Lamp assembly having variable focus and directionality

[0001] 1. Field of the Invention

[0002] This invention relates generally to lighting assemblies for illuminating the interior passenger compartment of a motor vehicle, and more specifically toward a lighting assembly which is adjustable between flood and spot lighting conditions and also directionally adjustable.

[0003] 2. Related Art

[0004] Lighting assemblies are well known for use in motor vehicle interior cabins, trunks, engine compartments, and other environments where light is needed. Such lighting assemblies provide direct lighting, indirect lighting, and backlighting, among other applications, and have become smaller, more efficient, more durable and longer lasting. Typically, indirect, or general illumination lighting is accomplished by dome lamp assemblies or other lighting device which disperses light over a large area. This is in contrast to direct or task lighting applications, such as map or reading lights, where light from the light source is focused in a relatively narrow area.

[0005] Typically, the flood and spot lighting features are accomplished by separate lighting assemblies dedicated to each function. For example, U.S. Pat. No. 6,502,969 to Logel et al. discloses a multi-function lighting assembly in which separate lighting devices are required to accomplish the flood and spot lighting functions. Although Logel uses a unitary structure to accomplish all of these functions, the overall assembly is nevertheless large, cumbersome and expensive to manufacture.

[0006] Variable focus lighting assemblies have been proposed with limited functionality. For example, U.S. Pat. No. 5,070,434 to Suman et al. discloses an incandescent bulb with a reflector that can be repositioned to focus and unfocus the light path. The Suman et al. light assembly is deficient however, in that the light beam pattern is directionally adjustable only when in the spot lighting condition; it is immobile in the flood lighting condition. Furthermore, multiple user inputs are required to turn the light assembly on and off, and to refocus the light beam pattern. These multiple inputs can present an inconvenience, as well as a distraction to the driver.

[0007] Accordingly, there exists a need for an improved lighting assembly which is adjustable between flood and spot lighting conditions and which is easier to operate, less distracting for a driver, and fully directionally adjustable in both flood and spot lighting conditions.

[0008] The subject invention overcomes the disadvantages and shortcomings of the prior art by providing a lighting assembly which is adjustable between flood and spot lighting conditions for selectively illuminated the interior passenger compartment of a motor vehicle. The lighting assembly comprises a housing for attaching the assembly to a supporting member in an interior compartment of the motor vehicle. A light source is carried in the housing for projecting light along a light path. A power input is operatively connected to the light source for selectively energizing the light source. An optical member is positioned so as to influence the light path. The optical member is moveable between a flood position wherein light from the light source is dispersed over a generally wide area within the passenger compartment and a spot position wherein light from the light source is focused over a generally narrow area within the passenger compartment. A switch is responsive to movement of the optical member for automatically interrupting the operative connection between the power input and the light source when the optical member is moved to the flood position, and automatically restoring the operative connection when the optical member is moved to the spot position so as to energize the light source and thereby illuminate the passenger compartment with a focused beam of light. Thus, the single user input action of refocusing the light source from flood to spot lighting conditions automatically energizes the light source so as to provide spot lighting functionality. Conversely, returning the optical member to its flood position automatically de-energizes the light source.

[0009] In the preferred embodiment of the invention, a separate lighting control circuit is provided which is responsive to an override signal for activating the light source independently of the switch when the optical member is in its flood position. For example, the lighting control circuit might be responsive to a door switch or an interior illumination control switch so that the override signal powers the light source together with other general interior illumination features during occupant entrance and exit.

[0010] According to another aspect of the subject invention, the lighting assembly is adjustable between flood and spot lighting conditions for selectively illuminating the interior passenger compartment of a motor vehicle. The lighting assembly comprises a housing for attaching the assembly to a supporting member in an interior compartment. A light source is carried in the housing for projecting light along a light path. A power input is operatively connected to the light source for selectively energizing the light source. An optical member is disposed in the light path and is moveable between a flood position wherein light from the light source is influenced by the optical member to disperse the light over a generally wide area within the passenger compartment, and a spot position wherein light from the light source is influenced by the optical member to focus over a generally narrow area within the passenger compartment. The optical member is disposed within the housing for orbital movement in both of its flood and spot positions while the light source remains energized. Thus, the light source is directionally adjustable in its spot position, which may be useful for map reading and other task oriented activities, and is also directionally adjustable in its flood lighting condition so that general illumination can be directed toward certain areas or directed away from other areas. For example, it may be desirable to direct flood lighting away from a sleeping child or to direct flood lighting toward ingress/egress areas.

