WO2024131722A1 - An optical device for modifying light distribution - Google Patents

An optical device for modifying light distribution Download PDF

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Publication number
WO2024131722A1
WO2024131722A1 PCT/CN2023/139491 CN2023139491W WO2024131722A1 WO 2024131722 A1 WO2024131722 A1 WO 2024131722A1 CN 2023139491 W CN2023139491 W CN 2023139491W WO 2024131722 A1 WO2024131722 A1 WO 2024131722A1
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WO
WIPO (PCT)
Prior art keywords
light
optical device
egress surface
geometric plane
light egress
Prior art date
Application number
PCT/CN2023/139491
Other languages
French (fr)
Inventor
Kimmo Harjunpaa
Original Assignee
Ledil Optics Technology (Shenzhen) Ltd.
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Ledil Optics Technology (Shenzhen) Ltd. filed Critical Ledil Optics Technology (Shenzhen) Ltd.
Publication of WO2024131722A1 publication Critical patent/WO2024131722A1/en

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Classifications

    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F21—LIGHTING
    • F21S—NON-PORTABLE LIGHTING DEVICES; SYSTEMS THEREOF; VEHICLE LIGHTING DEVICES SPECIALLY ADAPTED FOR VEHICLE EXTERIORS
    • F21S41/00—Illuminating devices specially adapted for vehicle exteriors, e.g. headlamps
    • F21S41/20—Illuminating devices specially adapted for vehicle exteriors, e.g. headlamps characterised by refractors, transparent cover plates, light guides or filters
    • F21S41/25—Projection lenses
    • F21S41/275—Lens surfaces, e.g. coatings or surface structures
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F21—LIGHTING
    • F21S—NON-PORTABLE LIGHTING DEVICES; SYSTEMS THEREOF; VEHICLE LIGHTING DEVICES SPECIALLY ADAPTED FOR VEHICLE EXTERIORS
    • F21S41/00—Illuminating devices specially adapted for vehicle exteriors, e.g. headlamps
    • F21S41/10—Illuminating devices specially adapted for vehicle exteriors, e.g. headlamps characterised by the light source
    • F21S41/14—Illuminating devices specially adapted for vehicle exteriors, e.g. headlamps characterised by the light source characterised by the type of light source
    • F21S41/141—Light emitting diodes [LED]
    • F21S41/143—Light emitting diodes [LED] the main emission direction of the LED being parallel to the optical axis of the illuminating device
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F21—LIGHTING
    • F21S—NON-PORTABLE LIGHTING DEVICES; SYSTEMS THEREOF; VEHICLE LIGHTING DEVICES SPECIALLY ADAPTED FOR VEHICLE EXTERIORS
    • F21S41/00—Illuminating devices specially adapted for vehicle exteriors, e.g. headlamps
    • F21S41/20—Illuminating devices specially adapted for vehicle exteriors, e.g. headlamps characterised by refractors, transparent cover plates, light guides or filters
    • F21S41/25—Projection lenses
    • F21S41/255—Lenses with a front view of circular or truncated circular outline
    • G—PHYSICS
    • G02—OPTICS
    • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
    • G02B19/00—Condensers, e.g. light collectors or similar non-imaging optics
    • G02B19/0004—Condensers, e.g. light collectors or similar non-imaging optics characterised by the optical means employed
    • G02B19/0028—Condensers, e.g. light collectors or similar non-imaging optics characterised by the optical means employed refractive and reflective surfaces, e.g. non-imaging catadioptric systems
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F21—LIGHTING
    • F21W—INDEXING SCHEME ASSOCIATED WITH SUBCLASSES F21K, F21L, F21S and F21V, RELATING TO USES OR APPLICATIONS OF LIGHTING DEVICES OR SYSTEMS
    • F21W2102/00—Exterior vehicle lighting devices for illuminating purposes
    • F21W2102/10—Arrangement or contour of the emitted light
    • F21W2102/13—Arrangement or contour of the emitted light for high-beam region or low-beam region
    • F21W2102/135—Arrangement or contour of the emitted light for high-beam region or low-beam region the light having cut-off lines, i.e. clear borderlines between emitted regions and dark regions
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F21—LIGHTING
    • F21Y—INDEXING SCHEME ASSOCIATED WITH SUBCLASSES F21K, F21L, F21S and F21V, RELATING TO THE FORM OR THE KIND OF THE LIGHT SOURCES OR OF THE COLOUR OF THE LIGHT EMITTED
    • F21Y2115/00—Light-generating elements of semiconductor light sources
    • F21Y2115/10—Light-emitting diodes [LED]
    • G—PHYSICS
    • G02—OPTICS
    • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
    • G02B19/00—Condensers, e.g. light collectors or similar non-imaging optics
    • G02B19/0033—Condensers, e.g. light collectors or similar non-imaging optics characterised by the use
    • G02B19/0047—Condensers, e.g. light collectors or similar non-imaging optics characterised by the use for use with a light source
    • G02B19/0061—Condensers, e.g. light collectors or similar non-imaging optics characterised by the use for use with a light source the light source comprising a LED

