Abstract:
The invention relates to an interface device including an array of pixels and an insulating, transparent substrate, the pixels being connected to the substrate by linking elements, the contact surface between the linking elements and the pixels being strictly smaller than the surface of the pixels facing the substrate.

Description:
BACKGROUND 
       [0001]    The present invention relates to a user interface device, or man-machine interface, having transparent electrodes. 
       DISCUSSION OF THE RELATED ART 
       [0002]    There are several examples of user interface or man-machine interface devices with transparent electrodes. For example, certain display screens, particularly liquid crystal displays and plasma displays, comprise transparent electrodes. Such is also the case of touch-sensitive displays which comprise a touch-sensitive surface, that is, a user interface device controllable by simple sliding of a finger or of a hand on a touch-sensitive surface, superimposed on a display screen. 
         [0003]    Another example relates to a contactless user interface device such as described in French patent application FR1158607. 
         [0004]    A user interface device having transparent electrodes generally comprises a pixel array. “Pixel” means a photoactive element, that is, an element capable, in particular, of emitting light, of modifying the light crossing it, and/or of detecting the light that it receives. As an example, the pixel may be a photon sensor. The selection of a pixel is performed by two electrodes which sandwich the pixel. The photons should be able to propagate freely between a user and the pixels. For this purpose, the electrodes connected to the pixels located between the pixels and the user are made of a transparent material. The transparent electrodes for example have the shape of strips connected to a plurality of pixels or of a single film connected to all the array pixels. The transparent electrodes are generally covered with an insulating and transparent coating, for example, plastic or glass. 
         [0005]    The materials used to form transparent electrodes which are the most satisfactory in terms of properties of electric conductivity and transparency are transparent conductive oxides or TCOs, for example, indium tin oxide or ITO. To obtain a satisfactory electric conduction of the transparent electrodes, the thickness of the layers of the TCO material used should be greater than 50 nm. However, the layers of TCO material thus formed are brittle. Indeed, the forming of cracks in the electrodes can be observed when they are submitted to excessive stress. This may occur on manufacturing of the user interface device, which may in particular comprise thermal anneal steps which create stress in the layers of TCO material. This may also occur when the user interface device is desired to be deformed in operation, for example, when the user interface device is desired to be applied on a non-planar surface. 
         [0006]    Attempts have been made to replace the TCO material with a more flexible material. A possibility corresponds to using a conductive polymer. However, the properties of electric conductivity of currently-available conductive polymers are generally not as good as those of TCO materials. Another possibility corresponds to using metals to form the electrodes. However, it is then necessary to deposit very thin metal layers, for example thinner than 10 nm for gold, to obtain transparent electrodes. The deposition methods are then complex. Another possibility comprises replacing the transparent electrodes with nanometer-range metal wires or of forming the transparent electrodes with carbon nanotubes. However, methods of manufacturing such electrodes are complex and/or cannot for the time being be implemented at a low cost. 
         [0007]    More generally, the problems described hereabove for layers of TCO material may also be encountered as soon as the pixels comprise at least one layer of a brittle material. 
         [0008]    There thus is a need for a user interface device comprising layers of a brittle material, particularly a user interface comprising transparent electrodes made of TCO, which do not crack on manufacturing of the user interface device or when the user interface device is deformed in operation. 
       SUMMARY 
       [0009]    Thus, an object of the present invention is to provide a user interface device overcoming at least some of the disadvantages of existing devices. 
         [0010]    Another object of the present invention is to provide a user interface device comprising at least one layer of a brittle material, particularly a user interface device having transparent electrodes made of TCO material. 
         [0011]    Another object of the present invention is to provide a user interface device capable of being deformed in operation. 
         [0012]    Another object of an embodiment of the present invention is to provide a user interface device capable of being actuated without any contact with the user. 
         [0013]    Another object of an embodiment of the present invention is to provide a contactless user interface device capable of operating without emitting any radiation. 
         [0014]    The present invention provides an interface device comprising a pixel array and a transparent insulating substrate, the pixels being connected to the substrate by connection elements, the contact surface area between the connection elements and the pixels being smaller than the surface area of the pixels opposite the substrate. 
         [0015]    According to an embodiment of the invention, the contact surface area between the connection elements and the pixels is smaller than half the surface area of the electrodes opposite the substrate. 
         [0016]    According to an embodiment of the invention, the connection elements are made of a material more flexible than the materials forming the pixels. 
