JP2594438B2 - Distance measuring device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION Object of the Invention (Industrial Application Field) The present invention relates to a distance measuring device used for a camera,
In particular, light for distance measurement is projected from the apparatus side toward the subject, and a reflected image from the subject is formed on a light receiving portion of the position detector by reflected light from the subject, and the reflected light from the subject is reflected by the reflected image. The present invention relates to a so-called active type distance measuring device that measures distance based on an output signal.

(Prior Art) FIG. 14 shows an example of a distance measuring optical system based on the principle of triangular distance measurement, wherein 1 is a light source, 2 is a position detecting element (position detector) such as a PSD, 3 is a light projecting lens, Reference numeral 4 denotes a light-receiving lens, which is used in this distance-measuring optical system by receiving the reflected light of the light emitted from the light source 1 from the subject as a distance-measuring light by the position detecting element 2. There is a relational expression between the distance U to the object and the amount of deviation t from the reference position on the position detecting element 2 as t = L · f / (U−f−d).

Here, L: Base line length between the light projecting lens 3 and the light receiving lens 4 f: Focal length of the light receiving lens 4 d: Distance between the film surface 5 and the focal plane of the light receiving lens 4 Reference position (shift amount t = 0) Is a position on the position detecting element 2 where a light source image is formed when the subject is positioned at an infinite distance ∞.

Since the shift amount t can be detected by the magnitude of the photocurrent of the position detecting element 2 as is well known, the distance U can be obtained from the above equation based on the amount of electricity. If the photographing lens is moved to the focal position based on the distance U, focusing is automatically performed. A drive mechanism for focusing such an autofocus camera is known.

(Problems to be Solved by the Invention) By the way, in this conventional automatic ranging device for a camera,
Since the distance measuring spot 6 is provided at the center of the viewfinder 7 as shown in FIG. 15, a desired subject 8 is located at the center of the photograph as it is, but the desired subject 8 is located at the center. There are times when you want to get a photo taken around the photo instead. Therefore, the conventional camera is provided with a focus lock mechanism in consideration of this fact, and the subject 8 is positioned at the center of the viewfinder 7 to automatically measure the distance to the subject 8, and in that state, the focus is adjusted. By locking and taking a picture by performing framing as shown in FIG. 16, it is possible to obtain a photograph in which a desired subject 8 is arranged around the periphery.

However, in this conventional automatic distance measuring device for a camera, the subject 8 is once positioned at the center of the viewfinder 7, the photographing lens is moved to a focused state, and the photographing lens is fixed by locking the focus in this state. There is a problem in that the photographing operation takes too much time because the photographing sequence of re-composing and photographing must be taken.

SUMMARY OF THE INVENTION An object of the present invention is to provide a camera distance measuring apparatus that can easily and quickly perform a photographing operation for obtaining a photograph in which a desired subject is arranged in a peripheral portion.

Configuration of the Invention (Means for Solving the Problems) In order to achieve the above object, the present invention projects a distance measuring light beam toward a subject, and reflects light from the subject to a light receiving unit of a position detector. In a distance measuring device that forms a reflection image from the subject and measures the distance of the subject based on an output signal of the position detector based on the reflection image, a plane portion that transmits reflected light to the subject side of the position detector. A pair of optical elements having a prism portion are provided, and the prism portions of the pair of optical elements each include a top portion and a valley portion, and at least one of the optical elements is movable in a parallel direction of the top portion and the valley portion of the prism portion. When the top and bottom of the prism portion of one optical element and the bottom and top of the prism portion of the other optical element come to oppose to each other due to the movement of the optical element, a single point is applied. The reflected image from the object is formed on the light receiving section of the position detector by the reflected light from the body, and the top and the valley of the prism section in one optical element and the prism in the other optical element are formed by the movement of the optical element. When the top and the valley of the part are at positions facing each other, the reflected images from the respective subjects are simultaneously formed on the light receiving part of the position detector by the reflected light from the plurality of subjects in a predetermined direction. Things.

Further, the present invention projects a light beam for distance measurement from one light source toward a subject, forms a reflected image from the subject on a light receiving unit of a position detector by reflected light from the subject, and In a distance measuring device that measures a distance of a subject based on an output signal of the position detector, a pair of optical elements having a plane portion and a prism portion that transmit a light beam for distance measurement are provided on the subject, and a pair of optical elements is provided. Each of the prism portions includes a top portion and a valley portion, and at least one of the optical elements is movable in a parallel direction of the top portion and the valley portion of the prism portion. When the valley portion and the valley portion and the top portion of the prism portion in the other optical element come to opposing positions, the light beam for distance measurement from the light source is projected onto one point of the subject, and the By moving
A top part and a valley part of a prism part in one optical element,
When the top and the valley of the prism section of the other optical element come to opposing positions, the light beam for distance measurement from the light source is simultaneously projected to a plurality of subjects in a predetermined direction.

