JPH01291112A - Range finder - Google Patents

Abstract

PURPOSE:To find the range of an object existing in a wide range by changing the position and the direction of an emission of an auxiliary light projecting device against an optical axis of an image forming optical system. CONSTITUTION:An auxiliary light projecting means 4 consists of an auxiliary light projecting means 4A installed in a flash device and an auxiliary light projecting means 4B installed in a body, and they project auxiliary luminous flux La, Lb to an incident luminous flux area Lf by a focus detection use optical system. The luminous flux Lb is stopped down more than the luminous flux La and projected to a narrow area. As for the device 4B, the position and the direction of an emission are changed against an optical axis Op by a projection changing means consisting of an adjusting screw and an eccentric screw, therefore, although there is a parallax between an optical measuring means and the device 4, the position where the luminous flux Lb of a detection pattern intersects with the light beam Lf can be changed along the far and near direction against the range finder. Accordingly, even if a projection angle of the detection pattern is small, the projection can be executed in a state that the luminous flux Lb from the detection pattern projected to various objects position in a wide range containing the objects positioned extending from a near part to a distant part is contained in an area to be measured of the measuring means.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a distance measuring device, typified by a focus detection device for detecting the focus adjustment state of a photographing lens with respect to a subject in a camera, and is particularly applicable to low-luminance The present invention relates to a distance measuring device having a configuration for projecting a detection pattern for assisting distance measurement at certain times.

More specifically, an optical measuring means is provided to measure the distance to the object using an image of the object formed through an imaging optical system on a group of light receiving elements arranged in a row. An auxiliary light projection device for projecting a detection pattern for distance measurement assistance in which bright areas and dark areas are arranged alternately along the direction in which the light-receiving element group is arranged is located at a position distant from the optical axis of the imaging optical system. A distance measuring device comprising: an object brightness detection means for detecting the brightness of the object; and an auxiliary light projection control means for controlling the operation of the auxiliary light projection device based on the detection result of the object brightness detection means. Regarding.

[Conventional technology]

A typical example of this type of distance measuring device divides a beam of light from a subject that has passed through a photographic lens into two, and forms an image on each row of light-receiving elements provided at positions corresponding to the film surface. Focus detection uses a focus detection optical system and individual output signals from the pair of light-receiving element arrays to calculate the deviation from the in-focus position of the photographic lens with respect to the subject from the phase difference between the generated force signals. This device is incorporated into a camera as a focus detection device of a phase difference detection method, which together constitutes an optical measuring device.

The camera focus detection device using the phase difference detection method described above detects the output signals obtained from the phase difference between the output signals from a pair of light receiving element arrays that separately receive two light beams divided by the focus detection optical system. Since the deviation from the focus position of the subject, which is the object of the photographing lens, by the focus detection means is calculated based on the correlation between Unless the images have a certain degree of contrast, the correlation between them will not be significant and reliable focus detection will be difficult to achieve. However, if the brightness of the subject is below a certain level, the contrast of the subject image for focus detection will fall below a level that allows focus detection. Therefore, by forcibly creating contrast on the subject by projecting the detection pattern using the auxiliary light projection device, a state in which focus detection is possible is created.

Conventionally, the above-mentioned auxiliary light projection device is configured by: an auxiliary light source such as an LED; a transparent film printed with a striped pattern corresponding to the detection pattern and disposed in front of the auxiliary light source;
Further, it is known that a projection lens is disposed in front of the transparent film and is fixed in position on a camera body or the like.

[Problem to be solved by the invention]

However, the conventional distance measuring device described above has the following problems.

In other words, since the auxiliary light projection device is located at a distance from the optical axis, there is a parallax between the optical measurement means and the auxiliary light projection device, and the detection projected by this type of auxiliary light projection device Distance measurement operation using patterns as an aid,
When attempting to perform this on a wide range of objects, from objects located nearby to objects located far away,
It is conceivable to increase the projection angle of the detection pattern so that the projected detection pattern is included in the measurement target area of the imaging optical system of the optical measuring means over a wide range from near to far. However, light attenuates due to diffusion as it propagates, and the larger the projection angle, the greater the attenuation rate.
Conventional distance measuring devices, in which the auxiliary light source, transparent film, projection lens, etc. that make up the auxiliary light projection device are installed in a fixed position, can detect various objects located in a wide range.
In order to project the detection pattern at a brightness that provides the necessary contrast, the emission brightness of the auxiliary light source must be increased, and for cameras etc. that are powered by batteries, increased power consumption is a problem with the battery life. This is undesirable because it accelerates wear and tear.

On the other hand, the detection pattern can be projected at a brightness that provides the necessary contrast to objects located far away.
It is also possible to narrow down the light from the auxiliary light source and emit it, but in this case, the projection angle will inevitably become smaller, so when the detection pattern is projected, the light beam from the detection pattern can be measured by optical measurement. The objects included in the measurement target area of the imaging optical system of the means, that is, the objects whose distances can be measured by the optical measuring means are only those located within a limited range. Therefore, in order to make it possible to measure distances to various objects in a wide range from near to far, it is necessary to provide multiple auxiliary light projection devices, one for short distances and one for long distances. This may lead to an increase in the number of points and costs.

In view of the above-mentioned circumstances, it is an object of the present invention to project a detection pattern during low brightness and perform distance measurement using the detection pattern as an aid, without increasing power consumption. An object of the present invention is to provide a distance measuring device capable of measuring the distance to an object.

[Means to solve the problem]

The characteristic configuration of the distance measuring device according to the present invention is that a group of light receiving elements arranged in a row are arranged in parallel in order to form an image of the object through an imaging optical system and measure the distance to the object. changing the emission position or the emission direction of an auxiliary light projection device for projecting a detection pattern for distance measurement assistance, in which bright areas and dark areas are arranged alternately along the target object, with respect to the optical axis of the imaging optical system; A position detection light projection device for projecting a position detection pattern in which bright areas and dark areas are lined up along the change direction is provided, and a position detection light projection device for projecting a position detection pattern in which bright areas and dark areas are lined up along the change direction is provided, and a position detection light projection device is provided at The light beam from the detection pattern is provided in a state in which the emission position or the emission direction is changed in conjunction with the change, and the light beam from the detection pattern is received in the measurement target area of the optical measurement means by receiving the light beam from the position detection pattern. The reason is that a light receiving means is provided for determining whether or not the object is included.

