WO2001042738A1

WO2001042738A1 - Ranging system

Info

Publication number: WO2001042738A1
Application number: PCT/GB2000/004684
Authority: WO
Inventors: Anthony Peter Williams
Original assignee: Anthony Peter Williams
Priority date: 1999-12-07
Filing date: 2000-12-07
Publication date: 2001-06-14
Also published as: GB2375831B; GB0215629D0; GB2375831A; AU2190301A

Abstract

A ranging and/or alignment system comprises two points that, in use, are different distances from, for example, a user's eye (50). Rotation of the apparatus (3) away from correct alignment gives the user a visual warning of non-alignment (Figure 2(b)).

Description

RANGING SYSTEM

The present invention is concerned with optical alignment or ranging for alignment with, or ranging from, a light-sensing member. The invention has particular, but not exclusive, application to alignment or ranging of a human eye when a person is capturing-him or herself with a still or video camera. A new era of personal communications is imminent in which the traditional mobile telephone is further equipped to provide a picture of a first user to the second user, which second user may be using another mobile telephone or fixed-line device.

There is extensive current interest in mounting capacitive charge coupled device cameras onto a mobile communications apparatus. These camera devices offer good resolution, low current consumption and small size. However, a problem arises when the camera is used. Unless the person using the camera has a particularly good spatial sense, it is extremely unlikely that the camera will be both correctly aligned and correctly distanced from the user's face. The person at the other end of the communications link is just as likely to receive a picture of the user's jacket or a wall as their face.

A proposed solution to this problem is to provide a "picture-in-picture" feature whereby part of the screen is used to give the user a picture of their own face. However, there are a number of disadvantages with this approach. Firstly, it is a costly arrangement because small LCD screens are expensive and it also makes demands of processor time. Secondly, if the user's face cannot be seen, he or she cannot tell which way to turn the device. Thirdly, the processing rates available mean that there will only be a few frames per second. The user may see his or her image but, in fact, the camera is pointing the wrong way.

It is an object of the present invention to provide apparatus for ameliorating the above problem. According to a first aspect of the invention, there is provided apparatus to provide ranging from, or alignment with, a light-sensing member, the apparatus comprising: a first layer comprising at least a first zone and a second zone, the second zone being optically distinguishable from the first zone; a second layer, spaced from the first layer, comprising a third zone and a fourth zone, the fourth zone being optically distinguishable from the third zone and which fourth zone is at least partially transparent, wherein the second zone is detectable, at least in part, by a light level detected by the light-sensing member via the fourth zone when the range or alignment of the apparatus is substantially correct.

The alignment apparatus provides a simple arrangement in which the relative angular orientation (in one or two dimensions) and/or the range of the apparatus can readily be determined by a light-sensing member. While in the following examples the light- sensing member is a human eye, the present invention is equally applicable to an electronic light-sensing member.

A number of arrangements of the shape of the optically-distinguishable zones are possible. A triangular shape is presently preferred but other shapes are possible. For example, a rectangle may be the most appropriate shape to use in a mobile communications apparatus because it may be arranged around a liquid crystal display. In addition to a triangular or other shape, the arrangement may further be provided with some small areas offering higher precision. One example of such an area would be a small circle or dot. When the alignment is poor it would not be clear from such a small optically-distinguishable zone in which direction the alignment apparatus and the light- sensing member should be rearranged. However, the apparatus is also provided with some linear members, for example in the shape of a triangle, which provide a coarse adjustment. Once the coarse adjustment is satisfied, some further adjustment may be effected to properly align the small optically-distinguishable zones. J

By adjustment of the relative spacing of the first and second layers together with the size and shape of the optically-distinguishable zones, the apparatus according to the present invention can readily be adapted to provide almost any degree of required precision.

The optically-distinguishable zones located on the first layer may comprise, for example, a black zone together with reflective zones, different coloured zones or holographic material. The apparatus may be lit from beneath the first layer, from the side of the first layer or via the second layer using either an in-built light source or ambient light.

According to a second aspect of the present invention, there is provided apparatus for alignment with and/or ranging from a light sensing member which member is located at a distance from the apparatus, the apparatus having a finite thickness, one part of the apparatus is closer in use to the light sensing member and another part of the apparatus is further in use from the light sensing member; wherein the one part and the another part co-operate optically to indicate the alignment and/or ranging to the light sensing member.

