An exemplary method and apparatus are provided for data transmission in an optical transport network that includes receiving client data from a client, mapping the client data into a frame structure, mapping the frame structure into tributary slots of a data transport structure, and transmitting the data transport structure. The first flow channel includes a first end connected to the load port and a second end that opens into a first reservoir of the sample holder. The system can be quickly or automatically adjusted for building walls with various sized studs, stud spacing, and for building walls of varying height. In some embodiments the partially reflective mirror comprises a metal layer that has a plurality of openings. Consequently, the methods provide a means to perform validation on an integrated level whereby the quality control unit can ensure data and product integrity and minimize cost. As an illuminating optical system is provided rotatably around an optical axis of a projecting optical system, the position of the illuminating optical system can be varied depending on whether the projector device is used or not used, and the overall thickness of the projector device can be thereby reduced.