JP6861521B2 - Manufacturing method of light source device, vehicle headlight and light source device - Google Patents

Description

The present invention relates to a light source device, a vehicle headlight, and a method for manufacturing the light source device.

Conventional Technology For example, in the automobile industry, there is a demand for an efficient light source. A known method of generating a strong output optical signal is to use a laser beam to excite and illuminate a fluorescent screen. This fluorescent screen emits a beam, generally isotropically, in all spatial directions. From International Publication No. 2010/084451 (WO2010 / 084451 A1), for example, a light source as described above is known, in which wire lattice polarizers are arranged on both sides of a fluorescent screen. This wire lattice polarizer is used here to reduce the temperature where the laser beam enters the fluorescent screen and excites the fluorescent screen for light emission.

International Publication No. 2010/084451

However, typically only the beam emitted in the forward direction, i.e., in the direction away from the laser, is actually relevant. That is, on average, half of the generated light beam is lost. This is because half of the light beam is emitted in the backward direction, that is, in the direction of the laser.

Disclosure of the Present Invention In the first aspect, the present invention realizes a light source device having the configuration described in the feature portion of claim 1.

Therefore, the present invention realizes a light source device including a laser that emits a light beam and a fluorescent screen in the beam path of the laser. A screen is arranged between the laser and the fluorescent screen, where the screen has at least one opening in the laser beam path through which the light beam emitted by the laser passes. As a result, the light beam emitted by the laser is configured to excite the fluorescent screen to emit light. The screen has a retroreflective layer, which is formed to reflect the light emitted by the fluorescent screen.

In another aspect, the present invention realizes a vehicle headlight having the configuration described in the feature portion of claim 7. Therefore, the present invention includes vehicle headlights having at least one light source device.

In another aspect, the present invention realizes a method of manufacturing a light source device having the configuration described in the feature portion of claim 8.

Therefore, the present invention realizes a method of manufacturing a light source device, which method comprises a first step of arranging a fluorescent screen in the beam path of the laser. In addition, a screen is placed between the laser and the fluorescent screen. At least one opening is formed in the screen to allow the light beam emitted by the laser to pass through. As a result, the light beam transmitted by the laser is incident on the fluorescent screen, and the fluorescent screen can be excited so as to emit light. In addition, a retroreflective layer that reflects the light emitted by the fluorescent screen is formed on the screen.

A favorable form of development is the constituents of each dependent claim.

Advantages of the Invention The retroreflective layer advantageously reflects the light emitted by the fluorescent screen back to the source, the excitation point of the fluorescent screen. The beam is now either transmitted through the fluorescent screen or absorbed by the fluorescent screen, which excites the fluorescent screen to emit light again. Therefore, the available beam output of this light source device, i.e., the overall proportion of the beam finally delivered in the forward direction, is high. The beam emitted backwards of the fluorescent screen is advantageously reflected by the retroreflective layer as completely as possible. Therefore, the beam loss due to the light transmitted backward and not reflected is minimized.

By increasing the available beam output, for example, the number of lasers required for vehicle headlights can be reduced. This not only reduces current consumption, but at the same time reduces the complexity and cost of vehicle headlights.

In an advantageous evolution of the light source device, the screens are spaced apart from the fluorescent screen.

In an advantageous evolution of the light source device, the retroreflective layer comprises a triple mirror reflector, which effectively returns the reflected light back to the point of origin of the light on the fluorescent screen. Is done.

In a favorable development, the light source device comprises a substrate made of glass in particular. Here, the screen and the fluorescent screen are arranged on opposite surfaces of the substrate. This substrate ensures a higher stability of the light source device.

In an advantageous evolution of the light source device, the substrate contains a wire lattice polarizer. The wire grid polarizer also reflects a portion of the incident beam, which can further enhance the effectiveness of the light source device.

In an advantageous evolution of the light source device, the laser is configured as a laser scanner designed to deliver a light beam over an angular range. Here, the diameter of at least one opening of the screen is selected as follows. That is, this diameter is chosen to substantially correspond to the width of this angular range on the screen. In particular, this makes at least one opening of the screen as small as possible, thus minimizing the proportion of the beam emitted by the fluorescent screen that passes through this at least one opening in the direction of the laser and is not reflected. Will be done. This further reduces the unusable beam.

