JP2006086985A - Semiconductor device, image reading unit, and image forming apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To prevent deformation of a semiconductor device due to heat generation and to obtain higher optical performance in a semiconductor device where an optical function element formed of a semiconductor such as line CCD and LED array is packaged with a plastic mode or the like. <P>SOLUTION: The optical function element 1 of line CCD is bonded to a heat sink 2 and is then packaged with a structure body 3 formed of an insulator such as plastic mold or the like. A projection 2b extending in the longitudinal direction of the heat sink 2 is formed and thereby a secondary cross-sectional moment of the heat sink 2 is enlarged to intensify the strength for warpage in the longitudinal direction. Shape of projection 2b of the heat sink 2 is set to become higher at the center thereof than the end part in view of balancing the warp between the center and end part in the longitudinal direction. The heat sink of the waving shape (including projection and recess) is formed by forming holes to the heat sink and bending the metal plate in order to obtain a large heating radiating area. A flat plane for fixing is formed with the heat sink 2 itself by extending both ends of the heat sink 2 to the external side of the structure body 3 and thereby the relevant semiconductor device can be mounted to the other device. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a semiconductor device provided with optical functional elements such as a CCD and an LED array, an image reading unit using the semiconductor device, and an image forming apparatus such as a copying machine and a facsimile.

  Conventionally, as such a semiconductor device, for example, there is one disclosed in Japanese Patent Application Laid-Open No. 2000-223603. This conventional semiconductor device is equipped with a semiconductor element chip. For the purpose of performing positioning with high accuracy when mounting this semiconductor device and obtaining a high heat dissipation effect even when mounted on a mounting board. Yes.

Metals with higher processing accuracy than ceramics are identified by exposing multiple locations on the mounting lands of the lead frame on which the semiconductor element chip is mounted from the window frame, and recognizing the exposed multiple locations during mounting. Positioning is possible using a mounting land made up of and the like. In addition, since the back surface of the mounting land is exposed through a window provided in the base frame, the semiconductor device is positioned with high accuracy by recognizing the exposed back surface of the mounting land. ing. Further, the heat generated in the semiconductor element chip is radiated from the exposed back surface of the mounting land to enhance the heat radiation effect.
JP 2000-223603 A

  In Patent Document 1, in order to increase the heat dissipation effect of the semiconductor, a hole is formed in the back surface of the insulating package, and the land surface is exposed to increase the heat dissipation effect. As another practical method, a heat sink is attached to the package to increase the heat dissipation effect. However, most of the surface of such a package is an insulator, but the land surface is a metal. Since these two members have different linear expansion coefficients, warpage occurs due to heat generation of the semiconductor element.

  Here, if the semiconductor element is a circuit of only an arithmetic circuit that does not have an optical function, even if warping occurs, no major problem will occur immediately unless the circuit is broken or the package is damaged. . However, when the semiconductor element is an optical functional element, if the package is warped, the element is also warped, and even if the amount of warping is fine, the optical characteristics may be affected.

  For example, if the element is a color line CCD for 600 dpi, even if a warp of about 10 μm occurs, the optical image formation state is destroyed, and the MTF characteristic (focus condition) of the read image is deteriorated. Optical characteristics may not be obtained. Therefore, in the case of an optical functional element, it is necessary to suppress warping as much as possible. Further, even if it is not an optical functional element, repeated warping eventually causes destruction of the package and contact, so it is preferable that the warping is as small as possible.

  However, in the method described in the prior art, since the land is flat, the insulator occupying most of the package and the metal of the land are affected by the heat generation of the semiconductor element, and due to the difference in the coefficient of linear expansion, Warp is easily generated, and the above problem occurs at this time.

