Slimmer mobile-phone screens on the way

Two flat-panel technologies are expected to generate super-skinny screens that will help bring down the cost and size of color-screen cellphones and personal digital assistants (PDAs).

One manufacturer claims the technology will give it an edge.

"By the end of this month we will be producing the newer and more advanced low-temperature polysilicon screens (LTPS) for handsets," Toppoly Optoelectronics Corp (統寶光電) spokesperson Wilma Wei said yesterday, claiming to be the first company in Taiwan to produce the new technology.

Toppoly spun off from notebook manufacturer Compal Electronics Inc (仁寶) in 1999, and started producing its first polysilicon screens last year.

Toppoly Ritek Corp (錸德) are the only two companies licensed by Eastman Kodak Co -- co-developer of the technology with DuPont Co -- to produce polysilicon screens in Taiwan, according to screen industry research firm DisplaySearch.

Polysilicon are a type of thin-film transistor liquid crystal display (TFT-LCD) that integrates computer circuits onto the glass of the screen. Previously the circuits were included on a separate chip that had to be built into the body of the phone.

"Manufacturers can build a simple system onto the panel, saving the cost of driver chips," said Wang Chien-erh (王建二), president of the Taiwan branch of DisplaySearch.

By end of this year more than half of the mobile phones and PDAs produced will use polysilicon screens, Austin Texas-based DisplaySearch predicted in January.

"The new polysilicon technology ... makes the display panels slimmer," Wang said.

This is especially important for the new generation of folding phones that have a second screen for caller ID on the outside of the case. It is also important for phones with built-in digital cameras that require a preview screen for snapshots, Wang said.

Digital also include a small TFT-LCD, and Toppoly's Wei claims that more than half of these devices will use polysilicon screens by the end of the year.

"Our screens reduce power consumption and improve resolution, making color screens brighter and prettier," Wei said.

Reducing power consumption lengthens battery life.

Another on the flat-panel scene is the organic light-emitting diode (OLED) which is a break from traditional TFT-LCDs. They are currently also in use in phones, PDAs and digital cameras.

"OLEDs are self-emitting, so they do not need a backlight, and they have no viewing angle restrictions as LCDs do," RiTdisplay Corp (錸寶科技) CEO Wang Ding Chang (王鼎章) said yesterday. "They are also one third thinner than polysilicon screens, and will be half the thickness of polysilicon screens in the future."

Founded 2000, RiTDisplay is a subsidiary of RiTek dedicated to the production of OLEDs.

DisplaySearch that OLED revenues will grow globally by 110 percent each year over the next four years to top US$2.2 billion.

OLEDs made from an organic material that, when a current is passed through it, emits light that is red, green, blue or a combination of the three. This removes the need for liquid crystals, color filters and a backlight and thereby reduces the size of the panel compared to LCDs, Wang said.

And thinning down is what the industry needs.

"If you go and talk to the device makers -- Motorola, Nokia, and Palm -- and ask the designers what is important in a display, the words we hear all the time are thinner and lighter," said John McMahon, a vice-president at California-based Vitex Systems Inc.

McMahon's has invented a super-thin protective coating for OLED displays that reduces the screen's thickness even further. OLEDs are particularly sensitive to moisture and currently have a sheet of glass glued onto them to keep moisture out. Vitex sprays polymer and ceramic layers directly onto the OLED screen, creating a protective barrier which water molecules cannot penetrate.

Vitex its technology with South Korea's Samsung SDI Co last month, and new phones are expected to hit the market by the end of next year, McMahon said. He also said he was actively seeking a partner in Taiwan that was currently manufacturing OLEDs. RiTDisplay is the only Taiwanese company commercially producing OLEDs, and would therefore be the most likely candidate.