WO1996020846A1

WO1996020846A1 - Method and device for forming luminous fluxes acting on the organ of sight of a transport vehicle driver

Info

Publication number: WO1996020846A1
Application number: PCT/EP1995/000018
Authority: WO
Inventors: Vladimir Romanovskij
Original assignee: BALEANI PIERGIORGIO; BENCO Srl
Current assignee: BALEANI PIERGIORGIO; BENCO Srl
Priority date: 1995-01-04
Filing date: 1995-01-04
Publication date: 1996-07-11
Anticipated expiration: 1997-07-04
Also published as: AU1385495A

Abstract

The essence of the invention resides in that an intensity (J) of a luminous flux (Ζ) perceived by driver's eyes (1) is periodically reduced by alternating periods (tp, to) of transmission or attenuation of the luminous flux (Ζ). The luminous flux intensity (J) is reduced with the aid of controlled light filters (5) with a variable translucency (Tr) located on the transport vehicle being driven and adapted to be brightened for the period (tp) of brightening pulses (TrI), or be attenuated for the period (to) of attenuation, with the pulse repetition period T. The apparent brightness reduction ratio is equal to T/tp. Lighting units (3) of the transport vehicle being driven generate a luminous flux as a sequence of light pulses (I3) in synchronism with the brightening pulses (TrI), a frequency (F) of the light pulses (I3) exceeding ten pulses per second.

Description

METHOD AND DEVICE FOR FORMING LUMINOUS FLUXES ACTING ON THE ORGAN OF SIGHT OF A TRANSPORT VEHICLE DRIVER

The present invention refers generally to lighting technology and more specifically it relates to a method for forming luminous fluxes acting on the organ of sight of the driver of a transport vehicle and to a device for carrying out said method.

The invention can find application in any transport vehicle.

One state-of-the art device for forming luminous fluxes acting on the organ of sight of the driver of a transport vehicle (cf. the journal "Za rulio " (Motoring) No. 10, 1983, K.N. Sachkov "On liquid crystals", p. 9 (in Russian) comprises a light source and a controlled light filter spaced closely apart from said light source, said device carrying into effect a method consisting in that when driving under conditions of poor road illumination an electric signal is applied to the controlled light filter, with the result that the light filter acquires the properties of a light-diffusing optical body. Thus, the directional pattern of the luminous flux emitted by the light source is changed, thereby reducing the glaring effect of said luminous flux on the eyes of the drivers of other transport vehicles.

Devices of the above type must be installed on every transport vehicle; besides, such a vehicle cannot be driven by a dazzled driver without impairing another transport vehicle.

Another prior-art method for forming luminous fluxes acting on the organ of sight of the driver of a transport vehicle (US, A, A,623,222) consists in that the intensity of a luminous flux acting on the driver's sight is attenuated by being passed preliminarily through controlled light filters installed on the driven transport vehicle. Transparency of the light filters varies stepwise depending on the intensity of the luminous flux incident thereon; in this case the entire luminous flux that acts on the driver's sight is attenuated: i.e. both the flux emitted by external light sources and the flux emitted by the lighting units of the vehicle (that is, the head-lamps of the driven transport vehicle). This however, entails an undesiderable reduction of the road illumination level for the vehicle driver.

A device carrying into effect the known method as per US Patent A, ,623,222, comprises controlled light filters based on variable- _ ? _

transparence liquid crystals arranged on the driven transport vehicle and connected to a generator of control pulses which appears as an electric pulse generator.

The known device fails to provide a possibility for separately attenuating luminous fluxes emitted by external light sources and by the lighting units of the driven transport vehicle and incident on the light filter as an integrated luminous flux. In addition, transparency of the light filters varies stepwise because there is no possibility for changing the relative duration of the control pulse applied to the light filters; that is why the attenuation of the intensity of a luminous flux emitted by external light sources cannot be controlled.

The present invention has for its essential object to provide a method for forming luminous fluxes acting on the organ of sight of a transport vehicle driver, featuring such a formation of the luminous flux emitted by the lighting units of a driven transport vehicle to illuminate the road, and such a reduction of the intensity of a total luminous flux emitted that make it possible to decrease the luminous flux from external light sources which acts on the driver's sight and at the same time to retain invariable that part of the luminous flux which is perceived by the driver from the lighting unit of the driven transport vehicle; the invention is also aimed at providing a device for carrying into effect said method whose circuitry design be instrumental in separating the luminous fluxes emitted by external light sources from those emitted by the lighting units of the driven transport vehicle, as well as bringing the light pulses generated by the lighting units of the driven transport vehicle in synchronism with the brightening pulses of the controlled light filters.

