GB1595621A

GB1595621A - Displaying measuring instrument

Info

Publication number: GB1595621A
Application number: GB2764/78A
Authority: GB
Original assignee: Zube F W
Current assignee: Zube F W
Priority date: 1977-01-25
Filing date: 1978-01-24
Publication date: 1981-08-12
Also published as: IT7819567A0; NO780174L; CA1102023A; JPS53106067A; IT1092099B; DE2802684C2; NL171292C; JPS58145510U; FR2378262A1; NL7700758A; BE863288A; SU1009289A3; NL171292B; DE2802684A1; FR2378262B1

Description

(54) DISPLAYING MEASURING INSTRUMENT (71) We, THIAM LING GO, of 483 Generaal Spoorlaan, Rijswijk (ZH) Netherlands, and FRIEDIRICS VILHILM ZUBE, of Midda, Federal Republic of Germany, a Dutch Subject and a Germain Citizen respectively, do hereby declare the invention, for which we pray that a patent may be granted to us, and the method by which it is to be performed, to be particularly described in and by the following statement: ABSTRACT.

A measuring instrument with a combined digital and analogue display is described, the least significant digit of the measured value to be displayed is indicated by means of a linear scale composed of scale division units and multiples thereof. The division which corresponds to the instantaneous value of the measureand has a different visual appearance from the surroundings thus indicating the instantaneous value of the least significant digit.

The higher order digits are displayed by numeral indicators located at the lower end of the linear scale. Thus, the display of the highest order digits is digital, whereas the display of the lowest order digit is both digital (by the particular scale mark concerned) and analogue (by the location along the scale of that particular scale mark).

DISPLAYING MEASURING INSTRUMENT.

The invention relates to a displaying measuring instrument with a digital measuring circuit for the magnitude to be displayed, in which the display of the value of that magnitude is obtained by selective change of appearance of certain visual display elements of a display panel.

Traditionally, measuring instruments have for a long time been designed as pointer instruments. In such instruments, the magnitude to be measured is applied to a drive means such as a moving coil, which positions the pointer along a calibrated scale in correspondence with the value of the quantity to be measured. Such pointer instruments have the advantage that an aproximate impression of the measuring value can be obtained at a glance, and that any change with time of the measuring value can be followed easily. In case of the occurrence of rapid fluctuations of the measuring value too, a good indication of the mean value can be obtained and, provided that the fluctuations are not too fast in comparison to the inertia of the measuring instrument, it is also possible to obtain a rough impression of the presence and magnitude of such fluctuations. A further advantage is the absence of active components in as far as no extreme sensitivity is required. However, disadvantages are the sensitivity for mechanical defects, the small accuracy of the measuring instrument itself, the need for a very careful reading, in which it is always necessary to make an estimate of the precise position of the pointer with respect to the scale, and the very limited possibility of reading fluctuations of the measuring value.

Later, measuring instruments with digital read-out have been developed, in which the value of the measuring quantity is displayed directly in numerals. Advantages thereof are that the accuracy of the measuring instrument can be increased almost indefinitely, that no estimate is necessary for reading the measuring instrument, that the measuring instrument is comparatively insensitive to mechani can defects and that by a combination of standard units, any desired measuring function and measuring range can be obtained. Also, it is possible without difficulties, to obtain an indication of the polarity of the measuring quantity and of any exceeding of the range.

However, disadvantages are that the reading becomes virtually impossible for rapidly fluctuating measuring values, since one or more display numerals will change rapidly in that case, whereby these numerals can be read hardly or not at all. Also, it is difficult to obtain an impression of the course of a slowly changing measuring value, since the speed with which and the direction in which the measuring value changes, can be derived only from the time which passes between the changes of the displayed numerals and the sense in which these numerals change res pectively. For fluctuating measuring values it is virtually impossible, to read the range within which the measuring value fluctuates.

Because of these advantages and disadvantages, both kinds of measuring instruments found an application area of their own. Since the circumstances in which a measuring instrument will be used cannot always be predicted with any certainty, measuring instruments of either type are often used in cir cumstances in which the disadvantages inherent to the type of measuring instrument concerned are of great practical importance.

