Back lit keypad

A keypad which includes a pad portion for mounting on a circuit board, characterized by:

• a shell that includes a key portion having a top wall with a lower surface and having side walls with lower ends and with inner surfaces, said key portion walls forming a downwardly opening cavity, and said shell having flexible coupling portions that connect said side lower ends to said pad portion;
• a quantity of a light transmitting material lying in said cavity, said quantity of light transmitting material having a top face which lies substantially against said lower surface of said shell top wall;
• said shell top wall having at least a first opening therein representing a character, with said first opening being at least translucent to light that has passed through said quantity of light transmitting material;
• and
• said top wall, side walls, flexible coupling portions, and pad portion being integral and formed of an opaque elastomeric material, with substantially the entire thickness of said pad portion being of said opaque elastomeric material.

A backlit keyboard assembly comprising:

• a board assembly which includes a board, a plurality of switches on said board, and a light source positioned to illuminate a region immediately above said board;
• a keypad of opaque elastomeric material which includes a pad portion lying on said board and a plurality of spaced key portions each lying over a corresponding one of said switches, each of said key portions having a top wall;
• each of said key portions further including side walls, with said top and side walls forming a downwardly opening cavity, and with said top and side walls of each key portion being integral with said pad portion, and including a plurality of separate quantities of light transmitting second material each lying in a corresponding one of said cavities with each quantity of second material having a lower end forming a switch operator which transmits force to operate a corresponding one of said switches when the top wall of a corresponding key portion is depressed, and with the lower end of each quantity of second material positioned to be illuminated by said light source to pass light upwardly through the corresponding quantity of light transmitting material;
• and
• said top wall of each of a plurality of said key portions having a cutaway region defining a character, for transmitting light passing up through the corresponding quantity of second material;
• said plurality of quantities of second material are separate from one another;
• said pad portion connecting said key portions, with said pad portion and said key portions being formed of opaque elastomeric material.

A method for forming a keypad characterized by:

• forming a keypad shell of elastomeric opaque first material which includes at least a first key with a first key top and first key sides extending largely vertically from said first key top and forming a first cavity within said first key sides and first top, and with a pad extending largely horizontally from near the bottom of said first key sides, said first key top having upper and lower faces;
• installing a quantity of light transmitting second material in said first cavity wherein said quantity of second material has a top face, so said top face lies facewise against the lower face of said first key top to support it;
• and
• removing selected regions of said first key top to leave an opening therein representing a character, with said opening being translucent so it can pass light that has passed up through said quantity of second material.