According to the invention, this object is achieved by a method for forming luminous fluxes acting on the organ of sight of a transport vehicle driver, consisting in that the intensity of the luminous flux perceived by the driver's eyes and composed of the luminous fluxes emitted by the lighting units of the driven transport vehicle and by external light sources, is periodically reduced before the luminous flux gets incident on the driver's eyes, by alternating the periods of transmission and attenuation of the luminous flux acting on the driver's sight, according to the invention, the luminous flux emitted by the lighting units of the driven transport vehicle is formed as a sequence of light pulses synchronous with the periods of luminous flux transmission, the maximum frequency of said light pulses being ten pulses per second.

It is expedient, with a view to separating the luminous fluxes generated by external light sources, e.g., the lighting units of the oncoming transport vehicles, from those emitted by the lighting units of the driven transport vehicle, with the luminous flux emitted by external light sources as a sequence of light pulses, that the periods of transmission of the luminous flux acting on the driver's sight be time-displaced with respect to the light pulses from external sources.

It is also expedient that, with a view to a greater attenuation of the most intense luminous fluxes dazzling the driver of the transport vehicle being driven, the intensity of the luminous flux perceived by the driver's eyes be reduced nonuniformly within the angle of the driver's visual field so as to reduce the luminous flux intensity within the solid angles confining external light sources.

To properly regulate the operation of lighting units of many transport vehicles which generate pulsed luminous fluxes, use is made of an externally applied radio signal against which the periods of transmission or attenuation of the luminous fluxes of a group of oncoming transport vehicles are brought in synchronism.

The foregoing object is also accomplished due to the fact that in a device for forming of luminous fluxes acting on the organ of sight of a transport vehicle driver, comprising lighting units situated on the transport vehicle being driven, controlled light filters featuring variable transparency for reducing the intensity of the luminous flux perceived by the driver, situated also on the transport vehicle being driven, and a generator of control signals electrically connected to the light filters, according to the invention, at least one of the lighting units appears as a pulsed light source electrically connected to the generator of control signals.

To bring the operation of the present device in accordance with the operation of similar devices on other transport vehicles, it is necessary that it comprises additionally a detector of light signals from other transport vehicles which is connected to the generator of control signals.

With a view to reducing the effect of bright light on the driver of a transport vehicle, said light being emitted by small-size sources, the controlled light filters are made as mosaic structures constituted by a number of elementary light filters.

It is expedient that control of variation in the transparency of the elementary light filters be performed with the aid of a coordinate system additionally provided in the device and electrically connected to each of the elementary light filters.

It is preferable that, with a view to regulating the control signal, the device comprise additionally a detector of radio signals connected to the generator of control signals and located on the transport vehicle being driven.

It is preferable that, with a view to generating adequately bright light flashes by the light sources located on the transport vehicle being driven, a gaseous-discharge flash lamp be used as a pulsed light source.

In the following the present invention will be disclosed by a detailed description of some specific exemplary embodiments thereof with reference to the accompanying drawings, wherein:

FIG. 1 is a diagram showing the method for forming luminous fluxes acting on the organ of sight of a transport vehicle driver, according to the invention;

FIG. 2 shows time diagrams of the luminous flux intensity before getting incident on the driver's eyes and after the intensity has been reduced for acting on the driver's sight in accordance with the periods of luminous flux transmission and attenuation;

FIG. 3 shows time diagrams of the intensity of the luminous flux emitted by external light sources before getting incident on the driver's eyes and after periodical reduction of said intensity with a variable duration of the light filter brightening pulses;

FIG. 4 shows the same diagram as FIG. 3, with a variable repetition frequency of the light filter brightening pulses;

FIG. 5 shows time diagrams of intensity of the luminous fluxes appearing as a sequence of light pulses emitted by external light sources and by the lighting units of the transport vehicle being driven;

FIG. 6 shows time diagrams illustrating the proposed method involving the use of an externally applied radio signal;

