AU2006200700A1 - Anti Distraction System - Google Patents

Description

21/02 '06 16:30 FAX 613 8618 4199 FB RICE CO. i oo005 1

AUSTRALIA

Patents Act 1990 Eurovox Pty Ltd COMPLETE SPECIFICATION Invention Title: Anti Distraction System The invention is described in the following statement: COMS ID No: SBMI-02742306 Received by IP Australia: Time 16:30 Date 2006-02-21 21/02 '06 16:30 FAX 613 8618 4199 FB RICE CO. [a 006 8 2 C) Anti Distraction System C-i Field of the Invention This invention relates to an anti-distraction system and particularly relates to an anti-distraction system for use in vehicles.

oBackground to the Invention In a vehicle 10 with an existing rear seat entertaining (RSE) system, whether omounted in the roof, centre console or headrest, the visual display unit or monitor 12 of such a system, (see Figure is easily seen by all passengers seated rearward and facing the monitor 12. For ease of reference the monitor is displaying the letter This typical installation also allows people outside the vehicle to view the screen images, which can be very distracting to people travelling in other vehicles behind or to the side of the vehicle.

Screens in vehicles currently include a linear polariser on the screen output, so that the electromagnetic field of all light emitted by the screen is confined in one plane.

This is referred th as the transmission axis of the screen. However, people outside the vehicle can still view and be distracted by images on the screen monitor when located in the same plane containing the emitted light The present invention seeks to overcome the abovementioned disadvantages by providing an anti-distraction system that substantially reduces the possibility of persons exterior to the vehicle, installed with having the monitor, being able to see the images on the monitor. The invention is designed to substantially reduce or eliminate distraction caused to third party veicles from screen based moving images operating within a vehicle.

Tbroughout this specification the word "comprise", or variations such as "comprises" or "comprising", will be understood to imply the inclusion of a stated element, integer or step, or group of elements, integers or steps, but not the exclusion of any other element, integer or step, or group of elements, integers or steps.

Any discussion of documents, acts, materials, devices, articles or the like which has been included in the present specification is solely for the purpose of providing a context for the present invention. It is not to be taken as an admission that any or all of these matters form part of the prior art base or were common general knowledge in the m:\specifcatona\OOO\O50400oO 50 .4 COMS ID No: SBMI-02742306 Received by IP Australia: Time 16:30 Date 2006-02-21 21/02 '06 16:31 FAX 613 8618 4199 FB RICE CO. 0007

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0 3 field relevant to the present invention as it existed before the priority date of each claim of this application.

Summary of the Invention According to an aspect of the invention there is provided a system for 0 substantially preventing viewing of images on a visual display unit located in one o location, from another location, the system comprising: 0 the visual display unit; IN) first polariser means located at the visual display unit for polarising light emitted o 10 from the unit, second polarising means placed between the visual display unit and an observer located in said another location such that the second polarising means cross-polarises the light emitted from the first polarising means wherein the observer is substantially unable to view any image displayed on the visual display unit when located in the another location.

The one location may be the interior of a vehicle. The visual display unit may be installed on the interior roof, a headrest or console area such the unit can be readily seen from outside the vehicle by, for example, a driver or passenger in another vehicle.

The another location may be any location external to the vehicle. The system has particular application where the display unit is mounted in such a marnner that occupants in the rear of the vehicle can see the display but occupants in another vehicle, following the first mentioned vehicle in traffic, cannot see the display.

The one location may be a room partly bounded by glass or other transparent media and the another location may be a position external to the room.

The polarising material or second polarising material has an axis of transmission set to approximately 90 degrees to the axis of transmission of the polariser or the first polarising material respectively.

The system of the present invention preferably applies a polarising system to the back and/or side windows of a vehicle having an RSE system. The polarising system may involve the application of an adhesive polarized film or some other polarisation process incorporated during glass manufacture. If the polarisation effect is set to with respect to the screen polariser, the RSE screen is rendered invisible externally when viewed through any of the polarised windows.

m:\speifications\500000\504000\504185capreo.doc COMS ID No: SBMI-02742306 Received by IP Australia: Time 16:30 Date 2006-02-21 21/02 '06 16:31 FAX 613 8618 4199 FB RICE CO. @]008 Va

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0 4 .3 Brief Description of the Drawings The invention will hereinafter be described in one or more preferred embodiments, by way of example only, with reference to the drawings wherein: Figure 1 is a side view showing an occupant of a vehicle viewing a visual display unit mounted to the vehicle roof interior; o Figure 2 is a rear view of a vehicle with polarising material partly fitted to a rear o window showing the effect of viewing the display unit through the material; 0, Figure 3 illustrates an axis of light transmission of a polariser; NO Figure 4 shows two polarisers aligned at the same angle of polarisation and their effect on light passing therethrough; and

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l Figure 5 shows two polarisers aligned at 90 degrees with one another and their effect on light passing therethrough.

Detailed Description of Preferred Embodiments The anti distraction system utilises the concept of crossed polarisers derived from Malus's Law for linear polarisers which states that for two polarisers with axes of transmission set to 90° (or 'crossed') it will reduce the transmission of light through the second polariser to nil when the two polarisers are ideal.

In Figure 2 there is shown a vehicle 20 having a polarising material applied to a portion 22 of the rear window 24 which is angled at 90 with respect to the axis of transmission of light emanating from the visual display screen or monitor 26. It shows the effect when the polariser is applied to only half the rear window of vehicle 20 with a RSE system operating. The polarised area 22 is unable to allow viewing of the letter from behind vehicle 20 on the monitor 26. The area 28 of the rear window 24 where no polarised filter is applied can easily distinguish the letter and any other image that may be displayed. If the whole of the rear window 24 had been polarised, the entire image displayed on monitor 26 could not be recognised whilst viewing through the rear window 24.

