# Patent

## Title
Flexible printed board mounting structure and optical pick up having the same

## Abstract

A flexible printed board mounting structure includes a main body that has an attachment portion on its rear side surface, and a flexible printed board that is attached to the rear side surface and the attachment portion of the main body. The surface of the attachment portion is substantially perpendicular to the rear side surface. The flexible printed board includes a first area that is at least partially attached to the rear side surface of the main body, an attachment area to which a light-receiving IC is attached, the attachment area being attached to the attachment portion of the main body, and a connecting portion that is unitarily formed with the first area and the attachment area and connects the first area and the attachment area in a deflective manner. The position of the light-receiving IC can be easily adjusted relative to the attachment portion of the main body.

## Background
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a structure for mounting a flexible printed board and an optical pick up having the flexible printed board mounting structure. More specifically, the present invention relates to a structure in which a light-receiving IC is mounted on a flexible printed board is installed on the main body of an optical pickup.
2. Background Information
Driving devices for optical disks generally include an optical pick up. Such optical pick up generally includes a bi-axial actuator and a slide base that houses the bi-axial actuator. The slide base has an objective lens through which light from a light source such as a semiconductor laser is collected on the optical disk. Photodiode is an example of the known light source. The bi-axial actuator shifts the objective lens in two directions (focus direction and tracking direction) to focus the light on the surface of the optical disk.
An example of the flexible printed board in accordance with the conventional art is shown in FIGS. 7 and 8. The flexible printed board 160 of this conventional art is to be attached to a sliding base 122, which has a mounting hole 140 for mounting a photodiode PD on the side surface 131. The mounting hole 140 has a vertically symmetrical shape relative to a horizontal line. A positioning hole 142 is formed on the sliding base 122 so as to be connected with the mounting hole 140. This positioning hole 142 is adapted to fit over the lens 144 of the photodiode PD. The lens 144 has a substantially hemispherical shape. Two grooves 146, 146 are formed in the mounting hole 140, on which an adhesive B is to be applied. An adhesive surface 162 of the flexible printed board 160 is attached to the peripheral surface 150 around the mounting hole 140 and to the bottom surface 132 of the sliding base 122. An example of such structure is disclosed in, for example, Japanese Patent Application Publication No. 7-263836.
In this structure, as shown in FIGS. 7-8, the photodiode PD is positioned at the attachment place (the mounting hole 140 and the positioning hole 142) by bending the flexible printed board 160 at a border 163 by about 180 degrees. Here, the distance LC between the border 163 and the upper edge of the photodiode PD is substantially the same as the distance LE between the upper edge of the side surface of the sliding base 122 and the upper edge of the mounting hole 140. In other words, the photodiode PD of the flexible printed board 160 is disposed in the attachment place by tightly attaching the bent portion of the flexible printed board 160 to the side surface of the sliding base 122. (ADDED btw 0002-0003)
Such structure, however, requires high precision in manufacturing and positioning of the components. Accordingly, it has been a problem that the mounting position of the lens 144 of the photodiode PD tends to be misaligned.
In view of the above, it will be apparent to those skilled in the art from this disclosure that there exists a need for improved flexible printing board mounting structure and optical pick up that overcome the problems of the conventional art. This invention addresses this need in the art as well as other needs, which will become apparent to those skilled in the art from this disclosure.
SUMMARY OF THE INVENTION
It is an object of the present invention to provide a flexible printed board mounting structure and an optical pick up in which the position of the flexible printed board can be easily adjusted relative to the attachment portion of the main body.
A flexible printed board mounting structure in accordance with the first aspect of the present invention includes a main body and a flexible printed board attached to at least the rear side surface and the attachment portion of the main body. The main body has a front side surface, a rear side surface, and an attachment portion that is on the rear side surface. A surface of the attachment portion is substantially perpendicular to the rear side surface. The flexible printed board includes a first area that is at least partially attached to the rear side surface of the main body, an attachment area to which a light-receiving IC is attached, the attachment area being attached to the attachment portion of the main body, and a connecting portion that is unitarily formed with the first area and the attachment area and connects the first area and the attachment area in a deflective manner.
With this structure, since the connecting portion loosely connects the first area and the attachment area in a deflective manner, it is possible to make adjustments in the position of the attachment area relative to the attachment portion of the main body.
The flexible printed board mounting structure in accordance with the second aspect of the present invention is the flexible printed board mounting structure in accordance with the first aspect of the present invention, in which the flexible printed board further includes a second area that is folded to face the first area, and an interlocking portion formed unitarily with the second area. The first area has an interlocking hole formed thereon. The interlocking portion interlocks with the interlocking hole.
