WO2008129321A1

WO2008129321A1 - Light assembly

Info

Publication number: WO2008129321A1
Application number: PCT/GB2008/050274
Authority: WO
Inventors: Richard Gray
Original assignee: Britax (Pmg) Limited
Priority date: 2007-04-20
Filing date: 2008-04-18
Publication date: 2008-10-30
Also published as: GB0707631D0

Abstract

An interior vehicle light assembly comprises a base section (10) which is secured to a suitable surface in a vehicle cabin and is provided with an electrical supply to electrical leads (12). An LED printed circuit board (PCB) (14) is secured to and fitted on top of a power PCB (16). A lens (18) is secured onto the base section (10) by means of an ultrasonic welding technique. The resulting unit is waterproof, dustproof and has no moving parts. The lighting unit is switched by means of a single channel touch sensor integrated circuit.

Description

Light Assembly

This invention relates to a vehicle light assembly, particularly, but not limited to, an interior vehicle light assembly.

Existing interior vehicle light assemblies typically consist of a base section that this secured to an interior part of a vehicle cabin, with an incandescent or LED lamp fitted to that base and provided with a suitable power supply. A lens is secured to the base to cover lamp. The lighting assembly is switched by means of the lens being a rocking assembly. The switch is operated by moving the rocking lens assembly from one side to another in order to switch the light between its on to off and off to on positions .

Disadvantages arise with this prior art type of assembly, because it has moving parts which are prone to failure and so reduce the serviceable life of the light assembly.

An alternative configuration of existing interior light assembly is to have a push switch with a similar construction to that mentioned above. Similar disadvantages are associated with the use of a push switch, as they are with a rocker switch.

It is an object of the present invention to address the above mentioned disadvantages.

According to a first aspect of the present invention there is provided a light assembly adapted to be mounted on a surface for use, the light assembly including at least one light emitting element located behind a cover portion, wherein the light assembly is adapted to be switched between active and inactive states by a user touching or being in close proximity to the cover portion.

The light assembly is preferably an internal vehicle light assembly .

Preferably, the cover portion is a translucent cover. The cover portion may be a lens.

The light assembly preferably includes control means, which preferably include a touch/proximity sensor, a detector portion of which may be located on an upper face of the control means, preferably beneath the cover portion. The detector portion may be an aerial. The detector portion preferably forms a loop. The detector portion is preferably formed on a PCB, preferably as an etched element of the PCB.

The control means are preferably programmable. The control means are preferably programmable to set a delay time for turning on or off the at least one light emitting element, for example in response to a vehicle door opening and/or closing.

The cover portion preferably incorporates a capacitive coupler. The capacitive coupler preferably extends from a surface of the cover towards the control means, preferably towards the detector portion. The capacitive coupler preferably contacts the detector portion, to give improved capacitive coupling. An end of the capacitive coupler preferably has substantially the same shape as the detector portion. The capacitive coupler may be tubular with a cross-section corresponding to the shape of the detector portion. The detector portion may be continuous. The capacitive coupler may extend towards the control means from a position spaced from a periphery of the cover portion .

According to another aspect of the present invention there is provided a method of manufacturing an internal vehicle light assembly, the method comprising: programming a programmable portion to illuminate a light emitting element of the light assembly for a predetermined period; and assembling the programmable portion, at least one light emitting element, and a touch/proximity sensor behind a cover portion.

The programming is preferably based on input from a vehicle door, to provide for example for illumination of the light assembly for a predetermined period after the door has been closed.

The invention extends to a method of controlling an internal vehicle light assembly using a programmable integrated circuit (PIC) , wherein signals from doors of a vehicle are used to determine the state of the light assembly .

The method includes the state of the light assembly being overridable by a user touching or being in close proximity to a cover of the light assembly. All of the features described herein may be combined with any of the above aspects in any combination.

