Flat panel detector and manufacturing method

Abstract

A flat panel detector and a manufacturing method. The flat panel detector comprises a first substrate and a second substrate. The first substrate comprises a driving circuit, the second substrate comprises a photosensitive element, the first substrate and the second substrate are arranged opposite to each other to form a box, and the driving circuit is electrically connected to the photosensitive element to drive the photosensitive element. The flat panel detector can not only improve the filling rate of the photodiode in the pixel unit and expand the photosensitive area of ​​the pixel unit in the flat panel detector, but also effectively prevent static electricity and scratches generated during use, and improve the photoelectric characteristics and yield of the flat panel detector.

Description

Technical Field

[0001] Embodiments of the present disclosure relate to a flat panel detector and a manufacturing method thereof. Background Art

[0002] In recent years, X-ray detection has been widely used in various fields such as medical treatment, safety, non-destructive testing and scientific research. At present, the more common X-ray detection technology is the X-ray digital radiography (Digital Radiography, DR) detection technology that appeared in the late 1990s. Flat panel detectors (Flat Panel Detector, FPD) are used in X-ray digital photography detection technology, and its pixel size can be less than 0.1mm, so its imaging quality and resolution are almost comparable to those of film photography systems. At the same time, it also overcomes the shortcomings of film photography systems and provides convenience for computer processing of images. Summary of the invention

[0003] At least one embodiment of the present disclosure provides a flat panel detector, comprising a first substrate and a second substrate, wherein the first substrate comprises a driving circuit, the second substrate comprises a photosensitive element, the first substrate and the second substrate are arranged opposite to each other to form a box, and the driving circuit is electrically connected to the photosensitive element to drive the photosensitive element.

[0004] For example, the flat panel detector provided by an embodiment of the present disclosure further includes a conductive adhesive, wherein the conductive adhesive is disposed between the first substrate and the second substrate to bond the two substrates together.

[0005] For example, in the flat panel detector provided in an embodiment of the present disclosure, the driving circuit and the photosensitive element at least partially overlap in the direction in which the first substrate and the second substrate face each other.

[0006] For example, in a flat panel detector provided in an embodiment of the present disclosure, the first substrate further includes a light shielding layer. The light shielding layer covers directly above the driving circuit, so as to be closer to the second substrate than the driving circuit.

[0007] For example, in a flat panel detector provided in an embodiment of the present disclosure, the first substrate further includes a conductive connection portion. The conductive connection portion is electrically connected to the driving circuit, is disposed on a surface of the first substrate, and is electrically connected to the photosensitive element.

[0008] For example, in the flat panel detector provided in an embodiment of the present disclosure, the conductive connection portion includes a metal electrode, a conductive glue or a conductive spacer.

[0009] For example, in a flat panel detector provided in an embodiment of the present disclosure, the first substrate further includes a first passivation layer. The first passivation layer is disposed between the conductive connection portion and the driving circuit, and the first passivation layer includes an opening region, and the conductive connection portion is disposed in the opening region.

[0010] For example, in a flat panel detector provided in an embodiment of the present disclosure, the first passivation layer is a planarization layer, so that the first substrate has a substantially flat surface.

[0011] For example, in a flat panel detector provided in an embodiment of the present disclosure, the second substrate further includes a substrate and a transparent electrode layer formed on the substrate, and the photosensitive element is arranged on a side of the transparent electrode layer away from the substrate and is electrically connected thereto.

[0012] For example, in a flat panel detector provided in an embodiment of the present disclosure, the first substrate includes a first substrate, the second substrate includes a second substrate, and the first substrate and the second substrate are glass or plastic.

[0013] For example, in a flat panel detector provided in an embodiment of the present disclosure, the photosensitive element includes a photodiode, and the photodiode is a PIN-type photodiode.

[0014] For example, in a flat panel detector provided in an embodiment of the present disclosure, the P-type layer, the I-type layer and the N-type layer of the PIN-type photodiode are stacked in sequence in a direction opposite to the first substrate and the second substrate.

[0015] For example, the flat panel detector provided in one embodiment of the present disclosure further includes a scanning circuit. The scanning circuit is connected to the driving circuit and is configured to provide a scanning signal to control the driving circuit.

[0016] For example, the flat panel detector provided in an embodiment of the present disclosure further includes a voltage reading circuit. The voltage reading circuit is connected to the driving circuit and is configured to read the voltage signal generated by the photosensitive element through the driving circuit.

[0017] At least one embodiment of the present disclosure further provides a method for manufacturing a flat panel detector, comprising: forming a first substrate including a driving circuit; forming a second substrate including a photosensitive element; and arranging the first substrate and the second substrate relative to each other to align the driving circuit and the photosensitive element so that the driving circuit and the photosensitive element are electrically connected.

[0018] For example, a manufacturing method provided by an embodiment of the present disclosure further includes: providing a conductive adhesive between the first substrate and the second substrate to bond the two together.

[0019] For example, a manufacturing method provided by an embodiment of the present disclosure further includes: covering a light-shielding layer directly above the driving circuit, and after the first substrate and the second substrate are relatively arranged to be box-matched, making the light-shielding layer closer to the second substrate relative to the driving circuit.

[0020] For example, a manufacturing method provided by an embodiment of the present disclosure further includes: forming a first passivation layer including an opening area on the driving circuit; and forming a conductive connection portion in the opening area to connect the driving circuit and the photosensitive element.

