Patent Publication Number: US-11396991-B2

Title: Clear obelisk projector shield

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application claims the benefit of U.S. Provisional Patent Application No. 63/106,207 entitled “Clear Obelisk Projector Shield” and filed on Oct. 27, 2020, which is herein incorporated by reference in its entirety. 
    
    
     BACKGROUND OF THE INVENTION 
     1. Field 
     The disclosed embodiments relate generally to the field of lighting devices. More specifically, the disclosed embodiments relate to light modulation systems for a vehicle headlamp. 
     2. Description of the Related Art 
     Systems to control light exiting a vehicular lamp are known in the art. U.S. Pat. No. 10,655,819 to Na et al. discloses a vehicular lamp comprising a shield for blocking at least a portion of the light. U.S. Pat. No. 11,035,537 to Puech et al. discloses a luminous lighting module for an automotive vehicle which may form a cut-off beam. 
     SUMMARY 
     This summary is provided to introduce a selection of concepts in a simplified form that are further described below in the detailed description. This summary is not intended to identify key features or essential features of the claimed subject matter, nor is it intended to be used to limit the scope of the claimed subject matter. Other aspects and advantages of the invention will be apparent from the following detailed description of the embodiments and the accompanying drawing figures. 
     In an embodiment, a light modulation system configured to modulate light exiting a vehicular headlamp is provided. The system includes a light source, a reflector, a projector shield, and an outer lens. The reflector may be configured to reflect light from the light source in a specific direction. The projector shield includes a black metalized portion, which may be configured to form a cutoff light in the light projection. The projector shield includes a transparent optic protruding from the projector shield into the light projection. The transparent optic may redirect a portion of the light projection. The outer lens may be configured to invert the light after passing the projector shield. 
     In an embodiment, a projector shield for a vehicular headlamp is provided. The projector shield may include a black metalized portion and a clear metalized portion. The black metalized portion may be configured to block a portion of projected light. The clear metalized portion may be coupled to the black metalized portion. The projector shield may also include a clear obelisk optic, which may be coupled to the clear metalized portion. The clear obelisk optic may include a base protruding from the clear metalized portion. The clear obelisk optic may also include a tip protruding from the base. The based may be configured to allow a first portion of light to pass therethrough for projecting from the headlamp. The tip may be configured to refract a second portion of light for preventing the second portion of light from exiting the vehicular headlamp. 
     In an embodiment, a clear obelisk optic is provided. The clear obelisk optic may be a transparent optic extending from a projector shield of a headlamp. The transparent optic may include a tip portion and a base portion. The tip portion may have four sides angled inwardly. The base portion may be configured to support the tip portion. The tip portion and the base portion together may form an obelisk shape. The tip portion may be configured to redirect a first portion of light for preventing the first portion of light from exiting the headlamp. The base portion may be configured to allow a second portion of light to pass therethrough for projecting from the headlamp. 
    
    
     
       BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS 
       Illustrative embodiments are described in detail below with reference to the attached drawing figures, which are incorporated by reference herein and wherein: 
         FIG. 1  is a perspective view of a light modulation system of a vehicle headlamp including a projector shield having a clear obelisk optic, in an embodiment; 
         FIG. 2  is a close-up perspective view of the clear obelisk optic of  FIG. 1 ; 
         FIG. 3  is an up-close side view of the clear obelisk optic of  FIG. 1  showing exemplary light paths; 
         FIG. 4  shows a contour plot of light intensity imaged from a vehicle headlamp of  FIG. 6  having the clear obelisk optic of  FIG. 1 ; 
         FIG. 5A  shows a greyscale image of a light pattern resulting from a traditional vehicle headlamp; 
         FIG. 5B  shows a greyscale image of a light pattern resulting from a vehicle headlamp of  FIG. 6  having the clear obelisk optic of  FIG. 1 ; 
         FIG. 6  is a cross-sectional side view of a vehicle headlamp having the clear obelisk optic of  FIG. 1 , in an embodiment; 
         FIG. 7  illustrates a cross-section through the vehicle headlamp of  FIG. 6 ; 
         FIG. 8A  shows an illuminated road scene from a pair of traditional headlamps; and 
         FIG. 8B  shows an illuminated road scene from a pair of vehicle headlamps that each include the clear obelisk optic of  FIG. 1 . 