Definitions

  • the disclosure relates generally to illumination engineering. More particularly, the disclosure relates to an optical device for modifying a distribution of light produced by a light source that can be, for example but not necessarily, a light emitting diode “LED” . Furthermore, the disclosure relates to a low-beam headlight element for a vehicle and to a vehicle.
  • FIG. 1a shows a side view of a low-beam headlight element 112
  • figure 1b shows a top view of the low-beam headlight element
  • figure 1c shows a schematic illustration of a light distribution pattern which is formed on a virtual screen 115 provided in a forward position from the low-beam headlight element.
  • the virtual screen 115 is parallel with the xy-plane of a coordinate system 199, and the light distribution pattern is schematically presented as a cross-hatched area in figure 1c.
  • the light distribution pattern is required to have a cutoff line 116 above which the intensity of the light should be sufficiently low to avoid glaring drivers of oncoming vehicles.
  • Concerning the cutoff line 116 there can be for example rules which define an allowed range for angle ⁇ illustrated in figures 1a and 1c. For example, the angle ⁇ can be required to be on the range from–0.5 degrees to+0.5 degrees.
  • a typical arrangement for producing the cutoff line 116 in the light distribution pattern is to provide the low-beam headlight element 112 with a screen element which cuts out a portion of the light that would otherwise fall on the region above the cutoff line 116.
  • An inherent inconvenience related to this approach is that the screen element reduces the amount of light radiated by the low-beam headlight element. Furthermore, the screen element converts at least part of the screened light into heat and thus warms up the low-beam headlight element.
  • geometric when used as a prefix means a geometric concept that is not necessarily a part of any physical object.
  • the geometric concept can be for example a geometric point, a straight or curved geometric line, a geometric plane, a non-planar geometric surface, a geometric space, or any other geometric entity that is zero, one, two, or three dimensional.
  • a new optical device for modifying a distribution of light produced by a light source.
  • the optical device can be used, for example, as a part of a low-beam headlight element.
  • An optical device comprises:
  • a center section constituting a lens portion configured to modify a distribution of a first part of light emitted by a light source
  • peripheral section surrounding and connected to the center section and comprising a reflective surface configured to modify a distribution of a second part of the light emitted by the light source.
  • the lens portion has a first light egress surface configured to refract the first part of the light
  • the peripheral section has a second light egress surface shaped to have grooves parallel to each other and configured to spread the second part of the light in a direction perpendicular to the grooves.
  • the first light egress surface of the lens portion is asymmetric with respect to a geometric plane intersecting a top of the first light egress surface and perpendicular to the grooves so that:
  • a second part of the first light egress surface on a second side of the first geometric plane is convex
  • the first part of the first light egress surface is more convex than the second part of the first light egress surface to configure the first part of the first light egress surface to refract a part of the light penetrating the first part of the first light egress surface more towards the first geometric plane than a part of the light penetrating the second part of the first light egress surface.
  • the more convex first part of the first light egress surface refracts light penetrating the first part of the first light egress surface so that a desired cutoff line is produced in the distribution pattern of the light. Therefore, for achieving the cutoff line, there is no need for screening the light emitted by a light source and thus the amount of light coming out from the optical device can be greater than in a corresponding case in which a part of light is screened by a screen element.
  • a new low-beam headlight element that comprises:
  • an optical device for modifying a distribution of light emitted by the light source.
  • a new vehicle that comprises at least one low-beam headlight element according to the invention.
  • the low-beam headlight element is positioned in the vehicle so that the grooves of the second light egress surface of the optical device are vertical and the first part of the first light egress surface is above the second part of the first light egress surface when the vehicle is on a horizontal surface in the normal operating position of the vehicle.
  • vehicle can apply to any transportation mode such as, for example, an automobile, a motorcycle, a mobile working machine, a railcar, etc.
  • a new mold having a form suitable for manufacturing, by mold casting, a transparent piece constituting an optical device according to the invention.
  • FIG. 1a, 1b, and 1c illustrate the operation of a low-beam headlight element according to the prior art
  • FIGS. 2a, 2b, and 2c illustrate an optical device according to an exemplifying and non-limiting embodiment
  • FIG. 3a, 3b, 3c, 3d, 3e, and 3f illustrate functionality of a light source and an optical device according to an exemplifying and non-limiting embodiment
  • FIGS. 4a and 4b illustrate an optical device according to an exemplifying and non-limiting embodiment and figure 4c shows a light distribution pattern obtained with the optical device illustrated in figures 4a and 4b, and
  • figure 5 shows a schematic illustration of a vehicle according to an exemplifying embodiment.
  • Figure 2a shows an isometric view of an optical device 201 according to an exemplifying and non-limiting embodiment.
  • Figure 2b shows a front view of the optical device 201
  • figure 2c shows a section view of the optical device 201.
  • the geometric section plane related to figure 2c is parallel with the yz-plane of a coordinate system 299.
  • the optical device 201 comprises a center section 202 that constitutes a lens portion configured to modify a distribution of a first part of light emitted by a light source 211.
