Patent Description:
High energy laser beams have increasingly been used to disturb transportation vehicles. <NUM> laser incidents have been reported in <NUM>, which is up from <NUM>,<NUM> incidents in <NUM>.

This increasing number of laser beam incidents is an urgent problem, that airlines, airport authorities and law enforcement alike seek solutions to. The practical difficulty lies in the fact, that once board crew has reported an incident, only a rough idea may be available of the location of the source. In darkness this is almost impossible. Since no reasonable information about the location of the source is available, the attackers can rarely be apprehended.

In view of the above, it is an objective of the present invention to provide a possibility to determine the point of origin of a laser beam impacting a window of an aircraft in a timely manner.

Document <CIT> discloses an apparatus for smart window activation wherein a window formed of smart glass is capable of being activated in discrete sections to be impenetrable to laser light and wherein a sensor arrangement detects laser light impacting on the window.

According to the present invention, this problem is solved by a window for an aircraft with the features of independent claim <NUM>, an aircraft with the features of dependent claim <NUM>, and a method for determining the position at which a laser beam impacts a window with the features of independent claim <NUM>.

A further aspect of the invention provides an aircraft comprising a window according to the present invention, wherein the window in particular is configured to be a windshield of a cockpit.

A further aspect of the invention provides a method for determining the point of origin of a laser beam directed at an aircraft according to the present invention.

One idea of the present invention lies in using refracted light to determine the position at which a laser beam impacts the window. As light is refracted in all directions upon traveling between mediums with differing refraction indices, some of the light will travel at angles which impact the circumference of the window. Light detectors arranged around this circumference can measure the intensity of light refracted in these respective directions and these intensities can then be used to determine the position of impact. This position of impact can then be used for a variety of countermeasures as described in the further embodiments of the present invention.

Advantageous embodiments and further developments are apparent from the further dependent claims and from the description with reference to the figures.

According to a further embodiment of the method, the position of impact can be used to determine the point of origin of the laser beam, as will be explained in further detail with reference of the drawings. Determining the point of origin of the laser beam advantageously allows for increased chance of apprehending the person responsible for the emission of the laser beam.

Using two positions the laser beam travels through enables determination of the point of origin with satisfactory accuracy.

According to a further embodiment of the window, at least one of the first plurality of light detectors and second plurality of light detectors are arranged to cover the entirety of the circumference of the first transparent layer or the second transparent layer in regular intervals. This improves the accuracy of determining the point of origin, as a higher portion of the refracted light can be evaluated.

According to a further embodiment, the window further comprises a layer of dimmable electrochromic glass.

According to a further embodiment of the method, the layer of dimmable electrochromic glass is dimmed upon impact of the laser beam on the window.

This provides the advantage that the effect of the laser beam upon persons behind the window can be negated.

According to a further embodiment of the window, the layer of dimmable electrochromic glass comprises a plurality of individually dimmable subsegments.

According to a further embodiment of the method, only the individually dimmable subsegment of the layer of dimmable electrochromic glass in which the laser beam impacts the window is dimmed.

This provides the advantage that visibility through the window is not impaired while negating the effect of the laser beam.

According to a further embodiment of the method, at least one of altitude, roll, pitch, or yaw of the aircraft is used to determine the point of origin of the laser beam. Thus, in particular, in addition to known altitude, the parameters roll, yaw and pitch may be used in combination to determine the point of origin of the laser beam. This can further increase the accuracy when determining the point of origin of the laser beam.

According to a further embodiment of the method, the point of origin of the laser beam is determined utilizing data collected at at least two different points in time. This additional information, in particular as it concerns the position of the vehicle, advantageously increases the accuracy of determining the point of origin of the laser. Further possible embodiments, further developments and implementations of the invention also comprise combinations of features of the invention described above or below with respect to the embodiments which are not explicitly mentioned. In particular, the person skilled in the art will also add individual aspects as improvements or additions to the respective basic form of the present invention.

The present invention is explained in more detail below with reference to the embodiments shown in the schematic figures.

The accompanying figures are intended to provide a further understanding of embodiments of the invention. They illustrate embodiments and, in connection with the description, serve to explain principles and concepts of the invention. Other embodiments and many of the advantages mentioned will be apparent with reference to the drawings. The elements of the drawings are not necessarily shown to scale with respect to each other.

