™ Peripheral Imaging Corporation PI214MC-DR 200DPI CIS Two Level Digital Output Module Engineering Data Sheet Key Features • Light source, lens, and sensor are integrated into a single module • 8 dpm resolution, 216 mm scanning length • Up to 440 µsec/line scanning speed, with 4.0 MHz pixel rate (See Table 3, Note 2.) • Wide dynamic range • Two-Level Tracking Digital Output (“Dynamic Threshold Digitizer”) • Red (660 nm) light source (Other colors are available) • Compact size ≅ 19.5 mm x 21.5 mm x 232 mm • Low power • Light weight General Description The PI214MC-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 “backgroundtracking”, two-level digital output signal. It is based on Peripheral Imaging Corp’s CIS module that employs MOS image sensor technology to gain its high-speed performance and high sensitivity. The PI214MC-DR is suitable for scanning documents with width of 216 mm and with resolution of 8 dots per millimeter. Its has a broad applications, but specially designed for the following areas: Page 1 of 8 PI214MC-DR, 11/29/99 • • 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 PI214MC-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”. Module Description GLED LED LED LED LED LED LED LED LED VLED ROD LENS 1726 PHOTO SENSORS 1 2 3 4 5 1727 1728 ---------------- VIDEO LINE VN(-V) VDD (+5) SHIFT REGISTER GRD BUFFER VIDEO AMP CP SP TRACKING DIGITIZER DIGOUT GRD Figure 1. PI214MC-DR Module Block Diagram. The PI214MC-DR module consists of 27 sensors that are cascaded to provide 1728 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 analog digitizing circuit, where video pixels are converted to digital signal and passed to output of the module. See Figure 1, the block diagram of the PI214MC-DR module. Illumination is by means of an integrated LED light source. All components are housed in a small plastic housing which has a cover glass which acts as the focal point for the object being scanned and protects the imaging array, micro lens assembly, and LED light source from dust. The pictorial of PI214MC-DR cross section is shown, below, in Figure 2. Page 2 of 8 PI214MC-DR, 11/29/99 DOCUMENT SURFACE GLASS WINDOW ROD LENS MODULE HOUSE LIGHT PATH D LE R BA SENSORS PCB INSIDE PICTORIAL OF MODULE FIGURE 2. I/O to the module is a 2 X 2 mm 16-pin Unshrouded Connector (See I/O pin assignment, under Specifications) located on one end of the module (see module drawing). Circuit Description and Operation See Figure 3, a simplified block diagram of the analog tracking digitizer. Fundamentally, the tracking digitizer transforms the signal output from a CIS module existing on the TWO LEVEL IMAGE PIXELS FROM THE CIS COMPARATOR DIGITAL OUTPUT REFERENCE LEVEL GENERATOR ANALOG SIGNAL REFERENCE GENERATOR AND A SINGLE BIT COMPARATOR FIGURE 3. market today. It takes the analog signal from the CIS section of PI214MC-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 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. Page 3 of 8 PI214MC-DR, 11/29/99 Figure 1, PI214MC-DR block diagram depicts the two basic circuits, the CIS (image sensors and video amplifier) and the tracking digitizer. In the CIS section, the module has 27 serially concatenated PI3004B image sensors, accordingly, the image sensors will span one scanning-read line width that is 27 sensor times 64 pixel elements/sensor, or 1728 pixel elements. In operation the module produces the analog image pixel signals that are proportional to 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 input 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 of value “one” represents the analog image pixel that is brighter than the background and digital pixel level of value “zero” represents the image pixel that is darker than background. Specifications I/O Connector The table of pins and their functions are listed in Table I, Pin Configuration. Pin Number 1,2,4&8 3 5&6 7 9&10 11&12 13&14 15&16 Symbol GRD DIGOUT VDD SP Vn Clock (CP) GLED VLED Names and Functions Ground; 0 V Digital Video Output Positive Power Supply Start Pulse for the shift register Negative Power Supply Clock for the shift register Return for the LED light source Power in for the LED light source. Table 1. Pin Configuration Inputs: There are five inputs: • Clock (CP): This is the input for the main sampling clock. • SP: This is the start pulse input for initiating