In April 2019 Sony announced their 4th Generation
Pregius CMOS sensors - Pregius S. We are now seeing them released
in the latest models of the world's leading industrial cameras from
Adept Turnkey. Some of the Pregius sensors released to date include:
- The high speed models that run up to 159 fps IMX530 (24MP),
IMX531 (20MP), IMX532 (16MP).
- The standard models IMX540 (24MP), IMX541 (20MP) and IMX542 (16MP)
that run at up to 52fps.
The latest Pregius S sensors use a stacked pixel technology to reduce
size and increase performance. Sony's generational sensor improvements
continue to benefit image quality and applicability for a very wide
range of applications and none more so than embedded applications.
The key to the latest design improvements in Pregius
S sensors are Sony's proprietary Global Shutter function and the
fact that the Pregius S sensors have a back-illuminated pixel structure.
Previously all back-side illuminated CMOS sensors have been rolling
shutter. By altering the memory area position and shifting the associated
wiring, Sony gained an advantage that then allowed them to further
alter the architecture of the CMOS sensor. These changes allow the
pixel size to be reduced by 40% while boosting performance by more
than 165%.
Earlier sensors in the Pregius line are front-side
illuminated. Charged particles created in the photodiode are stored
right next to the photodiode to minimise charge shift delays, to
avoid image distortion and prevent light leakage. However metal
pads and wiring created occlusions for the photodiode, limiting
the light collecting area (and so sensitivity) as well as limiting
well depth and therefore dynamic range. This in turn created saturation
problems as well as limiting the miniaturisation of the pixel and
sensor.
The Pregius S sensors have back-illuminated structure
where the metal pads and wiring are placed behind the photodiodes.
With the occlusions removed it allowed Sony to reduce pixels from
3.45µm in their Generation 3 sensors to 2.74µm in these
4th generations sensors and yet maintain the sensitivity, saturation
quality and increase the resolution for the same size sensor. The
reduced pixel size and increase in resolution allows the Pregius
S to fit 20MP into the same sensor size that previously only fit
12MP. At the same time they increased Quantum Efficiency by 20%,
saturation signal volume per unit area by 44% and dynamic range
by 12%.
Speed has also been improved with the new pixel structure
and resulted in 2.4X faster output data rates, a significant boost
in high-speed throughput. Industrial applications benefit from performing
product inspections at wider fields of view with increased accuracy
and shorter measurement periods.
One of the yet unrealised benefits of the new pixel structure is
the future ability for Sony to add signal processing circuits to
improve sensor performance further and to add functions like smart
ROI, self-trigger, compression processing. Further miniaturising
the camera and capture system.
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