Trends:
Can Anything Stop the Growth
in
Camera Phone Popularity?
The tsunami of digital photos
people are snapping today
is dramatically reshaping
the entire digital imaging
ecosystem. Social networking
Websites such as MySpace
and YouTube have driven enormous
increases in image uploading,
while the availability of
photo- and video-sharing
sites ranging from Flickr
to iMovies have spurred additional
volumes of downloading. And
today, uploading and downloading
of photos and video occurs
not just to and from PCs,
but among a wide range of
devices PCs, laptops, PDAs
and camera phones.
NEW Toshiba Corporation Launches Highly Sensitive CMOS Image Sensor with BSI
Toshiba adds a new CMOS image sensor that will bring 14.6 million pixels to digital still cameras and to mobile phones supporting video imaging. The sensor, the latest addition to the Toshiba Dynastron™ line-up, is also the company’s first to integrate the enhanced sensitivity offered by back-side illumination technology (BSI) using a 65nm process and the world's first 300mm wafer lines for BSI technology. Press Release
8MP Image Sensors and 2MP Chip Scale Camera Modules and
New ImaTuning™ Image Sensor Calibration Tool
Toshiba has expanded its line of Dynastron® image sensor and chip scale camera modules (CSCMs) with the introduction of a new 8-megapixel (MP) CMOS image sensor and a 2MP CSCM in a 1/5-inch optical format. Both of these devices use Toshiba's 1.75-micron image sensor process technology which was designed to address the needs of the mobile handset market by delivering large pixel counts in a small form factor and capturing high-quality images in low-light conditions. The 8MP Dynastron image sensor (part number ET8ER4-AS) is designed for use in high-end camera phones that offer auto-focus or optical zoom capabilities. The 2MP CSCM uses Toshiba's through chip via technology to allow mounting and assembly of camera components in the chip wafer during manufacturing to reduce the module's size by as much as 64 percent in comparison to other camera modules. Press Release
Designed for quick and efficient color tuning, the new Toshiba ImaTuning™ image sensor calibration tool consists of both hardware and software for rapid color calibration and tuning of Toshiba CMOS image sensors for cellular handsets and other mobile applications. Press Release
Datasheets for Toshiba images sensors and Chip Scale Camera Modules are available under NDA. Contact TechQuestions for more information.
Toshiba:
the Leader “Behind the
Scenes”
in Image Sensors
Toshiba is a pioneer and
world leader in image sensor
technology – both for
charged-coupled devices (CCDs)
and complementary metal oxide
semiconductor (CMOS) image
sensors. Toshiba’s
leadership advancement and
technology refinement during
20 years of designing, developing
and manufacturing image sensors,
includes over 10 years in
the specific development
of CMOS image sensors, the
heart of the camera phone.
As a result, Toshiba holds a significant share of the market and now ranks as #2 according to Gartner's June 2008 Top 10 Vendor Ranking by Total CMOS Image Sensor Revenue, Worldwide 2007 Report.
The Tech Challenge 101 initiative is designed to help marketing and corporate executives expand their knowledge of CMOS image sensor technology and cell phone design through a quick-read series of focused insights and articles.
There are many criteria that can be used to choose an image sensor. Some of them are qualitative/subjective and some are quantitative/objective. When shopping for a CMOS image sensor for a camera phone, there are a few important “must know” quantitative metrics to keep in mind. They are:
1. Pixel density – pixel density is a fundamental part of an image sensor's performance; the more pixels the sensor has, the more detailed the picture can be. But when selecting an image sensor, designers should not look at pixel count alone. As pixels decrease in size, they also decrease in performance. In order to add more pixels to sensors without compromising image quality, sensor vendors are working with a variety of new technologies to enhance pixel performance, and designers should be aware of what pixel technologies their vendors are using to boost performance as they shrink pixel size.
2. Sensitivity - sensitivity measures the response of the sensor to light stimulus. It is often measured as mV/lux·sec. More
NEW White
Paper:
Toshiba Dynastron-WD™ Wide
Dynamic Range Technology for
CMOS Image Sensors
To
date, image sensor
vendors have focused
on delivering low-light
performance, but
there is increased
demand for high-quality
performance under
bright light conditions
as well.