FIG. 6 is a schematic cross-sectional view of the light source device according to the first embodiment of the present invention. The schematic cross-sectional view of the light source apparatus of the 2nd Embodiment of this invention. Schematic cross-sectional view of the light source device. FIG. 6 is a schematic cross-sectional view of the light source device according to the third embodiment of the present invention. FIG. 6 is a schematic cross-sectional view of the light source device according to the fourth embodiment of the present invention. Schematic cross-sectional view of the vehicle headlight of the present invention. The flowchart explaining the manufacturing method of the light source apparatus of this invention.

In all drawings, elements and devices of equivalent or similar function are labeled with the same reference numerals unless otherwise stated. The numbering of steps is for clarity and should not include the meaning of a particular temporal order unless otherwise stated. In particular, it is possible to perform multiple steps at the same time.

Explanation of Examples FIG. 1 shows a schematic cross-sectional view of the light source device 10 according to the first embodiment of the present invention. The light source device 10 here includes a laser 1 that emits a light beam 4. The laser 1 may be configured here, in particular, to emit blue or ultraviolet light.

Laser 1 is advantageously a laser scanner designed to scan over a range of spatial angles. The laser 1 is oriented so as to emit a light beam 4 in an angular range α in the vertical direction. This is done in particular by the swirling of the laser micromirror. In addition to this, the laser 1 can be advantageously oriented to emit the light beam 4 in a certain angular range in the horizontal direction perpendicular to the plane of view.

A fluorescent screen 2, that is, a screen having at least one fluorescent layer is arranged in the beam path of the laser 1. This fluorescent layer is excited by the light beam 4 transmitted by the laser 1 to emit light.

Spaced apart from the phosphor screen by a distance d _3, in the beam path of the laser 1, between the laser 1 and the fluorescent screen 2, the screen 3 is disposed. _{The distance d 3} between the fluorescent screen 2 and the screen 3 may be, for example, 5 mm to 40 mm, preferably 20 mm. The screen 3 has at least one opening 9 through which the light beam 4 delivered by the laser passes. The geometry of the opening 9 is arbitrary here. However, advantageously, the opening 9 is formed in a circular shape. _{The diameter d 1} of the opening 9 of the screen 3 is advantageously selected as follows. That is, the light beam 4 in the entire angle range α is selected so as to be able to pass through the opening 9 of the screen 3. Here, the diameter d ₁ is advantageously selected as small as possible, and the diameter d ₁ advantageously corresponds to the width of the angle range α on the screen 3. Advantageously, the beam waist d ₂ of the light beam 4 is also considered here.

Advantageously, the laser 1 is located in the center, in front of the center point of the opening 9. However, the lasers 1 may be staggered.

The laser beam 4 transmitted by the laser 1 passes through the opening 9 of the screen 3 and is incident on the incident point 6 of the fluorescent screen 2. The fluorescent screen 2 is excited to emit light at the incident point 6. By swirling the laser beam 4 delivered by the laser 1 in the angular range α, the surface having the diameter D on the fluorescence screen 2 is scanned or illuminated by the laser 1. Here, this diameter D is advantageously between 1 cm and 20 cm. However, the present invention is not limited to this. Therefore, the laser 1 can scan and even illuminate a surface of any shape on the fluorescent screen 2.

Hereinafter, the transmission of light in the "rear direction" and the transmission of light in the "forward direction" are distinguished. The space is divided into two half-spaces by the surface on which the fluorescent screen 2 is located. The transmission of the light beam in the "backward direction" means that the light beam spreads here in the half-space in which the laser 1 is present. When the light beam is delivered in the "forward direction", the light beam spreads in the other half-space where the laser 1 is absent.

At least one retroreflective layer 3a is formed on the screen 3. The retroreflective layer 3a may particularly include a triple mirror reflector. However, this retroreflective layer 3a may also include a Renebrug lens. The retroreflective layer 3a may specifically include a spherical element with a metallized back surface.

The size of the openings of the individual reflector elements of the triple mirror reflector can be, for example, about 100 μm. _{When the distance d 3} between the fluorescent screen 2 and the screen 3 is, for example, 20 mm, the diameter of the airy disk on the fluorescent screen 2 is about 280 μm. Here, the airy disk advantageously corresponds approximately to _{the beam waist d 2 of the transmitted laser beam 4.} However, all these numbers are just an example.

