LIGHTING DEVICE

Description

TECHNICAL FIELD

[0001] The invention relates to a lighting device.

[0002] The invention applies in particular to the field of interior lighting of an enclosed space such as the passenger compartment of a motor vehicle, and more particularly to ambient lighting devices, ceiling lights and reading lights. STATE OF THE ART

[0003] A vehicle interior lighting device, of the ceiling light or reading light type, comprising one or more light sources, including LEDs supported by an electronic board (printed circuit board or PCB), is known, in particular from document FR3026692; these sources being covered by an optical device for diffusing the light generated by the light source(s).

[0004] The lighting is controlled via a touch interface with a transparent contact or touch surface to allow the light generated by the LEDs to pass through.

[0005] The touch interface is either capacitive or resistive, translating the user's finger touch on the surface into a signal that controls the lighting. The operation of a touch interface, well understood by those skilled in the art, will not be described in detail here.

[0006] All the components are mounted in a housing whose lid is fitted with aesthetic elements (glass, mask, etc.). In this arrangement, the touchscreen interface is mounted on the housing by means of a system of slides and corresponding ribs. From the perspective of the mounting operation itself (centering, locking in position, etc.) and the reduction of play, this is not an optimal solution. Document GB 2425590 A shows a lighting device according to the preamble of claim 1. DESCRIPTION OF THE INVENTION

[0007] The invention aims to facilitate the assembly of the device and to strengthen its resistance to vibrations and consequently guarantee electrical contact between the light sources and the touch interface for controlling the lighting.

[0008] The device according to the invention uses a mechanical clip-on assembly which allows for simple and "blind" assembly.

[0009] Such an assembly usually requires on-the-piece development to find the right compromise between the durability of the parts in use and the clipping force.

[0010] Indeed, despite all the care taken with this type of assembly, noise problems due to vibration of one of the parts and squeaking due to movement of one part relative to the other, for example when rolling, can appear and impair the quality perceived by the user.

[0011] And as a side effect, the electrical contact between the touch surface and the card may no longer be guaranteed.

[0012] The tolerance ranges of each part do not allow for a "zero" clearance assembly. The assembly is therefore either mounted under stress, with the risk of breaking or desoldering the electrically conductive mechanical parts, or with some clearance, with the risk of noise induced by this clearance.

[0013] To overcome these drawbacks, the present invention relates to a lighting device comprising a housing containing at least one light source, said housing having a wall at least partially transparent supporting a touch interface for controlling the light source and allowing the light generated by the light source to pass through, and a cover closing the housing; the assembly formed by the housing and the cover being assembled without play by clipping means, said lighting device further comprising a flexible compressed mechanical and electrical linking means between the touch interface and the light source allowing both to control the light source and to compensate for the stresses exerted by the clipping means.

[0014] According to the invention, the housing has a bowl shape, the bottom wall of which supports the touch interface and the opening of which is closed by a printed circuit board supporting the light source; the light source being oriented towards the bottom wall (6).

[0015] According to the invention, the touch interface comprises a conductive surface conforming to the bottom wall, having at least one conductive part extending from the conductive surface to the printed circuit board; the free end of said conductive part defining an electrical contact participating in the transmission of a lighting control signal to the printed circuit board to control the lighting of the light source.

[0016] According to another characteristic, the mechanical and electrical linking means is arranged between the electrical contact and the printed circuit board.

[0017] According to another characteristic, the mechanical and electrical linking means is a hollow tubular sleeve, made of elastomer, loaded with conductive pigments whose density is determined to ensure electrical continuity between the electrical contact and the printed circuit board.

[0018] According to another feature, the cover has a stop exerting a bearing force on the printed circuit board; said stop being centered on the tubular sleeve.

[0019] According to another feature, an optical device is disposed between the back wall and the printed circuit board opposite the light source, to guide the light to the back wall; said optical device having a light inlet face opposite the light source and a light outlet face opposite the back wall.

[0020] According to another feature, the optical device includes at least one centering pin cooperating with the printed circuit board to center the light-input face of the optical device on the light source.

[0021] The present invention also relates to a motor vehicle comprising at least one lighting device as described above, located inside the passenger compartment of the motor vehicle.

