JP2008046510A - Lens unit and manufacturing method therefor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a lens unit capable of ensuring the total performance of an optical system, while increasing the productivity of a lens system that has severe tolerance sensitivity, and to provide a manufacturing method for the lens unit. <P>SOLUTION: The lens unit includes one lens holder 1110; and a plurality of lenses 120 to 140 that are held and fixed on the lens holder 110. The plurality of lenses 120 to 140 are fitted in the lens holder 110 so that the rotating angle about the respective optical axes of the lens are controlled, in order to ensure the total performance of the optical system. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a lens unit that can be applied to an imaging device in the field of image sensing with strict tolerance sensitivity, such as a digital still camera using an image sensor, a camera mounted on a mobile phone, or a camera mounted on a portable information terminal, and more particularly to a mobile phone or the like. The present invention relates to a built-in structure of an imaging optical system suitable for a digital input device (camera module) having high optical performance that can be mounted.

  In recent years, with the widespread use of mobile phones, the demand for camera modules mounted on mobile terminals has increased. And this trend is expected to become stronger.

In addition, image pickup devices have also progressed, and have become smaller and have higher pixels. For this reason, the size can be made more compact, and accordingly, the allowable manufacturing error of the lens required for maintaining the performance of the optical system is extremely small as compared with the digital still camera.
However, it is difficult to measure with the micron and sub-micron order external shape, and even if the evaluation is possible, the tolerance sensitivity becomes severe as the performance cannot be maintained by accumulating the tolerances.

Furthermore, since the number of mobile phones produced is greater than that of digital still cameras, improving yield is an important issue.
If the manufacturing method is mentioned, it is difficult to carry out stable mass production with a manufacturing method in which minute manufacturing errors are accumulated as unacceptable manufacturing errors, and the mass productivity is poor.

  In the prior art, the imaging optical system has been implemented by increasing the accuracy of each component such as a lens and a lens frame, and incorporating it so that a certain level of performance can be maintained within the stacking tolerance.

  In recent camera modules, competition for low prices is fierce, so it is necessary to keep the imaging lens low. For this purpose, resin lenses are actively used to reduce the cost by increasing the mold cavity.

  However, although the characteristics of the resin lens are different for each cavity, the lens molded in each cavity has less variation than the glass lens and stable production can be expected. Therefore, stable mass production can be expected if a lens combination that cancels the tolerance can be found.

As for an assembling method, for example, Patent Document 1 discloses a resin molded lens in which a lens trace is provided with a gate mark at the time of lens molding.
JP-A-3-33801

  However, the technique disclosed in Patent Document 1 described above does not consider canceling the tolerance of the lens in the lens frame.

  An object of the present invention is to provide a lens unit capable of ensuring the total performance of an optical system and increasing the mass productivity of a lens system with tight tolerance sensitivity, and a manufacturing method thereof.

  The lens unit according to the first aspect of the present invention has a single lens holder and a plurality of lenses held and fixed to the lens holder, and the plurality of lenses are configured to ensure the total performance of the optical system. In addition, the rotation angle about the optical axis of each lens is controlled, and the lens holder is incorporated in the lens holder.

  A lens unit manufacturing method according to a second aspect of the present invention is a lens unit manufacturing method for manufacturing a lens unit by holding and fixing a plurality of lenses to one lens holder, wherein the plurality of lenses are optical systems. In order to ensure the total performance of the lens, the rotation angle around the optical axis of each lens is controlled and incorporated in the lens holder.

  Preferably, the plurality of lenses are assembled into the lens holder in such a manner that the tilt directions of the eccentricity of each lens with respect to the optical axis are brought close to the optical axis.

  Preferably, a predetermined gate is formed on at least one of the plurality of lenses, and the plurality of lenses are incorporated in the lens holder with the gate position of the lens as a reference position in the direction of tilting eccentricity.

  Preferably, at least one of the plurality of lenses is formed with a mark for grasping a rotational position around the optical axis, and the plurality of lenses are incorporated in the lens holder as a reference position in the direction of declination of eccentricity. .

  Preferably, a mark for grasping the rotation direction of the lens centered on the optical axis is formed on the lens holder, and the plurality of lenses are incorporated into the lens holder at an appropriate angle according to the mark. Yes.

