIG. 6, although the expanded possible viewing angle is present in both variants. This is in contrast to the larger field-windshield distance of a state-of-the-art field that had to be reset by the windshield in order to take into account the presence of lighting attached to the bus that shines backwards onto the field.

Since the field according to the invention can be arranged close to the windshield, it often has to be curved in plan view so that it is adapted to the curved profile of the windshield. Therefore, the field is preferably composed of rows that are only one element wide, as in Fig. 6, and to the extent necessary to complete the assemblies of individual elements.

7 shows the preferred viewing angle range: I.DISK of approx. 150 ° for the illuminated panes and an asymmetrical viewing angle range DIR of approx. 75 ° for direct viewing of the LED.

The asymmetry shown is used where the neighboring sidewalk is to the right of the bus, i.e. in most countries except the UK and Australia. Buses for Great Britain or Australia can be produced in reverse from left to right using the “mirror image” elements. In some cases, the elements shown can simply be turned over.

There is no limitation on the shape of the disc, but a square or rectangular shape ensures more effective use of the space.

Although the axes of rotation of the disc are shown as diagonal, vertical or horizontal axes can be used in the invention. Thus, for example, the invention can be used with disks having vertical axes and elongated shapes as described in John Browne's U.S. Patent 4,577,427 issued March 25, 1986, the contents of which are incorporated herein by reference.

Although the ends of the magnetic cores 26B and 26D act as stops for the disk in the ON and OFF positions and thus determine the position of the disk in these positions, the stops can also be provided in other ways and the magnetic cores only for the magnetic drive be used.

Claims (21)

Claims 1. Display element which defines a viewing direction and an organ which can be moved between an ON position in which a bright side is shown in the viewing direction and an OFF position in which a dark side is displayed in the viewing direction , and a lighting means associated with said display element and arranged to illuminate said bright side when said organ is in the ON position. 2. Display element according to claim 1, characterized in that said lighting means is an LED. 3. Display element according to claim 1 or 2, characterized in that said movable member is a disc which has an axis of rotation which extends approximately transversely to the viewing direction. 4. Display element according to claim 3, characterized in that said disk is attached to a stator in such a way that it rotates through an angle between approximately 160 ° and 180 ° between an ON and an OFF limit position. 5. Display element according to one of claims 1 to 4, characterized in that said lighting means is covered in the viewing direction by said pane when the latter is in the OFF position. 6. Display element according to one of claims 3 to 5, characterized in that a stator is provided with an attached wall which extends in the direction of view in front of said axis of rotation, said LED being attached to said wall so that it is is in front of said disc when the latter is in the ON position. 7. Display element according to claim 6, characterized in that said wall is arranged so that it blocks the light from said LED in directions transverse to said viewing direction. 8. Display element according to claim 6 or 7, characterized in that said wall is a printed circuit board. 9. Display element according to one of claims 2 to 8, characterized in that said LED is contained in an opaque housing which allows the exit of rays from said LED in one direction, so that said bright side is illuminated. 10. row of display elements according to one of claims 1 to 10. 11. row of display elements according to claim 10, characterized in that each element comprises a disc which is designed so that it rotates through an angle between 160 ° and 180 ° between an ON and an OFF limit position about an axis is generally perpendicular to the direction of view, with a wall attached to one side of said row and running in front of said axis of rotation, for each of said display elements there is an associated LED attached to said wall and means for limiting the rotation of said disc between an ON position in which said LED is in front of said disc and is intended to illuminate the bright surface of the disc and an OFF position in which said disc is the light from said LED in the Line of sight are provided, said wall being shaped to emit the light from each LED that is transverse to said direction of view rt is covered. 5 10th 15 20th 25th 30th 35 40 45 50 55 60 65 6 11 CH 688 251 A5 12. row of display elements according to claim 10 or 11, characterized in that blocking means are provided for the light of said LED in directions transverse to said direction of view, said blocking means are all on the same side of the row. 13. row of display elements according to any one of claims 10 to 12, characterized in that said walls are interconnected so that they form a single wall on one side of said row. 14. Field with subfields consisting of display elements according to one of claims 1 to 9 and / or rows of display elements according to one of claims 10 to 13. 15. Field according to claim 14, characterized in that each wall hides light from the LEDs on each side transversely to the viewing direction. 16. Panel according to claim 14 or 15, characterized in that the sub-panels are arranged in rows and strips of the width of a single element form part of some of said rows. 17. Field according to one of claims 14 to 16, characterized in that blocking means are provided for the light of said LED in directions transverse to said viewing direction, which block light emitted in the transverse direction by the LED. 18. Target information plate of a vehicle, which consists of a field according to one of claims 14 to 17, characterized in that the target information plate is arranged behind the windshield of the vehicle and is visible through the windshield. 19. The destination information plate of a vehicle according to claim 18, characterized in that said field is constructed for attachment in the immediate vicinity of said windshield of the vehicle. 20. The destination plate of a vehicle according to claim 18 or 19, characterized in that said display elements are at a sufficient distance from said windshield so that an interaction between a static charge on said windshield and a static charge on one of said elements is avoided . 21. A destination plate of a vehicle according to any one of claims 18 to 20, characterized in that said windshield is curved in plan view and said field is formed from rows which are adapted to said windshield. 5 10th 15 20th 25th 30th 35 40 45 50 55 60 65 7