X-ray detector

Abstract

The present invention provides an X-ray detector comprising: a first electrode and a second electrode on a substrate; and a photoelectric material layer which is formed between the first electrode and the second electrode and contains perovskite, the perovskite is formed into a cubic crystal structure, and the size of the perovskite crystal is 3 [mu] m to 10 [mu] m.

Description

X-ray detector Technical Field

[0001] This invention relates to an X-ray detector. Background Technology

[0002] Recently, digital detectors have been widely used in X-ray imaging.

[0003] X-ray detectors are classified into indirect conversion and direct conversion methods. In indirect conversion, a phosphor is used to convert X-rays into visible light, and the visible light is then converted into an electrical signal for detection. Conversely, in direct conversion, a photoconductor is used that absorbs X-rays and directly generates an electrical signal.

[0004] Perovskite has recently attracted much attention as a photoelectric material. However, current research indicates limitations in its use as a photoelectric material for X-ray detectors. Summary of the Invention

[0005] Technical Problem: The technical problem to be solved by this invention is to provide a solution for effectively using perovskite as a photoelectric material for X-ray detectors.

[0006] To address the aforementioned technical problems, the present invention provides an X-ray detector, comprising: a first electrode and a second electrode on a substrate; and a photoelectric material layer formed between the first electrode and the second electrode, and containing perovskite, wherein the perovskite is formed in a cubic crystal structure and the size of the perovskite crystal is 3μm~10μm.

[0007] Within the photoelectric material layer, the size of the perovskite crystal can gradually increase as it moves away from the substrate.

[0008] When the X-ray detector is used as a dental intraoral sensor or a mammography sensor, the thickness of the photoelectric material layer can be 50 μm to 200 μm.

[0009] When the X-ray detector is used as a sensor for dental cone-beam computed tomography (CBCT) or general radiography, the thickness of the photoelectric material layer can be 200 μm to 700 μm.

[0010] When the X-ray detector is used as a sensor for a dental multi-detector computed tomography (MDCT) scan, the thickness of the photoelectric material layer can be 0.7 mm to 2 mm.

[0011] The perovskite can be CsPbBr3, Cs2AgBiBr6, MAPbI3, or MAPbBr3.

[0012] Effects of the Invention According to the present invention, when using perovskite to form a photoelectric material layer, the size of the perovskite crystal is set to 3μm to 10μm, and within this size range, the size of the perovskite crystal gradually increases towards the upper direction, and the thickness of the photoelectric material layer is set in accordance with the intended use.

[0013] Therefore, the photoelectric material layer formed by perovskite can have excellent electrical properties while ensuring sufficient adhesion to the substrate, and the X-ray detector with it can be used in various X-ray imaging devices. Attached Figure Description

[0014] Figure 1 is a schematic diagram illustrating an X-ray detector according to an embodiment of the present invention.

[0015] Figure 2 is a schematic cross-sectional view of an X-ray detector according to an embodiment of the present invention.

[0016] Figure 3 is an enlarged cross-sectional view showing the photoelectric material layer according to an embodiment of the present invention. Detailed Implementation

[0017] Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings.

[0018] Figure 1 is a schematic diagram illustrating an X-ray detector according to an embodiment of the present invention. Figure 2 is a schematic cross-sectional view illustrating an X-ray detector according to an embodiment of the present invention. Figure 3 is an enlarged cross-sectional view showing the photoelectric material layer according to an embodiment of the present invention.

[0019] In addition, for ease of explanation, the first and second electrodes located at the lower and upper parts of the photoelectric material layer are omitted in Figure 3.

[0020] Referring to Figures 1 to 3, the X-ray detector 10 according to an embodiment of the present invention is equivalent to a direct conversion X-ray detector equipped with a photoelectric material layer 140.

[0021] The X-ray detector 10 may include: a sensor panel 100, a driving circuit section for driving the sensor panel 100, and a power supply circuit 300 for providing driving voltages (or power supply voltages) Vb and Vp for driving the X-ray detector 10.

[0022] The sensor panel 100 can be a sensor panel 100 that uses a direct conversion method to directly convert incident X-rays into electrical signals.

[0023] Although not specifically illustrated, the sensor panel 100 may include an effective area for actually receiving and detecting X-rays and a non-effective area located outside the effective area.

