The CCD/CMOS Sensor Challenge:
CCD and CMOS sensors are mature technologies that have revolutionized imaging in many applications. However, they have limitations that render these sensors nearly useless in less than perfect visibility conditions like rain, fog, and most of all at night in automotive applications or in medical imaging of the insides of our bodies, and in security surveillance in poorly lit areas, for instance.
- CCD Sensors: Higher quality, proven track record; Higher power consumption, lower speed, complex process, IR detection not possible
- CMOS: Lower power consumption, higher speed, easier and cheaper to manufacture; Requires suppression of pixel dispersion, IR detection not possible
- Single narrowband detection, multiple sensors required to cover wider spectrum
- UV detection: II-VI sensors
- Visible light: Si-CCD and Si-CMOS
- Near Infrared: III-V sensors, Infrared: Thermal sensors
- Very low quantum efficiencies (QE) away from peak
- Limiting application capabilities especially in poor visibility and at night
- Expensive to deploy multiple sensors
- Emerging need for a monolithic multispectral image sensor alternative
The Banpil Multispectral Image Sensor (BMIS) Solution:
BMIS is a unique multispectral (also known as multicolor) image sensor, which is a significant breakthrough and a technological paradigm shift over traditional sensors based on CCD and the more recent CMOS sensor technologies. Compare BMIS to leading CMOS sensor.
The patented Banpil Multispectral Image SensorTM (BMIS) will enable sensing capabilities across the entire wavelength region ranging from near ultraviolet light (UV), to visible light, past near infrared (NIR) to shortwave infrared (SWIR), and all within a monolithic sensor.
- Wide, Multispectral, 4-in-1 band coverage of entire wavelength
- Near UV, Visible, Near IR, Near Mid IR
- Single "Monolithic" Sensor performing multiple functions
- High Quality, Cost Effective
BMIS has a high dynamic range, high sensitivity over a broad spectrum, a high quantum efficiency, high speed, fast frame rate, and is low cost.
- High Dynamic Range
- Highest Quantum Efficiency
- High-Speed, High Frame Rate
BMIS is compatible with present standard semiconductor manufacturing processes.
| Banpil Multispectral Image Sensor Key Features |
Multispectral Response
- Wide/Broad Spectral Response
- Near UV, Visible, SWIR, Near Mid-IR
- 350 nm to 2500 nm
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Image Resolution
- Small Pixel Size 10µm X 10µm
- Scalable Technology to Larger Arrays (>1280x1024)
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Sensitivity
- Highest Quantum Efficiencies
- Low Noise to Signal Ratio
- High Dynamic Range (>190 dB) in system level
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Manufacturing and System Integration
- Standard Semiconductor Process
- High Uniformity Across Array
- Conventional Glass Optics
- Traditional Image Processing
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Multispectral Response
Banpil's Multispectral Image Sensor (BMIS) is a wide or broadband with 4-in-1 band coverage of the entire wavelength. As illustrated below, normally 3 (4th not shown) different kinds of sensors are required to achieve similar coverage that BMIS can in a monolithic sensor.
Sensitivity: Wide Spectral Band & High Quantum Efficiency
Comparing the Quantum Efficiency (QE) for BMIS, Silicon, Germanium and Indium Gallium Arsenide (InGaAs), the QE for silicon falls off rapidly in the NIR wavelengths, while InGaAs has respectable QE in the 1000 nm to 1700 nm wavelengths. Germanium or Si:Ge imagers while having appreciable QE from visible to the SWIR, they have high dark-current (leading to low signal to noise ratio) at room temperature. Only BMIS is capable of a consistently high QE greater than 90% over the entire spectral range of 350 nm to 2500 nm wavelength and therefore giving it superior performance over all other imagers.
Banpil's Sensor compared to other solutions
High Signal-to-Noise Ratio
Not only is BMIS QE, BMIS is expressly designed to have a very high Signal-to-Noise Ratio. The patented BMIS design, its thoughtful read-out integrated circuit (ROIC) design and its standard manufacturing process provide remarkable unmatched low noise performance.
Banpil Multispectral Image Sensor Compared to a Leading CMOS Sensor
| Properties |
Banpil Sensor |
Leading CMOS Sensor |
Benefits |
Spectral Range |
350 nm - 2500 nm
350 nm - 2000 nm
350 nm - 1800 nm
900 nm - 1800 nm |
450 nm - 950 nm |
Detects Near UV, Visible, SWIR, and Near Mid-IR with high QE over broad spectrum |
| Quantum Efficiency Visible (Blue) Light |
>80% @ 350 nm |
>40% @ 550 nm |
>2x consistently clearer, sharper, enhanced color images |
| Quantum Efficiency Near Infra Red (NIR) |
>95% @ 850 nm |
>35% @ 850 nm |
Clearer, sharper NIR images |
| Quantum Efficiency Shortwave IR (SWIR) |
>75% 2000 nm - 2500 nm |
0% - Non-functional |
Able to function in moonless, total darkness |
| Minimum Detectable Light |
<0.0001 lux |
<1 - 2.5 lux |
Able to "see" image in practically total darkness. No light projection needed like CMOS |
| Dynamic Range |
>190dB |
>70dB |
Higher quality images even in changing bright & complete dark conditions, Visibility in poor lighting, shadows, tunnels, snow, rain, night |
| Black-body Radiation |
Yes, works in dark (no light) |
Not possible, non-functional |
Ability to function in moonless night, no light |
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Manufacturing Process
BMIS is designed to be manufactured by using conventional semiconductor process. The technology is friendly to mass-scale production leading to low costs courtesy of to the global semiconductor infrastructure for process and cost improvements. The beneficiaries are OEMs targeting high volume expendable or disposable products. Using this approach in a fabless manufacturing strategy will lead to continuous improvement in cost and performance of BMIS, and also expand the universe of applications for this novel multispectral imaging technology.
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