The paper tells the reader explanation such as measurements, and angular response. Inside this paper the reader can read explanation about application, and sensor.
Lots of explanation related to light, and the photopic response are presented inside the paper. These are taken from this paper:
NUMBER 26 INTELLIGENT OPTO SENSOR DESIGNER’S NOTEBOOK Ambient Light Sensing (ALS) contributed by Joe Smith March 31, 2009 ABSTRACT The ability for a display to sense ambient light could be a powerful tool that can lead to increased power efficiency and customer satisfaction. WWW.TAOSINC.COM 4 OF 9 Ambient Light Sensing The true test of an ambient light sensor is how well it performs when compared to a calibrated light sensor under different lighting conditions.
Furthermore, the paper presents information things like photometric measurements, and ambient light sensing.