How Does Night Vision Work: A Hands-On Look at Digital Night Vision

This article explains how humans and animals achieve night vision,
with a focus on digital night vision,
including their strengths and drawbacks.

If you simply want to get a visual idea of what digital night vision looks like,
just check out this article:
Best Digital Night Vision Binoculars Under $300.

To help you understand better,
CIGMAN even gives a hands-on demonstration by taking apart a digital night vision device!

Through plenty of images and clear explanations,
we'll help you quickly and truly grasp how digital night vision works.

Written by CIGMAN 
Published on August 22 2025

Night Vision of Humans and Animals

Firstly, let's talk about the night vision system of humans and animals.

In the dark, human eyes rely mainly on a type of rod cell to see objects, which can only barely maintain an image. Because our eyes cannot emit light on their own, they can only rely on ambient light such as moonlight, starlight, or distant street lights.

Therefore, in dark environments, vision becomes slow, grainy, and almost black and white^[1].

Like animals, cats are much better. The reflective layer (tapetum lucidum) in their eyes reflects light back to the retina, giving the rod cells a second chance to capture light, which means they can collect more light sources and improve clarity even in extremely low light conditions^[2].

Therefore, cats have the ability to see at night.

Owls go a step further. Their eyeballs are large tubular, with abundant rod cells and a structure similar to the reflective layer, which can provide excellent low-light sensitivity and contrast, equivalent to the night vision of humans and cats magnified several times. Their night vision is very good.

However, the color and depth of the field cannot be restored. What they see is a black and white, high-definition scene that is flatter than real life^[3].

How Do Image Intensification,
Or Traditional Optical Night Vision Goggles, Work?

Many people may not know that modern digital and thermal imaging systems are derived from traditional optical image intensification. Its principle is that the night vision tube collects weak visible light and near-infrared light through the objective lens. The collected light photons hit the photocathode and excite electrons; then the electrons are multiplied in the microchannel plate, and the fluorescent screen converts the electron cascade into a bright green image^[4].

This type of imaging has extremely low latency and a natural look, making it very suitable for dynamic movement when worn on the head. However, they cannot see clearly in a completely dark environment and still require a certain amount of ambient light as a supplement, such as moonlight and starlight.

Infrared supplementary light is also needed in a completely dark environment, but military night vision goggles generally supplement with 940nm invisible infrared light, which is very concealed and not easily discovered by humans and animals.

The current technology has developed to the fourth generation. This technology is currently used by the military and is not public. The industry classifies Gen‑3 and Gen‑4 as military night vision devices. Their night vision enhancement tubes are expensive, so the price is more than ten times that of civilian night vision devices. Moreover, with the current known technology, they are still not completely concealed. The green halo of some devices may reveal the location^[4].

What's The Inside of Digital Night Vision Device?
How Does a Digital Night Vision Device Work?

01 Aluminum Alloy Fixing Plate/Bracket

That thin silver plate is a component made of polished aluminum alloy, primarily used to secure and support the optical lens.

Because it's made of alloy, it offers a certain degree of thermal conductivity while also being extremely strong and durable, helping to dissipate heat from the night vision lens and maintain internal stability.In addition to its excellent thermal conductivity, it's also lighter than traditional materials.

If it were too heavy, it would be difficult to lift. Therefore, a high-quality aluminum alloy fixing plate must be both extremely thin and sufficiently strong.

02 Infrared Filter

Infrared filters are generally made of optical glass or resin coatings. They are primarily used to control the transmittance of infrared or visible light and help the imaging sensor filter out unwanted wavelengths, improving the signal-to-noise ratio and ultimately enhancing night vision image clarity.

Optical glass filters are commonly used in expensive military night vision devices. Their surface utilizes a multi-layer interference coating technology that precisely controls the separation of infrared and visible light. In addition to the coating, glass also boasts high and uniform light transmittance, which significantly aids imaging and indirectly reduces noise and improves image purity.

Furthermore, glass is hard, scratch-resistant, and highly resistant to temperature fluctuations and humidity, making it more suitable for complex environments.Of course, this obviously requires high craftsmanship, making it expensive and relatively heavy.

Resin-based filters, on the other hand, are lightweight, low-cost, and highly malleable, making them suitable for use in portable or consumer night vision devices.

They are typically made by applying multiple layers of optical coating to a resin substrate to selectively transmit or reflect infrared wavelengths, which can also achieve a certain degree of effectiveness. Their advantage lies in their impact resistance and resistance to shattering.

However, their heat resistance, aging resistance, and optical stability are slightly inferior to those of optical glass, so their service life is not as long as that of optical devices. Slight deformation or transmittance changes may occur over time. This depends primarily on the frequency of use.

So, with proper care, normal usage frequency is not excessive.

03 Main Control Circuit Board(MCU)

The MCU board functions for night vision goggles similarly to the CPU for computers: it's the brains of the device, responsible for image processing, infrared gain control, data storage, and display driving.

It consists of a fiberglass PCB (FR4) and electronic components (ICs, capacitors, and resistors).

The quality and size of these components and chips determine the overall imaging quality of the device and, of course, at least 60% of the cost.

04 Binocular Display Module

The binocular display module primarily consists of an OLED/LCD screen and a plastic (alloy) package. It displays the processed night vision image, allowing the user to see the enhanced image simultaneously with both eyes.

It's important to note that display resolution doesn't completely equate to image quality; it represents the quality of the display.

05 Infrared Magnifying Optical Lens
            Objective Lens Assembly

Next comes the infrared magnifying optical lens and objective lens assembly. They typically consist of optical glass and an aluminum alloy or plastic housing, and are connected to the wiring.

It's primarily designed to focus infrared light, concentrating weak signals onto the photosensitive chip.

