| 摘要 |
A switch for a sanitary device such as an electric shower includes a support 12, a light source 14 mounted on the support, a light sensor 16 mounted on the support adjacent the light source, and a translucent front wall 40 opposite the support. The light source 14 is arranged to irradiate light towards and through the front wall 40. The light sensor 16 is arranged to detect light returning through the front wall. The switch further includes an opaque shroud 24 defining a first light channel 28 extending with substantially parallel sides from the front wall 40 to the support 12 and having one end at the support enclosing substantially only the light source 14 and at least a light irradiating portion thereof. The shroud 24 is thus configured so as substantially to prevent light scattering from the light irradiating portion of the light source between the shroud and the support. The shroud 24 further defines a second light channel 30 extending with substantially parallel sides from the front wall to the light sensor. The first channel 28 also restricts light transmission to be more columnar in nature. |