FIG. 7 shows a diagram showing the proposed method with a nonuniform reduction of the luminous flux intensity within the angle of the driver's visual field;

FIG. 8 shows time diagrams of the luminous flux intensity when it is reduced spatially nonuniformly with a different duration of the light filter brightening pulses;

FIG. 9 shows the same diagrams as FIG. 8, with different repetition frequencies of the light filter brightening pulses;

FIG. 10 shows a light path diagram of a device for forming luminous fluxes acting on the organ of sight of the driver of a transport vehicle, according to the invention;

FIG. 11 shows an alternative embodiment of the device of FIG. 10, provided with an optic coordinate system and mosaic-structure controlled light filters;

FIG. 12 shows the construction arrangement of a lighting unit, comprising a gaseous-discharge flash lamp with two discharge gaps; and

FIG. 13 shows a light path diagram of a device, wherein controlled light filters are situated at the surface of the rear-view mirrors.

The herein-proposed method for forming luminous fluxes acting on the organ of sight of the driver of a driven transport vehicle is carried out as follows.

The total luminous flux φ (FIG. 1) having an intensity J (FIG 2 )_t _Deceived by the eyes 1 of the driver of a transport vehicle, consists of a luminous flux ^ having an intensity J ^ and emitted by an external light source 2, e.g., the lighting unit of an oncoming transport vehicle or by the Sun, and a luminous fluxC 2 generated by head-lamps 3 of the transport vehicle being driven. The head-lamps 3 illuminate, e.g., a pedestrian 4; in this case part of the luminous flux φ 2 is diffused by the pedestrian 4 in the form of a luminous flux φ 3 having an intensity J 3. The intensity of the luminous flux φ is periodically reduced before its getting on the driver's eyes 1, by passing said luminous flux through, e.g., controlled light filters 5 having variable transparency Tr and governed with the use of a generator 6 of control signals.

The controlled light filters 5 are periodically brightened, in response to control signals, for a time equal to a duration t_p (FIG. 2) of brightening pulses Trl, or are periodically obscured for a time equal to a duration t₀ of attenuation pulses following one another with a period T. Transparency Tr of the light filters 5 varies pulsewise from a minimum value Tr_min at the beginning of pulse Trl to a maximum value Tr_ιnaχ in the effective period of pulse Trl, than again to a minimum value Tr_m^_n upon termination of pulse Trl. The head-lamps 3 (FIG. 1) of the transport vehicle being driven emit light pulses having a duration T_u (FIG. 2) and being synchronous with pulses Trl brightening the light filters 5 (FIG. 1), while the frequency of the light pulses emitted by the head¬ lamps 3 exceeds ten pulses per second. Once the total luminous flux φ = CD _j + φ has been transmitted through the light filters 5, its intensity J is periodically reduced due to a pulsewise variation of transparency Tr of the light filters 5, thus assuming a minimum value J _m__n (FIG. 2) and a maximum one J _max-

It is common knowledge that apparent brightness of any light source, pulsed one inclusive, is determined by a biochemical reaction occuring in the eye retina and depends on the number of photons

(light quanta) incident on the eye retina for the time of said reaction (0.1-0.2 s) (cf. the textbook "Light-engineering pulsed units" by G.X. Senilov, Energiya PH, Moscow, 1979, p. 6 (in

Russian) . Proceeding from the fact it is evident that at a repetition frequencv F = -^- of the light pulses equal to at least

T ten pulses per second, apparent brightness of a pulsed light source looked at through the controlled light filters 5 depends on the mean intensitv J of the transmitted luminous flux having intensitv

, r

For square pulses:

ntin, ^{( )}

^2 ⁼ ' ^'^IL (32ni(_x ^~ U2rιvLn) d∑niϋ (5) Proceeding from that

u^ ^ Zzax (4)

TT = ^{H έ 1 (}5⁾ it is obvious that the following inequality holds true at all times

5₂ < ^ (6) that is, the controlled light filter 5 attenuates the incident luminous flux φ having intensity J . It ensues from expressions (2) and (3) that while controlling duration t_p (FIG. 3) of brightening pulses Trl or repetition frequency F (FIG. 4), one can change the value of j 2 and hence the brightness of the external light sources 2 seen by the driver of the driven transport vehicle, e.g., the brightness of the sun or of the lighting unit of the oncoming transport vehicle. Thus, the brightness of the head-lamps 3 of the vehicle seen by the driver remains virtually unaffected, while the brightness of the lighting units 2 of the oncoming transport vehicle is reduced in accordance with expression (2) .

