Optical sensor with mutually abutting basic sensors - Patent 7323633

Abstract

To provide a photosensitive sensor with elementary sensors abutting each other.SOLUTION: A photosensitive sensor includes multiple elementary sensors 32 abutting each other, each elementary sensor comprising pixels organized in rows, the pixels of each row being connected to multiple types of conductors Col, Vdd, VRst, Rst, column conductors Col of which are connected to read circuits L of the sensor. The photosensitive sensor moreover comprises, connected to each of the column conductors Col, a group 40 of components that is separate from the conductor under consideration, the group 40 of components forming an impedance for matching the conductor Col under consideration. The impedances in each elementary sensor 32 have the same value and the impedances for different elementary sensors have different impedance values so as to balance the link impedances between the various read circuits L and the corresponding column conductors Col for the various elementary sensors.SELECTED DRAWING: Figure 4

Description

[Technical field]

[0001] The invention relates to a photosensitive device comprising a matrix of optical pixels, in particular of the type produced by semiconductor material deposition techniques, which can be implemented for X-ray imaging to detect ionizing radiation and in particular for radiological imaging in the medical field or for non-destructive testing in the industrial or safety fields. [Background technology]

[0002] Electronic light sensors are manufactured in the form of flat panels. They contain a matrix of, so to speak, component blocks of basic electronic circuits. The basic electronic circuits are arranged in rows, or more precisely in rows and columns, forming a matrix. The basic electronic circuits are also called pixels in image sensors. A pixel is formed, for example, from a photosensitive zone that provides a flow of charge based on the flow of photons it receives, and from an electronic circuit for processing this current. The photosensitive zone comprises, for example, a photodetector, such as a photodiode, a photoresistor or a phototransistor. In addition to the photosensitive element, the pixel also comprises an electronic circuit within the pixel, whose function is that of current collection, of control or of processing. This circuit is often manufactured from semiconductor components, for example diodes or transistors, and can provide functions such as opening and closing the circuit, resetting the photodetector, amplification, etc.

[0003] The photosensor further comprises conductors connecting the pixels. These conductors may extend in rows, connecting the pixels row by row, or in columns, connecting the pixels column by column. The row and / or column conductors provide the necessary polarization, control, and output channels for the information sensed by each pixel. In practice, the terms row or column are purely arbitrary. The terms may of course be interchanged.

[0004] Optical sensors are often manufactured by thin-film deposition techniques of semiconductor materials on glass or silicon-based substrates. In imaging implementing ionizing radiation and especially X-rays, the difficulty of focusing this type of radiation has led to the manufacture of large optical sensors. The dimensions of the sensors are often larger than the conventional dimensions of the substrate. For example, substrates with a diameter of 200 or 300 mm are commonly found. In contrast, optical sensors are generally rectangular and their maximum dimension exceeds 400 mm. To manufacture these sensors with large dimensions, it is a known practice to abut several substrates against each other. A method for manufacturing such sensors abutting each other, in which a scintillator is able to convert the wavelength of the X-photons received by the sensor into a wavelength to which the photodetector is sensitive, is described for example in WO 2008 / 142135 A1 filed in the name of the present applicant. In that patent, the physical alignment of the various elementary sensors is described, each manufactured on its own substrate. The patent does not concern possible electrical differences between the various elementary sensors. In another patent application, WO 02 / 41621 A2, the applicant expresses an interest in adjusting the polarization of the pixels of the various elementary sensors differently. This adjustment makes it possible to limit the difference in output levels of adjacent pixels when said pixels are saturated, since the output levels of the various pixels can differ from one elementary sensor to another. WO 02 / 41621 A2 also describes the application of offset and gain corrections to adapt the response curves of the various pixels, especially when they are included in different elementary sensors. These various adjustments are effective at the level of the respective output of the pixels and when the reading of the pixel matrix is ​​slow. However, the length of the row conductors can interrupt the driving and reading of the pixel matrix. This becomes more severe at higher speeds at which the matrix is ​​driven and read. In-house tests have shown that the impedance of the conductors can differ significantly, especially when they are included in different elementary sensors that abut against each other. It is possible to specify tight tolerances in the impedance of the conductors.These tight tolerances tend to increase the overall manufacturing costs of the sensor. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] International Publication No. 2008 / 142135 [Patent Document 2] International Publication No. 2002 / 41621 Summary of the Invention [Problem to be solved by the invention]