With this structure, due to the interlocking portion that interlocks with the interlocking hole, the first and second areas are folded with a clearance therebetween. Accordingly, the position of the attachment area of the flexible printed board relative to the attachment portion of the main body can be adjusted even more easily.
The flexible printed board mounting structure in accordance with the third aspect of the present invention is the flexible printed board mounting structure in accordance with the first aspect of the present invention, in which the interlocking portion is substantially arrow-shaped.
Since the interlocking portion is arrow-shaped, the interlocking portion can be easily inserted into and remain interlocked with the interlocking hole.
The flexible printed board mounting structure in accordance with the fourth aspect of the present invention is the flexible printed board mounting structure in accordance with the second aspect of the present invention, in which the interlocking hole is an elongated hole that extends in a first direction, and the interlocking portion has a portion that extends in a second direction, the second direction intersecting with the first direction.
With the above structure, interlocking portion can be easily inserted into the interlocking hole by twisting the interlocking portion. The interlocking portion can then remain interlocked with the interlocking hole stably.
The flexible printed board mounting structure in accordance with the fifth aspect of the present invention is the flexible printed board mounting structure in accordance with the fourth aspect of the present invention, in which the interlocking portion is substantially cross-shaped.
The flexible printed board mounting structure in accordance with the sixth aspect of the present invention is the flexible printed board mounting structure in accordance with the second aspect of the present invention, in which the interlocking hole is a L-shaped slot that opens to an edge of the first area.
With the structure, the interlocking portion is easily inserted into an interlocking hole which is a substantially L-shaped slot from the opening of the slot, and the interlocking portion can remain interlocked with the bent portion of the interlocking hole.
The flexible printed board mounting structure in accordance with the seventh aspect of the present invention is the flexible printed board mounting structure in accordance with the sixth aspect of the present invention, in which the interlocking portion is substantially T-shaped.
The flexible printed board mounting structure in accordance with the eighth aspect of the present invention is the flexible printed board mounting structure in accordance with the first aspect of the present invention, in which the connecting portion connects the first area with an end of the attachment area that is farther from the rear side surface of the main body.
The flexible printed board mounting structure in accordance with the ninth aspect of the present invention is the flexible printed board mounting structure in accordance with the second aspect of the present invention, in which the first area is attached to the rear side surface of the main body via a first side of the second area, and the light-receiving IC is attached to the first side of the attachment area.
An optical pick up in accordance with the tenth aspect of the present invention includes an objective lens; a main body; and a flexible printed board. The main body has a front side surface on which the objective lens is provided, a rear side surface, and an attachment portion that is on the rear side surface. A surface of the attachment portion is substantially perpendicular to the front and rear side surfaces. The flexible printed board is attached to at least the rear side surface and the attachment portion of the main body. The flexible printed board has a first area, a second area that is folded to face the first area, an attachment area to which the first side of which a light-receiving IC is attached, a connecting portion, and an interlocking portion formed unitarily with the second area. The first area has an interlocking hole formed thereon. The first area is at least partially attached to the rear side surface of the main body via a first side of the second area. The attachment area is attached to the attachment portion of the main body. The connecting portion is unitarily formed with the first area and the attachment area and connects in a deflective manner the first area and an end of the attachment area that is farther from the rear side surface of the main body. The interlocking portion interlocks with the interlocking hole.
The optical pick up in accordance with the eleventh aspect of the present invention is the optical pick up in accordance with the tenth aspect of the present invention, in which the interlocking portion is substantially arrow-shaped.
The optical pick up in accordance with the twelfth aspect of the present invention is the optical pick up in accordance with the tenth aspect of the present invention, in which the interlocking hole is an elongated hole that extends in a first direction, and the interlocking portion has a portion that extends in a second direction, the second direction intersecting with the first direction.
The optical pick up in accordance with the thirteenth aspect of the present invention is the optical pick up in accordance with the twelfth aspect of the present invention, in which the interlocking portion is substantially cross-shaped.
The optical pick up in accordance with the fourteenth aspect of the present invention is the optical pick up in accordance with the twelfth aspect of the present invention, in which the interlocking hole is a L-shaped slot that opens to an edge of the first area.
The optical pick up in accordance with the fifteenth aspect of the present invention is the optical pick up in accordance with the twelfth aspect of the present invention, in which the interlocking portion is substantially T-shaped.
These and other objects, features, aspects and advantages of the present invention will become apparent to those skilled in the art from the following detailed description, which, taken in conjunction with the annexed drawings, discloses a preferred embodiment of the present invention.



