DE2362970B2 - ELECTRONIC CLOCK - Google Patents

Description

The reference relates to an electronic clock with a battery, a single line source, a logic circuit, a control circuit and a display device which has several segments and displays at least sulfides and minutes, the hour and minute display with a control frequency of at least JOIIz can be controlled alternately.

The last few years have gone through great With advances in the field of electronics the electronic clocks have always evolved and have become more and more widespread. Instead of the usual analog display, the frame appears of this development the digital display by means of an electrical digital line display element. With these Electronic clocks containing plague body components are used as a source of energy from a battery Capacity is limited because the battery is housed in the limited space of a wrist watch must become. The display element has the largest share in the total energy consumption. There is therefore that Need to reduce this percentage.

With the common display of hours, minutes and seconds that has been common up to now, one is relative high amperage is required due to the voltage drop caused by the internal resistance of the Baiterie often results in incorrect operation of the circuit or the display element.

From the DT-OS 19 37 868 is an electronic clock known with a liquid crystal device, with the revolving for the hours, minutes and seconds counters Pointer are simulated in order to imitate the pointer display common in conventional clocks. Included segments of an inner ring can be used to display the hours and segments of an outer ring to display the minutes be used. The effort for the sequence logic can be kept particularly small if that is the case segment used for the hour display and the segment currently used for the minute display are alternately excited. To emulate a pointer display, these two segments are alternated excited at a frequency above the flicker frequency that can still be perceived by the human eye is, for which a control with more than 30 pulses per second is considered necessary will.

The FR-PS 21 05 003 deals with the control of several digitally displaying satellite clocks by one Clock. The number of connecting wires between each satellite clock and the mother clock To keep it low, the individual digits of the, for example, mn l.ichl emulating diodes are built up Display the digital display one after the other. In order to simulate a viewing display, is also used with this known display device continuously repeats the control mn a frequency that is above the temporal resolution of the human eye.

If this method, in which the various digits are sequentially controlled in a pulse-free manner, would be used for an electronic wristwatch with a digital display having light-emitting diodes in order to reduce the load on the small batteries used in wristwatches, the following disadvantage would arise. Because of the limited maximum current of such a small battery, ie because of its relatively high internal resistance, the number of LIiD (light-emitting diode) segments that light up at the same time affects their luminosity. This means that the current available per illuminated individual segment depends on the number of simultaneously illuminated segments. If, for example, the I and then the 8 are activated in a pulse-like manner * 5 in a display using the usual 7-segment digits to show an 18, the 8 appears less bright than the I. However, such an unevenly bright time display is perceived as annoying.

The object of the present invention is therefore

to make an electronic clock with LED display available, which in the event of measures to extend the The service life of a small watch battery with a limited maximum sirom is uniformly bright Display of all LED segments made to light up for a current time display made possible.

This object is achieved according to the invention.

that of the several LED segments per digit only one segment is controlled sequentially.

With this measure, the battery needs constant

only ever to supply power for a single LED segment, so that the battery load is always even and thereby the brightness of all the segments that are lit up is the same.

The invention is explained in more detail by means of exemplary embodiments with the aid of five figures. It shows Fig. I is a block diagram of a clock with digital time display,

F i g. 2 that of the in F i g. 1 clock control device shown generated digit signals,

F i g. 3 is a block diagram of a clock in which the time is displayed by means of segments;

F i g. 4 that of the in F i g. 3 clock control device supplied signals,

Fig. 5 shows the signals for the hours, minutes and Second units of the embodiment according to FIG. 3.

example 1

The electronic clock shown in Fig. 1 contains a normal signal generator A, a logic circuit B, a control circuit C and a display device D. A time display in hours, minutes and seconds is provided. For this purpose, the display device contains six digits of seven-segment display elements which are constructed from gallium-arsenide-phosphide light-emitting diodes. The time display in six digits is effected in such a way that six-digit signals (their pulse width in the present case is ₁ /2% seconds) corresponding to the six digits are given by the eight shown in FIG

encoded signals which are sent by the circuit be delivered so that the display / iller after /.iffer he follows. Ak I olgc of this is self-contained in this Λη / the l.cislungs ·. he only needs half the size or still smaller than with a display event in which at the same time all digits / lights are brought

Example ζ

In the case of I '1 g. 3 illustrated electronic I her. in which the time is displayed by means of digits consisting of seven semen each, the clock control device yefen seven types of segment code signals .7 and six types of digit code signals b. that is, 13 types of coded signals included in Γ ι g. 4 are shown. The pulses of the segment code signals and the digit code signals are supplied by the divider B and have a repetition rate / of 2 048 Hen / or 256 Hen /. In a number / decoding device, I-second signals supplied by the divider are counted and converted into signals for digits consisting of seven segments, which are used for the display of seconds. Serving minutes and hours. The signals obtained are modulated by the segment signals (F 1 g. 4a) and the target signals (F i g. 4h) _{supplied for 2} s from the timing device, and it is possible to choose the pulse width of the working phase so that they equal to or less than ^[ .U? is. In this case, each segment of the display device can be put into the lighting state at a different time from the other segments.

In this way, an electronic clock is obtained in which the maximum number of segments that can be illuminated at any given moment is one and therefore the energy required for compared to the usual method in which all the digits are moved to the illuminated country at the same time the display only V ₁ to V ₄ . If the display frequency is set to 32 lenz or more, then uJl
Obtain a flicker-free clear time display due to the sluggishness of the human eye. Thus, an electronic timepiece with excellent operating properties which can be operated at a low temperature can be obtained, which enables accurate display.

Example i

In the known digital time display, hours. Minu'en and six seconds Digits and four digits to indicate hours and minutes. If you want to read the time, so you can not aiii the total display in the cone take a look and it is difficult to read them.

In order to avoid this disadvantage, it is provided according to a development of the invention that the Display units for the hours, for the minutes and for the seconds not simultaneously, but one after the other can be controlled. With this display method, if the time delay is / one "i" second or more, then the display units light up one after the other and you get a clear and easy-to-read time display. With this type of time display, the Energy consumption also reduced. It can be reduced even further if the examples 1 and 2 described measures are provided.

As already mentioned, the invention is the The sluggishness of the human eye is exploited, i.e. the ability of the eye to reproduce an image impression and the current-light emission characteristics of light emitting · diodes, so that an electronic Clock is obtained whose energy consumption is reduced compared to known electronic clocks and the display of which is clear and which is made using integrated circuit technology can be set up easily.

For this purpose 2 sheets of drawings

Claims (1)

Claim: Electronic clock with a battery, a time normal. a logic sound, an Mottled circuit and one having several segments and at least hours and minutes indicating display device, the hours and the miniature display with a viewing frequency / of at least 30 II / alternately controllable are, d u r c h g e k e η η /. e i c h η e ι. that at a numeric display with several LED segments per digit only one segment sequentially will be kissed.