JP2006033138A - Small-sized imaging module - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a small-sized imaging module wherein the cost can be reduced by decreasing the number of components so as to bring efficiency to fitting and assembling processes and the downsizing and weight reduction of the entire module can be attained. <P>SOLUTION: The packaged small-sized imaging module 1 is formed by assembling a board 10 the holder 2 of which is mounted with a solid-state imaging element with a lens unit 20. The lens unit 20 comprises two lenses 22, 23 and a coating film 30 for reflecting an infrared ray is formed to a smoothed face 27 of the lens 23. Thus, it is possible for the lens 23 acting like an infrared ray reflection filter, and the number of components is reduced and the downsizing and weight reduction of the small-sized imaging module 1 can be attained. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a small-sized imaging module in which a solid-state imaging device and a lens that forms an image on the solid-state imaging device are packaged, and more particularly to a small-sized imaging module having infrared (IR) cut characteristics.

  In recent years, there has been an increasing demand for image sensors using solid-state image sensors such as CCDs and CMOSs mounted on portable computers, videophones, mobile phones, and the like. As this type of image sensor, for example, an image sensor mounted on a mobile phone or the like is desired to be miniaturized as much as possible. For example, as shown in Patent Document 1, an image sensor, a lens member, a filter, and a diaphragm By integrating parts such as members in a single package, the number of parts can be reduced and downsizing can be achieved, thereby enabling mounting on a mobile phone or the like.

  By the way, in a structure in which a single lens is arranged with respect to a solid-state imaging device such as a CCD or CMOS, spherical aberration or the like occurs, so it is difficult to improve optical performance. For this reason, in recent years, a small imaging module mounted on a mobile phone or the like has a plurality of lenses combined with an imaging element. In addition, a light receiving element on a solid-state imaging device such as a CCD has sensitivity in the human visible wavelength region (visible light region) and also in the near infrared region (700 nm to 1200 nm). Because the sensitivity of the light receiving element in the near infrared region greatly affects the brightness adjustment and color balance adjustment when processing the received image, the near infrared light is cut off in a small imaging module. An infrared cut filter for mounting is assembled into a holder together with a lens unit and packaged.

JP 2003-289459 A

  In the small imaging module shown in Patent Document 1, since the infrared cut filter is incorporated as a separate component in the holder together with the lens unit, not only the number of components increases, but also the assembly work process of these components increases. In addition to being inferior in workability, since the infrared cut filter is a single component, it has a certain thickness and is disadvantageous for miniaturization by the space for providing the infrared cut filter.

  Therefore, the present invention aims to reduce costs by reducing the number of parts and improving the efficiency of the assembly and assembling process, and by making the lens unit have an infrared cut characteristic, the entire device can be reduced in size and weight. An object is to provide an imaging module.

  According to a first aspect of the present invention, there is provided a compact image pickup module including a substrate on which a solid-state image pickup device is mounted, a lens unit including a plurality of lenses for forming a subject image on the solid-state image pickup device, and the substrate and the lens unit packaged In the small imaging module including the holder, a coating film having infrared cut characteristics is formed on at least one of the plurality of lenses.

  With the above configuration, it is possible to correct spherical aberration and curvature of field by incorporating a lens unit composed of a plurality of lenses into the holder, and in particular during temperature changes that are likely to be problematic when the lens is made of a resin material. The effects of refractive index changes and lens shape changes can be eliminated by combining a plurality of lenses, and fluctuations in image point position due to temperature changes can be kept small. In addition, by forming a coating film that reflects infrared rays on a single lens incorporated in a lens barrel for the purpose of correcting spherical aberration and curvature of field, charges are saturated in an environment where there is a lot of infrared rays, such as outdoors. Can be prevented from becoming white.

  The small image pickup module according to claim 2 of the present invention is the small image pickup module according to claim 1, wherein the lens unit includes a lens body in which at least two resin lenses are combined, and the lens body and the solid-state image sensor. A coating film having an infrared cut characteristic is formed on a single resin lens including a single resin lens interposed therebetween.

  With the above configuration, by forming a coating film that reflects infrared rays on a resin lens incorporated in the lens barrel for the purpose of correcting spherical aberration and curvature of field, the charge is saturated in an environment where there is a lot of infrared rays such as outdoors. Can be prevented from becoming white.

  The small image pickup module according to claim 3 of the present invention is the small image pickup module according to claim 1, wherein the lens unit includes a lens body in which at least two resin lenses are combined, and the lens body and the solid-state image sensor. It is characterized in that it includes one glass lens interposed therebetween, and a coating film having infrared cut characteristics is formed on the glass lens.

  With the above configuration, a coating film that reflects infrared rays is formed on a glass lens incorporated in a lens barrel for the purpose of correcting spherical aberration and curvature of field. Can be prevented from becoming white.

