Abstract: Provided is an optical imaging system, adapted for presenting an image of a particle. The optical imaging system includes a collimated light source, a flow channel, and a telecentric lens. The collimated light source is adapted for emitting a parallel beam. The flow channel is arranged on the transmission path of the parallel beam and is adapted for allowing the particle to pass through. The telecentric lens is arranged on the transmission path of the parallel beam. The parallel beam passes through the flow channel before transmitted to the telecentric lens, and the telecentric lens is adapted for converging the parallel beam onto an imaging plane.

Abstract: A coin battery testing device, including a bottom base, an upper cover, a positive conducting structure, and a negative conducting structure, is provided. The bottom base has an observation region and is adapted to carry a coin battery by the observation region. The upper cover is detachably connected to the bottom base and adapted to cover the coin battery on the observation region. The upper cover has an opening and the opening corresponds to the observation region, such that the coin battery is adapted to be observed through the opening. The positive conducting structure is disposed on the bottom base and adapted to be connected to a positive electrode of the coin battery on the observation region. The negative conducting structure is disposed on the bottom base and adapted to be connected to a negative electrode of the coin battery on the observation region.