Introduction to Integral Sphere: From Principle to Application
Integral sphere is a hollow sphere, also known as a photometric sphere, a luminous sphere, etc. Usually, one or several windows are opened on the outer wall of the integrating sphere to serve as the light inlet, sample outlet, and light output outlet. Some integrating spheres are also equipped with standard whiteboards, optical traps, sample holders, hole plugs and other integrating sphere accessories to assist with various optical measurement requirements, etc. The inner wall is coated with an ideal white high diffuse reflection material, and the light entering the integrating sphere is reflected multiple times by the diffuse reflection layer on the inner wall, resulting in a uniform illumination that can eliminate the influence of uneven light beams. To achieve high measurement accuracy, the aperture ratio of the integrating sphere should be as small as possible. The aperture ratio is defined as the ratio of the area of the sphere at the opening of the integrating sphere to the area of the entire inner wall of the sphere. Each integrating sphere has a wide range of applicability and can be combined with spectrometers, optical fibers, light sources, and various optical measurement devices to form a system for various sample measurements, such as sample surface reflectivity, sample transmittance, light source radiation, and so on. The material of the diffuse reflection surface on the inner wall of the integrating sphere: The material of the diffuse reflection surface on the inner wall of the integrating sphere determines the service life, accuracy, stability, and so on of the integrating sphere. Usually, the materials of the diffuse reflection surface on the inner wall of the integrating sphere include PTFE, Baso4, and MGO2. The reflectivity curves of these three materials are shown in Figure (1): From Figure (1), it can be seen that in the spectral band of 200-2500nm, PTFE has a higher reflectivity than Baso4 and MGO2, and has excellent Lambert properties and a flat spectrum.
The parameters of different diffuse reflective coating materials are shown in Figure (2)
Introduction to Integral Sphere Light Source: Based on high-precision fine calibration and spectral matching technology, this uniform light source product can achieve free matching and control of color temperature, illumination (brightness), and spectrum. The adjustable extended light source is equipped with a spectral measurement system and an absolute radiance self calibration device, making the radiometric calibration light source a standard integral sphere light source with real-time calibration ability for output spectral radiance. It can simulate different scenarios as needed, serve fields such as healthcare and lighting, and also meet the needs of precise calibration of radiation values in scientific research, higher education institutions, and other fields.
Product Introduction: The spherical uniform light source benefits from its spherical structure and high reflectivity diffuse coating inside. The emitted light source has a surface uniformity and angle uniformity of over 99%, which can meet the high-end professional level uniform light source requirements. If you require uniformity of over 96%, you can also choose a small-sized, lightweight, and flexible surface light source that meets your needs for a large effective light output aperture.
Product features: The uniform light source series of this product has superior performance and flexible design. The outgoing light source has advantages such as high uniformity, wide dynamic range, and ultra-high brightness. It can achieve independent/coordinated control of emission parameters such as contrast, color temperature, and spectrum. In addition to conventional systems such as real-time monitoring of spectral radiance, it also has one click operation functions such as absolute spectral radiance self calibration and intelligent input automatic control of radiance.
Application areas: Optoelectronic imaging systems, optoelectronic testing systems, CCD/CMOS cameras, CCD/CMOS imaging devices, relative/absolute radiation calibration and testing, mobile phone cameras
The product has a wide spectral range and covers the entire spectrum from UV visible to near-infrared (200nm~2500nm). The integrated radiance can reach 120w/(m2sr) @ (400nm~900nm). The output spectral distribution can be tuned and the color can be adjusted to achieve spectral radiance output close to real scenery. Based on monochromatic LED with the same color and spectrum and wide color gamut simulation, it can be used for color calibration of optical remote sensors with a high stability radiance output of 0.5%/2h, meeting the requirements of long-term high stability calibration process. 99% of the radiance uniformity and 99% of the angle (Lambertian) uniformity provide high-quality Lambertian surface light source calibration that can be traced back to the National Institute of Metrology (NIM) of China and provide metrological calibration report software for monitoring and implementation. Output spectral radiance and chromaticity information
Technical Parameters
