| 摘要 |
<p>A ZOOM LENS SYSTEM HAVING TWO LENS GROUP (I, II). THE ZOOM LENS SYSTEM HAS A ZOOMING RATIO GREATER THAN 2.4, A VIEWING ANGLE OF OVER 70 DEGREES AND A TELEPHOTO RATIO OF ABOUT 1.0. THE ZOOM LENS SYSTEM INCLUDES A FIRST LENS GROUP (I) OF A POSITIVE REFRACTIVE POWER, WHICH HAS FOUR LENSES (1,2,3,4), AND A SECOND LENS GROUP (II) OF A NEGATIVE REFRACTIVE POWER, WHICH HAS THREE LENSES (5,6,7). THE SECOND LENS GROUP (II) INCLUDES ONE ASPHERICAL LENS SURFACE. THE ZOOM LENS SYSTEM ACCORDING TO THE PRESENT INVENTION SATISFIES THE FOLLOWING CONDITIONS: 0.22 <L / T < 0.30 2.45 <FT / FW 0.74 <LL / (FT- FW) < 0.85 0.75 <FL / Y< 1.10 WHERE FL IS A FOCAL LENGTH OF A FIRST LENS GROUP; FT IS A FOCAL LENGTH OF THE ENTIRE ZOOM LENS SYSTEM AT A TELEPHOTO POSITION; FW IS A FOCAL LENGTH OF THE ENTIRE ZOOM LENS SYSTEM AT A WIDE ANGLE POSITION; LLL IS A SHIFT DISTANCE OF THE FIRST LENS GROUP DURING ZOOMING; AND 2Y IS A DIAGONAL LENGTH OF AN IMAGE.</p> |
