JPH01287412A - Distance measuring instrument - Google Patents

Abstract

PURPOSE:To accurately position a light emitting element with simple structure by equipping a light emitting means with a base plate, the light emitting element, and means for moving and positioning the element, and providing movement guidance means on the fitting reference surface of the base plate and on the light emitting element. CONSTITUTION:The light emitting means shown in a figure is equipped with the base plate 11 which is supported on a camera body and supports a condenser lens 2, the light emitting element 14 mounted on the fitting reference surface 11b of the base plate 11, and means 14d, 13c, 13, and 17 to 19 for moving and positioning the element 14 on the base plate, and the movement guidance means 14a, 14b, 11a, 11c, 14e, and 14f which cooperate so as to move away from and to the surface 11b only in the direction of the base line length (X) between the light emitting means and a light receiving means are provided on the surface 11b of the base plate 11 and to the element 14. Consequently, the positioning accuracy of the element 14 in the optical axis (x axis) direction and up-down (y axis) direction of the light emitting means is determined by the formation accuracy of the base plate 11 and element 14, which is easily possible. The positioning may be only in the Z direction. The positioning of the element on the base plate is facilitated and the mechanism is simplified.

Description

Detailed Description of the Invention [Field of Industrial Application] The present invention relates to a distance measuring device suitable for small cameras such as lens/shutter cameras. means are provided at a predetermined interval, and when the light beam emitted from the light emitting means hits a subject and the reflected light from the subject enters a light receiving element of the light receiving means, the incident position of the light flux on the light receiving element is detected. In particular, the present invention relates to a triangular distance measuring device that measures the distance to a subject.

[Prior Art] FIG. 5 shows the measurement principle of a triangular distance measuring device. In the figure, 100 is a light emitting element, and 101 is a light emitting element 100.
111 is a light-receiving element; 112 is a light-receiving lens that forms an image of the reflected light from the subject S on the light-receiving element 111;

As shown in FIG. 5, the light beam emitted from the light emitting element 111 passes through the condenser lens 101 and is directed to a subject S at a predetermined distance A (or B) in an area O having a width Oz and a height Oy. (Po indicates the center of area 0.) and,
The diffusely reflected light passes through the light receiving lens 112 and passes through the light receiving element 1.
11.

The amount of displacement Az of the light receiving position PA from the predetermined position P on the light receiving element 111 has the following relationship.

Az=L・−・・・・・・・・・・・・・ ■However, L:
Base line length f: Focal length of light receiving lens 112 LA: Distance to subject S Here, as shown in FIG.
The axial direction and the vertical direction are defined as the y-axis direction, and the directions perpendicular to the above-mentioned X-axis and y-axis and in which the condensing lens 101 and the light-receiving lens 112 are lined up, that is, the base line length direction, are defined as the biaxial directions. In order to accurately measure distance using such a device, the following three conditions must be satisfied.

conditions! , At a predetermined distance HA, with respect to the z-axis direction,
The irradiated light beam of the light emitting element 100 and the light beam connecting the light receiving position PA on the light receiving element 111 and the center of the light receiving lens 112 coincide at the center Po of the area O.

Condition 2. Regarding the y-axis direction, the predetermined position of the light receiving element 111 and the center of the light receiving lens 112 should match, and the center of the light emitting element 100 and the center of the condensing lens 101 should match.

Condition 3. Regarding the x direction, the image of the light emitting element 100 at distance A has an appropriate size and is in focus.

Here, if condition! If this is not satisfied, as is clear from equation 0, the distance information will be obtained with an overall deviation, and correct distance measurement will not be possible.

If condition 2 is not satisfied, the image emitted from the light emitting element 100 and formed on the light receiving element 111 may protrude from the surface of the light receiving element 12.
As a result, the amount of light entering the light receiving element 11l decreases, and the S/N ratio of the electrical output from the light receiving element 11l deteriorates, causing erroneous distance measurement.

If condition 3 is not satisfied, the image of the light emitting element 100 will become too large on the surface of the light receiving element 111, causing the same problem as in the case of condition 2, or if it is not in focus, the image of the light emitting element 100 will become too large on the surface of the light receiving element 111. Since the brightness distribution of the image of the light emitting element 100 on the plane 111 changes, the displacement amount Az in FIG. 5 changes, which causes erroneous distance measurement.

Therefore, conventionally, in order to satisfy the above three conditions, a mechanism for adjusting the position of the light emitting element in the y-, y-, and z-axis directions is provided. An example thereof will be explained below based on FIGS. 6 to 8.

FIG. 6 shows a longitudinal section of the light emitting means, and FIG. 7 shows its plane.

