fig4

Figure 4. Tactile sensor arrays. (A) Image of an 8 × 8 transparent capacitive sensor array on the palm and the capacitance changes when the finger approaches at 15 and 5 mm. Reproduced with permission from Ref.^[84]. Copyright^© 2017. American Chemical Society. (B) Pressure mapping on a 4 × 4 pressure sensor array by placing acrylic boards of “P”, “K”, and “U”. Reproduced with permission from Ref.^[85]. Copyright^© 2019. American Chemical Society. (C) (a-c) Images of a 5 × 5 tactile sensor array. (d-f) The current mapping ability under the pressure of a key. Reproduced with permission from Ref.^[86]. Copyright^© 2014. Springer Nature. (D) Images of a 4 × 4 tactile sensor array and a highly flexible ability. Reproduced with permission from Ref.^[87]. Copyright^© 2020. OAE Publishing Inc.