WO1996034416A1 - Active matrix x-ray imaging array - Google Patents
Active matrix x-ray imaging array Download PDFInfo
- Publication number
- WO1996034416A1 WO1996034416A1 PCT/CA1995/000247 CA9500247W WO9634416A1 WO 1996034416 A1 WO1996034416 A1 WO 1996034416A1 CA 9500247 W CA9500247 W CA 9500247W WO 9634416 A1 WO9634416 A1 WO 9634416A1
- Authority
- WO
- WIPO (PCT)
- Prior art keywords
- thin film
- film transistors
- respective ones
- pixel electrodes
- active matrix
- Prior art date
Links
- 239000011159 matrix material Substances 0.000 title claims abstract description 51
- 238000003384 imaging method Methods 0.000 title claims abstract description 26
- 239000003990 capacitor Substances 0.000 claims abstract description 36
- 238000003860 storage Methods 0.000 claims abstract description 36
- 238000002601 radiography Methods 0.000 claims abstract description 18
- 230000005684 electric field Effects 0.000 claims abstract description 16
- 238000002594 fluoroscopy Methods 0.000 claims abstract description 10
- 239000010409 thin film Substances 0.000 claims description 69
- 230000005855 radiation Effects 0.000 claims description 36
- 238000001514 detection method Methods 0.000 claims description 23
- 235000011194 food seasoning agent Nutrition 0.000 claims description 5
- 239000012212 insulator Substances 0.000 claims description 5
- 238000002955 isolation Methods 0.000 claims description 5
- 230000001846 repelling effect Effects 0.000 claims description 4
- 239000004065 semiconductor Substances 0.000 claims description 4
- 238000009413 insulation Methods 0.000 claims description 3
- 230000001186 cumulative effect Effects 0.000 claims 6
- 230000002940 repellent Effects 0.000 claims 3
- 239000005871 repellent Substances 0.000 claims 3
- 239000004020 conductor Substances 0.000 claims 2
- 230000009977 dual effect Effects 0.000 abstract description 5
- 238000010521 absorption reaction Methods 0.000 abstract description 3
- 238000009826 distribution Methods 0.000 abstract description 3
- 239000011669 selenium Substances 0.000 description 24
- BUGBHKTXTAQXES-UHFFFAOYSA-N Selenium Chemical compound [Se] BUGBHKTXTAQXES-UHFFFAOYSA-N 0.000 description 11
- 229910052711 selenium Inorganic materials 0.000 description 11
- 238000002059 diagnostic imaging Methods 0.000 description 10
- OAICVXFJPJFONN-UHFFFAOYSA-N Phosphorus Chemical compound [P] OAICVXFJPJFONN-UHFFFAOYSA-N 0.000 description 9
- 238000002207 thermal evaporation Methods 0.000 description 8
- 229910021417 amorphous silicon Inorganic materials 0.000 description 7
- 229910052751 metal Inorganic materials 0.000 description 7
- 239000002184 metal Substances 0.000 description 7
- 238000000034 method Methods 0.000 description 7
- 238000003491 array Methods 0.000 description 6
- 230000000903 blocking effect Effects 0.000 description 4
- 238000004519 manufacturing process Methods 0.000 description 4
- 238000005259 measurement Methods 0.000 description 4
- 238000000206 photolithography Methods 0.000 description 4
- 238000004544 sputter deposition Methods 0.000 description 4
- UHYPYGJEEGLRJD-UHFFFAOYSA-N cadmium(2+);selenium(2-) Chemical compound [Se-2].[Cd+2] UHYPYGJEEGLRJD-UHFFFAOYSA-N 0.000 description 3
- 238000011161 development Methods 0.000 description 3
- 239000003989 dielectric material Substances 0.000 description 3
- 238000002347 injection Methods 0.000 description 3
- 239000007924 injection Substances 0.000 description 3
- 238000005334 plasma enhanced chemical vapour deposition Methods 0.000 description 3
- 238000000623 plasma-assisted chemical vapour deposition Methods 0.000 description 3
- 230000008569 process Effects 0.000 description 3
- 238000011160 research Methods 0.000 description 3
- 229910052581 Si3N4 Inorganic materials 0.000 description 2
- 230000002159 abnormal effect Effects 0.000 description 2
- 238000005452 bending Methods 0.000 description 2
- 238000002591 computed tomography Methods 0.000 description 2
- 238000000151 deposition Methods 0.000 description 2
- 230000008021 deposition Effects 0.000 description 2
- 238000013461 design Methods 0.000 description 2
- 230000007774 longterm Effects 0.000 description 2
- 229910021421 monocrystalline silicon Inorganic materials 0.000 description 2
- 240000000136 Scabiosa atropurpurea Species 0.000 description 1
- 244000082988 Secale cereale Species 0.000 description 1
- 238000000333 X-ray scattering Methods 0.000 description 1
- 229910052782 aluminium Inorganic materials 0.000 description 1
- 238000013459 approach Methods 0.000 description 1
- 238000000149 argon plasma sintering Methods 0.000 description 1
- 238000005513 bias potential Methods 0.000 description 1
- 230000008859 change Effects 0.000 description 1
- 238000006243 chemical reaction Methods 0.000 description 1
- 239000011248 coating agent Substances 0.000 description 1
- 238000000576 coating method Methods 0.000 description 1
- 230000002860 competitive effect Effects 0.000 description 1
- 238000004195 computer-aided diagnosis Methods 0.000 description 1
- 238000010276 construction Methods 0.000 description 1
- 239000013256 coordination polymer Substances 0.000 description 1
- 230000008878 coupling Effects 0.000 description 1
- 238000010168 coupling process Methods 0.000 description 1
- 238000005859 coupling reaction Methods 0.000 description 1
- 238000003745 diagnosis Methods 0.000 description 1
- 238000009792 diffusion process Methods 0.000 description 1
- 239000003814 drug Substances 0.000 description 1
- 229940079593 drug Drugs 0.000 description 1
- 230000000694 effects Effects 0.000 description 1
- 230000002349 favourable effect Effects 0.000 description 1
- 239000000835 fiber Substances 0.000 description 1
- 230000004313 glare Effects 0.000 description 1
- 239000011521 glass Substances 0.000 description 1
- 229910052738 indium Inorganic materials 0.000 description 1
- APFVFJFRJDLVQX-UHFFFAOYSA-N indium atom Chemical compound [In] APFVFJFRJDLVQX-UHFFFAOYSA-N 0.000 description 1
- 239000011810 insulating material Substances 0.000 description 1
- 230000002427 irreversible effect Effects 0.000 description 1
- 238000002595 magnetic resonance imaging Methods 0.000 description 1
- 238000009607 mammography Methods 0.000 description 1
- 239000000463 material Substances 0.000 description 1
