GB2103846A

GB2103846A - A digital timepiece

Info

Publication number: GB2103846A
Application number: GB08123027A
Authority: GB
Inventors: Christopher Carr Laughton
Original assignee: Individual
Current assignee: Individual
Priority date: 1981-07-25
Filing date: 1981-07-25
Publication date: 1983-02-23

Abstract

A digital timepiece is disclosed in which a display area or screen (11) is separated into three zones (12, 13, 14) one of which (13) is located between the other two in a row. Minutes are displayed in the left hand zone (12) and hours in the right hand zone (14), whilst the intermediate zone displays an indication of whether the minutes are "past" the hour or "to" the hour. The display in the minutes zone (12) increments from zero to twentynine and then decrements from twentynine to zero, with a subsidiary or alternative display area (15, 17) displaying "half past" the hour for the duration of the interval for which the numeral 30 would be displayed by the minutes display: the quarter hours are similarly represented, whilst the numerals 12a and 12b of the minutes display are suppressed. <IMAGE>

Description

SPECIFICATION A digital timepiece The present invention relates to a digital timepiece. Such timepieces have become very popular because of their considerable accuracy and great reliability. Indeed, digital timepieces employing iiquid crystal displays are entirely electronic and have no moving parts whatsoever.

They are, therefore, both reliable and durable, and the accuracy, as mentioned above is very much greater than anything obtainable mechanically.

Digital timepieces are also easier to read than analogue timepieces in that they set out numerically the time in a display indicating hours and minutes, whereas it is necessary to interpret the reading of an analogue timepiece where the indicating pointers or hands are usually located between adjacent indicia representing the time as it is to be expressed.

However, it is usual for the display sections of a digital timepiece to be set out in a sequence where the hours are represented by the first two digits, the minutes by the second two digits and the seconds, if such are provided, by a third pair of digits. This is a logical consequence of the use of digital counters, encoders and displays since the time displayed is determined by dividing down from a high frequency signal generated by a crystal oscillator operating with great accuracy.

Aithough this is logically consistent in that the longest units of time appear in the position where they would be read first (it being assumed that reading of the display takes place conventionally from left to right) the intermediate units are in the centre and the shortest units are in the position where they are read last. On the other hand, because of the long history of indicating time by analog timepieces an idiosyncratic and to some extent stylised manner of expressing the time has evolved. In this, as is widely known, the intermediate time units (that is the minutes) are expressed first and the longer time units, the hours, are expressed last.If the shorter time units, the seconds, are expressed then they too are referred to before the hour units: moreover, the first half of a time division between successive hours is expressed in terms of the number of minutes which have elapsed since this hour, whilst the second half is expressed in terms of minutes left to run before the next hour. In contradistinction a digital timepiece can only indicate the number of minutes which have elapsed since the last hour unit, and although it is perfectly correct and comprehensible to express time in this way, the majority of people nevertheless convert a time displayed as greater than thirty minutes past a given hour into the number of minutes left to run before the next succeeding hour.This can lead to errors and confusion since it requires a mental calculation to be performed after the timepiece has been read and before the time is expressed either by way of verbal communication or even as a mental note.

In addition to this, the quarter hours are almost invariably expressed as a fraction of an hour and not in terms of the number of minutes, and digital timepieces do not give any special prominence to the quarter or half hours. Thus, digital timepieces, although entirely correct in their presentation are to some extent, and for some purposes, rather too detailed in that they display too much information for many purposes. In particular, the display of seconds is continually changing in a manner which cannot be ignored as readily as the "seconds" pointer of an analogue timepiece because of the discrete nature of the commutations from one number to another. In an analogue timepiece the "seconds" pointer moves smoothly and continuously, and therefore does not constitute such a noticeable or significant display as the "seconds" section of a digital display.

The technical problem on which the present invention is based is thus that of providing a digital timepiece having a display set out in a manner such that it can be read in the same way as time is conventionally expressed, that is with the "minutes" occuring first and the "hours" occurring last and with, preferably, a separate and more prominent significance being given to the quarter and half hours.

This is achieved, in accordance with one aspect of the present invention, by a digital timepiece having a display with a part which increments continuously in one direction through a predetermined cycle and a part which increments up to a predetermined number and then decrements down to zero in a continuously alternating cycle. The first part of the display, continuously incrementing in one direction through a predetermined cycle thus represents the hours, and the digital display for this section would run from 1 to 12 (there being no zero in the conventional expression of diurnal time).

