Responsive transparent displays that don't need an internal light source and can be easily integrated on windows and glasses can be made using the optical features embedded in marine shells.
The scientists at MIT and Havard have identified two optical structures within the limpet's( it is an aquatic snail with a shell broadly conical in shape) shell that give its blue stripped appearance.The structures are configured to reflect blue light while absorbing all other wavelengths of incoming light.The findings in the journal Nature Communications, represent the first evidence of an organism using mineralised structural components to produce optical displays.While birds, butterflies, and beetles can display brilliant blues, among other colours, they do so with organic structures, such as feathers, scales, and plates.The limpet by contrast produces its blue stripes through an interplay of inorganic, mineral structures, arranged in such a way as to reflect only blue light.They sat such optical structures may serve as a design guide for engineering colour-selective, controllable, transparent displays that require no internal light source and could be incorporated into windows and glasses.
"Lets imagine a window surface in a car where you obviously want to see the outside world as you're driving, but where you also can overlay the real world with an augmented reality that could involve projecting a map and other useful information on the world that exists on the other side of the windshield," says co-author Mathias Kolle. "We believe that the limpet's approach to displaying colour patterns in a translucent shell could serve as a starting point for developing such displays."
Kolle, whose research is focused on engineering bioinspired, optical materials including colour changing, deformable fibres started looking into the optical features of the limpet when his brother Stefan, a marine biologist now working at Havard, brought Kolle a few of the organisms in a small container.Stefan Kolle was struck by the mollusc's brilliant patterning, and recruited his brother, along with several others, to go deeper into the shell's optical properties.
To do this, they performed a detailed structural and optical analysis of the limpet shells.They observed that the blue stripes first appear in the juveniles, resembling dashed lines.The stripes grow more continuous as a limpets matures, and their shade varies from from individual to individual, ranging from deep blue to turquoise.
The researchers scanned the surface of a limpet's shell using scanning electron microscopy, and found no structural differences in areas with and without the stripes-an observation that led them to think that perhaps the stripes arose from features embedded deeper in the shell.To get a picture of what lay beneath, the researchers used a combination of high-rsolution 2-D and 3-D structural analysis to reveal the 3-D nanoarchitecture of the limpet's translucent shells.
What they found was revealing: In the regions with blue stripes, the shell's top and bottom layers were relatively uniform, with dense stacks of calcium carbonate platelets and thin organic layers, similar to the shell structure of other molluscs.However, about 30 microns beneath the shell surface the researchers noted a stark difference.In these regions, the researchers found that the regular plates of calcium carbonate morphed into two distinct structural features: a multilayered structure with regular spacing between calcium carbonate layers resembling a zig-zag pattern and beneath this layer of randomly dispersed, spherical particles.
The researchers measured the dimensions of the zigzagging plates, and found the spacing between them was much wider than the more uniform plates running through the shell's unstripped sections,They then examined the potential roles of both the multilayer zigzagging structure and the spherical particles.They used optical microscopy, spectroscopy, and diffraction microscopy to quantify the blue stripe's light-reflection properties. They then measured the zigzagging structures and their angle with respect to the shell surface, and determined that this structure is optimised to reflect blue and green light,The researchers also determined that the disordered arrangement of spherical particles beneath the zigzag structures serves to absorb transmitted light that otherwise could de-saturate the reflected clue colour.
From these results, Kolle and his team deduced that the zigzag pattern acts as a filter, reflecting only blue light. As the rest of the incoming light passes through the shell, the underlying particles absorb this light-an effect that makes shell's stripes appear even more brilliantly blue.
Related posts: 3-D displays without glasses
Source: Mumbai Mirror
The scientists at MIT and Havard have identified two optical structures within the limpet's( it is an aquatic snail with a shell broadly conical in shape) shell that give its blue stripped appearance.The structures are configured to reflect blue light while absorbing all other wavelengths of incoming light.The findings in the journal Nature Communications, represent the first evidence of an organism using mineralised structural components to produce optical displays.While birds, butterflies, and beetles can display brilliant blues, among other colours, they do so with organic structures, such as feathers, scales, and plates.The limpet by contrast produces its blue stripes through an interplay of inorganic, mineral structures, arranged in such a way as to reflect only blue light.They sat such optical structures may serve as a design guide for engineering colour-selective, controllable, transparent displays that require no internal light source and could be incorporated into windows and glasses."Lets imagine a window surface in a car where you obviously want to see the outside world as you're driving, but where you also can overlay the real world with an augmented reality that could involve projecting a map and other useful information on the world that exists on the other side of the windshield," says co-author Mathias Kolle. "We believe that the limpet's approach to displaying colour patterns in a translucent shell could serve as a starting point for developing such displays."
Kolle, whose research is focused on engineering bioinspired, optical materials including colour changing, deformable fibres started looking into the optical features of the limpet when his brother Stefan, a marine biologist now working at Havard, brought Kolle a few of the organisms in a small container.Stefan Kolle was struck by the mollusc's brilliant patterning, and recruited his brother, along with several others, to go deeper into the shell's optical properties.
To do this, they performed a detailed structural and optical analysis of the limpet shells.They observed that the blue stripes first appear in the juveniles, resembling dashed lines.The stripes grow more continuous as a limpets matures, and their shade varies from from individual to individual, ranging from deep blue to turquoise.
The researchers scanned the surface of a limpet's shell using scanning electron microscopy, and found no structural differences in areas with and without the stripes-an observation that led them to think that perhaps the stripes arose from features embedded deeper in the shell.To get a picture of what lay beneath, the researchers used a combination of high-rsolution 2-D and 3-D structural analysis to reveal the 3-D nanoarchitecture of the limpet's translucent shells.
What they found was revealing: In the regions with blue stripes, the shell's top and bottom layers were relatively uniform, with dense stacks of calcium carbonate platelets and thin organic layers, similar to the shell structure of other molluscs.However, about 30 microns beneath the shell surface the researchers noted a stark difference.In these regions, the researchers found that the regular plates of calcium carbonate morphed into two distinct structural features: a multilayered structure with regular spacing between calcium carbonate layers resembling a zig-zag pattern and beneath this layer of randomly dispersed, spherical particles.
The researchers measured the dimensions of the zigzagging plates, and found the spacing between them was much wider than the more uniform plates running through the shell's unstripped sections,They then examined the potential roles of both the multilayer zigzagging structure and the spherical particles.They used optical microscopy, spectroscopy, and diffraction microscopy to quantify the blue stripe's light-reflection properties. They then measured the zigzagging structures and their angle with respect to the shell surface, and determined that this structure is optimised to reflect blue and green light,The researchers also determined that the disordered arrangement of spherical particles beneath the zigzag structures serves to absorb transmitted light that otherwise could de-saturate the reflected clue colour.
From these results, Kolle and his team deduced that the zigzag pattern acts as a filter, reflecting only blue light. As the rest of the incoming light passes through the shell, the underlying particles absorb this light-an effect that makes shell's stripes appear even more brilliantly blue.
Related posts: 3-D displays without glasses
Source: Mumbai Mirror
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