CMOS image sensor test

When CMOS technology came out in the 1980s, the semiconductor industry grew by a huge amount. Transistors are now cheaper, smaller, faster, and use less electricity. It is the CMOS image sensor test that has made it possible for chips to have very high integration, which has led to modern high-performance integrated circuits that are smaller but still work well. Aside from helping to make integrated circuits smaller, CMOS technology has also been used in sensing applications.

CMOS technology is used to make sensors, especially in the imaging field. Because CMOS-based image sensors are so common, “CMOS” sensors are often used as a synonym for ” CMOS-based image sensors.” CMOS-based image sensors have become a competitor to CCD-based image sensors.

In the sections that follow, we’ll talk about both CCD and CMOS sensor-based imagers, their pros and cons, and how they can be used. Also, other ways that CMOS technology can be used in the field of sensing will be discussed.

Working on the CMOS Image Sensor Test

A typical CMOS is an integrated circuit with a number of pixel sensors. In CMOS sensors, each pixel has its own light sensor, amplifier, and pixel select switch. This is not the case with CCD sensors. On the CMOS sensor are an analog-to-digital converter and other important parts for how the pixel sensors work.

The CMOS image sensor test has four main parts: the colour filters, the pixel array, the digital controller, and the analog-to-digital converter.

• Color filter

The colour filter is the same as what was said about the CCD-based imager.

• Pixel Array

As with a CCD, the pixel array’s job is to measure how bright the light that passes through it. Each pixel sensor turns the amount of light coming in into a voltage signal, which is then sent to the ADC to be processed further.

Active Pixel Sensors (APS) and Passive Pixel Sensors (PPS) are the two types of architecture for Pixel sensors (APS).

In passive pixel sensors, only one photodetector is used per pixel, and there is no local amplifier. In active pixel sensors, however, 3–4 transistors are used per pixel.

Passive Pixel sensors have bigger fill factors and smaller pixels, but they are slow and have a low SNR. Active pixel sensors, on the other hand, are fast and have a good SNR but larger pixels and a low fill factor.

But because CMOS technology has improved and shrunk down to nm, pixel size/fill factor is no longer a big deal. Instead, APS is the preferred technology and is used in most devices.


The ADC takes the analogue voltage signals from the pixel sensor array and turns them into a digital signal.

• Digital Controller

The digital controller is in charge of how the CMOS image sensor test works. It controls the pixel array, makes sure that all pixels are in sync, etc.

Operations of CMOS Sensors

  1. Pixel sensor works like a charge bucket; it stores electron charges the same way a water bucket stores water.
  2. Charge is turned into voltage and made stronger at the pixel.
  3. Each CMOS micro wire carries voltage from one pixel at a time. The pixel select switch tells the microwires which pixel to carry voltage from.
  4. The following steps are taken to send a video signal:
  • 1. All of the pixel select switches are on. The voltage from each pixel is sent to the column circuit by this.
  • 2. From left to right, you turn on column select switches. So, the signal voltages of each pixel in the same row are sent out in the order they were received.
  • 3. This is done for each row in order from the top to the bottom. The signal voltages of all pixels can be sent out of the image sensor from the top left corner to the bottom right corner.
  1. These voltages are sent from the camera’s signal processor to the camera’s signal processor.

By Admin

Leave a Reply

Your email address will not be published. Required fields are marked *