     
    
    
     The drawing figures do not limit the invention to the specific embodiments disclosed and described herein. The drawings are not necessarily to scale, emphasis instead being placed upon clearly illustrating the principles of the invention. 
     DETAILED DESCRIPTION 
     The following detailed description references the accompanying drawings that illustrate specific embodiments in which the invention can be practiced. The embodiments are intended to describe aspects of the invention in sufficient detail to enable those skilled in the art to practice the invention. Other embodiments can be utilized and changes can be made without departing from the scope of the invention. The following detailed description is, therefore, not to be taken in a limiting sense. The scope of the invention is defined only by the appended claims, along with the full scope of equivalents to which such claims are entitled. 
     In this description, references to “one embodiment”, “an embodiment”, or “embodiments” mean that the feature or features being referred to are included in at least one embodiment of the technology. Separate references to “one embodiment,” “an embodiment,” or “embodiments” in this description do not necessarily refer to the same embodiment and are also not mutually exclusive unless so stated and/or except as will be readily apparent to those skilled in the art from the description. For example, a feature, structure, act, etc. described in one embodiment may also be included in other embodiments, but is not necessarily included. Thus, the technology can include a variety of combinations and/or integrations of the embodiments described herein. 
     Vehicle headlamps project a light pattern to meet lighting performance objectives, including a range and an intensity of the light pattern. To avoid glare to an oncoming driver, light modulation systems including a fully opaque shield or a reflective shield (e.g., projector shield) are provided in the headlamp assembly to block a portion of light projected from the projector. The projector shield is configured to block light below a predetermined cutoff angle. The cutoff provides a light pattern in front of the vehicle that is projected downwardly towards the road. For example, the projector shield may be configured to provide a crisp cutoff at a zero degree up/down angle that extends directly in front of the vehicle (e.g., towards the horizon), such that the light pattern is restricted to downward angles below the cutoff. In addition, a specific point in the light pattern below the cutoff has a maximum intensity requirement to avoid glare to an oncoming driver. The specific point is mandated by the U.S. Department of Transportation, National Highway Traffic Safety Administration, and is known as the “legal test point”. The legal test point is located at 0.86 degrees down from the cutoff and 3.5 degrees left of center (0.86 D, 3.5 L). To achieve dimming of light below the maximum intensity requirement at the legal test point, traditional projector shields include a fully opaque protrusion corresponding to 0.86 D, 3.5 L. However, this design blocks a larger portion of light than what is necessary at the legal test point, making it difficult to provide sufficient intensity of light in areas around the legal test point. For example, the traditional shield protrusion blocks light between the legal test point and the cutoff, which creates a larger hole in the projected pattern of light than what is required. 
     Embodiments of the present disclosure provide a light modulation system that more accurately dims light at the legal test point without blocking light in neighboring regions of the light pattern. Rather than using an opaque projector shield protrusion, a transparent optic is used. The transparent optic is shaped like an obelisk and configured to selectively redirect light to provide a fuller light pattern without sacrificing greater reach of the pattern and while maintaining the legal test point requirement. 
       FIG. 1  is a perspective view of a light modulation system of a vehicle headlamp, including a projector shield  200  having a clear obelisk optic  100 . Projector shield  200  includes a black metalized portion  110  configured to block a portion of projected light and to provide a crisp cutoff of the light pattern. Black metalized portion  110  is for example a black metallized material in which a black plastic part (e.g., black polycarbonate) is formed by an injection molding process, followed by the part being coated with a metallic coating. Projector shield  200  also includes a clear metalized portion  120  in which a clear plastic part (e.g., clear polycarbonate) is formed by an injection molding process, followed by the part being coated with a metallic coating. Black metalized portion  110  and clear metalized portion  120  may be a single part formed with a two shot injection molding process (e.g., one shot with black plastic and one shot with clear plastic). In this manner, the first portion is still warm when the second shot is applied such that the two portions are bonded together. 
