JPS63289412A - Rangefinder for camera - Google Patents

Abstract

PURPOSE:To accurately measure a distance even when an object is present at any position on a photographing picture and to prevent photographing in a focus mismatching state, by projecting a plurality of slit like beams on the object and allowing the reflected beams from the object to be incident to photoreceptors arranged in a matrix form to perform predetermined close range processing. CONSTITUTION:A beam projecting part and a beam receiving part are arranged to the front surface of a camera body so as to be separated by a predetermined base line length from each other and beam is projected on an object from the beam projecting part while the reflected beam from the object is received by the beam receiving part to measure the distance between the beam receiving part and the object. At this time, the reflected beams 5A'-5C' of slit images 5A-5C, which has the width in the direction perpendicular to the base line length and are spread over the almost whole of a photographing picture, from the light source part 1 in the beam projecting part through the slit holes 2A-2C of a slit plate 2 are incident on the photoreceptor 9 of the beam receiving part arranged in a matrix form. The respective lines 9A-9C thereof output signals showing the beam receiving positions thereof. Further, when the output of the photoreceptor 9 is definite or more, it is judged that the object is present at a distance nearer than a distance measurable range to perform alarm processing.

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial Application Field) The present invention relates to fixing the subject of a camera, and particularly to preventing malfunctions in distance measurement and preventing the subject from reaching a distance closer than the measurable range. Concerning countermeasures in certain situations.

(Prior art) Cameras with built-in subject distance measuring devices are widely known, but with conventional devices, unless the subject is brought to the center of the shooting screen, it is often mishandled and cannot measure the distance correctly. . As an improvement on this, there is a method that attempts to widen the distance measurement area by making the light beam horizontally long or four characters long.

That is, as shown in, for example, JP-A-61-246612 and JP-A-61-246613,
A slit-shaped light beam with a width perpendicular or diagonal to the base line length is projected onto the subject, and the reflected light is received by an area sensor with multiple pixels arranged in a matrix to capture the subject at a close distance. A slit or liquid crystal is used to project a single character or X-shaped beam of light onto the subject, and the reflected light is received by a sensor with multiple pixels arranged in a matrix.
There is a method that measures the distance to the subject based on the light reception state.

All of these conventional devices aim to widen the range of distance measurement by widening the width of the light flux in the - direction or in two directions and projecting light onto the subject.
The 1-minute resolution is too small to cover the entire screen, and depending on the subject, it can be difficult to shoot, so it still cannot be said to be a one-minute solution.

Roughly speaking, even when the subject is closer than the measurable range, conventional methods have a minimum of 1ifi? In other words, there was a problem in that the shortest distance was read and the photograph was taken without the subject being in focus, resulting in an out-of-focus photograph.

(Object of the Invention) The present invention solves the above-mentioned conventional problems by devising the projection state of the slit-shaped light beam and performing appropriate processing based on the distance measurement result. This is a camera that can widen the distance measurement system and measure the distance accurately no matter where the subject is on the shooting screen, while also preventing shooting when the subject is out of focus. The purpose of this invention is to provide a subject distance measuring device.

(Structure of the Invention) The present invention has a light emitter and a light receiver arranged on the front surface of a camera body, separated by a predetermined baseline length, and reflected light emitted from the light emitter, reflected by a subject, and returned. is received by the light receiving section,
In the subject distance measuring device for a camera that measures the subject distance from the light receiving position, the light projecting section is configured to have a width in a direction perpendicular to the base line length and to project a plurality of slit-shaped light beams, In the light-receiving section, a plurality of light-receiving elements r are arranged in a matrix, each row of which is arranged substantially parallel to the slit-like light beam, and one light-receiving element is used for measurement with respect to one slit-like light beam. The light receiving element f corresponds to the reflected light from the subject within the possible distance range.
The sensor is arranged so that the object is incident on the object, and is further provided with means for performing predetermined close-range processing when it is determined that the object is closer than the measurable distance range.

