JPH1096852A - Focus detector using two-dimensional imaging device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a focus detector using a two-dimensional imaging device which uses the two-dimensional imaging device, by which the detection of both longitudinal and lateral edges can be performed with one imaging device, also which can perform the range-finding of a large area, by which an object image is not required to be divided into two as the object image is divided into two with a phase difference system, by which data on the area of a photographing element can be efficiently utilized, and by which the same photographing element can use the data of the imaging device as not only AF but AE. SOLUTION: Micro lenses 3a having diameter including nine detection elements longitudinally and laterally arrayed on the two-dimensional CCD imaging device 4 are regularly arrayed. The data of the detection element on an optical axis part and the data of the detection element on four corners are not used, but the data on a longitudinal line detection element 7 and the data on a lateral line detection element 8 symmetrically arranged centering the optical axis are used. When the received light quantity of the detection elements of the respective lenses 3a in a symmetrical relation coincides each other, focusing is performed; and when the received light quantity of the detection elements in another positional relation coincides each other, that is front or rear focus.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a focus detecting device for recognizing an image forming position of light of a subject passing through a photographing lens and detecting a focus position of the subject. More specifically, the present invention can widen an AF ranging area. Also, the present invention relates to a focus detection apparatus using a two-dimensional image sensor which also simplifies an AF optical system.

[0002]

2. Description of the Related Art In an existing AF optical system capable of detecting both vertical and horizontal edges, AF detection has been performed for one fixed line. FIG. 4 shows one of the conventional examples, and is a diagram showing an example of a distance determining device for performing focus detection based on one line (Japanese Patent Publication No. 57-49841). Light from the subject is condensed by a condenser lens 21 and is projected through a fly-eye lens 22 onto a CCD element as a line sensor. On the line sensor, A elements and B elements are alternately arranged. Now, if the defocus amount is x,
Light passing through a point corresponding to a point on the optical axis of the camera as shown in FIG.
Incident on the light-receiving elements A and B belonging to the fly-eye lens where the point exists.

Similarly, all image points on the image plane of the camera lens are shifted by ± θx to form an image, and as a result, an image sampled by the element group A and an image sampled by the element group B are obtained. And are shifted laterally by 2θx. If the amount of lateral displacement is calculated by an arithmetic circuit and fed back to the amount of extension of the camera lens, auto focus is achieved. As a line sensor actually used, two sets of element rows for F4 and F2.8 are used as shown in FIG.

[0004]

In the above-mentioned prior art, since a line detection is mainly performed, a target as a distance measuring area has a drawback that the distance is measured by a line and can be measured only in a narrow range. When targeting a large area, it is necessary to bring the position of the subject to the line sensor position while shaking the camera. Further, the AF area is a line, and by the nature of the
/ AE was difficult to perform. The AE area cannot be set on the line sensor that is the AF area,
This is because the AE area is generally a surface area, and it is generally rare that the surface area completely matches the AF area.

[0005] An object of the present invention is to solve the above-mentioned problem, and to detect both vertical and horizontal edges by using a two-dimensional image sensor.
One image sensor enables distance measurement over a wide area, and there is no need to divide the subject image into two parts unlike the phase difference method. Area data can be used effectively on the image sensor, and only AF can be performed with the same image sensor. Another object of the present invention is to provide a focus detection device using a two-dimensional image sensor which can use data of the image sensor even as an AE.

[0006]

In order to solve the above-mentioned problems, a focus detection apparatus using a two-dimensional image pickup device according to the present invention recognizes an image forming position of light of a subject passing through a photographing lens and recognizes the position of the subject. In a focus detection device that detects a focus position, a large number of microlenses are provided on the surface of a two-dimensional imaging element in which detection elements are arranged in the vertical and horizontal directions, and the microlens forms an image on a predetermined number of detection elements. It has a lens diameter, and is arranged regularly so that the arrangement of the vertical line detecting element in the vertical direction and the horizontal line detecting element in the horizontal direction are respectively symmetrical with respect to the optical axis of the micro lens, and the optical axis of the micro lens Is a symmetrical position with respect to the center, the focus is set when the received light amounts of the adjacent detection elements match, and the focus is set to be out of focus when the received light amounts of the detection elements of other positional relationships match, and the micro lens is Each There are configured to capable of detecting vertical and horizontal both edges of the object by the detection device of the range to be imaged. The predetermined number of detection elements is nine, of which:
The configuration can be made using the light reception data of the other four detection elements excluding the light reception data obtained by a total of five detection elements at the optical axis center and each corner.

[0007]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a diagram schematically showing a focus detection device using a two-dimensional image sensor according to the present invention. The light from the subject with the condenser lens 1 on the film equivalent surface is
The light is collected and enters the relay lens 2. Relay lens 2
The subject light that has passed through is two-dimensional CCD by the lens array 3.
The image is projected on the image sensor 4. In an actual configuration, a reflection mirror is inserted between the condenser lens 1 and the relay lens 2, and the light to the relay lens 2 is changed in direction.

FIG. 2 is a diagram showing an example of the arrangement of each detection element and each microlens of the two-dimensional CCD image pickup element. The focal length 12 of the lens array 3 composed of a plurality of microlenses is a distance from the lens surface to the image sensor surface 5 of the two-dimensional CCD image sensor 4. Each detection element is arranged in the vertical and horizontal directions, and one set of nine detection elements constitutes an element 9 on which one microlens is arranged. Thereby, two vertical line detecting elements 7 and 2 are positioned around the detecting element at the position coincident with the optical axis of the microlens among the nine detecting elements.
The horizontal line detecting elements 8 are arranged. The two vertical line detection elements 7 are symmetrically positioned in the vertical direction about the optical axis, and the two horizontal line detection elements 8 are similarly symmetrically positioned in the horizontal direction.