the scan. • VDD: This is an input for the + 5 Volts positive supply. Page 4 of 8 PI214MC-DR, 11/29/99 • VN : This is the input for the -5 Volts negative supply. • VLED: This is the input for the +5 Volts power supply for the LED light source. Note: Power return for the LED light source is GLED on Pin 13 &14, where as the rest of ground returns are on Pins 1,2,4 & 8. Video Output: DIGOUT on pin 3 of the I/O connector is the only output I/O. Pin 3 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 the table below: Electro-Optical Characteristics (25° C) Table 2. Electro-optical characteristics at 25° C. Parameter Symbol Number of photo detectors Pixel to pixel spacing Line scanning rate Tint (1) Parameter 1728 125 440 Units elements µm µsec Clock frequency Bright output Dark output 4.0 >3.2 <0.8 MHz Volts Volts f Digital Video Output Signal Note @ 4.0 MHz clock frequency (1) The Tint is specified with a 4.0 MHz clock frequency. In operation the time constants in the reference generator is set to match the initial exposure time, hence of the generator’s time constant will determine the optimum integration time. Note, the integration time is also a function of the clock frequency. Accordingly it is highly recommended that the parameters be factory adjust for the specific applications. Table 3. Recommended Operating Conditions (25 °C) Item Power Supply Input voltage at digital high Input voltage at digital low Clock frequency Symbol Vdd Vn. VLED Idd Ivn ILED Vih Vil f Min Vdd-1.0 0 Mean 5.0 -5.0 5.0 35 20 450 Vdd-.5 Page 5 of 8 PI214MC-DR, 11/29/99 Max 500 Vdd 0.8 4.0 Units V V V mA mA mA V V MHz Clock pulse high duty cycle Clock pulse high duration Integration time Operating temperature Clock Tint Top 25 62.5 (1) 0.440(2) 25 50 % ns ms 0 C Note: (1) Clock pulse high is specified at 4.0 MHz at 25% duty. (2) The Tint is specified with a 4.0 MHz clock frequency. In operation the time constants in the reference generator is set to match the initial exposure time, hence the time constant of the reference generator will determine the optimum integration time. Accordingly it is highly recommended that the parameters be factory adjust for the specific applications Switching Characteristics (25°C) The switching characteristics for the I/O clocks are shown in Figure 4, Module Timing Diagram. The timing parametric values and their symbols are given in the Table 4. to CP tprh tdh tdh SP tds tdl Vanalog tsh tddl tdodl Digout MODULE TIMING DIAGRAM FIGURE 4. Table 4. Switching Parameter and Timing Symbol Definition Clock cycle time Clock pulse width Clock duty cycle Prohibit crossing time Symbol to tw tprh Min. 250 62.5 25 15 Typical Page 6 of 8 PI214MC-DR, 11/29/99 Max. 50 Units ns ns % ns of Start Pulse Data setup time Data hold time Signal delay time Signal settling time Digital Signal Delay Digital Signal Off Delay tds tdh tdl tsh tddl tdodl 20 20 50 120 ns ns ns ns ns ns 50 20 Table 5 Absolute Maximum Rating: Parameter Symbols Power supply voltage Input clock pulse (high level) Input clock pulse (low level) Units Vdd Idd Vn Ivn VLED ILED Vih Vil Maximum Rating 10 375 -10 30 5.5 500 Vdd – 0.5 -0.8 Top Hop Tstg Hstg 0 to 50 10 to 85 -25 to+75 5 to 95 0 V mA V mA V mA V V Table 6 Operating Environment Operating temperature Operating humidity Storage temperature Storage humidity Page 7 of 8 PI214MC-DR, 11/29/99 C % 0 C % Module Mechanical Structure N AN IO SC CT RE DI .5 82 2 23 .5 82 1 PIN 6.0 AD RE E LIN m 2m 8 ctor x 2 nne co Ø 1.65 +/- ALL DIMENSIONS ARE IN mm UNLESS OTHERWISE SPECIFIED. HOLE 21.5 SIDE TAPE 1x1 - M2 TAP SIZE USE (DP8) 11.5 +/-0.2 19.5 +/-0.2 Ø 2.2 +/-0.05 HOLE 2x2 - M2.6 TAP SIZE (DP6) 6.8 +/-0.2 15.5 +/-0.2 16.2 +/-0.2 THE SURFACE OF THE GLASS 1.25 END VIEW FIGURE 6. MECHANICAL STRUCTURE ©1999 Peripheral Imaging Corporation. Printed in USA. All rights reserved. Specifications are subject to change without notice. Contents may not be reproduced in whole or in part without the express prior written permission of Peripheral Imaging Corporation. Information furnished herein is believed to be accurate and reliable. However, no responsibility is assumed by Peripheral Imaging Corporation for its use nor for any infringement of patents or other rights granted by implication or otherwise under any patent or patent rights of Peripheral Imaging Corporation. Page 8 of 8 PI214MC-DR, 11/29/99