Excelitas Technologies provides innovative, customised optoelectronics and advanced electronic systems to a global customer base of leading OEMs seeking high-performance, market-driven technology solutions. They are committed to enabling OEM customers' success in their markets and applications.
Infrared Emitting Diodes (IRED) are typically used in conjunction with Excelitas detectors to form a sensing system. IREDs with wavelengths 770 nm, 870 nm 880 nm, 940 nm, and 950 nm are offered for applications like Smoke Detection, Encoders, Transmissive and Reflective Optoswitches.
LEDs are solid state p-n junction devices which emit light when forward biased. An LED is a Light Emitting Diode, a generic term. An IRED is an Infrared Emitting Diode, a term specifically applied to Excelitas IR emitters. Unlike incandescent lamps which emit light over a very broad range of wavelengths, LEDs emit light over such a narrow bandwidth that they appear to be emitting a single "colour". Their small size, long operating lifetimes, low power consumption, compatibility with solid state drive circuitry, and relatively low cost, make LEDs the preferred light source in many applications.[ Send Enquiry ]
A laser diode is a laser where the active medium is a semiconductor similar to that found in a light-emitting diode. The most common and practical type of laser diode is formed from a p-n junction and powered by injected electric current. The laser cavity has mirrors at each end to reflect back and forth photons to create an amplification effect when the waves are in phase. At certain frequencies a stable standing wave pattern is formed. At these frequencies the cavity is in resonance, and the oscillation can be sustained with minimum losses.
At resonance, an integral number of half wavelengths of the resonating wavelength of the resonating wave must fit into the light of the cavity:
L = mλ/2
L = length of the cavity (m)
m = an integral
λ =wavelength of the resonating frequency (m)
Pulsed semiconductor lasers in the near IR (NIR) are commonly used for long distance time-of-flight or phase-shift range finding systems. Warsash Scientific offer a broad range of suited pulsed 905 nm lasers including monolithic layered structures with up to 4 active areas per chip, resulting in up to 100 Watts of peak output power.[ Send Enquiry ]
SmartBlue™ digital linescan cameras incorporate the latest in photodiode array technology based on the industry standard Reticon® devices with state of the art electronics and a robust industrial camera housing. The linescan photodiode array is a Pinned Photodiode Charge Couple Device which allows for high sensitivity, fast readout, while maintaining high dynamic range, and low image lag.
SmartBlue™ cameras are cost effective high performance digital linescan cameras, and feature a CameraLink™ digital interface. These cameras feature geometrically precise photodiode CCD image sensor with 14 um square pixels with a resolution of 2048 pixels. This "next generation" array can achieve data rates up to 80 MHz with superior noise immunity, precise linearity, and high CTE.
They are designed for high line rate applications with low to moderate light conditions and where small size, and low cost are required.
The two-point Flat Field pixel correction circuits give the user the flexibility of correcting video data to compensate for non-uniformities in lighting, lens, or CCD sensor variations. Adjustable gain and offset controls allow users to compensate for variations in illumination found in the "real-world" applications.
The robust design in conjunction with ultra-modern manufacturing techniques allows the SmartBlue™ camera to deliver consistent, reliable performance while the rugged industrial design metal housing provides the maximum protection in a variety of harsh environments and factory floor conditions.[ Send Enquiry ]
Warsash Scientific offer an improved version of the industry standard P-series -712 linear array, the -012. The -012 version represents the latest in CCD technology. Users can expect increased sensitivity and efficiency in all specified wavelengths, increased capacity to collect, store, and transfer data, lower noise across the imager, all the while consuming significantly less power and in a pin-compatible configuration with their existing -712 P-series sockets.
