JP2009111149A - Solid-state imaging apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To simultaneously solve problems of both defective light reception or image blurring caused by flaw or dust sticking to the surface of a translucent member and that caused by bedewing which occurs on the rear surface of the translucent member. <P>SOLUTION: The solid-state imaging apparatus comprises a hollow package 1 where a solid-state imaging element 3 is mounted, and a translucent member 2 for sealing the package 1. The optical incidence side of the region containing a main beam transmission region of the translucent member 2 is made convex, being thicker than other region. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a solid-state imaging device, and more particularly to a solid-state imaging device having a hollow structure.

  FIG. 9 is a diagram illustrating a general structure of a solid-state imaging device having a conventional hollow structure.

  1 is a hollow package made of ceramic or plastic, 2 is a translucent member, 3 is a solid-state imaging device, 5 is a light receiving portion, 6 is a resin adhesive, 7 is a wiring conductor (lead) for connection to an external substrate ). Reference numeral 4 denotes a wire for connecting the solid-state imaging device 3 and the lead 7.

  The solid-state imaging device 3 is mounted on the bottom surface of the recess of the package 1 by being bonded with a thermosetting resin adhesive or the like.

  Further, an electrode is formed on the outer peripheral portion of the surface of the solid-state imaging device 3, and this electrode and the wiring conductor 7 are electrically connected by a wire 4 such as gold or aluminum.

  In addition, on the upper surface of the package 1, a flat plate-like translucent member 2 is disposed via a photocurable or thermosetting resin adhesive 6.

  With such a configuration, the solid-state imaging element is hermetically sealed with the light-transmitting member and the package. In this way, deterioration of the solid-state image sensor due to the penetration of dust or moisture existing outside into the hollow is prevented.

Such a conventional solid-state imaging device is disclosed in Patent Document 1 or Patent Document 2.
JP 05-343658 A Japanese Patent Laid-Open No. 06-29505

  In a conventional solid-state imaging device, when a foreign substance adheres to the front and back surfaces of a translucent member, a light beam entering the light receiving unit may be blocked, resulting in poor light reception or image blur.

  The foreign matter that has a high possibility of adhering to the surface of the translucent member is dust adhering from the atmosphere at the time of manufacture or scratches generated in the manufacturing process.

  Then, if dust or scratches occupy a certain ratio or more with respect to the area of the pixels arranged in the light receiving portion, light reception failure or image blur occurs.

  On the other hand, the foreign matter that has a high possibility of adhering to the back surface of the translucent member is dew condensation that occurs due to a decrease in temperature.

  In particular, the hollow interior of the solid-state imaging device inevitably contains moisture present in the air in the atmosphere at the time of manufacture, and at the same time, the resin adhesive, the resin adhesive, and the translucent member or package Moisture infiltrated from the interface is also present.

  When such moisture is contained in the hollow interior, when the temperature drops, the air in the hollow interior is cooled, and condensation occurs in the hollow interior when the amount of saturated water vapor is exceeded.

  In particular, in recent years, there has been a demand for thin translucent members accompanying the miniaturization of solid-state imaging devices, and the translucent member has a thickness of, for example, about 0.3 mm to 1.5 mm. Is often used.

  When the translucent member having such a thickness is used, the heat capacity of the translucent member is often lower than the heat capacity of the package, and the translucent member is cooled before the package. As a result, condensation occurs on the back surface of the translucent member.

  When dew condensation occurs in the principal ray transmission region on the back surface of the translucent member, the light ray entering the light receiving unit is blocked, the light amount of the light ray entering the light receiving unit is reduced, and light reception failure or image blur occurs.

  Therefore, the present invention eliminates both light reception failure or image blur caused by dust or scratches adhering to the surface of the light transmissive member and light reception failure or image blur caused by condensation occurring on the back surface of the light transmissive member. The purpose is to solve simultaneously.

  The present invention provides a solid-state imaging device comprising a hollow package on which a solid-state imaging element is mounted and a translucent member that seals the package as means for solving the above-described problems. The light incident side of the region including the principal ray transmission region is formed in a convex shape that is thicker than the other regions.

  According to the present invention, since the region including the principal ray transmission region of the translucent member is made thicker than the other regions, dew condensation that occurs when the temperature decreases can be selectively generated in addition to the principal ray transmission region. As a result, it is possible to suppress poor light reception or image blur during photographing.

  In addition, by forming a part of the light incident side of the translucent member (the surface side of the translucent member) into a convex shape, the distance between the translucent member surface and the light receiving surface can be increased. As a result, even when foreign matter or condensation adheres to the surface of the translucent member, it is possible to suppress light reception failure or image blur at the time of shooting up to a larger foreign matter.

  DESCRIPTION OF THE PREFERRED EMBODIMENTS The best mode for carrying out the present invention will be described below with reference to the accompanying drawings.

[First embodiment]
FIG. 1 is a perspective view showing a solid-state imaging device as a first embodiment of the present invention. FIG. 2 is a cross-sectional view showing the solid-state imaging device shown in FIG.

