JP3337528B2 - Distance measuring device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an active distance measuring apparatus for projecting infrared light or the like toward a subject and measuring the distance to the subject by receiving light reflected from the subject.

[0002]

2. Description of the Related Art Conventionally, there are roughly two types of automatic focusing systems such as cameras. One is a passive method that measures the distance based on the luminance distribution information of the subject, and the other is an active method that measures the distance based on the reflected signal by projecting infrared light or the like to the subject. Was. Among them, the infrared light is projected toward the subject through the light projecting lens, and a predetermined distance from the light projecting lens, that is, from the subject to the semiconductor position detecting device via the light receiving lens provided at a position separated by the base line length. Auto-focusing (hereinafter referred to as AF) based on a so-called infrared active triangulation method in which reflected light is received and the subject distance is measured based on the incident position.
The device can be realized with a simple configuration, and is therefore used in many products.

In the case of an active AF device having a distance measuring zone only at the center of the screen, when there is no main subject in the projection direction, the AF device focuses on another subject or background, that is, at infinity. As a result, there is a drawback that the main subject is blurred out of focus (hereinafter referred to as a hollow shot). Therefore, in order to solve the above-mentioned problem, a so-called wide-field AF in which a plurality of projection signals for distance measurement are used to measure the distance of a plurality of object positions in a viewfinder.
Alternatively, a technique called multipoint ranging has been proposed, and a projection optical system required for this technique is disclosed in Japanese Patent Application Laid-Open No. Hei 4-248509.
No. has been proposed. Further, in recent years, zooming of a so-called compact camera using the above-described active AF device has been advanced. On the other hand, the demand for short-distance photography of a compact camera is also increasing.

[0004]

A multi-point distance measuring device is provided,
In a photographing apparatus equipped with a zoom that changes the focal length (angle of view) of the photographing lens, the distance measurement position on the image plane changes as the angle of view of the photographing lens changes. For example, even if the ranging position is set to a position that is effective in preventing hollowing at wide-angle, the distance between the ranging positions on the image plane is large at telephoto, and the effect of preventing hollowing is weakened. In addition, the phenomenon of focusing on an object other than the main subject is likely to occur. On the other hand, even if the distance measurement position is set to a position that is effective in preventing dropout during telephoto, at wide angle, the distance between the distance measurement positions on the image plane is too small, and the effect of multipoint distance measurement itself Becomes smaller.

An active AF device used in a camera or the like capable of switching between normal shooting and macro shooting is an active AF device in which a ranging zone is set at the center of the screen during normal shooting. Is used. However, even when switching to macro photography, since the optical axis of the photographing lens and the optical axis of the distance measuring device are substantially parallel at a distance from each other, distance measurement is not performed at the center of the screen during macro photography. The distance was measured farther away. Therefore, during macro shooting, focusing accuracy at the center of the screen was not very good.

The present invention has been made in view of the above-mentioned problems of the prior art, and has a simple configuration, has a small deterioration in optical characteristics and a small decrease in the amount of light, and easily emits light from a projection optical system. The method of changing the angle between a plurality of luminous fluxes has a high dropout prevention effect without being affected by the change in the angle of view of the photographing lens, and enables highly accurate ranging from a long distance to a short distance. An object of the present invention is to provide a distance measuring device.

[0007]

