Quantum Dot Wavelength Conversion Laminate for End-Surface Discoloration

The patent applies preliminary action by forming modification parts at the end surfaces of the wavelength conversion layer and barrier layers before the discoloration problem occurs. These modification parts are created through laser beam irradiation or thermal treatment, which pre-treats the end surfaces to prevent moisture intrusion and subsequent discoloration of the quantum dots during the product's service life.

The modification parts act as an intermediary barrier between the moisture environment and the quantum dots. By creating these modified regions at the end surfaces, the patent introduces a protective intermediate layer that prevents direct contact between moisture and the quantum dots, thereby preventing discoloration while maintaining the wavelength conversion function.

The patent converts the harmful effect of laser beam irradiation (which creates moisture intrusion pathways) into a beneficial effect by controlling the irradiation parameters to create modification parts with enhanced barrier properties. The same laser beam that causes cutting also creates a modified region that, when properly controlled, reduces moisture permeability and prevents future moisture intrusion at the cut surfaces.

The patent applies parameter changes by carefully controlling the laser beam frequency (5 kHz to 30 kHz), scanning speed (50 mm/s to 100 mm/s), and output power (3.4 W to 100 W) to optimize the modification process. These parameter adjustments ensure that the modification parts are created with sufficient depth and density to block moisture intrusion while maintaining clean cuts.