JP2008160757A - Imaging apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an imaging apparatus capable of positioning and fixing an optical filter, such as an optical low-pass filter accurately with respect to an imaging element without using a dedicated jig. <P>SOLUTION: On a circuit board 20 with an imaging element 1 mounted therein, a shield case 30 for shielding the imaging element from electrical noise is mounted. An opening for guiding external light to the imaging element 1 is formed on the shield case 30 and by fitting an optical filter 10 to the opening, the optical filter 10 is positioned with respect to the imaging element. Furthermore, the shield case 30 comprises a bent part 34 bending an edge portion of the opening to a side of the imaging element 1. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to an imaging apparatus including an optical filter disposed on an optical path of light incident on an imaging element and a shield case that shields electrical noise.

  2. Description of the Related Art Conventionally, a system in which an imaging device is mounted in the vicinity of a bumper of a vehicle, a side mirror, or the like to image the vicinity of the vehicle and display the captured image on a display provided in the vicinity of the driver's seat of the vehicle has been widely used. These imaging devices are desired to be as small as possible so as not to impair the aesthetic appearance of the vehicle. In addition, it is desired to take a high-quality image by reducing the influence of noise radiated from other electronic devices mounted on the vehicle as much as possible.

  FIG. 5 is a schematic cross-sectional view showing a configuration of a conventional imaging apparatus. In the figure, reference numeral 1 denotes an image pickup device. A CCD chip 2 is enclosed in a package 3 having a substantially rectangular plate shape, and a light-transmitting face glass 4 is provided on one surface of the package 3 to transmit light to the CCD chip 2. I can do it. A plurality of leg-shaped connection terminals 5 are provided on the opposite surface or side surface of the package 3, and the connection terminals 5 are soldered to the circuit board 20 to mount the imaging device 1 on the circuit board 20. . An optical filter 10 having a configuration in which an optical low-pass filter 11 and an infrared cut filter 12 are laminated is adhered to the face glass 4 of the image sensor 1 with an adhesive or the like, and the wavelength of light incident on the image sensor 1 through a lens (not shown). And so on.

  In addition to the image pickup device 1, a plurality of electronic components (not shown) such as a DSP, a resistor, or a capacitor are mounted on the circuit board 20, and the image pickup device includes an image pickup device mounted on the circuit board 20, and an image pickup device. A shield case 130 is provided for shielding other electronic components from electrical noise. The shield case 130 has a casing shape having a top surface and a peripheral surface, and the peripheral surface is engaged with the side portion of the circuit board 20 so as to cover the surface of the circuit board 20 on which the imaging device 1 is mounted. It is fixed by a method such as screwing or bonding. The image sensor 1 and other electronic components mounted on the circuit board 20 are accommodated in a shield case 130 and are shielded from the outside by the shield case 130. In addition, an opening for allowing light condensed from the lens (not shown) to the image sensor 1 to pass through is formed on the top surface of the shield case 130.

  The CCD chip 2 of the image sensor 1 has a large number of light receiving elements (pixels) that accumulate charges in accordance with received light in a matrix, and digital data corresponding to the amount of charge accumulated in each pixel. Can be acquired as image data. The minimum size of a subject that can be imaged by the image sensor 1 is determined by the size of the photosensitive portion of the pixel (pixel size) and the interval between pixels (pixel pitch). The optical low-pass filter 11 of the optical filter 10 blurs an image of a subject smaller than the minimum size and forms it on the image sensor 1 so that the image sensor 1 can image the subject. The infrared cut filter 12 is for removing infrared rays incident on the image sensor 1.

In Patent Document 1, an accommodation opening for accommodating the optical filter is formed in the light shielding cover, an abutment portion and an engagement convex portion are formed on the inner periphery of the accommodation opening, and the optical filter is pushed into the accommodation opening. An optical filter that can be attached to an imaging device at low cost without shakiness by accommodating an optical filter in the light shielding cover and fixing the light shielding cover to a lens holder arranged in front of the CCD element. A holding device has been proposed.
Japanese Patent Laying-Open No. 2005-309051

  The infrared cut filter 12 of the optical filter 10 provided in the image pickup apparatus does not require high positional accuracy with respect to the mounting position with respect to the image pickup element 1, and it is sufficient that at least the region where the pixels of the CCD chip 2 are disposed is covered. However, since the optical low-pass filter 11 of the optical filter 10 requires a high positional accuracy in the mounting position with respect to the arrangement direction of a plurality of pixels arranged in parallel on the CCD chip 2, conventionally, the optical low-pass filter 11 is used in an assembling process of the imaging device. Therefore, it is necessary to use a high-precision positioning jig when bonding the optical filter 10 to the image sensor 1. In addition, when the mounting position of the optical filter 10 with respect to the imaging device 1 is displaced, the optical filter 10 and the shield case 130 interfere when the shield case 130 is attached to the circuit board 20 in the assembly process. There is a possibility that the shield case 130 cannot be attached to the circuit board 20.

