Active anti-dazzle device for the drivers of cars and other motor vehicles

Abstract: The device has an electrical circuit (1) consisting of an optic sensor (2) which provides an output sensing signal (Ve) proportional to the value of the luminosity intercepted in the sensor's field of reception at a specific angle (α); the optic sensor is designed to transmit the said signal to a measuring/comparing circuit (4) where it is compared with a preset threshold value (Vc); when the value of the sensing signal (Ve) exceeds the threshold value (Vc), the circuit (4) transmits an actuating signal (S) to the power supply unit (4a) of an electro-sensitive screen (5) which is designed to pass from a state of total transparency, when there is no actuating signal (S), to a partially darkened or coloured state, when the actuating signal is transmitted (S), and back again to its transparent state when actuating signal transmission ceases.

Description: This invention is an anti-dazzle device positioned in the field of vision of the driver of a car or other motor vehicle. It is common when driving on roads or motorways to be dazzled by the rays of the rising or setting sun or, at night, to be dazzled by the headlights of oncoming vehicles. Dazzle caused by the sun and headlight is very annoying for a driver (especially when meeting a column of cars coming in the opposite direction or during rain when visibility is reduced and reflections from the road surface are increased) and is also a very serious road traffic hazard which can lead to accidents; dazzle is particularly common on badly lit roads requiring the use of headlights on main beam which are not always dipped by drivers when meeting oncoming traffic. US-A-4 848 890 discloses an active anti-dazzle device for drivers of cars and other motor-vehicles comprising: an electro-sensitive screen positioned between a driver and an oncoming beam of light, said electro-sensitive screen consisting of a liquid crystal glass strip; power supply means for supplying power to said electro-sensitive screen; an optical sensor having a field of reception at a specific angle and being responsive to the luminosity intercepted in the field of reception at the specific angle for generating a sensing signal output proportional to a value of the luminosity intercepted; measuring/comparing means for comparing the sensing signal output with a threshold value and for transmitting an actuating signal to said power supply means in response to the sensing signal output exceeding the threshold value and for ceasing transmission of said actuating signal in response to the sensing signal output being beneath the threshold value, said power supply means being capable of receiving said actuating signal for causing said electro-sensitive screen to leave a state of total transparence to enter into a partially darkened or coloured state, said power supply means being responsive to an absence of said actuating signal, as results in response to said measuring/comparing means for ceasing transmission and restoring said electro-sensitive screen to the state of total transparence. The main disadvantage of the device described in US-A-4 848 890 is that the power supply means are not capable of receiving the actuating signal for causing said electro-sensitive screen to leave a state of total transparence to enter into a partially darkened or coloured state. In addition, the following functions are not solved by the device described in US-A-4 848 890: pivoting functions for rotating said electro-sensitive screen with respect to the windscreen of the vehicle within the field of the vision of the driver; and adjusting functions for adjusting said screen so that it is movable along a minimum of two axes which are at right angles to each other. The aim of the present invention is to remedy to the above drawbacks. The invention, as claimed, solves the problem of creating an active anti-dazzle device for drivers of cars and other motor-vehicles, by means of which said electro-sensitive screen is rotated about pivots with respect to the windscreen of the vehicle, said rotation taking place within the field of the vision of the driver. The advantages offered by the present invention are due to the fact that adjusting devices are used for adjusting said screen so that it is movable along a minimum of two axes which are at right angles to each other. In one embodiment the active anti-dazzle device for drivers of cars and other motor-vehicles comprises: an electro-sensitive screen positioned between a driver and an oncoming beam of light, said electro-sensitive screen consisting of a liquid crystal glass strip; power supply means for supplying power to said electro-sensitive screen; an optical sensor having a field of reception at a specific angle and being responsive to the luminosity intercepted in the field of reception at the specific angle for generating a sensing signal output proportional to a value of the luminosity intercepted; measuring/comparing means for comparing the sensing signal output with a threshold value and for transmitting an actuating signal to said power supply means in response to the sensing signal output exceeding the threshold value and for ceasing transmission of said actuating signal in response to the sensing signal output being beneath the threshold value, said power supply means being capable of receiving said actuating signal for causing said electro-sensitive screen to leave a state of total transparence to enter into a partially darkened or coloured state, said power supply means being responsive to an absence of said actuating signal, as results in response to said measuring/comparing means for ceasing transmission and restoring said electro-sensitive screen to the state of total transparence; wherein pivoting means are provided for rotating said electro-sensitive screen at least on one side with respect to a support fitted in a frame at a side of the windscreen of a motor-vehicle within the field of the vision of the driver, the support supporting the electro-sensitive screen on the frame; and adjusting means for adjusting said screen so that the screen is movable along a minimum of two axes which are at right angles to each other, said screen being fitted with the optical sensor, said adjusting means comprising an elongated sleeve capable of rotating about an axis and an extendible arm. The advantages and characteristics of this invention are described in greater detail below where reference is made to the enclosed drawings which represent one possible form or the invention and are not to be interpreted as being in any way restrictive. the drawings are as follows. figure 1 shows a block diagram of the device described in this invention; figures 2 and 3 show a side and a front view, respectively, of the device in figure 1 fitted to a motor vehicle; With reference to the drawings, the anti-dazzle device for the drivers of cars and other motor vehicles covered by this invention consists of a complete electrical circuit 1 (see fig. 1) comprising an optic sensor 2 providing a sensing output signal (indicated by Ve) proportional to the value of luminosity intercepted in the sensor's field of reception at a specific angle (indicated by α) of a beam of light 3 coming from oncoming headlights (on main beam) or the rising/setting sun. This optic sensor 2 transmits the signal Ve to a measuring/comparing circuit 4 where the signal Ve is compared with a preset threshold value (indicated by Vc in fig. 1); when the sensed signal Ve exceeds the preset threshold value Vc, the said measuring circuit 4 will output an actuating signal S to the power supply unit 4a (a simple diode, for example) of an electro-sensitive screen 5. This screen 5 is designed to pass from a state of total transparency, when there is no actuating signal S, to a partially darkened or coloured state when the actuating signal S is received; the screen 5 will pass back to its transparent state again when transmission of the actuating signal S ceases. The electro-sensitive screen 5, as shown here, could consist of a mainly horizontal glass strip, with a liquid crystal layer, positioned between the driver and the source of the beam of light 3. The optical sensor 2 could be positioned above the glass strip and could be fitted with a guide G to permit adjustment along the glass strip in accordance with the characteristics of the motor vehicle to which it is fitted. A possible version of the invention is shown in figures 2 and 3 where the electro-sensitive screen 5 pivots at one of its sides on a support 6 fixed to the frame 7 of the motor vehicle 15 at the side the vehicle's windscreen 8 at the same position as the driver's field of vision; between the support 6 and the screen 5 there are means 9 for adjusting the screen 5 so that it can be moved along a minimum of two axes which are at right-angles to each other. The adjustment means 9 consist of a sleeve 16, fitted over a support 6, which rotates on its vertical axis and which can be fitted with a stop screw or other friction device (not shown here) to hold it in position; the sleeve 16 is joined to the screen 5 by a horizontal arm 17 (preferably telescopic) so as to permit horizontal and vertical adjustment of the screen to meet the driver's requirements. The above description clearly shows that the device fully meets the purposes for which it was designed. It should also be noted that the time taken for the screen to darken is considerably less than the time taken for the human eye to react and adept do dazzle. When the screen is in use the eye's pupils do not therefore have to work so hard and there is a consequent reduction in eye strain during night driving. A further possible improvement would be to fit the circuit of the device with solar batteries.

