JPH0650198Y2 - Linear light source - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (a) Field of Industrial Application The present invention relates to a linear light source using a light emitting diode and a rod lens suitable for a document reader and the like.

(B) Conventional technology A linear light source using a light emitting diode and a rod-shaped lens instead of a fluorescent lamp or a xenon tube centering on a document reader (so-called contact type image sensor) used in a copying machine or a document making machine in recent years. Came to be used. Such a linear light source is disclosed in, for example, Japanese Patent Laid-Open No. 60-230626.
As shown in the figure, the reflector (3) for fixing the rod-shaped lens (40) to the long substrate (10) on which the light emitting diodes (20) (20) are placed.
0) is provided.

However, the rod-shaped lens (40) is, for example, a glass or resin-molded product having a diameter of 3 to 8 mm, but has a short focus, while the light emitting diodes (20) (20) ... Generate heat by lighting and the heat causes the substrate (10). The support frame (not shown) thermally expands, but the reflective frame (30) is fixed to the substrate (10), and the reflective frame (30) and the rod lens (40) are as wide as the substrate (10). Does not thermally expand, the substrate (10) is likely to warp. For this reason, especially in the central part, the distance between the rod-shaped lens (40) and the light emitting diodes (20) (20) ... Is too large, and the illuminance and the illumination width at the illumination position fluctuate greatly, which is inconvenient.

Further, the reflecting frame (30) is long and thin with a height of 5 to 10 mm and a length of 200 to 600 mm, so that the resin is likely to warp during resin molding. The warp in the vertical direction has the same drawbacks as the above-mentioned warp due to thermal expansion, and the warp in the left / right direction is the warp of the side wall reflecting surface, which is inconvenient because the linearity is impaired at the illumination position. Therefore, the reflecting frame (30) was molded by dividing it into an appropriate length, but the arrangement pitch of the light emitting diodes was as short as 1.5 to 4 mm, which was not preferable because light leaked from the joint of the reflecting frame.

(C) Problems to be Solved by the Invention The present invention has been made in consideration of the above points, and provides a linear light source using a long substrate and having a reflective plate that does not easily warp.

(D) Means for Solving the Problems The present invention provides a side wall that extends substantially linearly along both sides of a rod-shaped lens as the above-mentioned reflection frame, and a protrusion is provided inside the side wall. More preferably, streak-shaped projections smaller than the projections are provided between the projections along the reflection frame longitudinal direction.

(E) Action As a result, the protrusion is integrated so as to wrap around the rod-shaped lens, and since the side wall is approximately straight, it is difficult to project the protrusion outward, so the rod-shaped lens itself is supported to prevent warpage. It acts as a member and effectively prevents warpage that causes defocusing. Further, since the streaky protrusions correct the bending of the side surface covering wall, they function to keep the side surface covering wall straight even after molding.

(H) Embodiment FIG. 1 and FIG. 2 are sectional views of a linear light source of an embodiment of the present invention.
(1) is a substrate such as a glass epoxy substrate, for example, width 16mm
The length is 238 mm, the thickness is 0.8 mm, and the length is long so as to correspond to the width of a document or the like, and long holes (11) (11) having a long axis are provided in the longitudinal direction. (2) (2) ... are light emitting diodes which are arranged in a line in the longitudinal direction of the substrate (1) and are wired by a wire bonding method or the like, and are made of GaP or GaAsP, and have a basic pitch, for example. Aligned at 2.5mm. (3) is inserted into the reflecting surfaces (31) (31) (32) (32) ... Surrounding the light emitting diodes (2) (2) ... And the long holes (11) (11) ... of the substrate (1). A reflection frame having fixed pins (33) (33) with crushed tips and fixed frames (34) (34) for rod-shaped lenses, which is made of a white resin molded product. The edge portions of the reflecting surfaces (31) (31) have side surface covering walls (311) (311) linearly extending in the longitudinal direction, and a plurality of protrusions (312) (312) are provided inside thereof. ... is provided. And more preferably, as shown in FIGS. 1 and 3, streak (313) (313)
Are provided between the protrusions (312) (312) ... along the longitudinal direction. (4) is the fixed frame (34) (3) of the reflective frame (3)
A cylindrical or elliptic rod-shaped lens locked and fixed in 4), made of glass or the like, and provided with a ridge direction in a direction coinciding with the rows of the light emitting diodes (2) (2). .

