GB2312510A

GB2312510A - Electronic ruler

Info

Publication number: GB2312510A
Application number: GB9608779A
Authority: GB
Inventors: Nigel Geoffrey Ley
Original assignee: Individual
Current assignee: Individual
Priority date: 1996-04-27
Filing date: 1996-04-27
Publication date: 1997-10-29
Also published as: GB9608779D0

Abstract

A multiple scale and multiple function measuring and drawing instrument has one or more displays comprising electronic display screen means and is controlled by an internal microprocessor so that a wide variety of different scales of measurement, calculations and other useful information may be displayed and manipulated from one instrument. Using control buttons 6 and 9 a full length scale, 5, a single scale mark 2 or a group of scale marks 15 may be shown. As an electronic and computerised ruler embodied in a suitable encasement the instrument's display means is largely transparent so that it can be viewed through for alignment over marks to be measured. Expansion modules may be connected to extend the capabilities of the instrument and an alignment extension pointer arm (30, Fig.10) may be added to reach beyond any edge gap between a drawn mark and the edge of the rule.

Description

Measuring & Drawing Instrument.

This invention relates to a measuring and drawing instrument.

Rulers are well known measuring and drawing instruments comprising a straight linear strip with smooth parallel guide edges for drawing straight lines on paper or other medium, and displaying, adjacent the longitudinal edges, the calibrated marks of one or more linear scales by reference to which distances between points can be measured, or, by alignment with a pen, marks made for connection by a straight line.

Additionally some rulers incorporate a protractor scale so that angles may be measured and drawn. More than one scale can be provided for each edge by dividing the adjacent display surface into display zones, each devoted to a particular scale. The number of scales can also be increased by increasing the number of edges. One method of increasing the number of edges is by incorporating one or more slots along the length of the rule.

Special types of trade-specific ruler are also available such as for printers and typographers who need to measure type sizes in an appropriate unit of scale such as picas, ems and points.

There is another printer's ruler known as a Universal Computer Rule for measuring the depths and widths of continuous stationery forms and for determining the number of print lines for a given line feed and font size.

Typically rulers are made of wood, plastic or metal with a flat base and slightly bevelled upper surface. However, rulers can also be cylindrical or of other geometric cross section, such as triangular, square, octagonal or any shape as may increase the rulers scales and functions. Some rulers have a raised finger grip running centrally the length of the rule which adds steps or shoulders to the shape of the instrument.

Whereas a wooden or metal ruler is always opaque, so that a viewed scale is on the uppermost surface, a plastic ruler can be either opaque or transparent and the viewed scale can therefore be on either the upper or underside surface. Very often rulers embody comparative scales such as imperial and metric, the scales being imprinted, etched, moulded or stamped upon the display surfaces of the ruler. Invariably, a basic unit of scale is subdivided into a range of progressively smaller units of scale. For example, a metric scale in centimetres may have each centimetre subdivided into millimetres and an imperial scale in inches may have xach inch subdivided into halves, quarters, eighths and so on down to sixty-forths. Thus the typical ruler is a multiple scale, multiple function instrument.

With some traditional rulers, especially those produced by mass production in plastic, there is a narrow gap between the edge of the ruler and the marks of scale displayed on the external surface, such that contiguous alignment of a scale mark with either a pen tip or a drawn point, is impossible. This requires an exercise of judgement on the part of the user in making the required alignment and can give rise to small errors in accuracy. A similar gap will necessarily arise in any ruler in which the scale marks are embodied internally within a transparent substrate or encasement. Although such a gap is not always critical, where it is impossible to eliminate such a gap entirely, an extension arm or pointer movable along the rule, may be introduced to transfer a line aligned with a scale mark, beyond the edge of the rule, said arm being, for example, a tight fit within a suitable channel or mounted on a track or rail. Optical means, such as a prism incorporated into the ruler's edge, may also serve the same purpose.

