GB2339276A

GB2339276A - Self-illuminating pivotal switch

Info

Publication number: GB2339276A
Application number: GB9814603A
Authority: GB
Inventors: Frauk Stoll; Frauk Pohlau
Original assignee: Motorola Ltd
Current assignee: Motorola Solutions UK Ltd
Priority date: 1998-07-07
Filing date: 1998-07-07
Publication date: 2000-01-19
Also published as: GB9814603D0

Description

2339276 AN ELECMOMC USER OPERATM MUCH ARRANGEAIENT

Field of the Invention

This invention relates to electronic user operated switches, and particularly but not exclusively to switches for use in Automotive applications.

Background of the Inventio

Typically user operated switches require a separate illumination arrangement so that the user can easily locate them in the dark. This adds complexity and cost to the switch.

A known arrangement solves this problem by incorporating the illumination and switching functions together using a light emitting diode (LED) which serves to both illuminate the switch and to provide a light source which is selectively detected by a light detector in dependence upon the position of a switching member.

A problem with this arrangement is that the arrangement requires high manufacturing tolerances due to the optical characteristics of the switch.

Moulded Interconnect Device (MID) technology is concerned with the combination of electrical and mechanical features into a single electronic module, thereby reducing the number of parts and connections required.

An MID switch may be used for a complex arrangement such as an electronic module designed to operate an electric window motor. This requires a twoway switch arrangement for opening and closing the window, which ideally is integrated with logic circuitry within the module.

However, a complex switch cannot be easily incorporated with the combined illumination and switching function switch described above.

This invention seeks to provide an electronic user operated switch arrangement which mitigates the above mentioned disadvantages.

Summary of the Invention

According to the present invention there is provided an electronic user operated switch arrangement comprising: a switch housing; a switch member pivotally mounted in the switch housing and arranged to have a nonactuating position, at least one actuating position and at least one optical path; at least one light detecting arrangement mounted in the housing for detecting light along the at least one optical path and arranged to provide at least one actuating signal in dependence thereon; and illumination means for providing light to illuminate the switch arrangement, wherein the at least one optical path is arranged such that when the switch is in the at least one actuating position, light from the illumination means is incident upon the at least one light detecting arrangement, such that the at least one actuating signal is provided in dependence upon the position of the switch.

The switch arrangement preferably further comprises a spring element arranged to provide a spring force to urge the switch towards the nonactuating position. Preferably the spring element is integral with the switch housing.

The switch is preferably a rocker switch having first and second opposing portions, the rocker switch being arranged to be actuated by applying pressure to at least one of the opposing portions of the switch. Preferably the at least one optical path comprise first and second optical paths which are provided in the first and second opposing portions of the rocker switch respectively.

Alternatively the switch is a push-pull switch, arranged to be actuated by raising or lowering a lever end portion of the switch. Preferably the switch housing incorporates an integral printed circuit board having tracks to which the illumination means and the at least one light detecting arrangement are connected.

Preferably the switch arrangement further comprises a microcontroller arranged to control the functions of the switch arrangement. The illumination means is preferably a light emitting diode.

Preferably the switch arrangement is incorporated in a switching module.

In this way a switch arrangement is provided which can be easily integrated, and which combines actuation and illumination functions using a minimum number of components. 10 Bri-ef Description of thp, Drawings

An exemplary embodiment of the invention will now be described with 15 reference to the drawing in which:

FIG. 1 shows a top view of a preferred embodiment of an electronic user operated switch arrangement in accordance with the invention; FIG. 2 shows a sectional side view of the preferred embodiment of FIG. 1, with the switch arrangement in a first configuration; FIG. 3 shows a bottom view of the preferred embodiment of FIG. 1; FIG. 4 shows a sectional side view of FIG. 3, along the line AA, with the switch arrangement in a second configuration; FIG. 5 shows a sectional end view of the preferred embodiment of FIG. 1; FIG. 6 shows an alternative embodiment of an electronic user operated switch arrangement in accordance with the invention; FIG. 7 shows a top view of the arrangement of FIG. 6; and FIG. 8 shows an end view of the arrangement of FIG. 6, along the line DD.