According to another aspect ot the present invention the technical problem is resolved by a digital timepiece in which the display includes a part which indicates the division of time in hours and a part of which indicates whether the display is in the first half or the second half of a time division between successive hours. This permits the display to represent the time as it is expressed, with the hour change actually taking place on the half hour, that is as the minutes display changes from 30 minutes past the hour (except, of course, for timepieces intended for use in countries such as Germany where the hour change takes place as the minutes display changes to the "30 minutes past" representation, since the expression of time in German differs slightly from that in English-speaking countries).

This latter part of the display may alternatively indicate the words "past" and "to" in the first and second half of the hourly time division respectively. The display may be provided by a socalled "secret" display in which the two words are located in different positions on a display screen and illuminated during the appropriate periods, the display of the non-illuminated word being sufficiently obscure to provide no confusion.

Alternatively, particularly if a liquid crystal display is used, the words may be set up by suitable combinations of a conventional seven segment display of the type conventionally used for representing numerals since the letters involved can all be generated with reasonable similarity by the seven segment display.

According to a third aspect of the present invention a digital timepiece has a display which comprises three sections in a row, the first section at one end of the row displaying minutes, the second, at the other end of the row, displaying hours, and a third section, between the first and second sections, indicating whether the first display section represents the first half of the second half of a time division between successive hours displayed by the said second display. In order to provide a display which can be read in a conventional manner similar to that used for analogue timpieces, the said first part of the display preferably counts alternately up to thirty minutes and down to zero, the reverse direction count commencing concurrently with commutation between successive hours displayed by the said second section of the display.

The timepiece may also include means for displaying the elapsed seconds during the currency of a digital display of any one minute, and such a display of elapsed seconds may be an analogue display or a digital display although, in order to make it easier to ignore the seconds display when they are not required, this is preferably in an analogue form. Whatever the form of the "seconds" part of the display they may be linked to a control by means of which this display can be suppressed if it is not wanted.

There may be further provided a display section which represents the quarter and half hour points and which, in operation, supersedes or replaces the display of minutes for the time interval lasting for one minute from the respective quarter or half hour point.

A timepiece constructed in accordance with the principles of the present invention will be extremely easy to read, enabling a person to express the time indicated by a digital timepiece in the conventional manner. This would have the dual advantage of avoiding the possibility of misreading an analogue clock (which all too frequently happens, particularly in the case of people who have frequently to read and express the time, such as broadcasters and who, because of the nature of their position, and of the circumstances in which the broadcast is made, are relied upon to get the time right) and at the same time obtained digital accuracy in the timepiece display.

One embodiment of the present invention will now be more particularly described, by way of example, with reference to the accompanying drawings, in which: Figure 1 is a face view of a digital display illustrating one way in which the invention may bc put into effect; Figure 2 illustrates the manner in which a seven segment display may be adapted to provide an indication suitable for a part of the display of Figure 1; Figure 3 is a schematic view of a modification of the display of Figure 1; and Figure 4 is a block schematic diagram illustrating a circuit suitable for driving the display of Figure 1.

Referring now to the drawings the display illustrated in Figure 1 comprises a generally rectangular display face 11 separated into three main display sections or areas generally indicated, 12, 13 and 14 in a row reading from left to right.

The first display area 12 is further separated into two separate regions 1 2a, 1 2b in each of which can be displayed one numerical digit from 0 to 9 although in fact only the digits 1, 2 and 3 are ever displayed in the area 1 2a as will be explained below.

The right hand display section 14 is identical with the left hand display section 12 and, like the section 12, is separated into two equal areas 1 4a, 1 4b each of which has means for displaying a single numerical digit. For a twelve hour clock the left hand area 1 4a requires only to display the digit 1 whilst the right hand area 1 4b displays digits 0--9 as appropriate. The digit zero could be displayed in the left hand area 1 4a when the right hand area 1 4b display digits 1 to 9 but it is preferable that no display is illuminated in the left hand area 1 4a in these circumstances to avoid presenting superfluous information in that the first decade is conventionally referred to by the number alone and not by 01, 02 etc.

The central section 1 3 is horizontally divided into three regions 1 3a, 1 3b and 1 The upper area 1 3a displays the word "minutes" permanently whilst the timepiece is in operation, whilst the areas 1 3b, 1 3c respectively display the words "past" and "to" alternatively, the latter whilst the display 12 is displaying digits between 30 and zero on a decrementing count immediately after the display 14 has commutated to a new digit, and the former whilst the display 12 increments from zero up to 30 leading to the next commutation of digit in the display 14. As illustrated the display on the timepiece in Figure 1 represents 23 minutes past 6.