[For production]

That is, by changing the emission position or the emission direction of the auxiliary light projection device by the projection changing means with respect to the optical axis of the imaging optical system of the optical measurement device, the distance between the optical measurement device and the auxiliary light projection device can be changed. Despite the parallax, the position where the projected light beam of the detection pattern intersects with the distance measurement light beam incident on the optical measuring means can be changed along the distance direction with respect to the distance measuring device. Therefore, even if the projection angle of the detection pattern is small, the projection angle of the projected detection pattern can be It becomes possible to project the detection pattern in a state where the light beam is included in the measurement target area of the optical measurement means.

Moreover, in conjunction with changing the emission position or emission direction of the auxiliary light projection device, the emission position or emission direction of the position detection light projection device is changed, and the position detection pattern is projected onto the target object together with the detection pattern for distance measurement. The light receiving means receives a beam of light from the position detection pattern, and it can be determined whether or not the distance measurement detection pattern is included in the measurement target area of the optical measurement means. It is possible to easily determine whether or not distance measurement for assistance is possible.

In addition, the position detection pattern has bright areas and dark areas lined up along the direction in which the projection changing means changes the emission position or the emission direction of the auxiliary light projection device, and the light receiving means can detect the bright areas and the dark areas. By detecting the contrast formed by the above changes, it is possible to reliably detect the position of the position detection pattern due to the change, thereby determining the positional relationship between the measurement target area of the optical measurement means and the detection pattern. Since reliable grasping is possible, it is possible to reliably determine whether or not the above-described distance measurement is possible.

Note that among the changes in the emission position or the emission direction of the auxiliary light projection device by the projection changing means, the emission position can be changed by, for example, a method of sliding the entire auxiliary light projection device, and the emission direction can be changed by: For example, this can be done by fixing one end of the auxiliary light projection device and swinging the other end. In addition, the position detection light projection device can be used, for example, by using the same light source as the fill light projection device and by attaching a striped pattern corresponding to the position detection pattern together with a striped pattern corresponding to the detection pattern. The structure may be used in common, or it may be provided independently from the auxiliary light projection device. Furthermore, the light receiving means may constitute a part of the optical measuring means, or may be independent from the optical measuring means. As mentioned above, it is more useful if the position detection light projection device and the light receiving means are also used as the auxiliary light projection device and the optical measurement means, since it is possible to reduce the number of parts and simplify the configuration. .

〔Example〕

Hereinafter, the present invention will be described in detail based on the drawings.

FIG. 2 is a schematic diagram of the entire camera including a focus detection device (X) which is an example of a distance measuring device according to the present invention. This camera consists of a camera body (1), a photographic lens (2) detachably attached to the camera body (1), and a flash detachably attached to a hot lens (lb) of the camera body (1). It consists of a device (3).

The main part of the focus detection device (X) according to the present invention is provided inside the camera body (1), and as will be described in detail later, the focus detection device (X) is The photographic lens (2)
The camera is configured to perform a focus detection operation to determine the deviation of the movable lens section from the in-focus position of the subject. Furthermore, a focus adjustment device is provided inside the camera body (1) to move the movable lens portion of the photographic lens (2) to a focus position for the subject based on the detection deviation determined by the focus detection device. It is being

The focus detection device (X) is configured using a phase difference detection method, and as is already known, for highly accurate focus detection, the subject image for focus detection must have a certain degree of contrast. It needs to be something. Therefore, in order to be able to perform highly accurate focus detection even for subjects where the subject image for focus detection obtained has low contrast, such as subjects in dark places, we It is provided with an auxiliary light projection means (4) for projecting an auxiliary light beam for projecting.

The auxiliary light projection means (4) includes the flash device (3).
) A first auxiliary light projection device (4A) provided on the camera body (1) and a second auxiliary light projection device (4B) provided on the camera body (1)
It is composed of. Both of these auxiliary light projection devices (4A
), (4B) are independent auxiliary light sources (11
), (16) and projection lenses (12), (17). The first auxiliary light projection device (4A) is
A second auxiliary light projection device (4B) is configured to project a first auxiliary light beam onto an incident light beam region by a focus detection optical system (AO), which will be described later, forming the focus detection device (X).
is to narrow down an auxiliary ray bundle equivalent to the first auxiliary ray bundle and project the second auxiliary ray bundle onto an area narrower than the projection area of the first auxiliary ray bundle by the first auxiliary light projection device (4A). Each of them is configured as follows. The specific configurations of the two auxiliary light projection devices (4A) and (4B) will be detailed later.

The projection areas of the two auxiliary light beams will be further explained.

As shown in FIG. 1, the first auxiliary light beam (shear) from the first auxiliary light projection device (4A) is projected onto a relatively wide area. The projection area of this first auxiliary ray bundle (shea) is
The focus detection device (X
) by the focus detection optical system (AO)
f).

Therefore, in the entire range that can be photographed by the photographing lens (2) in the direction along the photographing optical axis (Op), the first auxiliary light beam (La) is projected on the subject to assist in focus detection. A focus detection device (
X) can stare at you.

- Also, the second auxiliary light beam (Lb) from the second auxiliary light projection device (4B) is narrowed down and projected onto a narrower area than the first auxiliary light beam (La), as shown in the figure (Ab ) wraps around the incident ray flux region f). Therefore, the second auxiliary ray bundle (Lb), which is stronger than the first auxiliary ray bundle (La), appears on the subject within this range (Ab).
), the focus detection device ff(X) can form an image with a strong contrast by glaring at the image. Accurate focus detection can be performed even when the contrast of the image formed by the projection of La) is low.

In FIG. 1, (5) is a main mirror that divides the light beam from the subject into the film (F) side and the finder optical system (6) side, and (7) is the main mirror (5). )
This is an auxiliary mirror that guides a beam of light passing through the film (F) toward the film (F) to the focus detection device (X).

Next, using FIG. 3, the focus detection optical system (AO)
The surrounding configuration will be explained.

In Fig. 3, (TL,) and (TL2) are lenses that constitute the photographing lens (2), and both of these lenses (TL,
,).

