EP0115502A4

EP0115502A4 - Coloured display.

Info

Publication number: EP0115502A4
Application number: EP19830902424
Authority: EP
Inventors: Jong Ronald De
Original assignee: Harwald Industries Pty Ltd
Current assignee: Harwald Industries Pty Ltd
Priority date: 1982-08-06
Filing date: 1983-08-05
Publication date: 1987-04-29
Also published as: GB2135807A; NZ205175A; JPS59501380A; WO1984000839A1; ZA835798B; GB2135807B; EP0115502A1; GB8408641D0

Description

COLOURED DISPLAY

FIELD OF INVENTION

This invention relates, to information displays of the kind having an array of individual elements each of which is capable of presenting a contrast to the other elements so that a selected pattern may be formed and to individual elements or modules for such displays.

BACKGROUND ART

In one prior art display, each element is in the form of a disc one face of which is differently coloured to the other. Each disc is so suspended that in a rest or null position all the discs present the same colour so that no information or pattern is visible. An electromagnetic arrangement is used to rotate each disc so that a particular pattern may be formed by rotating the reverse face of selected discs into view.

Such displays are used for a wide variety of purposes such as indicating the totalizator odds at a racecourse. Although the discs and related magnetic circuitry are quite simple in design and construction, the displays can only present one coloured pattern in contrast to a single back¬ ground colour.

It is an object of this invention to provide an improved display element having more than two colours and an improved information display having a plurality of such individual display elements which is capable of providing a multi-coloured pattern.

OMPI DISCLOSURE OF THE INVENTION

According to the invention there is provided a display element comprising: a base, a regular display body having more than two display faces each of which is differently coloured, said display body being rotatable with respect to the base about an axis parallel to and spaced from the display faces so that only one of the display faces is viewable from the front of the display element, and electro¬ magnetic means for rotating the display body with respect to the base whereby a selected one of the display faces can be viewed from the front of the display element.

According to another aspect of the invention there is provided a multi-colour display comprising:-

(i) an array of individual display elements each of which consists of a base, a regular display body having more than two display faces each of which is differently coloured, said display body being rotatable with respect of the base about an axis parallel to and spaced from the display faces so that only one of the display faces is viewable from the front of the display element, (ii) electro-magnetic means for rotating each body independently of the others, and, (iii) control means operative to rotate a pre-determined number of elements so that a pre-determined array of faces may be viewable.

Preferably, each regular display body is in the form of a cube which is rotatable about a central axis. The two sides perpendicular to the axis are not used for display purposes and four display faces are^'differently coloured. Throughout the specification, the term "coloured" embraces distinctive visual effects such as contrasting cross- hatching, dot arrays and the like as well as coloured surfaces coloured light sources and reflective surfaces of different kinds.

BRIEF DESCRIPTION OF THE DRA ING-S

In order that the invention may be more readily understood and put into practical effect, reference will now be made to the accompanying drawings in which:-

Fig.1(a) to (d) are plan, side, front and rear views of a display element for a multi-coloured display according to one embodiment of the invention, Fig.2 is a schematic plan view of three adjacent display elements, Fig.3 is a cut-away plan view of the display element shown in Fig. 1, Fig.4 is a circuit diagram of a first control system for rotating each display element,

Fig.5(a) to (d) shows the waveform sequences operative to rotate each display element of Figs 1 to 3 so as tσ present each face for viewing, Fig.6 is a side elevational view of a display element according to a second embodiment of the invention,

Fig.7 is a sectional view similar to Fig. 6 showing the electro-magnetic drive means, Fig»8 is a sectional view taken along lines B-B in Fig. 6, Fig.9 is a circuit diagram of a second control system which may be used to rotate the display element shown in Figs 6 to 8, Fig.10 is a schematic diagram of a multi-colour display embodying the display element shown in Figs 6 to 8, and.

Fig.11(a) to (d) shows the pulse sequences used to rotate the display element shown in Figs 6 to 8.

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OMFI t i- DESCRIPTION OF PREFERRED EMBODIMENTS

The display element shown in Fig. 1 consists of a cubic body 10 mounted for rotation about a central vertical axis 11 on a base plate 12 having electrical pins 13 for connecting the element to the electrical control circuit shown in Fig. 14.

