GB1599298A - Indirect viewing systems eg for use in vehicles aircraft vessels or security systems - Google Patents

Description

(54) INDIRECT VIEWING SYSTEMS EG: FOR USE IN VEHICLES, AIRCRAFT, VESSELS OR SECURITY SYSTEMS (71) We, EMMANUEL ENTER PRISES LIMITED, a British Company, of 59 Mayflower Way, Farnham Common, Buckinghamshire, SL2 3US, do hereby declare the invention, for which we pray that a patent may be granted to us, and the method by which it is to be performed, to be particularly described in and by the following statement: This invention relates to an indirect viewing apparatus and particularly to a vehicle rear-view mirror.

In vehicles for example it is difficult to achieve a panoramic view from externally placed mirrors because of the necessity to place the mirrors at one side or other of the vehicle. One proposal to increase the rearview in a vehicle is the provision of mirrors of the convex type which reduce the size of the image but cover a wider field of vision: however this still suffers from the basic disadvantage of location.

A proposal to overcome this was put forward in British Patent Specification No.

1,103,213 which disclosed apparatus for observing the rear of a vehicle by using fibre optics. The latter proposal, although overcoming the necessity to locate the mirrors at one side of a vehicle is still not a particularly satisfactory arrangement because of the construction of the receiver which receives the initial image.

According to the present invention there is provided an indirect viewing apparatus comprising an image receiver, a display, and fibre optic means for transmitting an image from the receiver to the display for viewing by a user, the image receiver including a flexible reflective surface disposed between two supporting surfaces one of which is transparent, a sealed chamber being formed between the reflective surface and each supporting surface and one of the chambers having means for introducing pressure or vacuum so that the optical properties of the apparatus may be varied.

Preferably the flexible membrane moulds itself substantially completely to a supporting surface in each of its extreme positions.

The invention will now be described by way of example with reference to the accompanying drawings in which: Figure 1 is a side elevation of a vehicle incorporating an indirect viewing apparatus in accordance with the invention; Figure 2 illustrates diagrammatically an optical fibre transmission for the apparatus of Figure 1; Figure 3 illustrates a side elevation of a vehicle incorporating a modification to the arrangement shown in Figure 1; Figure 4 illustrates diagrammatically an optical fibre transmission for the apparatus of Figure 3; Figure 5 is a preferred form of image receiver in a first mode; Figure 6 is the image receiver of Figure 5 in an alternative mode; Figure 7 is a perspective view of an alternative form of image receiver; and Figure 8 is a section on X-X of Figure 7.

In Figures 1 and 2 of the drawings a vehicle 1 has an indirect viewing apparatus comprising an image receiver 2 mounted on the back 2A of the vehicle 1 at a generally central position and a display screen 3 in the vehicle dashborad 4 where it can be seen by the driver. The image receiver 2 is connected to the display screen 3 by means of a bundle of optical fibres 5, shown in Figure 2, which takes any convenient path from the rear of the vehicle e.g. as shown in dotted lines.

In Figures 3 and 4 a similar arrangement is shown except that in addition to the central image receiver 2 there are provided two 3/4 side receivers 6. Thus, in this embodiment the bundle of optical fibres 5 is trifurcated to provide side branches 7 to the side receivers 6.

The preferred form of image receiver is shown in Figures 5 and 6 and consists of a housing 10 into which the bundle of optical fibres 5 extend. The housing 10 includes a mirror in the form of a reflective flexible membrane 11 which is mounted between two suitably shaped supporting surfaces 12 and 13 each of which, with the flexible membrane 11, form a chamber 14 of variable size. The chambers 14 are pneumatically sealed and have pipe connections 15 to a pneumatic control system (not shown) so that by introducing pressure or vacuum to one or other chamber 14 the optical properties of the system can be varied by the driver. The front supporting surface 12 is transparent and as shown the flexible membrane 11 moulds itself to one or other supporting surface 12 or 13 depending upon which chamber 14 has been pressurised. The flexible membrane 11 therefore is substantially unstressed in each of its extreme positions shown in the Figures and one or other chamber 14 in the extreme positions is completely voided. The reflective flexible membrane 11 may be Melinex (trade mark) for example.