BRIEF DESCRIPTION OF THE DRAWINGS
Referring now to the attached drawings which form a part of this original disclosure:
FIG. 1 is a perspective view of an optical pickup having a structure for mounting a flexible printed board of the first embodiment as seen from the back;
FIG. 2 is a perspective view of the optical pickup in FIG. 1 as seen from the front;
FIG. 3 is a projection of the flexible printed board in the structure for mounting a flexible printed board in the first embodiment;
FIG. 4 shows a state in which the first area and second area of the flexible printed board shown in FIG. 3 are folded by about 180 degrees, and an interlocking portion is inserted and interlocked in an interlocking hole, wherein (a) is a schematic front view of a state in which the first area and second area are overlapping, and (b) is a schematic front view of a state in which the second area is slightly raised up from the state in (a);
FIG. 5 is a projection of the flexible printed board in the structure for mounting a flexible printed board of the second embodiment;
FIG. 6 is a projection of the flexible printed board in the structure for mounting a flexible printed board of the third embodiment;
FIG. 7 is a perspective view showing a sliding base of an optical pickup, a flexible printed board, and a photodiode in a conventional printed board; and
FIG. 8 is a cross-sectional view showing the sliding base, the flexible printed board, and the photodiode in the same printed board in an integrally mounted state.



DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
Selected embodiments of the present invention will now be explained with reference to the drawings. It will be apparent to those skilled in the art from this disclosure that the following descriptions of the embodiments of the present invention are provided for illustration only and not for the purpose of limiting the invention as defined by the appended claims and their equivalents.
The embodiments of the structure for mounting a flexible printed board relating to the present invention will now be described with reference to the diagrams.
FIG. 1 is a perspective view of an optical pickup 1 having a flexible printed board mounting structure in accordance with the first embodiment, as seen from the reverse side. FIG. 2 is a perspective view of the optical pickup shown in FIG. 1 as seen from the front side. FIG. 3 is a projection of the flexible printed board used in the flexible printed board mounting structure in accordance with the first embodiment. FIG. 4 shows the state of the flexible printed board as attached to the main body, with the first area and second area of the flexible printed board shown in FIG. 3 being folded and the interlocking portion being inserted into and interlocked with the interlocking hole. In FIG. 4(a), the first area and the second area are completely folded, while in FIG. 4(b) the second area is slightly lifted from the first area.
The optical pickup 1 has a main body 2 made of zinc, a lens 3 that is disposed in the center of the main body 2, and a flexible printed board 4, as shown in FIGS. 1 and 2. The flexible printed board 4 is attached from the reverse side to the front side of the optical pickup 1. In FIG. 2, the arrow F shows the direction of the focus control, while the arrow T shows the direction of the tracking control. As shown in FIG. 3, reinforcing plates 5 are partially bonded to the reverse side of the flexible printed board 4. As shown in FIG. 1, a PDIC (hereinafter referred to as light-receiving IC) 6 is bonded to a specific location on the flexible printed board 4 on the front side of the main body 2 of the optical pickup 1, such that the light-receiving IC 6 is mounted to a specific location (light receiving location) on the front side of the main body 2 of the optical pickup 1 with an adhesive.
As shown in FIG. 3, the flexible printed board 4 mainly includes a first area 4a; a second area 4c which is folded to face the first area 4a when the flexible printed board 4 is attached to the rear side surface 2a of the main body 2; and a narrow belt-shape part 4e that extends out of the side of the first area 4a of the flexible printed board 4. The first area 4a is attached to the rear side surface 2a of the main body 2 via the front side (an example of the first side) of the second area 4c. A substantially circular interlocking hole 4b is formed at a specific location in the first area 4a of the flexible printed board 4. A substantially arrow-shaped interlocking portion 4d is formed unitarily with and protruding from the second area 4c. Furthermore, the light-receiving IC 6 is mounted on the front surface (the paper surface of FIG. 3, an example of the first side) of the distal portion 4g (an example of the attachment area), which is formed at the distal end of the narrow belt-shaped part 4e. In this embodiment, the flexible printed board 4 further includes a third area 4i, which has a distal portion 4h at the end to which a second IC 7 is bonded. The interlocking portion 4d is internally provided with a linear reinforcing pattern 4k. Furthermore, in this embodiment, the reinforcing plates 5 are bonded to the rear surface (the opposite surface of the paper surface of FIG. 3) of the first area 4a, the second area 4c, and the distal portions 4g and 4h. 