The light beam 5a transmitted in the rearward direction is incident on the retroreflective layer of the screen 3. The retroreflective layer is configured to substantially reflect the light beam 5a along a direction opposite to the incident direction of the light beam 5a of the retroreflective layer 3a. That is, the light beam 5b reflected in this way propagates in the direction of the incident point 6 of the fluorescent screen 2. The reflected light beam 5b can pass through the fluorescent screen 2 and then diffuse forward. However, the reflected light beam 5b can also excite the fluorescent screen 2 for the re-delivery of light, which can increase the luminous efficiency of the light.

Finally, the overall ratio of the light beam emitted in the forward direction, i.e., the sum of the beam originally emitted in the forward direction and the reflected beam, is at least 85 of the total light beam emitted by the fluorescent screen. Estimated as%. However, it should be understood that this number is just an example.

The present invention is not limited to the embodiments described above. In particular, the screen 3 can have a large number of openings.

In addition, a number of additional optical elements, in particular the lens, may be attached to the front and / or rear of the fluorescence screen 2.

FIG. 2 shows a second embodiment of the light source device 20 of the present invention. In the first embodiment, the screen 3 was spaced apart from the fluorescent screen 2, that is, separated by air, but in the second embodiment, the screen 3 and the fluorescent screen 2 are a substrate. It is arranged on the opposite surfaces of 7. The substrate 7 may consist of, in particular, glass or another light-transmitting, i.e. transparent or translucent material. The fluorescent screen 2 and the screen 3 are here advantageously fixed to the substrate 7 in a fixed manner, particularly by adhesion or precipitation.

FIG. 3 shows a cross-sectional view of the light source device 30. The light source device 30 includes a laser 1 that emits a light beam 4. The laser 1 is advantageously a laser scanner designed to emit the light beam 4 in the vertical direction in the angular range α. This is done in particular by the swirling of the laser micromirror. A fluorescent screen 2 is formed in the beam path of the laser 1. The fluorescent screen 2 is arranged on the surface of the substrate 7 opposite to the laser. The substrate 7 here includes a wire lattice polarizer 8, an array of parallel metal wires with good conductivity. The light beam 4 transmitted by the laser 1 is configured to excite the fluorescence screen 2 so as to emit light. The light beam 5c delivered in the rearward direction can be reflected here, at least in part, by the wire lattice polarizer 8. The light beam 5d thus reflected here again enters the fluorescent screen 2 and excites the fluorescent screen 2 so as to repeatedly transmit light, or passes through the fluorescent screen 2 and moves forward. Propagate.

The light emitted by the fluorescent screen 2 is here generally polarized randomly. That is, it does not have a special polarization direction. The light beam 5c is transmitted or reflected based on the polarization of the wire lattice polarizer. For example, at an incident angle of 45 °, the transmittance of the p-polarized component with respect to the wire lattice polarizer is about 85%. The proportion of reflected, s-polarized components can be estimated as about 85%. Based on this, it is expected that at least 60% of the light will eventually be emitted forward. However, it should be understood that this number is just an example.

FIG. 4 shows a cross-sectional view of the light source device 40 according to the third embodiment of the present invention. This third embodiment differs from the second embodiment shown in FIG. 2 in the following points. That is, the difference is that the wire lattice polarizer 8 is formed between the fluorescent screen 2 and the screen 3 in the substrate 7 as in the light source device 30 shown in FIG. The wire lattice polarizer 8 can now reflect the light beam 5c transmitted in the rearward direction. The light beam 5d reflected in this way passes through the fluorescent screen 2 or excites the fluorescent screen so as to emit light again.

FIG. 5 shows a cross-sectional view of the light source device 50 according to the fourth embodiment of the present invention. This fourth embodiment differs from the third embodiment shown in FIG. 4 in the following points. That is, they differ in that _{the distance d 3} between the fluorescent screen 2 and the screen 3 _{is larger than the thickness d 4 of the} substrate 7 having the wire lattice polarizer 8. Therefore, the screen 3 is arranged at a distance from the substrate 7.

