JP2012028550A - Sensor package, imaging device, and portable electronic appliance - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a sensor package that can suppress image deterioration caused by temperature fluctuation while attempting space saving, provide an imaging device including the sensor package, and provide a portable electronic appliance including the imaging device.SOLUTION: A sensor package 10 comprises: a flat-plate shaped translucent substrate 12 provided with a metal wire on one surface; a flat-plate shaped solid-state imaging element 9 disposed opposite to the translucent substrate 12 and electrically connected to the metal wire; connection terminals 13, 13... electrically connected to a part of the metal wire that is outside the solid-state imaging element 9; and a flat-plate shaped printed circuit board 14 disposed opposite to the solid-state imaging element 9 and electrically connected thereto by the connection terminals 13, 13.... As for selection of the translucent substrate 12 and the printed circuit board 14, one of the substrates 12 and 14 has a linear expansion coefficient 1-3 times that of the other in the range of a linear expansion coefficient of 3.2(×10) to 7.2(×10).

Description

  The present invention relates to a sensor package, an imaging device having the sensor package, and a portable electronic device including the imaging device.

  2. Description of the Related Art In recent years, an imaging device is mounted on an electronic device such as a mobile phone or a car navigation device, and is widely used.

  For example, as shown in FIG. 5, the imaging device 15 is disposed at a predetermined distance from the lens 16 as an optical system, a lens holder 17 that accommodates the lens 16, and the lens 16, and at the center thereof. A sensor package 22 provided with a solid-state image sensor (for example, a CMOS image sensor or a CCD image sensor) 21 having a light receiving portion, and a printed circuit board 23 on which the sensor package 22 is mounted (Patent Document) 1).

JP 2005-266276 A

  However, in the imaging device 15 of Patent Document 1, the solid-state imaging device 21 is connected to the printed circuit board 23 by lead wires 24 extending on both sides thereof, and is sealed in the sensor package 22. There was a problem of increasing the size. The imaging device 15 includes an optical system including a plurality of lenses 16. The plurality of lenses 16 are held in the lens holder 17 in a state where the lenses 16 are arranged in the optical axis direction, and the lens holder 17, the plurality of lenses 16, and the like. This forms a space where the outside is blocked. For this reason, for example, when the imaging device 15 is used in a car navigation device, heat is trapped in the imaging device 15 due to a rapid rise in the vehicle interior temperature, and the image quality of the solid-state imaging device 21 is deteriorated due to the influence of the heat. There was a problem.

  The present invention has been made in view of the above-described problems, and includes a sensor package that can suppress image quality deterioration due to temperature fluctuations while saving space, an imaging apparatus having the sensor package, and the imaging apparatus. An object is to provide a portable electronic device.

  The sensor package of the present invention includes a flat light-transmitting substrate having a metal wiring formed on one side thereof, and a flat light-transmitting substrate disposed opposite to the light-transmitting substrate and electrically connected to the metal wiring. A solid-state image sensor, a connection terminal electrically connected to a portion outside the solid-state image sensor of the metal wiring, and the connection terminal arranged to be opposed to and electrically connected to the solid-state image sensor. A flat printed circuit board having a linear expansion coefficient of 3.2 (× 10 −6) to 7.2 (× 10 − 6) Within the range, one having a linear expansion coefficient of one to three times of the other substrate is selected.

  According to such a configuration, since it is connected to the printed circuit board by connection terminals such as solder balls, instead of being connected to the printed circuit board by lead wires extending on both sides of the solid-state imaging device as in the background art, Space can be saved. Further, the translucent substrate and the printed circuit board have a linear expansion coefficient within a range of 3.2 (× 10 −6) to 7.2 (× 10 −6), and one of the linear expansion coefficients of the respective substrates is By selecting the other one having a linear expansion coefficient of 1 to 3 times, the mechanical stress generated in the connection terminal due to the difference in thermal expansion is reduced, and the metal wiring of the translucent board or printed circuit board and the connection terminal are reduced. Connection failure can be prevented, and as a result, image quality deterioration of the solid-state imaging device due to temperature fluctuation can be suppressed.

  According to a second aspect of the present invention, the connection terminal is a solder ball having a resin core therein.

