GB2270189A

GB2270189A - A display or sign.

Info

Publication number: GB2270189A
Application number: GB9218420A
Authority: GB
Inventors: Paul Grosvenor
Original assignee: THERMOTOR Ltd
Current assignee: THERMOTOR Ltd
Priority date: 1992-08-29
Filing date: 1992-08-29
Publication date: 1994-03-02
Also published as: GB9218420D0

Abstract

An illuminated sign is provided in which the sign face 10 has an array of pixels 11 which are fed via an optical fibre harness 20. Between the light source 12 and the sign face 10, the harness is interrupted by a gap and a coded punched tape 22 run through the gap. The punched tape 22 has coded holes punched in it to determine what is shown on the sign face. An electronic controller coupled to an aspect or datum sensor is used to control the position of the tape and the switching on and off of the lights, which are switched off during movement of the tape. <IMAGE>

Description

"A DISPLAY OR SIGN FACE" This invention relates to a display or sign face comprising a matrix of points, known as pixels, which may be selectively illuminated to display a selected letter, number or other symbol or pattern.

An object of the invention is to provide means to select the particular letter, number or other symbol or pattern which can be operated quickly and accurately.

According to this invention, there is a display or sign face comprising a matrix of points, or pixels, which may be selectively illuminated to display a selected letter, number or other symbol or pattern, light being supplied from a light source through a harness of input optical fibres, the free ends of which are supported in a block, a second harness of output optical fibres being provided to convey light from a second block to the matrix of points or pixels on the display or sign face, the first and second blocks lying closely adjacent each other and a coded punched tape bering located in a gap between the two blocks, the punched tape incorporating a series of groups of punched holes which allow light from selected input fibres to enter selected output fibres so as to display a particular letter, number or other symbol or pattern.

The tape is preferably carried on motor-driven spools and its position is determined by an electronic controller which receives signals from an aspect or datum sensor to indicate the position of the tape.

Preferably the controller includes means to switch the light source off during movement of the tape and to switch it on when a selected point on the tape is reached.

The electronic controller includes means to operate one or more drive motors to move the tape.

The light source is preferably in the form of a light box with fibre harnesses connected to two sides of the box and two sources of light being located in the other two sides of the box, the light being directed through a splitter so that each harness receives part of the light directly from one light source and a second part of the light indirectly from the other light source. The splitter may, for example, be a splitter mirror or a split fibre harness, or other means of sharing light.

There may be a number of light boxes or a single light box and the light box or boxes may be provided with two sets of colour filters which may be interposed between the light source and the adjacent end of the harness where it enters the box, the colour filters being moveable into and out of the light path.

The tape may be provided with reference slots at spaced intervals to provide a signal to the aspect/datum sensor to show the precise position of the tape. The tape may also have coded slots at intervals to provide signals to the sensor indicating the number, letter or other sign which will be displayed on the sign face.

Preferably the aspect punched holes in the tape are elongated in the longitudinal direction of the tape, and the positioning punched holes are elongated in the vertical plane.

The motors which drive the tape are preferably arranged so that one motor drives in one direction while the other motor free-wheels and vice versa.

In the accompanying drawings: Figure 1 is a schematic representation of one display or sign face incorporating the present invention; Figure 2 is a plan view of the tape shown in Figure 1; Figure 3 is an end elevation of the tape and illustrates how the ends of the optical fibres are incorporated in blocks; Figure 4 is an elevation of one light box; and Figure 5 is a section on line A--A shown in Figure 4.

Figure 1 shows a sign face 10 incorporating a matrix of 35 light points or pixels 11 some of which are shown illuminated to form a letter A.

Light is provided from a light box 12 provided with two light sources, such as halogen light bulbs 13 and 14, two light input harnesses of optical fibres 15 and 16, or asplit harness, are shown with their ends 17 and 18 entering the box 12 on two sides of the box. The other ends of the optical fibres in each harness are supported in a block 19. An output harness of optical fibres 20 conveys light from a second block 21 to the sign face 10. Each pixel 11 may have one or multiple individual optical fibres feeding into it. What is displayed on the sign face 10 is determined by a coded tape 22 which is arranged to run between the blocks 19 and 21 and is carried by tape spools 23 and 24 driven by motors 25 and 26.

Motor 25 drives in the direction of arrow 27 whilst motor 26 freewheels. Similarly, motor 26 drives in the direction of arrow 28 whilst motor 25 free-wheels.

The display face is controlled by an electronic controller 29 which controls the motors 25 and 26 and also switches on and off the lights 13 and 14. The electronic controller is fed with signals from an aspect or datum sensor 30 which picks up reference slots 31 and 32 (Fig. 2) on the tape 22. This enables the precise position of the tape to be determined to ensure that slots 33 in the tape 22, which determine what is displayed on the sign face, are correctly positioned.

A further coded set of slots 34 is used to provide a signal through the aspect/datum sensor to the electronic controller 29 to show the particular symbol etc. which is being displayed.

