Converter lens and imaging device

Abstract

To achieve reduction in size, high versatility, and high image quality.SOLUTION: A converter lens is a converter lens which is arranged on an image surface side with respect to an image-formation optical system and re-forms an image formed by the image-formation optical system and includes a plurality of lenses including at least one single lens or at least one cemented lens. The plurality of lenses include a first single lens or a first cemented lens arranged on the most object side in the converter lens. The surface on the object side of the first single lens or the first cemented lens is arranged in a position closer to the object side than the primary image-formation point of the image-formation optical system. The primary image-formation point exists outside the plurality of lenses constituting the converter lens. The converter lens satisfies a predetermined conditional expression.SELECTED DRAWING: Figure 1

Claims

1. A converter lens positioned on the image plane side of an imaging optical system, which re-images the image formed by the imaging optical system, It comprises multiple lenses, including at least one single lens or at least one cemented lens, The plurality of lenses include a first single lens or a first cemented lens positioned furthest towards the object within the converter lens. The object-side surface of the first single lens or the first cemented lens is positioned closer to the object than the primary imaging point of the imaging optical system. The primary imaging point is located outside the plurality of lenses that constitute the converter lens. The following conditions must be met: Converter lens. 0.01 ≤ da / db ≤ 0.175 ……(1) 0.01 ≤ dc / db ≤ 0.165 ……(2) -5.0 ≤ db / f1 ≤ 5.0 ……(3) -1.0 ≤ f3 / db ≤ -0.01 ……(5) however, da: Distance from the vertex of the object side of the first single lens or the first cemented lens to the primary image point. db: Distance from the vertex of the object's side surface to the secondary image point of the first single lens or the first cemented lens. dc: Distance from the vertex of the lens surface closest to the primary imaging point to the primary imaging point. f1: The focal length of the lens group of the converter lens, which is positioned closer to the object than the primary image point. f3: The focal length of the lens positioned closest to the image plane in the converter lens. Let's assume that.

2. The plurality of lenses further comprises a second single lens or a second cemented lens positioned immediately after the primary image point. The following conditions must be met: The converter lens according to claim 1. 0.01 ≤ f² / db ≤ 5.0 ……(4) however, f2: Focal length of the second single lens or the second cemented lens Let's assume that.

3. The converter lens has an aperture diaphragm, and when the converter lens is mounted on the imaging optical system, the aperture diaphragm in the converter lens changes the F-number. The converter lens according to claim 1.

4. The vertical focal length and the horizontal focal length are different. The converter lens according to claim 1.

5. The system includes a converter lens positioned on the image plane side of the imaging optical system and re-imaging the image formed by the imaging optical system, and an image sensor that outputs an imaging signal corresponding to the optical image formed by the converter lens, The aforementioned converter lens is It comprises multiple lenses, including at least one single lens or at least one cemented lens, The plurality of lenses include a first single lens or a first cemented lens positioned furthest towards the object within the converter lens. The object-side surface of the first single lens or the first cemented lens is positioned closer to the object than the primary imaging point of the imaging optical system. The primary imaging point is located outside the plurality of lenses that constitute the converter lens. The following conditions must be met: Imaging device. 0.01 ≤ da / db ≤ 0.175 ……(1) 0.01 ≤ dc / db ≤ 0.165 ……(2) -5.0 ≤ db / f1 ≤ 5.0 ……(3) -1.0 ≤ f3 / db ≤ -0.01 ……(5) however, da: Distance from the vertex of the object side of the first single lens or the first cemented lens to the primary image point. db: Distance from the vertex of the object's side surface to the secondary image point of the first single lens or the first cemented lens. dc: Distance from the vertex of the lens surface closest to the primary imaging point to the primary imaging point. f1: The focal length of the lens group of the converter lens, which is positioned closer to the object than the primary image point. f3: The focal length of the lens positioned closest to the image plane in the converter lens. Let's assume that.

6. It also features lenses that have virtually no refractive power. A converter lens according to any one of claims 1 to 4.

7. The converter lens further comprises a lens that has substantially no refractive power. The imaging apparatus according to claim 5.

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