FIELD OF THE INVENTION

The present invention relates to mechanical or electromechanical pushbuttons, and more specifically a mechanical or electromechanical pushbutton with remote operation.

DESCRIPTION OF THE PRIOR ART

Traditional mechanical or electromechanical pushbuttons have a pushbutton body having an actuation area exposed to interaction with a user. For actuation, they require a physical contact between a user’s finger or hand, or possibly an object in possession of the user, and the actuation area of the pushbutton, which typically coincides with the whole surface thereof.

This contact can be a vector of contagion between various users which operate on the pushbutton. This drawback is particularly critical when the pushbuttons are installed on devices or machines which involve an interaction with a large number of users, such as for example the pushbutton panels of public elevators or automatic distributors/dispensers.

Although there exist various technologies which enable realising a pushbutton with touch-actuation, such as for example touch-devices known as “touch-screens”, these cannot be used in public services, as it is necessary always to provide, in parallel to an actuation mode that is contact-free or with touch-actuation, an actuation mode with a mechanical-type contact, such as for example a movement of the pushbutton itself, which enables partially-sighted persons to use the pushbuttons.

There exist various alternative technologies but each of them has special characteristics which become defects that prevent use thereof in determined applicational situations.

For example, actuation devices using pedalboards have been devised, but this is certainly an unwieldy and expensive solution as it includes the connecting-up of pushbuttons positioned remotely from the position of conventional pushbuttons, and therefore the laying of appropriate electrical connections. Especially in the case of adaptation of pre-existing plants, this solution requires making considerable modifications to the plant and leads to significant installation costs. Further, this solution is limited to a small number of pushbuttons as, given the greater dimensions, a large number of pushbuttons would make a pedalboard bulky and its use awkward.

Another proposal has been to actuate pushbuttons by means of voice recognition. This solution includes the combination of a conventional pushbutton panel with an acoustic recognition system which enables voice actuation. The disadvantage of this solution is the cost of realisation, as its actuation requires a significant additional calculation capacity since the operation of voice recognition is a complex operation in comparison with a mechanical actuation device. Further, this solution has reliability issues in noisy environments and in public places where there is access to users speaking different languages, with different dialects and accents (consider for example the heterogeneous nature of people who might access an elevator installed in an airport).

A mechanical pushbutton with a capacitive sensor can be realised for the application of a capacitive membrane on the actuation area of a mechanical button. This enables recognition of the presence of the hand or finger of a user at a distance of a few millimetres from the pushbutton. The main drawback of this solution, beyond the fact of not being able to recognise remote actions when gloves are worn, is that the distance necessary for the recognition is very close, thus increasing the probability that the user, in any case, touches the pushbutton in attempting to actuate it.

Recently pushbuttons have been devised the actuation of which is based on the detecting of an optic radiation, reflected or emitted. This solution includes the inserting of a LED or IR emitter and of a corresponding radiation detector flanked to the pushbutton, so that the reflection on the hand or finger of the user of the optic radiation emitted enables the pushbutton to be actuated. One of the main drawbacks of the solution is that the emission of optic radiation from a source leads to a further consumption of power which there would not be with “passive” technologies. Further, spurious reflections induced by diffusing means present in the ambient or worn by the user might induce undesired actuations of the pushbutton. A further drawback of this solution relates to variations of pigmentation of the complexion of the user or the use of gloves, which can lead to the impossibility of recognition of the remote action.

WO 2012/151417 describes a method for detecting gestures using a photosensor, in particular for detecting a movement of an object such as a hand or a finger with respect to the photosensor without contact therewith, for example for applications with a touch-screen or a mechanical pushbutton. In an embodiment the ambient light is detected as well as a decrease in the light on passage of the object on the photosensor (shading of the photosensor).

An approach of this sort necessarily requires being able to distinguish intention of the actuation command of a pushbutton by a user from a random phenomenon (shading event), which can easily occur in a neared arrangement of the pushbuttons, for example in a pushbutton panel of an intercom or an elevator. In fact, in an ambient with previously unknown illumination and frequented by a larger number of people moving in the space in front of a pushbutton, multiple shading events can take place on the pushbutton, involuntary and not predictable, which should not cause undesired actuations of the pushbutton.

SUMMARY OF THE INVENTION

The present invention has the aim of being able to provide a satisfactory solution to the drawbacks set out in the foregoing, thus avoiding the disadvantages of the known art. Specifically, the aim of the invention is to provide a solution that incorporates, in a mechanically-actuated pushbutton a remote operation function, that is economical, sturdy and efficient.

In the present invention this aim is attained with a mechanical pushbutton having the characteristics set out in claim 1 .

Particular modes of embodiment form the object of the dependent claims, the content of which is to be considered as an integral part of the present description.

