Image Sensors Attain Enviable Status with Technology Breakthroughs
Image sensors are increasing in importance with their growing number of applications.
Image sensors are increasing in importance with their growing number of applications. The advancement of different digital technologies is one of the main drivers for the development of image sensors. Functions that were previously independent or could not be integrated can currently be packed into one device. This is in line with the growing demand for compact devices, and also part of the push by manufacturers to differentiate themselves in the market. Image sensors form a core part of such compact devices, which use digital camera units.
B. Vertical End user Markets
Traditionally, charge coupled device (CCD) image sensors had superior dynamic range, higher resolution, and better noise level than complementary metal oxide semiconductors (CMOS). However, the resolution and data quality of CMOS image sensors has been enhanced to approach that of CCD image sensors. Given their lower manufacturing costs, coupled with such benefits as high speed, lower power dissipation, low power consumption, and small size, CMOS image sensors continue to make key inroads in a wide range of applications. Image sensors have penetrated into diverse application fields. The key vertical end applications in diverse markets are mentioned in the following chart.
(i) Consumer Electronics
Consumer electronics is one of the vertical markets poised for high growth, as various miniature and micro camera modules have been developed for use in smartphones. Key applications for which CMOS sensors are included within mobile phone cameras, digital still cameras, tablets, PC/laptops, web cams, televisions, gaming and toys and camcorders. CMOS image sensors are preferred over CCD sensors because of their lower power consumption, ease of integration, speed, and cost factor. In the present day consumer electronics scenario, data is stored in a digital format. Image sensors of a high-resolution, even in a miniaturized form, are possible due to the shrinking size of pixels. Image sensors of high-resolution can be a differentiator in mobile phones or tablet PCs, as these are expected to be a part of almost every cell phone in the near future. Moreover, image sensors create instrumental opportunities for other consumer electronics, such as television, video games, and electronic toys for gesture recognition. Image sensors (such as those that use time-of-flight technology) along with a light source can allow for sensing human gestures and tracking body motion in applications, such as gaming, remote control, and digital signage.
Image sensors play key roles in both diagnostic and monitoring equipments. Different types of image sensors are used in X-ray imaging, easy-to-swallow pill cameras, minimally invasive endoscopy, surgical robots, capsule endoscopy, digital tomosynthesis, mammography, as well as hyperspectral imaging in multiple applications that include medical diagnostics. Image sensors are required to be of very small size for endoscopy and smart pills. Capturing images and storing them in digital format reduces cost of storage and physical space for storage. 3-D imaging techniques, such as 3-D mammography, which provides a clearer view, also benefit from the use of image sensors.
Image sensors are used in various equipment designed for industrial applications. The main systems that are fitted with image sensors are machine vision systems, robots, wafer inspection, quality check, and printed circuit board inspection. Industrial inspection is essential for quality control and maximizing the yield in modern manufacturing. Machine vision systems are required for automation and removing the human element, for which image sensors are indispensable. A high adoption of image sensors is expected in this sector for machine vision, quality check, inspection, and robots. 3-D vision systems are key areas of application for image sensors, which can be used for industrial automation and machine vision. 3-D vision with high-speed cameras and laser light can perceive the depth and detect the shape of objects.
(iv) Security and Surveillance
Security and surveillance is one of the earliest end-user vertical markets that adopted image devices. The existing applications include site monitoring, intrusion prevention, homeland security, firefighting, home security, intelligent video, and pattern recognition A number of applications, such as homeland security, site monitoring, and home security, as well as uses in biometrics will fuel the growth of image sensors. Image sensors and supporting software are used for automated surveillance, and in biometrics (for example, face recognition biometrics, which compares selected facial features in an image with a database for authentication, recognition, access control, security, and so on). Warning generations are possible by capturing images and analyzing them using software.
