WO2006070125A1

WO2006070125A1 - Bathroom scale

Info

Publication number: WO2006070125A1
Application number: PCT/FR2005/003256
Authority: WO
Inventors: Bénédicte SIMOND; Patrick Juteau; Benoît LINGLIN
Original assignee: Seb S.A.
Priority date: 2004-12-23
Filing date: 2005-12-22
Publication date: 2006-07-06
Also published as: FR2880112B1; EP1828730A1; RU2386110C2; CN101080197B; CN101080197A; FR2880112A1; CN101084418A; RU2007127890A; CN101084418B

Abstract

The invention concerns a bathroom scale (1) comprising a weight-receiving platform (2) supported on a weighing base or stand including at least one weight sensor connected to a measuring circuit which sends a measurement signal to a computing unit and means for automatically storing the measured values or reference values, as well as a control circuit which compares the current measured value with a previous measured and/or computed and/or stored value. The invention is characterized in that said control circuit controls, based on the result of the comparison, at least one lamp (6, 10) illuminating a zone (3) of the platform (2) such that it remains visible to a user stably positioned on the platform, whatever the orientation or the size of his/her feet relative to the platform (2).

Description

WEIGHER

The present invention relates to a weighing apparatus, in particular a scale, particularly of the electronic type comprising strain gauges associated with an electronic measuring circuit delivering a signal which is a function of the weight to be measured and more particularly the display of the measurement results.

In principle, a weighing apparatus comprises a platform capable of receiving the weight to be measured, at least one test body comprising on one of the faces strain gauges, one of the ends of this body being connected to the plate and the other to a pedestal or foot intended to rest on a flat surface. The two ends of this body are embedded in the plate and the base and they define a bar of an elastic material supporting the strain gauges and deformable essentially by bending under the effect of the weight to be weighed. The gauges are connected to an electronic circuit for converting the deformations undergone by the gauges into electrical signals and transforming the latter ¹ into numerical values corresponding to the measured weight.

The weighing plate is generally made of a rigid material capable of withstanding compressive and tensile loads in order to resist without deformation to the applied load. A display window is usually spared in the front part of the tray and reveals a display type LCD or LED below. These displays have the disadvantage of being difficult to read remotely by the size of the characters displayed. Increasing the size of the characters displayed considerably increases the price of the display and therefore of the device.

EP 0 377 941 discloses a weighing scale comprising a weighing platform of circular shape supported by a base of the same shape. The base contains a weighing mechanism that transforms, through a system of levers, the axial movement of the plateau, caused by the rise on the plateau of a person, in a rotational movement of an indicator needle located in the center of the plate. The tray has a transparent cover affixed to a graduated plate having numbers inscribed at its periphery, the indicator needle passing through this plate in its central part. When the user climbs onto the weighing pan, the needle moves proportionally to the applied weight and its tip points to a peripheral graduation. This type of display can certainly be easily read by a user standing on the device, but even if the indicator figures have a large size, the needle can be hidden by the feet. In addition, such a device has a significant thickness due to the large vertical movement between the plate and the base of the device. In addition, this device finds these limits when one wants to read its indications in a place which is not sufficiently enlightened.

JP 59 051312 discloses a scale comprising an LCD display capable of displaying the measured value of the weight and, at the same time, by arrows, the loss or weight gain compared with an earlier weighing stored in the memory of the device. However, the indications provided by such an LCD display have a very low brightness, so that the display must be connected to the device with a flexible cable to allow the user to approach the view. Such a solution does not meet criteria of low cost and small size of the device.

The document JP 60 161533 offers a solution to this problem by proposing a display permanently mounted on the plate of the apparatus, but, however, having an LCD display of the current value measured and display arrows of the relative evolution. to an earlier measurement stored in memory, but which are very discrete, being appended to the same display. This type of display has, on the one hand, the disadvantage of being even less visible than the previous one and, on the other hand, requiring the intervention of the user to store the current value by pressing on a switch button. As a result, if the recording user of the current measurement is forgotten, the device may display a false change. Another solution has been described in EP 1,125,550 which describes a weighing scale impedancemeter thin, which comprises a measurement electrode plate made of a transparent material and a base supported by weight sensors. The apparatus includes an LCD type display which is visible through a window of the tray. The display is illuminated by an LED to make reading digits easier when the unit is located in a poorly lit area. In addition, the apparatus may comprise three LEDs each indicating, by a different color, the degree of corpulence of the individual by comparison of the measured fat mass with pre-established standard limits. These LEDs are adjacent to the display being provided to illuminate only the screen of the LCD display and make visible the figures it displays. However, for these indications to be readable when illuminated, the display must be large enough, so expensive, so that the numbers can be read remotely, the person standing normally on the measuring platform. Such an LED arrangement involves imposing on the user a certain position on the measuring platform during weighing, a position which is further defined by the position of the electrodes indicated by protuberances on the plate.