The axis 11 passes through the top and bottom faces of the cube 10 which are not used for display purposes. The four display faces 14, 15, 16 and 17 are, in this instance, coloured red, white, blue and green respectively.

The display elements are mounted in a two dimensional array to provide the required display area and resolution. Conveniently, the array may consist of 6 columns of display elements with each column having 9 display elements.

A computer which has displays stored in its memory controls the operation of the circuit of Fig. 4 so as to rotate each of the cubes 10 so that each displays the required colour. In this instance, each cube is 40mm wide and the axes are spaced apart by 50mm to give a 10mm spacing between cubes for preferred resolution. To avoid collisions between adjacent cubes which would occur if cubes 18, 19 and 20 of Fig. 2 were to be rotated together, the cubes of the odd numbered columns are rotated first and then the cubes of the even numbered columns are rotated.

Each cube 10 is rotated by means of electro-magnetic attraction and repulsion generated by four bifilar wound coils Ll, L2, L3 and L4 on the base 12 shown in Fig. 3. Each bifilar coil has coil portions (a) and (b) shown schematically in Fig. 4 which allows the cube to be rotated in either a clockwise or anti-clockwise direction to ensure that the movement of the cube is the smallest possible to present a particular colour for viewing. A circular magnet or magnetic follower 30 is attached to the body 10 and sits on a bearing on the base 12, it has semi-circular pole-faces 31. 32.

The interconnection of the four coils Ll, L2, L3 and L4 for bi-directional control is shown in Fig. 4. The diodes D ensure correct polarity on the coils and prevent operation from an AC source. The common line 21 to coil portions (a) is connected to a switching device 22 which in this instance is a PNP transistor that is operative to provide a positive potential V+ on line 21. The transistor 22 is connected between supply line 23 having a positive potential V+ and ground 24 through diode 25.

As shown in Fig. 4, the lines 26, 27, 28 and 29 are each connected to a switching device 33, 34, 35 and 36 through terminals A, B, C and D respectively. The switching devices may be NPN transistors the bases of which are driven by a computer. Ground connections for these transistors are^* indicated by numeral 24. The coils (a) and (b) are so connected that any two opposing coils have opposite polarities when energised. The fields from the coils induce poles into the pole pieces around which they are wound to provide a pre-determined pole pattern and the magnet 30 swings into alignment therewith. The pole pieces are reference points at which a pre-determined pole pattern is thus defined.

If terminal A is grounded and a positive potential is applied by the switching device 22 to line 21, coil (b) of Ll and coil (a) of L3 will be energised by virtue of the completion of the circuit from terminal A (grounded) through line 26, coil (b) of Ll and coil (a) of L3 to line 21. Coil (b) of Ll will provide a south polarised field and coil (a) of L3 a north polarised field. The magnet 30 will then rotate until its north pole face will be adjacent Ll and its south pole face adjacent L3. The blue face 16 will then be viewable.

Rotation of the cube 10 through 90 degrees can be achieved by de-energising Ll and L3 and energising L2 and L4. This can be done in two ways using terminals B and D, If terminal B is grounded (and line 21 still at a positive potential), coil (b) of L2 will provide a south field and coil (a) of L4 will provide a north field. Grounding of terminal D will produce the opposite fields in coils (b) of L4 and coil (a) of L2.

Thus, if the blue face is to be replaced by the white face as the viewable face, terminal B is used to energise the coils. If the green face is to be viewed, then terminal is used to energise the coils.

The coils (a) and (b) of Ll, L2, L3 and L4 are driven in a pulsed mode by the computer and the waveforms shown in Fig. 5 show the pulses applied to the gates of the transistors connected to the terminals A, B, C and D. If blue is to be viewable, the computer provides the pulse sequence of Fig. 5(d) where terminal A is grounded by applying the 400 milli-second positive pulse to transistor 33. Terminals D and B are grounded in sequence by applying positive pulses of half the duration of the pulse to transistor 33.

Similar pulsing sequences are shown in Figs. 5(a), (b) and (c). In each case the controlling terminal is grounded (e.g. C in Fig. 5(b)) by applying the 400 millisecond pulse to its transistor and its reverse complement (e.g. A in Fig. 5(b)) is left at the chosen potential by not applying a pulse to its transistor. Appropriate impedance means may be provided to maintain each cube in its selected position so that pulsing may be discontinued once the desired array has been displayed.