[0024] In the effective area, a pixel array consisting of multiple pixels P is arranged on the substrate 110. These multiple pixels P can be arranged in a matrix form along multiple row lines and multiple column lines.

[0025] Furthermore, multiple scan lines (or gate lines) SL extending along multiple row lines and multiple readout lines (or data lines) RL extending along multiple column lines can be arranged on the substrate 110. These scan lines SL and readout lines RL can be connected to the corresponding pixel P.

[0026] In addition, in this embodiment, the substrate 110 may be composed of a complementary metal-oxide-semiconductor (CMOS) substrate, a glass substrate, or a plastic substrate with flexible properties, but is not limited to these.

[0027] The driving circuit for driving the sensor panel 100 may include a scanning circuit 220 and a readout circuit 230.

[0028] The scanning circuit 220 applies a scanning signal with a conduction level by sequentially scanning the scan lines SL. As a result, each row line can be selected sequentially, and the data, as electrical signal data stored in the pixel P of the selected row line, is output to the corresponding readout line RL. Furthermore, the readout circuit 230 can receive the data stored in the pixel P through the readout line RL.

[0029] Each pixel P of the sensor panel 100 may be equipped with an optoelectronic element PC that detects X-rays and generates corresponding electrical signals.

[0030] In this regard, the optoelectronic component PC may include: a first electrode (or pixel electrode) 130 as a lower electrode formed on the substrate 110; a second electrode (or common electrode) 150 as an upper electrode located on the first electrode 130; and an optoelectronic material layer 140 disposed between the first electrode 130 and the second electrode 150.

[0031] The first electrode 130 can be formed in a patterned form corresponding to each pixel P. A pixel voltage Vp, which serves as a driving voltage, can be applied to the first electrode 130.

[0032] The photomaterial layer 140 formed on the first electrode 130 can, for example, be formed continuously along a plurality of pixels P actually arranged in the effective region. In other words, the photomaterial layer 140 can be formed corresponding to a plurality of pixels P arranged in the effective region.

[0033] Perovskite can be used as the photoelectric material for forming this photoelectric material layer 140.

[0034] In this respect, perovskite is equivalent to a substance with a crystal structure of ABX3. Here, A can be a monovalent cation, B can be a metal cation, and X can be a halide anion.

[0035] For example, such perovskite can be cesium lead bromide trihydrate (CsPbBr3), cesium silver bismuth bromide hexahydrate (Cs2AgBiBr6), cesium lead methyl sulfide trihydrate (MAPbI3), or cesium lead methyl sulfide trihydrate (MAPbBr3), but is not limited to these.

[0036] Alternatively, for example, the perovskite photoelectric material layer 140 can be formed by a solution process. In this case, a solution (or slurry) of a mixture of perovskite powder and solvent can be coated onto the substrate 110 on which the first electrode 130 is formed, and then formed through a curing process.

[0037] The second electrode 150 formed on the photoelectric material layer 140 may, for example, be formed continuously along a plurality of pixels P actually arranged in the effective region. In other words, the second electrode 150 may be formed corresponding to the plurality of pixels P arranged in the effective region. A bias voltage (i.e., reverse voltage) Vb, which is a driving voltage, may be applied to such the second electrode 150.

[0038] In addition, in this embodiment, the perovskite crystal 141 constituting the photoelectric material layer 140 can be configured as a cubic structure, thereby possessing excellent electrical properties.

[0039] Preferably, the size (or diameter) of the perovskite crystal 141 is, for example, 3 μm to 10 μm.

[0040] Relatedly, as the size of the perovskite crystal 141 increases, the porosity increases, which may reduce the adhesion to the substrate 110. In particular, since the perovskite photoelectric material layer 140 has a significantly different coefficient of thermal expansion from the substrate 110 due to its characteristics, the photoelectric material layer 140 may be removed (or peeled off) from the substrate 110 depending on the temperature. With this in mind, the size of the perovskite crystal 141 is preferably 10 μm or less.

[0041] Furthermore, if the size of crystal 141 is less than 3 μm, it is difficult to maintain a cubic structure. With this in mind, the size of perovskite crystal 141 is preferably 3 μm or larger.

[0042] Ultimately, considering the porosity and cubic crystal structure within the photoelectric material layer 140, the size of the perovskite crystal 141 can be set to approximately 3 μm to 10 μm.