The object of the present invention is to remedy, at least in part, the aforementioned drawbacks and to propose a scale capable of clearly and remotely indicating the trend of evolution of the weight of an individual when the latter is standing standing on the measuring platform, while allowing for advantageous designs of the device.

Another object of the invention is to propose a simple, mnemonic and visual mode of representation of the evolution of the weight of an individual when it is weighed on a scale.

Another object of the invention is a scale adapted to indicate the evolution of the weight of an individual by visual means capable of creating a strong impression on the user, which are visible even in places with little or no light , while using low-energy means.

Another object of the invention is an economical scale, not requiring a digital display or having an economical digital display.

Another object of the invention is a scale having a thin profile and an advantageous aesthetic appearance, capable of being mass produced for a low cost of industrialization.

These goals are achieved with a scale comprising a weight receiving platform supported by a weighing base or a base including at least one weight sensor connected to a measuring circuit which sends a measurement signal to a computing unit and means for storing the measured values or reference values, as well as a control circuit which makes a comparison between the measured current value and a measured previous value and / or calculated and / or stored in memory, due to that said control circuit controls, according to the result of the comparison, at least one lamp illuminating an area of the tray so that it remains visible to a user standing in a stable position on the tray, whatever the orientation and size of his feet in relation to the plateau.

Such a device is already able to measure the weight of a person who is standing on the weight receiving platform of the apparatus (it is understood the area of the apparatus on which the load to be weighed is applied) and to put in memory the measured value. The apparatus also comprises a calculation unit that is able to perform the comparison, for example the difference between the measured weight stored in memory and a current value measured. This comparison can also be made between the current value measured and a target value entered by the user or calculated by the device according to the size that the user enters into memory using a keyboard or according to results of previous weighings he has made.

Indeed, it has been noticed, following user tests and observations made, that users are interested in knowing more about the evolution of their weight than their exact day-to-day value. A scale according to the present invention thus provides, by a light effect, the display of the difference of the measured weight with respect to a value stored in memory, without using a digital display, the latter may be absent or off when taking measurements.

More particularly according to the invention, the result is represented in the form of a luminous display of a zone of the plate which has a sufficiently large surface so that the illuminated area of the plate is never completely hidden by the feet of the plate. user or while this illuminated area is on a surface on which the user does not set feet such as between his two feet. Indeed, to have a stable position during a weighing, the projection on the weighing surface of the center of gravity of the user must be in the center of the support polygon defined by the position of the feet. The greater the area of the lift polygon, the easier it will be for the user to keep their center of gravity within this polygon and the more stable it will be during weighing. As a result, the area between the user's feet and usually in the center of the weighing pan is a visible area when weighing. Thus, by arranging a luminous display in this zone, one can not only have a visible luminous indication of the result of the measurement, but also have a more discreet and economic light display, while remaining visible whatever the position of the feet of the light. the user on the weight receiving tray.

Such a scale scale allows both weighing in any place of the user's choice, even if it is completely dark, without an external source of light. The user can thus receive the result of his weighing with respect to a reference weighing clearly and remotely, while leaving free the choice of the design of the device, the location of the latter and, at the user, how to stand on the board and when to weigh, the result being perceived strongly, without having to make the effort to read or retain the figures reflecting the value of its weight. The seat area of the feet occupies part of the surface of the tray when the feet of the user support for the measurement. This area varies depending on the size of the users' feet. Thus, for women, an average size has a length of 237 mm, a width at the toe articulation of 91 mm and a width at the heel of 63 mm and the dimensions of a maximum size are: length 267 mm, width at the finger joints of 99 mm and heels of 68 mm. For men, an average size has a length of 260 mm, a width at the toe joint of 98 mm and a width at the heel of 65 mm and the dimensions of a maximum size are: length of 293 mm, finger joint width of 108 mm and 73 mm heels. These dimensions can still vary according to the morphology of the individuals of the different countries. The apparatus of the invention takes into account these dimensions and is made so that said light zone is sufficiently large or extended or formed of small areas scattered on the plateau so as to exceed at least the maximum length and / or the maximum width of the feet of the user or to be located between the feet of the individual standing on the measuring platform.