  1 and 2, 1 is a hollow package made of ceramic or plastic, 2 is a translucent member for sealing the package, 3 is a solid-state image sensor, 5 is a light-receiving portion of the solid-state image sensor, and 6 is a resin bond It is an agent. Reference numeral 4 denotes a wire for connecting the solid-state imaging device 3 and a lead (not shown).

  As shown in FIGS. 1 and 2, in the present embodiment, a part of the light incident side of the translucent member 2 has a convex shape, and the convex region is a principal ray transmission region described later. It is formed including.

  L1 is the thickness of the convex region of the translucent member 2, L2 is the thickness of the translucent member 2 in the peripheral region other than the convex region, and the thickness of the translucent member 2 is L1> L2. .

  Since the heat capacity of the translucent member 2 is proportional to the volume of the material, the heat capacity increases as the translucent member 2 becomes thicker. That is, when the heat capacities are compared, the convex region> the peripheral region, and when the temperature decreases, the peripheral region is cooled earlier than the convex region.

  Therefore, dew condensation occurs when the saturated water vapor amount is exceeded due to the temperature drop, and the generated water selectively adheres to the peripheral portion of the back surface of the translucent member 2, thereby preventing dew condensation in the convex region. . As a result, condensation does not occur in the principal ray transmission region, and poor light reception or image blur at the time of photographing can be suppressed.

  Moreover, in this embodiment, the convex-shaped area | region is provided in the light-incidence side (surface side of the translucent member 2) of the translucent member 2 at least.

  By forming a convex shape on the surface side of the translucent member 2, the distance between the surface of the translucent member 2 and the light receiving surface is increased, and foreign matter such as dust or scratches attached to the surface of the translucent member is removed. On the other hand, it is possible to suppress light reception failure or image blur at the time of shooting up to a larger foreign object.

  This effect will be described with reference to FIG.

  FIG. 3 is a side view used for explaining a case where foreign matters such as dust or scratches exist at different heights from the light receiving unit.

  In FIG. 3, 3 is a solid-state imaging device, 5 is a light-receiving portion of the solid-state imaging device, 9 is a pixel disposed in the light-receiving portion, 10 is a foreign matter such as dust or scratches, 11 is a surface of a translucent member, and 12 is a pixel. Shows the rays that enter.

  Here, it is assumed that the light beam 12 entering the pixel is imaged with a 5 ° spread with respect to the axis in the normal direction of the pixel surface. Consider the case where the translucent member surface 11 is located 2.5 mm away from the pixel and the case where the translucent member surface 11 is located 3.5 mm away from the pixel.

When the translucent member surface 11 is located 2.5 mm away from the pixel, the area of the light beam 12 entering the pixel is π · (2.5 tan 5 °) ² = 0.15 mm ² . Assuming that light reception failure occurs when 10% of the pixels are shielded, the allowable size of the foreign matter is 0.015 mm ² .

On the other hand, when the translucent member surface 11 is located 3.5 mm away from the pixel, the area of the light beam 12 entering the pixel is π · (3.5 tan 5 °) ² = 0.29 mm ² . From the same calculation, the allowable size of foreign matter is 0.029 mm ² , and the allowable range can be expanded to larger foreign matters.

  As the convex shape of the translucent member 2, it is preferable that the convex region and the peripheral region have a uniform thickness, and the side wall of the convex region has a steep step.

  By making the thickness uniform in both the convex region and the peripheral region and forming a steep step on the side wall surface, the heat capacity of the convex region and the peripheral region can be changed abruptly.

  As a result, it is possible to reliably cause condensation only in the peripheral area, in other words, it is possible to prevent the occurrence of condensation in the principal ray transmission area.

  Moreover, it is possible to make the size of the translucent member 2 as small as possible by forming an abrupt step.

  For example, a right-angled convex shape as shown in FIG. 4 (a) or a tapered convex shape as shown in FIG. 4 (b) is preferable as the shape for making a steep step. .

  In particular, in the tapered shape, the side wall surface is less likely to be chipped. Therefore, it becomes possible to prevent the translucent member from cracking or cracking starting from the chipping.

  However, if the taper angle is too large, it becomes difficult to add a sudden capacity change, or the area of the translucent member becomes large and the cost increases. Therefore, the angle formed between the surface and the side surface of the convex region is preferably about 90 ° to 130 °.

  Further, the ratio L1 / L2 of the thickness of the convex region and the peripheral region of the translucent member 2 for giving a sharp heat capacity difference is preferably 1.05 or more, and prevents dew condensation on the principal ray transmission region. Is possible.

  Furthermore, the principal ray transmission region that defines the convex region of the translucent member 2 will be described with reference to the cross-sectional view shown in FIG.

  In FIG. 5, 1 is a hollow package made of ceramic or plastic, 2 is a translucent member, 3 is a solid-state imaging device, 5 is a light-receiving part of the solid-state imaging device, 6 is a resin adhesive, and 8 is a principal ray transmission region. It is. Reference numeral 4 denotes a wire for connecting the solid-state imaging device 3 and a lead (not shown).