  According to such a configuration, since the solder ball having a resin core inside is used as the connection terminal, it acts on the connection terminal as compared with the case of using a solder ball composed only of conventional solder. Mechanical stress can be reduced, and the connection between the translucent board and the printed circuit board can be made flexible.

  According to a third aspect of the present invention, an imaging apparatus of the present invention comprises the above-described sensor package and a lens for forming an image of a subject on the imaging surface of a solid-state imaging device of the sensor package. Features.

According to such a configuration, since it is connected to the printed circuit board by connection terminals such as solder balls, instead of being connected to the printed circuit board by lead wires extending on both sides of the solid-state imaging device as in the background art, Space can be saved. Further, the translucent substrate and the printed circuit board have a linear expansion coefficient within a range of 3.2 (× 10 ⁻⁶ ) to 7.2 (× 10 ⁻⁶ ), and one of the linear expansion coefficients of the respective substrates is By selecting the other one having a linear expansion coefficient of 1 to 3 times, the mechanical stress generated in the connection terminal due to the difference in thermal expansion is reduced, and the metal wiring of the translucent board or printed circuit board and the connection terminal are reduced. Connection failure can be prevented, and as a result, image quality deterioration of the solid-state imaging device due to temperature fluctuation can be suppressed.

  According to a fourth aspect of the present invention, a portable electronic device according to the present invention includes the above-described imaging device.

  According to this configuration, it is possible to take an image such as an image or a video obtained by the above-described downsized imaging device.

  The present invention relates to a flat light-transmitting substrate having a metal wiring formed on one surface, and a flat solid-state imaging device that is disposed opposite to the light-transmitting substrate and is electrically connected to the metal wiring. And a connection terminal electrically connected to a portion outside the solid-state image sensor of the metal wiring, and a flat plate shape disposed opposite to the solid-state image sensor by the connection terminal and electrically connected The light-transmitting substrate and the printed circuit board each have a linear expansion coefficient within a range of 3.2 to 7.2 (× 10 −6). A space-saving sensor package that can suppress deterioration in image quality of a solid-state imaging device due to temperature fluctuation by selecting one having a linear expansion coefficient of one to three times that of the other substrate, and the sensor package Imaging device and mobile phone It is possible to provide a child equipment.

Schematic diagram of portable electronic device according to the present embodiment Sectional view of the imaging device incorporated in the portable electronic device Top view of sensor package used in the imaging device Cross section of the sensor package Sectional view of a conventional imaging device

  Hereinafter, a car navigation device as an embodiment of a portable electronic device according to the present invention will be described with reference to the accompanying drawings.

  As shown in FIG. 1, a car navigation device 1 according to this embodiment includes a device main body 2 having a rectangular display unit 2a for displaying an image, a video, and the like, and a built-in display device. And an imaging device 3 disposed at a position near the long side 2a (more specifically, a position near the long side middle).

  The display unit 2a is composed of, for example, a liquid crystal display panel, and displays an image, video, or the like captured by the imaging device 3, and also serves as a display device for car navigation.

  As shown in FIG. 2, the imaging device 3 includes a plurality of lenses 4 that collect an optical image of a subject on the imaging element 9, a lens holder 5 that houses the range 4, and a plurality of lenses via the lens holder 5. A cylindrical outer holder 6 that accommodates the lens 4, an infrared cut filter 8, and a solid-state imaging device 9 (not shown) that is disposed at a predetermined distance from the lens 4 and that has a light receiving portion at the center thereof. Sensor package 10.

The lens holder 5 accommodates a plurality (three in FIG. 1) of lenses 4. The lens 4 for condensing the optical image of the subject on the solid-state imaging device 9 has been described as being a plurality of lenses in the present embodiment, but is not limited to this and may be a single lens.
The plurality of lenses 4 form an image of the subject on the light receiving unit 9 a (imaging surface) of the solid-state imaging device that constitutes the sensor package 10. An opening 5 a is provided in the upper part of the lens holder 5. The opening 5 a functions as a diaphragm for the plurality of lenses 4. A male screw (not shown) is formed on the outer surface of the lens holder 5.

  The outer holder 6 has a substantially cylindrical outer shape and has an internal thread (not shown) formed on the inner surface thereof. The male screw of the lens holder 5 is screwed into this female screw, and the plurality of lenses 4, the lens holder 5, and the outer holder 6 are arranged concentrically.