The second embodiment of the display element shown in Figs 6 to 8 consists of a cubic body 50 mounted for rotation about a vertical axis 51 on a base 52 having electrical pins 53 for connecting the element to the electrical circuit shown in the bottom half of Fig. 9. The cubic body 50 has an open bottom face. As was the case with the first embodiment, the axis 51 passes through the top and bottom faces of the cube and the four display faces 54, 55, 56 and 57 are coloured respectively red, white, blue and green.

Upstanding from the base 52 is a tubular housing 67 in which are located four bi-filar wound coils 71, 72, 73 and 74 that"are evenly spaced around the axis 51 as shown in

Fig. 8. The coils 71-74 have a central pole 75, 76, 77, 78 respectively (see Fig. 8). Between each pair of coils there is a locking projection 63, 64, 65 and 66.

On the inside of the top face of the cubic body 50 there is a stem portion 58 which terminates with a square cross-section shaft 59. The stem 58 carries a pin 60 which serves as the axis of rotation 51. The pin 60 passes through a central aperture in the housing 57 and is secured to the base 52 by means of a cirσlip 61.

Slidably mounted on the shaft 59 is a magnetic follower 62 which has a north pole at one end and a south pole at the other. The magnetic follower 62 can move upward on the shaft so that its ends can be raised clear of the locking projections 63, 64, 65 and 66 (see Fig. 7). When the magnetic follower 62 is in its lower position the cubic body 50 cannot be rotated. Each coil 71-74 has coil portions (a) and (b) shown schematically in Fig. 9 which allows the cube 50 to be rotated in either a clockwise or anti-clockwise direction to ensure that the movement of the cube is the smallest possible to present a particular colour for viewing from the front of the element. The dot at each coil portion (a), (b) represents the start of each coil portion. Current flow through coil portion (a) of coil 71 will produce a north pole at the top of pole piece 75 and current flow through coil portion (b) will produce a south pole. Current flow in both coil portions (a) and (b) will leave the pole piece 75 without an induced pole.

The interconnection of the four coils 71, 72, 73 and 74 for bi-directional control is shown in Fig. 9. The diodes 80 ensure correct polarity on the coils and prevent operation from an AC source. The common line 81 to coil portions (a) and (b) is connected to a switching device 82 which in this instance is a PNP transistor that is operative to provide a positive potential on line 81. The transistor 82 is connected to supply line 83 having a positive potential and its base is connected through terminal 114 to a control system described in part below. A Diode 85 is connected between line 81 and ground 84.

As shown in Fig. 9, the lines 86, 87, 88 and 89 are each connected to a switching device 93, 94, 95 and 96 through terminals 100, 102, 101 and 103 respectively. The switching devices may be NPN transistors the bases of which are driven by the control system described below through terminals 110, 112, 111 and 113. Ground connections for these transistors are indicated by numeral 84. All the coils (a) and (b) are so connected that any two opposing coils have opposite polarities when energised as was explained above in relation to coil 71. The fields from the coils bring the magnetic follower 62 into alignment and hence present a selected face of the cubic body 50 for viewing.

A display device made up of a matrix of display elements can be controlled by the system shown in Fig. 10 which, in this instance, incorporates a block diagram representing the two circuits of Fig. 9. Appropriate display data pulses are entered into an 8-bit shift register 200 through line 201 in conjunction with a clock signal 202. The shift register 200 drives a display device 250 through the Darlington NPN transistor array 204.

Two display elements 250 may be coupled to an 8-bit shift register and for the whole display device a series of registers is used, each being fed by the data pulses through line 201 and a clock signal 202. Conveniently, the display data is in binary format so that a bit set at one will turn on the selective NPN transistor (93, 94, 95 or 96) in the array. Line 81 is effectively a strobe which is energised wherever the display elements are to be set and remains energised for the duration of time periods Tl and T2 in Fig. 11.

The pulse systems used to operate each display device are shown in Figs 11(a) to (d). Fig. 11(a) shows the pulse system that must be applied to terminals 110, 111, 112 and 113 of the Darlington Array to present the red face 54 for viewing. Similar Fig. 1Kb) relates to the white face 55, 11(c) to the blue face 56 and 11(d) to the green face 57.