- 238000012986 modification Methods 0.000 description 1
- 230000004048 modification Effects 0.000 description 1
- 230000006855 networking Effects 0.000 description 1
- 238000009206 nuclear medicine Methods 0.000 description 1
- 230000003287 optical effect Effects 0.000 description 1
- 238000007254 oxidation reaction Methods 0.000 description 1
- 238000002360 preparation method Methods 0.000 description 1
- 230000002035 prolonged effect Effects 0.000 description 1
- 238000001959 radiotherapy Methods 0.000 description 1
- 230000035945 sensitivity Effects 0.000 description 1
- 239000000758 substrate Substances 0.000 description 1
- 238000012546 transfer Methods 0.000 description 1
- 238000002604 ultrasonography Methods 0.000 description 1
Classifications
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
- H01L27/00—Devices consisting of a plurality of semiconductor or other solid-state components formed in or on a common substrate
- H01L27/14—Devices consisting of a plurality of semiconductor or other solid-state components formed in or on a common substrate including semiconductor components sensitive to infrared radiation, light, electromagnetic radiation of shorter wavelength or corpuscular radiation and specially adapted either for the conversion of the energy of such radiation into electrical energy or for the control of electrical energy by such radiation
- H01L27/144—Devices controlled by radiation
- H01L27/146—Imager structures
- H01L27/14665—Imagers using a photoconductor layer
Definitions
- This invention relates in general to medical diagnostic imaging systems, and more particularly to a selenium active matrix universal readout array imager.
- CT computed tomography
- MRI magnetic resonance imaging
- digital radiology provides significant advantages over its analog counter-part, such as: easy comparison of radiological images with those obtained from other imaging modalities; the ability to provide image networking within a hospital for remote access and archiving; facilitating computer aided diagnosis by radiologists; and facilitating teleradiology (ie. remote diagnostic service to poorly populated regions from a central facility) .
- Digital systems based on the use of X-ray image intensifiers suffer from the following disadvantages: the bulky nature of the intensifier often impedes the clinician by limiting access to the patient and prevents the acquisition of important radiographic views; loss of image contrast due to X-ray and light scattering (i.e. veiling glare) ; and geometric (pin cushion) distortion on the image due principally to the curved input phosphor.
- Another prior art X-ray imaging modality which is currently experiencing renewed interest is the use of amorphous selenium photoconductors as an alternative to phosphors.
- Xeroradiography i.e.
- amorphous selenium (a-Se) plates which are read out with toner was a technical and commercial success in the early 1970 , s. Xeroradiography is no longer commercially competitive. This is believed to be because of the toner readout method, and not because of the underlying properties of a-Se.
- Commercial as well as scientific interest in a-Se has recently revived. For example, Philips has announced the commercial availability of an a-Se drum scanner for chest radiography based on earlier work at its research laboratories in Aachen. Kodak uses an a-Se plate readout with a phosphor coated toner and laser scanner for the preparation of highly detailed mam ography images which are free from significant artifacts.
- a better method for eliminating blurring involves using a structureless photoconductor to detect X-rays.
- X-rays interacting in the photoconductor release electron-hole pairs which are drawn directly to the surfaces of the photoconductor by an applied electric field.
- the latent charge image on the photoconductor surface is therefore not blurred significantly even if the photoconductor layer is made thick enough to absorb most incident X-rays.
- Amorphous selenium (a-Se) is the most highly developed photoconductor for X-ray applications. Its amorphous state maintains uniform characteristics to very fine levels over large areas.
- a large area detector is essential in radiography since no means are provided to focus the X-rays, thereby necessitating a shadow X-ray image which is larger than the body part to be imaged.
- a phosphor screen (preferably a structured Csl layer) is used to absorb X- rays, and the resultant light photons are detected by an active matrix array with a single photodiode and transistor at each pixel.
- a digital detector which performs all of the currently available radiological modalities, radiography (including rapid sequence radiography) and fluoroscopy.
- the detector comprises a large area, flat panel which easily fits into the conventional X-ray room bucky tray.
- the detector utilizes a layer of photoconductor (ie. a-Se in the preferred embodiment) to detect X-rays and convert the X-ray energy to charge, and an active matrix TFT array in the form of a very large area integrated circuit, for readout of the charge.
- a dual gate structure is utilized for providing high voltage protection of the TFTs.
- the additional gate is formed as an extension of the pixel electrode, and overlies a predetermined thickness of dielectric over the semiconductor channel. When excessive charge is collected by the electrode, the TFT turns ON so that a high leakage current drains away the excess charge on the pixel electrode.
- an integrated pixel storage capacitor is provided for enhanced absorption of X-ray energy with low pixel voltage, low leakage current and hence a large charge leakage time constant.
- the integrated pixel storage capacitor is created by overlapping the pixel electrode with an adjacent gate line or a separate ground line of the active matrix readout array.
- image charge collection efficiency is improved by manipulating the electric field distribution in the photoconductor layer so that image charges land on the pixel electrodes, and not on the TFT readout devices.
- a photo-timer is integrated into the imaging detector for measuring X-ray exposure.
- the system of the preferred embodiment provides higher resolution images than phosphor based systems, even those using structured Csl.
