JPH0128407Y2 - - Google Patents

Description

[Detailed description of the invention] The present invention is a camera distance measuring device, more specifically,
Relating to a so-called projector-type distance measuring device in which the camera emits a beam of light for distance measurement toward the subject, and the camera receives the reflected light of this beam again to measure the distance to the subject. .

A beam of light for distance measurement is directed toward the subject, and the reflected light is received to measure the distance to the subject.
A distance measuring device for a so-called floodlight camera is already well known. However, in conventional distance measuring devices of this type, the light beam for distance measurement is emitted from a light projection window provided on one side of the front of the camera body toward the subject almost parallel to the photographing optical axis. Therefore, the light-receiving window provided on the other side of the front surface of the camera body receives a reflected beam of light in the direction of the optical axis that is considerably inclined with respect to the photographing optical axis. Therefore, there is a parallax between the photographing optical system and the distance measuring optical system, and this parallax causes an error in the measured distance, and in some cases, it may be difficult to measure the distance to a subject other than the desired one. There was a fear that it would be measured.

The purpose of the present invention is to eliminate the above-mentioned drawbacks of the conventional technology by sequentially changing the irradiation direction of the distance-measuring light beam and changing the light-receiving direction of the light-receiving device accordingly. An object of the present invention is to provide a distance measuring device for a camera in which parallax does not occur between a distance measuring optical system and a distance measuring optical system.

According to the present invention, since the parallax between the photographing optical system and the distance measuring optical system is removed, measurement errors due to this parallax are eliminated, and distances to objects other than the desired object can be measured. There will be no fear.

The present invention will be explained below based on the illustrated embodiments.

FIG. 1 shows a camera equipped with the distance measuring device of the present invention. This camera 1 has a camera body 2
A photographing lens barrel 3 is protruded from the center of the front surface of the camera, and a photographing lens 4 is disposed within the lens barrel 3. In addition, on the front side of the camera body 2, there is a light projection window 5 that emits a beam of light for distance measurement across the photographic lens barrel 3, and a light receiving window that receives the beam of light reflected from the subject 9 (see Fig. 2). A window 6 is provided respectively. The height of the center of the light emitting window 5 and the light receiving window 6 coincides with the height of the main optical axis O of the photographing lens 4 (see FIG. 2). The distances L ₁ and L ₂ (see FIG. 2) from the main optical axis O to the centers of the windows 5 and 6 are also selected so as not to differ greatly. In FIG. 1, the reference numeral 7 indicates a finder objective window, and the reference numeral 8 indicates a shutter release button which also serves as a distance measurement command operating member of the present distance measurement apparatus.

Corresponding to the light projection window 5, an optical path changing mirror 11 as shown in FIG. 2 is provided as means for changing the direction of irradiation of the distance measuring light beam. The optical path changing mirror 11 is arranged to be rotatable about a central axis in the vertical direction, and by rotating about the same axis, the optical path changing mirror 11 is moved from the side toward the center of the camera body 2. The incoming distance measuring light beam is reflected toward the subject 9 while sequentially changing the irradiation direction. A light emitting element 12 as a light source device and a condensing lens 13 are disposed on the side of the optical path converting mirror 11 near the center of the camera body 2, which generates a beam of light for distance measurement. The light emitting element 12
For example, a light emitting diode, a semiconductor laser, etc. are used. The light emitted from the light emitting element 12 is focused by the condensing lens 13 into a beam of light for distance measurement, and is incident on the optical path changing mirror 11 .

On the other hand, a light receiving lens 14 shown in FIG. 2 is disposed corresponding to the light receiving window 6. A photoelectric conversion element array 15 as a light receiving device is arranged behind the light receiving lens 14 and receives the distance measuring light beam reflected by the subject 9. This photoelectric conversion element array 15 is formed by arranging a plurality of (four in the figure) photoelectric conversion elements 15a to 15d, and includes the optical path changing mirror 1.
In synchronization with the rotation of 1, the photoelectric conversion elements 15a to 15
d is configured to sequentially and selectively enter the light-receiving state.

If the horizontal direction perpendicular to the principal optical axis O of the photographic lens 4 is the base line direction, and the angle between this base line direction and the irradiation direction of the light ray bundle is the irradiation angle θ, then the ray bundle will be directed from the direction where the irradiation angle θ is large to the direction where the irradiation angle θ is small. The object 9 is irradiated while the irradiation direction is sequentially changed, and the object 9 is scanned. Therefore, the light beam passes through the irradiation optical path l ₁ when the irradiation angle θ is the largest (θ = θ ₁ ), and as the irradiation angle θ becomes smaller (θ = θ ₂ , θ ₃ , θ ₄ ) Therefore,
The light passes sequentially through irradiation optical paths l ₂ , l ₃ , and l ₄ . Each of the optical paths l ₁ to l ₄ intersects the main optical axis O at points P ₁ to P ₄ , and each of these points P ₁
~ _P4 are located in the direction desired by each of the photoelectric conversion elements 15a to 15d of the photoelectric conversion element array 15 through the light receiving lens 14, respectively. In other words, in the photoelectric conversion element array 15, the photoelectric conversion element 15a that looks at the farthest point _P1 is located at the center of the camera body 2, and the photoelectric conversion element 15d that looks at the nearest point _P4 is located at the side of the camera body 2. If the angle between the base line direction and the desired direction of the photoelectric conversion elements 15a to 15d is the light receiving angle, then the light receiving optical path l ₁ ′ in the desired direction of the photoelectric conversion elements 15a to 15d is
For l ₄ ′, the acceptance angle becomes smaller ( ₁ > ₂ > ₃
> ₄ ) It is becoming like this.

