Laser optical system for headlights

Abstract

A laser optical system for a headlight, comprising: a laser diode (10); a structure film (20) having a surface on which a microstructure (21) is formed to scatter a laser beam (L1) emitted from the laser diode (10) and to determine a width and a height of the beam (L1) in accordance with a desired shape; a reflective film (30) having a film opening (31) formed thereon for transmitting the laser beam (L2) which is scattered through the structural film (20); a phosphor film (40) formed in a film shape to respond to the laser beam (L2) passing through the reflective film (30) to emit white light (L3); and an aspherical lens (50) configured to direct the white light (L3) passing through the phosphor film (40) to a front region, wherein the laser diode (10) and the aspherical lens (50) are arranged in a line, characterized in that the laser optical system further comprises: a rear holder (60) in which the structural film (20) and the reflective film (30) are coupled to each other and face each other; a front holder (70) in which the phosphor film (40) is combined so that the phosphor film (40) is arranged in front of the reflective film (30); and a plurality of brackets (80) configured to interconnect the rear holder (60) and the front holder (70).

Description

BACKGROUND OF THE INVENTIONField of the invention

[0001] The present invention relates to a laser optical system for a headlamp; and more particularly, to a laser optical system for a headlamp which can increase optical efficiency by minimizing light loss and increase degrees of freedom for design by reducing the size of the optical system. Description of related technology

[0002] A headlight (headlamp) of a vehicle is a lamp that illuminates an area in front to ensure the front field of vision of a driver, and halogen, HID (high intensity discharge), or an LED diode was commonly used as the light source.

[0003] However, since halogen, HID, or LED diodes have high power consumption, their optical efficiency is reduced. In particular, since the overall size of an optical system consisting of a light source and a lens is large, the degree of freedom for design is limited, and the optical system becomes heavy.

[0004] Recently, the development of a headlight using a laser diode as a light source, which is environmentally friendly and has a long service life and high optical efficiency, has become a growing trend.

[0005] As in Fig. 1, a laser optical system for a headlight in the related art is configured to include a laser diode 1 that generates a laser beam of a blue wavelength band, a yellow phosphor 2 that responds to light emitted from the laser diode 1 to emit white light, a reflecting body 3 that reflects the white light emitted from the phosphor 2 to a front area, an aspherical lens 4 positioned in front of the reflecting body 3 to condense, disperse, and inject the white light reflected by the reflecting body 3 into the front area, and a shield 5 positioned between the reflecting body 3 and the aspherical lens 4 to realize a low beam.

[0006] However, according to the configuration of the laser optical system in the related art as described above, the light emitted from the laser diode 1 is incident on the phosphor 2 to be excited, and then is reflected by the reflecting body 3 to the front portion where the aspherical lens 4 is provided. Accordingly, since the front portion of the reflecting body 3 is opened to emit the white light, a light loss region A1 occurs in which the light emitted from the laser diode 1 is excited by the phosphor 2 and then emitted from the reflecting body 3, so that the light loss of the optical system is generally increased to cause the optical efficiency to be reduced.

[0007] That is, the structure in the related art is configured to use the reflecting body 3 for forward emission of the white light, and when the reflecting body 3 is used, the light loss area A1 in which the white light is emitted from the reflecting body 3 occurs, and thus the light loss of the optical system is generally increased to cause the optical efficiency to decrease.

[0008] Furthermore, since the reflecting body 3 having a large volume is used, the weight of the optical system becomes heavy and the size of the optical system increases. Accordingly, the degree of freedom of the system becomes disadvantageous, and further, the manufacturing cost increases.

[0009] From US 2014 / 0 153 276 A1, a laser optical system for a headlight according to the preamble of claim 1 is known. From JP 2012-038 452 A, another laser optical system for a headlight is known. BRIEF EXPLANATION OF THE INVENTION

[0010] To solve the above-described problems and / or other disadvantages, the present invention provides a laser optical system for a headlight, which is configured such that a laser beam emitted from a laser diode is excited or absorbed by a phosphor and then directly output to an aspherical lens. Accordingly, it can eliminate a light loss area caused by the use of the reflecting body in the related art by not using the reflecting body, thereby minimizing light loss and improving optical efficiency. Specifically, the present invention provides a laser optical system for a headlight that can reduce the size of the optical system, thus achieving weight reduction, saving manufacturing costs, and increasing design freedom.