The light emitting element l has a lens 1a in the front part from which the light beam is emitted.
are integrated into a package.

The light emitting element 1 is installed in the holder 2, and is elastically pressed against the holder 2 in the upper left direction in FIG. 6 by a leaf spring 5 whose one end 5a is fixed to the holder 2. Further, a spherical tip 6a of a vertical adjustment screw 6 screwed into the holder 2 from above is in contact with the light emitting element l.

This screw 6 resists the biasing force of the leaf spring 5 and presses the light emitting element 1 downward. Further, the position of the light emitting element 1 is restricted by the holder 2 in the direction perpendicular to the plane of the paper in FIG. Therefore, when the adjusting screw 6 is rotated, the light emitting element 1 is adjusted upwardly and downwardly with respect to the holder 2.

The holder 2 is housed within the ranging housing 3.

A pair of guide grooves 3a parallel to each other in the X-axis (optical axis) direction are formed on the upper and lower sides of the inner surface of the distance-measuring housing 3. Further, a pair of hemispherical protrusions 2b are formed on the upper and lower sides of the outer surface of the holder 2, and the hemispherical protrusions 2b fit into the guide grooves 3a, respectively. This allows the hemispherical protrusion 2b of the holder 2 to slide along the guide groove 3a, that is, in the X-axis direction. Further, the leg portion 7a of the first eccentric shaft 7 is rotatably press-fitted into the holder 2. The head 7b is slidably fitted into a long groove 3c formed in the upper part of the distance measuring housing 3. The long groove 3C is formed so that its long sleeve is orthogonal to the guide groove 3a, that is, parallel to z11l. Further, the leg portion 8a of the second eccentric shaft 8 is rotatably press-fitted into the holder 2. The head 8b is slidably fitted into another long groove 3d formed in the upper part of the distance measuring housing 3. The long groove 3d is formed so that the long groove is substantially parallel to the guide groove 3a. Further, a condenser lens 4 is attached to the front end of the distance measuring housing 3. Note that a light receiving element and a light receiving lens are also installed inside the ranging housing 3, but detailed explanation thereof will be omitted.

Next, the adjustment procedure will be explained.

First, in order to meet Condition 3 above, that is, to optimize the size of the light emitting element image, when the second eccentric shaft 8 is rotated, the leg 7a is displaced with respect to the head 7b, so that the leg 7a is connected to the leg 7a. The holder 2 is guided by the hemispherical protrusion 2b, the guide groove 3a, the eccentric shaft 8, and the long groove 3d, and is displaced in the X-axis direction. This movement changes the relative position of the condenser lens 4 and the light emitting element 1, and the beam width of the projected light is adjusted.

Next, in order to satisfy condition 2, the vertical adjustment screw 6
Rotate. Due to this rotation, the spherical tip 6a of the vertical adjustment screw 6 is displaced in the vertical direction in FIG. 6 with respect to the holder 2. When the spherical tip 6a moves upward, the light emitting element 1 is driven by the urging force of the plate spring 5, and when the tip 6a moves downward, the light emitting element 1 also moves downward against the urging force of the plate spring 5. In this way, the light emitting element 1 also moves in the vertical direction and is displaced with respect to the optical axis of the condenser lens 4. This relative displacement between the condenser lens 4 and the light emitting element allows the image of the light emitting element on the subject to be aligned with the optical axis of the light receiving section in the vertical direction, that is, in the y-axis direction.

Finally, the second eccentric shaft 8 is rotated to satisfy condition l. At this time, the leg portion 8a is displaced with respect to the head portion 8b of the second eccentric shaft 8, so that the holder 2 connected to the leg portion 8a rotates around the hemispherical protrusion 2b. Accordingly, the light projection direction moves in the z-axis direction. By this movement, the line connecting the point PA on the light receiving element and the center of the light receiving lens 112 can be made to coincide with the point Po in the predetermined MA on the optical axis of the light emitting means.

By the way, since the z-axis direction requires highly accurate adjustment,
Furthermore, a fine adjustment mechanism as shown in FIG. 8 is used.

Adjustment by the fine adjustment mechanism is performed by rotating the base length adjusting plates 1 and 3, which are rotatably supported between the light receiving lens 112 and the light receiving element 111 around the y-axis. At this time, the relationship between the rotation angle θ of the base line length adjustment plate 113 and the amount of movement Δ2 of the light emitting element lOO on the surface of the light receiving element 21 is as shown in the following equation.

・・・・・・・・・・・・ ■ However, d: Thickness of the base length adjustment plate n: Refractive index of the base length adjustment plate Here, d=0.8mtn, n=1.4836, θ=
If it is 1°, then a resolution of Δz=4.6 μm will be obtained.