Claims: An active anti-dazzle device for drivers of cars and other motor-vehicles, comprising: an electro-sensitive screen (5) positioned between a driver and an oncoming beam of light (3), said electro-sensitive screen (5) consisting of a liquid crystal glass strip; power supply means (4a) for supplying power to said electro-sensitive screen (5); an optical sensor (2) having a field of reception at a specific angle (α) and being responsive to the luminosity intercepted in the field of reception at the specific angle (α) for generating a sensing signal output (Ve) proportional to a value of the luminosity intercepted; measuring/comparing means (4) for comparing the sensing signal output (Ve) with a threshold value (Vc) and for transmitting an actuating signal (S) to said power supply means (4a) in response to the sensing signal output (Ve) exceeding the threshold value (Vc) and for ceasing transmission of said actuating signal (S) in response to the sensing signal output (Ve) being beneath the threshold value (Vc); said power supply means (4a) being capable of receiving said actuating signal (S) for causing said electro-sensitive screen (5) to leave a state of total transparence to enter into a partially darkened or coloured state, said power supply means (4a) being responsive to an absence of said actuating signal (S), as results in response to said measuring/comparing means (4) for ceasing transmission and restoring said electro-sensitive screen (5) to the state of total transparence; characterised by the fact that the following elements are provided: pivoting means for pivoting said electro-sensitive screen (5) at least on one side with respect to a support (6) fitted to a frame (7) at a side of a windscreen (8) of a motor-vehicle within the field of the vision of the driver, the support (6) supporting the electro-sensitive screen (5) on the frame (7); and adjusting means (9) for adjusting said screen (5) so that the screen (5) is movable along a minimum of two axes which are at right angles to each other, said screen (5) being fitted with the optical sensor (2), said adjusting means (9) comprising an elongated sleeve (16) rotating about an axis and an extendible arm (17).

Inventors: AGOSTINI ALBERTO, AGOSTINI GIORGIO, NOLI MARCO, AGOSTINI, ALBERTO, AGOSTINI, GIORGIO, NOLI, MARCO
Applicants: AGOSTINI ALBERTO, AGOSTINI GIORGIO, NOLI MARCO, AGOSTINI, ALBERTO, AGOSTINI, GIORGIO, NOLI, MARCO
Application year: 1991
Main classification: B60J3
IPC codes: B60J3, A42B3