When
the pixel wells
are full, they
overflow and detail
is lost, a phenomenon
called blooming.
A wide dynamic
range sensor can
avoid
such problems and capture
a much higher level of
detail than a normal
sensor can.
The
Toshiba Dynastron-WD™ technology
can extend dynamic
range of a CMOS
image sensor up
to 96dB. It
is a critical capability
in today’s highly
competitive camera
phone market.
Trends:
Can Anything Stop the Growth in Camera
Phone Popularity?
--By
Shri Sundaram, Business Development Manager,
Toshiba America Electronic Components,
Inc.
The tsunami
of digital photos people are snapping today
is dramatically reshaping the entire digital
imaging ecosystem. Social networking Websites
such as MySpace and YouTube have driven
enormous increases in image uploading,
while the availability of photo- and video-sharing
sites ranging from Flickr to iMovies have
spurred additional volumes of downloading.
And today, uploading and downloading of
photos and video occurs not just to and
from PCs, but among a wide range of devices – PCs,
laptops, PDAs and camera phones.
Camera Phones
Explode with Growth
The camera phone is the most disruptive
of these devices. Analyst firm Gartner
notes that camera phones accounted for
48 percent of total worldwide mobile
phones sales in 2006 and will jump to
81 percent by 2010.1 Unit
sales of phones will grow from 460 million
handsets sold in 2006 to one billion
phones sold by 2010.2
Poor picture quality, limited camera
phone memory and lack of an "ecosystem " to
move pictures out of the phone and onto
PCs or other storage devices might have
made camera phones little more than a
fad. But, a new wave of emerging technologies
have both encouraged early adopters to
use their camera phones more and attracted
a new set of users that would not have
purchased a camera phone when features
were so limited. As a result, just as
digital still cameras dramatically shrunk
market demand for film cameras, new and
improved camera phones are now impacting
sales of digital still cameras.
History Repeats
Itself as Camera Phones Replace Digital
Camera
As late as 2005, many industry
experts predicted that camera phones would
never replace digital still cameras as
the primary photography device for consumers,
citing "fuzzy" images, low resolution and
a host of other issues. Many of these experts
are the same people who predicted that
digital cameras would never replace film
cameras.
Today, camera phone sales
are surging as digital camera sales are
stalling. Among the reasons: digital camera
sales are reaching a saturation point with
current technology. Multiple studies have
shown that the average U.S. family of four
already owns two or more digital cameras.
On the other hand, improved camera phone
technology, analyst firm Strategy Analytics
notes will result in camera phones capturing
15 percent of the low-end digital still
camera market by 2010. 3
A recent survey by German optics firm
Schneider Kreuznach polled 1,000 users
in the U.S., Germany, China and India
regarding their usage patterns, highlights
of their findings include:
One out of four respondents indicated
that in the future they would exclusively
use cell phones for picture-taking
(early adopters), provided the quality
matched that of today's upper mid-range
digital cameras with approximately
6 million pixels.
Under certain circumstances, 43
percent would be willing to replace
their digital camera with a suitable
cell phone. At present, only 32 percent
would still prefer a digital camera.
Users in India and China were particularly
open-minded towards cell phone photography:
In these countries, eight out of ten
of those questioned (79 percent) could
imagine using only cell phones for
picture-taking in future.
While in India and China more than
half of all respondents (60 and 52
percent respectively) already take
pictures with their cell phones several
times per week and in the USA more
than a quarter (26 percent), Germany
has the lowest number of so-called
'power users' (12 percent) and at the
same time the highest number of non-users
(59 percent).4
It is not a matter of if, but
of when camera phones will
become the primary photography device
for consumers. Toshiba sums up this trend
with the chart below:
As digital still cameras proliferate,
film cameras have been relegated to some
professionals and hobbyists. This trend
will repeat itself with digital cameras
as camera phone features improve.