[0011] According to yet another aspect of the invention, a method is provided for selectively illuminating the interior passenger compartment of a motor vehicle between flood and spot lighting conditions. The method comprises the steps of supporting a light source in an interior compartment, projecting light from the light source along a light path, selectively varying the focus of the light path between a flood condition, wherein the light is dispersed over a relatively wide area in the passenger compartment and a spot condition wherein light is focused over a relatively narrow area within the passenger compartment, automatically energizing the light source in response to the step of varying the focus of the light path to the spot condition, and automatically de-energizing the light source in response to the step of varying the focus of the light path to the flood condition.

[0012] Accordingly, these various aspects of the subject invention provide a lighting assembly for interior vehicular illumination which is both directionally and focus adjustable, and which is convenient to operate.

[0023] Referring to the figures, wherein like numerals indicate like or corresponding parts throughout the several views, a lighting assembly according to the subject invention is generally shown at 10 in FIG. 1 positioned within a headliner 12 under the roof of a motor vehicle. For reference, B and C pillars 14 are shown extending from the headliner 12. Although mounting the lighting assembly 10 within the headliner 12 is a preferred application of the invention, the lighting assembly 10 can be conveniently located in other portions of a motor vehicle, including within the trim features of the pillars 14, in a door panel, in a console or armrest, in the dashboard, in the trunk area, in the engine compartment, or in any other convenient location. The lighting assembly 10 is adjustable between flood and spot lighting conditions so that regardless of its location within the motor vehicle, it is useful for both general and task lighting. Furthermore, the lighting assembly 10 is fully directionally adjustable in both the flood and spot lighting conditions thus providing increased functionality and convenience.

[0024] Referring to FIGS. 2 and 3, the lighting assembly 10 is shown including a housing, generally indicated at 16 for attaching to a supporting member, such as the headliner 12. The housing 16 may take many shapes and forms, but is shown for illustrative purposes including a cylindrical sleeve 18 and a flange-like bezel 20 which lays against the visible side of the headliner 12 to cover the hole and support the lighting assembly 10 thereagainst. The sleeve 18 is provided with a cam lock feature 22 which cooperates with a support plate 24 located on the recessed side of the headliner 12. Thus, the headliner 12 is sandwiched between the support plate 24 and the bezel 20, with the cam lock 22 securing the assembly 10 in its operative position.

[0025] A light source, generally indicated at 26, is carried within the housing 16 and functions to project light along a light path which is represented by phantom lines 28 in FIGS. 5 and 6. The light source 26 can take any convenient form and embodiment, including an incandescent bulb, however in the preferred embodiment the light source 26 comprises one or more light emitting diodes (LED) 30. The LED 30 is mounted on a back plate 32 which may also contain a circuit board 34 through which electricity from a power input 36 is directed. The power input 36, which in the case of a motor vehicle application includes a DC power supply, is thus operatively connected to the light source 26, through the circuit board 34, for selectively energizing the light source 26.

[0026] The back plate 32 is joined to an inner gimbal, generally indicated at 38, which in turn is moveably supported within the housing 16. This is accomplished by pivotally connecting the inner gimbal 38 to a cross 40 via pintals 42 which lie across a common first axis A. The cross 40, in turn, is pivotally connected to the sleeve 18 of the housing 16 via perpendicular pintals 44 seated in corresponding holes 46 in the sleeve 18. The pintals 44 are aligned along a common second axis B. The first axis A and the second axis B are thus perpendicular to and intersect one another to provide free angular movement of the inner gimbal 38 relative to the housing 16. Thus, because the LED 30 and back plate 32 are fixed relative to the inner gimbal 38, they likewise enjoy a free range of orbital movement within the housing 16, thereby providing directional adjustment to the lighting assembly 10.

[0027] An optical member, generally indicated at 48, is positioned to influence the light path 28, and is moveable between a flood position and a spot position. In the flood position, light from the light source 26 is dispersed over a generally wide area within the passenger compartment, as shown in FIG. 5. By contrast, when the optical member 48 is in the spot position, light from the light source 26 is focused over a generally narrow area within the passenger compartment. The optical member 48 can take many forms. As an example, the optical member 48 could be a reflector to focus the light path 28 by varying its shape or its spatial relation to the light source 26. Preferably however, the optical member 48 is a lens 50 which is positioned within the light path 28 at all times. Alternatively, the optical member 48 may be a combination of reflector and lens 50, and can be of the type which moves into and out of the light path 28, in relative terms, as it moves between the flood and spot positions. Also, those skilled in the art will appreciate that the optical member 48 may remain stationary relative to the inner gimbal 38, or perhaps relative to the housing 16, while the light source 26 is moved. Regardless of the design strategy, the optical member 48 moves relative to the light source 26, and may remain in the light path 28 at all times, as shown in the accompanying figures, or may move intermittently into and out of the light path 28.

