Headlamp for vehicle

Provided is a headlamp for a vehicle, including: a light source producing light; an optical unit provided in front of the light source, and producing a high beam or a low beam by partially blocking or not blocking the light emitted from the light source; and a micro-lens array provided in front of the optical unit and diffusing the light having passed through the optical unit, wherein the micro-lens array includes: a light incident plate having a number of first microlenses on a light incident surface facing the optical unit, the first microlenses refracting the light having passed through the optical unit forward; and a light exit plate having a number of second microlenses on a light exit surface opposing the light incident surface, the second microlenses diffusing the light having passed through the first microlenses, and the first microlenses and the second microlenses have different shapes.

CROSS-REFERENCE TO RELATED APPLICATION

This application is based on and claims the benefit of priority to Korean Patent Application No. 10-2019-0175574, filed on Dec. 26, 2019, in the Korean Intellectual Property Office, the disclosure of which is incorporated herein in its entirety by reference.

TECHNICAL FIELD

The present disclosure relates to a headlamp for a vehicle, to which a micro-lens array is applied.

BACKGROUND

In general, vehicle headlamps are used for: (i) providing a light function in order to view objects; and (ii) providing signals, warnings, and decorations to allow a driver to inform other vehicles or other road users of his or her driving states.

Meanwhile, a vehicle headlamp with a light function includes a light source producing and emitting light, a lens refracting the light emitted from the light source to illuminate the road ahead, a shield forming a high beam or a low beam by blocking part of the light emitted from the light source, and an actuator changing the position of the shield.

However, the aforementioned vehicle headlamp has a limitation in light diffusion, thus making it difficult to achieve a wider angle of visibility.

RELATED ART DOCUMENT

SUMMARY

An aspect of the present disclosure provides a headlamp for a vehicle, capable of significantly improving the diffusion of light by applying a micro-lens array thereto, thereby achieving a wider angle of visibility.

According to an aspect of the present disclosure, a headlamp for a vehicle may include: a light source producing light; an optical unit provided in front of the light source, and producing a high beam or a low beam by partially blocking or not blocking the light emitted from the light source; and a micro-lens array provided in front of the optical unit and diffusing the light having passed through the optical unit, wherein the micro-lens array may include: a light incident plate having a number of first microlenses on a light incident surface facing the optical unit, the first microlenses refracting the light having passed through the optical unit forward; and a light exit plate having a number of second microlenses on a light exit surface opposing the light incident surface, the second microlenses diffusing the light having passed through the first microlenses, and the first microlenses and the second microlenses may have different shapes.

The first microlens may have a rotationally symmetric structure, and the second microlens may have an asymmetric structure in which a vertical cross-section and a horizontal cross-section have different curvatures.

The first microlens may have an asymmetric structure in which a vertical cross-section and a horizontal cross-section have different curvatures, and the second microlens may have a rotationally symmetric structure.

The second microlens may have a connection surface connected to the light exit surface, the connection surface being circular, the vertical cross-section may have a semicircular shape with a predetermined curvature so that vertical light having passed through the first microlens may be refracted forward, and the horizontal cross-section may have a rectangular shape so that lateral light having passed through the first microlens may be diffused laterally.

A tip portion of the second microlens may be concavely recessed when viewed from the horizontal cross-section.

The first microlens may have a connection surface connected to the light exit surface, the connection surface being circular, the vertical cross-section may have a semicircular shape with a predetermined curvature so that vertical light having passed through the optical unit may be refracted forward, and the horizontal cross-section may have a rectangular shape so that lateral light having passed through the optical unit may be diffused laterally.

The first microlenses provided on the light incident plate and the second microlenses provided on the light exit plate may have the same array structure, or different array structures.

The first microlenses may be spaced apart from each other so as not to contact each other, and the second microlenses may be spaced apart from each other so as not to contact each other.

The micro-lens array may further include: a pair of transparent plates provided between the light incident plate and the light exit plate; and a transparent shield provided between the pair of transparent plates.