  In the optical filter holding device described in Patent Document 1, the optical filter can be easily attached to the imaging device simply by housing the optical filter in the housing opening formed in the light shielding cover. Since it is a structure to be fixed and not directly bonded to the CCD element, a high accuracy is required for a fixing position with respect to the CCD element such as a light shielding cover and a lens holder, and from the outside after the imaging apparatus is assembled. Due to the impact, there is a possibility that the fixed positions of the light shielding cover, the lens holder and the like are displaced, and the function of the optical filter is deteriorated. Therefore, it is difficult to apply to holding an optical filter such as an optical low-pass filter that requires high positional accuracy at the mounting position.

  The present invention has been made in view of such circumstances, and an object of the present invention is to utilize an aperture for allowing light incident on an image sensor formed in a shield case to pass therethrough, and to provide an optical An object of the present invention is to provide an imaging apparatus capable of easily and accurately positioning the optical filter with respect to the imaging element by bringing the side surface portion of the filter into contact with the imaging element.

  In addition, another object of the present invention is that the shape of the opening of the shield case is a shape that is externally fitted to the optical filter, so that the optical filter can be positioned reliably, and the mounting position of the optical filter can be reduced. An object of the present invention is to provide an imaging apparatus in which no deviation occurs.

  Another object of the present invention is to provide an image pickup in which the optical filter is mounted on the image pickup device so that no deviation occurs in the mounting position of the optical filter after the optical filter is mounted on the image pickup device. To provide an apparatus.

  In addition, another object of the present invention is that the contact area between the edge portion of the opening and the side surface portion of the optical filter is increased by bending the edge portion of the opening of the shield case toward the image sensor side. An object of the present invention is to provide an imaging apparatus that can easily position an optical filter.

  Another object of the present invention is to determine from a pixel interval of the image sensor when the spatial period of the subject image formed on the image sensor by the lens is shorter than the pixel interval of the image sensor. By providing an optical filter including an optical low-pass filter that cuts a component higher than the spatial frequency, an image pickup apparatus that can output an appropriate video signal without false colors or the like is provided.

  An image pickup apparatus according to a first aspect of the present invention is provided on the circuit board so as to cover an image pickup element mounted on a circuit board, an optical filter disposed on an optical path of light incident on the image pickup element, and the image pickup element. The image pickup apparatus includes a shield case that shields the image pickup device from electrical noise, and the shield case allows light to pass through the image pickup device and contacts the side surface of the optical filter to the image pickup device. An opening for positioning the optical filter is provided.

  In the present invention, the image pickup apparatus is provided with a shield case in which an optical filter is disposed on an optical path of light incident on the image pickup element and an electronic component such as the image pickup element mounted on the circuit board is shielded from electrical noise. Although it is necessary to form an opening through which light passes to the image sensor in the shield case, the side surface of the optical filter is brought into contact with the opening to position the optical filter. Thereby, when assembling the imaging device, it is not necessary to use a dedicated jig for positioning the optical filter, and the optical filter can be easily mounted on the imaging device.

  The image pickup apparatus according to the second invention is characterized in that the opening of the shield case has a shape that fits outside the optical filter.

  In the present invention, the shape of the opening of the shield case is a shape that is externally fitted to the optical filter. Thereby, when mounting an optical filter, the mounting position of an optical filter does not arise, but positioning of an optical filter can be performed reliably.

  An image pickup apparatus according to a third aspect is characterized in that the optical filter is adhered to the image pickup element.

  In the present invention, the optical filter is mounted by adhering and fixing the optical filter to the image sensor. Since the optical filter can be securely fixed after being positioned with respect to the image sensor, the mounting position of the optical filter does not shift due to external impact after the assembly of the imaging device is completed.

  An image pickup apparatus according to a fourth aspect is characterized in that the shield case has an edge portion of the opening bent toward the image pickup element.