Immediately to the left of the display section 1 2 is a subsidiary display section 1 5 horizontally separated into upper and lower areas 1 Sa, 1 Sb the former of which displays the digit 1 and the latter of which contains a seven segment display set to represent two or four as appropriate. These displays 1 Sa, 1 Sb are energised when the display 12 reaches 15 or 30 at which time the display 12 is extinguished and the display 1 5 illuminated for the whole minute beginning with the commutation of the display 12 to the number 15 or the number 30 and terminating with its next commutation either up to 16 or down to 14 in the case of the 4, or down to 29 (from 30) in the case of the 2.

Finally, beneath the display area generally indicated by the outline 11, and having the same horizontal extent thereas, is a subsidiary display 1 6 separated into 60 illuminable areas which are sequentially illuminated at regular intervals for example at one second intervals throughout the whole of each minute so that the proportion of an elapsed minute can be read analogically by reference to the position of the illuminated segment at any time along the display area 16.

Alternatively the illuminable areas may be illuminated in the manner of a bar graph so that the proportion of illuminated areas represents the proportion of a minute unit elapsed.

In the embodiment of Figure 1 the display areas 1 3b, 1 3c are permanent "screen" signs which are alternatively illuminated in order to display the "past" or "to" symbols. In an alternative embodiment outlined in Figure 2 this could be achieved by means of four seven segment display units programmed to display "past" or "to" when suitably energised. This allows the same area to display the two alternative symbols.

In the modified arrangement of Figure 3, instead of having a completely separate area 1 5 for displaying the quarter hour or half hour symbol a subsidiary region 17 is located above the display area 1 2b and there is no area corresponding to the display area 15a or 1 sub. On the quarter hours the display area 1 7 is illuminated with a digit 1 and a horizontal line separating the display area 17 from the display area 1 2b is illuminated whilst the display illuminated in the area 12a,12b changes from 15 to read 4 in the area 1 2b whilst the area 1 2a is extinguished entirely at "quarter to" and "quarter past" each hour.As can be seen in Figure 3 the time displayed then represents quarter past or a quarter to the hour. A similar arrangement is effected when the count reaches 30 to display half past the hour. Again, the display is simply read from left to right in the conventional manner: in Figure 3 the display is shown representing a quarter to eight.

Turning now to Figure 4 the circuit illustrated comprises a crystal oscillator 20 the output of which is fed to a divider circuit 21 which divides the crystal frequency down to a pulse repetition frequency of 1 per second. This is fed to a counter 22 having a parallel output to the display 16, that is the "seconds" display of Figure 1. The counter 22 counts up to 60 and then resets to zero and the reset pulse, which occurs therefore at each minute, is used as the input signal to the "minutes" section of the timepiece. This comprises two and gates 23, 24 the outputs of which are fed to respective counters 25, 26. The counter 25 is set to count up from 0 to 30 and includes a parallel coded output to the display section 12 to provide the instantaneous digital readout.When the counter 25 has reached 30 it produces a reset pulse setting itself to zero. The reset pulse is also fed to three other circuits, namely the AND gate 24, as the second input thereto, a counter 27 and a coder 28 for the display 15.

When the AND gate 24 receives the reset signal from the counter 30 it then allows the "minutes" pulses arriving from the counter 22 to pass thus putting the down counter 26 into operation. This removes the reset output from the down counter 26 so that the AND gate 23 which previously fed the pulses from the counter 22 to the counter 25 is now closed. The display 12 is now fed from the down counter 26 which also incorporates a coder so that the display 12 is supplied with the digital information to decrement from 30 down to zero. When it reaches zero the down counter 26 produces a reset pulse resetting itself to 30 and enabling gate 23 to pass pulses to the up counter 25 which thus disables the gate 24 turning off the counter 26 and leaving it in its reloaded state ready to count down from 30 as before.The counter 27, which receives an input pulse each time the reset output from the up counter 25 occurs, thus counts the hours and this counter incorporates a coder for supplying the display 14 of Figure 1. By supplying the counter 27 from the reset input of the up counter 25 commutation of the hours takes place at a point halfway between two consecutive hours. In fact, a suitable delay of one minute is introduced so that the timepiece shows the preceding hour until 31 minutes past this hour, at which point it commutes to indicate 29 minutes to the next hour. In fact, the number 30 is never actually displayed by the "minutes" display 12 since the reset output from the counter 25 is passed to the coder 28 which energises the display 15 to represent half past the hour.At the same time the coder 28 generates a signal on line 29 which is fed to a quench input of the display 12 so that this display is quenched for the duration of the minute during which the "half" display 15 is energised.

