Opto-capacitive sensor

Abstract

An optoelectronic capacitive sensor (29) comprises an input surface (30) and one or more light sources (31) arranged to illuminate a portion (35) of the input surface (30). The optoelectronic capacitive sensor (29) further comprises an array (36) of optoelectronic capacitors arranged (32) to receive light (38) from the one or more light sources (31) reflected from an object (39) in contact with or in proximity to the illuminated portion (35) of the input surface (30). The array (36) of optoelectronic capacitors (32) is configured to detect a reflection pattern of the object (39).

Description

TECHNICAL FIELD

[0001] The present invention relates to photo-capacitance sensors, in particular photo-capacitance sensors for detecting a pattern in reflected light. Photo-capacitance sensors can be used for biometric authentication, for example sensing a fingerprint or other unique pattern. Photo-capacitance sensors can be incorporated into touch screen display panels. BACKGROUND

[0002] Photo-capacitance effects involve a change in the space charge distribution of a material in response to illumination with light in a range of wavelengths. If the material is incorporated between electrodes of a capacitor, the presence and / or intensity of the illumination can be determined based on measuring the change in capacitance of the capacitor.

[0003] J.C. Anderson (1982) “Theory of photo-capacitance in amorphous silicon MIS structures” (Journal of Physics B, 46:2, 151-161, 1982, DOI: 10.1080 / 13642818208246431) describes a theoretical treatment of photo-capacitance effects in silicon metal-insulator-semiconductor (MIS) structures.

[0004] D. Caputo, G. de Cesare, A. Nascetti, F. Palma and M. Petri “Infrared photodetection at room temperature using photocapacitance in amorphous silicon structures” (Applied Physics Letters, 72, 1229 (1998); https: / / doi.org / 10.1063 / 1.121022) describe a device based on amorphous silicon material that is able to detect infrared light by capacitance measurement at room temperature.

[0005] M. Tucci, D. Caputo, Study of capacitance in hydrogenated amorphous silicon phototransistors for imaging arrays, Journal of Non-Crystalline Solids, 338-340 (2004) 780-783, https: / / doi.org / 10.1016 / j.jnoncrysol.2004.03.090, describes a study of the capacitance of hydrogenated amorphous silicon phototransistors to determine their suitability for use in large area imaging systems. SUMMARY

[0006] According to a first aspect of the application, there is provided a photo-capacitive sensor comprising an input surface and one or more light sources arranged to illuminate a portion of the input surface. The photo-capacitive sensor further comprises an array of photo-capacitors arranged to receive light from the one or more light sources, the light being reflected from an object in contact with or in proximity to the illuminated portion of the input surface. The array of photo-capacitors is configured to detect a reflection pattern of the object.

[0007] The reflection pattern can correspond to an albedo pattern, a colour pattern and / or a relief pattern. The reflection pattern can correspond to a fingerprint and / or another pattern of skin ridges.

[0008] The array of photo-capacitors can be configured to detect a fingerprint.

[0009] The spacing between the photo-capacitors within the array can be less than 1 mm. The spacing between the photo-capacitors within the array can be less than 0.5 mm. The spacing between the photo-capacitors within the array can be small enough to resolve fingerprint ridges. The array of photo-capacitors can be configured to detect a pattern of human skin ridges.

[0010] Each photo-capacitor can comprise or be formed from a disordered, crystalline or polycrystalline material. Each photo-capacitor can comprise or be formed from a material that includes a trapped state in the material bandgap that is capable of absorbing sub-bandgap photon energies. Each photo-capacitor can comprise or be formed from one or more of amorphous silicon, amorphous semiconductor oxide, organic material, etc.

[0011] The term“proximity” can refer to an object being sufficiently close to the input surface such that the reflected pattern is resolvable given the pitch / spacing of the photocapacitors within the array. The maximum distance can depend on the dispersion of the light provided by the light source and the spatial frequency of the reflected pattern, among other factors. For example, for reading fingerprints, photographs, documents, etc., proximity can refer to less than or equal to 1 mm for collimated or laser light sources, and less than or equal to 0.1 mm for non-collimated light sources. For detecting the shape of a fingertip or hand, the distance can be greater, e.g., less than or equal to 100 mm for collimated or laser light sources, or less than or equal to 10 mm for non-collimated light sources. In challenging applications such as resolving subcutaneous tissue (e.g., veins), proximity can refer to less than or equal to 0.5 mm for collimated or laser light sources.

[0012] The photocapacitive sensor can be implemented as part of a passive sensor and / or a passive sensing layer. The photocapacitive sensor can be implemented as part of an active sensor and / or an active sensing layer. The photocapacitive sensor can be implemented as part of a button, touchpad, touch panel, touchscreen display, etc.

[0013] The photocapacitive sensor can be operable when the input surface is wetted and / or submerged by water or any other fluid that is transparent at the wavelengths emitted by the light source and to which the photocapacitors are sensitive.

[0014] The one or more light sources can be directional and can emit light toward the input surface. The one or more light sources can be disposed between the photocapacitor array and the input surface.

[0015] The photocapacitor array can be disposed between the one or more light sources and the input surface. The photocapacitive sensor can further include a light-attenuating layer disposed between the one or more light sources and the photocapacitor array. The light-attenuating layer can be configured to shield the photocapacitors from direct illumination by the one or more light sources in a wavelength range to which the photocapacitors are sensitive.

[0016] The light-attenuating layer can be patterned. The light-attenuating layer can be opaque and can substantially or completely block light. The light-attenuating layer can selectively block light and can take the form of a light filter configured to block light in a wavelength range. The light-attenuating layer can take the form of a polarizer.

[0017] The one or more light sources can include one or more infrared emitters. The infrared emitters can include or take the form of light-emitting diodes. The infrared emitters can correspond to a peak emission in a range between 800 nm and 2,500 nm, inclusive.

[0018] The one or more light sources can comprise one or more emitters selected from red, green, and blue emitters. The red emitters can comprise or take the form of light emitting diodes. The red emitters can correspond to a peak emission in a range between 700 nm and 635 nm, inclusive.

[0019] The optoelectronic capacitor array can comprise a plurality of first electrodes extending in a first direction and spaced apart in a second, different direction. The optoelectronic capacitor array can comprise a plurality of second electrodes extending in the second direction and spaced apart in the first direction. The optoelectronic capacitor array can comprise a layer of optoelectronic capacitor material disposed between the first electrodes and the second electrodes such that each intersection of a first electrode and a second electrode provides an optoelectronic capacitor of the array.

[0020] The optoelectronic capacitor array can comprise a plurality of first electrodes extending in a first direction and spaced apart in a second, different direction. The optoelectronic capacitor array can comprise a plurality of second electrodes extending in the second direction and spaced apart in the first direction. The plurality of first electrodes and the plurality of second electrodes can be substantially coplanar, and can be disposed on or above a layer of optoelectronic capacitor material such that each intersection of a first electrode and a second electrode provides an optoelectronic capacitor of the array.

[0021] The optoelectronic capacitor array can comprise, in order, a plurality of first electrodes extending in a first direction and spaced apart in a second, different direction, a layer of dielectric, a plurality of second electrodes extending in the second direction and spaced apart in the first direction, and a layer of optoelectronic capacitor material. The optoelectronic capacitor array can comprise, in order, a layer of optoelectronic capacitor material, a plurality of first electrodes extending in a first direction and spaced apart in a second, different direction, a layer of dielectric, and a plurality of second electrodes extending in the second direction and spaced apart in the first direction.

[0022] The optoelectronic capacitor array can comprise a plurality of first electrodes extending in a first direction and spaced apart in a second, different direction. The optoelectronic capacitor array can comprise a plurality of second electrodes extending in the second direction and spaced apart in the first direction. The plurality of first electrodes and the plurality of second electrodes can be substantially coplanar, and a layer of optoelectronic capacitor material can be substantially coplanar with the first electrodes and the second electrodes and disposed in gaps separating the first electrodes and the second electrodes.

[0023] The optoelectronic capacitor sensor can further comprise one or more conductive traces for projecting the capacitive measurement.

[0024] The display screen can comprise a cover plate and a display stack. The display stack can comprise the optoelectronic capacitor sensor according to the first aspect. The cover plate can provide an input surface.

[0025] The display stack can comprise a backlight layer. The backlight layer can provide the one or more light sources, or the backlight layer can comprise the one or more light sources. The backlight layer can comprise the one or more light sources and one or more additional light emitters. The backlight layer can consist of the one or more light sources.

[0026] The display stack can comprise a pixel layer in the form of an array of light emitting diodes. The array of light emitting diodes can provide the one or more light sources, or the array of light emitting diodes can comprise the one or more light sources. The pixel layer can comprise the one or more light sources and one or more additional light emitters. The pixel layer can consist of the one or more light sources.

[0027] The display stack can comprise a thin-film transistor layer. The thin-film transistor layer can provide the array of opto-capacitors, or the thin-film transistor layer comprises the array of opto-capacitors. The opto-capacitor sensor can be implemented as part of the thin-film transistor layer. The opto-capacitor sensor can be in the form of a thin-film transistor with a shorted source and drain to form a capacitor between the gate and the connected source and drain.

[0028] The display stack can comprise a thin-film transistor layer and a separate opto-capacitor layer. The separate opto-capacitor layer can provide and / or define the array of opto-capacitors.

[0029] The display stack can have a display area. The (illuminated) part of the input surface can correspond to a first region of the display area.

[0030] The display screen can further comprise a second opto-capacitor sensor according to the first aspect. The second opto-capacitor sensor can be associated with a part of the input surface corresponding to a second region of the display area different from the first region.

[0031] The display stack has a display area, and the (illuminated) part of the input surface can substantially correspond to the display area. It can substantially correspond to the display area if the (illuminated) part of the input surface corresponds to 90% or more of the display area.

[0032] The display stack can comprise conductive traces for projected capacitive touch sensing.

[0033] The access control device can comprise an opto-capacitor sensor or a corresponding display screen.

[0034] The access control device can be used to activate equipment, such as a printer, a medical device, a door, an elevator (lift) control panel, a motor vehicle, a motorcycle, a bicycle, construction equipment such as a bulldozer, a trencher, an excavator, and an airplane, military equipment. The access control device can be used to activate equipment, such as a medicine cabinet, a hospital room (such as a maternity ward and a maternity ward), a hotel room door, a hotel back office door, or any other room or space for which access is desired to be controlled.

[0035] The device can include a photo-capacitance sensor, a display screen, and / or the access control apparatus described above. The device can further include a controller connected to the photo-capacitance sensor and configured to measure a capacitance of the photo-capacitor array.

[0036] The controller can be further configured to measure a photo-capacitance component of the capacitance of the photo-capacitor array.

[0037] The controller can be configured such that measuring the photo-capacitance component includes measuring a capacitance of at least a subset of the photo-capacitor array. Measuring the photo-capacitance component can further include determining an interaction zone based on the capacitance of the subset of the photo-capacitor array. Measuring the photo-capacitance component can further include deactivating each light source corresponding to the interaction zone, measuring a projected capacitance component of each photo-capacitor corresponding to the interaction zone. Measuring the photo-capacitance component can further include activating at least a subset of light sources corresponding to the interaction zone. Measuring the photo-capacitance component can further include measuring a total capacitance of each photo-capacitor corresponding to the interaction zone. Measuring the photo-capacitance component can further include determining the photo-capacitance component corresponding to the interaction zone based on a difference between the total capacitance and the respective projected capacitance component.

[0038] The subset of the photo-capacitor array can include all photo-capacitors. The subset of light sources can include all light sources. The subset of light sources can include all light sources of a particular color. For example, a display can include red (R), green (G), and blue (B) pixels, and all pixels can be deactivated to measure a projected capacitance component, and then only the red (R) light sources can be activated to measure a total capacitance. In other examples, the display can further include IR light sources over at least a portion of the display surface, and for the purpose of determining the photo-capacitance component, only the IR light sources can be reactivated.

[0039] The process of deactivating and activating light sources can be repeated any number of times in order to refine the photo-capacitance component, for example, by averaging. When the light sources include two or more colors, the process of deactivating and activating light sources can be repeated one or more times, activating only light sources of a single color for each measurement of total capacitance. In this way, a photo-capacitance component can be obtained independently for each different color of light source available.

[0040] As described above, the photo-capacitor array can take the form of intersections between a plurality of first electrodes and a plurality of second electrodes. In this case, the controller can use the transmitter outputs to drive the first electrodes and the receiver inputs to monitor the second electrodes. Each transmitter output can provide a drive signal having a different frequency.

[0041] The controller can have a number of transmitter outputs less than the number of first electrodes, and each transmitter output can be connected to two or more first electrodes via a respective multiplexer. The output from the multiplexer can be connected to a subset of the spatially grouped first electrodes in the photo-capacitance sensor. In other words, each transmitter output can be multiplexed to first electrodes corresponding to a particular stripe or strip of the photo-capacitance sensor, the particular stripe or strip corresponding to a subset of the first electrodes. Alternatively, the output from two or more multiplexers can be interleaved such that in one or more spatially grouped subsets of first electrodes, each first electrode is connectable to a different transmitter output via a respective multiplexer. The latter option can allow all of the first electrodes within a particular stripe or strip of the photo-capacitance sensor corresponding to a subset of the first electrodes to be driven simultaneously for measurement.

