Curved CMOS sensor: characterization of the first fully functional prototype

Many are the optical designs that generate curved focal planes for which field flattener must be implemented. This generally implies the use of more optical elements and a consequent loss of throughput and performances. With the recent development of curved sensor this can be avoided. This new technology has been gathering more and more attention from a very broad community, as the potential applications are multiple: from low-cost commercial to high impact scientific systems, to mass-market and on board cameras, defense and security, and astronomical community. We describe here the first concave curved CMOS detector developed within a collaboration between CNRS-LAM and CEA-LETI. This fully-functional detector 20Mpix (CMOSIS CMV20000) has been curved down to a radius of R_c =150mm over a size of 24x32mm^2. We present here the methodology adopted for its characterization and describe in detail all the results obtained. We also discuss the main components of noise, such as the readout noise, the fixed pattern noise and the dark current. Finally we provide a comparison with the at version of the same sensor in order to establish the impact of the curving process on the main characteristics of the sensor

Curved CMOS sensor: characterization of the first fully functional prototype

Many are the optical designs that generate curved focal planes for which field flattener must be implemented. This generally implies the use of more optical elements and a consequent loss of throughput and performances. With the recent development of curved sensor this can be avoided. This new technology has been gathering more and more attention from a very broad community, as the potential applications are multiple: from low-cost commercial to high impact scientific systems, to mass-market and on board cameras, defense and security, and astronomical community. We describe here the first concave curved CMOS detector developed within a collaboration between CNRS-LAM and CEA-LETI. This fully-functional detector 20Mpix (CMOSIS CMV20000) has been curved down to a radius of R_c =150mm over a size of 24x32mm^2. We present here the methodology adopted for its characterization and describe in detail all the results obtained. We also discuss the main components of noise, such as the readout noise, the fixed pattern noise and the dark current. Finally we provide a comparison with the at version of the same sensor in order to establish the impact of the curving process on the main characteristics of the sensor

Numerical simulation and experimental characterization of c-Si cells mechanical limits in spherical curvature shape

International audienceTo ensure the mechanical strength of the cells in shaped photovoltaic modules, it is important to know their double bending radius limit, as well as their mechanical breaking limits.This study focuses on the mechanical characterization of Si cells under double curvature load. It aims at determining the mechanical limits of silicon under double curvature, as well as the minimum radii of curvature reachable without breaking the cell.A numerical model representing the curvature of a cell in a double-curvature wedge has been implemented. It aims at predicting, for a given cell thickness, the acceptable double radius limit. This numerical model is validated with experimental tests to quantify the mechanical limits of silicon under double curvature. Experimental tests were performed on different types of cells -wafers, cells with or without interconnections- to evaluate the impact of each process step on the mechanical strength of cells under this double curvature load

Curved sensors for compact high-resolution wide field designs: prototype demonstration and optical characterization

International audienceOver the recent years, a huge interest has grown for curved electronics, particularly for opto-electronics systems. Curved sensors help the correction of off-axis aberrations, such as Petzval Field Curvature, astigmatism, and bring significant optical and size benefits for imaging systems. In this paper, we first describe advantages of curved sensor and associated packaging process applied on a 1/1.8'' format 1.3Mpx global shutter CMOS sensor (Teledyne EV76C560) into its standard ceramic package with a spherical radius of curvature Rc=65mm and 55mm. The mechanical limits of the die are discussed (Finite Element Modelling and experimental), and electro-optical performances are investigated. Then, based on the monocentric optical architecture, we proposed a new design, compact and with a high resolution, developed specifically for a curved image sensor including optical optimization, tolerances, assembly and optical tests. Finally, a functional prototype is presented through a benchmark approach and compared to an existing standard optical system with same performances and a x2.5 reduction of length. The finality of this work was a functional prototype demonstration on the CEA-LETI during Photonics West 2018 conference. All these experiments and optical results demonstrate the feasibility and high performances of systems with curved sensors

A methodology to design optical systems with curved sensors

International audienceCurved sensors are a suitable technological solution to enhance the vast majority of optical systems. In this work, we show the entire process to create curved sensor-based optical systems and the possibilities they offer. This paper defines the boundaries of the reachable curvatures for a full range of monolithic sensors. We discuss how the curved focal plane shape is related to the imaged scenes and optical parameters. Two camera prototypes are designed, realized and tested, demonstrating a new compact optical architecture for a 40 degree compact objective, as well as a wide field fisheye zoom objective using a convex sensor to image a 180 degree field of view

Methodology to design optical systems with curved sensors

Curved sensors are a suitable technological solution to enhance the vast majority of optical systems. In this work, we show the entire process to create curved sensor-based optical systems and the possibilities they offer. This paper defines the boundaries of the reachable curvatures for a full range of monolithic sensors. We discuss how the curved focal plane shape is related to the imaged scenes and optical parameters. Two camera prototypes are designed, realized, and tested, demonstrating a new compact optical architecture for a 40 deg compact objective as well as a wide-field fisheye zoom objective using a convex sensor to image a 180 deg field of view

Curved detectors for astronomical applications: characterization results on different samples

International audienceDue to the increasing dimension, complexity and cost of the future astronomical surveys, new technologies enabling more compact and simpler systems are required. The development of curved detectors allows to enhance the performances of the optical system used (telescope or astronomical instrument), while keeping the system more compact. We describe here a set of five curved CMOS detectors developed within a collaboration between CEA-LETI and CNRS-LAM. These fully-functional detectors 20 Mpix (CMOSIS CMV20000) have been curved to different radii of curvature and spherical shapes (both convex and concave) over a size of 24x32 mm 2. Before being able to use them for astronomical observations, we assess the impact of the curving process on their performances. We perform a full electro-optical characterization of the curved detectors, by measuring the gain, the full well capacity, the dynamic-range and the noise properties, such as dark current, readout noise, pixel-relative-non-uniformity. We repeat the same process for the flat version of the same CMOS sensor, as a reference for comparison. We find no significant difference among most of the characterization values of the curved and flat samples. We obtain values of readout noise of 10e − for the curved samples compared to the 11e − of the flat sample, which provides slightly larger dynamic ranges for the curved detectors. Additionally we measure consistently smaller values of dark current compared to the flat CMOS sensor. The curving process for the prototypes shown in this paper does not significantly impact the performances of the detectors. These results represent the first step towards their astronomical implementation

Curved detectors developments and characterization: application to astronomical instruments

International audienceMany astronomical optical systems have the disadvantage of generating curved focal planes requiring flattening optical elements to project the corrected image on flat detectors. The use of these designs in combination with a classical flat sensor implies an overall degradation of throughput and system performances to obtain the proper corrected image. With the recent development of curved sensor this can be avoided. This new technology has been gathering more and more attention from a very broad community, as the potential applications are multiple: from low-cost commercial to high impact scientific systems, to mass-market and on board cameras, defense and security, and astronomical community. We describe here the first concave curved CMOS detector developed within a collaboration between CNRS-LAM and CEA-LETI. This fully-functional detector 20 Mpix (CMOSIS CMV20000) has been curved down to a radius of $R_c$ =150 mm over a size of 24x32 mm$^2$. We present here the methodology adopted for its characterization and describe in detail all the results obtained. We also discuss the main components of noise, such as the readout noise, the fixed pattern noise and the dark current. Finally we provide a comparison with the flat version of the same sensor in order to establish the impact of the curving process on the main characteristics of the sensor

Meeting report of the 4th biennial Metabolism and Cancer symposium

International audienc