Mobile phones with camera modules are becoming very popular, and by the end of 2002 they may surpass digital cameras in shipments in Japan.
With their better performance, some camera-equipped mobile phone models have begun to be used for low-priced digital cameras. Expecting the market expansion, many imaging-device manufacturers are competing intensely. At the same time, the market expects the introduction soon of interline-transmission (IT)-format charge coupled devices (CCDs).
Mobile Phones with Cameras, New ‘Must-Have’ Items
Mobile-phone handsets with camera modules are selling well in the now-mature mobile-phone market.
According to J-Phone Co., Ltd., the cumulative number of its handset units surpassed 3.5 million as of February 2002, since its introduction of “Sha-mail (‘e-mails with photography’) handsets in November 2000. This figure accounted for about 30 percent of all the handsets by J-Phone currently used in the market. Seeing this trend, NTT DoCoMo Inc., TU-KA Phone Group, and au Group have started to offer mobile phones with camera modules.
Today, phones with cameras offer many functions. Cheap-quality photographs taken for showing to others for fun — represented by those taken by “Print Club” (sticker vending machines) — are no match for the camera-capable phone. If mobile phones have camera modules, people can e-mail photographs, and they don’t need to make prints to give them to others. This convenience is very powerful, and may overtake conventional instant cameras for image communication.
In 2002, imaging-device manufacturers began to improve the image quality of photos taken by mobile phones. Image quality is being improved so that it is getting closer to that of photos taken by conventional low-priced digital cameras. The number of pixels of conventional cameras on mobile phones was about 352 x 288 (CIF) at most. However, the J-SH51 model, which became available in March, from J-Phone, can record 640 x 480 VGA-type images.
The possibility that camera modules of mobile phones will evolve further toward high-quality digital cameras is increasing. For example, Minolta Components Co., Ltd. and Toshiba Corp. are now developing compact optical zoom units for mobile phones. Minolta’s 2x zoom unit will be commercialized soon, and within 2002, mobile phones with zoom lenses are likely to be available. Toshiba’s zoom unit and auto-focus unit support a 1/4-in. optical system. In the future, they may expand their market share and even “overwhelm” the sales of normal digital cameras.
Imaging-Device Makers Lured to Camera Modules
The imaging-device industry has been expecting a lot in the market of mobile phones with camera modules. If 10 percent of all the mobile phones shipped in the global market have built-in camera modules, demand would comprise 40 million units a year. Although the unit price of an imaging sensor is low, its market potential is large compared to the digital camera market.
Expecting such a large possibility, more than ten makers plan to develop and market compact imaging sensors. In addition to main players, such as Toshiba, and Sharp Corp., several others, including Seiko-Epson Corp., Fujitsu Ltd., and Hitachi Ltd., have started making imaging devices. Matsushita Electric Industrial Co., Ltd., with its long history of manufacturing CCD solid-state imaging devices, announced its new CMOS devices. Within this year, Agilent Technologies Inc. of the United States, which is a leader in the global CMOS sensor market, will introduce CMOS sensors for mobile phones.
Will IT CCD Continue to Be Dominant?
Mobile-phone service providers and handset manufacturers request the following as their criteria for camera modules for mobile phones: high-resolution imaging, low power consumption, compactness in size, and price competitiveness.
CMOS-type solid-state image sensors have been chosen to meet such requirements because of their sizes and low levels of power consumption. A dozen cellular phones now available have CMOS image sensors.
However, CMOS sensors have weaknesses as to noise reduction, and they have issues with sensitivity and color reproduction. In February 2001, CCD solid-state imaging devices became available from Sanyo Electric Co., Ltd., and those devices have high sensitivity. Adopting the frame-transmission (FT) system, Sanyo enabled low power consumption compared to CCDs with the interline transmission (IT) system. IT CCDs are mainstay CCDs for digital cameras and camera-enabled VCR systems. Sanyo also succeeded in making the size smaller.
Meanwhile, makers of CMOS solid-state image sensors introduced CMOS with FT-equivalent sensitivity, by optimizing imaging processes. First, Sharp, in April 2001, and then Matsushita Electric and Toshiba introduced them.
Inotech Corp. claims that its voltage modulation image sensor (VMIS) series have the image quality equivalent of that realized by FT. In the fall of 2001, Inotech made 1/7-inch optical devices for CIF with the FT-equivalent definition. Then, Seiko-Epson, with a technical license from Inoteck, started applying the VMIS techniques to develop an ACDT image sensor.
CCD vs. CMOS
In mid-2002, the competition in pursuit of quality will reach a new stage, when the quality targets changes from FT quality to IT quality. Until now, CCD solid-state image sensors have dominated the conventional camera applications such as for digital cameras and VCRs with camera modules. However, experts say that they will soon face challenges by imaging devices of mobile phones.
Many studies have found that CMOS image sensors have more potential advantages (except the image quality).
CMOS will suffice in digital cameras and camera-enabled VCRs only if the image quality is improved. If image quality does not improve in CMOS-mounted products, it will not replace IT CCD products.
Until now, three major CCD manufacturers, Sony, Matsushita, and Sharp, have not announced IT CCDs for mobile phones. But they say they will introduce the products when they receive orders from handset makers.