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Using CIS Scanners for Document Scanning

Types of Document Scanning Sensors

What do you value when it comes to your scanning solution? The quality of the image? Whether the solution is within your budget? How feasible the sensor is to apply in your system? The environmental impact your system will have?

Which sensor is your flatbed document scanner based on?

Different sensor technologies provide you with different benefits. The two technologies commonly used for document scanning are CCD and CIS.

Charged Coupled Devices (CCD Scanner)

CCD scanners, also known as Charged Coupled Devices are a legacy scanning technology.

CCD scanners diagram for document scanning.

Some benefits to utilizing a CCD sensor in your scanner include a flexible working distance (the distance between the scanned object and your scanner), achieving a quality scan as document scanners typically do not have to capture something quick in motion (a downside of CCD sensors is that they fare worse capturing objects quick in motion).

Some downsides are: Greater power consumption requirement and optical distortions depending on lens-type chosen.

Contact Image Sensors (CIS Scanner)

The reason why many scanner manufacturers are migrating from CCD to using CIS has to do with the increasing quality of CIS scans and increasing affordability of CIS.

Contact Image Sensors for document scanning.

A downside of the CIS scanner is that the working distance ranges are narrower. CMOS Sensor Inc works closely with clients to ensure that the focal working distance results in picture perfect images.

Contact image sensors are more compact and lightweight, they allow for capturing wider documents, and have lower power consumption needs, allowing your solution to be environmentally friendly, sustainable, and eco-friendly. They also do not risk lens distortions that CCD scanners sometimes have.


Recommended Contact Image Sensor for Flatbed Document Scanning: M116-A3C3

CMOS Sensor Inc, from 25+ years of experience in imaging, highly recommends the M116-A3C3 contact image sensor for flatbed scanners because the M116-A3C3 has been tailored for wide document color scan applications based on many years of client feedback and iterations.

M116-A3C3 scanner module for document scanners.

Image quality is important when it comes to document scanning and the M116-A3C3 has delivered on this front. Expect your solution to reliably achieve high-resolution 1:1 precision color scans from the SELFOC Lens Array (SLA).

This module uses CMOS Sensor Inc's exceptionally sensitive C116 silicon, with sensitivity of over 300 volts/lux second. This sensitivity is enabled by a 2,500 sq micron of sensor area for every pixel.

The M116-A3C3 is over 12 inches long, with over 7,200 pixels. Thus, your 36-inch scanner will only require 3 sensors.

A 300 or 600 dpi high-resolution ensures that items are imaged impeccably.

Low power consumption helps your solution be environmentally friendly.

M116-A3C3 Contact Image Sensor:

Greatly Reducing Shading Errors Through Proper Illumination

One of the most important factors in image acquisition quality is the lighting.


For this reason, the CIS module compliments the C116 silicon with a unique built-in light source that provides up to 50 times greater illumination than most other approaches. 

M116-A3C3 scanner built in light source

Historically, CIS scanners have had issues with wrinkles and fold lines on the scanned page due to lack of depth.

The M116-A3C3 scanner's lighting method nearly eliminates shading errors, a typical CIS scanner challenge with creased or wrinkled documents.

Its proper lighting ensures high signal-to-noise ratio and an excellent dynamic range. Which is the reason for CMOS Sensor Inc's high recommendation.

When contacting CMOS Sensor Inc for CIS optimized for document scanning applications, specify the M116-A3C3.

Other Sensors for Document Scanners:

M206-A3C CIS - CMOS Sensor Inc's legacy document scanner sensor supports 300 or 600 DPI resolution, 344 pixels, a length adjustable to your project's needs (reaching over 12 inches), RGB color-imaging scanning, and 10M pixel rate, the M206-A3C CIS is also a solid module to scan documents with.

It is recommended primarily for cost-effective document scanning.


  • 300 / 600 DPI resolution

  • 344 pixels

  • Built-in RGB LEDs for color scans

  • Sensitivity of over 300 volts/lux second

  • 300 µsec/line


  • Over 12 inches of scanning length

  • Dual-illumination for improved signal-to-noise ratio

  • Reduced scanner cost and complexity

  • Low power consumption

  • All aluminum construction

Other Contact Image Sensor Modules for document scanning.

Industrial Proximity Linear - If you are looking for a camera for heavy-duty industrial document scanning, the IPL would be a better choice as it works through FPGA and a Camera Link Cable to capture and deliver a full resolution 1:1 accurate image with no lens distortions found with conventional camera setups.

We recommended the IPL for large-format flat-surface scanning, Automated Optical Inspection, and machine vision setups.

Industrial Proximity Linear camera for heavy duty scanning.
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CMOS Sensor Inc's Dedication to Your High-Quality Scans:

Your document processing products are used to archive, print, process, convert, duplicate, communicate, and broadcast high-quality images.  

CMOS Sensor Inc based modules are expected to supply reliable scanning solutions.

When the little details are important, you can count on CMOS Sensor Inc. to produce a high-definition image at the speed you need to fulfill your mission. 

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