US 3925978 A
A time correcting arrangement for an electronic wrist watch wherein time correcting switches for correcting the digital display of time are isolated from the circuit for driving the digital display by a control circuit adapted to pass the signal represented by the time correcting switches only upon the selective actuation of a correcting switch coupled to said control circuit.
Claims available in
Description (OCR text may contain errors)
United States Patent 11 1 Naito Dec. 16, 1975 TIME CORRECTING ARRANGEMENT FOR 3.733.810 5/1973 Girard 513/853 ELECTRONIC WRIST WATCHES 1761152 10/1973 MartZU...
3768 247 l0/l973 Fujita 58/85.5 X Inventor: Okito Naito, Suwa, Japan 3,810,356 5/1974 Fujita 58/85.5 Assigneez Kabushiki Kaisha Suwa Seikosha, 3.823545 7/l974 VittoZ et al. 58/8515 X Tokyo, Japan  Filed: July 31, 1973 Primary E.\'aminerEdith Simmons Jackmon Attorney, Agent, or Firm-Blum, Moscovitz, Friedman ] Appl. No.. 384,339 & Kaphm  Foreign Application Priority Data July 31, 1972 Japan 47-76697  ABSTRACT  US. Cl. 58/23 R; 58/50 R, 58/85.5;
328/14 A time correcting arrangement for an electronic wrist  Int. CL? G04C 3/00; GO4B l9/30; watch wherein time correcting switches for correcting G04B 27/00; H038 l9/OO the digital display of time are isolated from the circuit  Field of Search 58/23 R, 23 A, 50 R, 85.5; for driving the digital display by a control circuit 328/14 adapted to pass the signal represented by the time correcting switches only upon the selective actuation of a  References Cited correcting switch coupled to said control circuit.
UNITED STATES PATENTS 3,664,118 5/1972 Walton 58/50 R 5 Claims, 8 Drawing Figures US. Patent Dec. 16,1975 SheetlofZ 3,925,978
5 /2 53557 PRIOR ART TM"- 1 3 6 1 m2 i i Q Q fyez iz ia 2 C/ZCU/KS TT 7 T Q64l/z if D/V/DEQ F1622 PRIOR ART 5 /2:35 V57 H M s FIG 3 F764 PRIOR ART PRIOR ART US. Patent Dec. 16, 1975 Sheet 2 of2 3,925,978
5 /2.'3557 F- FIG 5 u 1k M PRIOR ART I 4- "(Yaw/75% 9: 1 J 5 64,4:
(rm read 3/64 44 TIME CORRECTING ARRANGEMENT FOR ELECTRONIC WRIST WATCHES BACKGROUND OF THE INVENTION This invention relates to an electronic wrist watch having a, digital display device, for example, of the liquid crystal type, and more particularly, to the time correcting arrangement for such wrist watches.
Such wrist watches may be provided with manually operated switches for correcting the digital display of time. Such switches are subject to accidental actuation, causing errors in the displayed time, and further, where a time correcting switch is partially actuated so as to bring the contacts close together, noise may be produced in the electronic circuitry driving the digital display, interfering with the proper operation thereof.
SUMMARY OF THE INVENTION Generally speaking, in accordance with the invention, an electronic wrist watch is provided including a high frequency time standard oscillator, multi-stage driving circuit means for producing low frequency timing signals from said high frequency time standard signal, a digital display device driven by said timing signals, at least one time correcting switch, a safety switch, and control electronic circuit means interconnecting said time correcting switch and said frequency divider means and adapted so as to be disposed, in response to said safety switch, in either a first mode in which the correcting switch is isolated from said frequency divider means or a second mode in which the count in said frequency divider means may be selectively corrected by operation of said correcting switch.
Accordingly, an object of the invention is to provide a safety device for preventing erroneous operation of time correcting switches for digital electronic wrist watches having liquid crystal displays.
Still another object of the invention is to provide a digital electronic wrist watch having time correcting switches wherein the normal operation of the digital display is unaffected by said time correcting switches.
Still other objects and advantages of the invention will in part be obvious and will in part be apparent from the specification and drawings.
