US 3,986,335 A · Electronic watch module and its method of fabrication

Abstract

An electronic watch module is fabricated by mounting a semiconductor integrated circuit chip on a metal lead frame. Connectors are utilized to connect the circuit to selected lead frame conductors. The semiconductor chip incorporates all of the electronic circuitry necessary to drive a display with decoded timekeeping signals. The lead frame includes selectively positioned conductors for connection of a display, a variable capacitor, oscillator crystal and battery contacts. The lead frame is plastic encapsulated with the plastic being formed to completely seal the integrated circuit and connectors while providing mechanical support cavities for the display, capacitor, crystal and batteries. Openings are also provided in the plastic within the cavities and opposite the cavity formations exposing the selectively positioned conductors so that the display, capacitor and crystal may be electrically connected to the lead frame. Lead frame conductors also extend about the periphery of the module for connection of time setting and/or display demand switches to the battery and circuit.

Claims57

Dependent claims

A circuit module for an electronic watch comprising:

a. display means responsive to electrical signals for displaying time;
b. an integrated circuit chip having circuitry for driving said display means with decoded electrical timekeeping signals;
c. a metal lead frame having a plurality of lead conductors ohmically coupling said display means to said integrated circuit chip;
and
d. encapsulating means completely encapsulating said integrated circuit chip, said encapsulating means having a cavity selectively positioned with respect to said plurality of lead conductors with said display means being supported within said cavity.

2 more elements

A circuit module for an electronic watch comprising:

a. display means responsive to electrical signals for displaying time;
b. an integrated circuit chip having circuitry for driving said display means with decoded electrical timekeeping signals;
c. an oscillator crystal;
d. a capacitor device;
e. a metal lead frame extending essentially in a single plane, said lead frame including:
i. a first plurality of lead conductors ohmically coupling said display means to said integrated circuit chip,
ii. a second plurality of lead conductors ohmically coupling said oscillator crystal to said integrated circuit chip,
iii. a third plurality of lead conductors ohmically coupling said capacitor device to said integrated circuit chip, and
iv. a fourth plurality of lead conductors for ohmically coupling battery means to said integrated circuit chip;
and
f. encapsulating means completely encapsulating said integrated circuit chip, said encapsulating means having:
i. a first cavity selectively positioned with respect to said first plurality of lead conductors with said display means being supported within said first cavity,
ii. a second cavity selectively positioned with respect to said second plurality of lead conductors with said oscillator crystal means being supported within said second cavity,
iii. a third cavity selectively positioned with respect to said third plurality of lead conductors with said capacitor device being supported within said third cavity, and
iv. at least one additional cavity selectively positioned with respect to said fourth plurality of lead conductors for supporting at least one battery within said at least one additional cavity.

12 more elements

A circuit module for an electronic watch comprising:

a. a metal lead frame having upper and lower opposite major surfaces;
b. an integrated circuit chip mounted on the upper surface of said lead frame and selectively ohmically coupled to lead conductors of said lead frame, said integrated circuit chip having circuitry for driving a display means with decoded electrical timekeeping signals, said lead frame including:
i. a first plurality of lead conductors for ohmically coupling a display means to said integrated circuit chip,
ii. a second plurality of lead conductors for ohmically coupling an oscillator crystal to said integrated circuit chip, and
iii. a third plurality of lead conductors for ohmically coupling a capacitor device to said integrated circuit chip;
and
c. encapsulating means completely encapsulating said integrated circuit means, said encapsulating means having:
i. a first cavity selectively positioned with respect to said first plurality of lead conductors with a portion of said first plurality of lead conductors being exposed within said first cavity, said first cavity for mechanically supporting said display means in a position such that said display means is in ohmic contact with said portion of said first plurality of lead conductors,
ii. a second cavity selectively positioned with respect to said second plurality of lead conductors with a portion of said second plurality of lead conductors being exposed within said second cavity, said second cavity for mechanically supporting said oscillator crystal in a position such that said oscillator crystal is in ohmic contact with said portion of said second plurality of lead conductors, and
iii. a third cavity selectively positioned with respect to said third plurality of lead conductors with a portion of said third plurality of lead conductors being exposed within said third cavity, said third cavity for mechanically supporting said capacitor device in a position such that said capacitor device is in ohmic contact with said third plurality of lead conductors.

