JP2011248043A - Manufacturing method of imaging device and imaging device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a manufacturing method of an imaging device which reduces an occurrence of one-sided defocusing and displays an excellent shot image.SOLUTION: A manufacturing method of an imaging device comprises: a lens group including indexes formed on at least two efficient optical surfaces thereof; a mirror frame holding the lens group; and an image element photoelectrically converting a subject image formed by the lens group. The manufacturing method of the imaging device includes the steps of: incorporating the lens group in the mirror frame based on the indexes; matching, based on one index formed on the lens group, a perpendicular line at a center position of an effective pixel region of the image element with an optical axis position on the efficient optical surface where the index is formed; and matching, based on the other index formed on the lens group, the perpendicular line with the optical axis position on the efficient optical surface where the index is formed.

Description

  The present invention relates to a manufacturing method of an imaging device having a lens group and an imaging device that photoelectrically converts a subject image formed by the lens group, and an imaging device manufactured by the manufacturing method.

  Conventionally, a method has been known in which a minute convex portion or concave portion is formed as an index for positioning in an effective optical surface of an optical element, and the optical element is positioned by using the index when incorporated in a lens frame. ing.

  Furthermore, there is known an apparatus that aligns an image pickup element and an optical element based on an index formed on the optical element and a pixel pattern of the image pickup element (see, for example, Patent Document 1).

JP 2006-268015 A

  However, when an image pickup device is manufactured by combining an image pickup element and a lens group incorporated in a lens frame, the center position of the effective pixel region of the image pickup element and the lens center on which the index is formed are viewed from the optical axis direction. It cannot be said that the positional relationship between the lens group and the image sensor surface is determined only by matching.

  FIG. 7 is a schematic diagram showing alignment based on the index formed on the conventional optical element and the pixel pattern of the image sensor.

  The lens group shown in the figure has a four-lens configuration of a first lens L1 to a fourth lens L4, and F is an infrared light cut filter. When the first lens L1 to the fourth lens L4 are incorporated in the lens frame 55, the index S1 formed on the optical axis of the first lens L1 and the index S4 formed on the optical axis of the fourth lens L4 are used. The optical axis is adjusted. Reference numeral 51 denotes an imaging device having an effective pixel area 51a, which is mounted on the support substrate 52a.

  As shown in FIG. 7, the normal C of the effective pixel region 51a of the image sensor 51 and the index S1 of the lens group incorporated in the lens frame 55 and aligned with the optical axis coincide with each other using the microscope K. When adjusted in this way, there are the following problems.

For example, if there is an error in the height dimension of the attachment surface 55t ₁ and 55t ₂ and the substrate 52a in contact with the lens frame 55, as shown, the optical axis O of the lens group shown by the solid line, the effective pixel region shown by the one-dot chain line The state is inclined with respect to the perpendicular C at the center position of 51a in accordance with the dimensional error (shown in a state tilted by an angle θ).

  That is, in order to maximize the performance of the lens group, not only the horizontal shift (shift) between the center position of the effective pixel area and the optical axis of the lens group, but also the tilt of the optical axis with respect to the normal of the effective pixel area surface ( (Tilt) also needs to be adjusted and matched. In particular, when an imaging device is manufactured by combining a member on which an imaging element is placed and a lens frame in which a lens group is incorporated, the occurrence of tilt is unavoidable due to component errors on the mounting surface, and so on. Blur becomes a problem.

  However, in the method of manufacturing the optical device described in Patent Document 1, there is no adjustment of the tilt only by positioning in the horizontal direction, and there is a problem in that one-sided blur or the like occurs at the periphery of the captured image.

  In view of the above problems, an object of the present invention is to provide a method of manufacturing an imaging device that can suppress the occurrence of one-sided blur and obtain a good captured image.

  The above object is achieved by the following configuration.