         [0017]    According to an embodiment of the invention, the connection elements are made of a flexible material having an elongation at break greater than or equal to 100. 
         [0018]    According to an embodiment of the invention, the pixels comprise transparent conductive electrodes, the connection elements being connected to the electrodes, the contact surface area between the connection elements and the electrodes being smaller than the surface area of the electrodes opposite the substrate. 
         [0019]    According to an embodiment of the invention, the electrodes are made of transparent conductive oxide. 
         [0020]    According to an embodiment of the invention, the transparent conductive oxide is indium tin oxide or gallium zinc oxide. 
         [0021]    According to an embodiment of the invention, the connection elements comprise at least a resist. 
         [0022]    According to an embodiment of the invention, the connection elements further comprise at least an elastomer. 
         [0023]    According to an embodiment of the invention, the connection elements are electrically conductive. 
         [0024]    According to an embodiment of the invention, the pixels are organic photon sensors. 
         [0025]    According to an embodiment of the invention, the device further comprises conductive elements on the substrate partly extending between the electrodes and the substrate, where the electrodes are not in contact with the conductive elements when the device is not deformed. 
         [0026]    According to an embodiment of the invention, the conductive elements are metallic or made of conductive polymer. 
         [0027]    The present invention also provides a method of manufacturing an interface device such as defined hereabove, comprising the steps of: 
         [0028]    (a) covering the transparent insulating substrate with a resist layer; 
         [0029]    (b) exposing the resist layer to a radiation to define the connection elements; 
         [0030]    (c) forming the pixels on the resist layer; and 
         [0031]    (d) before or after step (c), partially removing the resist layer to form the connection elements. 
         [0032]    According to an embodiment of the invention, step (c) comprises covering the resist layer with an electrically-conductive transparent layer and etching the electrically-conductive transparent layer to form the electrodes. 
         [0033]    According to an embodiment of the invention, the electrically-conductive transparent layer is made of transparent conductive oxide. 
         [0034]    According to an embodiment of the invention, the pixels are formed by successive deposition of additional layers on the electrically-conductive transparent layer and etching said additional layers. 
         [0035]    According to an embodiment of the invention, the pixels are formed by printing techniques on the electrodes. 
         [0036]    According to an embodiment of the invention, the method further comprises forming conductive elements on the substrate and covering the substrate and the conductive elements with the resist layer. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0037]    The foregoing and other features and advantages will be discussed in detail in the following non-limiting description of specific embodiments in connection with the accompanying drawings, among which: 
           [0038]      FIG. 1  is a partial simplified cross-section view of an example of a known user interface device having transparent electrodes; 
           [0039]      FIGS. 2 and 3  are partial simplified cross-section views of an embodiment of the user interface device according to the invention; 
           [0040]      FIGS. 4 to 7  are partial simplified views of embodiments of a connection element of the interface device of  FIG. 2 ; 
           [0041]      FIG. 8  is a partial simplified cross-section view of another embodiment of the user interface device; 
           [0042]      FIGS. 9 and 10  are partial simplified cross-section views of another embodiment of the user interface device; 
           [0043]      FIG. 11  is a cross-section view similar to  FIG. 9  and shows the user interface device in a deformed state; 
           [0044]      FIGS. 12A to 12G  are partial simplified cross-section views of the structures obtained a successive steps of an embodiment of a method of manufacturing the user interface device shown in  FIG. 9 ; and 
           [0045]      FIGS. 13A to 13G  are partial simplified cross-section views of the structures obtained at successive steps of another embodiment of a method of manufacturing the user interface device shown in  FIG. 9 . 
       
    
    
     DETAILED DESCRIPTION 
       [0046]    For clarity, the same elements have been designated with the same reference numerals in the various drawings and, further, the various drawings are not to scale. Further, only those elements which are useful to the understanding of the present invention have been shown and will be described. In particular, what use is made of the user interface devices described hereafter has not been detailed. It will be within the abilities of those skilled in the art to use the provided devices in any type of system capable of being controlled via a touch and/or contactless interface. Further, the means for processing the information provided by the user interface devices described hereafter and the means of connection with the system(s) to be controlled are within the abilities of those skilled in the art and will not be described. 
         [0047]      FIG. 1  shows an example of a contactless user interface device such as described in French patent application FR1158607. 