[0006] The present invention aims to eliminate tolerances on the value of the impedance of the conductor itself by adding specific components placed in parallel or series with each conductor to balance the overall impedance of adjacent conductors as seen from outside the matrix. [Means for solving the problem]

[0007] To this end, the subject of the invention is an optical sensor comprising a number of mutually abutting elementary sensors, each of which comprises a pixel matrix arranged in rows, the pixels of each row being connected to a number of types of conductors, the column conductors of which are connected to a readout circuit of the sensor. The optical sensor further comprises, connected to each of the column conductors, a set of components separate from the conductor under consideration, which form an impedance for matching with the conductor under consideration. The impedances within each elementary sensor have the same value, and the impedances of the different elementary sensors have different impedances, so as to balance the link impedance between the various readout circuits for the various elementary sensors and the corresponding column conductors.

[0008] Furthermore, the pixels of each row are connected to conductors of the power conductor type, which are connected to a circuit for powering the sensor. Advantageously, the optical sensor comprises components connected to each of the power conductors, separate from the conductor under consideration, which components form an impedance for matching with the conductor under consideration. The impedance in each elementary sensor has the same value, and the impedance in the different elementary sensors has different impedance values, to balance the link impedance between the various power supply circuits for the various elementary sensors and the corresponding power supply conductors.

[0009] Furthermore, the pixels of each row are connected to conductors of the control conductor type, which are connected to a circuit that controls the sensor. Advantageously, the optical sensor includes components connected to each of the control conductors, separate from the conductor under consideration, which components form an impedance for matching with the conductor under consideration. The impedances in each elementary sensor have the same value, and the impedances in the different elementary sensors have different impedance values ​​to balance the link impedances between the various control circuits for the various elementary sensors and the corresponding control conductors.

[0010] For two separate elementary sensors, at least one type of conductor may have a different length, in which case the impedance values ​​of the components associated with at least one type of conductor are matched based on their respective lengths.

[0011] The group of components advantageously includes a resistor connected in series on the conductor under consideration and a capacitance connected between the conductor under consideration and the earth of the device.

[0012] Each group of components is advantageously arranged on the substrate of the corresponding elementary sensor, between the pixel matrix and the circuitry to which the relevant conductors are connected.

[0013] The elementary sensors are advantageously each formed on a separate substrate.

[0014] The invention will be better understood and further advantages will become apparent on reading the detailed description of one embodiment thereof, given by way of example, and illustrated by the accompanying drawings, in which: [Brief description of the drawings]

[0015] [Figure 1] 2 shows a schematic representation of an exemplary pixel matrix 1T that may be implemented in a sensor according to the invention. [Diagram 2] 2 shows a schematic representation of an exemplary pixel matrix 3T that may be implemented in a sensor according to the invention. [Diagram 3] 1 shows a schematic representation of an exemplary sensor made from a number of elementary sensors abutting each other. [Figure 4] 1 shows a portion of one of the basic sensors in more detail. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0016] For purposes of clarity, the same elements are provided with the same reference numbers in different drawings.

[0017] The following description is provided in terms of a matrix array detector formed from a number of elementary electronic circuits, called pixels, each of which comprises an element sensitive to a physical quantity, which in the example described are pixels sensitive to optical radiation. It will be appreciated that the invention may also be implemented with other detectors sensitive to any form of physical quantity, for example capable of producing pressure or temperature maps.

[0018] Fig. 1 shows, for ease of understanding, a schematic matrix 10 with 2 rows by 2 columns. Four pixels P are formed, each at the intersection of one row and one column. Of course, a real matrix array is generally much larger than this and features a large number of rows and columns. The matrix 10 belongs to a matrix array detector and allows a digitized image to be generated.

[0019] Each pixel P comprises a photosensitive zone, represented here by a photodiode D, and an electronic processing circuit, formed in the example of Fig. 1 by one transistor T. The references of the components D and T are followed by two coordinates (i,j), where i can be the rank of the row and j the rank of the column. This pixel is also called a 1T pixel, since it has one transistor whose function will be described later.

[0020] Generally, it is known practice to manufacture pixel matrices including transistors implemented with complementary crystalline silicon semiconductors, known under the abbreviation CMOS, which stands for "complementary metal oxide semiconductor". The invention is not limited to this type of transistor, but may also be implemented, for example, with matrices including thin film field effect transistors, known under the name TFT, which stands for "thin-film transistor". TFTs are transistors based on metal oxide films, for example amorphous or crystalline indium, gallium and zinc oxide, known under the abbreviation IGZO. Other families of TFT type transistors may also be implemented, for example organic TFTs, amorphous silicon TFTs or polycrystalline silicon TFTs.

