The DMD inside

By opening the PK101, the Nikkei Electronics Teardown Squad has revealed the optical module containing the display elements such as DMD and LED light source as well as optical parts. The main substrate has a DMD driver LSI and a few other electronic parts. Two large LSIs stood out from the other parts on the substrate. One is an image processing LSI manufactured by Weltrend Semiconductor Inc of Taiwan, which is sealed by a 14 x 14mm package. The other is a DMD driver LSI manufactured by Texas Instruments Inc (TI) of the US.

TI markets the driver LSI with a DMD as "DLP Pico chipset," targeting ultra-small projectors. The 0.17-inch DMD, which was downsized by reducing the number of pixels, features 480 x 320 pixels.

Meanwhile, the driver LSI, which is 14 x 14mm, looks too big to be used in an ultra-small projector.

The DMD is mounted on a small substrate, which is sterically connected with the main substrate by a connector. Projectors that use the DMD as a display element usually employ a flexible substrate to connect the main substrate with the DMD. It seems that priority was placed on ease of assembly in respect to this model.

The optical module

The Nikkei Electronics Teardown Squad opened the chassis of the PK101 and took out the optical module. The red, green and blue (RGB) LED light sources bonded to the copper sheet came off together with the sheet. The flexible substrate on which the light sources were mounted was printed with the logo of Young Optics Inc of Taiwan.

The team could not identify the manufacturer of the LEDs, but they were assumed to have been "made by a Taiwanese manufacturer," according to a marketer of an LED manufacturer.

Fly-eye lens like

The Nikkei team finally opened the optical module. The module "sticks to the basics" of optical design, said an engineer who is familiar with projectors. But its optical parts were quite distinctive. The engineer focused on the fly-eye lens, which has an array of small lenses on the surface.

It seemed that the lens was employed as an "integrator" to reduce variations in the brightness of images by equalizing the luminance of light incident to DMD display device. Projectors with DMD generally use a rod lens as an integrator, the engineers said.

Each lens in the fly-eye lens is shaped like a parallelogram. It was "designed probably to efficiently introduce light into each of the micron-order mirrors in the DMD," the engineer said. In addition to this lens, the mirror located near DMD was tilted in horizontal and vertical directions so that light effectively enters the DMD micromirrors.

The MPro110

Following the "PK101," which uses DMD (digital micromirror device) as a display element, the Nikkei team started breaking down the "MPro110" equipped with an LCOS (liquid crystal on silicon) display. As in the case of the PK101, the team removed the Li-ion secondary battery from the chassis and unscrewed the screws to open the chassis. Neither the name nor the logo of a manufacturer was printed on the battery. An engineer from a component manufacturer who is well-versed in secondary batteries guessed the manufacturer from the battery's shape and capacity and said, "This is probably a product of a Japanese manufacturer, I guess."

The inside of the chassis, which consists of an optical module and the main board, looked almost the same as the PK101's inside. The optical module includes an LCOS display, an LED light source and optical components. The main board is mounted with an LCOS driver LSI and various electronic components. Among the components located inside the chassis, the radiation fin stood out the most because it is rather big for the chassis, which is as small as a portable music player.