Introduction

“Oh yes, I have LEDs in my house!” This speaker probably means to say LED light bulbs or LED flashlights, not bare LED chips. This brief chapter will illustrate how LEDs are widespread today in our lives, where the term “LED” can mean various stages of LED products, from millimeter-sized bare chips to gorgeous building lighting luminaires. Based on this understanding, the following discussion positions this book in the LED world and the scope of this book is made clear. This chapter will also discuss the LED and SSL briefly in a context of lighting history. Finally it closes with a discussion on a very important issue, the safety around LEDs.