  • the lens portion has a first light egress surface 205 configured to refract the first part of the light.
  • the lens portion has a light ingress surface 210 which can be convex, planar, or concave depending on requirements of the optical device.
  • the light ingress surface 210 of the lens portion is convex.
  • the optical device 201 comprises a peripheral section 203 that surrounds and is connected to the center section 202.
  • the peripheral section 203 comprises a reflective surface 204 configured to modify a distribution of a second part of the light emitted by the light source 211.
  • the peripheral section 203 comprises a second light egress surface 206 shaped to have grooves parallel to each other and configured to spread the second part of the light in a direction perpendicular to the grooves, i.e. in a direction parallel with the x-axis of the coordinate system 299.
  • the first light egress surface 205 of the lens portion is asymmetric with respect to a first geometric plane intersecting the top of the first light egress surface 205 and perpendicular to the grooves of the second light egress surface 206.
  • the first geometric plane is parallel with the xz-plane of the coordinate system 299.
  • the first geometric plane is depicted with a line and denoted with reference 207.
  • the first light egress surface 205 is asymmetric with respect to the first geometric plane 207 so that i) afirst part 208 of the first light egress surface 205 on a first side of the first geometric plane 207 is convex, ii) a second part 209 of the first light egress surface 205 on a second side of the first geometric plane 207 is convex, and iii) the first part 208 of the first light egress surface 205 is more convex than the second part 209 of the first light egress surface 205 to configure the first part 208 of the first light egress surface 205 to refract light penetrating the first part 208 of the first light egress surface 205 more towards the first geometric plane 207 than light penetrating the second part 209 of the first light egress surface 205, as shown in figure 2c.
  • the more convex first part 208 of the first light egress surface 205 refracts light penetrating the first part 208 of the first light egress surface 205 so that a desired cutoff line is produced in the distribution pattern of the light coming out from the optical device 201. Therefore, for achieving the cutoff line, there is no need for screening the light emitted by a light source 211 and thus the amount of the light coming out from the optical device 201 can be greater than in a corresponding case in which a part of light is screened by a screen element.
  • the reflective surface 204 is asymmetric with respect to the first geometric plane 207 so that light reflected on the first side of the first geometric plane 207 is reflected more towards the first geometric plane 207 than light reflected on the second side of the first geometric plane 207.
  • the asymmetricity of the reflective surface 204 is expressed by that a profile 220 of the reflective surface 204 is steeper than a profile 221 of the reflective surface 204.
  • the steeper-shaped profile 220 of the reflective surface 204 reflects light so that a desired cutoff line is produced in the distribution pattern of the light.
  • the exemplifying optical device 201 illustrated in figures 2a-2c is a single piece of transparent material that can be for example acrylic plastic, polycarbonate, optical silicone, glass, or some other suitable transparent material.
  • the reflective surface 204 of the peripheral section 203 is a surface of the transparent material for providing total internal reflection “TIR” .
  • an optical device according to an exemplifying and non-limiting embodiment comprises elements connected to each other.
  • the center section 202 and the peripheral section 203 can be manufactured as separate elements which are joined together.
  • the optical device, or its elements, can be manufactured for example with mold casting.
  • the bottoms of the grooves on the second light egress surface 206 have a U-shaped cross-sectional profile and ridges between the grooves have a ⁇ -shaped cross-sectional profile. It is also possible that an optical device according to an exemplifying and non-limiting embodiment has grooves having a different shape, e.g. a V-shaped cross-sectional profile.
  • the light source 211 and the optical device 201 illustrated in figure 2c constitute functional elements of a low-beam headlight element according to an exemplifying and non-limiting embodiment.
  • a frame structure of the low-beam headlight element configured to mechanically support the light source 211 and the optical device 201 is not shown.
  • Figures 3a, 3b, 3c, 3d, 3e, and 3f illustrate functionality of the light source 211 and the optical device 201.
  • Figures 3a and 3b illustrate a light distribution pattern of the above-mentioned first part of the light that has penetrated the center section 202 of the optical device 201.
  • Acurve 317a in figure 3a illustrates the light distribution pattern of the first part of the light on the first geometric plane 207 shown in figure 2c.
  • Acurve 318a in figure 3a illustrates the light distribution pattern of the first part of the light on the second geometric plane that is the geometric section plane of the section view shown in figure 2c.
  • FIG. 3b shows the light distribution pattern of the first part of the light on a virtual screen that is parallel with the xy-plane of the coordinate system 299 shown in figure 2c. As shown in figure 3b, the upper rim of the light distribution pattern is straighter than the lower rim of the light distribution pattern.
  • Figures 3c and 3d illustrate a light distribution pattern of the above-mentioned second part of the light that has penetrated the peripheral section 203 of the optical device 201.
  • Acurve 317b in figure 3c illustrates the light distribution pattern of the second part of the light on the first geometric plane 207 shown in figure 2c.
  • a curve 318b in figure 3c illustrates the light distribution pattern of the second part of the light on the second geometric plane that is the geometric section plane of the section view shown in figure 2c.
  • Figure 3d shows the light distribution pattern of the second part of the light on a virtual screen that is parallel with the xy-plane of the coordinate system 299 shown in figure 2c.