  The infrared cut filter 8 is provided at a position between the plurality of lenses 4 and the sensor package 10. Specifically, the infrared cut filter 8 is fixed to the upper surface of a base 6 a provided at the bottom of the outer holder 6. Then, the images formed on the plurality of lenses 4 are condensed on the light receiving unit 9 a of the solid-state imaging device 9 via the infrared cut filter 8.

  As shown in FIGS. 3 and 4, the sensor package 10 is disposed so as to face the translucent substrate 12 and the rectangular translucent substrate 12 in which the metal wiring 12 a is formed on one surface. A solid-state imaging element 9 having a rectangular shape smaller than the area of the translucent substrate 12 and electrically connected and fixed to the metal wiring 12a of the translucent substrate 12 through solder bumps (or solder balls) 9b, and the metal wiring 12a. Among them, it has connection terminals 13, 13... Made of solder balls that are electrically connected and fixed to a portion outside the solid-state imaging device 9, and a region surface that covers the translucent substrate 12. A square printed circuit board 14 disposed opposite to the element 9 and electrically connected and fixed to the connection terminals 13, 13... The connection terminals 13, 13... Extend along opposite two sides of the solid-state image sensor 9 so as to form a gap serving as a gas or liquid flow path 30 between the solid-state image sensor 9 and the printed circuit board 14. Are provided.

    The translucent substrate 12 is made of a glass or ceramic material having a coefficient of thermal expansion (linear expansion coefficient) of 3.2 (× 10 −6) to 7.2 (× 10 −6). For example, a copper wiring metal pattern 12a (metal wiring 12a) is formed on the surface (the lower surface in the present embodiment) in the width direction (long side direction). The metal pattern 12a is baked by applying a resinate to the translucent substrate 12 by screen printing, transfer printing, or the like, and heating the resinate. In this embodiment, a resinate containing copper is used.

  As will be described later, the metal pattern 12a is fixedly connected to the solder bumps 9b of the solid-state image pickup device 9 and fixedly connected to the connection terminals 13, 13. The element 9 is connected to the connection terminals 13, 13. That is, the solid-state imaging device 9 and the connection terminals 13, 13,... Are electrically connected to each other through the metal pattern 12a. The thickness of this metal pattern 12a is about 3 μm to 10 μm. The connection terminals 13, 13... Will be described in detail later.

  A solder paste (not shown) is interposed as a conductive paste to electrically connect the metal pattern 12a and the solder bump 9b. Further, a solder paste (not shown) is interposed as a conductive paste so as to electrically connect the connection terminals 13, 13... And the metal pattern 12a.

  The solid-state imaging device 9 has a rectangular light receiving portion 9a at the center of one surface (on the translucent substrate 12 side), converts an optical image formed by the plurality of lenses 4 into an electrical signal, and outputs the electrical signal. . Specifically, the solid-state imaging device 9 is configured by, for example, a CMOS image sensor, a CCD image sensor, or the like.

  As described above, the solid-state image pickup device 9 includes the solder bumps 9 b that are fixed portions fixed to the translucent substrate 12. The solid-state imaging device 9 is fixed to the light-transmitting substrate 12 by connecting and fixing (welding) the solder bumps 9b to the light-transmitting substrate 12.

  The printed circuit board 14 is formed of a ceramic material having a coefficient of thermal expansion (linear expansion coefficient) of 7.0 (× 10 −6) to 7.2 (× 10 −6). A plurality (two in this embodiment) of the printed circuit board 14 are provided at the position of the inlet or outlet of the flow path 30 and at the end of the printed circuit board 14, in the corner of the printed circuit board 14 in this embodiment. A circuit component 14b is attached. An example of the circuit component 14b is a ceramic capacitor. When the circuit component 14b is provided on the outlet side of the configuration, particularly the flow path 30, the circuit component 14b is cooled without losing the cooling effect of the solid-state imaging device 9.

  The printed circuit board 14 has a copper wiring metal pattern (metal wiring 14a) 14a formed on one surface (the upper surface in the present embodiment). The metal pattern 14a is fired by applying a resinate to the printed circuit board 14 by screen printing or transfer printing and heating the resinate. In this embodiment, a resinate containing copper is used.

