JP2008228246A - Lens unit, lens module and camera module - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a lens module which suppresses a resolution defect while attaining improvement in manufacture workability. <P>SOLUTION: A lens unit 2 includes: lenses 4, 6; a barrel 2a which houses the lenses 4, 6 therein; a lens presser 7 which holds the lenses 4, 6 at a predetermined position in the barrel 2a in contact with the inner side surface of the barrel 2a and has a notched portion apart from the inner side surface of the barrel 2a; and an adhesive 8 which is disposed in a gap formed between the inner side surface of the barrel 2a and the notched portion of the lens presser 7 and adheres the barrel 2a and the lens presser 7. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a lens unit, a lens module, and a camera module mounted on, for example, a mobile phone.

For example, in a lens module of a small camera module used for a mobile phone or a surveillance camera, the lens is housed in a barrel and fixed with an adhesive for positioning.
As for image sensor modules that are used in cellular phones, etc., for example, the lens is pressed against the step by the elastic force based on the elastic deformation of the lens holder attached to the housing, and the lens height is accurately set. There is a technique for obtaining a clear image by defining (see, for example, Patent Document 1).

JP 2004-40287 A

In recent years, with the aim of further reducing the size of camera modules used in imaging devices such as mobile phones and improving production efficiency, after mounting a camera module with an image sensor on a lens module on a circuit board with electronic components The manufacture of solder welding in a reflow furnace has come to be performed. In this manufacturing method, all the components need to have heat resistance at the reflow temperature.
As an adhesive that can withstand this reflow temperature, for example, an epoxy-based thermosetting adhesive can be mentioned, but the thermosetting adhesive shrinks when cured compared to a conventional silicon-based adhesive that does not have heat resistance. It has the characteristic that the rate is large.
For this reason, in a lens module that employs this adhesive, stores the lens in the barrel, holds it with a lens holder, and adheres and fixes the lens holder from the back, the lens position shifts due to shrinkage during curing. As a result, there was a risk of optical axis misalignment and poor resolution.

  The present invention has been made to solve such a technical problem, and an object of the present invention is to provide a lens module or the like that suppresses poor resolution while improving the assembly workability. .

  In order to solve the above-described problems, a lens unit according to the present invention includes a lens, a barrel that houses the lens, and an inner surface of the barrel to hold the lens in a predetermined position in the barrel. A lens holding member having a separating portion that is spaced apart from the side surface; and an adhesive that is disposed in a gap formed between the inner side surface of the barrel and the separating portion of the lens pressing member and that bonds the barrel and the lens pressing member. And

In the above lens unit, the lens has a substantially disc shape, the barrel has a cylindrical shape, and the lens retainer has a substantially annular shape having a notch part of the outer peripheral surface, and is bonded. The agent is characterized in that it is disposed in a gap formed between the inner surface of the barrel and the notch portion of the lens presser.
In the lens unit, the lens holder is characterized in that the notch portions are evenly arranged with the central axis of the lens holder as the center symmetry.

  In order to solve the above problem, the lens unit includes a lens unit and a pedestal mount to which the lens unit is attached. The lens unit includes a substantially disk-shaped lens, a barrel having a cylindrical shape for housing the lens, and a substantially annular ring. It has a shape and includes a lens holder that holds the lens at a predetermined position in the barrel, and fixing means that fixes the inner surface of the barrel and the lens holder in a state of being pulled in the radial direction of the lens.

In the lens module, the fixing means includes a notch provided in a part of the outer peripheral surface of the lens holder, and a thermosetting adhesive disposed in a gap formed between the notch and the barrel. It is characterized by including.
In the lens module described above, the lens has a cutout portion in which a part of the outer peripheral surface is cut out, and the lens presser has a cutout portion of the lens presser as viewed from the optical axis direction of the lens. It is attached so that it may be arrange | positioned in a different position.

  In order to solve the above problems, the lens unit includes a lens unit, an image sensor that converts light imaged by the lens unit into an electrical signal, and a pedestal mount that houses the image sensor and to which the lens unit is attached. The lens has a substantially disc-shaped lens, a barrel having a cylindrical shape for housing the lens, a substantially annular shape, and has a cutout portion in which a part of the outer peripheral surface of the annular shape is cut out. Is placed in the gap between the lens holder that holds the lens in place in the barrel and the inner surface of the barrel and the notch of the lens holder, and the barrel and the lens holder are pulled in the radial direction of the lens. It is characterized by including an adhesive which adheres with.