Whilst conventional rulers as referred to above are relatively inexpensive to manufacture, they are not without their drawbacks in use. A particular problem arising from the progressive division of the basic unit of scale is that the eye is presented with a confusing amount of visual detail, with the gap between division marks becoming smaller and smaller until a stage is reached where it is difficult to identify the correct two division marks which should be aligned with a pair of points whose apartness is to be measured. Quite often the second point will fall within the gap between two adjacent division marks and require an assessment of the proportion of length that needs to be added to the overall length. Similarly the alignment of a writing instrument with a division mark for the purpose of marking off becomes progressively more difficult. It may be necessary to resort to a magnifying lens to enlarge the image for improved accuracy.

Moreover, the scales are permanently fixed and thus are incapable of manipulation or movement along the length of the ruler.

An ideal ruler may be considered to be one displaying just two division marks capable of occupying any position along the ruler with a calculation of their separation being automatically displayed.

An object of the present invention is to provide a universal multiple scale and multiple function measuring and drawing instrument capable of displaying, from a stored repertoire of specific scales of measurement, any chosen scale in as great or little detail as the user may require, from full scale format to just one or two division marks, each controllably movable along the length of the ruler. A further object is to simplify the alignment of the two appropriate division marks of scale that correspond with the distance between two points it is desired to accurately measure, by displaying just two division marks, each controllably movable along the length of the ruler until the respective marks are aligned with the respective points, and, conversely, to simplify the alignment of the tip of a writing instrument with any desired division mark by displaying said mark individually so that a point can be accurately marked off. Yet a further object is to simplify the calculation of distance between drawn points by automatically displaying a digital readout of the measurement, thereby eliminating the need to count and sum the scale division marks of different measurement units. A still further object is to provide an instrument capable of coupling with other sources of useful data, such as remote computers, and displaying that data or transmitting data to the remote computer.

Thus according to this invention there is provided a drawing and measurement instrument comprising electronic screen display means for selectively displaying calibrated scales of measure; display drive means and control means for manipulating the calibrated scales in such a way that a desired scale or individual components of such scale can be selected by the user and put on view; electronic data storage means for holding user data; stored digital program means; input and output means for enabling the user to select and manipulate the display means and other inbuilt functions; attachment means for enabling add-on program and memory modules and other types of external devices and accessories to be attached and securely connected for interfacing with the instrument, and protective housing means including a base substrate for enclosing the aforesaid means along with an electrical power source.

Various technologies offer alternative implementations of a drawing and measurement instrument with a display means in accordance with the present invention. For example, the display means could be provided as arrays of multiplexible subminiature light emitting diodes in which each diode represents a mark of unit measure. Alternatively a suitable display could be provided in the form of an electroluminescent panel or a gas plasma vacuum display tube. The aforementioned technologies could also be usefully combined to provide a hybrid display of primary and secondary display means. Preferably, however, the display means, or the principal display means, is provided in the form of a liquid crystal display in which the multiplexible cells containing the liquid crystal material represent the marks of unit measure. Such a display means may be provided as a microprocessor-controlled video display screen or may comprise a multiple layer of transparent LCD screens, each of which may be dedicated to a particular pre-etched measurement scale or function. Either or both negative or positive imaging may be used for the marks of division measure. In a negative mode the LCD cells will represent light apertures or shutters through which a source of backlighting can be projected onto a translucent screen surface of an outer ruling edge.

An electronic and computerised ruler and drawing instrument as described herein has the capability of providing in a single instrument most or even all of the typical scales of measurement available from a multitude of conventional rulers.

Additionally, such a ruler may also provide other types of scales for comparative purposes as, for example, in comparing scales for clothing and shoe sizes of various countries, or tonal percentage dots for printers, or temperature scales such as Celsius and Fahrenheit. For printers it would be advantageous to have available a collection of font styles in different sizes as an aid to selection of typefaces. These and many other uses may be provided for. For example, with the instrument being essentially transparent for viewing through, navigators may be aided by the computing and calculation features, in the measurements they make on maps, gaining automatic calculation of nautical miles at sea and translating measured distances into miles or kilometres for navigators by sea, land and air. A ruled musical scale may be provided for composers to write bars of music on and save and retrieve later. Gatherers of statistical information may also be aided by using the ruler to measure and count entries of, for example, company names in trade directories.

