JPH07306358A - Range finder of camera - Google Patents

Abstract

PURPOSE:To provide a range finder of camera which has a simple constitution and can find the ranges to many object points within a picture with high accuracy and at a high speed. CONSTITUTION:This range finder has a light projecting element 1 projecting plural luminous fluxes to an object, a turning mirror 8 performing scanning with the luminous flux emitted from the light projecting element 1 in a specified area within the picture, a pair of light receiving lenses 3a, 3b and PSDs 4a and 4b respectively receiving reflected light from the object made by projected light with which scanning is performed, photoelectric conversion light receiving circuits 5a and 5b, and a CPU10 where a distance calculating means respectively calculating distance to the object responding to the output of the light receiving circuits 5a and 5b is incorporated.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a distance measuring device for a camera, and more particularly to a distance measuring device for a camera which projects distance measuring light onto a plurality of points of an object and determines the object distance from the reflected signal light. Regarding

[0002]

2. Description of the Related Art Conventionally, as a proposal relating to a distance measuring technique in which a plurality of distance measuring points are two-dimensionally arranged in a photographic screen so as to eliminate points that cannot be measured, Japanese Patent Laid-Open No. 284019/1990 has been proposed. The distance measuring device disclosed in
It is a device that adjusts light in a first direction and a second direction by a prism, projects the light on a plurality of points on a subject, and measures the distances between corresponding points on the subject by the reflected light.

Further, the distance measuring device for a camera disclosed in Japanese Patent Laid-Open No. 4-212136 is a device capable of rotating a distance measuring unit to measure a plurality of points on a screen.

[0004]

However, the distance measuring device disclosed in the above-mentioned Japanese Patent Laid-Open No. 2-284019 does not have a sufficient description of the configuration on the light receiving side, and it is unclear how the distance is measured. There were many. Further, Japanese Patent Laid-Open No. 4-212113
In No. 6, since the entire distance measuring unit is rotated in order to increase the number of distance measuring points, there is a problem that the device becomes large and energy and a long time are required for the above rotation. It was Further, it is difficult to arrange the distance measuring points two-dimensionally on the screen.

In view of the above points, the present invention provides a distance measuring device for a camera having a simple structure and capable of measuring many object points in a screen with high accuracy and high speed.
One purpose. Another object of the present invention is to provide a distance measuring device for a camera that can obtain appropriate distance data according to a shooting state and can perform focusing.

[0006]

According to one embodiment of the distance measuring apparatus for a camera of the present invention, a light source means for projecting a plurality of light beams toward an object, and a light beam emitted from the light source means in a predetermined screen. Projection light scanning means for scanning in the area, and light reflected from the subject by the projected light scanned respectively,
It has a pair of light receiving means for photoelectric conversion, and a distance calculating means for calculating the distance to the subject in response to the output of the light receiving means. In this device, the distances to the plurality of subject points are calculated in response to the output of the light receiving means.

Another camera distance measuring device of the present invention is
Light source means for projecting a plurality of light beams toward the subject, projection light scanning means for scanning the light emitted from the light source means in a predetermined area in the screen, and reflected light from the subject by the scanned projection light, respectively. A pair of light receiving means for receiving light and photoelectrically converting it, a distance calculating means for calculating the distance to the object in response to the output of the light receiving means, and a plurality of distance data from the distance calculating means are inputted. And selecting means for selecting only one piece of distance data from the photographing optical system, and the focusing optical system is focused on the distance measuring point corresponding to the distance data selected by the selecting means.

[0008]

Embodiments of the present invention will be described below with reference to the drawings. 1 is a main block diagram of the light emitting / receiving unit of FIG. 1, showing an outline of a distance measuring device for a camera according to a first embodiment of the present invention.
This will be described with reference to the main block configuration diagram of the light projecting unit and the control unit in FIG.

As shown in FIG. 1, the distance measuring device of the camera has a light source means for projecting a plurality of light fluxes toward a subject and a projection light scanning means for scanning the light fluxes from the light source means in a predetermined area on the screen. And a light receiving unit 102 which is a pair of light receiving means for receiving and photoelectrically converting reflected light of a plurality of light beams from a subject, and a control for controlling light emission and scanning of the light projecting unit 101. Means for incorporating the above-mentioned light receiving portion 10
The distance calculating means 10a for calculating the distance data of a plurality of distance measuring points of the subject based on the output from 2 is incorporated, and appropriate from the distance data based on the focal length information of the photographing optical system and the posture information of the camera. Incorporating a selection unit 10b for selecting one of the distance data, focusing control is performed via the focusing drive system 103 to a distance measurement point corresponding to the distance data of the photographing optical system 104, and control of the entire camera. It is mainly configured by a control unit 100 that has a built-in camera control means for performing.

The light projecting section 101 is mainly composed of a light projecting lens 7
A plurality of light source means, in this case, three light emitting elements IRED1a, 1b, 1c, which are independent infrared light emitting diodes, and to project light from the light emitting element 1 in different directions sequentially. And a rotatable mirror 8 which is a projection light scanning means. The projection light scanning direction and the projection arrangement direction of the plurality of light emitting elements are substantially orthogonal to each other.