According to another aspect of the present disclosure, a headlamp for a vehicle may include: a light source producing light; an optical unit provided in front of the light source, and producing a high beam or a low beam by partially blocking or not blocking the light emitted from the light source; and a micro-lens array provided in front of the optical unit, and diffusing the light having passed through the optical unit, wherein the micro-lens array may include: a light incident plate having a number of first microlenses on a light incident surface facing the optical unit, the first microlenses diffusing the light having passed through the optical unit; and a light exit plate having a number of second microlenses on a light exit surface opposing the light incident surface, the second microlenses diffusing the light having passed through the first microlenses, and the first microlenses and the second microlenses may have the same shape.

The first microlens and the second microlens may have an asymmetric structure in which a vertical cross-section and a horizontal cross-section have different curvatures.

The first microlens may have a connection surface connected to the light incident surface, the connection surface being circular, the vertical cross-section of the first microlens may have a semicircular shape with a predetermined curvature so that vertical light having passed through the optical unit may be refracted forward, and the horizontal cross-section of the first microlens may have a rectangular shape so that lateral light having passed through the optical unit may be diffused laterally. The second microlens may have a connection surface connected to the light exit surface, the connection surface being circular, the vertical cross-section of the second microlens may have a semicircular shape with a predetermined curvature so that vertical light having passed through the first microlens may be refracted forward, and the horizontal cross-section of the second microlens may have a rectangular shape so that lateral light having passed through the first microlens may be diffused laterally.

The first microlenses and the second microlenses may have the same size.

A tip portion of the second microlens may be concavely recessed when viewed from the horizontal cross-section.

The micro-lens array may further include: a pair of transparent plates provided between the light incident plate and the light exit plate; and a transparent shield provided between the pair of transparent plates.

DETAILED DESCRIPTION

Hereinafter, exemplary embodiments of the present disclosure will be described in detail with reference to the accompanying drawings so that those skilled in the art can easily carry out the invention. The invention may, however, be embodied in many different forms and should not be construed as being limited to the embodiments set forth herein. In addition, a detailed description of well-known techniques and constructions will be ruled out in order not to unnecessarily obscure the gist of the present disclosure, and like reference numerals will denote like elements throughout the specification.

[Headlamp for Vehicle According to First Exemplary Embodiment of Present Disclosure]

A headlamp100for a vehicle according to a first exemplary embodiment of the present disclosure may include, as illustrated inFIGS. 1 to 8, a light source110producing light, an optical unit120producing a high beam or a low beam by partially blocking or not blocking the light emitted from the light source110, and a micro-lens array130diffusing the light having passed through the optical unit120.

Light Source

The light source110may be a device that produces light, and a light emitting diode (LED) lamp may be applied thereto. The light source110may emit the light to the optical unit120.

Optical Unit

The optical unit120may be provided to form a high beam or a low beam. The optical unit120may be provided in front of the light source110, and produce the high beam or the low beam using the light emitted from the light source110. For example, the optical unit120may produce the high beam or the low beam by partially blocking or not blocking the light of the light source110.

The micro-lens array130may be provided in front of the optical unit120, and cause the light having passed through the optical unit120to spread in all directions, especially, laterally.

That is, the micro-lens array130may include a light incident plate131having a number of first microlenses131aon a light incident surface facing the optical unit120, the first microlenses131arefracting the light having passed through the optical unit120forward (that is, toward a light exit plate132), and the light exit plate132having a number of second microlenses132aon a light exit surface opposing the light incident surface, the second microlenses132adiffusing the light having passed through the first microlenses131ain all directions.

Here, the first microlens131aand the second microlens132amay have different shapes. In particular, the second microlens132amay be shaped to increase a diffusion angle of light.

For example, the first microlens131amay have a rotationally symmetric structure, and the second microlens132amay have an asymmetric structure in which a vertical cross-section and a horizontal cross-section are different from each other.

That is, the first microlens131amay have a hemispherical shape, and refract the light that has passed through the optical unit120so as to focus the light on a point (focal point) in front of the first microlens131a.

The second microlens132amay have a connection surface connected to the light exit surface, and the connection surface may be circular. The vertical cross-section of the second microlens132amay have a semicircular shape with a predetermined curvature so that vertical light having passed through the first microlens131amay be refracted forward (that is, toward the second microlens), and the horizontal cross-section of the second microlens132amay have a rectangular shape so that lateral light having passed through the first microlens131amay be diffused laterally.

