Firms Show Off Next-gen Displays for Wearable Devices

May 28, 2013
Tetsuo Nozawa, Nikkei Electronics
A wristwatch-like device equipped with a 1.6-inch "Mirasol" display
A wristwatch-like device equipped with a 1.6-inch "Mirasol" display
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A smartphone having a 5.1-inch Mirasol display
A smartphone having a 5.1-inch Mirasol display
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Sharp's 2.6-inch "memory LCD" panel and its printed-circuit board (PCB). A CR 2025 button battery is mounted on the PCB.
Sharp's 2.6-inch "memory LCD" panel and its printed-circuit board (PCB). A CR 2025 button battery is mounted on the PCB.
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A reflective display newly developed by Japan Display
A reflective display newly developed by Japan Display
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Futaba's wristwatch-like device equipped with an OLED display
Futaba's wristwatch-like device equipped with an OLED display
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A few prototypes of wearable devices were exhibited at SID 2013. Many of them were equipped with next-generation displays that feature ultra-low power consumption, transparency, etc.

Qualcomm
Qualcomm Inc exhibited the "Wearable Form Factor," a wristwatch-like device equipped with the "Mirasol" reflective display using a MEMS technology, a smartphone, etc.

The display size, pixel count and resolution of the Wearable Form Factor are 1.6 inches, 600 x 600 and 577ppi (pixels per inch), respectively. Though the company did not disclose its power consumption, it consumes electricity only when its screen is rewritten.

Qualcomm has been engaged in the development of the Mirasol for the past few years, but it has been employed for only a few mobile devices and electronic book readers. And the company is recently being more enthusiastic about selling a product that uses a different MEMS display technology and was developed by Pixtronix Inc.

Nevertheless, as far as the exhibited device is concerned, the resolution and color display of the Mirasol have been drastically improved.

Sharp
Sharp Microelectronics of the Americas (SMA), the US arm of Sharp Corp, made a small display for the "Smart Watch" wristwatch-like smartphone by using the "memory LCD" technology, which equips each pixel with 1-bit memory, and exhibited it at SID 2013.

Though its 1.26-inch (144 x 168-pixel) memory LCD display is a transmissive type, it consumes only 15μW for displaying still images and 50μW for rewriting a screen image. Its responsiveness to video is 30ms. Currently, it can display only black-and-white images.

SMA plans to commercialize the "Agent" smart watch using the new display in December 2013. Also, it intends to add a Qi standard-compatible wireless power transmission technology to the watch.

Japan Display
Japan Display Inc (JDI) developed a next-generation display targeted at wearable devices and exhibited it at SID 2013. And it explained the details of the display at a symposium (lecture number: 50.3).

The display uses the "Memory-in-Pixel (MIP)" technology. Like Sharp's memory LCD technology, the MIP technology allocates memory to each sub-pixel though the memory LCD technology directly equips pixels with memory.

Moreover, JDI's display is a reflective LCD, and what Sharp exhibited at the show is a transmissive LCD. Furthermore, the display developed by JDI is capable of displaying 12 bits of colors (4,096 colors).

The 7.03-inch (768 x 1,024 x RGB) display exhibited by JDI consumes 3mW for displaying still images.

"When a movie is displayed at a frame rate of 60fps, a large amount of power is consumed for switching images, and its power consumption increases to 100mW," the company said.

For driving pixels, JDI used low-temperature polysilicon TFTs that enable to realize a high carrier mobility. As a result, the display is suited for displaying video, it said.

Futaba
Futaba Corp prototyped a smart watch equipped with a passive-matrix (PM) OLED display and exhibited it. It is not suited for displaying video. But, with its touch panel, it is possible to switch images by using a finger. At this point, the company is not planning to commercialize the watch.