In the conventional example described above, in addition to adjustment in the x, y, and z axis directions, a separate fine adjustment mechanism is used for the z axis direction, so the adjustment process takes time and requires a large number of parts. There were drawbacks such as high cost.

By the way, in order to make a compact camera such as a lens/shutter camera, etc., smaller, it is necessary to reduce the base line length in equation (2) and the focal point Mf of the light receiving lens.

Here, if the baseline length and focal length f are made smaller, the displacement of the image on the light receiving element surface at the same shooting distance fi A z
Therefore, in order to satisfy the above-mentioned conditions 1 to 3, it is necessary to further strictly control the positional accuracy of each component.

[Problems to be Solved by the Invention] Therefore, the technical problem to be solved by the present invention is to provide a triangular ranging type distance measuring device that has a simple structure and can accurately position a light emitting element. .

[Means, Actions, and Effects for Solving the Problems] In order to solve the above technical problems, the distance measuring device according to the present invention is configured as follows.

That is, in the present invention, the light emitting means includes a base plate supported by the camera body while supporting the condensing lens, a light emitting element mounted on the mounting reference surface of the base plate, and a light emitting element mounted on the base plate. means for moving and positioning with respect to the plate, and further, the mounting reference surface of the base plate and the light emitting element are such that the light emitting element is moved only in the base line length direction between the light emitting means and the light receiving means with respect to the mounting reference surface. They are characterized in that they each have movement guide means that cooperate to move.

In the above configuration, the positioning accuracy of the light emitting element with respect to the optical axis direction, that is, the X-axis direction, and the vertical direction, that is, the X-axis direction, of the light emitting means is determined by the plastic molding accuracy of the base plate and the light emitting element, but this accuracy is relatively easily achieved. The light emitting element may be positioned in the base line length direction, that is, in two axial directions. Therefore, the positioning of the light emitting element with respect to the base plate is extremely simplified compared to the conventional example, and the adjustment mechanism and its operation for this purpose are both simple.

[Example] Examples of the present invention will be described in detail below with reference to FIGS. 1 to 4.

FIG. 1 is a plan view of a light emitting means or a light emitting part of a distance measuring device of a camera, FIG. 2 is a cross-sectional view taken along the line 1--2 in FIG. 1, and FIG. 3 is an exploded perspective view of a main part of the light emitting means.

In the figure, reference numeral 11 denotes a base plate, which is supported by a camera body (not shown). The base plate 11 supports the entire optical system including a light emitting system and a light receiving system (not shown). As shown in the figure, in the light emitting system, the condenser lens 12 is supported on the front part of the base plate 11, and the rear part, that is, the mounting reference surface 1
A packaged light emitting element 14 is supported on 1b1.

The light emitting element 14 includes three guide pins 14a, 14a, and 14b on its front reference surface 14c. Two of the pins 14a, 14a are placed on the left and right sides of the top, and the other pin 14b is placed at the center of the bottom.

On the other hand, the reference surface 11b of the base plate 11 has a guide groove 1 into which the pair of upper pins 14a, 14a of the light emitting element 14 fit.
1a and a guide groove 11c into which the lower pin 14b fits, so that the light emitting element 14 can move only in the Z-axis direction with respect to the base plate 11, that is, in the baseline length direction between the light emitting means and the light receiving means. It has become.

A holding frame 15 is fixed to the rear part of the base plate 11.

This holding frame 15 holds two leaf springs 17,18. As clearly shown in FIG. 2, one leaf spring 17 is brought into contact with the back surface of the light emitting element 14, thereby elastically moving the reference surface 14c of the light emitting element 14 onto the base plate 11.
is pressed against the reference surface itb. Now one leaf spring 18
is brought into contact with one side of the light emitting element 14, thereby constantly urging the light emitting element 14 upward in FIG. 1, that is, in the direction toward the light receiving system (not shown) (Z-axis direction). ing.

In the figure, reference numeral 13 denotes an adjustment plate, which is attached to the upper surface of the base plate 1 so as to be slidable in the X-axis direction. Adjustment plate 1
A guide groove 13a is formed in the front portion of the base plate 3, and a headed guide pin 10 fixed to the upper surface of the base plate 11 is inserted into the guide groove 13a.

Further, a raised piece 13d and a guide groove 13b are formed in the rear portion of the adjustment plate 13. A guide protrusion 15a formed on the holding frame 15 passes through the guide groove 13b. The adjustment plate 13 has these guide pins IO and guide protrusions 1
Movement in the X-axis direction is guided by 5a.

