The e9u-BGLT-20x20-B-KIT is a kit for a compact LED backlight with an integrated Siemens star on a glass substrate. It is intended as a practical test target for evaluating the resolution of lenses, cameras, and optical laboratory setups. The backlit Siemens-star pattern allows sharpness, contrast, focal-plane position, and imaging aberrations to be assessed directly in the camera image or through the optical system.

The illumination unit is installed in an enclosed housing and powered by an external battery holder for three AAA cells. This makes the product particularly suitable for quick checks on the laboratory bench, in development setups, in teaching laboratories, and in optical quality assurance.

Typical Applications

• Testing lenses, camera optics, and macro-imaging setups
• Assessing focus, sharpness, and contrast
• Comparing different lenses, apertures, or working distances
• Aligning cameras, microscope setups, and other optical systems
• Detecting edge softness, field curvature, decentration, or astigmatism
• Demonstrations and laboratory exercises on optical imaging
• Rapid functional checks of small optical setups in the laboratory

Why a Siemens star?

A Siemens star is a classic test pattern for evaluating optical systems. Its alternating bright and dark radial sectors become progressively narrower towards the centre. The radius at which the individual structures can no longer be clearly resolved provides a practical indication of the system’s resolution limit. Focus errors, target tilt, and imaging aberrations also become readily visible.

Thanks to the integrated LED backlight, no separate illumination setup is required. The test target can be quickly integrated into an optical setup and provides reproducible transmitted-light illumination.

Scope of delivery

• e9u-BGLT-20x20-B-KIT LED backlight kit
• Integrated Siemens star on a glass substrate
• Connecting cable for the battery pack
• Battery holder for three AAA cells

Batteries are not included.

Intended Use

The e9u-BGLT-20x20-B-KIT is intended exclusively for use as a backlit test target for optical resolution tests. It is used for testing, adjusting, and qualitatively evaluating lenses, cameras, and other optical setups.

This product is intended for use by qualified personnel in dry indoor environments. It must be operated only when in proper working order. It is not intended for use as general lighting, a toy, a household appliance, or a medical device.

Connection and initial operation

1. Insert three appropriate AAA batteries into the battery pack. Be sure to observe the correct polarity in the battery holder.
2. Close the battery pack cover and secure it with screws.
3. Connect the battery pack to the e9u-BGLT-20x20-B.
4. Position the module so that the plane of the Siemens star is as perpendicular as possible to the optical axis of the system under test.
5. Align the camera, lens, or optical assembly with the Siemens star.
6. Adjust the exposure or camera gain so that the bright areas are not saturated.
7. Evaluate focus and optical alignment using the image of the Siemens star.

The product must only be operated with the intended battery pack or a suitable DC power supply with a maximum voltage of 5.5 V DC. A higher supply voltage may damage the product.

Tips for Practical Use

For meaningful results, position the Siemens-star target so that its surface is flat and perpendicular to the optical axis. Even a slight tilt may cause one side of the image to appear sharper than the other. This can indicate an alignment error and should not automatically be attributed to the lens itself.

• Adjust the exposure so that the bright areas remain below saturation.
• For comparative tests, keep the distance, aperture, exposure time, and camera gain constant.
• Do not evaluate only the centre of the image; the edges often reveal additional aberrations.
• Where possible, use raw image data or reproducible camera-processing settings.
• For semi-quantitative comparisons, save the images and compare corresponding regions at the same scale.

Notes on Interpretation

If the lines near the centre of the Siemens star merge, this may have several causes, including limited optical resolution, incorrect focus, motion blur, overexposure, the sensor pixel grid, moiré or aliasing effects, and in-camera sharpening. The test target is therefore a useful tool for practical evaluation and alignment, but it does not replace a fully calibrated MTF measurement.

Safety Precautions

• This product may only be used by qualified personnel.
• Use only in dry indoor areas. Do not operate in damp conditions, where condensation may occur, or outdoors.
• Maximum supply voltage: 5.5 V DC. Connecting the device to higher voltages or unsuitable power supplies is not permitted.
• Do not stare directly at the illuminated LED surface for an extended period of time.
• The Siemens star is mounted on a glass substrate. If damaged or if the glass breaks, do not continue to use it, and do not touch any broken pieces with your bare hands.
• Do not open the housing or make any mechanical modifications to it. Modifications may compromise its protective function.
• Do not continue to use the device if there is visible damage to the case, cable, battery pack, or glass surface.

Cleaning

If necessary, the glass surface of the Siemens star can be carefully cleaned with a soft, lint-free cloth. Apply glass cleaner or isopropyl alcohol sparingly to the cloth; do not spray it directly onto the product. Do not allow any liquid to enter the housing.

Do not use abrasive cloths, harsh solvents, or mechanical tools for cleaning. Scratches or residues on the glass surface may reduce the reliability of the test results.

Storage

Store the product in a dry place, protected from dust. If the product will not be used for an extended period, remove the batteries from the battery pack to prevent damage caused by leaking batteries.

Disposal

The e9u-BGLT-20x20-B-KIT is electrical equipment and must not be disposed of with household waste. It must be taken to an appropriate collection point for waste electrical and electronic equipment or returned to the manufacturer. Batteries and rechargeable batteries must be removed and disposed of separately in accordance with the applicable regulations.