2023-03-16

The night vision device can be used normally during the day？

Can night vision goggles be used during the day?

Can the night vision goggles be used during the day?

Can the night vision goggles be used during the day?

Why can't night vision goggles be used during the day?

Why can the night vision device be used normally during the day?

The general saying is that night vision devices cannot be used during the day, but what I want to say today is that not all night vision devices cannot be used during the day. Whether the night vision device can be used during the day depends on the specific type of night vision device.

1. Why the night vision device cannot be used during the day

In general, everyone says that night vision devices cannot be used during the day. This statement is somewhat inaccurate. It should be said that low-light night vision devices cannot be used during the day. The low-light night vision device is an image-enhancing tube night vision device. This type of night vision device is afraid of strong light during the day.

Before analyzing the answer to this question in detail, let's understand how the low-light night vision device works.

Above is the PVS31 made by MH Tech

The working principle of the low-light night vision device:

When the ambient light at night enters the night vision device through the objective lens of the night vision device, the first thing it encounters is a thing called a photocathode. The photon shines on it, and the electrons fly out, so that the light is converted into electricity. Under the action of the electric field, the electrons continue to move forward. The second layer is called a micro-channel plate, on which many small channels are evenly distributed, each channel is more than ten microns long, the distance between the channels is more than ten microns, and the channels are inclined at 8 degrees. This is a magical place. After electrons enter, they will collide with the channel. Each collision can knock out more electrons. New electrons continue to collide forward. The effect is that one electron enters and tens of thousands of electrons rush out. , so the signal is greatly enhanced. The army of electrons continues to rush to the third layer under the action of the electric field, and the third layer is a fluorescent screen. As long as the electrons hit it, it will emit fluorescence, and the electricity will turn back to light, and we can see the enhanced image.

So why are low-light night vision devices afraid of strong light during the day and cannot be used during the day?

The low-light night vision device includes four main components: objective lens, image intensifier, eyepiece, and power supply. The image intensifier tube is the core component of the low-light night vision device. The low-light night vision device is afraid of strong light because the image intensifier and low-light tube are afraid of strong light. Taking the image intensifier as an example, when infrared light is irradiated on the photocathode of the image intensifier, the photocathode emits electrons, and the electrons are accelerated to the fluorescent screen under the action of a high voltage field (16-21 kV) and an electronic lens, so that the fluorescent screen Displays the visible target image. The more light signals received by the image intensifier, the more electrons are emitted, the stronger the light signal from the fluorescent screen, and the brighter the image seen, they are basically proportional. However, if the external light is too strong, the number of electrons emitted by the photocathode will not increase to a certain extent, that is, saturation will occur, and the target will not be seen clearly. If too strong light suddenly shoots over, it may also burn out the photocathode of the tube, and cannot emit electrons, so nothing can be seen.

So far, the answer to why the low-light night vision device cannot be used during the day is very clear. Then why is there a saying that "Night vision devices can be used during the day"?

2. Why the night vision device can be used during the day

In fact, saying that night vision devices can be used during the day is also a misunderstanding of the concept of night vision devices. The night vision devices referred to in this statement should be digital night vision devices and thermal imagery night vision devices (also known as infrared thermal imagers), and do not represent all types of night vision devices. The low-light night vision device mentioned above cannot be used during the day. Digital night vision devices and thermal image night vision devices rely on image detectors to work, not image intensifier tubes. These two types of night vision devices can be used day and night 24 hours a day. So it is more accurate to say that digital night vision devices and thermal imagery night vision devices can be used during the day.

MH Tech is professional in researching and producing night vision devices, welcome you visit our factory and send inquiry to : 

Engineer Manager Name:  Jacky

WhatsApp/ Wechat:     0086-187 9245 6795

Email:     mh_elec@126.com or jacky@mh-elec.com