A charge-coupled device (CCD) is a device for the movement of electrical charge, usually from within the device to an area where the charge can be manipulated, for example conversion into a digital value. This is achieved by "shifting" the signals between stages within the device one at a time. Technically, CCDs are implemented as shift registers that move charge between capacitive bins in the device, with the shift allowing for the transfer of charge between bins.[ Send Enquiry ]
These photodiode arrays are used to generate an X-ray image by scanning an object line by line. The X-rays are converted into light through the attached scintillator crystal. The light intensity is then measured by the photodiodes. The boards are employing chip-on-board technology with optically adapted scintillator crystals. The listed designs can be ordered as a standard part, but can also be customised to meet the needs of a wide variety of applications.
Custom photodiode arrays give customers the option to choose the:
First stage amplification electronics can also be added to the custom board design to convert the current generated by the photodiode into an easy to measure voltage.[ Send Enquiry ]
These arrays include detectors composed of several thermocouples typically connected in series. They are DC-type detectors and, thus, best suited for non-contact temperature measurement. These thermopile modules are based on silicon micromachining technology. A special IR-absorption layer covers the hot junctions, creating the sensor's sensitive area.
Thermopile linear arrays with digital interface consist of a thermopile line/matrix array sensor with integrated ASIC, E2PROM, a microcontroller with integrated 10-bit analogue-to digital converter for signal processing and interfacing.
The microcontroller controls the multiplexer of the thermopile line/matrix sensor as well as all internal operations. These include measurements and calculations for the object, ambient temperatures and post-processing of the temperatures to output them via a digital serial interface (SMBus). The temperature-dependant signal of the thermopile line array elements is subsequently fed through an analogue-input multiplexer into a low noise, low offset chopper amplifier with constant gain. The amplified thermopile signal, a voltage reference signal and the signal from the on-chip integrated PTAT (ambient temperature) sensor is connected to an output multiplexer which alternately feeds the signals to the analogue digital converter (ADC) of the microcontroller.
After analogue-to-digital conversion, the resulting digitised voltage signals are stored in the microcontroller's RAM. Based on the calibration settings stored in the TPLM's E2PROM and on the described measurement results, ambient temperature voltage signal (VTamb) and normalised voltage signals for individual pixels (Pi) are calculated from the raw signals.
An SMBus-compatible, two wire bidirectional serial interface is provided to read out the sensor's temperature signals and for Read/Write access to the sensor's configuration data and calibration parameters. The SMBUS allows connection of a master device (MD) and one or more slave devices (SD).
Warsash Scientific offer instrumentation for:
An Avalanche Photodiode (APD) provides higher sensitivity than a standard photodiode. It is ideal for extreme low-level light (LLL) detection and photon counting. Offered in Silicon or InGaAs materials, these devices provide detectivity from 400 nm - 1100 nm. Multiple configurations are available to provide a wide range of sensitivity and speed options.
The use of APDs instead of PIN Photodetectors will result in improved sensitivity in many applications. In general, APDs are useful in applications where the noise of the amplifier is high — i.e., much higher than the noise in the PIN Photodetector. Thus, although an APD is always noisier than the equivalent PIN, improved signal-to-noise can be achieved in the system for APD gains up to the point where the noise of the APD is comparable to that of the amplifier.
For example, when the system bandwidth is high, the amplifier noise is high, and an APD is likely to be useful. On the other hand, in very low bandwidth systems, the noise of the amplifier is likely to be very low, in which case, the APD may not be the best choice. In applications where the background optical power falling on the detector is very high, such as operation of the detector in daylight conditions with little or no filtering, an APD may not be useful, except perhaps at low gain, since the multiplied noise of the background illumination will be very high and may exceed that of the amplifier.
Products offered include:
Excelitas utilises Silicon and InGaAs materials for their photodiodes to provide detection from 220nm to 1700nm. These devices are offered in a variety of sizes to meet customer sensitivity and speed requirements.
Phototransistors are examples of photodiode-amplifier combinations integrated within a single silicon chip.
Photodiodes are unique among light detectors in that when illuminated, they generate an output which is proportional to light level. They are solid state light detector that consists of a shallow diffused P-N junction with connections provided to the outside world. When the top surface is illuminated, photons of light penetrate into the silicon to a depth determined by the photon energy and are absorbed by the silicon generating electron-hole pairs. The electron-hole pairs are free to diffuse (or wander) throughout the bulk of the photodiode until they recombine. The average time before recombination is the "minority carrier lifetime".