With this configuration, the slit-shaped light beam is projected to spread across the entire shooting screen, increasing the ratio of one rear distance measurement to the shooting screen, and preventing the subject from falling through the shooting screen, no matter where it is located. Moreover, when the subject is closer than the measurable distance range, it is no longer possible to take a picture with the subject out of focus.

(Embodiment) FIG. 1 shows a schematic configuration of an object distance measuring device for a camera according to the present invention.

The basic configuration of this device is a light projecting section and a light receiving section, which are arranged on the front of the camera body with a predetermined baseline length apart.

In FIG. 1, a near-infrared light emitting diode, a flash discharge tube, etc. are used as a light source section 1, and a slit plate 2 and a floodlight lens 3 are arranged in front of this light source section 1, and a cylindrical concave lens 4 is arranged as necessary. will be distributed. The slit plate 2 is
A plurality of wide slit holes 2A and 28.2C are arranged on the focal plane of the light projecting lens 3 in a direction perpendicular to the base line length, and are arranged side by side in the base line length direction (three in this case), and are spread out with respect to the photographing screen. ), and the area other than the slit hole is designed to block light.

Further, in order to reduce the aberration of the light beam, the slit plate 2 is slightly curved as shown in the figure.

The light beam projected from the light source section 1 passes through the slit plate 2 and is divided into three beams having widths perpendicular to the base line length. This slit light beam passes through the projection lens 3 and is projected toward the subject. 5A, 5B, and 5C show the slit images.

Here, the dotted line portions of the slit images 5A, 5B, and 5G are the distance measurement points on the shooting screen when shooting with a wide-angle lens when the shooting lens of the camera is a bifocal or zoom lens.
Since the ratio of 1 to 2 is small, the width of the slit luminous flux is widened to compensate for this. Increasing the width of the slit light beam can be achieved by placing the cylindrical concave lens 4 in front of the projection lens 3 so that the axis of rotation of the cylindrical surface is perpendicular to the wide direction of the slit hole.

The reflected lights 5A', 5B', and 5C' of the slit luminous flux projected toward the subject pass through the light receiving lens 7 and the aberration correction concave lens 8, and are incident on a light receiving element 9 such as a position sensor (PSD). Here, if a cylindrical concave lens 4 is inserted in front of the light emitting lens 3 in order to expand the width of the slit light beam, a cylindrical concave lens 6 is also inserted in front of the light receiving lens 7 on the cylindrical surface in order to correct the expanded portion. Place it so that the axis of rotation is perpendicular to the wide direction of the reflected light.

FIG. 2 shows the light-receiving element 9 and the reflected image incident on the light-receiving element 9.

In the figure, reflected images 5A' and 5B' are shown in the shaded areas.

Light reception %F9A, 9B corresponding to 5G' respectively.

9C is placed. These light receiving elements 9A and 9B.

9C is divided into n pieces in the wide direction of the reflected images 5A', 5B', and 5G', and each of the light receiving elements 9A1 to 9An
19B1 to 9Bn19C1 to 9Cn independently output a signal indicating the light receiving position.

The configuration of the light receiving element F (If? sensor) will now be explained with reference to FIG.

In the figure, a resistor 50 is formed on the surface of the light receiving element, and when light is incident on this resistor 50, currents IA and IB flow from the incident position of the light to the multi-current TFJs 51A and 51B, respectively. . Here, if the length between the electrodes 51A and 518 is 11 and the resistance is RLl, the length between the electrode 51A and the light incident position is χ, and the resistance is R, then when light enters a certain position on the light receiving element The output currents IA and I
The relationship between B is as follows.

I To (RR)/RL.

A L χ 1B=IO'R, c/RL (However, I o = I A + l B) Here, if the length and resistance value are proportional, IA=Io (1, -χ)/L, IB=lo * ,z/
l-,', IA/IB=(L-χ)/χ Therefore, by finding the ratio of the output currents I and IB from the above equation, the incident position of the light on the photodetector can be determined regardless of the incident energy. It turns out.