Automotive is one of the most recent vertical end-user where image sensor based devices have been adopted to ensure not only passenger safety, but also pedestrian safety and assisting driver for safe driving on road. Lane departure warning systems, blind spot viewing, night vision, pedestrian detection, sign recognition, occupant classification for smart airbag systems, and automotive driver assistance systems are included applications within the automotive industry for image sensors.
(vi) Aerospace and Defense
High-quality imaging is the hallmark for different equipment used in aerospace and defense. Applications within this industry include site monitoring, aerial imaging, telescopes, space probes and hyperspectral imaging.
(vii) Traffic Monitoring Systems
To efficiently monitor traffic and toll booths, intelligent imaging devices have been developed. The most common applications include toll booth monitoring, speed checkers, license plate recognition and traffic estimation.
(viii) Scientific-Use Imaging Systems
Image sensors provide power to laboratory equipment for scientific experiments, analysis and interpretation of results. The key test equipment that use image sensor applications within the scientific community include spectroscopy, microscopy, crystallography, and fluoroscopy
C. Emerging CMOS Image Sensors
The difference in image quality between CCD and CMOS image sensors has minimized over the years. This, along with other important factors—such as ease of on chip integration, faster frame rates, and lower manufacturing costs—have propelled CMOS to overtake CCDs, especially in high-volume applications, such as consumer electronics. This trend is likely to continue, and in the future, CMOS will emerge as the primary image sensor in the market. CCDs will be used in applications that demand very high image quality (such as in high-end photography, scientific, space, industrial, etc.) and for applications in which price is not a major concern. A major challenge for CMOS image sensors is to implement a global shutter, which is essential for capturing fast moving objects. Advancements in technology have made it possible for CMOS image sensors to have a global shutter and this will enable CMOS to capture the industrial segment, displacing CCD over time.
Equipping a CMOS image sensor with a global shutter is a giant leap for this technology. The global shutter enables all the pixels to have the exposure at the same time (all pixels in the array integrate light simultaneously). This allows the capture of objects in motion without having the distortion caused by a rolling shutter. Major companies in the CMOS industry, such as Aptina, On Semiconductor, Sony, and Cmosis all have been able to employ the global shutter CMOS image sensors. Applications such as machine vision, surveillance, and others, where capturing objects in motion is required will benefit immensely due to this innovation
CCD was the image sensor that replaced films and vidicon tube, but advances in CMOS have pushed CCDs to operate mainly in higher-end or high-quality imaging applications. Despite this, CMOSs are making further encroachments with respect to CCDs, particularly in volume applications.
Miniaturization is an ongoing trend in electronics. Increasing the performance, as well as incorporating multiple functions in a single device have created complexity. Innovations in 3-D integrated circuit (IC)integration and quantum dots will help image sensors follow this trend. Pixel size is being reduced so that a greater number of pixels can fit in a small area, thus increasing the resolution of the image captured.
(ii) Increasing quantum efficiency
Quantum efficiency (QE) measures a device’s electrical sensitivity towards light. The better the QE, the better the quality of the image captured. An image sensor having a high QE is more effective than one with a lower QE, but with a higher resolution. Quantum film and backside illumination (BSI) architecture are innovations meant to increase the QE of the image sensors.
(iii) Higher Frame Rates
Higher frame rates are achieved by making the pixel readout process faster. This enables a greater number of frames to be captured per second. The greater the number of pixels in the sensor leads to a longer the readout time. Shrinking the area of concentration increases the frame rate. Innovation in this field benefits such applications as industrial, as well as security/surveillance, medical, and consumer electronics.
(iv) High Dynamic Range
In order to meet the requirements of surveillance, automotive, along with industrial and medical applications, image sensor manufacturers are focusing on increasing the dynamic range of the sensors. This allows high contrast in images, where the luminance of different objects can vary a great deal.
(v) BSI Architecture
Major companies in the image sensor industry, such as Sony, Omnivision, Aptina, Samsung, and Toshiba have all shifted to the back side illumination (BSI) architecture for image sensors. This type of architecture provides better quality images even in low light conditions than the previously used Front Side Illuminated (FSI) architecture. The ability to capture more light enhances the image quality and provides better images in low-light conditions. The consumer electronics market is adopting this architecture rapidly and BSI is likely to feature in most devices in the near future. The other industries will also benefit from this architecture as it replaces the FSI (front side illumination) that was previously used.