In order to achieve the above object, a distance measuring apparatus according to the present invention comprises a light emitting means and a projection master optical system for projecting light emitted from the light emitting means toward an object to be detected. the light receiving means for receiving light reflected by the object to be detected, and a light receiving optical system for condensing the reflected light on said light receiving means, is incident on the light receiving means reflecting
In a distance measuring apparatus for detecting a position of the detected object by an incident position of light, the light emitting unit includes a plurality of light emitting units.
And at least one of the light emitting units is disposed at a position distant from the optical axis of the projection master optical system for distance measurement.
With the projection light flux is made to be a plurality of light beams, an insertion retractable conversion lens group between the light emitting means and the projection master optical system, by inserting retraction of the conversion lens group, the rear principal Change the point position
Te, by injection direction of the light beam emitted from the light emitting portion disposed at a position away from the optical axis of the projection master optical system changes, the angle between the plurality of light beams each other
Change, and the conversion lens group
Irrespective of insertion and retraction of the projection master optical system and light emission
It is characterized in that the positional relationship with the means is fixed .
Further, the distance measuring apparatus according to the present invention includes a light emitting unit and the light emitting means.
Projection mass that projects light emitted from the step toward the object to be detected
Optical system and receives light reflected by the detected object
A light receiving means; and a light receiving means for collecting the reflected light on the light receiving means.
An optical optical system for inputting reflected light incident on the light receiving means.
Distance measuring device for detecting the position of the detected object based on the projecting position
In the above, the light emitting means may be at least one of light emitting units.
Is located at a position away from the optical axis of the projection master optical system.
And the light emitting means and the projection
Conversion that can be inserted and retracted from the master optical system
Having a lens group, inserting and retracting the conversion lens group
By changing the position of the rear principal point, the projection master
The light-emitting part disposed at a position away from the optical axis of the optical system
The direction of the emitted light beam changes so that
In spite of insertion and retraction of the conversion lens group,
The positional relationship between the projection master optical system and the light emitting means
The conversion lens group is retracted,
Or, projection in one of the inserted states
The light beam emitted from the master optical system is used for
The emitted light beam in the other state will be in the state for the short range
It is characterized by the fact that

Accordingly, the light beam emitted from the light emitting portion of the light emitting means is condensed by the projection optical system to become a substantially parallel light beam, and is projected from the projection optical system. At this time,
The projection light flux is substantially parallel to the line segment connecting the light emitting part and the position of the light emitting part side principal point of the projection optical system as described above. That is,
The light projection angle differs depending on the light emitting portion. In addition, in the state where the conversion lens is inserted and in the state where the conversion lens is retracted, by changing the position of the rear principal point, it is possible to change the angle of the projected light beam according to the distance between the light emitting part and the optical axis. The angle between the plurality of light beams can be changed. In the case of a zoom lens, it is desirable to reduce the angle between the projection light beams on the telephoto side, and to increase the angle between the projection light beams on the wide angle side. Furthermore, when increasing the accuracy on the telephoto side, the retracted state of the conversion lens is used for the telephoto range,
Also, it is desirable to use the state in which the conversion lens is inserted for a wide-angle region.

Hereinafter, the principle of the present invention will be described with reference to simple drawings. FIG. 6A shows a state corresponding to the telephoto range in which the conversion lens is retracted. For the sake of simplicity, the focal position f _1m is made coincident with the position of the light emitting portion S (b), and the light emitting portions S (a), S (b) and S (c) respectively correspond to the projection optical system. It is arranged on a line segment perpendicular to the optical axis. At this time, the light beams emitted from the respective light emitting portions are each emitted from the projection optical system as parallel light beams. The exit angle of each light beam (the angle between the light axis of the projection optical system and the optical axis) is equal to the angle between the line segment connecting the light emitting part side main point of the projection optical system and the light emitting part and the optical axis. In FIG. 6 (a), the angle between the light beam emitted from the light emitting portion S (a) and the optical axis is θ _1m , and the angle between the light beam emitted from the light emitting portion S (c) and the optical axis is θ _2m. As shown.

FIG. 6B shows a state in which a conversion lens having a positive refractive power is inserted, corresponding to a wide angle range. By inserting the conversion lens, the focal length of the projection optical system is shortened, and the light emitting portion S (b)
And the combined focal position f _{1c of} the master lens group and the conversion lens group, the light emitting site side principal point 6
(b) approaches the light emitting portion S (b), and the angles θ _1c and θ _2c formed between the projected light beams become larger than θ _1m and θ _2m shown in FIG. _6A . It is desirable that the light beam emitted from the projection optical system be a substantially parallel light beam, and that the light beam should be condensed at a distance where the main subject should exist. Under general photographing conditions, a main subject often exists at a photographing magnification of 1/30 to 1/100 except for a scene close to infinity where the projection light cannot reach. At the same magnification, the subject distance at the wide angle is shorter than the subject distance at the telephoto. Therefore, by appropriately arranging the focal position and the position of the light emitting part in each state, it is possible to meet the above-mentioned demand.

