This paper describes the development process of ambient light of the GV70 door trim garnish. For the first time in our company, we devised a specific lighting design to apply hidden pattern film mood lamp. Unforeseen problems difficult to respond via existent design process occurred during this process. In this article we articulate the development of ambient light by controlling new optical design factors by introducing novel material specs. Our study aims to share design standards and internalize lighting design capabilities. We identified the design factors of the mood lamp assembly consisting of light guide, diffuser, LED PCB and controller. Of the identified factors we selected those that affect target metrics, and performed evaluation test in various settings. According to the result of the test, we were able to comprehensively derive an optimal metrics for each factors with good cost and marketability. Target metrics was evaluated by assessing lighting area, maximum luminance, luminance uniformity and color uniformity. In the absence of objective parameters, scores were measured by subjective evaluation. Through this development activity, we developed our first hidden pattern film mood lamp and succeeded in mass-producing unique products that can appeal to consumers. The percentage of consumer choice for these lighting options was about 32%, which is significantly above the existing target. It has successfully achieved its target metrics despite reducing costs by minimizing module specs in LEDs, PCB, controllers and applying relatively inexpensive mold. From the perspective of systemic designing, we introduced new design factors that is open for further research. We also improved design capabilities by expanding design areas such as PC’s transmittance, diffuser’s MI, air gap and shadow zone standard, etc. However, there are also shortcomings in our development process. Frist of all, there was a lack of fundamental principle research, and the process of deriving quantitative design criteria was unclear. Developing design capabilities through additional research on each factor remains a future task. The fact that the hidden pattern’s marketability has not been maximized must also be noted. Initial goal of our task was to offer a completely new sense of impression as the light turns on. However, as the images observed by consumers before and after lighting turned out relatively similar, it fell short from our prior expectations. Existing mood lamp designs are often limited to optical pattern designs of light guide panels. On the other hands, our paper presents a method of designing a mood lamp by controlling various parameters outside of optical pattern such as material and layout. The methods proposed here will be of value when optic pattern design alone will prove difficult to achieve target goal, and when applied to the development of various types of ambient light with high completeness and individuality in the future. In conclusion, we developed our first hidden pattern film mood lamp by discovering new design factors other than optical pattern optimization. As a result of improving each factor and overcoming the limitations of existing design standards, we succeeded in economically mass-producing competitive consumer appeal items. Further research is underway by expanding the area of lighting design, which will be completed with the ability to develop mood lamps of various designs in the future.

Mr. HyeonCheol Cho, Researcher, Hyundai Motor Company