基于DMD的超短焦微型投影镜头设计

Design of ultra-short focal miniature projection lens based on DMD

  • 摘要: 针对现有的大多数超短焦投影设备成本高、体积大、垂轴色差和畸变校正困难等问题,设计了一款基于DMD芯片的超短焦微型投影镜头,并对其进行了公差分析和热分析。该系统由7片镜片组成,大大简化了结构并降低了成本。系统的F数为1.7,焦距为1.65 mm,系统总长79.39 mm,投射比达到0.16,具有大孔径、大视场、小型化等特点。设计结果表明:系统全视场的调制传递函数(MTF)在空间截止频率93 lp/mm处均大于0.65,接近衍射极限;系统的垂轴色差控制在1.2 μm以内,最大畸变为−2.17%,全视场相对照度大于0.95,满足设计要求。

     

    Abstract: In order to solve the problems of high cost, large volume, vertical color difference and distortion correction for most existing ultra short focal projection equipment,an ultra-short focal micro projection lens based on DMD (digital micro-mirror device) chip was designed, and its tolerance analysis and thermal analysis were carried out. The system consists of 7 lenses, greatly simplifying the structure and reducing the cost. The F number of the system is 1.7, the focal length is 1.65 mm, the optical length is 79.39 mm, the projection ratio is 0.16, and the system has the characteristics of large aperture, large field of view and miniaturization. The design results show that the MTF (modulation transfer function) of the full field of view is larger than 0.65 at the space cutoff frequency of 93 lp/mm, which is close to the diffraction limit. The vertical color difference of the system is controlled within 1.2 μm, the maximum distortion is −2.17%, and the full-field relative illuminance is greater than 0.95, which satisfy the design requirements.

     

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