Radiant energy – Photocells; circuits and apparatus – Photocell controlled circuit
Reexamination Certificate
1998-07-30
2001-07-10
Lee, John R. (Department: 2878)
Radiant energy
Photocells; circuits and apparatus
Photocell controlled circuit
C250S216000, C250S227200, C362S026000, C385S046000
Reexamination Certificate
active
06259082
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to an image reading apparatus. The present invention also relates to a light-leading member advantageously used in an image reading apparatus.
2. Description of the Related Art
An example of conventional image reading apparatus is disclosed in JP-A-6-217084. Referring to
FIGS. 38 and 39
of the accompanying drawings, the conventional image reading apparatus (Ae) includes a lighting unit B accommodated in a housing
4
e
for illuminating a document paper sheet K, a glass plate
91
supported by the housing
4
e
, and a lens array
51
e
for focusing image-carrying reflection light coming from a reading section
90
of the image reading apparatus Ae. The image reading apparatus Ae also includes a plurality of image sensor chips
52
e
(only one is shown) mounted on a printed circuit board
6
e.
As best shown in
FIG. 39
, the conventional lighting unit B includes a transparent, elongated light-leading member
1
e
and a light source
2
e
such as an LED (light emitting diode) carried by an additional printed circuit board
92
. The light-leading member
1
e
includes an upper surface
12
e
, a lower surfaces
14
e
opposite to the upper surface
12
e
, two end surface
15
e
-
16
e
, and so forth. The upper surface
12
e
is directed toward the reading section
90
.
The light source
2
e
is arranged in facing relation to the end surface
15
e
. Thus, the light rays emitted from the light source
2
e
enter the light-leading member
1
e
at the end surface
15
e
to propagate through the light-leading member
1
e
toward the other end surface
16
e
. The light rays within the light-leading member
1
e
may be internally reflected several times by the upper surface
12
e
, the lower surface
14
e
and so forth, before the light rays come out through the upper surface
12
e
for illuminating the document paper sheet K.
The conventional image reading apparatus Ae has been found disadvantageous in the following points.
As stated above, two separate printed circuit boards (
6
e
and
92
) are used for the conventional image reading apparatus Ae. This means that it is necessary to form wiring patterns separately for the two circuit boards
6
e
and
92
, which is time-consuming. In addition, the housing
4
e
should be arranged to accommodate the two circuit boards
6
e
and
92
at different positions. Such an arrangement may make the manufacturing of the housing
4
e
complicated.
Further, as shown in
FIG. 38
, side surfaces of the light-leading member
1
e
are exposed (i.e., the side surfaces are not covered by inner portions of the housing
4
e
or any other additional element.) Due to this arrangement, part of light propagating through the light-leading member
1
e
will unduly come out from the side surfaces, but not be used for illuminating the document paper sheet K.
Still further, even if the light propagating through the light-leading member
1
e
comes out through the upper surface
12
e
, the light may be directed in other directions but not toward the reading section
90
.
SUMMARY OF THE INVENTION
It is therefore an object of the present invention to provide an image reading apparatus wherein light emitted from a light source is effectively directed toward a reading section for a document paper sheet to be read out, thereby overcoming the disadvantages described above.
Another object of the present invention is to provide an image reading apparatus which is easily manufactured.
A further object of the present invention is to provide a light conductor which is advantageously used in an image reading apparatus.
According to a first aspect of the present invention, there is provided a light conductor comprising an elongated light-leading member for propagation of light, the light-leading member being provided with a head surface, a bottom surface, a first side surface and a second side surface, the first and second side surfaces extending between the head surface and the bottom surface,
wherein at least one of the first and the second side surfaces regulates directions of light rays propagating through the light-leading member toward the head surface.
Preferably, the light conductor further comprises reflecting means for covering said at least one of the firs and the second side surfaces.
The reflecting means may comprise an elongated reflection member made of a white, reflective resin material, or reflective sheet.
Preferably, the light-leading member and the reflecting means may be positionally secured to each other by engaging means.
According to a preferred embodiment, the light-leading member has an asymmetric cross section. In such an instance, the first side surface may comprise an inclined portion overhanging the bottom surface. The asymmetric cross section may be pentagonal.
According to another preferred embodiment, said at least one of the first and second side surfaces extends, in cross-section, along a parabola.
According to still another preferred embodiment, said at least one of the first and second side surfaces extends, in cross-section, along an ellipse.
According to a second aspect of the present invention, there is provided a light equipment used in an image reader comprising:
a light source;
an elongated light-leading member for propagation of light emitted from the light source, the light-leading member being provided with a head surface, a bottom surface, a first side surface and a second side surface, the first and second side surfaces extending between the head surface and the bottom surface; and
reflecting means for covering at least one of the first and the second side surfaces.
Preferably, the light source is arranged in facing relation to the bottom surface.
Preferably, the light-leading member includes a light-guiding section which is provided with a reflection surface, so that light emitted from the light source in a direction perpendicular to a longitudinal direction of the light-leading member is reflected by the reflection surface in the longitudinal direction of the light-leading member.
According to a third aspect of the present invention, there is provided an image reading apparatus comprising:
a light source for irradiating a document sheet with light;
an elongated light-leading member for propagation of light emitted from the light source, the light-leading member being provided with a head surface, a bottom surface, a first side surface and a second side surface, the first and second side surfaces extending between the head surface and the bottom surface;
a row of image sensor chips for detecting light reflected on the document sheet; and
an insulating circuit board for carrying the image sensor chips;
wherein the light source is mounted on the circuit board together with the image sensor chips.
The head surface may be smaller in cross-section dimension than the bottom surface.
At least one of the first and second side surfaces may extend, in cross-section, along a parabola. In such an instance, the bottom surface is arranged adjacent to a focus of the parabola.
Alternatively, at least one of the first and second side surfaces may extend, in cross-section, along an ellipse. In such an instance, the bottom surface is arranged adjacent to a focus of the ellipse.
Other features and advantages of the present invention should become clear from the detailed description to be made hereinafter referring to the accompanied drawings.
REFERENCES:
patent: 4714983 (1987-12-01), Lang
patent: 5070431 (1991-12-01), Kitazawa et al.
patent: 5295047 (1994-03-01), Windross
patent: 5499112 (1996-03-01), Kawai et al.
patent: 5959740 (1999-09-01), Takeda et al.
patent: 6-217084 (1994-08-01), None
Fujimoto Hisayoshi
Imamura Norihiro
Onishi Hiroaki
Takakura Toshihiko
Lee John R.
Merchant & Gould P.C.
Rohm & Co., Ltd.
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