The optical design of camera modules is a complex and intricate process that involves multiple key elements and technical indicators. Here are some basic principles of the optical design of camera modules:
Optical Path Design
The light signal transmission path of the camera module should be as short as possible to reduce signal loss and distortion. The light signal enters through the lens, passes through the filter, and finally reaches the photosensitive element.
Complementary Metal-Oxide-Semiconductor (CMOS) image sensor). -> Period.
The lens design should ensure that the light signal can be efficiently and accurately focused on the photosensitive element. The lens is usually composed of multiple optical elements, each with a specific function, such as correcting aberrations and improving transmittance.
Aberration Correction
Spherical aberration: 通过合理设计透镜的曲率和厚度,减小球面像差,使图像更清晰。
Chromatic aberration: multi-layer coatings or special materials for optical elements, the dispersion of different wavelength lights is reduced, improving image quality.
By optimizing the lens structure, the reduction of image distortion is particularly noticeable in the edge areas.
Field curvature: Adjusting the lens design keeps the entire image plane on a flat surface, reducing the caused by field curvature.
By designing a reasonable lens structure, barrel distortion and pincushion distortion are reduced, making the image more realistic.
Aperture Design
Aperture size: The size of the aperture directly affects the amount of light and depth of field. A larger aperture increases the light but the depth of field; a smaller aperture increases the depth of field but reduces the light. The design needs to be balanced according to the application scenario.
Aperture mechanism: Modern camera modules are usually equipped with adjustable apertures to adapt to different lighting conditions.
Infrared filter: The filter is to filter out infrared light to prevent it from affecting image quality.
A UV filter can reduce the interference of ultraviolet light on the image.
A polarizing filter can reduce the interference of reflected light, improving the contrast of the image.
Photosensitive Element Design
Photosensitive element: Common photosensitive elements are CMOS and CCD. CMOS is widely used due to its low power consumption and low cost, while CCD is more common in-end applications.
Pixel size: The size of the pixel directly affects the resolution and sensitivity of the image. Larger pixels increase sensitivity but decrease resolution; smaller pixels increase but decrease sensitivity.
Dynamic range: The dynamic range of the photosensitive element determines its performance in high dynamic scenes. A high dynamic range element can achieve better results environments with strong light and dark contrasts.
Encapsulation Technology
MOB Technology: MOB (Molding on Board) technology encapsulates electronic components within a mold, an integrated structure. This enhances the stability and reliability of the module.
MOC Technology: MOC (Molding on Chip) technology further advances MOB by encaps the gold wires within the mold, connecting them directly to the chip. This further enhances the reliability and performance of the encapsulation.
Environmental Adaptability
Temperature Adaptability: Camera modules need to maintain stable performance in different temperature environments. Design considerations should include the thermal expansion coefficient and thermal stability of materials.
Dust Water Resistance: 用于户外应用的摄像头模块,需要具备防尘和防水设计,以确保在恶劣条件下正常运行。
Cost Control
Choosing materials wisely can balance performance and cost.
Optimizing the production process can enhance production efficiency and reduce costs.
By following these principles, high-performance, high-reliability camera modules can be designed to meet the demands of various application scenarios.