DE19649736A1 - Sun simulation installation with elliptical mirror element - Google Patents

Abstract

The sun simulator simulates the sun with respect to its geometry and extra-terrestrial radiation intensity on a circular ray cross-section of approx. 200 mm diameter. The simulator is arranged in a casing and includes a standing xenon high-pressure lamp in a first focus of an elliptical mirror element and a blind in the second focus of the same. A lens is arranged in such way, that the sun blind and therefore the second focus of the mirror element are found in its focal plane. A spherical mirror reflects the xenon lamp head-down on itself. An adjustable blind can be exchanged with the sun blind, and enables a fine adjustment of the optical components of the simulator in the cold and in the warm condition.

Description

1. Technical description 1.1 Structure of the simulator

The sun simulator generates a circular beam Cross-section of about 200 mm in diameter, the respect Irradiance (1 solar constant = 135 mW / cm2 extraterres tric) uniformity, spectral distribution (visible to near infrared (380 nm to approx. 1100 nm) and collimation angle (32 arcmin ± 0.2 arcmin) is approximated to solar radiation.

The system consists of the following modules:

• - Simulator (sketch No. 1) with lamp ( 1 ), ignitor ( 2 ) and optical components ( 3 , 4 , 5 , 6 )
• - ballast
• - Connection cable
• - Luminous flux control device
• - Suction device for forced cooling of the lamp

1.2 Optical system

The optical system is shown in sketch No. 2. It consists of the following components:

• - spherical mirror ( 1 )
• - Xenon short arc lamp ( 2 )
• - extra-axial ellipsoid mirror ( 3 )
• - cover ( 4 )
• - lens (achromatic) ( 5 )
• - spectral adjustment filter ( 6 )

The xenon short-arc lamp is arranged upright. The plasma There is an arc between their two electrodes in the center of curvature of the spherical mirror and on the other hand in 1. Focal point of the ellipsoid mirror. Through the spherical mirror the arc is displayed upside down in itself, which creates a more uniform luminance of the arc image is reached on the bezel. The ellipsoid mirror focuses the radiation emitted by the xenon lamp in its second lamp point at which the aperture is also arranged.

The aperture is on the other hand in the focal plane of the follow the objective. All di starting from a point of the aperture emitted rays run parallel behind the lens.  

The diameter of the aperture is the focal length of the lens adjusted so that all exiting behind the lens Parallel bundle within a cone with an opening angle of 32 arc minutes.

This is the same angle at which, in quasi Sun at infinite distance in the sky, the earthly one Observer appears.

The adjustment filter attached to the outside of the lens has the Task, the spectral distribution of the simulated radiation Adjust the sun spectrum as well as possible.

In particular, emission maxima of the Xe lamp must be between 800 nm and 840 nm and between 860 nm and 1000 nm can be attenuated.

By using the exception made of aluminum the axial ellipsoid mirror segment (metal optics) Simulator particularly compact.

Luminous flux control:
A photocell, which dips into the simulator output beam, measures the luminous flux and keeps it constant via a control circuit in the ballast by regulating the lamp current to an adjustable value.

1.3 Power supply

A primary clocked mains ballast is used for the power supply device with integrated luminous flux control. Any one Current between 0 and 160 amps can be set on the device will.

1.4 Mechanical interfaces

In the floor of the lamp house are near the Simulator focus two bolt circles for fastening the Simulator on a tripod.

In addition, there are three feet in the base plate of the lamp house with pendulum support screwed onto the simulator on one Table can be set down.

To access the adjustment located in the base plate To ensure screws, the installation must be sufficient Height above the table.

On the top of the lamp house, just above the lamp, is a suction nozzle attached. This must have a flexible Hose of 200 mm diameter an extraction system for forced Cooling of the lamp can be connected. The suction power must be so high that the wind speed at the lamp equator in 5 mm distance is at least 5 m / sec. In this case ensures that the maximum permissible base temperature of the Lamp does not exceed 230 ° C.

The extracted air is due to a special coating of the Lamp bulb low in ozone.  

1.5 Adjustment elements and adjustment procedures 1.5.1 Adjustment elements

• 1. The lens is relative to the aperture in the axial direction adjustable.
• 2. The aperture can also be in the axial direction relative to Objective and to be adjusted to the ellipsoid mirror.
• 3. The ellipsoid mirror holder contains one translation each adjusters in the lateral and axial direction as well as two Rotation adjuster around two perpendicular to the simulator axis lying axes.
• 4. Together with the lamp holder, the lamp can be adjusted tilted around two horizontal axes and additionally in verti cal direction are shifted.
• 5. The spherical mirror holder contains one translation each adjuster in the lateral and axial direction as well as a Rotation adjuster around a vertical axis. The whole Bracket can also be tilted around two horizontal axes and also be moved in the vertical direction.

All adjustment devices mentioned are closed Lamp house accessible from the outside. The operation takes place ent neither from the base plate nor through small openings in the walls of the lamp house, which are covered with flaps.

1.5.2 Adjustment procedure

After mechanical pre-adjustment of the optical components with the help of Reference marks, there is an internal fine adjustment of the simulator when cold, d. H. with lamp switched off, with open Casing.

This cold "fine adjustment" is followed by a warm "fine adjustment" closed housing with movements of the optical components through the small, coverable openings in the walls of the Simulator housing or by adjusting screws in the Base plate of the simulator can be accomplished.

For the cold fine adjustment instead of the original sun visor uses a special adjustment panel. This enables, despite same aperture and position an observation of the environment the aperture level, which - with correct adjustment - with the Image plane of the ellipsoid is identical.

The aperture level can now be changed using the simulator lens Eye or with a video camera, as if magnified by a magnifying glass to be viewed as.

This makes it possible for both the ellipsoid mirror cast image of the lamp cathode as well as that of the spherical Mirror-designed upside down cathode image to adjust that both come to lie just outside the edge of the aperture.

Also the positioning of the lamp image in the axial direction so that the lamp pictures are in the aperture plane, can with With the help of the adjustment panel.  

In this case, the lamp image must be moved back and forth or Moving the eye up or down or the video camera in front of the Simulator lens in the same location relative to the aperture stay.

After closing the lamp house, a first warm one can now Fine adjustment - still with the adjustment panel. For this purpose, the two arcing pictures, which are from Ellipsoid mirror and designed from the spherical rear-view mirror are observed with the help of strong gray filters.

The setting criteria are the position of the aperture near the Lamp cathode and freedom from vignetting throughout Output beam.

Then the adjustment panel is pushed out against the sun visor swaps. The last fine adjustment is now carried out using a Photo cell that is moved in the simulator beam so that a Light distribution as uniform as possible over the beam cross-section division is achieved.

Claims (1)

Sun simulator for simulating the sun with regard to geometry and extraterrestrial irradiance on a circular beam cross section of approx. 200 mm in diameter in a housing

• - With a standing xenon high-pressure lamp in the first focal point of an extra-axial ellipsoid mirror segment and an aperture in the second focal point of the same
• - With a lens (achromatic), arranged such that the sun visor and thus the second focal point of the ellipsoid mirror are in its focal plane
• - With a spherical mirror (rearview mirror), which shows the xenon lamp upside down in itself
• - With an adjustment panel that can be exchanged for the sun visor and with which, according to the above method using the simulator lens as a magnifying glass, fine adjustment of the optical components of the simulator is possible in the cold and in the warm state.