[0028] Referring now to FIGS. 5 and 6, the lens 50 is shown in its flood position in FIG. 5. The lens 50 is supported within a frame 52. The frame 52 is a cylindrical member sized for sliding relative movement within an opening 54 in the inner gimbal 38. A shoulder stop 56 extending from the frame 52 abuts the inside surface of the inner gimbal 38, behind the opening 54, for limiting travel of the frame 52. Thus, the fully extended position of the optical member 48 is shown in FIG. 6 and comprises the spot position wherein the shoulder stop 56 abuts the inner gimbal 38 and is effective for holding the lens 50 in the spot position.

[0029] In the flood condition, the lens 50 is spatially closer to the LED 30 than the when lens 50 is in the spot position. The frame 52 further includes at least one, and preferably four runners 58 which slidably engage corresponding linear tracks 60 provided in the inner gimbal 38. The runners 58 and their corresponding tracks 60 guide movement of the optical member 48 between its flood and spot positions. These runners 58 and tracks 60 hold the lens 50 in a proper orientation relative to the LED 30 so that the optical characteristics of the lens 50 perform according to design in both the flood and spot conditions. The runners 58 may be offset from one another in a non-symmetrical fashion so as to require assembly of the optical member 48 within the inner gimbal 38 in a particular orientation.

[0030] Although, in the preferred embodiment, the light source 26 comprises a single LED 30 which emits white light, it is possible to vary the color of the light path 28 by various means. For example, the lens 50 can be coated or doped with various elements to produce a particular color distribution, or a cluster of LEDs can be chosen from the red, green and blue varieties and grouped so as to emit a particular color or hue within the light path 28. Also, a different combination of colored LEDs 30 can be energized in the flood condition as opposed to the spot condition so that different hues or intensities of lighting can be emitted in the various conditions. Furthermore, it is possible to establish one or more intermediate positions of the optical member 48 relative to the light source 26 between the flood and spot positions so as to provide a graduated or infinitely variable focusing of the light path 28.

[0031] In the preferred embodiment, however, the light assembly 10 is provided with only two conditions, flood lighting and spot lighting as shown in FIGS. 5 and 6. This is accomplished by providing a pair of metallic leaf springs 62 on the back plate 32 which react against the runners 58 and urge the frame 52 toward the spot light position with the shoulder stop 56 abutting the inner gimbal 38. A bridge-like stabilizer 65 may extend between the two springs 62. When the optical member 48 is moved to the flood position of FIG. 5, the leaf springs 62 are compressed. A latch mechanism, generally indicated at 64, is operatively disposed between the frame 52 and the inner gimbal 38 for holding the lens 50 in its flood position. The latch mechanism 64 includes a flexible finger 66 which extends in cantilever fashion from the back plate 32. The finger 66 is disposed in a path 68 which is formed around a cam member 70 extending from one of the runners 58. (The path 68 is represented by phantom directional arrows in FIG. 7.) The finger 66 traces a course along the path 68 as the lens 50 moves between its flood and spot positions. Thus, as shown in FIG. 7, the finger 66 is positioned below the cam member 70 when the lens 50 is in its spot position. However, as the lens 50 is forced, against the urging of the leaf springs 62, toward its flood position, the finger 66 follows the path 68 around the left edge of the cam member 70. A pocket 72 is formed in the upper portion of the cam member 70 and functions to temporarily trap the finger 66 when the lens 50 has been moved to the fully compressed flood position. Thus trapped in the pocket 72, the finger 66 holds the lens 50 in the flood condition, thereby placing the latch mechanism 64 in tension. To return the optical member 48 in the spot position, a slight further compressive force is applied to the frame 52, allowing the resilient finger 66 to lift out of the pocket and continue along the path 68 about the right surface of the cam member 70. Thus, the optical member 48 returns to the spot condition under the urging of leaf springs 62. In much the same manner as a ball point pen is clicked between extended and retracted conditions, the optical member 48 is cycled between flood and spot positions by manual pressure applied repeatedly against the lens 50. This cycling between flood and spot positions is controlled in part by the finger 66 orbiting the path 68 about the cam member 70.