7 more elements

An electronic watch comprising:

a. a watch housing having upper and lower major surfaces and a cavity therein extending from said upper major surface to said lower major surface with a lens member sealing said cavity at said upper major surface;
b. a circuit module including:
i. display means responsive to electrical signals for displaying time,
ii. an integrated circuit chip having circuitry for driving said display means with decoded electrical timekeeping signals,
iii. an oscillator crystal,
iv. a variable capacitor device,
v. a metal lead frame including a first plurality of lead conductors ohmically coupling said display means to aid integrated circuit chip, a second plurality of lead conductors ohmically coupling said oscillator crystal to said integrated circuit chip, a third plurality of lead conductors ohmically coupling said capacitor device to said integrated circuit chip, a fourth plurality of lead conductors for ohmically coupling battery means to said integrated circuit chip, and a fifth plurality of lead conductors for ohmically coupling one or more switch means to said integrated circuit chip, and
vi. encapsulating means completely encapsulating said integrated circuit chip, said encapsulating means having a first cavity selectively positioned with respect to said first plurality of lead conductors with said display means being supported within said first cavity, a second cavity selectively positioned with respect to said second plurality of lead conductors with said oscillator crystal means being supported within said second cavity, a third cavity selectively positioned with respect to said third plurality of lead conductors with said capacitor device being supported within said third cavity, and at least one additional cavity selectively positioned with respect to said fourth plurality of lead conductors for supporting at least one battery within said at least one additional cavity, said circuit module being positioned within the cavity of said watch housing with said display means being visible from outside of said housing through said lens member;
c. at least one time setting and/or display demand switch mounted in said housing and ohmically coupled to said fifth plurality of lead conductors;
and
d. a removable back member at least coincidental with said at least one additional cavity for sealing the cavity of said watch housing at said lower major surface.

8 more elements

A method of fabricating an electronic watch module comprising:

a. mounting a semiconductor integrated circuit chip having circuitry for driving a display means with decoded electrical timekeeping signals on a mounting pad of a metal lead frame, said lead frame including a first plurality of lead conductors for ohmically coupling said display means to said integrated circuit chip, a second plurality of lead conductors for ohmically coupling an oscillator crystal to said integrated circuit chip, a third plurality of lead conductors for ohmically coupling a capacitor device to said integrated circuit chip, and a fourth plurality of lead conductors for ohmically coupling one or more batteries to said integrated circuit chip;
b. bonding wire connectors between terminal pads on said integrated circuit chip and selected ones of said lead frame conductors;
c. placing the lead frame between upper and lower molds having mold cavities;
d. injecting a plastic material into the cavities of said upper and lower molds to completely encapsulate said integrated circuit chip, the upper mold being formed to provide in the injected plastic a first cavity extending to one surface of said first plurality of lead conductors for the mechanical support of said display and first and second openings respectively exposing a portion of one surface of said second and third pluralities of lead conductors and the lower mold being formed to provide in the injected plastic second and third cavities for the mechanical support of said crystal and said capacitor extending to the opposite surface of said second and third pluralities of lead conductors respectively, one or more battery cavities and a third opening exposing a portion of the opposite surface of said first plurality of lead conductors;
e. removing the encapsulated lead frame from said mold;
f. inserting a display means in the display cavity and ohmically bonding said display means to said lead frame through said third opening;
g. inserting an oscillator crystal in said second cavity and ohmically connecting said oscillator crystal to said second plurality of lead conductors through said first opening;
and
h. inserting said capacitor device in said third opening and electrically connecting said capacitor device to said third plurality of lead conductors through said second opening.

6 more elements

A method of fabricating an electronic watch module comprising:

a. selectively positioning a semiconductor integrated circuit chip having circuitry for driving a display means with decoded electrical timekeeping signals upside down on a metal lead frame, said lead frame including a first plurality of lead conductors for ohmically coupling a display means to selected terminal pads of said integrated circuit chip, a second plurality of lead conductors for ohmically coupling an oscillator crystal to selected terminal pads of said integrated circuit chip, a third plurality of lead conductors for ohmically coupling a capacitor device to selected terminal pads of said integrated circuit chip, and a fourth plurality of lead conductors for ohmically coupling one or more batteries to selected terminal pads of said integrated circuit chip;
b. thermocompression bonding the terminal pads on said integrated circuit chip to contacted portions of said lead frame conductors;
c. placing the lead frame between upper and lower molds having mold cavities;
d. injecting a plastic material into the cavities of said upper and lower molds to completely encapsulate said integrated circuit chip, the upper mold being formed to provide in the injected plastic a first cavity extending to one surface of said first plurality of lead conductors for the mechanical support of said display and first and second openings respectively exposing a portion of one surface of said second and third pluralities of lead conductors and the lower mold being formed to provide in the injected plastic second and third cavities for the mechanical support of said crystal and said capacitor extending to the opposite surface of said second and third pluralities of lead conductors respectively, one or more battery cavities and a third opening exposing a portion of the opposite surface of said first plurality of lead conductors;
e. removing the encapsulated lead frame from said mold;
f. inserting a display means in the display cavity and ohmically bonding said display means to said lead frame through said third opening;
g. inserting an oscillator crystal in said second cavity and ohmically connecting said oscillator crystal to said second plurality of lead conductors through said first opening;
and
h. inserting said capacitor device in said third opening and electrically connecting said capacitor device to said third plurality of lead conductors through said second opening.

6 more elements

Dependencies are inferred from the claim text.

Electronic watch module and its method of fabrication

Life of this patent

Electronic watch module and its method of fabrication

Life of this patent

Abstract

Claims57