  In this embodiment, for example, the connection terminals 13, 13... Made of solder balls are opposed to the short side of the sensor package 10 (solid-state image sensor 9) between the solid-state image sensor 9 and the printed circuit board 14. A plurality are arranged along two sides. That is, the connection terminals 13, 13... Are opposed to the short side of the solid-state image sensor 9 so as to form a gap serving as a gas or liquid flow path between the solid-state image sensor 9 and the printed circuit board 14. A plurality are arranged along two sides.

  As described above, the connection terminals 13, 13... Are electrically connected to the translucent substrate 12 through the metal pattern 12 a disposed on the lower surface of the translucent substrate 12, and are printed circuit boards. The printed circuit board 14 is electrically connected via a metal pattern (copper wiring pattern) 14 a disposed on the upper surface of the printed circuit board 14.

  With such a configuration, the imaging device 3 (sensor package 10) according to the present embodiment is sealed in the sensor package 10 by connecting the solid-state imaging device 9 to the printed circuit board 14 by lead wires extending on both sides thereof. Compared to a conventional imaging device, it can be miniaturized and allows gas or liquid to circulate through a gap as a gas or liquid flow path formed between the solid-state imaging device 9 and the printed circuit board 14. Therefore, the heat dissipation effect of the solid-state image sensor 9 can be enhanced.

  A method of manufacturing the sensor package 10 configured as described above and the imaging device 3 including the sensor package 10 will be described.

  In order to manufacture the sensor package 10, first, the metal pattern 12 a is formed on the translucent substrate 12. In order to form the metal pattern 12a on the translucent substrate 12, first, a resinate (for example, copper resinate) for forming the metal pattern 12a is applied to a predetermined position of the translucent substrate 12 by screen printing or the like. Then, this resinate is heated at a predetermined temperature and fired as a metal pattern 12a.

  Similarly, a metal pattern 14 a is formed on the printed circuit board 14. In order to form the electrode pattern 14 a on the printed circuit board 14, first, a resinate (for example, W resinate) for forming the metal pattern 14 a is applied to a predetermined position of the printed circuit board 14 by screen printing or the like. Then, this resinate is heated at a predetermined temperature and fired as an electrode pattern 14a.

  Next, the solid-state imaging device 9 is hermetically fixed to the translucent substrate 12. At this time, a solder paste (not shown) is applied to a predetermined position of the metal pattern 12a, and solder bumps 9b of the solid-state image pickup device 9 are fixed thereon, and the outer peripheral portion of the solid-state image pickup device 9 is made of resin (not shown). ). Subsequently, the connection terminals 13, 13... Are fixed to a part of the electrode pattern 12 a of the translucent substrate 12. At this time, a solder paste (not shown) is applied on the metal pattern 12a at a position where the connection terminals 13, 13... Are fixed. The connection terminals 13, 13... Are fixed to the electrode pattern 12a of the translucent substrate 12 through this solder paste.

  Next, the connection terminals 13, 13... Are fixed to a part of the metal pattern 14 a of the printed circuit board 14. At this time, a solder paste (not shown) is applied on the metal pattern 14a at positions where the connection terminals 13, 13... Are fixed. The connection terminals 13, 13... Are fixed to the electrode pattern 14a of the printed circuit board 14 through this solder paste.

  Then, with the connection terminals 13, 13... Interposed between the translucent substrate 12 and the printed circuit board 14, the substrate is heated in a reflow furnace. By this heating, the connection terminals 13, 13... Are fixed to the metal patterns 12a and 14a via the solder paste, respectively. Thus, the sensor package 10 is completed.

  As described above, according to the present embodiment, in the sensor package 10, the solid-state imaging device 9 is not connected to the printed circuit board 14 by the lead wires extending on both sides thereof, but the translucent board 12 is Since it is connected to the printed circuit board 14 by a plurality of connection terminals 13, 13... Provided along two opposing sides on the short side of the solid-state imaging device 9, compared to a conventional imaging device, The width between the solid-state imaging device 9 and the printed circuit board 14 can be reduced, and the imaging device 3 having the sensor package 10 can be downsized.

  Further, by forming a gap as a gas or liquid flow path between the solid-state imaging device 9 and the printed circuit board 14, gas or liquid can flow through the gap, and heat can be trapped in the imaging device 3. In addition, the heat radiation effect of the solid-state imaging device 9 can be enhanced. As a result, it is possible to reduce image quality degradation due to thermal noise of the solid-state image sensor 9. Further, since the gas or liquid flow passage is provided, it is easy to remove dust, dust and the like in the flow passage.

  By the way, as described above, each of the translucent substrate 12 and the printed circuit board 14 has a thermal expansion coefficient (linear expansion coefficient) of 3.2 (× 10 −6) to 7.2 (× 10 −6). It is made of material. Moreover, the translucent board | substrate 12 and the printed circuit board 14 are electrically connected through the terminal 13 for connection, 13, .... Therefore, when the imaging device 3 having the sensor package 10 is used for the car navigation device 1, a difference in thermal expansion between the translucent board 12 and the printed circuit board 14 due to a sudden rise in the in-vehicle temperature or the like is caused by the connection terminal. There is a case where high stress is generated in the connection terminals 13, 13.

  Therefore, the translucent board 12 and the printed circuit board are prevented so that the difference in thermal expansion between the translucent board 12 and the printed circuit board 14 does not directly act on the connection portions of the connection terminals 13, 13. It is conceivable to make the connection with the connector 14 flexible and reduce the mechanical stress generated in the connection terminals 13, 13.

  Therefore, in the connection terminals 13, 13... According to the present embodiment, solder balls that are formed of solder and have a resin core therein may be used.

Therefore, in the sensor package 10, the glass substrate (linear expansion coefficient is 3.8 (× 10 −6)) which is the translucent substrate 12 is made constant, various printed circuit boards and connection terminals are changed, and the heat is changed. Impact resistance experiments (test conditions and methods) were conducted. The results of thermal shock resistance experiments are shown below. In addition, the following thermal shock evaluation results are displayed as the number of times (number of cycles) that mechanical stress due to heat is applied to the sensor package 10 according to the present embodiment.
(Example)
1. When a conventional FR-4 substrate (linear expansion coefficient is 16 (× 10−6)) is used as the printed circuit board 14 and normal solder balls are used as the connection terminals 13, 13. The thermal shock evaluation result of 10 was 300 cyc (number of cycles).

  2. As the printed circuit board 14, an FR-4 board (linear expansion coefficient is 13 (× 10-6)) having a low expansion coefficient compared to the conventional FR-4 board is used as the connection terminals 13, 13,. When a normal solder ball was used, the thermal shock evaluation result of the sensor package 10 was 400 cyc (number of cycles).

  3. As the printed circuit board 14, an FR-4 board (linear expansion coefficient is 13 (× 10-6)) having a low expansion coefficient compared to the conventional FR-4 board is used as the connection terminals 13, 13,. When a solder ball having a resin core inside was used, the thermal shock evaluation result of the sensor package 10 was 500 cyc (number of cycles).

  4). As the printed circuit board 14, a ceramic material having a thermal expansion coefficient (linear expansion coefficient) of 7.0 (× 10 −6) to 7.2 (× 10 −6) is used as the connection terminals 13, 13. When a normal solder ball was used, the thermal shock evaluation result of the sensor package 10 was 3000 cyc (number of cycles) or more.

  5). As the printed circuit board 14, a ceramic having a thermal expansion coefficient (linear expansion coefficient) of 7.0 (× 10 −6) to 7.2 (× 10 −6) is used as the connection terminals 13, 13. When a solder ball having a resin core therein was used, the sensor package 10 thermal shock evaluation result was 3000 cyc (number of cycles) or more.

  From the above results, ceramics having a thermal expansion coefficient (linear expansion coefficient) of 7.0 (× 10 −6) to 7.2 (× 10 −6) are used as the printed circuit board 14, and the connection terminals 13 and 13 are used. When the solder ball having a resin core inside is used, the thermal shock evaluation result of the sensor package 10 is the best, and is generated in the connection terminals 13, 13. We think that it is possible to reduce mechanical stress. The thermal shock resistance experiment is still in progress.

  Based on the thermal shock evaluation results and the like, in order to put the imaging device 3 used in the car navigation device into practical use (about 1000 cyc or more), the translucent substrate 12 and the printed circuit board 14 constituting the sensor package 10 have a linear expansion coefficient. In a material in the range of 3.2 (× 10 −6) to 7.2 (× 10 −6), the linear expansion coefficient of one of the light transmitting substrate 12 and the printed circuit board 14 is the linear expansion of the other substrate. It is possible to select one having a coefficient of 1 to 3 times (more preferably, a linear expansion coefficient of 1 to 2.5 times and about 2000 cyc or more, and more preferably a linear expansion coefficient of 1 to 2 times and about 3000 cyc or more). preferable.