[0011] Other objects and advantages of the present invention will be understood from the following description and will become apparent with reference to the embodiments of the present invention. Likewise, it will be apparent to those skilled in the art to which the present invention pertains that the objects and advantages of the present invention can be realized by the claimed means and combinations thereof.

[0012] The above-mentioned objects are achieved by a laser optical system for a headlight according to claim 1. Further developments are the subject of the dependent claims.

[0013] According to the present invention, a laser optical system for a headlight comprises a laser diode; a patterned film having a surface on which a microstructure is formed to scatter a laser beam emitted from the laser diode and to specify a width and a height of the beam in accordance with a desired shape; a reflective film having a film opening formed thereon for allowing the laser beam scattered by the patterned film to pass therethrough; a phosphor film formed in a film shape to respond to the laser beam passing through the reflective film to output white light; and an aspherical lens configured to direct the white light passing through the phosphor film toward a front portion, wherein the laser diode and the aspherical lens are arranged in a line.

[0014] The laser optical system further comprises a rear holder in which the pattern film and the reflective film are coupled to and face each other; a front holder in which the phosphor film is combined so that the phosphor film is positioned in front of the reflective film; and a plurality of mounts configured to connect the rear holder and the front holder to each other.

[0015] The laser optical system may further comprise a reflection coating combined with a front surface of the reflective film facing the phosphor film to reflect a part of the laser beam, which is unable to be excited or absorbed by the phosphor film but is scattered to a rear region, to a front region, thereby improving optical efficiency.

[0016] The microstructure may be formed as an elliptical projection to achieve a low beam. The microstructure may be formed as a circular projection to achieve a high beam. The film aperture may be formed with a shape substantially the same as the shape of the microstructure.

[0017] The laser optical system may further include a shield coupled to the front holder to face the phosphor film when a low beam is realized and may have a boundary line formed thereon.

[0018] The reflective coating may comprise a silver-colored reflective silver coating to realize a hidden effect by deposition when the laser diode is turned off.

[0019] According to the present invention, the laser optical system is designed such that the laser beam emitted from the laser diode is excited or absorbed by the phosphor film, and then the white light is directly emitted to the front area through the aspherical lens. Accordingly, the light loss of the optical system can be minimized, and thus the optical efficiency can be increased. Furthermore, by reducing the size of the optical system, weight reduction and saving in manufacturing costs can be achieved, and the degree of design freedom can be increased.

[0020] The devices of the present invention have other features and advantages which will be apparent or explained in more detail from the accompanying drawings incorporated herein and the following detailed description, which together serve to explain certain principles of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS Fig. 1 is a view explaining a laser optical system for a headlight in the related art. Fig. 2 and Fig. 3 are perspective views illustrating an assembled state and an exploded state of an exemplary laser optical system for a headlamp according to the present invention. Fig. 4, Fig. 5 and Fig. 6 are views explaining a microstructure according to the present invention. Fig. 7 is a view explaining a reflective film and a reflective coating according to the present invention. DESCRIPTION OF CERTAIN EMBODIMENTS

[0021] Reference will now be made in detail to various embodiments of the present invention(s), examples of which are illustrated in the accompanying drawings and explained below. While the invention(s) will be explained in connection with exemplary embodiments, it is to be understood that the present description is not intended to limit the invention(s) to these embodiments. On the contrary, the invention(s) are intended to cover not only the exemplary embodiments, but also various alternatives, modifications, equivalents, and other embodiments which may be within the scope of the invention as defined by the appended claims.

[0022] Hereinafter, a laser optical system for a headlight according to various embodiments of the present invention will be described with reference to the accompanying drawings.