The light receiving section 102 is mainly composed of a pair of light receiving lenses 3a and 3b and light position detecting elements (PSD) 4a and 4b.
And light receiving circuits 5a and 5b configured by AFIC or the like. This pair of light receiving lenses 3a, 3b
In this embodiment, the PSDs 4a and 4b are the light projecting section 10 described above.
Although it is assumed to be disposed at a vertical position with respect to 1, which is orthogonal to the scanning direction, the disposed position may be at the left or right or at an inclined position.

The control unit 100 has the distance calculating means 1
0a, the selection means 10b, and a CPU 10 which is an arithmetic control circuit including a one-chip microcomputer or the like which incorporates camera control means such as focus drive control.

In the distance measuring device having the above-mentioned main structure, the rotation mirror 8 is controlled by the CPU 10 from the light projecting portion 101, and the light projected in different directions is reflected by the object and is received by the above-mentioned light receiving device. The light enters the portion 102, and the incident position is detected by the PSDs 4a and 4b. Light receiving circuits 5a, 5
The incident position of the reflected light of the subject is obtained based on the detection output of b, and selected from a plurality of distance measuring points of the subject described later on the basis of the principle of light projection type triangulation having a pair of light receiving units described later. The distance data of the distance measuring point is the CPU
The distance is calculated by the distance calculating means 10a in 10.

Furthermore, from the distance data, the selection means 10b in the CPU 10 selects only one distance data which is more appropriate on the photographing screen than the focal length information of the photographing lens which is the photographing optical system and the photographing posture information of the camera. And the photographing optical system 10 to a position where the point corresponding to the distance data is focused.
4 is driven.

Next, regarding the principle and merits of distance measurement in AF (autofocusing) processing by the light projection type triangulation method using the pair of light receiving portions, an optical path diagram of the pair of light receiving portions 102 in FIG. Will be explained.

First, the reflected light of the projected spot 15 projected on the center of the screen is received by the light receiving lenses 3a and 3a of the light receiving section 102.
2, the light incident positions x1 and x2 given by the distances from the reference points on the PSDs 4a and 4b as shown in FIG.
On the points S (x1) and S (x2). The positional relationship between the pair of PSDs 4a and 4b must be such that the optical position detection directions of the elements face each other.

Considering the distance S between the principal points of both light receiving lenses 3a and 3b as the distance S1 + S2 as shown in FIG. 2, the focal length fJ of both light receiving lenses and the object distance L are L = S1.fJ / x1 = It is represented as S2.fJ/x2 (1). Then, S = S1 + S2 = x1.L / fJ + x2.L / fJ = (L.1 / fJ). (X1 + x2) ... (2) Therefore, L = S.fJ / (x1 + x2) ... (3) Becomes Therefore, the light incident positions x1 x of the PSDs 4a, 4b
If 2 is obtained, the subject distance L can be obtained.

The PSDs 4a and 4b are semiconductor elements having a photovoltaic effect and a carrier dividing effect that output two current signals depending on the light incident position, and the light receiving circuits 5a and 5b are the semiconductor elements. Input the output current, calculate, and calculate the signals proportional to the light incident positions x1 and x2, respectively.
An integrated circuit for outputting to PU10, which is AFIC
Is called.

Now, in the light receiving section having such a structure, when the light spot 15 is displaced by the displacement ΔX on the subject and projected onto the point of the light spot 16 as shown in FIG. The light incident positions of are
The amount of shift Δx1 Δx2 is shifted. At this time, (3)
When x1 + x2 of the denominator of the formula is calculated, x1 + x2 = x1 + Δx1 + x2 -Δx2, and if the optical system is symmetric, Δx1 = Δx2. Therefore, Δx1 -Δx2 = 0. It can be seen that the subject distance L can be determined by.

With the above-mentioned structure, even if the distance measuring light is projected onto various points in the direction of ΔX in the photographic screen, the object distance L can be obtained by simply obtaining x1 and x2. Means that can be determined.

Next, regarding the position of the projected spot, the position Δ
Considering the influence when the spot position is changed to the position ΔY in the direction orthogonal to X, as shown in the perspective view of the light receiving state of FIG. 3, the spot 17 deviated from the light spot 15 by the light point ΔY is also included. Similarly, on the PSDs 4a and 4b,
In the x direction, the points S at the incident positions x1 and x2
It can be seen that the signal light is incident on the position equivalent to (x1) and S (x2). That is, in the present distance measuring apparatus, even if the light incident positions x1 and x2 up to the incident light position are obtained even with respect to the change of the position ΔY of the light projection spot, the correct object distance L according to the above formula (3) Can be calculated.

As described above, in the light projection type triangulation using the pair of light receiving portions, the position of the light projection spot is set in the X direction or
Even if the light spot position is changed in the Y direction, it is possible to easily obtain the distance data of the light spot position. For example, as shown in the shooting screen of FIG. 4, even in a scene in which the main subject 13 does not exist in the central portion 12 of the screen 11, the light projecting unit 101 can be used.
By operating the rotating mirror 8, the light projection spot position is shifted to the point 12a where the main subject exists, distance measurement is performed at that point, and distance data can be easily obtained. Then, it becomes possible to focus on the main subject 12.