  According to the present invention, the adhesive enters the gap formed between the inner surface of the barrel and the separation portion of the lens holder, and bonds the barrel and the lens holder. Therefore, even if the adhesive shrinks during curing, the lens does not shift in the optical axis direction. Thereby, the optical axis shift of a lens and the resolution defect of a camera module can be suppressed.

The best mode (embodiment) for carrying out the present invention will be described below in detail with reference to the accompanying drawings.
FIG. 1 is an external perspective view showing a lens module 1 according to this embodiment, and FIG. 2 is an exploded perspective view of the lens module 1 according to this embodiment.
As shown in FIGS. 1 and 2, the lens module 1 holds two lenses 4 and 6, and includes a lens unit 2 that focuses incident light on a sensor 16 (see FIG. 7), and a lens unit 2. And a pedestal 3 as an example of a pedestal mount to be held.

The lens unit 2 includes a barrel (holder) 2a constituting the lens unit 2 main body, and two lenses 4 and 6 held by the barrel 2a. In the present embodiment, an intermediate ring 5 is disposed between the two lenses 4 and 6. The lens 6 is pressed by a lens presser 7.
The lenses 4 and 6 are optical elements that allow external light to pass through and form an image on the light receiving region (imaging area) of the sensor 16 (see FIG. 7). That is, the lenses 4 and 6 form a predetermined optical system so that external light enters from the opening 2 b and forms an image on the light receiving region of the sensor 16. In the present embodiment, the lens unit 2 is composed of two lenses 4 and 6, but the number of lenses may be one or three. The predetermined optical system includes a single lens or a plurality of lens groups.

The lens unit 2 is screwed into the cylindrical portion 3a of the pedestal 3, and image adjustment is performed by a screw action. After the image formation adjustment, the lens unit 2 is fixed to the pedestal 3 with an adhesive (not shown). Thereby, the focusing of the lens module 1 is realized.
The barrel 2a and the pedestal 3 have a light shielding property such as a black liquid polymer (LCP), a polyphthalamide resin, a PEEK (polyether ether ketone) resin, and have a heat resistance that can withstand a reflow temperature. Consists of. Here, the heat resistant temperature is desirably 200 ° C. or higher, and more desirably 260 to 300 ° C.
In the barrel 2a, an opening 2b is formed on the end face side of the barrel 2a into which external light is incident.

The lenses 4 and 6 are made of, for example, a synthetic resin such as a transparent silicone resin or a resin having heat resistance such as glass. Since the entire lens module 1 is put into a reflow furnace, the heat-resistant temperature of the lenses 4 and 6 is desirably 200 ° C. or higher, more preferably 260 to 300 ° C., which is the same as that of the barrel 2a and the pedestal 3.
The intermediate ring 5 is made of, for example, a synthetic resin film such as stretched polyester (PET) kneaded with carbon black. The intermediate ring 5 has a diaphragm function for limiting the amount of light passing therethrough.

FIG. 3 is a perspective view of the lens 6 according to the present embodiment.
When the lens 6 is manufactured by injection molding of synthetic resin, a cut mark (burr) is generated in the gate portion 6a of the lens 6 when the gate is cut. When the lens 6 is stored in the barrel 2a, the gate 6a on the outer periphery of the lens 6 has a D-cut surface (in order to prevent the burr from coming into contact with the inner surface of the barrel 2a and deteriorating the assembling workability of the lens module 1. Flat surface) 6b is formed. The lens 4 also has a D-cut surface at the gate portion as in the lens 6 (see FIG. 2).

The pedestal 3 is configured integrally with a cylindrical portion 3a to which the lens unit 2 is attached and a rectangular portion 3b that accommodates and holds the filter 15, the sensor 16, and the glass cover 17 (see FIG. 7 for all). Moreover, the base 3 is comprised so that the internal space of the cylindrical part 3a and the internal space of the rectangular part 3b may continue (refer FIG. 4). The pedestal 3 has a flange portion 3d (see FIG. 4) formed so as to extend from the inner surface and narrow the internal space.
A female screw 3 c is formed on the inner peripheral surface of the cylindrical portion 3 a of the pedestal 3, and a male screw 2 c corresponding to the female screw 3 c is formed on the outer peripheral surface of the lens unit 2. As will be described later, the lens unit 2 is attached to the cylindrical portion 3a of the pedestal 3 by screwing.

