Plans for commercialization
While SEPIA has many applications, its suitability for large-area digital information display is readily apparent.  In particular, its use as a digital billboard offers many advantages over other large-area display technologies, particularly light emitting diodes (LEDs), for the following reasons:

1.  Cost. LED digital signs are very expensive (often >$250k for a 14' x 48' display), making it onerous to invest in digital advertising.  By virtue of the materials used, SEPIA is expected to cost significantly less.

2.  Regulations.  LEDs and other emissive displays generate significant amounts of light, causing problems for those situated nearby.  Specific zoning regulations prohibit large signs for light pollution and other aesthetic concerns.  Would you want to live right next to a LED billboard?  I didn't think so.  SEPIA is reflective, and would only be lit at night, similar to how printed billboards are illuminated, therefore providing a much less obtrusive alternative to LEDs, with all the beneficial features of a digital sign.

3.  Color saturation.  Although direct comparisons between reflective (SEPIA) and emissive (LED) displays can be difficult because of their operating principles, SEPIA can be compared to other reflective displays such as the E-Ink Triton display.  Triton displays use laterally arranged red, green, blue, and white sub-pixels - when red needs to be shown, the green, blue, and white sub-pixels are turned off, meaning only 1/4 of the display area is actually being used to generate red.  SEPIA uses every square inch to generate every color through its unique stacked geometry, yielding a theoretical 100% color saturation, making blues bluer, reds redder, etc.

4.  Weight. LED billboards can weight over 6000 lbs (for 14' x 48' bulletin signs), requiring tens of thousands of dollars in retrofitting costs in order to reinforce existing printed billboard structures.  The use of lightweight materials allows SEPIA to be constructed for approximately 1/5th of the weight per area, allowing for lower transportation and installation costs.  Additionally, SEPIA may be used as a rapidly deployable digital display for disaster relief because of its ability to be stored and transported easily.

5.  Energy use.  Although LEDs are generally considered to be energy efficient in generating light, digital displays actually consume an enormous amount of energy, up to approximately 30 times that of an average US home.  This is for two reasons: (1) there are a very large number of LEDs being operated at once and (2) LEDs need to be cooled in order to achieve their stated efficiency and lifetime, often achieved through energy intensive active cooling.  SEPIA's operating principle allows it to use approximately 50x less energy per area than LED digital signage.  SEPIA has the potential to be powered completely by solar panels located on or near the display.

6.  Competiton with ambient light.  All display technologies that generate light inherently compete with the light that exists around you for attention within your eye - too much ambient light and the light coming from your display gets washed out.  This is why reflective technologies, such as eletrophoretic displays (e.g. the Amazon Kindle), are much easier to read in direct sunlight.  In the context of digital billboards, reflective displays have an advantage over emissive displays because in the US, most vehicular travel (~60-70%) takes place during daylight hours.  While it is true that emissive displays give greater contrast at night, more impressions will be made on travelers during the day.  SEPIA's reflective nature is therefore advantageous relative to LED and other emissive technologies.

7.  Operation in extreme environments.  Through careful selection of materials, SEPIA is expected to be operable in a wide range of temperatures and exposure conditions without active cooling or heating, making it appropriate for outdoor use.

8.  Mechanical flexibility.  The flexible nature of SEPIA may allow it to be used for unique billboard or other displays that require conformal coating of complex geometries.




SEPIA Displays is a startup venture emerging from Harvard University, seeking to apply a radical new approach to large-area digital display hardware.  Please inquire about opportunities for partnership and manufacturing.