         [0048]    Device  10  comprises an array of photon sensors or photodetectors  12 , preferably capable of detecting variations of the shadow or of the image of an actuating member, for example, a finger  14 . Photodetectors  12  may be arranged in rows and in columns. Photodetectors  12  are formed on a substrate  16  made of a transparent or translucent dielectric, for example, glass or plastic. 
         [0049]    Each photodetector  12  comprises a stack comprising, in the following order from substrate  16 : 
         [0050]    a transparent electrode  18  made of a TCO material; 
         [0051]    an electron injection portion  20 , for example, made of heavily-doped transparent organic semiconductor polymer or of a transparent conductive metal oxide, for example, of ZnO type; 
         [0052]    a portion  22  made of a mixture of organic semiconductor polymers, for example poly(3-hexylthiophene) or poly(3-hexylthiophene-2,5-diyl) (P-type semiconductor), known as P3HT, mixed with [6,6]-phenyl-C 61 -butyric acid methyl ester (N-type semiconductor), known as PCBM; 
         [0053]    a portion  24  of heavily-doped organic semiconductor polymer (for example, a polymer known as PEDOT:PSS, which is a mixture of poly(3,4)-ethylenedioxythiophene and of sodium polystyrene sulfonate; 
         [0054]    a conductive layer  26 , for example, a conductive ink, particularly comprising metal particles embedded in a conductive polymer of silver ink type; 
         [0055]    an electrode  28 , for example, made of gold or silver. 
         [0056]    A protective coating  30  covers the upper surface of the array (on the side of electrode  28 ). 
         [0057]    Photoactive portions  22  of photodetectors  12  are here intended to be illuminated through substrate  16  and through electrodes  18  and portions  20 . The light radiation is schematically shown by arrows  32 . 
         [0058]    Photodetector array  12  may be a passive array or an active array. For a passive array, transparent electrodes  18  may correspond to parallel rectilinear strips, and each strip may be connected to all the photodetectors  12  of a same row. For an active array, transparent electrodes  18  may correspond to a continuous layer in contact with all the photodetectors  12  of the array. As a variation, transparent electrodes  18  may be isolated from one another, photodetectors  12  being in this case independent from one another. 
         [0059]    To provide a satisfactory conduction of transparent electrodes  18 , thickness e 1  of electrodes  18  of TCO material is greater than 50 nm. 
         [0060]    The TCO materials used to form transparent electrodes  18  are brittle materials. When they are submitted to excessive stress, such materials may lose their properties, particularly in terms of conduction. Indeed, beyond a given stress value, cracks appear in the TCO material, which cracks cause a decrease in the electric conductivity of electrodes  18 . There exist several techniques to mechanically characterize such materials, particularly the use of test bars for traction or compression tests, to determine characteristic physical values such as the Young&#39;s modulus, Poisson&#39;s ratio, or the elongation at break. For TCO materials, the elongation at break is generally small, for example, no more than 10%. 
         [0061]      FIGS. 2 and 3  schematically and partially show an embodiment of a user interface device  50  according to the invention.  FIG. 3  is a cross-section view along plane of  FIG. 2  and  FIG. 2  is a cross-section view along plane II-II of  FIG. 3 . 
         [0062]    User interface device  50  comprises the elements of user interface device  10 . However, unlike user interface device shown in  FIG. 1 , user interface device  50  comprises connection elements  52  interposed between transparent electrodes and substrate  16 . Electrodes  18  are thus not in direct contact with substrate  16  but are spaced apart from substrate  16  by connection elements  52 . The interval between substrate  16  and each electrode  18  is greater than or equal to 20 nm. The surface area of electrodes  18  opposite substrate  16  is designated with reference numeral  54 . Surface  54  is preferably planar. The contact surface between each connection element  52  and the associated electrode  18  is designated with reference numeral  56 . Contact surface area  56  of all connection elements is smaller than surface area  54  of electrodes  18  opposite substrate  16 . Advantageously, contact surface area  56  of all connection elements  52  is smaller than 50%, preferably than 70%, of surface area  54  of electrodes  18  opposite substrate  16 . Preferably, contact surface area  56  of all connection elements  52  is greater than 10% of surface area  54  of electrodes  18  opposite substrate  16 . Except for connection elements  52 , electrodes  18  are separated from substrate  16  by a gas or a gaseous mixture, for example, by a neutral gas, a mixture of neutral gases, or by air. Advantageously, contact surface area  56  is in the range from 10% to 50% of surface area  54  of electrodes  18  opposite substrate  16 . 