[0042] The controller can have a number of receiver inputs less than the number of second electrodes, and the receiver inputs can be multiplexed to the second electrodes in any of the ways described with respect to the transmitter outputs and the first electrodes.

[0043] The device can include a display screen, where the display stack includes conductive traces for projected capacitance touch sensing, and a controller connected to the conductive traces for projected capacitance touch sensing and the photo-capacitance sensor via a switching network. The controller can be configured to time-division multiplex measurements of projected capacitance from the conductive traces and measurements of photo-capacitance from the photo-capacitance sensor using the switching network.

[0044] The device can include a display screen, where the display stack includes conductive traces for projected capacitance touch sensing, a controller connected to the photo-capacitance sensor and configured to measure photo-capacitance of the photo-capacitance array, and a dedicated touch controller connected to the conductive traces and configured to use the conductive traces for projected capacitance touch sensing.

[0045] The device can be configured to determine whether a user interaction corresponds to all or part of a user hand in contact with the input surface in response to detecting the user interaction using projected capacitance measurements. The device can be configured to determine one or more fingerprint regions in response to determining that the user interaction corresponds to all or part of a user hand. The device can be configured to measure photo-capacitance corresponding to each fingerprint region in response to determining one or more fingerprint regions.

[0046] The controller can store a reference frame corresponding to measured capacitance of the photo-capacitance array when the one or more light sources are illuminated without an object over or in contact with the input surface. The controller can be further configured to subtract the reference frame from the capacitance measured from the photo-capacitance array.

[0047] The controller can be further configured to control light emission from the one or more light sources. Alternatively, a second controller can be configured to control light emission from the one or more light sources.

[0048] The device can be further configured to cause, in response to detecting a touch using projected capacitance, the controller to measure capacitance of the array of photogalvanic capacitors.

[0049] The device can be further configured to cause, in response to detecting a touch using projected capacitance, the controller or a second controller to illuminate the one or more light sources, and the controller to measure capacitance of the array of photogalvanic capacitors.

[0050] The one or more light sources can include one or more infrared light sources and one or more red light sources. The controller or a second controller can be configured to illuminate the infrared light sources and measure a first set of capacitances from the array of photogalvanic capacitors. The controller or a second controller can be further configured to illuminate the red light sources and measure a second set of capacitances from the array of photogalvanic capacitors. The controller can be configured to compare the first set of capacitances and the second set of capacitances to determine whether an object above or in contact with the input surface corresponds to human skin.

[0051] The controller can be configured to determine whether an object above or in contact with the input surface corresponds to human skin by detecting whether a difference between reflections of infrared light and red light is consistent with oxygenated human tissue. In this way, spoofing of the sensor using a fingerprint facsimile can be detected and prevented.

[0052] The controller can be further configured to control the one or more infrared light sources and the array of photogalvanic capacitive sensors to detect and / or image one or more veins contained in the object.

[0053] The device can be configured to compare the measured capacitance pattern using the array to a set of one or more authorized patterns. The device can be further configured to output a signal in response to the measured capacitance pattern using the array matching an authorized pattern of the one or more authorized patterns.

[0054] The comparison of the capacitance pattern to the set of one or more authorized patterns can be conditioned on the measured capacitance pattern corresponding to an interaction area exceeding a minimum area. The size of the interaction area can be determined based on photogalvanic capacitance measurements obtained from the array of photogalvanic capacitive sensors and / or projected capacitance measurements obtained from the array of photogalvanic capacitive sensors and / or the conductive traces.

[0055] This condition can ensure that the comparison is based on a minimum area, which can help to reduce false matches and improve security. When the device includes a display and the interaction area is not sufficient for the comparison, the display can be controlled to display a message informing the user to reposition their finger (or palm, etc.) to allow for a more complete measurement.

[0056] The signal can activate a device, such as a printer, a medical device, a door, an elevator control panel, a motor vehicle, a motorcycle, a bicycle, a construction device such as a bulldozer, a trencher, an excavator, and an aircraft, a military device. The signal can activate a device, such as a medicine cabinet, a hospital room such as a maternity ward and a delivery room, a hotel room door, a hotel back-of-house door, or any other room or space for which access is desired to be controlled.

[0057] According to a second aspect of the application, there is provided a method of using a photoelectric capacitive sensor, a display screen, an access control device and / or a device, the method comprising measuring a capacitance of an array of photoelectric capacitors.

[0058] The method can comprise a feature corresponding to any feature of the photoelectric capacitive sensor, the display screen, the access control device and / or the device.

[0059] The method can further comprise retrieving or obtaining a reference frame corresponding to the measured capacitance of the array of photoelectric capacitors when the one or more light sources are illuminated in the absence of an object above or in contact with the input surface. The method can further comprise subtracting the reference frame from the capacitance measured using the array of photoelectric capacitors.

[0060] The method can further comprise comparing the pattern of capacitance measured using the array to a set of one or more authorised patterns. The method can further comprise outputting a signal in response to the pattern of capacitance measured using the array matching an authorised pattern of the one or more authorised patterns.

[0061] According to a third aspect of the application, there is provided a photoelectric capacitive sensor, the photoelectric capacitive sensor comprising an input surface and an array of photoelectric capacitors arranged to receive light from a light source transmitted through the input surface. The array of photoelectric capacitors is configured for detecting a laser point spot.

[0062] The configuration of the array of photoelectric capacitors is configured for detecting a laser point spot, which can correspond to a pitch of the array of between 1 mm and 5 mm, inclusive.

[0063] The photoelectric capacitive sensor of the third aspect can comprise a feature corresponding to any feature of the photoelectric capacitive sensor, the display screen and / or the device according to the first aspect and / or the method according to the second aspect.

[0064] According to a fourth aspect of the application, there is provided a system comprising an input surface. The system further comprises one or more light sources arranged to illuminate a portion of the input surface. The system further comprises a photocapacitor array arranged to receive light from the one or more light sources reflected from an object in contact with or in proximity to the illuminated portion of the input surface. The system further comprises a controller configured to detect one or more touches using the photocapacitor array based on a projected capacitance scan. The controller is further configured to obtain a fingerprint pattern corresponding to at least one of the one or more touches based on photocapacitance measurements obtained using the photocapacitor array.

[0065] The system of the fourth aspect can comprise features corresponding to any of the features of the photocapacitive sensor, display screen and / or device according to the first aspect and / or the method according to the second aspect.

[0066] The system can further comprise a display, and the system can be a touch screen system.

[0067] The one or more light sources can comprise, or take the form of, one or more infrared light sources. The controller can be configured to pulse at least one of the infrared light sources during measurement of the corresponding photocapacitance. The infrared light source can be a near-infrared light source. The term "gated" can be used as an alternative to the term "pulsed". BRIEF DESCRIPTION OF DRAWINGS

[0068] Certain embodiments of the application will now be described, by way of example only, with reference to the accompanying drawings in which:

[0069] Figure 1 A plan view of a mesh electrode is schematically illustrated;

[0070] Figure 2A A plan view of a frame electrode is schematically illustrated;

[0071] Figure 2B A plan view of an interdigitated electrode is schematically illustrated;

[0072] Figure 2C A plan view of a serpentine electrode is schematically illustrated;

[0073] Figure 2D A plan view of a nanowire mat electrode is schematically illustrated;

[0074] Figure 2E A plan view of a pillar structure electrode is schematically illustrated;

[0075] Figure 2F A plan view of a transparent electrode is schematically illustrated;

[0076] Figure 2G A plan view of a transparent electrode is schematically illustrated;

[0077] Figure 2H is a plan view of the opaque electrode;

[0078] Figure 2I is a plan view of the porous electrode;

[0079] Figure 3 schematically illustrates a first photoelectric capacitive sensor;

[0080] Figure 4 schematically illustrates an active sensing layer associated with the first photoelectric capacitive sensor;

[0081] Figure 5 schematically illustrates a second photoelectric capacitive sensor;

[0082] Figure 6 is a cross-sectional schematic view of a first display underlayment;

[0083] Figure 7 is a cross-sectional schematic view of a second display underlayment;

[0084] Figure 8 is a cross-sectional schematic view of a first battery overlayment;

[0085] Figure 9 is a cross-sectional schematic view of a second battery overlayment;

[0086] Figure 10 is a cross-sectional schematic view of a first battery inlayment;

[0087] Figure 11 is a cross-sectional schematic view of a second battery inlayment;

[0088] Figure 12 is a cross-sectional schematic view of a third battery overlayment;

[0089] Figure 13 is a cross-sectional schematic view of a fourth battery overlayment;

[0090] Figure 14 is a plan schematic view of a first display layout;

[0091] Figure 15 is a plan schematic view of a second display layout;

[0092] Figure 16 is a plan schematic view of a third display layout;

[0093] Figure 17 is a plan schematic view of a fourth display layout;

[0094] Figure 18 is a cross-sectional schematic view of a specific example of the second battery inlayment of Figure 11 ; and

[0095] Figure 19 is Figure 18 a cross-sectional schematic of a thin-film transistor (TFT) integrated opto-capacitor;

[0096] Figure 20 a system for opto-capacitive sensing is schematically illustrated;

[0097] Figure 21 a separate readout configuration for projected and opto-capacitance is schematically illustrated;

[0098] Figure 22A a time-division multiplexed readout configuration for projected and opto-capacitance is schematically illustrated;

[0099] Figure 22B a time-division multiplexed readout configuration for projected and opto-capacitance is schematically illustrated; Figure 22A a timing of the time-division multiplexed readout configuration illustrated in

[0100] Figure 23 a combined readout configuration for projected and opto-capacitance is schematically illustrated;

[0101] Figure 24 is a cross-sectional schematic of a third opto-capacitive sensor;

[0102] Figure 25 is a planar schematic of electrodes of the third opto-capacitive sensor;

[0103] Figure 26 electric field lines between electrodes of the third opto-capacitive sensor are schematically illustrated;

[0104] Figure 27 electric field lines between modified electrodes of the third opto-capacitive sensor are schematically illustrated;

[0105] Figure 28 a combined readout configuration illustrated in Figure 23 the interaction, dark, and measurement zones of the combined readout configuration illustrated in

[0106] Figure 29 a timing of the combined readout configuration illustrated in Figure 23

[0107] Figure 30A and Figure 30B measurements obtained during different time periods illustrated in Figure 29

[0108] a first addressing scheme for implementing the combined readout configuration illustrated in Figure 31 Figure 23

[0109] Figure 32 a second addressing scheme for implementing the combined readout configuration illustrated in​​​Figure 23 second addressing scheme for the illustrated combined readout configuration;

[0110] Figures 33A to 33D entire hand / palm projected capacitive sensing, and corresponding measurement areas for optoelectronic capacitive sensing are schematically illustrated;

[0111] Figures 34A to 36B relative areas corresponding to user touches with different applied forces are schematically illustrated; and

[0112] Figure 37 a presentation system including a fourth optoelectronic capacitive sensor is schematically illustrated. DETAILED DESCRIPTION

[0113] Hereinafter, like parts are denoted by like reference numbers.

[0114] The use of biometric authorization is increasing for various purposes, such as providing fast access to smartphones, tablets, and other devices. Biometric authorization can also be used in software applications, for example, to authorize financial transactions. Other applications of biometric authorization are described below.

[0115] One prior art is based on visible light reflection from, for example, a user's finger, and subsequent detection of the fingerprint using an array of photodetectors. The fingerprint sensor is typically provided in or under a button separate from the display. It is desirable to position the fingerprint sensor within the same area as the display, for example, to allow the use of a fingerprint biometric without sacrificing display area.

[0116] This specification relates to optoelectronic capacitive sensors, which can be used to provide integrated in-display fingerprint readers for user / application authorization, among other applications described below. In contrast to prior art methods based on photodetectors (e.g., photodiodes), this specification proposes the use of an array of optoelectronic capacitors, which can detect light reflected from a pattern (e.g., a fingerprint) placed close to or in contact with an input surface (e.g., a phone screen). The use of optoelectronic capacitors can allow greater flexibility in the placement of the pattern sensor within the display. For example, some examples can use infrared (IR) reflections from a finger, which are then detected by an array of optoelectronic capacitors. This can be advantageous in view of the limited or reduced IR absorption of most materials used in display modules, thereby enabling the placement of the array of optoelectronic capacitors at various heights within the display stack.

[0117] The spatial resolution of the opto-capacitive sensor according to the present description can be adjusted according to the type of reflection pattern intended to be read. For example, to detect fingerprints using an integrated display array, the opto-capacitors can be located at each (R-G-B) pixel or at each R, G, B sub-pixel. For high resolution displays, every nth pixel (where n is a positive integer) can be sufficient, as the spatial scale of the pattern intended to be read determines the resolution required.

[0118] The opto-capacitive sensor according to the present description can be used in conjunction with (or even integrated with) capacitive touch sensing. One factor that can increase the flexibility of the opto-capacitor location is the non-simultaneous readout of the capacitive touch and the opto-capacitance, as they are two different interaction modes.

[0119] In other devices, the opto-capacitive sensor according to the present description can be embedded in current display architectures, such as the so-called "in-cell", "on-cell", "in-cell hybrid" solutions, and / or future variants thereof using embedded touch solutions.

[0120] Opto-capacitance

[0121] Reference is made to Figure 1 , which shows an opto-capacitor 1.

