NEW: Bring Me Sunshine - the evolution of sunlight readability

A brand new optical bonding technique already commissioned by automotive industry top marques is the subject of much quiet excitement in downtown Huntingdon, home to UK digital display and computing technology specialist, Display Solutions. Martin Whitehead is System's Manager at the company and has been working closely with Taiwanese tech start-up CiVue on a solution that he feels is a genuine advance in sunlight readable technology.

“What I find particularly advantageous with this new process,” says Whitehead, “is that all the problems previously associated with optical bonding have been eliminated. That is to say there is no cracking, yellowing or bubbling with this. The new process and material offers a system of achieving sunlight readable displays which takes technology into a whole new realm.

“The key to the new material’s flexibility and strength,” Whitehead continues, “lies to a large extent in its application as a liquid as opposed to the traditional film that would be applied directly to a screen with older optical bonding methods. While much of the process remains commercially under wraps, we can reveal that built-in UV and IR filters give the CiVue product resistance against atmospheric deterioration and it remains compliant providing far superior impact absorption - ideal for the knocks and bumps of daily public use.”

As part of an independent customer evaluation, a complete unit with the new bonding was subjected to an intense 1000 hour test in a Q-Sun tank where it was bombarded with UV light and high humidity, equal to ten years usage in the worst conditions found on earth. The CiVue unit emerged with no visible signs of deterioration whereas a current market leading product failed in half the time, after 500hr, with yellowing, bubbling and discolouration.

“This is significant,” says Whitehead, “as it means that optical bonding can now be used in the harshest of conditions, limited only by the parameters of LCD operating temperatures. In effect, while the new bonding can function from -40~+85oC, the LCD will limit that to -20~+60oC but there is no doubt that this offers a far more rugged solution than previously available.”

Whitehead continues: “While it’s ideal on its own in direct sunlight, together with existing transflective technologies it forms the perfect solution in variable light, for example for ATM’s. As an engineer it really increases options. For example, for outdoor point of information units it presents exactly the right level of ruggedness combined with sunlight readability. Furthermore, it offers significant cost saving opportunities on both energy consumption and maintenance fronts. Previously, if the front surface was damaged it was necessary to replace the entire unit. Now, the front glass can be stripped, replaced and rebonded for a fraction of the cost, and the undamaged components re-used. This option scores a huge amount of green points, which is becoming a design-in essential for many projects.”

Sunlight Readable Technologies - The story so far:
By Martin Whitehead of Display Solutions

   First up is the rather agricultural high brightness transmissive solution. This basically cranks up backlighting by simply adding more lights. More lights mean you are not only using more energy but also producing more heat which must be dissipated. There is a higher running cost with the transmissive route but also shorter component life, frequent servicing and a much bulkier product is required to house the large number of backlights.

   The second approach is the Reflective route using the natural light source, with ambient light being reflected back through the LCD. This is very effective for mono displays but not for colour LCDs. While this method scored huge green points in its low energy consumption, it performs poorly when there is little natural light and is rendered unreadable at night without backlights.

   The Transflective approach is a combination of the first two and very efficient in many ways. By combining reflected light and a backlight, it is able to be read across a wide range of ambient light while keeping energy consumption down. This provides an effective sunlight readable solutions but never reaches its full potential.

   All outside displays have to use a protective front sheet of either glass or plastic. This reduces the sunlight readability due to internal refelections reducing the contrast ratio. At each air/glass boundary the light disperses in every direction. That is in and out which in turn leads to reduced contrast and energy efficiency.
   Typically around 13% of the inbound sunlight and outbound backlight will be lost and scattered. Optical Bonding eliminates the air gap and hence the air/glass boundaries. When combined with an anti-reflective coating on the outside surface, total reflections can be reduced to 0.5%. This means that a normal brightness, transmissive display with optical bonding alone is now good enough for 80% of the sunlight readable solutions.
   Alternatively, when combined with transflective displays it produces a truly outstanding result!

See our Sunlight Readable product range or call 01480 411600 for more information