Patent ID: 6838038

Claim:
A laser ablation method for patterning a thin film phosphor layer of a thick film dielectric electroluminescent display having other layers, the method comprising: selecting a wavelength of laser radiation, a laser pulse length, a laser energy density and a sufficient number of laser pulses to pattern the thin film phosphor layer without substantial ablation of or damage to other layers, whereby the wavelength of laser radiation is such that the laser radiation is substantially absorbed by the thin film phosphor layer with minimal absorption by other layers, the laser pulse length is sufficiently short that during the duration of the laser pulse there is minimal heat flow from the thin film phosphor layer to other layers, and the laser energy density and the sufficient number of laser pulses is sufficiently high that energy is deposited in the thin film phosphor layer, whereby at least a portion of the thin film phosphor layer is ablated, and wherein the thin film phosphor layer comprises a material having an electronic band gap and the laser wavelength is less than or equal to the wavelength that corresponds to the electronic band gap.