Phototransistors are solid state light detectors that possess internal gain. This makes them much more sensitive than photodiodes of comparably sized area. These devices can be used to provide either an analogue or digital output signal. The phototransistor can be viewed as a photodiode whose output photocurrent is fed into the base of a conventional small signal transistor. While not required for operation of the device as a Photodetector, a base connection is often provided allowing the designer the option of using base current to bias the transistor. The typical gain of a phototransistor can range from 100 to over 1500.
Warsash Scientific offer instrumentation for:
Photon counting at certain wavelengths in the UV, visible and near-IR range is one of the key technologies in today's fast-growing analytical instrumentation, diagnostics, and scientific applications space.
These Single Photon Counting Modules (SPCMs) are self-contained modules that offer market-leading photon counting performance in parameters like high Photon Detection Efficiency (PDE), low after pulsing, highest uniformity over active area, high linear dynamic range, and low dark counts. This series of single photon counting modules are designed and built to be fully RoHS-compliant.
The SPCMs we offer were the first APD-operated photon counting devices on the market. They use a unique APD that was developed specifically to be operated in so-called "Geiger-mode", which means operated above breakdown voltage, so that a single incoming photon triggers an avalanche of electrons already large enough to be detected and counted as an electronic pulse. The SPCM uses a unique silicon avalanche photodiode (SliKTM) with a circular active area intended for peak photon detection efficiency. The photodiode is both thermoelectrically-cooled and temperature-controlled, ensuring stabilised performance despite ambient temperature changes.[ Send Enquiry ]
The analogue optical isolator (AOI) uses an optical link between input and output. The input element is an LED and the output element is a photoconductive cell or simply photocell. Together, the coupled pair acts as an electrically variable potentiometer. Since the output element of the AOI is a resistor, the voltage applied to this output resistor may be DC and/or AC and the magnitude may be as low as zero or as high as the maximum voltage rating. Because the input will control the magnitude of a complex waveform in a proportional manner, this type of isolator is an analogue control element. AOIs may be used in the ON-OFF mode but the fastest response time is in the millisecond range. A level sensitive Schmitt trigger is required between the AOI and logic gates when used in digital circuits.
Optoswitches are ideal for non-contact sensing applications. They consist in an emitter and a detector integrated in a plastic housing. The emitter is an IR LED while the detector is either a phototransistor or a photodarlington. These optoswitches are available either in transmissive or reflective configuration.
In its most basic form, a reflective optical switch (retro) consists of a housing which holds both a light source and a detector. Light from the lamp of LED radiates outward and is reflected back should an object be placed in front of the switch. The reflected light is sensed by the Photodetector whose output signal changes accordingly.
When the object to be sensed has a polished surface, such as aluminium foil or Mylar tape, often the best type of reflective switch to use is one which is designed to take advantage of the large amount of directly reflected light. This is done by mounting the emitter and detector such that their optical centres lie along the legs of an isosceles triangle such that the angle of the incidence of the emitter is equal to the angle of reflection.
When trying to sense matte objects (which do not have a highly polished surface, such as white paper), it is often possible to use a type of reflective switch optimised for sensing diffuse reflected light. Such devices have the emitter and detector mounted parallel to each other within the switch housing.[ Send Enquiry ]
The Photocell Light-Dependent Resistor can provide a very economical and technically superior solution for many applications where the presence or absence of light is sensed (digital operation) or where the intensity of light needs to be measured (analogue operation).
Semiconductor light detectors can be divided into two major categories: junction and bulk-effect devices. The bulk-effect photoconductors have no junction. The bulk resistivity decreases with increasing illumination, allowing more photocurrent to flow. This resistive characteristic gives bulk-effect photoconductors a unique quality: signal current from the detector can be varied over a wide range by adjusting the applied voltage.