Based on the above-described structure, the distance measuring device for the camera of this embodiment will be described in more detail. Figure 5
FIG. 3 is a block configuration diagram of a light projecting unit and a CPU. In the light projecting unit 101, the light projecting element 1 which is a light source means is an infrared light emitting diode IR capable of independently projecting light as described above.
ED 1a, 1b, 1c, each selectable driver 6
It is possible to project light in a time-sharing manner via.

The light projecting lens 7 is composed of the above-mentioned IRED1s.
The light beams a, 1b, and 1c are condensed and projected onto a subject through a rotary mirror 8 that is a projection light scanning unit. The rotating mirror 8 can be rotated by a motor 9a, which is a projection light scanning unit driven by the CPU 10 and a motor driver 9b, and the light emitting point is scanned by this rotation. The scanning direction is as shown in FIG.
The longitudinal direction of the photographing screen 11, ie, the direction along the X direction (see FIG. 4). In addition, the above IRED1a, 1b, 1
The arrangement direction of c is substantially parallel to the rotation axis direction of the rotation mirror 8.

However, the relationship between the scanning direction of the light projecting portion 101 and the projection row direction of the plurality of light emitting elements with respect to the longitudinal direction of the photographing screen in FIG. 4 is not necessarily limited to that of this embodiment.

The CPU 10 is a photographing optical system 104 of the camera.
The focal length (f) information of the taking lens barrel is taken in through, for example, the f input unit 30 which is an encoder or the like attached to the lens frame of the zoom lens. Up, longitudinal direction (X direction)
Is taken in through a posture detecting unit 31 which will be described later.

Then, a required distance measuring point is selected from a plurality of distance measuring points according to the photographing state based on the focal length (f) information and the camera attitude information, and further, the required distance measuring point is selected. The distance data is calculated by the distance calculation means 10a, and one distance data suitable for the photographing condition is selected by the selection means 10a. As the camera, the focusing optical system 104 is driven to drive the distance measurement point corresponding to the distance data.

FIG. 6 shows an example of a mercury switch 31A applied as the camera attitude detecting section 31. Liquid mercury 131 is contained in the glass ball tube 135 and moves in the ball tube according to the attitude of the camera. The glass ball tube 135 is provided with two electrodes 132 and 134. If the electrodes 132 and 134 are in the conducting state, it is determined that the camera posture is vertical. If the electrodes 132 and 134 are not conducting, the camera posture is It is determined to be horizontal.

FIG. 7 is a time chart of the change of the mirror scan (rotation) angle in the light projecting section and the light emission timing of each IRED. As shown in this figure, the turning mirror 8
When the IREDs 1a, 1b, and 1c are sequentially emitted while scanning, and the light is projected toward the subject, as shown in the ranging point display screen 11A of FIG.
The light flux for distance measurement is distributed at the distance measurement points P (1a) to P (3b) to P (5c) corresponding to a, 1b, 1c and the light emission timings t1 to t5.

In practice, since the timings of light projections of the respective IREDs are slightly deviated, strictly speaking, distance measuring points at the same timing tn, for example, P (1a), P (1b), P (1c)
Does not lie on a straight line that is completely parallel to the Y direction, but the distance measuring points can be arranged as shown in FIG. 8 depending on the scanning speed and the distance measuring timing.

However, if the above 15 distance measuring points are constantly measured, the time lag due to the distance measurement becomes long. Therefore, in the present embodiment, the f input unit 30 (see FIG. 5) for inputting the focal length information (f) corresponding to the zoom position of the photographing lens of the camera, and the posture when the camera is held are displayed on the photographing screen of the camera. The output of the vertical / horizontal detection unit 31 (see FIG. 5) for detecting whether the vertical / horizontal direction (longitudinal / short-side direction) faces the horizontal direction or the vertical direction is input to the CPU 10 and the photographing conditions at that time are input. Select the required distance measurement point accordingly. The distance calculation is performed only for the necessary distance measurement points, and the time lag due to the calculation during distance measurement is reduced.

The operation of selecting the distance measuring points for each specific photographing condition will be described. For example, referring to FIG.
In the vertical composition of the photographing screen 51 when the camera is in the vertical attitude as shown in (A), the person 13 with the tall building 14 in the background is assumed, and the downward projection is emphasized as the projection point.
Select the distance measuring point P (marked with a circle) in the lower part.

Further, as shown in FIG. 9B, the main posture of the camera is horizontal, and the main subject 13 is considered to be far away on the telephoto side shooting screen 52.
At this time, the photographer's eyes tend to gaze at the center of the screen, so the projection point P (marked with a circle) should be located in the center of the screen as much as possible.
To focus on a rough subject that the photographer is not aware of.
Distance is measured without hitting the projected spot.