[0022] Depending on one characteristic, the lighting device is a reading light or a ceiling light. PRESENTATION OF THE FIGURES

[0023] Other features and advantages of the present invention will become apparent from the following unlimited description, with reference to the drawing of the single figure which represents a cross-sectional and perspective view of an example embodiment of a lighting device according to the invention. DETAILED DESCRIPTION

[0024] In the following description, "interior" or "internal" will refer to all elements or surfaces located inside the lighting device according to the invention, and, in contrast, "exterior" or "external" will refer to all elements or surfaces located outside the lighting device according to the invention.

[0025] Similarly, the terms "upper" and "lower" are considered in reference to the orientation of the lighting device as illustrated in the figure 1 .

[0026] An embodiment of a lighting device 1 according to the invention, which may be a reading lamp or a ceiling light, is shown with reference to the single figure ( FIG. 1 ) following a perspective cut highlighting the different elements of the lighting system 1.

[0027] This lighting device 1 comprises a housing 2 closed by a cover 3. It is noted here that the designation of housing and cover is a simple convention and can be reversed: the housing becoming the cover and vice versa.

[0028] The assembly formed by the housing 1 and the cover 2 is assembled by clipping. Only one of the four clipping means 4 is visible in the embodiment of the figure 1 The four clipping means 4 are provided respectively at the four corners of the housing 2 which has a general shape of a rectangular parallelepiped.

[0029] The clipping means 4 comprise, in a known manner, elastically deformable tabs (or clips), made of material with the housing 2 which respectively terminate in stops having guide ramps and which cooperate respectively with antagonistic stops defined by the edges of openings made at the four corners of the cover 3. The cover 3, just like the housing 2, has a general shape of a rectangular parallelepiped.

[0030] With such clipping means, once the assembly is complete, there is no more play between the housing 2 and the cover 3.

[0031] The housing 2 has a general bowl-like shape 5 with an opening 51 and a back wall 6 which, in this embodiment, is flat and at least partially transparent to allow light from the lighting source described below to pass through, while concealing the interior of the housing from a user inside the vehicle. The back wall 6 also defines a touch surface 7 for a touch interface for controlling the lighting.

[0032] Only the bottom wall 6 of the housing 2 is visible and accessible by the vehicle's passengers for lighting control, when it is mounted in the passenger compartment.

[0033] The housing 2 also has a peripheral support ledge 8 which receives a corresponding support ledge 9 from the cover 3. The two ledges 8 and 9 are held pressed together by the clipping means 4.

[0034] The casing 2 and its lid 3 are obtained in a known manner, by injection of plastic material.

[0035] The partially transparent bottom wall 6 is obtained by bi-material injection, for example of PC (Polycarbonate) and ABS (acrylonitrile butadiene styrene).

[0036] The various elements contained in the housing 2 (internal elements) are now described according to their order of assembly in the housing 2 by describing their shape, their function and their interface with the other elements or with the housing 2 and the cover 3.

[0037] The housing 2 accommodates, on the inner face of the back panel 6, a conductive metal plate 9, also referred to as the "antenna," which, together with the touch surface 7, defines the touch interface of the lighting device 1 and thus controls the lighting. The outer contour of the conductive plate 9 follows the inner contour of the inner face of the back panel 6. The outer contours are generally rectangular in shape.

[0038] The antenna 9 has four tabs 92 extending in pairs from the ends and from the lateral edges of the plate. The tabs 92 are bent at approximately 85° to the main plane of the metal plate. Only one tab 92 is shown in the figure. The housing 2 has EPDM (ethylene-propylene-diene monomer) ribs 93 against which the tabs 92 bear under pressure during assembly. The EPDM also eliminates any risk of creaking after assembly. Two parallel ribs 93 are formed in the housing 2, opposite each of the tabs 92. They are integral with the housing 2. Only two ribs 93 are shown in the figure.

[0039] The conductive plate 9 is perforated in its central part to allow the passage of an optical device 10, which is housed in the central area of ​​the inner face of the bottom wall 6 of the housing 2. The inner face has a raised section 11 in this area. The raised section 11 is obtained by a local thickening of the bottom wall 6. The raised section 11 also serves as a centering stop for the conductive plate 9. In an alternative embodiment, the raised section 11 is obtained from the thickness of an added piece bonded or welded to the bottom 6 of the housing 2. This added piece 11, also referred to as the "lens," must be transparent to allow light to pass through while obscuring the interior of the housing 2 from a user inside the vehicle.

