Diaphragm Type Pushbutton Setting Switch With Fixed Contact Semiconductor Substrate Support

Abstract

Disclosed is a setting switch for electronic watches comprising a rigid contact pin mounted on the electronic substrate of the watch and a flexible spring contact mounted in an aperture of the watch case in registration with the rigid contact. A flexible diaphragm and retaining ring mounted over the spring contact in the aperture form a moisture seal with the watch case.

Description

The present invention pertains to switches in general and, more particularly to a non-latching pressure sensitive switch of a size and configuration adapted for utilization as a setting switch for an electronic wrist watch.

Battery powered electronically controlled wrist watches of various types have been described in the literature and are commercially available. Further, battery powered wrist watches having a liquid crystal display have been proposed. One of the difficulties in such wrist watches pertains to time setting mechanisms. These time setting switches must be of a size which is compatible with wrist watch configurations and also must be sealed to protect the interior of the watch enclosure.

Accordingly, an object of the present invention is the provision of a time setting switch for use with an electronically controlled wrist watch.

A further object of the invention is the provision of an inexpensive wrist watch time setting switch which is fully sealed.

In accordance with the invention, a compact, fully sealed time setting switch is provided. The switch includes a flexible diaphragm mounted in a recess in the case of the wrist watch. The diaphragm communicates with a contact spring which may be deflected responsive to flexing, i.e., depressing the diaphragm. In its deflection position, the spring makes contact with a conductive post which is ohmically secured to a contact pad of a suitable support substrate. Preferably, the conduct post is secured to a semiconductor substrate in which the electronic control circuitry of the wrist watch is defined. The contact post is electrically connected to logic circuitry of the electronic wrist watch to enable setting of the time. In a preferred embodiment, the flexible diaphragm has a raised central portion which extends nearly flush with the back of the wrist watch case such that normal contact of the watch with the wrist of the wearer does not provide sufficient pressure to activate the contact spring .

Other objects and advantages of the present invention will be apparent upon reading the following detailed description of illustrative embodiments of the invention in conjunction with the drawings wherein:

FIG. 1 is a pictorial illustration of the switch in accordance with the present invention;

FIG. 2 is a cross-sectional illustration of a portion of an electronic wrist watch embodying the switch of the present invention;

FIG. 3 illustrates one embodiment of an electronic wrist watch having four switches for setting independently the hours, minutes, seconds and date; and

FIG. 4 schematically and in logic block diagram format illustrates connection of the switches in FIG. 3 to the electronic watch control circuitry.

With reference now to the drawings, and particularly with reference to FIGS. 1 and 2, a time setting switch in accordance with the invention includes a substrate 10 for supporting a contact or conductive post 12 which may, by way of example, comprise brass. Preferably, the substrate 10 has an aperture 14 for receiving a lower portion 16 of the contact 12. The contact is secured to the substrate 10 in an ohmic connection. The contact is then connected to control circuitry of the electronic wrist watch. The contact 12 preferably has an expanded portion 18 for mounting on the surface of the substrate 10.

In a preferred embodiment, the substrate 10 is a semiconductor body which also contains the integrated control circuitry of the electronic wrist watch. In this embodiment, the contact 12 is ohmically connected to an expanded contact (not shown) on the substrate surface.

The case or housing of the wrist watch is illustrated at 20 and may, by way of example, comprise stainless steel. Preferably, the switches of the present invention are mounted in the back plate of the wrist watch case; that is, the plate which would contact the wrist of the wearer, although any suitable mounting arrangement may be utilized. An aperture 22 is formed to extend through the wrist watch case at each location where a switch 12 is to be mounted. The aperture 22 is defined to have a lip 24 for supporting the contact spring 26, the flexible diaphragm 28 and the retaining ring 30. The mounting configuration is most clearly illustrated in FIG. 2.

The contact spring 26 preferably is defined by a circular ring having a flexible portion 25 extending into the center region defined by the ring. The center region 25 is preferably substantially flush with the top surface of the ring. The contact spring 26 mounts on the lip 24 defined around the peripheral region of the aperture 22. Preferably, the contact spring comprises beryllium-copper alloy 25. Other suitable materials may be utilized, however, if desired. A flexible diaphragm 28 is mounted in the aperture 22 and is supported by the ring portion of the contact spring 26. Preferably, the exposed surface of the diaphragm has a raised portion 29 in the central region. Responsive to pressure being applied to the raised portion 29, the diaphragm flexes in the center portion and depresses the flexible portion 25 of the contact spring. A suitable material for the flexible diaphragm is polyurethane. Other flexible materials may be utilized if desired. It is preferred that the diaphragm be substantially non-porous such that it can function as a seal.