     In certain embodiments, clear obelisk optic  100  is formed as part of the clear plastic part during the injection molding process, then protected during the metallic coating step such that it remains uncoated and fully transparent. In this way, projector shield  200  is formed as a single monolithic piece. Alternatively, clear obelisk optic  100  may be a separate part made of any optically clear material such as glass or an optically clear plastic. In these embodiments, both the black metalized portion  110  and the clear metalized portion  120  are made of black plastic (e.g., in one shot) since the clear portion is no longer necessary to produce the clear obelisk optic  100 . The separate clear obelisk optic  100  may be attached to projector shield  200  using screw stakes, heat stakes, or an adhesive, for example. 
     Clear obelisk optic  100  protrudes from projector shield  200 , such that an upper portion of clear obelisk optic  100  extends above black metalized portion  110 . In some embodiments, clear obelisk optic  100  is a transparent optic protruding from the projector shield into the light projection. In this manner, a portion of light passing above black metalized portion  110  is redirected by at least a portion of clear obelisk optic  100 , as further described below in connection with  FIGS. 2 and 3 . An outer lens (e.g., outer lens  660  of  FIGS. 6 and 7 ) receives the light that passes by projector shield  200 , condenses the light, and flips the projected image over (e.g., upside down), such that the portion of the light pattern that is dimmed via the upwardly protruding clear obelisk optic  100  appears below the cutoff in the beam pattern (see  FIGS. 4 and 5 ). 
       FIG. 2  is a close-up perspective view of clear obelisk optic  100 . Clear obelisk optic  100  includes a tip  104  and a base  106 . Tip  104  is a top portion of optic  100  in which the four sides angle inwardly towards one another to form a pointed end  102 . The four angled sides of tip  104  are designated as an entry side  104 A, a near side  104 B, an exit side  104 C, and a far side  104 D (see  FIG. 2  and  FIG. 3 ). Entry side  104 A and exit side  104 C are oppositely faced along a longitudinal direction that is in line with the light path. Specifically, entry side  104 A faces towards incoming light, whereas exit side  104 C faces away from incoming light. Near side  104 B and far side  104 D are oppositely faced along a transverse direction that is perpendicular to the longitudinal direction and therefore not in line with the light path. An inward angle tilts entry side  104 A and exit side  104 C towards pointed end  102  at an angle between about thirty-five degrees and about fifty-five degrees. In some embodiments, the inward angle for entry side  104 A and exit side  104 C is about forty-five degrees. An inward angle tilts the transversely oriented sides  104 B,  104 D towards pointed end  102  at an angle between about three degrees and about forty-five degrees. 
     Base  106  is a bottom portion of clear obelisk optic  100  configured to support tip  104 . The four sides of base  106  may be vertical, or nearly vertical and having a slight inward angle towards one another. Base  106  is configured to partially protrude upwardly above a clear surface  108 . Clear surface  108  is configured to be substantially parallel with a top surface of projector shield  200  (see  FIG. 1 ). Although the different sections of clear obelisk optic  100  are described separately herein, it should be appreciated that clear obelisk optic  100  is, in embodiments, a single piece of material (e.g., formed with a single injection molding shot). 
       FIG. 3  is an up-close side view of clear obelisk optic  100  showing a first light path  131 , a second light path  132 , and a third light path  133 . As illustrated in  FIG. 3 , the light paths  131 ,  132 ,  133  are traveling from left to right as they encounter clear obelisk optic  100 . A first light path  131  enters clear obelisk optic  100  at tip  104  through entry side  104 A and is refracted downwards into base  106  at an angle such that the light reflects internally off of a distal side  106 C of base  106 . First light path  131 , therefore, remains trapped in clear obelisk optic  100  due to total-internal reflection (TIR). In this manner, first light path  131  is effectively blocked from traveling beyond clear obelisk optic  100  such that first light path  131  fails to reach an outer lens and fails to be projected from a headlamp in front of a vehicle. In other words, first light path  131  is refracted by tip  104 , such that the refracted light is prevented from exiting the vehicular headlamp. 
     A second light path  132  enters clear obelisk optic  100  at tip  104  through entry side  104 A and is refracted downwards into base  106  at such an angle that the light passes through the distal side  106 C of base  106 . For example, the downward angle of second light path  132  through clear obelisk optic  100  is less than that of first light path  131  due to the angles at which the light paths reach the entry side  104 A. Upon exiting clear obelisk optic  100 , second light path  132  is directed downwardly such that it misses an outer lens  660  and is instead absorbed by a lens holder  662  (see  FIGS. 6 and 7 ). Therefore, second light path  132  is also effectively blocked as it fails to reach the outer lens and is not projected from the vehicle headlamp. In other words, second light path  132  is refracted by tip  104 , such that the refracted light is prevented from exiting the vehicular headlamp. 