The conventional method of fabricating LCD displays is with flat plates of glass coated with a transparent conductive medium such as Indium Tin Oxide, and suitably etched by photolithography with a front and back electrode pattern of cells into which the LCD material may be introduced to form a sandwich construction with external polarising foils. The glass plates also carry an alignment layer which is rubbed with a roller to produce a surface on which the liquid crystals will align in a preferred direction. After the application of a spacing layer the display so formed has to be sealed at the edges and consequently the pattern of cells creating a desired image cannot normally be taken all the way to the edge of the glass. The cells are electrically driven using a multiplexing scheme, usually employing an alternating current. This method is of course useable with the present invention. Flat glass plates are used for ease of manufacture of the display but a LCD display does not have to be a flat. It could be curved or formed to a specific shape as desired. Preferably, however, the LCD display for the present invention is provided as a pair of corresponding shaped plates in which one plate is able to nest within the other so as to provide a curved edge.

The display screen may be partly or wholly transparent so that a displayed scale can be laid over a drawn mark and the mark viewed through the display screen.

A specific embodiment of the present invention will now be described by way of example with reference to the accompanying drawings in which: Figure 1 shows a plan view of the drawing instrument; Figure 2 shows a front side elevation of the ruler; Figure 3 is an end view illustrating a partial cross-section; Figure 4 is a closed end view; Figure 5 shows in perspective a schematic of a back-lit LCD display arranged in negative mode; Figure 6 illustrates a schematic of a wrap-round thick film LCD sandwich; Figure 7 shows a a front side elevation; Figure 8 shows an end view of an alternative embodiment; Figure 9 shows in perspective a schematic of a LCD panel incorporating a reinforced drawing edge; Figure 10 illustrates the use of the drawing instrument employing a transfer pointer arm; and Figure 11 is a schematic side view of a sandwich of glass plates combined with a thick film conductive membrane.

Referring to the drawings the double-edged measuring and drawing instrument comprises one or more electronic display screens 5 and 14 mounted beneath an encasement housing 16 above a conjoined rigid base substrate 17 as shown in Figures 1 and 2. The base substrate 17 serves as a former for supporting the electronic display screens at a suitable angle or bevel.

The display screens may be provided either as discrete display screens or panels, or may be arranged as dedicated display zones 1, 5, 11, 12 and 14 within the display means, said means preferably comprising multiplexible, transparent Liquid Crystal Displays driven under microprocessor control in accordance with user commands selected from a repertoire of pre-programmed routines and functions stored within a solid state digital memory such as a ROM.

Microprocessor circuitry together with associated logic and memory components will be well known to persons skilled in the art and are not shown, such circuitry being provided within housing 16.

Electrical power may be provided from a mains adaptor accessory (not shown) connected to power socket 10, by one or more battery cells inserted within housing 10 via removable end caps 7 and 19, or by by a solar cell 3, the instrument being activated by means of a ON/OFF switch 36 within recess 37.

Control buttons 6 and 9 are provided within housing 10 and enable the user to input selection commands through a scheme of scrolling through available commands displayed in turn in menu form in one of the dedicated screen display zones 1, 11 or 12.

The number of control buttons is not confined to two and are shown by way of example only.

A pad of input keys 4 are provided within housing 16 to enable the entry of numeric and or alphanumeric information in connection with additional control of the instrument. For example, after using control buttons 6 and 9 to bring up a full length scale as shown at 5 in Figure 1, a suitable combination of the input keys may be used to suppress the scale so as to show a single scale mark 2 or a group of scale marks 15 as shown on display screen 14, or to manipulate the scale marks at will. For example a single scale mark may be displayed and then made to appear to advance or retreat along the length of the rule by sequentially switching on and off concealed but adjacent marks.