FIG. 4 is a longitudinal sectional view of the lens module 1 according to the present embodiment.
As shown in FIG. 4, the lens unit 2 includes a barrel 2a constituting the lens unit 2 body, and two lenses 4 and 6 held by the barrel 2a. An intermediate ring 5 is provided between the two lenses 4 and 6. The lens 6 is pressed by a lens presser 7.
The lens holder 7 is composed of a mixture of polycarbonate resin, glass fiber, and black pigment such as carbon black. The lens retainer 7 is in contact with the inner surface of the barrel 2a and holds the lens 6 at a predetermined position in the barrel 2a. Further, the lens presser 7 is provided with a separation portion that is separated from the inner surface of the barrel 2a, and flat surfaces 7a and 7b as an example of notches (see FIG. 5).

FIG. 5 is a perspective view of the lens retainer 7 according to the present embodiment.
As shown in FIG. 5, two flat surfaces 7 a and 7 b as examples of notches are formed symmetrically on the outer peripheral surface of the lens holder 7. Note that the number of flat surfaces is not limited to two, and a plurality of, for example, 2 to 4, flat surfaces are preferably formed on the outer peripheral surface. As will be described later, since the D-cut surface 6b of the lens 6 and the two flat surfaces 7a and 7b of the lens presser 7 are arranged so as not to overlap, the number of flat surfaces 7a and 7b formed on the lens presser 7 is as follows. Naturally limited.
Note that the separation portion or the notch portion formed in the lens holder 7 does not need to be flat as shown as flat surfaces 7a and 7b in FIG. For example, a gate mark as indicated by the gate portion 6a in FIG. 3 may remain. A curved surface may be used as long as it forms a gap with the inner surface of the barrel 2a. For example, the convex surface which has a larger curvature radius than the curvature radius of the inner surface of the barrel 2a may be sufficient, and a concave surface may be sufficient.

Returning to FIG. 4, the adhesive 8 is disposed in a gap formed by the flat surfaces 7a and 7b of the lens retainer 7 and the inner surface of the barrel 2a to fix the lens retainer 7 and the barrel 2a. The adhesive 8 functions as an example of a fixing unit together with the flat surfaces 7 a and 7 b of the lens presser 7.
As the adhesive 8, a thermosetting or UV curable adhesive, for example, an epoxy heat-resistant adhesive is preferably used. A heat-resistant adhesive that does not impair the bonding performance when the lens module 1 is attached to a circuit board, placed in a reflow oven, and exposed to high temperatures is preferred. Here, the heat resistant temperature of the adhesive 8 is desirably 200 ° C. or higher, and more desirably 260 to 300 ° C.
Further, the adhesive 8 is desired to have a small shrinkage rate under high temperature, and for example, an adhesive with filler is preferably employed. For example, glass fiber is used as the filler. Specifically, the one-component thermosetting epoxy resin 2252 (filler) made by Three Bond Co., which has a cure shrinkage of 2.12%, and the one-component, made by Gurelab, which has a shrinkage rate of 3.1% when cured. Thermosetting epoxy resin GL-2001 (with filler) is used.

Here, an example of a problem when the lens is fixed using the lens press will be described with reference to FIGS.
FIG. 8 is a longitudinal cross-sectional view of the lens module 11 of this problem example, and FIG. 9 is a diagram for explaining a contracted state when the adhesive 8 is cured in the lens module 11 shown in FIG. FIG. 9A shows a state when the lens holder 12 and the barrel 2a are bonded using the adhesive 8 in the manufacturing process of the lens module 11, and FIG. 9B shows the state after the adhesive 8 is cured. Shows the state.
8 and 9, the same components as those in FIG. 4 are denoted by the same reference numerals, and the following description is omitted.