[0040] The optical device 10 is shaped to define a light guide made, for example, from a crystal PC type material, for the light generated by a lighting source 14 of the lighting device 1. The exit face of the light guide 10 is centered on the central area of ​​the inner face of the bottom wall 6. The light entrance face of the light guide 10, which is parallel to the plane of the opening 51 of the housing 2, is shaped to concentrate the beam of light generated by the lighting source 14 while limiting light leakage into the housing 2.The light guide 10, generally elliptical in shape, then directs the beam towards its exit face which flares out to the interface with the central area of ​​the bottom wall 6 which is transparent to the beam, to diffuse the lighting outwards from the housing 2, i.e. into the passenger compartment when the housing 2 is mounted in the passenger compartment, for example in the headliner, window pillar, center pillar, .

[0041] The housing 2 then accommodates a printed circuit board (PCB) 12 which rests on the upper face 13 of the housing 2 by closing the opening 52. The PCB 12 is centered on the upper face 13 of the housing 2 by four centering pins arranged respectively at the four corners of the upper face 13 of the housing 2. (The centering pins are not visible in the figure).

[0042] PCB 12 supports the lighting source 14, typically one or more LEDs.

[0043] To optimize the alignment of the light beam generated by the light source 14 with respect to the optical axis of the light guide 10, and therefore with respect to the PCB 12 supporting the light source 14, four centering pins 15 are arranged around the light-entry face of the light guide 10. Only one centering pin 15 is visible in the figure. These pins are formed from the material of the light guide 10 and are press-fitted into through holes machined in the thickness of the PCB 12.

[0044] The conductive plate 9 further includes a conductive part defining a conductive metallic tab 90, formed from the material with the plate 9, and which is shaped to extend out of the plane of the plate 9 in a general direction substantially perpendicular to the plane of the plate 9. The end of the tab 90 defines an electrical contact 91 of an electrical connection between the conductive plate 9 and the PCB 12.

[0045] Advantageously, the contact 91 is not directly connected mechanically and electrically (by welding, gluing, ...) to the PCB 12, but the mechanical and electrical connection is made by means of a flexible and electrically conductive sleeve 20 which is interposed between the contact 91 and a conductive receiving area 21 of the PCB 12.

[0046] Sleeve 20 is made for example from a polymer loaded with conductive powder or conductive pigments and can alternatively be made from any type of adaptable flexible material: a natural or synthetic rubber, a thermoplastic elastomer, silicone, a flexible polymer such as viscoelastic polyurethane foam or a cellulosic polymer, or equivalents.

[0047] The sleeve 20 is advantageously carried and centered on a centering pin 22 onto which it is threaded along almost its entire length.

[0048] The centering pin 22 is made of material with the bottom wall 6 or, in the variant described above, with the piece added to the bottom wall 6. It extends perpendicularly to the inner face of the bottom wall 6.

[0049] It has a general cylindrical shape, gradually widening towards its base. The base of the centering pin 22 is enlarged to define a flat, horizontal surface 23 for the electrical contact 91.

[0050] The sleeve 20 advantageously has the shape of a hollow tube with a generally cylindrical shape and a circular cross-section, and which, by elastic deformation around the centering pin 22, when it is threaded onto the centering pin 22, is held firmly around the centering pin 22 and rests by its base on the receiving surface 23. The flared base of the sleeve 20 is mechanically secured to the electrical contact 91. The length of the sleeve 20 is chosen to be greater than the length (height) of the centering pin 22 considered from the receiving surface 23 of the centering pin 22 to its free end.

[0051] The cover 3 has on its inner face a stop 24 made of material with the cover 3 and which applies pressure to the opposite face of the PCB supporting the light source 14. The stop 24 is located in the axis of the sleeve 20.

[0052] The cover 3 is attached to the housing 2 and assembled to the housing 2 by snapping it into place via the clipping means 4, and the internal elements are thus sandwiched between the housing 2 and the cover 3.