  Further, in order to prevent warping, there is a method of matching the linear expansion coefficients of the insulator that occupies most of the package and the metal of the land (heat sink), but it is difficult to make them completely coincide. Even if the two match, it is difficult to match the linear expansion coefficients of the semiconductor chip and the land (heat sink). Also, plastic molding of semiconductor packages has been progressing due to the recent demand for cost reduction. However, the insulation, land (heat sink), and the linear expansion coefficient of the semiconductor chip, which occupy most of the package, are combined to warp. It is very difficult to reduce.

  Therefore, in order to solve the above problems, the present invention measures the stress generated by strain due to heat, reduces the warpage of the optical function element of the semiconductor, prevents the element and the heat sink from peeling, and improves the optical characteristics. The issue is to stabilize.

  According to a first aspect of the present invention, in the semiconductor device in which the optical function element is fixed to the heat sink and the optical function element is packaged in an insulator structure, the heat sink is the optical function element of the heat sink. A protrusion extending in the longitudinal direction is formed perpendicular to the element fixing surface on which is fixed.

  A second aspect of the present invention is the semiconductor device according to the first aspect, wherein a part of the protrusion is exposed to the atmosphere.

  A third aspect of the present invention is the semiconductor device according to the first or second aspect, wherein the protrusion of the heat radiating plate increases in height from the element fixing surface as it goes to a central portion in the longitudinal direction of the protrusion. It is characterized by becoming.

  Invention of Claim 4 is a semiconductor device as described in any one of Claims 1-3, Comprising: The processus | protrusion or hole of an unevenness | corrugation is provided in surfaces other than the element fixing surface of the said heat sink. Features.

  A fifth aspect of the present invention is the semiconductor device according to the fourth aspect, wherein the heat radiating plate is a sheet metal and is provided with uneven projections by bending.

  A sixth aspect of the present invention is the semiconductor device according to any one of the first to third aspects, wherein the heat radiating plate is made of an extruded material.

  A seventh aspect of the present invention is the semiconductor device according to any one of the second to sixth aspects, wherein the heat radiating plate includes a fixing portion for fixing the semiconductor device.

  The invention according to claim 8 is the semiconductor device according to claim 7, wherein the fixing portion is flush with an element fixing surface of the heat radiating plate and constitutes a bonding plane. .

  A ninth aspect of the present invention is the semiconductor device according to the seventh aspect, wherein the fixing portion is flush with an element fixing surface of the heat sink and has a fixing plane and a hole. .

  A tenth aspect of the invention is the semiconductor device according to any one of the first to ninth aspects, wherein the heat radiating plate is conductive and electrically grounded.

  Invention of Claim 11 is a semiconductor device as described in any one of Claims 1-10, Comprising: The said heat sink is electroconductive, The surface exposed to the atmosphere of the said heat sink is electrically insulated. It is characterized by being.

  Invention of Claim 12 is a semiconductor device as described in any one of Claims 1-11, Comprising: The structure which fixes the said heat sink and the said semiconductor device is connected by the good heat exchanger. Features.

  Invention of Claim 13 is a semiconductor device as described in any one of Claims 1-12, Comprising: The said heat sink and an optical function element are fixed with an adhesive agent, This adhesive agent is a silicon system adhesive agent It is characterized by being.

  A fourteenth aspect of the invention is the semiconductor device according to any one of the first to thirteenth aspects, wherein the optical functional element is a solid-state imaging element.

  A fifteenth aspect of the invention is an image reading unit comprising the semiconductor device according to the fourteenth aspect.

  A sixteenth aspect of the present invention is an image forming apparatus comprising the image reading unit according to the fifteenth aspect.

  According to the invention of claim 1, even if contraction occurs in each component in the semiconductor device due to heat generated by the optical functional element, there is a protrusion extending in the longitudinal direction perpendicular to the element fixing surface of the heat sink, The strength of the heat sink in the bending direction is increased, and deformation is less likely to occur. That is, the bending force due to the difference in linear expansion coefficient between the optical functional element and the heat radiating plate is generated particularly in the longitudinal direction, but the strength against the warping in the longitudinal direction of the heat radiating plate is strong. Thereby, the fluctuation | variation of the position and attitude | position of an optical function element decreases, and an optical function can be ensured stably.