- the signal-to-noise ratio of the prior art MASDA system and the system of the preferred embodiment are essentially identical since the X-ray-to- charge conversion gain is the same for both (assuming Csl and a-Si:H for MASDA and a-Se for the system of the preferred embodiment) .
- the overall image quality of the system according to the present invention is believed to be considerably better than that produced using the prior MASDA device.
- the requirements for manufacture of the system of the preferred embodiment are favourable when compared to the prior art MASDA system.
- MASDA requires a Csl structure which is more difficult in principle to manufacture than a uniform layer of a-Se.
- X-rays are converted directly to electrons by a-Se, the need for photodiodes at each pixel is eliminated and the active matrix array can be simplified. This leads to further simplifications in the system of the present invention, as compared to the prior art MASDA device, thereby resulting in more economical manufacturing.
- Figure 1A is a schematic plan view of the imaging array according to the preferred embodiment
- Figure IB is an equivalent circuit for the imaging array of Figure 1A;
- Figure 2 is cross sectional view through a single pixel of the array shown in Figure 1;
- Figure 3 shows the I-V characteristics of the high voltage protected TFT according to the present invention
- Figure 4A is a cross sectional view through two pixels of the array shown in Figure 1, illustrating improved fill factor by bending electric field lines using guard rails, in accordance with the preferred embodiment
- Figure 4B is a plan view of the top layer of the array showing the disposition of the guard rails
- Figure 4C shows an alternative embodiment in which fill factor is improved by the bending of electric field lines using the charge trapping properties of the top dielectric material between pixel electrodes
- Figure 5 is a plan view of an arrangement of bias electrode for biasing a photoconductor layer of the preferred embodiment and providing dose measurements in accordance with an alternative embodiment
- FIGS 6A and 6B are two alternative cross- sectional views through the line VI - VI in Figure 5; and Figure 7 is a schematic of a photo-timer and circuit arrangement for dose/dose rate measurement, according to the embodiment of Figures 5 and 6.
- an active matrix 10 is shown comprising a plurality of pixels, each comprising a pixel electrode 12, storage capacitor 14 and thin film transistor (TFT) 16.
- An external scanning control circuit 18 turns on the TFTs 16 one row at a time via a plurality of control lines 19, for transferring the image charge from the pixels to a plurality of data lines 20, and then to respective external charge amplifiers 22.
- the input (virtual ground) of the charge amplifiers 22 resets the potential at each pixel electrode 12.
- the resulting amplified signal for each row is multiplexed by a parallel-to-serial converter or multiplexer 24, and then transmitted to an analog-to- digital converter or digitizer 26.
- Each TFT 16 comprises 3 electrical connections: the drain (D) is connected to the pixel electrode 12 and pixel storage capacitor 14; the source (S) is connected to a common data line 20 shared by all TFTs of the same column, and also to an external charge sensitive amplifier 22; and the gate (G) is used for control of the "on” and “off” state of the TFT 16. Usually, 10V and -5V is applied to turn on and off the TFT 16 respectively.
- the scanning control circuit 18 may be fabricated as a single crystal silicon integrated circuit which is wire bonded to the active matrix TFT array.
- the charge amplifiers 22 and multiplexer 24 may also be fabricated as a single crystal silicon integrated circuit which is wire bonded to the active matrix array.
- a metal layer (preferably Cr or Al) is deposited (by thermal evaporation or sputtering) on a glass substrate 28 and patterned using photolithography to form the gate regions (G) for the array of TFTs.
- the gate line of an adjacent pixel may be extended so that the gate line and the pixel electrode 12 form an integrated pixel storage capacitor 14 with insulating layer 30 extending therebetween.
- separate ground return electrodes for storage capacitor may be formed between gate electrode lines on the first metal layer.
- the insulating layer 30 is deposited using PECVD (Plasma Enhanced Chemical Vapour Deposition) or thermal evaporation.
- the insulating material can be Si0 2 , Si 3 N 4 , or alternate layers of both.
- the thickness of the layer is typically 0.1 - 0.5 ⁇ m.
- the drain (D) and source (S) metal layers are deposited (by thermal evaporation or sputtering) and patterned using photolithography to form drain and source contact pads for the TFT, the pixel electrodes and source (i.e. data) lines.
- the preferred material for the D and S contact pads is Cr, and an extra coating of Al is preferably added to the source lines to reduce the source line resistance.
- a semiconductor layer 32 being several hundred angstroms thick, is deposited (e.g. using thermal evaporation or sputtering in the case of CdSe) and then patterned using photolithography to form the TFT channel (e.g. 30 ⁇ m wide and 50 ⁇ m long, although the illustrated TFT geometry represents only one possible embodiment of the invention) .
- the above-described deposition procedure is used for the drain, and source metal and semiconductor fabrication steps for a bottom D and S contact TFT structure.
- the two deposition steps can be reversed to form a top contact structure.
- a dielectric layer 34 (Si0 2 , Si 3 N 4 or alternate layers of both) is deposited (using PECVD or thermal evaporation) with a thickness of 0.3 - 5 ⁇ m. Then, the dielectric on top of the pixel electrode is etched away to expose the pixel electrode.
- the final top metal layer (preferably Al, or ITO) of the TFT is deposited using sputtering or thermal evaporation, and patterned using photolithography to form the pixel electrode 12 (which is the bottom pixel electrode since the dielectric in this region has been etched away) .
- the pixel electrode 12 extends over the top gate dielectric layer 34 so as to form a dual gate TFT structure.
- a blocking layer may be formed by thermal oxidization the top metal (Al) layer for preventing negative charge injection from the pixel electrode to the X-ray photoconductor.
- a uniform layer of X-ray sensitive photoconductor 36 is then directly deposited on the surface of the active matrix by thermal evaporation, to a thickness of approximately 500 ⁇ m.
- the photoconductor is fabricated from amorphous selenium (a-Se) .