  (1) An imaging apparatus having a lens group in which an index is formed on at least two effective optical surfaces, a lens frame that holds the lens group, and an imaging element that photoelectrically converts a subject image formed by the lens group. In the manufacturing method, the step of incorporating the lens group into the lens frame based on the index, the perpendicular of the center position of the effective pixel area of the image sensor, and one index formed on the lens group, Aligning the optical axis position of the formed effective optical surface and aligning the optical axis position of the effective optical surface on which the index is formed based on the perpendicular and the other index formed on the lens group. And a method of manufacturing the imaging device.

  (2) The method for manufacturing an imaging device according to (1), wherein the index is formed on an optical axis of an effective optical surface.

  (3) The method according to (1) or (2), wherein the index is formed on a surface closest to the object side and a surface closest to the image side of the lens group.

  (4) An image pickup apparatus manufactured by the method for manufacturing an image pickup apparatus according to any one of (1) to (3).

  According to the present invention, it is possible to provide a method of manufacturing an imaging device that can suppress the occurrence of one-sided blur and obtain a good captured image.

It is sectional drawing of the imaging device manufactured by the manufacturing method of the imaging device of this invention. It is a flowchart which shows the manufacture order of the imaging device which concerns on this Embodiment. It is a schematic diagram which shows the process of step S101. It is a schematic diagram which shows the process of step S102. It is a schematic diagram which shows the process of step S103, S105. It is sectional drawing of the imaging device formed by incorporating a mirror frame in a housing | casing and couple | bonding a housing | casing and a board | substrate. It is a schematic diagram which shows the alignment based on the parameter | index formed in the conventional optical element, and the pixel pattern of an image pick-up element.

  Hereinafter, the present invention will be described with reference to embodiments, but the present invention is not limited thereto.

  FIG. 1 is a cross-sectional view of an imaging device 50 manufactured by the manufacturing method of the imaging device of the present invention.

  The lens group unit 10 includes a first lens L1, a second lens L2, a third lens L3, a fourth lens L4, a lens frame 55 that holds the first lens L1 to the fourth lens L4, an aperture stop S, red The external light cut filter F is used. An index S1 is formed on the optical axis position of the object side surface of the first lens L1, and an index S4 is formed on the optical axis position of the image side surface of the fourth lens L4. The index is obtained by transferring very minute convex portions or concave portions formed on the mold.

  An imaging element 51, which is a CMOS type image sensor, has an effective pixel area 51a as a light receiving portion in which pixels (photoelectric conversion elements) are two-dimensionally arranged on the light receiving side surface, and a signal is provided around the pixel area 51a. A processing circuit 51b is formed. The signal processing circuit 51b includes a driving circuit unit that sequentially drives each pixel to obtain a signal charge, an A / D conversion unit that converts each signal charge into a digital signal, and a signal that forms an image signal output using the digital signal. It consists of a processing unit and the like. The image sensor 51 may be a CCD type image sensor.

  A large number of pads (not shown) are provided in the vicinity of the outer edge of the light receiving side surface of the image sensor 51, and are connected to the support substrate 52 a via bonding wires W.

  One end of the substrate 52 is connected to a hard support substrate 52a that supports the image sensor 51 and the lens frame 55 on one surface, and the other surface (surface opposite to the image sensor 51) of the support substrate 52a. It is comprised with the flexible printed circuit board 52b. The support substrate 52a is provided with a large number of signal transmission pads on both the front and back surfaces, and is connected to the imaging device 51 via bonding wires W on one surface and to the flexible printed circuit board 52b on the other surface. .

  As shown in FIG. 1, the flexible printed circuit board 52b has one end connected to the support substrate 52a, and the support substrate 52a and an external circuit (not shown) via an external connection terminal (not shown) provided at the other end. For example, it is connected to a control circuit of a host device on which the image pickup apparatus is mounted, and receives a voltage and a clock signal for driving the image pickup device 51 from an external circuit, and outputs a digital YUV signal to the external circuit. It is possible to do.

  Although not shown, a fixed diaphragm for cutting unnecessary light may be disposed between the lenses L1 to L4.