In FIG. 8, the lens 6 is pressed by the lens presser 12 in order to prevent the lens 6 from falling out of the barrel 2 a. The lens presser 12 is bonded to the barrel 2a with an adhesive 8 from the side opposite to the lens 6 (the lower side in the figure).
As can be seen from FIG. 9, when the inner surface of the barrel 2 a and the lens presser 12 are bonded with the adhesive 8, the lens presser 12 is pulled in the optical axis direction of the lens 6 due to shrinkage when the adhesive 8 is cured. A gap (backlash) is generated between the lens 6 and the lens holder 12 (see FIG. 9B). Since this backlash occurs in the same direction as the optical axis of the lens 6, there is a risk that the lens 6 will be displaced, resulting in an optical axis shift or poor resolution.

On the other hand, the state at the time of adhesion | attachment of the lens unit 2 concerning this Embodiment is demonstrated.
FIG. 6 is an enlarged longitudinal sectional view of the vicinity of the lens holder 7 of the lens unit 2 according to the present embodiment.
As shown in FIG. 6A, an adhesive 8 enters a gap formed by the flat surface 7a of the lens retainer 7 and the inner surface of the lens unit 2 to bond them together. Since the adhesive 8 contracts in the radial direction of the lenses 4 and 6 at the time of contraction, the lenses 4 and 6 do not move in the optical axis direction even if the lens retainer 7 moves due to the contraction of the adhesive 8. Therefore, there is no backlash in the lenses 4 and 6, and no optical axis shift or resolution failure due to the optical axis shift occurs.
FIG. 6B shows another embodiment of the present invention. The lens retainer 9 has a step formed on a cut surface 9a as an example of a notch, and widens the contact area with the adhesive 8. As a result, the lens retainer 9 is more firmly bonded to the lens unit 2.

A method for assembling (manufacturing) the lens module 1 described above will be described.
FIG. 7 is an exploded perspective view of the camera module 20 according to the present embodiment.
The lens 4 is press-fitted into the barrel 2a, and then the intermediate ring 5 is accommodated. Then, the lens 6 is press-fitted so that the intermediate ring 5 is sandwiched between the lens 4 and the lens holder 7.
At this time, the D-cut surface 6 b formed on the outer periphery of the lens 6 and the two flat surfaces 7 a and 7 b formed on the outer peripheral surface of the lens holder 7 do not overlap each other when viewed from the optical axis direction of the lenses 4 and 6. It arrange | positions in the position of a right angle and is integrated in the barrel 2a (refer FIG. 2). Thereafter, the adhesive 8 is put into the gap formed by the two flat surfaces 7a, 7b of the lens retainer 7 and the inner surface of the barrel 2a, and the lenses 4, 6 are positioned.
Here, the D-cut surface 6b of the lens 6 and the flat surfaces 7a and 7b of the lens retainer 7 do not necessarily have to be arranged at a right angle. It is sufficient that the adhesive 8 has a positional relationship such that the adhesive 8 does not enter the gap between the D-cut surface 6b of the lens 6 and the barrel 2a through the gap between the flat surfaces 7a and 7b of the lens holder 7. For this purpose, any positional relationship that does not overlap when viewed from the optical axis direction of the lenses 4 and 6 may be used.

Return to description of assembly method. The lens unit 2 is screwed and attached to the cylindrical portion 3a of the pedestal 3, and the lens module 1 is assembled.
Finally, the sensor 16 and the filter 15 attached to the glass cover 17 are attached to the lens module 1, and the camera module 20 is completed.

Thus, according to the lens module 1 according to the present embodiment, the adhesive 8 that can withstand the reflow temperature contracts in the radial direction of the lens 6. Therefore, it is possible to avoid the optical axis misalignment and poor resolution due to the shrinkage of the adhesive 8.
The lens retainer 7 is formed with flat surfaces 7 a and 7 b that are evenly formed on the outer peripheral surface with the central axis of the lens retainer 7 as the center symmetry. Therefore, the influence of the deformation of the lens presser 7 due to the shrinkage of the adhesive 8 can be suppressed.
In the above embodiment, the substantially disk-shaped lenses 4 and 6 and the substantially annular lens retainer 7 are described as examples in FIG. 2, but the present invention is not limited to this. In a configuration in which the lens is held at a predetermined position in the barrel by adhering the lens press to the barrel, the lens press is formed between the barrel and the lens press so that the shrinkage when curing the adhesive is in the radial direction of the lens. It is sufficient if an adhesive is placed in the gap. The shape of the lens may be a square, for example.

