[Kinect Teardown (6)] Elaborately Controlled Laser Temperature
Continued from [Kinect Teardown (5)] 3 Circuit Boards Examined
The teardown of the Kinect entered its final phase. We removed circuit boards from the middle and third layers of the three-layer structure. The rest was the first layer equipped with an infrared laser, a camera for infrared light and a camera capable of detecting visible light. The laser and cameras were mounted on a large metal part.
We detached the laser and cameras from the metal part. Engineers who participated in the teardown were interested in how the laser was cooled. They assumed that Microsoft Corp focused on cooling the laser because it was mounted on the large metal part, which has a high thermal conductivity, and a radiation fin was found near the laser.
In the first place, lasers are optical components that are sensitive to temperature changes. For example, the oscillation wavelength of a laser changes depending on temperature.
For devices equipped with lasers, their optical designs are made in accordance with the properties of the lasers such as oscillation wavelength. Therefore, it is necessary to reduce temperature changes to prevent the properties from changing.
When we further torn down the area around the laser, we found that the temperature of the laser was more carefully adjusted compared with the temperatures of other electronic components of the Kinect. On the back of the laser, there was a component that seemed to be a peltier device for cooling.
The radiating part of the laser was glowing in iridescent color, reflecting room light. Also, the light receiving part of the camera used to detect infrared light was reflecting room light. Both of them were reflecting room light probably because they had a filter function that transmits infrared light.