Bending light device for vehicles

A bending light device for a vehicle diffracting light emitted from a light source and deflecting the light at a desired angle and in a desired direction may include an ultrasonic light deflector configured to diffract light incident thereon in a selected direction by emitting an ultrasonic beam to the incident light, a light reflection unit configured to reflect light emitted from a light source to the ultrasonic light deflector, a projection lens configured to project light incident thereon after passing through the ultrasonic light deflector to radiate the light outside, and a converging lens arranged between the ultrasonic light deflector and the projection lens and configured to converge the light having passed through the ultrasonic light deflector on the projection lens.

CROSS-REFERENCE TO RELATED APPLICATION

The present application claims priority to Korean Patent Application No. 10-2015-0090847 filed on Jun. 26, 2015, the entire contents of which is incorporated herein for all purposes by this reference.

BACKGROUND

Field of the Invention

The present disclosure relates to a bending light device for vehicles. More particularly, it relates to a bending light device for vehicles capable of diffracting light emitted from a light source and deflecting the light at a desired angle and in a desired direction.

Description of Related Art

In general, a headlamp is mounted to the front side of a vehicle in order to ensure safe driving by efficiently illuminating the road in front of the vehicle at night.

A conventional headlamp is typically secured to a lamp housing, and merely radiates light in a direction parallel to the centerline of the vehicle. When the vehicle travels on a curved road, the conventional headlamp merely provides illumination directly in front of the vehicle. Thus, the driver cannot properly secure clear vision when driving on a curved road.

In order to address this situation, there has recently been developed a headlamp equipped with a bending light device, in which the illumination angle is automatically controlled in the left or right direction depending on the travelling direction of the vehicle. As such, a headlight-related technology, an adaptive front lighting system (AFLS) has been developed, in which the headlights move in the left or right direction depending on the direction in which the driver turns the steering wheel, thereby illuminating the road in the travelling direction of the vehicle and securing proper vision for the driver at night.

FIG. 1is a front view illustrating a conventional bending light device,FIG. 2is a sectional view taken along line A-A inFIG. 1, andFIG. 3is a sectional view taken along line B-B inFIG. 1.

Referring toFIGS. 1 through 3, a conventional bending light device is constituted such that an optical module1is swiveled in the left or right direction about a rotating shaft6by a motor5of an actuator. After the optical module1is swiveled in one direction, light from a light source2is reflected from a light reflection unit3, and is projected through a projection lens4to illuminate the road in the direction in which the vehicle is travelling.

However, in the conventional bending light device, because the optical module1is swiveled about the rotating shaft6by the motor5, malfunction due to mechanical defects and flickering due to inertia of the motor may occur, and the light may not be precisely controlled.

For example, interference between components including wires may occur due to the rotation of the optical module by the motor, and rotational malfunction of the optical module may occur due to damage to the rotating shaft (driving shaft), which may be caused by external shocks or vibration.

BRIEF SUMMARY

Various aspects of the present invention are directed to providing a bending light device for vehicles capable of diffracting light emitted from a light source of an optical module using an ultrasonic beam and deflecting the light in a desired direction.

In one aspect, the present invention provides a bending light device for vehicles including an ultrasonic light deflector configured to diffract light incident thereon in any one selected direction by emitting an ultrasonic beam to the incident light, a light reflection unit configured to reflect light emitted from a light source to the ultrasonic light deflector, a projection lens configured to project light incident thereon after passing through the ultrasonic light deflector in order to radiate the light outside, and a converging lens arranged between the ultrasonic light deflector and the projection lens and configured to converge the light having passed through the ultrasonic light deflector on the projection lens.

In an exemplary embodiment, the ultrasonic light deflector may include a first light deflection unit capable of diffracting light incident thereon in one of left and right directions, and a second light deflection unit capable of diffracting the light incident thereon in the other direction, thereby deflecting the light incident thereon in any one direction selected from the left and right directions.