[0122] The opto-capacitor 1 comprises a layer of opto-capacitive material 2 located between a first electrode 3 and a second electrode 4. The opto-capacitive material 2 is a material that exhibits an opto-capacitive effect. Without wishing to be bound by theory, a short explanation of the opto-capacitive effect can be helpful to understand the present description.

[0123] The opto-capacitance represents a change in the charge state of the material 2 when exposed to light. This change in charge state is different from the so-called geometric capacitance, which is inherent to the material and can be considered as a dark capacitance.

[0124] The opto-capacitance can be observed in disordered materials where carrier trapping is dominant. Unlike in crystals (or ordered materials) where, in the presence of illumination, electrons transition from the valence band to the conduction band (thus generating a photo-current that can be exploited), in disordered materials, illumination (depending on the wavelength / energy) can cause electrons to transition from the valence band states to localized trapping states. These electrons remain trapped and return to the valence band at some point in time. During this period, there is no photo-current as the carriers in the trapping states are immobile, but the capacitance changes, which can be used as a means of detecting illumination.

[0125] The wavelength or energy of the incident radiation plays an important role in the dynamics of the electronic transitions that generate the photo-capacitance. Disordered materials can have localized and deep defect states distributed within their bandgap energy. For example, a-Si:H has a bandgap of 1.7 eV, while amorphous oxide semiconductors (AOS) can have a bandgap exceeding 3 eV. When a photon with energy less than the bandgap energy is incident on a disordered semiconductor, an electron or hole from an extended (valence or conduction) state can be excited to fill a deep defect or tail state - this defines the process of charge trapping that changes the charge state of the material and its internal electric field distribution. As noted above, these trapped charges do not generate a photocurrent because they are fixed, but they do generate a photo-capacitance, which can be expressed as:

[0126]

[0127] where V is the electric potential applied between the electrodes of the photo-capacitor (e.g., photo-capacitor 1), Q 总计 is the total charge, Q 俘获 is the charge associated with the trapped states, and Q 导电 is the charge on the electrodes (e.g., first electrode 3 and second electrode 4). Thus, the total capacitance C 总计 can be viewed as the sum of the photo-capacitance C 光电 due to the trapped states and the dark (or geometric) capacitance C 暗 due to the spatial separation and shape of the electrodes.

[0128] C 总计 = C 光电 + C 暗 (2)

[0129] The extra capacitance C 光电 can be measured in a variety of ways, for example, a passive capacitor (photo-capacitor 1), a transistor, a diode, or any other suitable circuit form of device configuration, such as those adapted from the touch panel industry. Examples of implementation architectures are discussed below.

[0130] In terms of frequency response, the useful signal (i.e., C 光电 ) can be acquired at low frequencies, for example, in the hundreds of hertz, which is still well above the frequency range in which noise from electrostatic discharge, power supply noise, or any other form of low frequency noise can exist. As the frequency increases, for example, beyond several kilohertz, the extra capacitance C 光电 may become difficult to measure, or completely disappear due to the vanishing trapping emission process.

[0131] — Material Considerations —

[0132] There are a variety of disordered materials in the flat panel industry that can be considered for use as the photovoltaic capacitor layer 2 of the photovoltaic capacitor sensor. Suitable materials do not include indium tin oxide, which is used as a passive transparent conductor.

[0133] Disordered materials are commonly used as active layers in thin film transistors (TFTs), for example hydrogenated amorphous silicon (a-Si:H), which we use here as an example, secondly various organic semiconductors, and most recently amorphous semiconductor oxides, for example indium gallium zinc oxide (IGZO).

[0134] For example, a-Si:H is widely used in solar cells, photodiodes for visible light detection, and has been a conventional material used in thin film transistor (TFT) switches forming the basis of active matrix liquid crystal displays (LCDs) or active matrix organic light emitting diode (AMOLED) displays. In particular, a-Si:H material is highly disordered, resulting in a large concentration of distributed trap states, in fact typically three to four orders of magnitude higher than amorphous oxide semiconductor (AOS) counterparts. However, a-Si:H is a low bandgap material and is a good absorber of visible light radiation (absorption peaks in the green light) as well as the lower energy near infrared. In contrast, AOS counterparts are high bandgap materials and are typically transparent to visible light (absorption peaks in deep blue and ultraviolet), but do show absorption in the near infrared, though somewhat weakly, sufficient to produce a photovoltaic capacitor response.

[0135] In contrast to the working principle of photodetectors (e.g. photodiodes) and phototransistors that rely on the generation of a photocurrent when the material is illuminated with visible light, the response of the material to lower energy (longer wavelength) radiation is not due to a photocurrent but due to a photovoltaic capacitor, not trapped charge but (charge trapping) disorder properties produce trap states, even for low energy radiation, providing sufficient absorption. The charge trapping release process can accept a frequency of the stimulus signal used to measure the capacitance, for example up to several kilohertz.

[0136] — Electrodes of the photovoltaic capacitor —

[0137] The first and second electrodes 3, 4 used to form the photovoltaic capacitor 1 are not particularly limited, provided that at least some of the incident light is allowed to reach the photovoltaic capacitor layer 2.

[0138] For example, reference is also made to Figures 2A to 2I , which shows a range of possible electrode types.

[0139] Reference is made in particular to Figure 2A , which shows a mesh electrode 5.

[0140] The mesh electrode 5 takes the form of a conductive grid 6 formed from, for example, horizontal and vertical lines, leaving an array of gaps 7 through which light can reach the photovoltaic capacitor layer 2. The conductive grid 6 can be formed from metal or any other conductive material that can be processed to form the grid 6. Either or both of the first electrode 3 and the second electrode 4 can take the form of the mesh electrode 5.

[0141] Referring in particular to Figure 1 1, a frame electrode 8 is shown. Figure 2B

[0142] The frame electrode 8 takes the form of a conductive strip 9 that extends around the perimeter of the photovoltaic capacitor 1, leaving an opening 10 through which light can reach the photovoltaic capacitor layer 2. The conductive strip 9 can be formed from metal or any other conductive material that can be processed to form the strip 9. Either or both of the first electrode 3 and the second electrode 4 can take the form of the frame electrode 8.

[0143] Referring in particular to Figure 12, an interdigital electrode 1 1 is shown. Figure 2C

[0144] The interdigital electrode 1 1 takes the form of a first conductor 12 having elongate regions that cross with elongate regions of a second conductor 13 to leave a serpentine gap 14. The conductors 12, 13 can be formed from metal or any other conductive material that can be processed to form the conductors 12, 13. The first conductor 12 and the second conductor 13 can be connected to each other to form either the first electrode 3 or the second electrode 4.

[0145] Alternatively, the first conductor 12 can provide the first electrode 3, the second conductor 13 can provide the second electrode 4, and the photovoltaic capacitor material 2 can fill the serpentine gap 14 to form a photovoltaic capacitor having a planar structure rather than the layered structure of the photovoltaic capacitor 1.

[0146] Referring in particular to Figure 13, a serpentine electrode 15 is shown. Figure 2D

[0147] The serpentine electrode 15 takes the form of a conductive track 16 that follows a serpentine path, leaving an opening 17 between parallel sections of the conductive track 16 through which light can reach the photovoltaic capacitor layer 2. The conductive track 16 can be formed from metal or any other conductive material that can be processed to form the conductive track 16. Either or both of the first electrode 3 and the second electrode 4 can take the form of the serpentine electrode 15.

[0148] Referring in particular to Figure 14, a nanowire mat electrode 18 is shown. Figure 2E

[0149] ​​​​The nanowire mat electrode 18 takes the form of a mat of conductive nanowires 19 at a density sufficient to provide conduction through the nanowire mat electrode 18 without being so dense and / or thick as to block light from reaching the photovoltaic capacitive layer 2. The conductive nanowires 19 can be metallic nanowires, carbon nanotubes (single-walled or multi-walled) or any other suitable conductive nanowires. Either or both of the first and second electrodes 3, 4 can take the form of a nanowire mat electrode 18.

[0150] Referring in particular to Figure 1 1, Figure 2F a columnar structure electrode 20 is shown.

[0151] The columnar structure electrode 20 takes the form of a transparent conductive material that is patterned into an array of regular or irregular rods / poles / columns 21. Any transparent conductive material can be used, such as indium tin oxide (ITO). Either or both of the first and second electrodes 3, 4 can take the form of a columnar structure electrode 20. Capacitance can be increased if the columns 21 of the first and second electrodes 3, 4 extend towards each other so as to interpenetrate.

[0152] Referring in particular to Figure 1 1, Figure 2G a transparent electrode 22 is shown.

[0153] The transparent electrode 22 takes the form of a continuous region 23 of transparent conductive material, such as ITO. Either or both of the first and second electrodes 3, 4 can take the form of a transparent electrode 22.

[0154] Referring in particular to Figure 1 1, Figure 2H an opaque electrode 24 is shown.

[0155] The opaque electrode 24 takes the form of a continuous region 25 of opaque conductive material, such as a metal layer. In some examples, either of the first and second electrodes 3, 4 that is further from the pattern being measured can take the form of an opaque electrode, while the other of the pair of electrodes takes the form of an electrode that allows light to reach the photovoltaic capacitive material 2. Alternatively, the opaque electrode 24 can be very thin so that some light is transmitted through to the photovoltaic capacitive material 2.

[0156] Referring in particular to Figure 1 1, Figure 2I a porous electrode 26 is shown.

[0157] The porous electrode 26 takes the form of a porous conductive layer 27 that includes a fractional area of voids 28 through which light can reach the photovoltaic capacitive layer 2. The porous conductive layer 27 can be formed from a metal or any other conductive material that can be processed to form the porous conductive layer 27. Either or both of the first and second electrodes 3, 4 can take the form of a porous electrode 26.

[0158] Opto-capacitance sensor

[0159] Also refer to Figure 3 The photocapacitive sensor 29 is shown.

[0160] The photocapacitive sensor 29 includes an input surface 30, an array 36 of one or more light sources 31 and photocapacitors 32. Figure 4 The input surface 30 is provided by a transparent layer 33, which is formed, for example, of glass or a transparent plastic such as polyethylene terephthalate (PET) or polycarbonate (PC). The input surface 30 is the side of the transparent layer 33 facing away from the light source 31, and the transparent layer 33 has a second side 34 facing the light source 31. One or more light sources 31 are arranged to illuminate a portion 35 of the input surface 33 with emitted light 37. Figure 14 (That is, through transparent layer 33).

[0161] Also refer to Figure 4 The photocapacitors 32 are arranged in an array 36, for example, as shown in the image. Figure 4 The diagram shows a two-dimensional Cartesian array. Array 36 may include N rows and M columns of photocapacitors 32, where N and M are each integers greater than or equal to 2, and N and M may be equal or different. Let the capacitance of the photocapacitor 32 corresponding to the nth row and mth column of the N rows be denoted as C. nm Unless otherwise stated, references to photocapacitor 32,C are made. nm It should be assumed to refer to the contribution C of the photocapacitance. 光电 Instead of geometric contribution C 暗 Assume that the geometric contribution C of all photocapacitors 32 is... 暗 Similarly, any minor differences will be considered during the calibration of the photocapacitive sensor 29. The array 36 of the photocapacitors 32 is arranged to receive reflected light 38, which corresponds to emitted light 37 emitted from the irradiated portion 35 of the input surface 30. Figure 14 The reflection of an object 39 in contact with or near it. An array 36 of photocapacitors 32 is configured to detect the reflection pattern of the object 39.

[0162] exist Figure 3 In this context, the reflective pattern is shown as corresponding skin ridges, such as those of a fingerprint (including a thumbprint). This is an example of a reflective pattern formed by the unevenness (height) of the surface of object 39. However, the reflective patterns used for detection using photocapacitive sensor 29 are not limited to those generated by the unevenness of the surface of object 39. Generally, photocapacitive sensor 29 can be used to detect reflective patterns, albedo patterns, color patterns, or any other pattern form of object 39 capable of producing spatially varying reflectivity patterns. In particular, the detection of human skin ridges is not limited to fingerprints (including thumbprints) but can also be applied to palm prints or any other part of the body with unique skin ridge and groove patterns.

[0163] The pitch (or spacing) of the photocapacitors 32 within the array 36 should be configured to provide sufficient spatial resolution to resolve the reflection pattern of the object 39 being measured. In the example of a fingerprint measurement shown, the pitch of the rows and columns of the photocapacitors 32 should be small enough to be able to detect the ridges of a human finger, for example the ridges forming a fingerprint. However, in general, the pitch or spacing between the photocapacitors 32 forming the array 36 can be customized for the desired application, and can be less than 1 mm, less than 0.5 mm, equal to the pixel spacing in an associated display screen, etc. Figure 3 and Figure 4 In the example of a fingerprint measurement shown, the pitch of the rows and columns of the photocapacitors 32 should be small enough to be able to detect the ridges of a human finger, for example the ridges forming a fingerprint. However, in general, the pitch or spacing between the photocapacitors 32 forming the array 36 can be customized for the desired application, and can be less than 1 mm, less than 0.5 mm, equal to the pixel spacing in an associated display screen, etc.