According to a third aspect of the present invention, there is provided a mobile communications apparatus comprising a screen, a camera and apparatus for alignment with and/or ranging from a light sensing member which member is located at a distance from the apparatus, the apparatus having a finite thickness, one part of the apparatus is closer in use to the light sensing member and another part of the apparatus is further in use from the light sensing member; wherein the one part and the another part co-operate optically to indicate the alignment and/or ranging to the light sensing member.

According to a fourth aspect of the present invention, there is provided a mobile communications apparatus comprising a screen, a camera and apparatus to provide ranging from, or alignment with, a light-sensing member, the apparatus comprising: a first layer comprising at least a first zone and a second zone, the second zone being optically distinguishable from the first zone: a second layer, spaced from the first layer, comprising a third zone and a fourth zone, the fourth zone being optically distinguishable from the third zone and which fourth zone is at least partially transparent, wherein the second zone is detectable, at least in part, by a light level detected by the light-sensing member via the fourth zone when the range or alignment of the apparatus is substantially correct.

The present invention will now be described, by way of example, with reference to the accompanying drawings in which:

Figure 1 illustrates some suitable arrangements of optically-distinguishable zones as used in embodiments of the present invention;

Figure 2 illustrates a first principle of the invention which provides accurate orientation of an apparatus relative to a light-sensing member;

Figure 3 illustrates a second principle of the invention in which the range of an apparatus and a light-sensing member is adjusted;

Figure 4 shows a mobile communications apparatus in accordance with an aspect of the present invention fitted with an optical alignment apparatus in accordance with another aspect of the invention;

Figure 5 shows a ranging system in accordance with an embodiment of the present invention for use with a Web TV arrangement;

Figure 6 shows two possible back-lighting arrangements for the apparatus in accordance with the present invention;

Figure 7 shows an arrangement for warning drivers of motor vehicles that they are travelling too closely to the vehicle in front;

Figures 8(a) and (b) show alternative arrangements of optically distinguishable zones; Figure 9 shows a side view in section of another embodiment of the invention;

Figures 10(a) to (d) illustrate a watch in accordance with an embodiment of the present invention

Figures 11 to 13 illustrate the theory of operation of an embodiment of the present invention; and

Figures 14 and 15 show another application of an embodiment of the invention to vehicle safety.

Figure 1(a) shows a plan view of a first example of optically-distinguishable zones. In this case, a first zone is in the shape of a cross, while a second zone surrounds that cross. As will be explained with reference to Figure 2 below, this allows adjustment of relative orientation in two orthogonal dimensions.

Figure 1 (b) shows an alternative arrangement of a first optically-distinguishable zone in which three linear portions 10, 12, 14 are arranged along each side of an equilateral triangle. The portions 10, 12, 14 do not occupy the whole of the side of the triangle. At each corner of the triangle is located a small circular portion or dot 16, 18, 20 which is used to provide extra precision, as will be discussed below.

The arrangement of optically-distinguishable zones as shown in Figures 1(a) and (b) are used to provide optically-distinguishable zones in both a first layer and a second layer of a device. The first layer and the second layer are spaced apart. This is illustrated in more detail with reference to Figure 2(a).

Figure 2(a) shows a side view of an arrangement in accordance with an embodiment of the invention. The side view of the apparatus corresponds with that shown in line II-II of Figure 1(a). A first layer 30 comprises a dark zone 32 and a reflective zone 34. A second layer 40 comprises a dark zone 42 and a transparent zone 44. The second layer is spaced from the first layer by a finite distance d. A user's eye 50 is shown located above the arrangement. Lines of light entering the eye 50 are shown in broken lines.

In Figure 2(a) the alignment between the user's eye 50 and the apparatus is perfect (in the plane illustrated). The reflective zone 34 of the first layer is directly below the transparent zone 44 of the second layer. The user 50 will therefore see a strong reflection from the reflective zone 34 through the transparent zone 44 and will not see any of the darkened zone 32 of the first layer 30.