Detailed Description of a Preferred Embodiment

Referring to FIG.s 1, 2 and 3 there is shown an electronic user operated switch arrangement 10, formed in part of an MID switch module, having a microcontroller and other circuitry (not shown). The arrangement 10 includes a PCB or circuit carrier 20, a rocker switch 30, light emitting diode (LED) 40, first and second light detectors 50 and 60, and a spring element 70.

One side of the PCB 20 (the side visible in FIG. 1) also forms part of the outer housing of the MID module, and the other side has tracks 80 which provide electrical connections to the LED 40 and the first and second light detectors 50 and 60.

The LED 40 receives power from the tracks 80 of the PCB 20 and is arranged to provide light to illuminate the top of the rocker switch 30 via a semitransparent portion of the rocker switch 30 (not shown). First and second light detectors 50 and 60 also receive power from the tracks 80 of the PCB 20 and are also coupled to provide signals on signal lines (tracks 80), when they detect incident light received from LED 40, in a manner to be further described below.

The rocker switch 30 is pivotally mounted such that it is free to rotate clockwise and anti-clockwise about an axis of rotation 32. The spring element 70, serves to provide a spring force which in the absence of other forces, causes the rocker switch 30 to be held at the centre of its rotation, a shown in FIG. 2. The spring element may be integrally formed in the rocker switch 30.

A first optical path 55, is formed in the rocker switch 30, and extends horizontally from the LED 40 towards the first light detector 50. Similarly a second optical path 65, is formed in the rocker switch 30, and extends horizontally -from the LED 40 towards the second light detector 60.

The first light detector 50 has a light aperture 52, through which incident light is detected. The second light detector 60 has a similar aperture (not shown). When the rocker switch 30 is held at the centre of its rotation, as shown in FIG. 2, the first and the second optical paths 55 and 65 do not convey light from the LED 40 to the light apertures (52) of either the first or the second light detectors 50 and 60 respectively.

In operation, and referring now also to FIG. 4, the switch arrangement 10 has three states defined by the position of the rocker switch 30. When no other forces are present other than the spring force provided by the spring element 70, the rocker switch is held at the centre of its rotation, as described above.

When a force is applied (by a finger, for example) to the left side of the rocker switch 30, (when viewed from above as shown in FIG. 1) it rotates to the position shown in FIG. 4. In this position, the first optical path 55 now conveys light from the LED 40 to the light aperture 52 of the first light detector 50, which in turn provides a first actuation signal via the tracks 80. When the applied force is removed, the rocker switch 30 returns to the centre position (shown in FIG. 2), and the light detector 50 ceases to provide the signal.

Similarly, when a force is applied to the right side of the rocker switch 30, it rotates to a position which is the reverse of that shown in FIG. 4. In this position, the second optical path 65 now conveys light from the LED 40 to the light aperture of the second light detector 60, which in turn provides a second actuation signal via the tracks 80. VVhen the applied force is removed, the rocker switch 30 returns to the centre position (shown in FIG. 2), and the light detector 60 ceases to provide the signal.

In this way three states are defined. In a first (off) state, no actuation signal is received from either of the first and second light detectors 50 and 60 respectively. In a second (on) state, the first light detector 50 provides the first actuation signal indicating that the rocker switch 30 has been moved to the left (anti-clockwise). In a third (on) state, the second light detector 60 provides the ' second actuation signal indicating that the rocker switch 30 has been moved to the right (clockwise).

Therefore, when a user actuates the switch arrangement 10 by pressing the rocker switch 30 to the left or the right, the first or second light detectors 50 or 60 provide an appropriate actuation signal.

Referring now also to FIG. 5, the rocker switch 30 is a two piece (upper and lower) construction which is retained by way of a snap-fit connection 90. Stubs 92 protrude from the lower piece of the rocker switch 30, and serve as end stops which engage with the PCB 20 when the switch is actuated.