In another exemplary embodiment, the bending light device may further include a headlamp control unit configured to control a frequency of the ultrasonic beam emitted from the ultrasonic light deflector, based on an angle at which the light incident on the ultrasonic light deflector is intended to be diffracted.

In still another exemplary embodiment, the headlamp control unit may selectively activate any one of the first light deflection unit and the second light deflection unit depending on a direction in which the light incident on the ultrasonic light deflector is intended to be diffracted, and may control a frequency of the ultrasonic beam emitted from the light deflection unit, selected based on an angle at which the light incident on the ultrasonic light deflector is intended to be diffracted.

In yet another exemplary embodiment, the bending light device may further include a bending light control unit configured to decide a deflection angle at which the light incident on the ultrasonic light deflector is to be diffracted and to transmit the decided deflection angle to the headlamp control unit, and the headlamp control unit may generate an acoustic modulation signal based on the deflection angle information transmitted thereto and may transmit the acoustic modulation signal to the ultrasonic light deflector, so that the ultrasonic light deflector emits an ultrasonic beam having a predetermined frequency.

Other aspects and exemplary embodiments of the invention are discussed infra.

DETAILED DESCRIPTION

Hereinafter, the embodiment of the present invention will be described in detail with reference to the accompanying drawings to allow those skilled in the art to easily implement the present invention.

The present invention relates to a bending light device capable of realizing bending light (or diffracted light) using an ultrasonic light deflector, in which light emitted from a light source and incident on an ultrasonic light deflector is diffracted and deflected in a desired direction by an ultrasonic beam, thereby enhancing visibility to secure safety while driving at night, preventing malfunctions due to mechanical defects and flickering due to inertia of the motor, and improving response by adjustment of a deflection angle through an electroacoustic mechanism.

Referring toFIGS. 4 through 6, a bending light device according to the present invention is disposed in a headlamp (headlight) and, more particularly, is arranged in front of a light source12of an optical module10that constitutes the headlamp. The bending light device includes an ultrasonic light deflector110disposed in front of the light source12, a converging lens120, and a projection lens130.

The optical module10of the headlamp is constituted such that light emitted from the light source12is projected outside the optical module10through the projection lens130in order to illuminate the road.

The ultrasonic light deflector110, the converging lens120and the projection lens130are securely supported on a base16, to which the light source12and a light reflection unit14of the optical module10are mounted.

The ultrasonic light deflector110serves to deflect a light beam using an acousto-optic effect, and is arranged in front of the light source12. If the light emitted from the light source12is reflected from the light reflection unit14and is incident on the ultrasonic light deflector110, the ultrasonic light deflector110emits an ultrasonic beam according to the required deflection conditions in a direction perpendicular to the incident light (the light incident on the ultrasonic light deflector), thereby diffracting the incident light and consequently deflecting the incident light in the desired direction.

The light incident on the ultrasonic light deflector110is projected at a predetermined deflection angle depending on the change in the wavelength of the ultrasonic beam emitted by the ultrasonic light deflector110, and is diffracted with respect to the angle of incidence on the ultrasonic light deflector110, and accordingly is radiated in a deflected pattern in a left or right direction.

The light source12is arranged so as to emit light toward the light reflection unit14. The light reflection unit14is arranged behind the light source12, and reflects the light from the light source12toward the ultrasonic light deflector110.

The converging lens120is arranged between the ultrasonic light deflector110and the projection lens130. The converging lens120serves to control the phase of the light that has passed through the ultrasonic light deflector110. In detail, the converging lens120modulates and controls the phase of the light diffracted by the ultrasonic light deflector110so that the light converges on the projection lens130. Accordingly, the light that is diffracted in an undesired direction by the ultrasonic light deflector110converges on the projection lens130.

