System and method for checking the aim of a vehicle headlamp

Abstract

A system and method for checking the aim of the high and low beams of a vehicle headlamp are provided. The system comprises a vehicle position locator adapted to be centered under the vehicle, and a target screen located at a predetermined distance from the headlamp of a vehicle centered on the locator. A laser/prism subassembly is mounted to the locator for lateral and vertical movement relative to the vehicle. The prism directs the laser beam toward the headlamp when it is positioned in front of the laser. A plurality of photosensors on the target screen sense the intensity of a light beam from the headlamp, and meters on the target screen indicate comparisons of the levels of intensity of portions of the beam sensed by the individual photosensors. The method comprises the steps of directing the laser beam at the center of the headlamp lens with the prism, fixing the position of the laser with respect to the headlamp lens, and moving the prism to redirect the laser beam at the target screen to establish an origin point for a properly aimed headlamp. The vehicle headlamp is then shined upon the photosensors. If the headlamp beam intensities sensed by the photosensors have the proper comparative distribution, the meters will verify the proper aim of the headlamp. If not, the target screen is moved until the meters show an acceptable aim indication. The steps of directing the laser light beam at the center of the headlamp lens, fixing the laser position, and redirecting the laser light beam at the target screen are then repeated. The distance on the screen between the origin point and the location of the laser beam after moving the screen indicates the amount of headlamp misalignment. The headlamp is accepted only if this distance is within prescribed limits.