  According to the second aspect of the present invention, since a part of the protrusion is exposed to the atmosphere, the heat generated from the optical functional element can be effectively released to the atmosphere through the heat sink, so that the temperature of the semiconductor device is increased. It is suppressed and deformation is less likely to occur. Thereby, the fluctuation | variation of the position and attitude | position of an optical function element decreases, and an optical function can be ensured stably. Since the heat dissipation effect can be improved, when the semiconductor is a CCD chip, the temperature of the chip can be lowered, and the read image quality can be improved by reducing the level in the dark.

  According to the invention of claim 3, since the protrusion of the heat sink becomes higher as it goes to the center, the strength in the longitudinal direction becomes higher as it goes to the center, and the balance between the warp at the center and the end can be balanced. Therefore, the amount of warpage can be reduced with the minimum necessary material, the fluctuation of the position and posture of the optical functional element is reduced, and the optical function can be secured stably. Note that the cost can be reduced by using less material.

  According to invention of Claim 4, since the uneven | corrugated protrusion or hole is provided in surfaces other than the element fixing surface of a heat sink, the surface area of a heat sink becomes large and the heat generated from the optical functional element is dissipated. Therefore, the temperature rise of the semiconductor device can be suppressed and the deformation is less likely to occur. Thereby, the fluctuation | variation of the position and attitude | position of an optical function element decreases, and an optical function can be ensured stably.

  According to the invention of claim 5, since the heat sink is a sheet metal and provided with uneven projections by bending, it is possible to make a heat dissipation structure without significantly increasing the component cost, and the surface area of the heat sink increases. Since the heat generated from the optical functional element can be effectively released to the atmosphere via the heat dissipation plate, the temperature rise of the semiconductor device is suppressed and deformation is less likely to occur. Thereby, the fluctuation | variation of the position and attitude | position of an optical function element decreases, and an optical function can be ensured stably.

  According to invention of Claim 6, since the heat sink is comprised by the extrusion material, in addition to the effect of Claims 1-3, the surface precision of the element fixing surface with respect to an optical function element can be made high, and an optical function Since the deformation can be reduced when the element is fixed, the position and posture of the optical function element are less changed at the initial fixing stage, and the optical function can be stably secured.

  According to the invention of claim 7, in addition to the effects of claims 2 to 6, the heat sink has a fixing portion for fixing the semiconductor device of the invention to, for example, a fixing member of the image reading unit. The semiconductor device can be stably fixed, and an optical function can be stably secured.

  According to the invention of claim 8, in addition to the effect of claim 7, the fixing part is flush with the element fixing surface of the heat radiating plate and constitutes a bonding plane. The accumulated amount of misalignment from the bonding plane to the bonding plane can be reduced, and highly accurate positioning can be performed, thereby reducing fluctuations in the position and orientation of the optical functional element and ensuring stable optical functions. .

  According to the ninth aspect of the present invention, in addition to the effect of the seventh aspect, since the fixing portion is flush with the element fixing surface of the heat sink and has the fixing plane and the hole, the fixing portion is fixed from the surface of the optical functional element. The amount of misalignment up to the plane for use is reduced, high-accuracy positioning is possible, and the holes make it possible to fix firmly when tightening with screws, reducing fluctuations in the position and orientation of optical functional elements. The optical function can be secured stably.

  According to the invention of claim 10, in addition to the effects of claims 1 to 9, since the heat sink is electrically conductive and electrically grounded, it is electrically floating in the semiconductor device of the present invention. Things are lost, the stability against electromagnetic noise is increased, and the optical function can be secured stably.

  According to the eleventh aspect of the invention, in addition to the effects of the first to tenth aspects, the heat sink is electrically conductive, and the surface exposed to the atmosphere is electrically insulated. There is no need to take measures to short-circuit with surrounding parts, such as when installed in other devices. Further, it is possible to eliminate danger such as electric shock to a person. Further, the electric shock that enters from the outside through the heat radiating plate is eliminated, and damage to the optical functional element can be eliminated.