For a better understanding of the invention, and to show how embodiments of the same may be carried into effect, reference will now be made, by way of example, to the accompanying diagrammatic drawings in which:

Figures Ia and Ib are schematic perspective views from above and below respectively of an LED printed circuit board (PCB) assembly;

Figure Ic is a schematic view from above of the LED PCB assembly;

Figures 2a and 2b are schematic perspective views from above and below respectively of a power PCB assembly for attachment to the LED PCB assembly shown in Figures Ia to

Ic;

Figure 3 is a schematic side view of the power PCB assembly shown in Figures 2a and 2b;

Figure 4 is a schematic circuit diagram for the connections and components on the power PCB assembly;

Figure 5 is a table showing data concerning the components shown in Figure 4;

Figure 6 is a schematic perspective view of the PCBs of the earlier figures fixed into a base section; Figure 7a is a schematic view from above of a lens section for attachment to the base section; and

Figure 7b is a schematic view from below of the lens section.

It has been realised that great advantages would be possible if a sealed unit interior light assembly for use in a vehicle could be provided. Such a sealed unit would be sealed for life and non-serviceable. In order to achieve this and also to achieve a minimum service life of at least 10,000 hours, LED lamps have been used as described below (At least 5,000 hours is also a possible minimum requirement) . However, the moving parts of prior art devices do not lend themselves to being sealed for life units which are non-serviceable.

In view of the above, an interior vehicle light assembly as shown in the accompanying figures has been produced. The unit comprises a base section 10 (see figure 6) which is secured to a suitable surface in a vehicle cabin and is provided with an electrical supply to electrical leads 12. An LED printed circuit board (PCB) 14 is secured to and fitted on top of a power PCB 16, described below in more detail. A lens 18 is secured onto the base section 10 by means of an ultrasonic welding technique. The resulting unit is waterproof, dustproof and has no moving parts .

The lighting unit is switched by means of a single channel touch sensor integrated circuit, such as that supplied by the Quantum Research Group with reference number QTlOO. The QTlOO charge transfer touch centre is a self-contained digital integrated circuit capable of detecting near proximity or touch. It can operate through any dielectric like glass, plastic, stone, ceramic and even most kinds of wood. It can also turn small metal bearing objects into intrinsic sensors making them responsive to proximity or touch .

The touch sensor integrated circuit includes an aerial 20 which is located on the LED PCB 14. In the example shown, the aerial is arranged in a circular loop, but other shapes of aerial would also be possible.

The aerial 20 connects to the main body of the touch sensor, which is located on the power PCB 16 below.

Within the loop of the aerial 20 are located two LEDs 22a and 22b which face upwards to allow light to pass through the lens 18. The LEDs used are, for example, K2 LEDs, which are capable of taking a current 5OmA to 1.5 Amps. As can be seen from Figure Ib, a connector block 24 is located on the underside of the PCB LED 14, which allows for connection of the LED PCB 14 to a corresponding connector 26 on the upper side of the power PCB 16, as shown in Figure 2a.

The power PCB 16 is populated with the components shown in Figure 4 and described in more detail in Figure 5.

One of the design considerations for the light assembly described is to allow switching of the LEDs 22a and 22b by a user with either a bare hand or a gloved hand. The design considerations include the fact that the touch sensor circuit must be sufficiently sensitive to work in either of those circumstances, but must not be activated if a user simply brushes passed the lens 18 of the light assembly. The correct sensitivity is arrived at by selection of the correct value for capacitor C6 in Figure 4 to balance between a lack of sensitivity and over sensitivity .

A programmable integrated circuit (PIC) on the power PCB 16, designated by U3 on the circuit diagram of Figure 4 is programmed to operate the LEDs in two main circumstances. The first is when the light is switched on or off by a user touching the lens 18. Secondly, the usual timing functions for a delay switch on or switch off for an interior light in a vehicle are also programmed into the PIC, U3.

A significant advantage of the light assembly device described is that the programming of the PIC can be amended to suit a different user's needs, for example the delay time on the light switch, controlled by a vehicle door opening or closing can be programmed to a suitable time, for example fifteen seconds, or a time specified by the user. Previously, it would have been necessary to amend the electronic components within the light assembly to achieve a different delay time. Thus, significant manufacturing cost reductions have been achieved by programming of the delay times etc. Furthermore, the use of software to control the features of an interior lamp is a particularly beneficial feature of the light assembly described.