Referring now also to FIGs. 6, 7 and 8 there is shown an alternative switch arrangement 100, comprising a switch housing 120, in which is mounted a push-pull type switch 130. One end of the switch 130 is anchored about a fixing 135, which allows a lever arm 145 of the switch to move pivotally with respect to the fixing 135. 15 An LED 140 is mounted on a surface of the switch housing 120 which is internal with respect to the switch 130. First and second light detectors 150 and 160 respectively are mounted on the surface of the switch housing 120, external to the switch 130. 20 First and second cavities 155 and 165 provide light paths between the LED 140 and the first and second light detectors 150 and 160 respectively. As can be seen from FIG. 8, the first cavity 155 is in a higher horizontal plane than the second cavity 165. 25 In operation, the switch arrangement 200 is actuated as follows. In a nonactuated state, the positions of the first and second cavities 155 and 165 is such that only the first cavity 155 conveys light. Therefore only the first detector 150 provides a signal. 30 When an upward pressure is applied to a lever portion 145 of the switch 140, the positions of the first and second cavities 155 and 165 are such that only the second cavity 165 conveys light. Therefore only the second detector 160 provides a signal. 35 When a downward pressure is applied to a lever portion 145 of the switch 140, the positions of the first and second cavities 155 and 165 are such that neither of them conveys light. Therefore no signals are provided by either the first or the second detectors 150 and 160 respectively. These results are summarised in the table below.

Condition FAzst Detector 150 Second Detector 160 Non-actuation 1 0 Actuated UP 0 1 Actuated DOVvTN 0 0 The spring element 170 ensures that when downward or upward pressure is removed, the switch 130 returns to the non-actuation position shown in FIG. 6.

With a suitably rated LED, and with suitably sensitive light detectors, this arrangement works well despite the fact that in FIG. 7, the LED 140 is mounted in the switch housing 120 close to the cavity 155 and some distance from the cavity 165. Alternatively, a further LED could be provided, or changes in the geometry of the arrangement could be made. 15 It will be appreciated that other alternative embodiments to the one described above are possible. For example, the precise layouts of the optical paths and the arrangements of the LEDs and light detectors could be modified to suit various applications. 20 Furthermore, while the two embodiments mentioned above are directed to two-way switches having first and second actuating positions, it is envisaged that a one-way switch, or a switch having three or more actuating positions could be provided in a similar manner. 25 In such an arrangement, it is envisaged that the pivotal arrangement would be adapted to provide freedom of movement in an appropriate number of directions.

Finally, it is envisaged that an alternative arrangement could be provided for actuation. For example, the first and second light paths 55 and 65 could be arranged such that the first and second light detectors are arranged to indicate actuation upon the absence, rather than the detection of light.

Claims

1. An electronic user operated switch arrangement comprising:

a switch housing; a switch member pivotally mounted in the switch housing and arranged to have a non-actuating position, at least one actuating position and at least one optical path; at least one light detecting arrangement mounted in the housing for detecting light along the at least one optical path and arranged to provide at least one actuating signal in dependence thereon; and illumination means for providing light to illuminate the switch arrangement, wherein the at least one optical path is arranged such that when the switch is in the at least one actuating position, light from the illumination means is incident upon the at least one light detecting arrangement, such that the at least one actuating signal is provided in dependence upon the position of the switch.

2. The switch arrangement of claim 1 further comprising a spring element arranged to provide a spring force to urge the switch towards the nonactuating position.

3. The switch arrangement of claim 2 wherein the spring element is integral with the switch housing.

4. The switch arrangement of any preceding claim wherein the switch is a rocker switch having first and second opposing portions, the rocker switch being arranged to be actuated by applying pressure to at least one of the opposing portions of the switch.

5. The switch arrangement of claim 4 wherein the at least one optical path comprise first and second optical paths which are provided in the first and second opposing portions of the rocker switch respectively.

6. The switch arrangement of any one of claims 1 to 3 wherein the switch is a push-pull switch, arranged to be actuated by raising or lowering a lever end portion of the switch.

7. The switch arrangement of any preceding claim wherein the switch housing incorporates an integral printed circuit board having tracks to which the illumination means and the at least one light detecting arrangement are connected.

8. The switch arrangement of claim 7 further comprising a microcontroller arranged to control the functions of the switch arrangement.

9. The switch arrangement of any preceding claim wherein the 15 illumination means is a light emitting diode.

10. A switching module comprising a switch arrangement of any preceding claim.

11. An electronic user operated switch arrangement substantially as hereinbefore described and with reference to the drawings.