[0021] The pixels P of one and the same column are connected to column conductors Col, which allow the collection of information from the pixels connected thereto, and the pixels P of one and the same row are connected to row conductors Sel, which carry signals, making each of the rows of pixels controllable.

[0022] During the image capture phase, the illumination received by each of the photodiodes D reduces the potential of its cathode on which charge accumulates in response to the illumination received. This image capture phase is followed by a readout phase during which the potentials of the photodiodes D are read. For this purpose, the transistor T is switched on by a row selection control carried by the conductor Sel and applied to the gate of said transistor, thus acting as a switch. The various rows of pixels are read out sequentially. The column conductors Col are used sequentially to collect information from the pixels in the various columns as they are selected. The readout phase drains the charge of the photodiode D and allows it to be reset before a new image capture phase.

[0023] The invention can also be implemented in detectors in which the pixels are simpler, in particular by replacing the transistor T with a simple diode that is switched on by a row select signal.

[0024] 2 shows diagrammatically another example of a pixel matrix 20, designated Q, which can also be incorporated in an image detector according to the invention. Inside each pixel Q is a photodiode D and an electronic processing circuit, in this example formed by three transistors T1, T2 and T3. As before, the references of the photodiode D and the three transistors are followed by two coordinates (i,j), where i is the rank of the row and j is the rank of the column. In practice, this type of pixel can include other components, in particular other transistors. This pixel is therefore called a 3T pixel, since it has at least three transistors.

[0025] The pixels Q in one and the same column share a transistor T5 at the end of the column conductor Col. The pixels Q in one and the same row are connected to four row conductors, Sel(i), Vdd, VRst, and Rst(i), which allow control of each of the rows of pixels.

[0026] The transistor T1 makes it possible to reset the voltage of the cathode of the photodiode D to the voltage carried by the conductor VRst. Initially, this voltage remains constant and does not change during the image capture and readout phase. During the reset operation, the voltage VRst is applied to the cathode of the diode D while the control signal carried by the conductor Rst is active.

[0027] In the image capture phase, which begins after the reset operation, the illumination received by the photodiode D of pixel Q causes, for pixel P, a drop in the potential of its cathode. This image capture phase is followed by a readout phase, in which the potential of the photodiode D is read. To do this, the transistor T3 is switched on by a pixel selection control applied to its gate and carried by the conductor Sel, thus acting as a switch. The transistor T3 of the 3T pixel has the same functional role as the transistor T of the 1T pixel described with reference to FIG.

[0028] The transistor T2 acts as a follower and is powered by the voltage carried by the conductor Vdd. The transistor T5 acts as a current source. The transistors T2 and T5 then form a voltage follower stage, which copies the voltage present on the cathode of the photodiode D and reproduces it to within a certain offset on the column conductor Col when the transistor T3 is turned on. To generate the copy, the transistor T2 needs a polarization current flowing through its drain and its source. This current is provided by a current generator formed by the transistor T5, which may or may not be common to several pixels. In the example shown, the transistor T5 is common to the column of pixels. It is also possible to use only one transistor T5 as a current source for the entire matrix, provided that it is successively switched to the various columns when these columns themselves are read. The column conductor Col is used both to polarize the transistor T2 and to collect information from the pixels in the corresponding column when said pixels are selected by the signal Sel. Alternatively, the column conductor Col can be separated in order to separate its two functions.

[0029] The invention can also be implemented for pixels whose operation is different. By way of example, the invention can be implemented for a 4T pixel. In addition to transistors T1, T2 and T3, the 4T pixel includes an additional transistor arranged between the cathode of the photodiode D and the gate of the transistor T2, which forms the node of the pixel. This additional transistor allows the transfer of the charge stored in the photodiode D to the node of the pixel at a selected moment in time.

[0030] A column conductor in the example of FIG. 1 and several column conductors in the example of FIG. 2 are connected to various pixels P or Q in one and the same column. A control circuit, generally a shift register, not shown in FIGS. 1 and 2, when implemented, generates the control signals carried by the conductors Sel(i) and Rst(i) and connected to the corresponding row conductors. In the variant of FIG. 2, a power supply circuit, also not shown, generates the voltages carried by the conductors Vdd and VRst, but connected to the corresponding row conductors. The voltages of the signals carried by the conductors Vdd and VRst are constant and may be the same, for which purpose one type of row conductor can be used to carry the two signals, the power supply to this type of conductor being provided by one and the same power supply circuit. This type of common conductor is then connected to the transistors T1 and T2 of each of the pixels Q. The conductors Vdd and VRst are also called power supply conductors, since the voltages applied thereto are constant. The control circuit and, if necessary, the power supply circuit are arranged at the end of the row. Furthermore, a readout circuit is arranged at each end of the column conductors Col.

