Abstract: The integrated capacitor structure comprises a first branch with a first capacitor (60) and a second branch with a second capacitor (70). The second capacitor (70) has a higher capacitance density and a lower breakdown voltage than the first capacitor (60). The first branch has a shorter RC time constant than the second branch, such that a voltage peak will substantially follow the first branch. This first capacitor (60) has a sufficient capacity to store the charge of the voltage peak. In one embodiment, the second capacitor (70) is a stacked capacitor. The structure is suitable for ESD-protection and may, to this end, additionally comprise diodes (21) and resistors (22).

Abstract: The integrated capacitor structure comprises a first branch with a first capacitor (60) and a second branch with a second capacitor (70). The second capacitor (70) has a higher capacitance density and a lower breakdown voltage than the first capacitor (60). The first branch has a shorter RC time constant than the second branch, such that a voltage peak will substantially follow the first branch. This first capacitor (60) has a sufficient capacity to store the charge of the voltage peak. In one embodiment, the second capacitor (70) is a stacked capacitor. The structure is suitable for ESD-protection and may, to this end, additionally comprise diodes (21) and resistors (22).

Abstract: An image detector includes a sensor matrix with a plurality of sensor elements for converting radiation into electrical charges and with several line conductors. The sensor elements are arranged in columns and rows. Separate sensor elements are coupled to at least one of the line conductors. Separate groups of sensor elements in one column and/or in one row of the matrix are coupled to different line conductors and at least one line conductor is coupled to sensor elements of at least two columns or of at least two rows.

Abstract: The invention relates to a sensor which includes a reference electrode as well as a plurality of sensor elements, each sensor element including a collector electrode and a photoconductor structure which is arranged between the reference electrode and the collector electrodes, as well as a switching element which connects the collector electrode to a read-out lead, the sensor elements being arranged in a matrix of n rows and m columns, where n, m are larger than 1. Correct operation of even the sensor elements in the edge zone of the matrix is achieved, irrespective of the construction of the edge of the photoconductor structure and the reference electrode, in that the matrix is provided with a guard electrode window (9) which is arranged between the read-out lead (5) and the photoconductor structure (6) of the sensor elements (21) constituting the edge of the matrix and extends beyond the edge of the photoconductor structure (6).

Abstract: An x-ray examination apparatus comprises an x-ray image sensor matrix (1) for deriving an initial image signal from the x-ray image. The sensor elements of the x-ray sensor matrix convert incident x-rays into electric charges. These electric charges are read-out and converted into the initial image signal. Further a correction unit (2) is provided for correcting the initial image signal, notably for disturbances due to delayed transferred charges, that have been retained in the sensor elements for some time. The correction unit (2) is provided with a memory which stores correction values. Further the correction provided with a selection unit (5) for selecting appropriate correction values from the memory (3).

Abstract: An x-ray examination apparatus comprises an x-ray image sensor matrix (1) for deriving an initial image signal from the x-ray image. The sensor elements of the x-ray sensor matrix convert incident x-rays into electric charges. These electric charges are read-out and converted into the initial image signal. Further a correction unit (2) is provided for correcting the initial image signal, notably for disturbances due to delayed transferred charges, that have been retained in the sensor elements for some time. The correction unit (2) is provided with a memory which stores correction values. Further the correction provided with a selection unit (5) for selecting appropriate correction values from the memory (3).

Abstract: The so-called memory effect occurring in a device for forming X-ray images by means of an X-ray image converter which includes a photoconductor for converting the X-rays into a charge pattern can be reduced by means of a trapping layer which is provided on at least one of the two sides of the photoconductor and reduces the current of charge carriers injected into the photoconductor from this side.

Abstract: A medical X-ray apparatus is provided with image detector elements 30 which are arranged in a matrix of rows and columns. In order to improve the noise behaviour of the read amplifiers 46 during the reading per row, a plurality of column conductors 36 is provided per column so that the read time is prolonged in proportion to the number of column conductors and the stray capacitance is reduced proportionally. Both steps reduce the noise in known manner. In the case of an integrated implementation, the conductors for driving the reading per row cannot be arranged arbitrarily close to one another because of their mutual capacitance, so that these conductors require a comparatively large surface area.