The converging lens120may be embodied as a kind of multifocal convex lens, which is configured to make light that is incident in a multifocal pattern converge on one point. As shown inFIG. 7, the converging lens120focuses the light, which is diffracted and deflected upward or downward by the ultrasonic light deflector110, on the projection lens130, and accordingly modulates the phase difference of the light due to diffraction in an undesired up or down direction, thereby adjusting the illumination difference in a light distribution area.

The projection lens130maintains the proceeding direction and pattern of the light incident thereon, after passing through the ultrasonic light deflector110and the converging lens120, and projects the light outside. The light projected through the projection lens130illuminates the area in front of the vehicle.

In order to selectively deflect the light radiated in front of the vehicle from the headlamp in the left or right direction, the ultrasonic light deflector110is configured to emit the ultrasonic beam in any one direction selected from the left and right directions.

As is well known in the art, a general ultrasonic light deflector is a device that deflects a light beam using an acousto-optic effect, and includes an electroacoustic transducer for emitting an ultrasonic beam and an acoustic absorber for receiving the ultrasonic beam emitted from the electroacoustic transducer. The ultrasonic beam emitted from the electroacoustic transducer disposed at one side diffracts and deflects the light incident on the ultrasonic light deflector, and the ultrasonic beam, after diffracting the incident light, is absorbed in the acoustic absorber disposed at the opposite side.

FIG. 8is a schematic constitutional view illustrating the ultrasonic light deflector110according to an embodiment of the present invention.

As shown inFIG. 8, in order to ensure bidirectional emission, the ultrasonic light deflector110includes a first light deflection unit111capable of diffracting the incident light in one of left and right directions, and a second light deflection unit112capable of diffracting the incident light in the other direction. As a result, the ultrasonic light deflector110can deflect the incident light in any one direction selected from the left and right directions.

The first light deflection unit111and the second light deflection unit112are stacked (arranged) parallel to and adjacent to each other.

The first light deflection unit111includes a first light incidence part113, through which the light reflected from the light reflection unit14is incident and passes, and a first light-emitting part114aand a first light receiving part114bwhich are arranged on left and right sides of the first light incidence part113. The second light deflection unit112includes a second light incidence part115, through which the light reflected from the light reflection unit14is incident and passes, and a second light-emitting part116aand a second light receiving part116bwhich are arranged on left and right sides of the second light incidence part115.

The first and second light-emitting parts114aand116aare configured to emit the ultrasonic beam having a predetermined frequency depending on the light deflection conditions, and the first and second light receiving parts114band116bare configured to receive the ultrasonic beam emitted from the first and second light-emitting parts114aand116a.

The first light-emitting part114aand the first light receiving part114bare arranged opposite to each other on left and right sides of the first light incidence part113, and the second light-emitting part116aand the second light receiving part116bare arranged opposite to each other on left and right sides of the second light incidence part115. The first light-emitting part114aand the second light receiving part116bare arranged parallel to each other on one of the left and right sides of the ultrasonic light deflector110, and the second light-emitting part116aand the first light receiving part114bare arranged parallel to each other on the other side of the ultrasonic light deflector110.

The ultrasonic light deflector110emits the ultrasonic beam having a predetermined frequency based on an emission signal transmitted from a headlamp control unit140(refer toFIG. 12), and diffracts the incident light.

The headlamp control unit transmits a modulation signal to any one of the first light deflection unit111and the second light deflection unit112depending on the direction in which the light incident on the ultrasonic light deflector110is intended to be diffracted, and selectively activates the same. At this time, depending on the angle (deflection angle) at which the light incident on the ultrasonic light deflector110is intended to be diffracted, the headlamp control unit controls the frequency of the ultrasonic beam emitted from the ultrasonic light deflector110(particularly, the light-emitting part of the light deflection unit, selected from the first light deflection unit and the second light deflection unit).

In this embodiment, the ultrasonic light deflector110is constituted such that the light deflection units are arranged parallel to each other, however, the constitution is not limited thereto. The ultrasonic light deflector110may have any constitution as long as it can deflect the incident light in any one direction selected from the left and right directions by emitting the ultrasonic beam in either the left or right direction.