Figure 2(b), however, shows a different situation. In this case the apparatus lies at a different angle from that shown in Figure 2(a). From the perspective of the user's eye, therefore, the appearance of the reflective zone 34 has changed. As can be seen from the lines of sight shown in Figure 2(b), the user will now observe a somewhat smaller amount of reflected light from the reflective zone 34. The user can also see a portion of the dark zone of the first layer 30. It will be apparent to the user that the orientation between his eye and the apparatus is not correct. Because the user can see a darkened zone 32 on the right side (as shown in the figure) of the reflective zone 34, it is clear that the apparatus needs to be rotated in direction r to obtain proper alignment.

Because of the relative size and spacing of the reflective zone 34 and the transparent zone 44, it is possible to orient the device relative to a user's eye so that the reflective zone 34 is not visible at all. In the case shown in Figure 2(c) the user will only observe a part of the darkened zone 32 of the first layer. However, in this case it will be readily apparent that the device needs to be rotated in the direction r because the user's vision will perceive only an oblique view of the device.

Figure 2 has shown how the apparatus operates to provide proper orientation or alignment in one direction. The process is repeated in another direction orthogonal to the first and also orthogonal to the line of sight. Figures 11, 12 and 13 illustrate the theory behind the alignment aspect of the invention. Figure 11 shows a simplified side view of the device 400 having two layers and light source 407. From the space 406 the light source is totally visible. Between this space and the lines 402 and 404 the light source 407 is partially visible. A user's eye is shown at a cross 408 at a distance d from the device and a distance y from the space 406. The equation giving the proportion of the light source 407 visible from any point between the space 406 and the lines 402, 404 is:

For lines: Proportion of maximum light visible fro cross 408 -

For circles: Proportion of maximum light visible from cross 408 =

Figure 12 shows an example of the device shown in Figure 1(b) with some dimensions Figure 12 is a diagram of the layout of slots on the plate. The arrangement is along the sides of an equilateral triangle of side 13.5 mm. Two identical plates are mounted 10mm apart. The characteristics obtained are shown in figure 13.. Figure 13 shows a graph of amount of light source visible against lateral displacement for both the slots and the circles in the device. The circle is visible at a greater displacement due to its greater width.

Figure 3 illustrates an alternative embodiment which allows the present invention to provide ranging.

In this figure a ranging apparatus 51 comprises a first layer 52 having a first zone 54 and second zones 56. A second layer 58 comprises a third zone 60 and fourth zones 62. A human eye 50 is shown arranged at the correct distance or range from the apparatus. Such a correct distance may be determined from the focal length of a camera or the desired field of view (where the camera does not have a critical focal length). The arrangement can also be used to provide a minimum distance warning as will be described below with reference to Figure 7.

Considering Figure 3(a), the principle is similar to that described with reference to Figure 2, namely that a second zone 56 of the first layer 52 is visible via a transparent zone 62 of a second layer 58. The two layers are spaced by a distance d as before. Where the apparatus is arranged at the correct distance from the light-sensing member (eye 50) the zones 56 are completely visible via the transparent zones 62 in the second layer.

Figure 3(b) shows the apparatus arranged too close to the light-sensing member 50. In this case, the zones 56 on the first layer are not fully visible via the transparent zones 62 on the second layer. The first zone 54 of the first layer is visible on the outside of the second zone 56. From this, the user can determine that the apparatus is too close to his eye.

In contrast, Figure 3(c) shows a case where the optical-sensing member 50 is arranged too far from the alignment apparatus. In this case the second zones 56 in the first layer are also completely visible via the transparent zones 62 in the second layer. However, in this case the portion of the first zone 54 which is visible via the transparent zones 62 is on the inside of the zones 56. Consequently, a user (or machine as appropriate) can determine that the ranging apparatus is too distant from the light-sensing member.

It is possible to arrange an embodiment of the present invention to provide ranging control without orientation control. One such arrangement would comprise a plurality of optically distinguishable zones (for example the triangle arrangement shown in Figure 1(b)) arranged on the surface of a sphere (or part thereof). Proper visibility of one of the triangles indicates correct ranging.

In a preferred embodiment, the apparatus is arranged to provide both ranging and alignment (orientation) with respect to a light-sensing member. The arrangement of zones shown in Figure 1 (b) is particularly suited to this.