Abstract: A device for scanning an X-ray image where a previously locally uniformly charged photoconductor (1) is discharged in dependence on the local intensity, utilizing several electrometer probes which are arranged in a row and which line-wise scan the charge pattern of the photoconductor (1) which is successively displaced in the scanning direction, extending perpendicular to the line direction, the probes supplying, for each pixel, an image value which corresponds to a discharge at the relevant pixel. In order to eliminate streaky artefacts, the image values are applied to an analog-to-digital converter (5), the converted values being stored in an image memory (6), there being provided a signal processor (7) which subjects the image values of neighboring pixels in an image line to a low-pass filter function and which subjects the image values of pixels neighboring one another in the scanning direction to a high-pass filter function.

Abstract: An x-ray examination apparatus comprises an x-ray detector with a sensor matrix for deriving an image signal from an x-ray image. The x-ray detector is provided with a scatter grid having a regular pattern of x-ray attenuating partitions. The spatial resolution of the sensor matrix is such that the size of the smallest detectable detail in the x-ray image is larger than the distance between adjacent partitions. In particular the x-ray detector comprises an x-ray sensitive photoconductor layer for converting x-rays into electric charges, separate sensor elements include respective collecting electrodes and a semiconductor cladding layer being disposed between the photoconductor layer and the collecting electrodes. The semiconductor cladding layer has a substantial lateral electric conductivity. For example, the semiconductor cladding layer is a chlorine doped selenium layer, or a selenium, sulphur or telluride doped lead-oxide layer.

Abstract: An x-ray examination apparatus includes an x-ray source for emitting x-rays and an x-ray detector for deriving an image signal from an x-ray image. The x-ray detector has a semiconductor element including one or several sensor elements. Further the x-ray examination apparatus is provided with a bias radiation source for irradiating the x-ray detector with electromagnetic radiation. In particular, the x-ray detector is an x-ray sensor matrix having a multitude of semiconductor sensor elements. Preferably the bias radiation source is arranged to emit infrared radiation.

Abstract: An x-ray image sensor (1) with a lead-oxide photoconductor layer (6) positioned between collecting electrodes (3) and a common electrode (2) is provided with a passivation layer (7) which separates the lead-oxide from the metal of the common electrode to counteract degradation of the photoconductor layer due to chemical reactions between then metal of the common electrode and the lead-oxide. A bias layer (8) is provided between the common electrode (2) and the photoconductor layer (6) and a cladding layer (9) is provided between collecting electrodes (3) and the photoconductor layer (6) so as to avoid injection of charges into the photoconductor layer.

Abstract: In an arrangement of light-sensitive or X-ray sensitive sensors (S.sub.1,1, . . . , S.sub.2048,2048) arranged in a matrix in rows and columns, which sensors produce charge states in dependence upon the amount of incident radiation and each have an electrical switch, for each sensor row a switching line (33.sub.1, . . . , 33.sub.2048) via which the switches (3) can be activated so that the charge states of the sensors of the activated sensor row are read or reset simultaneously via associated read lines (8, 9, 10), there is provided a reset device (30a, 30b) for resetting the charge states of previously read sensor rows, which device activates at least one of the previously read sensor rows, which activates another of the previously read sensor rows after a predetermined number of clock pulses of a reset clock signal (T.sub.32), and which deactivates each activated sensor row a predetermined number of clock pulses after its activation.

Abstract: An image detection device, notably a semiconductor image detection array for detecting x-ray images, is provided wherein perturbations due to phantom-images are substantially mitigated. In such an image detection array incident image carrying radiation is converted into charges. Delayed charge transfer due to trapping of charges in the semiconductor material of radiation sensor elements causes such perturbations. In an image detection device according to the invention a correction circuit is provided which is arranged to form an image correction signal being representative of delayed transferred charges. In a particular embodiment of an image detection device according to the invention the image correction signal is formed as a superposition of exponentially decaying signals of images which were detected before the detection of a currently detected image.