When the oncoming transport vehicle is equipped with pulsed light sources that generate luminous flux φ as a sequence of light pulses having intensity (FIG. 5), the periods of transmitting luminous flux Φ acting on the driver's sight, i.e., pulses Trl of brightening the light filters 5 (FIG. 1) are time-displaced with respect to light pulses generated by the external light sources 2 by a time interval t_c so that the brightening pulse are brought out of synchronism with the pulses of luminous flux ^ . Luminous flux <_, 3 generated by the head-lamps 3 of the vehicle remains virtually unaffected. The pulses of luminous flux φ 4 coincide with minimum translucency Tr_mj__n of the controlled light filters 5 and are therefore attenuated. When the value of Tr_{m n} is expressed in fractions of a complete transparency adopted to be unity, the attenuated luminous flux is as follows:

^J4 = J 4 • Tr_min . (7)

When the proposed method is put in a common practice, it is expedient to make use of an externally applied radio signal RI (FIG. 6) against which are synchronized the periods or transmission or attenuation of the luminous fluxes of a group of oncoming transport vehicles, that is, pulses Trl of brightening the light filters 5 by, e.g., inserting a time delay t-_j for a particular transport vehicle, said time delay being between the radio signal and the brightening pulse Trl. Used as such radio signals RI may be vertical pulses of a radio-frequency television signal.

In one of the embodiments of the present method, it is expedient that reduction of the intensity of luminous flux φ perceived by the driver's eyes 1 (FIG. 7) be performed nonuniformly within the angle -Ω. ^ of the driver's visual field so as to increase it in the solid angle d. 2 which confines the external light source 2, e.g. the sun. In this case the controlled light filter 5 is subdivided into portions 7 and 8 brightened by pulses TrL and Trl2 (FIG. 8) having different duration t ^ and t_p2_» respectively, or having different repetition frequency F^ _ 1 and F2= 1 . The

^■_ ^τ2 portions of the light filters 5, e.g., the portions 7, which protect the eyes 1 of the driver of the driven transport vehicle against a direct effect of the light radiation emitted by the bright light sources 2, are brightened by shorter (t_p^ < t_p7) brightening pulses Trl^, or by such pulses passing at a lower frequency (F^ FT) compared with pulses Trl2 that brighten the portion 8 of the controlled light filters 5.

Such a method for a nonuniform reduction of the intensity of luminous flux φ makes it possible to selectively diminish the apparent brightness of the brightest light sources 2 having low visible angular measures.

A device is proposed for carrying the afore-described method into effect, said device comprising the controlled light filters 5 (FIG. 10) which may be made as, e.g., liquid-crystal structures, or be shaped as spectacles, or else as light-protective eyewears with controlled transparency Tr. The light filters 5 are connected to the generator 6 of control pulses and are located on the driven transport vehicle across the path of luminous flux <φ perceived by the eyes of the driver of said transport vehicle. The generator 6 of control signals may be in fact an electric pulse generator with controlled duration t_t and frequency F of said pulses.

The liehting units, e.g., the head-lamps 3 of the driven transport vehicle comprise pulsed light sources connected to the controlled light filters through a timing unit 9 in the capacity of which use may be made of a generator of control electric pulses. In order to lock in brightening pulses t_p with light pulses I emitted by the external light source 2, e.g., the lighting units of the oncoming transport vehicle, as well as for adjusting the parameters of control signals acting on the controlled light filters 5, the device comprises additionally a detector of external light signals appearing as a photodetector 10, or a detector 11 or radio signals with an antenna 12 and connected to the generator 6 of control signals.

The controlled light filters 5 (FIG. 11) may appear as mosaic structures constituted by elementary light filters 13. Each of the mosaic structures consists of at least two elementary light filters 13, and the generator 6 of control signals is connected thereto through switching devices 14 controlled by an optical coordinate system 15.