Likewise both the counters 25 and 26 have intermediate outputs on lines 30 and 31 respectively, which are energised when the counters reach the number 1 5. These two lines 30, 31 are fed to a "quarter" code unit 32 which supplies the display 1 5 with the appropriate coded signal to display the quarter sign. The reset signals from the counters 25, 26 are also fed to respective bistable circuits 33, 34 the outputs of which are supplied to the "to" and "past" sections 1 3b, 1 3c respectively of the display 13.

The outputs of the bistable circuits 33, 34 are each fed to the reset input of the other circuit so that the "to" and "past" displays commute simultaneously.

Finally, the timepiece is provided with a display 35 indicating whether the "hour" display 14 represents time am or pm. This display 35 is fed from a bistable circuit 36 the input to which is supplied from an AND gate 37 having one input from the reset output of the counter 27 and another input from the reset input of the down counter 26 which ensures that although the "hour" counter 27 will commute from 11 to 12 half an hour before 12 o'clock, the AND gate 37 is not enabled until the end of the 30 minute down count at which time the reset impulse from the counter 26 is generated.

The circuit illustrated in Figure 4 and the display of Figures 1 to 3 may be incorporated in a digital clock or a digital watch as desired.

Claims (Filed on 26 July 1982) 1. A digital timepiece having a display which comprises three sections in a row, a first section at one end of the row displaying minutes, a second section, at the other end of the row, displaying hours, and a third section, between the first and second sections, indicating whether the first display represents the first half or the second half of a time division between successive hours displayed by the said second display.

2. A digital timepiece as claimed in Claim 1, in which the said first part of the display counts alternately up to thirty minutes and down to zero, the reverse direction count commencing concurrently with commutation between successive hours displayed by the said second section.

3. A digital timepiece as claimed in Claim 1 or Claim 2, in which the display further includes means for displaying the elapsed seconds during the currency of a digital display of one minute.

4. A digital timepiece as claimed in Claim 3, in which the display of elapsed seconds is an analogue display.

5. A digital timepiece as claimed in Claim 3, in which the display of elapsed seconds is a digital display.

6. A digital timepiece as claimed in Claim 4 or Claim 5 further including means for selectively suppressing or extinguishing the said display or elapsed seconds.

7. A digital timepiece as claimed in any preceding Claim, in which there is further provided a display which represents the quarter and half hour points and which supersede or replace the display or minutes for the time interval lasting for one minute from the quarter or half hour point.

8. A digital timepiece as claimed in any preceding Claim, in which the third display section comprises a conventional seven-segment array programmed to display the words PAST or TO.

9. A digital timepiece as claimed in any preceding Claim in which electrical signals for generating the said displays are provided by frequency division of an oscillator and subsequent counting of the frequency divided oscillations.

10. A digital timepiece as claimed in Claim 9, in which the "minutes" display is generated by two counters, one counting up from zero to thirty and the other counting down from thirty to zero, means being provided for enabling the said two counters sequentially and alternately, the commencement of counting by each being triggered by the compietion of counting by the other.

11. A digital timepiece having a display with a part which increments continuously in one direction through a predetermined cycle and a part which increments up to a predetermined number and then decrements down to zero in a continuous alternating cycle.

12. A digital timepiece in which the display includes a part which indicates the division of time in hours, and a part which indicates whether the display is in the first half or the second half of a time division between successive hours.

1 3. A digital timepiece substantially as hereinbefore described with reference to the accompanying drawings.

**WARNING** end of DESC field may overlap start of CLMS **.

Claims

**WARNING** start of CLMS field may overlap end of DESC **. half an hour before 12 o'clock, the AND gate 37 is not enabled until the end of the 30 minute down count at which time the reset impulse from the counter 26 is generated. The circuit illustrated in Figure 4 and the display of Figures 1 to 3 may be incorporated in a digital clock or a digital watch as desired. Claims (Filed on 26 July 1982)

1. A digital timepiece having a display which comprises three sections in a row, a first section at one end of the row displaying minutes, a second section, at the other end of the row, displaying hours, and a third section, between the first and second sections, indicating whether the first display represents the first half or the second half of a time division between successive hours displayed by the said second display.