Preferably, the focal length of each lens is f _i , the focal length of the entire optical system is f, and the lens number is the first lens, the second lens, the third lens,. i-1) The following conditional expression (1) or (2) is satisfied when the angle difference formed by the projection angle of the lens and the i-th lens on the sensor surface in the direction of tilting of the optical axis is θ _i .

もしくは

Or

ただし、i≧2、0°≦θ＜360°とする。

However, i ≧ 2 and 0 ° ≦ θ <360 °.

Preferably, the lens number is the first lens, the second lens, the third lens,... The i-th lens from the dropping side to the sensor surface of the (i-1) -th lens and the i-th lens in the direction of tilting the optical axis. when the projection angle is the angle difference and theta _i forming, group transmission eccentricity sigma ₁ to the first lens, the group transmission eccentricity until the second lens sigma ₂ · · ·, the group transmission eccentricity to the i-th lens When σ _i is set and α ₁ , α ₂ , α ₃ ... α _i are the single lens decentering amounts of the first lens, the second lens, the third lens,. (3) Satisfy (4).

もしくは

Or

ただし、i≧2、0°≦θ＜360°とする。偏心量は分表示とする。

However, i ≧ 2 and 0 ° ≦ θ <360 °. Eccentricity is displayed in minutes.

Preferably, the lens holder has a lens dropping structure, and the group transmission eccentricity when the lens is incorporated in the lens holder satisfies the following conditional expression (5).
[Equation 5]
σ _i <10´00 ″ (i = 1,2,3 ...) (5)
However, the lens numbers from dropping side, a first lens, second lens, and third lens.., The group transmission eccentricity sigma ₁ to the first lens, the group transmission eccentricity sigma ₂ until the second lens, the The group transmission eccentricity σ ₃ ... Up to 3 lenses is set.

  Preferably, the plurality of lenses are incorporated at an angle at which the remaining eccentricity of the lens system is in the short side direction of the image sensor in a state where the lenses are incorporated in the lens holder.

Preferably, the focal length of the entire optical system focal length and f _i of each lens f, when the σi permeation amount of eccentricity of each lens satisfies the following conditional expression (6).

Preferably, when the lens having the shortest focal length or the transmission decentering amount of the group is σ ₁ and the lens having the second shortest focal length or the transmission decentering amount of the group is σ ₂ , the following conditional expression Satisfies (7).

  According to the present invention, it is possible to secure the total performance of the optical system and increase the mass productivity of a lens system having a tight tolerance sensitivity.

  Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings.

FIG. 1 is a simplified cross-sectional view showing the basic configuration of the imaging lens unit of the present embodiment.
FIG. 1 is a diagram illustrating a basic configuration of an imaging lens unit according to the present embodiment in a case where, for example, a three-lens configuration has an object-side dropping structure.

  As shown in FIG. 1, the imaging lens unit 100 of the present embodiment includes one lens frame (lens holder) 110, a first lens 120, a second lens 130, a third lens 140, and an image plane IP.

The lens holder 110 has a cylindrical shape, and a through hole 111 serving as a light path (optical path) is formed in the center. The holder inner wall 112 that forms the through hole 111 has first through the object side OBJS in order. A first holder part 113 for holding and fixing the lens 120, a second holder part 114 for holding and fixing the second lens 130, and a third holder part 115 for holding and fixing the third lens 140 are formed. Yes.
And the lens holder 110 is formed so that the center part of the through-hole 111 may become the optical axis AX. As will be described in detail later, the first lens 120, the second lens 130, and the third lens 140 grasp the eccentricity of each lens and hold the optical axis when holding and fixing the holder portions 113, 114, and 115. The lens is assembled into one lens holder (lens frame) 110 by controlling the rotation angle around the center.

As the image plane IP, a photosensitive surface of a solid-state imaging device such as a CCD (Charge Coupled Device) sensor or a CMOS (Complementary Metal Oxide Semiconductor) sensor is disposed.
In the present embodiment, in the drawing, the upper side is the object side (front) OBJS, and the lower side is the image side (rear).