Next, the principle of the device of the present invention will be explained.

3 and 4 show the functional configuration of this device. In the figures, slit-shaped light beams projected from slit holes 2A, 2B, and 2G pass through the projection lens 3, and the objects 20, 21, 2
2, the reflected light passes through the light receiving lens 7,
Light receiving elements 9A, 9B.

It is incident on 9C. Here, when the subject 20.21° 22 is within the autofocus (AF) measurable distance range (the range from the closest distance to infinity where the distance to the subject can be measured), the slit hole 2A.

The reflected light of the slit-shaped light beam projected from 28.2C is incident on the corresponding light receiving elements 9A, 9B, and 9C, respectively. Since the slit image moves on the light-receiving element according to the distance to the subject, the subject distance can be measured for each distance measurement based on the principle of triangulation. After this measurement, an instruction is issued to, for example, focus on the closest subject. The subject is AFed here.
The number of slits and the spacing between them are designed so that when the distance is within the measurable distance range, the reflected image from the subject will not enter any light receiving element other than the corresponding light receiving element.

FIG. 3 shows a case where the subject is within the possible AFF distance range, and FIG. 4 shows a case where the subject is closer than the possible AFF distance range. In FIG. 4, the slit-shaped light beam projected from the slit hole 2B passes through the projection lens 3 and reaches the subject 21, which is closer than the AF measurable distance range.
At this time, the reflected light passes through the light receiving lens 7 and enters the light receiving element f.

Here, the reflected light from the slit hole 2B should originally be incident on the corresponding light receiving element 9B, but since the subject 21 is on the 6 nearer side than the AF rangefinder possible distance range, the light receiving element 9B The light does not enter into the adjacent light receiving element 9C. In this case, the output of the light-receiving element 9 will be larger than normal, so if the output is above a certain value, it is assumed that the subject is closer than the shortest shooting distance of the photographing lens, and the subject is in a different area, for example. It performs processing such as adjusting the distance or issuing a short-range warning.

Figure 5 shows the relationship between the amount of light received on the light receiving element and the distance.As shown in the figure, the amount of light received on the light receiving element 25i increases as the closer the distance, so the subject falls within the AF distance range as described above. Because the distance is closer than that, even if the reflected light that should originally enter the light receiving element 9B enters the light receiving element 9C, the output of the light receiving element r90 will be larger than normal, so if the output exceeds a certain value, the subject will be It is possible to judge that the object is closer than the shortest shooting distance and process it.

Next, the relationship between the slit interval χ and the position of the reflected image on the light receiving element will be explained using FIGS. 6 and 7.

In FIG. 6, the slit-shaped luminous fluxes projected from the slit holes 2A, 2B, and 2G pass through the projection lens 3 to the subject 2.
0.21.22, and the reflected light passes through the light receiving lens 7.
and enters the light receiving element 9.

Further, FIG. 7 shows the relationship among the light receiving lens 7, the light receiving element f-9, the reflected light flux, and the amount of light received on the light receiving element 9 25.

In these figures, χ Nislit hole spacing y = position of the reflected image on the light receiving element Il: base line length (distance between the center axes of the projecting and receiving lenses) f: focal length of the projecting and receiving lenses; Assuming that the distance to the subject is γ, the amount of movement γ of the reflected image on the light-receiving element is determined by the following equation.

'F-11-f/L+χ ・・・・・・・・・(
1) Determine the position γ on the light-receiving element by entering specific values from equation (1) above. Now, suppose the baseline length ρ=301'am
], the focal length of the projection/reception lens is 1f=171ml.