  According to the invention of claim 12, in addition to the effects of claims 1 to 11, since the heat sink and the structure for fixing the semiconductor device of the present invention are connected by a good heat transfer body, Since the generated heat can be effectively released to the atmosphere via the heat dissipation plate, the temperature rise of the semiconductor device body is suppressed and deformation is less likely to occur. Thereby, the fluctuation | variation of the position and attitude | position of an optical function element decreases, and an optical function can be ensured stably. Since the heat dissipation effect can be improved, when the semiconductor is a CCD chip, the temperature of the chip can be lowered, and the read image quality can be improved by reducing the level in the dark.

  According to the invention of claim 13, in addition to the effects of claims 1 to 12, the adhesive that fixes the heat sink and the optical functional element is a silicon-based adhesive, so the hardness of the adhesive after curing is reduced. The distortion due to the difference in coefficient of linear expansion between the heat sink and the optical functional element can be effectively reduced, and the overall warpage of the semiconductor device of the present invention can be reduced. Thereby, the fluctuation | variation of the position and attitude | position of an optical function element decreases, and an optical function can be ensured stably.

  According to the invention of claim 14, in addition to the effects of claims 1 to 13, the optical functional element is a solid-state image sensor, and an optical function can be stably secured in the solid-state image sensor, and high imaging performance is achieved. Obtainable.

  According to the fifteenth aspect of the present invention, a highly reliable image reading unit with high imaging performance can be obtained by the semiconductor device of the fourteenth aspect.

  According to the sixteenth aspect, the image reading unit according to the fourteenth aspect can provide a highly reliable image forming apparatus with high imaging performance.

  Hereinafter, embodiments of the present invention will be described. FIG. 1 is a perspective view of the semiconductor device of the first embodiment, and FIG. 2 is a cross-sectional view taken along line AA in FIG. This first embodiment is an embodiment corresponding to claims 1, 2, 6, 10, 11, and 13. In the cross-sectional view of the figure, for the sake of easy understanding, the scale in the height direction is changed for each part, and the hatched lines indicating the cross section are omitted as appropriate.

  The optical functional element 1 is a 600 dpi color line CCD (solid-state imaging device), and the optical functional element 1 is bonded to the heat sink 2 with an adhesive 12 (FIG. 2). The optical functional element 1 includes an optical functional part 1a for receiving light and an electrode part 1b, and the optical functional element 1 has an electrode part 1b with respect to a lead 5 for exchanging electrical signals with the outside. Are electrically connected by wire bonding 6. The optical functional element 1, part of the heat sink 2, part of the wire bonding 6, and part of the lead 5 are packaged by a structure 3 that is an insulator of a plastic mold. The portion of the structure 3 where the optical functional element 1 is disposed is a concave recess 3 a, and the opening of the recess 3 a is sealed with a translucent member 4. The optical function unit 1 a of the optical function element 1 faces the translucent member 4 and receives light incident from the translucent member 4. The translucent member 4 is a glass plate, the hole lead 5 is a 42 alloy, and the wire bonding 6 is a gold wire. The adhesive 12 is a silicon-based adhesive (for example, TSE322SX manufactured by GE Toshiba Silicone).

  As shown in FIG. 2, the heat radiating plate 2 packaged in the insulator structure 3 is formed by cutting an extruded aluminum material into a predetermined length (Claim 6). The heat radiating plate 2 has an element fixing surface 2a for fixing the optical functional element 1, and a protrusion 2b extending perpendicularly to the element fixing surface 2a and extending in the longitudinal direction of the heat radiating plate 2 (the direction of arrow P in FIG. 1). (Claim 1). Thus, since the protrusion 2b is perpendicular to the element fixing surface 2a and extends in the longitudinal direction, the secondary sectional moment of the heat radiating plate 2 is increased, and the strength against warping in the longitudinal direction is increased. Further, only a part of the heat radiating plate 2 is packaged by the structure 3, and the protrusion 2b is exposed to the atmosphere (Claim 2). Accordingly, it is possible to suppress an increase in the temperature of the entire semiconductor device that can effectively release the heat generated from the optical functional element 1 to the atmosphere via the heat dissipation plate 2. Therefore, deformation due to heat is less likely to occur.

