Registers – Coded record sensors – Particular sensor structure
Reexamination Certificate
2003-02-06
2004-09-28
Le, Thien M. (Department: 2876)
Registers
Coded record sensors
Particular sensor structure
Reexamination Certificate
active
06796502
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates to an image reading apparatus for reading image information of an original such as a photographic film and an illumination apparatus used in the image reading apparatus.
BACKGROUND OF THE INVENTION
When dirt such as dust exists on a transparent original or the surface of a photographic film is damaged (scratched), a conventional image reading apparatus for reading image information of the transparent original such as the photographic film reads even the dirt or scratch, so the image degrades owing to the dirt or scratch. In order to solve this problem, an image reading apparatus for correcting image information obtained by a visible light source by using dust/scratch information obtained by image information obtained by an infrared light source has been proposed (Japanese Patent Laid-Open No. 2001-298593). In this image reading apparatus, the visible light source serving as a surface light source such as a fluorescent lamp and the infrared point light source such as an infrared LED chip are arranged on the side surface of a light guide plate.
In the arrangement of the conventional image reading apparatus described above, however, even if light emitted by the visible light source is uniformly guided to an effective light-emitting surface region by a light guide member upon emitting light beams from the respective light sources, light emitted by the infrared light source cannot sufficiently diffuse since the infrared light source is too close to the effective light-emitting region. Hence, the original is nonuniformly irradiated, and the dust/scratch information cannot be accurately obtained.
Recently, along with the development of a communication network and the increases in speed of a computer and capacity of a storage medium, the color image information is required to be processed at a higher resolution. In particular, when color image information is read by a scanner and the like, a demand has arisen for reading the image more accurately at a higher speed and higher resolution.
When reading the image of the photographic film, a demand has arisen for reading the image information of the photographic film having a plurality of frames in a sleeve form more accurately at a higher speed and higher resolution. As a means for reading a film at a higher resolution, an image reading apparatus which has a means for removing the dust or scratch on the film is proposed. The above Japanese Patent Laid-Open No. 2001-298593 is an example of the image reading apparatus. According to this proposal, the light source including the infrared LED for detecting the dust/scratch information and the light source for reading the image information is arranged as a surface light source, so that the image in which the influence of the dust or scratch is reduced can be read.
The form of the image reading apparatus having the function of removing the dust or scratch on the film will be briefly described with reference to
FIGS. 15
,
16
, and
17
.
FIG. 15
is a schematic sectional view showing an example of an image input apparatus which can read both a reflecting original such as a document original and the transparent original such as the photographic film.
FIG. 16
is a view showing an example of a transparent original light source unit used in the image input apparatus which has the function of removing the dust or scratch as described above.
A transparent original illumination apparatus
500
which is required for reading the transparent original such as the photographic film is arranged in an image reading apparatus
400
, and electrically connected to the image reading apparatus
400
via a transparent original light source lighting inverter
507
and I/F cable
515
so as to be controllable from an image reading apparatus control board
503
. The transparent original illumination apparatus
500
has a transparent original illumination unit
504
for reading the transparent original.
An optical unit
514
includes a first reflecting mirror
509
, second reflecting mirror
510
, third reflecting mirror
511
, and lens
512
which are required for optically forming the image of the transparent original on a CCD image sensor
513
, and a reflecting original illumination light source
508
for irradiating the reflecting original such as the document original, and reads the image while scanning the original in directions indicated by a double-headed arrow shown in
FIG. 15
(in a subscanning direction) by the image input apparatus control board
503
and a motor
516
.
The CCD image sensor
513
and image input apparatus control board
503
are electrically connected to each other via a signal cable
517
. Hence, an electrical signal photoelectrically converted by the CCD image sensor
513
can be obtained as image data by scanning the original while synchronizing the transparent original illumination unit
504
and optical unit
514
by the motor
516
.
A transparent plate
519
which exists between the transparent original illumination unit
504
and a film guide
505
on a document glass table
506
uses transparent glass or a diffusion member. As shown in
FIG. 16
, cold cathode fluorescent lamps (to be referred to as CCFLs hereinafter)
528
and infrared LED arrays
529
for reading the image information on the film original are arranged on the respective end faces in the transparent original illumination unit
504
. Note that a reflecting sheet
532
and diffusion sheet
530
are effective to obtain the uniformities of light-emitting surfaces irradiated with respective light sources.
FIG. 17
is an enlarged view of a portion A in
FIG. 16
, and a schematic view of the light guide member pattern which is used to satisfy the uniformities of surface light sources when the CCFLs
528
and infrared LED arrays
529
are ON.
FIG. 18
is a view showing that the incident light emitted by each CCFL
528
is reflected by the reflecting sheet
532
, and diffused by a light guide member
531
having triangular grooves to illuminate the original. The taper angle or pitch of each triangular groove in the light guide member
531
is adjusted to obtain a diffusion effect, thereby obtaining the effect of the uniform surface light source. The influence of the dust or scratch can be removed, and a high-quality image can be read by scanning the original while line-sequentially or surface-sequentially switching the CCFLs
528
and infrared LED arrays
529
.
In the arrangement of the triangular grooves such as the conventional transparent original light source unit
504
as described above, the uniformity can be obtained by the diffusion effect. However, there is room for improvement about high luminance and high power.
SUMMARY OF THE INVENTION
The present invention has been made in consideration of the above problem, and has as its object to provide a high-quality read image from which dust or scratches are removed in an image reading apparatus with a surface light source.
In order to solve the above problem, and achieve the object, according to the first aspect of the present invention, an illumination apparatus comprises a first light source which emits light in a visible range, a second light source which emits light in an invisible range, and a light guide plate which two-dimensionally guides for illumination light beams emitted by the first and second light sources, wherein a distance between an effective light-emitting region of the light guide plate and an arrangement portion of the first light source is different from a distance between the effective light-emitting region and an arrangement portion of the second light source.
According to the second aspect of the present invention, the illumination apparatus comprises a first light source which emits light in a visible range, a second light source which emits light in an invisible range, and a light guide plate which two-dimensionally guides for illumination light beams emitted by the first and second light sources, wherein a first reflecting surface which reflects irradiation light from the second light s
Hanabusa Mitsugu
Nogami Ryuji
Labaze Edwyn
Le Thien M.
Morgan & Finnegan L.L.P.
LandOfFree
Illumination apparatus and image reading apparatus does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Illumination apparatus and image reading apparatus, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Illumination apparatus and image reading apparatus will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-3246564