(TL2) are distances (PZI)', (PZ2), (P
z, <Pz2) (hereinafter, this distance will be referred to as the exit pupil distance). A field mask (FM) is disposed near the predetermined imaging plane (FP).

This field mask (FM) has a horizontally long first
A rectangular opening (BO) is provided, and a pair of vertically elongated second rectangular openings (Eat) and third rectangular openings (BO2) are provided on both sides.
) is provided. The light beams from the subject that have passed through the rectangular openings (Eo), (Eat), and (BO2) of the field mask (FM) are separated by separate condenser lenses (Lo
), (Lo,), (Lo,) (hereinafter, rectangular opening (Eo), (Eat), (ε
02), the first condenser lens (LoL second
Condenser lens (Log), 3rd condenser lens (
It is called Lo2). ), respectively, and are focused.

The above-mentioned condenser lens (Lo), (LO=),
Behind (102), an aperture mask (AM) and a re-imaging lens plate (L) are arranged. The reimaging lens plate (
L) is a re-imaging lens pair (
Ll), (L2), and a pair of re-imaging lenses (L3), (L4) arranged vertically on both sides, respectively.
The re-imaging lenses (L, ) to (L8) are all plano-convex lenses with the same radius of curvature. (Hereinafter, the field mask ( FM) rectangular opening (Bo), (II:o+),
(Bo, ), the central reimaging lens pair (Ll)
, (L2) as a first re-imaging lens pair, and both re-imaging lens pairs (L3).

(L4), (LS), and L) are respectively referred to as a second re-imaging lens pair and a third re-imaging lens pair. ) Also, the aperture mask (AM) includes each re-imaging lens (Ll).
At the position corresponding to ~(L6), the aperture opening (A1) ~(
A6) is provided. This aperture mask (AM) is disposed just in front of the re-imaging lens plate (L), and is in close contact with the flat portion of the re-imaging lens plate (L).

Further behind the re-imaging lens plate (L), three CCD line sensors (Pa
), (POI), and (PO2). The central CCD line sensor (PO) is arranged horizontally in the center of the substrate (P), and the CCD line sensors (Pot) on both sides.

(Pa□) are arranged vertically on both sides of the substrate (P), and the direction of installation of each re-imaging lens pair on the re-imaging lens plate (L) and each CCD line sensor (Pa) ,
They are arranged so that the installation directions of (PO,) and (PO2) are the same. Above CCD line sensor (Pa)
, (Pot), and (PO2) are respectively the first. Second
It has two light-receiving element rows, and is configured to separately photoelectrically convert two subject images for focus detection that are re-imaged on the CCD line sensor by the re-imaging lens pair. (Hereinafter, each of the above CCD line sensors (Po)
, (POI), (PO2) as the field mask (FM)
Rectangular opening (EO), (Eat).

(BO2), the first CCD line sensor (Po
), the 20th CD line sensor (Pot), and the 3rd CCD line sensor (Po□). ) The blocks (AFMO) surrounded by dotted lines in the figure are assembled together to form an AF (autofocus) sensor module. and field mask (FM)
-: Lens lens (Lo), (Lo+).

(LO2)・Aperture mask (AM)・Reimaging lens plate (L
) constitutes a focus detection optical system (AO).

A photographic lens (2) and a focus detection optical system (A) configured as described above.
The focus detection device (X) is configured to detect the focal position in the following manner using the object image obtained by the imaging optical system consisting of O).

The off-axis distance measuring light ray east from the subject in the area outside the optical axis (Op) of the photographing lens (2), including the principal rays (β, ) and (β4), is set at a predetermined position with respect to the optical axis (Op). Optical axis (Op
), the light enters the field mask (F 1,1'), passes through its second rectangular opening (tEo, ), and enters the second condenser lens (Log).

This off-axis survey path light beam is transmitted through the second condenser lens (L
ot) toward the optical axis (Op), and is focused by the second aperture aperture (A3) of the aperture mask (AM).
), (A4) and enters the second re-imaging lens pair (LS), (L,) of the re-imaging lens plate (xi).

The off-axis distance measuring light beam east incident on the second re-imaging lens pair (LS), (Ll) is
LS), (Ll) onto the second CCD line sensor (Pa,), and a pair of subject images for focus detection are re-imaged in the vertical direction on this second CCD line sensor (Par).

Similarly, the off-axis ranging ray east including the principal ray (I!, (ff16)) enters the field mask (PM) so as to leave the optical axis (Op) at the above-described predetermined angle. Third rectangular opening (BO2), third condenser lens (Loz)
, the third aperture aperture (AS) of the aperture mask (AM).

(A6) and the third re-imaging lens pair (LS), (LS
), and is focused on the third CCD line sensor (PO2), and a pair of subject images for focus detection are re-imaged in the vertical direction on this third CCD line sensor (PO2).

On the other hand, the photographic lens (
The off-axis optical path ray flux from the subject in the area including the optical axis mark p) in 2) is transmitted through the first rectangular opening (Eo) on the optical axis (Op) of the field mask (FM), the first Condenser lens (L
o) The first aperture aperture (AI), (A2) on the optical axis (Op) of the aperture mask (AM), and the first re-imaging lens pair (Ll), (L2), to the first CCD. The light is focused on the line sensor (PO), and a pair of subject images for focus detection are re-imaged in the left and right direction on this first CCD line sensor (PO).

And the above CCD line sensor (Po), (Pop
).

The focal position of the photographing lens (2) with respect to the subject is detected by determining the positions of the subject images for focus detection that form the three pairs of re-imaged pairs formed on (Pa□).

To explain the correspondence with the viewfinder field diagram shown in Fig. 4, the first CCD line sensor (PO) is located in the on-axis focus detection area (ISI), and the second CCD line sensor (Po,
The third CCD is located in the off-axis focus detection area (IS2) on the left side.
The line sensor (Po2) corresponds to the off-axis focus detection area (IS3) on the right side. There are three focus detection areas (ISI) shown by solid lines in the center of the photographic screen (S).

(IS2), (153) (Hereinafter, when it is necessary to distinguish between them, the first island (ISI)
, 2nd island (IS2), 3rd island (153
) is configured so that focus detection can be performed on a subject located at Note that in the figure, a rectangular frame (AF) indicated by a dotted line is displayed to show the photographer the photographing area where focus detection is being performed.

