ETC ILX538K

2-Line Color CCD Linear Sensor
with a 1-Line Spacing
ILX538K
Along with the current rapid growth in the personal computer
market, the color image scanner is poised for rapid growth.
Although Sony has already developed a line of products for
color image scanners, we have now developed a new product
to support A4-size documents at a deusity of 600 DPI : the
ILX538K 2-line color linear sensor with a 1-line spacing.
2-Line Color Linear Sensor
Consisting of an R and B
Dot-sequential Line and a
G Line
Figure 1 shows the block diagram for a
3-line sensor and figure 2 shows the
block diagram of the ILX538K sensor
block. In 3-line sensors, the pixel lines
are usually separated by a spacing of
several pixel widths. Application
systems normally compensate for this
by providing external memory and
performing interline interpolation as
synchronization processing. The
ILX538K consists of 2 lines, a dotsequential R and B line and a G line and
succeeds in reducing the interline spacing to just 1 line.
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2-line color linear sensor consisting of an
R and B dot-sequential line and a G line
Pixel line spacing of 1 line
Analog memory included in the CCD
block.
Pixel size corresponding to a 7-µm pitch
Ultra-low lag
Excellent linearity
Built-in clamp circuit
Built-in sample-and-hold circuit
Analog Memory for Line
Synchronization Provided
in the CCD Block
The ILX538K includes one line of
analog memory for each of the R/B and
G sensor lines and the CCD registers. It
is possible to perform line data
synchronization for the 2-sensor lines
using this memory. This makes
external correction (line data synchronization) memory unnecessary, and can
significantly simplify the peripheral
circuits. Since this analog memory is
provided for both the R/B and G lines,
line data synchronization can be performed for scanning in either direction,
thus provide a high degree of freedom
in end product design.
Pixel Size Corresponding
to a 7-µm Pitch
V
O
I
C
E
Of the 600 DPI color linear sensors
developed to date, the ILX538K
best provides the three critical
sensor aspects; namely a small
pixel size, ease of use, and a narrow line spacing. I’m sure that this
device will be well received in the
color image scanner market as the
indispensable key device for driving further expansion of that market. Once you have been introduced to this product, you will find
it truly indispensable.
Figure 3 shows the block diagram of the
ILX538K. One of the sensor lines is an
R/B dot-sequential lines and the other
is the G line. This structure allows the
ILX538K to achieve a minimum line
spacing of 1 line (7 µm), which is equal
to the pixel spacing. Table 1 presents
an overview of the characteristics of the
ILX538K. The effective pixel size is
5×6 µm (for a 7 µm pitch), and the
ILX538K achieves the high pixel counts
of 2670 effective pixels for the R and B
lines and 5340 for the G line.
Excellent Linearity
Table 2 lists the electro-optical characteristics of the ILX538K. Since the
sensor block signal charges are fully
read out, there is no lag. Also, the
ILX538K provides excellent linearity
from small signals through the saturation output voltage.
Built-in Clamp and
Sample-and-Hold Circuits
The ILX538K includes both clamp and
sample-and-hold circuits for all signal
outputs. Also, the ILX538K provides
two independent parallel sample-andhold circuits for the R/B dot-sequential
output circuits, so that the R and B signals can be output separately to
individual output pins.
Readout gates
D
D
D
D
7 µm
1 line (7 µm)
Line spacing
Readout gates
Resolution
8 lines
600 DPI (A4)
Power supply
Single 10-V power supply
Package
D
D
B
D
5µm × 6µm
Pixel pitch
CCD analog shift register
D
ILX538K
2670 pixels × 2 (R/B), 5340 pixels (G)
Effective pixel size
8 lines
CCD analog shift register
G
Item
Number of effective pixels
D
D
R
D
D
■ Table 1 ILX538K Overview
22pin Cer-DIP
Readout gates
CCD analog shift register
■ Figure 1 Block Diagram of the Sensor Block in a 3-Line Sensor
■ Table 2 Electro-Optical Characteristics
Item
Typical value
R
CCD analog shift register
Sensitivity
D
D
D
B2670
1 line
D
D
G5340
R2670
G5339
---
D
G1
G2
D
D
R1
B1
1-line delay analog memory
Readout gates
Readout gates
1-line delay analog memory
CCD analog shift register
G
2
B
1.2
1.5
V
Image lag
%
Total transfer efficiency
0.02
98
Current consumption
20
mA
Maximum operating frequency
2
MHz
ø2
8
Clamp circuit
VOUT-G 18
øS/H-B
øS/H-G
øS/H-R
22 21 3
Driver
■ Figure 3 ILX538K Block Diagram
9
GND
20
GND
Driver
13 øROG
11 øV1
D
CCD analog shift register
1
2
øCLP øRS
12 øV2
Driver
Clamp pulse & voltage generator
Driver
Driver
D
B2670
R2670
D
D
G5340
G5339
D
R1
B1
Readout gates
1-line delay analog memory
Clamp circuit
Sample-andhold circuit
VOUT-B 5
D
Sample-andhold circuit
D
CCD analog shift register
1-line delay analog memory
Readout gates
D
G1
G2
Sample-andhold circuit
VGG bias circuit
---
%
5
Saturation output voltage
VDD
17
VOUT-R 6
V/(lx·s)
Sensitivity nonuniformity
■ Figure 2 Block Diagram of ILX538K Sensor Block
VGG 4
Unit
1.1
10
GND
14
ø1
%