     A third light path  133  enters clear obelisk optic  100  at base  106  and is only marginally refracted such that third light path  133  enters the base  106  on a proximal side  106 A and exits on the distal side  106 C at an angle that deviates only slightly from the entry angle. Therefore, third light path  133  reaches the outer lens and is projected from the vehicle headlamp. In this manner, light that enters tip  104  is effectively prevented from exiting the vehicle headlamp, while light that enters base  106  effectively permits light to be projected from the vehicle headlamp. Thus, clear obelisk optic  100  may be used to substantially dim light at the legal test point via tip  104 , and to substantially illuminate regions outside of the legal test point, in particular the region between the cutoff and the legal test point. In other words, the result of using clear obelisk optic  100  in projector shield  200  is a small spot of reduced light intensity in the projected light pattern, as illustrated in  FIG. 4 . 
     It is contemplated that clear obelisk optic  100  may be a transparent optic. Transparent optic may similarly include a base portion and a tip portion that do not form a substantially obelisk shape, but any other shape which may similarly refract light bidirectionally. For example, transparent optic may be elliptically shaped, including a base portion configured to allow the passage of light therethrough and a tip portion configured to refract light, such that the refracted light does not exit the vehicular headlamp. In another example, transparent optic may be pyramidally shaped, including a base portion configured to allow the passage of light therethrough and a tip portion configured to refract light, such that the refracted light does not exit the vehicular headlamp. It is contemplated that the transparent optic may comprise any shape which includes a base portion and a tip portion, said base portion and tip portion configured to alternatively refract light to modulate the light projection from a vehicular headlamp. 
       FIG. 4  shows a contour plot  400  of light intensity imaged from vehicle headlamp  600  of  FIG. 6  having clear obelisk optic  100 . The rainbow color scale on  FIG. 4  shows a range of light intensity from a low intensity of about 63 cd represented with dark blue, to a high light intensity of about 40,000 cd, represented in red. A legal test point  440  is plotted at −0.86 degrees down and 3.5 degrees left of center (0.86 D, 3.5 L). The region immediately around legal test point  440 , which is labeled region “A” in  FIG. 4 , has a substantially reduced light intensity (e.g., approximately 2,500 cd) compared to that of surrounding regions of the light pattern. For example, the area above Region A, which is labeled region “B” in  FIG. 4 , has a comparatively higher light intensity (e.g., approximately 25,000 cd). A cutoff line  442  shows where light intensity is cut off via black metalized portion  110  such that the region immediately above cutoff line  442 , which is labeled region “C” in  FIG. 4 , has very low levels of light intensity (e.g., approximately 250 cd). 
     The A, B, and C regions illustrated in  FIG. 4  correspond with portions of clear obelisk optic  100  and black metalized portion  110  from  FIG. 3 . For example, region A corresponds with light traveling into an upper portion of tip  104  (labeled “A” in  FIG. 3 ) that remains trapped in clear obelisk optic  100  due to TIR, such as first light path  131  of  FIG. 3 . Region B in  FIG. 4  corresponds with light passing through base  106  (labeled “B” in  FIG. 3 ), such as third light path  133  of  FIG. 3 . Region C in  FIG. 4  corresponds with light that passes through tip  104 , refracts downwardly, and exits clear obelisk optic  100  on a downward trajectory angled below black metalized portion  110  (labeled “C” in  FIG. 3 ), such as second light path  132  of  FIG. 3 . 
     Illuminating region B with a relatively high light intensity (e.g., approximately 25,000 cd) compared to a relatively dim light intensity in region A (e.g., approximately 2,500 cd) is not possible using a traditional opaque shield protrusion, which substantially dims light in region B similar to that of region A. Minor light leak/bleed allows enough light to reach region A for meeting minimum requirements set by Federal Motor Vehicle Safety Standards (FMVSS). 
       FIGS. 5A and 5B  show exemplary light patterns from a vehicle headlamp. In  FIG. 5A , a greyscale image  500  shows a light pattern resulting from a traditional vehicle headlamp, having a traditional opaque protrusion extending from the cutoff shield, to block light at legal test point  440  (region A) and at the area between legal test point  440  and cutoff line  442  (region B). In  FIG. 5B , a greyscale image  510  shows a light pattern resulting from vehicle headlamp  600  of  FIG. 6  having clear obelisk optic  100 , which protrudes from the cutoff shield to dim light around legal test point  440  (region A) but not in the area between legal test point  440  and cutoff line  442  (region B). Region A in  FIG. 5B  is dimmed (to about 2,500 cd), whereas region A in  FIG. 5A  is effectively blocked (to about 500 cd). Region B in  FIG. 5B  is substantially illuminated like other portions of the illuminated light pattern (to about 25,000 cd), whereas in  FIG. 5A , region B is effectively blocked (to about 500 cd). 
       FIG. 6  is a cross-sectional side view of a vehicle headlamp  600 .  FIG. 7  illustrates a cross-section through vehicle headlamp  600  corresponding with the view shown in  FIG. 6 .  FIGS. 6 and 7  are best viewed together with the following description. 
     A light source  670  provides light for projecting from vehicle headlamp  600 . Light source  670  is, for example, a light-emitting diode (LED) or an array of LEDs electrically coupled with a printed circuit board  672 . A heat pipe  684  is thermally coupled with light source  670  for removing heat produced by light source  670 . A heat sink  680  is thermally coupled with heat pipe  684  for dispersing heat to the surrounding environment. For example, heat sink  680  may include a series of fins for transferring heat to ambient air via convection. 
     Light from light source  670  is directed upwards towards a reflector  650 , which reflects the light towards outer lens  660 . Lens holder  662  holds lens  660  in place and is black to absorb any stray light. Black metalized portion  110  blocks a lower portion of light reflected off of reflector  650 . Clear obelisk optic  100  protrudes above black metalized portion  110  to redirect a portion of light as explained above in connection with  FIGS. 3 and 4 . Outer lens  660  condenses the light and flips the image upside down such that the blocked light is above the illuminated portion in the projected light pattern (as shown in  FIG. 5B ). 
     An optional motor  690  enables rotation of projector shield  200  for moving it out of the light path to provide a high beam light pattern with no cutoff. It should be noted that clear obelisk optic  100  may be used in a bi-functional headlamp (e.g., providing a low beam and a high beam), such as vehicle headlamp  600 , or simply with any low beam headlamp. 
       FIGS. 8A and 8B  show exemplary road scenes illuminated with a pair of vehicle headlamps. In  FIG. 8A , a road scene  800  shows an illuminated road scene from a pair of traditional headlamps. Since each of the traditional headlamps has an opaque protrusion extending from the cutoff shield to block light at legal test point  440  (region A in  FIG. 5A ), light is also blocked at the area between legal test point  440  and cutoff line  442  (region B in  FIG. 5A ). As shown in the highlighted area  802  of  FIG. 8A , this results in the pair of dimmed portions (from the pair of vehicle headlamps) being noticeably darker due to a “hole” in the light pattern where the light is effectively blocked and no illumination on the road is present. 
     In contrast,  FIG. 8B  shows a road scene  810  illuminated with a pair of vehicle headlamps (e.g., headlamp  600 ) that each include clear obelisk optic  100  protruding from the cutoff shield, which produces a light pattern like that shown in  FIG. 5B  where light is dimmed around legal test point  440  (region A in  FIG. 5B ) but not in the area between legal test point  440  and cutoff line  442  (region B in  FIG. 5B ). As shown in the highlighted area  812  of  FIG. 8B , this results in the pair of dimmed portions (from the pair of vehicle headlamps) being less noticeable compared to  FIG. 8A  since there is no hole in the light pattern. 
     Features described above as well as those claimed below may be combined in various ways without departing from the scope hereof. The following examples illustrate some possible, non-limiting combinations: 
     (A1) A light modulation system is configured to modulate a light projection exiting a vehicular headlamp, the system includes a light source, a reflector configured to reflect light from the light source in a specific direction, a projector shield which includes a black metalized portion configured to form a cutoff line in the light projection, a transparent optic protruding from the projector shield into the light project, the transparent optic configured to redirect a portion of the light projection, and an outer lens configured to invert the light after passing the projector shield. 
