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Exposure Control Instruments for Large Area Illuminators

Exposure Control Instruments for Large Area Illuminators
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Exposure Control Instruments for Large Area Illuminators - 1

208 Phone: 1-800-222-6440 • Fax: 1-949-253-1680 L i g h t S o u r c e s TECHNICAL REFERENCE MONOCHROMATOR AND INCANDESCENT SOURCES ARC SOURCES DEUTERIUM SOURCES CALIBRATION SOURCES FIBER ILLUMINATORS PHOTOLITHOGRAPHY SOLAR SIMULATORS INSTRUMENTS ACCESSORIES FOR ORIEL LIGHT SOURCES Exposure Control Instruments for Oriel Large Area Illuminators 68951 Digital Exposure Controller and 69920 1000 W Solar Simulator Power Supply The 68951 Digital Exposure Controller is a light intensity controller and digital timer in one package. It maintains a constant light level and allows preset timed or dosage based exposure control. For those not requiring a light intensity controller or dose control, we offer a stand-alone digital timer, model 68945. Both instruments may be controlled via a PC through an RS-232 interface. The 68951 and 68945 support our Large Area Illuminators, Solar Simulators and Flood Exposure Sources. For light intensity control instruments for our small area illuminators, see page 226. Digital Exposure Controller Our sources have highly regulated power supplies to operate the lamps at constant power or current. However, with aging of the lamp and variables such as electrode erosion, gas absorption or desorption, the light output can change. These changes tend to be wavelength dependent. The 68951 Digital Exposure Controller works with the power supply to compensate for these changes and ensure a stable, long-term output. See Fig. 1 for an example of the effect of the 68951 on the light output of a kW Solar Simulator. TIME (HOURS) WITH 68951 WITHOUT 68951 OUTPUT (% OF MEAN) 98.8 100.0 99.0 100.2 99.2 100.4 99.4 100.6 99.6 100.8 99.8 101.0 0 2 4 6 810 12141618 20 22 24 26 28 30 32 Fig. 1 The effect of the 68951 Digital Exposure Controller on the output of a 1000 W Solar Simulator. How it Works The 68951 is made up of a light sensing head, a controller, and a fiber optic probe. The silicon based light sensor monitors part of the light source output (via the fiber probe), and the controller constantly compares the recorded signal to the set level and changes the power supply output accordingly to keep the measured signal at the set level. Automatic detector gain setting allows the unit to work with 300 to 1600 W Large Area Illuminators. Built-in Digital Timer The 68951 also allows timed exposures. The 68951 is capable of exposure times from 10 ms to 9999 hours, in increments as short as 10 ms. However, the mechanical response time of the shutter in our Solar Simulators limits the minimum exposure time to 100 ms, and the shortest interval between exposure to 80 ms. For those instances when a timed exposure is not sufficient, you can use the auto-dose mode to keep the shutter open until the total flux equals a user set value. Stand-Alone Digital Timer If timed exposures are required without the need for ultra constant light output, purchase the 68945 Digital Timer. Just like with the 68951 Digital Exposure Controller, the 68945 Digital Timer allows exposure dosages from 10 ms to 9999 hours, in 0.1 second intervals. Note: the Illuminators’ mechanical shutter limits the exposure times to 100 ms, and the shortest interval to 80 ms. • Reduce long and short term variations in lamp output • Ensure accurate timed exposures • Dose control • RS-232 communications • Works with Oriel Solar Simulators and Flood Exposure Sources SOLAR SIMULATOR HOUSING PROBE ASSEMBLY Fig. 2 Diagram showing the probe assembly from the 68951 Digital Exposure Controller, mounted to a Solar Simulator Housing.

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