1. Field of the Invention
This disclosure relates to a method of manufacturing a display device, and more particularly to a method of manufacturing a flexible display device.
2. Discussion of the Related Art
Recently, flat panel display (FPD) devices with light weight and thin size have been popularly and rapidly developed instead of cathode ray tubes (CRTs). The FPD devices include liquid crystal display (LCD) devices, field emission display (FED) devices, plasma display panels (PDPs), light emitting diode (LED) display devices, and others.
The FPD devices are almost generally manufactured through a high temperature process. As such, heat-resistant glass is used as substrates for the FPD devices. There is a limitation in reducing the thickness of the glass substrate. Additionally, although the glass substrate becomes thinner, the thin glass substrate without flexibility may be easily broken.
In view of this, a flexible display device has recently been proposed which employs a thin material with durability and flexibility, such as plastic, metal foil, and others, instead of the glass that lacks durability and flexibility, as its substrate. The flexible display device can constantly maintain a display performance even though it is bent as if paper is folded.
The use of a plastic or metal foil substrate thinner than the glass substrate forces the flexible display device to become thinner and more pliable in comparison with the FPD devices. The lower-price of the plastic or metal foil substrate compared to the glass substrate enables the flexible display device to be easily applied to various uses in comparison with the related art FPD devices. As such, the flexible display device has a good future as a next-generation display device. Accordingly, technologies of manufacturing the flexible display device have recently been actively developed.
On the other hand, the substrate of the flexible display device is easy to change during a manufacturing process due to its pliability. As such, it is very difficult for the pliable substrate to accurately perform the manufacturing process of the flexible display device. To address this matter, a manufacturing method of the flexible display device has been proposed which includes processes of fastening a flexible substrate to a support substrate using an adhesive material, forming display components on the flexible substrate, and then peeling off the flexible substrate from the support substrate.
FIGS. 1A to 1C are perspective views schematically explaining a flexible display device manufacturing method of the related art. Referring to FIGS. 1A to 1C, the related art method of manufacturing a flexible display device includes processes of fastening a flexible substrate 5 to a support substrate 1 by means of an adhesive material 3, forming circuit elements 7 on the flexible substrate 5, and then removing the adhesive material 3 and the support substrate 1 from the flexible substrate 5.
More specifically, the flexible substrate 5 is attached to the support substrate 1 using the adhesive material 3 as shown FIG. 1A. As such, the support substrate 1 stably supports the flexible substrate 5 which is firmly fastened to it by the adhesive material 3. Accordingly, the flexible substrate 5 can be easily handled.
Subsequently, display components 7 are formed on the flexible substrate 5 supported by the support substrate 1, as shown in FIG. 1B. The display components 7 are configured to include a variety of signal lines and a thin film transistor array. As such, the display components can be formed by repeatedly performing a patterning process which includes cleaning, thin film depositing, photo resist forming, etching, and others.
The adhesive material 3 and the support substrate 1 are removed from the flexible substrate on which the display components 7 including the signal lines and the thin film transistor array are formed, as shown in FIG. 1C. Therefore, the display components 7 are supported only by the flexible substrate 5.
The adhering process included in the related art method of manufacturing a flexible display device forces the flexible substrate 5 to be entirely adhered to the support substrate 1. As such, it makes it difficult to peel off the flexible substrate 5 from the support substrate 1. Also, the residuals of the adhesive material 3 can remain on the flexible substrate 5 after peeling off the flexible substrate 5 from the support substrate 1. Due to this, an additional cleaning process is necessary to remove the residuals of the adhesive material 3.
Moreover, the flexible substrate 5 must be bent by an upward force applied during the peeling off process which is included in the related art method of manufacturing the flexible display device. As such, some parts of the display components 7, such as thin film patterns, can be damaged when the flexible substrate 5 is peeled off from the support substrate 1. The thin film patterns damaged during the peeling off process cause the reliability of the flexible display device to be deteriorated.