Next, the specific configurations of the first auxiliary light projection device (4A) and the second auxiliary light projection device (4B) described above will be explained.

As shown in FIGS. 5 and 6, the first auxiliary light projection device (4A) is an LED unit (11) that is an auxiliary light source.
, a projection lens (12), a projection pattern film (13) located between them, and the like.

The LED unit (11) includes three LED bellets.
(14a) to (14c) are arranged horizontally in parallel in an optical resin (for example, acrylic, epoxy, etc.) (15), and they are placed on the output side of the optical resin (15). 3 LED pellets (14a) to (14
Corresponding to c), each separate ball lens part (15a) to (15
c).

In addition, as shown in FIG.
) to (1, 4c), each different projection pattern (1
3a) to (13c) are formed. Those three projection patterns (13a) to (13c) are the central one (1
3a) is the one with random vertical stripes, and the one on both sides (1
3b) and (13c) each have random horizontal stripes. And the three LED pellets) (
The three projection patterns (13a) on this projection pattern film (13) are created by the light emission of 14a) to (14c).
The images of (13c) to (13c) are configured to be projected onto the subject as a detection pattern for distance measurement assistance, as shown in FIGS. 7(a) and (b).

First, using FIG. 1, this first auxiliary light projection device (4A
), the projection area of the first auxiliary light beam (La) from the focus detection optical system (A
Although it has been explained that the incident light flux range is O), in addition, as in the case where the focal length [fl] of the photographing lens (2) changes, the projection area of the focus detection area that is the measurement target area The projection area of the first auxiliary ray bundle (La) in plan view is configured to include the focus detection area even when the angle changes in the horizontal direction.

This is shown in FIGS. 7(a) and 7(b).

Figure 7 (li is the focal length of the photographing lens (2) [fl
is [50mm], Fig. 7(0)C, photographing lens (
The case where the focal length [fl of 2) is [28 mm1] is shown. In either case, the focus detection area of the focus detection optical system (AO) in this embodiment, which is a collection of the third focus detection areas (ISI) to (IS3) described above, is the first auxiliary light beam. It can be seen that it is included in the projection area of the bundle (La).

Furthermore, regardless of the type of photographic lens (2), etc., the central first island (ISI) is always centered on the central projection pattern (ISI).
3a) The second island (IS2) and the third island (IS3) on both the left and right sides wrap around the image of
) are always left and right projection patterns (13b), respectively.
It is configured to wrap around the statue of (13c),
In any of the focus detection areas (ISI) to (IS3), it has become possible to use striped images aligned along the longitudinal direction of the area as images with contrast to assist focus detection. There is.

In addition, as shown in FIG. 6, the projection pattern film (13) becomes more distant from the projection optical axis ([]S+) of the first auxiliary light projection device (4A), the further the projection pattern film (13) becomes
LED pellets (14a) arranged in parallel in a direction perpendicular to
The projection pattern (13b or 13C), which is provided in a curved posture and located far from the projection optical axis (OS+), is a projection lens consisting of a single lens. (12) is configured to prevent a blurred image from being projected onto the subject due to the aberration.

On the other hand, the second auxiliary light projection device (4B), which is the auxiliary light projection device according to the present invention, is composed of an LED beret (16), a light projection lens (17), etc., as shown in FIG. In this second auxiliary light projection device (4B), a projection pattern (16b) is directly attached to the light emitting portion (16a) of the LED pellet (16).

The projection pattern (16b) is the result of random vertical stripes, and the light emitting part (16a) of the LED pellet (16)
Due to the light emission, the image of this projection pattern (16b) becomes
As shown in FIG. 9, in the range (Ail) where the second auxiliary light beam (Lb) wraps around the projection area (Lf) of the focus detection area, as shown in FIG.
ISI) to (IS3), the first island in the center (
ISl) and is configured to be projected onto the subject.

As shown in FIG.
On the upper surface of the layer (16c), an opaque electrode (18) for passing a current through the LED pellet (16) for light emission and an opaque metal layer (19) are deposited in the arrangement shown in FIG. This creates a vertical striped pattern as a whole. The electrode (18) is LE as shown in FIG.
When viewed from the front of the D pellet (16), they are provided at four locations on the top, bottom, left and right, and among these electrodes (18), those arranged in the vertical direction are 1B&, 18c), (18)
The metal layer (19) is formed between each electrode (18) and the upper and lower frames.

As shown in FIG. 11, the substrate (20) of the LED pellet (16) includes a common electrode (21c) that is shared by the four electrodes (18), and a common electrode (21c) that is shared by the four electrodes (18).
), separate electrodes (21a), (21b) for the upper electrodes (18a), (18b), and a common electrode (21d) for the lower two electrodes (18c), (18d). ) and each of these electrodes (
21a), each separate terminal (22a) for (21b)
- (22d) extend from the substrate (20).

And the electrode (21a) of the substrate (20), (21
d) to each electrode (18a) of the LED bellet (16).
) to (18d) by controlling the applied voltage to
The structure is such that the intensity of light emitted from the LED pellet (16) can be varied in the vertical direction.

In other words, as shown in FIG.
6) for applying voltage (18a), (18c
) or (18b), (18d) (Hereinafter, only the electrodes (18a) and (18c) on one side will be explained) are provided at a distance, so there is less risk of mutual interference, and these electrodes (18a), The current flowing from (18c) into the LED pellet (16) is connected to the electrodes (18a>,
(18c) can be varied depending on the applied voltage, thereby making it possible to partially vary the emission intensity. Specifically, the LED bellet (1
6) (7) When viewed from the front, the upper electrode (18a),
(18b) is applied to the lower electrode (18c).
), (18d),
As shown in FIG. 12, the emission intensity of the LED pellet (16) is set to be greater in the upper part than in the lower part.

To explain this in relation to the fact that the light emitted from the LED pole left (16) is used as the second auxiliary light beam (Lb) for assisting focus detection, as shown in FIG.
There is a variation between the photographing optical axis (Op) and the projection optical axis (032) of the second auxiliary light projection device (4B), so that the upper side of the projection pattern (16b) is not visible to distant subjects. ) is projected onto the subject near the camera.
Since the image of the lower part of the projection pattern (16b) is projected, the second auxiliary ray bundle (Lb) is set such that the intensity of the upper part is greater than the intensity of the lower part. , while allowing the image of the projection pattern (16b) to be clearly projected onto a distant object, while eliminating the use of unnecessarily strong light when projecting the image of the projection pattern (16b) onto a nearby object. This is to reduce power consumption.