The invention accordingly comprises the features of construction, combinations of elements, and arrangement of parts which will be exemplified in the constructions hereinafter set forth, and the scope of the invention will be indicated in the claims.
BRIEF DESCRIPTION OF THE DRAWINGS For a fuller understanding of the invention, reference is bad to the following description taken in connection with the accompanying drawings, in which:
FIG. 1 is a block diagram of a conventional digital electronic wrist watch;
FIG. 2 is a top plan view of the exterior of a digital electronic wrist watch in accordance with FIG. 1;
FIGS. 3 and 4 are circuit diagrams depicting prior art connection arrangements for time correcting switches",
FIG. 5 is a partial block diagram of still another embodiment of a digital electronic wrist watch incorporating a safety switch and time correcting switches;
FIG. 6 is a partial block diagram of a digital electronic wrist watch incorporating a time correcting arrangement in accordance with the invention;
2 FIG. 7 is a block diagram of the control circuit of FIG. 6 in accordance with the invention; and
FIG. 8 is a circuit diagram of the control circuit of FIG. 7.
DESCRIPTION OF THE PREFERRED EMBODIMENTS Referring now to FIG. 1, a typical digital electronic wrist watch is depicted. The watch includes a quartz crystal oscillator X for providing a high frequency time standard signal. This high frequency time standard signal is divided by a multi-stage divider circuit 1 which divides the high frequency time standard signal into a 64 Hz signal. Power for divider circuit 1 is obtained from a silver battery 2 of 1.5 volts. The 64 Hz signal is further divided in hour, minute and second divider circuit stages 3 which produces time keeping signals for driving a digital display 5, which may be of the liquid crystal type. Divider circuits 1 and 3 are preferably formed from C-MOS elements as depicted in US. Pat. No. 3,717,990, issued on Feb. 22, 1973, so as to draw a minimum amount of power. The voltage of battery 2 is boosted by a power source circuit 4 so as to provide driving current for the digital display. Time correcting switches 6 are connected to the hour, minute and sec ond driving circuit stages respectively for the selective correction of each of said stages. Such correction, for example, can take the form of the indexing of each of the divider stages by one count for each manual operation of a time correcting switch 6. A safety switch 7 is connected between time correcting switches 6 and ground so as to prevent the unintended actuation of one of time correcting switches 6 when the watch is worn on the wrist of a user.
FIG. 2 depicts the outer case of a digital electronic watch incorporating the circuit of FIG. 1, the liquid crystal display 5, the three-time correcting switches 6 for the respective correction of hour, minute and second, and the safety switch 7 being depicted. The interconnection between time correcting switches and the divider stages has taken a number of forms, two of which are depicted in FIGS. 3 and 4. In FIG. 3, the time correcting switch 8 is an on and off-type switch, the circuit being adapted so that time is not corrected when the switch is off or open. When it is desired to correct the switch, the switch is closed and a signal is applied to the circuit to produce an output for correcting the associated divider stage. However, current flows from the boosted power source through a resistor when switch 8 is switched on so that the resistance of the resistor must be more than several'tens meg-ohms in order to minimize power consumption. A resistor of this magnitude requires either the application of special techniques for integration using C-MOS transistors or the provision of a separate resistor which is, because of its high value, relatively difficult to manufacture. Where a change-over microswitch such as switch 9 of FIG. 4 is utilized, the problem of power consumption can be dealt with only by mechanically increasing the change-over speed of the microswitch.
Generally, the circuit arrangement as depicted in FIG. 5 has been utilized, employing microswitches for time correction. In the embodiment of FIG. 5, switch 11 is a safety switch. When the moving contact of said switch is connected to the negative voltage side as shown in FIG. 5, an electric signal is applied to the corresponding divider stage for time correction by operating the corresponding time correcting switch 10.
and-time will not be properly displayed. Thus, it has been found that in an electronic wrist watch, the reliability of the electronic circuitry is greatly enhanced if the number of interconnections between mechanical contacts and the like and the electronic circuitry is minimized.
