Hitachi Chemical Rolls Out Voltage-controlled Dimming Film

Jul 22, 2009 20:09 Chiho Matsuda, Nikkei Monozukuri

Hitachi Chemical Co Ltd commercialized a dimming control film whose shading can be adjusted by changing the applied voltage and began volume production.

The film has already been adopted for applications such as windows of airplanes. And the company expects that it will be used for vehicles, ships and home electric appliances in the future, aiming at sales of ¥5 billion (approx US$53.4 million) in 2012.

The new film consists of two polyethylene terephthalate (PET) films coated with a transparent conductive layer and matrix resin dispersed with microcapsules that contain oriented particles. And the matrix resin is sandwiched by the PET films.

When voltage is not being applied, the particles are not oriented and their color is navy blue, thus shielding light. When alternating voltage is applied to the oriented particles, the particles become oriented and transparent.

The shading can be steplessly adjusted from navy blue to transparency to control the optical transmittance. The power consumption is 1.1W/m².

According to Hitachi Chemical, the market for light control glass is expanding due to the increasing demands to protect privacy, to decorate private space and to prevent room temperature from rising by blocking sunlight.

Existing dimming control technologies include liquid crystal and electrochromic devices. However, with the former, it is difficult to delicately control the color between white and transparency. And the latter has problems of slow response speed and small size.

So, there has been a demand for a product that can be made in large sizes, steplessly adjust light quantity and produce shading deep enough to screen sunlight.

Hitachi Chemical introduced the SPD (suspended particle device) technology from the US and developed a new matrix resin by using its proprietary resin synthesis technology. Furthermore, by utilizing its technologies to apply films, to adjust the size of light-control particle and to evaluate electrical properties, the company succeeded in developing a wide and long dimming control film whose shading can be controlled by changing the applied voltage.

Users can produce light-control glass, light-control plastic plates and so forth by applying the dimming control film to glass, polycarbonate and acrylic plates.

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