The invention aims at providing a measuring instrument which to a large extent com bines the advantages of both types of measuring instruments referred to, and also to a large extent lacks the disadvantage of both types of measuring instruments referred to.

According to the present invention there is provided an instrument display comprising an analogue scale having a basic unit of divi sion and multiples thereof, a plurality of numeral indicators located parallel to said analogue scale, each of said numeral indicators being physically connected to a multiple unit of said analogue scale so that as a measured parameter equals or exceeds an analogue scale multiple value, the numeral indicator con nected thereto changes state to visually indi cate a more significant digit related to said multiple value, a less significant digit being indicated on said analogue scale.

Visual display elements correspond to the scale divisions of the calibrated scale, which is conventional for a pointer instrument, and they can emit light upon energization, e.g. by means of light emitting diodes, gas discharge lamps or incandescent lamps, or they can change their reflection coefficient or transmission coefficient upon energization, e.g. by means of liquid crystals. The measuring instrument can be designed in such a way that for each measuring value, only a single display element, corresponding to that measuring value, displays a deviant appearance (point scale, in which the display element with deviant appearance corresponds to the tip of a pointer) or can be made in such a way that all display elements relating to values below the instantaneous measuring value have a first appearance, and all display elements belonging to values above the instantaneous measuring value have a second appearance (rod scale, corresponding to the presentation obtained by a mercury thermometer) The numerals of higher order of the measuring value, for which the disadvantages of digital measuring instru ments are less important, as well as an indi cation for the polarity andlor exceeding of the range, can be displayed conveniently in the way which is usual for digital measuring instruments. The symbols used for that purpose are preferably arranged adjacent the low end of the scale constituted by the visual display elements of the row. An instrument display according to the invention is eminently suited for providing a limit value of a signal by using one or more movable tabs which can be displaced along the row of visual display elements, carrying light sensitive elements which respond to the changes in the appearance of the display elements.

The invention is further elucidated below with reference to the drawing, which shows a front view of the display panel of a measuring instrument according to the invention.

The analogue scale of the instrument visual display comprises a row of display elements 1, the appearance of which depends upon the electric control. The display elements 1 can e.g. operate with light emitting diodes, gas discharge lamps or incandescent lamps, in which case they light up upon electric energization, or they can consist of liquid crystals, the optical transmission coefficient or reflection coefficient of which changes dependent upon the electric control, in which case they visually deviate from the surrounding. By way of example, it is here assumed that the display elements 1 operate with light emitting diodes.

Each fifth display element 2 has a greater length than the remaining display elements 1, for marking multiples of five. For the remainder, the display elements 2 operate in the same way as the display elements 1. Each tenth display element 3 not only is longer than ;the display elements 1, for marking multiples of ten, but also cooperates with its own numeral indicator 4 which makes visible the sequential number of the multiple of ten concerned. For the remainder, the display elements 3 operate in the same way as the display elements 1 and 2.

To the left of the scale constituted by the display elements 1, 2 and 3, which towards the right shows increasing numbers, a numeral indicator 5 is arranged, which by way of example has been shown as a numeral indicator for numerals made up of seven segments. This numeral indicator 5 also contains a decimal point 11 to the right of the numeral segments, a minus sign to the left of the numeral segments, and a range overload indication above it. The seven numeral segments, the decimal point, the minus sign, and the range overload indication can be illuminated by light emitting diodes, gas discharge lamps, incandescent lamps of liquid crystals. If desired, several numeral indicators 5 can be arranged side by side, for indicating more than one numeral.

In the shown embodiment it has beel; assumed that the instantaneous measuring value equals 3.42, that the polarity is positive, and that no range overload has occurred. Con sequently, the illuminated numeral segments 10 have an appearance deviating from the surrounding, indicating the numeral 3 of the measuring value, the decimal point 11 has an appearance also deviating from the surround ing, which obviously indicates the decimal point, the mark 6 has an appearance deviating from the surrounding, indicating the numeral 4 of the measuring value, and the second display element 1 to the right of it has an appearance differing from the surrounding, indicating the numeral 2 of the measuring value.