Such a scale has an advantageous aesthetic, the measuring plate having a uniform appearance (the display being off or absent) before the user goes up on the measuring platform, and illuminated as soon as the measurement and the calculations are carried out, which reinforces the perception of the result by the user. The apparatus of the invention thus offers, for an advantageous design, an economical and reliable solution for displaying the evolution of the weight and calculated by the apparatus.

Advantageously, said lamp always illuminates the same area of the weight receiving plate.

This solution is more economical, because it is necessary to arrange a single zone of the plate so as to be able to receive a luminous display, the indication of the result only by controlling the lamp.

Preferably, the lamp (s) is or are controlled to indicate the result of the comparison by a color change.

It would have been possible, of course, to envisage a solution comprising a single luminous lamp of a single color, its state of continuous supply then being able to testify to a weight gain compared to the previous measurement, its setting in blinking of a loss of weight and, in the off state, a consistency of the weight for the last measurement. However, an indication is preferred by a change of colors, because a well-defined color code makes a stronger impression on the user.

Advantageously, said illuminated area of the plate has an area equal to at least 1/25 of the total surface of the plate

It is understood that in this embodiment, it is a continuous luminous surface, but placed so as to be spread over a sufficiently large area of the plate so that it is visible and that it produces at the same time a strong and clear impression to a user standing on the measuring platform, regardless of the user's orientation and the size of his feet.

Preferably, said illuminated zone is the central zone of the plate and / or a peripheral zone bordering it.

In particular, in the context of a circular-shaped tray, square or other, when there is no mark for the base of the feet, the user can hide the area of a front display or that of a possible other light area punctual or having small dimensions. Thus, when the display is located in the central area of the tray or on the periphery of the latter, it can never be completely hidden by the feet of the user pressing on the measuring plate. A display placed in this central area may be more discreet, while remaining very visible. By way of example, such a display may comprise at least one LED placed in the center of the plate illuminating the central part of the plate, or even several LEDs each defining a distinct light zone, but being arranged at a short distance from one of the other. Such a central bright area of the board must fit in a minimum area of foot-off defined by a circle with a maximum diameter of 100mm so that the user can climb on the board in any direction, even at night or even in a dimly lit place, stand upright and get your weighing result in a visible manner.

By zone bordering the central zone of the plateau, it is understood that it is a single zone remotely surrounding the central zone, completely or substantially (for example at least 2/3) of its peripheral contour or that it is at least two zones located on either side of the central zone. Such a peripheral contour may then be open or closed, for example having a circular annular shape, rectangular or any shape, but being disposed on a large periphery around the central area of the tray.

Advantageously, at least part of the visible face of said plate is made of a translucent material or transparent to light or has at least one receiving cavity of said light display.

This makes it possible to place the lamps or a part of the light-emitting device in the lower part of the plate, or even to fix them to the plate, in order to obtain a good restitution of the lighting, while favoring an advantageous constructive solution.

Preferably, the scale of the invention comprises at least two lamps of different colors or at least one lamp that can be illuminated with at least two different colors.

We could also have considered a solution with two or more lamps of the same color, but each illuminating a translucent zone of different color (for example red to show a weight gain or green to show a loss of weight, respectively orange for a stable weight), the different illuminated areas then regrouping in the central part of the plateau or in its periphery.

However, for reasons of ease of understanding by the user, as well as constructive construction, a solution using several colored lamps is preferred. For example, one could use two lamps in a color code easy to recognize: red, for weight gain, and green for weight loss, the constancy of the weight then being implied because no lamp would ignite when taking measurements. Optionally, a third lamp, for example white or orange, could also be considered to indicate a constancy of weight compared to the previous value stored in memory. Any combination of colors can then be used to obtain a wider range of colors and thus a finer communication by a preset color code.

Usefully, said lamp or lamps are LEDs.

The light emitting diodes have good brightness for a very small footprint and low cost. One could then use either a single LED and a light guide to cover the entire light area of the tray or use multiple LEDs with or without a light guide. This solution also has the advantage that a same area of the plate can be successively illuminated with several different colors.