[0023] As in Fig. 2 to 7, a laser optical system for a headlight according to the present invention comprises a laser diode 10 which emits a laser beam L1 of a blue wavelength band (e.g.(normally a short wavelength band of about 450 nm); a patterned film 20 having a surface on which a microstructure 21 is formed to scatter the laser beam L1 emitted from the laser diode 10 and to specify or define the height of the beam into a desired shape; a reflective film 30 having a film opening 31 formed thereon to pass the laser beam L2 scattered by the patterned film 20; a phosphor film 40 formed in a film shape to react with the laser beam passing through the reflective film 30 to emit white light L3; and an aspherical lens 50 which directs, condenses, and / or guides the white light passing through the phosphor film 40 to a front region, wherein the laser diode 10 and the aspherical lens 50, and / or other components therebetween, are arranged in line.

[0024] Here, the patterned film 20, the reflective film 30, and the phosphor film 40 are fixedly mounted by means of a holder, and the holder is fixedly mounted in a housing constituting the optical system. The holder includes a rear holder 60 in which the patterned film 20 and the reflective film 30 are combined or coupled to face each other; a front holder 70 in which the phosphor film 40 is combined so that the phosphor film is positioned in front of the reflective film 30; and a plurality of brackets 80 that connect the rear holder 60 and the front holder 70.

[0025] Furthermore, the laser optical system further comprises a reflection coating 90 combined with a front surface of the reflective film 30 facing the phosphor film 40 to reflect the laser beam, which is unable to be excited or absorbed by the phosphor film 40 when the laser diode 10 is turned on but is scattered to a rear portion, back to the front portion to improve optical efficiency (L4 in Fig. 7).

[0026] That is, the beam L1 emitted from the laser diode 10 becomes a beam L2 scattered into a certain shape while passing through the pattern film 20, and the scattered beam L2 is predominantly excited by the phosphor film 40 or absorbed after passing through a film aperture 31 of the reflecting film 30 to emit white light L3.

[0027] However, a portion of the scattered beam L2 cannot be excited or absorbed by the phosphor film 40, but is scattered toward the rear area where the reflective film 30 is present. The reflective coating 90 according to the present invention serves to reflect the laser beam scattered toward the rear area back to the phosphor film 40, thereby greatly reducing the light loss due to the beam scattered toward the rear area. In addition, the overall optical efficiency of the headlight can be greatly improved because the amount of light can be ensured.

[0028] On the other hand, in some embodiments, it is preferred that the reflective coating 90 according to the present invention greatly assists in achieving high lamp quality by realizing a hidden effect by means of deposition when the laser diode 10 is turned off. For this purpose, it is preferred that the reflective coating 90 be a silver-colored reflective silver coating.

[0029] The microstructure 21 according to the present invention may be formed as an elliptical projection 21a which is long in a left and right direction, as shown in Fig. 5 when a low beam is realized, or can be formed as a circular projection 21b, as in Fig. 6 when a high beam is realized.

[0030] Further, it is preferable that the film opening 31 formed on the reflective film 30 is formed in the same shape as the structural shape of the microstructure 21, and thereby the beam structure of a specific shape can be formed.

[0031] On the other hand, when it is intended to realize a low beam using the optical system according to the present invention, the optical system further comprises a shield 100 on which a boundary line 101 is formed. The shield 100 is integrally combined with a front surface part of the front holder 70 to face the phosphor film 40.

[0032] In the case of applying the high beam using the optical system according to the present invention, the shield 100 is not applied in principle.

[0033] Furthermore, in some embodiments, the laser optical system for a headlight according to the present invention further includes a PCB (printed circuit board) that controls the power supply to the laser diode 10, and a heat sink that transfers heat generated by the laser diode 10 and the phosphor film 40 to an outside to dissipate the heat.

[0034] As described above, according to the laser optical system for a headlight according to the present invention, the laser beam emitted from the laser diode 10 is excited or absorbed by the phosphor film 40, and then the white light is directly emitted to the front area through the aspherical lens 50. Accordingly, the light loss area caused by the use of the reflecting body in the related art can be eliminated by not using the reflecting body, and thereby it becomes possible to achieve minimization of light loss and improvement of optical efficiency.

