PI627MC-A4 / PI628MC-A4 / PI629MC-A4 Engineering Data Sheet

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Functional Description

Each of the 3 modules consists of 27 PI3039 image sensors cascaded together. Each sensor consists of

192 photo-sensing elements (pixels), resulting in a module 5184 pixels long.

These image sensors have associated multiplex switches that are sequentially accessed with its digital shift

register. In addition, each has a chip-select switch that functions to activate its preceding sensor on the

cascaded sequence, after its predecessor chip has completed its scan. The start pulse initiates the shift

register of the first chip in all four sections. The first chip then sequentially clocks out the integrated image

charge from each pixel. These charges are passed through the sensors’ multiplexing switch and then out

onto the video line, where they are converted to a voltage. When the sensor completes its scan, the chip-

select switch on the following chip is switched on to continue the line scan until it completes its scan in one

section. A new scan is initiated when a start pulse is again entered into the first chip of each section.

The 27 sensors are cascaded together and bonded onto a PCB. The cascaded sensors are then divided

into 4 subsections, each subsection having its own output. The first 3 subsections contain 7 sensors and the

4

line capacitance, which are buffered by video amplifiers, to act as output drivers. The charge from each

output is integrated onto the video line capacitance and readout. Each pixel is then reset and ready to

integrate again.

Mounted in the module is a one-to-one graded indexed micro lens array that focuses the scanned

documents to be imaged onto its sensing plane.

Illumination is by means of an integrated LED light source. The particular Led for each module is listed in

Table 1

Module

LED Type

PI627MC-A4

660nm Red LED Bar

PI628MC-A4

High power Yellow-Green LED Bar

PI629MC-A4

Low power Yellow-Green LED Bar

Table 1. Module vs LED Light Source

All components are housed in a small plastic housing which has a glass cover that acts as the focal point for

the object being scanned and protects the imaging array, micro lens assembly, and LED light source from

dust.

Figures 1 and 2 on page 4 show a block diagram and a cross section of a module.

Page 3 of 13, Revised 2-23-04