[0021] For example, in a manufacturing method provided in an embodiment of the present disclosure, forming a second substrate including the photosensitive element includes: forming a transparent electrode layer on a substrate of the second substrate, and then forming the photosensitive element on the transparent electrode layer. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] In order to more clearly illustrate the technical solutions of the embodiments of the present disclosure, the drawings of the embodiments will be briefly introduced below. Obviously, the drawings in the following description only relate to some embodiments of the present disclosure, but are not intended to limit the present disclosure.

[0023] Figure 1A is a circuit diagram of a flat panel detector;

[0024] Figure 1B is a schematic diagram of the structure of a flat panel detector;

[0025] Figure 2 A schematic diagram of the structure of a flat panel detector provided in some embodiments of the present disclosure;

[0026] Figure 3 A schematic diagram of the structure of another flat panel detector provided in some embodiments of the present disclosure;

[0027] Figure 4 A schematic structural diagram of a first substrate in a flat panel detector provided in some embodiments of the present disclosure;

[0028] Figure 5 A schematic diagram of the structure of a second substrate in a flat panel detector provided in some embodiments of the present disclosure; and

[0029] Figure 6 A flow chart of a method for manufacturing a flat panel detector provided in some embodiments of the present disclosure. DETAILED DESCRIPTION

[0030] In order to make the purpose, technical solution and advantages of the embodiments of the present disclosure clearer, the technical solution of the embodiments of the present disclosure will be clearly and completely described below in conjunction with the drawings of the embodiments of the present disclosure. Obviously, the described embodiments are part of the embodiments of the present disclosure, not all of the embodiments. Based on the described embodiments of the present disclosure, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present disclosure.

[0031] Unless otherwise defined, the technical terms or scientific terms used in the present disclosure should be understood by people with ordinary skills in the field to which the present disclosure belongs. The "first", "second" and similar words used in the present disclosure do not indicate any order, quantity or importance, but are only used to distinguish different components. Similarly, similar words such as "one", "one" or "the" do not indicate quantity restrictions, but indicate that there is at least one. Similar words such as "include" or "comprise" mean that the elements or objects appearing before the word cover the elements or objects listed after the word and their equivalents, without excluding other elements or objects. Similar words such as "connect" or "connected" are not limited to physical or mechanical connections, but can include electrical connections, whether direct or indirect. "Up", "down", "left", "right" and the like are only used to indicate relative positional relationships. When the absolute position of the described object changes, the relative positional relationship may also change accordingly.

[0032] The present disclosure is described below through several specific embodiments. In order to keep the following description of the embodiments of the present disclosure clear and concise, detailed descriptions of known functions and known components may be omitted. When any component of the embodiments of the present disclosure appears in more than one figure, the component is represented by the same reference numeral in each figure.

[0033] According to the different modes of photoelectron conversion involved in imaging, digital X-ray flat-panel detectors can be divided into two types: direct conversion type (Direct DR) and indirect conversion type (Indirect DR). Figure 1A Figure 2 shows a schematic diagram of the circuit of an indirect conversion flat panel detector. Figure 1AAs shown, the indirect conversion type X-ray flat panel detector includes a gate drive circuit 10, a signal amplification and reading circuit 101, and a plurality of pixel units 12 arranged in an array. For example, in one example, each of the plurality of pixel units 12 includes a thin film transistor 104, a photodiode 106, a storage capacitor, and an X-ray conversion layer (not shown in the figure) formed by a scintillator (cesium iodide) or a phosphor (gadolinium oxysulfide). For example, the storage capacitor can be provided separately, or it can be formed by electrodes located on the upper and lower sides of the photodiode 106 (for example, a transparent electrode and the second electrode of the thin film transistor T, which will be described in detail later), that is, a reverse biased photodiode capacitor is formed. For example, in another example, the pixel unit may also include a reset transistor and a switch transistor (not shown in the figure), which are connected to the above-mentioned thin film transistor 104 and the photodiode 106. For example, the reset transistor is controlled by the reset signal to work in a switching state, and when it is turned on, the voltage of the gate of the switching transistor is controlled to be at a cut-off voltage; the switching transistor is a source follower, working in a linear state, for example, its gate is also connected to one end of the photodiode, so that its source output voltage follows the voltage change on the photodiode, and its gain is slightly less than 1; the thin film transistor 104 still acts as an output transistor, and controls the output of the source voltage of the switching transistor under the control of the gate scanning signal. For example, the gate drive circuit 10 is connected to N rows of pixel units 12 through N gate lines, respectively, and the signal amplification and reading circuit 101 is connected to M columns of pixel units 12 through M data lines, respectively, and the N rows of pixel units 12 are also connected to N bias lines 105, respectively, to receive bias. Figure 1A As shown, Gn represents the gate line connected to the pixel unit in the nth row, Gn+1 represents the gate line connected to the pixel unit in the n+1th row, Dm-1 represents the data line connected to the pixel unit in the m-1th column, Dm represents the data line connected to the pixel unit in the mth column, and Dm+1 represents the data line connected to the pixel unit in the m+1th column.

[0034] For example, the photodiode 106 works under the bias voltage (reverse voltage) provided by the bias line 105. When the X-ray irradiates the array substrate, the X-ray conversion layer converts the X-ray into visible light (for example, light with a wavelength range of 350nm-770nm). When the visible light irradiates the photodiode, the photodiode 106 converts the visible light into an electrical signal, for example, and the electrical signal is stored by the storage capacitor. Then, under the action of the gate scanning signal provided row by row by the gate drive circuit 10, the thin film transistor 104 is turned on row by row, and the charge converted by the photodiode 106 is transmitted to the signal amplification and reading circuit 101 through the data line. The signal amplification and reading circuit 101 further amplifies the electrical signal, performs analog / digital conversion and other processing to obtain a digital signal, and transmits the digital signal to the image processing system of the computer (for example, CPU or GPU, etc.) to form an X-ray image.