In a preferred embodiment of the invention, said lamps are mounted on a support disposed under the plate so as to emit light towards a reflector looking at the plate.

This solution makes it possible to improve the scattering of light with few light sources, the light then being emitted in the direction of a reflector which sends it back amplified towards the plateau.

Advantageously, said support is arranged in the center of the plate.

It would have been possible, in a variant, to arrange the lamps on the periphery of the plate, but an arrangement in the center is preferred because, with a suitable reflector, a good illumination of the plate with fewer lamps is thus obtained. The support may be circular for a more uniform distribution of light towards the reflector.

Preferably, the illuminated area of the tray is made of an opal glass.

Opal glass is a translucent material allowing a good sifting of the light received from the reflector with a rendering of uniformity of the illumination over the whole area. This opal glass can be obtained by a deposit of enamel or paint on at least one of the faces of the glass and / or by chemical or mechanical attack of at least one of the surfaces of the glass. It can also be obtained by gluing on a glass plate with a translucent plastic film or by bonding a glass and an opaline.

In an alternative embodiment of the invention, the surface of said illuminated area is substantially equal to the surface of the tray.

Such an illuminated area on a comparable surface (equal to or slightly smaller) than that of the measuring plate of the apparatus produces a very strong impression on the user during his weighing.

Preferably, the scale of the invention comprises several light zones distributed substantially over the entire surface of the tray.

This solution then makes it possible to use a non-transparent or translucent plate, but comprising only cavities distributed on the plate and able to receive a lamp or to transmit the light emitted by one or more lamps located under the plate. Advantageously, the scale of the invention comprises a bundle of optical fibers.

A bundle of optical fibers makes it possible to illuminate several points of the plate with a single light source. A network of optical fibers arranged under the plate is thus defined, the end of each fiber then coming to the level of the surface of the plate. This solution makes it possible to effectively and economically disperse the light energy over the entire plate, since a single LED and a bundle of optical fibers suffice.

The optical fiber network may also consist of diffusing optical fibers, that is to say that they emit light over their entire length. In this case, the fiber network is arranged parallel to the surface of the tray.

In another embodiment of the invention, said lamps are electroluminescent lamps.

By electroluminescent lamps are formed lamps based on a phosphor layer sandwiched between a first transparent conductive upper layer and, with a dielectric, a second lower conductive layer. These lamps can take any form and are adapted to cover areas of large area, while having a very good brightness, evenly distributed on their surface.

Usefully, said electroluminescent lamps are adjacent to each other.

By installing electroluminescent lamps below the plate or a transparent or translucent zone of the latter, it is necessary to cover distinct zones, each zone having a different color and therefore a composition of the different phosphor layer or consisting of a single layer of phosphorus but having an additional layer of silkscreen comprising different colors and playing the role of a color filter. These zones are then advantageously adjacent, for example concentric for a circular plate, for reasons of constructive ease (eg wiring, etc.).

Advantageously, said previous value is an average of the weight calculated on the basis of several previous measurements.

It would have been possible to choose a single previous value measured and recorded by the apparatus as a basis of comparison with a current value, but it is preferred to use an average of the recorded weights, in particular over a duration equal to or greater than seven days, since it is more representative of the actual value of the measured weight. The calculated average may be fixed, for example being calculated once and for all on the basis of the first measurements; or it can be a sliding average, the average then being calculated over a reference period, but which is automatically shifted at each new measurement.

In addition, the unit of calculation of the apparatus could calculate, according to a more evolved version of the apparatus of the invention, the standard deviation in order to exclude the random variations of the weight and to better interpret thereafter the trend of changing weight. Limits of a stability interval could then be set, for example, to plus or minus three standard deviations around the calculated average weight value. A measured value that comes out of these limits could then be considered as representative of the weight evolution trend and it would then be taken into account by the control means which control the supply of the light lamps of the invention.

Preferably, the scale of the invention comprises a digital display of the measured values and a button for switching on said display.

Such a digital display could, optionally, display one or more digital values measured or stored in the memory of the device. This display would be controlled by the user when he also wants to know numerical values in addition to the trend of evolution. The display may be, for example, of the LCD or LED type.

