Lobster eyes with mirror optics

The eye of a lobster focuses reflected light onto the retina using a perfect geometric configuration of square tubes. The human eye works with refraction, bending of light by a lens. The interesting part in this is to take this system and product of nature and place it into architecture, play around with it, until it is possible to learn something new from it. The optic system of the eye of certain lobsters developed in a way, that they don’t need a bent lens, to change the direction of light in order for them to see, instead they use spherical square tubes, with mirrored surfaces. The question is how can we mimic this system in architecture in a sustainable manner.

“I think the biggest innovations of the 21st century will be at the intersection of biology and technology. Steve Jobs

Steve Jobs frequently mentions two values that are very important. First to focus on promising technologies, and second that technology alone is not enough, and we need to combine it with liberal arts.

(…)technology married with the liberal arts that “makes our hearts sing.” Steve Jobs

Biological precedent

Scientific Name: Decapoda

Common Names: crayfish, crabs, lobsters, prawns, and shrimp

Habitat: almost all warm seas

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The Decapoda or decapods (literally “ten-footed”) are an order of crustaceans within the class Malacostraca, including many familiar groups, such as crayfish, crabs, lobsters, prawns, and shrimp.

This species inhabits coral and rocky reefs and is generally found in deeper areas on the outer reef . It is found at depths from shallow subtidal to about 100 m (Davie 2002). It is nocturnal and hides in rock cavities and crevices during the day .

These cave dwellers emerge at night to hunt other crustaceans, sea cucumbers, and starfish. They’re also scavengers, serving their community by keeping reefs clean.

Spiny lobsters are found in almost all warm seas… Spiny lobsters tend to live in crevices of rocks and coral reefs, only occasionally venturing out at night to seek snails, clams, sea-hares, crabs, or sea urchins to eat.

Architectural Precedent

Traditional Moroccan Architecture

Morocco is in Northern-Africa bordering the Mediterranean and the Atlantic. The country’s diverse geography and the land’s long history of being fought over by many countries are the major reasons why the country has developed distinctive architectural styles.

A riad is a traditional Moroccan house or palace with an interior garden or courtyard. Riads (Moroccan mansions) are common in Marrakesh. Based on the design of the Roman villa, they are characterized by an open central garden courtyard surrounded by high walls. This construction provided the occupants with privacy and lowered the temperature within the building.

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Traditional Riad

In the medina solar radiation into the streets are minimised because of how narrow and winding they are.

Streets are very narrow, the main streets are perhaps 3 m, while the smallest are not even 1 meter. This makes the streets of the medina almost always shaded, the sun only reaches the streets when it’s at its highest at midday. There are a few small squares where there are trees and plants, but otherwise there are very few in the public areas and streets. The buildings in Medina Qdima are often 3-4 stories high and there are almost no variations in building height.

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Buildings in the Medina

 COMPLEX STRUCTURES FOCUS REFLECTED LIGHT

Before getting into how the Decapodas eyes work, we need to take a look into how human eyes work.

Human eyes.

 

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Eye optics

First, light enters our eye, and is refracted, or bent, by the cornea, the outermost part of our eye. Refracted light is directed right at the pupil, a small hole in the center of the Iris, the colored part of the eye. The iris can change the size of the pupil to allow more or less light to enter. Light that goes through the pupil is then redirected again by the eyes’s lens, which points the light at nerve cells at the back of the eye. All this information is sent to the brain by nerve cells through the optic nerve.

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Reflection and refraction

Decapod eyes: Eyes with mirror optics

The eye of a lobster focuses reflected light onto the retina using a perfect geometric configuration of square tubes

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Lobster eye on micro-nano scale

The most outstanding characteristic of the lobster eye is its surface, which is composed of numerous squares…these squares are positioned most precisely.

“Even more intriguing is that the sides of each one of these square tubes are like mirrors that reflect the incoming light. This reflected light is focused onto the retina flawlessly. The sides of the tubes inside the eye are lodged at such perfect angles that they all focus onto a single point.

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reflecting system

Rays from an object point entering through different facets are superimposed not by refracting systems as in other superposition eyes, but by a radial arrangement of orthogonal reflecting planes which are formed by the sides of the crystalline cones and the purine layers surrounding them.

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the mirror boxes of a lobster eye

The mirror boxes must be the right depth, two to three times the width, so that most rays are reflected from two of the faces, but not more. Rays that pass straight through are intercepted by the unsilvered ‘tail’ of the mirror boxes, and Vogt (1980) showed that its refractive index decreases in such a way that appropriate critical angle reflexion continues to occur through the clear zone.