[0035] Figure 1B Figure 1 is a schematic diagram of the structure of a flat panel detector. Figure 1B As shown, the flat panel detector includes a substrate 11 and a thin film transistor T, a photodiode 15, a transparent electrode 16, a bias line 19, a passivation layer 20, a protective layer 21, etc. formed on the substrate 11. The manufacturing method of the flat panel detector includes the following steps.

[0036] First, a gate electrode 121 of a thin film transistor T is formed on a base substrate 11; a gate insulating layer 122 and an active layer 13 are sequentially formed on the gate electrode 121; a first electrode (e.g., source electrode) 141 and a second electrode (e.g., drain electrode) 142 of the thin film transistor T are formed on the active layer 13. For example, the gate electrode 121 of the thin film transistor T is connected to the gate driving circuit 10 through a gate line to receive a gate scanning signal (refer to Figure 1A ), the second electrode 142 of the thin film transistor is connected to the photodiode 15 (to be formed in the following step) through a via hole on the first passivation layer 123, and the first electrode 141 of the thin film transistor is connected to the signal amplification and reading circuit 101 through a data line (reference Figure 1A ) to read the electrical signal generated by the photodiode 15 when the thin film transistor T is turned on under the control of the gate scanning signal.

[0037] It should be noted that the material of the active layer 13 may include oxide semiconductors, organic semiconductors, amorphous silicon, or polycrystalline silicon. For example, oxide semiconductors include metal oxide semiconductors (such as indium gallium zinc oxide (IGZO)), and polycrystalline silicon includes low-temperature polycrystalline silicon or high-temperature polycrystalline silicon.

[0038] For example, the material of the gate insulating layer 122 may include an inorganic insulating material such as SiNx, SiOx, SiNxOy, etc., an organic insulating material such as an organic resin, etc., or other suitable materials.

[0039] Next, a first passivation layer 123 is formed on the first electrode 141 and the second electrode 142 of the thin film transistor T, and a photodiode 15 is formed on the first passivation layer 123, and a continuously arranged transparent electrode layer 16 is formed on the photodiode 15. For example, the first passivation layer 123 includes an opening area (i.e., a via hole), and the photodiode 15 is connected to the second electrode 142 of the thin film transistor T through the opening area, so as to transmit the electrical signal generated by the photodiode 15 to the signal amplification and reading circuit 101 through the second electrode 142.

[0040] For example, a buffer insulating layer 17 and a second passivation layer 18 are formed on the transparent electrode layer 16, and a bias line 19 is formed on the second passivation layer 18. The bias line 19 is electrically connected to the bias end, and the bias line 19 is connected to the transparent electrode layer 16 through vias on the buffer insulating layer 17 and the second passivation layer 18, thereby providing a negative bias for the transparent electrode layer 16, so that the photodiode is in an operating state.

[0041] Finally, a third passivation layer 20 is formed on the bias line 19, and a 1 μm thick silicon nitride or 1-2 μm thick organic resin is formed on the third passivation layer 20 as a protective layer 21 of the photodiode. Alternatively, the protective layer 21 may also be a multi-layer composite protective film including an inorganic layer and an organic layer.

[0042] For example, the materials of the first passivation layer 123, the buffer insulating layer 17, the second passivation layer 18 and the third passivation layer 20 can be consistent with the material of the gate insulating layer 122, such as inorganic insulating materials such as SiNx, SiOx, SiNxOy, organic insulating materials such as organic resins, or other suitable materials.

[0043] It can be seen from the above steps that the photodiode and the thin film transistor are formed on the same substrate 11. If a flat-panel detector with this structure is used, when the size of the pixel unit is 140μm, the filling rate of the pixel unit, that is, the photosensitive area of ​​the pixel unit of the flat-panel detector is generally about 60% of the total area of ​​the pixel unit, which results in a low effective photosensitive area of ​​the flat-panel detector. Therefore, when using the same dose of X-rays, the sensitivity of the flat-panel detector to acquire images is low, which will affect the diagnosis of subtle tissue structures in medical applications. In particular, as the resolution of the flat-panel detector increases, the size of a single pixel unit is reduced from 140μm to 75μm. At this time, the filling rate of the pixel unit is only about 40%, which seriously restricts its application in the field of fine diagnosis (such as dentistry, breast and other fields).

[0044] In addition, a protective layer of about 1 μm silicon nitride or 1 to 2 μm organic resin is provided on the surface of the photodiode, which makes the flat-panel detector less resistant to external static electricity and scratches. Static electricity or scratches are prone to occur during detection and bonding of the flat-panel detector to the scintillator, which can easily cause the photodiode to fail.

[0045] An embodiment of the present disclosure provides a flat panel detector, including a first substrate and a second substrate. The first substrate includes a driving circuit, the second substrate includes a photosensitive element, the first substrate and the second substrate are arranged opposite to each other to form a box, and the driving circuit is electrically connected to the photosensitive element to drive the photosensitive element. At least one embodiment of the present disclosure also provides a manufacturing method corresponding to the flat panel detector.

[0046] For the flat-panel detector provided by the above-mentioned embodiment of the present disclosure, on the one hand, the manufacturing process of the flat-panel detector is relatively simple, and it is formed by two layers of substrates arranged opposite to each other. In this structure, the photosensitive element can be arranged as a whole layer on one of the substrates, so that the filling rate of the photosensitive element in the pixel unit (that is, the photosensitive area) can be effectively improved, and the photosensitivity of the flat-panel detector can be improved, so that it can be applied to the field of precision diagnosis, etc.; on the other hand, the upper and lower surfaces of the flat-panel detector are both substrate materials, so in the process of using it for detection or bonding it with a scintillator, static electricity and scratches can be effectively prevented, thereby improving the photoelectric characteristics and yield of the flat-panel detector.

[0047] The embodiments of the present disclosure and some examples thereof are described in detail below with reference to the accompanying drawings.

[0048] Figure 2 This is a schematic diagram of the structure of a flat panel detector provided by an embodiment of the present disclosure. For example, the flat panel detector can be used to form X-ray images in the field of fine diagnosis and has good photosensitivity.

[0049] In one example, if Figure 2As shown, the flat panel detector 100 includes a first substrate 111 and a second substrate 121. The first substrate 111 includes a driving circuit 112, and the second substrate 121 includes a photosensitive element 122. The first substrate 111 and the second substrate 121 are arranged relative to each other, for example, by a sealing glue 1150, so that the driving circuit 112 is electrically connected to the photosensitive element 122 to drive the photosensitive element 122. For example, the driving circuit 112 and the photosensitive element 122 at least partially overlap in the direction in which the first substrate 111 and the second substrate 121 face each other, so that the driving circuit 112 and the photosensitive element 122 are electrically connected. The sealing glue 1150 is applied around the periphery of the first substrate 111, or around the periphery of the second substrate 121; after the first substrate 111 and the second substrate 121 are sealed and bonded together, the sealing glue 1150 is cured by heating or light.

[0050] For example, the driving circuit 112 may include transistors, such as field effect transistors, thin film transistors, etc., and may also include storage capacitors, etc. as needed; the photosensitive element 122 may include a photodiode or other organic photosensitive materials. For example, the photodiode is a PN-type photodiode, a PIN-type photodiode, etc. For example, the material of the PIN-type photodiode is single crystal silicon, and its P-type layer, I-type layer and N-type layer are stacked in sequence in the direction relative to the second substrate 121 and the first substrate 111. For example, in the direction in which the second substrate 121 points to the first substrate 111, a P-type layer, an I-type layer and an N-type layer are sequentially formed on the second substrate 121, thereby forming a PIN photodiode on the second substrate 121.

[0051] For example, the first substrate 111 further includes a first substrate (not shown in the figure), the second substrate 121 further includes a second substrate (not shown in the figure), and the driving circuit 112 is disposed on the first substrate, and the photosensitive element 122 is disposed on the second substrate. The following embodiments are the same and will not be described in detail. For example, the first substrate and the second substrate may be made of glass, plastic, quartz or other suitable materials, and the embodiments of the present disclosure are not limited to this.

[0052] For example, the driving circuit 112 can be obtained by using a conventional semiconductor manufacturing process. Below, the manufacturing method when the driving circuit 112 is a thin film transistor is introduced as an example. For example, first, a gate electrode 1121 of the thin film transistor 112 is formed on the first substrate 111; a gate insulating layer 1130 and an active layer 1124 are sequentially formed on the gate electrode 1121; and a first electrode (for example, a source electrode) 1122 and a second electrode (for example, a drain electrode) 1123 of the thin film transistor 112 are formed on the active layer 1124. For example, in this example, the gate electrode 1121 of the thin film transistor 112 is connected to the gate electrode 1121 through a gate line. Figure 1AThe gate drive circuit 10 shown in FIG. 1 is connected to receive the gate scanning signal, the second electrode 1123 of the thin film transistor 112 is connected to the photosensitive element 122 through the via hole of the first passivation layer 1131 (which will be described in detail below), and the first electrode 1122 of the thin film transistor 112 is connected to the photosensitive element 122 through the data line. Figure 1A The signal amplification and reading circuit 101 shown in the figure is connected to read the electrical signal generated by the photosensitive element 122 when the thin film transistor 112 is turned on under the control of the gate scanning signal, and convert it into a digital signal to be transmitted to the image processing unit (for example, CPU, GPU, etc.) to form an X-ray image.

[0053] For example, the materials used for the first electrode 1122 , the second electrode 1123 and the gate 1121 of the thin film transistor 112 may include aluminum, aluminum alloy, copper, copper alloy or any other suitable material, which is not limited in the embodiments of the present disclosure.

[0054] It should be noted that the material of the active layer 124 may include oxide semiconductors, organic semiconductors or amorphous silicon, polycrystalline silicon, etc. For example, the oxide semiconductor includes a metal oxide semiconductor (such as indium gallium zinc oxide (IGZO)), and the polycrystalline silicon includes low-temperature polycrystalline silicon or high-temperature polycrystalline silicon, etc. The embodiments of the present disclosure are not limited to this.

[0055] For example, the material of the gate insulating layer 1130 may include inorganic insulating materials such as SiNx, SiOx, SiNxOy, etc., organic insulating materials such as organic resin, etc., or other suitable materials, which is not limited in the embodiments of the present disclosure.

[0056] For example, the first substrate 111 further includes a first passivation layer 1131, which can be used as a planarization layer to make the first substrate 111 have a substantially flat surface. For example, the second electrode 1123 of the thin film transistor 112 can be electrically connected to the photosensitive element 122 included in the second substrate 121 through a via hole in the first passivation layer 1131. It should be noted that the material of the first passivation layer 1131 can be the same material as the gate insulating layer 1130, which will not be repeated here.