New Camera
Phone Technologies Enhance
Image Quality
One
key trend in camera phone image sensors
is the shrinkage in pixel size. A standard
pixel in a digital still camera has an
area of 36µ² . The typical
camera phone pixel consumes an area of
5µ². On the one hand, the
smaller pixels in a camera phone enables
higher resolution; on the other, smaller
pixels capture less light resulting in
poorer picture quality, especially in
low light conditions.
Another key trend is the need for extended
depth of field. A normal feature of most
digital still cameras, this has been
a feature that's been missing in camera
phones until recently.
In optics, particularly film and photography,
the depth of field (DOF) is the distance
in front of and beyond the subject that
appears to be in focus. There is only
one distance at which a subject is precisely
in focus, but focus falls off gradually
on either side of that distance, and
there is a region in which the blurring
is imperceptible under normal viewing
conditions.5
New solutions, such as the Toshiba Wide
Dynamic Range technology, provide enhanced
tonal quality at all ranges. As image
sensor developers addressed low light
condition issues, their solutions created
problems with well-lit situations – images
would often bleach out.
While previous solutions only provided
a CMOS image sensor dynamic range of
up to 60 dB, the new Toshiba Wide Dynamic
Range technology extends this to 92 dB.
Camera phones can now capture high-quality
images in both low-light and bright-light
situations.
Improvements in image sensors combined
with new features such as auto focus
and zoom within the camera phone are
combining with other advancements to
create a complete camera phone "ecosystem" that
consumers are using to share, store and
print camera phone images as easily as
they do digital still camera images.
Among these:
Advancements in cellular networks
in the form of both upgrading 2G networks
with technologies such as EV-DO, as
well as the spread of 3G networks (in
several flavors, such as GSM, GPRS
and UMTS), makes it easier and faster
for consumers to send their photos.
Camera phone memory capacity is increasing
rapidly and shrinking in size to accommodate
the storage of more images.
Camera phone display quality is improving.
While VGA screens are too expensive
today, prices are coming down.
Handset manufacturers are designing
a new breed of phone that includes
a larger screen. For example, certain
new models pivot 90° vs. flipping
up to provide a screen with an aspect
ratio much closer to today's 4:3 or
16:9. As a result, the screen size
is nearly the same as the footprint
for the entire phone.
Manufacturers are also integrating
additional radios into phones, such
as Bluetooth, WiFi and soon WiMax to
give consumers additional options for
their photos, sharing with friends,
moving onto a PC or storage device,
etc.
Lyra
Research notes that by late 2008 or early
2009, "The cumulative number of camera
phones shipped will surpass the cumulative
number of both conventional and digital
cameras shipped in the entire history of
photography – and camera phones will
have been on the market for less than a
decade." 6 As the march
of new technologies continues, even today's
camera phones will give way to "intelligent" phones
that include features such as image recognition – where
the camera will "recognize" a
person or scene being photographed and
group like photos together. New features
are limited only by manufacturers' imaginations.
References
1 iT Wire, Every Cell Phone
a Camera-Phone Soon, Says Gartner," November
6, 2006.
2 iT Wire, Every Cell Phone
a Camera-Phone Soon, Says Gartner," November
6, 2006.
Toshiba:
the Leader "Behind the Scenes"
in Image Sensors
Toshiba is a pioneer and world
leader in image sensor technology
both for charged-coupled devices
(CCDs) and complementary metal
oxide semiconductor (CMOS) image
sensors.
Toshiba’s leadership advancement
and technology refinement during
20 years of designing, developing
and manufacturing image sensors,
includes over 10 years in the specific
development of CMOS image sensors,
the heart of the camera phone.
As a result, Toshiba holds a significant share of the market and now ranks as #2 according to Gartner's June 2008 Top 10 Vendor Ranking by Total CMOS Image Sensor Revenue, Worldwide 2007 Report.
5
Reasons Toshiba Has Your
Back
Why
corner
yourself?
See
why
Toshiba
is
preferred
by
world-leading
mobile
phone
makers.