A further object of the invention relates to a control system, comprising a mechanical or electromechanical pushbutton with remote operation, a pushbutton panel, comprising a plurality of remote-operated mechanical or electromechanical pushbuttons and a method for remote operation of a mechanical or electromechanical pushbutton as claimed.

In brief, the present invention is based on the use of photo-active devices able to detect a variation in light caused by the movement of an opaque body in proximity of the pushbutton and of a method able to identify a specific actuation gesture and exclude other undesired or incorrect gestures. The “touch-less” actuation mode is actuated by detecting the shadow projected on the pushbutton by the hand or finger of a user or operator. The solution according to the invention is not only based on the detection of a shadow in proximity of a pushbutton, but also on other characteristics such as duration, position and direction of the motion. This information is used to recognise the different shadows that can be projected on a pushbutton and to distinguish the shading events due to a desired action by the user from undesired events caused by other situations and which must not trigger an actuation of the pushbutton.

The present invention constitutes an improvement of a mechanically-actuated pushbutton due to the addition of the possibility of actuation with no contact. This additional function does not in any way alter the normal functioning of the pushbutton or its physical shape, but offers the possibility of choosing whether to actuate the pushbutton in the traditional way or whether by a gesture of the hand in proximity of the pushbutton (“touch-less mode).

The characteristic of the solution of the present invention of not altering the traditional mechanical actuation function of the pushbutton is a particularly significant aspect to enable, in public installations that must be accessible to partially-sighted persons, both an actuation of the pushbutton by physical contact and a tactile event perceptible by the user, such as for example the movement of the pushbutton.

Advantageously, as this is an additional technical function of a traditional mechanical or electromechanical pushbutton, which does not alter the normal mechanical operation of the pushbutton, but incorporates it by adding an alternative mode of remote actuation, since it does not require the replacement of the pushbutton or of a pushbutton panel bearing a plurality of pushbuttons, nor electronic cards which control the pushbutton panel and/or the plant associated thereto, the invention is substantially invisible to pre-existing mechanical or electromechanical actuation systems, as it directly interfaces with electronic management systems of actuation of the plant controlled by the pushbutton, and is actuable at low cost.

The invention advantageously enables a user to select the actuation method of the pushbutton according to needs or preference.

In brief, therefore, the invention has the following advantages:

- functional: it requires a minimum modification with respect to a mechanical or electromechanical pushbutton, so that it is possible to retrofit an existing pushbutton panel, only with a modification of the hardware and the firmware of the electronic control board of the pushbutton and the addition of a photovoltaic film, which can be extremely slim, for example having a thickness of less than 0.3 mm and a dimension that does not exceed by a centimetre the external edge of the mechanical pushbutton;

- economical: it does not require the addition of other electronic functions in the control architecture of the pushbutton panel, differently, for example, to the realisation of a voice recognition system which requires a significant increase in the computational capacity needed;

- operational: it is sturdy in that the only condition necessary for the functioning of the system relates to being able to operate in an illuminated ambient (>100 lux), a condition more than acceptable given that by definition operating on a pushbutton panel requires a minimum light level in order to see and identify the pushbuttons. BRIEF DESCRIPTION OF THE DRAWINGS

Further characteristics and advantages of the invention will be set out more fully in the detailed description that follows of an embodiment thereof, given by way of non-limiting example, with reference to the accompanying drawings, in which: figure 1 is a schematic representation of a pushbutton panel in an ambient; figure 2 is a schematic representation of a pushbutton provided with a predefined recognition region of a predefined remote actuation recognition region associated with the pushbutton and a diagram of the signals emitted by the photodetector means arranged in the region in the illustrated condition of shading of the pushbutton by a finger or a hand of a user; figures 3a, 3b and 3c are respective schematic illustrations of a pushbutton provided with a predefined recognition region of a remote operation wherein the photodetector means comprise a first and a second detection area, and respective diagrams of the signal emitted by the photodetector means, in different conditions of shading of the pushbutton by a finger or a hand of a user; figures 4a-4d show variants of realisation of the detection areas of the photodetector means coupled to the actuation area of the pushbutton or in proximity thereto; figure 5 illustrates a remote operation condition of a pushbutton and the relative condition of shading on adjacent pushbuttons; and figures 6a and 6b are schematic views respectively in plan view and transversal section of a constructional embodiment of a pushbutton according to the invention. DESCRIPTION OF THE PREFERRED EMBODIMENTS

In the figures, elements or components that are identical or functionally equivalent are denoted using the same references.