Lens frame 55 of the image pickup apparatus 50 shown in FIG. 1, one a mounting surface 55t ₁ of abutting the support substrate 52a, on the other mounting surface height of 55t ₂ are different (Fig. 1, the mounting surface 55t ₂ is short). However, according to the manufacturing method of the imaging device of the present invention, even if the height dimension of the mounting surface is different, the perpendicular C of the center position of the effective pixel region 51a of the imaging device 51 and the optical axis of the lens group unit 10 It can be manufactured in a state in which O is substantially matched. Thereby, it is possible to obtain an imaging device that can suppress the occurrence of one-sided blur and obtain a good image.

  Hereinafter, the manufacturing method of the imaging device according to the present invention will be described.

  FIG. 2 is a flowchart showing the manufacturing sequence of the imaging apparatus according to the present embodiment. Hereinafter, it demonstrates according to a flow.

  In the flow shown in FIG. 2, a lens group unit 10 is created by incorporating a lens in the lens frame 55 using an index formed on the lens surface (step S101).

  FIG. 3 is a schematic diagram showing the process of step S101. 3A shows a state in which the first lens L1 is incorporated in the lens frame 55, and FIG. 3B shows a state in which up to the fourth lens L4 is incorporated in the lens frame 55.

  In step S101, first, as shown in FIG. 3A, the first lens L1 is assembled into the lens frame 55 and bonded. Next, the microscope K or the stage 60 is moved in the Z direction to focus the microscope K on the index S1 formed on the first lens L1. Next, the microscope K or the lens frame 55 is moved in the X and Y directions, and the index S1 is matched with the center position of the scale SK in the field of view of the microscope K.

  In this state, the microscope K or the stage 60 is moved in the Z direction, and the second lens L2 and the third lens L3 are incorporated into the lens frame 55 and bonded.

  Further, as shown in FIG. 3B, the fourth lens L4 is incorporated in the lens frame 55, the microscope K or the stage 60 is moved in the Z direction, and the index S4 formed on the fourth lens L4 is placed on the microscope S4. Adjust the focus of K. Next, the fourth lens L4 is moved in the X and Y directions within the lens frame 55 so that the index S4 is aligned with the center position of the scale SK within the field of view of the microscope K, and then bonded and fixed with an adhesive (not shown). Thereafter, the infrared light cut filter F is assembled and the creation of the lens group unit 10 is completed.

  In this example, an example in which indexes are formed on the first lens L1 and the fourth lens L4 is described. However, an index is formed on all the lenses, and each time a lens is incorporated, the field of view of the microscope K is reduced. The index may be matched with the center position of the scale SK. Further, in this example, a description is given by taking a lens group having four lenses as an example, but the number of lenses in the lens group is not limited to this, and any number may be used.

  Returning to the flow of FIG. 2, the substrate 52 on which the image sensor 51 is mounted is placed on the stage 60 so that the surface of the effective pixel region 51 a of the image sensor 51 and the optical axis of the microscope K are accurately perpendicular. After the adjustment, the perpendicular of the center position of the effective pixel area 51a is matched with one index formed on the lens constituting the lens group unit 10 created in step S101 (step S102).

  FIG. 4 is a schematic diagram showing the process of step S102. 4A shows a state in which the center position of the effective pixel region 51a of the image sensor 51 is matched with the center position of the scale SK in the field of view of the microscope K, and FIG. 4B shows the center of the effective pixel region 51a. The vertical line of the position and the index S1 formed on the first lens L1 of the lens group unit 10 created in step S101 are shown matched.

  In step S102, first, the substrate 52 on which the image sensor 51 is mounted is placed on the stage 60, and the surface of the effective pixel region 51a of the image sensor and the optical axis of the microscope K are adjusted to be vertical.

  Specifically, for example, the microscope K is focused on any three end points of the effective pixel region 51a. The inclination of the surface of the effective pixel region 51a with respect to the optical axis of the microscope K can be determined from the position in the optical axis direction (Z direction) of each microscope K when the three end points are focused. Next, in correspondence with this inclination, the angle stage 60 is rotated about the X and Y axes, and the surface of the effective pixel region 51a and the optical axis of the microscope K are adjusted to be vertical.

