Patent ID: 7548251

Claim:
An image forming device comprising a photosensitive recording medium pack and a display panel for exposing the photosensitive recording medium to light, the recording medium pack comprising: a photosensitive recording medium; and a case containing the recording medium and having an exposure opening for exposing the recording medium; the display panel comprising: a light transmissive substrate including a first surface for facing the photosensitive recording medium, a second surface which is opposite from the first surface, and thickness T defined as spacing distance between the first surface and the second surface; a plurality of light emitting elements provided on the second surface to be spaced from each other; wherein the display panel is inserted in the case of the recording medium pack through the exposure opening with the first surface of the light transmissive substrate facing the photosensitive recording medium; a cover attached to the second surface of the substrate for enclosing the plurality of light emitting elements: and a driver unit mounted on the cover for driving the plurality of light emitting elements: wherein, when refractive index of the substrate is expressed by n and minimum spacing distance between the plurality of light emitting elements is expressed by S, the thickness T satisfies an inequality: T ≤ S ⁢ n 2 - 1 2 ; and wherein the display panel directly faces the photosensitive recording medium without any intervening lens.