Radiant energy – Photocells; circuits and apparatus – Photocell controlled circuit
Reexamination Certificate
2002-03-08
2003-10-28
Pyo, Kevin (Department: 2878)
Radiant energy
Photocells; circuits and apparatus
Photocell controlled circuit
C348S294000, C377S063000
Reexamination Certificate
active
06639202
ABSTRACT:
This application incorporates by reference of Taiwan application Serial No. 90107009, filed Mar. 23, 2001.
BACKGROUND OF THE INVENTION
1. Field of the Invention
The invention relates in general to a multi-resolution charge-coupled device (CCD) sensing apparatus, and more particularly to a multi-resolution charge-coupled device (CCD) sensing apparatus applied to the CCD module and the CIS (Contact Image Sensor) module.
2. Description of the Related Art
In recent years, the scanner has been widely used. The user requires choosing from scanning modes of different resolutions for scanning in accordance with the property of the document to be scanned. Conventionally, there are several ways for setting the resolution, which might be accomplished by using either software or hardware. The way by using hardware is usually direct and fast.
The scanning procedures of the scanner with the CCD module are stated as follows. The carriage in the scanner has an illumination source. After the illumination source produces the light, the light is reflected by the document to be scanned and directed back to the carriage. The light signal is processed by the optical components, such as the mirrors and lenses, and received by the CCD module. The CCD module senses the magnitude of light signal and then generates corresponding scanning image data.
Referring to
FIG. 1
, a CCD module using a conventional charge-coupled device (CCD) sensing device is shown. The CCD module
100
includes a CCD sensing device
102
, a control circuit
104
and an output capacitor C. The CCD sensing device
102
mainly includes a photo sensor set
106
, shift gate
108
, and CCD shift register
110
. The CCD sensing device
102
with a resolution of 1200 dpi (dots per inch) is taken for example. The photo sensor set
106
includes 1200 photo sensing components D
1
~D
1200
for converting the light signals into the charge signals S
1
~S
1200
. The photo sensing components maybe photo diodes. The shift gate
108
is used for controlling the transmission of the charge signals S
1
~S
1200
. When the photo sensing components D
1
~D
1200
are exposed to light for a predetermined period of time, the photo sensing components D
1
~D
1200
generate enough amount of charges, and then the shift gate
108
is open so that the charge signals S
1
~S
1200
are sent to the CCD components E
1
~E
1200
in the CCD shift register
110
. Subsequently, the charge signals S
1
~S
1200
stored in the CCD components E
1
~E
1200
are serially outputted. The control circuit
104
is used for serially storing the charge signals, which are outputted due to the control of the CCD shift register
110
, in the capacitor C to acquire the analog output signal Out. The output signal Out is processed by a next stage circuit (not shown) and the scanning image data are then acquired.
However, using different scanning modes of different resolutions for a user is necessary. For example, the scanning mode of high-resolution for scanning is required if the document to be scanned is a high color image. If the document to be scanned is text, it simply requires the scanning mode of low-resolution for scanning. In
FIG. 1
, the CCD sensing device
102
is a high-resolution sensing device, some properties of the CCD sensing device
102
has to be discarded when it is used for scanning at a low resolution.
As shown in
FIG. 1
, the CCD sensing device
102
with a high resolution is used for scanning at a low resolution of 600 dpi and the operation is described as follows: after the photo sensing components D
1
~D
1200
are exposed to light, the charge signals S
1
~S
1200
are stored in the CCD components E
1
~E
1200
. When the charge signals S
1
~S
1200
are outputted, the control circuit
104
will store 600 charge signals, such as S
2
, S
4
, S
6
. . . S
1200
, in the capacitor C in order to acquire the scanning image data of 600 dpi. Although the scanning image data are of low resolution, the time for shifting out the electric charges stored in the CCD components to the capacitor C is still the same as before and does not decrease any. Therefore, for the conventional CCD sensing device
102
, scanning at a low resolution does not enhance the scanning speed and takes the same time with scanning at a high resolution.
The chips for the CCD sensing device with different resolutions have been widely used in the marketplace. To solve the above-mentioned problem, the CCD module having multiple CCD sensing devices with several different resolutions becomes available in the market.
Referring to
FIG. 2
, the conventional CCD module having multiple CCD sensing devices is shown. The CCD module
200
having three CCD sensing devices is an example for further illustration. The CCD module
200
has a CCD sensing device
202
a
with a resolution of 1200 dpi, a CCD sensing device
202
b
with a resolution of 600 dpi, and a CCD sensing device
202
c
with a resolution of 300 dpi. The CCD sensing devices
202
a,
202
b,
and
202
c
have 1200 photo sensing components Da
1
~Da
1200
, 600 photo sensing components Db
1
~Db
600
, and 300 photo sensing components Dc
1
~Dc
300
respectively. The CCD shift registers
210
a,
210
b,
and
210
c
in the CCD sensing devices
202
a,
202
b,
and
202
c
are respectively controlled by the pulse signals CK
1
, CK
2
, and CK
3
and have 1200 CCD components Ea
1
~Ea
1200
, 600 CCD components Eb
1
~Eb
600
, and 300 CCD components Ec
1
~Ec
300
respectively. The shift gates
208
a,
208
b,
and
208
c
respectively control the transmission of the charge signals of the CCD sensing devices
202
a,
202
b,
and
202
c.
When the user chooses different scanning modes of different resolutions for scanning, the control circuit
204
will choose the outputs of the corresponding CCD sensing devices
202
a,
202
b,
and
202
c
and send them to the capacitor C. That is to say, while scanning, the photo sensor sets
206
a,
206
b,
and
206
c
are simultaneously exposed to light and store the charge signals in the CCD shift registers
210
a,
210
b,
and
210
c.
When choosing the scanning mode of 1200 dpi, the control circuit
204
chooses the output of the CCD shift registers
210
b
or
210
c.
Since the CCD components of the CCD shift registers
210
b
and
210
c
are both far less than that of CCD shift registers
210
a,
the time to shift out the stored charges is far less in the CCD components Eb
1
~Eb
600
or Ec
1
~Ec
300
than in the CCD components Ea
1
~Ea
1200
. Therefore, using the CCD module in
FIG. 2
while scanning at a low resolution will enhance the scanning speed.
Even so, using the CCD module
200
in
FIG. 2
will confront the following disadvantageous situations. The conventional CCD module
200
uses the chip consisting of three juxtaposed CCD sensing devices with different resolutions. Failure to precisely focus might be caused during exposure to light. The photo sensor sets
206
a,
206
b,
and
206
c
are parallel with one another and simultaneously receive the exposures of the light signals from the same optical components. If the optical components are set to focus on the photo sensor set
206
a,
scanning at a low resolution might cause failure to precisely focus and the scanning quality might be seriously influenced. Besides, it is necessary to use three different CCD sensing devices belonging to three chips. The required size is very large and the cost is quite high.
SUMMARY OF THE INVENTION
It is therefore an object of the invention to provide a multi-resolution charge-coupled device (CCD) sensing apparatus, used for scanning at different resolutions. The multi-resolution CCD sensing apparatus along with a photo sensor set and several CCD shift registers achieve the economy in size, low cost, and high yield rate. It speeds the scanning at a low resolution without causing failure to focus and therefore enhances the image scanning quality.
The invention achieves the above-identified objects by providing a multi-resolution charge-coupled device (CCD) sensing apparatus, comprising a photo sensor set, a shift gate, and at least one fi
Avision Inc.
Pyo Kevin
Rabin & Berdo P.C.
Sohn Seung C.
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