• Journal of Korean Ophthalmic Optics Society
• /
• v.15 no.3
• /
• pp.247-255
• /
• 2010

Purpose: Developing a roofed Pechan prism type scope with long eye relief. Methods: To reduce the overall length and to lengthen the eye relief of scope, the objective part was designed by adopting the roofed Pechan prism and also the eyepiece part was designed by adopting the field lens with minus refractive power in front of reticle, respectively. Finally, by integrating above two parts, the roofed Pechan prism type scope with 90 mm eye relief was developed. Results: The characteristics of the developed and fabricated scope with 90 mm eye relief by integrating the objective part with the roofed Pechan prism and the eyepiece part with minus refractive power had the magnification of $+3.0{\times}$, the length from the 1st lens to the last lens of about 121 mm, the barrel diameter of 28 mm, and the effective objective-diameter of 17 mm. Also it was found that the line width of resolution was about 900 cycles/rad at the 50% MTF value criterion. Conclusions: We could design and manufacture the roofed Pechan prism type scope with 90 mm eye relief, the characteristics of which had the magnification of $3.0{\times}$, the MTF above 50% at 900 cycles/rad, and the length from the 1st lens to the last lens of about 121 mm.

• Journal of the Korea Convergence Society
• /
• v.7 no.6
• /
• pp.199-203
• /
• 2016

This study relates to the development of a program for calculating the roofed pechan prism design data. First, we set the roofed pechan prism design variables and derive the relational expressions between them. With this expressions, we could develope the program that outputs the numerical data for roofed pechan prism design when the face-length and the effective incident beam diameter are given. In fact, applying this program to the prism which is not the commercial size, we were able to calculate the design data very quickly, so that we can easily acquire the 3D structure of the actual roofed pechan prism. This means that we can quickly ensure the structural data of roofed pechan prism which is required for the product development and we are able to develop the new products related to the scope at a faster speed.