- a top bias electrode 38 is deposited (e.g. by thermal evaporation) onto the photoconductor layer 36 with appropriate blocking contact so that charge generated in the bulk of the photoconductor can flow to the bias electrode, with no charge injection from the bias electrode into the photoconductor.
- Several types of metal may form the blocking contact with selenium, such as Au, Indium, etc.
- An alternative embodiment is to deposit a thin layer (several hundred angstroms) of insulator (e.g. Ce0 2 ) on the surface of the selenium before the bias electrode is deposited, wherein the thin insulating layer serves as a blocking layer.
- the selenium layer 36 and top bias electrode 38 are shown schematically as a photodiode connected to a high bias voltage (HV) at the cathode of each pixel.
- HV high bias voltage
- the X-ray energy is absorbed by the X-ray photoconductor 36 and electron-hole pairs are created.
- the radiation generated charges are drawn to the surfaces of the photoconductor 36 and collected on pixel electrode 12. The difference in charge at each pixel represents the X- ray image.
- the pixel electrode is connected to the drain (D) of the TFT 16. During each readout, the potential of the pixel electrode is reset, through the TFT, to a ground potential by the virtual ground input of the charge amplifier 22.
- a high voltage is constantly applied to the bias electrode 38 and the imaging detector is scanned in real time (i.e. 30 frames per second) .
- the images are acquired continuously in every 1/30 second frame and are processed and displayed in real time.
- a high voltage is applied to the bias electrode 38 and the scanning is suspended (i.e. all TFTs 16 are turned off) during X-ray exposure. Scanning is resumed immediately after the exposure in order to readout the image.
- the photoconductor layer 36 needs to be of a thickness in the order of 500 ⁇ m in order to absorb most of the incident X-rays.
- the bias voltage applied to electrode 38 must be in the order of 5000 volts under an electric field of lOV/ ⁇ m. Under abnormal conditions (e.g. a false prolonged X-ray exposure when all TFTs 16 are turned off) , the potential on each pixel (V p ) can reach a damaging high value (e.g.
- the CdSe TFTs 16 of the preferred embodiment can maintain normal functions at V P up to approximately 200 volts. Thus, it is necessary to ensure that even under false, abnormal conditions, V P does not exceed 100 volts.
- a dual gate structure is utilized to protect the TFT 16 from high voltage damage.
- the pixel electrode 12 which is connected to the TFT drain (D)
- the top dielectric layer 34 is usually 5 to 10 times the thickness of the bottom gate dielectric layer for high voltage protection at a pixel potential of 100 volts.
- Figure 3 shows the I D -VQ characteristic curve for a dual gate TFT at different values of V P .
- V P normal imaging conditions
- the bottom gate control pulse causes the TFT 16 to turn on and off correctly.
- V P exceeds 100 volts
- the bottom gate control pulse is no longer able to turn off TFT 16. In this case, the high leakage current drains away the excess charge on the pixel electrode 12 and V P never reaches a dangerously high potential.
- V ⁇ ⁇ , and dielectric thickness may be expressed as follows: where e t is the dielectric constant of dielectric layer 34, ⁇ is the thickness of dielectric layer 34, V ⁇ ,. ⁇ is the maximum voltage to be applied to the pixel, e* dielectric constant of the dielectric layer 30, and d 4 is the thickness thereof.
- V ⁇ usually -5V
- V ft is a constant representing the minimum voltage which when applied to the bottom gate (G) will turn on the TFT when V p «0.
- the dielectric layer 34 will have a thickness of 1-5 ⁇ m, given the same dielectric as the dielectric layer 30.
- an integrated pixel storage capacitance is provided on the TFT active matrix array, by overlapping the pixel electrode 12 with the gate line (G) of an adjacent pixel, as shown in Figure l and in Figure 2 on the left where storage capacitor 14 is formed by overlapping pixel electrode 12 with an extension of the gate line (G) of an adjacent pixel.
- a separate ground line may be utilized as an alternative to overlapping the pixel electrode 12 with the adjacent gate line.
- a large pixel capacitance results from the thin insulating layer 30 (typically 0.1 - 0.5 ⁇ m) , resulting in a storage capacitance Cg- in the range of 0.5 - l pF, which is 20 times larger than C ⁇ D , and two orders of magnitude larger than the capacitance of the photoconductor layer 36.
- the value of Cg- is achieved by extending the pattern of the gate electrode (or a separate ground line) , under the region of each pixel electrode 12 when the size of the pixel electrode is larger than 200 ⁇ m (e.g. for fluoroscopy and general radiography) .
- the pixel size must be smaller (in the order of 50 ⁇ m) , thinning of the insulator is needed in addition to extending the gate electrode.
- the large integrated pixel storage capacitance Cg- ensures, firstly, that the pixel voltage V P does not rise more than 2V/pC with image charge, and thus does not reach a damagingly high potential under diagnostic X-ray exposure levels. Secondly, the voltage on the pixel electrodes returns to near ground potential after the TFTs 16 are turned off, thereby ensuring a low leakage current. Thirdly, the charge leakage time constant is approximately 10 seconds, and thus does not cause any significant signal loss for radiography applications.
- Figure 4 a cross sectional view, is provided similar to Figure 2, through two adjacent pixels. However, the section of Figure 2 extends through storage capacitor 14, while the section of Figure 4 does not.
- a plurality of parallel rails 40 are deposited as a grid adjacent the pixel electrodes 12, so as to overlay the source lines (S) .
- Image charge collection efficiency in an active matrix sensor array is controlled by the fill factor (i.e. the fraction of the area of each pixel that is occupied by the pixel electrode 12) .
- the fill factor of a typical CdSe TFT array is approximately 80% for a 200 ⁇ m square pixel. Most of the remainder of each pixel is occupied by the source lines (S) .
- the electric field distribution in the photoconductive layer 36 may be manipulated so that image charges only land on the pixel electrodes 12, and not on the source lines (S) .
- the field lines 42 may be caused to bend toward the pixel electrodes 12 and thus increase the effective fill factor.