  In the present invention, the edge portion of the opening of the shield case is bent toward the image sensor. As a result, the bent portion comes into contact with the side surface of the optical filter over a wide area, so that the optical filter can be easily positioned and can be positioned reliably.

  The image pickup apparatus according to a fifth aspect is characterized in that the optical filter includes an optical low-pass filter.

  In the present invention, the optical filter mounted on the imaging device includes an optical low-pass filter. The optical low-pass filter has a component higher than a specific spatial frequency determined from the pixel interval of the image sensor when the spatial period of the subject image formed on the image sensor by the lens is shorter than the pixel interval of the image sensor. Since the image is cut, the image sensor can output an appropriate video signal without false colors. In addition, when a color image sensor is mounted on an image pickup device, an unnecessary infrared ray contained in a large amount of sunlight may be cut off by mounting an optical filter including an infrared filter that cuts off an infrared ray. Is possible.

  According to the first aspect of the present invention, the optical filter is positioned by bringing the side surface of the optical filter into contact with the opening for allowing the light incident on the image sensor formed in the shield case to pass therethrough. When assembling the apparatus, since the positioning with respect to the image sensor can be performed easily and accurately without using a dedicated jig for positioning the optical filter, the assembling process of the imaging apparatus can be simplified. Cost can be reduced.

  Further, in the case of the second invention, the mounting shape of the optical filter is not displaced when mounting the optical filter by setting the shape of the opening of the shield case to a shape that is externally fitted to the optical filter. Since the optical filter can be positioned easily and reliably, the assembling process of the imaging device can be simplified, the assembling cost can be reduced, and the assembling accuracy can be increased.

  Further, in the case of the third invention, since the optical filter is bonded and fixed to the image sensor, the optical filter can be securely fixed after being positioned with respect to the image sensor. For example, there is no deviation in the mounting position of the optical filter. Therefore, the reliability of the imaging device can be increased.

  Further, in the case of the fourth invention, the edge portion of the opening of the shield case is bent toward the image sensor, so that the bent portion abuts on the side surface portion of the optical filter over a wide area, and the optical filter is positioned. Since it is easy and positioning can be performed reliably, the reliability of positioning of the optical filter in the assembly process of the imaging device can be increased.

  In the case of the fifth invention, when the optical filter including the optical low-pass filter is mounted, the spatial period of the subject image formed on the image sensor by the lens is shorter than the pixel interval of the image sensor. In addition, since a component higher than a specific spatial frequency determined from the pixel interval of the image sensor can be cut, the image sensor can output an appropriate video signal having no false color. In addition, when a color image sensor is mounted on the image pickup apparatus, unnecessary infrared rays contained in a large amount of sunlight can be cut by further mounting an optical filter including a filter that cuts infrared rays. Therefore, the image quality of the image captured by the imaging device can be improved.

  Hereinafter, the present invention will be specifically described with reference to the drawings showing embodiments thereof. FIG. 1 is a schematic cross-sectional view showing a configuration of an imaging apparatus according to the present invention. In the figure, reference numeral 1 denotes an image pickup device, in which a CCD chip 2 is enclosed in a package 3 having a substantially rectangular plate shape, a translucent face glass 4 is provided on one surface of the package 3, and a plurality of surfaces are provided on the opposite surface or side surface. A leg-shaped connection terminal 5 is provided. The CCD chip 2 has a large number of pixels that accumulate charges in accordance with received light in a matrix, and digital data corresponding to the amount of charges accumulated in each pixel can be acquired as image data. . The package 3 is formed of, for example, a synthetic resin, and has an opening (not shown) so as to expose the imaging surface of the CCD chip 2 to the outside. The face glass 4 is a glass plate for protecting the CCD chip 2 and is provided so as to cover the opening of the package 3 so that light can enter the CCD chip 2 through the face glass 4. . The connection terminal 5 is electrically connected to the CCD chip 2 in the package 3 so that it can exchange electrical signals, power supply power, and the like with the CCD chip 2.

  The imaging device has a substantially rectangular plate shape, and includes a circuit board 20 on which a plurality of electronic components (not shown) such as a DSP, a resistor, or a capacitor are mounted on one surface. The image pickup device 1 is mounted on one surface of the circuit board 20 by soldering the connection terminals 5. For example, the image pickup device 1 is configured to give image data acquired by imaging to a DSP mounted on the circuit board 20.

