Optical: systems and elements – Single channel simultaneously to or from plural channels – By surface composed of lenticular elements
Reexamination Certificate
2001-09-27
2004-02-17
Epps, Georgia (Department: 2873)
Optical: systems and elements
Single channel simultaneously to or from plural channels
By surface composed of lenticular elements
C359S623000
Reexamination Certificate
active
06693748
ABSTRACT:
TECHNICAL FIELD
The present invention relates to a lens array unit utilized in e.g. an image reading device. Further, the present invention relates to a method of manufacturing a lens array as part of the lens array unit, and to an optical device incorporating the lens array unit.
BACKGROUND ART
In an image reading device incorporated in a facsimile machine or a scanner, often, an image of the document is read without inversion nor magnification, by utilizing a plurality of light receiving elements disposed in a row. In this arrangement, the image of the document must be focused on the light receiving elements without inversion nor magnification, by utilizing a lens array provided by a plurality of image formation lenses. Conventionally for example, this is achieved by a lens array
9
as shown in FIG.
51
and
FIG. 52
, in which a plurality of lenses
91
are held by a resin support
90
.
The lenses
91
are provided by a plurality of columnar selfoc lenses (rod lenses), each having a pair of flat lens surfaces
91
a
,
91
b
. However, each lens
91
has a unique optical characteristic that its refractive index varies in accordance with the distance from its axial center. As a result, as shown in
FIG. 52
, light which passes through the lens
91
takes a snaky route, and an object (a→b) is projected in an non-inverted, non-magnified image (a′→b′).
In the prior art, in order to manufacture the lens array
9
, the lenses
91
are manufactured first. Next, by means of an insertion molding, the lenses
91
are embedded into the support
90
when the support is molded from resin.
However, the prior art has the following problem.
Specifically, first, since the lens
91
is a selfoc lens which has the unique optical characteristic as described above, manufacturing the lens is not an easy task. Without a special facility for making the selfoc lens, manufacture of the lens
91
is very difficult, which has increased manufacturing cost of the lens array
9
.
Further, according to the above prior art, manufacturing of the lenses
91
is a separate process from the forming of the support
90
. Thus, production efficiency of the lens array
9
has been low, increasing further the manufacturing cost of the lens array
9
.
DISCLOSURE OF THE INVENTION
An object of the present invention is to provide a lens array unit and an optical device using the same, capable of eliminating or reducing the problems described above.
Another object of the present invention is to provide a method for appropriately manufacturing the lens array as a component part of the lens array unit.
A lens array unit provided by a first aspect of the present invention comprises: a first lens array including a plurality of first lenses each serving as a convex lens, and a first support holding the first lenses. The first lenses and the first support are formed integrally of a translucent resin. The lens array unit further comprises a second lens array including a plurality of second lenses each serving as a convex lens, and a second support holding the second lenses. The second lenses and the second support are formed integrally of a translucent resin. The first and the second lens arrays are placed, one on the other, with each of the first lenses in alignment with a corresponding one of the second lenses on a same axis, for formation of a non-inverted, non-magnified image.
The lens array unit having such an arrangement can be suitably used as a replacement of the prior art selfoc lens array, for application of forming a non-inverted, non-magnified image. Since each of the first and the second lenses is provided by a convex lens, unlike the selfoc lens, there is no need to vary the refractive index inside the lens. According to the present invention, each of the lenses in the first and the second lens arrays and the supports therefor can be easily formed by means of an ordinary resin injection molding technique. As a result, production efficiency of the lens array unit according to the present invention is high, making it possible to lower a cost of manufacture than in the lens array unit that uses the prior art selfoc lens.
Preferably, at least the first lens array, of the first and the second lens arrays, is provided with separating means for optical separation of the lenses from each other.
According to such an arrangement, it becomes possible to prevent a problematic crossing of light (optical cross talk) between the first lenses when the light passes through the first lens array. This makes it possible to form a clear image. When using the lens array unit according to the present invention, if an arrangement is made so that the light will first enter the first lens array, comes out of the first lens array and then enters the second lens array, the optical cross talk in the second lens array can be reduced to a certain extent even if the second lens array is not provided with the separating means, and this is already demonstrated.
Preferably, the separating means is provided only in the first lens array.
According to such an arrangement, manufacture of the lens array unit can be facilitated to the extent that the second lens array is not provided with the separating means.
Preferably, the separating means includes a light shield isolating the first lenses from each other.
According to such an arrangement, the light shield appropriately prevents the light from crossing each other between the first lenses.
Preferably, the light shield is capable of absorbing light received.
According to such an arrangement, it becomes possible to prevent light which has reached the light shield from being reflected back by the light shield, making it more desirable for forming a clear image.
Preferably, the light shield includes at least one recess provided in the first support for the isolation of the first lenses from each other.
According to such an arrangement, it becomes possible to prevent light from traveling between the first lenses, by the recess or the surface that defines the recess.
Preferably, the light shield further includes a dark material covering the surface which defines the recess. The word dark herein means a black color preferably, although this does not necessarily limit the present invention.
According to such an arrangement, the dark material appropriately blocks and absorbs the light which otherwise will get out of the first lens and then into an adjacent one.
Preferably, the first support includes a first surface, and a second surface away from the first surface at a distance in a direction of the axis's of the first lenses and faced to the second lens array. Further, the recess is provided in at least one of the first and the second surfaces, without penetrating the first support.
Preferably, the recess is provided in each of the first and the second surfaces.
According to such an arrangement, even if the depth of the recess is relatively shallow, it is still possible to sufficiently prevent the optical cross talk between the first lenses. Therefore, the present arrangement is suitable when the recess cannot be made very deep.
Preferably, the recess is provided only in one of the first and the second surfaces.
According to such an arrangement, as compared with the above case in which the recess is provided in each of the first and the second surface, the number of the recesses can be smaller. This can facilitate an operation for forming the recesses.
Preferably, the separating means further includes a light shielding member covering the first surface of the first support.
According to such an arrangement, the light shielding member also offers the effect of preventing the optical cross talk between the first lenses. Further, this arrangement prevents light unnecessary for the image formation from entering the first lens array via the first surface. Therefore, it becomes possible to form a clearer image.
Preferably, the separating means further includes a light shielding member covering the second surface of the first support.
According to such an arrangement, it becomes possible t
Fujimoto Hisayoshi
Imamura Norihiro
Takakura Toshihiko
Bednarek Michael D.
Epps Georgia
Harrington Alicia M.
Rohm & Co., Ltd.
Shaw Pittman LLP
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