We all know that for some medical lasers, laser diodes require high performance parameters, and for power, the required power will be very small. Many people ask what the concepts of laser diode 3R and 3B are, and can Korean QSI laser diode be satisfied?

1. What do you mean by level 3R vs level 3B?

These two levels are actually laser safety levels, not the structural levels inside the chip. Simply put, it is a classification that evaluates the potential harm to human body (especially eyes) according to laser output power, wavelength, duration/pulse and other parameters.

Class 3R for visible light continuous wave, the output is about 1 ~ 5 MW (depending on the standard and wavelength). It may be harmful to directly look at the beam (especially if it is amplified by instruments), but usually short time and natural reaction (blinking and moving away) can avoid serious injury. The risk of reflection (especially diffuse reflection) is low.

Class 3B For continuous wave, in the visible light or near infrared range, the power may be in the range of several mW to several hundred mW (depending on the specific standard and wavelength), which is extremely harmful to the eyes; Reflected light (if it is specular/strongly reflective) may also be dangerous; Diffuse reflection is usually less risky, but it cannot be completely ignored.

Comparison and influence 3B allows greater output power, while 3R is tighter. Therefore, when making instruments and modules, which level should be used to meet the safety rules, add protection, lock, warning and other daily laser pens, and most low-power detection modules may be 3r; Industry, scientific research and cutting may enter the category of 3B or higher.

Therefore, "3R" and "3B" are not the labels of good or bad chips, but the labels of "which level this laser belongs to in safety and how risky it is".

Second, the ability of QSI in this level

QSI has product lines in the directions of red light, near-infrared laser diode and optical communication/sensor.

In the red light (such as 635 nm to 680 nm) range, they have some models with output power of 5 mW, 10 mW or even higher.

In the infrared (IR, such as 780nm ~ 940nm) range, there are also product lines with power ranging from several mW to several tens/hundreds mW.

I see that there are "5 mW, 10 mW" types in QSI's product line, which are typical power in the 3R/3B boundary area.

There is a small factory that does laser ranging/laser sensing. They originally used a domestic low-power red laser, and the product was protected by 3R level (that is to say, the user will not have a higher risk in theory). Later, in order to improve the ranging performance, they raised the laser power to make the detection distance longer. In this way, the output power of the new laser exceeds the original safe upper limit of 3R and enters the 3B range. Results In an internal test, an engineer misused a magnifying glass or visual way to observe the light spot, which almost damaged the retina. Later, manufacturers had to add stricter safety protection: add a hood, add a key switch, clearly warn in the user manual, and force to wear protective glasses. At that time, I realized: "Although the power upgrade improves the performance, the security level immediately jumps to a higher level, and the design/certification/user security risks brought by it also rise a lot."

Therefore, when choosing QSI or other manufacturers' diodes/modules, we should not only look at the power and cost, but also consider "what is the safety level of this laser to the user and what regulations/standards/certification/safety design should be met".