Compared to general rigid substrates, flexible substrates are more broadly used for they are windable, portable, secure, and widely applicable. However, flexible substrates also come with some disadvantages. For example, flexible substrates are not heat resistant or chemical resistant and offer low moisture and oxygen barrier properties and large coefficients of thermal expansion. A typical flexible substrate can be adopted for carrying electronic devices and/or packaging the electronic devices as a cover. Because a flexible substrate cannot completely obstruct the passage of moisture and oxygen, the moisture and oxygen will speed up the aging of the electronic devices on the flexible substrate and accordingly the lifespan of the electronic devices will be shortened undesirably.