  In addition, this invention is not limited to the said embodiment, Of course, it can change suitably in the range which does not deviate from the summary of this invention.

  In the sensor package 10 according to the present embodiment, a plurality of connection terminals 13, 13... Are arranged along two opposing sides on the short side of the solid-state imaging device 9. A plurality of connection terminals 13, 13... May be arranged along two opposing sides on the long side of the solid-state imaging device 9. Even with such a configuration, the width between the solid-state imaging device 9 and the printed circuit board 14 can be narrowed compared to the conventional imaging device, and the imaging device 3 having the sensor package 10 can be downsized. In addition, the heat radiation effect of the solid-state image sensor 9 can be enhanced. From this point of view, the plurality of connection terminals 13, 13... May be arranged along three sides or all four sides of the solid-state imaging device 9. According to this configuration, since the number of connection terminals 13 and 13 is further increased, mechanical stress generated in one of the connection terminals 13 and 13 due to a difference in thermal expansion can be further reduced.

  In the present embodiment, an example in which the solid-state imaging device 9 and the connection terminals 13, 13... Are fixed to the translucent substrate 12 and the printed circuit board 14 with a solder paste is shown. However, the present invention is not limited to this, and solder paste may not be used. In this case, the metal patterns 12a and 14a are connected to the solid-state imaging device 9 and the connection terminals 13, 13... By applying flux to the portions where the metal patterns 12a and 14a are in contact and heating. The bumps may be made of a metal other than solder. For example, bumps such as gold, silver, and copper can be employed. In this case, instead of the solder paste, another metal paste or conductive adhesive may be employed.

  A sensor package according to the present invention includes a flat light-transmitting substrate having a metal wiring formed on one surface thereof, and a flat plate that is disposed opposite to the light-transmitting substrate and is electrically connected to the metal wiring. A solid-state image pickup device, a connection terminal electrically connected to a portion outside the solid-state image pickup device of the metal wiring, and the connection terminal opposed to the solid-state image pickup device and electrically connected thereto A flat printed circuit board having a linear expansion coefficient of 3.2 (× 10 −6) to 7.2 (× 10 10). -6) Within the range, since one of the substrates has a coefficient of linear expansion of 1 to 3 times that of the other, mechanical stress generated in the connection terminal due to the difference in thermal expansion Reduced, translucent substrate or printed circuit Connection failure between the metal wiring of the road board and the connection terminal can be prevented, and the present invention can also be applied to applications such as a car navigation device that needs to be used at a high temperature, a mobile phone that is used in a high temperature environment, and a camera.

DESCRIPTION OF SYMBOLS 1 Car navigation apparatus 2 Apparatus main body 2a Display part 3 Imaging device 4 Several lenses 5 Lens holder 6 Outer holder 8 Infrared cut filter 9 Solid-state image sensor 9a Light-receiving part 9b Solder bump 10 Sensor package 12 Translucent board | substrates 12a and 14a Metal pattern 13 , 13 Connection terminal 14 Printed circuit board 14b Multiple circuit components

Claims (4)

A flat light-transmitting substrate having a metal wiring formed on one surface, a flat solid-state imaging device disposed opposite to the light-transmitting substrate and electrically connected to the metal wiring, and a metal wiring A connection terminal electrically connected to a portion outside the solid-state image sensor, and a flat printed circuit board disposed and electrically opposed to the solid-state image sensor by the connection terminal And the light-transmitting substrate and the printed circuit board have a linear expansion coefficient in a range of 3.2 (× 10 ⁻⁶ ) to 7.2 (× 10 ⁻⁶ ), and A sensor package wherein one of the substrates has a linear expansion coefficient of 1 to 3 times the other. The sensor package according to claim 1, wherein the connection terminal is a solder ball having a resin core therein. An image pickup apparatus comprising: the sensor package according to claim 1; and a lens for forming an image of a subject on an image pickup surface of the solid-state image pickup device of the sensor package. A portable electronic device comprising the imaging device according to claim 4.

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