However, depending on the specifications of the camera system, the retracted state of the conversion lens can be used for a wide angle range, and the state where the conversion lens is inserted can be used for a telephoto range. By inserting, the focal length of the projection optical system may be set longer. The determination of which accuracy is to be set higher between the state for the wide angle range and the state for the telephoto range depends on the depth of field, the projection direction of the projected light beam, and the projection It is desirable to consider the relationship with the distance measurement target display and the like.

The projection optical system preferably comprises a projection optical system master lens group, a conversion lens group, and light emitting means. At this time, the light emitting means may include an optical element such as a lens. FIG. 7 is a diagram schematically showing an area of the projection light beam in a state where the conversion lens group is retracted. From this figure, it can be seen that the area of the projected light beam is smaller on the light emitting site side 22 than on the master lens group as compared with the subject side 21. Therefore, by making the configuration in which the conversion lens group can be inserted between the master lens group and the light emitting portion, the size of the conversion lens and the amount of movement during insertion and retraction can be reduced.

Further, the distance measurement accuracy can be improved by arranging such that the positional relationship between the projection optical system master lens group and the light emitting means does not change regardless of whether the conversion lens is inserted or retracted. In particular, in a system in which the conversion lens is retracted, a high-precision distance measurement can be realized only by adjustment at the time of manufacturing without a movable portion when switching the projection angle.

In order to adopt the above configuration, it is necessary to dispose an optical system that changes the focal length of the projection optical system and does not greatly change the rear focal position. FIG. 8 shows an example of a paraxial arrangement of the projection optical system master lens group and the conversion lens group at this time. In order to constitute a conversion lens group as shown in FIG. 8B with one refraction optical element (general lens), it is necessary to use a so-called meniscus lens. In addition, when a plurality of lenses are used, it is necessary to increase the distance between the projection optical system master lens group and the light emitting means, and a space for retreating the plurality of lenses is also required. As a result, the apparatus becomes large. However, a meniscus lens is a lens having a shape that is not suitable for giving a strong refractive power to the entire lens, while a conversion lens having a low refractive power cannot increase the change in the projection angle. . That is, if the negative refractive power of the concave surface is maintained to enhance the overall positive refractive power and the lens diameter is to be ensured, a large aberration occurs on the convex surface 41 as shown in FIG. However, the function as an optical element cannot be sufficiently performed.

Therefore, in order to configure the conversion lens group as shown in FIG. 8B with a single lens and to provide the conversion lens group with an appropriate refractive power, the conversion lens must have a Fresnel lens or It is desirable to use an optical element such as a diffractive optical element, which is a so-called plate lens surface having a macroscopic plane with a refractive power. The optical element having the plate lens surface,
As shown in FIG. 9B, a single lens can have relatively high refractive power while realizing the configuration of the conversion lens shown in FIG. 8B. That is, by using the optical element having the plate lens surface (DOE surface 42), regardless of whether the conversion lens is inserted or retracted,
A distance measuring apparatus having a simple configuration in which the positional relationship between the master lens group and the light emitting means does not change can be realized. Therefore, the number of parts is small, and the driving amount and weight of the conversion lens can be reduced, so that the cost in the device manufacturing process can be reduced, and the device can be easily assembled and compact.

When the plate lens surface is formed of a diffractive optical element, the diffraction efficiency can be improved by forming the diffractive optical element into a saw-like shape called a kinoform. Actually, a saw-like shape is expressed as a step
Often made with binary optics. Increasing the refractive power of the diffractive optical element increases the difference in the sawtooth pitch between the center and the periphery to improve the diffraction efficiency of the same order, making it difficult to manufacture and increasing the cost, such as lowering the yield. However, by changing the diffraction order between the central part and the peripheral part, the above-mentioned obstacle can be solved. For example, in the center, the first-order diffraction efficiency is almost 10%.
For example, it is set to 0%, and in the peripheral portion, the second-order diffraction efficiency is set to almost 100%.

