## 3 Results and Discussion
### Prototype 3  
Figure 10 shows Prototype 3, which is an amalgamation of the designs of Prototypes 1 and 2. Figure 11 presents the slider cover of Prototype 3. In order to increase the distance between the phone and our head during phone conversations while remaining user-friendly when not having a phone conversation, a slider cover is made based on the TRIZ contradiction matrix--Dynamics. Users can slide the slider to 90 degrees, which is perpendicular to the ear speaker, in order to increase the distance during a phone conversation. After the phone conversation, users can slide the slider back to 0 degrees, which is located on top of the phone. Figure 12 shows the stopper added to the slider cover of Prototype 3. In order to prevent the slider cover of Prototype 3 from sliding off while also not worsening the durability during phone conversations, a stopper is added based on the TRIZ contradiction matrix--Local Quality. After adding the stopper, the cover part of the slider can firmly stand at 90 degrees while our ear is in contact with the cover part during phone conversations. Figure 13 presents the small holes added to the slider cover of the prototype. In order to enhance the clarity of the ear speaker during phone conversations while also not worsening the reliability, small holes are added in the slider cover based on the TRIZ contradiction matrix--Porous materials. Several holes are added to the slider cover, which is perpendicular to the ear speaker, so that the sound can pass through these small holes and enhance the clarity of the speaker. Figure 11: Slider cover of Prototype 3 at 0 and 90 degrees. Figure 10: The back and front view of Prototype 2. Figure 9: Segmented grips of Prototype 2. Figure 14 shows the curve shape of the slider cover in Prototype 3. In order to improve the shape of the slider cover so that it fits the ear's shape while not worsening the durability, the curve shape of the slider cover is made based on the TRIZ contradiction matrix--Curvature. During phone conversations, when the user's ear is in contact with the slider cover, a curve-shaped slider cover fits the shape of the ears and increases the user's comfort during phone conversations. Figure 15 presents the phone case design made as an intermediary. In order to improve the adaptability of Prototype 3 while keeping the distance between the human body and the phone, a phone case design is made as an intermediary based on the TRIZ contradiction matrix--Intermediary. It helps to isolate the phone from the human body and adapt to different uses, such as placing the phone in a trouser pocket or for general use. Figure 16 shows the hollow design of Prototype 3. In order to increase the distance between the phone and the human body without increasing the weight too much, a hollow design is made based on the TRIZ contradiction matrix--Taking out. Using a hollow design removes unnecessary material and increases the volume of Prototype 3 without increasing the weight. In order to improve the strength of Prototype 3 without increasing the weight too much, a high in-fill rate and hard plastic material are used based on the TRIZ contradiction matrix--Preliminary action. Using a high in-fill rate during 3D printing and using PLA as a hard plastic material improves the strength of Prototype 3 so that it will not break easily. Figure 17 presents the bottom grips removed in Prototype 3. To increase the stress to grip the phone firmly while not affecting user-friendliness when holding or using the phone, the bottom grips are removed based on the TRIZ contradiction matrix--Taking out. Since grips protrude from the phone's edges, and users usually hold the bottom part of the phone, removing the bottom grips can increase the user-friendliness of holding the phone. Figure 16: Hollow design of Prototype 3. Figure 13: Small holes are added in Prototype 3. Figure 15: The phone case design made as an intermediary. Figure 18 shows the curved handle made in Prototype 3.