Illuminable push button switching unit

• US 5,655,826 A
• Filed: 03/22/1996
• Issued: 08/12/1997
• Est. Priority Date: 03/29/1995
• Status: Expired due to Term

• Current Assignee: Shin-Etsu Polymer Company Limited (Shin-Etsu Chemical Company Limited)
• Original Assignee: Shin-Etsu Polymer Company Limited (Shin-Etsu Chemical Company Limited)
• Inventors: Kouno, Fumio, Nakano, Sadao
• Primary Examiner(s): Dority, Carroll B.
• Application Number:
  US08/621,027
• Time in Patent Office: 508 Days
• Field of Search: 362/24, 362/88, 362/84, 200/314
• US Class Current: 362/24
• CPC Class Codes: H01H 13/702 with contacts carried by or formed from layers in a multilayer structure, e.g. membrane switches
• CPC Class Codes: H01H 2219/014 LED
• CPC Class Codes: H01H 2219/038 ambient light dependent
• CPC Class Codes: H01H 2219/044 Edge lighting of layer
• CPC Class Codes: H01H 2219/052 Phosphorescence

Abstract

An improved push button switching unit is proposed of which the indicia on the key top is recognizable even in a dark place. Namely, a phosphorescent layer emitting phosphorescence even in a dark place is formed on the upper surface of the key top to provide recognizability of the indicia and further the switching unit is provided with a light sensor means and a light source which is lighted when the ambient lightness is low as detected by the sensor means. When the switching unit is used continuously in a dark place, the light source repeats cycles of a lighting period, in which the phosphorescent layer accumulates the energy of light, and a dark period, in which the phosphorescent layer emits phosphorescence by means of the accumulated energy, so that the power consumption for lighting the light source can be saved.

Claims

1. An illuminable push button switching unit comprising, as encased in a case, an assembly of a circuit board and a covering member made from a light-transmitting material, which consists of a base plate, key top, riser part to connect the base plate and the key top forming a dome-like protrusion and a movable contact point on the lower surface of the key top, having an indicia formed on the upper surface of the key top, and mounted on one surface of the circuit board:

which further comprises;

a phosphorescent layer containing a phosphorescent pigment, capable of emitting phosphorescent light of such an intensity that the indicia on the key top is recognizable with the phosphorescent light emitted therefrom, in an area corresponding to the indicia on the key top;

a light sensor means in the case for detecting the ambient lightness; and

a light source in the case capable of illuminating the phosphorescent layer, which is lighted on and out by the output signals of the light sensor means.

2. The illuminable push button switching unit as claimed in claim 1 in which the phosphorescent layer is covered with an indicia-forming layer of a colored or light-shielding material having an openwork in the form of the indicia.

3. The illuminable push button switching unit as claimed in claim 1 which further comprises a control circuit capable of controlling lighting of the light source to repeat cycles consisting of a lighting period and a dark period when the ambient lightness is low.

4. An illuminable push button switching unit comprising, as encased in a case, an assembly of a circuit board, a covering member made from a light-transmitting material, which comprises a key top, a sheet member, a presser head and a light-conducting plate, and mounted on one surface of the circuit board and a diaphragm below the presser head:

which further comprises;

a phosphorescent layer containing a phosphorescent pigment, capable of emitting phosphorescent light of such an intensity that the indicia on the key top is recognizable with the phosphorescent light emitted therefrom, in an area corresponding to the indicia on the key top;

a light sensor means in the case for detecting the ambient lightness; and

a light source in the case capable of illuminating the phosphorescent layer, which is lighted on and out by the output signals of the light sensor means.

5. The illuminable push button switching unit as claimed in claim 4 in which the phosphorescent layer is covered with an indicia-forming layer of a colored or light-shielding material having an openwork in the form of the indicia.

6. The illuminable push button switching unit as claimed in claim 4 which further comprises a control circuit capable of controlling lighting of the light source to repeat cycles consisting of a lighting period and a dark period when the ambient lightness is low.