Furthermore, the optical functional element 1 is fixed to the heat radiating plate 2 with an adhesive 12, and the adhesive 12 is a silicon-based adhesive as described above (claim 13). For this reason, the hardness of the adhesive agent 12 after hardening can be made low, and the distortion by the difference in the linear expansion coefficient of the heat sink 2 and the optical function element 1 can be relieve | moderated effectively. Therefore, the overall warpage of the semiconductor device can be reduced.
I can keep it.

  The heat radiating plate 2 is conductive, but if it is conductive, it is not preferable that it is electrically floating from the viewpoint of noise. Therefore, the back surface of the optical functional element 1 is used as an electrical grounding surface and the adhesive 12 is used. It is preferable that the heat radiating plate 2 is grounded to the outside through the adhesive 12, the optical function element 1 (its ground surface) and the lead 5. However, the method of grounding the heat sink 2 is not limited to this, and the heat sink 2 may be grounded directly from the outside of the semiconductor device with a wire, a spring, or the like. In this case, the adhesive 12 is used as described above. Needless to say, a silicon adhesive may be used.

  As shown in FIG. 2, at least a portion of the heat radiating plate 2 exposed from the structure 3 is covered with an insulating film 2c. Thereby, the surface exposed to the atmosphere of the heat sink 2 is electrically insulated. Therefore, even if the semiconductor device is incorporated in another device, it does not short-circuit with surrounding components, and there is no danger of electric shock to people. Furthermore, the electric shock that enters from the outside through the heat radiating plate 2 is eliminated, and damage to the optical functional element 1 can be eliminated. The insulating film 2c is provided as necessary and may not be provided.

  The length of the projection 2b of the heat radiating plate 2 exposed to the outside in the direction of extension (the direction orthogonal to the element fixing surface 2a) is shorter than the length of the legs of the lead 5 when the projection 2b is mounted. Although it is easy to mount without hitting the base or the like, the length in the extending direction of the protrusion 2b may be longer than the length of the leg of the lead 5 if a measure is taken to escape the portion corresponding to the heat sink 2 on the substrate.

  FIG. 3 is a perspective view of the semiconductor device according to the second embodiment, and corresponds to the third embodiment. In the following embodiments, elements corresponding to those in the first embodiment are denoted by the same reference numerals as those in FIGS. 1 and 2, and detailed description thereof is omitted. In the second embodiment, the shape of the heat sink 2 in the first embodiment is changed, and the height of the central portion of the heat sink 2 (height from the element fixing surface 2a) is increased. ). The edge 2P of the heat radiating plate 2 is linear, but the edge 2P may be curved as long as the central portion 2Q is higher than the end 2R. Thus, in this 2nd Embodiment, since the protrusion 2b of the heat sink 2 becomes high as it goes to the center part 2Q from the edge part 2R, the intensity | strength of a longitudinal direction (arrow P direction of a figure) goes to a center part. The warpage at the center portion 2Q and the end portion 2R can be balanced, and the amount of warpage can be reduced with the minimum necessary material for the heat radiating plate 2. And the fluctuation | variation of the position and attitude | position of an optical function element decreases, and an optical function can be ensured stably. Note that the cost can be reduced by using less material.