[0031] The terms row and column are purely arbitrary and can be interchanged. In fact, the control and power circuits can be arranged on one side of the matrix and the readout circuits on a side of the matrix perpendicular to the side on which the control and power circuits are arranged. To simplify the connection of the various circuits, it is also possible to arrange all the circuits, i.e. the control, power and readout circuits, on the same side of the matrix.

[0032] A readout circuit associated with the column conductor Col can, for example, digitize the signals collected on the column conductor. The various readout circuits can include a multiplexer, which allows the signals emanating from an entire column of pixels to be collected. Once a row has been read out by the readout circuit, a new column can be selected for repeating the readout operation.

[0033] FIG. 3 shows a schematic example of a sensor 30 including four elementary sensors 32, 34, 36 and 38, each formed on an independent substrate, respectively 32b, 34b, 36b and 38b. The elementary sensors and therefore the respective substrates have the same shape. In the illustrated example, the elementary sensors 32, 34, 36 and 38 are rectangular and abut each other along one side. A rectangular shape is suitable for a pixel matrix whose rows and columns run perpendicularly with respect to each other. The invention can also be implemented with other polygonal shapes of the elementary sensors. The invention can be implemented regardless of the number of elementary sensors. Each of the elementary sensors 32, 34, 36 and 38 includes a pixel matrix as described in FIG. 1 or FIG. 2. These four elementary sensors 32, 34, 36 and 38 abut each other to form the sensor 30. Each sensor includes a zone, respectively 32a, 34a, 36a and 38a, in which the readout circuit and the transistor T5 are arranged. Zones 32a, 34a, 36a and 38a do not include any pixel. Zones 32a, 34a, 36a and 38a are located at the level of the free ends of the columns, i.e. the ends that are not in contact with other elementary sensors. Where the elementary sensors abut each other, the pixels are brought as close as possible. In order to prevent any image splitting where the elementary sensors abut each other, the pixels of the different elementary sensors are spaced apart with the same step that separates two adjacent pixels of one and the same elementary sensor. The conductors of the various elementary sensors are not connected to each other where the elementary sensors abut each other. In other words, where the elementary sensors abut each other, there are no conductors connecting one elementary sensor to the other. In each of the elementary sensors 32, 34, 36 and 38, the row conductors pass between the pixels of the various rows in the matrix. More precisely, the conductors Sel, Vdd, VRst and Rst run between the rows of pixels in their respective elementary sensors, and the conductors Col run between the columns of pixels in their respective elementary sensors. Each of the elementary sensors 32, 34, 36 and 38 includes a control circuit by means of which it is able to generate the signals carried by its own conductors Sel and Rst.Each of the elementary sensors 32, 34, 36 and 38 also includes a power supply circuit, by which it is possible to generate the signals carried by its own conductors Vdd and VRst. The control circuit and the power supply circuit can be arranged at the free end of the row. Alternatively, they can be arranged in the zones 32a, 34a, 36a and 38a. The conductors Sel, Vdd, VRst and Rst are then arranged in columns, as are the conductors Col. The same applies to the column conductors, by which the pixels can be read. Each elementary sensor includes its own readout circuit. The column conductors Col of the various elementary sensors are not connected to each other, even though they follow one another. Later, the direction of the conductors is not distinguished, and the invention can be implemented whatever this orientation may be. On the other hand, the various types of conductors are distinguished.

[0034] Figure 4 shows in more detail one of the elementary sensors, more specifically the elementary sensor 32 and its zone 32a. This detail applies to all of the elementary sensors. In the part of the diagram there are two pixels Q1 and Q2 connected to the same column conductor Col. The diagram shown in Figure 4 can easily be converted to a sensor implementing a 1T pixel P as well. In the zone 32a there is a current source, represented by a transistor T5 and a readout circuit L, which includes for example an analog-to-digital converter ADC, by means of which the voltage present on the conductor Col can be digitized during the various readout operations on the various rows of the pixel matrix Q.