Pulsed light sources of the lighting units 3 of the driven transport vehicle may be shaped as gaseous-discharge flash lamps 16 which may have two independent spatially displaced gas-discharge gaps 17 and 18 forming luminous fluxes 19 and 20 of the dim and distance light, respectively.

To ensure against dazzling of the driver of the transport vehicle being driven with the light emitted by lighting units 21 of the transport vehicles running behind, the device may be provided with rear-view mirrors 22 at the surface of which the controlled light filters 5 are located.

Thus, the proposed method and device for forming luminous fluxes acting on the organ of sight of the driver of a driven transport vehicle are capable of reducing a possibility of dazzling the driver with the external light source 2 and are therefore applicable for any transport vehicle.

Claims

1. A method for forming luminous fluxes acting on the organ of sight of a transport vehicle driver, consisting in that the intensity (J) of the luminous flux (φ) perceived by the driver's eyes and composed of the luminous fluxes (Φ , Φ_j), emitted by lighting units (3) of the transport vehicle being driven and by external light sources (2) , is periodically reduced before the luminous flux gets incident on driver's eyes (1) by alternating the periods (t_p, t_Q) of transmission and attenuation of the luminous flux (φ*) acting on the driver's sight, CHARACTERIZED in that the luminous flux ( φ 2) emitted by the lighting units (3) of the transport vehicle being driven is formed as a sequence of light pulses (I3) synchronous with the periods (t_p) of transmission of the luminous flux (<φ) , the frequency (F) of said light pulses (I3) exceeding ten pulses per second.

2. A method for forming luminous fluxes acting on the organ of sight of a transport vehicle driver according to Claim 1 , CHARACTERIZED in that, with the luminous flux ( _j) emitted by the external light sources (2) as a sequence of light pulses (I ) , the periods (t_p) of transmission of the luminous flux (&) acting on the driver's sight are time-displaced with respect to the light pulses (I ) emitted by the external light sources (2) .

3. A method for forming luminous fluxes acting on the organ of sight of a transport vehicle driver according to Claim 1 , CHARACTERIZED in that the intensity (j ) of the luminous flux (4) perceived by the driver's eyes is reduced nonuniformly within the angle ( -^~-- ) of the driver's visual field so as to reduce the intensity ( J 2) of the luminous flux within the solid angles ( 2-* that confine the external light sources (2) .

4. A method for forming luminous fluxes acting on the organ of sight of a transport vehicle driver according to Claim 1 , CHARACTERIZED in that use is made of an externally applied radio signal (RI) against which the periods (t_p, t₀) of transmission or attenuation of the luminous fluxes of a group of oncoming transport vehicles are brought in synchronism.

5. A device for forming luminous fluxes acting on the organ of sight of a transport vehicle driver, comprising the lighting units (3) situated on the transport vehicle being driven, controlled light filters (5) with a variable transparency (Tr) aimed at reducing the intensity ( J 2) °f the luminous flux (Φ) perceived by the driver's eyes (1) and situated on the transport vehicle being driven, a generator (6) of control signals which is electrically connected to the light filters (5) , CHARACTERIZED in that at least one of the lighting units (3) appears as a pulsed light source electrically connected to the generator (6) of control signals.

6. A device for forming luminous fluxes acting on the organ of sight of a transport vehicle driver according to Claim 5, CHARACTERIZED in that it additionally comprises a detector (10) of light signals from other transport vehicles, which is connected to the generator (6) of control signals.

7. A device for forming luminous fluxes acting on the organ of sight of a transport vehicle driver according to Claim 5, CAHRACTERIZED in that the controlled light filters (5) appear as mosaic structures constituted by elementary light filters (13).

8. A device for forming luminous fluxes acting on the organ of sight of a transport vehicle driver according to Claim 7, CHARACTERIZED in that it comprises a coordinate system (15) electrically connected to each of the elementary light filter (13).

9. A device for forming luminous fluxes acting on the organ of sight of a transport vehicle driver according to Claim 5 , CHARACTERIZED in that it additionally comprises a detector (11) of radiosignals (RI) located on the transport vehicle being driven and connected to the generator (6) of control signals.

10. A device for forming luminous fluxes acting on the organ of sight of a transport vehicle driver, according to Claim 5, CHARACTERIZED in that used as a pulsed light source is gaseous- discharge flash lamp (16) .