Figure 1 shows a pushbutton panel (P), for example a pushbutton panel of an elevator or of a dispenser/automatic dispenser apparatus (not illustrated), comprising a plurality of pushbuttons (B), for example mechanical or electromechanical pushbuttons, aligned or arranged in a matrix and coupled to a support panel (L) from which it emerges or is accessible, i.e. exposed to interaction with a user, at least a part of the pushbutton body, and in particular an actuation area thereof. The pushbuttons (B) can preferably be back-lit or sources of illumination (L1 , L2) can be provided at the top of the panel (L) that are predisposed to emit a localized light emitting means according to a direction of illumination coplanar to the surface of the panel (L) and to the actuation area of the pushbutton body.

The letter (S) denotes an ambient light source, the arrangement of which in the ambient in which the pushbutton panel (P) is located determines the projection of shadows on the pushbutton panel when an opaque body is interposed between the ambient light source and the pushbutton panel.

Figure 2 illustrates, on the left-side image, a generic pushbutton (B) having an actuation area (A) to the external periphery of which is associated a ring nut (F) on which a recognition region (R) of a remote operation of the pushbutton is formed. The region (R) comprises a photo-detector device for detecting the intensity of the ambient light incident on the region (R) and for emitting a signal, for example a voltage signal, indicative of the intensity of incident ambient light over time.

The right-side image shows, on the other hand, the trend over time of a voltage signal (V) emitted by the photo-detector device, in which a change can be observed in the voltage value generated by the photo-detector device induced by a shading event (E) on the recognition region (R) of a remote operation, for example by effect of the passage of a finger of a user’s hand in proximity of the pushbutton.

In general, the possibility of recognising the projection of a shadow on the pushbutton, and of detecting a variation in the intensity of the ambient light coming from the source (S) and incident on the pushbutton, is given by the presence of a photo-detector device. According to the invention, photodetector means are advantageously predisposed that include at least a first detection area and at least a second detection area, each comprising at least a respective photovoltaic cell or photosensor able to convert the variation in illumination detected into a voltage value measurable by processing means (C), for example installed on-board an electronic control board associated to the pushbutton or the pushbutton panel the cabling or wireless electrical connection of which with the single pushbuttons is illustrated in figure 1 by the double-arrow.

The photodetector means have a shape that is such as to be able to accommodate the photovoltaic cells or photosensors on the surface of the pushbutton body constituting the actuation area thereof, or externally thereof, but in the immediate vicinity, for example concentrically to at least a part of the peripheral profile of the pushbutton in such a way that a shadow projected onto the pushbutton can obscure at least a photovoltaic cell or photosensors of the photodetector means.

Each photovoltaic cell or photosensor is able to detect the intensity of the incident ambient light caused by a shading event and, according to the value thereof, it is possible to distinguish between shadows generated by opaque bodies located in close proximity thereto and shadows generated by opaque bodies located distantly thereto. This ability to discriminate is due to the ability of each photovoltaic cell or photosensor to generate the electric signal, in the form of voltage or current, the amplitude of which is inversely proportional to the intensity of the shading.

In this way it is possible for the processing means (C) to recognise a decrease in the intensity of incident ambient light for at least a predetermined actuation time interval on said first and second detection areas, comparing the decrease in ambient light intensity with a reference ambient light intensity decrease threshold, and judging an actuation of the pushbutton as a consequence of a decrease in the intensity of ambient light greater than said reference threshold in only one of said detection areas, and judging an absence of actuation of the pushbutton as a consequence of a decrease in ambient light intensity greater than said reference threshold in both the detection areas.

The decrease in the reference ambient light intensity decrease threshold is advantageously set in such a way as to discriminate valid shading events, as they are determined by the movement of an opaque body in proximity of the pushbutton, i.e. at a smaller distance than a present threshold distance, from shading events that are non-valid, as they correspond to a movement that took place at a distance from the pushbutton, and therefore are probably not associated to the intention of a user to select the pushbutton.

Alternatively it is possible to identify two levels of ambient light intensity threshold so that only intermediate shading values can be recognised as valid. For example, in this way undesired actuations could be eliminated, caused by contact with a body with the mechanical pushbutton, which determines a total shading event recognisable by the exceeding of a second ambient light intensity threshold near to absence of illumination. A significant example of application where this detail is important is given by the use of a pushbutton panel by a partially-sighted person who has to read the Braille characters positioned on the pushbuttons, which will lead to her or his having first to touch all of the pushbuttons with no intention of actuating them, but in order to select the desired pushbutton.

According to the invention, each photovoltaic cell or photosensor is advantageously designed in such a way as to respond to the variation of illumination with a variation in the electric signal in a time comparable to the movement of a user’s hand placed in proximity of the pushbutton. In this way, on the basis of the duration of a shading event, the processing means (C) can exclude non-valid movements as being too rapid or too slow. For example, a person resting his or her body on a pushbutton will cause a prolonged shading event which might be regarded as non-valid, and thus does not actuate the pushbutton.