[0164] Each photocapacitor 32 includes a layer of photocapacitive material 2 as described above, and can have the structure of the photocapacitor 1. Optionally, as described further below, each photocapacitor 32 can have a structure similar to a thin film transistor (TFT), except that the source and drain are shorted (). Figure 19 The layer of photcapacitive material 2 of each photocapacitor 32 can include or be formed of a disordered, crystalline or polycrystalline material so as to include in the bandgap of the material a trap state capable of absorbing sub-bandgap photon energy. The photcapacitive material 2 of each photocapacitor 32 can include or be formed of one or more of amorphous silicon, amorphous semiconductor oxide, organic material, etc.

[0165] The photocapacitive sensor 29 can be implemented as a passive sensor and / or as part of a passive sensing layer (not shown). In the example shown, the photocapacitive sensor 1 is implemented as part of an active sensing layer 40. Figure 4

[0166] The active sensing layer 40 includes a number M of transmission lines 41, each connected to a respective signal source 42. The active sensing layer 40 also includes a number N of receiving lines 43, each connected to a respective detector circuit 44. The photocapacitors 32C nm The mth transmission line 41 of the M transmission lines 41 is connected to the nth receiving line 43 of the N receiving lines 43. In use, the array 36 is scanned by exciting the transmission lines 41 one at a time with a time-varying signal, while using the respective detector circuits 44 to detect the capacitance C mn of the connected photocapacitors 32 from the receiving lines 43. The detection can be based on the charge stored by each photocapacitor 32, the phase difference of the time-varying signal between the transmission lines 41 and the receiving lines 43, or any other technique for capacitance measurement known in the art. For example, if the mth transmission line 41 is excited with a time-varying signal, the capacitances C m1 , C m2 ,..., C mN ​followed by excitation of the (m+1)th transmission line to measure the next set of photocapacitors 32.

[0167] In other examples, a single signal source 42 can be connected to each of the transmission lines 41 using a multiplexer (not shown), or a fewer number of signal sources 42 than M can be connected to multiple sets of transmission lines 41 using a corresponding number of multiplexers (not shown). In some examples, a single detector circuit 44 can be connected to each of the reception lines 43 using a multiplexer (not shown), or a fewer number of detector circuits 44 than M can be connected to multiple sets of reception lines 43 using a corresponding number of multiplexers (not shown).

[0168] In Figure 3 The example of a photocapacitive sensor 29 shown in Fig. 1 has an array 36 of photocapacitors 32 disposed between one or more light sources 31 and the input surface 30. As a result, in addition to the reflected light 38, the emitted light 37 can also impinge on the photocapacitors 32. There are a number of possible ways to mitigate this situation and significantly limit the detection sensitivity to changes in the photocapacitive C mn component of the photocapacitor C 光电 .

[0169] A first approach is to simply include the photocapacitance from the emitted light 37 in the baseline capacitance C 基线 , which includes the geometrical contribution C 暗 of each photocapacitor 32. For example, if the photocapacitive contribution C 光电 is split into a contribution C 发射 from the emitted light 37 and a contribution C 反射 from the reflected light 38, the desired signal C 反射 can be obtained as follows:

[0170] C 反射 = C 总计 - C 基线 (3)

[0171] where the baseline capacitance C 基线 is:

[0172] C 基线 = C 发射 + C 基线 (4)

[0173] This approach would be easy to implement in existing capacitive measurement systems, such as for capacitive touch, as these systems typically only focus on changes in capacitance and not absolute values.

[0174] A second method of shielding the effects of emitted light 37 on the photoelectric capacitors 32 is to use multiple directional light sources 31 and arrange the light sources 31 in the gaps between the photoelectric capacitors 32 to emit light 37 toward the input surface 30. This interleaved arrangement (i.e., an interpenetrating array of photoelectric capacitors 32 and light sources 31) can minimize the amount of emitted light 37 that impinges on the photoelectric capacitors 32 while still illuminating the input surface 30.

[0175] Another method of shielding the effects of emitted light 37 on the photoelectric capacitors 32 is to use an optional patterned light-attenuating layer 45 disposed between the photoelectric capacitors 32 and the light sources 31. The light-attenuating layer 45 is configured to shield the photoelectric capacitors 32 from direct illumination by emitted light 37 from one or more light sources 31 in at least the wavelength range to which the photoelectric capacitors 32 are sensitive. For example, the light-attenuating layer 45 can include gaps 46 corresponding to the spaces between the photoelectric capacitors 32 that form the array 36. The light-attenuating layer 45 can be opaque and can substantially or completely block emitted light 37. Alternatively, the light-attenuating layer 45 can selectively block light and can take the form of a light filter configured to block light in the wavelength range to which the photoelectric capacitors 32 are sensitive. In a further alternative, if the emitted light 37 is polarized, the light-attenuating layer 45 can be a polarizer that blocks polarized emitted light 37.

[0176] As shown in Figure 3 , the light-attenuating layer 45 can be a separate layer from the photoelectric capacitors 32. However, in some examples, the light-attenuating layer 45 can be integrated with each photoelectric capacitor 32. For example, the lowermost portions of the first and second electrodes 3 and 4 can be opaque electrodes 24 or electrodes patterned as polarizers.

[0177] The photoelectric capacitors 32 need not be disposed between the light sources 31 and the input surface 30.

[0178] For example, also referring to Figure 5 , a second photoelectric capacitive sensor 47 is shown.

[0179] The second photoelectric capacitive sensor 47 is identical to the photoelectric capacitive sensor 29 (hereinafter referred to as the “first” photoelectric capacitive sensor 29), except that the one or more light sources 31 are directional and emit light 37 toward the input surface 30, and the one or more light sources 31 are disposed (vertically, i.e., along the axis z as shown) between the array 36 of photoelectric capacitors 32 and the input surface 30.

[0180] For example, the one or more light sources 31 can comprise a plurality of light sources 31 arranged over the gaps between the photo-capacitors 32 to form an interdigitated array (or, for example, a single large area emitter with gaps corresponding to the photo-capacitors 32). In this way, light reflected from the pattern of the object 39 can reach the photo-capacitors 32 through the gaps between the light sources 31. Alternatively, the one or more light sources 31 can laterally overlap (or completely cover) the underlying photo-capacitors 32 if the light sources 31 are transparent to the reflected light 38.

[0181] In another example, the photo-capacitors 32 and the directional light sources 31 can be substantially coplanar.

[0182] The photo-capacitive sensors 29, 47 can be implemented as part of a button, touchpad, touch panel, touch screen, or the like. One advantage of the photo-capacitive sensors 29, 47 is that they can be operable even if the input surface 30 is wetted and / or submerged by water or any other fluid, as long as the fluid is transparent at the wavelength emitted by the light sources 31 and the photo-capacitors 32 are sensitive to it.

[0183] The one or more light sources 31 are not particularly limited and can take the form of, for example, a single large area emitter such as a light emitting diode (LED) or an organic light emitting diode (OLED). Alternatively, the one or more light sources 31 can form an array of light emitters of a single type (e.g., LEDs or OLEDs), or a sub-pixel array, each sub-pixel comprising two or more different types (e.g., colors) of light emitters. In some examples, the light sources 31 can be provided by one or more pixels or sub-pixels of a display device.

[0184] Some or all of the one or more light sources 31 can take the form of infrared (IR) emitters, such as IR LEDs or IR OLEDs. The IR emitters can correspond to a peak emission in the range of between 800 nm and 2,500 nm, inclusive. Some or all of the one or more light sources 31 can take the form of emitters selected from red, green, and blue emitters, such as LEDs or OLEDs. A sub-pixel can comprise, for example, a red light source 31, a green light source 31, and a blue light source 31.

[0185] The photo-capacitive sensors 29, 47 can optionally comprise one or more conductive traces (not shown) for making projected capacitance measurements. Alternatively, the electrodes defining the photo-capacitors 32 can also be used to make capacitance touch measurements sequentially (time-division multiplexed) or simultaneously with the photo-capacitive measurements.

[0186] Integration with display screen

[0187] While the opto-capacitive sensors 29, 47 can be used as standalone sensors for measuring the reflective pattern of the object 39, the opto-capacitive sensors 29, 47 can also be integrated with and in various locations in a wide variety of different display types. The cover glass of such integrated displays can provide the input surface 30.

[0188] For example, the opto-capacitive sensors 29, 47 can be embedded in an active matrix liquid crystal display (AMLCD) and / or active matrix OLED (AMOLED) architecture. The opto-capacitive sensors 29, 47 can be implemented in existing capacitive touch systems that also rely on changes in capacitance due to the principle that the capacitance changes upon illumination. The amorphous layer providing the opto-capacitive layer 2 can be integrated as a passive dielectric layer in any existing capacitive touch panel, or in other examples can remain as a separate layer in a separate readout aspect, but using the same readout infrastructure.

[0189] — Under-display architecture —

[0190] The opto-capacitive sensors 29, 47 can be placed under the pixel layer of a display, and each opto-capacitor 32 can be configured as a simple passive capacitor that can have a standard readout fed to a standard touch controller (not shown) connected to the display. The touch controller (not shown) can read out the array 36 of opto-capacitors 32 in a separate time period of the capacitive touch measurement.

[0191] For example, referring to Figure 6 , a first under-display stack 48 is shown.

[0192] The first under-display stack 48 includes the array 36 of opto-capacitors 32, a collimating layer 50, a TFT layer 51, a light emitting layer 52 (providing the light source 31), a polarizing layer 53, an optional capacitive touch electrode layer 54, and a cover glass 55 stacked in the direction between a substrate 49 and the input surface 30. The layers 36, 50, 51, 52, 53, 54 are supported on the substrate 49 and are bonded to the cover glass 55 with an optical clear adhesive (OCA) 56 layer. The first under-display stack 48 generally corresponds to a display panel of, for example, LED or OLED type, and the like.

[0193] The collimating layer 50 is a light control film (LCF), also known as a light collimating film, in the form of an optical film configured to adjust the directionality of transmitted light. The collimating layer 50 can take the form of, for example, a microlens array, pinhole array, or grid of optical waveguides. The collimating layer 50 provides maximum transmission at a predetermined angle of incidence relative to the image plane and image cutoff or blackout along a given polar coordinate as required by the application. The TFT layer 51 controls the illumination of the pixels forming the light emission layer 52. The light emission layer 52 is formed of pixels or sub-pixels of light emitters in the form of LEDs, OLEDs, or uLEDs. The light emission layer 52 can take the form of a standard RGB pixel display, or alternatively, each sub-pixel can include red, green, blue, and IR emitters.

[0194] The cover glass 55 can be any suitable material for a touch screen display, such as glass, transparent polymer, etc.

[0195] Referring also to Figure 7 , a second display underlay 57 is shown.

[0196] The second 62 display underlay 57 includes an array 36 of photogalvanic capacitors 32 stacked in a direction between the substrate 49 and the input surface 30, a backlight layer 58 (providing light sources 31), an optical layer 59, a TFT layer, a liquid crystal (LC) layer 60, a color filter (CF) and black matrix (BM) layer 61, an optional capacitive touch electrode layer 54, an OCA, and a polarizer layer 62, and a cover glass 55. The second 62 display underlay 57 generally corresponds to, for example, a backlit LCD panel or the like.

[0197] The TFT layer 51 controls the switching of pixels defined by the LC layer 60 in conjunction with the color filters and BM layer 61. The backlight layer 58 provides the light sources 31 and emitted light 37.

[0198] In either of the first display underlay 48 and the second display underlay 57, the touch electrode layer 54 is optional and can be omitted. When present, the touch electrode layer 54 can be used to detect user touch.

[0199] — Display over (or battery on) architecture—

[0200] Referring also to Figure 8 , a first display over (or “battery on”) layup 63 is shown.

[0201] The first battery on layup 63 is the same as the first display underlay 48, except that the array 36 of photogalvanic capacitors 32 is located between the polarizer 53 (as shown above the optional capacitive touch electrode 54) and the OCA layer 56, rather than between the substrate 49 and the TFT layer 51. Optionally, the light attenuation layer 45 can be included anywhere between the array 36 and the light emission layer 52.

[0202] The first battery-mounted stack 63 is reminiscent of a standard on-cell capacitive touch architecture, and the array 36 can be integrated into the capacitive touch stack and read out using the same readout technology and touch controller (not shown) as for capacitive touch. Preferably, the capacitive touch and photocapacitance signals are not mixed, but time-division multiplexed for readout. In this way, photocapacitance measurements can be integrated using the same readout infrastructure as for capacitive touch, thus simplifying the electronics. Alternatively, photocapacitance measurements can have a separate readout electronics from the capacitive touch functionality.

[0203] Also refer to Figure 9 The image shows the stack 65 above the second display (or "on the battery").

[0204] The second battery upper stack 64 is the same as the second display lower stack 57, except that the array 36 of photocapacitors 32 is located between the CF and BM layers 61 (as shown above the optional capacitive touch electrode 54) and the OCA and polarizer layers 62, rather than between the substrate 49 and the backlight layer 58. Optionally, the substrate 49 can be configured as a reflector 65. Optionally, the light attenuation layer 45 can be included at any location between the array 36 and the backlight layer 58.

[0205] The second battery superlayer 64 has advantages over the first battery superlayer in terms of integration with capacitive touch.

[0206] —In-display (or in-battery) architecture—

[0207] Also refer to Figure 10 This shows the stack 66 within the first display (or battery).