In the present embodiment, when the first lens 120, the second lens 130, and the third lens 140 are held and fixed to the lens holder 110, the lens eccentricity generated as a manufacturing error is positively utilized, and each lens is eccentric. By grasping the above, and controlling the rotation angle around the optical axis and incorporating it into the lens holder (mirror frame) 110, the total performance of the optical system is ensured and stable mass productivity is realized.
Hereinafter, a basic example of the manufacturing method (assembly method) of the imaging lens unit 100 will be described, and then a specific example will be described.

As described above, the structure for incorporating the lens of the present embodiment into the lens holder 110 uses a lens that exceeds the allowable manufacturing error of the lens by incorporating the eccentricity generated in each of the lenses 120 to 140 in a direction that cancels out by rotation. I am doing so.
Since the decentering direction is generated to a certain extent for each lens and each cavity, a method is adopted in which a lens system that cannot be realized by the stacking tolerance can be assembled by combination with rotation.
That is, the manufacturing method of the present embodiment can use a lens that exceeds the allowable manufacturing error of the lens by incorporating the eccentricity generated in each lens in a direction that cancels out by rotation. Since the decentering direction is generated to a certain extent for each lens and each cavity, a lens system that could not be realized by the stacking tolerance can be assembled by combination with rotation.

  FIG. 2 is a diagram showing a basic configuration of transmission eccentricity.

As shown in FIG. 2, it is possible to measure the transmission eccentricity σ by entering parallel light into the lens system and imaging with an imaging device 220 such as a CCD through the objective lens 210.
Using this principle, the transmission eccentricity σ in the configuration of the present embodiment can be measured.

  FIG. 3 is a diagram illustrating a case where the transmission lens is measured by incorporating the first lens 120 into a lens holder (lens frame), for example.

As shown in FIG. 3, light from a light source (not shown) is incident as parallel light from the opening side of the through hole 111 of the lens holder 110, that is, from the object side OBJS, with the first lens 120 held by the first holder 113. The transmission eccentricity σ ₁ can be measured by imaging the light that has passed through the first lens 120 with the imaging device 220 such as a CCD through the objective lens 210.

  FIG. 4 is a diagram showing a case in which the integrated transmission eccentricity is measured by incorporating the first lens 120 and the second lens 130 into a lens holder (lens frame), for example.

As shown in FIG. 4, with the first lens 120 held by the first holder 113 and the second lens 130 held by the second holder 114, the opening side of the through hole 111 of the lens holder 110, that is, the object Light from a light source (not shown) is incident as parallel light from the side OBJS, and the light passing through the first lens 120 and further the second lens 130 is imaged by the imaging device 220 such as a CCD through the objective lens 210, thereby transmitting decentering σ. ₂ can be measured.

Hereinafter, the basic principle of this manufacturing method will be described.
In the manufacturing method of the present embodiment, the tilt directions of the decentering of the lenses with respect to the optical axis AX are combined so as to approach the optical axis AX. Hereinafter, the basic principle of this manufacturing method will be described.
In other words, the rotation direction is adjusted to cancel the eccentricity generated in each lens.
In this case, in this embodiment, the gate position is used as a mark for adjusting the rotation.

  FIG. 5 is a diagram showing a relationship between marks and angles in a resin lens gate and D-cut glass, for example.

For example, the resin lens gate position is incorporated in the lens holder (lens frame) 110 as a reference position in the direction of eccentric declination.
Alternatively, the glass lens is provided with a mark for grasping the rotational position around the optical axis, and is incorporated in the lens holder (lens frame) 110 as a reference position in the direction of tilting eccentricity.
For example, a rotation reference is provided by providing a mark such as a D-cut on a glass lens.

Alternatively, a mark for grasping the rotation direction of the lens around the optical axis AX is arranged (formed) on the lens holder (lens frame) 110, and each lens is placed in the lens holder (lens frame) 110 at an appropriate angle. Incorporate into.
For example, as shown in FIG. 6, a mark 110 a is formed so that each lens can be incorporated into a lens holder (mirror frame) 110 at an appropriate angle.

The focal length of each lens is f _i , the focal length of the entire optical system is f, and the lens number is the first lens, the second lens, the third lens,. In the present embodiment, the first lens 120, the second lens 130, and the third lens 140 are used as the first lens 120, the second lens 130, and the third lens 140 from the dropping side.
Then, three, two, or one type of mark formed on the lens or lens holder described above is applied, and the projection angle of the (i-1) th lens and the ith lens onto the sensor surface in the direction of tilting the optical axis. When the angle difference formed is θ _i , it is desirable to satisfy the following (conditional expression 1) or (conditional expression 2).

