Electroflex

August 2011

I. Background

As a fun distraction from my graduate studies, I audited Dr. Joe Patterson's ASTR C3646 Observational Astronomy course during my first year at Columbia University. This class comprised of lectures as well as nighttime stargazing sessions at the Rutherford Observatory atop Pupin Hall.

The Observatory was built in the early 1900s, and the famously big lights of Manhattan have increasingly polluted the night sky since. These days, the majority of the Astronomy Department's celestial observation is conducted off-site, while this Morningside Heights observatory is used primarily for teaching and public outreach. Nevertheless, we were often able to pull off some amazing shots.

After a particularly engaging conversation about astrophotography one day, Professor Patterson offered to lend me his personal collection of film SLR cameras and a large assortment of lenses. I spent the following year wandering around Manhattan on a photo-taking safari.

II. Inspiration

On my way downtown to meet friends one night, I stood on the platform at the 116th Street subway station taking photos. The "clack clack" of the old camera's reflex mirror reverberated through the empty subterranean space. I got some funny looks from my fellow subway riders. Concerned that they were bothered by the noise, I put the camera back in my bag and continued to wait for the 1 train.

That same semester, I was also enrolled in Dr. Andreas Hielscher's BMEN E4894 Biomedical Imaging course. One lecture discussed dichroics and their beam-splitting applications in imaging systems. Beam-splitting with a solid-state material? There could be potential to use this to build a silent SLR camera. But dichroics selectively reflect and transmit certain ranges of visible light, which does not allow for accurate color re-creation.

An internet search on dichroics and related materials led me to electrochromics - materials that change between transparent and opaque depending on the electric charge applied through it. Further research uncovered a special subset of this material - reflective electrochromic glass, which transitions between transparent and reflective states upon electrical stimulation.

Prior art searches found the Canon Pellix, an SLR design that used a semi-transparent "pellicle" mirror; a portion of the light would reflect up into the user's eye, and a portion of the light would fall upon the imaging sensor. If this was considered a viable product, then I was assured that the market would welcome a similar but actively optimized design.

III. Concept

I proposed a new single-lens reflex camera design that uses a stationary piece of reflective electrochromic glass, positioned at an angle directly in the beam path of the light coming into the camera through the lens. When the electrochromic element is in its discharged reflective state, the light would reflect off the surface, travel through the pentaprism, and into the user's eye. Pressing the shutter release would apply an electric charge to the electrochromic element, energizing the material and causing it to become transparent. The light from the lens could then travel through the glass with (theoretically) minimal attenuation onto the imaging sensor for recording. After the prescribed exposure time value has lapsed, the electrical signal would be switched off, and the electrochromic element returned to its resting reflective state.

In essence, this stationary piece of electrochromic glass would replace the moving mirror of a traditional SLR, controlling the incoming light with its variable material properties rather than physical displacement. Advantages of this design over the traditional moving reflex mirror are silent operation, robustness in operation and maintenance due to lack of moving parts, all while providing the user with a true optical viewfinder. Disadvantages of the new design stem from the speed at which the electrochromic element can switch between reflective and transparent states. Furthermore, transparency of the glass can be optimized, but will never achieve the 100% transmissivity of pure air.

I drafted the patent application pro se while applying for my first job, submitting it to the USPTO a few months prior to starting a new job at Stryker Endoscopy.

IV. Electroflex

As I was awaited a response from the Patent Office regarding my application, I turned to two of my other hobbies - branding and logo design. 

Ever since the advent of twin-lens reflex (TLR) cameras and continuing through the mid-century nascence of SLRs, camera manufacturers traditionally have added "-flex" to the end of their name to highlight the "reflex" mirror(s) incorporated within those designs. Examples of such suffixation include Canon's Canonflex, Pentax's Pentaflex, Rollei's Rolleiflex, Ricoh's Ricohflex, the list goes on.

I chose the name "Electroflex" as an homage to these technological progenitors, with emphasis on the Electricity and Electronics that drive the core premise of this modern revision.

The Electroflex logo comprises the letters "E" and "F", stylized to resemble a cutaway view of an SLR camera. The elliptical stem of the "E" represents the front lens element, with its upper and lower bars as the lens barrel. The central bar of the "E" conveys the path of incoming light, reflecting upward and again, then exiting through the viewfinder. The electrochromic element is indicated by the negative space between the two light paths.

In a serendipitous turn, the negative space also resembles the Chinese character 片, which, among other things, can mean "film" or "element". 

V. Patent

Following a mercifully brief exchange of Office Actions with the Patent Examiner, my utility patent was issued in 2011 as United States Patent 8,007,187.

VI. Prototype

I used a portion of my second paycheck to purchase a sample of reflective electrochromic glass from Kent Optronics. A demonstration prototype was constructed using this device in conjunction with laser modules.

VII. Next steps

This project has been an invaluable learning experience thus far, especially in affording me hands-on experience with the patent application process. Work will continue in prototype development, and it is my goal to eventually incorporate this technology in certain SLR product lines - stay tuned.

In the meantime, if you have any feedback or suggestions, please send me an email - I'd love to hear your comments.

VIII. Acknowledgements

My deepest gratitude to Professor Joe Patterson for allowing me to audit his Observational Astronomy course, and for trusting me to take his collection of cameras and lenses throughout the concrete jungle of Manhattan.