Structure of foldable optical path

Details Structure of foldable optical path Structure of foldable optical path

2002-06-04

2003-02-18

Phan, James (Department: 2872)

Facsimile and static presentation processing

Facsimile

Specific signal processing circuitry

C359S212100, C359S215100, C358S483000

Reexamination Certificate

active

06522428

ABSTRACT:

BACKGROUND OF INVENTION
1. Field of Invention
The present invention relates to a structure of foldable optical path. More particularly, the present invention relates to a structure of foldable optical path inside the scanning module of a charge couple device (CCD) type optical scanner.
2. Description of Related Art
With the progress in multimedia technology, the improvement of processing of image data promoting the development of computer peripheral device such as scanner. From handheld monochrome type to present full color and high-resolution type, the scanner can produce a finer and vividly image. Today, a scanner is a widely used computer peripheral device for capturing document image and converting the document image to digital signals for computer process.
The optical system
100
of the conventional optical scanner as illustrated in
FIG. 1
has a light source
110
, a reflection mirror set
120
, an image-formation set
130
, and an optical sensor such as a charge couple device (CCD)
140
. While performing scanning, light from the light source
110
is incident onto a document
300
putting on a light transmissible plate
200
to obtain an image light
310
by reflection or transmission. The reflection mirror set
120
comprises several reflection mirrors
121
,
122
,
123
and is located in an optical path of the image light
310
. The image of document
300
on the light transmissible plate
200
is directed to the reflection mirror set
120
and reflected to the image-formation set
130
, such as a lens set, by the reflection mirror set
120
. The image-formation set
130
can receive the image light
310
of the document
300
transmitted by the reflection mirror set
120
, focuses and projects the image light
310
onto the charge couple device
140
. The above-mentioned is the optical path of the image light
310
of the document
300
transmitting in the optical system
100
of the optical scanner.
The charge couple device mentioned above transfers the light into photoelectric current by photoelectric transformation and saves the current in a storage electrode to convert into a signal charge, then converts the charge into different potential differences. The optical scanner utilizes these different potential differences to form the different bright and dark level, then displays the image by the gray scale light.
Furthermore, CCD is one kind of semi-conductor IC devices and manufactured by semi-conductor process. CCD's resolution won't be affected by the manufacture easily. However, the length of the CCD is much shorter than the width of normal documents or pictures, it needs to utilize a image-formation set to reduce the scale of the image when scanning, in order to scan the full image. Thus the size of the system will be larger, and it wastes time of fabricating and adjusting.
Contact image sensor (CIS) is another type of linear scanner commonly used for scanning an image or a document. The image or document is captured in an electronic format for ease of storage, display, processing and transmission. Due to a modular design, the CIS is easy to assemble, light, compact and costs less to produce.
FIG. 2
a
is a front view of the scanning module of a conventional contact image sensor and
FIG. 2
b
is a cross-sectional view of the scanning module. As shown in
FIGS. 1
a
and
1
b,
a conventional contact image sensor (CIS)
400
consists of a linear light source
404
, a self-focus lens array
401
and a sensing array
402
over a substrate board
403
. The light source
404
, the self-focus lens array
401
, the sensing array
402
and the substrate board
403
are mounted on an aluminum frame
405
. In a scanning operation, the self-focus lens array
401
reflects light coming from the original document
300
and forms an image on the sensing array
402
. The sensing array
402
converts the color or the gray step level of a line of the document
300
into electronic signals. Throughout the scanning session, the scanning surface of the scanning module
400
in constant contacts with a document platform
210
, and the document
300
is pulled forward or backward by a roller
500
for scanning.
The self-focus lens array
401
is constructed of a row of small-caliber radial gradient index lens, wherein the refractive index of each lens varies along the radial direction gradually, thus the lens are able to format a image. The whole lens array can format the image of one line of the original document on the sensing array in a ratio of 1:1. Compared with CCD which uses a normal image-formation set to format a image, the advantages of CIS which uses the self-focus lens array to format the image are the shorter optical path and the thinner and lighter applied system. However, the disadvantages of CIS are the depth of field is short, and the mechanical design and the control of the system need to be more precise than CCD.
As a conclusion, the advantages of the optical scanner which uses CIS are small-size and able to be portable, but its disadvantage is the depth of field is short, thus it's difficult to get a clear image when scanning a uneven document or picture. The advantages of the optical scanner which uses CCD is the longer depth of field, but its disadvantage is the mechanical design of the system can't be compact, thus it's not convenient to carry it. Moreover, since the document must be put on the light transmissible plate of the CCD type optical scanner while scanning, so it's not convenient in operation when scanning a thick book or large-size newspapers or magazines. Although some small-size flatbed scanners are able to put on a book or large-size newspapers or magazines to scan downward, but a user ought to hold the whole scanner during the scanning operation. Even the scanning result of the early-phase hand-held scanner is easy to be affected by operation cause it needs a user to push the scanner by hand to proceed the scanning operation.
SUMMARY OF INVENTION
Accordingly, one object of the present invention is to provide a structure of foldable optical path that can be use in the optical scanners of a CCD type or a type of non-contact imaging sensor. The structure of foldable optical path arranges part of the optical path in a foldable packing device, thus the scanner is able to utilize normal lens with better depth of field and makes the scanner more compact for the convenience of operation and carrying. A user doesn't have to push the scanner to proceed the scan operation. After the foldable packing device is folded, it's able to save the cost of package and storage because the volume of the scanner is decreased.
To achieve these and other advantages and in accordance with the purpose of the invention, as embodied and broadly described herein, the invention provides a structure of foldable optical path for an optical scanner. The optical scanner at least having a main frame, a light transmissible plate, a light source, a reflection mirror set, an image-formation set, and an optical sensor. The light source illuminates a document to get an image light. The reflection mirror set is arranged in an optical path of the image light to direct the image light to the optical sensor. The image-formation set is arranged in the optical path between the reflection mirror set and the optical sensor. The document contacts with the light transmissible plate during scanning. The structure of foldable optical path comprises as follows.
A foldable packing device is coupled to the main frame by a rotation pivot axis. The foldable packing device is able to rotate from a first position, at which the scanner is under a scanning operation, to a second position, at which the foldable packing device is folded via a pivot axis. Wherein the image-formation set and the optical sensor are disposed in the interior of the foldable packing device. While the foldable packing device is at the first position, the optical path of the image light will be directed into the interior of the foldable packing device through the image-formation set to th

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