The second microlens132amay have a circular shape when viewed from the rear, have a hemispherical shape when viewed from the side, and have a rectangular shape when viewed from the top. A rear portion (connection surface) of the second microlens132aattached to the light exit plate132and a rear portion (connection surface) of the first microlens131aattached to the light incident plate131may have the same lateral width as illustrated inFIG. 6. However, a lateral width of a tip portion of the second microlens132amay be greater than that of the first microlens131a, and accordingly, the second microlens132amay allow the light having passed through the first microlens131ato be greatly diffused laterally. As a result, a diffusion angle of light and an angle of visibility may be significantly increased.

The micro-lens array130having the aforementioned structure may increase the diffusion angle of light, and ensure a wider angle of visibility.

Meanwhile, the light incident plate131and the light exit plate132may be made of a transparent synthetic resin material, thereby preventing damage due to external and internal impacts, and improving manufacturing efficiency.

The tip portion of the second microlens132amay be formed as a concavely recessed, curved surface132a-1when viewed from the horizontal cross-section. Thus, the light having passed through the light incident plate131may be refracted so as to be greatly diffused laterally, and consequently the diffusion angle may be increased.

Meanwhile, the plurality of first microlenses131aprovided on the light incident plate131and the plurality of second microlenses132aprovided on the light exit plate132may have the same array structure. That is, the plurality of first microlenses131aand the plurality of second microlenses132amay correspond to each other. Accordingly, as the light having passed through the plurality of first microlenses131adirectly enters the plurality of second microlenses132a, the light may be evenly diffused. As a result, the brightness of light emitted by the headlamp may be evenly regulated.

Alternatively, the plurality of first microlenses131aprovided on the light incident plate131and the plurality of second microlenses132aprovided on the light exit plate132may have different array structures. That is, the plurality of first microlenses131aand the plurality of second microlenses132amay not correspond to each other. Accordingly, as the light having passed through the plurality of first microlenses131aspreads out over the plurality of second microlenses132a, it may be widely diffused. Thus, the headlamp may provide improved illumination by casting the light onto the area that has not been illuminated.

Meanwhile, the plurality of first microlenses131aprovided on the light incident plate131may be spaced apart from each other so as not to contact each other. In particular, the plurality of first microlenses131amay be spaced apart from each other by 0.2-2 mm. In addition, the plurality of second microlenses132aprovided on the light exit plate132may be spaced apart from each other so as not to contact each other. In particular, the plurality of second microlenses132amay be spaced apart from each other by 0.2-2 mm. Thus, easiness of manufacturing may be achieved, and the irregular diffusion of light may be prevented.

The micro-lens array130may further include a pair of transparent plates133and134provided between the light incident plate131and the light exit plate132, and a transparent shield135provided between the pair of transparent plates133and134. That is, the pair of transparent plates133and134may increase strength, and the transparent shield135may allow the pair of transparent plates133and134to be firmly attached.

Here, the pair of transparent plates and the transparent shield may have the same size as that of the light incident plate and the light exit plate.

In addition, the pair of transparent plates133and134may be formed of tempered glass to increase transparency, and the transparent shield135may include chromium.

Thus, as illustrated inFIGS. 7 and 8, the headlamp100for a vehicle according to the first exemplary embodiment of the present disclosure may include the micro-lens array130so that the vertical light may be refracted forward to prevent unnecessary light diffusion, and the lateral light may be greatly diffused laterally to ensure a wider angle of visibility.

EXPERIMENTAL EXAMPLES

Comparative Example

The diffusion (spread) of light was simulated using a headlamp according to the related art, the headlamp including: a light source; an optical unit; and a micro-lens array in which first microlenses having a rotationally symmetric structure are provided on both surfaces of the micro-lens array. The simulation results were obtained as illustrated inFIG. 9.

Inventive Example

The diffusion (spread) of light was simulated using a headlamp according to an exemplary embodiment of the present disclosure, the headlamp including: a light source; an optical unit; and a micro-lens array in which first and second microlenses are provided. The simulation results were obtained as illustrated inFIG. 10.

Experimental Results

Referring toFIG. 9, the light in the comparative example may be diffused vertically and laterally in a square form. That is, it can be seen that the diffusion of light hardly occurs in the comparative example.

Referring toFIG. 10, the light in the inventive example may be diffused vertically similar to the comparative example, and may be greatly diffused laterally compared to the comparative example.

