Optical design of head-mounted projective display for vein imaging

A novel head-mounted projective display (HMPD) for vein imaging is proposed in this paper. The correspondent optical system is designed, which consists of imaging system and see-through HMPD. The infrared imaging system has a large numerical aperture with F number of 2.6, which is extremely conducive to receive and to image the weak reflected near-infrared light from the patient's skin surface. The resolution of the imaging system is QXGA (2048 x 1536). The see-through HMPD possesses an 18mm exit pupil and a 25mm eye relief, with ultra-light in weight, compact in structure and comfort in wearing. Meanwhile, it has a satisfactory performance for vein imaging that the field curvature is less than 0.03D, the distortion is less than 0.32% and the resolution is up to QXGA. The structure of the optical system of HMPD is consistent to that of infrared imaging part, which is conducive to simplify the processing and assembly in manufacture. The proposed visual instrument for vein display is suitable for supplementing existing venipuncture techniques.