Figures 3a-3c illustrate possible arrangements of detection areas of the photodetector means, each of which comprises for example, a respective photodetector device, such as a photovoltaic cell or photosensor, and possible combinations of voltage signals emitted by the detecting devices.

In figure 3a, the detection areas (Z1 , Z2) with the respective photodetector devices are arranged in opposite space regions with respect to the centroid of the pushbutton (B), respectively lower and higher with respect to the centroid of the pushbutton (B). The diagram on the left shows the trend of the voltage signals (V1 , V2) over time depending on a shading event (E) on only the detection areas (Z1), for example by effect of the movement from the left towards the right, from the bottom upwards of a user’s finger on the actuation area of the pushbutton, which stops with the tip of the finger at the centre of the actuation area of the pushbutton. The combination of these signals is considered a valid actuation command of the pushbutton. The diagram on the right shows the trend of the voltage signals (V1 , V2) over time depending on a shading event (E) at the same time in both detection areas (Z1 and Z2), for example by effect of the superposing of a user’s finger on the actuation area of the pushbutton, in which the finger covers, by extension, diametrically from left towards the right extension and from bottom upwards, the actuation area of the pushbutton. The combination of these signals is considered an absence of an actuation command of the pushbutton or a non-valid command.

In figure 3b, the detection areas (Z1 , Z2) with the respective photodetector devices are arranged in adjacent space regions arranged on the same side with respect to the centroid of the pushbutton (B). The diagram on the left shows the trend of the voltage signals (V1 , V2) over time depending on a shading event (E) which in successive moments involves both the detection areas (Z1 and Z2) by effect of the movement of a user’s finger from the left towards the right on the actuation area of the pushbutton. The combination of these signals is considered a valid actuation command of the pushbutton. The central diagram shows the trend of the voltage signals (V1 , V2) over time depending on a shading event (E) which in successive moments involves both the detection areas (Z2 and Z1) by effect of the movement of a user’s finger from the right towards the left on the actuation area of the pushbutton. The combination of these signals is considered an absence of an actuation command of the pushbutton or a non-valid command. The diagram on the right shows the trend of the voltage signals (V1 , V2) over time depending on a shading event (E) at the same time in both detection areas (Z1 and Z2), for example by effect of the superposing of one or more of the user’s fingers on both the actuating areas of the pushbutton. The combination of these signals is considered an absence of an actuation command of the pushbutton or a non-valid command.

Figure 3c illustrates a combination of the arrangements of detection areas of figures 3a and 3b. Three detection areas (Z1 , Z2, Z3) with the respective photodetector devices are arranged in opposite space regions with respect to the centroid of the pushbutton (B), respectively the detection areas (Z1 , Z2) lower than and the detection area (Z3) higher than the centroid of the pushbutton, the detection areas (Z1 , Z2) being arranged adjacent on the same side with respect to the centroid of the pushbutton (B). The diagram on the left shows the trend of the voltage signals (V1 , V2, V3) over time depending on a shading event (E) on the detection areas (Z1 and Z2), the latter for a longer period of time, for example by effect of the movement from the left towards the right of one or more of the user’s fingers on the actuation area of the pushbutton, which stops with the tip of the finger or fingers at the centre of the actuation area of the pushbutton. The combination of these signals is considered a valid actuation command of the pushbutton. The central diagram shows the trend of the voltage signals (V1 , V2, V3) over time depending on a shading event (E) at the same time in both detection areas (Z1 and Z2), for example by effect of the superposing of one or more of the user’s fingers on both the actuating areas of the pushbutton. The combination of these signals is considered an absence of an actuation command of the pushbutton or a non-valid command. The diagram on the right shows the trend of the voltage signals (V1 , V2, V3) over time depending on a shading event (E) on all the detection areas (Z1 , Z2 and Z3), progressively over a longer period of time, for example by effect of the movement from the left towards the right of one or more of the user’s fingers on the actuation area of the pushbutton, in which the finger or fingers cover, by diametric extension, the actuation area of the pushbutton. The combination of these signals is considered an absence of an actuation command of the pushbutton or a non-valid command.

According to the invention the photodetector means include at least a first detection area and at least a second detection area arranged in opposite space regions relative to the centroid of the pushbutton. This arrangement is shown in figure 4a, where the photodetector means are peripherally coupled to the actuation area (A) of the pushbutton body (B) to detect the intensity of the ambient light incident on a recognition region (R) of remote operation of the pushbutton, circumferential to the pushbutton. In figures 4a and 4b the plurality of photovoltaic cells or photosensors making up the photodetector means is constituted by two sub-assemblies of cells or photosensors positioned respectively in a space region (R1 ) that is lower than the centroid of the mechanical pushbutton and in a space region (R2) that is higher than the centroid of the mechanical pushbutton. The limit case of figure 4a includes a single photovoltaic cell or photosensor belonging to a first detection area (Z1) in the space region (R1 ) and a single photovoltaic cell or photosensor belonging to a second detection area (Z2) in the space region (R2).

