Image display device

#The invention relates to an image display device comprising a light modulation panel, an illumination device facing the light modulation panel and a light source coupled to the illumination device, said illumination device comprising at least one separating layer which has at least one flat surface extending parallel to the light modulation panel and a serrated surface situated on a side remote from the flat surface, said serrated surface having a plurality of sawtooth-shaped, juxtaposed projections which are each bounded by a first and a second separating surface.

#An image display device of this type is used in, for example, head-mounted displays (HMDs) and projection televisions. LCDs which are either transmissive or reflective are regularly used as light modulation panels. In a reflective LCD, the LCD is illuminated from the same side as the side from which it is viewed. In transmissive LCDs, the LCD is illuminated from a different side than that from which it is viewed. Notably for HMDs, the light source and the associated illumination device should be as thin as possible so that the HMD can be given a relatively compact form. Reflective LCDs are preferably used in HMDs. If the illumination device is relatively thin, it has the additional advantage that a lens situated on a side of the illumination device remote from the light modulation panel can be arranged relatively close to the illumination device, which is favorable for achieving an optimal magnification.

#In such an image display device known from European patent application EP-A1-0 948 755, the illumination device comprises two layers connected to each other by means of a serrated surface. One layer has a single refractive index and the other layer has two refractive indices, one of which corresponds to the refractive index of the first layer. The first and second separating surfaces of the serrated projections both enclose acute interior angles with the flat surface of the separating layer.

#In the drawings:

#FIG. 1 shows a first embodiment of an image display device according to the invention,

#FIG. 2 is an enlarged part II of the image display device shown in FIG. 1,

#In the Figures, corresponding components are denoted by the same reference numerals.

#FIG. 1 shows an image display device 1 according to the invention, comprising a light modulation panel 2 such as, for example, an LCD.

#The image display device 1 is further provided with an intermediate layer 3 connected to the light modulation panel 2, a separating layer 4 connected to the intermediate layer 3 and a light-conducting layer 5 connected to the separating layer 4. An end face 6 of the conducting layer 5 is provided with a diffusion layer 7. The image display device further comprises a light source 8 situated on a side of the diffusion layer 7 remote from the light-conducting layer 5. The light source 8 is, for example, a light-emitting diode (LED) which emits light of a desired color such as, for example, white, red, green or blue. Coupling-in light in a light-conducting layer 5 in such a way is known per se and will therefore not be further explained.