Furthermore, this second auxiliary light projection device (4B) is for projecting a second auxiliary light beam (Lb) for assisting focus detection onto a low-contrast subject especially under high brightness. As described in , in order to project light with a higher intensity than the first auxiliary ray bundle (La) without increasing power consumption, the projection area is the first auxiliary ray bundle (La).
Even within the range that can be photographed by the photographing lens (2), the image of the projection pattern (16b) projected onto the subject is smaller than the projection area of the three focus detection areas (ISI) to (La). IS3) may not overlap, so in order to project the second auxiliary ray bundle b) to the subject in such a range and enable the same focus detection operation, the second auxiliary light projection The projection direction of the second auxiliary light beam (Lb) from the device (4B) can be changed vertically or horizontally. Next, the configuration for this purpose will be explained.

As shown in FIG. 13, the second auxiliary light projection device (4B) includes a base plate (23) fixed to the camera body (not shown).
) is held in a holder (24).

The light projecting lens (17) is fitted and glued into the holder (24), and the LED bellet (16) is attached to the LED holder (25) attached to the holder (24).
) is maintained. This LED holder (25) has a pair of mounting screws (26a).

(26b) of the fixed plate (27) fixed to the top surface of the holder (24), and the protrusion (24a) integrally connected to the holder (24).The back surface of the gutter holder (24). (24c) and the projection optical axis (O
s2) direction, and as shown in FIG.
The head (28a) rotatably fits into the through hole (27a) formed in the fixed plate (27), and the holder (24)
) The adjusting screw (28) whose tip end portion (28b) rotatably fits into the through hole (24b) formed in the female threaded portion (25a)
) is configured to be positioned in the vertical direction by screwing into the screws.

Using the above configuration, the LED bellet (25) and the LED holder (25) can be adjusted by rotating the adjustment screw (28).
16) in the vertical direction to create the second auxiliary ray bundle (L
The projection direction of b) can be changed to the vertical direction. That is, as shown in FIG. 14, the female threaded portion (
As mentioned above, the LED holder (25) to which 25a) is screwed is positioned in the direction of the emitted light 'h (Os2), so by rotating this adjustment screw (28), the LED holder (25) The screw is fed and the position is changed in the vertical direction.

Further, the holder (24) has a tip end connected to the base plate (23).
It is attached to the base plate (23) by a reference screw (29) and an eccentric screw (30) which are caulked. Using this configuration, by rotating the eccentric screw (30), the By pressing the inner wall of the through hole (24a) of the holder (24) into which the head (30a) of the eccentric screw (30) fits, the LED pellet (16) is removed together with the holder (24).
The projection direction of the second auxiliary beam bundle b) can be changed in the left-right direction by rotating around the reference screw (29).

The head (28a) of the adjustment screw (28) and the head (30a) of the eccentric screw (30) are extended upwardly and protruded from the top surface of the camera body (1),
The projection direction of the second auxiliary light beam (Lb) described above can be changed manually.

Furthermore, the outer peripheral surfaces of the portions of both screws (28) and (30) that protrude from the camera body (1) are knurled for use as handholds. That is, the above-described configuration constitutes a projection changing means.

Further, as the projection direction of the second auxiliary light beam (Lb) is changed, the image of the projection pattern (16b) projected onto the subject is adjusted to the three focus detection areas (ISI).
, (IS2), (IS3), that is, whether or not focus detection is possible can be detected as follows.

As shown in FIG. 9, for horizontal adjustment, focus detection is possible by detecting contrast that changes in the horizontal direction due to the projection pattern (16b) of vertical stripes on the first island (ISI). Something is starting to be detected. Regarding adjustment in the vertical direction, the projection pattern (16b) is provided with a vertical striped dummy pattern (16X) made of a metal layer that provides a contrast that changes in the vertical direction at both the upper and lower ends, and a second island (16X) is attached to the projection pattern (16b). In IS2), it is detected that focus detection is possible by detecting contrast that changes in the vertical direction of the dummy pattern (16X) which is a position detection pattern. That is, in this embodiment, the second auxiliary light projection device (4B) also serves as the position detection light projection device, and the light receiving element group constituting the optical measurement means also serves as the light receiving means.

Next, the operation of the camera equipped with the focus detection device (X) configured as above will be explained. First, the outline of the control circuit of this camera will be explained using FIG. 15.

The left side is the block on the camera body (1) side, (100)
is a CPU that controls the operation of the entire camera.

(101) is a focus detection block that photoelectrically converts the image obtained by the focus detection optical system (AO) and outputs it to CPU (100), and CPU (100) is a focus detection block ( 101) is used to calculate the deviation from the in-focus position of the photographing lens (2) with respect to the subject. That is, the CPU (100) constitutes focus detection means. The focus detection optical system (AO) described above and the focus detection means constitute an optical measuring means that measures the distance to the object using the contrast of the object image. .

The focus detection block (101) includes a CPU (10
The above-mentioned operation is performed in response to a control signal for focus detection operation from 0), and the brightness information of the subject obtained by monitoring the output of the CCD line sensor (Po) is
Output to U (100).

That is, the focus detection block (101) serves as subject brightness detection means. (10, 2) is based on the focus detection result using the output signal from the focus detection block (101). In response to the control symbol from the CPU (100), the photographic lens (2) is focused on the subject. This is a motor drive circuit that drives and controls a focus adjustment motor (hereinafter abbreviated as AF motor) (103) to move it to a focus position.

(104) is an encoder that outputs a pulse signal corresponding to the movement of the photographing lens (2) to the CPU (100);
P U (100) receives the output pulse from this encoder (104) and recognizes the position of the photographic lens (2).

(S+) is a distance measurement switch that is closed by pressing the release button (1a), and this distance measurement switch (S,)
When the focus detection block (101) is closed, the CPU (100) outputs a control signal for starting a focus detection operation to the focus detection block (101).

(200) is the lens RO installed in the photographic lens (2)
M stores lens information such as the focal length and aperture F value of the photographic lens (2). And this lens ROM
(200) receives a control signal from CPU (100) and transfers the stored lens information to CPU (100).
0). CPU (100) and this lens R
The OM (200) is connected to a contact group attached to a lens board (not shown) on which the photographic lens (2) is attached by contacting a contact group of the photographic lens (2).

(105) is the second auxiliary light projection device (4B) described earlier.
) is one LED pellet (16), and is drawn corresponding to three light emitting parts on both sides of the upper part and the lower part when viewed from the front. This LED pellet (16) is C
Light emission and stopping of light emission are controlled by an LED drive circuit (106) that receives a control signal from P U (100).

(107) is a power supply battery that is detachably attached to the camera body (1), and is used to power the CPU (100), the focus detection block (101), and the motor drive circuit (1) mentioned above.
02)・LED bellet (16)・LED drive circuit (1
7) is supplied with power from this power source battery (107).

(SX) is a focal brain shutter (not shown)
The opening/closing signal is transmitted to the flash device (3) at the X contact which is closed when the front curtain travels.

The right side of the figure is the block on the flash device (3) side;
01) is the light emitting part, (302) is the light emitting capacitor (30
3) is a booster circuit that boosts the charging voltage.

(304) is the first auxiliary light projection device (4A) described earlier.
) is a group of three LED pellets, and the LED drive circuit (
305) controls the light emission and stop of light emission.

(306) is a power supply battery that is detachably attached to the flash device (3), and (307) is a power supply battery that stabilizes the output of the power supply battery (306), whose output fluctuates due to flash charging, and projects the first auxiliary light. This is a stabilized power supply for applying power to the three LED pellet groups (304) and the LED drive circuit (305) of the device (4A).

Between the camera body (1) and the flash device (3), a CPU (100) transmits the status signal of the flash device (3).
a first signal line (SLI) for transmitting to the CP
Control signal from U (100) to flash device (3)
a second signal line (SL2) for transmitting the opening/closing signal of the X contact (SX) to the LED drive circuit (305), and a third signal line for transmitting the opening/closing signal of the X contact (SX) to the light emitting part (301) of the flash device (3). (SL3) is provided. And those three signal lines (SLI) ~ (SL
3), when the flash device (3) is attached to the hot shoe (1b) of the camera body (1), the contact groups (111) to (113) attached to the hot shoe (1b) are
Contact group (31) attached to the foot of the flash device (3)
1) to (313), they are connected to each other.

As shown in FIG. 16, the LED drive circuit (106) of the camera body (1) and the LED drive circuit (305) of the flash device (3) are connected to a monitor operational amplifier ( The LED drive circuit (106) of the camera body (1) is divided into three LED pellets (16) by being turned on and off by the output signal from this operational amplifier (OP). and the LED drive circuit of the flash device (3).
305), separate switching transistors (Tri) to (Tr3) are provided to control the light emission of each of the three LED pellets. and,
Separate resistors (R1) to (R3) are connected to the emitter terminals of these three transistors (Tri) to (Tr3), and the resistance values of these three resistors (R1) to (R3) The transistor (Tr
It is configured such that the light emission patterns can be made different by changing the current values in the active state of i) to (Tr3).

The CPU (100) detects, based on a detection signal from a focus detection block (101) which is a subject brightness detection means, when the subject image for focus detection lacks contrast and sufficient reliability cannot be obtained. Specifically, when the brightness of the subject is lower than the first set brightness, the APEX value [BV
<4], the auxiliary light projection device (4) is activated. That is, the CPU (100) constitutes an auxiliary light projection control means. Furthermore, CPU (100) is
If the brightness of the subject is lower than the first set brightness and higher than the second set brightness, specifically, the APEX value is [-1≦
When Bv<4], it is determined that the object has high brightness but no contrast, and the second auxiliary light projection device (4B) is activated, while the brightness of the object is lower than the second one.
In other words, when the APIEX value is lower than the set brightness of [B
v <-1], it is determined that the subject is of low brightness, and a control signal is transmitted to the flash device (3) to operate the first auxiliary light projection device (4A). That is, the CPU (100) serves as an operating means for selectively operating the first auxiliary light projection device (4A) and the second auxiliary light projection device (4B).

Note that CPU (100) is the camera body (1).
If the flash device (3) is not attached to the
The second auxiliary light projection device (4B) is always activated when the brightness of the subject is lower than the first set brightness. In addition, when the brightness of the subject is higher than the first setting brightness, that is, when the AP8X value is [By≧4], it is determined that focus detection is impossible no matter which auxiliary light beam is used, and the flash device is Regardless of the presence or absence of (3), neither of the auxiliary light projection devices (4A or 4B) is activated. Table 1 below summarizes the operating states of the two auxiliary light projection devices (4A) and (4B). In the table, [○] mark indicates operation, and [X] mark indicates non-operation.

Next, the operation of the automatic focus adjustment device among the operations of this camera will be explained using the flowchart of FIG. 17.

This flow starts when the distance measuring switch (Sl) mentioned above is closed. When this flow starts, first initialize all memories and flags.
1>, after inputting lens data from the lens ROM (200), R2>, a control signal is output to the focus detection block (101) to start charge accumulation in the CCD (R3).

After waiting until charge accumulation is completed <R4>, focus detection data is received from the focus detection block (101) <R5>. Next, the LE of the second auxiliary light projection device (4B)
A control signal is output to the D drive circuit (106) and the LED drive circuit (305) of the first auxiliary light projection device (4A).

Stop the light emission of (4B) <tt6. R7>. Then, based on the input signal from the encoder (104), it is determined whether the photographing lens (2) is at the end position, either the closest position or the infinity position (R8).

If it is determined that the photographic lens (2) is at the end position, a control signal is output to the lens drive circuit (102) to stop driving the photographic lens (2), and then the photographic lens (2) is stopped.
2) is at the closest position <910>.

As will be described later, focus detection is possible when the subject image for focus detection has no contrast and the focus detection calculation is unreliable, and the luminance of the subject is equal to or higher than the first predetermined luminance [By<4]. In order to search for objects with contrast, the photographing lens (2) is moved back and forth within its movable range (hereinafter, this operation is referred to as low contrast scanning). In step <$10>, remove the photographic lens (2
) is determined to be not at the closest position, the photographing lens (2) is at the infinity position, indicating that a contrasting subject could not be found even after this low-contrast scan was completed. A message indicating that the focus detection operation is not possible is displayed <#100>, and this flow is ended.