The foregoing difficulties are overcome by the circuit of FIG. 6 in accordance with the invention wherein a control circuit 12 is positioned intermediate the time correcting switches 10 and the hour, minute and sec- ,ond driver circuit stages. The safety switch 11 is connected so as to control the operation of control circuit 12 through the selective connection to either a negative voltage or ground.
The control circuit 12 is depicted in block diagram form in FIG. 7 and in circuit diagram form in FIG. 8, wherein a control circuit being formed of C-MOS components is depicted. As is seen in said figures, when safety switch llis connected to ground, representing an off state of the control signal of control circuit 12, the outputs of said control circuit are maintained at zero electric potential regardless of the state of the input signal. In this manner, the hour, minute and second driver circuits are isolated from the noise-generating potential of the correcting switch 10 so that said switches cannot affect the reliability of the circuit. The only potential for noise generation is in the safety switch, which is a substantial reduction in potential as compared with the prior art arrangements where all of the switches were potential sources of noise. When the safety switch is connected to the negative potential, the outputs of the control circuit correspond to the inputs, and therefore to the state of the correcting switches.
Further, in general, the safety switch differs in construction from the correcting switches, and generally causes little difficulty in operation. Generally, the safety switch is designed so that it is pulled out only at the time of correction and pushed into its initial position after time correction. This structure generally insures that the safety switch is never in the extended position when the watch is being worn. While the number of connections between mechanical switches and the electronic circuit is increased during time correction, this has a negligible effect on the operation of the watch due to the short period of time occupied by such time correction.
Accordingly, the arrangement in accordance with the invention serves both to provide a safety switch for preventing erroneous operation of the time correcting switches, and further, to increase the reliability of the entire watch through avoiding mis-operation due to noise caused by the switches.
It will thus be seen that the objects set forth above, and those made apparent from the preceding description, are efficiently attained and, since certain changes may be made in the above constructions without departing from the spirit and scope of the invention, it is 4 intended that all matter contained in the above description or shown in the accompanying drawings shall be interpreted as illustrative and not in a limiting sense.
It is also to be understood that the following claims are intended to cover all of the generic and specific features of the invention herein described, and all statements of the scope of the invention which, as a matter of language, might be said to fall therebetween.
What is claimed is:
1. An electronic timepiece comprising oscillator circuit means for producing a high frequency time standard signal; frequency divider means for dividing said high frequency time standard signal to produce a plurality of low frequency timekeeping signals; display means for the digital display of time including a display element associated with each said timekeeping signal to be displayed; electronic control circuit means coupled to said divider means; means for providing a correction signal directly coupled to said control circuit means; at least one manually operable time correction switch, each said correction switch being associated with a displayed timekeeping signal to be corrected, each time correction switch being directly coupled to said control circuit means for the selective application of said correction signal through said control circuit means to the divider means for the selective correction of the count of the associated displayed timekeeping signal to be corrected upon the manual actuation of said correction switch; and a manually operable multi-position safety switch directly coupled to said control circuit means, said control circuit means isolating each correction switch from said divider means to prevent selective application of a correction signal by actuation of any of said correction switches when said safety switch is in a first position, and said control circuit means effecting a transmission of a correction signal through said control circuit means and to the divider means in response to actuations of each of said correction switches for effecting time correction of the displayed timekeeping signal associated with the actuated correction switch when said safety switch is in a second position whereby the time standard signal applied by the oscillator means to said divider means to provide timekeeping signals to be displayed is not interrupted during the selective application of said correction signal by each correction switch to the divider means.
2. An electronic timepiece as claimed in claim 1,
.wherein said divider means timekeeping signals to be displayed are seconds, minutes, and hours timekeeping signals, and three manually operable time correction switches are provided, one of said time correction switches being associated with each of said seconds, minutes and hours timekeeping signals for the selective correction thereof.
3. An electronic watch as recited in claim 1, wherein said divider circuit means is formed from C-MOS components.
4. An electronic watch as recited in claim 1, wherein said control circuit means is a gate circuit formed from C-MOS components. I
5. An, electronic watch as recited in claim 1, wherein said digital display means is a liquid crystal display.