[0057] For example, the photosensitive element 122 can be disposed on the second substrate 121 as a whole layer, thereby increasing the filling rate of the photodiode in the pixel unit, that is, the photosensitive area of ​​the flat panel detector, improving the photosensitive performance of the flat panel detector, and facilitating its application in the field of fine diagnosis. Moreover, the flat panel detector 100 is provided with two layers of substrates (i.e., the first substrate 111 and the second substrate 121) disposed opposite to each other, and the two are bonded together by the frame sealant 1150 to form a box, so the manufacturing process is relatively simple.

[0058] In addition, the upper and lower surfaces of the flat-panel detector are both made of substrate material, so when using it for detection or bonding it to a scintillator, static electricity and scratches can be effectively prevented, thereby improving the photoelectric properties and yield of the flat-panel detector.

[0059] In another example, for example, in Figure 2 On the basis of the example shown, the flat panel detector further includes a conductive glue (not shown in the figure). For example, the conductive glue is disposed between the first substrate 111 and the second substrate 121 to further bond the two together. For example, in this example, the conductive glue can be disposed between the first passivation layer 1131 and the photosensitive element 122 to bond the first passivation layer 1131 and the photosensitive element 122 together, that is, to bond the first substrate 111 and the second substrate 121 together. For example, the conductive glue can also be directly coated on the photosensitive element 122. For example, when the photosensitive element is implemented as a PIN-type photodiode, that is, the photosensitive element 122 includes a P-type layer, an I-type layer, an N-type layer and a conductive glue in sequence, and the embodiments of the present disclosure are not limited to this.

[0060] For example, the conductive adhesive includes a matrix resin and a conductive filler, i.e., conductive particles. The conductive particles are combined together by the bonding effect of the matrix resin to form a conductive path, thereby realizing the conductive connection of the bonded materials (e.g., the driving circuit and the photosensitive element). The conductive adhesive is divided into isotropic conductive adhesive and anisotropic conductive adhesive according to the conductive direction. For example, the flat panel detector 100 may use an anisotropic conductive adhesive (ACA), which is conductive in one direction, such as the Z direction (i.e., the direction in which the conductive adhesive is squeezed), but not conductive in the X and Y directions (perpendicular to the squeezing direction), i.e., the ACA is conductive in the direction relative to the second substrate 121 and the first substrate 11, but not conductive in the direction perpendicular to the relative direction, so that while the first substrate 111 and the second substrate 121 are bonded and fixed, the electrical connection characteristics of the driving circuit 112 and the photosensitive element 122 are ensured to remain unchanged.

[0061] Figure 3 This is a schematic diagram of the structure of another flat panel detector provided by an embodiment of the present disclosure. Figure 3 As shown, the flat panel detector is Figure 2 The structure of the flat panel detector shown in is similar to that of the flat panel detector shown in FIG. 1 , except that: the first substrate 111 further includes a light shielding layer 1141 and / or a conductive connecting portion 1142; in addition, the second substrate 121 further includes a transparent electrode layer 123. It should be noted that for the sake of clarity and simplicity, similar parts of the flat panel detector can be referred to. Figure 2 The relevant description in will not be repeated here.

[0062] For example, the transparent electrode layer 123 is used as the top electrode of the photosensitive element 122, and the second electrode 1123 of the thin film transistor 112 connected to the photosensitive element 122 through the conductive connection portion 1142 is used as the bottom electrode of the photosensitive element 122. Figure 1A , and receives a constant voltage (e.g., -6V) provided by the bias line 105. For example, when the bias line 105 provides a negative bias to the top electrode, the photosensitive element 122 is turned on, and when irradiated with visible light (e.g., the visible light can be obtained by converting X-rays by the X-ray conversion layer), the light signal is converted into an electrical signal, which can be stored in a storage capacitor (not shown). When reading the signal, the gate drive circuit 10 provides a gate-to-scan signal to the pixel unit row by row to turn on the thin film transistor 112 of the pixel unit row by row, so that the electrical signal generated by the photosensitive element 122 is transmitted to the second electrode 1123 of the thin film transistor 112 through the conductive connection portion 1142, and the electrical signal received by the second electrode 1123 is transmitted to the signal amplification and reading circuit 101 through the first electrode 1122 of the turned-on thin film transistor 112 for subsequent processing, and the processed electrical signal is used to form an image.

[0063] Figure 4 for Figure 3 The structural diagram of the first substrate 112 of the flat panel detector is shown in FIG. Figure 4 As shown, in Figure 2 On the basis of the example shown, the first substrate 111 further includes: a light shielding layer 1141 and a conductive connecting portion 1142 are formed on the first passivation layer 1131 .

[0064] For example, the light shielding layer 1141 covers the driving circuit 112, so that it is closer to the second substrate 121, that is, closer to the photosensitive element 122. For example, the light shielding layer 1141 may include an opaque material such as a metal electrode or a dark resin, so as to shield the driving circuit 112 from light and prevent the transmitted visible light from affecting the performance of the driving circuit 112.

[0065] For example, the conductive connection part 1142 is electrically connected to the driving circuit 112, is disposed on the surface of the first substrate 111 and is electrically connected to the photosensitive element 122. For example, the first passivation layer 1131 includes an opening area (including a via), and the conductive connection part 1142 is disposed in the opening area. For example, in the case where the light shielding layer is a material such as a metal electrode, the conductive connection part 1142 can be the same material as the light shielding layer 1141; of course, in the case where the flat panel detector includes a conductive glue, the conductive connection part 1142 can also be a conductive glue or a conductive spacer, or other conductive materials, so that the second electrode 1123 of the thin film transistor 112 can be connected to the photosensitive element 122 through the conductive connection part 1142, thereby realizing the transmission of electrical signals. The conductive connection part 1142 can also be a part of the second electrode 1123 of the thin film transistor 112, for example, connected to the photosensitive element 122 through the opening area of ​​the first passivation layer 1131, and the embodiments of the present disclosure are not limited to this.