The above configuration will be described more specifically. Board (1)
The long holes (11) (11) of, for example, have a short diameter of 1.2 mm and a long diameter of 1.6 to 1.8 m.
It has a substantially elliptical shape of m, and the fixing pins (33) (3
3) has a diameter of 1.0 mm and a length of 2.5 mm, and more preferably, a stepped portion is provided at a height approximately equal to the thickness of the substrate to make it taper to ensure welding and fixing. The reflection frame (3) is provided with fixing frames (34) and (34) at a position 3.25 mm from the bottom surface (top surface of the substrate) so that the center of the rod-shaped lens (4) having a diameter of 5.0 mm is located. The height of (311) and (311) is 4.1mm
It is provided at the position. Then, above the center position of the rod-shaped lens (4), width 0.6-0.8 mm length 3-5 mm thickness 0.1-
Protrusions (312) and (312) of 0.3 mm are provided and abutted on the side surface of the rod-shaped lens (4).

As a method of providing a protrusion so as to wrap the rod-shaped lens (4), the tongue portions (314) (314) having protrusions (313) (313) ... There is a way to make it protrude. Since this can utilize the tightening of the rod-shaped lens (40) by the elasticity of the tongue pieces (314) (314) ..., the effect is great especially when the protrusions (313) (313) are large, but like the present invention. It is not preferable for the reflective frame of the linear light source. This is because in the present invention, when the protrusions (312) and (312) are enlarged, a gap is created between the reflecting surfaces (31) and (31) and the rod-shaped lens, and light leakage easily occurs. It is desirable not to provide irregularities or large protrusions on the outer shape because it is easy to be restricted by mounting such as passing through the vicinity of the reflection frame and entering the light receiver, and the main purpose of providing protrusions (312) (312) Is not the fixing of the rod-shaped lens (4) in this application, but the substrate (1)
This is because the rod-shaped lens (4) serves as a warp preventing support member for the reflection frame (3) against the warp of the side wall (311).
This is because it is necessary to increase the resistance of the reflection frame (3) to bending by extending the (311) linearly. It is effective to arrange such protrusions (312) (312) at intervals of 25 to 60 mm along the side surface covering walls (311) (311).

Further, when the reflecting frame (3) is integrally molded, it is slender and thus easily warped, and in particular, by providing the protrusions (312) and (312), it is easy to warp in the left-right direction (the thickness direction of the reflecting surfaces (31) and (31)).
Therefore, parallel to the side wall (311) (311), the streak (31
3) By providing (313), this warp could be prevented and corrected. The streaks (313) (313) may have a height of 0.03 to 0.10 mm and may have parallel recesses. Although it may be provided over the entire length, since the protrusions (312) (312) themselves serve to prevent warpage, it is effective to provide only between the protrusions (312) (312).

(G) Effect of the Invention As described above, in the present invention, since the plurality of protrusions provided inside the side wall of the reflection frame partially abut the rod-shaped lens, the side wall has elasticity. It becomes easier to follow the rod-shaped lens. Therefore, the rod-shaped lens itself serves as a warp-preventing support member, and the horizontal warp of the reflection frame is reduced. As a result, the distance between the light emitting diode and the reflecting surface of the reflecting frame is maintained substantially constant, so that the linearity of the light image is improved in the illuminating device located above the rod-shaped lens.

[Brief description of drawings]

1 and 2 are sectional views of a linear light source according to an embodiment of the present invention, FIG. 3 is an enlarged view of a main part thereof, and FIG. 4 is a sectional view of a conventional linear light source. (1) ... Substrate, (2) (2) ... Light emitting diode, (3)
... Reflecting frame, (4) ... Rod-shaped lens, (312) (312) ... Protrusion, (313) (313) ... Streaky projection.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (56) Reference JP-A-59-128531 (JP, A) Actual opening 61-62465 (JP, U) Actual opening 60-36612 (JP, U)

Claims (2)

[Scope of utility model registration request] 1. A fixed substrate having a long substrate, a plurality of light emitting diodes mounted on the substrate aligned in the longitudinal direction, and a reflecting surface surrounding the light emitting diodes. A reflecting plate and a substantially cylindrical rod-shaped lens fixed to the reflection frame by arranging a ridge direction in a direction substantially corresponding to the row of the light-emitting diodes are provided, and the reflection frame is provided along both sides of the rod-shaped lens. A linear light source having a side wall covering a substantially straight line, and having a plurality of protrusions abutting the rod-shaped lens inside the side wall. 2. A utility model registration claim, wherein streak-shaped projections smaller than the projections are provided inside the side wall of the reflection frame along the longitudinal direction between the projections. The linear light source according to item 1.