Apparatus and method for electro-optical split image focusing

1. A split image focusing apparatus, comprising at least one electro-optical element disposed along an optical axis between a subject and a photographed plane, wherein the at least one electro-optical element is characterized by a refractive index that varies continuously with distance along a perpendicular to the optical axis when a voltage is applied, and through which an image of the subject is transmitted toward the photographed plane.

2. The split image focusing apparatus of claim 1 , wherein the at least one electro-optical elements comprises two electro-optical elements disposed in a position perpendicular both to each other and to the optical axis.

3. The split image focusing apparatus of claim 1 , further comprising:

a voltage value controller that changes the voltage applied to the at least one electro-optical element in response to a change in an aperture ratio.

4. The split image focusing apparatus of claim 1 , further comprising:

a photographing device disposed on the photographed plane on which light emitted from the subject is formed and converted into an electrical signal;

an image-plane deviation position detector that receives the electrical signal and calculates a deviation in the position of a focusing lens and generates an image-plane-deviation signal;

a focusing lens driving controller that drives a motor attached to the focusing lens along the optical axis; and

a driving position calculator that receives the image-plane-deviation signal and supplies a motor-driving signal to the motor.

5. The apparatus of claim 1 , further comprising a voltage polarity controller that changes a polarity of the voltage applied to the at least one electro-optical element based on a relationship between how a focusing lens moves along the optical axis and a direction of a manual operation of moving the focusing lens.

6. The split image focusing apparatus of claim 1 , further comprising:

a photographing device disposed on the photographed plane on which light emitted from the subject is formed and converted into an electrical signal;

an image processor that synthesizes a first image that is generated due to the subject image on the photographed plane when a voltage is not applied to the image processor and a second image that is generated due to the subject image on the photographed image when a voltage is applied to the image processor; and

an image display controller that displays the image that is synthesized by the image processor on an image display unit.

7. The split image focusing apparatus of claim 6 , wherein the image processor synthesizes the first image and the second image by moving a predetermined amount of a relative position of a plurality of regions in the second image.

8. The split image focusing apparatus of claim 6 , further comprising:

an aperture ratio obtaining unit that obtains an aperture ratio of a lens that images the image of the subject on the photographed plane; and

a voltage value controller that adjusts the voltage applied to the at least one electro-optical element based on the obtained aperture ratio.

9. The split image focusing apparatus of claim 6 , wherein a predetermined correction operation is performed on the image formed on the photographed plane from light transmitted through the at least one electro-optical element.

10. The split image focusing apparatus of claim 1 , further comprising:

a means for changing the voltage applied to the at least one electro-optical element in response to a change in an aperture ratio.

11. The split image focusing apparatus of claim 1 , further comprising:

a means for converting light incident to the photographed plane into an electrical signal;

a means for receiving the electrical signal and calculating a deviation in the position of a focusing lens and generates an image-plane-deviation signal;

a means for focusing a lens by receiving the image-plane-deviation signal and supplying a motor-driving signal to the motor.

12. The apparatus of claim 1 , further comprising:

a means for changing a polarity of the voltage applied to the at least one electro-optical element based on a relationship between how a focusing lens moves along the optical axis and a direction of a manual operation of moving the focusing lens.

13. The split image focusing apparatus of claim 1 , further comprising:

a means for converting light incident to the photographed plane into an electrical signal;

a means for image processing and synthesizing a first image that is generated due to the image of the subject on the photographed plane when a voltage is not applied to the image processor and a second image that is generated due to the image of the subject on the photographed image when a voltage is applied to the image processor; and

a means for displaying an image received from the means for image processing and synthesizing on an image display unit.

14. A method for split image focus photography in a device having at least one electro-optical element disposed along an optical axis between a subject and a photographed plane, wherein the at least one electro-optical element is characterized by a refractive index that continuously varies with distance along a perpendicular to the optical axis when a voltage is applied, and through which an image of the subject is transmitted toward the photographed plane, the method comprising:

converting light transmitted through the electro-optical element and emitted from the subject into an electrical signal by using photoelectrical conversion, wherein the converting is performed by a photographing device disposed on the photographed plane on which the light transmitted through the electro-optical element and emitted from the subject is formed as an image;

detecting an image-plane-deviation position of the image of the subject on the photographed plane that is generated by refraction in the optical element, and based on the electrical signal;

controlling driving of a focusing lens that moves in a direction of an optical axis and focuses the image of the subject on the photographed plane; and

calculating a driving position of the focusing lens based on the detected image-plane-deviation position.

15. The method for split image focus photography of claim 14 , further comprising:

changing the voltage applied to the at least one electro-optical element in response to a change in an aperture ratio.

16. The method for split image focus photography of claim 14 , further comprising:

converting light incident to the photographed plane into an electrical signal;

receiving the electrical signal and calculating a deviation in the position of a focusing lens and generates an image-plane-deviation signal;

focusing a lens by receiving the image-plane-deviation signal and supplying a motor-driving signal to the motor.

17. The method for split image focus photography of claim 14 , further comprising:

changing a polarity of the voltage applied to the at least one electro-optical element based on a relationship between how a focusing lens moves along the optical axis and a direction of a manual operation of moving the focusing lens.

18. The method for split image focus photography of claim 14 , further comprising:

converting light incident to the photographed plane into an electrical signal;

processing and synthesizing a first image that is generated due to the image of the subject on the photographed plane when a voltage is not applied to the image processor and a second image that is generated due to the image of the subject on the photographed image when a voltage is applied to the image processor; and

displaying an image received from the means for image processing and synthesizing on an image display unit.