In this embodiment the following relationship applies in relation to the face viewable and the pole piece over which the north pole of the follower is disposed that face is viewable:-

- m EAT OMPI Face Viewable- Pole Piece

Blue 75

White 76

Red 77

Green 78

If the red face is to be presented for viewing, the appropriate display data pulses are entered into register 200 to provide the pulse system shown in Fig. 11(a). During the first time interval Tl, the pulses applied to terminals 110 and 111 will turn on transistors 93, 94 and terminals

100 and 101 will be grounded. Coils 71(a) and 73(b) will be energised to produce a north pole at the top of pole piece 75 and a south pole at the top of pole piece 77. Coils 72(a) and 74(b) will also be energised to produce a north pole at pole piece 76 and a south pole at pole piece 78. If the magnetic follower 62 was disposed with its north pole over pole pieces 75 (and hence its south pole over pole piece 77) the magnetic follower 62 will be repulsed and will ride up the shaft 59 to free the ends of the magnetic follower 62 from the projections 63-66 so that the cubic body 50 may rotate anti-clockwise and it will settle with its south pole over pole piece 76 and its north pole over pole piece 78.

During the second time interval T2, terminal 100 remains grounded and thus pole pieces 75, 77 remain as north and south poles respectively.. Terminal 101 is no longer grounded nor is terminal 102 as pulses are not applied to terminals 111 and 112. However, a-pulse is applied to terminal 113 and thus terminal 103 is grounded. Energisation of coil 72(b) produces a south pole at pole piece 76 and energisation of coil 74(a) produces a north pole at pole piece 78. The magnetic follower 62 will then turn anti-clockwise with respect to Fig. 8 and once it is clear of projections 63 and _.65 the magnetic follower 62 will

OMPI be drawn down onto pole pieces 75, 77 with its north pole over pole piece 77.

At the completion of T2 the pulses are terminated and all the coils are de-energised so that rhe pole pieces are without an induced pole. However, the cubic body 50 cannot rotate as the magnetic follower 62 is held between the projections 63-66.

If the green face is now to be viewed, the pulse system of 1Kb) is utilised. Thus, a pulse is applied to terminals 110 and 113 to produce grounding of terminals 100 and 103. Coils 71(a), 73(b), 72(b) and 74(a) will be energised to produce a north pole at pole piece 75, a south pole at pole piece 77, a south pole at pole piece 76 and a north pole at pole piece 78. It will be recalled that at the end of the movement resulting from Fig. 11(a) pulses, the north pole of the magnetic follower 62 was over pole piece 77. As that pole piece (77) is now a south pole there will be no ^■ repulsion and the magnetic follower 62 will remain locked in position for the duration of Tl.

During the second time interval T2, a pulse is maintained at terminal 113 and a pulse is applied to terminal 112 so that terminals 102 and 103 are -grounded. Coils 72(b) and 74(a) remain energised so that the south pole at pole piece 76 and the north pole at pole piece 78 remain as before. Coils 71(b) and 73(a) are energised so that polarity of pole pieces 75 and 77 are reversed to give a north pole at pole piece 77 and a south pole at pole piece 75. The north end of magnetic follower 62 (which is overlying the now north pole at pole^' piece 77) will be repulsed and the follower will ride up shaft 59 whereupon it will rotate anti-clockwise until its north pole is over the south pole at pole piece 76.

OMPI The operation of the pulse sequences, sho'wn in Figs 11(c) and (d) follows the same lines as that described above for Figs IKa) and (b) and thus need not be described in detail. However, it is to be noted that the constant pulse at terminal 112 in Fig. 11(c) provides a north pole at pole piece 77 and a south pole at pole piece 75 during Tl and T2 which provides the basic field so that the magnetic follower 62 will ult-imately assume the required alignment of its north pole over pole piece 75. The short pulses at terminal 113 during Tl and at terminal 111 during T2 set up a north - south relationship between pole pieces 78, 76 and then reverse it to ensure that during either Tl or T2 the carrier will be moved to its desired position.

Similarly, the pulse sequences shown in Fig. 11(d) provide a north pole at pole piece 76 for Tl and T2 so that the magnetic follower 62 will assume the required alignment of its north pole over pole piece 76. The short pulses at terminal 112 during Tl and at terminal 110 during T2 set up the moving field as before.