The invention is applicable to the field of people recognition via optical biometrics. Iris recognition is a well known example but the filed also includes retinal recognition and facial recognition for example. These techniques usually require quite precise positioning of the user's face or eye relative to the apparatus. The arrangement described here can readily be adapted (using the formula in Figure 1 1 , for example) to give the required degree of precision. The user then simply aligns his or her eye with the ranging and alignment device while the relevant features are scanned and compared as appropriate.

The invention has application to greater ranges than can be discerned by unaided human eyesight. Using a laser, for example, the invention may be applied to range and orientation control over vast distances (dependent on the power of the laser). One possible application is as a back-up system for spacecraft guidance in near-Earth orbit.

The invention is also applicable over shorter distances - for example to align machinery or dock vehicles. The arrangement could be used as a back-up device to arrange a precise approach path for docking space vehicles. A number of the devices could be used in such a situation. Devices arranged to operate at closer range would only become detectable ("visible") at close proximity. This would provide better resolution at short distances and could also provide a warning that the two vehicles were very close.

Figure 4 shows a plan view of a mobile communications apparatus equipped with a ranging or alignment apparatus in accordance with the first aspect of the present invention. In addition to the ranging or alignment apparatus (which is basically as shown in Figure 1 (b)) the apparatus is provided with a camera 80 substantially at the centre of the fourth zones of the second layer. This is preferably a capacitive charge- coupled-device (CCD) camera. These cameras do not have an especially critical focal length. However, the range of a user from the camera is important to ensure that the user's face substantially fills the frame which is being imaged. To this end, the triangular pattern of the fourth zone in the second layer is repeated as the second zone on the first layer at a slightly greater spacing. By referring to Figure 3 (especially Figure 3(a)) it will be appreciated that this increased spacing can be adjusted to provide the ideal frame size for an averagely-sized user's face. Use of the present invention is not limited to portable apparatus and the problem of correct alignment and frame sizing also occurs in the use of static telephonic apparatus and computer apparatus (such as a video conferencing system).

Figure 5 shows a camera 80 arranged in a separate device arranged on top of a PC monitor. The principle of operation is the same as that shown in Figure 4, i.e. to ensure that the person or persons at the other end of the communication link have a reasonable picture of the user sitting in front of the camera. The camera unit may be arranged so as to be adjustable, both from left to right and up and down, or the user may have to physically rearrange themselves in front of the unit to ensure a good picture.

The patterns described thus far may be replaced by a hologram in another embodiment. A hologram may work better in conditions of poor light because the hologram naturally diffuses light well. A solution to the problem of low ambient light will now be described.

The description so far has assumed that there is sufficient ambient light to operate the invention, in other words that the second zone of the first layer is clearly visible via the transparent zones in the second layer. However, this will not always be the case.

One solution to this problem would be to reverse the transparent and other zones of the second layer so that the larger of the two zones in the second layer would be transparent. In this case, therefore, seeing any of the second zone of the first layer would be undesirable. The user would adjust the relative orientation to minimise or eliminate any view of the second zone.

An alternative solution, is to provide a backlight. Two possible arrangements are shown in Figure 6 where a small, but preferably high intensity light emitting diode (LED) 90 is arranged at one side of the arrangement between the first and second layers. Clearly, an alternative light source, such as an incandescent lamp or electroluminescent lamp could be used. Alternatively, the backlight 100 may be provided beneath the first layer rather than to the side. Where the backlight is provided beneath the first layer, it will be important to choose the light transmissivity of the first and second zones of the first layer appropriately. Where the apparatus is arranged around a liquid crystal display, for example in a mobile telecommunicator, it is possible to arrange the apparatus to share the backlight with that display.

In a further embodiment the apparatus is provided on top of a liquid crystal display (LCD). The first and second layers of the arrangement would be provided, for example, with a substantially black area surrounding a small visible portion which coincided with the visible portions of the LCD. The LCD would then only be visible to the user when the arrangement was correctly oriented. Range setting can, as before, be determined by adjusting the relative sizes of the transparent portions on the first and second layers together with appropriate spacing of those layers. This can be achieved by screen printing the triangle on the top and bottom of the plastic display screen - the triangles in this case would be clear with a black surround on each. By adjusting the distance or thickness of the screen at this point - lining up the two - (with the light shining from the screen) - would be similar to lining up gun sights. The backlight displaying triangular shape would only work properly when the alignment is correct.