Toshiba’s
market strength in image sensor-based
camera applications is based
on superior image quality,
consistently innovative products
and on the strong relationships
forged with top-tier mobile phone
manufacturers. Tight engineering
and procurement team relationships,
as well as superior “Benchmark” customer
service have become the hallmark
of Toshiba.
Preferred
Camera Phone Image Quality
The Toshiba portfolio encompasses
a family of CMOS image sensors
from VGA and above for predominately
high-end, camera-enabled mobile
phone handset applications,
including Smart-phones.
Toshiba Dynastron™ CMOS image
sensors employ a unique pixel
design that enable high-quality
images with both high sensitivity
and signal-to-noise ratio, even
in low-light conditions. Based
on TAEC evaluation, Dynastron
CMOS image sensors have proven
their superiority in image quality
comparisons by offering demonstrably
better colorrepresentation and
low-light performance compared
to other leading CMOS image
sensor products. Toshiba image
sensors deliver best-in-class
image quality through continued
innovations in:
1. Unique pixel structure development
2. Proprietary semiconductor process
technology
3. Advanced micro lens and color
filter technology
4. Proprietary image pipeline technology
Market-Driven
Engineering and Manufacturing
Toshiba is dedicated to the development
and application engineering of imaging
products. Two of the company’s
wafer fabs, located in Iwate and
Oita, Japan, are focused on CCD and
CMOS image sensor manufacturing.
A large number of module partners
design, develop and deliver camera
and sensor modules using Toshiba
image sensor wafers.
To stay current with
the latest technology
developments, emerging
applications and standards,
Toshiba plans a multi-billion
dollar investment in Capex
and R&D over the next
several years.
The Tech Challenge
101 initiative is designed to help
marketing and corporate executives
expand their knowledge of CMOS image
sensor technology and cell phone
design through a quick-read series
of focused insights and articles.
Please check back periodically for
new tech topics.
Featured
Article: "Color
Theory Behind the Scene:
Color
Calibration of a CMOS Image
Sensor"
--By
John Lin, Senior Design Engineering
Manager,
Toshiba America Electronic
Components, Inc.
Highlights:
How the human eye perceives
color plays an important
role in developing good
image quality with accurate
color representation.
Light is considered a
form of electromagnetic
radiation. The visible
wavelength is from 380
to 780nm. The color of
the light depends on the
distribution over the spectrum.
Different wavelengths appear
as different colors.
The color of an object
is defined by two spectra:
the surface reflectance
of the object and the light
source shining on it. The
product of these two spectra
is the light that enters
the eye and stimulates
the cones.
Understanding
Color Representation
Accurate
color representation is one of the
most important aspects in evaluating
the image quality of an image sensor.
To fully understand color representation,
one must first be knowledgeable in
the age-old science of color theory
and how it plays a critical role
behind the scene in converting the
real world into electronic images
using advanced image sensor technology.
To
explain, in a simple fashion, how
color is reproduced and calibrated
in the CMOS image sensor from Toshiba
using a software-based system, it
is important to first cover the topic
of color vision. How the human eye
perceives color plays an important
role in developing good image quality
with accurate color representation.
First
of a Series: What a Study
of Color Vision Reveals
This
is the first in a series
of articles on color
theory and how it is
used in CMOS image sensor
color reproduction from
sensor to printer and
display.
Human
vision starts with
light striking
the retina. The photoreceptor
cells in the
retina encode light
into signals that
are interpreted
by the brain to
generate the perception
of color. There
are two basic types
of cells—cone and
rod. Cones generate
the color perception
information
and rods are responsible
for night vision.
There are three
type of cones that
are sensitive to
different wavelengths
of light—long,
medium and short
wavelength cones
or informally red,
green and blue
cones.
Visible
Light - A Function
of Spectral Distribution
Light
is
considered
a form
of
electromagnetic
radiation.
The
visible
wavelength
is
from
380
to
780nm.
The
color
of
the
light
depends
on
the
distribution
over
the spectrum.
Different
wave-lengths
appear
as
different
colors.
Fig.
1 shows
10
types
of
spectral
distribution
of
10
daylight
sources.
