Detecting Small Lens Defects: The Power of Basson 5x Telecentric Lens

Even the cleanest glass lenses can present a problem when installed in a lens system–the appearance of black spots in the image. The presence of these black spots is not always due to visible dirt. More often than not, they can be attributed to minuscule flaws on the lens itself that are extremely difficult to detect with the naked eye. These imperfections include bubbles, scratches, and other irregularities that can occur during the manufacturing process of the lens. Detecting these almost invisible defects is a challenge, but one that has been effectively addressed with the development of advanced optical technologies, particularly the Basson 5x telecentric lens.

Lens defects, no matter how small, can have a profound impact on the quality of the images captured. A simple black spot in the image can distort the visual information, making it less reliable for various applications. In fields such as medical imaging, where accurate visualization of internal structures is crucial for diagnosis, even the tiniest flaw in the lens can lead to misinterpretation of the images. In the semiconductor industry, where lenses are used for inspection, these defects can cause errors in the manufacturing process, resulting in costly production delays and defective products. In photography, whether it’s for commercial or artistic purposes, lens defects can ruin an otherwise perfect shot. The presence of black spots can draw the viewer’s attention away from the subject, detracting from the overall aesthetic appeal of the image. In surveillance systems, clear and accurate images are essential for security purposes. Small lens defects can make it difficult to identify individuals or detect suspicious activities, undermining the effectiveness of the surveillance system.

Bubbles are one of the common invisible defects found in glass lenses. These bubbles are formed during the melting and shaping process of the glass. When the glass is in a molten state, gas can get trapped inside, creating bubbles. These bubbles can vary in size, from tiny microscopic ones to slightly larger ones that are still difficult to see without the aid of specialized equipment. Bubbles can scatter light as it passes through the lens, causing optical aberrations and reducing the clarity and sharpness of the image. Scratches are another type of defect that can occur on the surface of the lens. Even the slightest scratch can disrupt the smooth flow of light through the lens, leading to glare or black spots in the image. Scratches can also affect the lens’s ability to focus light accurately, resulting in blurry images.

Visual inspection is one of the most basic methods of detecting lens defects. However, this method is highly subjective and dependent on the individual’s eyesight and experience. Small defects, especially those that are less than a few microns in size, are easily overlooked. Even with the use of magnifying glasses, it can be challenging to detect some of the more subtle defects, such as tiny bubbles or scratches that are not in the direct line of sight. Optical microscopy is a more advanced method of defect detection. It uses a combination of lenses and light sources to magnify the image of the lens, allowing for a closer examination of its surface. However, traditional optical microscopes have limitations. The depth of field is often limited, meaning that it can be difficult to focus on all parts of the lens simultaneously. This can result in some defects being missed if they are not in the plane of focus. Additionally, the magnification capabilities of optical microscopes are also limited, and they may not be able to resolve some of the smallest defects, especially those in the sub-micron range.

In the optical industry, the Basson 5x telecentric lens is widely used for the inspection of glass lenses during the manufacturing process. It can be used at various stages, from the initial raw material inspection to the final quality control check. By detecting defects early in the production process, manufacturers can take corrective measures to improve the quality of the lenses, reducing the number of defective products and saving costs associated with rework or scrap.

In a telecentric lens, the chief ray is parallel to the optical axis both in the object and image spaces. This means that the magnification of the lens is independent of the object’s distance from the lens within a certain range. The Basson 5x telecentric lens is designed based on this principle. It has a carefully engineered optical system that ensures the light rays enter and exit the lens in a parallel manner, minimizing distortion and providing a clear and accurate view of the object being inspected. This is particularly important when detecting small defects, as any distortion can make it difficult to accurately identify and measure the defects.

The Basson 5x telecentric lens offers a magnification of 5x, which is sufficient to bring out even the tiniest details of the lens. This high magnification, combined with its excellent resolution capabilities, allows for the detection of defects in the micron and even sub-micron range. The lens is able to resolve features as small as a few micrometers, making it possible to clearly identify and analyze defects such as bubbles, scratches, and inclusions that were previously undetectable. One of the significant advantages of the Basson 5x telecentric lens is its wide depth of field. Unlike traditional optical microscopes, which have a limited depth of field, the Basson lens can focus on multiple planes within the lens simultaneously. This means that it can capture clear images of defects that are located at different depths within the lens, whether they are on the surface or deep inside the glass structure. This feature is crucial for detecting a wide range of defects and ensuring that no potential flaws are overlooked.

The Basson 5x telecentric lens is designed to provide uniform illumination across the field of view. This is essential for accurate defect detection, as uneven illumination can create shadows and glare, making it difficult to identify defects. This uniform illumination also helps in obtaining accurate measurements of the defects, as the contrast between the defect and the surrounding area is optimized. As mentioned earlier, telecentric lenses are known for their low distortion characteristics. The Basson 5x telecentric lens is no exception. It minimizes geometric distortion, ensuring that the shape and size of the defects are accurately represented in the image. In the optical industry, the Basson 5x telecentric lens is widely used for the inspection of glass lenses during the manufacturing process. It can be used at various stages, from the initial raw material inspection to the final quality control check. By detecting defects early in the production process, manufacturers can take corrective measures to improve the quality of the lenses, reducing the number of defective products and saving costs associated with rework or scrap.

The Basson 5x telecentric lens is designed to be easily integrated with existing inspection systems. It can be mounted on a variety of optical microscopes, imaging systems, and automated inspection equipment. The lens is compatible with different types of light sources and cameras, making it a versatile solution for defect detection. Regular maintenance and calibration are important to ensure the long-term performance of the Basson 5x telecentric lens. Special cleaning solutions and tools are recommended to avoid scratching the lens. Calibration of the lens is also necessary to ensure accurate measurement and defect detection. The calibration process involves adjusting the focus, magnification, and other parameters to ensure that it is operating within the specified tolerance.

Basson 5x telecentric lens has emerged as a powerful solution. With its high magnification, wide depth of field, uniform illumination, and low distortion, it is able to detect even the most invisible defects in glass lenses and other optical components.

Basson focuses on machine vision products used for precision measurement and defect detection.

Basson not only provides high-precision bi-telecentric lens systems, telecentric lens systems, telecentric light sources, coaxial illuminations and optical lenses, but also offers customized services.

With products designed in Germany, business planned in the UK and products made in China, Basson is able to provide superior products to customers through its global team. Currently, Basson is in preparation of production and assembly of products in Japan.

Dr. Liu Lu, acting as CTO of Basson, is a PhD degree holder of Oxford University.

Production and testing instruments include optical vacuum coating machines manufactured by Satis in Switzerland and Leybold in Germany, a laser interferometer from Zygo in the US, a spectrophotometer from PerkinElmer in the US, a spherometer from Hofbauer Optik in Germany, a centering instrument from Kyoritsu Electric in Japan, a NC grinding device made by Kojima Engineering in Japan and an automatic centering machine made by Shonan in Japan.