  A small imaging module according to a fourth aspect of the present invention is the small imaging module according to any one of the first to third aspects, wherein one surface of the lens having the infrared cut characteristic is a flat smooth surface. The coating film is formed on the surface of the film.

  With the above configuration, a coating film having a uniform thickness can be formed on the smooth surface of the lens.

  A small imaging module according to a fifth aspect of the present invention is the small imaging module according to any one of the first to fourth aspects, wherein a lens barrel for holding the lens unit is provided, and the lens barrel is disposed on the holder. The lens unit is assembled so as to be movable in the optical axis direction of the lens unit.

  With the above configuration, the distance between the solid-state image sensor and the lens unit can be finely adjusted, and the light receiving surface of the image sensor can be accurately set at the in-focus position of the lens unit.

  According to the small image pickup module of the present invention, a substrate on which a solid-state image sensor is mounted, a lens unit including a plurality of lenses for forming a subject image on the solid-state image sensor, and the substrate and the lens unit. In a small imaging module having a holder for packaging, a coating film having infrared cut characteristics is formed on at least one of the plurality of lenses. It can also be used as an infrared reflection filter, and there is no need to provide a dedicated infrared reflection filter. For this reason, the number of parts can be reduced, and as a result, the assembly process is reduced and the cost is reduced. In addition, a space for installing a dedicated infrared reflection filter is not required, and the entire apparatus can be reduced in size and weight.

  According to a small imaging module according to claim 2 of the present invention, in the small imaging module according to claim 1, the lens unit is a lens body in which at least two resin lenses are combined, and the lens body and the solid-state imaging device. Since a single resin lens is interposed between the two and a coating film having infrared cut characteristics is formed on the single resin lens, the installation space for the dedicated infrared reflection filter is not required, and the entire apparatus When the infrared reflective film is formed on the glass substrate, it is possible to cut the continuous glass substrate into a predetermined shape, resulting in low production efficiency and high manufacturing cost. The resin lens that forms can be easily molded by injection molding, and the molding process is easy and the production efficiency is improved. From being, it is possible to greatly reduce the manufacturing cost.

  According to a small imaging module according to claim 3 of the present invention, in the small imaging module according to claim 1, the lens unit is a lens body in which at least two resin lenses are combined, and the lens body and the solid-state imaging device. It is possible to use the glass lens incorporated in the holder as an infrared reflection filter because the glass lens is formed with a coating film having infrared cut characteristics. It is not necessary to provide a dedicated infrared reflection filter.

  According to a small imaging module according to a fourth aspect of the present invention, in the small imaging module according to any one of the first to third aspects, one side of the lens having the infrared cut characteristic is a flat smooth surface, Since the coating film is formed on the surface of the smooth surface, the coating film can be formed with a uniform thickness on the smooth surface of the lens, and the coating film can effectively prevent the transmission of external lines. .

  According to the small imaging module according to claim 5 of the present invention, in the small imaging module according to any one of claims 1 to 4, a lens barrel for holding the lens unit is provided, Since the holder is assembled so as to be movable in the optical axis direction of the lens unit, the distance between the solid-state imaging device and the lens unit lens can be easily finely adjusted.

  Embodiments of the present invention will be described based on examples with reference to the drawings. FIG. 1 shows a cross-sectional view of a small imaging module. As shown in the figure, the small imaging module 1 is packaged by assembling a holder 10 with a substrate 10 and a lens unit 20.

  The holder 2 has a cylindrical portion 6 having an internal thread 5 on the inner peripheral surface and a box-shaped case 7 integrally formed at the lower portion of the cylindrical portion 6 and is integrally formed of synthetic resin. A barrel 8 for fixing a lens unit 20 composed of a plurality of lenses, which will be described later, is assembled to the cylindrical portion 6, and a male screw that is screwed onto the outer peripheral surface of the barrel 8 with the female screw 5 of the cylindrical portion 6. 9 is formed. On the other hand, on the lower surface of the case 7, the substrate 10 on which the semiconductor chip 11 incorporating a solid-state image sensor such as a MOS transistor such as a photodiode or a CCD element is mounted so as to cover the opening of the case 7 is fixed. The distance between the solid-state imaging device and the lens unit 20 is finely adjusted by adjusting the screwing amount of the lens barrel 8 screwed to the female screw 5 of the cylindrical portion 6, and then an adhesive or the like is adjusted. Thus, the holder 2 and the lens barrel 8 are integrally fixed.