[0032] The lighting assembly 10 includes a switch 74 which is responsive to movement of the optical member 48 for automatically interrupting the operative connection between the power input 36 and the light source 26 when the optical member 48 is moved to its flood position. The switch 74 automatically restores the operative electrical connection when the optical member 48 is moved to the spot position (FIG. 6). Thus, the switch 74 energizes the light source 26 with a focused beam of light 28 directed into the passenger compartment whenever the optical member 48 is moved to its spot position.

[0033] The switch 74 may take any of a variety of forms. Preferably, the switch 74 is positioned on the back plate 32, and may be incorporated into the springs 62. In this configuration, the springs 62 are formed with hook-shaped free ends 63 which rest against a common contact surface 75 when in the spot position. The contact surface 75 is electrically connected to the power input 36. The other, fixed ends of the springs 62 are operatively joined to the circuit board 34 so that electricity is transmitted from the power input 36 to the circuit board 36 via the leaf springs 62 touching the contact surface 75. This condition is illustrated in FIG. 7. When the lens 50 is moved to the flood position, the free ends 63 of the springs 62 slide out of registry with the contact surface 75, toward the right as viewed from FIG. 7, thus opening the switch 74.

[0034] In FIGS. 8 and 9, the switch 74 is shown schematically within an overall circuit which includes a power source, such as the vehicle battery 76. The switch 74 is positioned between the battery 76 and the LED 30 so that, when closed, the LED is energized and emits light. Preferably, the circuit also includes a lighting control circuit, generally indicated at 78, which is responsive to an override signal for activating the light source 26 independently of the switch 74 when the optical member 48 is in the flood position. In the case of FIG. 8, the lighting control circuit 78 comprises a single door switch 80 which leads to an override power input 82 associated with the lighting assembly 10. Whereas the primary power input 36 receives operating power at all times (or could receive part time power via an ignition switch) so that the LED 30 is activated using this operating power via the switch 74. However, the override power input 82 receives a signal from the lighting control circuit 78 depending on the state of the door switch 80. When the door switch 80 is open, no signal is supplied to the override power input 82. When the door switch is closed, override power input 82 receives the signal in the form of operating power from the battery 76 which activates the LED 30 regardless of the position of the optical member 48.

[0035] Referring again to FIG. 7, a secondary contact surface 84 is shown adjacent the contact surface 75. The secondary contact surface 84 is electrically connected to the override power input 82. When the lens 50 is pushed to its flood position, the free ends 63 of leaf springs 62 slide into registry with the secondary contact surface 84. Thus whenever the lighting control circuit 78 calls for lighting, such as when a door is opened, the secondary contact surface 84 is energized. If the free ends 63 of leaf springs 62 happen to be touching the secondary contact surface 84, then the circuit board 34 will be energized and the LED 30 fired.

[0036] FIG. 9 shows a second example circuit which is a more typical embodiment in which the lighting control circuit 78′ is connected to several door switches 80′ and perhaps other inputs as well, such as an instrument panel switch (not shown). The functionality of the assembly 10 in this FIG. 9 is otherwise the same as that described above in connection with FIG. 8. More particularly, the lighting control circuit 78′ allows an override signal, such as from the door switch 80, 80′ or an instrument panel switch or other signal to energize the light source 26 even when the lens 50 is in its flood condition.

[0037] In practice, this arrangement allows the lighting assembly 10 to function as a dome, or general lighting feature whenever its in the retracted, flood condition so that it is energized as the doors are opened, or otherwise when the general interior illumination systems are activated. When task lighting is demanded and the lighting control circuit 78, 78′ is otherwise inactive, the lighting assembly 10 can be used in its focused task lighting mode by simply moving the optical member 48 to its spot position. Thus, by simple pressure of an operator's finger against the lens 50, the lighting assembly 10 can be placed in its spot position and simultaneously activated to shine a focused path of light 28 within the passenger compartment. By reversing this single operation, the lighting assembly can be turned off and returned to its general flood illumination condition. The gimbaled fixation of the light source 26 within the housing 16 allows directional adjustment of the light path 28 both in the spot light condition and also in the flood light condition. Thus, the lighting assembly 10 is functionally simple to use, even by a vehicle driver without undue distraction or complicated multiple inputs required. Additionally, the lighting assembly 10 is highly functional by allowing reorientation of the light path 28 in both the flood and spot conditions to better accommodate occupants and various conditions.

[0038] While the invention has been described with reference to an exemplary embodiment, it will be understood by those skilled in the art that various changes may be made and equivalents may be substituted for elements thereof without departing from the scope of this invention. Obviously, many modifications and variations of the present invention are possible in light of the above teachings. It is, therefore, to be understood that within the scope of the appended claims, the invention may be practiced otherwise than as specifically described.