  • Figures 3e and 3f illustrate a superposition of the light distribution patterns illustrated in figures 3a-3d.
  • Acurve 317c in figure 3e illustrates the light distribution pattern of the first and second parts of the light on the first geometric plane 207 shown in figure 2c.
  • Acurve 318c in figure 3e illustrates the light distribution pattern of the first and second parts of the light on the second geometric plane that is the geometric section plane of the section view shown in figure 2c.
  • Figure 3f shows the light distribution pattern of the first and second parts of the light on a virtual screen that is parallel with the xy-plane of the coordinate system 299 shown in figure 2c.
  • Figures 4a and 4b illustrate an optical device 401 according to an exemplifying and non-limiting embodiment.
  • Figure 4c shows a light distribution pattern obtained with a light source and the optical device 401 on a virtual screen that is parallel with the xy-plane of the coordinate system 499 shown in figures 4a and 4b.
  • the light source is not shown in figures 4a and 4b.
  • the optical device 401 comprises a center section 402 that constitutes a lens portion configured to modify a distribution of a first part of light emitted by the light source.
  • the lens portion has a first light egress surface 405 configured to refract the first part of the light.
  • the optical device 401 comprises a peripheral section 403 that surrounds and is connected to the center section 402.
  • the peripheral section 403 comprises a reflective surface configured to modify a distribution of a second part of the light emitted by the light source.
  • the reflective surface is not shown in figures 4a and 4b, but the reflective surface of the optical device 401 can be like the reflective surface of the optical device 201 illustrated in figures 2a-2c.
  • the peripheral section 403 comprises a second light egress surface 406 shaped to have grooves parallel to each other and configured to spread the second part of the light in a direction perpendicular to the grooves, i.e. in a direction parallel with the x-axis of the coordinate system 499.
  • the first light egress surface 405 of the lens portion is asymmetric with respect to a first geometric plane intersecting the top of the first light egress surface 405 and perpendicular to the grooves of the second light egress surface 406.
  • the first geometric plane is parallel with the xz-plane of the coordinate system 499.
  • the first geometric plane is depicted with a line and denoted with reference 407.
  • the first light egress surface 405 comprises a first part 408, a second part 409, and a third part 422.
  • the first part 408 of the first light egress surface 405 is convex and the first part 408 is on a first side of the first geometric plane 407.
  • the second part 209 of the first light egress surface 405 is convex and the second part 409 is on a second side of the first geometric plane 407.
  • the first part 408 is more convex than the second part 409 to configure the first part 408 to refract light penetrating the first part 408 more towards the first geometric plane 407 than light penetrating the second part 409.
  • the third part 422 of the first light egress surface 405 is convex and most of the third part 408 is on the first side of the first geometric plane 407.
  • the first part 408 of the first light egress surface 405 is more convex than the third part 422 to configure the first part 408 to refract the light penetrating the first part 408 more towards the first geometric plane 407 than light penetrating the third part 422 of the first light egress surface 405.
  • the horizontal part of the upper edge of the light distribution pattern shown in figure 4c is caused by light refraction in the first part 408 of the first light egress surface 405 whereas the right ascending part of the upper edge of the light distribution pattern is caused by light refraction in the third part 422 of the first light egress surface 405. Due to the asymmetric light distribution pattern shown in figure 4c, the optical device 401 is suitable for being a part of a low-beam headlight element of an automobile.
  • the first part 408 of the first light egress surface 405 is on a first side of a second geometric plane intersecting the top of the first light egress surface 405 and perpendicular to the first geometric plane 407.
  • the third part 422 of the first light egress surface 405 is on a second side of the second geometric plane.
  • the second geometric plane is parallel with the yz-plane of the coordinate system 499.
  • the second geometric plane is depicted with a line and denoted with reference 423.
  • the first part 408 of the first light egress surface 405 covers from 20%to 30%of the total area of the first light egress surface 405
  • the second part 409 of the first light egress surface 405 covers from 40%to 60%of the total area of the first light egress surface 405
  • the third part 422 of the first light egress surface 405 covers from 20%to 30%of the total area of the first light egress surface 405.
  • FIG. 5 shows a schematic illustration of a vehicle 513 according to an exemplifying embodiment.
  • the vehicle 513 comprises low-beam headlight elements according to an embodiment of the invention.
  • One of the low-beam headlight elements is denoted with a reference 512.
  • the low-beam headlight element comprises a light source 511 and an optical device 501 according to an exemplifying and non-limiting embodiment for modifying a distribution of light emitted by the light source 511.
  • the optical device 501 can be for example like the optical device 201 illustrated in figures 2a-2c or like the optical device 401 illustrated in figures 4a and 4b.
  • Each of the low-beam headlight elements is positioned in the vehicle 513 so that the grooves of the light egress surface of the peripheral section of the optical device 501 are vertical and the first part of the light egress surface of the lens portion of the optical device 501 is above the second part of the light egress surface of the lens portion when the vehicle 513 is on a horizontal surface 514 in a normal operating position of the vehicle.
  • the exemplifying vehicle 513 shown in figure 5 is an automobile, but it is also possible that a vehicle according to an exemplifying embodiment is a motorcycle, amobile working machine, a railcar, or some other kind of vehicle.

