AMIS-710310-DR

AMIS-710310-DR: 300dpi Two-Level Digital Output Module Data Sheet 1.0 General Description The AMIS-710310-DR (PI310MC-DR) is a contact image sensor (CIS) module with an additional on-board circuit that digitizes the analog pixels from the CIS image sensor to a “background-tracking”, two-level digital output signal. The module uses MOS image sensor technology to gain high-speed performance and high sensitivity. The AMIS-710310-DR is suitable for scanning documents with widths of 89mm and with resolutions of 11.8 dots per millimeter (dpm). It has broad applications but is specifically designed for the following areas: • Where data compression is required, such as in data transmissions. • Where component pin-out count must be kept to a minimum. The background-tracking-digitizing circuits in the AMIS-710310-DR have been referred to as the “dynamic threshold” two-level A/D converter. For the purpose of describing the module’s characteristics, this “dynamic threshold” processing circuit shall herein be referred to as the “tracking digitizer”. 2.0 Key Features • • • • • • • Light source, lens and sensor are integrated into a single module 11.8dpm resolution, 89mm scanning length Up to 423µsec/line scanning speed, with 2.5MHz pixel rate (see Table 3, Note 3) Wide dynamic range two-level tracking digital output (“Dynamic Threshold Digitizer”) Standard Yellow-Green light source (other colors are available) Compact size ≅ 13mm x 25.6mm x 102mm low power Light weight 3.0 Module Description Figure 1: Block Diagram of AMIS-710310-DR AMI Semiconductor – May 06, M-20566-001 www.amis.com 1 AMIS-710310-DR: 300dpi Two-Level Digital Output Module Data Sheet The AMIS-710310-DR module consists of 11 sensors that are cascaded to provide 1056 photo-detectors with their associated multiplex switches and a digital shift register that controls its sequential readout. Mounted in the module is a one-to-one graded-indexed micro lens array that focuses the scanned documents to image onto its sensing plane. A buffer amplifier amplifies the video pixels from the image sensors and passes them to the analog digitizing circuit, where video pixels are converted to digital signal and passed to the output of the module. See Figure 1. Illumination is accomplished by means of an integrated LED light source. All components are housed in a small plastic housing with a cover glass which acts as the focal point for the object being scanned and protects the imaging array, the micro lens assembly, and the LED light source from dust. The pictorial of the AMIS-710310-DR cross section is shown in Figure 2. Figure 2: Inside Pictorial of the Module I/O to the module is an 8-pin flex cable connector (see I/O Connector, under Specifications) located on one end of the module. The connector is on the top of the module with the glass window facing down and it is located on the opposite side of the module (see the Mechanical Housing under Mechanical Structure). AMI Semiconductor – May 06, M-20566-001 www.amis.com 2 AMIS-710310-DR: 300dpi Two-Level Digital Output Module 4.0 Circuit Description and Operation Data Sheet Figure 3 is a simplified block diagram of the analog tracking digitizer. Fundamentally, the tracking digitizer transforms the signal output from an existing CIS module on the market today. It takes the analog signal from the CIS section of AMIS-710310-DR and derives a tracking background reference signal. Then this reference is compared against the output signals from the CIS section. The resulting signal from this comparison produces a two-level digital signal that is high when the pixel signal is brighter than the background and remains at zero as long as the signal is darker than the background signal. Figure 3: Analog Signal Reference Generator and a Single Bit Comparator Figure 1 depicts the two basic circuits, the CIS (image sensors and video amplifier) and the tracking digitizer. In the CIS section, the module has 11 serially concatenated AMIS-7200030 (PI3012A) image sensors, accordingly, the image sensors will span one scanningread line width that is 11 sensor times 96 pixel elements/sensor, or 1056 pixel elements. In operation, the module produces the analog image pixel signals that are proportional to the exposure on the corresponding picture element on the document (the video signal), then passes the signal to the tracking digitizer. In turn, the digitizer processes the analog image pixels to digital image pixels. The analog image pixels, at test point TV, are separated into two signals. One generates the reference signal and the other remains unmodified. These unmodified image pixels are applied to one of the inputs of the comparator. The reference signal is applied to the second input of the comparator. The results of the comparison are the digital image pixels. This digital output is produced in two levels, determined by the difference between the background reference signal and the analog image pixels. A digital pixel output value of “one” represents the analog image pixel that is brighter than the background and digital pixel level value of “zero” represents the image pixel that is darker than background. AMI Semiconductor – May 06, M-20566-001 www.amis.com 3 AMIS-710310-DR: 300dpi Two-Level Digital Output Module 5.0 Specifications 5.1 I/O Connector The pins and their functions are listed in Table 1. Table 1: Pin Configuration Pin Number 1 2 3 4 5 6 7 8 Symbol DIGOUT Vdd (+5V) Vn (-10 to -5V) SP GRD CLOCK GLED VLED Names and Functions Digital video output Ground; 0V Negative power supply SP for the shift register Ground; 0V Clock for the shift register Return for the LED light source Power in for the LED light source Data Sheet The connector is an 8 pin 1mm surface mount flex input, Molex 52207-0890. 5.2 Inputs There are five inputs: • • • • • Clock is on Pin 6 of the I/O connector. This is the main clock input into the CIS module. SP is on Pin 4. This is the start clock input to the CIS module. VDD is on Pin 2. This is a + 5V supply. VN is on Pin 3. This is a -10 to -5V supply. VLED is on Pin 8. This is a +24V supply for the LED light source. Note: The power return for the LED light source is GLED on Pin 7 and the ground return for the CIS modules is Pin 5. 5.3 Video Output DIGOUT is on Pin 1 of the I/O connector. This is the digital video output from the CIS module. Reflection off the dark target produces a digital signal of “0” level, while the white reflection off the white target produces a digital level of “one”. The amplitudes of the white and dark are listed in Table 2. 6.0 Electro-Optical Characteristics at 25°C Table 2: Electro-Optical Characteristics at 25 C Parameter Number of photo detectors Pixel-to-pixel spacing Line scanning rate Clock frequency Bright output Dark output Note: (1) The tint is specified with a 2.0MHz clock frequency. In operation, the time constants in the reference generator are set to match the initial exposure time, hence the time constant will determine the optimum integration time. Note that the integration time is also a function of the clock frequency. Accordingly, it is highly recommended that the parameters be factory adjusted for the specific applications. ° Symbol Tint (1) Parameter 1056 84.7 528 2.0 >3.2