         [0063]    Connection elements  52  are made of a material more flexible than the conductive transparent material forming electrodes  18 . Flexible material means a material capable of resiliently deforming and, in particular, a material having an elongation at break greater than 10%, preferably greater than 50%, more preferably greater than 100%, particularly greater than 300%. 
         [0064]    The flexible material for example is a resist. It may be a “positive” resist. The resist portion exposed to a specific radiation then becomes soluble in a specific aqueous or organic solution, called developer solution, and the non-exposed resist portion remains non-soluble in the developer solution. It may be a “negative” resist. The resist portion exposed to the radiation becomes non-soluble in the developer solution and the non-exposed resist portion remains soluble in the developer solution. The flexible material may correspond to a mixture of a resist and of an elastomer. An elastomer is a polymer having a high elongation at break. 
         [0065]    Examples of resist comprise the following compounds: 
         [0066]    phenolformaldehyde, for example, a mixture of diazonaphtoquinone (or DNQ) and of a novolac resin (phenolformaldehyde resin); 
         [0067]    polyhydroxystyrene; 
         [0068]    poly(methyl methacrylate) or PMMA; 
         [0069]    poly(methyl glutarimide) or PMGI; and 
         [0070]    epoxy-based polymer (for example, the resist sold under trade name SU-8 by Micochem). 
         [0071]    In the present embodiment, electrodes  18  are rectilinear strips. The rectilinear strips are connected at one end to a processing circuit, not shown. A connection element  52  is associated with each electrode  18  and corresponds to a rectilinear strip extending between electrode  18  and substrate  16 . As a variation, a plurality of connection elements may be arranged between each electrode  18  and substrate  16 . 
         [0072]    Electrodes  18  are made of TCO material. Examples of transparent conductive oxides are: 
         [0073]    indium tin oxide or ITO; 
         [0074]    tin oxide; 
         [0075]    fluorine doped tin oxide or FTO; 
         [0076]    zinc oxide; 
         [0077]    aluminum doped zinc oxide or AZO; and 
         [0078]    indium-doped cadmium oxide. 
         [0079]    The dimensions of user interface device  50  are, as an example, the following: 
         [0080]    thickness e 2  of substrate  16 : from 20 μm to 125 μm; 
         [0081]    thickness e 1  of each electrode  18 : from 50 nm to 500 nm, preferably from 50 nm to 200 nm, more preferably in the order of 125 nm; 
         [0082]    thickness e 3  of photodetector element  12 , that is, thickness of the stack formed by layers  20 ,  22 ,  24 , and  26 : 500 nm; 
         [0083]    thickness e 4  of each electrode  28 : from 100 nm to 500 nm; and 
         [0084]    thickness e 5  of coating  30 : from 20 to 200 
         [0085]    Each connection element  52  has a thickness e 6 , measured along a direction perpendicular to the cross-section plane of  FIG. 3 , in the range from 1 to 100 and a thickness e 7 , measured along the stacking direction of photodetector  12 , in the range from 20 nm to 5 μm. 
         [0086]    When each electrode  18  corresponds to a rectilinear strip, length L 1  of each electrode  18  is for example in the range from 10 to 1 mm. 
         [0087]    According to an embodiment, device  50  is capable of detecting variations of the cast shadow of an actuating member  14  on sensor array  12 , when the actuating member is arranged between a light source and the array, and of deducing therefrom information representative of a variation of the position of the actuating member. Actuating member  14  may be the user&#39;s finger, hand, or any other object. The light source is preferably ambient light, for example, the sun or the interior electric lighting of a room in a building. 
         [0088]    When actuating member  14  is placed between the light source and the sensor array, the cast shadow of the actuating member on the sensor array causes a decrease in the light intensity received by some of sensors  12 . This enables device  50  to detect the presence of actuating member  14  close to the array. 
         [0089]    According to another embodiment, user interface device  50  is capable of using the image of actuating member  14 , seen by photon sensors  12 , to obtain information relative to the position of the actuating member. It should be noted that in practice, the cast shadow and the image of actuating member  14  do not coincide, except if the light source is placed exactly in the axis of projection of the actuating member on the sensor array. As a variation, user interface device  50  may detect both the cast shadow and the image of actuating member  14  to obtain a more accurate information relative to the position or to the position variations of the actuating member. 
         [0090]    It should be noted that “position of actuating member  14 ” here means a relative position relative to user interface device  50 . An embodiment where the user interface device  50  is displaced may be provided, actuating member  14  remaining fixed. 