Light reception data of one detection element at the center and four detection elements at four corners are not used. Vertical and horizontal edges can be detected for each set of nine elements, and these elements are arranged in a plane range. The data of the vertical line detecting element 7 and the data of the horizontal line detecting element 8 are sent to an arithmetic circuit section 13 for calculating a focus by scanning with a two-dimensional CCD image pickup element. The arithmetic circuit unit 13 performs an arithmetic operation to determine whether or not the amounts of light received by the detection elements at symmetrical positions about the vertical and horizontal axes corresponding to the microlenses coincide with each other. The arithmetic result is fed back to an AF mechanism (not shown). Is done.

FIG. 3 is a diagram showing an example in the case of front focus, in-focus, and back focus. When corresponding to the vertical direction, A
Reference numerals 1 and B1 denote vertical line detecting elements in a vertical symmetrical positional relationship corresponding to one microlens in FIG. A2
B2, A3, and B3 are also vertical line detecting elements that are symmetrical in the vertical direction corresponding to other microlenses. Similarly, when corresponding to the case of the horizontal direction, A1, B1 and A2, B2 and A3, B
3 is a horizontal line detecting element. At the time of focusing, as shown in (b), the amount of light received by A and B adjacent to each other around the optical axis of each microlens coincides.

In the case of the front focus, as shown in (a), the light reception amounts of the A and B detection elements of the light passing through different microlenses, that is, the light reception amounts of the non-adjacent A and B detection elements coincide. . In the case of the rear focus, as shown in (c), the detection elements having the same amount of received light are adjacent to each other, but the light incident on the adjacent detection elements is light passing through different microlenses. . Since the amounts of light received by the detection elements A and B do not actually match exactly, the arithmetic circuit unit 13 selects the detection element having the smallest difference in the amount of received light by calculation. When performing AF, the received light data of each detection element of the two-dimensional CCD image sensor is used as described above, but AE can be performed using the output of each detection element of the two-dimensional CCD image sensor. In this case, the AE area is a two-dimensional CCD
The entire surface of the image sensor can be set as the AE range to match the AF range, or a partial area of the surface of the two-dimensional CCD image sensor can be set as the AE range.

[0012]

As described above, according to the present invention, a large number of microlenses are provided on the surface of a two-dimensional image pickup device in which detection elements are arranged in the vertical and horizontal directions, and the microlenses form an image on a predetermined number of detection elements. Having a lens diameter such that the arrangement of the vertical vertical line detecting element and the horizontal horizontal line detecting element are regularly arranged so as to be respectively symmetrical with respect to the optical axis of the microlens. When the light receiving amounts of the adjacent detecting elements are symmetrical with respect to the optical axis and the received light amounts of the adjacent detecting elements match, focusing is performed, and when the light receiving amounts of the detecting elements of other positional relationships match, defocusing is performed. Are configured so that both the vertical and horizontal edges of the subject can be detected by the detection elements in the range where each of them forms an image. Therefore, both vertical and horizontal edges, which cannot be detected by a single sensor in the related art, can be detected, and the detection can be performed in a wide area without dividing into two as in the phase difference method. 2 images of the subject
Since it is not divided, the optical system for AF becomes simpler, and the area equivalent to twice the distance measurement area on the film equivalent surface on the image sensor is not used. To be able to make the most of it.
In addition, since AE can be performed by the two-dimensional image pickup device, there is an effect that the two-dimensional CCD image pickup device can be used more effectively.

[Brief description of the drawings]

FIG. 1 is a diagram schematically showing a focus detection device using a two-dimensional imaging device according to the present invention.

FIG. 2 is a diagram showing an example of the arrangement of each detection element and each microlens of a two-dimensional CCD image pickup element.

FIG. 3 is a diagram illustrating an example of front focus, in-focus and back focus.

FIG. 4 shows one of the conventional examples, and is a diagram showing an example of a distance determination device for performing focus detection based on one line.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Condenser lens 2 ... Relay lens 3 ... Lens array 4 ... 2D CCD imaging element 7 ... Vertical line detection element 8 ... Horizontal line detection element 9 ... Element 1 set 10 ... Pair of element intervals 11 ... 1 set pitch 12 ... Lens array Focal length

Claims (2)

[Claims] 1. A focus detecting device for recognizing an image forming position of light of a subject passing through a photographing lens and detecting a focus position of the subject, wherein a large number of detecting elements are arranged on a surface of a two-dimensional image pickup device arranged in a vertical and horizontal direction. A microlens is provided, the microlens has a lens diameter such that an image is formed on a predetermined number of detection elements, and an arrangement of a vertical vertical line detection element and a horizontal horizontal line detection element is the light of the microlens. Are arranged regularly so as to be respectively symmetrical about the axis, and are symmetrical about the optical axis of the microlens,
When the received light amounts of the adjacent detectors match, focus is set,
When the light receiving amounts of the detecting elements in other positional relations coincide with each other, the focus is determined to be out of focus, and the vertical and horizontal edges of the subject can be detected by the detecting elements in the range where each of the micro lenses forms an image. A focus detection device using a characteristic two-dimensional image sensor. 2. The light receiving data of four other detecting elements excluding the light receiving data obtained by a total of five detecting elements at the center of the optical axis and at each corner of the nine detecting elements. 2. A focus detection device using a two-dimensional image sensor according to claim 1, wherein: