Light device

A lighting device includes a housing, the housing comprising an opening. The lighting device also comprises a lens operably disposed in the opening, the lens having an outer viewable face and an opposed inner face, the lens comprising an integrally formed axially-extending light guide, the light guide comprising a light inlet end, a light outlet comprising a portion of the outer viewable face, and a light transmission portion, the light transmission portion comprising a light reflecting structure disposed on the inner face. The lighting device also includes a light source, the light guide configured to receive light rays from the light source into the light inlet end, transmit the rays via internal reflectance along light transmission portion to the light reflecting structures where they are reflected outwardly away from the lighting device in a principal direction through the outer viewable face.

TECHNICAL FIELD

The invention relates to a new light device for motor vehicles comprising an LED light source and an elongated light guide.

BACKGROUND OF THE INVENTION

In the field of lighting technology, light emitting diodes, referred to with the abbreviation LED, are frequently used as a light source instead of the conventional halogen bulbs. Among the lights of motor vehicles light guides occupy a special position as their elongated shape makes them especially suitable to create light lines positioned along the outline of headlights, or separately to create warning lights, e.g. positional, brake, indicator, or daily orientation lights. At present, light guides often fulfill signal light functions subject to higher requirements for the luminous flux, e.g. the day-time running lamps in headlights and the rear brake and direction indication lights in the rear lamps. Sometimes they are used where a bright, uniform appearance for the side repeater, which is incorporated into the side mirror, is requested.

The document U.S. Pat. No. 7,699,511 describes a turn lamp with a base housing; a light source unit incorporated with a light source, e.g. LED, and housed in the base housing; an inner housing has a long and solid light guide; and a lens cover covers the base housing. A diffused reflection generator is structured such that light from the light source leaks out from the light guide. The light source is arranged at a longitudinal end portion of the light guide. The base housing has a body portion that is integrally molded from a non-translucent resin material. A disadvantage of this design is that it requires a relatively thick packaging space to accommodate the lens cover and several light sources to achieve a uniform appearance.

The document EP1657111 discloses a lamp with an optical fiber, including a set of deflecting structures, which deflects light that falls on the structures in such a manner that the light comes out of a front side of the optical fiber. A set of optically operative structures is arranged over a length of the optical fiber and a part of the remaining light is emitted in angular areas extending transverse to a driving direction.

A disadvantage of this design is that it still requires a secondary lens to act as an outer lens to protect the light guide. This increases the required packaging space and requires an additional molded part for the exterior lens.

The document US20090284365 discloses a light module having visible-light emitting light source, e.g. LED, coupled to one of a set of light guiding elements and an infrared light emitting light source coupled to one of the light guiding elements. A major portion of a longitudinal extension between ends and opposite ends, respectively of the light guiding elements, follows an outer contour. The light guiding elements emit light along the major portion of the longitudinal extensions. The light sources are coupled to the light guiding elements.

As shown in FIG. 2b, this design does not include any method to protect the optical elements from the environment and will require an additional outer lens to protect the optical surfaces. Additionally, this design does not address a method for extracting light from the guides.

The technical solutions mentioned above all require an exterior lens to protect the optical system, generally a light guide. This requires significant packaging space for the lamp, which is not available in certain applications. Many lamps, particularly; side repeaters, side mounter turn signals, and applique lamps; have very narrow packaging space requirements, which makes it difficult and in some cases not possible to fit a light guide and an outer lens with an air gap between. In the prior designs, a number of optical systems are known where an indirect reflector is used behind either a grained/textured or volumetric-diffusing lens with a narrow area in between individual reflector segments. Alternatively, a light guide may be used in place of an indirect reflector. For a truly homogeneous appearance, two diffuser lenses are needed. One of the diffusers may also be the outer lens. This type of design is also undesirable for the applications mentioned because it requires too much package space because space is required for multiple lenses as well as clearance spaces to account for variations in assembly and molding.

Therefore, it is very desirable to provide a light device that overcomes the shortcomings and disadvantages of the previous light designs noted above.

SUMMARY OF THE INVENTION

A lighting device, including a vehicular lighting device, is disclosed. The lighting device includes a housing, the housing comprising an opening. The lighting device also comprises a lens operably disposed in the opening, the lens having an outer viewable face and an opposed inner face, the lens comprising an integrally formed axially-extending light guide, the light guide comprising a light inlet end, a light outlet comprising a portion of the outer viewable face, and a light transmission portion, the light transmission portion comprising a light reflecting structure disposed on the inner face. The lighting device also includes a light source, the light guide configured to receive light rays from the light source into the light inlet end, transmit the rays via internal reflectance along light transmission portion to the light reflecting structures where they are reflected outwardly away from the lighting device in a principal direction through the outer viewable face.