     (A2) For the light modulation system denoted as (A1), the transparent optic may include a base that may be configured to allow the passage of light therethrough, and a tip that may be configured to refract light preventing a refracted light from exiting the vehicular headlamp. 
     (A3) For the light modulation system denoted as (A1) or (A2), the tip may include four sides angled inwardly, said sides may be configured to refract light towards the base. 
     (A4) For the light modulation system denoted as any of (A1) through (A3), the system may include a motor operatively connected to the projector shield, the motor may be configured to adjust a position of the projector shield therein removing the cutoff line from the light projection. 
     (A5) For the light modulation system denoted as any of (A1) through (A4), the transparent optic may be one of a clear plastic or a glass. 
     (A6) For the light modulation system denoted as any of (A1) through (A5), the transparent optic may cause a first area within the light projection to be dimmer than other areas in the light projection not affected by the transparent optic. 
     (A7) For the light modulation system denoted as any of (A1) through (A6), the projector shield may include a clear metalized portion aligned with the black metalized portion. 
     (A8) For the light modulation system denoted as any of (A1) through (A7), the clear metalized portion and the transparent optic may be formed of one piece of material and the transparent optic may be an extension of the clear metalized portion that may be configured to extend into the light projection. 
     (A9) For the light modulation system denoted as any of (A1) through (A8), the system may include a lens holder that mechanically couples the outer lens to the light modulation system, the lens holder may be configured to absorb the refracted light. 
     (A10) For the light modulation system denoted as any of (A1) through (A9), the transparent optic may cause a second area within the light projection to be substantially as bright as the other areas in the light projection, said second area may be located between the first area and the cutoff line. 
     (B1) A projector shield for a vehicular headlamp includes a black metalized portion configured to block a portion of projected light, a clear metalized portion coupled to the black metalized portion, and a clear obelisk optic coupled to the clear metalized portion, the clear obelisk optic includes a base protruding from the clear metalized portion, and a tip protruding from the base, the base is configured to allow a first portion of light to pass therethrough for projecting from the headlamp, and the tip is configured to refract a second portion of light for preventing the second portion of light from exiting the vehicular headlamp. 
     (B2) For the projector shield denoted as (B1), the clear obelisk optic may include a clear surface connected to the base opposite the tip, the clear surface may be coupled to the clear metalized portion. 
     (B3) For the projector shield denoted as (B1) or (B2), the clear obelisk optic may be an extension of the clear metalized portion. 
     (B4) For the projector shield denoted as any of (B1) through (B3), the base and the tip of the clear obelisk optic may form an obelisk shape. 
     (B5) For the projector shield denoted as any of (B1) through (B4), the clear obelisk optic may be one of a clear plastic or a glass. 
     (C1) A clear obelisk optic includes a transparent optic extending from a projector shield of a headlamp, the transparent optic includes a tip portion having four sides angled inwardly and a base portion configured to support the tip portion, the tip portion and the base portion together form an obelisk shape and the tip portion is configured to redirect a first portion of light for preventing the first portion of light from exiting the headlamp and the base portion is configured to allow a second portion of light to pass therethrough for projecting from the headlamp. 
     (C2) For the clear obelisk optic denoted as (C1), the four sides of the tip portion may be angled inwardly at an angle between thirty-five degrees to fifty-five degrees. 
     (C3) For the clear obelisk optic denoted as (C1) or (C2), the clear obelisk optic may be made of a clear plastic. 
     (C4) For the clear obelisk optic denoted as any of (C1) through (C3), the clear obelisk optic may be made of glass. 
     (C5) For the clear obelisk optic denoted as any of (C1) through (C4), the clear obelisk optic may include a clear surface coupled to a clear metalized portion of the projector shield. 
     Many different arrangements of the various components depicted, as well as components not shown, are possible without departing from the spirit and scope of what is claimed herein. Embodiments have been described with the intent to be illustrative rather than restrictive. Alternative embodiments will become apparent to those skilled in the art that do not depart from what is disclosed. A skilled artisan may develop alternative means of implementing the aforementioned improvements without departing from what is claimed. 
     It will be understood that certain features and subcombinations are of utility and may be employed without reference to other features and subcombinations and are contemplated within the scope of the claims. Not all steps listed in the various figures need be carried out in the specific order described.