JPH064602Y2 - Flexible circuit board for tubular electronic devices - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial field of application] The present invention relates to a flexible circuit board used in a tubular electronic device such as an interchangeable lens of a single-lens reflex camera.

[Conventional technology]

In recent years, single-lens reflex cameras equipped with an autofocus mechanism have been widely used. An example of such a camera is shown in FIG. In FIG. 4, 1 is a camera body, 2 is an interchangeable lens having a tubular shape that is detachably attached to the camera body, and 3 is, for example, a lens 4 via a drive mechanism (not shown).
Is a motor for moving the lens to the in-focus position. Such an interchangeable lens 2 requires a complicated electronic circuit for connecting the drive circuit in the camera body 1 to the motor 3, etc., and itself constitutes a cylindrical electronic device. However, in such an interchangeable lens, the flexible circuit board 5 is usually built in for high-density mounting in a narrow space.

Such a flexible printed circuit board 5 is shown in FIG. As shown in FIG. 5 (a), the flexible printed circuit board 5 is formed of a flat plate-like main body having a substantially strip shape and a substantially rectangular shape in a plan view, and terminals or other flexible cables (not shown) are provided on both ends of the upper portion thereof. It has arms 5a and 5b connected to the circuit board. The flexible printed circuit board 5 has an upper edge 5 which is slightly below the central portion thereof.
A substantially rectangular through hole 6 that is substantially parallel to c is provided.

The flexible printed circuit board 5 is the interchangeable lens 2
When attached to, it is bent upward as shown in FIG. 5 (b) with the straight line overlapping the through hole as a boundary,
Next, the above straight line is bent in an arc shape so as to follow the circumference of the interchangeable lens 2, and is attached around the interchangeable lens 2.

[Problems to be solved by the invention]

In the conventional flexible printed circuit board 5 as described above, the length of the lower edge and the length of the upper edge of the substantially rectangular through hole 6 formed substantially parallel to the end edge 5c are equal, and the through hole 6 is formed. When bent as shown in FIG. 5 (b) with a straight line that overlaps with, the one side surface 51 and the other side surface 52 have the same longitudinal dimension. When the flexible printed circuit board 5 bent in this manner is curved in an arc shape so that the side surface 51 is located inside and along the circumference of the interchangeable lens 2, the length of the inner side surface 51 and the outer side surface 52 is increased. Since the dimensions in the directions are the same, as shown in FIG. 5 (c), the inner side surface 51 is unnecessarily deflected and is not curved so as to fit exactly along the circumference of the interchangeable lens 2. Furthermore, as shown in FIG. 5 (b), stress is concentrated in the bent portions 53 and 54 when bent, cracks occur, and in the worst case, the flexible printed circuit board is damaged. The problem arises.

[Purpose of device]

The present invention solves the above-mentioned problems in the conventional flexible circuit board for a cylindrical electronic device, and can be easily arranged along the circumference of the cylinder without causing a crack or a break in the bent portion. An object of the present invention is to provide a flexible printed circuit board for a tubular electronic device.

[Outline of device]

A flexible circuit board for a tubular electronic device according to the present invention has a through-hole having a substantially long hole formed on a bending line of a flat-plate flexible circuit board main body, and is bent at the bending line overlapping with the through hole as a boundary. In a flexible circuit board for a cylindrical electronic device, which is curved in an arc shape along the circumference of the cylindrical electronic device, the edge of the through hole located outside when curved in the arc shape is located inside It is characterized in that it is formed in a substantially arc shape so as to be longer than the length of the edge of the through hole.

〔Example〕

 Embodiments shown in the drawings will be described below.

1 (a) to (c) show a first embodiment of a flexible circuit board according to the present invention. In FIG. 1, parts similar to those of the conventional example shown in FIG. 5 are designated by the same reference numerals, and detailed description thereof will be omitted.

The flexible circuit board 5 shown in FIG. 1 is a flat flexible circuit board body having a through-hole 60 in the form of an elongated hole substantially parallel to the upper edge 5c thereof, and is shown in FIG. 1 (b). As shown in FIG. 1 (c), it is bent along a straight line that overlaps the through hole 60, and then along the circumference of the interchangeable lens.
As shown in FIG.

In this embodiment, the upper edge 60a of the through hole 60 is linear, but the lower edge 60b of the through hole 60 is formed longer than the upper edge 60a and is curved in a substantially arc shape. Further, the lower end edge 5d of the flexible printed circuit board 5 is not parallel to the upper end edge 5c, and is formed such that its substantially central portion projects downward. In the illustrated example, the lower end edge 5d is formed in an arc shape substantially parallel to the lower edge 60b of the through hole 60.