The lens 18 fits over the base 10, as described above. The lens has an internal projecting rim 28, which projects from an inside face 30 of the lens 18 towards the aerial 20 of the touch sensor integrated circuit. The projecting rim 28 provides capacitive coupling between a front face 32 of the lens which is touched 18 by a user and the aerial 20 of the touch sensor IC. The coupling is important to ensure that the switching of the LEDs 22a and 22b is achieved. The capacitive coupling is also necessary because of the sealed nature of the unit and the necessity of having a robust lens with sufficient strength to avoid damage within a vehicle by being knocked or the like.

The projecting rim 28 projects downwards onto and makes contact with the aerial 20 so that there is good capacitive coupling.

An important feature of the lighting unit disclosed is the capacitive coupling, because it combines a tough, sealed unit with a touch sensitivity.

Existing touch sensitive domestic lights do not have the same capacitive coupling limitations, because the devices are considerably less robust. Consequently, the combination of the lens with the projecting rim 28 to provide capacitive coupling with the aerial is a significant advantage in this device.

The shape of the aerial 20 is circular in the example shown, but could be square or another shape.

In use, a user simply touches with a bare or gloved hand the lens 18, which changes the capacitance of the touch sensor integrated circuit by means of capacitive coupling between the user's hand, the protruding rim 28 and the aerial 20. The changing capacitance causes a threshold to be crossed which results in a triggering of the LED switching to either illuminate or extinguish the LED's 22a/b. In this description a reference to touching the lens 18 also encompasses a user nearly touching the lens.

Other relevant design options include the possibility that just one LED 22a could be used. Alternatively, more than two LEDs could be used. The shape of the projecting rim 28 is simply chosen to match the shape of the aerial, so a different aerial shape could result in a different shape of projecting ring 20.

Attention is directed to all papers and documents which are filed concurrently with or previous to this specification in connection with this application and which are open to public inspection with this specification, and the contents of all such papers and documents are incorporated herein by reference.

All of the features disclosed in this specification (including any accompanying claims, abstract and drawings), and/or all of the steps of any method or process so disclosed, may be combined in any combination, except combinations where at least some of such features and/or steps are mutually exclusive.

Each feature disclosed in this specification (including any accompanying claims, abstract and drawings) may be replaced by alternative features serving the same, equivalent or similar purpose, unless expressly stated otherwise. Thus, unless expressly stated otherwise, each feature disclosed is one example only of a generic series of equivalent or similar features.

The invention is not restricted to the details of the foregoing embodiment (s) . The invention extends to any novel one, or any novel combination, of the features disclosed in this specification (including any accompanying claims, abstract and drawings), or to any novel one, or any novel combination, of the steps of any method or process so disclosed.

Claims

1. A light assembly adapted to be mounted on a surface for use, the light assembly including at least one light emitting element located behind a cover portion, wherein the light assembly is adapted to be switched between active and inactive states by a user touching or being in close proximity to the cover portion.

2. The light assembly of claim 1, which is an internal vehicle light assembly.

3. The light assembly of claim 1 or claim 2, in which the cover portion is a translucent cover.

4. The light assembly of any preceding claim, in which the cover portion is a lens.

5. The light assembly of any preceding claim, which includes control means, including a touch/proximity sensor, a detector portion of which is located on an upper face of the control means

6. The light assembly of claim 5, in which the detector portion is an aerial.

7. The light assembly of claim 5 or claim 6, in which the control means are programmable.

8. The light assembly of claim 7, in which the control means are programmable to set a delay time for turning on or off the at least one light emitting element.

9. The light assembly of any preceding claim, in which the cover portion incorporates a capacitive coupler.

10. The light assembly of claim 9, in which the capacitive coupler extends from a surface of the cover towards the control means.

11. The light assembly of claim 9 or claim 10, in which the capacitive coupler is tubular with a cross-section corresponding to the shape of the detector portion.

12. A method of manufacturing an internal vehicle light assembly, the method comprising: programming a programmable portion to illuminate a light emitting element of the light assembly for a predetermined period; and assembling the programmable portion, at least one light emitting element, and a touch/proximity sensor behind a cover portion.

13. The method of claim 12, in which the programming is based on input from a vehicle door.

14. A method of controlling an internal vehicle light assembly using a programmable integrated circuit (PIC) , wherein signals from doors of a vehicle are used to determine the state of the light assembly.

15. The method of claim 14, which includes the state of the light assembly being overridable by a user touching or being in close proximity to a cover of the light assembly.