In November 2024, Samsung Electronics won a total of 29 'CES Innovation Awards® 2025' ahead of the world's largest and most influential technology event, 'CES 2025'. One Samsung technology honored with a CES 2025 Innovation Award is All Lenses on Prism (ALoP). This revolutionary approach to lens and sensor placement uses a folded zoom structure to place camera lenses directly on the camera prism, reducing camera module size and improving brightness. In this third installment of our CES Innovation Awards interview series, we sat down with Younggyu Jeong (Task Leader) and Minook Kim (Staff Engineer) from the Sensor Solutions Team to learn more about ALoP.
Q. For those unfamiliar with the product, what is ALoP?
Younggyu Jeong: ALoP, or All Lenses on Prism, is a new folded zoom structure for smartphone telephoto cameras. By placing the lenses on top of the prism, it reduces size of module while enabling brighter image capture. Telephoto cameras with high zoom ratio require long focal lengths. This is why large cameras like DSLRs have long lens barrels. However, smartphone cameras cannot endlessly increase the camera height due to limitations on space, so they primarily use folded zoom structures where prisms bend the path of light 90 degrees. While conventional folded zoom structures place the lenses between the prism and the sensor, ALoP places the lenses right on top of the prism, reducing the overall module length.
Q. ALoP is a solution for telephoto cameras. Why is the need for better telephoto cameras for smartphones becoming so important?
Minook Kim: Mobile cameras have been consistently evolving to achieve better image quality by incorporating larger image sensors. The main camera sensors used in smartphones, wide-angle cameras, are already reaching a size ranging from 1” to 1/1.3”, which is considered the upper limit for implementation in modern smartphones.
This is why telephoto cameras are becoming a new point of differentiation for smartphone manufacturers. Telephoto cameras offer high-magnification zoom capabilities and can also be highly effective for taking portraits. Telephoto cameras can compress the background and reduce subject distortion due to the narrow field of view, and even create a suitable background blur effect.
Q. What direction is the industry taking in telephoto camera development?
Younggyu Jeong: When telephoto cameras were first introduced to smartphones, they were released with low zoom ratio such as 2x (50mm). As smartphone cameras evolve with larger sensors and higher zoom ratio, folded zoom technology emerged, bending the path of light by 90 degrees like a periscope to allow for longer focal lengths horizontally without extending the thickness of smartphone vertically. This made higher magnification telephoto cameras in smartphones possible.
But previous folded zoom structures have had limitations in achieving bright cameras with a low F/#. Often written like F/2.6, a camera’s F/# is the ratio of the lens’ diameter compared to its focal length—the lower the number, the brighter the photos you get under identical lighting conditions. In cameras designed for specific focal lengths, the lens diameter needs to be increased in order to decrease the F/#. However, since the lens is mounted vertically on the smartphone, using a larger lens for brighter results would make the smartphone itself thicker, so another solution needs to be found.
In addition, most modern smartphones have multiple cameras, so if there is a big brightness difference between the wide-angle camera and the telephoto camera, the transition between cameras when changing zoom magnification may not be seamless.
To address these issues, the industry has been looking for a solution that can achieve a better F/# than traditional folded zoom structures. That is why we developed ALoP.
Minook Kim: We also need to talk about the camera bump. Telephoto cameras with high magnification inherently require a longer distance from the lens to the sensor, resulting in a taller camera module. While the emergence of folded zoom technology has allowed higher magnification telephoto cameras to be implemented within the limited space of a smartphone, many consumers still experience inconvenience due to the large and thick camera bump. That’s why the industry is looking for smaller and thinner telephoto camera solutions like ALoP.
Q. What are the differences between conventional folded zoom and ALoP?
Minook Kim: In a conventional folded zoom structure, light entering the camera is refracted 90 degrees by the prism, then passes through the lenses and enters the sensor. In contrast, ALoP positions the lenses horizontally on top of the prism, allowing light to pass through the lenses first, then refract through the prism before reaching the sensor. By placing the lenses in the previously empty space, it improves design efficiency and shortens the module length. It also offers the advantage of capturing subjects brightly and clearly even in dark environments.
Q. How does ALoP capture subjects brightly and clearly in low-light environments?
Minook Kim: As we mentioned earlier, to capture bright images with a lower F/#, a larger lens diameter is beneficial. In conventional folded zoom, the lenses are mounted vertically on the module, so using larger lenses would increase the module height, leading to an increase in the overall thickness of the smartphone. In contrast, ALoP positions the lenses horizontally on the module, enabling the use of larger lenses. This allows more light to be captured, thereby increasing the camera’s signal-to-noise ratio (SNR) without affecting the smartphone's thickness. The result is clearer, brighter images even in dark environments.
Q. You previously explained that ALoP is an effective way to reduce module size. What are the benefits of a smaller module from a smartphone device perspective?
Younggyu Jeong: A smaller camera module reduces the area and height of the camera bump, providing a more aesthetically pleasing smartphone design. From a manufacturer's perspective, a smaller camera module also allows for more efficient component placement and space utilization within the device, contributing to improvements in other smartphone performance aspects like battery life.
Q. Are there any other advantages or features of ALoP?
Younggyu Jeong: In conventional folded zoom structures, the rectangular prism is exposed when viewing the telephoto camera from the outside of the smartphone, creating a sense of incongruity with other cameras that have circular lenses. ALoP, on the other hand, allows light to enter through a circular lens like other cameras, enabling a consistent design across all cameras.
Minook Kim: While conventional folded zoom prisms use a 45-degree reflecting surface, ALoP utilizes a 40-degree inclined reflecting surface. The sensor is also tilted by 10 degrees, resulting in a smaller module lens part height and sensor part height.
ALoP also employs a different autofocus mechanism compared to conventional folded zoom structures. Conventional folded zoom achieves autofocus by moving the vertically positioned lens horizontally. In contrast, ALoP implements autofocus through a unique method where the lens moves horizontally along with the prism. Since there is no lens movement in a vertical direction, it further reduces the module height. In this case, the tilted sensor angle causes a slight shift in the image center during AF, which is corrected by adjusting the lens position to align the image center.
Q. What unique challenges did you face during ALoP’s development?
Younggyu Jeong: When we first started developing ALoP, we collaborated closely with Corephotonics, an Israeli research institute, and went through many ups and downs with several strategic partners to implement the newly introduced concept for the telephoto camera. Through numerous deliberations, we enhanced the design completeness by continuously meeting with key component partners for several months. These deliberations included determining whether to use mirrors or prisms for the reflective optical system, how to design actuators for the new autofocus method, and how to optimize component shapes to minimize ghost and flare. We then spent four months developing a sample and proceeded with promotions based on them, which have been successful in attracting interest from numerous customers. We can’t wait to see the first smartphones equipped with ALoP hit the market.
Q. What do you think the future holds for the smartphone camera industry?
Younggyu Jeong: Smartphone cameras are rapidly evolving, but they haven't yet surpassed DSLR capabilities due to size constraints. I believe new technologies will continue to emerge to close that gap, with technologies aimed at improving the image quality of telephoto cameras, which are disadvantaged in terms of form factor, at the forefront.
As a business, we anticipate the commercialization of various technologies to reduce F/#, increase zoom magnification, and reduce module size. We will continue to combine the differentiated hardware solutions of ISOCELL with AI-based software solutions to expand users' mobile camera experiences.
ALoP, a revolutionary structure that enables smaller telephoto camera modules while capturing bright and clear photos, will be showcased at the Las Vegas Convention Center from January 7-10, 2025.
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