FIG. 6 shows a cross-sectional view of a vehicle headlight 60 having the light source device 10 of the first embodiment. The vehicle headlight 60 has a housing 51 here. Here, the fluorescent screen 2 is arranged in the opening of the housing 51. The fluorescent screen 2 is protected by the shielding portion 52 from the influence of the surroundings. The shield 52 further includes a lens system. This lens system is oriented so as to transmit the light transmitted by the fluorescent screen 2 to the outside at a predetermined angle. The laser 1 is arranged here as follows. That is, the transmitted light beam 4 enters the fluorescent screen 2 through the opening 9 of the screen 3, and the light propagated forward by the fluorescent screen 2 passes through the shielding portion 10 and is a headlight for a vehicle. It is arranged so that it radiates from 60 to the outside.

The present invention is not limited to this, and other embodiments of the light source device for the vehicle headlight 60 can also be used.

FIG. 7 shows a flowchart illustrating a method for manufacturing the light source device of the present invention.

In the first step S1, the fluorescence screen 2 is arranged in the beam path of the laser 1, especially the laser scanner. The laser 1 is advantageously configured to emit the light beam 4 in the angular range α. In the second step S2, the screen 3 is arranged between the laser 1 and the fluorescent screen 2. In the screen 3, at least one opening 9 through which the light beam 4 transmitted by the laser 1 is passed is formed in the third step S3. Advantageously, a large number of openings are formed here in the screen 3. _{The diameter d 1} of the opening 9 of the screen 3 here, advantageously, substantially corresponds to _{the beam waist d 2} of the light beam 4 delivered by the laser 1. The light beam 4 transmitted by the laser 1 passes through at least one opening and is incident on the fluorescence screen 2 at the incident point 6. As a result, the fluorescent screen 2 is excited to emit light.

In the fourth step S4, the retroreflective layer 3a is formed on the screen 3. Here, the retroreflective layer 3a is configured such that the light transmitted backward by the fluorescent screen 2 is incident on the retroreflective layer 3a and reflected there.

Claims (8)

A laser (1) for transmitting an optical beam (4) and
The fluorescent screen (2) in the beam path of the laser (1) and
A screen (3) which is disposed between said phosphor screen and laser (1) (2),
A substrate (7) arranged between the screen (3) and the fluorescent screen (2),
Light source device (10, 20, 40, 50) equipped with
The screen (3) in the beam path of the laser (1) has at least one opening through which the light beam (4) delivered by the laser (1) passes. The light beam (4) transmitted by the laser (1) is configured to excite the fluorescent screen (2) so as to emit light (5a, 5c).
The screen (3) has a retroreflective layer (3a) formed to reflect the light (5a) transmitted by the fluorescent screen (2) .
The substrate (7) contains a wire lattice polarizer (8) .
A light source device (10, 20, 40, 50). The light source device (10, 20, 40, 50) according to claim 1, wherein the screen (3) is _{arranged at a distance (d 3) from the fluorescent screen (2).} The light source device (10, 20, 40, 50) according to claim 1 or 2, wherein the retroreflective layer (3a) includes a triple mirror reflector. The pre-Symbol screen (3) and said phosphor screen (2), wherein are arranged on opposite surfaces of the substrate (7), the light source apparatus according to any one of claims 1 to 3 (20, 40 , 50). The light source device (40, 50) according to any one of claims 1 to 4, wherein the substrate (7) is made of glass. The laser (1) is configured as a laser scanner.
The laser scanner is designed to emit the light beam (4) in the angle range α.
Any of claims 1 to 5 _{, wherein the diameter (d 1} ) of the at least one opening of the screen (3) is selected to correspond to the width of the angle range α on the screen (3). The light source device (10, 20, 40, 50) according to item 1. It has at least one light source device (10, 20, 40, 50) according to any one of claims 1 to 6.
Vehicle headlights (60). It is a manufacturing method of a light source device (10, 20, 40, 50).
In the step (S1) of arranging the fluorescent screen (2) in the beam path of the laser (1),
A step (S2) of placing a screen (3) between said laser (1) wherein a phosphor screen (2),
A step of arranging a substrate (7) containing a wire lattice polarizer (8) between the screen (3) and the fluorescent screen (2), and a step of arranging the substrate (7).
The light beam (4) transmitted by the laser (1) can enter the fluorescent screen (2) and excite the fluorescent screen (2) so as to emit light (5a, 5c). In addition, a step (S3) of forming at least one opening in the screen (3) through which the light beam (4) transmitted by the laser (1) passes.
A step (S4) of forming a retroreflective layer (3a) on the screen (3) in order to reflect the light (5a) transmitted by the fluorescent screen (2).
A method for manufacturing a light source device (10, 20, 40, 50).

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