[0053] In this embodiment, all the internal elements are mounted inside the housing 2 and it is the cover 3, attached to the housing 2, which ensures the stressing of the internal elements of the housing 2.

[0054] The assembly thus produced must be able to meet the compromise between maintaining the internal elements without play and the clipping force.

[0055] The flexible sleeve 20 ensures, through its compression at the time of assembly of the cover 3 with the housing 2, the clipping counter-reaction.

[0056] It is the difference in length J between the sleeve 20 and the centering pin 22 (the length of the pin 20 is considered from the interface of the contact 91 with the base of the pin 20) which allows the sleeve 20 to deform by compression along its main axis of deformation and to absorb all the clearances of the assembly due to the tolerance intervals of the elements and their wear, to arrive at a zero clearance assembly.

[0057] Furthermore, and advantageously, the sleeve 20 provides a flexible electrical connection between the contact 91 and the light source supported by the PCB. A conductive track, not shown, connects the mounting surface 21 of the PCB to the light source, i.e., to the connection pins of the LED(s) 14.

[0058] By compressing it along its main axis of deformation, the pigments of the conductive powder in sleeve 20 are brought into contact and ensure electrical continuity along the entire length of sleeve 20.

[0059] Thus, with the use of a single piece, the conductive flexible sleeve 20, according to the present invention, makes it possible to meet the dual constraint of ensuring a zero-play assembly and a reliable electrical contact between the touch interface for controlling the lighting, via the touch surface 7, and the light source 14.

[0060] A male connector 25 for electrically connecting the lighting device 1 to an electrical supply harness for the passenger compartment, not shown, is formed by contact pins 26 which are soldered to one end of the PCB 12. The housing of the connector 25, surrounding the contact pins 26, is made of the same material as the housing 2.

Claims

1. Lighting device (1) comprising a housing (2) housing at least one light source (14), said housing (2) comprising an at least partially transparent bottom wall (6) supporting a tactile interface (7) for controlling the light source (14) and allowing the light generated by the light source (14) to pass through, and a cover (3) closing the housing (2); the assembly formed by the case (2) and the cover (3) being assembled without play by clipping means (4),the case (2) having a bowl shape (5) whose bottom wall (6) supports the tactile interface (7) and whose opening (51) is closed by a printed circuit board (12) supporting the light source (14);the light source being oriented towards the bottom wall (6); said lighting device being characterized in that it (1) further comprises a flexible mechanical and electrical connection means (20) compressed between the tactile interface (7) and the light source (14) allowing both to control the light source (14) and to compensate for the stresses exerted by the clipping means (14); the touch interface having a conductive surface (9) conforming to the bottom wall (6), including at least one conductive portion (90) extending from the conductive surface (9) toward the printed circuit board (12); the free end of said conductive portion (90) defining an electrical contact (91) participating in the transmission of a light control signal to the printed circuit board (12) to control the illumination of the light source (14).

2. The lighting device (1) according to the preceding claim, wherein the mechanical and electrical connecting means (20) is disposed between the electrical contact (91) and the printed circuit board (12).

3. Lighting device (1) according to the preceding claim in which the mechanical and electrical connection means (20) is a hollow tubular sleeve, made of elastomer, charged with conductive pigments whose density is determined to ensure electrical continuity between the electrical contact (91) and the printed circuit board (12).

4. Lighting device according to the preceding claim in which the cover (3) comprises a stop (24) exerting a bearing force on the printed circuit board (12); said stop (24) being centered on the tubular sleeve (20).

5. The lighting device (1) according to any one of claims 1 to 4, wherein an optical device (10) is arranged between the bottom wall (6) and the printed circuit board (12) facing the light source (14), for guiding light to the bottom wall (6); said optical device (10) comprising a light input face facing the light source (14) and a light output face facing the bottom wall (6).

6. The lighting device (1) according to the preceding claim, wherein the optical device (10) comprises at least one centering pin (15) cooperating with the printed circuit board (12) to center the light input face of the optical device (10) on the light source (14).

7. Motor vehicle comprising at least one lighting device (1) according to one of the preceding claims, arranged inside the passenger compartment of the motor vehicle.

8. Motor vehicle according to the preceding claim in which the lighting device (1) is a reading light or a ceiling light.