GB2238643A

GB2238643A - Improvements in or relating to display apparatus

Info

Publication number: GB2238643A
Application number: GB8926949A
Authority: GB
Inventors: James Robert Callaghan
Original assignee: KINGSTON COMMUNICATIONS
Current assignee: KINGSTON COMMUNICATIONS
Priority date: 1989-11-29
Filing date: 1989-11-29
Publication date: 1991-06-05
Also published as: GB8926949D0

Abstract

A visual display unit comprises a light emission means (20a, 20b) and a mask (25), and the light emission means (20a, 20b) is of elongate form and rotates about an axis generally parallel to its elongate direction. The mask (25) is located radially outwardly of the path swept by said light emission means (20a, 20b) when said means (20a, 20b) is being rotated. The elongate light emission means (20a, 20b) may comprise a row or rows of light emitting elements, such as electric bulbs, light emitting diodes or optical fibres. In a preferred embodiment the mask (25) is cylindrical in form, the light emission means (20a, 20b) rotates within the mask (25) and the mask (25) includes patterns of different light transmission characteristics over its surface. The mask (25) may be rotated in the same direction as, or in the opposite direction to, the light emission means (20a, 20b) and at a different speed to said light emission means. <IMAGE>

Description

"IMPROVEMENTS IN OR RELATING TO DISPLAY APPARATUS" This invention relates to display apparatus and, more particularly, to a display apparatus in which a visual display changes in accordance with a pre-determined programme.

It is well known in the art to pr ide a visual display by illuminating one or a plurality of light sources in an array of light sources and to vary the display by changing the pattern of the illuminated light sources in accordance with a pre-determined programme.

An object of the present invention is to provide a visual display apparatus in which the display can be varied in accordance with a pre-determined programme whilst the light sources are permanently illuminated.

According to the present invention there is provided a visual display apparatus comprising a light emission means and a mask, said light emission means being of elongate form and rotatable about an axis generally parallel to the elongate direction of said light emission means, and said mask being spaced radially outwardly of the light emission means so as to be swept by said light emission means when said light emission means is being rotated.

Preferably more than one light emission means is provided, said light emission means are substantially identical in construction and said light emission means are arranged to rotate about a common rotational axis and are equally space from said said axis.

Preferably said light emission means are equally spaced apart circumferentially of the swept path of said light emission means.

In a preferred embodiment in accordance with the invention a light source, such as an electric bulb, directs light through one end of each fibre in a bundle of optical fibres, said optical fibres extend to said swept path of the illumination source and the light emitting from the ends of the optical fibres in said swept path defined the light emission means.

In another embodiment said light emission means may comprise a row, or a plurality of rows, of electric bulbs or light emitting diodes (LED's).

The, or each, light emission means may include a diffuser plate, radially outwardly of the light emission means, and arranged to diffuse the light from said light emission means to give the appearance of a continuous light emission density along the length of said light emission means.

The mask preferably includes patterns of different light transmission characteristics over its surface such that, when swept by a light emission means, the light patterns through the mask vary in dependence upon the position of the light emission means relative to the mask.

In a preferred embodiment the mask is displaceable relative to the light emission means and, in a most preferred embodiment, the mask is cylindrical in form and arranged to rotate about the axis for rotation of the light emission means.

With such a most preferred embodiment the mask is preferably rotated in the same rotational direction as the light emission means but at a different rotational speed than said light emission means.

In another embodiment in accordance with the invention the apparatus includes a diffuser panel or plate so positioned that the light transmissions through the mask are viewed through the said diffuser plate or panel.

The present invention will now be described further by way of example with reference to the accompanying drawings in which : Fig. 1 shows, diagrammatically, a cross-section through a display apparatus in accordance with the invention on the line II-II in Fig 2, Fig. 2 shows a cross-section through the apparatus on the line III-III in Fig. 1 and, Fig 3 shows, in perspective view, an end region of one light emission support.