- the potential applied to the grid 40 must be sufficient to cause a noticeable increase in charge collection efficiency of the pixel electrode 12 (e.g. typically in the order of several hundred volts) .
- a plan view of the grid 40 is shown in Figure 4B.
- the charge trapping properties of the top dielectric material of the pixel electrodes may be utilized to bend the electric field. More particularly, after the construction of the detector is completed, a seasoning process is performed. To perform this seasoning, the detector is exposed to large doses of X- rays (or visible light if the top bias electrode 38 is semitransparent, e.g. Au) , with the TFTs 16 all turned on and with an electric field applied to the selenium photoconductor 36. The holes created in the photoconductor 36 are drawn to the bottom surface thereof, either landing on the pixel electrodes 12 or becoming trapped by the dielectric material 34 between pixel electrodes.
- X- rays or visible light if the top bias electrode 38 is semitransparent, e.g. Au
- means for measuring X-ray exposure dosages may be incorporated into the design of the active matrix flat panel detector so as to perform photo timing functions simultaneously with image detection.
- Figure 5 shows the top view of top sensor bias electrode 38 which, as discussed above, is connected to a high voltage power supply.
- a plurality of smaller electrodes 42 (e.g. preferably 3 for chest radiography) provide regions of X-ray dose measurement.
- the bias electrode 38 is connected to a DC high voltage (HV) power supply.
- Each phototimer electrode 42 is connected to its own dose/dose rate measurement circuit.
- each electrode 42 is connected to the inverting input of an amplifier 71 which is powered by a pair of isolated power supplies, for providing +15V and -15V with the ground reference set at the DC HV bias potential applied to the photoconductor 36.
- the inverting input of amplifier 71 is at the same potential as its non-inverting input, which is connected to the DC HV bias. Therefore, electrode 42 is at the same potential as electrode 38.
- the X-ray generator When the amplifier 71 output voltage (also monitored by a circuit in the X- ray generator) reaches a preset value (i.e. proportional to the preset X-ray exposure dosage) , the X-ray generator will turn off the X-rays.
- the imaging mode (fluoroscopy or radiography) is selected electronically by a relay 77. Since the relay 77 is connected to the amplifier circuit, it has to be operated by a control signal with the same reference (i.e. DC HV potential).
- a gap 43 is provided for isolating the phototimer bias electrodes 42 from the common top bias electrode 38, whereas in the cross-sectional view of the Figure 6B embodiment no gap for electric field application is shown (when viewed in plan) , and the necessary isolation between electrodes is provided by an additional insulation layer 44.
Abstract
Description
Claims
Priority Applications (5)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
JP53205096A JP4063870B2 (en) | 1995-04-28 | 1995-04-28 | Active matrix X-ray imaging array |
PCT/CA1995/000247 WO1996034416A1 (en) | 1995-04-28 | 1995-04-28 | Active matrix x-ray imaging array |
EP95916537A EP0823132B1 (en) | 1995-04-28 | 1995-04-28 | Active matrix x-ray imaging array |
US08/952,325 US5962856A (en) | 1995-04-28 | 1995-04-28 | Active matrix X-ray imaging array |
DE69511292T DE69511292T2 (en) | 1995-04-28 | 1995-04-28 | ACTIVE X-RAY IMAGE MATRIX |
Applications Claiming Priority (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
PCT/CA1995/000247 WO1996034416A1 (en) | 1995-04-28 | 1995-04-28 | Active matrix x-ray imaging array |
Publications (1)
Publication Number | Publication Date |
---|---|
WO1996034416A1 true WO1996034416A1 (en) | 1996-10-31 |
Family
ID=4173079
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
PCT/CA1995/000247 WO1996034416A1 (en) | 1995-04-28 | 1995-04-28 | Active matrix x-ray imaging array |
Country Status (5)
Country | Link |
---|---|
US (1) | US5962856A (en) |
EP (1) | EP0823132B1 (en) |
JP (1) | JP4063870B2 (en) |
DE (1) | DE69511292T2 (en) |
WO (1) | WO1996034416A1 (en) |
Cited By (13)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
DE19833919A1 (en) * | 1998-07-28 | 2000-02-10 | Siemens Ag | High-efficiency, photoconductor-based, circular-array X-ray detector, avoids inefficiencies associated with scintillation detectors, to form compact unit suitable for use in medical tomography or transport security |
JP2000065933A (en) * | 1998-08-26 | 2000-03-03 | Fuji Photo Film Co Ltd | Radiation image detecting apparatus |
EP0967655A3 (en) * | 1998-06-26 | 2000-06-28 | FTNI Inc. | Indirect x-ray image detector for radiology |
US6239439B1 (en) | 1997-11-28 | 2001-05-29 | Canon Kabushiki Kaisha | Radiation detecting device and radiation detecting method |
US6667481B2 (en) | 2000-03-09 | 2003-12-23 | Sharp Kabushiki Kaisha | Two-dimensional image sensor |
WO2004095833A1 (en) | 2003-04-22 | 2004-11-04 | Canon Kabushiki Kaisha | Photoelectric conversion device and radiation photography apparatus |
US7122804B2 (en) | 2002-02-15 | 2006-10-17 | Varian Medical Systems Technologies, Inc. | X-ray imaging device |
WO2007017470A1 (en) * | 2005-08-08 | 2007-02-15 | Siemens Aktiengesellschaft | Flat screen detector |
EP1813096A1 (en) * | 2004-10-20 | 2007-08-01 | Simon Fraser University | High gain digital imaging system |