  Next, the corners of the effective pixel region 51a and the center position of the scale SK are matched, and the stage 60 is rotated around the Z axis to align the long side direction and the short side direction of the scale SK and the effective pixel region 51a. Thereafter, the microscope K or the stage 60 is moved by a predetermined amount in the X direction and a predetermined amount in the Y direction. As a result, as shown in FIG. 4A, the center position of the effective pixel region 51a of the image sensor 51 and the field of view of the microscope K in the state where the surface of the effective pixel region 51a and the optical axis of the microscope K are perpendicular to each other. The center position of the scale SK is matched.

  Next, as shown in FIG. 4B, the microscope K is moved in the Z direction, the lens group unit 10 created in step S <b> 101 is carried using the jig 61, and the microscope K and the image sensor 51 are interposed. Move. Further, the microscope K is focused on the index S1 formed on the first lens L1 of the lens group unit 10, and the jig for holding the lens group unit 10 is moved in the X and Y directions. The index S1 is matched with the center position of the scale SK.

At this time, if the height dimensions of the mounting surfaces 55t ₁ and 55t ₂ of the lens frame 55 to the support substrate 52a are different, the lens group unit 10 has already tilted when it is placed in another place. As shown in the figure, it is also tilted when carried by the jig 61 (in the figure, it is exaggerated as the inclination θ). For this reason, the optical axis O of the lens group in the lens group unit 10 is inclined with respect to the perpendicular C at the center position of the effective pixel region 51a indicated by the alternate long and short dash line.

  Note that the jig 61 is preferably supported at three points at intervals of 120 degrees when the lens frame 55 is circular, and is supported at four points at intervals of 90 degrees when the frame 61 is rectangular. The position of the jig 61 that supports the lens frame 55 is preferably in the vicinity of a plane perpendicular to the optical axis O passing through the index S1 of the first lens L1.

  Returning to the flow of FIG. 2, the perpendicular C of the center position of the effective pixel region 51a of the image sensor 51 and the index S4 formed on the fourth lens L4 of the lens group unit 10 are matched (step S103). Thereby, the perpendicular C at the center position of the effective pixel area 51a coincides with the index S1 formed on the first lens L1 and the index S4 formed on the fourth lens L4 of the lens group unit 10, and the perpendicular C and the optical axis. O can be matched.

Next, the jig carrying the stage 60 or the lens group unit 10 in this state is moved in the Z direction until at least one mounting surface (the mounting surface 55t _{1 in} this example) of the lens frame 55 and the support substrate 52a come into contact with each other. (Step S104). Further, in a condition in which the mounting surface 55t ₁ and the supporting substrate 52a is in contact, the contact portion of the supporting substrate 52a and the mounting surface 55t ₁ and the adhesive B is applied between the supporting substrate 52a and the mounting surface 55t _2, temporarily cured (Step S105).

FIG. 5 is a schematic diagram showing steps S103 and S105. FIG. 5A shows a state in which the perpendicular C of the center position of the effective pixel region 51a of the image sensor 51 and the index S4 formed on the fourth lens L4 of the lens group unit 10 are matched in step S103. Yes. 5 (b) is the step S105, the contact portion of the supporting substrate 52a and the mounting surface 55t ₁ and the adhesive B is applied between the supporting substrate 52a and the mounting surface 55t _2, shows a state of being temporarily cured .

  In step S103, the microscope K is moved in the Z direction so that the index S4 of the fourth lens L4 is in focus with the jig 61 holding the lens group unit 10. Thereafter, using a jig (not shown), the lower side of the lens frame 55 is pressed from the side (arrow shown) in order to match the index S4 with the center position of the scale SK in the field of view of the microscope K. The lens group unit 10 is rotated while being held in the state shown in FIG. 5A. At this time, since the jig holds the lens frame 55 in the vicinity of the index S1, the index S1 hardly moves. Thereby, the perpendicular C at the center position of the effective pixel area 51a matches the index S1 formed on the first lens L1 of the lens group unit 10 and the index S4 formed on the fourth lens L4, that is, the perpendicular C and the optical axis. O matches.