The
area
beneath
the
curve
is the density
of the energy,
which is
a measure
of brightness
to human
vision.
Cone
Response
Curves
The
cone and
rod cells
show the
following
absorption
characteristics.
The
color
of
an
object
is
defined
by
two
spectra:
the
surface
reflectance
of
the
object
and
the
light
source
shining
on
it.
The
product
of these
two
spectra
is
the
light
that
enters
the
eye
and
stimulates
the
cones.
The
signal
sent
to
the
brain
is
the
product
of
input
stimulate
and
the
cone
response.
This
is
the
foundation
of
the
color
vision
theory.
Trichomacy
and Metamersion
The
encoding created by the
cones means that every
spectrum is represented
by exactly three signals.
This is the principle
of trichromacy. Digital
colors are encoded as
three primary colors
due to trichromacy.
The principle of metamerism
states that different
spectra that produce
the same encoded signals
look like the same
color to the human
eye. Color is defined
by the product of cone
response multiplied
by input spectrum,
not the spectrum alone.
This means that if
two light sources have
the same apparent color,
then they will have
the same tristimulus
values, no matter what
different mixtures
of light were used
to produce them.
The principle of metamerism
underlies all color
reproduction technologies.
Instead of reproducing
the original spectrum
distribution of the
color, it is possible
to create an equivalent
response or metameric
match by mixing the
three colors.
Trichromacy and metamerism
are used to create
instruments that measure
color. They allow colored
material to be described
quantitatively and
create metrics that
define when colors
match.
Colorimetry
is the science of color
measurement. It is based
on the study of human
matching colors. Colorimetry
is used to create color-matching
functions that can be
used to convert any spectrum
into a standard encoding.
CIE
1931 Color Space
As
mentioned, cone response
and trichromacy are the
foundation of color theory.
In order to measure color
with three numbers, the
concept of color space
is used to associate
and visualize a color
with three numbers.
One of the first mathematically
defined color spaces
was the CIE XYZ color
space (also known as
CIE 1931 color space),
created by the International
Commission on Illumination
(CIE) in 1931.
However, the CIE XYZ
color space is unique,
because it is based
on direct measurements
of the human eye, and
serves as the basis
from which many other
color spaces are defined.
In the CIE XYZ color
space, the tristimulus
values are not the
S, M, and L stimuli
of the human eye, but
rather a set of tristimulus
values called X, Y,
and Z, which are also
roughly red, green
and blue, respectively.
In the 1920s, W.
David Wright and John
Guild independently
conducted a series
of experiments on human
sight, which laid the
foundation for the
specification of the
CIE XYZ color space.
The experiments were
conducted by using
a circular split screen
two degrees in size,
which is the angular
size of the human fovea.
On one side of the
field a test color
was projected and on
the other side, an
observer-adjustable
color was projected.
The adjustable color
was a mixture of three
primary colors, each
with fixed chromaticity,
but with adjustable
brightness. The observer
would alter the brightness
of each of the three
primary beams until
a match to the test
color was observed.
Not all test colors
could be matched using
this technique.
When this was the
case, a variable amount
of one of the primaries
could be added to the
test color, and a match
with the remaining
two primaries was carried
out with the variable
color spot. For these
cases, the amount of
the primary added to
the test color was
considered to be a
negative value. In
this way, the entire
range of human color
perception could be
covered. When the test
colors were monochromatic,
a plot could be made
of the amount of each
primary used as a function
of the wavelength of
the test color. These
three functions are
called the color matching functions
for that particular
experiment.
Based on the result,
in 1931, CIE standardized
the color matching
function (CMF) by mathematical
transformation (into
x,y,z) in which there
is no longer any negative
value. It is an abstract
curve now. No physical
light can generate
the function.
The
CIE 1931 Standard
Colorimetric Observer
XYZ functions is
the CMF now widely
used. The XYZ color
space is calculated
using the formula
shown left.
This
article has reviewed
key findings and
thories of color
vision. Future
articles will introduce
how theories learned
from the study
of color vision
are used in CMOS
image sensor color
reproduction and
how the color is
managed from sensor
to printer and
display.