The first area 4a and the second area 4c of the flexible printed board 4 are bent by about 180 degrees at a border 4f shown in FIGS. 4(a) and 4(b), with the interlocking portion 4d of the second area 4c being inserted into and interlocked with a slight clearance into the interlocking hole 4b of the first area 4a. The narrow belt-shaped part 4e is bent at around a border 4j by about 90 degrees relative to the reinforcing plates 5. As shown in FIG. 4, the narrow belt-shaped part 4e is hung downward.
Then, at the end of the belt-shaped part 4e, the distal portion 4g is curvedly folded by about 180 degrees at a border 4h. Accordingly, the light-receiving IC 6 on the distal portion 4g is mounted at the light receiving location on the main body 2 of the optical pickup 1.
Here, the belt-shaped portion 4e is formed such that the distance D1 between the boarders 4j and 4h is longer than the sum of the length LD of the light-receiving IC 6, the thickness of the reinforcing plate 5, and the distance LE between the upper edge of the side surface of the main body 2 and the upper edge of the mounting hole 140. Accordingly, when the flexible printed board 4 is attached to the main body 2, there is formed a connecting portion 4m that is unitarily formed with the first area 4a and the distal portion 4g and connects the first area 4a and the distal portion 4g in a deflective manner. In this embodiment, as shown in FIG. 4, the connecting portion 4m connects the first area 4a with an end of the distal portion 4g that is farther from the rear side surface 2a of the main body 2.
Therefore, according to the first embodiment, since the flexible printed board 4 is provided with the connecting potion 4m that loosely connects the first area 4a and the distal portion 4g when the flexible printed board 4 is attached to the main body 2, minor adjustment of the position of the light-receiving IC 6 can be easily performed while the flexible printed board 4 is bent at the border 4j as well as at the border 4h. 
Furthermore, since the distal portion 4g is loosely connected to the first area 4a via the flexed portion 4m, the load applied to the adhesive that attaches the light-receiving IC 6 to the attaching portion of the main body 2 can be lightened once the flexible printed board 4 is attached to the main body 2.
Furthermore, since the interlocking portion 4d interlocks with the interlocking hole 4b, the first and second areas 4a and 4c are folded with a clearance therebetween, as shown in FIG. 4(b). Accordingly, the position of the distal portion 4g of the flexible printed board 4 relative to the attachment portion of the main body 2 can be adjusted even more easily.
Still furthermore, the interlocking portion 4d of the second area 4c is formed in a substantially arrow shape. Thus, the interlocking portion 4d can be easily inserted into the interlocking hole 4b of the first area 4a and remain inserted. In other words, the interlocking portion 4d can be prevented from being inadvertently removed. The interlocking portion 4d can also be prevented from bending because the interlocking portion 4d is provided with the linear reinforcing pattern 4k. 
ALTERNATIVE EMBODIMENTS
Referring now to FIGS. 5-6, the flexible printed board mounting structure in accordance with alternative embodiments will now be explained. In view of the similarity between the first and alternative embodiments, the parts of the alternative embodiments that are identical to the parts of the first embodiment will be given the same reference numerals as the parts of the first embodiment. Moreover, the descriptions of the parts of the alternative embodiments that are identical to the parts of the first embodiment may be omitted for the sake of brevity. The parts of the alternative embodiments that differ from the parts of the first embodiment will be indicated with a prime (′) and a double prime (′′).
FIG. 5 is a projection of the flexible printed board 4′ for use in a flexible printed board mounting structure in accordance with the second embodiment of the present invention.
