WELCOME    HOMEPAGE     INTRODUCTION    PRODUCTS    INTERNATIONAL LINKS    HOURAI ORCHID

PAGE-1     PAGE-2     PAGE-4     PAGE-5     PAGE-6

LAMP PHOTOMETRIC SYSTEM

The Compact photometric system operates on the same basis as LSI's large mirror goniophotometers, collecting intensity data at all horizontal and vertical angles.  As a further option, the system is available with a CCD Video Camera attachment, which allows the production of luminance maps of the actual arc streams and filaments.  This provides complete evaluation of a lamp's photometric characteristics.

State-of-the-art photo-detectors and computer hardware, coupled with sophisticated data collection software, provide a fully automated test system for lamp manufacturers and optical system designers.

Description

The Lamp Photometric system consists of three basic systems plus software, and one optional system.  Together, these can perform intensity (candlepower) measurement and luminance mapping for all directions, without movement of the lamp.  Thus the system is suitable for the photometry of metal halide lamps and other orientation-sensitive types.

A small mirror rotates around the test item, cutting a complete vertical plane.  Light collected by the mirror reflects to the photo-detector, which is mounted on the mirror arm and thus rotates with the mirror.

The entire mirror and photo-detector assembly is mounted on a precision turntable, which provides horizontal rotation.  Thus the mirror is able to perform its vertical sweep at any horizontal angle, allowing full data collection.

Mechanical System

All structure members consist of precision rails and brackets.  These are mounted to the vertical and horizontal drive systems, using highest accuracy digital stepping motors.  The motors are rated 0.001° resolution, 0.01° accuracy.

The digital motors used in the photometer have no gears or other drive systems, which can introduce backlash in time.  LSI uses direct drive motors so that complete reliability is provided for the life of the equipment.

angle sensing feedback transmitters are contained within the motor drive systems.  These provide independent position verification.  Thus when a motor rotates under the computer command and reaches its position as instructed, the feedback transmitters confirm to the computer that in fact the correct position has been reached.  This provides unparallel accuracy.

Photo-detector and Electronics

The Photo-detector used for intensity measurements is a high stability, low noise silicon cell.  It is equipped with a very high accuracy spectral correction filter (F1',1.5%), giving precise measurement even on the most complex discharge sources.

A unique electronic system oversees the photo-detector's response activity and automatically adjusts the system sensitivity (i.e. gain) up or down to achieve the highest possible accuracy.  Even with the mirror traveling at its maximum speed, this 'signal Maximizer" circuitry makes decisions 'on the fly' so that the optimum amplifier gain is set for each intensity reading being recorded.

The Signal Maximizer circuitry also automatically compensates for what is termed 'dark current' - a signal generated by the electronics even when there is no light on the photocell.  This signal varies from one gain setting to the next, and if not properly accounted for, can create serious test results errors.  Dark current values are automatically measured and applied to each gain stage throughout the test sequence without the need for operator input.

Detailed Specifications could be obtained upon request.