         [0091]    Although this has not been shown in the drawings, device  50  may comprise means for processing the signals delivered by photodetectors  12  (for example, a microprocessor), and means of communication with a device or a system to be controlled (wire or wireless link). 
         [0092]    Further, and although this has not been shown, each photodetector  12  may comprise a focusing lens, for example, a Fresnel lens. A lens network also forms an interface between the photosensitive region of photodetector array  12  and substrate  16 , or is integrated to substrate  16 . The use of lenses enables to improve the lateral resolution of detection of the actuating member, particularly when it is remote from user interface device  50 . 
         [0093]    When a deformation is applied to user interface device  50 , substrate  16  deforms. Flexible connection elements  52  behave as dampers and decrease the transmission of deformations to transparent electrodes  18 . The appearing of stress in electrodes  28  is thus decreased. Connection elements  52  are flexible piles capable of moving to absorb the mechanical stress due to the flexion of deformable substrate  16 . Further, connection elements  52  enable to decrease the mechanical stress present in pixels  12  by decreasing the contact surface area between connection elements  52  and electrodes  18 . 
         [0094]    Photodetector array  12  may be an “active” array. Each photodetector  12  can then be individually selected. For this purpose, it may be provided to have, in the photodetector array, one or a plurality of access transistors associated with each photodetector. The transistors may also be formed from organic semiconductor materials in liquid or gel form, by printing techniques. The transistors may be provided on the side of coating  30 . Photodetector array  12  may be a “passive” array. Transparent electrodes  18  may then correspond to parallel rectilinear strips extending along the array rows and metal electrodes  28  may correspond to rectilinear strips extending along the array columns. 
         [0095]      FIGS. 4 to 7  are cross-section views illustrating several profiles for connection element  52 . In  FIG. 4 , connection element  52  has a rectangular profile. In  FIG. 5 , connection element  52  has a biconcave profile. In  FIG. 6 , connection element  52  has a trapezoidal profile having its smaller base attached to electrode  18  and having its larger base attached to substrate  16 . In  FIG. 7 , connection element  52  has a trapezoidal profile having its smaller base attached to substrate  16  and having its larger base attached to electrode  18 . Each profile may be advantageous according to the layers and manufacturing techniques used. The profile of  FIG. 4  is technologically easier to form and provides a good stress resistance. A main advantage of the profile of  FIG. 5  is to have a larger surface area of contact with substrate  16  and electrode  18  while keeping a small central section. This enables to both have a good bonding to substrate  16  and electrode  18  and to keep advantageous mechanical properties via the small central section.  FIGS. 6 and 7  also use this advantage by preferably promoting the bonding to substrate  16  ( FIG. 6 ) or to electrode  18  ( FIG. 7 ). 
         [0096]      FIG. 8  is a view similar to  FIG. 2  of another embodiment of user interface device  57 . In this embodiment, device  57  further comprises conductive elements  58  arranged on substrate  16 . Connection elements  52  connect conductive elements  58  to electrodes  18 . Conductive elements  58  may correspond to rectilinear strips. Conductive elements  58  may be metal elements, for example, made of silver. The thickness of conductive elements  58  is in the range from 10 nm to 500 nm. It is possible for conductive elements  58  not to be transparent. 
         [0097]    Connection elements  52  have the previously-described properties and are further conductive. They may be made of insulating resist with an added conductive elastomer (for example, a silicon elastomer filled with conductive particles). The proportion of conductive elastomer varies from 1% to 10% by mass with respect to the mass of connection element  52 . 
         [0098]    The elongation at break of the conductive elastomer is in the range from 100% to 300%. It may be silicone filled with conductive particles. Preferably, silicone is stable from −50° C. to +125° C. The metal particles may be particles of copper and silver, of pure silver, of nickel and graphite, of aluminum and silver, and/or of aluminum. The elastomer may comprise from 1% to 50% by mass of metal particles with respect to the elastomer mass. The metal particles for example have an average diameter which varies from a few nanometers to several micrometers. The electric resistivity of the elastomer is for example smaller than 0.007 Ω·cm. Such an elastomer may correspond to the elastomer sold by GETELEC under trade name GT 2000. 
         [0099]    Photodetectors  12  are thus continually electrically connected to conductive elements  58 , whatever the stress state of substrate  16 . 
