The following difficulties and cost problems exist in the production process of OLED:

1. Control of moisture and oxygen: During the OLED manufacturing process, moisture and oxygen will seriously affect the quality of the film, so it is necessary to strictly control the moisture and oxygen content in the production environment to ensure the quality of the product.

2. Transfer technology: One of the main difficulties in OLED manufacturing lies in the transfer technology of OLED thin films. Usually, OLED thin films need to be transferred at different stages of the production process, and this link has very high requirements for equipment and technology, which will also increase production costs.

3. Purity and stability of materials: The production of OLEDs requires highly pure and stable organic materials. The production costs of these materials are very high, which limits the large-scale production and application of OLEDs.

4. High cost of manufacturing equipment: At present, manufacturing high-quality OLEDs requires expensive production equipment, which is one of the reasons for the high cost of OLED production.

5. Lifespan issue: Although the image quality of OLED is high, its lifespan is not long enough. Some OLED products may have "drunkenness" phenomenon, which causes burning or darkening of the image.

In short, OLED production is costly and technically difficult, but this does not prevent it from becoming the mainstream trend of future display technology.