Note that the light receiving direction switching means for selectively bringing the photoelectric conversion elements 15a to 15d into the light receiving state in accordance with the rotation of the optical path changing mirror 11 can be easily formed by known technical means. .

In this manner, the camera distance measuring device of the present invention is configured.

Next, the operation of this distance measuring device will be explained.

First, when the shutter release button 8, which also serves as a distance measurement command operation member, is pressed, the light emitting element 12 is turned on based on this, and a beam of light for distance measurement is generated. Due to the rotation, the object 9 is irradiated while successively passing through irradiation optical paths l ₁ to l ₄ . Now, subject 9 is point P ₂
If the ray bundle is located at a distance D of
When passing through l ₁ , the reflected light beam reflected by the subject 9 does not enter the photoelectric conversion element 15a which is in the light receiving state, so no ranging signal is obtained from the photoelectric conversion element array 15. . When the light beam passes through the optical path _l2 , the reflected light beam reflected by the subject 9 passes through the optical path _l2 ' and enters the photoelectric conversion element 15b, which is in the light receiving state, and the photoelectric conversion element array A ranging signal is obtained at 15. Then, when the light beam passes through the optical paths l ₃ and l ₄ , the reflected light beam reflected by the subject 9 is transferred to the photoelectric conversion elements 15 c and 15 d which are in the light receiving state again.
Therefore, the photoelectric conversion element array 15 cannot obtain a distance measurement signal. Therefore, the photoelectric conversion element from which the distance measurement signal was obtained is the photoelectric conversion element 15b.
Therefore, it can be seen that the subject 9 is at a distance D from the point _P2 . The above distance D is the base line length from the main optical axis O of the photographic lens 4 to the optical path changing mirror 11.
L ₁ and the base line length up to the light receiving lens 14 is L ₂ , then D=L ₁ tan θ ₂ or D=L ₂ tan ₂ .

In the above description of the operation, it is assumed that the object 9 is at a distance D from point _P2 and a distance measurement signal is obtained from the second photoelectric conversion element 15b, but in general, a distance measurement signal is obtained from the i-th photoelectric conversion element. If obtained, the distance D
is obtained from D=L ₁ tan θi or D=L ₂ tan i.

FIG. 3 shows another embodiment of the invention.
The distance measuring device of this example is different from the device of the embodiment shown in FIG. On the other hand, measurement can be carried out by using a light emitting element array 16 formed by arranging a plurality of light emitting elements 16a to 16d as a light source device and sequentially selectively changing the light emitting elements 16a to 16d to be lit. The irradiation direction of the distance beam is changed. That is, a lens 17 for condensing and projecting light is disposed correspondingly to the light projection window 5 of the camera body 2, and a light emitting element array 16 is disposed behind the lens 17. . The light emitting element array 16 is arranged such that the light emitting element 16a is located at a position corresponding to the optical path _l1 where the illumination angle θ is large, and the light emitting element 16d is located at a position corresponding to the optical path _l4 where the illumination angle θ is small. . In other words, the light emitting element 16a is located at the center of the camera body 2,
The light emitting element 16d is arranged so as to line the side of the camera body 2. Light emitting elements 16a to 16d
When one of the photoelectric conversion elements 15a of the photoelectric conversion element array 15 is driven to emit light, the corresponding photoelectric conversion element 15a of the photoelectric conversion element array 15
~15d are arranged to be in a light-receiving state alternatively.

It goes without saying that the distance measuring device configured in this way can also provide the same functions and effects as the distance measuring device shown in FIG. 2 above.

As described above, according to the present invention, the light receiving direction of the light receiving device is changed at the same time as the irradiation direction of the distance measuring light beam is changed, so that the photographic optical system and the distance measuring optical system are It is possible to provide a camera distance measuring device that is extremely convenient to use and does not cause parallax.

[Brief explanation of the drawing]

FIG. 1 is a front view of a camera equipped with the distance measuring device of the present invention, and FIG. 2 shows an embodiment of the present invention.
FIG. 3 is a schematic diagram of a camera distance measuring device showing another embodiment of the present invention. 4... Photographing lens, 5... Light emitting window, 6... Light receiving window, 9... Subject, 11... Optical path changing mirror (irradiation direction changing means), 12... Light emitting element (light source device), 15... ...Photoelectric conversion element array (light receiving device),
15a to 15d...Photoelectric conversion element, 16...Light emitting element array (light source device, irradiation direction conversion means).

Claims (1)

[Scope of Claim for Utility Model Registration] A light emitting window and a light receiving window provided at positions almost symmetrical to the photographic lens, a light source device that generates a beam of light for distance measurement, and the above-mentioned beam of light emitted from this light source device irradiation direction converting means for irradiating light toward a subject through the light projecting window and scanning the subject; and a plurality of photoelectric conversion elements arranged in a row for receiving the light beam reflected by the subject through the light receiving window. a light-receiving device comprising: a light-receiving device; and a light-receiving direction switching means for sequentially and selectively bringing each photoelectric conversion element of the light-receiving device into a light-receiving state depending on the irradiation direction of the light beam by the irradiation direction converting means. A camera distance measuring device characterized by: