Radiant energy – Photocells; circuits and apparatus – Photocell controlled circuit
Reexamination Certificate
2001-07-11
2002-01-08
Allen, Stephone B. (Department: 2878)
Radiant energy
Photocells; circuits and apparatus
Photocell controlled circuit
C358S475000, C358S482000
Reexamination Certificate
active
06337476
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to an image reading apparatus such as a scanner or a facsimile apparatus.
2. Related Background Art
As shown in the sectional view of FIG.
1
and the plan view of
FIG. 2
, an image sensor used in an original reading apparatus comprises a sensor IC
1
, a sensor board
2
on which the sensor IC
1
is mounted, a lens array
3
, an illumination unit
4
, a cover glass
5
, and a frame
6
for positioning/holding these members. The illumination unit
4
comprises lead frame type LEDs
7
serving as light sources, a light guide
8
, and a housing
9
for positioning/holding the LEDs
7
and the light guide
8
.
FIGS. 3A and 3B
are sectional and side views, respectively, showing the detailed structure of the illumination unit
4
. Referring to
FIGS. 3A and 3B
, the illumination unit
4
is constituted by the lead frame type LEDs
7
serving as light sources, the columnar light guide
8
consisting of a transparent member of, e.g., an acrylic resin, and the housing
9
which has a hexagonal section to position/hold the LEDs
7
and the light guide
8
.
The LEDs
7
are arranged at the two ends of the light guide
8
such that light beams are incident into the light guide
8
. The light guide
8
has a diffusion surface
10
. Fine tapered portions are continuously formed on the diffusion surface
10
along the longitudinal direction of the light guide
8
, as shown in
FIG. 4. A
light beam incident on this tapered portion at an incident angle &thgr; of 41° or more (when the light guide
8
consists of an acrylic resin and has a refractive index n of 1.5) satisfies the total reflection angle condition so that the light beam emerges in a desired direction.
The housing
9
for positioning/holding the LEDs
7
and the light guide
8
has, on a surface corresponding to one of the six sides of its hexagonal section, a slit
12
for passing light in the exit direction. To ensure a light amount, the light guide
8
preferably has a white-based color with a high light reflection efficiency. The light guide
8
is formed of, e.g., an ABS resin.
The LEDs
7
are electrically connected to an external system through connector cables
16
. Since two LEDs sandwich the light guide
8
, two connector cables
16
are necessary. Cables
16
are used to connect leads
11
of the LEDs
7
to driving unit
18
, which is used to turn the light source on.
In the above prior art, the LEDs
7
are electrically connected to the external system through the connector cables
16
. For this reason, the following problems are posed.
(1) The number of connector cables
16
, equal the number of LEDs
7
. The cost of the connector cables
16
and an increase in labor for attaching the connector cables
16
to leads
11
of the LEDs
7
result in an increase in cost.
(2) Electrical connection between the image sensor and the external system is complex and therefore easily affected by noise.
(3) A predetermined illuminance on the original read line can hardly be obtained because no luminance adjusting circuit for the LEDs
7
can be inserted between the LEDs
7
and the external system. For this reason, a sensor output (“bright” sensor output) in reading, e.g., a white original largely varies between image sensors as end products.
SUMMARY OF THE INVENTION
It is an object of the present invention to enable high-quality image read processing.
It is another object of the present invention to provide an image reading apparatus having a high mechanical strength.
It is still another object of the present invention to achieve cost and size reduction of an image reading apparatus.
It is a further object of the present invention to minimize variations in read outputs.
In order to achieve the above objects, according to an aspect of the present invention, there is provided an image reading apparatus comprising a light source for irradiating a target object, a sensor IC having a photoelectric conversion device for converting light information from the target object irradiated by the light source into an image signal, a sensor board separated from the light source and mounted with the sensor IC, a frame which incorporates the light source, and fixing means for fixing a lead member from the light source to the sensor board and fixing the sensor board to the frame.
With this arrangement, a sufficient mechanical strength can be ensured while achieving size and cost reduction of the apparatus. In addition, variations in read outputs can be suppressed, so that a high-quality image can be read.
Other features, objects and advantages of the present invention will be apparent from the following specification in conjunction with the accompanying drawings.
REFERENCES:
patent: 4996606 (1991-02-01), Kawai et al.
patent: 5019897 (1991-05-01), Shirata et al.
patent: 5270840 (1993-12-01), Ogata et al.
patent: 5331433 (1994-07-01), Sato
patent: 5418384 (1995-05-01), Yamana et al.
patent: 5434682 (1995-07-01), Imamura et al.
patent: 5477329 (1995-12-01), Imamura et al.
patent: 5579114 (1996-11-01), Imamura et al.
patent: 5780840 (1998-07-01), Lee et al.
patent: 5965870 (1999-10-01), Tabata
patent: 5986253 (1999-11-01), Tabata
patent: 6002494 (1999-12-01), Tabata
patent: 6081351 (2000-06-01), Tabata
patent: A-05-130329 (1993-05-01), None
patent: A-06-3527 (1994-01-01), None
patent: A-07-170373 (1995-07-01), None
patent: A-07-193675 (1995-07-01), None
patent: A-08-163320 (1996-06-01), None
LandOfFree
Image reading apparatus having light source electrically and... does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Image reading apparatus having light source electrically and..., we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Image reading apparatus having light source electrically and... will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2837961