Field of the invention

The invention relates to a switch which is operated by a person or by bringing an object or a body part of a person in close proximity to a sensor or touching said sensor. Such a switch may be a capacitive sensor switch.

Description of the related art

Switches and specifically capacitively operated sensor switches are often used for operating doors in railways and busses or other public transport systems, or for operating machines. The sensor switches are robust, maintenance-free, easy to use, and can be adapted to many different designs.

Sensor switches are often based on a capacitive sensor technology. A capacitive sensor may detect an approaching object and specifically an approaching body part, which may be a hand or a finger, by capacitively coupling an electrical signal to the object. An approaching object may be detected by an attenuation of the signal voltage or by an increasing signal current flowing through the object.

A switch which may be used for unlocking a door in a public transport is disclosed in US 2005/0231147 Al. Here, the switch is designed as an elongated bar which can easily be recognized due to its size. A comparatively compact and disk-shaped device is disclosed in

DE 197 18 807 Cl. Here, a capacitive sensor is mounted to one side of a public transport window. An indicator ring indicating the sensor area of the switch is mounted at the opposing side of the window. The switch is capacitively operated through the window. Summary of the invention

The problem to be solved by the invention is to provide a switch with increased visibility. Such a switch may be recognized from a larger distance or under poor lighting conditions.

Solutions of the problem are described in the independent claims. The depend ent claims relate to further improvements of the invention.

In an embodiment, a switch has a housing including a switching element which may be a mechanical switch. In another embodiment, the switching element includes a sensor which may further include a capacitive and/or optical sensor or which may cover a capacitive and/or optical sensor. Both embodiments may be combined with any of the features described herein. The switching element may be configured for detecting the presence of a body part. The sidewall may be configured to be insensitive against the presence of a body part.

The housing may have a top part and a bottom part. The top part includes a sen sor surface on a top side and opposing thereto a mounting section. Between the sensor surface and the mounting section is a sidewall. The sidewall may have at least one rounded edge or a curved shape.

A switching element is arranged within or under the sensor surface. It may be covered by the sensor surface.

The mounting section may be configured to be mounted to a planar object like a plate which may be a glass plate or a metal structure. The surface of the mount ing object may define a mounting plane.

The bottom part extends from the mounting section in a direction opposing to the sensor surface. The bottom part may be one part with the top part or me chanically separated thereof. The top part may be in a fixed spatial relationship to the bottom part. In an embodiment, the top part is not rotatable against the bottom part in an assembled working configuration. The bottom part may be screwed into the top part for assembly.

The sidewall further comprises at least one lighting window. A plurality of light ing windows may be provided. The lighting windows may be symmetrically ar- ranged. For example, if there are two lighting windows, they may be arranged on opposing sides. If there are three lighting windows, these may be arranged under 120 degrees angles. Four lighting windows may be arranged under 90 degrees angles. Behind the at least one lighting window and within the housing is at least one light source which radiates light to the outside of the switch. The light sources may be arranged such that light is radiated on a surface on which the switch is mounted. This surface may be in the mounting plane. The surface may reflect the light and may provide a marking of the switch and/or a switch ap pearance which is larger than the switch itself. In addition, any other part of the housing, e.g. the switching element area may emit light. The emitted light may vary in color and intensity and over time.

The at least one lighting window may protect the light source from environmen tal influences and may provide a mechanical and/or electrical shield. It may be a lens or may comprise at least one lens or lens structure, for example a Fresnel- lens or parts thereof. The housing has a mounting section, which is configured to be mounted to a sur face. The top of the surface defines a mounting plane to which the housing (e.g. the switch) may be mounted. Preferably, the switching element has a planar sur face which preferably is parallel to the mounting plane.

The housing may be a one piece housing with a preferably threaded shaft for holding the switching element. In another embodiment, the housing comprises a top part and a bottom part which may be mounted distant from each other. The top part may be in electrical and/or optical communication with the bottom part. In an embodiment, the at least one light source is integrated into the switching element housing. It may also be integrated into an outer ring. In an embodiment, the switching element housing is a two-part embodiment, where the two parts may be mounted at different sides of a window. Here, the switching element and/or sensor electronics may be provided in a first part being on one side of the window, whereas the at least one light source is in another part, which may be an outer ring on the other side of the window. Also a light source for lighting the switching element may be provided. Any of the light sources may be LEDs, OLEDs or other light-emitting devices which are supplied by electrical energy which may be inductively or capacitively coupled from the first part. There may be a coil within the outer ring which is coupled to a coil in the first part to couple the elec tric energy between the two parts. Alternatively, the light may be emitted by at least one light source which may comprise a LED or other light-emitting compo nents in the first part and guided for example by a lens system through the glass of the window into the second part like an outer ring where it is deflected to the at least one lighting window to the outside of the housing.

The light sources may have different and/or multiple colors which may indicate different states of the switch or different types or kinds of switches.

Description of Drawings

In the following the invention will be described by way of example, without limi tation of the general inventive concept, on examples of embodiment with refer ence to the drawings.

Figure 1 shows a top view of an embodiment.

