Harold Hopkins (physicist) facts for kids
Quick facts for kids
Harold Hopkins
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| Born | 6 December 1918 Leicester, England, UK
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| Died | 22 October 1994 (aged 75) Reading, England, UK
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| Nationality | British |
| Known for | Zoom lens Fiberscopes Rod lens endoscopes for keyhole surgery Optics for laserdisc/CD Borescopes Wave Theory of Aberrations |
| Awards | SPIE Gold Medal (1982) Rumford Medal (1984) Lister Medal (1990) Fellow of the Royal Society |
| Scientific career | |
| Fields | Physics, Optics, Mathematics |
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| Notable students | Ashok Sisodia María Yzuel |
Harold Horace Hopkins (6 December 1918 – 22 October 1994) was a brilliant British physicist. He created a special way to understand how light behaves, called the Wave Theory of Aberrations. This theory helps computers design amazing lenses today.
Besides his theories, he invented many things we use every day. These include zoom lenses, special fiber-optic tools, and rod-lens endoscopes. These endoscopes made modern "keyhole surgery" possible. He won many top awards and was even nominated for a Nobel Prize twice. In 1984, when he received the Rumford Medal, it was for his "many contributions to the theory and design of optical instruments." This especially included new medical tools that greatly helped doctors with diagnosis and surgery.
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Harold Hopkins' Life Story
Harold Hopkins was born in 1918 in a poor part of Leicester, England. People quickly noticed how smart he was. Thanks to his talent and support from his family and teachers, he won one of only two scholarships in all of Leicestershire. This allowed him to attend The Gateway Grammar School. He was excellent in many subjects, including arts, English, and history. However, his headmaster saw his amazing gift for mathematics and guided him toward science.
He studied physics and math at University College, Leicester, graduating in 1939. He then started a PhD in nuclear physics. But World War II began, and his PhD was put on hold. He started working for Taylor, Taylor & Hobson, where he learned about designing optical tools.
During the war, he was briefly trained to blow up bridges! But soon, people realized his skills were better used elsewhere. He spent the rest of the war designing optical systems. At the same time, he worked on his PhD thesis, which he finished in 1945.
In 1947, he began a research job at Imperial College London, teaching about optics. For the next 20 years, he became one of the top experts in optics. Many smart PhD students from all over the world came to study with him. Many of them became important scientists themselves. He was known as an amazing teacher. Even when he moved to Reading University in 1967, many of his old students would travel to hear his lectures. He always believed that teaching was his most important job, even more than research. But he also felt that teaching and research helped each other. He said, "Only when you try to teach something do you discover whether you truly understand it."
He used a lot of math in his work. Developing mathematical ways to describe how optical systems work was central to his life's physics. This led to many famous inventions. He stayed at Reading as a Professor until he retired in 1984, even though he was offered many other top jobs. He felt that continuing his teaching and research was more important and personally rewarding. He was very proud to become an Honorary Fellow of all the medical Royal Colleges in Britain. He also received top awards from many leading science groups, including the Royal Society in 1973. In 1990, he won the Lister Medal for his work in surgical science. This award is usually given to doctors, so it was special for a physicist to receive it for his work on endoscopes. He also received the Frederic Ives Medal from the OSA in 1978.
Harold Hopkins also believed strongly in fairness and equal chances for everyone. Coming from a less wealthy background, he understood how important good education was for young people to succeed in society.
Amazing Inventions and Improvements
How Zoom Lenses Work
In the late 1940s, the BBC asked for a single camera lens that could zoom in and out. Before this, camera operators had to switch between different lenses. Hopkins then created the zoom lens we know today. Earlier zoom lenses existed, but they didn't give a clear image when zooming. Designing a zoom lens is much harder than a fixed lens.
Hopkins' zoom lens changed television images, especially for outdoor broadcasts. It opened the way for zooming to be used everywhere in videos today. What's even more amazing is that he designed it before computers were common. He did the complex calculations using large mechanical machines. While early zoom lenses weren't as perfect as fixed lenses, his work, combined with new glass types and computer design, made them much better.
Fiber Optics and Medical Tools
Understanding Fiber Optics
Ancient Romans knew that if you heated glass and pulled it into very thin fibers, light could travel through them. This happens because light bounces off the inside surfaces of the fiber. However, a single fiber can't carry a clear image because the light rays get mixed up. The light coming out is just an average of the light that went in.
Making Coherent Fiber Optics
Imagine a bundle of many tiny fibers. If the ends of these fibers are perfectly lined up at both sides, then an image focused on one end can be seen as a "pixelated" picture at the other end. In the 1930s, a German student named Heinrich Lamm made a simple bundle with about 400 fibers. But many fibers were out of place, and light leaked between them, making the image blurry. To get a useful image, a bundle needed tens of thousands of perfectly aligned fibers.
