Lucas Industries Limited

Lucas Duralith Corporation

Gregory B Demeo

Henry E Molvar

David R Bergerson

Disclosed is the backlit display and/or backlit keyboard display which have a controlled level of illumination at the surface thereof. Where such switch and/or display are illuminated by a light emitting diode, the present invention interposes an optical filter between the light emitting diode and the surface of the cover. The optical filter contains a pattern thereon having a variable density distribution of opaque material which in a preferred embodiment is densest in the area closest to the light emitting diode and decreases in density in areas away from the light emitting diode. In a preferred embodiment the optical filter is a 'negative' of the illumination without a filter present. The result in both the switch and display embodiments is a substantially constant level of illumination across the surface of the cover. Further disclosed is at least one slot in translucent layers which may be incorporated in a switch or display which reduces 'crosstalk' between switches and/or displays. Additionally the use of a reflective material as the optical filter, in combination with and separated from a reflective layer near the LED by a separator layer, provides increased illumination of the display or switch.

Light distribution for illuminated keyboard switches and displays

A switch assembly comprising a housing, a rigid operating member mounted for movement relative to the housing and accessible to an operator, an electrical contact operable by movement of the operating member from a rest position to an operative position relative to the housing, a flexible seal between the operating member and the electrical contact and capable of transmitting operative movement of the operating member to the contact while preventing passage of moisture and other contaminants from the region of the operating member to the contact, and, a limit preventing movement of the operating member relative to the contact beyond the position at which the contact is operated. The switch can include further operating members and associated contacts and limits carried by the housing and if desired the assembly can incorporate a heater for heating the operating member region of the assembly.

Switch assembly

Disclosed is a keypad for use with compact and portable cellular telephone systems in which each key is backlit. A partially translucent overlay layer of flexible material includes a raised key. Under the key, in a preferred embodiment, is an actuation layer, which, during operation, is depressed downward by the key. Below the actuation layer, is a tactile feedback layer including a dome for each key, in which, after being depressed to a predetermined degree, the dome inverts causing a conductor located below the dome to short conductive traces on a substrate upon which the keypad is mounted. In a preferred embodiment, the keys are backlit by a light source extending through the substrate upon which the keypad is mounted. The tactile feedback layer includes a structure for reducing pressure on the light source when the tactile layer is in the inverted condition, resulting in a thinner keypad with a brighter backlit key and a longer life light source.

Backlit tactile keyboard with improved tactile and electrical

Disclosed is a keypad for use with compact and portable cellular telephone systems in which each key is backlit. A partially translucent overlay layer of flexible material includes a raised key. Under the key, in a preferred embodiment, is an actuation layer, which, during operation is depressed downward by the key. Below the actuation layer, is a tactile feedback layer including a dome for each key, in which, after being depressed to a predetermined degree, the dome inverts causing a conductor located below the dome to short conductive traces on a substrate upon which the keypad is mounted. In a preferred embodiment, the keys are backlit by a light source extending through the substrate upon which the keypad is mounted. The tactile feedback layer includes a structure for reducing pressure on the light source when the tactile layer is in the inverted condition, resulting in a thinner keypad with a brighter backlit key and a longer life light source.

Growing community of inventors

Lydeborough, NH, United States of America

Gregory B Demeo