If the measuring value slowly increases, the second display element 1 to the right of the mark 6 resumes its initial condition, not deviating from the surrounding, and in its place, the third element 1 to the right of the mark 6 assumes an appearance deviating from the surrounding etc. As soon as the measuring value reaches 3.50, the mark 6 resumes its initial condition, not deviating from the surrounding, and the mark 7 which indicates a 5, assumes an appearance differing from the surrounding. For a decreasing measuring value, this process occurs in the reverse sense.

The control of the numeral segments of the numeral indicator 5, and of the decimal point, the minus sign, and the range overload indicator thereof, occur in the conventional way.

In the above it has been assumed that at any time only a single display element 1, 2 or 3 has an appearance differing from the surrounding. The mark concerned thereby resembles the tip of the pointer of a pointer instrument. However, it can also be arranged that all display elements to the left or to the right of the display element indicating the instantaneous measuring value, also have an appearance differing from the surrounding. In that case, one obtains a presentation corresponding to the mercury column of a mercury thermometer, in which the transition between the display elements which do and do not deviate from the surrounding, indicates the measuring value.

A measuring instrument of the type described is a favourable combination of digital and analogue presentation. With the exception of the numeral of the lowest order of the instantaneous measuring value, all numerals of the measuring value are presented directly and digitally, so that they can be read at a glance. The numeral of the lowest order but one of the instantaneous measuring value is not only presented digitally, but also analog ously (since the location where that numeral is displayed depends upon the value of that numeral). The numeral of lowest order of the measuring value is displayed exclusively in an analogous way.

If the measuring value fluctuates, the display elements 1, 2 and 3 which deviate from the surrounding change correspondingly. Each of them therefore deviates from the surround ing only during part of the time, and the range within which the measuring value fluctuates can thereby be observed, with or without flicker, dependent upon the fluctuation fre quency. Because of the inertia-free presentation, this is true even for high fluctuation frequencies.

A measuring instrument of the type referred to is excellently suitable for signalling limit values. For that purpose, a rail or slot can be provided alongside the scale, along which two or more tabs 9 can move. Each of these tabs carries a light sensitive element (e.g. a photodiode) which provides a limit value signal as soon as the underlying display element 1, 2 or 3 assumes an appearance deviating from the surrounding. This can be done very easily if the display elements 1, 2 and 3 light up in that they are provided with light emitting diodes, gas discharge larnps or incandescent lamps, but is also possible if the display ele ments 1, 2 and 3 have an optical transmission coefficient or reflection coefficient dependent upon the control, such as when using liquid crystals, provided that sufficient ambient light is available, or a light source is available.

WHAT WE CLAIM IS:- 1. An instrument display comprising an analogue scale having a basic unit of division and multiples thereof, a plurality of numeral indicators located parallel to said analogue scale, each of the said numeral indicators being physically connected to a multiple unit of said analogue scale so that as a measured parameter equals or exceeds an anlogue scale multiple value, the numeral indicator connected thereto changes state to visually indicate a more significant digit related to said multiple value, a less significant digit being indicated on said analogue scale.

2. A display as claimed in Claim 1, wherein said analogue scale is a fine scale division and each numeral indicator is a coarse scale division.

3. A display as claimed in either Claim 1 or Claim 2, wherein said numeral indicator is illuminable.

4. A display as claimed in Claim 4, wherein each multiple division is substantially greater than each basic unit of division.

5. A display as claimed in any preceding claim, wherein at least one movable tab is locatable on said analogue scale at any position therealong, said tab including a light sensitive element opposite said analogue scale so that when a scale mark opposite said light sensitive element illuminates, said tab provides a signal.

6. A display device as claimed in any preceding claim, including at least one auxiliary numeral indicator for indicating numerals of a higher order of a measurand.