[0208] The first battery inner stack 66 is the same as the first display lower stack 48 or the first battery upper stack 63, except that the array 36 of the photocapacitor 32 is integrated with the TFT layer 51 instead of being a separate layer. In this way, the photocapacitor 32 can use the same amorphous silicon layer as that defining the TFT to provide the photocapacitor material layer 2, thereby simplifying manufacturing and reducing the number of layers. Even further integration is possible, as the TFT structure can be modified to provide the photocapacitor 32 by shorting the source and drain electrodes together. Figure 19 In use, the corresponding photocapacitance C can then be read between the short-circuited source and drain electrodes and the gate electrode. 光电 .

[0209] A smartphone running on a low temperature polysilicon (LTPS) transistor for the TFT layer 51 can already contain a-Si:H used as the photocapacitive material layer 2. In fact, LTPS is typically formed from laser crystallized a-Si:H. Thus, fabricating the array 36 and the TFT layer 51 from a single material layer can synergistically reduce the number of times and complexity of manufacturing a display with integrated photocapacitive sensors.

[0210] The readout of the capacitance from the array 36 will be the same as any touch panel described above, where the capacitance is read out by a touch controller (not shown) during a time period separate from the standard capacitive touch, e.g. by appropriate logic gating.

[0211] Referring also to Figure 10 , a second in-cell stack 67 within the second display (or battery) is shown.

[0212] The second in-cell stack 67 is the same as the second under-display stack 57 or the second on-battery stack 64, except that the array 36 of photocapacitors 32 is integrated with the TFT layer 51, rather than as a separate layer. Optionally, a light attenuation layer 45 can be included between the TFT and photocapacitor layers 36, 51 and the backlight layer 58.

[0213] The second in-cell stack 67 provides similar advantages as the first in-cell stack 66, but for LC display architectures.

[0214] — On-display (or on-battery) architectures —

[0215] Referring also to Figure 12 , a third on-battery stack 68 is shown.

[0216] The third on-battery stack 68 is the same as the first on-battery stack 63, except that the array 36 is moved between the light emission layer 52 and the polarizer layer 53, rather than between the polarizer layer 53 and the cover glass 55. Optionally, a light attenuation layer 45 can be included between the array 36 and the light emission layer 52.

[0217] Referring also to Figure 13 , a fourth on-battery stack 69 is shown.

[0218] The fourth on-battery stack 69 is the same as the third on-battery stack 64, except that the array 36 is moved between the LC layer 60 and the CF and BM layers 61, rather than between the CF and BM layers 61 and the cover glass 55. Optionally, a light attenuation layer 45 can be included between the array 36 and the backlight layer 58.

[0219] For the third and fourth cell-on-stack 68, 69, the capacitive touch electrode 54 is now located above the light emission layer 52 and the LC layer 60, respectively. The photocapacitive layer 2 of the array 36 of photogalvanic capacitors 32 can be made of the same or equivalent material as the TFT layer 51, but its implementation can take the form of a passive capacitor (see Figure 1 ).

[0220] Although a series of different display stacks have been described, the use of the photocapacitive sensor 29, 47 according to the present specification is not limited to the explicitly described display stacks, and the photocapacitive sensor 29, 47 can be added between the layers of any type of display architecture (or integrated with compatible layers).

[0221] Range of illumination portion

[0222] The irradiation portion 35( Figure 14 ) generally corresponds to the extent of the array 36 of photogalvanic capacitors 32. For example, in a display, a display pixel can substantially irradiate the entire cover glass 55 providing the input surface 30. However, the irradiation portion 35 is considered to be the portion of the input surface 30 that is overlaid by the array 36 of photogalvanic capacitors 32.

[0223] Reference is also made to Figure 14 , a first display layout 70 is shown.

[0224] The device 71 comprises a display area 72. In the first display layout 70, the irradiation portion 35 corresponding to the photocapacitive sensor 29, 47 corresponds to a first zone 73 of the display area 72. In the Figure 14 example shown, the first zone 73 extends substantially along the edges of the display area 72. However, the shape, relative size and relative position of the first zone 73 within the display area 72 are not limited to the specific illustration in Figure 14 . For example, the first zone 73 can be located in the centre of the display area 72.

[0225] In this way, the photocapacitive sensor 29, 47 can be provided to a zone 73 of the display of a device 71, such as a mobile phone or tablet computer, which can sense a user’s fingerprint (including a thumbprint). This can allow the use of fingerprint authentication to, for example, unlock the mobile phone and / or authorize transactions, without having to sacrifice any display area 72 to a separate button or reader.

[0226] Reference is also made to Figure 15 , a second display layout 74 is shown.

[0227] The second display layout 74 is the same as the first display layout 70 and further includes an additional photo-capacitive sensor 29, 47 having an illuminated portion 35 corresponding to a second zone 75 of the display area 72 different from the first zone 73. In Figure 15 In the illustrated example, the first zone 73 extends along a first edge of the display area 72 and the second zone 75 extends along a second, opposite edge of the display area 72. However, any two shapes, positions, and relative sizes of the different zones 73, 75 can be defined according to the intended application.

[0228] Referring also to Figure 16 a third display layout 76 is shown.

[0229] The third display layout 76 is the same as the first display layout 70, except that the first zone 73 extends around the entire periphery of the display area 72.

[0230] However, the illuminated portion 35 is not limited to the zones 73, 75 of the display area 72 and, in some examples, the illuminated portion 35 can extend coextensively with the display area 72. For example, referring also to Figure 17 a fourth display layout 77 is shown in which the illuminated portion 35 extends coextensively with the display area 72.

[0231] Examples of integrating opto-capacitors in TFT layers

[0232] Referring also to Figure 18 and Figure 19 a specific example 78 of the second in-cell stack 67 will be described to provide one exemplary method of integrating the array 36 of photo-capacitors 32 into the TFT layer 51.

[0233] In the illustrated example, the backlight layer 58 includes a mixture of white LEDs 79 (or OLEDs) and IR LEDs 80 (or OLEDs). Stacked between the backlight layer 58 and the TFT layer 51 are a backlight diffusion layer 81, an optical film layer 82, a first polarizing layer 83, and a patterned conductive layer 84 providing electrical connection to one side of the TFT layer 51.

[0234] The TFT layer 51 includes blue pixels 85 corresponding to blue color filters 86 of the CF and BM layers 61, green pixels 87 corresponding to green color filters 88 of the CF and BM layers 61, red pixels 89 corresponding to red color filters 90 of the CF and BM layers 61, and TFT integrated photo-capacitors 91.

[0235] Referring specifically to Figure 19Each TFT-integrated photo-capacitor 91 includes a dielectric layer 92 supporting a semiconductor region 93 having photo-capacitive properties. A source electrode 94 is deposited on one side of the semiconductor region 93, and a drain electrode 95 is deposited on the opposite side to define a channel between the source electrode 94 and the drain electrode 95. A gate electrode 96 is deposited on the side of the dielectric 92 opposite the semiconductor region 93. A first conductive trace 97 is connected to the gate electrode 96, and a second conductive trace 98 is connected to both the source electrode 94 and the drain electrode 95. Thus, the source electrode 94 and the drain electrode 95 are shorted together. The capacitance C is measured between the gate electrode 96 and the coupled source electrode 94 and drain electrode 95. 光电

[0236] In this way, the TFT-integrated photo-capacitor 91 can have the same structure as the pixels defining the TFTs 85, 87, 89, requiring only a change in the layout of the conductive traces connected to the TFT layer 51. This allows the TFT-integrated photo-capacitor 91 to be added almost seamlessly into the manufacture of a conventional display TFT layer.

[0237] Each of the blue pixel 85, the green pixel 87, and the red pixel 89 has a conventional configuration for a pixel of a backlit LCD display.

[0238] The CF and BM layer 61 also includes a conventional black matrix (BM) material 99. Preferably, the BM material 99 is transparent to the IR wavelengths emitted by the IR LED / OLED 80, so that the emitted light 37 can reach the input surface 30 and the object 39, and the reflected light 38 can reach the TFT-integrated photo-capacitor 91. Additionally or alternatively, the BM material 99 can include additional apertures (not shown) to allow the emitted light 37 and the reflected light 38 to pass, for example, between the input surface 30 and the TFT-integrated photo-capacitor 91.

[0239] Stacked in order between the CF and BM layer 61 and the cover glass 55 are a second polarizing layer 100, an optically clear adhesive layer 101, and a third polarizing layer 102.

[0240] Device comprising opto-capacitance sensor

[0241] Reference is also made to Figure 20 , which shows a system 110.

[0242] The system includes a device 111, which includes the photo-capacitance sensor 29, 47 and a controller 112.

[0243] The controller 112 is connected to the photo-capacitance sensor 29, 47 via a link 113, and the controller 112 is configured to measure the capacitance C mn of the array 36 of photo-capacitors 32.

[0244] With respect to the examples described above, the controller 112 can be a touch controller, and the system 110 can further include a display beneath, above, or integrated with the photocapacitive sensors 29, 47. In other words, the system 110 and device 111 can be part of a larger apparatus such as a cell phone, tablet computer, etc.

[0245] Alternatively, the system 110 can form part of an access control system of an apparatus other than a cell phone or tablet computer, as described below.

[0246] The controller 112 includes one or more processors 114, volatile memory 115, and non-volatile storage 116. The non-volatile storage 116 stores program code 117 for controlling the controller to measure the capacitance C mn of the array 36 of photocapacitors 32, and to perform other functions described herein. The controller 112 will also include an output for controlling the signal source 42, or can directly output the time-varying signal to directly measure the capacitance C mn . Similarly, the controller 112 can also include one or more detector circuits 44. In some examples, an apparatus such as a cell phone, tablet computer, etc. incorporating the photocapacitive sensors 29, 47 can provide some or all of the necessary data processing capability, volatile and non-volatile storage.

[0247] Optionally, the controller 112 can store a reference frame 118 of measured capacitances C 基线 corresponding to the array 36 of photocapacitors 32 when the one or more light sources are illuminated without an object 39 above or in contact with the input surface. The controller can be configured to subtract the reference frame 118 from the capacitances C mn measured from the array 36 of photocapacitors 32 in order to implement equation (3) as described above.

[0248] Optionally, the controller 112 can additionally be configured to control the emission of light from the one or more light sources 31 of the photocapacitive sensors 29, 47. In such examples, to conserve power, the controller 112 can only illuminate the light sources 31 when it is desired to measure the capacitances C mn of the array 36 of photocapacitors 32. For example, if the light sources 31 take the form of IR emitters integrated into an RGB display, it can not be necessary to illuminate the IR emitters at all times. If the display includes capacitive touch sensing functionality, the controller 112 can illuminate the IR emitters (light sources 31) in response to capacitive touch detection in order to measure the fingerprint pattern of a person touching the input surface 30.

[0249] One possible advantage of opto-capacitors for fingerprint (or other skin pattern) sensing compared to traditional capacitive fingerprint sensing is that it is possible to check whether the detected fingerprint pattern corresponds to a live person. For example, traditional capacitive fingerprint sensing is based on electrical conductance and can be spoofed using a fake fingerprint pattern.

[0250] Using opto-capacitive sensors 29, 47 integrated with a display having red, green, blue, and IR emission capabilities, it is possible to check for the presence of oxyhemoglobin in the contacting object 39. For example, the controller 112 can only illuminate the red light sources 31 (pixels / sub-pixels) and measure the first set of capacitances C mn from the array 36. Then only the IR light sources 31 (pixels / sub-pixels) are illuminated and the second set of capacitances is measured from the array 36. By comparing the first and second sets of capacitances C mn , the controller 112 can determine the ratio of reflectivity at red and IR wavelengths, thereby distinguishing live human skin from a spoofed fingerprint pattern. It can be noted that the ratio of reflectivity at red and IR wavelengths can be determined using an aggregate measurement to improve accuracy, as only the pattern itself requires spatial resolution.

[0251] Once the controller 112 measures the pattern of capacitances C mn from the array 36 of opto-capacitors 32, the pattern can be compared to a set of one or more authorized patterns 119. Each authorized pattern 119 can correspond to, for example, the fingerprint of a person authorized to use a device or equipment associated with the system 110 or to enter an area associated with the system 110. The comparison by the controller 112 should not be sensitive to the relative rotation of the measured pattern of capacitances C mn . The authorized patterns 119 can be stored in a secure storage 120 that communicates with the controller 112 using a wired or wireless link 121. Alternatively, the authorized patterns 119 can be stored internally in the storage 116 of the controller 112. If the pattern of capacitances C mn measured using the array 36 matches any of the authorized patterns 119, the controller 112 outputs a signal to a device 123 associated with the opto-capacitive sensor 29, 47 using a wired or wireless link 122 indicating that an authorized user was detected.

[0252] When the system 110 is integrated as part of a cell phone, tablet computer, or other device (e.g., a printer or a piece of medical equipment), the entire process can be internal to the device (i.e., the device 123 can simply be the rest of the device that includes the system 110).

[0253] When implemented as a stand-alone device, the device 111 can be used as an access control device for the device 123, such as a printer, medical device, door, elevator control panel, motor vehicle, motorcycle, bicycle, construction equipment such as a bulldozer, trencher, excavator, and airplane, military equipment, and the like. Additionally or alternatively, the device 111 can be used as an access control device for a door or lock, providing access to a medicine cabinet, a hospital room such as a maternity ward and obstetrics ward, a hotel room door, a hotel back-of-house door, or any other room or space for which access is desired to be controlled.