As shown inFIG. 9, using the ultrasonic beam emitted from the ultrasonic light deflector110mounted in the headlamp, the bending light device allows the light incident on the light incidence parts (113,115) to pass through the ultrasonic light deflector without deflection while travelling straight, deflects the light radiated ahead of the vehicle from the headlamp in the left direction during a left turn, and deflects the light radiated ahead of the vehicle from the headlamp in the right direction during a right turn.

As a result, as shown inFIG. 10, since an obstacle located on a curved road comes into the light distribution area of the headlamp during the left or right turn, the driver can properly secure clear visibility of the area in front of the vehicle and obstacles in front, thereby ensuring driving safety. The area indicated by the dotted lines inFIG. 10is the light distribution area before deflecting the light radiated from the headlamp, and the area indicated by the solid lines is the light distribution area after deflecting the light radiated from the headlamp.

The ultrasonic light deflector110emits an ultrasonic beam having a predetermined frequency using an acoustic modulation signal transmitted from the headlamp control unit140(refer toFIG. 12). The ultrasonic beam is emitted from the light-emitting part114aor116a, and has a predetermined frequency and a predetermined wavelength depending on the angle (deflection angle) at which the light incident on the ultrasonic light deflector110is intended to be deflected.

If the headlamp control unit140receives the deflection angle information from a bending light control unit150(AFLS ECU, refer toFIG. 12), the headlamp control unit140generates an acoustic modulation signal based on the deflection angle information transmitted thereto, and transmits the acoustic modulation signal to the light-emitting part114aor116a. The light-emitting part114aor116acontrols the frequency and wavelength of the ultrasonic beam depending on the acoustic modulation signal transmitted thereto, and emits the ultrasonic beam.

At this time, the headlamp control unit140transmits the acoustic modulation signal to the light-emitting part (the first light-emitting part114aor the second light-emitting part116a) of the ultrasonic light deflector110selected depending on the direction in which the incident light is intended to be diffracted, and the light-emitting part (the first light-emitting part114aor the second light-emitting part116a) to which the acoustic modulation signal is transmitted emits the ultrasonic beam.

Accordingly, if the ultrasonic light deflector110receives the acoustic modulation signal, an ultrasonic beam having a predetermined frequency depending on the light deflection conditions is emitted into the light incidence part (the first light incidence part113or the second light incidence part115), thereby deflecting the light incident on the light incidence part113or115at a desired angle and in a desired direction.

A method of controlling the bending light device for vehicles according to the present invention constituted as above will now be described with reference toFIGS. 11 and 12.

Referring toFIGS. 11 and 12, if the operating conditions of the bending light device, i.e., the operating conditions of the ultrasonic light deflector110, are input, the bending light control unit (AFLS ECU)150decides the deflection angle at which the light incident on the light incidence part113or115is to be diffracted.

Depending on the operating conditions of the ultrasonic light deflector110, the bending light control unit (AFLS ECU)150decides whether to operate the ultrasonic light deflector110(i.e., whether to emit the ultrasonic beam) and the diffraction direction of the light incident on the light incidence part113or115, and transmits the decision to the headlamp control unit140. The bending light control unit (AFLS ECU)150also decides the deflection angle at which the light incident on the light incidence part113or115is to be diffracted, and transmits the decided deflection angle to the headlamp control unit140.

The operating conditions of the ultrasonic light deflector110include the steering angle of the steering wheel, the vehicle speed, and the like.

The bending light control unit (AFLS ECU)150decides the deflection angle based on the steering angle, vehicle speed, acceleration, braking and the like, and controls the light to be diffracted at the decided deflection angle through the ultrasonic light deflector110and to illuminate the area toward which the vehicle is going to travel.