(Embodiment) Hereinafter, an embodiment of a camera distance measuring apparatus according to the present invention will be described with reference to the drawings.

FIG. 1 is a layout view of the optical system in front of the camera, FIG. 2 is a plan view of the optical system as viewed from above the camera, and FIG. 3 is a layout view of the optical system as viewed from the side of the camera. Note that the same components as those in the conventional example are denoted by the same reference numerals, and description thereof will be omitted.

In the drawing, reference numeral 10 denotes a photographing lens system, which is controlled to move to a focus position based on an output signal output from the position detecting element 2 as in the related art. Reference numerals 11 and 12 denote a pair of opposing optical elements provided in front of the light projecting lens 3 and the light receiving lens 4, and are made of a porous material such as glass or plastic. Can move left and right. Also, the optical element
11 and 12 are flat parts at the position facing the upper half of each lens 3 and 4
Opposing prism portions 11a, 11b, 12a, and 12b are provided at positions where 11P and 12P face the lower half.
The angles of the peaks and valleys of the prism portions 11a and 11b are equal to the angles of the valleys and peaks of the prism portions 12a and 12b.

Therefore, when the optical element 11 is located at the tops and valleys of the prism portions 12a and 12b of the optical element 12 and the valleys and tops of the prism portions 11a and 11b face each other (see FIG. 4), Since the pair of optical elements 11 and 12 have the same function as an ordinary glass plate, the light for distance measurement from the light source 1 is transmitted through the light projecting lens 3 and the optical elements 11 and 12 as in the related art. The reflected light from the subject in the frontal direction is incident on the optical elements 11 and 12 and the light receiving lens 4 to form a reflected image from the subject on the light receiving portion of the position detecting element 2 as in the related art. You. The distance of the subject is measured by an output signal based on the position of the reflected image formed on the light receiving section. Then, the taking lens 10 is focused on the basis of the distance measurement.

The optical element 11 is slightly moved in the horizontal direction so that the tops and valleys of the prisms 11a and 11b are
When the ridges and valleys 2a and 12b are opposed to each other (see FIGS. 5 and 7), the light beam for distance measurement emitted from the light source 1 via the light projecting lens 3 is reflected by the prisms 11a and 12a of the optical elements 11 and 12. The light is projected in three directions, that is, the left-right direction (in FIG. 5) and the front direction by the flat portions 11P and 12P. When there are three subjects A, B, and C in these three directions, for example, as shown in FIG. 6, the projected distance measuring light beam is reflected by the subjects A, B, and C. When these reflected lights enter the prism portions 11b and 12b and the flat portions 11P and 12P of the optical elements 11 and 12 from three predetermined directions, respectively, as shown in FIG. Are formed at three different points (i.e., multipoint ranging is performed). Of these reflected images, the one due to the reflected light of the subject A located at the shortest distance causes a large output signal to be output from the position detection element 2, so that the photographic lens 11 is focused on the subject A.

That is, as shown in FIG.
Is projected in the direction of, and the taking lens 11 is focused on the subject A of the strongest reflected light by this projection.
It is not necessary to perform an operation such as positioning the subject A at the center of the viewfinder 7 to lock the focus and redetermining the composition as in the related art.

FIGS. 8 and 9 show a second embodiment, which is similar to the above-described prism units 21a, 21b, 22a, 22b in a camera in which the light projecting lens 3 and the light receiving lens 4 are installed horizontally. FIG. 10 shows an example in which optical elements 21 and 22 having planar portions 21P and 22P are applied, and the optical element 21 is formed with prisms 21a, 21b, 22a and 22b as shown in FIG. When the valleys are located at opposing positions, the light beam for distance measurement is projected in three directions in the same manner as described above.
Only the reflected light from these three directions is received by the position detecting element 2 via the optical elements 21 and 22 and the light receiving lens 4. FIG. 8 is a plan view of the optical system, and FIG. 9 is a front view thereof.