The present light device eliminates the shortcomings and disadvantages of the prior art light devices in two principle ways. Previous designs require separately molded interior light guide part and an exterior lens part for either light manipulation and/or protecting the interior light guide from environmental factors. First, the present invention advantageously eliminates the need for a separately molded exterior lens and interior light guide and by extension eliminates the need for a separate mold tool and molding operation. Second, the present invention advantageously significantly reduces the amount of packaging space needed for a light guide function by combining the outer lens and the light guide into a single item. A traditional system would require 2-3 mm for the outer lens and 4-10 mm for the light guide with at least 2-5 mm of clearance space for a total thickness of 8-18 mm. In one embodiment, the present light device would eliminate the clearance space and combine the lens thicknesses giving a total thickness of 4-10 mm, and in certain embodiments 4 mm to less than 8 mm, and 4 mm to 7.5 mm.

DETAILED DESCRIPTION

Referring now to the Figures, where the invention will be described with reference to specific embodiments, without limiting same, the light or lighting device100in accordance with the invention is explained with the use of drawings. The light device100may be employed in any suitable application or design, including as a light device100for various vehicles or in various vehicular applications, particularly in all manner of automotive vehicles. In one embodiment, the lighting device100comprises a vehicular exterior lighting device or a vehicular interior lighting device. In one embodiment, a vehicular exterior lighting device comprises a side mirror light, a tail light, a parking light, a running light, or a head light.FIG. 1shows a longitudinal section view of the light guide2in which the exit face or surface4for emission of light rays17is combined with outer lens7. The ends of the lens7/light guide2as well as the light source1and optical in-coupling area or light inlet end3are hidden behind an outer cover or housing8, typically comprising a fascia or a bezel. In one embodiment, the outer lens7is curved or flat, and in another embodiment the lens is clear or colored. The cover or housing8is opaque in the arrangement shown but may also be translucent or transparent. The housing comprises an opening19and the lens7/guide2is operably disposed in the opening. Other backing structure elements9of the lamp or vehicle, such as sheet metal or other components such as those that define an inner cover, may optionally reside behind the light guide2. The light guide2may be made from any suitable optical lightguide material, and in certain embodiments is made of either polycarbonate (PC) or polymethyl methacrylate (PMMA), preferably of crystal quality, due to the favorable optical and mechanical properties of these materials.

FIG. 2shows a cross section view of the parts of the light guide2with the outer lens7. The upper14and lower15portions of the lens are hidden behind the opaque cover8and would act as the attachment features for the light guide2.FIG. 2shows an application using vibration or infra-welding to provide attachments16as weld joints, but any other suitable attachment scheme or fastening mechanism to provide attachments16for attaching the light guide2, such as various fasteners, glues, or hot-plate welting would be acceptable. Other backing structure elements9of the lamp or vehicle, including interior mirror mechanical elements in this arrangement, reside behind the lamp with the bulk of the light guide2in the packaging space10or cavity between them.

FIGS. 3A and 3Bshow a plurality of prismatic faces5disposed on the back side of the light guide2. These prismatic faces5are disposed between totally internal reflecting areas6on the back of the light guide2and eject light from them outwardly from the light guide through the exit face4or surface. Light from the source1enters through the in-coupling area3into the light guide2.

FIGS. 4A and 4Bshow the light guide2, where the end11of longitudinal section is angled to direct light into a photometric pattern in a different direction than the primary ejection direction from the prisms5out of the primary exit face4.

FIG. 5shows a front view of an embodiment of a side mirror application12. From this perspective the emitting exit face4of the light guide2is visible through the outer cover8. The angled end11directs light rays18inwardly away from an observer of the exit face4and light rays17from this perspective.

FIG. 6shows a longitudinal section view of an alternate embodiment of a rear lamp13in which the outer lens7comprises and is flush with the light emitting exit surface4of the light guide2. In this embodiment, the outer lens7has a surface area that is greater than and extends beyond the surface area of the light emitting exit surface4portion of the light guide2. In the embodiment ofFIGS. 6 and 7, the surface and surface area of the outer lens7extends or projects longitudinally beyond the light emitting exit surface4portion and opposing ends31,32of the light guide2in the form of longitudinal projections33,34as shown inFIG. 6. The surface and surface area of the outer lens7also extends or projects laterally upwardly and downwardly beyond the light emitting exit surface4portion and upper and lower projections37,38as shown inFIG. 7. The projections33,34,37,38may extend beyond the light emitting exit surface4by any desired amount or predetermined distance. The predetermined distance of projections33,34,37,38may vary depending on the light device, and may be the same, or may each be different, in any combination, and the predetermined distance of one or more of projections33,34,37,38may be zero as long as the predetermined distance of at least one is non-zero. In one embodiment, the exit surface4may comprises a smooth surface or a textured surface, or a combination thereof.

Referring again toFIG. 6, light rays17from light source1, an LED in this arrangement, enters light guide2through in-coupling optics3. Prismatic faces5on back side of the light guide2. These prismatic faces5are disposed between total internal light reflecting areas6and direct light in light guide2through the exit face4. In this arrangement the other backing structure elements9of the lamp are attached directly to the lens7. In this arrangement the cover8only covers the light source1and leaves most of the lens7uncovered. The angled end11in this arrangement is used to send light rays19in a direction back towards the light source1.

FIG. 7shows a cross section view of arrangement of a rear lamp13. Emitting exit face4is flush to the outer lens7and attaches directly to the other backing structure elements9of the lighting device or a vehicle. Any suitable method or mechanism for attachment such as fasteners and vibration welding and the other methods and fastener mechanisms described herein can be used to attach the other backing structure elements9and outer lens7.

FIG. 1andFIG. 5show an embodiment of a for a side repeater12(sometimes referred to as a side mirror turn signal) light device100of motor vehicles comprising an elongated light guide2and a light source1, LED in this arrangement, positioned in the entry part3of the light guide2for emitting the light beam into the light guide2. The light guide2also comprises exit face4and a reflective inner face, which in one embodiment comprises prismatic face5, oriented along its length. Exit face4constituting an exit surface for the light rays propagated in the light guide2.

The reflective inner face5, such as prismatic face5, is disposed opposite to the exit face4and comprises a total internal reflection surface6, which are therefore provided with light reflecting structure40or elements, such as prisms, and walls to send out uniform light rays17forward and outboard of the vehicle through the exit face4and light rays18outwardly in a direction different than the direction of light rays17through angled end11for legal functionality. In one embodiment, the light reflecting structure40or elements, such as prisms comprises a plurality of axially-spaced prism structures disposed along the light transmission portion. The light guide2is incorporated in the lens7with the light emitting face4disposed in an opening19in the opaque cover8. By combining the lens7and light guide2the packaging space10between light guide2and other elements9, including the interior mechanical mirror components in this arrangement, of lighting device100can be very thin. In one embodiment, the light guide2comprises a tapered portion41,43that tapers axially and upwardly away from the inner face to the light emitting angled end and opposed end, respectively. In one embodiment, the light device100would reduce or eliminate the clearance space and combine the lens thicknesses giving a predetermined total thickness of the light device100from the face of the lens to rear of the backing structure of 4-10 mm, and in certain embodiments 4 mm to less than 8 mm, and 4 mm to 7.5 mm.

FIGS. 4A and 4Bshow a light device100comprising light guide2with angled end11to direct light rays18into a photometric pattern. Angled end11of light guide2is situated near to an opaque cover8to emit light in a direction different than the primary direction of emission of light rays17. In one embodiment, the angled end11is chamfered or tapered to direct light in a desired direction and may have any suitable radius of curvature or other outwardly convex curved shape, and in one embodiment may include a radius of curvature of between 0.3 and 2 mm to adjust the light distribution in the secondary direction. The angled end11may also be used to reduce a visible gap between body side lamps and deck lid lamps by running light guides2all the way to the edge of the lens7surface.

FIGS. 6 and 7show another embodiment of light device100as part of the outer lens of a rear lamp13. The principle difference between the outer lens of a rear lamp13and the side mirror or repeater12is that in the outer lens of a rear lamp13the lens7and the emitting exit face4of the light guide2are flush and the lens7is attached directly to the other elements9of the lamp, comprising an exterior housing in this embodiment. The opaque cover8in this embodiment is only blocking direct (e.g. non-reflected) light rays from1and can be attached to the other elements9and/or lens7. Additionally lens7in the outer lens of a rear lamp13is significantly flatter than the side mirror or repeater12. Alternate embodiments can adjust the curvature of the outer lens7to accommodate the stylistic and mechanical requirements of the lamp design of light device100.

For both the side mirror or repeater12and the outer lens of a rear lamp13, the light guide2is made of a transparent polymer, polycarbonate (PC) or polymethyl methacrylate (PMMA), preferably of crystal quality due to the favorable optical and mechanical properties of these materials. Part of the light guide2is molded as part of the outer lens7comprising exit face4and angled exit face11. The lens7is joined to the light guide2and together they form an integrally joined, optically transmissive unit, such that the light rays transmitted within the light guide2is transmitted internally directly through the lens. In one embodiment the lens7is integrally formed or molded with light guide2into a single, integral unit. In another embodiment, the lens7is insert molded or co-molded with light guide2, or vice versa, to form a single, integral co-molded unit. In yet another embodiment, the lens7is formed separately from the light guide2and the two are joined together by an optically transmissive joint. The optically transmissive joint may be any suitable joint, including a glue joint with a refractive index matching glue, or various types of weld joints. The joined lens7and light guide2is a more optically efficient system than a two-part system as described in the background due to fewer Fresnel losses and eliminates an entire molded part and associated tooling.

Light source1is coupled to a control unit to provide desired predetermined light output characteristics of the output light spot and a predetermined output light area, wherein the light source1, or plurality of sources1, are alternately or jointly controllable by the control unit, and are configured to provide daily lighting and/or indicator light and/or rear contour light and/or front contour light.