Or

  However, i ≧ 2 and 0 ° ≦ θ <360 °.

  In this case, it is desirable that the conditional expression 1 or 2 is satisfied because the angle dependency at the time of assembling a lens having higher power becomes more prominent.

Also, the lens numbers are the first lens, the second lens, the third lens,. In the present embodiment, the first lens 120, the second lens 130, and the third lens 140 are used as the first lens 120, the second lens 130, and the third lens 140 from the dropping side.
Then, three, two, or one type of mark formed on the lens or lens holder described above is applied, and the projection angle of the (i-1) th lens and the ith lens onto the sensor surface in the direction of tilting the optical axis. when the angle difference forming a theta _i, the group transmission eccentricity sigma ₁ to the first lens 120, the group transmission eccentricity to the second lens 130 sigma ₂ · · ·, the group transmission eccentricity to the i-th lens sigma _i And Further, the first lens, second lens, the single lens eccentricity of alpha ₁ of the third lens.. I-th lens, alpha _2, and alpha ₃ ... alpha _i. At this time, it is desirable to satisfy the following (conditional expression 3) and (conditional expression 4).

Or

However, i ≧ 2 and 0 ° ≦ θ <360 °. Eccentricity is displayed in minutes.

  In this case, it is desirable that the conditional expression 3 or 4 is satisfied because the angle dependency at the time of assembling a lens having a higher decentration appears more remarkably.

  Furthermore, in the present embodiment, as described above, the lens holder (lens frame) 110 has a lens dropping structure, and the group transmission eccentricity when the lens is incorporated in the lens holder (lens frame) 110 is small. It is desirable to satisfy the following (conditional expression 5).

[Equation 12]
σ _i <10´00 ″ (i = 1,2,3 ...) (5)

However, the lens numbers from dropping side, a first lens, second lens, and third lens.., The group transmission eccentricity sigma ₁ to the first lens, the group transmission eccentricity sigma ₂ until the second lens, the The group transmission eccentricity σ ₃ ... Up to 3 lenses is set.

  By adopting a configuration that satisfies Conditional Expression 5, it is possible to reduce the amount of eccentricity to within 10'00 "at each location such as the group eccentricity to the first lens 120 and the group eccentricity to the second lens 130. It is.

  FIG. 7 is a diagram illustrating the relationship of eccentricity cancellation.

For example, when the third lens 140 is strongly decentered and difficult to cancel, the second lens 130 is not adjusted in the decentration canceling direction with respect to the first lens 120, but the angle is adjusted in a direction that provides a synergistic effect of decentering. Do.
However, it should be noted that if the eccentricity of 10'00 "or more is forcibly canceled, the image performance is affected. Therefore, the operation of the eccentricity needs to be performed in an area within 10'00". In reality, eccentricity is not always suppressed in all cavities. Therefore, in order to use a lens with strong eccentricity, it is not always necessary to set the lens in the direction to cancel the eccentricity every time it is incorporated.

In addition, it is desirable that the remaining eccentricity of the lens system is incorporated at an angle that is in the short side direction of the imaging device in a state where all the lenses are incorporated in the lens holder (mirror frame) 110.
It is possible to reduce the influence of the direction blur by letting the eccentricity that cannot be canceled out with all the lenses incorporated into the short side of the sensor.

In the present embodiment, the focal length of the focal length of the entire optical system and f _i of each lens f, when the σi permeation amount of eccentricity of each lens satisfies the following conditional expression (6) Is desirable.

In the present embodiment, the lens having the shortest focal length of the imaging lens unit 100 or the transmission eccentricity of the group is σ ₁ , and the lens having the second shortest focal distance or the transmission eccentricity of the group is σ _2. It is preferable that the following conditional expression (7) is satisfied.

  Hereinafter, the manufacturing method according to the present embodiment will be described more specifically.

First, the lens rotation adjustment process will be described.
8A to 8C are diagrams for explaining the lens rotation adjustment process.