Thus, it can be seen that the headlamp according to the exemplary embodiment of the present disclosure may provide improved lateral illumination, compared to the related art headlamp.

Hereinafter, in describing the following other embodiments of the present disclosure, the elements having the same functions as in the previous embodiment will be designated by the same reference numerals, and a detailed description thereof will be omitted.

[Headlamp for Vehicle According to Second Exemplary Embodiment of Present Disclosure]

As illustrated inFIG. 11, the headlamp100according to the second exemplary embodiment of the present disclosure may include the light source110producing light, the optical unit120producing a high beam or a low beam using the light of the light source110, and the micro-lens array130diffusing the light having passed through the optical unit120.

The micro-lens array130may include the light incident plate131on which a number of first microlenses131bare provided, and the light exit plate132on which a number of second microlenses132bare provided. The first microlens131band the second microlens132bmay have different shapes. In particular, the first microlens131bmay be shaped to increase a diffusion angle of light.

For example, the first microlens131bmay have an asymmetric structure in which a vertical cross-section and a horizontal cross-section have different curvatures, and the second microlens132bmay have a rotationally symmetric structure.

Meanwhile, the first microlens131bin the second exemplary embodiment may have the same structure as that of the second microlens132ain the first exemplary embodiment, and a detailed description thereof will be omitted.

Thus, the headlamp100for a vehicle according to the second exemplary embodiment of the present disclosure may significantly diffuse the light laterally through the first microlenses131b, and refract the diffused light forward through the second microlenses132b, thereby increasing the diffusion angle of light. That is, the headlamp100for a vehicle according to the second exemplary embodiment may have the smaller diffusion angle of light than that of the headlamp100according to the first exemplary embodiment, but may increase the diffusion angle of light compared to the comparative example.

[Headlamp for Vehicle According to Third Exemplary Embodiment of Present Disclosure]

As illustrated inFIG. 12, the headlamp100according to the third exemplary embodiment of the present disclosure may include the light source110producing light, the optical unit120producing a high beam or a low beam using the light of the light source110, and the micro-lens array130diffusing the light having passed through the optical unit120.

The micro-lens array130may include the light incident plate131having a number of first microlenses131con the light incident surface facing the optical unit120, the first microlenses131crefracting the light having passed through the optical unit120forward, and the light exit plate132having a number of second microlenses132con the light exit surface opposing the light incident surface, the second microlenses132cdiffusing the light having passed through the first microlenses131cin all directions.

Here, the first microlens131cand the second microlens132cmay have the same shapes. That is, the first microlens131cand the second microlens132cmay have an asymmetric structure in which a vertical cross-section and a horizontal cross-section have different curvatures.

For example, the first microlens131cmay have a connection surface connected to the light incident surface, and the connection surface may be circular. The vertical cross-section of the first microlens131cmay have a semicircular shape with a predetermined curvature so that vertical light having passed through the optical unit120may be refracted forward, and the horizontal cross-section of the first microlens131cmay have a rectangular shape so that lateral light having passed through the optical unit120may be diffused laterally. The second microlens132cmay have a connection surface connected to the light exit surface, and the connection surface may be circular. The vertical cross-section of the second microlens132cmay have a semicircular shape with a predetermined curvature so that vertical light having passed through the first microlens131cmay be refracted forward, and the horizontal cross-section of the second microlens132cmay have a rectangular shape so that lateral light having passed through the first microlens131cmay be diffused laterally.

Thus, the headlamp100for a vehicle according to the third exemplary embodiment of the present disclosure may significantly increase a diffusion angle of light, thereby significantly increasing an angle of visibility.

Meanwhile, the first microlens131cand the second microlens132cmay have the same size. Accordingly, as the light having passed through the first microlenses131cdirectly enters the second microlenses132c, the diffusion angle of light may be increased.

A tip portion of the second microlens132cmay be concavely recessed when viewed from the horizontal cross-section. Thus, it may diffuse the light more effectively.

Meanwhile, the micro-lens array130may further include a pair of transparent plates provided between the light incident plate and the light exit plate, and a transparent shield provided between the pair of transparent plates, thereby increasing strength.

As set forth above, by applying the micro-lens array to the headlamp according to exemplary embodiments of the present disclosure, the diffusion angle of light may be significantly increased, and thus a wider angle of visibility may be achieved.