[0017]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS First, an active triangulation for performing basic one-point ranging will be described. FIG. 5 is a block diagram showing a configuration of a main part of an automatic focusing camera for performing the active triangulation according to the present invention. In the figure, 11 is an IRED (infrared light emitting diode), 11a is an IRED control transistor, 12 is a light projecting lens for condensing a light beam emitted from the IRED 11, 13 is a subject, 14 is a light receiving lens, and 15 is a semiconductor. A well-known position detecting device (hereinafter, referred to as a PSD), 16 is an AF IC, 17 is control means for performing calculations for driving a focus adjustment lens, 18 is a driver, and 19 is a motor.

Since this apparatus is constructed as described above, the light beam emitted from the IRED 11
The light is condensed and irradiated toward the subject 13, and the reflected light is imaged on the PSD 15 by the light receiving lens 14. In PSD 15, photocurrents I ₁ and I ₂ according to the imaging position of the image is diverted, the photocurrent I ₁ and I ₂ are supplied respectively for AF IC 16. The AF IC 16 is connected to the IRED 1 via the IRED control transistor 11a.
1 is pulse-driven, and distance measurement data and reflection intensity data based on the photocurrents I ₁ and I ₂ sent from the PSD 15 are supplied to the control means 17. As described above, the distance measuring means in the present apparatus includes the IRED 11, the IRED control transistor 11a, the light projecting lens 12, the light receiving lens 14,
D15 and AF IC16. still,
The control means 17 has a built-in CPU. The output of the control means 17 drives a motor 19 serving as a power source for feeding out a lens by a driver 18.

The principle of operation of the infrared active triangular distance measuring device for measuring the object distance by the PSD 15 will be described below. When the optical axis of the light receiving lens 14 is made coincident with the center line of the PSD 15 and this is set as the origin, the reflected light incident position is x, the distance between the principal points between the light projecting lens 12 and the light receiving lens 14, that is, the base line length is w, Assuming that the focal length of the light receiving lens 14 is f, the distance d to the subject is given by d = w · f / x (1). Photocurrents I ₁ and I generated from PSD 15
₂ is proportional to the incident light intensity, but the photocurrent ratio I ₁ / I ₂
Does not depend on the incident intensity and is determined only by the incident light position x. Also, assuming that the total length of the PSD 15 is t, I ₁ / I ₂ = (t / 2 + x) / (t / 2−x) (2), and the above equation (1) is substituted into the equation (2). Then, I ₁ / I ₂ = (t + 2 s · f / d) / (t−2 s · f / d) (3) Therefore, if the photocurrent ratio I ₁ / I _{2 of} the PSD 15 is obtained, It can be seen that the distance d to the subject is uniquely determined.

FIGS. 1A and 1B show the configuration of an optical system according to a first embodiment of the present invention. FIG. 1A shows a state in which a conversion lens is retracted (a system corresponding to a telephoto range), and FIG. FIG. 3 is a diagram illustrating a state in which a lens is inserted (a system corresponding to a wide-angle region). In the state shown in FIG. 1A, the projection optical system master lens 1 composed of a convex lens and the light emitting part S (b) on the optical axis L and the optical axis L FIG. 2 shows a light emitting unit 4 including two light emitting portions S (a) and S (c) provided at positions away from the light emitting portion.

Therefore, the light beams emitted from the three light emitting portions S (a), S (b) and S (c) are converged by the package lens 2 and further condensed by the projection optical system master lens 1 to be substantially parallel. It is emitted as a luminous flux. At this time, the angle between the emitted light beams 8 (a), 8 (b) and 8 (c) and the optical axis L is paraxially the light emission of the combined optical system of the package lens 2 and the projection optical system master lens 1. It is determined by the inclination of a line segment connecting the element-side principal point 6 (a) and each light emitting portion. In addition, the parallelism of the emitted light beam 5 is improved as the distance between the light-emitting element side focal position of the combined optical system of the package lens 2 and the projection optical system master lens 1 and each light-emitting portion projected on the optical axis is shorter. Actually, the position slightly deviates from the value obtained paraxially due to aberration or the like, but the outline can be determined. It is desirable that the emitted light beam 5 be a slightly convergent light from a parallel light. In the case of the convergent light, the emitted light beam 5 has a magnification of the photographing lens of 1/100 to 1/30.
It is desirable to converge to a distance corresponding to In a numerical example to be described later, the paraxial distance is 5000 mm (about 1/50 times the focal length of the taking lens is 100 mm,
About 1/1 when the focal length of the taking lens is 50mm
(00 times), the light beam converged.

In the state shown in FIG. 1B, the projection optical system master lens 1 composed of a convex lens is arranged in order from the object side.
And a conversion lens 6 having a positive refractive power as a whole, which is a plate lens having a concave surface on the inserted subject side and a positive refractive power on the light emitting portion side, and the light emitting means 4. Optical system master lens 1
The positional relationship between the light emitting means and the light emitting means 4 is the same as that shown in FIG.

Accordingly, the light beams emitted from each of the three light emitting portions S (a), S (b) and S (c) are converged by the package lens 2 and the conversion lens 6 and further collected by the projection optical system master lens 1. Light beam 9 that is almost parallel
(a), 9 (b) and 9 (c) are emitted. At this time,
The angle between the emitted light beam 9 (b) and the optical axis L is paraxially the principal point 6 on the light emitting element side of the combined optical system of the package lens 2, the conversion lens 6, and the projection optical system master lens 1.
(b) and the inclination of the line segment connecting the light emitting portion 3.
The light-emitting element-side principal point 6 (b) is closer to the light-emitting portion side than the light-emitting element-side principal point 6 (a) shown in FIG.
The angle between (a), 9 (b) and 9 (c) is the luminous flux 8 (a),
8 (b) and 8 (c) are greater than the angle between each other.

The parallelism of the emitted light beam 5 is better when the distance between the focal position on the light emitting element side of the combined optical system of the package lens 2 and the projection optical system master lens 1 and each light emitting part projected on the optical axis is shorter. Become. In this case, as described above, a slight deviation actually occurs from the one obtained paraxially due to aberration or the like, but it can be roughly determined. It is desirable that the emitted light beam 5 be a slightly convergent light from a parallel light. In this case, the light emitting element side focal position of the combining optical system needs to be set closer to the subject than the light emitting part. In the case of convergent light, it is desirable that the exit light beam 5 converge to a distance corresponding to a magnification of the photographing lens of 1/100 to 1/30. In a numerical example to be described later, the paraxial distance is 3500 mm (about 1/70 times when the focal length of the taking lens is 50 mm, and about 1/100 times when the focal length of the taking lens is 35 mm). The convergence of the luminous flux is shown. Switching between the system for the telephoto range and the system for the wide-angle range may be arbitrarily determined by the photographer, or may be linked with zooming. Further, it is also possible to substantially measure five points by measuring the distance in both systems.

Table 1-1 shows optical data in the telephoto range, and Table 1-2 shows optical data in the wide-angle range. Where S (a), S (b)
The distance between them and between S (b) and S (c) is 0.685 mm, respectively.
In addition, the plate lens in Table 1-2 was designed by the ultra high index method. Aspherical surface coefficient of surface number 1 P = 0.1491, E = 0.55588 × 10 ⁻⁴ , F =
0.15566 × 10 ⁻⁵ , G = −0.97806 × 10
^-7

[0026] Aspherical surface coefficient of surface number 1 P = 0.1491, E = 0.55588 × 10 ⁻⁴ , F =
0.15566 × 10 ⁻⁵ , G = −0.97806 × 10
^-7 Refractive power of plate lens surface of surface number 4 1 / 6.023

In FIG. 2, (a) shows a distance in the telephoto range of 5000 mm (approximately 1/50 times the focal length of the photographing lens of 100 mm, and approximately 1/100 times that of the focal length of the photographing lens of 50 mm). (B) shows a wide angle range of 3500 mm (approximately 1/70 times the focal length of the photographing lens at 50 mm, and about 1/100 times at the focal length of the photographing lens of 35 mm). ) Are shown.