For example, assume that there are three gate-cut lenses 120a, 130a, and 140a as shown in FIG.
Next, as shown in FIG. 8B, an angle is designated with reference to the gate position of the first lens 120a.
Next, for example, as shown in FIG. 8C, the second lens 130a is fixed at the 225 ° position.
Next, as shown in FIG. 8C, the lens is incorporated in a direction in which the eccentricity is canceled.

    Hereinafter, actual data will be described as an example.

  FIG. 9 is a diagram showing the result of transmission decentration of a single lens.

First, referring to the result of the single lens transmission eccentricity, the combined eccentricity of the first lens 120 and the second lens 130 is measured as shown in FIG.
At this time, the reference is considered to be the first lens 120 where the sensitivity is severe even immediately after the stop, so the first lens 120 with the least eccentricity is the reference first.
For the second lens 130 to be combined, a lens with less eccentricity is selected.

  FIG. 10 is a diagram illustrating a result when the second lens (lens 2) is rotated with respect to the first lens (lens 1). FIG. 11 is a diagram illustrating a case where the second lens (lens 2) cannot correct the eccentricity of the first lens (lens 1).

When the second lens 130 is rotated 180 ° with respect to the first lens 120, the eccentricity is canceled.
From the above, there is a possibility of pairing with 6 in the 180 ° direction of Cav5 and 180 ° direction of Cav8.
Next, the combination that uses Cav3 for the first lens 120 is noticed.
In order to further correct the eccentricity from the state shown in FIG. 10A, a single lens having a large eccentricity is selected. Similarly, in order to further correct the decentration from the state of FIG. 10B, the second lens 130 having a large decentration is selected. In this way, the eccentricity is gradually canceled.

  However, forcible cancellation leads to an increase in the range of eccentricity, and the angular relationship between the first lens 120 and the second lens 130 that produces performance becomes severe.

FIG. 12 is a diagram showing another result when the second lens (lens 2) is rotated with respect to the first lens (lens 1).
Next, as shown in FIG. 12, the same measurement is performed with Cav2 having the same eccentricity.

According to the present embodiment, the lens eccentricity generated as a manufacturing error is positively used, and in the imaging lens unit 100 configured by a plurality of lenses, the eccentricity of each lens is grasped and the optical axis is the center. By controlling the rotation angle and incorporating it into the lens holder (mirror frame) 110, the total performance of the optical system can be secured and stable mass productivity can be realized.
For example, without making the mechanism complicated by using the gate remaining in the resin lens as a reference for positioning, the rotation angle around the optical axis of each lens is controlled in the incorporation of the imaging lens unit (optical system), By incorporating the lens holder (lens frame) 110 into the lens holder (lens frame) 110, it is possible to realize a built-in structure in the lens holder (mirror frame) that ensures the total performance of the optical system.
In the present embodiment, the lens holder 110 is not increased for rotation adjustment, and the resin lens can be rotated without using any special treatment by using the gate position.

FIG. 13 is a diagram showing the configuration and characteristic values of the optical system of a three-unit lens unit corresponding to design values.
FIG. 14 is a diagram illustrating the configuration and characteristic values of the optical system of the lens unit when the first lens is decentered.
FIG. 15 is a diagram showing the configuration and characteristic values of the optical system of the lens unit in the case where a second lens having a decentering amount that cancels out the decentering of the first lens is arranged.
The optical properties in these figures indicate the relative field height.

As can be seen from these figures, when the first lens 120 is decentered, the optical characteristics greatly deviate from the optical characteristics according to the design values. When the first lens 120 is decentered, the first lens By disposing the second lens having a decentering amount that cancels out such decentration, good optical characteristics close to the design value can be obtained.
That is, by manufacturing the imaging lens unit according to this manufacturing method, it is possible to obtain good optical characteristics without increasing the number of lens holders.