Figure 3 shows in more detail how the harnesses are fed into the fibre blocks and the coded tape lies in the narrow space between the blocks in order to ensure that light coming through the blocks is not lost due to spreading of the beams. The space between the blocks is kept to the minimum possible. For instance, this space may be as little as 0.8mm and the tape may be 0.5mm.

Figure 4 shows in more detail one of the light boxes 12. The splitter mirror 35 is set at a 45-degree angle in the box; light from the halogen light bulbs 13 and 14 is split. For instance, the light from bulb 13 will go directly across to the harness end 15A but a proportion of the light will be reflected by splitter mirror 35 so as to be directed to the harness end 20A. Similarly, light from halogen bulb 14 will be split, part of it going to harness end 28 directly and part of it being reflected to harness end 15A. This ensures that if one light bulb should fail, light will still go to each harness end from the other halogen bulb. In the light box 12 there are two colour filter assemblies 36 and 37 which can be seen more clearly in Figure 5. Filter assembly 36 carries a green filter 38 and filter assembly 37 carries a red filter 39.The filter assemblies are operable by solenoids so as to place either a green filter or a red filter between the adjacent harness end and the splitter mirror. If colour is not required, they can both be withdrawn.

The electronic controller 29 is provided with a keyboard to enable the user to select the desired symbol, letter or figure. When the displayed symbol is to be changed, the operator presses the appropriate key. This immediately turns the light bulbs off and operates the appropriate one of the spool drive motors to move the tape to a new position. When the desired position is reached, the reference slots shown in Figure 2 will provide a signal via a photoelectric cell (not shown) to the electronic controller which will ensure that the tape is positioned accurately to enable the desired symbol to be displayed. Once the desired symbol position is reached, the tape stops and the light is automatically turned on again.

Slots 33 in the tape are elongated to accommodate tape wear and to avoid the necessity of overly precise positioning.

As mentioned above, the light coming from the fibre ends within block 19 will tend to spread slightly as it crosses the gap. To accommodate this, the fibres in harness 20 may be of greater diameter than the fibres in harnesses 15 and 16 and the holes in the block 21 may be correspondingly enlarged compared with the holes in block 19. The use of a larger diameter fibre in harness 20 enables the whole of the light to be picked up despite any spreading which occurs in the gap. Glass fibres are used in harnesses 15 and 16 and may be used in harness 20, but if a larger fibre is used in accordance with this modification, then plastic optical fibres are preferably used.

In a preferred design, there will be a row or multiple rows each containing a given number of character units, the whole being controlled via a computer or interface from a control centre to display any alpha numeric messages or pre-programmed pictograms or both.

Claims

1. A display or sign face comprising a matrix of points, or pixels which may be selectively illuminated to display a selected letter, number or other symbol or pattern, light being supplied from a light source through a harness of input optical fibres, the free ends of which are supported in a block, a second harness of output optical fibres being provided to convey light from a second block to the matrix of points or pixels on the display or sign face, the first and second blocks lying closely adjacent each other and a coded punched tape being located in a gap between the two blocks, the punched tape incorporating a series of groups of punched holes which allow light from selected input fibres to enter selected output fibres so as to display a particular letter, number or other symbol or pattern.

2. A display or sign face according to Claim 1 and in which the tape is carried on motor-driven spools and its position is determined by an electronic controller which receives signals from an aspect or datum sensor to indicate the position of the tape.

3. A display or sign face according to Claim 1 or Claim 2 and in which the controller includes means to switch the light source off during movement of the tape and to switch it on when a selected point on the tape is reached.

4. A display or sign face according to any preceding Claim and in which the electronic controller includes means to operate one or more drive motors to move the tape.

5. A display or sign face according to any preceding Claim and in which the light source is in the form of a light box with fibre harnesses connected to two sides of the box and two sources of light located in the other two sides of the box, the light being directed through a splitter so that each harness receives part of the light directly from one light source and a second part of the light indirectly from the other light source.

6. A display or sign face according to Claim 5 and in which there are a number of light boxes, or a single light box, and the light box or boxes are provided with two sets of colour filters which may be interposed between the light source and the adjacent end of the harness where it enters the box, the colour filters being moveable into and out of the light path.

7. A display or sign face according to any preceding Claim and in which tape is provided with reference slots at spaced intervals to provide a signal to the aspect/datum sensor to show the precise position of the tape.

8. A display or sign face according to any preceding Claim in which the tape has coded slots at intervals to provide signals to the sensor indicating the number, letter or other sign which will be displayed on the sign face.

9. A display or sign face according to any preceding Claim and in which the aspect punched holes in the tape are elongated in the longitudinal direction of the tape, and the positioning holes are elongated in the vertical plane.

10. A display or sign face according to any preceding Claim and in which the motors which drive the tape are arranged so that one motor drives in one direction while the other motor free-wheels and vice versa.

11. A display or sign face according to any preceding Claim and in which the optical fibres in the second harness are of greater diameter than the optical fibres in the first harness to accommodate spreading of light.

12. A display or sign face according to any preceding Claim and in which the gap is no greater than 0.8mm and the tape is no thicker than 0.5mm.

13. A display or sign face substantially as hereinbefore particularly described and as illustrated in the accompanying drawings.