Various modifications may be made in details of the design and construction of the element, its mode of operation and that of the multi-colour display itself. For example, the bifilar wound coils could be replaced by two normal coils which are driven by bipolar circuitry. Thus, the required magnetisation and reverse magnetisation of a pole piece would be achieved by reversing the direction of current rather than using a uni-direction current through oppositely wound coils. In such an^" arrangement, the pulse systems would remain as before.

The relative disposition of the coils and follower may be varied as required. In the first embodiment, the follower was disposed vertically and was surrounded by horizontal pole pieces. In the second embodiment, the pole pieces were- vertical and the follower was overlying them in a horizontal position. Just as effectively, the pole pieces could be located in different planes with the follower located therebetween. Furthermore the reference points may be located at each end of a pole piece rather than at only one end of a pole piece as is the case in the two embodiments described.

Although in both embodiments, the reference points about which the pole pattern is defined are the ends of the linear pole pieces this need not be so. For example, the pole pieces may be omitted altogether leaving the follower to be influenced by the field of the coil. In another modification, the pole pieces may be linear within the coil but carry an end piece angularly disposed thereto so that the follower need not be disposed in line with the axis of the coil.

Claims

1. A display element comprising: a base, a regular display body having more than two display faces each of which is differently coloured, said display body being rotatable with respect to the base about an axis parallel to and spaced from the display faces so that only one of the display faces is viewable from the front of the display element, and electro-magnetic means for rotating the display body with respect to the base whereby a selected one of the display faces can be viewed from the front of the display element.

2. A display element according to claim 1 wherein the regular body is a cube.

3. A display element according to claim 1 wherein the electro-magnetic means includes an array of reference points on the base or the display body, means for selectively inducing north or south poles at at least some of the reference points to define a pre-determined pole pattern and a magnetic follower on the display body or the base operative to align itself with the pole pattern so that a selected one of the faces of the display body is viewable.

4.- A display element according to claim 3 wherein there is a magnetisable pole piece at each reference point and wherein the means for inducing poles includes an electro-magnetic coil around each pole piece.

5. A display element according to claim 4 wherein the pole pieces and coils are mounted on the base and the magnetic follower is mounted on the display body. 6. A display element according 'to claim 4 wherein there is the same number of pole pieces as there are faces and wherein each pole piece has its own coil.

7. A display element according to claim 5 wherein the pole pieces are disposed transverse to the axis of rotation of the body and the follower is disposed along the axis of rotation.

8. A display element according to claim 5 wherein the pole pieces are disposed^' parallel to the axis of rotation of the body and the follower is disposed transverse to the axis of rotation.

9. A display element according to claim 8 wherein the follower overlies the pole pieces.

10. A display element according to claim 8 wherein the pole pieces are in spaced apart planes and the follower is disposed therebetween.

11. A display element according to claim 3 and further including means for locking the display body in the selected position until a new pole pattern is induced.

12. A display element according to claim 4 wherein there is a reference point at each end of each pole piece.

13. A display element according to claim 4 wherein there is a reference point at only one^" end of each pole piece.

14. A display element according to claim 4 wherein the reference point is not aligned with the axis of the coil. 15. A display element according to claim 4 wherein the coils are bifilar wound.

16. A multi-colour display comprising:-

(i) an array of individual display elements each of which consists of a base, a regular display body having more than two display faces each of which is differently coloured, said display body being rotatable with respect of the base about an exis parallel to and spaced from the display faces so that only one of the display faces is viewable from the front of the display element, (ii) electro-magnetic means for rotating each body independently of the others, and, (iii) control means operative to rotate a pre-determined number of elements so that a pre-determined array of faces may be viewable.

17. A multi-colour display according to claim 16 wherein the electro-magnetic means includes an array of reference points on the base or the display body, means for selectively inducing north or south poles at at least some of the reference points to define a pre¬ determined pole pattern and a magnetic follower on the display body or the base operative to align itself with the pole pattern so that a selected one of the faces of the display body is viewable.

18. A multi-colour display according to claim 17 and further including circuit means for applying to the electro-magnetic means signals which will induce the pre-determined pole pattern.

19. A multi-colour display according to claim 18 wherein the circuit means includes a Darlington transistor array that is operated by a pulse system to provide the signals which induce the pole patterns. 20. A multi-colour display according to claim 19 wherein the poles are induced by coils the windings of which are selectively energised by the circuit means .