  A lens holder 20A for pressing the lens unit 20 is formed on the upper surface side of the lens barrel 8, and an aperture portion 21 having an opening serving as an optical path is formed in the lens holder 20A. The lens unit 20 assembled to the lens barrel 8 is composed of two lenses 22 and 23, and these two lenses 22 and 23 are positioned in the optical axis direction with respect to the lens barrel 8 by spacers 24 and 25. Has been. The lenses 22 and 23 are made of, for example, glass or resin (material is not particularly limited), and the lens 22 disposed on the upper side is positioned by the lens retainer 20A. The lens 22 has convex lens portions 22A and 22B formed on both surfaces thereof, and the lens 23 disposed below the lens 22 has a smooth surface 27 having a flat surface on one side and a convex lens portion 28 formed on the other surface. A coating film 30 is formed on the smooth surface 27 by vapor deposition or the like to reflect infrared rays and prevent transmission of infrared rays. The smooth surface 27 of the lens 23 forming the coating film 30 is shown as being mounted toward the semiconductor chip 11 side in which the solid-state imaging device is incorporated, as shown in FIG. It is also possible to form the lens 22 side. Thus, by incorporating a plurality of lenses 22 and 23 in the lens barrel 8 as the lens unit 20, it is possible to correct spherical aberration and field curvature. In particular, when the lenses 22 and 23 are made of a resin material, the influence of a change in refractive index or a change in lens shape, which is likely to be a problem, can be eliminated by combining the plurality of lenses 22 and 23. The fluctuation of the image point position due to can be suppressed small. Then, in this way, a plurality of lenses 22 and 23 are incorporated in the lens barrel 8 for the purpose of correcting spherical aberration and field curvature, and a coating film 30 is formed on one of the lenses 23. It prevents the image from becoming white due to the saturation of the charge in an environment with a lot of infrared rays such as outdoors.

  Thus, by incorporating a plurality of lenses 22 and 23 in the lens barrel 8 as the lens unit 20, it is possible to correct spherical aberration and field curvature. In particular, when the lenses 22 and 23 are made of a resin material, the influence of the refractive index change and the lens shape change at the time of temperature change, which is likely to be a problem, can be eliminated by combining the plurality of resin lenses 22 and 23. Variations in image point position due to changes can be kept small. In this way, a plurality of lenses 22 and 23 are incorporated in the lens barrel 8 for the purpose of correcting spherical aberration and curvature of field, and the coating film 30 is formed on the one lens 23, thereby infrared rays such as outdoors. This prevents the image from becoming saturated due to the saturation of the charge in an environment where there are many images.

  As described above, by forming the coating film 30 that reflects infrared rays and prevents the transmission of infrared rays on one lens 23 constituting the lens unit 20, the lens 23 can be used also as an infrared reflection filter. There is no need to provide a dedicated infrared reflection filter. For this reason, the number of parts can be reduced, and as a result, the assembly process is reduced and the cost is reduced. In addition, a space for installing a dedicated infrared reflection filter is not required, and the entire apparatus can be reduced in size and weight. In addition, when an infrared reflective film is formed on a glass substrate as in the past, the continuous glass substrate is cut into a predetermined shape, so that the production efficiency is low and the manufacturing cost is also high. However, if the lens 23 is integrally molded with a resin and the coating film 30 is formed on the resin lens 23, the lens 23 can be easily molded by injection molding, the molding process is easy, and the production efficiency is excellent. As a result, the manufacturing cost can be greatly reduced. Further, when forming the coating film 30 on the lens 23, when the coating film 30 is formed on the convex lens portion 28 side, the coating film 30 gradually becomes thicker toward the top of the convex lens portion 28, and the coating film 30 is not thick. Although the coating film 30 is formed on the flat smooth surface 27 formed on one surface of the single lens 23, the coating film 30 can be formed with a uniform thickness. As a result, infrared rays are effectively reflected by the coating film 30 so that the characteristics of the image are not changed or deteriorated. By incorporating the lens unit 20 including the lens 23 having such infrared cut characteristics into the lens barrel 8, it is possible to correct spherical aberration and curvature of field. In particular, the effects of refractive index change and lens shape change at the time of temperature change, which can be a problem when the lens is made of a resin material, can be eliminated by combining a plurality of resin lenses 22 and 23. Therefore, the fluctuation of the image point position due to the temperature change can be suppressed to a small extent, and the coating film 30 formed on the lens 23 prevents the image from becoming saturated due to the saturation of electric charge in an environment with a lot of infrared rays such as outdoors. it can. Further, by screwing the male threaded portion 9 of the lens barrel 8 incorporating the lens unit 20 into the female screw 5 of the cylindrical portion 6 of the holder 6, the lens barrel 8 incorporating the lens unit 20 is fixed to the holder 6 with respect to the holder 6. Since the resin lens is assembled so as to be movable in the optical axis direction, the distance between the solid-state imaging device and the lens unit 20 can be easily adjusted by adjusting the screwing amount of the lens barrel 8.