Numerical examples in the case where a lens having the same specifications as the optical system used for data extraction shown in Tables 1-1 and 1-2 are used, and a plate lens is also used as the master lens. These are shown in Tables 2-1 and 2-2 below.
FIG. 3 shows an example in which a conversion lens group constituted by a meniscus lens having the same specifications is inserted and designed. Aspherical surface coefficient of surface number 1 P = 0.1491, E = 0.55588 × 10 ⁻⁴ , F =
0.15566 × 10 ⁻⁵ , G = −0.97806 × 10
^-7 Refractive power of plate lens surface of surface number 2 1 / 3.438

[0029] Aspherical surface coefficient of surface number 1 P = 0.1491, E = 0.
55588 × 10 ^-4 , F = 0.15566 × 10 ^-5 , G
= −0.97806 × 10 ⁻⁷ Refractive power of plate lens surface of surface number 2 1 / 3.438 Refractive power of plate lens surface of surface number 4 1 / 4.942

Here, the shape of the aspherical surface in each of the above numerical examples is represented by the following equation using the above aspherical surface coefficients. Here, the coordinates in the optical axis direction are X, the coordinates in the direction perpendicular to the optical axis are Y, and the curvature of the apex of the aspheric surface is C (curvature = 1 / radius of curvature). ^{X = CY 2 / {1+ (} 1-PC 2 Y 2) 1/2} + EY 4 + FY 6 + GY 8 Note, plate lens surface may be constituted by a Fresnel lens.

Next, a second embodiment will be described. In FIG.
(A) shows the state in which the conversion lens is retracted,
(B) shows a state where the conversion lens group is inserted. In the optical system of the present embodiment, as shown in FIG. 4, a light-emitting portion is arranged at a position distant from the optical axis of the projection optical system, and either the retracted state or the inserted state of the conversion lens group is set. The luminous flux emitted from the projection optical system is used for a long-distance region in which the luminous flux is almost parallel to the optical axis of the photographic lens, and the area where the luminous flux intersects with the optic axis of the photographic lens in the other state is a short distance from the photographic lens It is configured to have a state for a short-distance region having a configuration set near the imaging region on the side. Even if the optical system is configured in this manner, it is possible to provide a focus detection device that can reduce the deterioration of the optical characteristics and decrease the amount of light and can measure the distance with high accuracy from a long distance to a short distance. In the case of this embodiment, only one light source of the projection optical system is sufficient.

[0032]

As described above, according to the distance measuring apparatus of the present invention, the angle formed between the plurality of light beams emitted from the projection optical system with little deterioration in optical characteristics and decrease in light quantity is small. Can be implemented to change
It has a high centering prevention effect that is not affected by a change in the angle of view of the taking lens. Further, according to the apparatus of the present invention, there is an advantage that, despite the simple configuration, the deterioration of the optical characteristics and the decrease in the amount of light are small and the distance can be measured with high accuracy from a long distance to a short distance. Have.

[Brief description of the drawings]

FIGS. 1A and 1B show a configuration of an optical system according to a first embodiment of the present invention, in which FIG. 1A shows a state where a conversion lens is retracted, and FIG. 1B shows a state where a conversion lens is inserted. is there.

2A and 2B are optical data according to the first embodiment of the present invention, wherein FIG. 2A is a projection intensity distribution diagram at a distance of 5000 mm in a telephoto range, and FIG. 2B is a projection intensity distribution diagram at a distance of 3500 mm in a wide-angle region. .

FIG. 3 is a diagram showing a design example in which a conversion lens group constituted by a meniscus lens is inserted with the same specifications as the optical system of the apparatus of the present invention.

FIG. 4 shows an optical system according to a second embodiment of the present invention;
(A) is a diagram showing a state where the conversion lens group is retracted, and (b) is a diagram showing a state where the conversion lens group is inserted.

