Patent ID: 7246932

Claim:
A data display device including: a light-guide element made of an optically transparent material having at least two polished surfaces faced to one another, whereby at least one surface contains at least one gravure forming a diffuse-reflective character, and a light source arranged to illuminate said character wherein the device also includes: at least one additional light-guide element made of an optically transparent material having at least two polished surfaces faced to one another, whereby at least one surface contains at least one additional gravure forming an additional diffuse-reflective character, and at least one additional light source arranged to illuminate said additional diffuse-reflective character, wherein the at least one gravure and the at least one additional gravure form in aggregate an information unit; whereby said light-guide elements being mounted at a distance one from each another such that the minimum distance between the guide-elements exceeds the red-light wavelength and each light source is being optically isolated from each another, and wherein said light-guide elements are arranged to allow only an air gap to exist therebetween, and wherein one of the surfaces of one of the light-guide elements is roughened through a grinding process and a transparent film is fixed on the surface which is opposite to the roughened surface, such that the transparent film is arranged between at least two light-guide elements.