[0035] 4 shows a group of components 40 connected to a column conductor Col, which are isolated from the conductor Col and form an impedance for matching with the conductor Col. For each of its column conductors Col, the sensor 30 includes a group of components that form an impedance for matching with the conductor under consideration.

[0036] Within one and the same elementary sensor 32, 34, 36 or 38, the impedances connected to the various column conductors Col have the same value. Between one elementary sensor and the next, the impedances have different values ​​to balance the link impedances between the various readout circuits for the various elementary sensors and the corresponding column conductors Col.

[0037] In Fig. 4, the component group 40 includes a resistor 42 and a capacitor 44. The resistor 42 is connected in series between the read circuit L and the pixel Q2 closest to the read circuit L. The capacitor 44 is connected between one of the terminals of the resistor 42 and the ground 46 of the sensor 30. This RC circuit is provided as an example. The component group may include only resistors without a capacitor. In other words, the component group 40 may include only one component. It is also possible to add an inductor to the group 40, depending on the need for impedance matching.

[0038] The choice of the types of components and their sizes makes it possible to compensate for the effects of differences in the lengths of the conductors of the various elementary sensors 32, 34, 36 and 38. The resistor 42 makes it possible to compensate for differences in the resistance of the conductors. The capacitor 44, together with an inductor possibly associated therewith, makes it possible to compensate for differences that may occur in the settling time of the signal between the moment when the transistor T3 of the pixel is switched on and the moment when the reading circuit L receives this signal during the reading phase.

[0039] The components of the group 40 can be manufactured directly on the substrate of the elementary sensor to which they are associated in the first part 48 of the zone 32a. The same applies to the readout circuit L, which can also be manufactured in the second part 50 of the zone 32a. Downstream of the readout circuit L, the elementary sensor can include a third part 52 of the zone 32a, by means of which the sensor 30 can be connected around its periphery. Around the part 52, the sensor 30 can include a sealing joint 54, which ensures that all the components present on the substrate are leak-free after they abut against each other. The sealing joint 54 is manufactured between an entry window, not shown, and the various substrates of the elementary sensor 32-38. The photosensitive elements can be directly sensitive to the radiation to which the sensor 30 is sensitive. In the field of X-rays, it is common to place a scintillator between the entry window and the elementary sensor 32-38. The scintillator receives the X-ray photons and transmits again photons with lower energy in the wavelength band to which the photosensitive elements are sensitive. The scintillator covers the zone in which the pixels are present. Portions 48 and 50 can be used as scintillator positioning tolerance zones.

[0040] Independently of the components 40 associated with the column conductor Col, the sensor 30 may include other components, 56 and 58, respectively, which are associated with the power supply conductor Vdd and / or the power supply conductor VRst. As with the components 40, the components 56 and 58 are isolated from the conductors, Vdd or VRst, with which they are associated, to form impedances to match the respective power supply conductors. In the example shown in FIG. 4, the components 56 include resistors 60 and capacitors 62. The components 58 include resistors 64 and capacitors 66. The components 56 and 58 are connected to the conductors Vdd and VRst, respectively, in the same manner as the components 40 are connected to the column conductor Col.

[0041] With respect to the power supply conductor VRst, when a pixel is reset by the control carried by the control conductor Rst, the photodiodes D of the various pixels are discharged through the conductor VRst, thus resulting in a voltage drop on this conductor. The difference in length of these conductors depending on the elementary sensor on which they rest results in different voltage drops. As a result, the discharge of the various photodiodes D is not the same, resulting in offset differences between the various pixels. It is possible to correct these differences by adapting the values ​​of the various resistors 64 depending on the elementary sensor on which the relevant conductor VRst rests. Furthermore, resetting a pixel generates an inrush current on the conductor VRst, thereby resulting in an instantaneous voltage drop of a duration that varies depending on the length of the conductor VRst. After this inrush current, the conductor returns to an equilibrium state. The duration of this return to equilibrium also depends on the length of the conductor VRst. It is possible to balance these durations by adapting the values ​​of the capacitors 66 and possibly of the associated inductors.

[0042] As regards the power supply conductor Vdd, which supplies the transistors T2 of the various pixels, in order to copy as faithfully as possible the voltage present on the cathode of the photodiode D, it is necessary to balance the voltage present on this conductor as well as possible on the basis of the various elementary sensors. Voltage differences on the conductor Vdd may have the most noticeable effect in the vicinity of where the various elementary sensors abut each other, which may lead to visible differences in the images related to adjacent pixels belonging to different elementary sensors. Balancing the voltages of the various conductors Vdd in order to limit threshold effects at the places where the elementary sensors abut each other is achieved by resistors 60 for the average values ​​of the voltages, or by capacitors 62 and possibly associated inductors for the settling times of these voltages.