The invention will be better understood with the study of the embodiments taken in no way limiting and illustrated in the accompanying figures in which:

- Figure 1 illustrates a top view of a measuring platform of a scale according to a variant of a first embodiment of the invention; FIG. 2 illustrates a view from above of a measuring platform of a scale according to another variant of the embodiment of FIG. 1;

FIG. 3 is a side view of a scale according to a second embodiment of the invention;

FIG. 4 is an exploded view of the apparatus of FIG. 3; FIG. 5 represents a third embodiment of the invention;

FIG. 6 illustrates a view from above of a measurement platform of a scale according to a variant of a fourth embodiment of the invention;

- Figure 7 illustrates a top view of a measuring platform of a scale according to another variant of the fourth embodiment of the invention.

The electronic scale 1 of the invention comprises a rigid plate 2 capable of receiving the weight to be measured, plate 2 supported, for example, by a weighing base (not shown) comprising four feet each containing a weight sensor. Such a weight sensor comprises a bending bar with strain gauges, bending bar mounted cantilever between a part of the foot coming into contact with the plate 2 and another part of the foot resting on the ground. The strain gauges are mounted on one of the faces of the flex bar and are connected by a Wheatstone bridge circuit to the electronic control circuit of the apparatus to convert the deformations undergone by the gauges into electrical signals, transform these last in numerical values corresponding to the measured weight. These values are then stored in the memory of the device. Furthermore, the apparatus may comprise a digital display 11 which, when switched on by the user who actuates a button 12, can display the measured current value or an earlier value stored in the memory of the device.

The weight receiving tray 2 according to the examples illustrated in the appended figures is a circular, rectangular or square plate of small thickness (for example between 4 and 20 mm) and is made of a transparent or translucent material, for example example tempered glass or a type of resin PMMA (methyl methacrylate). Alternatively, the tray may be made of any other material (plastic, wood, metal, etc.) and include an insert of transparent or translucent material (eg glass or plastic) or a cavity which, when illuminated by lamps below, form an illuminated area 3 of the plateau.

FIG. 1 illustrates a plate 2 of the scale 1 according to a first embodiment of the invention comprising at least one lamp 6 which is of the LED type. In this mode, the plate 2 more particularly comprises three 7,8,9 lamps arranged at a point of the plate inside a light guide 5. The lamps 7,8,9 are LEDs of different colors, for example. example the lamp 7 is a green LED that can highlight a loss of weight (negative difference compared to the last measurement), the lamp 8 is a white LED which then informs the user that its weight is stable (no deviation from the last measurement) and the lamp 9 is a red or orange LED that warns the user of a weight gain or a positive deviation from the last measurement stored in memory . Each lamp is controlled by a control circuit of the apparatus according to the signal corresponding to the weight difference between the current measurement and an earlier value stored in memory and according to the cited color code or other pre-established code.

The light guide 5 is an optical conduit which makes it possible to bring light, from a light source, in this case one of the lamps 7, 8 or 9, into a remote area devoid of other light sources. Thus, with only one of the 7,8,9 lamps on, the entire light area 3 is illuminated, which provides significant energy savings and extends the life of the batteries. This light guide can be made in various ways, in particular by using an optical conductive material that is to say integrating on at least one of its surfaces prisms to reflect the light in predefined directions, or even using a deposit of reflective paint on the walls of a duct practiced in the thickness of the plate.

Such a light guide surrounds the sitting area of the feet. Thus, for a single foot-sitting zone centered in relation to the center of the plateau, and, for example, for the usual morphology of the feet of the European ethnicity users, this guide must have a main dimension (length or diameter) d about 300 mm; a smaller dimension could also be considered for a line that could then be seen between the feet.

Alternatively, this light guide can border two foot sitting areas on the same measuring plate, a light guide is then provided to form a light area around each foot. In this case, it is possible to envisage two light zones on the plate each having a periphery exceeding that of the footprint of a maximum foot of size, for example a rectangle of dimensions equal to or greater than 293 mm × 108 mm.

In another variant of the invention, a light guide may be provided to form a continuous light zone or luminous surface then called luminous footprint for each foot, or even covering a larger area so as to at least slightly exceed the area of sitting on both feet of the user standing on the measuring board.

FIG. 2 illustrates a variant of the embodiment of FIG. 1, the apparatus functioning in the same way, but where the plate 2 comprises several groups of lamps 7,8,9 provided along the light guide 5 to provide a more sustained light intensity to the light zone 3. For this, the lamps 7 are connected in series with each other, the lamps 8 are connected in series and the lamps 9 are connected in series also, each series of lamps circuit being controlled by the control circuit of the apparatus. In another variant not shown in the drawings, several groups of lamps 7, 8, 9 are provided all around the light zone 3, one side or a short distance from the other, and in this case the light guide 5 could, be absent.

