Apparatus and method for locating an optical module of an...

Facsimile and static presentation processing – Facsimile – Facsimile measuring – testing – or calibrating

Reexamination Certificate

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C358S406000, C358S486000, C358S474000, C382S317000

Reexamination Certificate

active

06529292

ABSTRACT:

BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates in general to an adjusting apparatus and a locating method. More particularly, it relates to an adjusting apparatus and a locating method for locating a lens set and image-receiving device in a optical module of an image-scanning system.
2. Description of the Related Art
FIG. 1
shows an image-scanning system, which comprises a light-radiating device
14
, a image-receiving device
12
, and a lens set
16
. The image-receiving device
12
and the lens set
16
constitute an optical module of the image-scanning system. The light-radiating device
14
may be a cold-cathode tube having a straight line tube. For instance, the image-receiving device
12
may be a charge-coupled device (CCD).
The light-radiating device
14
moves with respect to an object
10
which is, for example, a piece of paper or a picture, along a scanning path as indicated by arrow A. The object
10
reflects the light emitted by the light-radiating device
14
, as indicated by arrows B. The lens set
16
then focuses an image of the reflected light onto the image-receiving device
12
as indicated by arrow C. The image-receiving device
12
transforms the image of the reflected light (the image of the object
10
) into electrical signal for further processing.
The location of the lens set
16
and the image receiving device
12
is essential to the proper functioning of the optical module. First, if the position of the lens set
16
or the image-receiving device
12
has any deviation with respect to the object
10
, then the scanned image will suffer in quality. Second, if the image-receiving device
12
is not located at the required position, then the lens set
16
can not properly focus the image of the reflected light onto the image-receiving device
12
, which therefore cannot receive the scanned image. Furthermore, the lens set
16
must be located at the position where the lens set
16
provides best resolution and appropriate magnification to focus the image of the reflected light onto the image-receiving device
12
; if not, the image received by the image-receiving device
12
will be vague or even distorted due to the variation of the light intensity. Consequently, an adjust apparatus is always used for locating the lens set and the image-receiving device in an optical module of an image-scanning system, thereby eliminating problems such as horizontal deviation of image, received image over the boundary of the image-receiving device, and inadequate magnification and resolution for the image.
FIG. 2
illustrates an adjusting apparatus used in conventional arts. In
FIG. 2
, the adjusting apparatus
20
comprises three patterns
25
,
27
, and
21
provided in parallel and horizontally. Patterns
25
and
27
are used to calibrate the horizontal location of the image-receiving device. Two blank regions
29
are provided at two sides of the pattern
27
, and used to calibrate the boundary location of the image-receiving device. The pattern
21
is used to calibrate resolution; it comprises a plurality of vertical segments
23
disposed in parallel for analyzing resolution. The adjusting apparatus
23
serves as an scanned object when carrying out location process of the lens set and the image-receiving device. The location process includes calibrating the boundary, horizontal position, and the resolution of the image-receiving device and the lens set. In practice, the adjusting apparatus must be moved corresponding to the different location procedures. For example, the adjusting apparatus is moved to a first position such that the scanning line aims at the pattern
27
when locating the boundary of the image-receiving device; and the adjusting apparatus is moved to a second position such that the scanning line aims at the pattern
21
when analyzing the resolution of the image-receiving device and the lens set. Every procedure for locating different item requires additional movement of the adjusting apparatus, therefore increasing the possibility of deviated results due to frequent movement of the adjusting apparatus. Furthermore, the conventional locating process takes a lot of time to calibrate the corresponding positions among the lens set, the image-receiving device, and the adjusting apparatus, thus increasing the time cost.
In addition, analog-to-digital converters are generally used to compensate the light saturation for different illuminations at the image-receiving device when fabricating the image-scanning system (for example a scanner). However, the illumination at the center of the image-receiving device is brighter than that at the edge of the image-receiving device, and the illumination difference will cause the scanned image at the image-receiving device to suffer from color deviation, because the linear region of the analog-to-digital converters have their limits for the compensating process. In addition, the adjusting apparatus depicted in
FIG. 2
can not provide the data to analyze the ratio of the illumination at the center of the image-receiving device to that at the edge of the image-receiving device.
SUMMARY OF THE INVENTION
Therefore, a first object of the present invention is to provide a adjusting apparatus for locating the optical module (a lens set and an image-receiving device), and analyzing the illumination of the scanned image present at the center and two sides of the image-receiving device.
The second object of the present invention is to provide a locating method operating in conjunction with the adjusting apparatus which indicates the adjusting results by showing waveforms on an oscilloscope, thereby improving the accuracy and speed of location process.
To achieve the first object, the adjusting apparatus for locating a lens set and an image-receiving device provided in an optical module of an image-scanning system and analyzing illumination comprises at least the following units:
A first adjusting pattern provided at the center of the adjusting apparatus comprising at least: a white block region provided at the center of the first adjusting pattern for locating the central position of the optical module; and resolution regions provided at both sides of the white block region, for analyzing the resolution of the lens set.
Second adjusting patterns provided at both ends of the first adjusting pattern, for adjusting the boundary and horizontal location of the image-receiving device in the optical module.
Each of the second adjusting patterns comprises at least: two horizontal-deviation adjusting pattern; wherein each of the horizontal-deviation adjusting patterns comprises a first pattern for adjusting the horizontal position and deviation of the image-receiving device when disposed in the optical module, and a second pattern spaced apart from the first pattern; a boundary adjusting pattern for locating the boundary of the image-receiving device when disposed in the optical module, wherein the boundary adjusting pattern comprises the region between the first and second patterns.
The white block region is used in conjunction with the boundary adjusting patterns for detecting the illuminations projected at the center and two sides of the image-receiving device for analyzing the illumination difference between the center and two sides of the image-receiving device.
To achieve the second object, the method for locating the image-receiving device and the lens set and analyzing resolution comprises the following steps:
Provide the lens set between the adjusting apparatus and the image-receiving device such that the adjusting apparatus, the lens set, and the image-receiving device are coarsely aligned along a first direction.
Move the position of the image-receiving device, along a second direction perpendicular to the first direction, until the scanned image projected from the adjusting apparatus can be received by the image-receiving device.
Move the lens set along the first direction for coarsely adjusting the position of the lens set, until a third waveform responsive to the illuminat

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