Figure 8(a) shows a series of concentric circles that may be used as the alignment pattern. The two layers of the pattern are arranged as shown in Figures 2 and 3 so that a lower layer of circles is fully visible when alignment and/or range is correct. As the user starts to look off-axis he is confronted by Moire patterns and intuitively knows which way to move relative to the apparatus to re-align.

Figure 8(b) is similar except that the pattern is a series of equilateral triangles. The principle of operation is the same.

Figure 9 shows a variation on Figure 3. Instead of two layers spaced apart and each carrying two optically-distinguishable zones the same principle can be applied to a first layer 210 with holes and/or slots to a second layer 220. The layer 220 is preferably reflective and this will be visible to a user through holes/slots 212, 214. In a preferred embodiment layer 220 comprises holographic material. As before, the second layer only becomes visible at the correct alignment and/or range. The range is adjusted by altering the angle θ and the principle is the same as shown in Figure 3. The thickness of layer 210 corresponds with the separation of the layers in Figures 2 and 3. The layer 210 may comprise a laminate as appropriate. Layer 220 may be backlit as discussed above.

The invention may be applied to a set of holes without any slots and this is particularly appropriate for use with a wristwatch-style communicator as shown in Figure 10. The communicator 300 has a multi-function screen 310 for providing video calls, watch functions and other functions such as a diary and address book. The communicator is also provided with four holes 320, 330, 340 and 350 which, in cross section, are similar to the features 212. 214 shown in Figure 9.

In Figure 10(a) the communicator is correctly aligned and the bottom of all four holes are fully visible. Because of the splayed nature of the holes, as the communicator is moved off-axis, some of the holes become dark (i.e. bottom is invisible) before others. This intuitively tells the user which way to tilt for correction.

Figure 10(b) shows the communicator tilted to the left so hole 330 has become dark and holes 320, 340 are half-dark.

Figure 10(c) shows the watch being tilted back and Figure 10(d) shows it being tilted forwards with similar effects.

In all cases it is intuitive to the user which way to tilt the device to correct the orientation.

In the figure, the size of the holes has been exaggerated for clarity. These may be of 0.3mm to 0.4mm in diameter and, preferably, 0.25mm in diameter to save space. The depth of the holes is typically 3 or 4mm as a diameter: depth ratio of about 1 :10 works well. Figure 7 shows an embodiment of the present invention applied to road safety. Figure 7 shows a rear view of a motor vehicle, as would be seen from the following vehicle. The drawing has been divided in two. In the left-hand case, the following vehicle is too close and a triangular shape 110 in accordance with the invention is a red colour. In contrast, the right-hand portion of the figure shows a car from which there is sufficient distance. In this case the triangular apparatus 110 is green. The principle of operation can be understood by reference to Figures 3(a) and (b). The first zone 54 of the apparatus shown in Figure 3 is red, while the second zone 56 is green. Figure 3(a) now corresponds to a distance from the followed vehicle which is safe at the national speed limit. However, at a closer range (where the following vehicle does not have enough space to stop) the zone 54 of the first layer will become visible (see Figure 3(b)). In this embodiment the size of the zones 56 and 62 will have to be quite large to ensure that the red or green colours are visible to the driver of the following vehicle. The alignment between the driver and the triangular apparatuses 110 is important but, in practice, does not cause any difficulties. The reason being that, at motorway speeds, the angular variation between the line of sight of a driver in a low sports car and a driver in a large truck is rather small.

In this embodiment the relative spacing d of the first and second layer together with the relative locations of the zones 56 and 62 (Figure 3(a)) are adjusted to provide the desired distance for the maximum possible speed.