In the early 1950s, Hopkins found a way to do this. He figured out how to wind a single, long fiber in a figure-of-eight shape around two drums. Once enough turns were made, he could seal a section in resin, cut it, and straighten it out. This created a "coherent bundle" where all the fibers were correctly aligned. After polishing the ends, he added lenses he designed for viewing. When this was put into a flexible tube, the "fibroscope" (now called a fiberscope) was born! He published his ideas in 1954 and 1955.
At the same time, a Dutch scientist, Abraham van Heel, was also working on fiber bundles. He found a way to cover each fiber with another layer of glass. This "cladding" stopped light from leaking between fibers. Later, Larry Curtis and others developed a better cladding system. This made fiberscopes work to their full potential.
Fiberscopes and Borescopes in Use
Fiberscopes became very useful in medicine and industry. In industry, they are often called borescopes. Another big improvement was adding more fibers to carry light from a powerful outside source to the end of the scope. This gave bright, full-color light for clear viewing and good photos. It also kept the scope cool, which was very important for medical uses. Before this, tiny lamps at the end of the scope could burn the patient if they were too bright.
For medical uses, fiberscopes also got controls to steer the tip. Doctors could also use small surgical tools through the scope. This was the start of modern keyhole surgery. These advances were also helpful in industry.
Rod-Lens Endoscopes: A Clearer View
Fiberscopes have limits to how clear their images can be. A bundle of 50,000 fibers gives an image with only 50,000 "pixels." Also, bending the scope over time breaks fibers, making the image worse. Hopkins realized that to get even better images, a different approach was needed.
Older rigid endoscopes had very dim and blurry images. To fit surgical tools and lights inside the narrow tube (which had to fit inside the human body), there was little space left for the imaging lenses. The tiny lenses in old systems needed thick support rings that blocked most of the light. They were also very hard to make.
In the 1960s, Hopkins came up with a brilliant solution: use glass rods instead of tiny lenses. These rods filled the air spaces inside the endoscope tube. They fit perfectly, so they didn't need support rings. They were also much easier to make and used the largest possible diameter for light. Like with fiberscopes, a bundle of glass fibers brought light from an outside source. Hopkins carefully calculated the curves and coatings for the rod ends and chose the best types of glass. This completely changed image quality. Light levels became 80 times brighter with no heat. Fine details could finally be seen clearly, colors were true, and scopes could be as small as a few millimeters. With such a high-quality "telescope" inside, surgical tools and lights could easily fit in the outer tube.
Hopkins patented his rod-lens system in 1959. A company called Karl Storz GmbH saw how promising it was and bought the patent. In 1967, they started making endoscopes with incredibly bright and clear images. This began a long and successful partnership between Hopkins and Storz. While flexible endoscopes are still needed for some body parts (like the digestive system), the rigid rod-lens endoscopes are so good that they are still the top choice for many procedures. They truly made modern keyhole surgery possible.
Measuring Image Quality: MTF
Before Hopkins' work, people mainly checked how clear an optical system was by looking at special charts. But Harold studied with Pierre-Michel Duffieux, who was starting to explore a new way to understand optics using math.
In 1962, Hopkins gave an important speech where he introduced the "modulation transfer function" (MTF). This is a way to measure how well an optical system forms an image. Simply put, it measures how well a lens can show the contrast (difference between light and dark) of very fine patterns. MTF is still used by lens designers today as the main way to judge image quality. Computer programs like OSLO, Zemax, and Code V calculate MTF from lens design data.
Optics for Laserdiscs and CDs
The Philips laserdisc was an early system for playing video. In the late 1970s, it was updated to use digital information and became the basis for CDs and DVDs. Digital data is stored as tiny bumps and pits on a shiny disc. A laser reads these along a spiral path, much like a needle on a record. The laser must focus on this path, and the reflected light needs to be collected and measured.
The first systems used expensive glass lenses. But Hopkins, using his detailed mathematical analysis, showed that a single piece of clear molded plastic could do the job if designed carefully. This discovery is a major reason why laser disc players (like CD players) are so affordable today.
The Hopkins Building at Reading University
On June 12, 2009, the Hopkins Building at the University of Reading was officially opened. His son, Kelvin Hopkins, a Member of Parliament, attended the ceremony. This building brings together the university's research in biomedical and pharmaceutical fields. While not directly about optics, this new facility honors Harold Hopkins as one of the university's most famous academics. It continues his belief in high standards for teaching and research.