Figures 3 and 4 illustrate views of a scale according to a second embodiment of the invention, the weighing base and the electrical or electronic components of the apparatus being omitted for clarity. The tray 2 of the scale according to this embodiment is translucent. A lighting module 20 is located below the plate 2 and comprises a support 21 on which are fixed several lamps 6 oriented so that they illuminate downwards, in the direction of a reflector 23. The support 21 is fixed by a thin foot 22 to the reflector 23. The reflector 23 is arranged parallel to the plate 2, its inner surface 24 has a parabolic shape and is covered with a light reflecting coating, for example a white paint layer. The light emitted by the LEDs towards the bottom of the apparatus, following the arrows in FIG. 4, is reflected by the reflector 23 upwards where it passes through the plate 2 made of an opal glass to illuminate a wide zone of this light. the last which then appears illuminated on the periphery of the support 21. In a variant, the support 21 may be made of a transparent material to further enlarge the illuminated area of the tray.

The support 21 may be a disk or cap comprising several LEDs distributed on its face opposite the reflector 23. For example, it is possible to have several LEDs emitting the colors: green, yellow or red according to the same color code as previously described. . In one variant, six red LEDs, six blue LEDs and three green LEDs can be arranged in order to be able to achieve the entire light spectrum and thus display more finely, with a wider spectrum, the evolution of the weight of the user. In another variant, one or more multi-color light-emitting diodes can be used which integrate several chips and are thus able to emit different wavelengths.

Figure 5 is a schematic representation of a scale scale according to a third embodiment of the invention. The plate 2 comprises several small orifices 27, preferably uniformly distributed over the entire surface of the plate, in each orifice being inserted an optical fiber 28 belonging to a bundle 29. The set of optical fibers 28 forming the bundle 29 is concentrated in the using a ring 30 which is placed in front of a lamp 6, which may be a multi-colored LED, and a collimation lens 31. The assembly formed by the lamp 6, the lens 31, the ring 30 and the beam 29 is held by a connecting ring 32 which can then be fixed to the plate 2 or the base of the device. When the lamp 6 is powered, the light energy that it emits at one end of the beam 29 is transmitted substantially completely, without losses, to the surface of the weight receiving plate 2, at the other end of the beam 29 of optical fibers. The optical fibers used are preferably polymeric optical fibers or FOPs, as their assembly is easier to perform and their cost is lower. The diameter of an optical fiber 28 is about 1 mm, which allows to have a good light, while facilitating their mounting to the tray 2, but remaining however discreet when the lamp is off. In one variant, it is possible to use a plurality of optical fiber bundles each connected to a specific color LED according to a predetermined color code.

FIG. 6 illustrates a plate 2 of the scale 1 according to a fourth embodiment of the invention comprising at least one lamp 10 which is of the phosphor-based electroluminescent lamp type. The entire surface of the plate 2 is transparent and comprises, arranged below, three electroluminescent lamps 14,15,16 of different colors arranged in concentric circles. By way of example, the peripheral lamp 14 emits a green light when energized, the intermediate lamp a white light and the lamp 16 located in the central zone an orange light, each being controlled by a control circuit of the apparatus according to the signal corresponding to the weight difference between the current measurement and an earlier value stored in memory and according to a preset color code.

The electroluminescent lamps 14, 15, 16 are advantageously produced by a multilayer screen printing on a film and reported by gluing on the lower surface of the plate 2 or they can also be made by screen printing directly on the plate 2 of the scale 1. This screen printing multilayer consists of the following elements: a first translucent or transparent conductive layer, covered with a phosphorescent ink covered with a dielectric which is in turn covered with a conductive layer. The screen printing inks may be inks polymerizable with UV or require drying in a ventilated oven. Only the portion of the phosphorus directly between the two conductive layers will illuminate once power is applied. For example, the power supply is by a high voltage electrical signal (between 100 and 400V) and a frequency of a few tens to a few hundred hertz which then allows the phosphorus light emission. The power supply of the lamp can also be screen printed on the tray of the device and could, in a variant be transparent. The composition of the phosphor layer is different for each of the 14, 15, 16 electroluminescent lamps for a different color light emission by each lamp. Optionally, one can use a single phosphor to make the three lamps and add before or after the transparent or translucent electrode a screen printing layer of three different colors acting as color filters.