[0066] For example, a third passivation layer (not shown) may be formed on the light shielding layer 1141. For example, the third passivation layer serves as a planarization layer so that the first substrate 111 has a substantially flat surface to be bonded to the photosensitive element 122 in the second substrate 121 through a conductive adhesive.

[0067] Figure 5 for Figure 3 The structural diagram of the second substrate 121 of the flat panel detector is shown in FIG. Figure 5 As shown, in Figure 2 Based on the example shown, the second substrate 121 further includes: forming a transparent electrode layer 123 on the substrate of the second substrate, and then forming a photosensitive element 122 on the transparent electrode layer 123. For example, the second substrate 121 further includes a substrate (not shown in the figure), the transparent electrode layer 123 is formed on the substrate, and the photosensitive element 122 is arranged on a side of the transparent electrode layer 123 away from the substrate and is electrically connected thereto.

[0068] For example, the transparent electrode layer 123 may be made of a material including transparent metal oxides such as indium tin oxide (ITO) or indium zinc oxide (IZO).

[0069] For example, the second substrate 121 may also include a bias line (not shown in the figure), etc., which can be connected to the transparent electrode layer 123 through a via hole in the passivation layer set on the transparent electrode layer 123, thereby providing a constant negative bias voltage for the transparent electrode layer, so that the photosensitive element 122 is in a working state.

[0070] For example, Figure 2 and Figure 3 The flat panel detectors shown may also include a scanning circuit and a voltage reading circuit (neither of which are shown in the figures).

[0071] For example, the scanning circuit is connected to the driving circuit 112 and is configured to provide a scanning signal to control the driving circuit 112. For example, the scanning circuit can be implemented as Figure 1A The gate drive circuit 10 shown. It should be noted that the gate drive circuit 10 can be prepared as an integrated circuit chip or a GOA type gate drive circuit, the integrated circuit chip is electrically connected to the gate line by bonding, and the GOA type gate drive circuit can include a plurality of cascaded shift register units, the shift register unit can be, for example, a 4T1C or other conventional structure in the art, which will not be described here. For example, the thin film transistor constituting the gate drive circuit can be obtained by a unified semiconductor preparation process, and the specific preparation process can be referred to Figure 2 The preparation process of the driving circuit 112 in the flat panel detector is shown in FIG.

[0072] For example, the voltage reading circuit is connected to the driving circuit 112 and is configured to read the voltage signal generated by the photosensitive element 122 through the driving circuit 112. For example, the voltage reading circuit can be implemented as Figure 1A The signal amplification and reading circuit 101 shown in the figure can amplify, perform analog-to-digital conversion and other processing on the voltage signal it reads to obtain a digital signal, and send the digital signal to an image processing unit (eg, CPU, GPU, etc.) to form a corresponding image.

[0073] It should be noted that, for the sake of clarity and simplicity, the embodiments of the present disclosure do not provide all the components of the flat panel detector. To realize the function of the substrate of the flat panel detector, those skilled in the art may provide and set other structures not shown according to specific needs, and the embodiments of the present disclosure are not limited to this.

[0074] For the flat-panel detector provided by the above-mentioned embodiment of the present disclosure, on the one hand, the manufacturing process of the flat-panel detector is relatively simple, and it is formed by two layers of relatively arranged substrates in a box, and in this structure, the photosensitive element can be arranged as a whole layer on one of the substrates, so that the filling rate of the photosensitive element in the pixel unit (that is, the photosensitive area) can be effectively improved, and the photosensitivity of the flat-panel detector can be improved, so that it can be applied to the field of precision diagnosis, etc.; on the other hand, the upper and lower surfaces of the flat-panel detector are both substrate materials, so in the process of using it for detection or bonding it with a scintillator, it can effectively prevent static electricity and scratches, and improve the photoelectric characteristics and yield of the flat-panel detector.

[0075] An embodiment of the present disclosure also provides a method for manufacturing a flat panel detector. Figure 6 A flowchart of a method for manufacturing a flat panel detector is shown. For example, the manufacturing method can be used to implement the flat panel detector provided by any embodiment of the present disclosure. For example, Figure 2 The flat panel detector shown in Figure 3 The flat panel detector shown in Figure 6 As shown, the method for manufacturing the flat panel detector includes steps S110 to S130.

[0076] Step S110: forming a first substrate including a driving circuit.

[0077] Step S120: forming a second substrate including a photosensitive element.

[0078] Step S130: The first substrate and the second substrate are arranged opposite to each other to align the first substrate and the second substrate so that the driving circuit and the photosensitive element are electrically connected.

[0079] In step S110, for example, when the driving circuit 112 is implemented as a thin film transistor, its manufacturing method includes: first, forming a gate electrode 1121 of the thin film transistor 112 on the first substrate 111; sequentially forming a gate insulating layer 1130 and an active layer 1124 on the gate electrode 1121; forming a first electrode (for example, a source electrode) 1122 and a second electrode (for example, a drain electrode) 1123 of the thin film transistor 112 on the active layer 1124. The detailed description of step S110 can be referred to Figure 2 and Figure 3 The introduction of the first substrate 111 of the flat panel detector is not repeated here.