If equipped with an 850nm infrared module, it's visible; if equipped with a 940nm module, it's invisible. Of course, the 940nm module is more expensive.

06 Photosensitive Sensor Module (CMOS/CCD)

Next is the CMOS photosensitive module, consisting of a silicon chip and a PCB baseboard.

It captures nighttime light and infrared reflections, converting them into electrical signals for the mainboard to digitally process.

Think of it as a signal translator; if high quality, it's both accurate and fast.

07 Main Processing Board / Video Signal Board

This massive device, consisting of a multilayer PCB (FR4 substrate) and soldered chips (DSP, memory IC), is primarily responsible for image processing for night vision goggles.

It's like a vintage film camera, requiring a photographer to go undercover to develop the film. It's primarily responsible for image digital signal processing, video output, and data interface control.

If processed well, it can reproduce lifelike images.

08 Display Module Cable (FPC Cable)

Digital product screen connections typically use PI and copper foil cables, and night vision devices are no exception.

This component connects the main control board to the display, enabling signal and power transmission.

PI is heat-resistant, durable, and remarkably durable, resisting deformation and chemical resistance.

Copper foil is highly conductive and easy to weld, allowing for very thin cables and withstanding repeated bending.

Simply put, the combination of the two is thin and stable, capable of high speed and density, with mature manufacturing processes and manageable costs.

09 Lithium Polymer Battery

Finally, let's talk about batteries.

I've already explained in detail in this blog post the types of batteries commonly used in night vision goggles, their performance, and suitable equipment.
You can check it out here: Night Vision Goggle Batteries: Type, Power Options and Practical Tips

Today, I'll focus on lithium batteries: aluminum-plastic film + lithium-ion cells (graphite, lithium cobalt oxide).

Lithium batteries typically have a capacity between 1000–3000 mAh, supporting several hours of heavy use and more than ten hours of battery life. This is why many military night vision goggles have external batteries, allowing them to be used outdoors for days.

To summarize, night vision devices, especially digital night vision goggles, primarily consist of optical acquisition, signal capture and digital enhancement, image presentation, and battery charging. These functions are implemented using the 9 components listed above, arranged into 9 functional modules.

This is how Night Vision Works.

Compared to traditional, expensive optical military night vision devices, these devices differ primarily in their 6 modules: optical acquisition, signal capture and conversion, image enhancement and display, power supply and control, image storage and transmission, and control interaction and system expansion.

They do not utilize digital signal processing, but instead rely on a photocathode, microchannel plate, and phosphor screen to form a complete optical-electronic amplification chain.

As a result, their image quality, brightness, and stability far surpass those of digital night vision devices, especially under conditions of sustained movement or vibration.

Finally, there are some night vision goggles' shell materials (see the picture above).

In addition, brands generally provide some night vision goggles with accessories, which are generally designed for outdoor and tactical games. Common ones include compasses, tactical flashlights, tripods, etc.

What's Digital Night Vision?

Digital night vision replaces the tube with a high-sensitivity CMOS or CCD sensor. It captures what little light is there, processes it, and displays the result on an LCD screen or eyepiece.

Digital night vision devices are light, possibly aided by IR illumination, hits a back-illuminated or sCMOS sensor. The sensor records the image in pixel form. Software boosts brightness, contrast, reduces noise, and displays it in green, grayscale, or other colors.

How Digital Night Vision Outperforms Traditional Systems?

As shown in the component breakdown above, digital night vision devices are built around nine key functional modules.

Many assume that optical night vision units are better just because they cost more. But that’s not always the case.

In fact, in several areas of modern imaging and processing technology, digital night vision can even surpass military optical systems.

Conclusion

Night vision is no longer just for professionals.

Digital systems keep getting sharper, faster, and truer to color. Whether you're a soldier in the field, a firefighter in a room filled with smoke, a wildlife researcher in a dense forest, or simply curious about what moves in the dark, there's gear made for you.

References

[1] D. Purves et al., Neuroscience, 2nd ed. Bethesda, MD, USA: Sinauer Associates via NCBI Bookshelf, 2001. [Online]. Available:https://www.ncbi.nlm.nih.gov/books/NBK10982/. Accessed: 24 Oct. 2025.

[2] F. J. Ollivier, D. A. Samuelson, D. E. Brooks, M. L. Lewis, and K. A. Kallberg, “Comparative morphology of the tapetum lucidum,” Vet. Ophthalmol., vol. 7, no. 1, pp. 11–22, 2004, doi: 10.1111/j.1463-5224.2004.00318.x. [Online]. Available: https://onlinelibrary.wiley.com/doi/10.1111/j.1463-5224.2004.00318.x.

[3] G. R. Martin, “An owl's eye: Schematic optics and visual performance in Strix aluco L.,” J. Comp. Physiol., vol. 145, no. 3, pp. 341–349, 1982, doi: 10.1007/BF00619338. [Online]. Available: https://link.springer.com/article/10.1007/BF00619338.

[4] S. Mahlke, D. Rösler, K. Seifert, J. F. Krems, and M. Thüring, “Evaluation of six night vision enhancement systems: Qualitative and quantitative support for intelligent image processing,” Hum. Factors, vol. 49, no. 3, pp. 518–531, 2007, doi: 10.1518/001872007X200148. [Online]. Available: https://www.researchgate.net/publication/6285027.

Why Choose CIGMAN
As Your First Night Vision Goggles Brand?

1. CIGMAN specializes in laser electrical measurement and night vision tools that help users solve problems quickly in both professional and daily settings.
2. CIGMAN's products are safe, compliant, eco-friendly, user-friendly, and meet international standards with patented designs.
3. CIGMAN's products have been sold to more than 30 countries with more than 10,000,000 products.
4. CIGMAN insists on providing customers with high-quality products and promise to provide customers with 36-month worry-free after-sales service.