In step S104, at least one mounting surface of the lens frame 55 is brought into contact with the support substrate 52a, and in this state, adhesive B is applied and temporarily cured as shown in FIG. 5B. Let That is, when there is a dimensional difference between the attachment surfaces 55t ₁ and 55t ₂ , the difference is interpolated by the adhesive B.

  Note that it is preferable to use an ultraviolet curable adhesive that has a high viscosity and does not shrink or is small after curing. Moreover, temporary hardening means the state hardened to such an extent that it does not deform | transform even if a little external force is applied.

  Returning to the flow of FIG. 2, after the adhesive B is temporarily cured, the jig 61 is removed, the imaging device 50 is removed from the stage 60, and the adhesive B is fully cured (step S106). As a result, it is possible to obtain the imaging device 50 that eliminates the tilt (tilt) of the optical axis due to the dimensional error of the lens frame 55 as shown in FIG.

  The index only needs to be formed on at least two effective optical surfaces in the lens group. However, as described above, the index is preferably formed on the most object side surface and the most image side surface. By forming indexes on the two surfaces that are farthest in this way, the matching accuracy between the perpendicular C and the optical axis O can be improved.

  In addition, the index is preferably formed on the optical axis, but is not limited to this, as long as it is visible in the field of view of the microscope in the arrangement state of each element as described above, the optically effective surface It may be formed in the peripheral part of. In this case, it is only necessary to be incorporated into a lens frame so that the relative positional relationship between the optical axis and the index becomes clear. In addition, the indicator need not have a shape that is intentionally formed on the mold, and it should be formed with reproducibility without individual differences such as scratches that are not intentionally formed on the mold. That's fine.

  Further, the present application is not only for directly coupling the lens frame incorporating the lens group as described above and the support substrate, but also incorporating the lens frame incorporating the lens group in the housing, The present invention can also be applied to an imaging device assembled by combining.

  FIG. 6 is a cross-sectional view of an imaging device 50 in which a lens frame is incorporated in a housing and the housing and the substrate are combined.

An imaging apparatus 50 shown in FIG. 6 is obtained by assembling the lens group unit 10 created by the method described with reference to FIG. 3 to a housing 53 and combining the mounting surfaces 53t ₁ and 53t ₂ of the housing 53 with a support substrate 52a. It is.

In the case of such a configuration, the housing 53 to which the lens group unit 10 is assembled is held by a jig, and the method similar to that shown in FIGS. The dimensional difference between the surfaces 53t ₁ and 53t ₂ is interpolated by the adhesive B, and the imaging device 50 in which the tilt (tilt) of the optical axis is eliminated can be obtained.

  In the present application, the term “match” in the above description does not only mean that the word matches exactly, but also includes matching so as to be within a predetermined allowable range.

10 lens group unit 50 imaging device 51 imaging device 51a effective pixel region 51b the signal processing circuit 52 board 52a supporting substrate 52b flexible printed board 53 housing 53t _1, 53t ₂ mounting surface 55 lens frame 55t _1, 55t ₂ attachment surface 60 Stage 61 Jig L1 1st lens L2 2nd lens L3 3rd lens L4 4th lens B Adhesive F Infrared light cut filter K Microscope O Optical axis S Aperture stop SK Scale S1, S4 Index

Claims (4)

A lens group having an index formed on at least two effective optical surfaces;
A lens frame for holding the lens group;
In a manufacturing method of an imaging device having an imaging element that photoelectrically converts a subject image formed by the lens group,
Incorporating the lens group into the lens frame based on the index;
Aligning the perpendicular of the center position of the effective pixel region of the image sensor and the optical axis position of the effective optical surface on which the index is formed based on one index formed on the lens group;
And a step of aligning the perpendicular and the optical axis position of the effective optical surface on which the index is formed based on the other index formed on the lens group.   The method of manufacturing an imaging apparatus according to claim 1, wherein the index is formed on an optical axis of an effective optical surface.   The method according to claim 1, wherein the index is formed on a surface closest to the object side and a surface closest to the image side of the lens group.   An image pickup apparatus manufactured by the method for manufacturing an image pickup apparatus according to claim 1.

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