In FIG. 6, if go is the position on the light receiving element of the reflected light of the luminous flux projected toward the subject at an infinite distance from the slit hole 2B located on the optical axis of the light projecting lens,
Since the slit hole 2B is located on the optical axis of the projection lens,
χ−〇1 Also, since the image is projected onto an object at an infinite distance, l
->oo.

Substituting these into equation (1) yields γ0=0. Let this position be Yo.

Next, when the light flux from the same slit hole 2B is reflected by an object at a distance of 5 m, and if the amount of movement of the reflected light from the position Yo on the light receiving element is 4N', then 411' = 30X1 715x103 +0
=0. 102[a+s+1 In other words, when the subject approaches from infinity to a distance of 5m -
), the position of the reflected light on the light receiving element is 91' = 0.10 in the direction away from the light emitting part in the baseline length direction from the YO position.
2 [move sl.

Similarly, the slit-shaped light beam from the same slit hole 2B is AFed.
The amount of movement of the reflected light from position 19Yo on the light receiving element when reflected by the subject at the closest measurable distance (the shortest distance to the subject that can be measured, assuming = 0.5 [ml) is lyl and J, ri1=30X1710.5X1
03 MO-1゜02[m:1 Therefore, the subject is within the AF measurable distance range from infinity to the closest A'F measurable distance (temporarily L = 0.5 [ml]). At this time, the reflected light from the subject is within the range of 1,02[,#l#l] from the position Yo of the light receiving elements to the position 1,02 [, #l#l] in the direction away from the light emitting part in the baseline length direction. Move accordingly.

Next, the reflected light of the slit-shaped light flux projected toward the subject at infinity from the slit holes 2A and 2C, which are a distance χ in the base line length direction from the slit I-hole 2B, is reflected at a position 1t on the light receiving element.
The beam is incident at a position 4/2 wider than Yo. If g2 is calculated from equation (1), the subject distance I-→■, so g2
= χ is obtained.

Similarly, the closest distance that the subject can be measured by AF (L = 0.5
[m]), the reflected light also enters a position separated from the position YO on the light-receiving element by the value determined by equation (1). When calculating the value, from equation (1), /! /2 =30X1710.5x103+χ-χ+1
．． 02[a] From these facts, as shown in FIG. 7, the movement of the anti-01 image of the object from the closest distance to infinity on the light receiving element is '!', regardless of the position of the slit light source. 11=1.
02 [m].

Now, in order to prevent the reflected light from the subject of the slit-shaped light beams from adjacent slit holes from overlapping on the light receiving element in the AF distance measurable distance range, the slit interval χ is set as follows: 1 must be satisfied.

First, in Fig. 7, in order not to overlap on the light receiving element, Y2 > 4N → y3 + d + α ・・・・・・・・・
(2) However, /y3: Distance between light receiving elements 1 d Width of slit hole α: The relationship must be the spread of reflected light caused by lens aberration or blurring of the slit. Here, LT11=1゜0
2 [carp], 92-χ, so equation (2) becomes as follows.

χ>1.02 [1111111-1q3 +d-+α
--------(3) In order to perform accurate distance measurement, the condition of equation (3) above must be satisfied.

Next, in order to satisfy the above conditions in Figures 8 to 15,
An example will be shown in which the distance measurement area is further expanded by setting the slit hole interval and devising the slit shape to prevent the slit from passing through.

FIG. 8 shows the arrangement of slit holes on the slit plate 40,
FIG. 9 shows the light receiving element 41 and the reflected image on the light receiving element.

In FIGS. 8 and 9, the slit holes 40A to 4ON are arranged, for example, in a staggered manner so as to cover almost the entire photographing screen, and the slits emitted from each of these slit holes Reflection image 40A' of shaped luminous flux
4ON' are corresponding light receiving elements 41A to 41N, respectively.
Move above according to the distance of the subject.

Next, the photographing screen and the position of the reflected image of the slit-shaped light beam on the light receiving element will be specifically explained using FIGS. 10 to 15, assuming an actual photographic scene.