7. A display device as claimed in Claim 6, wherein said auxiliary indicator includes means for indicating the polarity of the measurand.

8. A display device as claimed in Claim 6 or Claim 7, wherein said auxiliary indicator includes means for indicating the measuring range of said instrument.

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

Claims

**WARNING** start of CLMS field may overlap end of DESC **. ing, which obviously indicates the decimal point, the mark 6 has an appearance deviating from the surrounding, indicating the numeral 4 of the measuring value, and the second display element 1 to the right of it has an appearance differing from the surrounding, indicating the numeral 2 of the measuring value. If the measuring value slowly increases, the second display element 1 to the right of the mark 6 resumes its initial condition, not deviating from the surrounding, and in its place, the third element 1 to the right of the mark 6 assumes an appearance deviating from the surrounding etc. As soon as the measuring value reaches 3.50, the mark 6 resumes its initial condition, not deviating from the surrounding, and the mark 7 which indicates a 5, assumes an appearance differing from the surrounding. For a decreasing measuring value, this process occurs in the reverse sense. The control of the numeral segments of the numeral indicator 5, and of the decimal point, the minus sign, and the range overload indicator thereof, occur in the conventional way. In the above it has been assumed that at any time only a single display element 1, 2 or 3 has an appearance differing from the surrounding. The mark concerned thereby resembles the tip of the pointer of a pointer instrument. However, it can also be arranged that all display elements to the left or to the right of the display element indicating the instantaneous measuring value, also have an appearance differing from the surrounding. In that case, one obtains a presentation corresponding to the mercury column of a mercury thermometer, in which the transition between the display elements which do and do not deviate from the surrounding, indicates the measuring value. A measuring instrument of the type described is a favourable combination of digital and analogue presentation. With the exception of the numeral of the lowest order of the instantaneous measuring value, all numerals of the measuring value are presented directly and digitally, so that they can be read at a glance. The numeral of the lowest order but one of the instantaneous measuring value is not only presented digitally, but also analog ously (since the location where that numeral is displayed depends upon the value of that numeral). The numeral of lowest order of the measuring value is displayed exclusively in an analogous way. If the measuring value fluctuates, the display elements 1, 2 and 3 which deviate from the surrounding change correspondingly. Each of them therefore deviates from the surround ing only during part of the time, and the range within which the measuring value fluctuates can thereby be observed, with or without flicker, dependent upon the fluctuation fre quency. Because of the inertia-free presentation, this is true even for high fluctuation frequencies. A measuring instrument of the type referred to is excellently suitable for signalling limit values. For that purpose, a rail or slot can be provided alongside the scale, along which two or more tabs 9 can move. Each of these tabs carries a light sensitive element (e.g. a photodiode) which provides a limit value signal as soon as the underlying display element 1, 2 or 3 assumes an appearance deviating from the surrounding. This can be done very easily if the display elements 1, 2 and 3 light up in that they are provided with light emitting diodes, gas discharge larnps or incandescent lamps, but is also possible if the display ele ments 1, 2 and 3 have an optical transmission coefficient or reflection coefficient dependent upon the control, such as when using liquid crystals, provided that sufficient ambient light is available, or a light source is available. WHAT WE CLAIM IS:-

1. An instrument display comprising an analogue scale having a basic unit of division and multiples thereof, a plurality of numeral indicators located parallel to said analogue scale, each of the said numeral indicators being physically connected to a multiple unit of said analogue scale so that as a measured parameter equals or exceeds an anlogue scale multiple value, the numeral indicator connected thereto changes state to visually indicate a more significant digit related to said multiple value, a less significant digit being indicated on said analogue scale.

9. A display as claimed in any one of Claims

6 to 8, wherein the auxiliary indicator includes means for indicating a decimal point.

10. A display as claimed in any preceding claim, wherein said analogue scale and said digital display devices are arranged in a row.

11. A display as claimed in Claim 10, wherein said numeral indicating means is located at the end of the row which relates to the lowest absolute measuring value.

12. An instrument display substantially as hereinbefore described, with reference to the accompanying drawing.