[0080] In step S120, for example, when the photosensitive element 122 is implemented as a PIN type photodiode, its manufacturing method includes: sequentially forming a P-type layer, an I-type layer, and an N-type layer of the photodiode on the second substrate. For example, the photosensitive element 122 can be formed as a whole layer on the second substrate 121, thereby increasing the filling rate of the photosensitive element 122, expanding the photosensitive area of ​​the flat panel detector, and improving the photosensitive performance of the flat panel detector. For example, the detailed description of step S120 can refer to Figure 2 and Figure 3 The introduction of the second substrate 121 of the flat panel detector is not repeated here.

[0081] In step S130, the first substrate 111 and the second substrate 121 are processed as follows. Figure 2 or Figure 3 The box pairing arrangement shown is, for example, using a sealing glue to join the two. For example, a first passivation layer 1131 is also formed on the first substrate 111 so that the first substrate 111 has a substantially flat surface. For example, the first passivation layer 1131 includes a via hole, and the second electrode 1123 of the thin film transistor 112 can be electrically connected to the photosensitive element 122 included in the second substrate 112 through the via hole in the first passivation layer 1131. For example, in step S130, the driving circuit 112 and the photosensitive element 122 can be arranged to at least partially overlap in the direction in which the first substrate 111 and the second substrate 122 are facing each other.

[0082] For example, in one example, step S130 further includes: providing a conductive adhesive between the first substrate 111 and the second substrate 121 to bond the two together. For example, in this example, the conductive adhesive can be provided between the first passivation layer 1131 and the photosensitive element 122 to further bond the first passivation layer 1131 and the photosensitive element 122 together, that is, to bond the first substrate 111 and the second substrate 121 together. For example, the conductive adhesive can refer to Figure 2 The detailed description in the other example shown will not be repeated here.

[0083] For example, in one example, step S110 further includes: covering the light shielding layer 1141 directly above the driving circuit 112, and after the first substrate 111 and the second substrate 121 are arranged relative to each other to align, the light shielding layer 1141 is closer to the second substrate 121 relative to the driving circuit 112. For example, the light shielding layer 1141 may include an opaque material such as a metal electrode and a dark resin, so as to shield the driving circuit 112 from light and prevent the transmitted visible light from affecting the performance of the driving circuit 112. For example, the light shielding layer 1141 may refer to Figure 4 The detailed introduction of the flat panel detector shown will not be repeated here.

[0084] For example, in one example, step S110 further includes: forming a first passivation layer 1131 including an opening area on the driving circuit 112, and forming a conductive connection portion 1142 in the opening area of ​​the first passivation layer 1131 to connect the driving circuit 112 and the photosensitive element 122. For example, in the case where the light shielding layer is a material such as a metal electrode, the conductive connection portion 1142 can be the same material as the light shielding layer 1141; of course, in the case where the flat panel detector includes a conductive glue, the conductive connection portion 1142 can also be a conductive glue or a conductive spacer, or other conductive materials, so that the second electrode 1123 of the thin film transistor 112 can be connected to the photosensitive element 122 through the conductive connection portion 1142, thereby realizing the transmission of electrical signals. The conductive connection portion 1142 can also be a part of the second electrode 1123 of the thin film transistor 112, for example, connected to the photosensitive element 122 through the opening area of ​​the first passivation layer 1131, and the embodiments of the present disclosure are not limited to this.

[0085] For example, in one example, step S120 may further include: forming a transparent electrode layer 123 on the substrate of the second substrate 121, and then forming a photosensitive element 122 on the transparent electrode layer 123. For example, the photosensitive element 122 is disposed on a side of the transparent electrode layer 123 away from the substrate and is electrically connected thereto. For example, the transparent electrode layer 123 may be made of a material including a transparent metal oxide such as indium tin oxide (ITO) or indium zinc oxide (IZO). For example, the transparent electrode layer 123 may be made of a material such as a transparent metal oxide such as indium tin oxide (ITO) or indium zinc oxide (IZO). Figure 5 The detailed introduction of the flat panel detector shown will not be repeated here.

[0086] For example, the method for manufacturing the flat panel detector further includes preparing structures such as a scanning circuit, a voltage reading circuit, and a bias line in the peripheral area of ​​the array substrate.

[0087] For example, a bias line is formed on the second substrate 121 so that the bias line is connected to the transparent electrode layer 123 through a via hole of the passivation layer provided on the transparent electrode layer 123, thereby providing a constant negative bias voltage for the transparent electrode layer, so that the photosensitive element 122 is in working state.

[0088] For example, the scanning circuit is connected to the driving circuit 112 and is configured to provide a scanning signal to control the driving circuit 112. For example, the scanning circuit can be implemented as Figure 1A The gate drive circuit 10 shown. It should be noted that the gate drive circuit 10 can be prepared as an integrated circuit chip or a GOA type gate drive circuit, the integrated circuit chip is electrically connected to the gate line by bonding, and the GOA type gate drive circuit can include a plurality of cascaded shift register units, the shift register unit can be, for example, a 4T1C or other conventional structure in the art, which will not be described here. For example, the thin film transistor constituting the gate drive circuit can be obtained by a unified semiconductor manufacturing process.

[0089] For example, the voltage reading circuit is connected to the driving circuit 112 and is configured to read the voltage signal generated by the photosensitive element 122 through the driving circuit 112. For example, the voltage reading circuit can be implemented as Figure 1A The signal amplification and reading circuit 101 shown in the figure can amplify, perform analog-to-digital conversion and other processing on the voltage signal it reads to obtain a digital signal, and send the digital signal to an image processing unit (such as a CPU, GPU, etc.) to form a corresponding image. For example, the signal amplification and reading circuit 101 can be implemented as an integrated circuit chip.