By way of refinement, a number of triangles can be provided on the rear of the vehicle. Each triangle is arranged to indicate a close following distance over a range of speed limits, for example 40-50 mph, 50-60 mph and 60-70 mph. In this arrangement, the individual units would not operate with ambient light but would be backlit according to the speed of the car. Further ranges may be added as desired. As a further refinement, the green portion of the device may be made invisible, i.e. black, so that the warning triangle only appears when the following vehicle is too close. An alternative arrangement is shown in Figures 14 and 15 with exemplary dimensions. The shape chosen here is triangular, which is the accepted road hazard symbol but it could be any shape or even lettering. It is fitted to the back of the vehicle so it can be visible from following vehicles. It could be part of the bumper, completely separate or incorporated into the rear light cluster.

1. The warning triangle only becomes illuminated when a vehicle is travelling over a pre-determined speed (e.g. 80 kph/50 mph). At speeds below the pre-determined speed the device is invisible.

2. Ranging - The warning triangle is only visible to vehicles following dangerously close. Where a vehicle is beyond the prescribed distance the driver will be unaware of the triangle whether it is illuminated or not.

3. Alignment - The device, when illuminated, is invisible to traffic in adjacent lanes so it is not annoying. See the discussion of Figure 15B below.

4. Multiple illuminating triangles could be arranged within each other providing a wide range of speed and separation possibilities.

Construction:

1. The device is triangular with transparent standard red plastic and illuminated from behind. The three slots, arranged in the shape of a triangle, have further fins located in them. Inclined fins 501 are provided on the sides and vertical fins 502 are provided on the bottom. A light source 503 is provided.

2. The light source 503 is turned on and off at the determined speed by means of an electronic circuit. Data for determining the speed may be derived from either:

a. A sensor connected to the vehicle's speedometer data or logic system. Or: b. A tiny propeller device driven by the vehicle's airspeed and generating electrical current which can be measured.

As an alternative the back light could be made to become progressively brighter with speed, using standard available electronics. Ranging (figure 15 A)

A dense 600 is used. The ranging is predetermined by the use of substantially horizontal slats angled and arranged such that the light is out of alignment and therefore not visible beyond the prescribed distance. Figure 15A is a plan view showing the triangular region 601 in which the triangle is visible. For example if the prescribed safety distance is 50 metres and the difference in height between the triangle and the typical driver's position is 1 metre, then the lowest angle of the visible light required would be a 1 in 50 slope. This would require an angle of drop from the horizontal of 1.14 degrees between the front visible edge of the lower slat to the rear lower edge of the next slat up. By adjusting this angle any set distance can be achieved. The fin means that the triangle is only visible from a position horizontally aligned with the device and in a plane slightly inclined from the horizontal.

The intention is that the device would be installed below the eye level of drivers and that the angling upwards of the viewing position will allow the ranging effect to work.

The horizontal bar of the triangle does not require horizontal slats as it can be angled by using the depth of the slot as above.

The two sides of the triangle will have arrays of horizontal slats, which would be angled and arrayed as described above.

Note: these near-horizontal slats are needed in order to provide ranging over great distances.

Alignment:(Figure 15B)

To avoid drivers in adjacent lanes becoming annoyed, alignment of the light from the sides of the triangle is pre-determined by the use of the 'angled slots as described previously. The angle of the slot is calculated in the same manner as above. The lower horizontal bar of the triangle is simply shielded by vertically arrayed fins. By slightly angling these fins inwards (as above) on each half of the bar additional ranging can be produced. Only vehicles following in the same lane will see the triangle but they will be too close given the speed of the vehicle they are following. If they are travelling slower than the vehicle in front, they will quickly drop out of range. The triangular region 602 in which the triangle is visible is shown. At a first point, 603 the driver can see the triangle because the driver is too close. At a second point 604, the driver cannot see the triangle.

Other benefits:

1. If it is assumed the higher the driver position the bigger and heavier the vehicle. Then bigger vehicles will be warned progressively further away. This is ideal, as heavier vehicles require a greater stopping distance. 2. As speed data is being used anyway, in instances of rapid deceleration then the triangle could be illuminated automatically as an extra warning device.

While the invention has been described and claimed, it should be understood that the disclosure extends to any teaching herein, whether explicit or implicit.

