Invention: Midnight caller-foiler

Technology 13 September 2005



Midnight caller-foiler

Ever been plagued by wrong numbers or midnight calls from far-flung time zones? No problem, says SK Telecom of Seoul.

Instead of the caller getting a standard brrrp-brrrp tone after dialling a number, their system allows subscribers to play a personalised message back to the dialler.


The approach works for fixed or cellphone lines, and the message heard by the dialler can be the subscriber’s number, name or nickname, interspersed with normal ring-tone and the time of day at the subscriber’s end. So anyone who has mis-dialled, or called from across the world and forgotten the time difference, immediately knows to hang up.

The subscriber sets the message by accessing a PIN-protected website, and can record a brief spoken phrase or enter text which is converted into generic male or female speech.

Or the user can program in a song (even if they can’t sing). A tone-deaf subscriber just types a short lyric and the server sets it to music. Lastly, companies could use the slot for a promotional message or jingle.

Read the ring-ring message patent here (pdf format).

Battery-beating LCD

Motorola has a two-pronged plan to reduce the battery drain from the large, bright screens needed to show video on mobile TVs, PDAs and cellphones.

Conventional LCD screens have a mosaic of tiny red, green and blue filters, and a white backlight. The filters absorb a lot of light, so the backlight has to be drainingly bright.

The company’s first prong is to use a monochrome LCD, with no filters. The screen shows grey scale pictures, with red, green and blue organic LEDs switching on when colour is required, which Motorola says is more efficient. The screen is refreshed at three times the normal frequency and produces smooth colour motion.

The second prong is to use solar power to help charge the device. Because there are no colour filters in the LCD, 70% of ambient light passes freely through the screen and the near-transparent thin-film organic LEDs to a back-of-screen solar panel. This trickle charges the battery. What is more, waste light from the back of the LEDs – about 10% of their output – is reflected back onto the solar cell.

Read the battery-beating LCD patent here (pdf format).

Snappy prints

Australian inventor Kia Silverbrook is snapping at Polaroid’s heels. His company Silverbrook Research has been filing a string of patents on a new approach to instant-picture photography.

Instead of buying a Polaroid camera, plus packs of instant picture film with a built-in battery, Silverbrook will rent you a disposable digital camera with built-in memory, colour printer and battery.

When the printer runs out of paper, the camera is returned for a partial refund or a credit against a new one. The used cameras are re-cycled by clearing the memory, recharging the batteries, adding new paper and topping up the ink.

The heart of the camera is a high-quality printer, made from a four-part silicon strip etched with inkjet holes and fed by three colour ink reservoirs. A motor feeds the paper roll over the printer head, and a guillotine chops off the finished postcard-sized prints.

Because the camera lens and electronics are re-used, the manufacturer could afford to fit a 1.5 megapixel image sensor and a 1600 dpi print head. And digital image capture allows image processing, with Holly borders for Christmas shots, pumpkins for Halloween and sepia tone and hearts for wedding pictures. Say “cheesy”.

Read one of the key click-and-print camera patents here.