Since the adhesive 8 that can withstand the reflow temperature can be employed, the camera module 20 on which the lens module 1 is mounted can be placed in a reflow furnace. As a result, the work of mounting the lens module 1 alone on the circuit board separately from the other electronic components and the work of joining the lens module 1 alone to the circuit board can be omitted, and workability can be improved.
Further, the mounter can mount the camera module 20 on the circuit board. Therefore, the mounting workability can be improved.

  The mounting area can be reduced by automatic mounting by the mounter. Therefore, the camera module 20 can be downsized. Compared to the conventional product in which the FPC board on which the camera module is mounted is connected to the connector after mounting the electronic component on the circuit board, the mounting area ratio of the component can be reduced to about 50% of the conventional product.

It is an external appearance perspective view of the lens module concerning this Embodiment. It is a disassembled perspective view of the lens module shown in FIG. FIG. 3 is a perspective view of the lens shown in FIG. 2. It is a longitudinal cross-sectional view of the lens module shown in FIG. FIG. 3 is a perspective view of a lens presser shown in FIG. 2. It is the longitudinal cross-sectional view which expanded the lens holding | suppressing vicinity of the lens unit shown in FIG. It is a disassembled perspective view of the camera module concerning this Embodiment. It is a longitudinal cross-sectional view of the lens module of the example which becomes a problem. It is a figure explaining the state of contraction when an adhesive agent hardens | cures in the lens module shown in FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1,11 ... Lens module, 2 ... Lens unit, 2a ... Barrel, 3 ... Pedestal (pedestal mount), 4, 6 ... Lens, 6b ... D cut surface (flat surface), 7, 12 ... Lens press, 7a, 7b ... Flat surface (separation part, notch part, fixing means), 8 ... Adhesive (fixing means), 20 ... Camera module

Claims (7)

A lens,
A barrel for housing the lens;
A lens retainer that contacts the inner surface of the barrel and holds the lens in a predetermined position in the barrel, and has a separating portion that is separated from the inner surface of the barrel;
A lens unit comprising: an adhesive that is disposed in a gap formed between the inner side surface of the barrel and the separation portion of the lens pressing member and bonds the barrel and the lens pressing member. The lens has a substantially disc shape,
The barrel has a cylindrical shape,
The lens retainer has a substantially annular shape having a notch part of the outer peripheral surface.
The lens unit according to claim 1, wherein the adhesive is disposed in the gap formed between the inner side surface of the barrel and the notch portion of the lens presser.   3. The lens unit according to claim 2, wherein the notch portion is equally arranged with the center axis of the lens retainer as a center symmetry. A lens unit;
A pedestal mount to which the lens unit is attached,
The lens unit is
A substantially disk-shaped lens;
A barrel having a cylindrical shape for housing the lens;
A lens retainer that is generally annular and that holds the lens in place within the barrel;
A lens module comprising: fixing means for fixing an inner surface of the barrel and the lens pressing member in a state of being pulled in a radial direction of the lens.   The fixing means includes a notch provided in a part of the outer peripheral surface of the lens retainer, and a thermosetting adhesive disposed in a gap formed between the notch and the barrel. The lens module according to claim 4. The lens has a notch part of the outer peripheral surface,
The lens retainer is attached so that the cutout portion of the lens retainer is disposed at a position different from the notch portion of the lens when viewed from the optical axis direction of the lens. Item 6. The lens module according to Item 5. A lens unit;
An image sensor that converts light imaged by the lens unit into an electrical signal;
A pedestal mount that houses the imaging device and to which the lens unit is attached;
The lens unit is
A substantially disk-shaped lens;
A barrel having a cylindrical shape for housing the lens;
A lens retainer that has a substantially annular shape, has a notch formed by cutting out a part of the outer peripheral surface of the ring, and holds the lens in a predetermined position in the barrel;
An adhesive that is disposed in a gap formed between the inner surface of the barrel and the notch portion of the lens presser and bonds the barrel and the lens presser in a state of being pulled in the radial direction of the lens. A camera module comprising:

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