[0254] modifications

[0255] It is to be understood that numerous modifications can be made to the above described embodiments. Such modifications can involve equivalent and other features that are known in the design and use of photo-capacitance sensors, biometric authentication sensors, and / or scanners for fingerprints and / or other unique patterns, and that can be used in place of, or in addition to, the features already described herein. Features of one embodiment can be replaced or supplemented by features of another embodiment.

[0256] Possible uses of the photo-capacitance sensors of the present specification for pattern detection can include, but are not limited to, multi-finger simultaneous scanning of a handprint for access to a cell phone; in-application and on-surface secure fingerprint recognition for secure applications implemented in general displays, HID devices. Other applications include engineering applications, such as proof of authorization at a service delivery point. Further applications include providing authoritative audit trails.

[0257] Still further applications include medical displays, computers, MRI or other diagnostic machines, or any other medical equipment (e.g., access to controls of medical devices only by authorized personnel), in-application authorization (e.g., printing of a prescription), audit trails, and the like.

[0258] The photo-capacitance sensors 29, 47 can be configured to allow for safety through gloves, for example, by using a wavelength that can be read through a thin surgical glove or other type of PPE glove.

[0259] The photo-capacitance sensors 29, 47 can be used in place of card, code, and / or key security in, for example, hospitals, laboratories, or any other facility requiring access control. The photo-capacitance sensors 29, 47 can be integrated directly into, for example, door handles, door push plates, locks, and the like.

[0260] Separate readout of projected capacitance and opto-capacitance

[0261] The above-described stacks 48, 57, 63, 64, 66, 67, 68, 69 can include dedicated electrodes 54 for projected capacitance measurements. As previously described, one option for such an arrangement is to include separate readout electronics for the photo-capacitance and capacitive touch functionality.

[0262] For example, reference is also made to Figure 21 a schematic diagram of the separate readout configuration 124 is shown.

[0263] The separate readout configuration 124 comprises a capacitive touch controller 125 coupled to the projected capacitive touch electrodes 126 and a photo-capacitance controller 127 coupled to the photo-capacitance sensors 29, 47. The photo-capacitance controller 127 is configured to measure the photo-capacitance of the array 36 of photo-capacitors 32, 91 forming the photo-capacitance sensors 29, 47. The capacitive touch controller 125 is configured for projected capacitive touch sensing using the projected capacitive touch electrodes 126, e.g. in the form of suitable conductive traces. The capacitive touch controller 125 provides drive signals 128 to the projected capacitive touch electrodes 126 and determines capacitances for detecting user interaction based on corresponding receive signals 129. Similarly, the photo-capacitance controller 127 provides drive signals 130 to the photo-capacitance sensors 29, 47 and corresponding receive signals 131 can be used to determine the reflection pattern, as described above.

[0264] The outputs and inputs of the capacitive touch controller 125 and / or the photo-capacitance controller 127 can be multiplexed to allow scanning a larger number of electrodes than the number of channels on the respective controller 125, 127.

[0265] The drive signals 128, 130 for the projected capacitive measurement and the photo-capacitance measurement can be different. For example, the time constant of the projected capacitive touch electrodes 127 (or the intersection between them) can be different from the time constant of the photo-capacitors 32. Moreover, advantageously, frequency division multiplexing of the drive signals 128, 130 for the projected capacitive measurement and the photo-capacitance measurement will reduce cross-talk between the two measurements.

[0266] The projected capacitive touch electrodes 126 can be in the form of the capacitive touch electrode layer 54 described above, for example. The separate readout configuration 124 can be used for the system 110 / device 111, in which case the photo-capacitance controller 127 can be in the form of the controller 112 described above. Likewise, the photo-capacitance controller 127 can be provided by any controller configured to measure the photo-capacitance of the photo-capacitance sensors 29, 47 described herein.

[0267] In some examples, the capacitive touch controller 125 and the photo-capacitance controller 127 can be provided by different channels of a single device. For example, the capacitive touch controller can comprise K number of channels, of which the first 1 to k can be dedicated to the projected capacitive measurement (providing the capacitive touch controller 125), while the remaining k+1 to K channels are dedicated to the photo-capacitance measurement (providing the photo-capacitance controller 127).

[0268] The capacitive touch controller 125 can be used for self-capacitance measurement or mutual capacitance measurement.

[0269] Time-division multiplexed readout of projected capacitance and opto-capacitance

[0270] It is not necessary to use separate electronics (or at least dedicated channels) for projected capacitance and photocapacitance measurements. Another option for the stacks 48, 57, 63, 64, 66, 67, 68, 69 (including a dedicated electrode 54 for projected capacitance measurement and a separate layer 36 for discrete photocapacitors 32, 91) is to use a single capacitive touch controller and time-division multiplex the measurements of projected capacitance and photocapacitance. In this way, photocapacitance measurements can be integrated using the same readout infrastructure as capacitive touch, thus simplifying the electronics.

[0271] For example, also refer to Figure 22A and Figure 22B This schematically illustrates the time-division multiplexing readout configuration 132.

[0272] The time-division multiplexing readout configuration 132 includes a controller 133 connected via a switch network 134 to the projected capacitive touch electrode 126 and photocapacitive sensors 29, 47. The controller 133 is configured to perform time-division multiplexing by controlling the switch network 134 to alternate between performing projected capacitive touch sensing and measuring photocapacitance from the photocapacitive sensors.

[0273] For details, please refer to the following: Figure 22B During a first time period, such as t0 to t1, t2 to t3, t4 to t5, etc., the switching network connects the controller 133 to the projected capacitive touch electrode 126. A second time period intersects with the first time period, such as t1 to t2, t3 to t4, t5 to t6, etc., during which the switching network connects the controller 133 to the photocapacitive sensors 29, 47 for photocapacitive measurement.

[0274] The projected capacitive touch electrode 126 can take the form of, for example, the capacitive touch electrode layer 54 described above. A time-division multiplexed readout configuration 132 can be used in system 110 / device 111, in which case the controller 133 can take the form of the controller 112 described above.

[0275] The switching network 134 may additionally provide multiplexing so that the controller 133 with K channels can scan more than K drive / sensor lines during the first projected capacitance measurement period t0 to t1, t2 to t3, t4 to t5, and / or scan more than K photocapacitors 32 during the second photocapacitance measurement period t1 to t2, t3 to t4, t5 to t6.

[0276] Combined readout of projected capacitance and opto-capacitance

[0277] As noted above, the electrodes defining the photoelectric capacitors 32, 91 can also be used to make capacitive touch measurements sequentially (time-division multiplexed) or simultaneously with photoelectric capacitive measurements. In such examples, the separate projective capacitive electrodes 54, 126 can be omitted, simplifying the sensor / display stack-up.

[0278] For example, referring also to Figure 23 , a combined readout configuration 135 is shown.

[0279] The combined readout configuration 135 includes a controller 136 and a photoelectric capacitive sensor 29, 47. In the combined readout configuration 135, the controller 136 measures the capacitance of each photoelectric capacitor 32, 91 two or more times and coordinates the light source 31 to obtain at least a pair of measurements, including a first measurement corresponding to illumination of the photoelectric capacitor 32 and a second measurement corresponding to a "dark" state in which the light source 31 under the interaction site is not illuminated.

[0280] The combined readout configuration 135 can be used in the system 110 / device 111, in which case the controller 136 can take the form of the controller 112 described above.

[0281] Any of the photoelectric capacitor 32, 91 structures described above can be used in the combined readout configuration 135, since any electrode defining a photoelectric capacitor 32, 91 will include a geometric component of the capacitance coupled to a user's finger and / or a conductive stylus, enabling touch sensing by projective capacitance.

[0282] However, the combined readout configuration 135 can also be applied to other configurations.

[0283] For example, referring also to Figures 24 to 26 , a structure and operation of an integrated touch and photoelectric capacitive sensor 137 (hereafter "third photoelectric capacitive sensor") is shown.

[0284] The third photoelectric capacitive sensor 137 is based on the understanding expressed above that a layer of photoelectric capacitive material 2 can be integrated as a passive dielectric layer in any existing capacitive touch panel.

[0285] The third photoelectric capacitive sensor 137 includes, for example, a number N of first electrodes 1381, 1382,..., 138 N which extend in a first direction x and are spaced apart in a second, different direction y. The third photoelectric capacitive sensor 137 also includes, for example, a number M of second electrodes 1391, 1392,..., 139 N, which extend in a second direction y and are spaced apart in a first direction x. A layer 140 of the opto-capacitive material 2 is provided between the first electrodes 138 and the second electrodes 139, such that each intersection of a first electrode 138 and a second electrode 139 provides an opto-capacitor 141 of an array 36 of third opto-capacitive sensors 137. For example, an n-th first electrode 138 of the N first electrodes n intersects with an m-th second electrode 139 of the M second electrodes m provides an opto-capacitor 141 n,m with a capacitance C n,m .

[0286] With particular reference Figure 26 , the layer 140 provides a dielectric of each opto-capacitor 140 n,m . When the opto-capacitive material 2 forming the layer 140 is illuminated, the dielectric constant changes, thereby modifying the distribution of electric field lines 142 between the first electrodes 138 n and the second electrodes 139 m . In this way, the capacitance C n,m can be geometrically coupled to a nearby conductive object (in the usual way of projected capacitance touch), which is also recorded by the responsive opto-capacitive component.

[0287] Any number of additional dielectric layers (not shown) can be inserted between the layer 140 and the first electrodes 138 and / or any number of additional dielectric layers (not shown) can be inserted between the layer 140 and the second electrodes 139.

[0288] The layer 140 of the opto-capacitive material 2 need not be provided between the first electrodes 138 and the second electrodes 139.

[0289] For example, also see Figure 27 , in an alternative configuration, the first electrodes 138 and the second electrodes 139 can instead be substantially co-planar / provided on the same surface. Such co-planar (or substantially co-planar) electrode configurations are known in the art of capacitance touch, using for example partial insulator patches that the electrodes 138, 139 intersect, and measuring the capacitance associated with the fringe field between the electrodes 138, 139 at the edges rather than the overlapping area (which is minimized). For example, diamond pattern electrodes for mutual capacitance touch sensing.

[0290] The first electrodes 138 and the second electrodes 139 are provided on or above the layer 140 of the opto-capacitive material 2, such that each intersection of a first and a second electrode provides an opto-capacitor of the array. As shown by the field lines 142 drawn in Figure 27 , the underlying layer 140 of the opto-capacitive material 2 will still interact with and modify the capacitance between co-planar electrodes.

[0291] Any number of additional dielectric layers (not shown) can be inserted between the layer 140 and the first and second electrodes 138, 139.

[0292] The third opto-capacitive sensor 137 can be disposed on (or integrated as part of) a display 143, such as an LCD, OLED, or any other type of display. A cover 144, such as a cover glass 55, can be adhered or otherwise secured over the third opto-capacitive sensor 137 using the third opto-capacitive sensor 137 to protect the electrodes 138, 139 and provide the input surface 30. For example, when the third opto-capacitive sensor 137 is overlaid on (or forms part of) the display 143, an optically clear adhesive 145 can be used to adhere the cover 144.

[0293] The first and second electrodes 138, 139 are not limited to being disposed on either side of the layer 140 of opto-capacitive material 2 or co-planar with the layer 140 of opto-capacitive material 2 and disposed thereon or thereabove. In general, the relative positions of the layer 140 relative to the first and second electrodes 138, 139 are limited only by the need to have the electric field lines connecting the first and second electrodes pass through the opto-capacitive material 2. For example, in a further modification of the third opto-capacitive, the first and second electrodes 138, 139 can be separated by a non-opto-capacitive dielectric layer (not shown), and one or a pair of layers 140 of opto-capacitive material 2 can be disposed above and / or below the first and second electrodes 138, 139. In other words, the layers can be stacked in the following order: a layer 140 of opto-capacitive material 2, the first electrode 138, a non-opto-capacitive dielectric layer (not shown), the second electrode 139, and optionally a second layer 140 of opto-capacitive material 2.

[0294] In an alternative modification, the first and second electrodes 138, 139 can be substantially co-planar and supported on a substrate, with the layer 140 of opto-capacitive material 2 being substantially co-planar with the first and second electrodes 138, 139 and patterned to fill the space between the electrodes 138, 139.

[0295] Reference will also be made to Figures 28 to 30B A method of using the combined readout configuration 135 will be described.

[0296] First, the controller 136 scans the third opto-capacitive sensor 137 in a conventional projected capacitance mode at, for example, a first frequency (or first set of frequencies). In the projected capacitance mode, fewer than all N first electrodes 138 and / or all M second electrodes 139 can be scanned. This is because the pitch of the electrodes 138, 139 for, for example, fingerprint sensing is on the order of 50 microns, while conventional projected capacitance touch can use a pitch on the order of 5 mm.

[0297] Thus, the controller 136 can measure the capacitance of at least a subset of the array 36 of photocapacitors 32, 91, 141. Alternatively, several first electrodes 138 can be grouped together and / or several second electrodes 139 can be grouped together for the purpose of projected capacitance sensing. In some examples, all electrodes 138, 139 can be used for projected capacitance sensing.