On the other hand, take a photo with a step of <$100>: (2)
is determined to be at the closest position, low contrast scanning is in progress, and the lens drive circuit (102
) to start driving the photographing lens (2) toward the infinite position, proceed to step <1tll> and (312>.Furthermore, in step <f18), the photographing lens (2) is Even if it is determined that it is not at the end position, <#
It will jump to step 12>.

In steps <#12> to <#14>,
Using the focus detection data input from the focus detection block (101) in step <#5>, the focus position of the photographic lens (2) for the subject is determined for each island (ISI) to (IS3). The deviation, that is, the amount of defocus is calculated. Next, it is determined from the degree of correlation of the calculation result whether it is reliable, that is, whether the light beam from the subject has the contrast necessary for focus detection <#15>.

If it is determined that it is unreliable, then the photographic lens (2)
It is determined whether or not it is being driven <#20>.

If it is determined that the photographic lens (2) is being driven, <#
Return to step 3> and repeat the above-mentioned operation. If it is determined that the photographic lens (2) is not being driven, then
Using the brightness information of the subject input from the focus detection block (101) in step <#5>, determine in which brightness range the brightness of the subject falls <#21, 4:22
>.

If it is determined that the brightness of the subject is equal to or higher than the first set brightness [Bv≧4], a control signal is output to the lens drive circuit (102) to perform a low contrast scan, and the photographic lens (2) is After starting driving to the closest position, the process returns to step <#3D, <#3> and the above-described operation is repeated.

If it is determined that the brightness of the subject is less than the second set brightness [av<-1], it is determined whether the flash device (2) is attached <#23>. Flash device (2
) is not attached, the process advances to step <#25>. On the other hand, if it is determined that the flash device (2) is attached, then the second flash device passes through this loop.
It is determined whether or not it is the third time <824>. If it is determined that passing through this loop is the first time, a control signal is output to the LED drive circuit (305) of the first auxiliary light projection device (4A) to project the first auxiliary light beam. <:1I32>
, return to step <#3> and repeat the above-mentioned operation.

Also, in step <824>, 2 passes through this loop.
If it is determined that it is the second time, it means that the focus detection result is determined to be unreliable even by the projection of the first auxiliary light beam by executing step <#32> described above, and the focus detection result is determined to be unreliable. To perform a contrast scan, <#3
Proceed to step 1>.

If it is determined that the brightness of the subject is less than the first set brightness and higher than the second set brightness [-1≦Bv<4], then it is determined whether this is the second time to go through this loop. is determined <825>. If the brightness of the subject described above is less than the second set brightness [Bv<-11 and the flash device (2) is not attached, the process also proceeds to step <#25>. If it is determined in step <325> that this is the first time passing through this loop, the second auxiliary light projection device (
After outputting a control signal to the LED drive circuit (106) of 4B) to project the second auxiliary light beam, <1t33), <#
Return to step 3> and repeat the above-mentioned operation.

Also, 2 passes through this loop in step <825>.
If it is determined that it is the second time, it indicates that the focus detection result is determined to be unreliable even by the projection of the second auxiliary light beam by executing the step <#33> described above, and the focus detection result is determined to be unreliable. To perform a contrast scan, <#3
Proceed to step 1>.

On the other hand, if it is determined in step <#15> that it is reliable, select which of the defocus amounts calculated in steps #12 to <[4>] should be used to adjust the focus. #51>, it is determined whether the defocus amount is less than a predetermined value, that is, whether the photographing lens (2) is within the focusing range <#52>.

If it is determined that the photographing lens (2) is not within the focusing range,
Calculating the lens drive amount from the defocus amount <:1
t53). In addition, in this calculation, the photographing lens (2)
If it is being driven, the amount of movement is corrected.

After that, a control signal is output to the lens drive circuit (102) to set the number of drive pulses for the AF motor (103) <#54>, and to start driving the photographing lens (2).Jt55), encoder (104) ) After waiting until the number of input pulses from ) matches the number of driving pulses, <
t56>, output a control signal to the lens drive circuit (102) to stop driving the photographing lens (2) #57>,
After that, proceed to step <$58>. On the other hand, (#52
If it is determined in step > that the photographing lens (2) is within the focusing range, the process also jumps to step <#58>. (In step #58, a message indicating that the camera is in focus is displayed, and then this flow is ended and the process returns to the main routine.

[Another example]

Next, another example of the present invention will be listed.

1> In the previous embodiment, the flash device (3) is provided with the first auxiliary light projection device (4A), and the camera body (
1) in which the second auxiliary light projection device (4B) is provided, but instead, the first auxiliary light projection device (4A) is provided in the camera body (1) and the second auxiliary light projection device (4B) is provided in the camera body (1). 4B) may be provided in the flash device (3), or both of the auxiliary light and projection devices (4A) and (4B) may be provided together in either the camera body (1) or the flash device (3). In that case, instead of configuring both the auxiliary light projection devices (4A) and (4B) as completely independent structures as in the previous embodiment, the auxiliary light projection device (4) may have an auxiliary light source and a fixed lens. A movable lens, etc. that can move in and out of the optical path is provided, and the first
While it functions as an auxiliary light projection device (4A), it functions as a second auxiliary light projection device (4A) with the movable lens positioned within the optical path.
B), or as an auxiliary light projection device (4), an auxiliary light source and a light projecting lens that moves along the projection optical axis are provided, and the first auxiliary light is set according to the position of the light projecting lens. It may be configured to be able to switch between a state in which it functions as a projection device (4A) and a state in which it functions as a second auxiliary light projection device (4B).
), (4B) A part of the configuration may be shared between them.

2> In the previous embodiment, the area of the projection area of the second auxiliary light beam (Lb) from the second auxiliary light projection device (4B) is constant and the intensity per unit area is fixed. However, instead of that, the light projection lens (17) is moved to the light projection optical axis (08
2) Change the amount of narrowing down of the second auxiliary ray bundle (Lb) by moving the second auxiliary ray bundle (Lb) along It may be configured so that it can be changed steplessly or continuously in a plurality of steps.