In the illustrated example a shaft 11, supported in bearings 12 and 13, is arranged for rotation by a motor 14 via a coupling 15. Two carrier links 16 and 17, secured on the shaft 11 in spaced apart relationship, carry two light emission supports 18 and 19 at locations equally spaced from the rotational axis of the shaft 11, said light emission supports being parallel to the axis of shaft 11 and carried by the links 16 and 17 to be diametrically opposite with respect to the axis of the shaft 11.

One end lia of the shaft 11 has an axial bore 11b which extends from said end ila to a slot 11c passing through the shaft 11 at or about the mid-length of the shaft 11 between the links 16 and 17 A bundle of optical fibres 20 is located in the bore 11b such that each fibre has an optical end open at the end 11a of the shaft 11, and the bundle of optical fibres 20 is split into two equal bundles 20a and 20b in the channel llc to allow one bundle of optical fibres 20a to pass from the slot 11c radially to the light emission support 18 and an equal bundle of fibres 20b to pass from the slot 11c radially to the light emission support 19.

At the light emission support 18 the optical fibres in the bundle 20a are distributed substantially uniformly along the length of the support 18 with their light emitting ends in a common plane facing radially away from the rotational axis of shaft 11. In like manner the optical fibres in bundle 20b are distributed substantially uniformly along the length of support 19 and have their light emitting ends lying in a common plane facing radially away from the axis of shaft 11.

The end regions of the optical fibres in the bundles 20a and 20b are, in the illustrated example, retained with their respective supports 18 and 19 by a suitable adhesive.

An electric bulb 21 is located adjacent the end lia of shaft 11 and the light emitting from bulb 21, when said bulb is illuminated, is focussed by a cone 22 surrounding the bulb 21 to direct the light from the bulb 21 onto the ends of the optical fibres exposed on shaft end gila. Thus, with the bulb 21 illuminated, light falling on the exposed ends of the optical fibres 20 exposed at the end 11a of shaft 11 passes along said fibres and is emitted radially outwardly from the ends of the fibres 20a, 20b attached to the supports 18 and 19 respectively and, because of the elongate form of supports 18 and 19 and the distribution of the optical fibres there-along the light emitted from each bundle of fibres 20a and 20b is in the form of a narrow, elongate illumination of substantially uniform density along the length of the said supports 18 and 19.

Two cylindrical end plates 23 and 24, each having a central boss 23a, 24a respectively are rotatably supported on the shaft 11 inwardly of but adjacent the bearings 12 and 13 and the said plates 23 and 24 support a cylindrical mask 25.

The boss 23a includes a pulley 26 rotated by an endless band 27 which passes over the drive pulley 28 of a motor 29.

Thus, when the motor 29 is energized to rotate pulley wheel 28, driver is transmitted through endless band 27 to the pulley 26, whereupon the pulley 26, end plate 23, mass 25 and through mass 25 the end plate 24 are rotated on the shaft 11.

In use, the bulb 21 is permanently illuminated and light is transmitted along the bundle of optical fibres 20 to the bundles 20a and 20b and light is emitted from the ends of the optical fibres in bundles 20a and 20b exposed radially outwardly of the supports 18 and 19 to define two narrow but elongate bands of light spaced apart, relative to the axis of shaft 11, at 180 degrees. When the motor 14 is activated to rotate the shaft 11 the narrow elongate bands of light emitting-from the optical fibres rotate about the axis of shaft 11 and, when the shaft 11 is rotated at speeds in excess of 25, revolutions per second without the mask 25 the eye would see the rotating displays as a continuous cylinder of light.

With the mask 25 static the two light emitting sources, continuously rotating, would be seen through the mask with the appearance of a permanent display, being dependent upon light transmission characteristics of the pattern defined by the mask 25.

However, when the motor 29 is activated to rotate the mask 25, in the same rotational direction as the shaft 11, the mask, from a viewpoint, gives a continuously changing pattern of light transmission.

When the drum 25 is rotating the degree of pattern change is dependent upon the rotational speed of the mask 25 relative to the rotational speed of the shaft 11.