  Since the light beam entering the light receiving unit 5 is collected by a lens or the like, the light beam has a certain angle with respect to the normal direction of the light receiving surface, and a region through which the light beam passes in the translucent member 2 is mainly used. It is defined as a light transmission region 8.

  The area of the convex region of the translucent member 2 is set to be larger than the principal ray transmission region so as to include this principal ray transmission region.

  For example, assuming that the principal ray transmission region forms an image on the light receiving portion with a 5 ° spread with respect to the normal axis of the light receiving surface, for example, 5 ° outside the normal direction of the light receiving surface. The region extended in the region is the region through which the chief ray passes.

  When the distance between the back surface of the translucent member and the light receiving surface is 2 mm and the thickness L1 of the convex region is 1.5 mm, the distance between the end of the principal ray on the surface of the translucent member is 3.5 × tan5. ° = 0.31 mm. If a region wider than the light receiving end by 0.31 mm or more is formed in a convex shape, an image can be formed without disturbing the principal ray.

  FIG. 1 is a diagram in which the inside of the four edge portions of the chief ray transmission region is convex, but as shown in FIGS. 6 and 7, only the inner side of the two sides of the chief ray transmission region is convex. The same effect can be achieved even in the case of.

  Moreover, as a material of a translucent member, it is a transparent member, For example, the thing of plastic materials, such as glass and an acryl, can be used. In particular, in the case of a translucent member made of a plastic material such as acrylic, a convex shape can be formed by resin molding simply by pouring resin into a mold, which is more preferable in terms of productivity.

[Second Embodiment]
FIG. 8 is a cross-sectional view showing a solid-state imaging device as a second embodiment of the present invention.

  The present embodiment is different from the first embodiment in that not only the light incident side of the translucent member 2 has a convex shape, but also the back side of the translucent member 2 has a convex shape.

  1 is a hollow package made of ceramic or plastic, 2 is a translucent member, 3 is a solid-state image sensor, 5 is a light-receiving portion of the solid-state image sensor, and 6 is a resin adhesive. Reference numeral 4 denotes a wire for connecting the solid-state imaging device 3 and a lead (not shown).

  In FIG. 8, the convex shape of the chief ray transmitting region is formed on the front and back sides of the translucent member.

  With this shape, it is possible to increase the thickness of the hollow inner side, to induce a more rapid change in capacity, and to improve the selectivity for the occurrence of condensation.

  Further, by forming the convex shape also on the back surface side, the volume inside the hollow is reduced, and the amount of air inside the hollow can be reduced.

  Thereby, since the moisture content in the hollow derived from moisture in the air at the time of manufacturing the solid-state imaging device is reduced, it is possible to suppress the amount of condensation generated when the temperature is lowered.

  As a result, it is possible to reduce the probability of occurrence of problems such as moisture that adheres to the periphery of the principal ray transmitting region on the back surface of the translucent member, dropping and fouling the pixel area on the image sensor.

  The present invention is applicable to a solid-state imaging device having a hollow structure.

1 is a perspective view showing a solid-state imaging device as a first embodiment of the present invention. It is sectional drawing which shows the solid-state imaging device shown in FIG. It is a side view used in order to explain a case where foreign matters such as dust or scratches exist at different heights from the light receiving unit. It is a schematic cross section which shows the example of the side wall shape of a translucent member. It is sectional drawing used in order to demonstrate a chief ray transmission area | region. It is a perspective view which shows the example of the shape of a translucent member. It is a perspective view which shows the example of the shape of a translucent member. It is sectional drawing which shows the solid-state imaging device as the 2nd Embodiment of this invention. It is a figure which shows the general structure of the solid-state imaging device which has the conventional hollow structure.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Package 2 Translucent member 3 Solid-state image sensor 4 Wire 5 Light-receiving part 6 Resin adhesive 7 Wiring conductor (lead)
8 Principal ray transmission area 9 Pixel 10 Foreign matter such as dust, scratch, etc. 11 Translucent member surface 12 Light entering the pixel

Claims (8)

In a solid-state imaging device comprising a hollow package on which a solid-state imaging element is mounted and a translucent member that seals the package,
A solid-state imaging device, wherein a light incident side of a region including a principal ray transmitting region of the translucent member is formed in a convex shape that is thicker than other regions. The solid-state imaging device according to claim 1, wherein the convex region is also provided on a back surface of the translucent member. 3. The solid-state imaging device according to claim 1, wherein thicknesses of the convex region and a peripheral region other than the convex region are uniform. 4. The solid-state imaging device according to claim 1, wherein a side wall of the convex region is tapered. 5. The solid-state imaging device according to claim 4, wherein an angle of the taper is about 90 ° to 130 °. The solid-state imaging device according to claim 1, wherein the translucent member is manufactured by resin molding. The solid-state imaging device according to claim 6, wherein a material of the translucent member is a plastic material. 8. The solid-state imaging device according to claim 1, wherein a ratio of a thickness of the convex region to a thickness of the peripheral region is 1.05 or more.