Optical device for indicating the glide angle of aircraft

Technical Field

This invention relates to an optical device for indicating the glide angle of aircraft.

In particular, this invention relates to an optical device which can project a light beam that forms a light path for guiding aircraft during landing, either on dry land or on marine platforms, whether fixed or floating.

Background Art

Known in the sector of aircraft guidance systems are light signalling devices designed to indicate a preset glide angle for helicopters and aeroplanes to allow them to correctly approach the surface of the landing ground or deck. In these applications, the light beam must be oriented both in elevation and in azimuth to identify the required landing path. In floating platform applications, for example on naval units, the beam must also be stabilized relative to the movements of the platform itself caused by sea wave motion. Stabilization is performed both relative to the angle of elevation, defined as the angle formed by an inclined plane with a horizontal plane and whose concavity is directed towards the landing light path, and relative to the angle of inclination, defined as the angle formed by an inclined plane with a horizontal plane and whose concavity is directed at right angles towards the landing light path.

Prior art devices feature a light source designed to produce a light beam which is transmitted to an image creating device.

The light image created is then projected through an optical lens and directed in the required direction through a reflecting element such as a suitably oriented mirror.

Some prior art devices use incandescent or halogen lamps, which have a limited life and whose luminous power diminishes rapidly over time. Moreover, devices of this kind use lamps that emit only white light, which must be subdivided into differently coloured sectors appearing side by side in a vertical plane in such a way as to identify different glide angles relative to a direction parallel to the landing ground or deck surface. This subdivision is obtained by interposing a filter between the light source and a light projector.

These devices, however, are veiy low in performance and thus the light produced is difficult for pilots to distinguish. Also, since there is a single light source, in order to obtain the frequency modulation of the lower and higher light sectors, it is necessaiy to provide mechanical partitions that screen the sectors with the required frequencies.

This leads to problems of alignment precision, cost of production, reliability and durability of mobile components.

In an attempt to overcome these problems, punctiform light sources have been used which consist of coloured LEDs, typically a red one, a green one and a blue/yellow one. according current regulations.

That makes it unnecessary to use further high-absorption filters for colouring the different sectors.

The use of these LEDs, however, requires the presence of a light ray transmission unit, such as fibre optic bundles which convey the three coloured light beams produced by the LEDs into a single image.

Despite the improvements brought about by the use of LEDs instead of incandescent lamps, it has been found that the light intensity of LEDs is weakened by the transmission unit. The Applicant has found that the structure of the device can be further simplified and reduced in overall dimensions.

The orientation and stabilization of the light beam in the above mentioned solutions, and in others in the prior art, are achieved by moving part of the device or the entire device. For example, the elevation of the beam is achieved by rotating a reflecting mirror. Stabilization in the horizontal, on the other hand, is typically achieved by turning the entire device, which, being relatively large and heavy, requires much more power than that required to move the reflecting mirror, as well as a more cumbersome and complex mechanism.

Disclosure of the Invention

In this context, the technical purpose which forms the basis of the present invention is to propose an optical device for indicating the glide angle of aircraft which overcomes the above mentioned disadvantages of the prior art. More specifically, this invention has for an aim to provide an optical device for indicating the glide angle of aircraft that is at once structurally simple and limited in size, especially as regards the light beam orientation unit.

Another aim of this invention is to provide an optical device for indicating the glide angle of aircraft that is low powered and efficient.

The technical purpose indicated and the aims specified are substantially achieved by an optical device for indicating the glide angle of aircraft comprising the technical features described in one or more of the appended claims. Brief description of the drawings

Further features and advantages of this invention are more apparent in the detailed description below, with reference to a preferred, non-limiting embodiment of an optical device for indicating the glide angle of aircraft, as illustrated in the accompanying drawings, in which:

Figure 1 is a schematic view of a ship equipped with an optical device for indicating the glide angle of aircraft according to this invention;

Figure 2 is a schematic representation of the optical device according to a basic embodiment;

Figure 2a is a schematic representation of the optical device according to a first variant of the configuration illustrated in Figure 2;

Figure 2b is a schematic representation of the optical device according to a second variant of the configuration illustrated in Figure 2;

Figure 3 is a schematic representation of the optical device according to a second embodiment;

Figure 3a is a schematic representation of the optical device according to a second embodiment, in a first variant of the configuration illustrated in Figure 3;

Figure 3b is a schematic representation of the optical device according to a second embodiment, in a second variant of the configuration illustrated in Figure 3;

Figure 4 is a schematic representation of a light panel forming part of the optical device of Figure 2.