The adjustment plate 13 is always urged rearward in the X-axis direction by a spring 19 interposed between the adjustment plate and the holding frame 15. On the other hand, an adjustment screw 16 is screwed into a predetermined portion of the adjustment plate 13, and its tip abuts against the cut-out piece 13d of the adjustment plate 13 from the back side. That is, by adjusting the adjusting screw 16, the adjusting plate 13 can be moved forward against the spring force of the spring 19.

The adjustment plate 13 has an adjustment pin 13c fixed to a predetermined portion thereof.
have. This pin is the cam surface 14d of the light emitting element 13.
We are now collaborating with That is, when the adjustment plate 13 is pushed forward, the adjustment pin 13c acts on the cam surface 13d, causing the light emitting element 14 to move downward in the Z-axis direction in FIG. On the other hand, when the adjustment plate 13 is moved backward, the light emitting element 14 is moved in the opposite direction by the biasing force of the leaf spring 18.

The amount of movement Δ2 of the light emitting element 14 in the base length direction is expressed by the following formula (%). However, P: Pitch θ of the adjustment screw 16: Rotation angle ψ of the adjustment screw 16: Inclination angle of the cam surface 14d with respect to the X axis Here, for example, If P=0.35 am and ψ=23°, Δz=0.41 μm/deg, and a sensitivity approximately lθ times that of the conventional fine adjustment mechanism can be obtained.

According to the above configuration, by molding the outer shapes of the base plate 11 and the light emitting element 14 with high precision by plastic molding, the base plate 11 ? It is possible to perform two-pair positioning with high precision, and position adjustment in the X-axis direction and the y-axis direction becomes unnecessary.

Further, the position of the light emitting element 14 in the base line length direction, that is, the Z-axis direction can also be adjusted with extremely high precision.

4A to 40 show modified examples of the package of the light emitting element 14, respectively.

In FIG. 4A, a protrusion 14a° in which the pair of guide pins 14a, 14a in FIG. 3 are connected, and a protrusion 14b' corresponding to the guide pin 14b in FIG.
is formed. If the package of the light emitting element has a protrusion having such a shape, it is natural that the base plate 11
The reference plane itb includes those protrusions 14a' and 14b'.
A guide groove is formed into which the guide groove is to be fitted.

In FIG. 4B, guide grooves 14e and 14f are formed above and below the reference surface 14c of the light emitting element.

In this case, a protrusion or protrusion that fits into these guide grooves 14e and 14r is formed on the reference surface ttb of the base plate 11.

FIG. 4C shows an example in which the cam surface 14d is not formed on the light emitting element 14. In this case, the position of the light emitting element 14 in two axial directions is adjusted using an appropriate tool.

[Brief explanation of the drawing]

1 to 4 show embodiments of the present invention, FIG. 1 is a plan view of the light emitting means of the distance measuring device of the camera, and FIG. 2 is the one shown in FIG.
A line-bending sectional view, Figure 3 is an exploded perspective view of the main parts of Figures 1 and 2,
Figures 4A, 4B, and 40 are perspective views showing modified examples of the light emitting element, Figure 5 is an explanatory diagram showing the principle of triangulation, and Figure 6
, 7 are a sectional view and a plan view of a light emitting means of a distance measuring device according to a conventional example, and FIG. 8 is an explanatory diagram showing a fine adjustment mechanism in the Z-axis direction according to the same conventional example. 10... Guide pin, 11... Base plate, 11a, 11
c...Guide groove, ttb...Reference surface, 12...Condenser lens, 13...Adjustment plate, 13a, 13b...Guide groove, 13c...Adjustment pin, 13d...Cut Raising piece, 14... Light emitting element, 14a, 14b... Guide pin, 14c... Reference surface, 14d... Cam surface, 14
e, 14f... Guide groove, 15... Holding frame, 15a
... Guide protrusion, 16 ... Adjustment screw, 17 ... Plate spring, 18 ... Plate spring, I9 ... Spring. Patent applicant: Minolta Camera Co., Ltd. Representative: Patent attorney: 1 person: Figure 7 Figure 8

Claims (1)

[Claims] 1. Light emitting means for emitting a luminous flux toward a subject;
In a triangular distance measuring device comprising a light receiving means for receiving reflected light from a subject, the light emitting means is supported by a camera body and a base plate supporting a condensing lens (2). (11) and the base plate (11)
The light emitting element (
14), and means (14d; 13c, 13) for moving and positioning the light emitting element (14) with respect to the base plate (11).
;17:18:19), and further includes the base plate (1
1) The mounting reference surface (11b) and the light emitting element (14) are
Movement guide means (14a, 14b; 11a, 11c) that cooperate so that the light emitting element (14) moves only in the baseline length direction between the light emitting means and the light receiving means with respect to the mounting reference surface (11b).
: 14a', 14b', 14e, 14f).