In addition, as shown in FIG. 9C, in the horizontal composition in which the camera is in the horizontal orientation, and in the wide-angle shooting screen 53, a snap in front of the landscape is assumed, and the horizontal projection is as wide as possible. The light point P (marked with a circle) is taken, and the distance measurement pattern is taken into consideration at the bottom of the screen as in the vertical composition.

Next, the distance measuring operation of the distance measuring device for a camera of the present embodiment having the above-mentioned structure will be described with reference to the flowchart of FIG. First, step S1 is a step of detecting closing of a first release switch (1st switch) provided on a release button of a camera. When the switch is turned on, the CPU 10 determines that the photographer has started photographing, and starts the flow of distance measurement. A step S2 inputs the focal length in order to detect whether the taking lens of the camera is on the telephoto side or the wide-angle side based on the output signal of the f input unit 30 described above. Step S3 is a step of posture detection (vertical and horizontal composition detection) of the camera based on the output of the vertical / horizontal detection unit 31 described above.

When it is determined in step S3 that the vertical composition is determined, the process branches to step S20, and the CPU 10 rotates the motor 9a via the motor driver 9b to start scanning the rotating mirror 8. Then, step S21
When the turning mirror 8 is turned to the position where the distance measuring light is projected at the point of the timing t2 in the screen of FIG. 8, the steps S22 to S24 are executed.
The CPU 10 sequentially causes the IREDs 1a, 1b, 1c to emit light, and detects the position of the reflected signal light. And AFIC
The subject distances L2a, L2b, L2c are calculated from the outputs of the (light receiving circuits 5a, 5b) based on the equation (3).

Subsequently, in step S25, when it is detected that the turning mirror 8 reaches the timing of projecting the distance measuring light to the point of t3, the central IRED 1b is caused to emit light in step S26. , The CPU 10 detects which position of each PSD 4a, 4b the reflected signal light has entered by using the AFIC (light receiving circuits 5a, 5b),
The subject distance L3b is calculated based on the equation (3).

In this way, as shown in FIG. 9A, the distance measurement of one point at the center and the three points at the bottom of the screen is completed. Data is selected, and in step S27, this value is selected as the focusing distance LP.

On the other hand, if it is detected in step S3 that the attitude of the camera is horizontal, the process branches to step S4. Therefore, it is determined whether or not the zooming position selected by the user is 50 mm or more in the lens focal length f. If it is 50 mm or more, it is determined to be the telephoto side, and step S
Branch to 30. If it is less than 50 mm, the wide angle side
It branches to step S5.

First, in the case of branching to step S30, the distribution state of the distance measuring light is shown at a plurality of distance measuring points as shown in the photographing screen 52 of FIG. 9B. In step S30, C is set via the motor driver 9b.
The PU 10 rotates the motor 9a to start the scanning operation of the rotating mirror 8.

When it is detected in step S31 that the angle of the rotary mirror 8 has reached the position of the timing t2 on the screen 11 in FIG. 8, the central portion in the vertical direction of the screen is measured in step S32. The IRED 1b that is distant is caused to emit light, and at that time, the reflected signal light obtained from the subject is transmitted to the PSD 4a,
Light is received at 4b. The incident position is detected by using the AFIC (light receiving circuits 5a, 5b), and the CPU 10 calculates the subject distance L2b by using the equation (3).

Next, in step S33, the timing at which the rotary mirror 8 reaches the position where light can be projected at the position t3 on the screen of FIG. 8 (hereinafter, abbreviated as "timing at t3").
If it is determined that
At 36, the IREDs 1a, 1b, 1c emit light, and the distances L3a, L3b, L3c of the corresponding points are sequentially calculated.
Next, when the timing of t4 is determined in step S37, the IRED 1b is caused to emit light in step S38,
The subject distance L4b is calculated.

In this way, the distance measuring points in the screen 52 as shown in FIG. 9B are sequentially projected, and in step S39, the distance measuring points of these distance points are closest to each other. Focusing distance Lp for one distance data
To choose as.

Further, if the photographing lens focal length f is less than 50 mm in the determination of step S4 and the process branches to step S5 or less, it means that the image is in the horizontal composition and on the wide-angle side. The distance of the point is measured on such a shooting screen. That is, in step S5, the variable m indicating the number of horizontal coordinates of the distance measuring point and the flag a having the value 1 when the vertical distance measuring results are substantially equal are reset.

In step S6, the above m is incremented, and in step S7, when it is determined that m is not 6, that is, it is determined that the distance measurement at five points in the horizontal direction of the screen has not been completed. If step S8,
In step S9, the central portion in the vertical direction of the screen and the lower portion from the central portion are sequentially irradiated, and the distance data Lm of each distance measurement result
b and Lma are calculated.

Then, in step S10, it is determined whether or not the distance data Lma and Lmb are substantially equal, and if the results are substantially equal, the process branches to step S12 and the flag a is set to 1. Then, in step S13, the result of averaging the distance data Lmb and Lma is set as the distance data Lm. Then, scan a predetermined amount in step S11,
The procedure returns to step S6.

