One-way bullet-proof glass is usually made into two layers: a fragile layer on the outside and a flexible layer on the inside. When a bullet is fired from the outside, the bullet will hit the fragile layer first and break an area. This will absorb the kinetic energy of some bullets and spread kinetic energy in a larger area. When the slowing bullet hits a flexible layer, it is blocked. However, when the bullet shoots from the inside, it will hit the first layer of flexibility. The bullet can break through the pliable layer because its energy is concentrated in a small area, and the crisp layer breaks outward when the flexible layer projects outward, and does not hinder the progress of the bullet.
The bullet-proof glass is a glass that has the ability to protect the gun shot while having the transmissive and transmissive properties of the glass. The bulletproof principle of bulletproof glass is that it can convert the impact kinetic energy of the bullet into the elastic potential energy of the glass and the surface energy of the debris.