It is a simplified sectional view showing the basic composition of the imaging lens unit of this embodiment. It is a figure which shows the basic composition of transmission eccentricity. It is a figure which shows the case where a 1st lens is integrated in a lens holder (mirror frame), and a transmission eccentricity is measured. It is a figure which shows the case where it integrates in a lens holder (mirror frame) to a 2nd lens in addition to a 1st lens, and measures integral transmission eccentricity. It is a figure which shows the relationship between the mark and angle in the gate of a resin lens, and D cut glass. It is a figure which shows the example which has arrange | positioned the mark for grasping | ascertaining the rotation direction of the lens centering on the optical axis AX on a lens holder (mirror frame). It is a figure which shows the relationship of eccentric cancellation. It is a figure for demonstrating a lens rotation adjustment process. It is a figure which shows a lens single-piece | transmission decentration result. It is a figure which shows the result at the time of rotating a 2nd lens (lens 2) with respect to a 1st lens (lens 1). It is a figure which shows the case where the 2nd lens (lens 2) cannot fully correct | amend the eccentricity of a 1st lens (lens 1). It is a figure which shows the other result at the time of rotating a 2nd lens (lens 2) with respect to a 1st lens (lens 1). It is a figure which shows the structure and characteristic value of an optical system of the lens unit of 3 structure corresponding to a design value. It is a figure which shows the structure and characteristic value of the optical system of a lens unit when decentration arises in the 1st lens. It is a figure which shows the structure and characteristic value of an optical system of a lens unit at the time of arrange | positioning the 2nd lens with the amount of eccentricity which cancels so that the eccentricity of a 1st lens may be canceled.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 100 ... Imaging lens unit, 110 ... Lens holder, 120 ... 1st lens, 130 ... 2nd lens, 140 ... 3rd lens.

Claims (22)

One lens holder,
A plurality of lenses held and fixed to the lens holder,
The plurality of lenses are incorporated in the lens holder by controlling the rotation angle around the optical axis of each lens so as to ensure the total performance of the optical system. The lens unit according to claim 1, wherein the plurality of lenses are incorporated in the lens holder in such a manner that the tilt directions of the eccentricity of the lenses with respect to the optical axis are brought close to the optical axis. The at least one of the plurality of lenses is formed with a predetermined gate, and the plurality of lenses are incorporated in the lens holder with a gate position of the lens as a reference position in a declination direction of eccentricity. The lens unit described. At least one of the plurality of lenses has a mark for grasping a rotational position around the optical axis, and the plurality of lenses are incorporated in the lens holder as a reference position in a direction of tilting eccentricity. Item 3. The lens unit according to Item 1 or 2. 2. The lens holder is formed with a mark for grasping a rotation direction of the lens around an optical axis, and the plurality of lenses are incorporated into the lens holder at an appropriate angle according to the mark. Or the lens unit of 2. The focal length of each lens is f _i , the focal length of the entire optical system is f, and the lens number is the first lens, the second lens, the third lens,. The following conditional expression (1) or (2) is satisfied, where θ _i is an angle difference formed by the projection angle of the lens and the i-th lens on the sensor surface in the direction of tilting of the optical axis: The lens unit described.

Or

However, i ≧ 2 and 0 ° ≦ θ <360 °. The lens number is the first lens, the second lens, the third lens ... i-th lens from the drop-in side, and the projection angle of the (i-1) -th lens and i-th lens onto the sensor surface in the direction of tilting the optical axis is when the angular difference formed between theta _i, a first group transmitting eccentricity sigma ₁ to the lens, the group transmission eccentricity until the second lens sigma ₂ · · ·, the group transmission eccentricity sigma _i to the i-th lens, Furthermore, when the lens single lens decentering amounts of the first lens, the second lens, the third lens,..., The i-th lens are α ₁ , α ₂ , α _3, α _i , the following conditional expression (3) ( The lens unit according to claim 1, wherein 4) is satisfied.

Or

However, i ≧ 2 and 0 ° ≦ θ <360 °. Eccentricity is displayed in minutes. The lens according to any one of claims 1 to 7, wherein the lens holder has a lens drop structure, and a group transmission decentering amount in a state where the lens is incorporated in the lens holder satisfies the following conditional expression (5). unit.
[Equation 5]
σ _i <10´00 ″ (i = 1,2,3 ...) (5)
However, the lens numbers from dropping side, a first lens, second lens, and third lens.., The group transmission eccentricity sigma ₁ to the first lens, the group transmission eccentricity sigma ₂ until the second lens, the The group transmission eccentricity σ ₃ ... Up to 3 lenses is set. 9. The lens unit according to claim 1, wherein the plurality of lenses are incorporated at an angle at which a remaining eccentricity of the lens system is in a short side direction of the imaging element in a state where the lens is incorporated in the lens holder. . The focal length of the focal length of the entire optical system and f _i of each lens f, when the σi permeation amount of eccentricity of the lens, in any one of claims 1 to 9 satisfies the following conditional expression (6) The lens unit described.

