Visible and infrared light photographing lens system
The present invention provides a visible and infrared light photographing lens system. A color separating prism or the like divides an object light entering a photographing lens and then passing through a focus lens, into an object light in a visible light region and an object light in an infrared light region. A visible light image pickup element and an infrared light image pickup element are used to pick up images of the respective object lights. Further, a compensation lens can be used to adjust a position where an image of the object light in the infrared light region is formed. Consequently, visible light photographing and infrared light photographing can be simultaneously carried out by focusing on an object at the same distance.
1. A visible and infrared light photographing lens system which enables the same object to be photographed simultaneously using a visible light and an infrared light, the system comprising:
a focus lens which can be moved in a direction of an optical axis in order to focus on the object at a desired object distance;
a light dividing device which divides an object light having passed through said focus lens, into an object light for a visible light and an object light for an infrared light and which guides the object light for the visible light and the object light for the infrared light through a visible light optical path and an infrared light optical path, respectively;
a visible light image pickup device which picks up an object image of a visible light using the object light for the visible light;
an infrared light image pickup device which picks up an object image of an infrared light using the object light for the infrared light;
a compensation lens placed in at least one of the visible light optical path and the infrared light optical path so as to be movable in the direction of the optical axis, the compensation lens adjusting a position at which the object light passing through the compensation lens is formed into an image; and
a compensation lens control device which determines an amount of compensation of a focusing position of infrared light on the basis of a position of an iris and position of the focus lens so that an object distance to the object at which said visible light image pickup device can be focused on the object is equal to an object distance to the object at which said infrared light image pickup device can be focused on the object.
2. The visible and infrared light photographing lens system according to claim 1 , further comprising a zoom lens in front of said light dividing device, the zoom lens being movable in the direction of the optical axis in order to vary a zoom magnification, wherein said compensation lens control device controls the position of said compensation lens on the basis of a position of said focus lens and a position of said zoom lens.
3. The visible and infrared light photographing lens system according to claim 1 , wherein said light dividing device is a dichloic mirror or a color separating prism, and a spectrum is obtained on the basis of wavelength regions by setting the object light for said visible light to be an object light in a visible light region and setting the object light for said infrared light to be an object light in an infrared light region.
4. The visible and infrared light photographing lens system according to claim 2 , wherein said light dividing device is a dichloic mirror or a color separating prism, and a spectrum is obtained on the basis of wavelength regions by setting the object light for said visible light to be an object light in a visible light region and setting the object light for said infrared light to be an object light in an infrared light region.
5. The visible and infrared light photographing lens system according to claim 1 , wherein an iris is placed in each of said visible light optical path and said infrared light optical path through which the object light for the visible light and the object light for the infrared light, respectively, into which the object light has been divided by the light dividing device, are guided.
6. The visible and infrared light photographing lens system according to claim 2 , wherein an iris is placed in each of said visible light optical path and said infrared light optical path through which the object light for the visible light and the object light for the infrared light, respectively, into which the object light has been divided by the light dividing device, are guided.
7. The visible and infrared light photographing lens system according to claim 1 , wherein an iris is placed in front of said light dividing device.
8. The visible and infrared light photographing lens system according to claim 2 , wherein an iris is placed in front of said light dividing device.
9. The visible and infrared light photographing lens system according to claim 1 , wherein the iris is placed in front of said light dividing device, and a light quantity adjusting device is placed in both or one of said visible light optical path and/or said infrared light optical path through which the object light for the visible light and/or the object light for the infrared light, respectively, into which the object light has been divided by the light dividing device, is/are guided.
10. The visible and infrared light photographing lens system according to claim 2 , wherein the iris is placed in front of said light dividing device, and a light quantity adjusting device is placed in both or one of said visible light optical path and/or said infrared light optical path through which the object light for the visible light and/or the object light for the infrared light, respectively, into which the object light has been divided by the light dividing device, is/are guided.