# Tailoring the V-Model for Optics: A Methodology for Optomechatronic Systems
## 3 Concretization of the V-Model for High Resolution Lighting Systems
#### 3.2.2 Steps for the Non-Sequential Detailed Design (NSC-Design)  
For the analysis of scattered and reflected light, as well as absorption losses in the optical system, a non-sequential detailed design is used, allowing conclusions about the optical efficiency of the system (cf. Section 3.2). Therefore, the simplified emission characteristics and area of the light source(s) of the sequential detailed design have to be replaced by a more realistic light source. * **Set up light source and NSC-Design:** The simplified emission characteristics and area of the light source of the sequential detailed design is replaced by a so-called ray file, from which the measured spatially resolved radiance of the light source from different angular positions is described [78]. Alternatively, a modeling of the light source with appropriate angular and spatial resolution of the luminous intensity can be carried out according to the data sheet. Subsequently, the number of rays required for tracing has to be determined, which should be high in terms of an accurate conclusion about the efficiency. Furthermore, the luminous flux of the source, as well as the emitted wavelength(s), have to be specified. For precise statements about the efficiency of the high-resolution lighting system, not only the light source but also the light modulator must be modeled as accurately as possible, and material, coating and scattering definitions must be assigned to the optical volume elements (lenses, prisms, etc.). * **Perform ray trace:** Taking into account the angular and spatially resolved luminous intensity of the light source, a defined number of rays are traced through the optical system. The single rays are affected by different optical effects like refraction, diffraction, (total) reflection, scattering, splitting or absorption or a combination of these effects, which depend on the assigned material, coating and scattering definitions as well as on the individual optical elements. * **Evaluate efficiency of the NSC-Design:** The evaluation of the efficiency of the non-sequential detailed design is carried out on the basis of the performed ray trace. In addition to determining the overall efficiency, it is also recommended to determine the efficiencies of the individual optical elements in order to be able to conduct targeted measures to increase efficiency during optimization loops. If the overall efficiency and/or the photometric requirements (e.g., lighting functions to be realized or photometric quantities) of the high-resolution lighting system are not met, it is advisable to return to the design step \"Functional surfaces, parameters and boundary conditions\". If no improvement is achieved despite running through this loop several times, a second loop must be used to return to the phase of preliminary design (cf. Figure 9). * **Identify stray light sources**: In order to identify unwanted scattered and reflected light, which may have negative effects on the optical properties of the non-sequential detailed design, a stray light analysis must be performed. Both optical and mechanical components that lead to an unwanted reduction in contrast and/or image quality are analyzed. An effective approach to identify stray light at surfaces of the optical and optomechanical design is to examine the optical system from the object and image sides. For this purpose, based on the previously performed ray trace, selected rays are analyzed with respect to their interaction with surfaces and subsequently measures for the reduction of stray light are implemented. According to [PERSON] [79], the application of anti-reflective coatings, the positioning of aperture stops at suitable points in the optical path or the constructive redesign of individual components are particularly effective measures for the reduction of stray light. The exchange of information between the optics and mechanics domain is therefore essential with regard to the respective domain-specific design (cf. Figure 8).