Essentials of Phosphor Technology (PH338)

SynopsisThe past few decades witnessed a rapid growth in the LED industry with an extensive proliferation of white LEDs components, LED backlights, lamps, luminaires and illumination systems in the industry. Along with this rapid growth many personnel find themselves getting involved in the development and manufacturing of phosphor-converted light sources, particularly phosphor-converted white LEDs or remote phosphor converted light sources. Phosphor technology as a course is rarely taught in depth or taught at all in the engineering courses and in the basic or applied sciences. As such there is a need to update the knowledge of such personnel in the area of phosphor technology.

It is essential that engineers and other personnel involved in R&D, product specifications of LED and the marketing of white LED illumination products have a firm grasp of the fundamentals of solid-state lighting technology, in particular the phosphor technology being the core of the technology that generates various color temperatures for back lighting and illumination purposes.

With this in mind, this course is designed to provide the participants with a broad understanding of the basic theory and practical aspects of phosphor technology and its related disciplines required to understand it.

Course Highlight
This course is developed to provide a better understanding in the field of phosphor technology, in particular in its application to LEDs and solid-state lighting. The areas covered include the physics of phosphor light conversion and emission color, phosphor materials, its properties and specifications, and its manufacturing. Discussions will be carried out related to the use of phosphor in LED light conversion, the deposition techniques on LEDs, and the encapsulation materials for phosphors. Also, potential issues like efficiency degradation and luminance saturation will be discussed.

This course is designed to provide a basic understanding of concepts and issues related to white LED phosphors, beginning with the basic physical concepts. An introduction is given of typical phosphors describing how the phosphor absorb blue light and re-emit the light in longer wavelengths. The factors determining the absorption and emission wavelengths are discussed. Next we look at the tuning of the emission and absorption wavelength based on energy levels of an activator ion in a crystal structure. A survey is carried out on the phenomena of thermal quenching of phosphors, efficiency degradation and luminance saturation under increased power input, and the possible reasons for it.

What You Will Learn

• Fundamental concepts of luminescence in solids
• Atomic structure and radiation
• Radiative and non-radiative decay processes
• Basic concepts of optical spectroscopy
• Excitation and the factors determining absorption and emission of wavelengths
• Energy level structure of lanthanides and transition metal ions
• Overview of phosphor materials and technologies for LED applications
• Phosphor manufacturing processes
• Interaction between phosphor and LED emissions
• Deposition techniques for white LEDs and other colors.
• Color temperature targeting and controls
• Color quality measurement of phosphor-based illumination sources
• Challenges for lighting phosphors

Who Should AttendThe primary target audience for this course is for people involved in R&D, manufacturing, test, product and application engineering, as well as quality and reliability engineering of white LEDs and related downstream illumination products. Application engineers and marketing personnel involved in white LED end products will find this introductory course informative and helpful, as it will help them to communicate clearly illumination data and specification to their customers, particularly white LED products.
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The target audience:

• Project Managers
• Program Managers
• Test Engineers
• Mechanical Engineers
• Quality and Reliability Engineers
• Failure Analysis Engineers
• Application Engineers
• Technical Marketing and Sales Engineers

PrerequisiteInterest in the science of phosphor technology as applied to LEDs and its end products. Technical background in electrical/electronic/mechanical engineering, material science, or physics degree would be desirable. A basic knowledge of optics, photometric quantities and color science is desirable but not essential.

Course MethodologyThis course is presented classroom style.

Course Duration2 days, 9am - 5pm

Course StructureIntroduction to Optical Quantities

• Nature of light
• Photometric quantities
• Colorimetric quantities

• Fundamental concepts of luminescence in solids
• Atomic structure and radiative emission
• Radiative and non-radiative decay processes
• Phosphorescence and fluorescence
• Introduction to spectroscopy and its use in phosphor measurements
• Absorption and emission of wavelengths in phosphors
• Relationship with energy level structure of transition metals

• Classification of phosphor materials
• Applications to LEDs
• Intellectual property landscape and issues
• Specifications for phosphors
• Manufacturing processes and quality control involved in producing phosphor
• Interaction between phosphor and LED emission
• Color temperature targeting and controls
• Measuring color quality of phosphor-converted LEDs
• Color temperature and Color Rendering Index
• ANSI C78.377 color specification for white LED products
• Phosphor and encapsulation materials
• Phosphor deposition techniques and process controls
• Challenges for lighting phosphors