At ends 20 and 21 there may be provided edge connectors to enable additional devices, program and memory modules to be attached to expand the capabilities of the instrument. One or more accessory sockets 8 may also be provided for the same purpose. Many types of accessory modules may be provided, including a foldable, full size Qwerty keyboard, a cellular telephone module with earphones, microphone and ariel, modules for childrens games and miniature digital television means if so desired. Functions such as electronic calculator, clock, calender, dictionary, Thesaurus, spelling checker, notebook, games and educational features may all be provided within the one instrument. Children, for example could be encouraged to learn their multiplication tables and their progress be rewarded with access to an in-built video game.

An edge connector 22 is shown in Figure 4. In Figure 3, representing the opposite end, the numerals 23 and 24 denote the interior spaces for accommodating the instrument's internal microprocessor circuitry and in which an additional edge connector may be housed. Alternatively, a Smart Card reader may be provided therein to enable additional programs and memories to be inserted in the form of a Smart Card. Interior spaces 38 and 39 are available for accommodating multiple layers of LCD displays in a sandwich or laminate form.

Since conventional LCD's are fabricated in the form of flat glass plates their use in a multiple layer or sandwich arrangement in accordance with this invention, may result in undesirable bulk or thickness. To therefore minimise this there may be provided an arrangement as shown in Figure 6 utilising a flexible, transparent conductive thick film 27 wrapped tightly around a glass plate 25 and compressed flat by second plate 24. Such an arrangement would lead to fewer glass plates by enabling the plates to be etched with cells on both sides as shown in Figure 11 where plates 24 and 25 illustrate example cells 2, 40, 41 and 42. Similarly, the conductive membrane 27 would be coated with Indium Tin Oxide on both surfaces. An advantage of such an arrangement is to greatly increase the surface area available for laying out conductive tracking for interconnection with cells or video pixels on the glass. This arrangement could of course be reversed with the glass carrying the conductive tracking and the membrane being etched with the pattern of cells. The membrane 27 would be be securely anchored by, for example, register pins and the external edges suitably bonded and sealed.

Although in these drawings the glass plates are shown with flat edges they may also be provided with rounded edges or be moulded so that one plate may be nested to correspond within another. This shaping is shown in Figure 3 where the display screen is denoted by the numeral 43. This shaping is desirable to enable marks of scale to appear at the edge of the rule with minimal gap. Alternatively, the instrument may incorporate a source of backlighting such as a photoluminenscent panel 26 as shown in Figure 5 with the LCD plates 24 and 25 operated in negative mode as a light shutter, enabling light to pass through an open cell 2 and impinge on a translucent outer layer, other cells 28 remaining blacked out.

Although glass is the usual medium for making LCD's, transparent plastic is also a desirable medium for use in providing a ruler in accordance with this invention, having the advantage of strength and flexibility.

In Figures 1 to 4 the electrical component housing is shown positioned centrally along the length of a double edged rule.

However, the instrument is not confined to such an arrangement and the housing may be placed at any convenient position or a single edge 17 be provided as shown in Figures 7 and 8 where the housing 16 is separated and placed at the ends of the ruler with expansion modules 22 inserted adjacent thereto.

Optionally, a reinforced drawing edge 29 may be incorporated as shown in Figure 9. Such an edge would protrude only slightly from plates 24 and 25 so as to prevent a critical gap between marks of scale 2 and the edge of the ruler.

Finally, as shown in Figure 10, to overcome any critical gap, the instrument may be provided with an extension pointer arm 30 slidably movable within a precision channel 35 or other suitable tracking means, enabling accurate alignment of the pointer with a drawn mark 33 on a sheet of paper by reference to displayed scale mark 2 aligned on LCD display 5 with a permanent alignment mark 32 as viewed through an aperture or magnifying lens 34. When so aligned in use the control buttons would be used to reset or zero the scale. The pointer may then be moved along the rule to align with another drawn mark and displayed mark of scale and the control button used to return the result of the measurement made for display in one of the LCD display zones or windows 1 and 12. It is anticipated that two control buttons would be sufficient to operate the selection of a desired function or routine by scrolling through a menu of choices driven by a FOR/NEXT program loop, one button being used to accept a displayed choice.