[0043] It is also possible to foresee the balancing of the impedances of the control conductors Sel and Rst. As mentioned before, the balancing of these impedances is achieved by components connected to the corresponding conductors and placed between the pixel matrix and the associated control circuitry. In order to avoid overloading Fig. 4, these components are not shown. They could also be placed in each part 48 of the elementary sensor.

[0044] The various components of groups 40, 56 and 50 can be manufactured by deposition of metal layers on the substrate of the elementary sensor in question. Other manufacturing methods can also be used to obtain in particular resistors, such as the use of zones with a doping opposite to that of the substrate. This method is described in the English literature in <http: / / www.electronics.com / articles / 2010023133 / 110024 ...<well resistor> This leads to the production of a resistor known as a capacitor. A capacitor can be fabricated as a transistor with its drain and source shorted together. [Explanation of symbols]

[0045] 30 Sensors 32, 34, 36, 38 Basic Sensors Zones 32a, 34a, 36a, 38a 32b, 34b, 36b, 38b board 40, 56, 58 Component Groups 42, 60, 64 resistor 44, 62, 66 Capacitors 46 Equipment 54 Sealing joint Col, Sel, Vdd, VRst, Rst conductors L reading circuit P, Q pixels T1, T2, T3, T5 transistors

Claims

1. 1. An optical sensor comprising a plurality of mutually abutting elementary sensors (32, 34, 36, 38), each elementary sensor comprising a pixel matrix (P; Q) arranged in rows, the pixels of each row being connected to a plurality of types of conductors (Col, Sel, Vdd, VRst, Rst), the column conductors (Col) of which are connected to a readout circuit (L) of the sensor, characterized in that the optical sensor comprises a group of components (40) connected to each of the column conductors (Col), separate from the conductors, the group of components (40) forming an impedance for matching with the conductors (Col), the impedances in each elementary sensor (32, 34, 36, 38) having the same value, and the impedances for different elementary sensors having different impedance values, to balance the link impedances between the various readout circuits (L) for the various elementary sensors and the corresponding column conductors (Col).

2. 2. The optical sensor according to claim 1, characterized in that the pixels (P; Q) of each row are connected to a conductor of power supply conductor type (VRst, Vdd) connected to a circuit supplying the sensor, and that each of the conductors of power supply conductor type has a group of components (56, 58) separate from the conductor, which are connected to the conductor and form an impedance to match the conductor, and that the impedance in each elementary sensor has the same value, and that the impedances for different elementary sensors have different impedance values ​​to balance the link impedance between the various power supply circuits for the various elementary sensors and the corresponding power supply conductors.

3. 3. The optical sensor according to claim 1, characterized in that the pixels (P; Q) of each row are connected to conductors of the control conductor type (Sel, Rst) which are connected to a circuit for controlling the sensor, and that it comprises a group of components separate from the conductors (Sel, Rst) connected to each of the conductors of the control conductor type, said group of components forming an impedance for matching with the conductor, and that the impedance in each elementary sensor (32, 34, 36, 38) has the same value, and that the impedance in different elementary sensors has different impedance values ​​to balance the link impedance between the various control circuits for the various elementary sensors and the corresponding control conductors.

4. The optical sensor according to any one of claims 1 to 3, characterized in that for two separate elementary sensors (32, 34, 36, 38), the conductors (Col, Sel, Vdd, VRst, Rst) of at least one type have different lengths and the impedance values ​​of the component groups (40, 56, 58) associated with the at least one type of conductor are matched based on their respective lengths.

5. The optical sensor according to any one of claims 1 to 4, characterized in that the group of components (40, 56, 58) includes resistors (42, 60, 64) connected in series on the conductors (Col, Sel, Vdd, VRst, Rst) and a capacitance (44, 62, 66) connected between the conductors and the ground of the device (46).

6. 6. The optical sensor according to claim 1, wherein each component group (40, 56, 58) is arranged on the substrate of the corresponding elementary sensor (32, 34, 36, 38), between the pixel matrix and the circuit to which the associated conductor (Col, Sel, Vdd, VRst, Rst) is connected.

7. Optical sensor according to any one of the preceding claims, characterized in that the elementary sensors (32, 34, 36, 38) are each formed on a separate substrate (32b, 34b, 36b, 38b).

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