FIG. 7 illustrates another variant of the embodiment of FIG. 6, where the plate 2 comprises an opaque part 18 at the bottom, the other part of its plate being transparent and comprising three electroluminescent lamps 14, 15, 16 of the same type as those described with reference to Figure 3, but having another configuration to cover the surface of the affected medium. This solution is more economical than the previous one terms of material gain and cost of lamps, while providing bright areas large enough to be visible when taking measurements.

In operation, at first, the user normally weighs himself by climbing on the platform 2 of the scale 1. He actuates the button 12 to turn on the digital display 11 and reads the value of its weight. This weight is then automatically stored by the device or manually by the user by actuating a suitable button (not shown in the drawings). During the following weighings, the apparatus indicates to the user by a color code only the tendency of variation with respect to the value entered in memory highlighted by the luminous zone 3 of the apparatus. If desired, the user can press the button 12 to turn on the display 11 to read the exact value of its weight and simultaneously or successively its weight difference with respect to or previous values.

Other variants and embodiments can be imagined without departing from the scope of these claims.

In another variation, cold cathode or CCFL tube lighting could have been used.

It could be envisaged to use an electronic device connected to the lamps and to the control circuit, which device is capable of varying the light intensity or the color of the light zone 3 in a proportional manner to the weight difference observed.

One could also imagine having a wider range of colors so as to display more finely the trend of evolution of the weight, according to a pre-established color code.

Claims

1. Scale (1) comprising a weight receiving plate (2) supported by a weighing base or a base including at least one weight sensor connected to a measurement circuit which sends a measurement signal to a weighing unit. calculation and means for storing the measured values or reference values, as well as a control circuit which makes a comparison between the measured current value and an earlier value measured and / or calculated and / or stored in memory, characterized in that said control circuit controls, according to the result of the comparison, at least one lamp (6, 10) illuminating an area (3) of the tray (2) so that it remains visible for a user standing in a stable position on the board, regardless of the orientation and size of his feet relative to the board (2).

2. Scale according to claim 1, characterized in that said lamp (6, 10) always illuminates the same area of the plate (2) for receiving weight.

3. Scale according to one of claims 1 or 2, characterized in that the lamp or lamps (6, 10) is or are controlled so as to indicate the result of the comparison by a color change.

4. Scale according to one of claims 1 to 3, characterized in that said illuminated area (3) of the plate (2) has an area equal to at least 1/25 of the total surface of the plate (2) of receiving weight.

5. Scale according to one of the preceding claims, characterized in that said area (3) illuminated is the central zone of the plate and / or a peripheral area bordering it.

6. Scale according to one of the preceding claims, characterized in that at least a portion of the visible face of said plate (2) is made of a translucent material or transparent to light or has at least one receiving cavity said illuminated display.

7. Scale according to one of the preceding claims, characterized in that it comprises at least two lamps (6,10) of different colors or at least one lamp that can light up at least two different colors.

8. Scale according to one of the preceding claims, characterized in that said lamp or lamps are LED (7,8,9).

9. Scale according to one of the preceding claims, characterized in that said lamps (6) are mounted on a support (21) disposed under the plate (2) so as to emit light towards a reflector ( 23) looking at the tray (2).

10. Scale according to claim 9, characterized in that said support (21) is arranged in the center of the plate (2).

11. Scale according to one of claims 9 or 10, characterized in that the area (3) illuminated tray (2) is made of an opal glass.

12. Scale according to one of the preceding claims, characterized in that the surface of said illuminated area (3) is substantially equal to the surface of the plate (2).

13. Scale according to one of claims 1 to 3, characterized in that it comprises a plurality of light areas distributed substantially over the entire surface of the tray.

14. Scale according to claim 13, characterized in that it comprises a bundle of optical fibers (29).

15. Scale according to claim 1, characterized in that said lamps are electroluminescent lamps (14,15,16).

16. Scale according to claim 15, characterized in that said electroluminescent lamps (14,15,16) are adjacent to each other.

17. Scale according to one of the preceding claims, characterized in that said previous value is an average of the weight calculated on the basis of several previous measurements.

18. Scale according to one of the preceding claims, characterized in that it comprises a digital display (11) measured values and a button (12) for switching on said display.