The flexible printed board 4′ of the second embodiment is different from the flexible printed board 4 of the first embodiment only in that the interlocking hole 4b′ is provided as a rectangular hole that is oriented at an angle about 180 degrees turned relative to the interlocking portion 4d′, as shown in FIG. 5. Also, the interlocking portion 4d is formed in a substantially cross shape. In the second embodiment, the substantially cross-shaped interlocking portion 4d′ interlocks with the rectangular interlocking hole 4b′ by twisting the interlocking portion 4d′. Once the interlocking portion 4d′ is interlocked with the interlocking hole 4b, and the interlocking portion 4d′ is returned to its original state, whereupon the interlocking portion 4d′ remains interlocked with the interlocking hole 4b′ in an intersecting manner.
Therefore, according to the second embodiment, since the interlocking portion 4d′ is formed in a substantial cross shape, it can be easily inserted into and interlocked with the rectangular interlocking hole 4b′ and can keep the interlocked state.
FIG. 6 is a projection of the flexible printed board 4′′ for use in a flexible printed board mounting structure in accordance with the third embodiment.
The flexible printed board 4′′ is different from the flexible printed board 4 of the first embodiment only in that the interlocking hole 4b′′ is formed as a substantially L-shaped slot that opens to an edge of the first area 4a′′. The interlocking portion 4d′′ is formed in a substantially T shape. The interlocking portion 4d′′ is twisted to be inserted sideways into the interlocking hole 4b′′ from the base portion of the L-shaped slot. Then, the interlocking portion 4d′′ remains interlocked in the bent portion of the L-shaped interlocking hole 4b′′, with the interlocking portion 4d′′ being at an angle of about 90 degrees relative to the bent portion of the L-shaped interlocking hole 4b′′. 
According to the third embodiment, the interlocking portion 4d′′ can be easily inserted into the substantially L-shaped interlocking hole 4b from the edge. Then, the interlocking portion 4d′′ remains interlocked in the bent portion of the interlocking hole 4b. Such interlocking structure can be achieved with the interlocking portion 4d′′, which has a simple shape.
Furthermore, the shapes of the interlocking hole and the interlocking portion are not limited to the shapes disclosed in the above-described embodiments. The interlocking hole and the interlocking portion may take other shapes as long as their shapes allow interlocking between the interlocking portion and the interlocking hole.
As used herein, the following directional terms “forward, rearward, above, downward, vertical, horizontal, below and transverse” as well as any other similar directional terms refer to those directions of a device equipped with the present invention. Accordingly, these terms, as utilized to describe the present invention should be interpreted relative to a device equipped with the present invention.
The term “configured” as used herein to describe a component, section or part of a device includes hardware and/or software that is constructed and/or programmed to carry out the desired function.
Moreover, terms that are expressed as “means-plus function” in the claims should include any structure that can be utilized to carry out the function of that part of the present invention.
The terms of degree such as “substantially”, “about” and “approximately” as used herein mean a reasonable amount of deviation of the modified term such that the end result is not significantly changed. For example, these terms can be construed as including a deviation of at least ±5% of the modified term if this deviation would not negate the meaning of the word it modifies.
This application claims priority to Japanese Patent Application No. 2004-132702. The entire disclosure of Japanese Patent Application No. 2004-132702 is hereby incorporated herein by reference.
While only selected embodiments have been chosen to illustrate the present invention, it will be apparent to those skilled in the art from this disclosure that various changes and modifications can be made herein without departing from the scope of the invention as defined in the appended claims. Furthermore, the foregoing descriptions of the embodiments according to the present invention are provided for illustration only, and not for the purpose of limiting the invention as defined by the appended claims and their equivalents. Thus, the scope of the invention is not limited to the disclosed embodiments.