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  • Engineering & Computer Science (AREA)
  • Physics & Mathematics (AREA)
  • General Engineering & Computer Science (AREA)
  • Optics & Photonics (AREA)
  • General Physics & Mathematics (AREA)
  • Microelectronics & Electronic Packaging (AREA)
  • Non-Portable Lighting Devices Or Systems Thereof (AREA)

Abstract

An optical device (201) comprises a center section (202) constituting a lens portion for modifying a distribution of a first part of light and a peripheral section (203) surrounding and connected to the center section and comprising a reflective surface (204) for modifying a distribution of a second part of the light. The lens portion has a first light egress surface (205) and the peripheral section has a second light egress surface (206) having grooves for spreading the second part of the light in a direction perpendicular to the grooves. The first light egress surface is asymmetric with respect to a geometric plane (207) intersecting a top of the first light egress surface and perpendicular to the grooves so that a cutoff line is formed in a resulting light distribution pattern.

Description

An optical device for modifying light distribution
Field of the disclosure
The disclosure relates generally to illumination engineering. More particularly, the disclosure relates to an optical device for modifying a distribution of light produced by a light source that can be, for example but not necessarily, a light emitting diode “LED” . Furthermore, the disclosure relates to a low-beam headlight element for a vehicle and to a vehicle.
Background
Operation of a low-beam headlight element of a vehicle is regulated by rules and limitations concerning the light distribution pattern produced by the low-beam headlight element. The operation of a low-beam headlight element is illustrated with the aid of figures 1a, 1b, and 1c, where figure 1a shows a side view of a low-beam headlight element 112, figure 1b shows a top view of the low-beam headlight element, and figure 1c shows a schematic illustration of a light distribution pattern which is formed on a virtual screen 115 provided in a forward position from the low-beam headlight element. The virtual screen 115 is parallel with the xy-plane of a coordinate system 199, and the light distribution pattern is schematically presented as a cross-hatched area in figure 1c. The light distribution pattern is required to have a cutoff line 116 above which the intensity of the light should be sufficiently low to avoid glaring drivers of oncoming vehicles. Concerning the cutoff line 116, there can be for example rules which define an allowed range for angleαillustrated in figures 1a and 1c. For example, the angleαcan be required to be on the range from–0.5 degrees to+0.5 degrees.
A typical arrangement for producing the cutoff line 116 in the light distribution pattern is to provide the low-beam headlight element 112 with a screen element which cuts out a portion of the light that would otherwise fall on the region above the cutoff line 116. An inherent inconvenience related to this approach is that the screen element reduces the amount of light radiated by the low-beam headlight element. Furthermore, the screen element converts at least part of the screened light into heat and thus warms up the low-beam headlight element.
Summary
The following presents a simplified summary to provide a basic understanding of some aspects of various invention embodiments. The summary is not an extensive overview of the invention. It is neither intended to identify key or critical elements of the invention nor to delineate the scope of the invention. The following summary merely presents some concepts of the invention in a simplified form as a prelude to a more detailed description of exemplifying embodiments of the invention.
In this document, the word “geometric” when used as a prefix means a geometric concept that is not necessarily a part of any physical object. The geometric concept can be for example a geometric point, a straight or curved geometric line, a geometric plane, a non-planar geometric surface, a geometric space, or any other geometric entity that is zero, one, two, or three dimensional.
In accordance with the invention, there is provided a new optical device for modifying a distribution of light produced by a light source. The optical device can be used, for example, as a part of a low-beam headlight element.
An optical device according to the invention comprises:
- a center section constituting a lens portion configured to modify a distribution of a first part of light emitted by a light source, and
- a peripheral section surrounding and connected to the center section and comprising a reflective surface configured to modify a distribution of a second part of the light emitted by the light source.
The lens portion has a first light egress surface configured to refract the first part of the light, and the peripheral section has a second light egress surface shaped to have grooves parallel to each other and configured to spread the second part of the light in a direction perpendicular to the grooves.
The first light egress surface of the lens portion is asymmetric with respect to a geometric plane intersecting a top of the first light egress surface and perpendicular to the grooves so that:
- a first part of the first light egress surface on a first side of the first geometric plane is convex,
- a second part of the first light egress surface on a second side of the first geometric plane is convex, and
- the first part of the first light egress surface is more convex than the second part of the first light egress surface to configure the first part of the first light egress surface to refract a part of the light penetrating the first part of the first light egress surface more towards the first geometric plane than a part of the light penetrating the second part of the first light egress surface.
The more convex first part of the first light egress surface refracts light penetrating the first part of the first light egress surface so that a desired cutoff line is produced in the distribution pattern of the light. Therefore, for achieving the cutoff line, there is no need for screening the light emitted by a light source and thus the amount of light coming out from the optical device can be greater than in a corresponding case in which a part of light is screened by a screen element.
In accordance with the invention, there is also provided a new low-beam headlight element that comprises:
- a light source, and
- an optical device according to the invention for modifying a distribution of light emitted by the light source.
In accordance with the invention, there is also provided a new vehicle that comprises at least one low-beam headlight element according to the invention. The low-beam headlight element is positioned in the vehicle so that the grooves of the second light egress surface of the optical device are vertical and the first part of the first light egress surface is above the second part of the first light egress surface when the vehicle is on a horizontal surface in the normal operating position of the vehicle. In this document, the term “vehicle” can apply to any transportation mode such as, for example, an automobile, a motorcycle, a mobile working machine, a railcar, etc.
In accordance with the invention, there is also provided a new mold having a form suitable for manufacturing, by mold casting, a transparent piece constituting an optical device according to the invention.
Exemplifying and non-limiting embodiments are described in accompanied dependent claims.
Various exemplifying and non-limiting embodiments both as to constructions and to methods of operation, together with additional objects and advantages thereof, will be best understood from the following description of specific exemplifying embodiments when read in conjunction with the accompanying drawings.
The verbs “to comprise” and “to include” are used in this document as open limitations that neither exclude nor require the existence of also un-recited features.