[0298] When a user interaction is detected, e.g. a finger 146 is pressed to the input surface 30, the controller 136 uses the projected capacitance data to determine an interaction zone 147 (dashed line in Figure 28 ).

[0299] Within a dark zone 148 (dotted line) delimited by the interaction zone 147 (which can be the entire interaction zone 147), the controller 136 deactivates all light sources 31, including the light sources dedicated to the photocapacitance measurements and any pixels of the underlying display 143. Reference is made in particular to Figure 29 , see e.g. times to ti and t2 to t3.

[0300] Without local illumination, the capacitance of each photocapacitor 32, 47, 141 is measured for each photocapacitor within a measurement zone 149 (which can be equal to the dark zone 148 and / or the interaction zone 147). Reference is made in particular to Figure 30A , a measurement of the geometric capacitance component C geo will be provided, without any contribution of the photocapacitance generated by light reflected from the input surface 30.

[0301] The controller 136 activates at least a subset of the light sources 31 corresponding to the measurement zone 149 (which can be equal to the dark zone 148 and / or the interaction zone 147). The total capacitance C 总计 of each photocapacitor 32, 47, 141 within the measurement zone 149 is then measured. Reference is made in particular to Figure 30B , each total capacitance C 总计 will exhibit a variation AC from the corresponding unilluminated (or dark) capacitance C geo , where AC = C 总计 - C geo , and this variation AC corresponds to the photocapacitance signal. The variation AC will lie in a range between a value C trans corresponding to a perfect transmission of light through the input surface 30 (i.e. the light passes through the layer 140 once) and another value C refl corresponding to a perfect reflection from the input surface 30 or an object immediately above it. It is important to note that the measured variation AC can be used to measure the reflection pattern of the object 39.

[0302] A subset of light sources 31 can include all light sources 31 in the measurement region 149, or can be limited to all light sources 31 of a particular color. For example, the display 143 can include red (R), green (G), and blue (B) pixels, and all pixels can be deactivated to measure the projected capacitance component C geo and then only the red (R) light sources are activated to measure the total capacitance C 总计 In some examples, different color light sources 31 (e.g., R, G, and B) provided by the display 143 can be illuminated sequentially to obtain color-specific photo-capacitance measurements, enabling color imaging of the object 39 (e.g., a user’s finger 146). In some examples, the display 143 can also include IR light sources (not shown) over at least one region, and the IR light sources can be reactivated only for the purpose of determining the photo-capacitance component AC. Imaging color, and in particular the addition of IR measurements, can allow detection of oxygenated human skin to prevent spoofing using, for example, a fingerprint image of a person. The measurements can be prolonged for a period long enough to detect a user’s pulse to provide additional security against spoofing.

[0303] The process of deactivating and activating the light sources 31 can be repeated any number of times in order to refine the photo-capacitance component AC, for example, by taking an average of the values measured during different time periods (e.g., ti to t2 and t3 to t4). Referring in particular to Figure 29 two cycles are shown, but any number of cycles can be used. When the light sources 31 include two or more colors and measurements are taken using two or more colors, the measurements can be taken one after the other, or separated by a time period in which all of the light sources 31 are deactivated.

[0304] Addressing scheme for combined readout configuration

[0305] The combined readout configuration 135 can be further understood by reference to some specific examples of addressing electrodes used for projected capacitance touch sensing and photo-capacitance measurements.

[0306] Referring also to Figure 31 a first addressing scheme 160 for the combined readout configuration 135 is shown.

[0307] The first addressing scheme 160 uses an example of the third photo-capacitance sensor 137, and the first electrode 138 and the second electrode 139 are used for both projected capacitance touch detection and photo-capacitance measurements. The first addressing scheme 160 is a specific implementation of the combined readout configuration 135.

[0308] The first addressing scheme 160 comprises a drive module 161 configured to output drive signals 128, 130 to the photo-capacitive sensor 160. The drive module 161 forms part of the controller 136, and the number of transmitter outputs 1621,..., 1626 of said drive module is less than the number N of first electrodes 138 in the third photo-capacitive sensor 137. For ease of subsequent explanation, the first electrodes are labelled a1 to f5 in Figure 31 the third photo-capacitive sensor 137. Each transmitter output 162 is connected to a set of two or more first electrodes 138a1,..., f5 via a respective multiplexer 164. For example, the first transmitter output 1621 is connected to the first electrodes f1, f2, f3, f4 and f5 by a multiplexer 1641. The multiplexers 1641,..., 1646 can be provided by (or form part of) a transmitter switch network 165 (e.g. provided by or form part of the controller 136).

[0309] The output from each multiplexer 164 is connected to a subset of first electrodes (e.g. a1, a2, a3, a4) that are spatially grouped within the third photo-capacitive sensor 137. In other words, each transmitter output 162 can be multiplexed to first electrodes 138a1,..., f5 that correspond to a particular stripe or strip of the third photo-capacitive sensor 137. The stripes corresponding to different groups of first electrodes 138a1,..., f5 are indicated by horizontal chain lines in Figure 31 .

[0310] The output to which each transmitter output 162 is connected by the transmitter switch network 165 is controlled by a first control signal 166 provided by a processor (not shown) of the controller 136. In general, the controller 136 can contain one or more digital electronic processors (not shown), random access memory (not shown), and nonvolatile memory (not shown), in addition to certain elements such as the drive module 161. The drive module 161, the transmitter switch network 164 and other components of the controller 136 described below can be provided by hardware circuitry, software modules executed by one or more processors of the controller 136, or a combination of hardware and software.

[0311] The spacing of the first electrodes 138a1,..., f5 should be fine enough to allow the resolution of the reflective pattern to be measured. For example, for a fingerprint measurement, the pitch of the first electrodes 138a1,..., f5 can be on the order of 50 pm, and each transmitter channel 162 can be connected through a multiplexer 164 to a region of 80 individual first electrodes 138a1,..., f5 (for visual clarity, Figure 31 only a 5-way split is shown). In comparison, a typical projected capacitive touch sensing panel can use an electrode pitch of several millimetres, e.g. 5 mm.

[0312] To reduce scan time, frequency division multiplexing of the drive signals 128, 130 can be used to simultaneously drive each of the transmitter outputs 1621,..., 1626 to minimize cross-talk between channel groups.

[0313] For projected capacitance sensing, it can be too time consuming and / or unnecessary to scan all of the electrodes in each group (e.g., a1 to a5, or e1 to 35). Instead, a subset of the first electrodes 138a1,..., f5 can be driven for projected capacitance mode. For example, only one first electrode 138 per transmitter channel 162 can be used, such as a3, b3, c3, d3, e3, and f3.

[0314] Alternatively, during projected capacitance sensing, two or more (or all) of the first electrodes 138 of each group can be connected together (using the switch network 166) for common driving. For example, the first electrodes b1, b2, b3, b4, and b5 can be connected together and driven as a single electrode in the projected capacitance sensing mode.

[0315] In response to a projected capacitance sensing mode that detects a user touch, the transmitter switch network 165 can be used to address and drive all of the first electrodes 138a1,..., f5 corresponding to the measurement region 149 for high resolution photo-capacitance measurements. For example, a user's finger can be detected at low resolution, followed by a high resolution scan of the measurement region 149 to extract the user's fingerprint. This can be compared to stored data to decide whether to allow the user to unlock the phone, or open a high security application (or "app") such as a bank application.

[0316] Additionally, in some examples, a larger portion of the first electrodes 138a1,..., f5 can be used to locally second project capacitance scan the roughly detected touch location to obtain an accurate estimate of the size and / or shape of the interaction region 147 prior to the photo-capacitance scan.

[0317] The second electrodes 139 are similarly sized to the first electrodes 138, e.g., have the same pitch. For the purposes of the following discussion, the second electrodes 139 of the third photo-capacitance sensor 137 are labeled g1 to k5 in Figure 31 .

[0318] On the receive side, the multiple groups of second electrodes 139g1,..., k5 are connected to respective amplifiers 172 by respective multiplexers 168. For example, the second electrodes g1, g2, g3, g4, and g5 are connected to the first amplifier 1721 by the multiplexer 1681. The configuration is similar to the transmitter side, and each group of second electrodes 139 (e.g., h1 to h5, j1 to j5, etc.) corresponds to a strip or stripe of the third photo-capacitance sensor 137, asFigure 31 The vertical dashed lines in FIG. 14 indicate.

[0319] The multiplexers 1681,..., 1685 are provided by or formed as part of a receiver switch network 167. The receiver switch network 167 is part of the controller 136 in the same way as the drive module 161 and / or the transmitter switch network 165. The connection paths through the receiver switch network 167 are controlled by second control signals 169 provided by a processor (not shown) of the controller 136.

[0320] In a similar way as the addressing of the first electrodes 138a1,...,f5, for the projected capacitive sensing mode, it is not necessary to scan or monitor each of the second electrodes 139g1,...,k5. Instead, each multiplexer 168 can monitor a single second electrode 139, for example the second electrodes 139g3,h4,i3,j3 and k3 can be monitored for touch sensing by projected capacitance. Likewise, two of the more second electrodes 139g1,...,k5 can be connected together and monitored as a single electrode.

[0321] The output of each amplifier 1711,...,1715 is converted to the digital domain by a respective bandpass filter 1741,...,1745 and by an analog-to-digital converter (ADC) 1751,...,1755. Each set of amplifier 171, filter 174 and ADC constitutes a receiver channel of a front-end module 171. The front-end module 171 is provided by or formed as part of the controller 136 in the same way as the drive module 161, the transmitter switch network 165 and the receiver switch network 167. The receiver outputs 1701,...,1705 are passed to a processor (not shown) of the controller 136 for determining the touch position in the projected capacitive mode and the reflection pattern of the object 39 in the photo-capacitive mode.

[0322] In this way, conventional touch sensing using an existing projected capacitive touch controller can be combined with photo-capacitive measurements using the same touch controller with minimal modifications to the control electronics. In addition, minimal modifications to the touch sensor stack-up or structure are required since the layer 140 of photo-capacitive material 2 can replace any existing dielectric layer of a capacitive touch sensor / touch screen.

[0323] While for biometric recognition of fingerprints it is advantageous to scan only the measurement area 149 determined based on the projected capacitive measurements, there are some applications where it can be useful to scan each photo-capacitor 141 in the array 36. For example, a mobile phone or tablet computer configured with the combined readout configuration 135 and the first addressing scheme 160 can be used to scan a document into a file.

[0324] Similarly, a user can use their device equipped and configured as described herein to scan textures, materials, fabrics, etc. Information obtained using the optoelectronic capacitive scan can be sent to an online store to help the user identify matching textures, materials, fabrics, etc. that they can wish to purchase.

[0325] While Figure 31 While the first and second electrodes 138, 139 are shown subdivided into fine pitches that span the entire area of the third optoelectronic capacitive sensor 137, in other examples a hybrid addressing scheme can be used. For example, only some of the transmitter outputs 162 can be multiplexed to the high resolution first electrodes 168 (and similarly for the second electrodes 169 and receiver channels), such that the areas where the high resolution first and second electrodes 168, 169 intersect provide areas available for high resolution optoelectronic capacitive measurements (e.g. to measure fingerprints for biometric identification), while reducing the total number of electrodes and manufacturing complexity.

[0326] While the first addressing scheme 160 has been illustrated using the third optoelectronic capacitive sensor 137, the same or equivalent addressing scheme can be applied to the first or second optoelectronic capacitive sensors 32, 47.

[0327] Referring also to Figure 32 a second addressing scheme 180 is shown.

[0328] The second addressing scheme 180 is the same as the first addressing scheme 160, except for the routing between the transmitter channels 162 and the first electrodes 138a1,...,g5 and the routing between the second electrodes 139g1,...,k5 and the receiver channels 172, 174, 175.

[0329] In particular, the outputs of the multiplexers 1641,...,1646 are staggered, rather than connected to a spatially grouped subset of the first electrodes 138a1,...,f5, such that in a spatially grouped subset of the first electrodes 138a1,...,f5, each first electrode 138a1,...,f5 in the group can be connected to a different transmitter output 162 via a respective multiplexer 164. For example, Figure 32 The outputs of the multiplexers 1642 in are connected to the first electrodes b1, c2, d3, e4 and f5. At the same time, the first electrodes e1, e2, e3, e4 and e5 corresponding to the measurement zone 149 can be driven simultaneously via respective multiplexers 1641, 1642, 1643, 1644, 1645 (using frequency division multiplexed drive signals 130) by respective transmitter outputs 1621, 1622, 1623, 1624 and 1625. The receiver switch network 167 is similarly configured.

[0330] This second addressing scheme 180 is more complex than the first addressing scheme 160, but can allow for faster high-resolution photo-capacitance scanning to measure, for example, a user's fingerprint, because it is able to drive and / or monitor closely spaced electrodes 138, 139 simultaneously.

[0331] Hand / palm detection

[0332] Although a method has been described of using projected capacitance measurements to locate a touch position, followed by a high-resolution photo-capacitance scan to obtain, for example, a fingerprint, the systems and methods of the present specification are not limited to a single touch and / or fingerprint at a time.

[0333] For example, also with reference to Figures 33A to 33C It is possible to detect the whole hand / palm.

[0334] With specific reference to Fig. 33a, a user's hand 182 has (typically) five fingers 1461,..., 1465.