Next, based on the deflection angle information transmitted from the bending light control unit (AFLS ECU)150, the headlamp control unit140controls the ultrasonic light deflector110to allow the light incident on the light incidence part113or115to be projected without diffraction or to be diffracted in any one direction selected from the left and right directions. Then, the headlamp control unit140generates the acoustic modulation signal depending on the decided deflection angle and transmits the same to the light-emitting part114aor116aof the ultrasonic light deflector110.

As described above, if the headlamp control unit140receives the deflection angle information from the bending light control unit (AFLS ECU)150, the headlamp control unit140generates the acoustic modulation signal based on the deflection angle information transmitted thereto, and transmits the acoustic modulation signal to the light-emitting part114aor116a. The light-emitting part114aor116acontrols the frequency and wavelength of the ultrasonic beam depending on the acoustic modulation signal transmitted thereto, and emits the ultrasonic beam.

At this time, the headlamp control unit140transmits the acoustic modulation signal to the light-emitting part114aor116aselected depending on the diffraction direction of the light incident on the ultrasonic light deflector110.

The ultrasonic beam emitted from the first light-emitting part114adeflects the incident light in one of left and right directions, and the ultrasonic beam emitted from the second light-emitting part116adeflects the incident light in the other direction.

After receiving the acoustic modulation signal, the light-emitting part114aor116aemits the ultrasonic beam, which has a predetermined frequency depending on the angle at which the incident light is intended to be deflected, in the direction perpendicular to the incident light, thereby diffracting the incident light at a predetermined angle and in a predetermined direction.

In order to determine whether the ultrasonic light deflector110is malfunctioning or not, the bending light control unit (AFLS ECU)150samples the amount of light incident on photo-sensors118mounted to left and right sides of an inner top portion of a projection lens holder132(refer toFIG. 5) and digitalizes the same.

The projection lens holder132functions so that the projection lens130having an aspherical lens type can be securely supported on the front end of the base16.

The bending light control unit (AFLS ECU)150determines whether the ultrasonic light deflector110has realized the deflection angle, based on the amount of light measured through the photo-sensors118. Upon determining that the ultrasonic light deflector110is malfunctioning, i.e., that the deflection angle is insufficient or excessive, the bending light control unit (AFLS ECU)150calculates a deflection angle correction value based on an error value (a lack or excess of the deflection angle), corrects the information of the pre-decided deflection angle, and transmits the corrected deflection angle information to the headlamp control unit140.

The headlamp control unit140regenerates an acoustic modulation signal based on the corrected deflection angle information and transmits the same to the ultrasonic light deflector110, thereby controlling the ultrasonic light deflector110to emit an ultrasonic beam having a corrected frequency.

In other words, based on the amount of light measured through the photo-sensors118, the bending light control unit (AFLS ECU)150detects the light that does not converge on the projection lens130but diverges outside the projection lens130, and accordingly determines whether the ultrasonic light deflector110is malfunctioning or not.

The bending light device for vehicles according to the present invention has the following advantages.

Since the deflection angle of the light incident on the ultrasonic light deflector is determined depending on the change in the wavelength of the ultrasonic beam emitted from the ultrasonic light deflector, the light can be diffracted at an angle different from the angle at which it is incident on the ultrasonic light deflector, and can be deflected in either the left or right direction.

Further, compared to a conventional bending light device, the present invention is optimized with a simple structure, from which a motor and other components associated therewith are omitted. Accordingly, noise due to mechanical operation and malfunction due to mechanical defects may be eliminated, and the weight of the device and the manufacturing cost may be reduced.

Furthermore, the bending light device according to the present invention may exhibit more responsive operation due to the adjustment of deflection through the electroacoustic mechanism using the ultrasonic light deflector, and the deflection may be precisely controlled by adjusting the acoustic wavelength in micro units.

While a conventional bending light device has a problem whereby rotational error occurs due to inertia of a motor because the light pattern is adjusted in the left or right direction by the operation of a motor, the bending light device according to the present invention can adjust the acoustic wavelength in micro units, thereby achieving precise adjustment of the light pattern.