3) In the previous embodiment, the CPU (100) as the operating means controls both the auxiliary light projection devices (
4A) and (4B), but instead, both of these auxiliary light projection devices (4A)
, (4B>) may be provided as a manually operated changeover switch or the like.

4) In the previous embodiment, corresponding to the plurality of focus detection areas (ISI) to (153) by the focus detection device (X), each focus detection area is detected by the first auxiliary light projection device (4A). The configuration was such that images with different contrasts could be projected to the areas (ISI) to (IS3), but instead, the first auxiliary light projection device (4A) projected all the focus detection areas (131) to (IS3) may be configured so that an image with the same contrast can be projected. In that case,
For example, the focus detection device (ISI) to (IS3) may be shaped in the same direction.
X) changes are possible. Furthermore, the focus detection device (X) may be configured to perform a focus detection operation using a beam of light from a subject located in a single focus detection area.

<5> In the previous embodiment, the projection direction of the second auxiliary light beam (Lb) can be changed vertically and horizontally by manually changing the attitude of the second auxiliary light projection device (4B). However, instead of that, the projection direction may be changed by driving a motor or the like, or the projection direction may be changed depending on the positional relationship between the second auxiliary light projection device (4B) and the photographing lens (2). It is possible to make changes such as making it upper and lower or only left and right.

6> The specific configuration for the auxiliary light beam bundle in the first auxiliary light projection device (4A) and the second auxiliary light projection device (4B) can be changed as appropriate.
In B), instead of forming the projection pattern (16b) on the LED pellet (16), a film on which the projection pattern is printed is placed on the LED pellet (16) in the same way as the first auxiliary light projection device (4^). ) and the projection lens (17), or the LED pellet (16).
) may be made to have the same emission intensity in all parts. In addition, in the configuration in which the projection pattern (16b) is provided on the LED pellet (16), for example, the first
As shown in Figure 8, the metal layer (19) is omitted and the electrode (18
A projection pattern (16b) is formed only with a), and 5i02
The layer (16C) may prevent interference between the electrodes (18C). FIG. 19 shows a projection pattern (16b) according to the configuration shown in FIG. 18. In this projection pattern (16b), the vertical line on the right side is added to increase the contrast in the vertical direction.

〔Effect of the invention〕

As described above, the distance measuring device according to the present invention changes the projection position and projection direction of the detection pattern for assisting distance measurement, so that even if the projection angle of the detection pattern is small, it can be used to detect objects far away from nearby objects. It becomes possible to project a detection pattern onto various objects located in a wide range up to the object of There is no need to install different auxiliary light projection devices for each area where the target is located.
By reducing the projection angle of the detection pattern and narrowing down the beam of light projected from the light source with the same emission intensity, it has become possible to project the detection pattern in a state where sufficient contrast can be displayed even to objects further away.

Furthermore, by projecting a position detection pattern along with the detection pattern and receiving light from the position detection pattern, it is possible to determine whether or not the light beam from the detection pattern is incident on the optical measuring means. As described above, although the configuration allows changing the location where the detection pattern is projected, it is possible to easily find a state where distance measurement can be performed using the detection pattern as an aid when changing the location, which improves operability. does not decrease significantly.

Therefore, overall, it is possible to use an auxiliary light projection device to project a detection pattern onto an object at low brightness, and use the contrast obtained by the detection pattern to assist in distance detection using an optical measuring means, which requires less consumption. It is now possible to provide a distance measuring device that can perform distance detection using electric power as an aid to detecting patterns projected onto various objects over a wide range.

[Brief explanation of the drawing]

1 to 17 show embodiments of the distance measuring device according to the present invention, FIG. 1 is an optical path diagram, FIG. 2 is a perspective view of a camera,
Fig. 3 is a schematic perspective view of the focus detection optical system and its surroundings, Fig. 4 is a field view in the finder, Fig. 5 is a schematic perspective view of the first auxiliary light projection device, and Fig. 6 is the first auxiliary light projection device. 7(a) and 7(a) are schematic diagrams showing the relationship between the projection pattern and the focus detection area, FIG. 8 is a schematic perspective view of the second auxiliary light projection device, and FIG. 9 is a schematic diagram showing the relationship between the projection pattern and the focus detection area. 10 is a cross-sectional view along the line x-X in FIG. 9, FIG. 11 is a front view of the board for the LED pellet of the second auxiliary light projection device, and FIG. 12 is a front view of the LED pellet of the second auxiliary light projection device. A graph of the light emission intensity of the second auxiliary light projection device, FIG. 13 is an exploded perspective view of the second auxiliary light projection device, FIG. 14 is an enlarged sectional view of the adjustment screw part of the second auxiliary light projection device, and FIG. 15 is an exploded perspective view of the second auxiliary light projection device. Schematic block diagram of the camera,
FIG. 16 is a circuit diagram of the LED drive circuit, and FIG. 17 is a flowchart of the focus detection operation of the camera. 18 and 19 show another embodiment, with FIG. 18 being a sectional view corresponding to FIG. 10, and FIG. 19 being a front view corresponding to FIG. 9. (4B)......Auxiliary light projection device, (Po), (P
O, ), (PO2)... Light receiving element group.

Claims (1)

[Claims] An optical measuring means is provided for measuring the distance to the object using an image of the object formed through an imaging optical system on a group of light receiving elements arranged in a row, and the group of light receiving elements is placed on the object. An auxiliary light projection device is provided at a position away from the optical axis of the imaging optical system for projecting a detection pattern for distance measurement assistance in which bright areas and dark areas are arranged alternately along the juxtaposition direction of the target object. A distance measuring device comprising an object brightness detection means for detecting the brightness of the object, and an auxiliary light projection control means for controlling the operation of the auxiliary light projection device based on the detection result of the object brightness detection means. A projection changing means is provided for changing the emission position or the emission direction of the light projection device with respect to the optical axis of the imaging optical system, and a position detection pattern in which bright areas and dark areas are lined up is projected along the changing direction. A position detection light projection device is provided in a state where the emission position or emission direction is changed in conjunction with a change in the emission position or emission direction of the auxiliary light projection device, and the beam flux from the position detection pattern is changed. A distance measuring device comprising a light receiving means for receiving light and determining whether or not a beam from the detection pattern is included in a measurement target area of the optical measuring means.