         [0100]      FIG. 9  is a view similar to  FIG. 2  of another embodiment of user interface device  60 . In this embodiment, device further comprises conductive elements  62  arranged on substrate  16 , on the side of connection elements  52  and partly extending under transparent electrodes  18 . Conductive elements  62  define openings  64  to allow the passage of light radiation towards sensors  12 . Conductive elements  62  may be metal elements, for example, made of silver. Thickness e 8  of conductive elements  62  is smaller than thickness e 7  of connection elements  52 . Thickness e 8  of conductive elements  62  is in the range from 10 nm to 500 nm. It is possible for conductive elements  62  not to be transparent. 
         [0101]    Conductive elements  62  may correspond to rectilinear strips. As an example, when transparent electrodes  18  correspond to parallel rectilinear strips, conductive elements  62  may correspond to rectilinear strips parallel to electrodes  18 . 
         [0102]      FIG. 10  shows a cross-section view of  FIG. 9  along line X-X and shows an embodiment of conductive elements  62  and of connection elements  52 . In this embodiment, connection elements  52  have the shape of pads, for example, having a square or rectangular cross-section, and conductive elements  62  are connected to one another and define openings  64  around each connection element  52 . Openings  64  may have a square, rectangular, circular, elliptic, etc. cross-section. Each opening  64  is substantially in line with a photodetector stack  12  to allow the passage of light rays. 
         [0103]      FIG. 11  shows device  60  when a pressure is exerted on coating  30 , for example, by actuating member  14 . In the present embodiment, conductive elements  62  are connected to a processing circuit, not shown. When user interface device  60  is not deformed, transparent electrodes  60  are not in contact with conductive elements  62 . User interface device  60  does not operate. When a pressure is exerted on device  60 , an area  65  of deformation of coating  30  appears under the action of actuating member  14 . This causes a deformation of connection elements  52  connected to photodetectors  12  in deformation area  65 . Photodetectors  12  displace all the way to come into contact with the adjacent conductive elements  62 . Only the signals stored in photodetectors  12  thus connected to conductive elements  62  may be measured by the processing circuit. Device  60  may be used simultaneously as a contactless detection display and as a touch-sensitive display. As a variation, the deformation may be applied on the side of substrate  16 . In  FIG. 11 , a photodetector  12  has been shown in deformation area  65  in contact with the two adjacent conductive elements  62  interposed between electrode  18  and substrate  16 . As a variation, according to the location of deformation area  65 , the deformation of connection elements  52  may result in an inclination of photodetectors  12  until they come into contact with a single one of conductive elements  62  of the pair of conductive elements  62  interposed between electrode  18  and substrate  16 . 
         [0104]    An example of application for example is to ascertain that contactless user interface device  60  only operates when it is properly deformed. As an example, user interface device  60  is initially in a planar configuration where photodetectors  12  are not connected to conductive elements  62 . Contactless user interface device  60  then does not operate. According to the targeted application, the user interface device is applied to the surface of a support which is not planar. This results in a deformation of user interface device  60  and in putting into contact transparent electrodes  18  with conductive elements  62 . User interface device  60  can then be used as a contactless display. The user interface device is then idle when the substrate is not submitted to a mechanical deformation and is functional when the substrate is submitted to a mechanical deformation. 
         [0105]      FIGS. 12A to 12G  illustrate the structures obtained at successive steps of an embodiment of a method of manufacturing user interface device  60  shown in  FIG. 9 . 
         [0106]      FIG. 12A  shows the structure obtained after a step of forming conductive elements  62  on substrate  16 . As an example, conductive elements  62  are formed on substrate  16  by a vapor deposition method. 
         [0107]      FIG. 12B  shows the structure obtained after having covered the structure of  FIG. 12A  with a resist layer  64 , to totally cover conductive elements  62 , and then after having deposited, on resist layer  64 , a layer  66  of TCO material, for example, ITO. In the present embodiment, the resist is a negative resist. Resist layer  64  may be deposited by a spin coating method. TCO material layer  66  may be deposited by cathode sputtering. 
         [0108]      FIG. 12C  shows the structure obtained after a step of exposing resin layer  64  to a radiation through a mask  68 , or illumination step, to form patterns  70  in resin layer  64 . Patterns  70  are shown by dotted lines in the different drawings. Mask  68  comprises openings  74  reproducing a pattern to be transferred to resin layer  64 . The radiation used to expose resist layer  64  is shown by arrows  76 . 