Figure 1.  Illustration of SEPIA monochromatic operational principle.  At rest in (a), the observer views colored ink on the support surface indicating a pixel 'ON' state as seen at right from the observer's view.  Applying voltage to the artificial muscle in (b) causes membrane relaxation, a shift of mass away from the observer, and a consequent flow of ink out of the observer's view into the channel/reservoir.  This 'OFF' state is perceived by the viewer as a small colored 'dot' as the ink's disappearance from view reveals the opaque white support underneath.
Figure 2.  Illustration of the full color version of a SEPIA pixel.  Using cyan, magenta, and yellow ink 'pockets', laterally arranged in a triangular pattern, full color mixing can be achieved through selective absorption of incident light.  Without applied voltage in (a), the pixel appears black as the combination of CMY inks in the 'composite' area absorb most of the incident light.  In (b), voltage applied to the artificial muscle connected to the yellow ink reservoir removes yellow ink from the 'composite' area, causing the pixel to appear blue.
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Above: Cuttlefish are the inspiration for the SEPIA display concept.


As cephalopods are considered one of the greatest camouflage artists in nature, we decided to emulate their abilities synthetically.  After some preliminary success in the lab, we started to identify a significant market opportunity for large-area digital signage through providing a low-cost, full-color, reflective technology.  Please read below to learn about the SEPIA display technology and plans for commercialization.  If you would like to learn more, please contact me.


In the laboratory, we use artificial muscles (dielectric elastomers) to replicate the cephalopod muscles in order to drive the display.  The essential operating principle revolves around making a small colored region reversibly grow  many times its original size in order to become appreciably visible.  This is accomplished synthetically using two actions:

1.  Using artificial muscles to act as a fluidic pump, allowing reversible and voltage tunable actuation.

2.  Reversibly forcing colored fluid through a perforation in an opaque surface to create reflective contrast on the device surface.

The basic SEPIA monochromatic pixel design is illustrated below:
Above: This video illustrates four, 9 mm diameter artificial chromatophore pixels being driven by dielectric elastomers behind the white support (not seen) in real time.  The speed of actuation is on the order of 10's of ms, which is fast enough to generate video refresh rate images.  This proof of concept device is unoptimized in terms of color saturation, operating voltage, and lifetime.
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SEPIA display concept
SEPIA (Soft Electroactive Polymer Ink Array) is a reflective display concept developed in collaboration with Samuel Shian to reproduce the operating principle observed in cuttlefish and other cephalopods used to change their skin coloration.  A brief introduction to cuttlefish camouflage abilities can be seen here.  Chromatophores are pigmented cells that are soft and spherical in geometry that are surrounded by muscle fibers in the animal's skin.  When these muscles contract, the chromatophores are deformed from a sphere into a disc shape, approximately 10-15x their original diameter.  Each chromatophore acts like a single pixel in a TV screen in that it displays a certain color or not: when small and spherical, it is difficult to see (the pixel is 'off'), but when expanded in area, the coloration is readily visible to an observer (the pixel is 'on').  Many chromatophores distributed both laterally over the skin's area as well as through the skin's thickness, with many different colorations, provides a large palette of color with which to disguise itself.
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RECENT UPDATES:
4/30/15
Sepia Displays has recently completed a full-color pixel demonstration!  Please inquire by email to get a preview of just how vivid it is!

11/4/14
Sepia Displays has been selected as one of the top 30% of applications across the whole of Harvard to receive funding through the Office of Sustainability!

9/30/14
It is a pleasure to report that Sepia Displays has been chosen to give a demonstration at the iMatSci event hosted by the Materials Research Society (MRS)! Look for the cephalopod-inspired prototype module December 1st, 2014 at Hynes Convention Center where emerging materials science-related concepts with commercial promise interface with the industrial and investor communities.  Attending the iMatSci event is free, and does not require registration at the MRS Fall Meeting.

9/9/14
Sepia Displays is honored to be selected as part of the Fall 2014 Venture Incubation Program (VIP) cohort within the i-Lab at Harvard!  I am excited to interact with such energetic and entreprenurial people as the business model for Sepia Displays is honed further.

5/21/14
Sepia Displays is proud to announce our selection as a 2014 TechConnect National Innovation Awardee!  The TechConnect National Innovation Awards selects the top early-stage innovations from around the world through an industry-review process of the top 20% of annually submitted technologies into the TechConnect National Innovation Summit.  Rankings are based on the potential positive impact the submitted technology will have on a specific industry sector. More details can be found here.
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