Toshiba
has pulled together a peer team deeply
in volved in the technology, marketing
and finance of CMOS Image Sensors.
We believe that a Peer-to-Peer Question
and Answer format provides the right
venue to address your immediate questions.
Just click on the link below,
complete your contact information,
type in your CMOS image sensor
question, and you will hear from
us soon. Ask
Toshiba now.
Behind
CMOS Image Sensor Technology, Marketing
and Finance
CIS
Focus
|
Question
Technical
What are the tradeoffs between a Fixed Focus Module and an Auto Focus Module assuming both modules are using the same image sensor die?
Answer:
A Fixed Focus Module's lens is in a fixed position within the module. Therefore, there is an optimum distance from the module where the image of the object will be the sharpest. At any other distance, closer or further away, the object's image will be not as sharp. Auto Focus Module has a AF Driver inside that physically adjusts the lens position based on the Image Signal Processor's Auto Focus Algorithm. This means that the distance from the module where the image of the object will be the sharpest can be adjusted. However, once the position is fixed, any object closer or farther than the new focused distance, will not be as sharp. If that is the case, why would anyone want a Fixed Focus Module? Well, it all comes down to cost and reliability. At a minimum, the Fixed Focus Module does not need the Auto Focus Module's Auto Focus Actuator. Also, since the Auto Focus Actuator is mechanical, it is more prone to breakage than a Fixed Focus Module.
What are the tradeoffs between sensitivity and pixel size?
Answer: Sensitivity is a measure that’s independent of the size of the pixel or package dimension. It is the measure of an image sensor pixel’s ability to sense the photons (light) and generate electrons (signal) depending on the frequency (color) and luminance (brightness) of the light. However, smaller pixel means fewer photons, which in turn means fewer electrons. So, smaller pixels lead to smaller output signal. When the pixel size gets smaller, emphasis is given on reducing noise levels proportionally.
Marketing
What
new applications are being developed
for cell phone cameras?
Answer:
A traditional application has been
the point-and-shoot camera. However,
newer applications that are on
the horizon include video conferencing,
camcorders, barcode scanning, pattern
recognition, etc.
Finance
How can using a Chip Scale Camera Module reduce my overall bill of material (BOM) costs?
Answer: Toshiba's Chip Scale Camera Module (CSCM) is reflowable/solderable. Therefore, you can solder Toshiba's CSCM directly onto the PCB. There is no need to pay for an extra socket like conventional socketable modules. Please contact Toshiba and your preferred PCB supplier to work out the technical details.
What are the primary cost contributors (components) of a camera module used in a Supply Chain cellular telephone?
Answer: The primary components that go into an image sensor module include an image sensor (with imaging area and usually A/D converter) mounted on a PCB, image signal processor, base and IR cut filter, lens barrel, and lens. Generally, in higher resolution camera modules, the auto focus and optical zoom functions are also cost components.
One
key trend in camera phone image sensors
is the shrinkage in pixel size. A standard
pixel in a digital still camera has an
area of 36µ² . The typical
camera phone pixel consumes an area of
5µ². On the one hand, the
smaller pixels in a camera phone enables
higher resolution; on the other, smaller
pixels capture less light resulting in
poorer picture quality, especially in
low light conditions.
Toshiba Dynastron™ CMOS image
sensors employ a unique pixel
design that enable high-quality
images with both high sensitivity
and signal-to-noise ratio, even
in low-light conditions. Based
on TAEC evaluation, Dynastron
CMOS image sensors have proven
their superiority in image quality
comparisons by offering demonstrably
better colorrepresentation and
low-light performance compared
to other leading CMOS image
sensor products. Toshiba image
sensors deliver best-in-class
image quality through continued
innovations in: 
Accurate
color representation is one of the
most important aspects in evaluating
the image quality of an image sensor.
To fully understand color representation,
one must first be knowledgeable in
the age-old science of color theory
and how it plays a critical role
behind the scene in converting the
real world into electronic images
using advanced image sensor technology. 
