投影顯示器鏡頭偏移調整結構分析之研究

Abstract

投影機的運用也普及各種環境的應用，有隨身攜帶的微投影、家庭休閒用的家庭劇院、大型場合的專業應用的投影機、專業劇院用投影機、教學會議用投影機…等，凡此應用時無不需要穩定的固定機構，大部分的投影機利用梯形修正以電子方式來修正梯形變易，但相對也犧牲了解析度，只有少部分高單價產品以光學方式作鏡頭偏移，不但可輕鬆將畫面調到所需螢幕位置，且不用犧牲解析度，但此方式因結構複雜，精度要求高且成本相對不便宜。 本研究以光學鏡頭偏移為研究對象，從光學、機構、電子及熱影響四個面向進行分析，包含鏡頭的解析度(Resolution)、調制傳遞函數(MTF=Optical transfer function)精度、結構強度、滑動精度、傳動扭力設計與效率、馬達的選擇和電流控管來探討最佳化設計，並試圖尋求兼具穩定性、信賴性與低成本之光學鏡頭偏移模組。 最後以實作樣品作實物進行以下驗證： 1.驅動實驗︰確認結構操作的穩定性，及預期動作的完成。 2.高低溫測試：確認於高低溫狀態，材料尺寸變化是否會影響預期動作。 3.衝擊測試驗：確認結構強度，防止因落下或衝擊影響到預期動作。 4.耐久實驗驗證：確認長期運動，是否會因磨耗或原件壽命影響結構整 以確認調整結構的穩定性，安全性及耐久性的可靠度。

The projector was used in popular environments: pocket projectors, Home Theaters, Professional Projectors in big party, Professional Theaters, teaching and business projectors...etc. Most of them have to be fixed in stable way. But they are not easy to fix the keystone effect to center to the screen . Most of the projectors were modified the keystone by electronic adjust, but it will reduce the resolution. Lens shift has designed into some high end model which could adjusted the screen position easier without reduce resolution. But the structure of lens shift not only complicated, high cost but also must be accuracy. This research analysis the lens shift structure with optical, mechanical, electronic and thermal, include resolution and MTF of Lens, structure stress, shift accuracy, torque efficiency, motor selection, position sensor control, current control and thermal expansion to optimize the design to get lens shift module more stable, safety, reliability and low cost. Finally, this research will test by really sample at follow item to confirm the stable, safety and reliability of the structure. 1. Make sure the working performance. 2. High low temperature to make sure the performance. 3. Make sure the structure by drop and vibration. 4. Life test to find out latent problem.