Optionally, the photodetector means comprise at least a third detection area (Z3) not aligned to the first and second detection area, arranged in the space region of the first or second detection area, or in a space region that is lateral with respect to the centroid of the mechanical pushbutton, with the aim of improving the gestural recognition as described in the following.

Figure 4b illustrates an embodiment wherein the photodetector means comprise a photovoltaic cell or photosensor belonging to a first detection area (ZT) and a photovoltaic cell or photosensor belonging to a third detection area (Z1”) in the space region (R1 ), as well as a photovoltaic cell or photosensor belonging to a second detection area (Z2’) and a photovoltaic cell or photosensor belonging to a fourth detection area (Z2”) in the space region (R2).

Figure 4c illustrates an embodiment wherein the photodetector means comprise a photovoltaic cell or photosensor belonging to a first detection area (Z1) in the space region (R1 ), a photovoltaic cell or photosensor belonging to a second detection area (Z2) in the space region (R2), as well as a pair of photovoltaic cells or photosensors belonging respectively to a third detection area (Z3) and to a fourth detection area (Z4”), both external of the space regions (R1) and (R2).

Lastly, figure 4d illustrates an embodiment wherein the photodetector means comprise a photovoltaic cell or photosensor belonging to a first detection area (Z1) in the space region (R1 ), a photovoltaic cell or photosensor belonging to a second detection area (Z2) in the space region (R2), and a third photovoltaic cell or photosensor belonging to a third detection area (Z3) in the space region (R1 ).

In the most typical situation the illumination of a space, whether by sunshine or artificial, comes from above; additionally, a user typically acts on a pushbutton panel with her or his elbow facing downwards. Therefore the shadow that the operator projects on a usually-vertical pushbutton panel surface extends downwards starting from the position of the shadow of the hand. In this way it is possible to distinguish whether the projected shadow has the vertex centred on the pushbutton, and the operator’s hand in proximity thereof shades only the cell or lower photosensor (or the assembly of cells or photosensors) and not the upper, or whether the shadow has the vertex thereof positioned higher, and the operator’s hand is centred on an upper pushbutton and for this reason the shadow is cast on both the cells or photosensors, or whether the shadow has the vertex thereof positioned lower and the operator’s hand is centred on the lower pushbutton and does not obscure any cell or photosensor. In this way it is possible to distinguish the three different cases and recognise a desired actuation while excluding undesired actuations.

For example, the shadow created by an operator during the actuation of a pushbutton on a pushbutton panel made up of various pushbuttons can lead to shadows on several pushbuttons, the actuation of which can be excluded following the described method.

In general, a plurality of photodetector devices associated to a pushbutton can enable recognition of the shape and movement of a shadow projected on the pushbutton and can therefore indicate whether this corresponds to a valid actuation command of the pushbutton or not.

In general, according to the invention, the discrimination of shading events on the single photodetector devices is done by measuring the duration of the shading event so as to verify whether the event is compatible with predetermined pushbutton actuation rules. The discrimination of the shading events on the photodetector means of a single pushbutton takes place by combination of the shading information supplied by all the photovoltaic cells or photosensors that are part thereof, which enable recognition of a specific shading shape. Further, the detection of the relative times between the start or end fronts of a shading event on different cells or photosensors enable identification of the movement of the shadow on the pushbutton and consequently recognition or exclusion of movements considered correct or not.

Figures 4a-4d illustrate examples of possible embodiments of the invention based on different configurations of the photodetector means.

When all the photovoltaic cells or photosensors that are part of the space region (R1) (lower than the centroid of the pushbutton) and none of the photovoltaic cells or photosensors that are part of the higher space region (R2) are shaded, the actuation command of the pushbutton is recognised as valid. The additional photovoltaic cells or photosensors can be used to discriminate the movement of the shadow and insert further filters on the movement that has taken place. The additional cells or photosensors can be part of the lower and higher space regions, as in figures 4b and 4d, or not, as in figure 4c.

An embodiment of the invention that includes the presence of at least two photovoltaic cells or photosensors positioned flanked to one another, which are part of the lower or higher space region or not, enables distinguishing the movement of the shadow as one of the two cells or photosensors will be obscured (or illuminated) before the other during the horizontal movement of a user’s hand. In this way, it will be possible to distinguish a movement from right towards the left from the opposite movement and therefore to exclude the undesired actuations if considered to be non-conforming.