         [0109]    As a variation, the step of depositing TCO material layer  66  may be carried out after the step of exposing resin layer  64 . 
         [0110]      FIG. 12D  shows the structure obtained after a step of etching ITO layer  66  to define transparent electrodes  18 . The etching of ITO layer  66  may be a laser etching. 
         [0111]      FIG. 12E  shows the structure obtained after the partial removal of resin layer  64  to define connection elements  52 . The removal of resin layer  64  may be performed by dissolving the non-illuminated resist portions in an adapted aqueous or organic solution. 
         [0112]      FIG. 12F  shows the structure obtained after the forming of photodetectors  12 . The stacks forming photodetectors  12  may be formed by printing methods. The materials of abovementioned portions  20  to  26  are deposited in liquid form, for example, in the form of conductive and semiconductor inks by means of inkjet printers. It should here be noted that materials in liquid form here also include gel materials capable of being deposited by printing techniques. Anneal steps may be provided between the depositions of the different layers, but the anneal temperatures cannot exceed 150° C., and the deposition and the possible anneals may be performed at the atmospheric pressure. The forming of organic semiconductor components by printing techniques is for example described in article “CEA-LITEN S2S Printing Platform for Organic CMOS and Sensors Devices” by Jean-Yves Laurent et al, LOPE-C Conference, June 2011, Frankfurt. 
         [0113]      FIG. 12G  shows the structure obtained after covering the structure shown in  FIG. 12F  with coating  30  provided with metal electrodes  28 . The fastening of metal electrodes  28  to portions  26  of photodetectors  12  may be performed by lamination with, for example, the use of conductive glues. 
         [0114]      FIGS. 13A to 13G  show the structures obtained at successive steps of another embodiment of a method of manufacturing user interface device  60  shown in  FIG. 9 . 
         [0115]      FIGS. 13A to 13C  are identical respectively to  FIGS. 12A to 12C  described hereabove. 
         [0116]      FIG. 13D  shows the structure obtained after having deposited on layer  66 , successively, layers  80 ,  82 ,  84 , and  86 . Layer  80  for example is a zinc oxide layer (electron donor layer). Layer  82  is an organic semiconductor polymer. Layer  84  is made of a heavily-doped organic semiconductor polymer (hole donor layer). Layer  86  is made of a conductive material, for example, carbon. Layers  80 ,  82 ,  84 , and  86  may be deposited by silk screening, inkjet printing, or spin coating. 
         [0117]      FIG. 13E  shows the structure obtained after etching layers  86 ,  84 ,  82 ,  80 , and  66  to successively define portions  26 ,  24 ,  22 , and  20  of each photodetector  12  and to define transparent electrodes  18 . It may be a laser etching. Preferably, each layer  86 ,  84 ,  82 ,  80 , and  66  is successively etched. Indeed, the laser etching conditions may be specific for each layer  86 ,  84 ,  82 ,  80 , and  66 . 
         [0118]      FIG. 13F  shows the structure obtained after the partial removal of resin layer  64  to define connection elements  52 . The removal of the resin layer may be performed by dissolving the non-illuminated resist portions in an adapted aqueous or organic solution. 
         [0119]      FIG. 13G  is identical to previously-described  FIG. 12G . 
         [0120]    Specific embodiments of the present invention have been described. Various alterations and modifications will occur to those skilled in the art. In particular, although the present invention has been described for a user interface device having connection elements  52  located between electrodes  18  and substrate  16  or between electrodes  18  and conductive elements  58 , connection elements  52  may be arranged between electrodes  28  and coating  30 . Further, connection elements  52  may be provided both between electrodes  18  and substrate  16  (or conductive elements  58 ) and between electrodes  28  and coating  30 . This last case advantageously enables to distribute the stress both on the top and on the bottom of each photodetector  12  and thus to further avoid the occurrence of excessive stress. 
         [0121]    Further, although the present invention has been described for a user interface device comprising a photodetector array, the present invention may apply to a display screen comprising an array of photon emitter elements or of elements modifying the passing of photons, connected to transparent TCO electrodes covered with a transparent substrate. 
         [0122]    Various embodiments with different variations have been described hereabove. It should be noted that those skilled in the art may combine various elements of these various embodiments and variations without showing any inventive step. As an example, the profiles of connection elements  52  shown in  FIGS. 5 to 7  may be implemented with the embodiments of the user interface device shown in  FIGS. 8 and 9 .