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Lasers, Optics and Imaging Technologies
The use of light emitting and detecting components in medical devices has long since been adapted for diagnostics, analysis devices, and more recently in treatment, surgical, imaging and DNA sequencing equipment. The advancement of medical science and opto-electronics has led to increased utilization of light emitting sources and detectors. Projections for use of such components continues to grow with further advancements in both fields. Optical technologies such as lasers, LEDs, lens assemblies, cameras, and other sensors are used in many medical devices for therapies (ablation, cautery, skin treatments), endoscopy, in-vivo diagnostics (eye exams, cancer detection, etc.), and for in-vitro diagnostics (chemistry, cytometry, immunoassay).
DeviceLab leverages the vast experience with opto-electronics and optical design to provide comprehensive product design and commercialization of medical devices utilizing these technologies.
Lasers emit coherent light resulting in very tight focus. They can also have high temporal coherence, which allows them to emit light with a very narrow spectrum or a single color of light. Implementation of laser technology is not trivial. Proper modeling is critical to predicting the effects of diffraction, interference and laser light back focusing. Each artifact must be understood and accounted for to safely and properly incorporate laser technology into a medical device. Furthermore, modeling is required to predict the laser intensity distribution on the target. DeviceLab utilizes state-of-the art raytracing software to effectively model proposed optical systems. This lends itself to lower development cost, schedule impact and latent system issues due to optical design deficiencies.
The miniaturization of laser emitting sources, like laser diodes, has broadened the medical device applications into smaller instruments and handpieces. The design of handpieces incorporating lasers presents unique safety and human factors to be considered during product design. DeviceLab has the expertise in addressing these concerns when utilizing lasers in a medical device.
LED and other light sources
Early medical devices employed incandescent light sources such as halogen lamps, or high intensity discharge lamps, such as xenon, for sample excitation and other applications. These lamps emit a broad spectrum requiring expense optical components, such as narrow band optical filters, are not stable and have a short use life. The advancements in LED (light emitting diode) technology has facilitated simpler, less expensive and superior designs. LED has a relatively narrow spectrum emission, longer life, and offer a more stable intensity and control through regulated constant current and feedback. High intensity LED are now readily available but require more thermal management. Outside the visible light spectrum, ultra-violet (UV), near infrared (NIR) and infrared (IR) LED are available.
These advancements has allows the use of LED in medical device applications:
- Pulse Oximetry
- Photodynamic therapy
- Surgical and Exam Lighting
- Capillary Electrophoresis
- Skin and Cosmetic Treatment
DeviceLab has used LED technology for decades. We have successfully developed systems using a single LED , hundreds of LED, and even up to 30,000 LED. DeviceLab continuously reviews the latest technologies to leverage in the medical device product development for cost, performance, features and superior design. We have experience with broad spectrum emission source, such as the previous mentioned halogen and xenon lamps but find the applications for these older technologies to be on the decline with advancement in light emitting technologies.
Light detectors are often used in tandem with light sources to complete the optical signal path and facilitate a qualitative or quantitative analysis. Detectors are also commonly used to monitor light source output either for reference or in a control loop to regulate the source output. Relatively complex detectors are used for imaging applications.
The most common detector is the silicon photodiode. Photodiodes create an electrical current proportional to the intensity of light incident on the photo-sensitive area. Photodiodes do not discriminate light wavelength. Optical filters must be used with these sensors for discrete wavelength detection. These sensors are suitable for a wide variety of medical device and analytical instrument applications.
Linear arrays are sensors with many photodiodes arranged in a linear alignment. These sensors are used in spectroscopic analyzers with wavelength separating optic components, like prisms. These sensors can also be used in scanners and position sensing applications.
Photomultipler tubes (PMT) are used in applications to detect ultra-low light signals. A PMT is a photoemissive device that emits an electron when absorbing a photon and has an internal structure that amplifies a single electron emission into many electrons. The PMT provides a measurable electrical signal proportional to the photons collected on it’s photo sensitive electrode. Typical applications for a PMT includes, PET scanners, gamma cameras, flow cytometers, and in vitro diagnostics (fluorescence and luminescence assays).
CMOS image sensor (CIS) performance has advanced to a point where charge coupled devices (CCD) are nearly obsoleted in medical device development. These imagers have long been used in many medical imaging instruments. Their shrinking pixel size has made the sensors ideal for smaller flexible video endoscopes. CIS camera module technology in medical devices is largely driven by minimally invasive procedures. Miniature CIS modules are ideal for the smaller minimally invasive devices. CIS technology is supporting advancements in cardiovascular devices by enabling direct, real-time color imaging.
Devicelab has experience and technology expertise in developing systems with each of these sensors.
Optics design is as critical as any other aspect of a photonics based development. Device lab has an experienced optics engineering team that utilizes sophisticated software, such as Zemax, to design, develop and analyze optical systems. Devicelab has experience employing all types of lens, optical filters, mirrors, prisms, gratings and fiber optics into photonics designs. We have developed a significant number of medical devices using simple and medium to extremely complex optic systems.
Implementation of photonic technologies requires consideration of several elements by an experience cross-functional team. Mechanical, electrical, thermal, computational, chemical and material aspects must be considered for an effective photonics system. Devicelab understands these elements of photonics design and delivers robust, high performance designs. See our Services page for more detail on the technologies we employ and the Portfolio page for example projects incorporating lasers and optics.