D. Key Technology Strength
In addition to the pixel size and number of pixels to improve image resolution, there are a host of other technology changes that drive the growth of the image sensors market. Reducing the consumption of required power, improving dynamic range, increasing sensitivity, and ensuring complete elimination of noise are some of the key technology improvements that enable increasing applications in diverse markets.
With improved image resolution the opportunities for image sensors are numerous and they continue to grow. Some of the hotbeds for image sensors include:
Smartphones that have imaging capabilities are driving the growth of image sensors for consumer electronics. In the future, this market is likely to face a point when the cost of the sensor will gain even greater importance.
The digital imaging capabilities of mobile phones have the potential to eat into the market of digital still cameras. For portability issues, people will prefer to have one device capable of fulfilling multiple needs and smartphones fit perfectly into this category. Nokia’s 41MP camera phone is a major step in this regard. Cameras with more than 8MP resolution will become the standard for mobile phones in the future and that will satisfy the needs of the majority of the population.
(ii) Other Opportunities
Image sensors will be able to provide artificial vision to people with partial or full blindness. Miniaturization of the sensors will play a key role in artificial vision for human beings.
Image sensors play a very important role in the automation of various processes. This includes manufacturing, packaging, traffic control, to name a few. Smart cities of the future will be packed with image sensors that will help in automating the various processes required to make human life more comfortable and easy.
There are chances that supply could possibly exceed demand as companies try to maintain or increase market share and possibly over-produce. This can lead to a situation with excess stock lying with the company and can affect them adversely.
F. Revenue Analysis
There are a large number of market participants in the image sensors market that have contributed
to a majority of the total revenue in the image sensors market. The world image sensors market in 2012 generated $4.718 billion in revenue. The annual growth for the total image sensors in 2012 was 9.8 percent and the total image sensors market is estimated to grow at a compound annual growth rate (CAGR) of 10.1 percent from 2012-2019.
The image sensor applications are increasing in both low- and high-end applications. The growth in revenue is supported by increase in applications aided by organic growth and also technological developments such as:
- 3-D Imaging
- Gesture Imaging
- Medical Imaging
- ADAS Systems
- Consumer electronics
The emerging CMOS technology applications have been contributing substantially to revenue.
The research and development in CMOS sensors is likely to be accompanied by greater applications in automotive, handheld communications (smartphones), audio-visual, optical mouse and other upcoming applications.
CCD image sensors also have exhibited growth, but at lower annual growth rates. However, the higher demand for digital still cameras, medical applications,machine vision, and automotive applications have contributed to higher revenues of the CCD image sensors. However, CMOS image sensor growth is also triggered by its penetration into the CCD applications market.
Both CCD and CMOS have unique capabilities that can be used in a variety of applications. CCD has a high-image quality with low noise. CMOS possesses on-chip capabilities, lower power consumption, and lower manufacturing costs. 3-D images offer a more real-life experience than 2-D images. Digital cameras providing 3-D imaging capabilities have already started to become available. Although these are priced on the higher side and sometimes require dedicated display devices for viewing purpose, this application area is expected to grow. Augmented reality is another area where 3-D imaging will be used. Image sensors also have huge potential in biometrics applications, including the areas of fingerprint scanners, palm scanners, and face recognition. These applications are required to enhance the security of devices, such as laptops, as well as security for homes and homeland security. Consumer electronics is a major market for image sensors and is expected to continue into the future as the volume of products is very high. Additionally, in the future, every mobile phone will consist of at least one camera. As opportunities proliferate in areas such as television, gaming devices, and Web conferencing, the sale of image sensors will receive a huge boost. In fact, image sensors are increasingly becoming a part of day-to-day functioning encompassing all vertical end-user markets.