The features recited in dependent claims are mutually freely combinable unless otherwise explicitly stated.
Furthermore, it is to be understood that the use of “a” or “an” , i.e. a singular form, throughout this document does not exclude a plurality.
Brief description of figures
Exemplifying and non-limiting embodiments and their advantages are explained in greater detail below with reference to the accompanying drawings, in which:
figures 1a, 1b, and 1c illustrate the operation of a low-beam headlight element according to the prior art,
figures 2a, 2b, and 2c illustrate an optical device according to an exemplifying and non-limiting embodiment,
figures 3a, 3b, 3c, 3d, 3e, and 3f illustrate functionality of a light source and an optical device according to an exemplifying and non-limiting embodiment,
figures 4a and 4b illustrate an optical device according to an exemplifying and non-limiting embodiment and figure 4c shows a light distribution pattern obtained with the optical device illustrated in figures 4a and 4b, and
figure 5 shows a schematic illustration of a vehicle according to an exemplifying embodiment.
Figures 1a, 1b, and 1c have already been explained in the Background-section of this document.
Description of exemplifying and non-limiting embodiments
The specific examples provided in the description given below should not be construed as limiting the scope and/or the applicability of the appended claims. Lists and groups of examples provided in the description given below are not exhaustive unless otherwise explicitly stated.
Figure 2a shows an isometric view of an optical device 201 according to an exemplifying and non-limiting embodiment. Figure 2b shows a front view of the optical device 201, and figure 2c shows a section view of the optical device 201. The geometric section plane related to figure 2c is parallel with the yz-plane of a coordinate system 299. The optical device 201 comprises a center section 202 that constitutes a lens portion configured to modify a distribution of a first part of light emitted by a light source 211. The lens portion has a first light egress surface 205 configured to refract the first part of the light. The lens portion has a light ingress surface 210 which can be convex, planar, or concave depending on requirements of the optical device. In this exemplifying optical device 201, the light ingress surface 210 of the lens portion is convex. The optical device 201 comprises a peripheral section 203 that surrounds and is connected to the center section 202. The peripheral section 203 comprises a reflective surface 204 configured to modify a distribution of a second part of the light emitted by the light source 211. Furthermore, the peripheral section 203 comprises a second light egress surface 206 shaped to have grooves parallel to each other and configured to spread the second part of the light in a direction perpendicular to the grooves, i.e. in a direction parallel with the x-axis of the coordinate system 299. In figure 2c, exemplifying light beams belonging to the above-mentioned first part of the light are depicted with dashed line arrows and exemplifying light beams belonging to the above-mentioned second part of the light are depicted with dash-and-dot line arrows.
The first light egress surface 205 of the lens portion is asymmetric with respect to a first geometric plane intersecting the top of the first light egress surface 205 and perpendicular to the grooves of the second light egress surface 206. In figures 2a-2c, the first geometric plane is parallel with the xz-plane of the coordinate system 299. In figure 2c, the first geometric plane is depicted with a line and denoted with reference 207. The first light egress surface 205 is asymmetric with respect to the first geometric plane 207 so that i) afirst part 208 of the first light egress surface 205 on a first side of the first geometric plane 207 is convex, ii) a second part 209 of the first light egress surface 205 on a second side of the first geometric plane 207 is convex, and iii) the first part 208 of the first light egress surface 205 is more convex than the second part 209 of the first light egress surface 205 to configure the first part 208 of the first light egress surface 205 to refract light penetrating the first part 208 of the first light egress surface 205 more towards the first geometric plane 207 than light penetrating the second part 209 of the first light egress surface 205, as shown in figure 2c.
The more convex first part 208 of the first light egress surface 205 refracts light penetrating the first part 208 of the first light egress surface 205 so that a desired cutoff line is produced in the distribution pattern of the light coming out from the optical device 201. Therefore, for achieving the cutoff line, there is no need for screening the light emitted by a light source 211 and thus the amount of the light coming out from the optical device 201 can be greater than in a corresponding case in which a part of light is screened by a screen element.
In the exemplifying optical device 201 illustrated in figures 2a-2c, the reflective surface 204 is asymmetric with respect to the first geometric plane 207 so that light reflected on the first side of the first geometric plane 207 is reflected more towards the first geometric plane 207 than light reflected on the second side of the first geometric plane 207. In figure 2c, the asymmetricity of the reflective surface 204 is expressed by that a profile 220 of the reflective surface 204 is steeper than a profile 221 of the reflective surface 204. The steeper-shaped profile 220 of the reflective surface 204 reflects light so that a desired cutoff line is produced in the distribution pattern of the light.
The exemplifying optical device 201 illustrated in figures 2a-2c is a single piece of transparent material that can be for example acrylic plastic, polycarbonate, optical silicone, glass, or some other suitable transparent material. Thus, the reflective surface 204 of the peripheral section 203 is a surface of the transparent material for providing total internal reflection “TIR” . It is also possible that an optical device according to an exemplifying and non-limiting embodiment comprises elements connected to each other. For example, the center section 202 and the peripheral section 203 can be manufactured as separate elements which are joined together. The optical device, or its elements, can be manufactured for example with mold casting.
As illustrated in figures 2a and 2b, the bottoms of the grooves on the second light egress surface 206 have a U-shaped cross-sectional profile and ridges between the grooves have a ∩-shaped cross-sectional profile. It is also possible that an optical device according to an exemplifying and non-limiting embodiment has grooves having a different shape, e.g. a V-shaped cross-sectional profile.
The light source 211 and the optical device 201 illustrated in figure 2c constitute functional elements of a low-beam headlight element according to an exemplifying and non-limiting embodiment. A frame structure of the low-beam headlight element configured to mechanically support the light source 211 and the optical device 201 is not shown.
Figures 3a, 3b, 3c, 3d, 3e, and 3f illustrate functionality of the light source 211 and the optical device 201. Figures 3a and 3b illustrate a light distribution pattern of the above-mentioned first part of the light that has penetrated the center section 202 of the optical device 201. Acurve 317a in figure 3a illustrates the light distribution pattern of the first part of the light on the first geometric plane 207 shown in figure 2c.Acurve 318a in figure 3a illustrates the light distribution pattern of the first part of the light on the second geometric plane that is the geometric section plane of the section view shown in figure 2c. The bulge 319 of the curve 318a manifests the fact that more light is directed downwards than upwards, which is advantageous in conjunction with a low-beam headlight application because a street or road gets illuminated. The functionality that more light is directed downwards than upwards is caused by the above-described asymmetricity of the light egress surface 205. Figure 3b shows the light distribution pattern of the first part of the light on a virtual screen that is parallel with the xy-plane of the coordinate system 299 shown in figure 2c. As shown in figure 3b, the upper rim of the light distribution pattern is straighter than the lower rim of the light distribution pattern.