The reason for adopting the processing of steps S10 to S13 is that in the composition in which the camera is arranged horizontally and the zooming angle is wide, the point at which substantially equal distance data is output in the vertical direction is the person 13 in FIG. 9C. This is because the probability of being the main subject is high, and the priority is higher than that of the distance measuring point 12a that shows the result of the short distance in only one of the vertical direction of the screen. That is, when photographing a person, it is usually assumed that there are many compositions in which the face is brought to the central portion in the vertical direction. When the face is located in the center of the screen, it is considered that the body is always present under the face, and the main subject 13 is detected when the faces are vertically aligned and the distance measurement results are substantially the same.

In step S13, (Lma + L
The reason why mb) / 2 is set to Lm is that it is considered that averaging will increase reliability if distance measurement results of the same subject are obtained.

If it is determined in step S7 that m has become equal to 6 after completion of the distance measurement of 5 points in the horizontal direction, the process branches to step S14. In step S14, when it is confirmed that the flag a is 1 through the step of step S12, the process proceeds to step S15, and among Lm obtained in step S13, the one that is closer to the center of the screen instead of ∞ is selected. As a main subject, this distance is L
p.

On the other hand, when the vertical distance measurement results are not obtained at any point, the flag a is 0, so the process branches from step S14 to step S17. And
The closest distance data is selected from the distance measurement results L1b to L5b at the central portion in the vertical direction of the screen and designated as Lp. At this time, the reason why the lower data L1a to L5a are not used is to prevent the front shelf 12b or the like from being in focus in the composition as shown in FIG. 4, for example.

Next, in step S16, the Lp is focused, and the focusing sequence ends.
Although not shown in the figure, it goes without saying that an exposure sequence and a reset sequence of the rotating mirror 8 are subsequently performed.

As described above, according to this embodiment,
As shown in FIGS. 9 (A) to 9 (C), a main subject existing at various positions on the screen is found in consideration of shooting conditions, for example, the horizontal and vertical directions of the composition, the focal length of the lens, and the like. High-speed and high-accuracy camera AF for accurate focusing
It is possible to provide a distance measuring device for (autofocus processing) device.

It is shown in the time chart of FIG. 7 that only one scanning direction is the rotating direction of the rotating mirror that can increase the speed in the distance measuring process of the distance measuring device of this embodiment. As described above, the rotation stop operation of the rotary mirror 8 as a scanning member is not provided, and the distance measuring points are reduced according to the shooting conditions. On the other hand, the high accuracy is possible because the light receiving system of the light receiving unit 102 is paired and the configuration is adopted in which they are mutually corrected as described in FIG.

Next, a distance measuring device for a camera showing a second embodiment of the present invention will be described. The distance measuring apparatus according to the present embodiment is different from the distance measuring apparatus according to the first embodiment in the configuration of the light projecting unit. Since the configuration other than the light projecting unit is the same as that of the device of the first embodiment, detailed description thereof is omitted.

FIG. 11 shows the light projecting section 2 of the distance measuring apparatus of this embodiment.
It is a block diagram of 01. In the light projecting unit 201,
As a light emitting element of the light source means, a xenon discharge arc tube (Xe tube) used in a strobe device or the like is used so that a light amount many times that of the IRED of the device of the first embodiment shown in FIG. 5 can be used. . Therefore, it is possible to provide a distance measuring device for an AF device, which is capable of far higher accuracy and is capable of handling long distances.

The structure of the light projecting unit 201 will be described. As shown in FIG. 11, a Xe tube 29 as a light projecting element is used.
Is disposed behind the light projecting lens 7. The Xe tube 29
Mirrors 20a and 20b are obliquely provided above and below the Xe tube 29. Further, the Xe tube 29, the mirror 20a,
On the front surface of 20b, a mask 21 is disposed as a projection light scanning means that is supported so as to be movable along the Xe tube 29 axial direction.

The mask 21 is engaged with a feed screw 22 which is rotationally driven by a motor 23 as a projection light scanning means. Further, the mask 21 is provided with a plurality of, in this case, three opening holes 21a, 21b, and 21c at arrangement positions inclined with respect to the moving direction. And the mask 2
The position of 1 in the optical axis direction is the focal length fT of the light projecting lens 7.
The positions are separated from each other.

The opening holes 21a, 2 of the mask 21 are
1b and 21c are spaced apart from each other in the moving direction by the opening holes 21a and 21c.
The light emitted through b and 21c is simultaneously received by the light receiving unit 102.
The intervals are set so that the PSDs 4a and 4b do not enter the effective detection range. The reason why the distance between the apertures is limited in this way is that a plurality of light beams are simultaneously incident on the PSDs 4a and 4b and a detection error due to crosstalk does not occur.

The Xe tube 29 is caused to emit light by the CPU 10 through the light emitting circuit 25 including a booster circuit, a discharge charge charging capacitor and a trigger circuit. Along with this emission, the distance measuring light is directly emitted from the Xe tube 29 or the mirror 2
The light is reflected at 0a and 20c and is emitted forward as indicated by arrow directions Ba, Bb, and Bc. At this time, the CPU 10 rotates the motor 23 via the motor driver 24,
The mask 21 is driven in the arrow X direction by the feed screw 22. With the movement of the mask 21, the opening holes 21a,
The projection light transmitted through 21b and 21c is scanned in the X direction.