  FIG. 2 shows a second embodiment of the present invention. Parts having the same functions as those of the first embodiment are denoted by the same reference numerals, and only different parts will be described. In this embodiment, the lens unit 20 includes a lens body 34 in which two resin lenses 32 and 33 are overlapped with a diaphragm plate 31 interposed therebetween, and a spacer 35 between the lens body 34 and the substrate 10. It consists of a single lens 36 that is made of glass or resin and that is interposed therebetween. The aperture plate 31 is formed with an opening 31a serving as an optical path, and the two resin lenses 32 and 33 are overlapped with the aperture plate 31 interposed therebetween. The single lens 36 has a flat smooth surface 37 on one surface, and a convex lens portion 38 is formed on the other surface. The smooth surface 37 reflects infrared rays by vapor deposition or the like to prevent infrared transmission. A coating film 30 is formed. The smooth surface 37 of the single lens 36 that forms the coating film 30 faces the lens body 34 side as shown in FIG. 2, but the smooth surface 37 faces the semiconductor chip 11 side as shown in FIG. It is also possible to attach it. Thus, by incorporating a plurality of resin lenses 32, 33, and 36 into the lens barrel 8 as the lens unit 20, it is possible to correct spherical aberration and field curvature. In particular, the effects of the refractive index change and the lens shape change at the time of temperature change, which tend to be a problem when the lenses 32, 33, and 36 are made of a resin material, are eliminated by combining a plurality of resin lenses 32, 33, and 36. Thus, fluctuations in the image point position due to temperature changes can be suppressed to a small level. In this way, the coating film 30 is formed on the single lens 36 incorporated in the lens barrel 8 for the purpose of correcting the spherical aberration and the curvature of field, and the coating film 30 charges in an environment with a lot of infrared rays such as outdoors. Is saturated and the image is prevented from becoming white.

  As described above, by forming the coating film 30 that reflects infrared rays and prevents the transmission of infrared rays on the single lens 36 that constitutes a part of the lens unit 20, the lenses 36 are made infrared rays as in the first embodiment. It can also be used as a reflection filter, and there is no need to provide a dedicated infrared reflection filter. For this reason, the number of parts can be reduced, and as a result, the assembly process is reduced and the cost is reduced. In addition, a space for installing a dedicated infrared reflection filter is not required, and the entire apparatus can be reduced in size and weight. Further, by forming the coating film 30 on the flat smooth surface 37 formed on the single lens 36, the coating film 30 can be formed with a uniform thickness, and the coating film 30 formed on the lens 36 allows outdoor use. It is possible to prevent the image from becoming white due to the saturation of the charge in an environment with a lot of infrared rays.

  As mentioned above, although the Example of this invention was explained in full detail, this invention is not limited to the said Example, A various deformation | transformation implementation is possible within the range of the summary of this invention. For example, the number and shape of the lenses constituting the lens unit, the shape of the holder, the mounting structure of each component, and the like may be selected as appropriate.

1 is an overall cross-sectional view of a small image pickup module showing a first embodiment of the present invention. It is a whole sectional view of a small image pick-up module showing the 2nd example of the present invention. FIG. 2 is an overall cross-sectional view of a small imaging module showing a state where a lens having infrared reflection characteristics is inverted and assembled.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Small imaging module 2 Holder 10 Board | substrate 11 Semiconductor chip (solid-state image sensor)
20 Lens unit 22, 23, 32, 33, 36 Lens 34 Lens body 27, 37 Smooth surface 30 Coating film

Claims (5)

  A compact imaging module comprising: a substrate on which a solid-state imaging device is mounted; a lens unit including a plurality of lenses that forms a subject image on the solid-state imaging device; and a holder that packages the substrate and the lens unit. A small imaging module, wherein a coating film having infrared cut characteristics is formed on at least one of the lenses.   The lens unit includes a lens body in which at least two resin lenses are combined, and one resin lens interposed between the lens body and the solid-state imaging device, and the single resin lens has infrared cut characteristics. The small imaging module according to claim 1, wherein a coating film is formed.   The lens unit includes a lens body in which at least two resin lenses are combined, and one glass lens interposed between the lens body and the solid-state imaging device, and the glass lens has an infrared cut characteristic. The small image pickup module according to claim 1, wherein:   The small-sized imaging module according to any one of claims 1 to 3, wherein one surface of the lens having infrared cut characteristics is a flat smooth surface, and the coating film is formed on the surface of the smooth surface. .   The lens barrel for holding the lens unit is provided, and the lens barrel is assembled to the holder so as to be movable in the optical axis direction of the lens unit. The small imaging module of any one of Claims.

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