| 摘要 |
<p>1,273,002. Optical apparatus. P. MALIFAUD. June 12, 1969 [June 12, 1968], No.29930/69. Heading G2J. A convergent optical system concentrating a light beam on a sensitive element 5 comprises a front optical system 1 of relative aperture 1/N which forms an image of the source in its focal plane 2 at which the rays subtend a half angle # 1 at the optical axis (where # 1 = 1/2N and at least one substantially frusto-conical element 4 of internal refractive index n 1 and of apex half angle y which converges the beam by internal reflection on to the sensitive element 5 immersed in a medium of refractive index n 2 , the entry section of the frustoconical element 4 having a diameter d, coincident with the image and the exit section of said element 4 having a smaller diameter d 3 associated with the medium of refractive index n 2 and element 5, and wherein:- SIN# o = SIN# 1 /n 1 ; # o being the half angle of the rays entering the frusto-conical element 4 after refraction at d 1 ; SIN# = n2/n1 where # is the total reflection angle from n 1 to n 2 ; and n<SP>1</SP> equals the ratio of flux at the exit section to the entry section of element 4. The frusto-conical element 4 may be a hollow mirror, or a solid refracting glass body or a single or plurality of frusto-conical optical fibres. Preferably the sensing element 5 is located in a refracting glass of same refractive index as the frusto-conical element 4.</p> |