Claims

CLAIMS:

1. Apparatus to provide ranging from, or alignment with, a light-sensing member, the apparatus comprising: a first layer comprising at least a first zone and a second zone, the second zone being optically distinguishable from the first zone; a second layer, spaced from the first layer, comprising a third zone and a fourth zone, the fourth zone being optically distinguishable from the third zone and which fourth zone is at least partially transparent, wherein the second zone is detectable, at least in part, by a light level detected by the light-sensing member via the fourth zone when the range or alignment of the apparatus is substantially correct.

2. Apparatus as claimed in claim 1 , wherein the second zone has components in each of two orthogonal directions, which directions are both substantially perpendicular to an optical path between the apparatus and the light-sensing member.

3. Apparatus as claimed in claim 1 or claim 2, wherein the first layer comprises at least three zones.

4. Apparatus as claimed in claim 3, wherein the at least three zones on said first layer are identifiable by different colours.

5. Apparatus as claimed in claim 3, wherein the at least three zones on the first layer are arranged to provide different precision in ranging from, or alignment with, the light-sensing member.

6. Apparatus for alignment with and/or ranging from a light sensing member which member is located at a distance from the apparatus, the apparatus having a finite thickness, one part of the apparatus is closer in use to the light sensing member and another part of the apparatus is further in use from the light sensing member; wherein the one part and the another part co-operate optically to indicate the alignment and/or ranging to the light sensing member.

7. Apparatus as claimed in any one of claims 1 to 6, wherein the light-sensing member comprises a human eye.

8. Apparatus as claimed in any one of the claims 1 to 6, wherein the light-sensing member comprises light sensing apparatus.

9. Apparatus as claimed in any one of claims 1 to 8, further comprising a camera arranged so as to capture an acceptable image of a light-sensing member by way of ranging from, or alignment with, the light-sensing member.

10. Apparatus as claimed in claim 9, wherein the apparatus forms part of a personal computer-based television system.

11. Apparatus as claimed in any one of claims 1 to 10, further comprising a light source.

12. Apparatus as claimed in claim 11 , wherein the light source comprises a laser light source.

13. Apparatus as claimed in any one of the claims 1 to 12, wherein the apparatus includes a hologram.

14. Apparatus as claimed in any one of claims 1 to 13, wherein a screen is arranged in the third zone and the screen is substantially surrounded by the fourth zone.

15. Apparatus as claimed in any one of claims 1 to 13, wherein the fourth zone and second zone or the one part and the another part include dots.

16. Apparatus as claimed in any one of claims 1 to 15, wherein the fourth zone is substantially triangular.

17. Apparatus as claimed in any one of claims 1 to 16, further comprising further apparatus which operates at a different range.

18. Apparatus as claimed in any one of the claims 1 to 17, further comprising fins arranged to reduce angles of visibility of the device.

19. Apparatus as claimed in claim 18 wherein at least some of the fins are arranged at an angle.

20. Apparatus as claimed in claim 17, claim 18 or claim 19, wherein the apparatus is backlit and the backlighting is responsive to the speed at which the apparatus is travelling.

21. Apparatus as claimed in any one of claims 1 to 20, wherein the first and second layers are arranged on at least a portion of a sphere.

22. Apparatus as claimed in any one of the claims 1 to 21, further comprising apparatus for performing optical biometrics.

23. A mobile communications apparatus comprising a screen, a camera and apparatus for alignment with and/or ranging from a light sensing member which member is located at a distance from the apparatus, the apparatus having a finite thickness, one part of the apparatus is closer in use to the light sensing member and another part of the apparatus is further in use from the light sensing member; wherein the one part and the another part co-operate optically to indicate the alignment and/or ranging to the light sensing member.

24. A mobile communications apparatus comprising a screen, a camera and apparatus to provide ranging from, or alignment with, a light-sensing member, the apparatus comprising: a first layer comprising at least a first zone and a second zone, the second zone being optically distinguishable from the first zone; a second layer, spaced from the first layer, comprising a third zone and a fourth zone, the fourth zone being optically distinguishable from the third zone and which fourth zone is at least partially transparent, wherein the second zone is detectable, at least in part, by a light level detected by the light-sensing member via the fourth zone when the range or alignment of the apparatus is substantially correct.

25. An apparatus as claimed in claim 20 or claim 21, wherein the apparatus is wearable about the human body.

26. An apparatus as claimed in claim 22, wherein it is adapted to be worn about the wrist.