The light receiving section 102 applied to this embodiment.
Of the pair of light receiving lenses 3a and 3b and PSD 4a,
It is assumed that 4b are arranged to face each other in the up-down direction orthogonal to the X direction, which is the moving direction, with the light projecting unit 201 as the center. However, also in this example, the pair of light-receiving portions is not limited to the above-mentioned arrangement position and may be arranged on the left and right.

The light projecting operation of the light projecting unit 201 of the distance measuring apparatus of the present embodiment configured as described above will be described. First, the light beam Ba is projected through the opening hole 21a of the mask 21 at a predetermined timing and projected. It is projected onto the subject through the optical lens 7. Then, the light beam Bb is emitted from the opening 21 b of the mask 21.
However, the light beam B from the opening 21c of the mask 21 continues.
c is projected at a predetermined timing.

During this time, since the mask 21 is moving in the X direction, as shown in the optical path diagram of the light projecting portion of FIG.
And the opening hole 21a of the mask 21 or 21
The angle formed by the X-direction movement position xT of b and 21c changes. That is, the projection angle θ changes using the focal length fT of the lens 7 in the relationship of θ = arctan xT / fT (4).

X is synchronized with the change of the opening holes 21a to 21c.
When the e tube emits light, as shown in the photographing screen 55 of FIG. 13, the distance measuring light is sequentially projected to the respective distance measuring points P1 to P9 on the screen. In this case, the X direction, which is the moving direction of the mask 21, is made coincident with the longitudinal direction of the photographing screen.
Then, in synchronization with this light projection, the light receiving means 102 similar to that shown in FIG.
The subject distance at each point can be calculated at 10.

As described above, in the distance measuring apparatus of the present embodiment, only one Xe tube 29 needs to be used as the light projecting element, and if the mask 21 is simply moved by the motor 23 or the like, a plurality of luminous fluxes can be obtained. Can be scanned, thus simplifying the configuration. Further, since the Xe tube is applied to the light projecting portion, it is possible to expect an effect such as an increase in accuracy due to an increase in the amount of light and a long distance measurement.

Next, a distance measuring apparatus for a camera showing a third embodiment of the present invention will be described with reference to the block diagram of the light projecting section of FIG. 14 and the optical path diagram of the light receiving section of FIG. The distance measuring device of this embodiment is characterized in that the opening hole position of the mask 31 which is the projection light scanning means is different from that of the distance measuring device of the second embodiment as shown in FIG. Further, as the light receiving section, a pair of light receiving sections are arranged above and below the light projecting section. The other structure is the same as that of the device of the second embodiment.

In the light projecting section 301 of the apparatus of this embodiment, the opening hole 31a of the mask 31, which is the projection light scanning means,
The arrangement of 31b and 31c is the upper and lower opening holes 3 as shown in FIG.
1a and 31c are arranged at predetermined intervals at upper and lower positions substantially orthogonal to the X direction of the mask moving direction. The opening 3
The lights from 1a and 31c can be projected simultaneously. The opening hole 31b is arranged at a central position which is separated from the opening holes 31a and 31c by a predetermined amount in the moving direction. Light emitted from the opening hole 31b is projected onto a point on the center line of the screen.

The vertical distance between the opening holes 31a and 31c is
It is determined from the light projection angle together with the arrangement inclination angles of the mirrors 20a and 20b. The necessary vertical distance and the mirror inclination angle will be described. FIG. 15 is an optical path diagram of the light receiving portion of the present embodiment and shows an optical path diagram in a vertical cross section in the vertical direction. If the distance measuring lights simultaneously emitted from the Xe tube 29 of the light projecting unit 301 through the light projecting lens 7 are at relatively close positions such as the projecting points (spots) 150A and 160A, both distance measuring lights are measured. Distance light is received by both Ps of the light receiving unit 102.
It is incident on SD4a, 4b at the same time and causes crosstalk.

That is, the projection point (spot) of FIG.
When the distance measuring light is projected onto positions such as 150A and 160A, the ends of both PSDs 4a and 4b and the light receiving lenses 3a and 3a.
Since it is in the shaded portion 170 determined by the angle formed by b, the reflected light is incident on both PSDs 4a and 4b. Therefore, if light is projected onto the area of the shaded area 170 at the same time, P
The SDs 4a and 4b receive two signal lights at different points on the light receiving surface at the same time, and cannot output the correct signal light position signals of each, resulting in crosstalk.

Therefore, in the apparatus of this embodiment, as shown in FIG.
The distance measuring light is projected to a position outside the range of the shaded portion 170 such as the light projecting points (spots) 150 and 160 of No. 5, and the reflected light of the light projecting point 150 is the PSD 4a.
It does not enter the PSD 4b. Also,
The reflected light of the light projecting point 160 is incident only on the PSD 4b and not on the PSD 4a. In such a state, since the light receiving circuits 5a and 5b operate independently, it is possible to perform simultaneous two-point distance measurement without causing crosstalk even when two simultaneous points are projected.