In the figures of the drawings, identical elements, features and components that have the same function and the same effect are each given the same reference signs, unless otherwise specified.

<FIG> shows a schematic illustration of an aircraft <NUM> according to an embodiment of the present invention.

The aircraft <NUM> is flying at a specific altitude above the ground. A laser beam <NUM> is emitted from a point of origin <NUM> on the ground and impacts the aircraft <NUM> at the location of a window <NUM>, in this specific case a windshield of the cockpit.

The situation shown in <FIG> is an example of a situation in which it would be preferable to be able to determine the point of origin <NUM> of the laser beam <NUM>. Various ways how this can be accomplished according to the present invention will be explained in further detail with reference to the following figures.

<FIG> shows a schematic flow chart for a method M to determine the point of origin of a laser beam according to an embodiment of the present invention.

In a first method step M1, an intensity of light refracted upon entering and exiting a first transparent layer of the window is measured by a first plurality of light detectors. In a second method step M2, a position at which the laser beam entered the first transparent layer is determined using the intensity of refracted light measured by each of the first plurality of light detectors. In a third optional method step M3, indicated by dashed lines, the point of origin of the laser beam is determined utilizing the position at which the laser beam entered the first transparent layer.

<FIG> shows schematic flow chart for a method M to determine the point of origin of a laser beam according to another embodiment of the present invention.

The method M shown in <FIG> comprises the method steps shown in <FIG>. Furthermore, between method steps M2 and M3, an intensity of light refracted upon entering and exiting a second transparent layer is measured by a second plurality of light detectors in a method step M4, a position at which the laser beam entered the second transparent layer is determined using the intensity of refracted light measured by each of the second plurality of light detectors in a method step M5, and an angle at which the laser beam impacted the window is determined utilizing the position at which the laser beam entered the first transparent layer and the position at which the laser beam entered the second transparent layer in a method step M6. In a further method step M7, a layer of dimmable electrochromic glass is dimmed upon impact of the laser beam on the window.

In general, the laser beam in question will impact the window for an extended period of time. Consequently, the various method steps shown in <FIG> and <FIG> can also be performed repeatedly over said extended period of time. In particular, the position and the angle of impact of the laser beam can be determined at various points in time, at which the aircraft will be located at different positions. With this additional data, the point of origin of the laser beam can be determined with increased accuracy.

How the method steps of the methods shown in <FIG> and <FIG> are carried out according to the present invention will be further explained with reference to the following figures.

<FIG> shows a schematic illustration of a window <NUM> for an aircraft according to an embodiment of the present invention in a front view. <FIG> shows a schematic illustration of a window <NUM> for an aircraft according to an embodiment of the present invention in a side view.

The window <NUM> comprises a first transparent layer <NUM> and a first plurality of light detectors <NUM> arranged around a circumference of the first transparent layer <NUM>. The first plurality of light detectors <NUM> are configured to measure the intensity of light refracted upon entering and exiting the first transparent layer <NUM>.

A laser beam <NUM> enters the first transparent layer <NUM> at a position <NUM>. Upon entering the first transparent layer <NUM>, some portion of the light of the laser beam <NUM> will be refracted in all directions due to a difference in refraction index between the first transparent layer <NUM> and the ambient medium, which might be air or another transparent layer of the window <NUM>. Some of the refracted light will be received by each of the first plurality of light detectors <NUM>, which will then measure the intensity of light refracted in its respective direction. The intensity measured by each light detector <NUM> will depend in great parts on the distance the refracted light has traveled through the first transparent layer. The values for the intensities measured by each of the first plurality of light detectors <NUM> can therefore be used to determine the position <NUM> at which the laser beam <NUM> has entered the first transparent layer <NUM>.

<FIG> shows a schematic illustration of a window <NUM> for an aircraft according to a further embodiment of the present invention.

The window <NUM> comprises a first transparent layer <NUM>, a second transparent layer <NUM>, a layer of dimmable electrochromic glass <NUM>, a first plurality of light detectors <NUM> arranged around a circumference of the first transparent layer <NUM>, and a second plurality of light detectors <NUM> arranged around a circumference of the second transparent layer <NUM>. The first plurality of light detectors <NUM> are configured to measure the intensity of light refracted upon entering and exiting the first transparent layer <NUM>. The second plurality of light detectors <NUM> are configured to measure the intensity of light refracted upon entering and exiting the second transparent layer <NUM>.