In general terms a plurality of photovoltaic cells or photosensors positioned about a pushbutton can enable recognition of direction and sense of movement of a shadow projected there and can therefore indicate whether these are correct for the purpose of valid actuation of the pushbutton or not.

Figure 5 illustrates an example of functioning of the system on a pushbutton panel (P) comprising three pushbuttons (B1 , B2, B3) aligned in a column, wherein the photodetector means have a configuration as illustrated in figure 4d, with three detection areas (Z1 , Z2 and Z3) being arranged in a triangle about the centroid of the pushbutton (B). The position of the user’s hand and finger indicate the desire to select the actuation of the central pushbutton (B2).

The control system of the invention, comprising a mechanical or electromechanical pushbutton with remote operation according to the embodiments described herein, enables recognition of the non-shaded condition of all the photodetector devices of the pushbutton (B1 ) and the totally-shaded condition of all the photodetector devices of the pushbutton (B3), interpreting them as conditions of absence of actuation of the pushbutton, respectively, in the first case because no detection was made of a decrease in the intensity of ambient light greater than a predetermined reference threshold, and in the second case because a decrease in the intensity of ambient light is detected that is greater than the predetermined reference threshold in all the detection areas.

Likewise, the invention is applicable in a pushbutton panel comprising a plurality of pushbuttons arranged in flanked columns. In this case an actuating gesture of a single pushbutton which simply includes the nearing of the hand might easily cause involuntary actuations of other bordering pushbuttons because the shadow of the arm projected diagonally, by effect of a non-vertical illumination of the pushbutton panel, might extend to the pushbuttons of a flanked column. A more robust actuating gesture is when the hand is neared to and then moved from the pushbutton with a lateral motion (towards the right or left, according to the recognition rules adopted by the processing means). In this way it is difficult for a spurious signal to cause undesired actuations on border pushbuttons as the pushbuttons would be subjected to a shading event with a movement in a different direction, or at different times, or which intercepts, during the movement, the space region higher than the centroid of the pushbutton. A lateral motion of a shading is recognised owing to the signals emitted by the flanked photodetector devices and the field of the possible gestures of the pushbutton is made more selective.

An advantageous embodiment of the invention is the one illustrated in figure 4c in which the number of photodetector devices (photovoltaic cells or photosensors) is in a number greater than three, of which at least one is positioned above the centroid of the pushbutton and at least one is positioned below the centroid of the pushbutton, and of which at least two are positioned in a flanked configuration. This arrangement enables recognition of both the position of a shadow and the movement thereof and, therefore, application of sophisticated rules for the recognition of the correct actuating gesture of the pushbutton.

Each photo-detector device can comprise a plurality of photovoltaic cells or photosensors, between two and about ten cells or photosensors. In particular, in its simplest form, two or three photovoltaic cells or photosensors are sufficient to realise the functions described herein. The use of a greater number of photovoltaic cells or photosensors enables:

- making the detection of an actuation condition of a pushbutton or using redundant signals more robust;

- better identifying the shadows to be selected by positioning cells or photosensors in specific positions where there is a greater probability of passage (or not) of the shadows;

- better positioning the cells or photosensors above or about the mechanical pushbutton, in consideration of the constraints of space created by the shape of the pushbuttons or elements positioned on the surface of the pushbutton panel.

With regard to the latter aspect, a problem that can be encountered on pushbutton panels comprising several pushbuttons is given by the positioning thereof aligned vertically or in one or more columns, so that the lower edge of a pushbutton and the upper edge of the adjacent pushbutton are very near one another, or two pushbuttons of adjacent columns are flanked in proximity. If the photodetector means are arranged externally of the profile of the mechanical pushbutton there will therefore be a difficulty in finding sufficient space in the zones where the adjacent pushbuttons are near (along the vertical and horizontal alignment directions). Therefore, the simplest and most obvious solution, i.e. the one in which two photodetector devices (photovoltaic cells or photosensors) are positioned respectively above and below the pushbutton and aligned on the vertical, is not necessarily the best. In fact in this way the photodetector devices would be positioned at the point where the available space is the worst. In order to obviate this problem co-locations of the photodetector devices can be exploited, as illustrated in figures 3a-3c.

Figures 6a and 6b illustrate a pushbutton which is an object of the invention in plan view and a view in transversal section to the plane of the pushbutton panel.

The pushbutton body (B) comprises a head (H) having the actuation area (A) exposed to interaction with a user, a threaded rod (T) which emerges from the head and is intended to be arranged through a mounting seat or through-hole (TH) formed in a support panel (L) of the pushbutton, a threaded ring nut (N) keyed on the rod (T) and adapted to fasten the pushbutton to the support panel.