FIG. 11 shows a third embodiment, which is an optical element.
The upper and lower surfaces of the surfaces facing the lenses 3, 4 of 31, 32 are prism portions 31a, 31b, 32a, 32b, and the central portion of the surface is the flat portions 31P, 3P.
It is 2P, and is formed so that the apex angles of the upper prism portions 31a and 32a and the apex angles of the lower prism portions 31b and 32b are different from each other as shown in FIG. This prism part 31a, 31
b, 32a, 32b, two directions to the left and right, flat portions 31p, 32p
Luminous flux for distance measurement is projected in a total of 5 directions from the front direction by
Further, only the reflected light from the five directions is detected by the position detecting element 2.
Received.

FIG. 13 shows a fourth embodiment, in which three light sources 1 are arranged so that their optical axes 1a, 1b, 1c are oriented in three directions as shown in FIG. It is intended to be projected on. It should be noted that the light source 1 may be a single light source as long as the light source 1 spreads in the left-right direction and projects a light beam for distance measurement having a predetermined strength or more.

The means for moving the optical elements 11, 21, 31 in the above embodiment may be manual, solenoid, or any other means.
2, 32 may be moved.

Effects of the Invention As described above, according to the present invention, by moving at least one of a pair of optical elements, ranging from one-point ranging to multi-point ranging, and conversely, from multi-point ranging to one-point ranging. You can easily switch to the distance. As a result, it is possible to easily and quickly perform the photographing operation not only when photographing a single subject but also when photographing a plurality of subjects in a predetermined direction.

[Brief description of the drawings]

1 is a layout view of the optical system in front of the camera, FIG. 2 is a plan view of the optical system as viewed from the top of the camera, FIG. 3 is a layout view of the optical system as viewed from the side of the camera, FIG. 4 and FIG. And FIG. 7 is an explanatory view showing an incident state of reflected light and a projected state of a distance measuring light beam;
FIG. 6 is an explanatory view showing the position of the subject, FIGS. 8, 9 and 10 are explanatory views of the second embodiment, FIGS. 11 and 12
FIG. 13 is an explanatory view of the third embodiment, FIG. 13 is an explanatory view of the fourth embodiment, FIG. 14 is an explanatory view of the principle of triangulation, FIG. 15 and FIG.
FIG. 1 is an explanatory diagram showing a conventional relationship between a subject and a distance measuring spot. 2 Position detecting element 8, A Subject 10 Photographing lens 11, 12 Optical element 11a, 11b, 12a, 12b Prism section 11P, 12p Planar section

Claims (2)

(57) [Claims] 1. A distance-measuring light beam is projected toward a subject, a reflected image from the subject is formed on a light-receiving portion of a position detector by reflected light from the subject, and an output of the position detector based on the reflected image is formed. In a distance measuring device that measures a distance of a subject based on a signal, a pair of optical elements having a plane part and a prism part that transmit reflected light is provided on the subject side of the position detector, and the prism part of the pair of optical elements is Each consists of a top and a valley,
At least one of the optical elements is movable in a parallel direction of a top part and a valley part of a prism part, and the movement of the optical element causes a top part and a valley part of a prism part in one optical element and a prism in the other optical element. When the valley and the top of the part come to a position facing each other, a reflected image from the subject is formed on the light receiving section of the position detector by reflected light from the subject at one point, and by moving the optical element, When the peaks and valleys of the prism portion in the optical element and the peaks and valleys of the prism portion in the other optical element come to opposing positions, each subject is reflected by the plurality of subjects in a predetermined direction. A distance measuring device configured to simultaneously form a reflection image from the light-receiving portion of the position detector. 2. A distance measuring light beam is projected from one light source toward a subject, and a reflected image from the subject is formed on a light receiving portion of a position detector by reflected light from the subject, and the reflected image is formed by the reflected image. A distance measuring device for measuring a distance of a subject based on an output signal of a position detector, comprising: a pair of optical elements having a plane portion and a prism portion that transmit a light beam for distance measurement to the subject; The part is composed of a top and a valley, respectively, and at least one of the optical elements is movable in a parallel direction of the top and the valley of the prism part. By the movement of the optical element, the top of the prism part in one of the optical elements and When the valley and the valley and the top of the prism portion of the other optical element are located opposite to each other, the distance measuring light beam from the light source is projected onto a single object, and the optical element is moved. Accordingly, when the top and the valley of the prism portion of one optical element and the top and the valley of the prism portion of the other optical element come to opposing positions, the light beam for distance measurement from the light source is directed in a predetermined direction. A distance measuring device configured to simultaneously project light to a plurality of subjects.