US7775712B1 (en) * | 2006-06-13 | 2010-08-17 | Virtual Imaging, Inc. | Modified grid cabinet assembly |
US7791032B2 (en) | 2003-08-12 | 2010-09-07 | Simon Fraser University | Multi-mode digital imaging apparatus and system |
US8199236B2 (en) | 2007-09-11 | 2012-06-12 | Simon Fraser University/Industry Liason Office | Device and pixel architecture for high resolution digital |
US9364191B2 (en) | 2013-02-11 | 2016-06-14 | University Of Rochester | Method and apparatus of spectral differential phase-contrast cone-beam CT and hybrid cone-beam CT |
Families Citing this family (58)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US6331274B1 (en) | 1993-11-01 | 2001-12-18 | Nanogen, Inc. | Advanced active circuits and devices for molecular biological analysis and diagnostics |
DE69623659T2 (en) * | 1996-05-08 | 2003-05-08 | Ifire Technology Inc | HIGH-RESOLUTION FLAT SENSOR FOR RADIATION IMAGING SYSTEM |
US6486470B2 (en) | 1998-11-02 | 2002-11-26 | 1294339 Ontario, Inc. | Compensation circuit for use in a high resolution amplified flat panel for radiation imaging |
FR2787960B1 (en) * | 1998-12-23 | 2001-03-16 | Thomson Tubes Electroniques | IMAGE DETECTOR WITH BUILT-IN DATA ACQUISITION AMPLIFIERS |
US6453008B1 (en) * | 1999-07-29 | 2002-09-17 | Kabushiki Kaisha Toshiba | Radiation detector noise reduction method and radiation detector |
WO2001033921A1 (en) * | 1999-11-03 | 2001-05-10 | Sterling Diagnostics Imaging, Inc. | System for converting conventional x-ray apparatus to a digital imaging device |
FI111759B (en) * | 2000-03-14 | 2003-09-15 | Planmed Oy | Arrangement with sensor and procedure for digital x-ray imaging |
JP2001284628A (en) * | 2000-03-29 | 2001-10-12 | Shindengen Electric Mfg Co Ltd | X-ray detector |
US6956216B2 (en) * | 2000-06-15 | 2005-10-18 | Canon Kabushiki Kaisha | Semiconductor device, radiation detection device, and radiation detection system |
JP4004761B2 (en) * | 2001-01-18 | 2007-11-07 | シャープ株式会社 | Flat panel image sensor |
US6489619B2 (en) | 2001-04-27 | 2002-12-03 | Xerox Corporation | Pixel circuit with selectable capacitor load for multi-mode X-ray imaging |
US7053967B2 (en) | 2002-05-23 | 2006-05-30 | Planar Systems, Inc. | Light sensitive display |
WO2003073159A1 (en) | 2002-02-20 | 2003-09-04 | Planar Systems, Inc. | Light sensitive display |
US7023503B2 (en) * | 2002-02-20 | 2006-04-04 | Planar Systems, Inc. | Image sensor with photosensitive thin film transistors |
US7009663B2 (en) | 2003-12-17 | 2006-03-07 | Planar Systems, Inc. | Integrated optical light sensitive active matrix liquid crystal display |
DE10219927A1 (en) * | 2002-05-03 | 2003-11-20 | Philips Intellectual Property | X-ray examination device with a dose measuring device |
DE60333410D1 (en) * | 2003-01-10 | 2010-08-26 | Scherrer Inst Paul | Image pickup device for photon counting |
DE602004012961D1 (en) * | 2003-01-15 | 2008-05-21 | Philips Intellectual Property | LEAGONIC ELEMENTS BASED ON DIAGONAL LINE GUIDANCE |
JP4266656B2 (en) | 2003-02-14 | 2009-05-20 | キヤノン株式会社 | Solid-state imaging device and radiation imaging device |
US20080084374A1 (en) | 2003-02-20 | 2008-04-10 | Planar Systems, Inc. | Light sensitive display |
KR100523671B1 (en) * | 2003-04-30 | 2005-10-24 | 매그나칩 반도체 유한회사 | Cmos image sensor with double gateoxide and method of fabricating the same |
US7132667B2 (en) * | 2004-02-11 | 2006-11-07 | General Electric Company | Method and apparatus for improved data acquisition using a solid state digital X-ray detector |
US7773139B2 (en) | 2004-04-16 | 2010-08-10 | Apple Inc. | Image sensor with photosensitive thin film transistors |
US7498585B2 (en) * | 2006-04-06 | 2009-03-03 | Battelle Memorial Institute | Method and apparatus for simultaneous detection and measurement of charged particles at one or more levels of particle flux for analysis of same |
US7317190B2 (en) * | 2004-09-24 | 2008-01-08 | General Electric Company | Radiation absorbing x-ray detector panel support |
US7189972B2 (en) * | 2004-10-04 | 2007-03-13 | General Electric Company | X-ray detector with impact absorbing cover |
US7046764B1 (en) | 2004-10-04 | 2006-05-16 | General Electric Company | X-ray detector having an accelerometer |
US7866163B2 (en) * | 2004-10-04 | 2011-01-11 | General Electric Company | Radiographic detector docking station with dynamic environmental control |
US7342998B2 (en) * | 2004-11-18 | 2008-03-11 | General Electric Company | X-ray detector quick-connect connection system |
US7581885B2 (en) * | 2004-11-24 | 2009-09-01 | General Electric Company | Method and system of aligning x-ray detector for data acquisition |
US7381964B1 (en) | 2004-11-24 | 2008-06-03 | General Electric Company | Method and system of x-ray data calibration |
US7456409B2 (en) * | 2005-07-28 | 2008-11-25 | Carestream Health, Inc. | Low noise image data capture for digital radiography |
US7884438B2 (en) * | 2005-07-29 | 2011-02-08 | Varian Medical Systems, Inc. | Megavoltage imaging with a photoconductor based sensor |
US7259377B2 (en) * | 2005-12-15 | 2007-08-21 | General Electric Company | Diode design to reduce the effects of radiation damage |
CA2572713C (en) * | 2006-01-18 | 2014-09-30 | Sunnybrook And Women's College And Health Sciences Centre | Cerenkov x-ray detector for portal imaging |
