A brighter picture

Omron Corporation has developed a new manufacturing technique for building liquid crystal display frontlights that promises to make LCDs brighter than ever before.

Omron Corporation has developed a new manufacturing technique for building liquid crystal display (LCD) frontlights that promises to make LCDs brighter than ever before.

Conventionally, LCDs have been lit by Light Emitting Diodes (LEDs) in one of two ways – through a ‘frontlight’ method or through a ‘backlit’ approach. The problem is that while frontlight methods offer low power consumption, LCDs lit that way have a relatively low contrast too. Backlit methods on the other hand, offer a high contrast display but have a higher power consumption.

Omron engineers solved this dichotomy by combining a micro prism array with a nano prism array into the frontlight assembly of the LCD itself.

The micro prism array allows the path down which light emitted from the LED travels to be straightened, thereby spreading the light from the LED throughout the liquid crystal. This makes it possible to control the emission point and emission angle of the light radiating from the liquid crystal display screen, eliminating the maximum amount of light loss, achieving a brighter screen.

However, by applying the micro prism array to the frontlight in this way, light that enters the frontlight from LEDs, or from outside sources such as sunlight, causes reflection (optical noise) in the surfaces of the frontlight. Light coming from the liquid crystal display screen will then blend with this optical noise, leading to decreased image quality. However, if a very fine nano prism array is formed in the frontlight, this reflected light can be reduced.

Applying this theory, Omron created a nano prism array in the surfaces of the frontlight which complements the operation of the microprism in the display frontlight. According to the company, the technique achieves a three-fold improvement in contrast ratio compared to techniques used by other companies as well as a screen brightness that rivals that of a notebook computer.

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