In FIG. 10, the subject is located slightly to the right of the center of the shadow screen 45. Slit-shaped light beams 42A to 42N are projected onto this photographic screen as shown in the figure. FIG. 11 shows the incident position on the light receiving element of the reflected light of the projected slit-shaped light beam from the subject. Since the object A is at a short distance of several meters, the anti-It images 401' and 40J' of the slit-shaped light beam reflected by the object A are incident on the short distance side of the corresponding light receiving elements 411 and 41J, respectively. For other slit-shaped light beams, the subject is at an infinite distance, so the reflected light does not return. Therefore, the distance to the subject A is measured from the position of the reflected light on the light receiving element, and the signal is transmitted to the photographic lens system.

Further, the example shown in FIG. 12 is a case where the subject B is behind the subject A, and a slit-shaped light beam is projected onto the photographing screen 45 as shown in the figure in the same manner as above.

Each of the projected slit-shaped light beams hits the subject and is reflected, and the reflected light is incident on the corresponding light receiving element at a position corresponding to the distance from the subject, as shown in FIG. The reflected light of the slit-shaped light beams that did not hit the subjects A and B does not return because the subject distance is infinite, as described above.

Each light receiving element determines the subject distance for each distance measurement area from the position of the reflected image. And each photodetector f
It compares the output of the two and sends a signal to focus on the closest subject.

Next, FIGS. 14 and 15 show examples when the subject is closer than the AF measurable distance range.

In FIG. 14, a subject C is a subject that is closer than the measurable distance range. In this case, as shown in FIG. 15, the reflected images from the subjects A and B are incident on the corresponding light receiving elements, as in the example described above. However, the reflected light image 400' in which the slit-shaped light beam 42D is reflected by the subject C does not enter the corresponding light receiving element 41D.
The light is incident on the adjacent light receiving element 41E. Therefore, two reflected lights, the reflected light image 40E' and the first reflected light image 40D', of the slit-shaped light beam 42F are incident on the light receiving element 41E, and the output of this light receiving element 41 becomes larger than normal as described above. Therefore, processing is performed on the assumption that the subject is closer than the shortest photographing distance ll1lt.

Next, the III control procedure of the apparatus of the present invention will be explained using the flowchart shown in FIG.

In the figure, after the start of the operation in #101, the light receiving element receives reflected light from the subject, and in #102, the subject distance of each distance measurement area is determined.

Then, in #103, it is determined whether the output of each light receiving element, that is, the amount of light incident on each light receiving element is all below a reference level according to the subject distance.

If the outputs of all the light-receiving elements are below the reference level, the one with the closest subject distance is selected during each distance measurement rear in step #104, and the photographing lens drive motor is driven in step #105. However, if the output of any one of the light receiving elements is higher than the reference level in the judgment of #103, it becomes #1.
At step 06, a short distance warning is given to the photographer.

Here, regarding the reference level used for the determination of #103, the first
This will be explained using Figure 8.

This figure is a graph showing the relationship between the subject distance and the light receiving element f output reference level. Since the amount of light reflected from the object generally decreases in inverse proportion to the square of the distance, the output of the light receiving element f also decreases according to the distance to the object. Therefore, if you know the subject distance, you can roughly know the output of the light receiving element, so you can set the level in advance, and if the output of the light receiving element is larger than the reference level corresponding to the closest distance that can be used for AF distance measurement, use the method described above. 20 subjects to be measured using the adjacent distance measuring J rear
It is determined that they are in one piece and that they are closer than the AF measurable distance range.

Next, FIG. 19 shows a block configuration of this apparatus that executes the flowchart shown in FIG. 17 above.

In the figure, when the release switch 61 is turned on, the trigger circuit 62 is activated and a signal is sent from the microphone 63 to the light emitting element drive circuit 64, causing the light emitting element f of the light source section 1 to emit light. The light beam emitted from the light source 1 is the subject (not shown).
The light is reflected by the light receiving elements 41A to 41N.