A position <NUM> at which a laser beam <NUM> enters the first transparent layer <NUM> is determined as has been described with respect to <FIG>. A position <NUM>, at which the laser beam <NUM> enters the second transparent layer <NUM> can be determined in an analogous way, only using the intensities of light measured by the second plurality of light detectors <NUM> instead of the those measured by the first plurality of light detectors <NUM>. The positions <NUM> and <NUM> relative to each other can be determined as the thicknesses of the first transparent layer <NUM> and the second transparent layer <NUM> are known. Knowing the positions <NUM> and <NUM> at which the laser beam <NUM> enters the first transparent layer <NUM> and the second transparent layer <NUM> respectively, an angle α at which the laser beam <NUM> impacts the window <NUM> can be determined using basic trigonometric calculations. Looking at <FIG>, the point of origin <NUM> of the laser beam <NUM> can now be determined using the angle α and the altitude of aircraft <NUM>. To improve the results of this determination, it can be beneficial to take the roll, pitch, and/or yaw of the aircraft <NUM> into account.

The window <NUM> shown in <FIG> further comprises a layer of dimmable electrochromic glass <NUM>. The function of this layer of dimmable electrochromic glass <NUM> will be described in more detail with reference to <FIG>.

The present invention is not limited to the configuration of layers shown in <FIG>. In particular, the first transparent layer <NUM> and second transparent layer <NUM> do not have to be adjacent to each other and the layer of dimmable electrochromic glass <NUM> is not necessarily directly adjacent to the second transparent layer <NUM>.

The window <NUM> comprises a layer of dimmable electrochromic glass <NUM>, which comprises a plurality of individually dimmable subsegments <NUM>.

When a laser beam impacts the window <NUM> at a position <NUM>, the layer of dimmable electrochromic glass <NUM> can be dimmed in response, negating the effect of the laser beam on persons behind the window <NUM>.

Using electrodes arranged in a grid-like manner, the layer of dimmable electrochromic glass <NUM> can be divided into a plurality of individually dimmable subsegments <NUM>. As the position <NUM> of the laser beam can be determined as described with respect to the preceding figures, it is possible to only dim the individually dimmable subsegment <NUM> in which the position <NUM> is located, thereby negating the effect of the laser beam without compromising the visibility through the window <NUM> as a whole.

Throughout the present application, reference has been made to "determining the position at which a laser beam enters a layer". This is to be understood as a simplified formulation used to increase the legibility of the present application. In real applications, light can be refracted upon entering and/or exiting a layer, depending on the differences in refraction index between the respective layer and adjacent mediums. Consequently, the formulation "determining the position at which a laser beam enters a layer" can also encompass the case where a position at which a laser beam exits a layer is determined in the context of the present invention. In case that light is significantly refracted upon both entering and exiting a layer, "determining the position at which a laser beam enters said layer" should be understood as encompassing "determining an average between the position at which a laser beam enters said layer and the position at which the laser beam exits said layer". Looking at the example shown in <FIG>, if the two transparent layers <NUM> and <NUM> are made from the same material, little to no refraction should happen at the border between the two transparent layers <NUM> and <NUM>. Significant refraction only happens at the positions where the laser beam <NUM> enters the first transparent layer <NUM> and exits the second transparent layer <NUM>. In that case, with the methods described in the present application, a position where the laser beam enters the first transparent layer <NUM> and a position where the laser beam exits the second transparent layer <NUM> can be determined. These positions can then be utilized to determine the point of origin of the laser beam <NUM> as described.

Claim 1:
Window (<NUM>) for an aircraft (<NUM>), the window (<NUM>) comprising a first transparent layer (<NUM>),
a first plurality of light detectors (<NUM>) arranged around a circumference of the first transparent layer (<NUM>) and configured to measure the intensity of light refracted upon entering and exiting the first transparent layer (<NUM>) and determine an average between a position at which a laser beam enters the first transparent layer (<NUM>) and a position at which the laser beam exits
the first transparent layer (<NUM>), further comprising
a second transparent layer (<NUM>), and
a second plurality of light detectors (<NUM>) arranged around a circumference of the second transparent layer (<NUM>) and configured to measure the intensity of light refracted upon entering and exiting the second transparent layer and determine an average between a position at which a laser beam enters the second transparent layer (<NUM>) and a position at which the laser beam exits the second transparent layer (<NUM>).