Aerial displays for providing road information require long-distance image formation and a compact installation space. This paper proposes a compact optical system for forming long-distance floating images by introducing a Fresnel lens in an aerial imaging by retro-reflection (AIRR) optical system. In the conventional AIRR optics, since the aerial image position is the plane-symmetrical position of the light source with respect to the beam splitter, the installation space for forming a long-distance aerial image becomes huge. Our proposed method uses the virtual image formed by a Fresnel lens as the light source in an AIRR optical system. This leads to a much longer distance from the beam splitter to the aerial image than the distance from the beam splitter to the light source. We developed a prototype long-distance floating aerial display system using a large-scale Fresnel lens. As a result, the distance from the LED panel to the beam splitter was halved. Furthermore, we used two beam splitters to form two aerial images by using a single LED panel. Long-distance floating images could be formed 3.4 m and 4.6 m away from the beam splitters and could be seen with the naked eye.

用于提供道路信息的航拍显示器需要长距离成像和紧凑的安装空间。本文提出了一种紧凑的光学系统，通过在逆反射航空成像（AIRR）光学系统中引入菲涅尔透镜来形成长距离浮动图像。在传统的AIRR光学器件中，由于空间图像位置是光源相对于分束器的平面对称位置，因此用于形成长距离空间图像的安装空间变得巨大。我们提出的方法使用菲涅耳透镜形成的虚像作为 AIRR 光学系统中的光源。这导致从分束器到空间图像的距离比从分束器到光源的距离长得多。我们开发了一种使用大型菲涅尔透镜的远距离浮动航空显示系统原型。结果，LED 面板到分光器的距离减半。此外，我们使用两个分束器通过单个 LED 面板形成两个航拍图像。距分光镜3.4 m和4.6 m处可形成肉眼可见的长距离浮动图像。