As the polarising material or filter, once applied to the vehicle 20, only eliminates polarized light, natural light still permits viewing of objects inside the vehicle 20 and also for people inside the vehicle to view objects and people through the rear and side windows as normal. There is no adverse impact on the driver of the vehicle if wearing polarized sunglasses as the film is not 90° out of phase with the m.\specifications\600000504000\504185capreo.doc COMS ID No: SBMI-02742306 Received by IP Australia: Time 16:30 Date 2006-02-21 21/02 '06 16:31 FAX 613 8618 4199 FB RICE CO. 0009

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Spolarized sunglasses. There is also no deterioration in performance when the rear window 20 is not perfectly parallel to the monitor 26, c,1 Malus's Law for linear polarisers states that the transmission of light through two ideal polarisers is given as; 0 T cos 2 100 (1) 0 Where T is the percentage of light transmitted through the two polarisers when IN their axes of transmission are aligned with angle 0. Figure 3 displays the axis of o 10 transmission of a polarising material 30, such as a film or filter, which helps indicate what direction the polariser is orientated in for further images. The axis is oriented vertically in this case.

When the two polarisers are aligned in the same direction (0 00) Malus's Law predicts that the transmission of light through the second polariser will be: cos 2 0 co 2 (00) 1 therefore T 100% Figure 4 shows the effect of having both polarisers 40 and 42 aligned at the same angle of polarisation. In this case no light will be absorbed by the second polariser 42 and all light will be transmitted. When the parameter T 100%, then no light is absorbed by the polarisers 40 and 42.

With reference to Figure 5, the angle formed by the two transmission axes of the polarisers 50, 52 is 90° and result is cos 2 9 cos 2 (900) 0 therefore T= 0% Figure 5 shows the effect of having both polarisers aligned 900 with respect to their axis of transmission. In this case all light will be absorbed by the second polariser 52 and no light will be transmitted. Therefore, T 0% where all the light is absorbed by the polarisers 50, 52.

The polarisers may not be ideal, and therefore some light from the RSE monitor 26 may be seen from outside the vehicle. The embodiment aims to reduce the intensity of light emitted from the RSE monitor 26 to a level below which it cannot be deemed a m:;specifications6500000\50400050418capreo.doc COMS ID No: SBMI-02742306 Received by IP Australia: Time 16:30 Date 2006-02-21 21/02 '06 16:32 FAX 613 8618 4199 FB RICE CO. @010 6 distraction to other road users. In the case that the approximation for ideal polarisers cannot be used, Malus's Law can be used for non ideal polarisers, given the following: T (Tm. Tm.) CO 2 0 Tmin 100 This gives a transmission of Tmin when the two polarisers are crossed by By selecting a polariser that has a very small value of Tmin (common polarisers have extinction values less than it is possible to reduce the amount of light escaping the rear window to an amount that is negligible, and not of a distracting intensity.

It will be appreciated by persons skilled in the art that numerous variations and/or modifications may be made to the invention as shown in the specific embodiments without departing from the spirit or scope of the invention as broadly described. The present embodiments are, therefore, to be considered in all respects as illustrative and not restrictive.

m:\specifications\500000\504000\5041 COMS ID No: SBMI-02742306 Received by IP Australia: Time 16:30 Date 2006-02-21

Claims (8)

1. A system for substantially preventing viewing of images on a visual display unit located in one location, from another location, the system comprising: the visual display unit; first polariser means located at the visual display unit for polaising light emitted from the unit, second polarising means placed between the visual display unit and an observer INO located in said another location such that the second polarising means cross-polarises othe light emitted from the first polarising means wherein the observer is substantially unable to view any image displayed on the visual display unit when located in the another location.

2. A system according to claim 1 wherein the one location is the interior of a vehicle.

3- A system according to claim 1 or claim 2 wherein the another location is external to the vehicle.

4. A system according to claim 1 wherein the one location is an area partially or fully bounded by transparent media- A system according to claim 1 or claim 4 wherein the another location is external to the area partially or fully bounded by transparent media.

6. A system according to claim 2 or claim 3 wherein the visual display unit is installed on the interior roof of the vehicle or a headrest or console area within the vehicle such the unit is able to be seen exterior to the vehicle.

7. A system according to any one of the previous claims wherein the first polarisiug means and the second polarising means is a filter or polarising material, m-\specif'ations500000O\54000\504185capmo.doc COMS ID No: SBMI-02742306 Received by IP Australia: Time (IH:m) 16:30 Date 2006-02-21 21/02 '06 16:32 FAX 613 8618 4199 FB RICE CO. [@012 INO 88 C)

8. A system according to claim 7 wherein the second polarising means has an axis of transmission set to approximately 90 degrees to the axis of transmission of the first NC polarising means,

9. A system according to claim 8 wherein the first or second polarising means is an adhesive polarized film. A system for substantially preventing viewing of images on a visual display unit located in one location, from another location substantially as hereinbefore described with reference to the accompanying drawings. Dated this twenty-first day of February 2006 Eurovox Pty Ltd Patent Attorneys for the Applicant: F B RICE CO m:\specifications\500000\504000\504185capreo.doc COMS ID No: SBMI-02742306 Received by IP Australia: Time 16:30 Date 2006-02-21