A comprehensive resource for safe and responsible laser use

Hong Kong: Conviction upheld based on laser pointer being an offensive weapon

On May 20 2020, a Hong Kong judge upheld the conviction of a 16-year-old boy for possessing a laser pointer during September 2019 protests. Under Hong Kong law, laser pointers can be classified as offensive weapons.

In November 2019 the unnamed teenager was the first protester to be found guilty of carrying a laser pointer as an offensive weapon. He was sentenced to a rehabilitation center for three months.

During his May 2020 appeal, defense counsel said the laser pointer could have been used peacefully to point at buildings and draw attention. Counsel further said there was no evidence the teen had used the pointer, and that he had been cooperative with police.

However, the appeals judge agreed with prosecutors at the November 2019 trial. They said the teen was wearing protest gear including a helmet and he must have intended to use it to inflict harm or discomfort upon others. The judge also noted the teen did not present evidence or testify to contradict the prosecutors' claims.

The judge also said that using laser pointers on buildings for peaceful protest was "a fanciful notion".

A government expert testified that the laser device could cause harm if it were pointed at the human eye within a distance of 36 meters (118 feet).

From the South China Morning Post


The 36 meter "ocular damage" distance probably refers to the laser's Nominal Ocular Hazard Distance. For a handheld laser with a typical beam of 1 milliradian beam spread, this corresponds to a laser of roughly 25 milliwatts. (The laser color would not be a factor in injury, only the power and divergence.)

In many countries the legal limit for a laser pointer is 1 mW; in the U.S. pointers of up to 5 mW are allowed to be sold.

A NOHD of 36 meters does not mean that injury will occur at that distance. As explained elsewhere, there is a safety or reduction factor built into the NOHD. At around 12 meters (39 feet), a 25 mW 1 mrad beam with a nominal 1/4 second exposure could cause the smallest detectable change in the retina about half the time, under laboratory conditions. Beyond 12 meters the chance of injury becomes even less until at the 36 meter NOHD it is considered an allowable exposure.

A one-quarter second exposure is used in the laser safety field for cases of accidental or unwanted beams. A person will blink, move or otherwise avoid eye exposure the laser light within that time.