In the present embodiment, the opening hole of the mask 31 of the apparatus of the present embodiment is arranged so that the distance measuring light can be projected to a position outside the range of the shaded portion 170 on the optical path diagram of FIG. The vertical distance between 31a and 31c, and the mirror 20a,
Set a slope of 20b.

As described above, in the apparatus of this embodiment, it is possible to effectively measure two points by projecting light once. However, in the case of the present embodiment, the subject distance L cannot be obtained from the equation (3) in the first embodiment described with reference to FIG. Therefore, the following arithmetic expression is used. Note that the respective projection angles are angles θ1 and θ2 as shown in FIG. 15, but this is determined by the angle between the opening holes 31a and 31c of the mask 31 and the principal point of the projection lens 7 in FIG.
The principle is the same as that described in.

The light projecting point 150 will now be described. The distance S between the principal points of the light projecting lens 7 and the light receiving lens 3a.
1, the signal light incident position x, the focal length fJ of the light receiving lens 4a, and the projection angle θ1 and the subject distance L satisfy the following equations.

L · tan θ1 = S1 + (x1 · L / fJ) Therefore, the subject distance L can be determined by L = S1 / (tan θ1− (x1 / fJ)) (5).

The above values θ1, S1, fJ are determined,
The value x1 can be detected by the PSD 4a and the AFIC (light receiving circuit 5a). The same applies to the light projection point 160, and the subject distance L can be calculated from the light incident position x2 on the PSD 4b and the known constant.

In the distance measuring operation of the distance measuring apparatus of the present embodiment having such a structure and principle, as the mask 31 is scanned in the direction of arrow X in FIG. 14, the opening holes 31a, 31 are formed.
By c, first, simultaneous light projection is sequentially performed on the upper and lower portions in the screen vertical direction, and subsequently, light is projected on the central portion in the screen vertical direction by the opening hole 31b. The opening holes 31a and 31c and the opening hole 31b are arranged at sufficiently separated positions, and when light is projected from the opening holes 31a and 31c, the opening hole 31b.
It is possible to prevent these distance measuring lights from simultaneously entering the same PSD and causing erroneous distance measurement due to crosstalk, by making sure that the light from the above does not enter the light projecting lens 7.

Therefore, by making the Xe tube 1 emit light in synchronization with the scanning movement of the mask 31, it is possible to measure the distances to the distance measuring points P1 to P6 in the screen 56 shown in FIG. The distance measuring points P1 to P arranged at the top and bottom of the screen
3 is projected at the same time and the distance is measured.

As described above, the feature of the distance measuring apparatus of the present embodiment is that the distance can be measured at two upper and lower points by one distance measurement, so that the time lag is further shortened and the distance can be measured at many points at high speed. It is a point that can be done. In addition, it is possible to take measures against energy consumption, which is the same as the device of the second embodiment shown in FIG.
When performing distance measurement of points, the total distance measurement can be completed by emitting light six times in the order shown in FIG. 16, which is advantageous in terms of time and energy.

(Supplementary Note) Based on the embodiment described above, the following distance measuring device for a camera can be proposed.

(1) In a distance measuring device for a camera having three or more distance measuring points in each of the short side direction and the long side direction of the photographing screen, the distance measuring calculation results at the respective distance measuring points are adjacent in the vertical direction. A distance measuring device for a camera, wherein focusing is performed only on two or more distance measuring points which are substantially equal to each other, and when the distance measuring points are not substantially equal, focusing is performed on the nearest distance measuring point. According to this device, a point adapted to the state of the subject to be used for photographing is designated as a distance measuring point, and good focusing suitable for the screen becomes possible.

(2) In the camera distance measuring device according to the above-mentioned appendix (1), the distance measuring point is limited to a predetermined area according to the vertical and horizontal postures of the camera and the focal length of the photographing lens. Ranging device. According to this device, the distance measurement points are limited by adapting to the camera posture at the time of shooting and the focal length of the shooting lens that has been set, making it possible to shoot in a focus state suitable for the shooting image frame. It is also possible to reduce the time required for.

(3) A light source, a light projection point switching means for sequentially projecting the light from the light source to different points on the photographic screen, and a pair of light receiving signal light reflected from the object of the projected light. In a distance measuring device comprising a light receiving means and a calculation control means for calculating a distance of an object according to a signal light incident position on the pair of light receiving means, the light source and the light projection point switching means are arranged to output a plurality of lights from the light source. A distance measuring device for a camera, comprising: a light projecting direction switching means for switching to the direction of the above and a scanning means for scanning the divided light in a direction substantially perpendicular to the dividing direction.