Figures 3c and 3d illustrate a light distribution pattern of the above-mentioned second part of the light that has penetrated the peripheral section 203 of the optical device 201. Acurve 317b in figure 3c illustrates the light distribution pattern of the second part of the light on the first geometric plane 207 shown in figure 2c. A curve 318b in figure 3c illustrates the light distribution pattern of the second part of the light on the second geometric plane that is the geometric section plane of the section view shown in figure 2c. Figure 3d shows the light distribution pattern of the second part of the light on a virtual screen that is parallel with the xy-plane of the coordinate system 299 shown in figure 2c.
Figures 3e and 3f illustrate a superposition of the light distribution patterns illustrated in figures 3a-3d. Acurve 317c in figure 3e illustrates the light distribution pattern of the first and second parts of the light on the first geometric plane 207 shown in figure 2c. Acurve 318c in figure 3e illustrates the light distribution pattern of the first and second parts of the light on the second geometric plane that is the geometric section plane of the section view shown in figure 2c. Figure 3f shows the light distribution pattern of the first and second parts of the light on a virtual screen that is parallel with the xy-plane of the coordinate system 299 shown in figure 2c.
Figures 4a and 4b illustrate an optical device 401 according to an exemplifying and non-limiting embodiment. Figure 4c shows a light distribution pattern obtained with a light source and the optical device 401 on a virtual screen that is parallel with the xy-plane of the coordinate system 499 shown in figures 4a and 4b. The light source is not shown in figures 4a and 4b. The optical device 401 comprises a center section 402 that constitutes a lens portion configured to modify a distribution of a first part of light emitted by the light source. The lens portion has a first light egress surface 405 configured to refract the first part of the light. The optical device 401 comprises a peripheral section 403 that surrounds and is connected to the center section 402. The peripheral section 403 comprises a reflective surface configured to modify a distribution of a second part of the light emitted by the light source. The reflective surface is not shown in figures 4a and 4b, but the reflective surface of the optical device 401 can be like the reflective surface of the optical device 201 illustrated in figures 2a-2c. Furthermore, the peripheral section 403 comprises a second light egress surface 406 shaped to have grooves parallel to each other and configured to spread the second part of the light in a direction perpendicular to the grooves, i.e. in a direction parallel with the x-axis of the coordinate system 499.
The first light egress surface 405 of the lens portion is asymmetric with respect to a first geometric plane intersecting the top of the first light egress surface 405 and perpendicular to the grooves of the second light egress surface 406. In figures 4a and 4b, the first geometric plane is parallel with the xz-plane of the coordinate system 499. In figure 4b, the first geometric plane is depicted with a line and denoted with reference 407. In this exemplifying optical device 401, the first light egress surface 405 comprises a first part 408, a second part 409, and a third part 422. The first part 408 of the first light egress surface 405 is convex and the first part 408 is on a first side of the first geometric plane 407. The second part 209 of the first light egress surface 405 is convex and the second part 409 is on a second side of the first geometric plane 407. The first part 408 is more convex than the second part 409 to configure the first part 408 to refract light penetrating the first part 408 more towards the first geometric plane 407 than light penetrating the second part 409. The third part 422 of the first light egress surface 405 is convex and most of the third part 408 is on the first side of the first geometric plane 407. The first part 408 of the first light egress surface 405 is more convex than the third part 422 to configure the first part 408 to refract the light penetrating the first part 408 more towards the first geometric plane 407 than light penetrating the third part 422 of the first light egress surface 405. The horizontal part of the upper edge of the light distribution pattern shown in figure 4c is caused by light refraction in the first part 408 of the first light egress surface 405 whereas the right ascending part of the upper edge of the light distribution pattern is caused by light refraction in the third part 422 of the first light egress surface 405. Due to the asymmetric light distribution pattern shown in figure 4c, the optical device 401 is suitable for being a part of a low-beam headlight element of an automobile.
In the exemplifying optical device 401 illustrated in figures 4a and 4b, the first part 408 of the first light egress surface 405 is on a first side of a second geometric plane intersecting the top of the first light egress surface 405 and perpendicular to the first geometric plane 407. The third part 422 of the first light egress surface 405 is on a second side of the second geometric plane. In figures 4a and 4b, the second geometric plane is parallel with the yz-plane of the coordinate system 499. In figure 4b, the second geometric plane is depicted with a line and denoted with reference 423.
In an optical device according to an exemplifying and non-limiting embodiment, the first part 408 of the first light egress surface 405 covers from 20%to 30%of the total area of the first light egress surface 405, the second part 409 of the first light egress surface 405 covers from 40%to 60%of the total area of the first light egress surface 405, and the third part 422 of the first light egress surface 405 covers from 20%to 30%of the total area of the first light egress surface 405.
Figure 5 shows a schematic illustration of a vehicle 513 according to an exemplifying embodiment. The vehicle 513 comprises low-beam headlight elements according to an embodiment of the invention. One of the low-beam headlight elements is denoted with a reference 512. The low-beam headlight element comprises a light source 511 and an optical device 501 according to an exemplifying and non-limiting embodiment for modifying a distribution of light emitted by the light source 511. The optical device 501 can be for example like the optical device 201 illustrated in figures 2a-2c or like the optical device 401 illustrated in figures 4a and 4b. Each of the low-beam headlight elements is positioned in the vehicle 513 so that the grooves of the light egress surface of the peripheral section of the optical device 501 are vertical and the first part of the light egress surface of the lens portion of the optical device 501 is above the second part of the light egress surface of the lens portion when the vehicle 513 is on a horizontal surface 514 in a normal operating position of the vehicle. The exemplifying vehicle 513 shown in figure 5 is an automobile, but it is also possible that a vehicle according to an exemplifying embodiment is a motorcycle, amobile working machine, a railcar, or some other kind of vehicle.
The specific examples provided in the description given above should not be construed as limiting the scope and/or the applicability of the appended claims. Lists and groups of examples provided in the description given above are not exhaustive unless otherwise explicitly stated.