Next, a case where the flexible printed circuit board 5 shown in FIG. 1 configured as described above is mounted on a tubular electronic device such as an interchangeable lens of a single lens reflex camera will be described. First, the lower edge 6 of the through hole 60 as shown by the one-dot chain line in FIG.
Tangent line h of both ends of 0b, a fold line having a substantially parallel inclination
_The flexible printed circuit board 5 is bent upward at the boundaries ₁ and ₂ as shown in FIG. 1 (b). At this time, since the longitudinal dimension of the outer side surface 502 is slightly longer than the inner side surface 501, the outer side surface 502 is slightly bent. Finally, as shown in FIG. 1 (c), it may be bent in an arc shape along the circumference of the tubular electronic device. With this, the outer side surface 502 is not bent, and the inner side surface 501 and the outer side surface 502 can be bent without difficulty with substantially the same radius of curvature. Therefore, stress is not concentrated on the bent portions 503 and 504, and cracks and damages do not occur.

Although the present invention is applied to the interchangeable lens of the single-lens reflex camera in the above-described embodiments, the present invention is not limited to this and can be widely applied to other cylindrical electronic devices.

FIG. 2 shows another embodiment of the present invention. In this example,
The flexible printed circuit board 5 is provided with through holes 600 in the shape of an elongated hole as described above. Also in this embodiment, when the flexible printed circuit board is bent into an arc shape, the length of the through hole lower edge 600b located outside thereof is the upper edge 6.
Although it is formed longer than 00a, the lower edge 600b of the through hole 600 in this embodiment is substantially parallel to the upper edge 600a.
The lower edge 600b has a shape that approximates an arc shape by projecting downward as a whole, and the lower edge 600b is closer to the upper edge 600a than the upper edge 600a. It's getting longer.

FIG. 3 shows another embodiment of the present invention, which is a lower edge 600 of the through hole 6000 of the flexible printed circuit board.
Reference numeral 0b is an extension similar to the lower edge 600b in the embodiment shown in FIG. 2 and has an arc shape similar to that of the extension edge 6000c, 6000 extending substantially upward at both longitudinal ends thereof.
c is integrally provided. Providing the extension in this manner makes it easier to bend the flexible printed circuit board without difficulty. In the illustrated embodiment, the extension 6
000c is inclined inward, but it is not always necessary to incline in this way.

[Effect of device]

As described above, according to the present invention, a substantially elongated hole-shaped through hole is formed on a bending line of a flat plate-shaped flexible circuit board body, and after bending at the bending line overlapping with the through hole, a cylindrical shape is formed. In a flexible circuit board for a cylindrical electronic device, which is curved in an arc shape along the circumference of an electronic device, an edge of the through hole located outside when curved in an arc shape, the through hole located inside It is possible to easily arrange along the circumference of the tubular electronic device by the simple improvement that it is formed in a substantially arc shape so that it is longer than the length of the edge, and cracks or damage occur at the bent part. Since it is possible to construct a wiring structure for a cylindrical electronic device without doing so, it is extremely practical.

[Brief description of drawings]

FIG. 1 shows an embodiment of a flexible circuit board according to the present invention. (A) is a plan view of the flexible printed circuit board, (b) is a perspective view showing its bent state, and (c) is a cylindrical shape. FIG. 2 is a perspective view showing a curved state, FIG. 2 is a plan view showing another embodiment of the flexible printed circuit board according to the present invention, and FIG.
The drawing is a plan view showing still another embodiment of the present invention. FIG. 4 is a perspective view of a camera to which the present invention is applied, FIG. 5 is a view showing a conventional flexible printed circuit board used in the camera shown in FIG. 4, (a) is a plan view, and (b) is a plan view. () Is a perspective view showing the bent state, and (c) is a perspective view showing the bent state. 2 ... Interchangeable lens (cylindrical electronic device) 5 ... Flexible printed circuit board 6, 60, 600, 6000 ... Through hole 60a, 600a, 6000a ... Upper edge 60b, 600b, 6000b ... Lower edge

 ─────────────────────────────────────────────────── ───Continued from the front page (56) References Shown 60-106366 (JP, U) Shown 58-103182 (JP, U) Shown 60-42753 (JP, U)

Claims (1)

[Scope of utility model registration request] 1. A substantially circular through hole is formed on a bending line of a flat plate-shaped flexible circuit board main body, and after bending at the bending line overlapping the through hole, the circumference of a cylindrical electronic device is defined. In a flexible circuit board for a cylindrical electronic device which is curved in an arc shape so as to follow, the edge of the through hole located outside when curved in an arc shape is defined by the length of the edge of the through hole located inside. A flexible circuit board for a cylindrical electronic device, which is formed in a substantially arc shape so as to be long.