Of the many various types of Liquid Crystal that are useable in connection with this invention a preferred type is the Ferroelectric crystal. This has the advantage of consuming less electrical power by permitting a displayed image to remain on display without power applied. Thus a drawing and measurement instrument in accordance with this invention may display a full scale in the fashion of a conventional ruler without drawing current.

It should be understood that the embodiment of this invention as described above is not the only embodiment capable of implementation in accordance with the objects of this invention and that the drawings, while relating to a specific embodiment, may be amended and modified according to tastes of style, current technological practice and design to many other possible embodiments, original concepts frequently being refashioned in appearance whilst retaining their essential essence. It will be recognised that the essence of this invention is that the measuring and drawing instrument that has been described takes the form of a digitally programmable microprocessor controlled electronic display screen, and may be applied to many similar drawing instruments such as a draughtsman's cursor with displays or protractor.

Claims

CLAIMS What I claim is as follows: 1. A drawing and measurement instrument in which the information and calibrated scale display surfaces comprises one or more electronic, flat-panel display means activated and controlled by a digitally programmable microprocessor integrated within the instrument.
2. A drawing and measurement instrument as claimed in Claim 1 in which the electronic display means comprises a liquid crystal display panel.
3. A drawing and measurement instrument as claimed in Claim 1 wherein the electronic display panel means comprises an arrangement of light emitting diodes.
4. A drawing and measurement instrument as claimed in Claim 1 wherein the electronic display means comprises an electroluminescent panel.
5. A drawing and measurement instrument as claimed in Claim 1, wherein the electronic display means comprises a gas-vacuum display tube.
6. A drawing and measurement instrument as claimed in Claim 1 wherein the electronic display means comprises a gas plasma panel.
7. A drawing and measurement instrument as claimed in Claim 1 wherein the electronic display means comprises a field-emissive display panel.
8. A drawing and measurement instrument as claimed in Claim 1 wherein the electronic display means comprises a light emitting polymer panel.
9. A drawing and measurement instrument as claimed in Claim 1 wherein the electronic display means comprises a flat cathoderay tube.
10. A drawing and measurement instrument as claimed in Claim 1 wherein electronic digital memory means is provided for storing digital programs and comparative information display routines.
11. A drawing and measurement instrument as claimed in Claim 1 wherein interface means is provided for interconnecting the instrument with external peripheral devices.
12. A drawing and measurement instrument as claimed in any preceding claim, wherein multiplex switching means for simulating movement of an electronic cursor, is provided in order to display at selected positions of calibration marking, one or more display marks for alignment with drawn marks whose apartness beyond the instrument edge is to be measured.
13. A drawing and measurement instrument as claimed in any preceding claim, wherein mechanical cursor means comprising an extension pointer arm slidably movable along the length of the instrument, is provided for alignment with selected calibration marks close to the edge of the instrument and with the drawn marks whose apartness is to be measured beyond the edge of the instrument.
14. A drawing and measurement instrument as claimed in Claim 1 and Claim 13 wherein the cursor is provided with a registration hairline and magnifying lens for accurate alignment with drawn marks.
15. A drawing and measurement instrument as claimed in any preceding claim, wherein the calibrated display panel has a gently sloping surface.
16. A drawing and measurement instrument as claimed in Claim 1, or Claim 2, or Claims 10 to Claim 15, wherein the liquid crystal display means is provided within a circuit-patterned flexible membrane satchet, conformable with the surface of the instrument's substrate.

17. A drawing and measurement instrument as claimed in Claim 2 or Claim 16 wherein the liquid crystal material is a ferroelectric liquid crystal.
17. A drawing and measurement instrument as claimed in any preceding claim wherein a key-pad of two or more keys is provided for operation of the instrument.
18. A drawing and measurement instrument as in any preceding claim, wherein a solar panel and a battery compartment are provided in order to provide electrical power to the instrument.
19. A drawing and measurement instrument substantially as described herein with reference to Figures 1 to 11 of the accompanying drawing.