When light enters the light-receiving elements 41A to 41N, a current II flows through the output terminals corresponding to the light incident position.
・B: 1A/■8 (distance), IA+ by optical element processing circuit 65
It is output in the form of IB (incidence light intensity) and held by the sample and hold circuit 66 at the timing of light emission from the light source section 1.

The output lA/■B of each light-receiving element processing circuit 65 held by the ripple hold circuit 66 is sequentially A/D-converted by the A/DJ converter 68 via the nurujiprek 1/noro 7, and converted into the A/D-converted data. Based on this, the microphone 63 calculates the object distance for each distance measurement.

Thereafter, for each distance measurement area, the outputs iA+IB of the light receiving element processing circuit 65 are sequentially read out through the full diplexer 4noro 9, and the distance is determined according to the nearest possible distance for AF distance measurement stored in the RAM 70. Compare with reference level. And the output IA+I of all the light receiving element processing circuits 65
If B is less than the reference level corresponding to the closest distance, the one with the closest subject distance is selected from among the distance measurement areas. Then, the lens drive motor drive circuit 72 is controlled by the microcomputer 63.
A signal is sent to drive the photographic lens, and when the subject is in focus, the photographic lens is stopped.

If here, the output IA + of each light receiving element f processing circuit 65
If there is a value at or above the standard level corresponding to each subject distance in Ia, the microcomputer 63 determines that the subject is in AF as described above.
It is determined that the distance is closer than the measurable distance range 1, and a signal is sent to the warning lamp lighting circuit 71 to issue a short distance warning. This is the first example of close-range processing when the subject is closer than the measurable distance range. This processing can prevent photographing in an out-of-focus state.

Next, another embodiment will be described using the flowchart of FIG. 20.

This example also has a movement amount of #111 like the previous example! i8
After (start), the light receiving element receives reflected light from the subject, and in step #112, the subject distance of each distance measurement area is calculated. Then, in #113, it is determined whether the output of each light receiving element, that is, the amount of light incident on each light receiving element is all below a reference level according to the closest distance.

If the output of all the light receiving elements is below the MjII- level, in step #114 the one with the closest object distance in each distance measurement area is selected, and in step #115 the photographing lens drive motor is driven. However, if the output of any one of the light receiving elements r is larger than the reference level in the judgment in #113, then in #116, select the object from the one whose light receiving element output is below the reference level in each distance measurement process 7. The object with the closest distance is selected, and in step #115, the photographing lens drive motor is driven so as to focus on the object of distance measurement 1-7. This is a second example of close range processing. This makes it possible to prevent photographing errors in the same way as described above.

In addition to the above-mentioned embodiments, in a camera that can take pictures even in the macro area, when the subject is closer than the AF distance measurable distance range, it is also possible to move the photographing lens to the macro area. It is possible. This allows the camera to accurately focus on the subject intended by the photographer.

The 70=diat of this example is shown in FIG.

In the same figure, after the start of operation #121 as described above, the light receiving element receives the reflected light from the subject, and #
At step 122, the subject distance for each distance measurement area is calculated. Then, in step #123, it is determined whether the outputs of each light receiving element, that is, the amount of light incident on each light receiving element are all below the reference level. If the outputs of all the light-receiving elements are below the reference level, in #124 the one with the closest subject distance is selected from among the distance measuring units 1 to 7, and in #125 the Odori lens drive motor is driven.

Here, if any one of the light receiving element outputs exceeds the reference level according to the subject distance in the level judgment in #123, then in #126 it is determined that the subject is closer than the AF measurable distance range. Then, in step #127, in the distance measurement area exceeding the reference level, the distance output obtained from the light receiving element output is multiplied by a conversion coefficient k to convert the distance of the object closer than the AF rangefinder possible distance range. Then, in #128, the closest one is selected from each area, the lens is brought to the macro area in #129, and the lens drive motor is driven in #125.