[0035] Furthermore, according to the present invention, all components are arranged in a line without using the reflecting body as in the related art. Accordingly, it becomes possible to reduce the size of the optical system, and consequently, weight reduction, saving in manufacturing costs, and increasing the degree of design freedom can be achieved.

[0036] Furthermore, according to the present invention, the reflective coating 90 reflects a portion of the laser beam that is unable to be excited or absorbed by the phosphor film 40 but is scattered toward the rear, back to the phosphor film 40. Thus, the laser beam is excited or absorbed by the phosphor film 40 to cause white light to be emitted. This can greatly reduce the light loss due to the beam scattered toward the rear. Furthermore, since the amount of light can be ensured, the overall efficiency of the headlight can be greatly improved.

[0037] Furthermore, the reflective coating 90 according to the present invention is of great help in realizing the high quality of the headlight by applying the hidden effect by deposition when the laser diode 10 is turned off.

[0038] For ease of explanation and for accurate definition in the appended claims, the terms "front" or "rear", "left" or "right", etc., are used to refer to features of the exemplary embodiments with reference to the positioning of these features as illustrated in the figures.

[0039] The foregoing descriptions of certain exemplary embodiments of the present invention have been presented for purposes of illustration and description. They are not intended to be exhaustive or to limit the invention to the precise forms disclosed, and obviously many changes and variations are possible in light of the above teachings. The exemplary embodiments were chosen and described in order to explain certain principles of the invention and their practical application so that those skilled in the art will be able to make and use various exemplary embodiments of the present invention, as well as various alternatives and modifications thereof. It is intended that the scope of the invention be defined by the appended claims.

Claims

[1] A laser optical system for a headlight, comprising: a laser diode (10); a structure film (20) having a surface on which a microstructure (21) is formed to scatter a laser beam (L1) emitted from the laser diode (10) and to determine a width and a height of the beam (L1) in accordance with a desired shape; a reflective film (30) having a film opening (31) formed thereon for transmitting the laser beam (L2) which is scattered through the structural film (20); a phosphor film (40) formed in a film shape to respond to the laser beam (L2) passing through the reflective film (30) to emit white light (L3); and an aspherical lens (50) configured to direct the white light (L3) passing through the phosphor film (40) to a front region, wherein the laser diode (10) and the aspherical lens (50) are arranged in a line, characterized by , that the laser optical system further comprises: a rear holder (60) in which the structural film (20) and the reflective film (30) are coupled to each other and face each other; a front holder (70) in which the phosphor film (40) is combined so that the phosphor film (40) is arranged in front of the reflective film (30); and a plurality of brackets (80) configured to interconnect the rear holder (60) and the front holder (70). [2] The laser optical system according to claim 1, further comprising: a reflection coating (90) combined with a front surface of the reflective film (30) facing the phosphor film (40) to reflect a part of the laser beam (L4) that is unable to be excited or absorbed by the phosphor film (40) but is scattered to a rear region to a front region, thereby improving optical efficiency. [3] The laser optical system according to claim 1 or 2, wherein the microstructure (21) is formed as an elliptical projection (21a) to realize a low beam. [4] The laser optical system according to claim 1 or 2, wherein the microstructure (21) is formed as a circular projection (21b) to realize a high beam. [5] The laser optical system according to any one of claims 1-4, wherein the film opening (31) is formed in a shape substantially the same as a shape of the microstructure (21). [6] The laser optical system according to any one of claims 1-5, further comprising: a shield (100) coupled to the front holder (70) to face the phosphor film (40) when a low beam is realized and having a boundary line (101) formed thereon. [7] The laser optical system according to claim 2 or any of claims 3-6 as dependent on claim 2, wherein the reflective coating (90) is a silver-colored reflective silver coating to realize a hidden effect by deposition when the laser diode (10) is turned off.

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