The embodiment shown in Figures 7 and 8 is a combined panoramic and corner viewing arrangement in which the flexible membrane is movable between two suitably shaped supporting surfaces 16 and 17.

In both the embodiments of image receiver the effect of refraction has been ignored and the spacing between the supporting surfaces has been increased for clarity.

An advantage of the present invention is that it overcomes the geometric difficulties inherent in conventional rear-view mirrors by producing an internal display from an optical system suitably located at the rear of the vehicle or some other convenient place.

The proposed system also eliminates the difficulty of viewing an external mirror, which itself may be obscured by moisture and dirt, through a side window or front screen similarly obscured.

Preferably the display screen 3 is mounted in the vicinity of the dash-board 4 but it may be mounted adjacent a normal internal rear-view mirror if desired.

In view of the properties of optical fibres the rear-view system may be mounted so as to be rotatable to facilitate reversing and parking without adversely affecting the picture displayed on screen 3. The movement may be controlled by means of a switch in a suitable electrical circuit or lever controlled by the driver of the vehicle.

As the image receiver is mounted externally of the vehicle the optical system will pick up dirt during use. Therefore it is preferable that a water and/or air jet system is incorporated to keep the external face of the system free from dirt and moisture. Hot air or heating elements may also be introduced to defrost the surface during winter.

The apparatus of the invention allows the view seen by the driver on the display screen 3 to be varied as desired by controlling the pneumatic fluid passing to the chambers 14.

If a magnified picture is required on the display screen 3 a suitable magnifying lens may be provided between the bundle of optical fibres 5 and the screen 3.

The supporting surface between which the reflective flexible membrane is mounted may be of any suitable shape and according to their shape may allow changes of beam direction or close or distant viewing.

Although the apparatus of the invention is primarily concerned with vehicle rear view systems i.e. for cars, lorries, coaches etc. it is understood that the apparatus is equally applicable to all kinds of uses where an indirect viewing system is required. For example the apparatus of the invention may be used in any of the following other applications: (a) in a vehicle for forward viewing during fog conditions; (b) in an aircraft for checking the undercarriage during landing or to give the captain a view of the cabin as an anti-hijack system; (c) in a vehicle for night-time viewing for facilitating parking or reversing. The system may be connected to the reversing light circuit or may have a combined light source which illuminates the viewing being picked up by the receiver; (d) in marine or submarine vessels, e.g.

for monitoring propellor or the like; or (e) in a security system.

It is also understood that the basic system may include more information for the user whilst not departing from the scope of the invention. For example a rear view system could include a central receiver having a panoramic rear-view and two corner mounted 3/4 rear view receiver units each permanently displaying a separate view onto a three-sectional display screen or a single display including a selective switch to obscure those views not required.

WHAT WE CLAIM IS: 1. An indirect viewing apparatus comprising an image receiver, a display, a fibre optic means for transmitting an image from the receiver to the display for viewing by a user, the image receiver including a flexible reflective surface disposed between two supporting surfaces one of which is transparent, a sealed chamber being formed between the reflective surface and each supporting surface and one of the chambers having means for introducing pressure or vacuum so that the optical properties of the apparatus may be varied.

2. An indirect viewing apparatus

**WARNING** end of DESC field may overlap start of CLMS **.

Claims (6)

