17 Jun 2002
CMOS imaging sensors are catching up with the established technology of CCDs. Phillip Hill looks at the areas where CMOS is likely to stimulate new applications.
From Opto & Laser Europe June 2001
The emergence of complementary metal oxide semiconductor technology over the last couple of years will be a boon to image sensing applications in two key areas: the car industry and the wireless industry. So says a recent report from market research firm Frost & Sullivan, US.
Sales of four-wheel-drive vehicles have increased, as have concerns regarding how safe they are. These large vehicles have a high centre of gravity, which increases the chance of rollover and of inflicting damage in minor accidents. Manufacturers are turning to image sensors to improve safety features, such as controlled airbag deployment and collision-avoidance systems.
"The automobile industry has unlimited possibilities for image sensors, especially complementary metal oxide semiconductor (CMOS) sensors," said Frost & Sullivan industry analyst Nicole Wagner.
"The overall development of CMOS image sensors in the car industry can increase safety, especially in sport and utility vehicles. The industry is anticipating the use of CMOS technology in its production line of several different vehicles by 2004.
"CMOS image sensors are suited to car applications because the sensor is cheap," said Wagner. "The cost is especially important in items that are manufactured in large volumes where individual sensors are needed in each application."
The latest analysis, which is contained in World Image Sensor Markets, reveals that the entire image-sensor industry generated revenues of USD 2.4 billion in 2000. Frost & Sullivan projects that revenues will top the USD 6.5 billion mark by 2007. A large portion of revenues is expected to come from emerging CMOS technology.
In the late 1960s, Bell Labs researchers invented the charge-coupled device (CCD). Almost 40 years later, in 1998, CMOS sensors emerged to compete with conventional CCDs. Over the past year, CMOS technology has become a major contender in the image-sensor market, with infant manufacturers and mature CCD manufacturers alike competing for a share of the market.
It is estimated that the European image-sensor market will be worth USD 398 million by 2007,
up from USD 181 million last year. It has tremendous growth potential, owing to the manufacture of
components for the wireless industry, says Wagner. Europe is home to two of the largest wireless
phone and equipment manufacturers - Nokia and Ericsson. Each has the potential to be big
consumers of image-sensor chips.
The global leader in image sensors is Sony, which possesses an estimated 29.6% of the world
market. It not only produces CCD and CMOS devices but also manufactures end-user products, such
as camcorders and digital still cameras, maximizing its potential by fabricating and using its own
components in its products.
Matsushita and Sharp each have an estimated 14.8% of the market. Both firms make only
CCDs. However, they produce a full line of end-user products that incorporate the components that
they make.
Agilent Technologies Inc, formerly part of Hewlett-Packard, is the world's leader in CMOS
manufacturing and the fourth largest manufacturer of image sensors. In October 1998 it launched its
CMOS sensors with a digital imaging platform that would be modelled by many firms entering the
market. In November 1999, Agilent celebrated the shipment of its one-millionth CMOS sensor and
made possible the manufacture of a digital camera for sale to consumers for less than USD 100. It
currently has about 50% of the CMOS sensor market.
Number two on the market is ST Microelectronics. With its acquisition of VLSI, it has begun
research and development into a new generation of CMOS sensor that could offer a higher quality
than those currently on the market. ST Microelectronics holds an estimated 15% of the market.
In September 2000, Foveon announced the world's highest-resolution CMOS sensor with16.8
million pixels. The highest-resolution device prior to this was a 6 million pixel CCD sensor. The idea
that a CMOS sensor could be produced that was better quality than a CCD - a technology that has
been in existence for more than 25 years - made manufacturers begin to explore the possibilities of
CMOS devices.
"The technological innovation of the 16.8 million pixel device started a boom among CMOS
manufacturers in the research and development of all of the CMOS's capabilities," said Wagner.
In 1999, Basler Vision Technologies and Photobit collaborated on the development of machine
vision applications, which included CMOS sensors. Traditionally, Basler uses CCD sensors and
Photobit holds several patents for CMOS sensors. Basler should certainly benefit from the joint
venture. However, Photobit is also expected to benefit by having the opportunity to examine CCD and
CMOS sensor applications in the same production facility.
They are expected to pioneer a hybrid of CCD and CMOS sensors and offer solutions to the
inherent disadvantages of each technology. "This partnership could bridge the fierce competition
between competing CCD and CMOS technology and pave the way for other joint ventures," said
Wagner.
The cheap CMOS technology gives significant cost savings to the consumer through lowered
manufacturing costs. CCD production requires dedicated fabrication facilities that are exclusively
made for CCD manufacturing. CMOS devices can be manufactured in any standard wafer-fabrication
facility and can be made in virtually all microprocessors and memory-chip factories. Older technology
must compete with CMOS in volume of production, so CMOS technology could monopolize the
market as it advances. The CMOS sensor is still in the early implementation stages, but once CMOS
technology progresses, so will rapid, high-volume production.
CMOS devices cost USD 6-10, so the customer base is limited in the quality of products
offered. On the other hand, CCDs have a price range of USD 10-1000, which covers a variety of
products.
The average price of CMOS devices could fall somewhat as CMOS technology is used in
more and more applications. However, this average price should stay relatively close to the current
average price because it is substantially less than that for CCDs.
The CMOS sensor comes in two resolutions: video graphic array (VGA) and common
intermediate format (CIF). The VGA has an average cost of USD 10. The CIF is commonly used in
PC cameras and has an average cost of USD 6. The CIF is more common than the VGA in a ratio of
3:2.
CMOS technology allows multiple camera functions to be combined on one piece of silicon, so
CMOS sensors enable the manufacture of small hand-held cameras. Markets such as the automotive
and wireless sectors are anticipated to boost the market growth of CMOS sensors.
According to Frost & Sullivan, the car market has unlimited possibilities for image sensors,
especially CMOS sensors. Some of the potential applications are currently in the design stage. One
involves removing mirrors in vehicles and replacing them with a camera and a display. An advantage
of this is that there are virtually no blind spots and the driver can determine more accurately how close
another vehicle is.
Another design involves smart airbags. There is increasing opinion that children should not sit
in a front seat that has an airbag. The smart airbag can identify whether a child or an adult is in the
seat.
The car industry, with the assistance of sensors, has also begun designing collision-avoidance
systems that can sense other vehicles in the immediate area. When another driver gets too close, the
car slows down automatically. One of the most popular designs involves entertainment applications, in
which the driver can zoom in on attractions that are in the area.
Image sensors are also being designed for enhancing night- and infrared vision. However, the
automotive industry is historically slow to respond to technology because of long design cycles of
three to five years.
On the wireless front, Ericsson has formed an alliance with Chartered Semiconductor to
manufacture CMOS image-sensor chips. The chips can be used in a variety of applications, including
wireless videoconferencing.
Videoconferencing in wireless applications has tremendous potential, says Wagner, and
CMOS technology is anticipated to be the technology of choice in most applications. Wireless
equipment requires components with low battery consumption and, currently, CMOS technology has
compatible power consumption when compared with its counterparts. A steady increase in CMOS up
until 2003, followed by a boom in 2004, is anticipated. CMOS revenues in the wireless sector are
expected to grow at an annual compound rate of 45% between 2000 and 2007 according to the Frost
& Sullivan report. "Charging ahead" OLE October 2000 p23.
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