To make an element visible in the dark, it is known to use luminescent compounds that are charged with light energy before releasing it. Documents EP 2 264 554, EP 2 717 104 and EP 1 837 387 that describe the use of phosphorescent and/or fluorescent compounds can be cited as examples in the watchmaking industry. These can be hands or external elements such as the dial, the bezel, the base or the middle part, which are charged with luminescent particles or covered with a luminescent material. In a variant, the luminescent source can be provided in chip form positioned at different locations in or on the watch case.
To the applicant's knowledge there is no document in the prior art that proposes to use the watch glass gasket, which is arranged between the middle part and the glass and intended to ensure that the watch case is sealed from the outside and, if necessary, to ensure that the glass is fastened to the middle part, as a luminescent source. Hitherto, the tendency has been to the middle part, as a luminescent source. Hitherto, the tendency has been more to keep the watch glass gasket as discrete as possible so as not to spoil the aesthetic appearance and impair the design of the watch.