When the shortest focal length lens or group transmission decentering amount is σ ₁ and the second shortest focal length lens or group transmission decentering amount is σ ₂ , the following conditional expression (7) The lens unit according to any one of claims 1 to 9.

A lens unit manufacturing method for manufacturing a lens unit by holding and fixing a plurality of lenses to one lens holder,
A method of manufacturing a lens unit, wherein the plurality of lenses are incorporated into the lens holder by controlling a rotation angle about the optical axis of each lens so as to ensure the total performance of the optical system. The method of manufacturing a lens unit according to claim 12, wherein the plurality of lenses are assembled into the lens holder in such a manner that the tilt directions of the eccentricity of the lenses with respect to the optical axis are brought close to the optical axis. Forming a predetermined gate on at least one of the plurality of lenses;
The method of manufacturing a lens unit according to claim 12 or 13, wherein the plurality of lenses are incorporated into the lens holder with the gate position of the lens as a reference position in the direction of tilting eccentricity. Forming a mark on at least one of the plurality of lenses for grasping a rotational position around the optical axis;
The method of manufacturing a lens unit according to claim 12 or 13, wherein the plurality of lenses are incorporated in the lens holder as a reference position in a declination direction. Forming a mark on the lens holder for grasping the rotation direction of the lens around the optical axis;
The method of manufacturing a lens unit according to claim 12 or 13, wherein the plurality of lenses are incorporated into the lens holder at an appropriate angle according to the mark. The focal length of each lens is f _i , the focal length of the entire optical system is f, and the lens number is the first lens, the second lens, the third lens,. The following conditional expression (1) or (2) is satisfied, where θ _i is an angle difference formed by the projection angle of the lens and the i-th lens on the sensor surface in the direction of tilting of the optical axis: The manufacturing method of the lens unit of description.

Or

However, i ≧ 2 and 0 ° ≦ θ <360 °. The lens number is the first lens, the second lens, the third lens ... i-th lens from the drop-in side, and the projection angle of the (i-1) -th lens and i-th lens onto the sensor surface in the direction of tilting the optical axis is when the angular difference formed between theta _i, a first group transmitting eccentricity sigma ₁ to the lens, the group transmission eccentricity until the second lens sigma ₂ · · ·, the group transmission eccentricity sigma _i to the i-th lens, Furthermore, when the lens single lens decentering amounts of the first lens, the second lens, the third lens,..., The i-th lens are α ₁ , α ₂ , α _3, α _i , the following conditional expression (3) ( The method for manufacturing a lens unit according to any one of claims 12 to 16, wherein 4) is satisfied.

Or

However, i ≧ 2 and 0 ° ≦ θ <360 °. Eccentricity is displayed in minutes. The lens according to any one of claims 12 to 18, wherein the lens holder has a lens drop structure, and a group transmission decentering amount in a state in which the lens is incorporated in the lens holder satisfies the following conditional expression (5). Unit manufacturing method.
[Equation 12]
σ _i <10´00 ″ (i = 1,2,3 ...) (5)
However, the lens numbers from dropped side, a first lens, second lens, and third lens.., The group transmission eccentricity sigma ₁ to the first lens, the group transmission eccentricity sigma ₂ until the second lens, the The group transmission eccentricity σ ₃ ... Up to 3 lenses is set. The method of manufacturing a lens unit according to any one of claims 12 to 19, wherein the plurality of lenses are incorporated at an angle at which a remaining eccentricity of the lens system is in the short side direction of the imaging device in a state where the lenses are incorporated in the lens holder. . The focal length of the focal length and f _i the entire optical system of each lens f, and transmission eccentricity of each lens when the .sigma.i, in any one of claims 12 to 20 which satisfies the following conditional expression (6) The manufacturing method of the lens unit of description.

When the shortest focal length lens or group transmission decentering amount is σ ₁ and the second shortest focal length lens or group transmission decentering amount is σ ₂ , the following conditional expression (7) The method for manufacturing a lens unit according to any one of claims 12 to 20.

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