Spatial light modulator featured with an anti-reflective structure
View Patent ↗A spatial light modulator supported on a device substrate includes a plurality of light modulation elements to modulate a light emitted from a light source. The spatial light modulator and the device substrate further comprises a cyclic structure on a surface of the spatial light modulator and/or the device substrate for preventing a reflection of the incident light from the cyclic structure. In an exemplary embodiment the cyclic structure includes cyclic structural elements having a distance between two cyclic elements shorter than the wavelength of an incident light for preventing a reflection of the incident light from the cyclic structure.
1. An image projection system comprising:
a spatial light modulator supported on a device substrate for controlling a light modulation element further including a hinge disposed on said device substrate to support a mirror at a distance above said device substrate to reflect and modulate an incident light emitted from a light source;
an antireflection structure comprising cyclic protrusions extended from a surface of said device substrate underneath said light modulating element wherein a distance between two of said cyclic protrusions is shorter than a wavelength of an incident light for preventing a reflection of said incident light from said antireflection structure;
said cyclic protrusions having a cross sectional shape of substantially side-by-side vertical triangles; and
said side-by-side triangles is characterized by:
λ> P>λ/ 2, and
H/W> 3, where
the P is a pitch between top vertex points of the side-by-side triangles, the λ is the wavelength of the incident light, the H is the height of the side-by-side triangles, and the W is a base width of the side-by-side triangles.
2. The image projection system according to claim 1 wherein:
said antireflection structure is disposed on a backside of said mirror for preventing a reflection of light from said backside of said mirror.
3. The image projection system according to claim 1 wherein:
said antireflection structure is disposed on a top surface of said device substrate underneath a gap between two adjacent mirrors.
4. The image projection system according to claim 1 , comprising:
the antireflection structure is disposed on a top surface of the device substrate adjacent to said hinge underneath said mirror.
5. The image projection system according to claim 1 , wherein:
the spatial light modulator further comprising a plurality of light modulation elements each having a mirror for reflecting and modulating the incident light wherein said antireflection structure is disposed on a backside surface of the mirror of each of said light modulation elements.
6. An image display apparatus comprising:
a spatial light modulator modulating an incident light emitted from a light source;
a device substrate for supporting said spatial light modulator thereon wherein said device substrate further includes an antireflection structure comprising cyclic protrusions extended from a top surface of said device substrate having a cross sectional shape of substantially side-by-side triangles wherein a distance; and
said side-by-side triangles is characterized by:
λ> P>λ/ 2, and
H/W> 3, where
the P is a pitch between top vertex points of the side-by-side triangles, the λ is the wavelength of the incident light, the H is the height of the side-by-side triangles, and the W is a base width of the side-by-side triangles.
7. The image projection system according to claim 6 wherein:
said spatial light modulator is contained in a package and said antireflection structure is disposed on internal walls of said package for preventing a reflection from said internal walls of said package.
8. The image projection system according to claim 6 , wherein
said spatial light modulator is contained in a package and said antireflection structure is disposed on outer walls of said package for preventing a reflection from said outer walls of said package.
9. The image projection system according to claim 6 , comprising:
the cyclic structure is disposed on a top surface and a bottom surface opposite said top surface of the device substrate.
10. The image display apparatus according to claim 6 , further comprising
a light source for projecting a polarized incident light, and
the antireflection structure is oriented in one direction parallel with a polarization direction of the polarized incident light.
11. The image display apparatus according to claim 6 , further comprising
a light source for projecting a polarized incident light, and
the antireflection structure is oriented in one direction perpendicular to a polarization direction of the polarized incident light.
12. The image projection system according to claim 6 wherein:
said spatial light modulator is contained in a package with a cover member and said antireflection structure is disposed on a surface of said cover member.
13. The image projection system according to claim 6 wherein:
said spatial light modulator is contained in a package with a cover member and said antireflection structure is disposed on an inner surface and an outer surface of said cover member.
14. A method of manufacturing a spatial light modulator for modulating an incident light projected thereon comprising
applying an imprinting method, etching method or sol-gel method for forming an antireflection structure comprising a plurality of cyclic protrusions to having a cross sectional shape of substantially side-by-side triangles extend from a top surface of a device substrate preventing a reflection of said incident light from said antireflection structure; and
said side-by-side triangles is characterized by:
λ> P>λ/ 2, and
H/W> 3, where
the P is a pitch between top vertex points of the side-by-side triangles, the λ is the wavelength of the incident light, the H is the height of the side-by-side triangles, and the W is a base width of the side-by-side triangles.