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geometry of the square tubes

The optics consists of a grid of micro channels each with a square cross-section. The entrance apertures of the channels are situated on a spherical surface and the individual channels point towards the centre of the sphere. Technically this type of optics is often realized by bending a micro channel plate in two directions. Light hitting the smooth side walls of the channels is reflected towards a focal point. The focal points are located on a sphere with roughly half the radius of the aperture sphere . The exact position depends on the geometry of the channels and on the distance of the light source.

This optics provides a very large angle of field, theoretically it could image light from nearly any direction.

Conclusions and discovery

My inspiration from nature approaches to lessen the human problem, which is not sufficient daylighting in the vast majority of buildings in Morocco. My idea is to seek a sustainable solution to a problem that effects humans, by using nature’s products and systems, that are well adapted to their surroundings and over the long haul, they are working well. In this case the system and product is the decapod crustaceans eyes.

In the modern towns with high-rise buildings, huge glass facades and wide streets in Morocco, the problem is the opposite, the streets let too much light in, as well as the glass surfaces. In the end in these areas, these previously mentioned problems are solved by using electricity for air conditioning, almost all year for cooling. My idea is to keep the ventilation natural as much as possible, which means sunlight can not be more intense than it is already in the interior spaces.

In Morocco there are huge differences between urban and rural living, the urban can be similar to European standards, but the rural can be similar to Africa’s poorer countries.

The northern parts of Morocco have a temperate, Mediterranean climate while the inner- and south parts of the country have a dry and semi arid climate. In the inland and the south parts of the country desert winds can give temperatures between 35-40˚C. In the north average temperature in January are 12˚C and in August 23˚C and in the inland it is 10˚C and 28˚C. In the mountains the temperatures may vary considerably, the winter temperature can go as low as -20˚C and during the summer the temperature can go up to 40˚C.

The opening in the roof lets in light and air, and in dry and hot climate, the opening is important because it modifies the indoor climate and contributes to natural ventilation. It also serves as protection from sun and wind, because the walls are quite high the sun’s rays doesn’t reach the courtyard until the afternoon and then the warm air rises, and convention is created which ventilates the rooms.

However this arrangement doesn’t let enough light into the rooms. From the top floors to the bottom floors, there is less and less light, since there are no openings on the external walls, only facing the courtyards. Even if there is some light on the bottom floors, it will not be spread out in the room but it will only be some light near the walls facing the courtyard.

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Traditional lighting vs. with the device

So what if we could redirect the light that would naturally enter the space, and focus it in a way that ambient light is created, creating more healthy and balanced daylighting? Using the system of the decapod eyes, it could be possible to create a tool that can direct light to areas that need more or to change the lighting of a space.

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Standard lighting techniques

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Existing lighting versus lighting with mirror optics

 

This device could be used in several areas, first of all, using the same amount of light, but redirecting it to design better lighting in spaces in general. In many cases the depths of spaces are too deep, to have a balanced lighting inside, this system could be a tool to simply direct light to the dark areas, instead of using a normal window, in addition, above the window or as part of it, this block could be added as an extra element. The light directing block could even be imagined as bricks, being part of a wall. The devices’ geometry needs further studying and help from a specialist in optics as well as daylighting simulations to test and explore the options and possibilities it can generate in architecture. I think it could be beneficial to use it in existing buildings, with poor lighting, with the use of sustainable materials and fabrication methods and also in new buildings as a tool that redirects light, exactly where it is designed to. Since it would not mean there is more light coming in, it would not change the solar radiation and the heat that goes in, however, on a street, if it is placed on a roof balustrade and would direct the sunlight on the street, it would in fact change the solar radiation, but it could be controlled on what scale would it do so. It could be a combination of technologies, using this square grid to let in air and light, linking ventilation and lighting together. It could be the structural grid of a wall, leaving some squares open and breathing or it could be adapted into the wall as blocks or bricks, but separated and or it could be a panel that can be placed into walls like windows in general or as railings to direct light from the top of buildings. It is important to note, that the intention is always to avoid heat and to use more electricity and to keep the system naturally working, with the help of design and technology.

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Redirection based on the focal point placement

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Redirection of light to create ambient light

 

 

REFERENCES:

 

sahara-nature.com

Flora_of_Morocco

ask nature

marinelifephotography.com

Lobster eye illustration

Marrakesh Palaces and Riads

decapod crustaceans optics

x-ray-optics.de

Moroccan_Architecture traditional and modern

asknature.org strategy 

Human_eye

iucnredlist.org

lobster-love

Spiny lobster

 

 

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