Detailed Description of the Preferred Embodiments of the Invention

The numeral 1 in the accompanying drawings denotes an optical device for indicating the glide angle of aircraft V. With reference to the accompanying drawings, the device 1 comprises at least one light source 2, of predetermined colour, for creating a light image to be projected and forming a light path S for guiding the aircraft V.

The image to be projected is produced by an image creating unit 4 coinciding with the light source 3 itself. The image is then projected at a distance by at least one projection unit 5, preferably comprising an optical lens consisting of suitable lenses 5a.

The light source 3 consists of an electroluminescent panel, preferably of the inorganic LED type, for example a Photonic Lattice LED, or of the organic LED type (an OLED, Organic Light Emitting Diode) or the like.

The image is produced directly on the light surface of the panel 3.

The electroluminescent panel 3 may be embodied by one or more monochrome panels according to the number and colour of the sectors required, placed side by side to make up a single image to be projected.

In other words, the panel may comprise differently coloured areas to produce composite light rays. The light surface thus generates a light beam which is collected by the optical lens of the projection unit 5 so that the beam is projected in such a way as to obtain the light sectors required by the aircraft landing guidance signals.

In an alternative embodiment, the electroluminescent panel 3 may comprise a single polychrome panel on which a single image to be projected is produced. In this embodiment, the light surface consists of an electronically controlled display which allows light shapes to be drawn directly on the display itself.

The light panel 3 is connected to an electrical power supply unit 6 which provides the electric current necessary to power up the panel.

In effect, an electroluminescent panel lights up when electric current passes through it,

The electrical power supply unit 6 comprises devices designed to determine the power-up and power-down states of the light source 2 at a predetermined frequency.

By interrupting the electrical power supply it is possible to produce an intermittent signal, visible in particular at night.

To eliminate the heat produced by the light source 2, the panel 3 is supported by a heat sink 7.

The light panel 3 is mounted immediately upstream of the projection unit 5 and directs the light straight at the optical lens, without there being any interposed transmission elements in between.

The change in the inclination of the light beam S may occur in any of several different ways, whether mechanical, by moving one or more of the component parts of the device 1, or electronic, by acting directly on the image produced on the panel 3.

Whatever the solution adopted, the panel 3 is swivel-mounted so that the light beam can be directed in the desired direction.

Γη a first embodiment, illustrated in Figure 2, the device 1 comprises, the electroluminescent light panel 3, the projection unit 5 and the electrical power supply unit 6.

Advantageously, a control unit 11 may also be provided for guaranteeing the correct orientation of the light beam by checking that the inclination of the entire device 1 is correct. The entire device 1 extends along a substantially horizontal axis la and the panel 3 is mounted in a substantially vertical position.

In the basic configuration, illustrated in Figure 2, the orientation of the light beam S is adjusted by inclining the entire device 1, manually (Figure 2), or through a motor 10 (not illustrated in this configuration), in elevation, pitch and azimuth in order to orient the beam and compensate for the rolling and pitching motion of a platform.

As shown in Figure 1, the angle of elevation of the light beam S is the angle of rotation about the Y-axis, the angle of inclination is the angle of rotation about the X-axis, while the angle of azimuth is the angle of rotation about the Z-axis.

Figure 2a illustrates a configuration where the correct adjustment of the light beam S is obtained by moving only the panel 3.

In this configuration, as illustrated, a motor 10 is provided to move the panel 3 rotationally about the optical axis la and/or translationally along the same optical axis 1a, normal to the plane containing the panel itself. Alternatively, the panel 3 may also be moved manually.

When the motor 10 is provided, the control unit 11 controls the motor 10 and checks the correct angular position of the panel and, hence, of the light beam.

Alternatively to the mechanical movements, correction may also be electronic, as illustrated in Figure 2b.

This involves moving the image created directly on the display of the panel 3. More specifically, this configuration involves the presence of an image processor 15 which processes the image produced and moves or rotates it on the surface of the display of the panel 3, in order to rotate the beam S in two directions. The amount of rotation to be applied is provided by a heave sensor 13.

In any case, both the panel 3 and the entire device 1 can be advantageously moved manually or through the motor 10 suitably connected to and controlled by the control unit 11 which, as stated above, not only controls the motor 10, if provided, but also checks that the light path is correctly oriented.

In a second embodiment, illustrated in Figure 3, the device 1 comprises, in addition to the light panel 3, the projection unit 5 and the electrical power supply unit, a unit 8 for orienting the projected light beam.