Figure 2 shows a perspective view of an embodiment. Figure 3 shows an embodiment mounted into a window.

Figure 4 shows a two-part embodiment.

Figure 5 shows an exemplary light distribution in a top view. Figure 6 shows an exemplary light beam of the switch.

In Figure 1, a top view of an embodiment is shown. A switch 100 comprises a preferably planar switching element 110 or a planar sensor which is sensitive to an approaching object which may be a hand or a finger of a person. Preferably, the switching element 110 is a mechanical or electronic switching device or a a capacitive and/or optical proximity sensor. The switching element preferably has a planar surface. There may be an outer ring 120 surrounding the switching ele ment 110. A plurality of lighting windows 131, 132, 133, 134 are provided cir cumferentially to the switching element and may be integrated into the outer ring 120. Preferably, the lighting windows are arranged symmetrically. In the embodiment shown herein, four lighting windows are provided which are ar ranged under angles of 90 degrees between adjacent windows. The windows have an elongated shape but they may have any other shape, like a circular shape or a rectangular slot, or any other shape which is suitable for providing a light output. Preferably, the lighting windows comprise a material which may conduct light of a suitable wavelength. Not shown in this Figure (but in Fig. 5) are light sources 151 - 154 which provide light which exits through the lighting win dows. Preferably, at least one light source is provided within the switch and be hind each of the lighting windows. The light sources may be individually control lable to generate various light patterns. In an embodiment, the lighting windows and/or the sensor surface exclusively are configured to emit light. The outer ring, except for the windows, may include a non-light transmissive and/or a light absorbing material.

In Figure 2, a perspective view of an embodiment is shown. In addition to the top of the switch with sensor surface 181, sidewall 183, and mounting section 182, which may have a planar surface configured to be mounted to a surface which may be the top surface of a mounting plate, which will be shown in the next fig ure. The top surface also defining a mounting plane. The components of the bot tom part 102 are also shown. There may be a shaft 210 which may comprise switching mechanics or electronics or further electronic devices required for ca pacitive and/or optical detection of an object in close proximity to the sensor 110. The shaft may have an outer thread which matches to a fastening nut 220. At the housing, there may also be a signal connector 230 for electrical connec tions providing power to the switch and coupling of a detection signal. The con nector may have an outer thread 231 and connecting pins 232 which are on the bottom side in this embodiment and cannot be seen.

In Figure 3, an embodiment is shown, which is mounted into a plate 300 which may be a window or a glass plate. The top side of the plate 300 may be defining the mounting plane 185 which is in contact with the mounting section 182. It may also be a window comprising multiple parallel glass plates. The fastening nut 220 may be rotated to hold the switch within a hole of the window. The mount ing plane is the top plane of the plate 300, which preferably corresponds to an under side of the top part of the housing containing the switching element.

In Figure 4, a two-part embodiment is shown. Here, the switch 100 comprises a top part 101 which is attached on one side of the plate 300, which may be a win dow, and a bottom part 102 which is mounted opposing to the top part 101 on the other side of the plate 300, which may be a window. The advantage of this embodiment is that there is no hole required in the window. The disadvantage is that coupling of electrical signals and/or sensing of an object may be somewhat more complicated due to the higher coupling distance through the plate, which may be a window, and coupling of light or electrical power for light sources from the second part 102 to the first part 101 may require additional effort as dis closed above. The mounting plane is the top plane of the plate BOO, which pref erably corresponds to an under side of the top component 101.

The top part 101 may have a width or a diameter 187 which is larger than its height 188. The ratio width/height may be less than one of 10, 8, 6, 5, 4, 3, 2. The top part 101 may have a circular shape. It may have a diameter 187 which is larger than its height 188. The ratio diameter/height may be less than one of 10,

8, 6, 5, 4, 3, 2.

In Figure 5, an exemplary light distribution of the switch is shown in a top view.

In addition, here only for demonstration purposes, the light sources 151, 152, 153, 154 are indicated. They cannot be seen, as they are embedded into the out er ring 120 of the switch. The light sources radiate light through the lighting win dows 131, 132, 133, 134 and generate light beams 141, 142, 143, 144. These light beams are preferably directed under a small angle to the surface on which the switch is mounted, as will be shown in the next Figure. In Figure 6, an exemplary light beam of the switch is shown. Here, light emitted through the lighting window 132 forming a light beam 142 is directed under a small angle towards the plate 300 which may be a window or a metal plate. The light is reflected by the plate 300 and may be seen by a person, such as a person operating the switch. The best results are provided if the surface of the plate is light reflecting such that the light emitted through the window 132 is emitted in a direction orthogonal to the plate, such as indicated by arrow 149. List of reference numerals

100 switch

101 top part of housing

102 bottom part of housing 110 switching element

120 outer ring

131 - 134 lighting windows

141 144 light beams

149 direction of reflected light

151 - 154 light sources

181 sensor surface

182 mounting section

183 sidewall

185 mounting plane

187 width or diameter

188 height

210 shaft

220 fastening nut

230 signal connector

231 outer thread

232 connecting pins

300 mounting plate