The photodetector means are embedded in a substantially planar support film (SF) configured to be applied to the pushbutton in such a way as to at least partially cover the actuation area of the pushbutton body and/or an area adjacent to said actuation area. Figure 6b illustrates a support film (SF) which circumferentially surrounds the head of the pushbutton. The support film SF has at least one appendage formation SF' having electrically conductive connection tracks to the photodetector means, which extends along the rod (T) inside the ring nut (N) up to a support plate (not illustrated) of the processing means, with which said conductive tracks are electrically coupled.

The support film of the photodetector means is extremely slim, of the order of a millimetre or even less, and flexible. The electrical connection appendage of the photodetector means to the processing means is folded internally of the pushbutton in such a way as to require the lowest additional volume with respect to the pre-existing mechanical pushbutton structure. It is configured to bring the signals generated by the photodetector means, necessarily arranged on the external side (exposed) of the pushbutton panel towards the control electronics, positioned internally of the pushbutton panel on the back of the pushbutton, crossing the plane of the pushbutton panel.

The proposed solution for passage of the electrical connection appendage into the narrow gap between the mounting hole (TH) and the pushbutton (B) itself enables a cabling without passage of wires above the pushbutton panel and without having to make mechanical modifications (new holes or changes to those present).

A specific embodiment of the invention includes the manufacturing of the photodetector means with printing techniques on the plastic film. Differently to other photovoltaic technologies, printed photodetector devices enable realising slim photovoltaic films, which can therefore be incorporated in a pushbutton panel without altering the mechanical characteristics thereof to a significant extent. Further, this allows for freedom of shape both in the dimensioning of the single photovoltaic cells or photosensors and in the positioning thereof in relation to the position of the pushbutton and in relation to the reciprocal positioning of the cells or photosensors. In this way it is possible to study shape and position of the photovoltaic cells or photosensors in such a way that they can enable the best coupling with the shape and movement of the shadow projected onto the pushbutton and thus enable correct recognition thereof. This characteristic is particularly interesting if considering a pushbutton panel which might incorporate various pushbuttons and therefore it becomes very critical to recognise the movements that take place in proximity of each pushbutton and which might cause undesired actuations.

The dimensioning of the active area of the single cells or photosensors constituting the photodetector means must take account of two contrasting indications. On one hand it is desirable for the single cells or photosensors to have as large an area as possible so that at low illumination levels the electrical current generated thereby is as great as possible. Good current values are necessary to correctly pilot an electronic input so as to be able to overcome current leakage thereof and/or to charge, in sufficiently rapid times, the parasitic capacitance thereof. On the other hand, however, the surface of the cell or photosensor must be smaller than that of the body that generates the shadow, otherwise the shading would be partial. Considering the possibility that the actuation is effected by a finger, the optimal dimension of the cell or photosensor cannot exceed a diameter of more than 10mm. Therefore, to respond to these opposite constraints, the active area of the cell or photosensor must extend on a surface having a diameter comprised between a minimum of 1 mm and a maximum of 10mm.

In an improved embodiment, the pushbutton or pushbutton panel further comprises localized light emitting means according to a direction of illumination coplanar to the surface of the actuation area of the body of the pushbutton, i.e. to the surface of the pushbutton panel, and of the photodetector means, for example as indicated by L1 and L2 in figure 1 , so that the localized light does not directly strike the photodetector means.

The photodetector means are adapted to emit signals indicative of the intensity of localized light incident on each detection area over time, determined by the reflection on an opaque body in proximity of the pushbutton. The processing means are adapted to receive the signals indicative of the intensity of localized light incident on each detection area over time and are arranged for recognizing an increase in the intensity of incident localized light for at least a predetermined actuation time interval on at least one of the first and second detection areas, comparing the increase in localized light intensity with a reference threshold for an increase in the reference localized light intensity, and judging an actuation of the pushbutton as a consequence of an increase in localized light intensity greater than said reference threshold in only one of said first and second detection areas, and judging an absence of actuation of the pushbutton in the absence of an increase in localized light intensity greater than said reference threshold in both said first and second detection areas, or as a consequence of an increase in localized light intensity greater than said threshold reference in both said first and second detection areas.

The localized light emitting means are advantageously arranged to be activated when said processing means recognize a decrease in the intensity of incident ambient light for a predetermined actuation time interval on the first or second detection area.

The localized light emitting means are advantageously adapted to modulate over time the intensity of the localized light according to a predetermined modulation frequency of the pushbutton and the processing means are arranged to recognize an increase in the incident localized light intensity for a predetermined actuation time interval on at least one of the first and second detection areas when the signals indicative of the intensity of localized light incident over time on each detection area have the same modulation frequency. In this way it is possible to combine the information given by the reduction of ambient illumination caused by the proximity of a user’s hand or a finger to the pushbutton, with the increase of the localized and modulated light due to the reflection thereof on the hand or finger of the user towards the photodetector means, also caused by the proximity of the user’s hand or finger to the pushbutton.

