# Tailoring the V-Model for Optics: A Methodology for Optomechatronic Systems
## 3 Concretization of the V-Model for High Resolution Lighting Systems
#### 3.2.1 Design Steps for the Sequential Detailed Design (SC-Design)  
Based on the beam model, which was created using the method for the preliminary design of high-resolution lighting systems in the framework of the system design for optomechatronic systems, the sequential detailed design of the high-resolution lighting system is carried out first. In the first step, the emission characteristics and area of the light source are defined. * **Define emission characteristics and area:** Reduced to individual emission points--so-called fields, from which the spatial propagation of the rays emitted by the light source occurs--the size of the emission area is defined. For the description of the emission area, the arrangement of several fields is beneficial in order to achieve a high accuracy in ray shaping of the subsequent functional surfaces. Rays, which shall be considered by the following functional surface (e.g., mirror or surface of a lens) for shaping or deflection, can be defined by the emission angle of the fields as well as by the entrance pupil or numerical aperture of the functional surface. In addition, for both monochromatic and polychromatic light sources, the wavelength(s) must be specified. * **Set functional surfaces and parameters:** Based on the parameters obtained from the beam model, such as the type and number of optical elements for beam shaping and deflection, as well as the focal length and the image scale, the functional surfaces, parameters and boundary conditions of the optical system can be defined. Refractive optical elements such as lenses or prisms are defined by the combination of two respectively three functional surfaces in Zemax OpticStudio(r). The thickness of the optical element and the material are determined by the first functional surface. Reflective optical elements such as reflectors or plane mirrors are defined by a single functional surface, specifying reflective material properties. Once all functional surfaces for the sequential detailed design have been defined, functional surface parameters such as radii, materials or distances, which may or may not be changed during the optimization of the detailed design, are defined. To obtain a first approximation, it is advantageous to limit the number of variable parameters in the early phase of the detailed design. With increasing maturity of the sequential detailed design, the number of variable parameters of the functional surfaces can be increased in context of optimization loops. The parameter values should be limited in consideration of manufacturability and mountability of the optical elements. Finally, boundary conditions are defined, which arise in particular from the requirements initially elicited. * **Create Merit Function:** As an expression of design objectives to be met and achieved, a so-called merit function must first be defined for the optimization of the sequential detailed design. By restricting variable parameters due to minimum and/or maximum values, design goals to be met are defined. This may lead to several valid design solutions during optimization. An example is the length of the optical system, which should not exceed a certain maximum value due to requirements. Thus, with respect to the maximum length of the optical system, several designs can be developed to meet this requirement. If the variable parameters are defined by a single value, these are design goals to be achieved, with only one valid design solution. As an example of design objectives to be achieved, a defined field of view, which has to be illuminated according to the requirements, can be mentioned at this point. Design objectives to be met and achieved, which are derived from the requirements for the sequential detailed design, are thus coupled to the freedoms in the merit function, which in turn correlate with the number of variable parameters. * **Optimize SC-Design:** Within the optimization step, the optimization type, the optimization algorithm and the number of optimization cycles have to be defined.