[0090] It should be noted that in the embodiments of the present disclosure, the process of the manufacturing method of the flat panel detector may include more or fewer operations, and these operations may be performed sequentially or in parallel. Although the process of the manufacturing method described above includes multiple operations that appear in a specific order, it should be clearly understood that the order of the multiple operations is not limited. The manufacturing method described above may be performed once or multiple times according to predetermined conditions.

[0091] The technical effects of the method for manufacturing the flat panel detector provided in the above embodiment may refer to the technical effects of the flat panel detector provided in the embodiment of the present disclosure, which will not be described in detail here.

[0092] There are a few points to note:

[0093] (1) The drawings of the embodiments of the present disclosure only relate to the structures related to the embodiments of the present disclosure, and other structures may refer to the general design.

[0094] (2) In the absence of conflict, the embodiments of the present disclosure and the features therein may be combined with each other to obtain new embodiments.

[0095] The above description is merely an exemplary embodiment of the present disclosure and is not intended to limit the protection scope of the present disclosure. The protection scope of the present disclosure is determined by the appended claims.

Claims

1. A flat panel detector, comprising a first substrate and a second substrate; wherein: The first substrate includes a driving circuit, The second substrate includes a photosensitive element, The first substrate and the second substrate are arranged opposite to each other to form a box, and the driving circuit is electrically connected to the photosensitive element to drive the photosensitive element; The driving circuit includes a transistor, a gate of the transistor is connected to a gate driving circuit to receive a gate scanning signal, a first electrode of the transistor is connected to a signal amplifying and reading circuit, and the transistor is configured to be turned on under the control of the scanning signal to transmit the signal generated by the photosensitive element to the signal amplifying and reading circuit; the transistor and the photosensitive element at least partially overlap in a direction in which the first substrate and the second substrate face each other; The first substrate further includes a light shielding layer and a conductive connection portion, wherein the light shielding layer covers directly above the driving circuit so as to be closer to the second substrate than the driving circuit, and the conductive connection portion is electrically connected to the driving circuit, is disposed on the surface of the first substrate and is electrically connected to the photosensitive element; Among them, one electrode among the source and the drain of the transistor which is connected to the photosensitive element through the conductive connecting portion serves as the bottom electrode of the photosensitive element.

2. The flat panel detector according to claim 1, further comprising a conductive adhesive, wherein: The conductive adhesive is disposed between the first substrate and the second substrate to bond the two substrates together.

3. The flat panel detector according to claim 1 or 2, wherein: The driving circuit and the photosensitive element at least partially overlap in a direction in which the first substrate and the second substrate face each other.

4. The flat panel detector according to claim 1, wherein: The conductive connection part includes a metal electrode, a conductive glue or a conductive spacer.

5. The flat panel detector according to claim 1, wherein: The first substrate further includes a first passivation layer, The first passivation layer is disposed between the conductive connection portion and the driving circuit. The first passivation layer includes an opening area, The conductive connection portion is disposed in the opening area.

6. The flat panel detector according to claim 5, wherein: The first passivation layer is a planarization layer so that the first substrate has a substantially planar surface.

7. The flat panel detector according to claim 1 or 2, wherein: The second substrate further includes a substrate and a transparent electrode layer formed on the substrate. The photosensitive element is arranged on a side of the transparent electrode layer away from the substrate and is electrically connected thereto.

8. The flat panel detector according to claim 1 or 2, wherein: The first substrate includes a first substrate, the second substrate includes a second substrate, and the first substrate and the second substrate are glass or plastic.

9. The flat panel detector according to claim 1 or 2, wherein: The photosensitive element includes a photodiode, The photodiode is a PIN type photodiode.

10. The flat panel detector according to claim 9, wherein: The P-type layer, the I-type layer and the N-type layer of the PIN-type photodiode are sequentially stacked in a direction in which the second substrate is opposite to the first substrate.

11. The flat panel detector according to claim 1, further comprising a scanning circuit, wherein: The scanning circuit is connected to the driving circuit and is configured to provide a scanning signal to control the driving circuit.

12. The flat panel detector according to claim 1, further comprising a voltage reading circuit, wherein: The voltage reading circuit is connected to the driving circuit and is configured to read the voltage signal generated by the photosensitive element through the driving circuit.

13. A method for manufacturing a flat panel detector, comprising: forming a first substrate including a driving circuit; forming a second substrate including a photosensitive element; The first substrate and the second substrate are arranged opposite to each other to form a box, so that the driving circuit and the photosensitive element are electrically connected; The driving circuit includes a transistor, a gate of the transistor is connected to a gate driving circuit to receive a gate scanning signal, a first electrode of the transistor is connected to a signal amplifying and reading circuit, and the transistor is configured to be turned on under the control of the scanning signal to transmit the signal generated by the photosensitive element to the signal amplifying and reading circuit; the transistor and the photosensitive element at least partially overlap in a direction in which the first substrate and the second substrate face each other; Wherein, the manufacturing method further comprises: A light shielding layer is covered directly above the driving circuit, and after the first substrate and the second substrate are arranged relative to each other for box alignment, the light shielding layer is closer to the second substrate than the driving circuit; forming a first passivation layer including an opening area on the driving circuit; forming a conductive connection portion in the opening region to connect the driving circuit and the photosensitive element; Among them, one electrode among the source and the drain of the transistor which is connected to the photosensitive element through a conductive connecting portion serves as the bottom electrode of the photosensitive element.

14. The method according to claim 13, further comprising: A conductive adhesive is disposed between the first substrate and the second substrate to bond the two substrates together.

15. The method according to claim 13, wherein: Forming the second substrate including the photosensitive element includes: forming a transparent electrode layer on a substrate of the second substrate, and then forming the photosensitive element on the transparent electrode layer.

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