**WARNING** start of CLMS field may overlap end of DESC **. The preferred form of image receiver is shown in Figures 5 and 6 and consists of a housing 10 into which the bundle of optical fibres 5 extend. The housing 10 includes a mirror in the form of a reflective flexible membrane 11 which is mounted between two suitably shaped supporting surfaces 12 and 13 each of which, with the flexible membrane 11, form a chamber 14 of variable size. The chambers 14 are pneumatically sealed and have pipe connections 15 to a pneumatic control system (not shown) so that by introducing pressure or vacuum to one or other chamber 14 the optical properties of the system can be varied by the driver. The front supporting surface 12 is transparent and as shown the flexible membrane 11 moulds itself to one or other supporting surface 12 or 13 depending upon which chamber 14 has been pressurised. The flexible membrane 11 therefore is substantially unstressed in each of its extreme positions shown in the Figures and one or other chamber 14 in the extreme positions is completely voided. The reflective flexible membrane 11 may be Melinex (trade mark) for example. The embodiment shown in Figures 7 and 8 is a combined panoramic and corner viewing arrangement in which the flexible membrane is movable between two suitably shaped supporting surfaces 16 and 17. In both the embodiments of image receiver the effect of refraction has been ignored and the spacing between the supporting surfaces has been increased for clarity. An advantage of the present invention is that it overcomes the geometric difficulties inherent in conventional rear-view mirrors by producing an internal display from an optical system suitably located at the rear of the vehicle or some other convenient place. The proposed system also eliminates the difficulty of viewing an external mirror, which itself may be obscured by moisture and dirt, through a side window or front screen similarly obscured. Preferably the display screen 3 is mounted in the vicinity of the dash-board 4 but it may be mounted adjacent a normal internal rear-view mirror if desired. In view of the properties of optical fibres the rear-view system may be mounted so as to be rotatable to facilitate reversing and parking without adversely affecting the picture displayed on screen 3. The movement may be controlled by means of a switch in a suitable electrical circuit or lever controlled by the driver of the vehicle. As the image receiver is mounted externally of the vehicle the optical system will pick up dirt during use. Therefore it is preferable that a water and/or air jet system is incorporated to keep the external face of the system free from dirt and moisture. Hot air or heating elements may also be introduced to defrost the surface during winter. The apparatus of the invention allows the view seen by the driver on the display screen 3 to be varied as desired by controlling the pneumatic fluid passing to the chambers 14. If a magnified picture is required on the display screen 3 a suitable magnifying lens may be provided between the bundle of optical fibres 5 and the screen 3. The supporting surface between which the reflective flexible membrane is mounted may be of any suitable shape and according to their shape may allow changes of beam direction or close or distant viewing. Although the apparatus of the invention is primarily concerned with vehicle rear view systems i.e. for cars, lorries, coaches etc. it is understood that the apparatus is equally applicable to all kinds of uses where an indirect viewing system is required. For example the apparatus of the invention may be used in any of the following other applications: (a) in a vehicle for forward viewing during fog conditions; (b) in an aircraft for checking the undercarriage during landing or to give the captain a view of the cabin as an anti-hijack system; (c) in a vehicle for night-time viewing for facilitating parking or reversing. The system may be connected to the reversing light circuit or may have a combined light source which illuminates the viewing being picked up by the receiver; (d) in marine or submarine vessels, e.g. for monitoring propellor or the like; or (e) in a security system. It is also understood that the basic system may include more information for the user whilst not departing from the scope of the invention. For example a rear view system could include a central receiver having a panoramic rear-view and two corner mounted 3/4 rear view receiver units each permanently displaying a separate view onto a three-sectional display screen or a single display including a selective switch to obscure those views not required. WHAT WE CLAIM IS:

1. An indirect viewing apparatus comprising an image receiver, a display, a fibre optic means for transmitting an image from the receiver to the display for viewing by a user, the image receiver including a flexible reflective surface disposed between two supporting surfaces one of which is transparent, a sealed chamber being formed between the reflective surface and each supporting surface and one of the chambers having means for introducing pressure or vacuum so that the optical properties of the apparatus may be varied.

2. An indirect viewing apparatus

according to claim 1 wherein the flexible membrane moulds itself substantially completely to a supporting surface in each of tis extreme positions.

3. An indirect viewing apparatus according to claim 1 or 2 wherein the image receiver is mounted on the exterior of a vehicle and the display is mounted within the vehicle for viewing by the vehicle driver.

4. An indirect viewing apparatus according to claim 3 wherein the image receiver is centrally mounted at the rear of the vehicle.

5. An indirect viewing apparatus according to claim 3 or 4 including additional image receivers one mounted at each rear corner of the vehicle.

6. An indirect viewing apparatus substantially as hereinbefore described with reference to and as illustrated in the accompanying drawings.