[0335] With specific reference to Figure 33B If the whole hand is pressed onto the input surface 30, the corresponding interaction area 147 will correspond to the outline of the hand.

[0336] In combination with the projected capacitance and photo-capacitance functionality, the device 111, for example using a separate readout configuration 124, a time-division multiplexed readout configuration 132 or a combined readout configuration 135, can be further configured to analyze the shape and / or size of one or more interaction areas 147 to determine suitable measurement areas 149 (and, if appropriate, dark areas 148).

[0337] With specific reference to Figure 33C The device 111 can determine whether a user interaction (i.e. a detected interaction area 147) corresponds to all or part of a user's hand 182 in contact with the input surface 30, and in response to determining that the detected interaction area 147 corresponds to all or part of a user's hand, determine one or more measurement areas 149 in the form of a fingerprint area corresponding to the end of a finger 1461,..., 1465. In Figure 33C In the example shown, the device 111 identifies the end of each finger and thumb, and assigns corresponding measurement areas 1491,..., 1495. Photo-capacitance can then be measured corresponding to each measurement (fingerprint) area 1491,..., 1495.

[0338] Other measurement areas 149 can also be defined, for example, a pattern of skin ridges on a user's palm can be added to the fingerprint data to increase security.

[0339] Different sizes and / or shapes of measurement areas 149 can be defined for photo-capacitance imaging using different colors of light source 31. For example, also with reference to Figure 33DThe measurement zones 1831,..., 1835 can define IR imaging (preferably near-IR, NIR) for sub-surface veins. The measurement zones 1831,..., 1835 for vein imaging can extend further along each finger 1461,..., 1465 than the corresponding measurement zones 1491,..., 1495 for the fingerprint. Vein imaging can help prevent spoofing, as the vein pattern under the user's skin is also unique and more difficult to spoof (using a replica fake, etc.). The scan resolution for vein imaging can be lower than for the fingerprint scan, to reduce scan time and power consumption.

[0340] For authentication purposes, it must be ensured that a sufficiently large area is measured to avoid matching similar areas of larger different patterns.

[0341] Reference is also made to Figure 34A A first contact zone 1841 of the user's finger 146 with the input surface 30 is shown, where the resolution of the projected capacitive scan is visually indicated by the dashed lines forming a grid. Figure 34B The corresponding first interaction zone 1471 is shown.

[0342] Reference is also made to Figure 35A A second contact zone 1842 of the user's finger 146 with the input surface 30 is shown, where Figure 35B The corresponding second interaction zone 1472 is shown.

[0343] Reference is also made to Figure 36A A third contact zone 1843 of the user's finger 146 with the input surface 30 is shown, where Figure 36B The corresponding third interaction zone 1473 is shown.

[0344] The different sizes of the contact zones 184 are related to different pressures with which the user presses the finger 146 against the input surface 30. Generally speaking, the more the finger is pressed 146, the larger the contact zone 184 becomes and the more of the corresponding finger / thumbprint will be in contact or close enough to the input surface 30 for the photo-capacitive scan.

[0345] The device 111 will only measure the interaction zones 1471, 1472, 1473, so the area (and optionally the shape) of the interaction zones 1471, 1472, 1473 needs to be analyzed. The comparison of the photo-capacitive pattern to the set of one or more authorized patterns 119 can be conditioned on the interaction area 147 (and more specifically the corresponding measurement area if different) exceeding a minimum area. For example, it can be determined that the first interaction zone 1471 and the second interaction zone 1472 are large enough (e.g. exceed a threshold) so that a meaningful part of the finger / thumbprint can be obtained, whereas the third interaction zone 1473 can be too small.

[0346] The size of the interaction area 147 can be determined based on the projected capacitance measurement alone or using a combination of the projected capacitance measurement and the photo-capacitance measurement.

[0347] When the device 111 includes a display and determines that the interaction area 147 is insufficient for the comparison, the display can be controlled to display a message informing the user to reposition their finger (or palm, etc.) and / or press harder to allow a more complete measurement.

[0348] Transmission-based opto-capacitance sensing

[0349] Examples have been described that are configured to use the photo-capacitors 32, 47, 141 to detect light from the light source 31 that is reflected from an object 39 that is in contact or in proximity (e.g., <1 mm) to the input surface.

[0350] However, the array 36 of photo-capacitors 32, 47, 141 and the associated readout and addressing schemes described above can be applied to other applications.

[0351] For example, also with reference to Figure 37 a presentation system 190 is shown.

[0352] The presentation system 190 includes a fourth photo-capacitive sensor 191 that includes an input surface 30 and an array 36 of photo-capacitors 32, 47, 141 arranged to receive light 192 from a light source 193 that is transmitted through the input surface 30. The light source 193 is a highly collimated light source, such as a laser pointer, with a low divergence angle 194. The spacing between elements of the array 36 of photo-capacitors 32, 47, 141 should be configured for detecting a laser point spot, for example, between about 1 mm and 5 mm. The presentation system 190 also includes a controller 195 configured to monitor the photo-capacitance of the fourth photo-capacitive sensor 191.

[0353] Here the input surface 30 can correspond to a large size display screen, a transmissive instrument directed smart screen, and similar systems for displaying content to an audience on a large scale. The addition of the fourth photo-capacitive sensor 191 can allow a presenter to use a laser pointer to provide a cursor with functionality similar to a mouse or trackball to interact with the displayed content.

[0354] While the application has been presented in the general context of what is presently considered to be the most practical implementation, it should be appreciated that any or all aspects of the application can be embodied in other applications and contexts. Therefore, specific claims are not to be interpreted as applying only to only those combinations considered in the specific examples, which are included for illustrative purposes only and are not to be interpreted as limiting. It is therefore evident that particular features of the application can be interchanged with other features described, that the scope of the application should not be determined with reference to this description alone, and that the application can include any other combinations described or equivalents thereof without departing from the spirit and scope of the application. Accordingly, the application includes all modifications and equivalents of the features described herein, and any further applications and uses of the application. It is intended, therefore, to be limited only by the scope of the appended claims.

Claims

1. An apparatus comprising: A photoelectric capacitive sensor, wherein the capacitive sensor includes: Input surface; One or more light sources are arranged to illuminate a portion of the input surface; A photocapacitor array is arranged to receive light from one or more light sources, the light being reflected from an object that is in contact with or close to the irradiated portion of the input surface; The photocapacitor array is configured to detect the reflection pattern of the object; A controller, connected to the photocapacitive sensor and configured to measure the capacitance of the photocapacitive array, includes: Measure the capacitance of at least one subset of the photocapacitor array; The interaction region is determined based on the capacitance of the subset of the photocapacitor array; Deactivate each light source corresponding to the interaction area; Measure the projection capacitance component corresponding to each photocapacitor in the interaction region; Activate at least one subset of the light sources corresponding to the interaction area; Measure the total capacitance of each photocapacitor corresponding to the interaction region; The photoelectric capacitance component corresponding to the interaction region is determined based on the difference between the total capacitance and the corresponding projected capacitance component.

2. The device of claim 1, wherein the photocapacitor array is configured for detecting fingerprints.

3. The device of claim 1, wherein the one or more light sources are directional and emit light toward the input surface, and wherein the one or more light sources are disposed between the photocapacitor array and the input surface.

4. The device according to claim 1, wherein the photocapacitor array is disposed between the one or more light sources and the input surface, and the photocapacitive sensor further comprises: A light attenuation layer is disposed between the one or more light sources and the photocapacitor array, and is configured to shield the photocapacitor from direct irradiation by the one or more light sources within the wavelength range to which the photocapacitor is sensitive.

5. The device of claim 1, wherein the one or more light sources comprise one or more infrared emitters.

6. The device of claim 1, wherein the one or more light sources comprise one or more emitters selected from red, green and blue emitters.

7. The device according to claim 1, wherein the photocapacitor array comprises: A plurality of first electrodes extending in a first direction and spaced apart in a second different direction; A plurality of second electrodes extending in a second direction and spaced apart in the first direction; A photocapacitive material layer is disposed between the first electrode and the second electrode, such that each intersection of the first electrode and the second electrode provides a photocapacitor for the array.

8. The device according to claim 1, wherein the photocapacitor array comprises: A plurality of first electrodes extending in a first direction and spaced apart in a second different direction; A plurality of second electrodes extending in a second direction and spaced apart in the first direction; The plurality of first electrodes and the plurality of second electrodes are substantially coplanar and disposed on or above the photocapacitor material layer, such that each intersection of the first electrodes and the second electrodes provides a photocapacitor for the array.

9. The apparatus of any one of claims 1 to 8, wherein, The photocapacitive sensor is included in a display screen having a cover plate and a display stack, wherein the display stack includes the photocapacitive sensor, and wherein the cover plate provides the input surface.

10. The device of claim 9, wherein the display stack includes a backlight layer; The backlight layer provides the one or more light sources, or the backlight layer includes the one or more light sources.

11. The device of claim 9, wherein the display stack comprises a pixel layer in the form of a light-emitting diode array; The light-emitting diode array provides the one or more light sources, or the light-emitting diode array includes the one or more light sources.

12. The device of claim 9, wherein the display stack comprises a thin-film transistor layer; The thin-film transistor layer provides the photocapacitor array, or the thin-film transistor layer includes the photocapacitor array.

13. The device of claim 9, wherein the display stack comprises a thin-film transistor layer and a separate photocapacitor layer.

14. The device of claim 9, wherein the display stack has a display area, and wherein the portion of the input surface corresponds to a first area of ​​the display area.

15. The device of claim 14, further comprising a second photocapacitive sensor identical to the photocapacitive sensor, wherein the second photocapacitive sensor is associated with a portion of the input surface, the portion corresponding to a second area of ​​the display area that is different from the first area.

16. The device of claim 9, wherein the display stack has a display area, and wherein the portion of the input surface substantially corresponds to the display area.

17. The device of claim 9, wherein the display stack includes conductive traces for projecting capacitive touch sensing.

18. The apparatus of claim 1, wherein, The device also includes an access control device, which includes the photocapacitive sensor.

19. The apparatus of claim 9, wherein, The device also includes an access control device, which includes the display screen.

20. The device of claim 1, configured to detect user interaction in response to using projected capacitance measurement: Determine whether the user interaction corresponds to all or part of the user's hand in contact with the input surface; In response to determining that the user interaction corresponds to all or part of the user's hand, one or more fingerprint areas are determined; In response to determining one or more fingerprint regions, the photocapacitance corresponding to each fingerprint region is measured.

21. The device of claim 1, wherein when one or more light sources are irradiated without any object above or in contact with the input surface, the controller stores a reference frame corresponding to the measured capacitance of the photocapacitor array; The controller is further configured to subtract the reference frame from the capacitance measured from the photocapacitor array.

22. The device according to claim 1, wherein: The controller is further configured to control light emission from the one or more light sources; or The second controller is configured to control the light emission from the one or more light sources.

23. The device of claim 1, further configured such that, in response to detecting a touch using a projected capacitance, the controller measures the capacitance of the photocapacitor array.

24. The device of claim 1, further configured such that in response to detecting a touch using projected capacitance: The controller illuminates the one or more light sources; The controller measures the capacitance of the photocapacitor array.

25. The device of claim 22, further configured to respond to detection of a touch using projected capacitance: The second controller illuminates the one or more light sources; The controller measures the capacitance of the photocapacitor array.

26. The device of claim 1, wherein the one or more light sources comprise one or more infrared light sources and one or more red light sources, wherein the controller is configured to: Irradiate the infrared light source and measure the first set of capacitances from the photocapacitor array; Illuminate the red light source and measure the second set of capacitances from the photocapacitor array; Furthermore, the controller is configured to compare the first set of capacitors and the second set of capacitors to determine whether an object above or in contact with the input surface corresponds to human skin.

27. The device of claim 26, wherein the controller is further configured to control the one or more infrared light sources and the photocapacitive sensor to detect and / or image one or more veins included in the object.

28. The device of claim 22, wherein the one or more light sources comprise one or more infrared light sources and one or more red light sources, wherein the second controller is configured to: Irradiate the infrared light source and measure the first set of capacitances from the photocapacitor array; Illuminate the red light source and measure the second set of capacitances from the photocapacitor array; Furthermore, the controller is configured to compare the first set of capacitors and the second set of capacitors to determine whether an object above or in contact with the input surface corresponds to human skin.

29. The device according to claim 1, wherein the device is configured to: The capacitance pattern measured using the array is compared with a set of one or more authorized patterns; A signal is output in response to the capacitance pattern measured using the array matching the authorized pattern in one or more authorized patterns.

30. The device of claim 29, wherein the comparison of the capacitance pattern with the set of one or more authorized patterns is conditioned on the measured capacitance pattern corresponding to the interaction region exceeding the minimum region.

31. A method of using the apparatus of any one of claims 1 to 29, the method for measuring capacitance of the array of optoelectronic capacitors 。 32. The method of claim 31, further comprising: When the one or more light sources are illuminated without any object above or in contact with the input surface, a reference frame corresponding to the measured capacitance of the photocapacitor array is retrieved or obtained; Subtract the reference frame from the capacitance measured using the photocapacitor array.

33. The method of claim 31, further comprising: The capacitance pattern measured using the array is compared with a set of one or more authorized patterns; A signal is output in response to the capacitance pattern measured using the array matching the authorized pattern in one or more authorized patterns.

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