A retaining ring 30 forms a seal with the diaphragm. Preferably, the retaining ring 30 is stainless steel and is press fitted to the aperture 22. The upper surface of the retaining ring 30 is substantially flush with the exposed surface of the wrist watch case 20. The raised portion 29 of the flexible diaphragm is structured to be substantially flush with the wrist watch case such that no substantial pressure is exerted on the raised portion 29 during normal operation of the wrist watch.

The contact conductive post 12 extends from the substrate 10 into close proximity to the center portion of the aperture 22 directly underlying the region 25 of the contact spring. In normal operation, the contact pin 12 does not make electrical connection to the region 25 of the contact spring. Responsive to pressure exerted upon the flexible diaphragm 28, however, the flexible portion 25 is depressed sufficiently to electrically contact the contact pin 12 and provide an enable signal to the electronic wrist watch circuitry to increment the display, thereby providing a reset capability.

With reference to FIG. 3, there is pictorially illustrated a typical liquid crystal wrist watch display format. The face of the wrist watch is illustrated at 32. The upper central display regions illustrated generally at 34 may, for example, comprise a display for the date. The left-hand portion of the display 36 illustrates hours, the right-hand segments 38 illustrate minutes, and the bottom-most segments 40 may illustrate seconds. For this type of a display four of the time setting switches of the present invention are utilized. These switches are illustrated by dashed lines 42. It may be seen that one switch is required for each display function in order to be able to independently set the respective displays. In this preferred embodiment, the setting switches are accessed from the back plate of the wrist watch. Since each setting switch 42 directly underlies the display function to be set, user convenience is maximized. The setting may be accomplished by lifting an edge of the wrist watch and depressing the raised portion 29 of the flexible diaphragm. The logic circuitry of the wrist watch effects indexing of the data displayed one count per second. Thus, a maximum of 60 seconds is required to set any element of the display.

With reference to FIG. 4, there is illustrated schematically and in logic block diagram format connection of the switches in accordance with the present invention to the electronic watch circuitry. When a selected switch is depressed, the supply voltage V.sub.CC is applied to logic circuitry 44. The logic circuitry enables the drive circuitry illustrated generally at 46 to increment the display 48. The logic circuitry also provides an inhibit function such that one function element may be reset without incrementing the subsequent element. For example, if the minutes segments of the display are reset past sixty, the inhibit function would preclude the hours display from incrementing to the next hour. Circuitry for effecting such control is described in detail with reference to copending application Ser. No. 264,212 assigned to the assignee of the present invention and filed concurrently herewith.

While the present invention has been described in detail with respect to an illustrative embodiment, it will be apparent to those skilled in the art that various changes may be made without departing from the scope of spirit of the invention.

Claims

What is claimed is:

1. An electrical switch comprising in combination:

a. an enclosure defining an aperture extending through one surface thereof;

b. a flexible first electrical contact mounted within said aperture;

c. a flexible diaphragm positioned adjacent said flexible contact;

d. means for sealing the aperture in said enclosure comprising a retaining ring engaging the sidewalls of said aperture and the surface of said flexible diaphragm in sealing relationship; and

e. a second electrical contact means comprising a conductive post spaced from said first contact and mounted to a contact region of a semiconductor substrate which is mounted within said enclosure whereby, responsive to displacement of said flexible diaphragm, electrical contact is established between first and second contact.

2. An electrical switch for an electronic wrist watch comprising in combination:

a. a wrist watch case defining an aperture through the back place thereof, the region of said case adjacent said aperture defining a recess extending from the back surface, thereby defining a support lip around said aperture;

b. a contact spring having a first flexible central contact, said spring secured to said support lip within said recessed region;

c. a flexible diaphragm mounted within said recess region and adjacent said flexible contact, said diaphragm having a raised central portion extending substantially flush with the surface of said back plate,

d. a retaining ring engaging the sidewalls of said aperture and the surface of said flexible diaphragm in sealing relationship; and

e. a second contact mounted within said case and to a contact pad of a semiconductor substrate, said second contact extending into said aperture in close proximity to said first contact, whereby responsive to displacement of said flexible diaphragm electrical contact is established between said first and second contacts.