Here, a method of calculating the subject distance when the subject is at a distance closer than the AF measurable distance range will be explained using FIG. 22.

Originally, when the subject is within the AF distance range, the reflected light from the subject is reflected by the corresponding light receiving elements 9A and 9B.
, 9G, but as mentioned above, if the subject is closer than the AF measurable distance range,
The reflected light incident on the light receiving element 9A is reflected from the neighboring light receiving element 7-98.
incident on . As a result, as shown in FIG. 23, reflected light 25A originally corresponding to the light receiving element 9B and reflected light 25B corresponding to the light receiving element 9A are simultaneously incident on the light receiving element 9B.

Therefore, as the output of the light receiving element 9B, the output of the light receiving element 9B is
Reflected light 2 that originally corresponds to reflected light 25B that should be incident on A
Because it is extremely strong against 5A, the reflected light that originally corresponds to 25
The reflected light is hardly affected by the reflected light 25B and exits at a position slightly closer to the incident position of the reflected light 25A (the position indicated by the dotted line in FIG. 23).

However, in this state, the same output as when the reflected light corresponding to the normal light receiving element 'f9B is incident is output, so by multiplying this output by a certain conversion coefficient k, the output is outputted to the light receiving element 9A. The object distance within one corresponding distance measurement rear can be calculated. It should be noted that the above-mentioned conversion coefficient differs somewhat depending on the position of each light-receiving element.

In addition, since the structure is configured to project multiple slit-shaped light beams, it is possible to project the slit-shaped light beams onto the shooting screen as a whole. Even if you change the position and take a picture, there will be fewer pauses, and there is no need to align the focus mark in the center of the screen with the subject as in the past, allowing you to focus only on the composition. .

(Effects of the Invention) As described above, according to the present invention, a plurality of slit-shaped light beams are emitted, each having a width perpendicular to the base line length, and a plurality of light receiving elements arranged in a matrix. Each slit-shaped light beam is arranged so that the reflected light from the subject within the measurable distance range is incident on the corresponding light-receiving element. Even if there is a subject in the frame or a relatively small subject, the occurrence of missing objects is reduced, accurate distance measurement is possible, and one light receiving element ( position sensor) is corresponding, so
Distance measurement can be performed independently using each slit-shaped light beam, and distance measurement errors are reduced. Furthermore, when it is determined that the subject is closer than the measurable distance range, predetermined close-range processing is performed, which prevents taking pictures out of focus. ,
No more shooting mistakes.

