How To Deal with Rainbow Spots on Tempered Glass? The Causes And Treatment Methods

Rainbow spots on tempered glass generally refer to the appearance of rainbow like patterns on the glass, which are usually colored and show a circle of color changes spreading from the center to the edge. When the angle of sunlight refraction changes, it creates a bright visual field, also known as rainbow spots. Although rainbows are beautiful, rainbow spots affect the transparency of glass. So how to deal with rainbow spots on tempered glass? Below, I will explain the reasons and solutions for the emergence of rainbow spots on tempered glass.

1. Reasons for Rainbow Spots in Tempered Glass

1. Uneven stress distribution in tempered glass

The principle of glass tempering is to use ordinary glass raw materials to form compressive stress on the surface of the glass through tempering, heating and cooling, and to form tensile stress inside the glass. There are density differences from the surface to the center at different positions of the same surface layer. When the surface of the glass passes through a beam of polarized light, namely fast light and slow light, also known as birefringence phenomenon, when two beams of light formed at a certain point intersect with a beam of light formed at another point, there is a phase difference in the beam rubber pad due to the different speed of light propagation. At this point, the two beams of light form an interference phenomenon. When the amplitude and direction of the light are the same, the light is strengthened, and a bright field of view is visually generated, which is a rainbow spot. Therefore, tempered glass should be... The more uneven the force distribution, the more pronounced the rainbow spot phenomenon on the surface.

2. Moisturized and moldy, forming rainbow spots

During transportation, storage, and even installation and use of glass, due to the erosion of air, water vapor, or other chemical products, rainbow spots, white mist, and white spots are formed on the surface of the glass, causing a decrease in transparency and smoothness. In this case, the newly formed rainbow spots can be removed by cleaning with a solution. Cleaning with glass mold remover or 8% hydrofluoric acid can achieve good removal effects. If left untreated for a long time, it will be difficult to remove the rainbow spots on the glass.

2. Treatment method for rainbow spots on tempered glass

Based on the analysis of the causes of rainbow spots on tempered glass, how to deal with rainbow spots on tempered glass? In the early stage, improvements can be made by optimizing the tempering process during production, and in the later stage, the occurrence of rainbow spots can be avoided by strengthening the protection of glass during transportation and storage.

2.1. In terms of tempering processing

(1) To avoid and reduce the occurrence of rainbow spots after glass tempering, it is necessary to adjust the temperature of each area of the tempering furnace. When setting the heating temperature, the heat dissipation at the furnace edge should be considered to ensure that the temperature in each area is consistent and uniform. Otherwise, the surface compressive stress of the glass is smaller than the internal compressive stress, or the external compressive stress is larger but the internal compressive stress is smaller, resulting in uneven heating and rainbow spots.

(2) Ensure the accuracy of temperature sensors inside the tempering furnace, replace faulty temperature sensors in a timely manner, and replace non heating components in a timely manner to ensure accurate temperature control and heating effect.

(3) The rapid cooling treatment of the cooling section glass is very important for the formation of tempering stress. Therefore, it is necessary to ensure that all the blowing ports of the rapid cooling section air grille are unobstructed, the air ducts are not damaged or leaking, and the spacing between the aramid ropes is consistent to ensure the cooling effect. At the same time, the movement speed and airflow during the cold swing movement should be adjusted, and a small amplitude and high-frequency cold swing should be maintained to effectively reduce the occurrence of rainbow spots.

2.2. In terms of glass installation and use

(1) The installation angle can affect the polarization phenomenon of glass, and attention should be paid to the installation angle and observation angle. When observing the glass at an incident angle of 56 °, rainbow patterns are more obvious. Due to the more reflective surfaces and more polarized light, for tempered glass with the same uneven stress, the rainbow we see will appear more severe. Therefore, attention should be paid to the installation angle.

(2) Rainbow spots caused by moisture on glass can be effectively removed by cleaning with 8% hydrofluoric acid or glass mold remover if detected earlier. If the rainbow spots appear for a period of time but cannot be effectively treated, it will be difficult to remove them