  The imaging apparatus also includes a shield case 30 for shielding the imaging element 1 and other electronic components mounted on the circuit board 20 from electrical noise. 2A and 2B are schematic views showing the configuration of the shield case 30 of the imaging apparatus according to the present invention, where FIG. 2A is a plan view and FIG. 2B is a side sectional view. The shield case 30 has a box shape having a top surface 31 and a peripheral surface 32 provided so as to surround the periphery of the top surface 31, and is formed by processing a metal plate. The top surface 31 of the shield case 30 has substantially the same rectangle as the circuit board 20, and the peripheral surface 32 is fitted on the peripheral edge of the circuit board 20, and the shield case 30 is attached to the circuit board 20. The shield case 30 is attached by fitting. On the inner side of the peripheral surface 32 of the shield case 30, there is provided a hook-like locking portion 35 that protrudes inward over the entire circumference so as to lock the circuit board 20 fitted in the shield case 30. . The shield case 30 can be positioned with respect to the circuit board 20 by the locking portion 35, and the shield case 30 is secured to the circuit board 20 using screws or the like (not shown) while the circuit board 20 is locked by the locking portion 35. It is supposed to be fixed to.

  A substantially rectangular opening 33 is formed on the top surface 31 of the shield case 30 at a position facing the image pickup device 1 mounted on the circuit board 20 when the shield case 30 is fixed to the circuit board 20. Further, the shield case 30 is formed with a bent portion 34 provided around the opening 33 so as to bend the edge portion of the opening 33 inward, that is, toward the image pickup device 1. The image pickup device 1 mounted on the circuit board 20 receives light collected by an optical system (not shown) of an image pickup apparatus constituted by a plurality of lenses and the like through an opening 33 of the shield case 30 and picks up an image. To do.

  The imaging apparatus also includes an optical filter 10 having a configuration in which an optical low-pass filter 11 and an infrared cut filter 12 each having a substantially rectangular plate shape are stacked. Since the optical low-pass filter 11 and the infrared cut filter 12 have substantially the same shape, the optical filter 10 has a substantially rectangular plate shape. The optical filter 10 has a shape that fits in the opening 33 of the shield case 30. The optical filter 10 is inserted into the opening 33 of the shield case 30 fixed to the circuit board 20 and is attached to the surface of the face glass 4 of the imaging device 1 using an adhesive in a state of being fitted into the opening 33. .

  For this reason, especially the position and shape of the opening 33 are accurately formed in the shield case 30, and when the shield case 30 is fixed to the circuit board 20, the position relative to the image pickup device 1 mounted on the circuit board 20. Further, errors such as orientation and the like are set within an error range such as position and orientation allowed when the optical low-pass filter 11 is mounted on the image sensor 1. Therefore, when the optical filter 10 is bonded to the image pickup device 1, it is not necessary to align the optical filter 10 with respect to the image pickup device 1, and the optical filter 10 is fitted into the opening 33 of the shield case 30. It is only necessary to bond them to the image sensor 1 together.

  3 and 4 are schematic views for explaining the assembly process of the imaging apparatus according to the present invention, and the assembly procedure is illustrated in time series from (A) to (D). In the assembly process of the imaging device, first, the imaging device 1 is fixed to the circuit board 20 (see FIG. 3A). The image sensor 1 is fixed by inserting the connection terminal 5 of the image sensor 1 into a through hole provided in the circuit board 20 or by connecting the connection terminal 5 of the image sensor 1 to a land portion provided on one surface of the circuit board 20. After the contact, the connection terminal 5 is soldered to one surface or the other surface of the circuit board 20.

  Next, the shield case 30 is fixed to the circuit board 20 on which the image sensor 1 is mounted (see FIG. 3B). At this time, the circuit board 20 is accommodated in the shield case 30 so that the surface on which the image pickup device 1 is mounted fits in the shield case 30 until the circuit board 20 is locked to the locking portion 35 of the shield case 30. To do. In a state where the shield case 30 is locked to the locking portion 35, the shield case 30 is fixed to the circuit board 20 using a screw or the like (not shown). The circuit board 20 and the shield case 30 may be fixed using other methods such as welding or adhesion.

  After fixing the circuit board 20 and the shield case 30, an adhesive 80 is dropped onto the approximate center of the face glass 4 of the image sensor 1 through the opening 33 formed in the shield case 30 (see FIG. 4C). As the adhesive 80, for example, an adhesive that is cured by irradiating ultraviolet rays, an adhesive that is cured by overheating, or the like can be used. However, an adhesive having translucency after curing is used.