[BRIEF DESCRIPTION OF THE DRAWINGS] Fig. 1 is a perspective view showing the general basic configuration of an embodiment of the object distance measuring device for a camera according to the present invention, and Fig. 2 shows a light receiving element in the device and a reflected image incident on the device. Figures 3 and 4 are plan views for explaining the removal of the device of the present invention, Figure 5 is a diagram showing the relationship between the amount of light received on the light receiving element and the distance, and Figure 6 is a diagram showing the relationship between the slit hole spacing and light reception. FIG. 7 is a diagram showing the relationship between the position of the reflected image on the element, FIG. 7 is a diagram showing the relationship between the light receiving position on the light receiving element and the amount of light received in the case of FIG. 6, and FIG. A diagram showing the arrangement shape, FIG. 9 is a diagram showing the light receiving element in the case of the slit shape in FIG. 8, and a reflected image on the same element, and FIG. 10 is a diagram showing an example of the photographing screen.
Fig. 11 is a diagram showing the light receiving element and the reflected image on the same element in the case of the photographing screen of Fig. 10, Fig. 12 is a diagram showing an example of another photographing screen, and Fig. 13 is the photographing screen of Fig. 12. Figure 14 is a diagram showing the light-receiving element and the reflected image on the same element in the case of , Figure 14 is a diagram of the shooting screen when some subjects are closer than the measurable side 1Ilt range, and Figure 15 is 14 is a diagram showing a light receiving element and a reflected image on the same element in the case of the photographing screen, FIG. 16 is a cross-sectional configuration diagram of the light receiving element, FIG. 17 is a flowchart showing an example of the control procedure of the device of the present invention, and FIG. 18 19 is a diagram showing the relationship between the subject distance and the output level of the light receiving element, FIG. 19 is a block diagram showing an example of the specific circuit configuration of the device of the present invention, and FIG.
21 is a flowchart showing another example of the control procedure, FIG. 21 is a flowchart showing still another example of the control procedure, and FIG.
2 and 23 are diagrams for explaining the procedure for calculating object distances when some objects are located at a distance closer than the measurable distance range, respectively. DESCRIPTION OF SYMBOLS 1... Light source part, 2... Slit plate, 3... Light projecting lens (the above constitutes a light projecting part), 7... Light receiving lens, 9
... Light-receiving elements (the above constitute a light-receiving section), 2A, 2B. 2C...Slit hole, 5A', 5B', 5G'.
...Reflected light, 20.21.22...Subject, 40...
・Slit plate, 40A~4ON...Slit hole, 41
... Light receiving element, 41A to 41N... Light receiving element, 40
A'~4ON'... Reflected image, 45... Shooting screen,
42A to 42N...Slit-shaped light flux, Ω...Base line length, 63...Microcomputer, 65...Light receiving element processing circuit,
71... Warning lamp lighting circuit, 72... Lens drive motor drive circuit. Patent applicant Minolta Camera Co., Ltd. Representative
People Patent Attorney Etsu Kotani Shunma
Chief Patent Attorney 1) Masamukai Patent Attorney Yasuo Itaya Procedural Amendment (Spontaneous) July 14, 1988 1. Display of the case □ 1988 Patent Application No. 124192 2. Name of the invention Camera object distance measurement Device 3, relationship with the person making the amendment Patent applicant name (6071 Minolta Camera Co., Ltd. 4,
Agent 5, Date of amendment order Voluntary amendment 6, Detailed explanation of the invention column 7 of the specification subject to amendment, Contents of amendment (1) “Pixels” in lines 10 and 15 of page 3 of the specification
is corrected as "light receiving element". (2) Correct the "aberration of the light beam" on page 6, line 19 of the same page to "blurring of the slit reflected image off-axis due to the aberration of the projection lens 3." (3) On page 6, line 20, correct "as shown" to "for example, in a concave shape in the direction that corrects the above-mentioned brush."

Claims (1)

[Claims] 1. A light emitter and a light receiver are arranged on the front of the camera body with a predetermined baseline length apart, and the reflected light emitted from the light emitter, reflected by the subject, and returned is collected. In a camera subject distance measuring device that receives light at a light receiving part and measures a subject distance from the light receiving position, the light projecting part has a width in a direction perpendicular to the base line length, and a plurality of slit-shaped light beams are projected. The light-receiving section has a plurality of light-receiving elements arranged in a matrix, each row of which is arranged substantially parallel to the slit-like light beam, and one light-receiving element per slit-like light beam. When the light-receiving elements are arranged so that reflected light from a subject within the measurable distance range is incident on the corresponding light-receiving element, and it is determined that the subject is closer than the measurable distance range. A subject distance measuring device for a camera, characterized in that it is provided with means for performing predetermined close distance processing. 2. The object distance measuring device for a camera according to claim 1, wherein the light projecting section is composed of a light source, a slit plate, and a lens, and projects the entire slit-shaped light beam in one light emission. 3. The object distance measuring device for a camera according to claim 1, wherein the light projecting section can be equipped with a cylindrical concave lens for extending the width of the slit-shaped light beam. 4. The object distance measuring device for a camera according to claim 1, wherein the determination as to whether or not the object is at a distance closer than the measurable distance range is made based on the output of the light receiving element.