  FIG. 4 is a perspective view of the semiconductor device according to the third embodiment, which corresponds to claim 4. In this 3rd Embodiment, the shape of the heat sink 2 in 1st Embodiment is changed, and the several hole 7 is formed in the part of the processus | protrusion 2b of the heat sink 2 (Claim 4). This hole 7 is provided in order to increase the surface area of the heat radiating plate 2, and the position and size can be freely set without being limited to the position and size in the drawing as long as the strength is structurally secured. Thereby, the heat generated from the optical functional element 1 can be effectively released to the atmosphere via the heat radiating plate 2.

  FIG. 5 is a perspective view of a semiconductor device according to a fourth embodiment, which corresponds to claims 7 and 8. In the fourth embodiment, the shape of the heat sink 2 in the first embodiment is extended in the longitudinal direction, and the fixed portion A of the semiconductor device is arranged at the end of the heat sink 2 (Claim 7). The fixing part A has a parallel surface 8 that is the same plane as the element fixing surface 2a for the optical function element 1, and a vertical surface 8 'that is a surface perpendicular to the element fixing surface 2a. Both can be used as a fixing plane of the semiconductor device. In addition, the parallel surface 8 is the same plane as the element fixing surface 2a of the heat sink 2, and is also configured as a bonding plane. If the size of the bonding plane is about 1 cm × 1 cm, it is easy to bond, but the size may be set according to the size of the semiconductor device. As described above, the parallel surface 8 of the fixed portion A is the same plane as the element fixing surface 2a of the heat radiating plate 2 and constitutes a bonding plane. The accumulated amount of misalignment up to is reduced, and highly accurate positioning can be performed.

  FIG. 6 is a perspective view of a semiconductor device according to a fifth embodiment, which corresponds to claims 7 and 9. In the fifth embodiment, the shape of the heat sink 2 in the first embodiment is extended in the longitudinal direction, and the fixing portion B of the semiconductor device is arranged at the end 2R of the heat sink 2 (Claim 7). . The fixing part B has a parallel surface 9 and a hole 10 which are the same plane as the element fixing surface 2a for the optical functional element 1, and a vertical surface 9 'and a hole 10' which are surfaces perpendicular to the element fixing surface 2a. And have. Both the parallel surface 9 and the vertical surface 9 'can be used as a fixing plane of the semiconductor device. In addition, the parallel surface 9 is the same plane as the element fixing surface 2a of the heat sink 2, and is also configured as a fixing plane. Although it is easy to fix if the size of the fixing plane is about 1 cm × 1 cm, the size may be set according to the size of the semiconductor device. Thus, since the parallel surface 9 in the fixing part B is the same plane as the element fixing surface 2a of the heat radiating plate 2 and constitutes a fixing plane, the fixing plane extends from the surface of the optical functional element 1. The accumulated amount of misalignment up to is reduced, and highly accurate positioning can be performed. Moreover, although the holes 10 and 10 'are round holes, they may be long holes or screw holes if necessary.

  Each of the above embodiments is an example of a member in which the heat radiating plate 2 is formed of, for example, an aluminum extrusion material. For example, as shown in FIG. 7, the heat radiating plate 2 'is formed by bending a sheet metal. May be used. In this case as well, the portion exposed from the structure 3 may be covered with the insulating film 2c ′, but the insulating film 2c ′ may be omitted. Thus, if it comprises with sheet metal, component cost can be reduced. Further, when the heat radiating plate is formed of sheet metal in this way, it is preferable that the projections 2b 'be provided with the concavo-convex portions 11 by bending the sheet metal, as shown in FIG. 8, for example. . Since the corrugated portion 11 has a wave shape in this way, a heat dissipation structure can be made without significantly increasing the component cost, and the surface area of the heat dissipation plate 2 'is increased, so that the heat generated from the optical functional element 1 can be increased. Can be effectively released to the atmosphere through the heat sink.

  As described above, in each embodiment, the scale in the height direction is changed for each part. However, the thickness of the optical functional element 1 is about 1 mm, the translucent member 4 is several mm, and the heat sink 2 is The thickness of the adhesive 12 is several mm, and the thickness of the adhesive 12 is about 0.1 mm. The adhesive layer has a very thin structure.

