This blog post provides an easy-to-understand explanation of the current state and future potential of flexible display technology.
Computers that can be worn like clothes, electronic paper that can be folded and rolled up like newspapers, multifunctional electronic skin that can be attached to the body to monitor health, and other futuristic items depicted in science fiction movies and novels are being developed by scientists and engineers. These items share a common feature: they are flexible electronic devices.
Flexible devices have the potential to revolutionize the form and use of electronic devices we use in our daily lives. Displays, which are devices that visually convey information from electronic devices, are core components of electronic devices, and the information transmission function of displays is expected to expand further in the future. Flexible devices also require displays, and various research institutes and companies are striving to secure technology for flexible displays. As of 2024, Samsung and Lenovo have announced new foldable smartphones and rollable laptops equipped with bendable displays. These devices present new possibilities that go beyond the form and functions of existing smartphones and tablets.
Flexible displays have several advantages. Curved TVs reduce distortion by reducing the distance between the center and the edges, thereby greatly increasing the viewing angle. Curved displays on smartwatches make them more comfortable to wear. Foldable smartphones allow the screen size to be changed according to the situation. You can fold it up and carry it around with you, and then watch movies on a large screen at home. Talkable e-paper has the added advantage of being less breakable. This is because if it can talk, it needs to be less breakable. Talkable smartphones can be made to be worn like smartwatches.
How are flexible displays classified? There are various types of displays, but according to Kimberly Allen, they can be broadly classified into three categories. The first type is displays that are not flat but cannot be reshaped, such as Galaxy Edge smartphones and curved monitors. These products are already commercially available. The second type is a more advanced form of display that can only be folded once and has limited reshaping capabilities. It is used in products such as e-books that fold in half. Although these displays are technically commercializable, it is more economical to use two separate displays. The third type is products that can be freely transformed, such as paper, which is the pinnacle of flexible displays. This technology is used in products that can be rolled up for storage or worn like clothing.
It can be classified as a substrate material for electronic products. The materials are mainly glass, plastic, and metal. Glass has several advantages over plastic. Glass is highly transparent because it has been the main material for optical components. Glass is stable at high temperatures and highly resistant to chemical reactions. Other organic materials are attacked by water and oxygen and undergo deformation, but glass has low permeability and can be used as a barrier. It is scratch-resistant and does not get scratched, so it is used for touch panels.
Generally, people do not think that glass is flexible. This is because the glass we commonly see is easily broken. However, it is possible to manufacture flexible glass. Flexible glass must be less than 200 μm thick. When the force is the same, mechanical pressure is inversely proportional to the square of the thickness, so thin glass plates are more fragile than thick glass plates. In addition, the substrate is designed to bend, which requires even greater stability. Methods to prevent glass from breaking include surface hardening, multi-layering, and using synthetic glass. These methods are all applied to thick glass or reduce the degree of bending. The remaining method is to strengthen the glass by coating it. Coating reduces the impact of existing defects and reduces the degree of breakage, making it an effective method.
Although there are cases where displays are not necessary, such as electronic skin, displays are essential for general smart watches, wearable computers, and electronic newspapers. Flexible displays can further enhance the advantages of these devices. Glass, which is a material necessary for making touch panels, can be made thin and coated for use in flexible displays.
Products that use displays that can be rolled up and stored like in movies and novels have not yet been commercialized. To commercialize them, bendable displays alone are not enough. Electronic circuits, processors, batteries, memory, and even communication devices and the boards and cases that house them must all be bendable, or other solutions to overcome bending must be found. Even if a solution is found, the work is not over. The product must be durable enough to withstand deformation without breaking. A new manufacturing process must also be developed to enable mass production of the resulting product. Manufacturing flexible displays requires a significant investment. These technologies will not disappear unless products are created that consumers are willing to pay high prices for. It is necessary to go beyond the application of existing products and come up with revolutionary new products.
In addition, economic aspects are also important for the commercialization of flexible display technology. Since technology development is costly, the economic burden on consumers who purchase the product must also be considered when it is commercialized. Companies must not only develop products based on innovative technologies, but also make them economically attractive. This process requires an overall strategy from the initial stages of technology development to commercialization, which has a significant impact on the competitiveness of companies.
What kinds of displays will there be in the future? Currently, projectors require a screen, such as a wall, in order to be viewed. Some smart watches project images onto the hand or arm. In the future, projectors may be used in empty spaces, creating a world where displays themselves are no longer necessary. There are also methods of delivering audiovisual information by directly stimulating the brain. This is a form of augmented reality. The displays of the future may be nothing other than our own brains.