Still more advantageously, respective localized modulated light emitting means are associated to the photodetector means of each pushbutton to communicate an identifying code of the pushbutton in question. In this way only the localized light coming from a determined pushbutton and reflected by the finger or hand of the user will be identified and this will provide an additional element in discerning the validity of the actuating gesture.

This additional characteristic is advantageous when the pushbutton is housed in a dark ambience or one having poor lighting, where it would be difficult to distinguish a reduction of the intensity of the ambient illumination due to a shading caused by a body in proximity of the pushbutton by a decrease in intensity of ambient illumination due to a shading caused by the movement of a body at a distance. This is because with a poor ambient illumination the variation in intensity of shading is less marked.

By way of further improving the invention, it is preferable for the processing means to carry out a filter action of the optical signals frequency received by the photodetector means, in order to eliminate the effect of known periodic fluctuations in the light source which are not to be taken into consideration. A relevant example is the electricity network frequency filter: the indoor sources of illumination supplied in alternating current are not constant, but are modulated with a frequency of 50 Hertz (or 60 Hertz), or whole multiples. This can be obtained with an analog or digital filter with a filtering time of 20 milliseconds (or 17 milliseconds) or whole fractions.

In other situations it might be necessary to filter different frequencies if they periodically influence the lighting of the pushbutton.

A second relevant case of filtering is the one necessary for excluding the effect of any light sources that might be present on the pushbutton, which can be read by the photovoltaic cells or photosensors via reflection on objects close to the pushbutton itself. This reflection effect might be useful for the purpose of recognition or correct actuation (as indicated above) but at the same time might also alter the lighting value that otherwise would have been lower. This is a significant situation as very often the pushbuttons are equipped with LED lights which can provide a lighting reference to the user, for example one indicating that the pushbutton has been actuated. A possible example of filtering is that of modulating the light emitted by the pushbutton in a known way and acquiring samples of the electric signal supplied by the cell or photosensor only at times in which it is known that the LEDs are switched off.

An opposite case of filtering might instead be one in which it is desired to detect a reflected light which has a frequency modulation and only this is to be recognised in a background of constant illumination or one modulated at different frequencies. In this case too the processing means must filter the overall signal received from the photodetector means in order to read the modulated signal and eliminate the non-modulated signal.

A further advantageous embodiment of the invention includes the predisposing of the processing means for determining the reference ambient light intensity decrease threshold as a function of the current ambient light intensity value. This is because the ambient light incident on a pushbutton can significantly change over the various times of day, for example due to the atmospheric conditions in an outdoor ambient or by effect of the daily evolution of the natural light, or its alternating with an artificial light. A further relevant case is the shadow that the body of the user might cause on a pushbutton panel by nearing it. To correctly recognise a shadow that might have different intensities according to the background light, it is necessary to measure the background light intensity, memorise that value and use it as a reference for comparing light variations corresponding to shading. In other words, the recognition of the shading must not be done by observing an absolute value, but the relative variation with respect to the condition of background illumination condition. Therefore, the current value of the electric signal provided by a photo-detector device must always be compared to the present mean value, corresponding to the background value, and only when the first is lower than a preset fraction of the second can a shading be correctly identified. As a consequence this mechanism enables filtering variations of the electric signal that are too slow as these would be compared with a measured mean value that is identical to the current value.

Lastly, the invention has as an objective a computer program, in particular a computer program on or in support of information or memory, adapted for actuating a method for remote actuation of a mechanical or electromechanical pushbutton having a pushbutton body including an actuation area exposed to interaction with a user, the method comprising the operations of:

- detecting the intensity of the ambient light incident on a predefined remote actuation recognition region associated with the actuation area of the pushbutton body, including at least one first detection area and at least one second detection area arranged in opposite space regions relative to the centroid of the pushbutton;

- recognizing a decrease in said intensity of incident ambient light for at least a predetermined actuation time interval on said first and second detection areas; - comparing said decrease in ambient light intensity with a reference ambient light intensity decrease threshold; and

- judging an actuation of the pushbutton as a consequence of a decrease in the intensity of ambient light greater than said reference threshold in only one of said detection areas, and judging an absence of actuation of the pushbutton as a consequence of a decrease in ambient light intensity greater than said reference threshold in both said detection areas.

Naturally, with no effect on the principle of the invention, the embodiments and the details of the embodiment might be broadly varied with respect to what has been described and illustrated purely by way of non-limiting example, without thus forsaking the scope of protection of the invention defined in the appended claims.