(4) In a distance measuring device capable of measuring a plurality of points on a photographic screen, the distance measuring points can be divided into two or more points in the vertical direction of the front and three or more points in the lateral direction. From the sensor and the above-mentioned three points arranged in the left-right direction of the screen, the selection control means for focusing the points showing the distance-measurement results of the two distance-measuring points above and below that are substantially equal. A distance measuring device characterized in that

(5) In a distance measuring device capable of measuring a plurality of points on a photographic screen, the distance measuring points can be arranged by dividing them by 3 points or more in the vertical direction of the screen and 3 points or more in the horizontal direction. The distance measuring sensor, the posture detecting means for detecting the vertical and horizontal postures of the camera, and the distance measuring result above the screen among the three points arranged in the vertical direction of the screen according to the output of the posture detecting means are invalidated. A distance measuring device for a camera, comprising: selection control means.

(6) In the above range (3), the light projection point switching means projects the light at a point where the pair of light receiving means can independently receive light at the same time.

[0085]

As described above, according to the distance measuring device for one camera of the present invention, the distance measurement of a plurality of points arranged two-dimensionally in the screen is performed with a simple structure at high speed and with high accuracy. Therefore, it is possible to reduce the time lag and the phenomenon of hollowing out. Moreover, power consumption can be suppressed by intermittently emitting light from the light source means. Further, according to another distance measuring device for a camera of the present invention, one distance data suitable for the photographing condition is selected from the distance measuring data of a plurality of distance measuring points to focus the photographing optical system. be able to.

[Brief description of drawings]

FIG. 1 is a block configuration diagram of a distance measuring device for a camera according to a first embodiment of the present invention.

FIG. 2 is an optical path diagram of a light receiving unit in the distance measuring device of the camera shown in FIG.

FIG. 3 is an optical path diagram showing a light receiving state when a light projecting point in a light receiving section in the distance measuring device of the camera shown in FIG. 1 is laterally displaced.

FIG. 4 is a diagram showing an example of a photographing screen showing distance measuring points in the distance measuring device of the camera shown in FIG. 1;

5 is a block configuration diagram of a light projecting unit and a CPU in the distance measuring device of the camera shown in FIG.

6 is a cross-sectional view of a mercury switch that is a posture detection unit applied to the distance measuring device of the camera of FIG.

7 is a time chart showing mirror scan and light emission timing in the distance measuring device of the camera shown in FIG.

8 is a diagram showing distance measuring points in the distance measuring device of the camera shown in FIG. 1;

FIG. 9 is a diagram showing an example of a shooting screen and a distance measuring point with respect to a camera posture and a zooming state in the camera distance measuring device of FIG. 1, wherein FIG. FIG. 9B shows a lateral posture in the telephoto state, and FIG. 9C shows a lateral posture in the wide angle state.

10 is a flowchart of a distance measurement processing operation in the distance measuring device of the camera shown in FIG.

FIG. 11 is a block configuration diagram of a light projecting unit of a distance measuring device for a camera according to a second embodiment of the present invention.

12 is an optical path diagram of a light projecting unit in the distance measuring device for the camera of FIG.

13 is a diagram showing distance measuring points in the distance measuring device of the camera shown in FIG.

FIG. 14 is a block configuration diagram of a distance measuring device for a camera according to a third embodiment of the present invention.

15 is an optical path diagram showing a light receiving state of a light receiving section in the distance measuring device of the camera shown in FIG.

16 is a diagram showing distance measuring points in the distance measuring device of the camera shown in FIG.

[Explanation of symbols]

1 ………………… Projecting element (light source means) 1a, 1b, 1c ………………… IRED (light source means) 3a, 3b …………… Receiving lens (a pair of light receiving means) 4a 4b ......... PSD (a pair of light receiving means) 5a, 5b ..... A light receiving circuit, AFIC (a pair of light receiving means) 8 ......... Rotating mirror (projection light scanning means) ) 9a, 23 ... Motor (projection light scanning means) 10a ... CPU (distance calculation means) 10b ....... CPU (selection means for selecting distance data) 21, 31 ............... Mask (projection light scanning means) 29 ............... Xe tube (light source means) 104 ............... Photography optical system P, P (1a) to P (5c) ), P1 to P9, 12, 12a,
12b ………………………… Distance measurement point

Claims (3)

[Claims] 1. A light source unit for projecting a plurality of light beams toward a subject, a projection light scanning unit for scanning a light beam emitted from the light source unit in a predetermined area in a screen, and a subject by the scanned projection light. A distance measuring device for a camera, characterized by comprising: a pair of light receiving means for respectively receiving and photoelectrically converting the reflected light of the above, and distance calculating means for respectively calculating a distance to a subject in response to the output of the light receiving means. apparatus. 2. The distance measuring apparatus for a camera according to claim 1, wherein the plurality of light beams emitted from the light source means emit light intermittently and sequentially. 3. A light source means for projecting a plurality of light fluxes toward a subject, a projection light scanning means for scanning light emitted from the light source means in a predetermined area in a screen, and a subject by the scanned projection light. A pair of light receiving means for respectively receiving and photoelectrically converting the reflected light, a distance calculating means for calculating the distance to the subject in response to the output of the light receiving means, and a plurality of distance data from the distance calculating means. Selection means for inputting and selecting only one distance data from the input data, and focusing the photographing optical system to a distance measurement point corresponding to the distance data selected by the selection means. Distance measuring device for cameras.