US7474731B2 (en) * | 2006-08-29 | 2009-01-06 | Siemens Medical Solutions Usa, Inc. | Systems and methods for adaptive image processing using acquisition data and calibration/model data |
JP2008098390A (en) * | 2006-10-12 | 2008-04-24 | Fujifilm Corp | Radiation image detector and its driving method |
JP2008098391A (en) * | 2006-10-12 | 2008-04-24 | Fujifilm Corp | Radiation image detector |
JP5280671B2 (en) * | 2006-12-20 | 2013-09-04 | 富士フイルム株式会社 | Image detector and radiation detection system |
JP5107747B2 (en) * | 2007-03-09 | 2012-12-26 | 富士フイルム株式会社 | Radiation image detector |
US8430563B2 (en) * | 2009-12-22 | 2013-04-30 | Real Time Imaging Technologies, Llc | Dental fluoroscopic imaging system |
US8847169B2 (en) | 2010-05-25 | 2014-09-30 | The Hong Kong University Of Science And Technology | Quantum-limited highly linear CMOS detector for computer tomography |
US9310923B2 (en) | 2010-12-03 | 2016-04-12 | Apple Inc. | Input device for touch sensitive devices |
US8638320B2 (en) | 2011-06-22 | 2014-01-28 | Apple Inc. | Stylus orientation detection |
US8928635B2 (en) | 2011-06-22 | 2015-01-06 | Apple Inc. | Active stylus |
US9329703B2 (en) | 2011-06-22 | 2016-05-03 | Apple Inc. | Intelligent stylus |
FR2977977B1 (en) * | 2011-07-13 | 2013-08-30 | Trixell | METHOD FOR CONTROLLING A PHOTOSENSITIVE DETECTOR BY AUTOMATIC DETECTION OF INCIDENT RADIATION |
US8895343B2 (en) | 2012-04-10 | 2014-11-25 | Drs Rsta, Inc. | High density capacitor integrated into focal plane array processing flow |
WO2013188498A2 (en) * | 2012-06-12 | 2013-12-19 | Arizona Board Of Regents Acting For And On Behalf Of Arizona State University | Imaging system and methods of manufacturing and using the same |
US9557845B2 (en) | 2012-07-27 | 2017-01-31 | Apple Inc. | Input device for and method of communication with capacitive devices through frequency variation |
US9652090B2 (en) | 2012-07-27 | 2017-05-16 | Apple Inc. | Device for digital communication through capacitive coupling |
US9176604B2 (en) | 2012-07-27 | 2015-11-03 | Apple Inc. | Stylus device |
CN103094295B (en) | 2013-01-23 | 2016-05-25 | 北京京东方光电科技有限公司 | Flat panel detector and preparation method thereof, camera head |
US10048775B2 (en) | 2013-03-14 | 2018-08-14 | Apple Inc. | Stylus detection and demodulation |
US10845901B2 (en) | 2013-07-31 | 2020-11-24 | Apple Inc. | Touch controller architecture |
US10061449B2 (en) | 2014-12-04 | 2018-08-28 | Apple Inc. | Coarse scan and targeted active mode scan for touch and stylus |
EP3244800A1 (en) | 2015-01-12 | 2017-11-22 | Real Time Imaging Technologies, LLC | Low-dose x-ray imaging system |
US10474277B2 (en) | 2016-05-31 | 2019-11-12 | Apple Inc. | Position-based stylus communication |
Citations (3)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
EP0365294A2 (en) * | 1988-10-18 | 1990-04-25 | Nikon Corporation | Photometric apparatus employing solid-state imaging device |
US5150393A (en) * | 1990-09-29 | 1992-09-22 | Siemens Aktiengesellschaft | X-ray diagnostics installation for mammography |
US5396072A (en) * | 1992-08-17 | 1995-03-07 | U. S. Philips Corporation | X-ray image detector |
Family Cites Families (2)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JPS5940581A (en) * | 1982-08-30 | 1984-03-06 | Seiko Epson Corp | Semiconductor device for display panel |
US5355013A (en) * | 1988-05-25 | 1994-10-11 | University Of Hawaii | Integrated radiation pixel detector with PIN diode array |
-
1995
- 1995-04-28 WO PCT/CA1995/000247 patent/WO1996034416A1/en active IP Right Grant
- 1995-04-28 JP JP53205096A patent/JP4063870B2/en not_active Expired - Lifetime
- 1995-04-28 DE DE69511292T patent/DE69511292T2/en not_active Expired - Fee Related
- 1995-04-28 US US08/952,325 patent/US5962856A/en not_active Expired - Lifetime
- 1995-04-28 EP EP95916537A patent/EP0823132B1/en not_active Expired - Lifetime
Patent Citations (3)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
EP0365294A2 (en) * | 1988-10-18 | 1990-04-25 | Nikon Corporation | Photometric apparatus employing solid-state imaging device |
US5150393A (en) * | 1990-09-29 | 1992-09-22 | Siemens Aktiengesellschaft | X-ray diagnostics installation for mammography |
US5396072A (en) * | 1992-08-17 | 1995-03-07 | U. S. Philips Corporation | X-ray image detector |
Non-Patent Citations (1)
Title |
---|
PATENT ABSTRACTS OF JAPAN vol. 8, no. 131 (E - 251) 19 June 1984 (1984-06-19) * |
Cited By (18)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US6239439B1 (en) | 1997-11-28 | 2001-05-29 | Canon Kabushiki Kaisha | Radiation detecting device and radiation detecting method |
EP0967655A3 (en) * | 1998-06-26 | 2000-06-28 | FTNI Inc. | Indirect x-ray image detector for radiology |
DE19833919A1 (en) * | 1998-07-28 | 2000-02-10 | Siemens Ag | High-efficiency, photoconductor-based, circular-array X-ray detector, avoids inefficiencies associated with scintillation detectors, to form compact unit suitable for use in medical tomography or transport security |
JP2000065933A (en) * | 1998-08-26 | 2000-03-03 | Fuji Photo Film Co Ltd | Radiation image detecting apparatus |
US6667481B2 (en) | 2000-03-09 | 2003-12-23 | Sharp Kabushiki Kaisha | Two-dimensional image sensor |
US7122804B2 (en) | 2002-02-15 | 2006-10-17 | Varian Medical Systems Technologies, Inc. | X-ray imaging device |
EP1616434A1 (en) * | 2003-04-22 | 2006-01-18 | Canon Kabushiki Kaisha | Photoelectric conversion device and radiation photography apparatus |
