IMAGE SENSOR
Flat panel sensor
C7921CA
High resolution and high frame rate
Flat panel sensor C7921CA is a digital X-ray image sensor newly developed as key devices for non-destructive inspection, biomedical imaging,
X-ray microscopy and other real-time X-ray imaging applications requiring high resolution and high image quality. C7921CA consists of a sensor
board and a control board, both assembled in a thin, flat and compact package. The sensor board contains a CsI scintillator plate, a two-
dimensional photodiode array with FET switches and a signal processing IC chip. The photodiode array has a 1056 脳 1056 pixel format with
minimized blooming and is highly sensitive to bluish green light emitted from the CsI scintillator. Each row of pixels is addressed in sequence by
the vertical shift register connected to the gate line.
Light emission occurs when X-rays are absorbed in the CsI scintillator. This light emission enters directly into the two-dimensional photodiode
array where an electric charge is stored in each pixel according to the light intensity. This charge is then transferred to the corresponding data line
by applying a control signal to the vertical shift register.
The sensor board also has 8 charge sensitive amplifier arrays each having 132 channel amplifiers with a horizontal shift register. These amplifiers
with a total of 1056 channels are connected to a CDS (Correlated Double Sampling) circuit that senses the charge on each video line and sends it
as the analog video signal from each amplifier array. The control board converts the analog video signal into a 12-bit digital signal and outputs it to
an external frame grabber from a 12-bit parallel port.
C7921CA delivers a frame rate of 16 frames per second using 4 脳 4 binning and is ideal for high frame rate applications, also ideal for
applications requiring high resolution because of its 50 碌m pixel size. Massive digital image data can easily be monitored on a display unit by
using a frame grabber board and video memory installed in the PC. C7921CA will prove ideal tools for real-time X-ray imaging and processing
where easy-to-use, high-resolution X-ray digital image sensors are needed.
Applications
Features
l
Non-destructive inspection
l
Digital X-ray photography
s
Block diagram
PIXEL NUMBER
1 2
1057
1055 1056
2111 2112
SHIFT REGISTER
l
High quality image: 1056 脳 1056 pixels
l
Pixel size: 50 脳 50 碌m
l
No image distortion
l
Digital output (12 bits)
l
High-speed imaging by binning operation:
16 frames/s (4 脳 4 binning)
l
Wide dynamic range
l
High cost performance
EXTERNAL POWER SUPPLY
A. Vdd, D. Vdd V (鹵7.5)
(not attached)
SCINTILLATOR
(52.8 mm 脳 52.8 mm)
PHOTODIODE
ARRAY
IntExt
IntExt
BINNING
(bin0, bin1)
1115135
AMP ARRAY No. 1
1115136
AMP ARRAY No. 8
TIMING
PULSE
GENERATOR
BIAS
GENERATER
BUFFER
AMP
BUFFER
AMP
PROCESSING
AMP
OSCILLATOR
ExtTrg
Vsync
Hsync
Pclk
A/D
FIFO
VIDEO OUTPUT
(12 BIT DIGITAL)
PROCESSING
AMP
A/D
FIFO
KACCC0170EA
1
1
2
3
4
5
6
7