  Further, since the optical functional element 1 is thin, the interval between the leads 5 and 5 on both sides is narrow in the concave portion of the structure 3 where the optical functional element 1 is disposed. For this reason, the structure is such that the leads 5 and 5 and the heat radiating plate 2 easily interfere with each other. Therefore, electrical shorting may be prevented by squeezing the heat radiating plate 2 at the part facing the leads 5 and 5 or by squeezing the gap between the leads 5 and 5 and extending the wire bonding 6 longer. . Further, in the heat radiating plate 2, at least a portion facing the leads 5 and 5 (not a portion exposed to the atmosphere) may be electrically insulated.

  In the semiconductor devices of the above embodiments, the optical function element 1 is a solid-state image sensor (line CCD). FIG. 9 is a perspective view showing an embodiment of an image reading unit 100 including a semiconductor device 50 using such a solid-state imaging device, and corresponds to claims 15 and 12. The semiconductor device 50 is, for example, the semiconductor device according to the fourth embodiment, and the semiconductor device 50 is bonded and fixed to the cradle 23 (structure for fixing the semiconductor device) via the fixing portion A and the fixing member 22. Further, an imaging element (lens) 21 is also fixed to the cradle 23 via a fixing member 24, and a reading document (not shown), an imaging element (lens) 21, and an optical function element (solid-state imaging element) 1. The optical positional relationship is formed. Then, reflected light from the original is received by the imaging element 21 and an image is projected onto the optical functional element 1 of the semiconductor device 50, and the image is read by the optical functional element 1 and converted into an image signal. The fixing method of the semiconductor device 50 is not limited to this, and may be screwed or the like as long as the positional accuracy can be secured. Further, the heat radiating plate 2 of the semiconductor device 50 is connected to the pedestal 23 by the good heat transfer body 13, and has a structure in which the heat generated in the semiconductor device is released to the iron pedestal 23 (claim 12). ).

  FIG. 10 is a diagram illustrating an embodiment of an image forming apparatus 200 including the image reading unit 100 according to the embodiment. The embodiment corresponds to claim 16. The image forming apparatus 200 is a multifunction digital image forming apparatus. As shown in FIG. 10, the image forming apparatus including the image reading unit 100 includes an automatic document feeder 101, a reading unit 150, a writing unit 157, A sheet feeding unit 130 and a post-processing unit 140 are provided. The automatic document feeder 101 automatically feeds a document onto the contact glass 106 of the reading unit 150, and automatically discharges the document that has been read. The reading unit 150 includes a contact glass 106 on which an original is placed and an optical scanning system. The optical scanning system includes an exposure lamp 151, a first mirror 152, an image reading unit 100, a second mirror 155, a third mirror 156, and the like. It has become. The reading unit 150 illuminates the original set on the contact glass 106 and reads it by the image reading unit 100, and the writing unit 157 forms an image on the photoconductor 115 according to the image signal of the read original. Then, the image is transferred and fixed on the transfer sheet fed from the sheet feeding unit 130. After the fixing is completed, the transfer paper is discharged to the post-processing unit 140, and desired post-processing such as sorting and stapling is performed.

  In the above embodiment, aluminum is used as the conductive heat sinks 2 and 2 '. However, a heat sink made of silver, copper, or the like becomes a material having higher thermal conductivity, and thus higher heat dissipation is expected. it can. In addition, the optical functional element 1 in each embodiment has been described mainly using a line CCD as a solid-state imaging element. However, the optical functional element 1 may be a light emitting element such as an LED array. Stable functions can be secured and high performance can be obtained.