To clearly make this distinction, we refer to photoconductors as photoconductive cells or, simply, "Photocells". Photocells are thin-film devices made by depositing a layer of a photoconductive material on a ceramic substrate.
Warsash Scientific offer a wide range of Pyroelectric Detectors in Single Element, Dual Element and Quad Element designs. To satisfy a broad range of applications, we provide various element geometries, filters and housings.
With the addition of the new DigiPyro® Family, setting the standard in digital motion and presence detection, we have successfully begun helping our customers convert analogue detectors to digital. The latest DigiPyro innovations include the "Smart" DigiPyro, for integrated motion electronic circuitry. Our clients are not limited to off-the-shelf designs; customised designs are also possible.
For a standard Dual Element Detector, the signals are in the range of 3000 V/W. That means the infrared radiation of a person moving at a speed of 1m/s with a distance of 10m from the detector generates a signal of some mV. Output signals can be analogue as well as digital.
Pyroelectric Detectors utilise the "Pyroelectric Effect" for non-contact radiation measurement. Several types of crystals create charges on the surface, induced by temperature changes in the material that cause a change in the polarisation of the sensor material. Whenever a change occurs in the radiation that is absorbed on the top surface of the sensitive material, the temperature of the material changes and the Pyroelectric Detector generates a signal. Using an IR filter allows one to select the sensitive wavelength range. If the radiation does not change, the temperature of the crystal will reach equilibrium and the Pyroelectric Element will discharge.The Smallest Pyroelectric IR & Thermopile Surface Mount Detectors (74KB)
The DigiPile™ family of Digital Thermopiles is the latest in digital infrared sensing technology innovation and provides OEM designers with reduced space requirements on printed circuit boards, requires fewer additional components, and provides improved resistance to electromagnetic interference (EMI). The DigiPile family is offered in a range of housing and sensing areas with applications in thermometry, pyrometry, and non-contact temperature sensing.
Warsash Scientific offer a wide range of Thermopile Detectors including Single-Element, Dual- Element and Quad-Element designs. The "Element" refers to the size of the infrared absorbing surface. We offer various surfaces and housings. Our clients are not limited to off-the-shelf designs; customised designs for the most demanding applications are also possible.The Smallest Pyroelectric IR & Thermopile Surface Mount Detectors (74KB)
Warsash Scientific offer a wide range of Thermopile Modules. The modules consist of a thermopile sensor mounted on a PCB with a connector. The PCB can also provide for optional features such as voltage regulation and a noise-reduction filter. The ISO-thermal sensor concept delivers an important upgrade to the thermopile family; by utilising the unique, patented construction of the ISO-thermal sensors, we are able to offer this range of devices with improved performance, delivering substantially improved temperature measurement performance under thermal shock conditions. The ISO-thermal module includes integrated temperature compensation for a defined temperature environment and the calibration to a certain object temperature range. Modules are offered as programmed per individual customer request, and there is a range of standard versions. For requirements of defined spot sizes, we offer sensors with a field of view defined by optical apertures, internal lenses or external mirror optics.
A temperature reference output is included. Upon request, the thermopile modules can also be supplied as calibrated modules but without internal temperature compensation. In this case the customer will do the temperature compensation externally with the use of the supplied reference output.
Thermopile detectors are composed of several thermocouples typically connected in series or, less commonly, in parallel. They are DC-type detectors and, thus, best suited for non-contact temperature measurement. These thermopile sensors are based on silicon micromachining technology. A special IR-absorption layer covers the hot junctions creating the sensor's sensitive area. The output of a thermopile is usually in the range of tens or hundreds of millivolts. In addition to increasing the signal level, the device may be used to provide spatial temperature averaging.
Thermopiles do not measure the absolute temperature, but generate an output voltage proportional to a local temperature difference or temperature gradient. Thermopiles are the key component of the infrared thermometers that are widely used by medical professionals to measure body temperature via the ear.[ Send Enquiry ]