Consider a single light source, 18 or 19, rotating at 50 revolutions per second so that the eye views the light source as a continuous cylinder of light. If now the drum 25 is rotated in the same direction as the light source the circumferential length of the drum visible to the eye will be dependent upon the relative speeds between the drum 25 and the shaft 11. Thus, if the drum 25 is rotated at a speed 10% lower than the light source the light source will sweep only 10% of the circumferential length of the mask 25 each revolution, 5% to each side of the vertical centre line through the rotational axis, and with the shaft 11 and the mask 25 rotating at such high speeds when viewed by the eye a pattern in the 5% to one side or the other side of the vertical centre line will appear to be the pattern of the whole of the area of the drum in view. As the difference between the speed of the mask 25 and the shaft 11 reduces the smaller will be the circumferential length of the mask 25 swept per revolution and, therefore, the greater the variety of the pattern which can be exposed to view.

In another arrangement the light source and the mask can be rotated at speeds slower than 50 revolutions per second and viewed through a diffuser plate (not shown). With such an arrangement the light sources to the eye will sweep from top to bottom, or bottom to top, of the diffuser plate through the mask, whereupon the visual aspect will appear as differing patterns sweeping the diffuser plate.

Whilst the present invention has been described with reference to specific embodiments the invention is not limited thereto and many modifications and variations will be apparent to persons skilled in the art.

Claims

PLAZAS

1 A visual display unit comprising a light emission means and a mask, said light emission means being of elongate form and arranged to rotate about an axis generally parallel to its elongate direction and said mask being located radially outwardly of the path swept by said light emission means when said means is being rotated.

2 A visual display unit as claimed in claim 1 wherein said elongate light emission means comprise a row or rows of light emitting elements assembled to define said elongate light emission means.

3. A visual display unit as claimed in claim 2 wherein said light emission elements comprise electric bulbs.

4. A visual display unit as claimed in claim 2 wherein said light emission elements comprise light emitting diodes.

5. A visual display unit as claimed in claim 2 wherein said light emitting elements comprise ends of optical fibres and the other ends of said optical fibres are exposed to a light emitting source.

6. A visual display unit according to any preceding claim wherein the light emission means include a diffuser plate, radially outwardly of the light emission means.

7. A visual display apparatus according to any one of the preceding claims wherein the circumferential width of the light emission means is less than the circumferential width of the mask when viewed along the axis for rotation of said light emission means.

8. A visual display unit as claimed in any one of the preceding claims wherein the length of the mask, in the direction of the rotational axis for the light emission means, is greater than the axial length of the elongate light emission means and the mask is so axially located that the light emission means are always viewed through said mask.

9. A visual display unit as claimed in any one of the preceding claims wherein at least two elongate light emission means are arranged to rotate about a common axis, to sweep a common path and said means are arranged equally spaced apart circumferentially about the said common axis.

10. A visual display unit as claimed in claim 9, when dependent upon claim 4, wherein each of said light emission means is defined by the ends of a bundle of optical fibres and the other ends of all the bundles of optical fibres are gathered together and exposed to a single light emitting source.

11. A visual display unit as claimed in any preceding claim wherein the mask is of arcuate form, based on a radius greater than the radius swept by the light emission means, and the base radius for the arcuate mask has its centre concentric with the axis of rotation for the light emission means.

12. A visual display unit as claimed in any preceding claim wherein the mask is of cylindrical form and the light emission means are located within the mask and arranged to rotate about an axis concentric with the axis of the mask.

13. A visual display unit according to any preceding claim wherein the mask includes patterns of different light transmission characteristics over its surface.

14. A visual display unit according to any preceding claim wherein the mask is arranged for rotation about an axis concentric with the axis of the light emission means.

15. A visual display unit according to claim 14 wherein the mask is arranged for rotation in the opposite direction to the direction of rotation of the light emission means.

16. A visual display unit according to claim 14 wherein the mask is arranged for rotation in the same direction as the light emission means.

17. A visual display unit according to claim 16 wherein the mask is rotated at a faster speed than the light emission means.

18. A visual display unit according to claim 16 wherein the mask is rotated at a lower speed than the said light emission means.

19. A visual display unit according to any preceding claim wherein a diffuser plate or panel is so arranged that the mask is always viewed through said diffuser plate or panel.

20. A visual display unit substantially as hereinbefore described with reference to an as illustrated in the accompanying drawings.