潛望鏡

潛望鏡（Periscope），是一種利用光線反射原理所製作的光學儀器，最常被用在潛水艇用以在水下觀察水面上的動靜。曾在塹壕戰中被用來從壕溝觀察敵軍動態。潛望鏡並非只有軍事用途，過往雙層巴士亦有裝置潛望鏡，讓坐在下層的司機可觀察上層的情況，雙層巴士的潛望鏡至2000年代才逐漸由閉路電視取代^[1]。

Military handheld periscope optical design.
1 - Eyepiece
2 - Diagonal prism
3 - Handle
4 - 6 - Erecting lenses
5 - Periscope tube
7 - Field lens
8 - Lens
9 - Head diagonal prism
10 - Window

潛望鏡示意圖
Principle of the periscope.
A - Periscope using two plane mirrors.
B - Periscope using two right–angled prisms.
1 - 2 - Plane mirrors.
3 - 4 - Right–angled prisms.
5 - 6 - Observer eye.
7 - 8 - Periscope tube.
H - Periscope optical height.

Principle of the lens periscope.

A - Periscope using a single lens (L2) to correct image.

B - Periscope which uses two lenses (L2-L3) to correct image.

1-3 - Periscope window.

2-4 - Field stop or reticle.

P - Right–angled prisms (or plane mirrors).

L1 - Objective lens.

L2 - for A - L2 - L3 - for B - Image erecting lens.

L3 - L4 -for A - L4-L5- for B - Eyepiece.

L0 - Field lens.

y - Distant object.

H - Periscope optical height.

• 
  Submarine monocular attack periscope.
• 
  Zeiss submarine periscope optical design.

圖片

海軍使用潛望鏡

• 
  Officer at periscope in control room of a U.S. Navy submarine in World War II. The officer pictured is Captain Raymond W. Alexander, Sr. and the photo was taken in 1942.
• 
  Submarine monocular attack periscope
• 
  Torpedoed Japanese destroyer Yamakaze（英語：Japanese destroyer Yamakaze (1936)） photographed through periscope of USS Nautilus( USS Nautilus (SS-168)), 25 June 1942.

另見

• 望遠鏡
• 內視鏡
• 光電桅杆