Claims (14)

  1. An optical device (201, 401, 501) for modifying light distribution, the optical device comprising:
    - a center section (202, 402) constituting a lens portion configured to modify a distribution of a first part of light emitted by a light source, and
    - a peripheral section (203, 403) surrounding and connected to the center section and comprising a reflective surface (204) configured to modify a distribution of a second part of the light emitted by the light source,
    wherein the lens portion has a first light egress surface (205, 405) , and the peripheral section has a second light egress surface (206, 406) shaped to have grooves parallel to each other and configured to spread the second part of the light in a direction perpendicular to the grooves, characterized in that the first light egress surface (205, 405) of the lens portion is asymmetric with respect to a first geometric plane (207, 407) intersecting a top of the first light egress surface (205) and perpendicular to the grooves so that:
    - a first part (208, 408) of the first light egress surface on a first side of the first geometric plane is convex,
    - a second part (209, 409) of the first light egress surface on a second side of the first geometric plane is convex, and
    - the first part (208, 408) of the first light egress surface is more convex than the second part (209, 409) of the first light egress surface to configure the first part of the first light egress surface to refract a part of the light penetrating the first part of the first light egress surface more towards the first geometric plane than a part of the light penetrating the second part of the first light egress surface.
  2. An optical device (401) according to claim 1, wherein the first light egress surface comprises a third part (422) most of it being on the first side of the first geometric plane (407) , the third part (422) of the first geometric plane being convex and the first part (408) of the first light egress surface being more convex than the third part (422) of the first light egress surface to configure the first part of the first light egress surface to refract the part of the light penetrating the first part of the first light egress surface more towards the first geometric plane than a part of the light penetrating the third part of the first light egress surface.
  3. An optical device (401) according to claim 2, wherein the first part (408) of the first light egress surface is on a first side of a second geometric plane (423) intersecting the top of the first light egress surface (405) and perpendicular to the first geometric plane (407) , and the third part (422) of the first light egress surface is on a second side of the second geometric plane.
  4. An optical device according to any one of claims 1-3, wherein the reflective surface is asymmetric with respect to the first geometric plane so that a part of the light reflected on the first side of the first geometric plane is reflected more towards the first geometric plane than a part of the light reflected on the second side of the first geometric plane.
  5. An optical device according to claim any one of claims 1-3, wherein the reflective surface (204) of the peripheral section is a surface of transparent material for providing total internal reflection.
  6. An optical device according to any one of claims 1-3, wherein bottoms of the grooves have a U-shaped cross-sectional profile.
  7. An optical device according to any one of claims 1-3, wherein ridges between the grooves have a∩-shaped cross-sectional profile.
  8. An optical device according to any one of claims 1-3, wherein a light ingress surface (210) of the lens portion is convex.
  9. An optical device according to any one of claims 1-3, wherein the optical device is a single piece of transparent material.
  10. An optical device according to claim 9, wherein the transparent material is one of following: acrylic plastic, polycarbonate, optical silicone, glass.
  11. A mold having a form suitable for manufacturing, by mold casting, a transparent piece constituting an optical device according to any one of claims 1-3.
  12. A low-beam headlight element (512) comprising:
    - a light source (211, 511) , and
    - an optical device (201, 401, 501) according to any one of claims 1-3 for modifying a distribution of light emitted by the light source.
  13. A vehicle (513) comprising at least one low-beam headlight element (512) according to claim 12, wherein the grooves are vertical and the first part of the first light egress surface is above the second part of the first light egress surface when the vehicle is on a horizontal surface in an operating position of the vehicle.
  14. A vehicle according to claim 13, wherein the vehicle is one of the following: an automobile, amotorcycle, amobile working machine, arailcar.
PCT/CN2023/139491 2022-12-19 2023-12-18 An optical device for modifying light distribution WO2024131722A1 (en)

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CN202211633196.9A CN118224558A (en) 2022-12-19 2022-12-19 Optical device and apparatus for changing light distribution
CN202211633196.9 2022-12-19

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WO2024131722A1 true WO2024131722A1 (en) 2024-06-27

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Citations (7)

* Cited by examiner, † Cited by third party
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CN201680258U (en) * 2010-03-23 2010-12-22 重庆科鹰电气有限公司 LED lighting unit and LED headlight light source employing same
CN102261618A (en) * 2010-05-28 2011-11-30 刘胜 LED (light emitting diode) automobile headlight optical lens
CN203823624U (en) * 2014-03-26 2014-09-10 华南理工大学 High-efficiency energy-saving vehicle LED (light emitting diode) dipped highlight structure
WO2015079890A1 (en) * 2013-11-29 2015-06-04 スタンレー電気株式会社 Vehicle lamp and lens body
DE102017213100A1 (en) * 2017-07-28 2019-01-31 Osram Gmbh TOTAL INTERNAL REFLECTION LINE (TIR-LENS), TIR-LENS ARRANGEMENT, LIGHTING SYSTEM AND HEADLIGHTS
EP2280214B1 (en) * 2008-05-28 2020-02-12 Koito Manufacturing Co., Ltd. Vehicular lighting equipment
US10641450B2 (en) * 2018-04-18 2020-05-05 Shutter Precision Co., Ltd. Optical lighting device of vehicles

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* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP2280214B1 (en) * 2008-05-28 2020-02-12 Koito Manufacturing Co., Ltd. Vehicular lighting equipment
CN201680258U (en) * 2010-03-23 2010-12-22 重庆科鹰电气有限公司 LED lighting unit and LED headlight light source employing same
CN102261618A (en) * 2010-05-28 2011-11-30 刘胜 LED (light emitting diode) automobile headlight optical lens
WO2015079890A1 (en) * 2013-11-29 2015-06-04 スタンレー電気株式会社 Vehicle lamp and lens body
CN203823624U (en) * 2014-03-26 2014-09-10 华南理工大学 High-efficiency energy-saving vehicle LED (light emitting diode) dipped highlight structure
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US10641450B2 (en) * 2018-04-18 2020-05-05 Shutter Precision Co., Ltd. Optical lighting device of vehicles

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