FIG. 5 is a diagram illustrating a configuration of a main part of an autofocus camera including an active triangulation device that performs one-point ranging.

6A and 6B schematically show the configuration of an optical system in a focus detection device according to the present invention, in which FIG. 6A is a schematic diagram showing a state corresponding to a telephoto region in which a conversion lens is retracted, and FIG. 6B is a wide-angle region in which a conversion lens is inserted. It is a schematic diagram of a corresponding state.

FIG. 7 is a diagram schematically showing an area of a projection light beam when the conversion lens is retracted.

FIG. 8 is an example of a paraxial arrangement in which the positional relationship between the projection master lens group and the light emitting means in the optical system shown in FIG. 6 is fixed, and (a) is a diagram showing a state in which the conversion lens group is retracted; (b) is a diagram showing a state where a conversion lens group composed of one lens is inserted.

FIG. 9A is a shape diagram of a conversion lens having a strong refractive power according to the related art, and FIG. 9B is a shape diagram of a conversion lens group constituted by a single lens used in the apparatus of the present invention. .

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 Projection optical system master lens 2 Package lens 4 Light emitting means 5 Emission light beam 6 Conversion lens 8 (a), 8 (b), 8 (c) Light beam 9 (a), 9 (b), 9 (c) Light beam 11 IRED (Infrared light emitting diode) 11a IRED control transistor 12 light projecting lens 13 subject 14 light receiving lens 15 PSD 16 AF IC 17 control means 18 driver 19 motor 21 subject side 22 light emitting part side 31 shooting lens group 32 imaging lens group 41 imaging surface 41 convex surface 42 DOE plane d Distance to subject f _1m focal position f _1c composite focal position L optical axis S, S (a), S (b), S (c) Light emitting part θ _1m , θ _2m Emission light flux and optical axis Angle θ _1c , θ _2c Angle between projected luminous flux

Claims (2)

(57) [Claims] 1. A light emitting means, a projection master optical system for projecting light emitted from the light emitting means toward an object to be detected, a light receiving means for receiving light reflected by the object to be detected, and Yes reflected light and a light receiving optical system for focusing, the distance measuring device for detecting the position of the target object by the incident position of the reflected light incident on the light receiving means, said light emitting means, a plurality of light emitting portions And at least one of the light emitting units is disposed at a position distant from the optical axis of the projection master optical system, so that a plurality of projected light beams for distance measurement are provided.
Together so that a light beam, has an insertion retractable conversion lens group between the light emitting means and the projection master optical system, by inserting retraction of the conversion lens group, the change of the rear principal point position
The angle formed between the plurality of light beams is changed by changing the emission direction of the light beam emitted from the light emitting unit disposed at a position distant from the optical axis of the projection master optical system.
Is changed, and the insertion and retraction of the conversion lens group is
Without changing the positional relationship between the projection master optical system and the light emitting means.
A distance measuring device characterized by being constant . 2. Light emitting means and light emitted from the light emitting means.
A projection master optical system for projecting the object to be detected
Light receiving means for receiving light reflected by the detected object;
A light receiving optical system for collecting the reflected light on a light receiving means.
Depending on the incident position of the reflected light incident on the light receiving means.
In a distance measuring apparatus for detecting a position of an object to be detected , at least one of a light emitting unit and the projection unit may be configured to project the light from
To be located away from the optical axis of the master optical system
As well as, the withdrawal inserted between said light emitting means and the projection master optical system
The conversion convergence lens group
The position of the rear principal point is changed by inserting and retracting the lens group.
At a position distant from the optical axis of the projection master optical system.
The emission direction of the luminous flux emitted from the disposed light emitting unit is
And change the insertion and retraction of the conversion lens group.
Without changing the positional relationship between the projection master optical system and the light emitting means.
Constant, the conversion lens group is retracted, or
Projection master in one of the inserted states
The light beam emitted from the optical system is
The output luminous flux in the state is now in the state for the short range
A distance measuring device characterized by the above-mentioned.