## Claims

1. A flexible printed board mounting structure, comprising:
a main body having a front side surface, a rear side surface, and an attachment portion that is on the rear side surface, a surface of the attachment portion being substantially perpendicular to the rear side surface; and
a flexible printed board attached to at least the rear side surface and the attachment portion of the main body, the flexible printed board having
a first area that is at least partially attached to the rear side surface of the main body,
an attachment area to which a light-receiving IC is attached, the attachment area being attached to the attachment portion of the main body, and
a connecting portion that is unitarily formed with the first area at one side of the connecting portion and the attachment area at the other side of the connecting portion and connects the first area and the attachment area in a deflective manner, a length between the one side and the other side along the connecting portion being longer than a length of a short side of the light-receiving IC.

2. The flexible printed board mounting structure according to claim 1, wherein
the flexible printed board further includes
a second area that is folded to face the first area, and
an interlocking portion formed unitarily with the second area, and

the first area has an interlocking hole formed thereon, the interlocking portion interlocking with the interlocking hole.

3. The flexible printed board mounting structure according to claim 2, wherein
the interlocking portion is substantially arrow-shaped.

4. The flexible printed board mounting structure according to claim 2, wherein
the interlocking hole is an elongated hole that extends in a first direction, and
the interlocking portion has a portion that extends in a second direction, the second direction intersecting with the first direction.

5. The flexible printed board mounting structure according to claim 2, wherein
the interlocking hole is a L-shaped slot that opens to an edge of the first area.

6. The flexible printed board mounting structure according to claim 2, wherein
the first area is attached to the rear side surface of the main body via a first side of the second area, and
the light-receiving IC is attached to the first side of the attachment area.

7. The flexible printed board mounting structure according to claim 4, wherein
the interlocking portion is substantially cross-shaped.

8. The flexible printed board mounting structure according to claim 5, wherein
the interlocking portion is substantially T-shaped.

9. A flexible printed board mounting structure, comprising:
a main body having a front side surface, a rear side surface, and an attachment portion that is on the rear side surface, a surface of the attachment portion being substantially perpendicular to the rear side surface; and
a flexible printed board attached to at least the rear side surface and the attachment portion of the main body, the flexible printed board having
a first area that is at least partially attached to the rear side surface of the main body,
an attachment area to which a light-receiving IC is attached, the attachment area being attached to the attachment portion of the main body, and
a connecting portion that is unitarily formed with the first area and the attachment area and connects the first area and the attachment area in a deflective manner, the connecting portion connecting the first area with an end of the attachment area that is farther from the rear side surface of the main body.

10. An optical pick up, comprising:
an objective lens;
a main body having a front side surface on which the objective lens is provided, a rear side surface, and an attachment portion that is on the rear side surface, a surface of the attachment portion being substantially perpendicular to the front and rear side surfaces; and
a flexible printed board attached to at least the rear side surface and the attachment portion of the main body, the flexible printed board having
a first area having an interlocking hole formed thereon,
a second area that is folded to face the first area, the first area being at least partially attached to the rear side surface of the main body via a first side of the second area,
an attachment area to which the first side of which a light-receiving IC is attached, the attachment area being attached to the attachment portion of the main body,
a connecting portion that is unitarily formed with the first area and the attachment area and connects in a deflective manner the first area and an end of the attachment area that is farther from the rear side surface of the main body, and
an interlocking portion formed unitarily with the second area, the interlocking portion interlocking with the interlocking hole.

11. The optical pick up according to claim 10, wherein the interlocking portion is substantially arrow-shaped.

12. The optical pick up according to claim 10, wherein
the interlocking hole is an elongated hole that extends in a first direction, and
the interlocking portion has a portion that extends in a second direction, the second direction intersecting with the first direction.

13. The optical pick up according to claim 10, wherein
the interlocking hole is a L-shaped slot that opens to an edge of the first area.

14. The optical pick up according to claim 12, wherein
the interlocking portion is substantially cross-shaped.

15. The optical pick up according to claim 13 , wherein
the interlocking portion is substantially T-shaped.