  After the adhesive 80 is dropped on the image sensor 1, the optical filter 10 is mounted (see FIG. 4D). At this time, the optical filter 10 is inserted and fitted into the opening 33 of the shield case 30, and the optical filter 10 is pressed against the face glass 4 of the image pickup device 1 accommodated in the shield case 30. Adhesive 80 is filled between the optical filters 10. At this time, the position of the optical filter 10 is defined at the position of the opening 33, and the fitting of the optical filter 10 into the opening 33 is the positioning of the optical filter 10 with respect to the image sensor 1.

  After that, for example, treatment such as ultraviolet irradiation or heating is performed to cure the adhesive 80, and the imaging element 1 and the optical filter 10 are fixed. The imaging apparatus shown in FIG. 1 can be assembled by the above procedure, and it is not necessary to use a dedicated jig or the like for positioning the optical filter 10.

  In the imaging apparatus having the above-described configuration, the optical filter 10 is positioned with respect to the imaging element 1 by using the opening 33 of the shield case 30, so that a dedicated jig for positioning is not required, and imaging is performed. Since the assembly process of the apparatus can be simplified and the assembly cost can be reduced, there is an advantage that the imaging apparatus can be provided at low cost. In addition, by forming the opening 33 into a shape that fits into the optical filter 10, there is no risk of the optical filter 10 being displaced during assembly, and the optical filter 10 can be fixed with the adhesive 80 with high accuracy. In addition, by providing the bent portion 34 at the edge portion of the opening 33, when the optical filter 10 is inserted and fitted through the opening 33, the bent portion 34 abuts on the side surface portion of the optical filter 10, and the shield case 30. Since the contact area with the optical filter 10 is increased, the optical filter 10 can be easily mounted, and the possibility that the optical filter 10 is displaced can be more reliably reduced.

  In the present embodiment, the imaging device 1, the optical filter 10, the circuit board 20, and the shield case 30 are substantially rectangular, but the present invention is not limited to this, and other shapes may be used. In addition, the optical filter 10 is configured to stack the optical low-pass filter 11 and the infrared cut filter 12, but is not limited thereto, and may be configured by other filters. However, the present invention is suitable when the optical filter 10 includes a filter that requires accuracy of the mounting position with respect to the image sensor 1.

  In addition, the optical filter 10 is bonded to the image pickup device 1 using the adhesive 80, but the configuration is not limited to this. For example, the shield case 30 can hold the optical filter 10 firmly, and external shock can be applied. If there is no possibility that the fixing position of the shield case 30 is displaced due to, for example, a configuration in which adhesion is not performed. Alternatively, the optical filter 10 may be bonded to the shield case 30 in this case.

  In addition, the optical filter 10 is configured to fit into the opening 33 of the shield case 30, but the present invention is not limited to this. The opening 33 is formed larger than the optical filter 10, and at least one side of the opening 33 (however, the two intersecting each other) It is good also as a structure which can position the optical filter 10 with respect to the image pick-up element 1 by making the side part of the optical filter 10 contact | abut to the edge | side is preferable.

It is a typical sectional view showing the composition of the imaging device concerning the present invention. It is a schematic diagram which shows the structure of the shield case of the imaging device which concerns on this invention. It is a schematic diagram for demonstrating the assembly process of the imaging device which concerns on this invention. It is a schematic diagram for demonstrating the assembly process of the imaging device which concerns on this invention. It is typical sectional drawing which shows the structure of the conventional imaging device.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Image pick-up element 10 Optical filter 11 Optical low-pass filter 12 Infrared cut filter 20 Circuit board 30 Shield case 33 Opening 34 Bending part 80 Adhesive

Claims (5)

An image sensor mounted on the circuit board, an optical filter disposed on an optical path of light incident on the image sensor, and provided on the circuit board so as to cover the image sensor. In an imaging device comprising a shield case for shielding,
The image pickup apparatus, wherein the shield case has an opening that allows light to pass through the image sensor and contacts the side surface of the optical filter to position the optical filter with respect to the image sensor.   The imaging device according to claim 1, wherein the opening of the shield case is shaped to fit over the optical filter.   The imaging apparatus according to claim 1, wherein the optical filter is adhered to the imaging element.   The imaging apparatus according to any one of claims 1 to 3, wherein the shield case has an edge portion of the opening bent toward the imaging element.   The imaging device according to claim 1, wherein the optical filter includes an optical low-pass filter.

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