an improvement in a light therapy device including multiple light - emitting diodes positioned in a handheld portable device is disclosed . where the housing and the leds are configured to have direct contact with the skin or tissue of the user without any intermediary materials , and light the surface and underlying layers of tissue for photodynamic stimulation of the cells . two iterations of the device utilize light known to have a bactericidal effect in the case or acne or rosacea . the devices are fabricated from an injection molded plastic housing . the housing contains an arrangement of 36 - 72 leds on a circuit board in an arrangement to provide even lighting over the skin or tissue surface .