Display modules
An electronic device may have a display. The display may have active components such as display pixels formed on a display substrate layer. The display substrate layer may be formed from a glass substrate layer. Thin-film transistors and other components for the display pixels may be formed on the glass substrate. An encapsulation glass layer may be bonded to the glass substrate using a ring-shaped bond structure. The ring-shaped bond structure may extend around the periphery of the encapsulation glass layer and the substrate glass layer. The bond structure may be formed from a glass frit, a solid glass ring, integral raised glass portions of the glass layers, meltable metal alloys, or other bond materials. Chemical and physical processing operations may be used to temper the glass layers, to perform annealing operations, to preheat the glass layers, and to promote adhesion.
1. A method for forming a display module, comprising:
forming an integral ring-shaped raised ridge around a peripheral portion in a first layer of glass on which electrical components are formed;
bonding a second layer of glass to the integral raised ridge in the first layer of glass to encapsulate the electrical components, comprising:
applying localized heat from a first heat source to the integral raised ridge in the first layer of glass; and
applying global heat from a second heat source to all of the first layer of glass.
2. A method for forming a display module, comprising:
forming an integral ring-shaped raised ridge using soda lime around a peripheral portion in a first layer of glass on which electrical components are formed; and
bonding a second layer of glass to the integral raised ridge in the first layer of glass to encapsulate the electrical components.
3. The method defined in claim 1 , further comprising forming an integral ring-shaped raised ridge around a peripheral portion in the second layer of glass that mates with the integral ring-shaped raised ridge in the first layer of glass.
4. The method defined in claim 1 further comprising tempering the first layer of glass.
5. The method defined in claim 1 further comprising annealing the first and second layers of glass.
6. The method defined in claim 2 , further comprising:
processing a glass frit formed of frit particles having edges to smooth the edges; and
depositing the glass frit around the periphery of the first layer of glass, and wherein bonding the second layer of glass to the integral raised ridge in the first layer of glass comprises:
applying light to the glass frit; and
before applying the light to the glass frit, heating an area of the second layer of glass that does not contact the glass frit using a heating element that contacts the area of the second layer of glass.
7. The method in claim 2 , further comprising bonding a solid ring-shaped gasket between the first and second layers of glass.
8. The method defined in claim 2 , further comprising filtering the glass frit by frit diameter before depositing the glass frit.
9. The method of claim 2 further comprising tempering the first layer of glass by coating the first layer of glass with a potassium-based paste and applying heat to the first layer of glass.
10. The method in claim 2 , wherein heating the area of the second layer of glass that does not contact the frit further comprises heating the area of the second layer of glass with a heated chuck.
11. The method in claim 2 , further comprising cooling the second layer of glass.