WO2004095833A1 (en) | 2003-04-22 | 2004-11-04 | Canon Kabushiki Kaisha | Photoelectric conversion device and radiation photography apparatus |
EP1616434A4 (en) * | 2003-04-22 | 2009-10-28 | Canon Kk | Photoelectric conversion device and radiation photography apparatus |
US7791032B2 (en) | 2003-08-12 | 2010-09-07 | Simon Fraser University | Multi-mode digital imaging apparatus and system |
EP1813096A1 (en) * | 2004-10-20 | 2007-08-01 | Simon Fraser University | High gain digital imaging system |
EP1813096A4 (en) * | 2004-10-20 | 2008-08-20 | Univ Fraser Simon | High gain digital imaging system |
US7995113B2 (en) | 2004-10-20 | 2011-08-09 | Simon Fraser University | High gain digital imaging system |
WO2007017470A1 (en) * | 2005-08-08 | 2007-02-15 | Siemens Aktiengesellschaft | Flat screen detector |
US7775712B1 (en) * | 2006-06-13 | 2010-08-17 | Virtual Imaging, Inc. | Modified grid cabinet assembly |
US8199236B2 (en) | 2007-09-11 | 2012-06-12 | Simon Fraser University/Industry Liason Office | Device and pixel architecture for high resolution digital |
US9364191B2 (en) | 2013-02-11 | 2016-06-14 | University Of Rochester | Method and apparatus of spectral differential phase-contrast cone-beam CT and hybrid cone-beam CT |
US10478142B2 (en) | 2013-02-11 | 2019-11-19 | University Of Rochester | Method and apparatus of spectral differential phase-contrast cone-beam CT and hybrid cone-beam CT |
Also Published As
Publication number | Publication date |
---|---|
EP0823132A1 (en) | 1998-02-11 |
JP4063870B2 (en) | 2008-03-19 |
DE69511292D1 (en) | 1999-09-09 |
US5962856A (en) | 1999-10-05 |
EP0823132B1 (en) | 1999-08-04 |
JPH11504163A (en) | 1999-04-06 |
DE69511292T2 (en) | 1999-12-02 |
Similar Documents
Publication | Publication Date | Title |
---|---|---|
US5962856A (en) | Active matrix X-ray imaging array | |
Kasap et al. | Direct-conversion flat-panel X-ray image sensors for digital radiography | |
Kasap et al. | Direct-conversion flat-panel X-ray image detectors | |
Zhao et al. | X‐ray imaging using amorphous selenium: Feasibility of a flat panel self‐scanned detector for digital radiology | |
Lee et al. | New digital detector for projection radiography | |
Antonuk et al. | Strategies to improve the signal and noise performance of active matrix, flat‐panel imagers for diagnostic x‐ray applications | |
Yaffe et al. | X-ray detectors for digital radiography | |
EP0830619B1 (en) | X-ray image sensor | |
Zhao et al. | Digital radiology using active matrix readout of amorphous selenium: Construction and evaluation of a prototype real‐time detector | |
US7323692B2 (en) | Flat-panel detector with avalanche gain | |
Zhao et al. | Large-area solid state detector for radiology using amorphous selenium | |
Antonuk et al. | Large-area 97-um pitch indirect-detection active-matrix flat-panel imager (AMFPI) | |
JPH04214669A (en) | Solid-state radiation detector | |
JP2000513443A (en) | Imaging device | |
CN102364357A (en) | Dual screen radiographic detector with improved spatial sampling | |
US6229877B1 (en) | Radiation image recording and read-out method and apparatus | |
EP1207559A2 (en) | Radiation detecting apparatus, methods of producing apparatus, and radiographic imaging system | |
KR20160047314A (en) | Apparatus and method for detecting radiation | |
Pang et al. | Digital radiology using active matrix readout of amorphous selenium: Geometrical and effective fill factors | |
US20030010942A1 (en) | Image detector and fabricating method of the same, image recording method and retrieving method, and image recording apparatus and retrieving apparatus | |
André et al. | Integrated CMOS-selenium x-ray detector for digital mammography | |
Street et al. | Amorphous silicon arrays develop a medical image | |
Rowlands et al. | Direct-conversion flat-panel x-ray imaging: reduction of noise by presampling filtration | |
US6501089B1 (en) | Image detector, fabrication method thereof, image recording method, image recorder, image reading method, and image reader | |
Rowlands | Current advances and future trends in X-ray digital detectors for medical applications |
Legal Events
Date | Code | Title | Description |
---|---|---|---|
AK | Designated states |
Kind code of ref document: A1 Designated state(s): CA JP US |
|
AL | Designated countries for regional patents |
Kind code of ref document: A1 Designated state(s): AT BE CH DE DK ES FR GB GR IE IT LU MC NL PT SE |
|
DFPE | Request for preliminary examination filed prior to expiration of 19th month from priority date (pct application filed before 20040101) | ||
121 | Ep: the epo has been informed by wipo that ep was designated in this application | ||
ENP | Entry into the national phase |
Ref document number: 2218059 Country of ref document: CA Kind code of ref document: A Ref document number: 2218059 Country of ref document: CA |
|
WWE | Wipo information: entry into national phase |
Ref document number: 1995916537 Country of ref document: EP |
|
ENP | Entry into the national phase |
Ref document number: 1996 532050 Country of ref document: JP Kind code of ref document: A |
|
WWP | Wipo information: published in national office |
Ref document number: 1995916537 Country of ref document: EP |
|
WWE | Wipo information: entry into national phase |
Ref document number: 08952325 Country of ref document: US |
|
WWG | Wipo information: grant in national office |
Ref document number: 1995916537 Country of ref document: EP |