[0043] Furthermore, in order to achieve the perovskite crystal 141 of the size described above, the size of the perovskite powder mixed in the solvent before coating can be approximately 3 μm to 7 μm.

[0044] Furthermore, as shown in FIG2, within the photoelectric material layer 140, the perovskite crystal 141 may be configured such that its size gradually increases in the upward direction (i.e., as it moves away from the substrate 110).

[0045] In other words, the size of the perovskite crystal 141 formed on the lower portion of the photoelectric material layer 140 near the substrate 110 can be relatively small, while the size of the perovskite crystal 141 formed on the upper portion of the photoelectric material layer 140 away from the substrate 110 can be larger.

[0046] As described above, by forming a small-sized perovskite crystal 141 with relatively large adhesion properties in a portion of the photoelectric material layer 140 near the substrate 110, the adhesion of the photoelectric material layer 140 to the substrate 110 can be effectively ensured.

[0047] As described above, regarding the structure in which the size of the crystal 141 gradually increases from the photoelectric material layer 140 toward the upper direction, during the curing process after coating the solution of mixed perovskite powder and solvent, heat is applied to the substrate 110 (more specifically, heat is applied to the lower part of the substrate 110), so that the solution near the side of the substrate 110 evaporates first, thereby causing the size of the perovskite crystal 141 to gradually increase along the upper direction.

[0048] For the curing conditions used in this curing process, for example, for the coated perovskite solution, a curing process of about 10 to 20 hours can be performed at a temperature of about room temperature to 90 degrees.

[0049] In addition, the thickness of the photoelectric material layer 140 containing the perovskite crystal 141 can be appropriately set considering the application of the X-ray imaging device (or purpose) of the X-ray detector 10.

[0050] Relatedly, for example, when the X-ray detector 10 is used as a dental intraoral sensor or a mammography sensor, the thickness of the photoelectric material layer 140 can be approximately 50 μm to 200 μm.

[0051] Furthermore, when the X-ray detector 10 is used as a sensor for dental cone-beam computed tomography (CBCT) or general radiography, the thickness of the photoelectric material layer 140 can be approximately 200 μm to 700 μm.

[0052] Furthermore, when the X-ray detector 10 is used as a sensor in a high-energy device such as a dental multi-detector computed tomography (MDCT) sensor, the thickness of the photoelectric material layer 140 can be approximately 0.7 mm to 2 mm.

[0053] As described above, in the embodiments of the present invention, when using perovskite to form the photoelectric material layer 140, the size of the perovskite crystal 141 is set to 3 μm to 10 μm, and within this size range, the size of the perovskite crystal 141 gradually increases towards the upper direction, and the thickness of the photoelectric material layer 140 is set in accordance with the intended use.

[0054] Therefore, the photoelectric material layer 140 formed using perovskite can have excellent electrical properties while ensuring sufficient adhesion to the substrate 110, and the X-ray detector 10 equipped with it can be used in various X-ray imaging devices.

[0055] The above-described embodiments of the present invention are examples of the invention, and can be freely modified within the scope of the spirit of the invention. Therefore, the present invention includes the appended claims and modifications of the invention within the same scope.

Claims

1. An X-ray detector, comprising: The first electrode and the second electrode on the substrate; And a photoelectric material layer is formed between the first electrode and the second electrode, and contains perovskite, wherein the perovskite is formed in a cubic crystal structure and the size of the perovskite crystal is 3μm~10μm.

2. The X-ray detector according to claim 1, wherein, Within the photoelectric material layer, the size of the perovskite crystal gradually increases with distance from the substrate.

3. The X-ray detector according to claim 1 or 2, wherein, In cases where the X-ray detector is used as a dental intraoral sensor or a mammography sensor, the thickness of the photoelectric material layer is 50 μm to 200 μm.

4. The X-ray detector according to claim 1 or 2, wherein, When the X-ray detector is used as a dental cone-beam computed tomography sensor or a general radiographic sensor, the thickness of the photoelectric material layer is 200 μm to 700 μm.

5. The X-ray detector according to claim 1 or 2, wherein, When the X-ray detector is used as a computed tomography sensor, such as a dental multi-row detector, the thickness of the photoelectric material layer is 0.7 mm to 2 mm.

6. The X-ray detector according to claim 1 or 2, wherein, The perovskite is CsPbBr3, Cs2AgBiBr6, MAPbI3, or MAPbBr3.

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