  In addition to the above embodiments, the following configuration may be adopted. The configuration in which the height increases as it goes to the center as in the heat radiation plate 2 in the second embodiment (FIG. 3), and the configuration in which the hole 7 is provided in the third embodiment (FIG. 4) are shown in FIG. 7 or FIG. Thus, the present invention can also be applied to a heat sink made of sheet metal. Further, in the fourth embodiment (FIG. 5) or the fifth embodiment (FIG. 6), the configuration in which the parallel surfaces 8, 9 and the vertical surfaces 8 ', 9' are provided is a heat radiating plate made of sheet metal as shown in FIG. It can also be applied to. Moreover, as shown in FIG. 2 or FIG. 7, the insulating film provided on the surface exposed to the atmosphere of the heat sink may or may not be present in each embodiment.

1 is a perspective view of a semiconductor device according to a first embodiment of the present invention. It is AA sectional drawing in FIG. 1 of this invention. It is a perspective view of the semiconductor device of 2nd Embodiment of this invention. It is a perspective view of the semiconductor device of 3rd Embodiment of this invention. It is a perspective view of the semiconductor device of 4th Embodiment of this invention. It is a perspective view of the semiconductor device of 5th Embodiment of this invention. It is sectional drawing which shows embodiment of the semiconductor device using the heat sink of the sheet metal of this invention. It is a perspective view of the semiconductor device of embodiment which provided the uneven | corrugated | grooved part in protrusion by bending of the sheet metal in this invention. It is a perspective view of the image reading unit in the embodiment of the present invention. 1 is a diagram illustrating an image forming apparatus according to an embodiment of the present invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Optical function element 2, 2 'Heat sink 2a Element fixed surface 2b, 2b' Protrusion 2c, 2c 'Insulating film 3 Structure 4 Translucent member 5 Lead 6 Wire bonding 7 Hole A, B Fixed part 8, 9 Parallel surface 8 ', 9' Vertical surface 11 Concavity and convexity 12 Adhesive 13 Heat transfer body 50 Semiconductor device 100 Image reading unit 22 Fixing member 23 Receiving base 21 Imaging element (lens)
200 Image forming apparatus

Claims (16)

In the semiconductor device in which the optical functional element is fixed to the heat sink and the optical functional element is packaged in an insulator structure,
2. A semiconductor device according to claim 1, wherein the heat radiating plate is formed with a protrusion extending in a longitudinal direction perpendicular to an element fixing surface to which the optical function element of the heat radiating plate is fixed.   The semiconductor device according to claim 1, wherein a part of the protrusion is exposed to the atmosphere.   3. The semiconductor device according to claim 1, wherein the protrusion of the heat radiating plate increases in height from the element fixing surface as it goes to a central portion in the longitudinal direction of the protrusion.   The semiconductor device according to any one of claims 1 to 3, wherein an uneven protrusion or hole is provided on a surface other than the element fixing surface of the heat radiating plate.   The semiconductor device according to claim 4, wherein the heat radiating plate is a sheet metal, and uneven protrusions are provided by bending.   The semiconductor device according to claim 1, wherein the heat radiating plate is made of an extruded material.   The semiconductor device according to claim 2, wherein the heat sink has a fixing portion for fixing the semiconductor device.   The semiconductor device according to claim 7, wherein the fixing portion is flush with an element fixing surface of the heat radiating plate and constitutes a bonding plane.   The semiconductor device according to claim 7, wherein the fixing portion is flush with an element fixing surface of the heat sink and has a fixing plane and a hole.   The semiconductor device according to claim 1, wherein the heat radiating plate is electrically conductive and is electrically grounded.   The semiconductor device according to claim 1, wherein the heat radiating plate is conductive, and a surface of the heat radiating plate exposed to the atmosphere is electrically insulated.   The semiconductor device according to claim 1, wherein the heat sink and the structure that fixes the semiconductor device are connected by a good heat transfer body.   The semiconductor device according to claim 1, wherein the heat dissipation plate and the optical functional element are fixed by an adhesive, and the adhesive is a silicon-based adhesive.   The semiconductor device according to claim 1, wherein the optical function element is a solid-state imaging element.   An image reading unit comprising the semiconductor device according to claim 14.   An image forming apparatus comprising the image reading unit according to claim 15.

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