Abstract: The invention relates to an X-ray image detector, comprising a plurality of X-ray-sensitive sensors and having the following features:each sensor comprises a collecting electrode and a switching element which connects the collecting electrode to an output lead;a photoconductor layer is provided between the individual collecting electrodes and a bias electrode;the collecting electrodes form, in conjuction with reference electrodes, capacitances which can be charged by charge carriers generated in the photoconductor. The invention improves the effectiveness of such an X-ray image detector in that either the surface area of the collecting electrodes is increased or the electric field is distorted by a semiconductor layer so that the majority of the charge carriers generated in the photoconductor flow to the collecting electrodes.

Abstract: An X-ray image amplifier tube designed with an input screen having a photocathode and with a detection screen which is opposite the latter and a short distance away for detection of a photo-electron beam which is generated by X-ray input image signals and is amplified in the tube. The detection screen is provided with a conversion coating for converting an image-carrying photo-electron beam into a potential excursion and to this end contains, for example, an amorphous selenium coating or a porous KCl coating. A variable potential can be applied both over the vacuum gap between the photocathode and the conversion coating and over the conversion coating itself and, as a result of this, high image brightness dynamics can be achieved without image disruption.

Abstract: The invention relates to a method of generating X-ray images by means of a photoconductor which is provided on a conductive substrate and whose surface potential can be read by means of probes, and also relates to a device suitable for carrying out the method. In order to avoid image artefacts which could be caused by deviating sensitivities of the probes or by frequency-dependent distortions, after the charging of the photoconductor the substrate potential is varied during a test phase. Test data is generated which correspond to the spatial or temporal variation of the potential on the surface of the photoconductor; from this test data there is formed correction data which is stored in order to correct the image data of a subsequent X-ray exposure.

Abstract: An X-ray examination apparatus includes a sensor matrix (41) with sensors (1) which are arranged in rows and columns and each of which comprises an X-ray sensitive photosensor element (11) and a storage capacitance (12) which is connected parallel thereto. First electrodes of the sensors are connected to a counter-electrode (2) which receives a direct voltage, second electrodes being connected to an electric switch (13) provided for each sensor. For exposure measurement the currents flowing through the counter-electrode (electrodes) (2) and/or the electric switches (13) after the brief closing of the electric switches (13) and before the reading of the charges are used to measure and/or correct the exposure of groups of the sensors during the execution of an X-ray exposure.

Abstract: A matrix of light-sensitive or x-ray sensitive sensors (S.sub.1,1, . . . S.sub.2000,200) are arranged in rows and columns and generate charges in dependence on the amount of incident radiation. The sensors comprise a respective electric switch (3) and are constructed, like the electric switches (3), of thin-film technology. Each sensor row has a switching line (5, 6, . . . , 7) via which the switches can be activated so that the charges of the relevant activated sensor row are simultaneously output via read lines (8, 9, . . . , 10, . . . ). Transfer means convert the signals read in parallel into a serial output signal; in order to achieve an as favorable as possible noise behavior. An amplifier (11, 12, . . . , 13) is in each read line and is constructed as a silicon crystal and precedes the transfer means. During the read operations, the amplifiers simplify the signals read from the sensors (S.sub.1.1, . . . S.sub.2000,2000) connected to the relevant read line (8, 9, . . . , 10, . . . ).

Abstract: A photodiode radiation sensor sensitive to luminous or x-ray radiation, has an inherent capacitance which is charged by the radiation. The charge is read out by a switching diode. The diode is placed in its conductive state by an auxiliary voltage and is switched off after the read-out process. The quantity of charge flowing during the read-out process is measured and used to determine the quantity of incident radiation. To measure relatively small quantities of charge, a voltage is coupled in when the auxiliary voltage is switched on to place the switching diode in a more strongly conducting state so that during the read-out process a larger quantity of charge flows away.