In this configuration, too, the device 1 comprises an electrical power supply unit 6 and a control unit 1 1, similar both in structure and operation to the configuration described above. In this case, the device 1 extends along a substantially vertical axis la, the panel 3 is mounted in a horizontal plane and the image produced is oriented in the desired direction by a mirror 9 forming part of the orienting unit 8.

The mirror 9 is swivel-mounted to be suitably oriented by means of the motor 9a controlled by the control unit 11.

In this case, therefore, the control unit 1 1 controls two electric motors 9a and 10.

In the first embodiment, illustrated in Figure 3, the orientation of the panel 3 can be adjusted through the motor 10, by rotating it about the optical axis la of the lens. This rotation, together with that of the mirror 9, makes it possible to obtain the correct orientation of the light path S both in elevation and in inclination. The control unit 11 checks that the orientation is correct. The motor 10 may also move the panel 3 by translating it along the Z-axis normal to the surface of the panel 3 and coinciding with the optical axis la of the lens and/or by inclining it at an angle to the axis 1a (Figure 3).

In an alternative configuration, illustrated in Figure 3a, the orientation of the light beam is adjusted by inclining the assembly made up of the panel 3, the projection unit 5 and the orienting unit 8. In this case, the device substantially comprises the same structural elements as those described in connection with the configuration of Figure 3, except that the motor 10 operates on the whole of the above mentioned assembly.

Also imaginable is a configuration (not illustrated) where the motor 10, suitably connected to the device 1, adjusts the inclination of the entire body of the device 1. In this case, the control unit 11 controls the motor 10 and checks that the entire device is correctly positioned relative to the installation base.

In a further configuration, represented in Figure 3b, the inclination of the light beam is adjusted electronically.

More specifically, the device 1 comprises an image processor 15 which acts in conjunction with the control unit 11 to process the image produced and to move it on the surface of the display of the panel 3 and/or to rotate it appropriately. The electrical power supply unit 6 and the control unit 11 may be integrated in a single electronic unit 12 that may be housed in the device 1 itself or in a physically separate unit.

Where present, the image processor 15 may also be integrated in the electronic unit 12.

The electronic unit 12 controls several parameters of the device, such as, for example, the adjustment of the light intensity or the angular position of the panel.

In any of the configurations described above, the beam orientation angles are supplied to the unit 12 by an operator or by an external unit.

The device 1 may be mounted on movable platforms N, such as ships, for example.

In this case, whatever the configuration of the device 1 , it also comprises a device 13, either outside or inside the electronic unit 12, comprising a heave sensor designed to provide the angular measurement of the inclination of the floating platform N.

This measurement is used by the control unit 11 to orient the light beam by means of the motors 9a and 10, where present, and/or by the processor 15 which moves the images on the display 3, in order to orient the light beam and compensate for the rolling and pitching oscillations of the platform. Compensating these oscillations allows the light beam to be stabilized.

The device 1 also has a transparent protective window 14 of suitable shape. In the configuration illustrated in Figure 3 or 3b, the window 14 may be reduced in size because the panel 3 and the units 5, 8 of the device do not need to rotate relative to the window in order to rotate the beam about the axis la. In effect, the image may be produced with the desired rotation by rotating only the light source.

In the case of the configuration of Figure 3 a, on the other hand, the window 14 must be large enough to allow the light beam to pass through it in all the positions of movement of the panel 3 and of the units 5, 8 relative to the window 14 itself.

The invention brings important advantages and achieves the preset aims. Immediately apparent is the extreme structural and conceptual simplicity of the device described.

Compared to prior art solutions, the light generator and the image creating unit physically coincide in the same unit: the image is created directly by the light source.

That means the device has a limited number of parts.

The image produced directly on the light surface strikes the optical lens directly without going through other units or being conveyed by transmission means: therefore, the light efficiency is extremely high because there are no devices interposed between the light source and the image to be projected.

Moreover, mechanical alignments are not necessaiy to obtain composite images since there is only one image to be projected and it can be produced by adjacent sectors of light elements.

The orientation and stabilization of the beam are achieved by very lightweight parts such as a mirror and/or a panel type light source, which in turn means low power and high response speed.

Alternatively, it can be achieved without moving any parts at all but simply by moving the shape on the surface of an electronically controlled polychrome panel.

Even intermittent light signals for use with night visors can be obtained electrically without moving mechanical parts.

Generally speaking, the device presents reduced dimensions and a veiy compact structure,

Even the vertically extending configuration, stabilized and able to be oriented in elevation, is compact thanks to the possibility of orienting only the light source by moving the panel rotationally and/or translationally along the axis.

Furthermore, it is also possible to adjust the inclination of the light beam without moving any mechanical part but simply by appropriately processing the image.