>13.2mm times 8.8mm is 116.16 square mm or 0.18 square inches. >So they are not talking about area. >Neither about the diagonal that is 15.8644 mm or 0.6246 >inches.
As already mentioned by greenwing, the inch/fractional inch designation of compact camera sensor sizes is the convention used to define the Vidicon Tube.
The convention used the diameter of the outside dimension of the tube, but the actual sensing area was about 2/3rds the size of the diameter of the glass envelope. So 2/3rds of an inch is .66667 or 16.9mm. The diagonal of the sensor referenced by the 1 inch designation in the referenced cameras is about 15.86 mm which is close to the 16.9mm.